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semiconductor_scirepeval_v1

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[ { "abstract": "Driven by the need to reduce the power consumption of mobile devices, and servers/data centers, and yet continue to deliver improved performance and experience by the end consumer of digital data, the semiconductor industry is looking for new technologies for manufacturing integrated circuits (ICs) In this quest, power consumed in transferring data over copper interconnects is a sizeable portion that needs to be addressed now and continuing over the next few decades. 2.5D Through Si Interposer (TSI) is a strong candidate to deliver improved performance while consuming lower power than in previous generations of servers/data centers and mobile devices. These low power/high performance advantages are realized through achievement of high interconnect densities on the TSI (higher than ever seen on Printed Circuit Boards (PCBs) or organic substrates) and enabling heterogeneous integration on the TSI platform where individual ICs are assembled at close proximity <1 mm separation) compared with several centim.", "author_names": [ "Xiaowu Zhang", "Jong-Kai Lin", "Sunil Wickramanayaka", "Songbai Zhang", "Roshan Weerasekera", "Rahul Dutta", "Ka Fai Chang", "King Jien Chui", "Hongyu Li", "David Ho", "Liang Ding", "Guruprasad Katti", "Suryanarayana Shivakumar Bhattacharya", "Dim Lee Kwong" ], "corpus_id": 55094853, "doc_id": "55094853", "n_citations": 62, "n_key_citations": 0, "score": 1, "title": "Heterogeneous 2.5D integration on through silicon interposer", "venue": "", "year": 2015 }, { "abstract": "The optimal selection of an interposer substrate is important in 2.5D systems, because its physical, material and electrical characteristics govern the overall system performance, reliability and cost. Several materials have been proposed that offer various tradeoffs including silicon, organic, glass and etc. In this paper, we conduct a quantitative comparison between two 2.5D IC designs based on silicon vs. liquid crystal polymer (LCP) interposer technologies in the overall system level for the first time. We also investigate tradeoffs in power, performance and area (PPA) signal integrity (SI) and power integrity (PI) depending on the interposer technologies. Through our flow, we generate a large scale benchmark architecture with commercial grade GDS layouts of interposer and chiplets using two different interposer substrates. Then, we model transmission lines and power delivery network (PDN) of each 2.5D IC design. Finally, we perform PPA analysis, SI and PI on both 2.5D IC designs to observe the quantitative tradeoffs between two designs. Our experiment shows that silicon interposer based design has 10.46% less power, 0.25x smaller area and 0.57x shorter average wirelength compared to LCP interposer based design. However, LCP based design has 0.59x smaller PDN DC impedance and 0.75x shorter worst delay of interposer wire while maintaining the power delivery efficiency. Lastly, our cost analysis of 2.5D IC design indicates that the overall cost of organic LCP technology, if both the chiplets and their interposer costs are combined, is 2.69x higher than the silicon even the cost of LCP interposer is 1.91% of silicon interposer. This indicates that LCP technology is prohibitive unless the interconnect and bump dimensions are dramatically reduced.", "author_names": [ "Jinwoo Kim", "Venkata Chaitanya Krishna Chekuri", "Nael Mizanur Rahman", "Majid Ahadi Dolatsara", "Hakki Mert Torun", "Madhavan Swaminathan", "S Mukhopadhyay", "Sung Kyu Lim" ], "corpus_id": 229375937, "doc_id": "229375937", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Silicon vs. Organic Interposer: PPA and Reliability Tradeoffs in Heterogeneous 2.5D Chiplet Integration", "venue": "2020 IEEE 38th International Conference on Computer Design (ICCD)", "year": 2020 }, { "abstract": "Silicon interposers are providing interesting alternatives to organic packages for the fabrication of complex system in package (SIP) modules in particular for RF application. Among the advantages of this technology are the capability to fabricate fine pitch redistribution layers and to embed inside the interposer some high quality passive elements very close to the active chips resulting in a highly integrated solution. To keep the technology at a reasonable cost these last add on features need to be fabricated with no or minor additional process steps that the ones needed for the fabrication of the interposer itself. In this work we present the design and the fabrication of a high resistive silicon interposer conceived for hosting a functional RF SIP transceiver including a Front End Module (FEM) a Dual Band Dual Mode Power Amplifier working at 400 and 900 MHz and some embedded planar and 3D inductors. The interposer consists in symmetrical stack with one thick level of copper RDL on each side of the 200 um thin HR silicon substrate and connected with through silicon via last (TSV last) The inductors are built with no additional metallization level. For the inductors development, a dedicated test vehicle was first designed to study different designs including planar spirals and 3D solenoids and torus. Simulation work was first carried out for dimensioning the structures to target inductance values in the range of 0.5 to 10 nH and high quality factor greater than 20. We present the process used for the fabrication, in particular the realization of the thick copper RDL layers on both sides of the interposer and the of the TSV last module. Physical characterization are presented showing the integrity and the good control of the technology. DC and RF electrical measurements assess the performances achieved for the different inductor variants exhibiting low resistance, constant inductance up to 5 GHz and factor of quality higher than 30. The functional RF transceiver SIP module will be then presented. The architecture is an extremely compact multi chip module composed of four actives CMOS chips (VGA, VCO, modulator and the PA) stacked by flip chip with Cu/SnAg ubumps on the HR silicon interposer and surrounded by a hundred of passive SMD components. With this technology the footprint of the module is reduced by a factor of 2 in comparison with the same module made on a uPCB substrate. The signals and ground are fed through the thick copper RDL lines and the TSVs from LGA pads present on the backside of the interposer for assembly on a test board. Different design configurations are made on the same wafer that include some version using only SMD inductors and some using 2.5 and 3D inductors in order to compare the corresponding performances. Other test structures are also present like filters and individual inductors for DC and RF characterization. We will finally present the resulting performances obtained from this SIP integration.", "author_names": [ "Gabriel Pares", "Michel Jean-Philippe", "Deschaseaux Edouard", "Ferris Pierre", "Serhan Ayssar", "Giry Alexandre" ], "corpus_id": 201741368, "doc_id": "201741368", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Highly Compact RF Transceiver Module Using High Resistive Silicon Interposer with Embedded Inductors and Heterogeneous Dies Integration", "venue": "2019 IEEE 69th Electronic Components and Technology Conference (ECTC)", "year": 2019 }, { "abstract": "As faster data processing and communication gets more demanded for Data Center/Cloud, HPC (High Performance Computing) AI (Artificial Intelligence) accelerator and Network markets, HBM (High Bandwidth Memory) becomes main memory type to meet the required bandwidth performance. HBM integration with logic dies in a system level has been developed on 2.5D SiP (System in Package) Platform with Si Interposer having TSV (Through Silicon Vias) of which fabrication cost is rather high. Therefore, as the low cost solution, alternative 2.5D SiP Platform approaches such as Organic Interposer using Redistribution Layer (RDL) and Glass Interposer have recently been reported. In this paper, RDL Interposer package with 4 HBM and 1 logic is demonstrated as 2.5D package platform based on RDL First Fan out Wafer Level Package (FOWLP) The effect of RDL design factors on electrical performances is investigated using the eye diagram method and fine pitch multi layer RDL structure (2um L/S RDL, 4 Layers) is designed accordingly. Fine pitch RDL process is established followed by the wafer level and unit level assembly processes and RDL Interposer package is confirmed to meet all the reliability requirements.", "author_names": [ "Jae-gwon Jang", "Kyoung-Lim Suk", "Seok-Hyun Lee", "Jin-Woo Park", "Gwang-jae Jeon", "Jung-ho Park", "Jeong-gi Jin", "Su-chang Lee", "Gyoung-bum Kim", "Joo-yeon Choi", "Dae-woo Kim", "Dan Oh", "Won-Kyoung Choi" ], "corpus_id": 232374426, "doc_id": "232374426", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Advanced RDL Interposer PKG Technology for Heterogeneous Integration", "venue": "2020 International Wafer Level Packaging Conference (IWLPC)", "year": 2020 }, { "abstract": "As the costs of advanced node silicon have risen sharply with the 7 and 5 nanometer nodes, advanced packaging is coming to a crossroad where it is no longer fiscally prudent to pack all desired functionality into a single die. While single die packages will still be around, the high end market is shifting towards multiple die packages to reduce overall costs and improve functionality. This shift is not just to add local memory, such as the addition of high bandwidth memory (HBM) module(s) to an application specific integrated circuit (ASIC) die, but also to separate what would have been a monolithic ASIC in prior generations to its constituent parts, such as the central processing unit (CPU) cores, serializer/deserializer (SerDes) and input/output (I/O) blocks. By splitting the monolithic die into smaller functional blocks, costs can be reduced through improved wafer yield on the smaller CPU cores and re using older, vetted intellectual property (IP) from a prior silicon node for the I/O and SerDes that do not necessarily need the most advanced silicon node.The traditional approach to fine pitch multi die packaging has been silicon interposers with Through Silicon Vias (TSVs) While the TSV approach has ushered in new performance levels never seen before, one of the major limitations is the inability to scale with higher and higher frequencies. The maximum frequency that a silicon interposer can handle between die to die interconnects is approximately 4 GHz due to the parasitics of the silicon. As dieto die interconnects increase their bandwidth to higher and higher levels, the 4 6 GHz limitation can become a major bottleneck. Eliminating the silicon and silicon dioxide dielectrics and using polymers as the dielectric and the interposer itself can solve this problem.This paper will discuss how to use High Density Fan Out (HDFO) technology to replace the TSV bearing silicon interposer with an organic interposer to enable higher bandwidth die to die interconnects for heterogeneous integration.", "author_names": [ "George Scott", "JaeHun Bae", "KiYeul Yang", "WonMyoung Ki", "Nathan Whitchurch", "Mike Kelly", "Curtis Zwenger", "JongHyun Jeon", "Taekyeong Hwang" ], "corpus_id": 225810842, "doc_id": "225810842", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Heterogeneous Integration Using Organic Interposer Technology", "venue": "2020 IEEE 70th Electronic Components and Technology Conference (ECTC)", "year": 2020 }, { "abstract": "To accommodate the exceedingly demanding power integrity (PI) requirements for the advanced artificial intelligence (AI) and high performance computing (HPC) components, high K (HK) based deep trench capacitors (DTC) have been integrated the first time in the silicon interposer with through silicon via (TSV) and fine pitch interconnects for chip on wafer on substrate (CoWoS) integration. A specific capacitance density (Cs) of up to 340 nF/mm2 is achieved over a large capacitor array, providing a total capacitance (Ct) of up to 68 mF per interposer die. The HK dielectric has intrinsic time dependent dielectric breakdown (TDDB) lifetime of 1,000 years at an operation voltage (Vcc) of 1.35V, and a normalized leakage current (ILK) density 1 fA/mm2 under 1.35V at 105deg C. No discernable process induced damage or performance degradation (capacitance, ILK Vbd tailing) were observed. The high capacitance, low leakage, large area and reliability proven Si interposer integrated DTC, or iCap, provides superior PI performance and therefore greatly enhances the merit of using CoWoS for the next generation heterogeneous wafer level system integration (WLSI)", "author_names": [ "S Y Hou", "C -H Wu", "Douglas Yu", "H Hsia", "Chung-Hao Tsai", "K C Ting", "Tsung-Hsin Yu", "Y W Lee", "F C Chen", "W C Chiou", "C -T Wang" ], "corpus_id": 211211998, "doc_id": "211211998", "n_citations": 5, "n_key_citations": 2, "score": 0, "title": "Integrated Deep Trench Capacitor in Si Interposer for CoWoS Heterogeneous Integration", "venue": "2019 IEEE International Electron Devices Meeting (IEDM)", "year": 2019 }, { "abstract": "A new trend in system on chip (SoC) design is chiplet based IP reuse using 2.5 D integration. Complete electronic systems can be created through the integration of chiplets on an interposer, rather than through a monolithic flow. This approach expands access to a large catalog of off the shelf intellectual properties (IPs) allows reuse of them, and enables heterogeneous integration of blocks in different technologies. In this article, we present a highly integrated design flow that encompasses architecture, circuit, and package to build and simulate heterogeneous 2.5 D designs. Our target design is 64 core architecture based on Reduced Instruction Set Computer (RISC) V processor. We first chipletize each IP by adding logical protocol translators and physical interface modules. We convert a given register transfer level (RTL) for 64 core processor into chiplets, which are enhanced with our centralized network on chip. Next, we use our tool to obtain physical layouts, which is subsequently used to synthesize chip to chip I/O drivers and these chiplets are placed/routed on a silicon interposer. Our package models are used to calculate power, performance, and area (PPA) and reliability of 2.5 D design. Our design space exploration (DSE) study shows that 2.5 D integration incurs $1.29\\times power and $2.19\\times area overheads compared with 2 D counterpart. Moreover, we perform DSE studies for power delivery scheme and interposer technology to investigate the tradeoffs in 2.5 D integrated chip (IC) designs.", "author_names": [ "Jinwoo Kim", "Gauthaman Murali", "Heechun Park", "Eric Qin", "Hyoukjun Kwon", "Venkata Chaitanya Krishna Chekuri", "Nael Mizanur Rahman", "Nihar Dasari", "Ashutosh Kumar Singh", "Minah Lee", "Hakki Mert Torun", "Kallol Roy", "Madhavan Swaminathan", "S Mukhopadhyay", "Tushar Krishna", "Sung Kyu Lim" ], "corpus_id": 225079697, "doc_id": "225079697", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Architecture, Chip, and Package Codesign Flow for Interposer Based 2.5 D Chiplet Integration Enabling Heterogeneous IP Reuse", "venue": "IEEE Transactions on Very Large Scale Integration (VLSI) Systems", "year": 2020 }, { "abstract": "Data intensive applications such as high performance computing (HPC) and artificial intelligence (AI) have recently become major subjects in industry. The heterogeneous integration of a chip and high bandwidth memories (HBMs) using through silicon via (TSV) based interposer has gained attractions to meet their performance requirements. An introduction of micro bump systems of these heterogeneous components (ex, a reticle limited GPU chip and HBMs) can created challenges in chip on wafer (COW) stacking. The impacts of heterogeneous micro bump systems and a giant GPU chip on COW stacking process are investigated in two micro pad systems. Micro bump system with adding a material layer or layers between Cu pillar and SnAg solder is found to be effective in modifying micro bump melting characteristics. It demonstrated the chip warpage dependent micro bump integrity. Micro bump joints formed by both micro pad systems passed reliability requirement without electrical, mechanical, microstructural failures.", "author_names": [ "Jaesik Lee", "Chun Yang Lee", "Chon-Su Kim", "Shantanu Kalchuri" ], "corpus_id": 51985416, "doc_id": "51985416", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Micro Bump System for 2nd Generation Silicon Interposer with GPU and High Bandwidth Memory (HBM) Concurrent Integration", "venue": "2018 IEEE 68th Electronic Components and Technology Conference (ECTC)", "year": 2018 }, { "abstract": "In this paper, a high resistivity silicon (HR Si) interposer integrated with through silicon via (TSV) electrically grounded coplanar waveguide (CPW) line is presented for 2.5 D/3 D heterogeneous integration of radio frequency (RF) microelectronics devices. In addition, design of TSV interconnection composed of two coaxial ladder hollow annular Cu (copper) TSVs of different diameters is utilized to maintain a sufficient freedom for strict standard cleaning to avoid Si resistivity degradation. The formation of the coaxial ladder TSV structure is more beneficial to the subsequent plating process because it reduces the aspect ratio of TSV vias. Hollow annular Cu TSV is manufactured in order to reduce the problem of mismatch in coefficient of thermal expansion among TSV's constituent materials. A layer of Au (aurum) film is utilized to passivate the exposed Cu surface of Si interposer. Au is widely used in III V groups' devices because of the good compatibility with photonic integrated circuits, conductivity, and corrosion resistance. HR Si interposer with TSV grounded CPW line and test structure is fabricated and characterized. With the monitoring test results, it can be found that it changes little in the resistivity of Si substrate, though the whole process, which is a basic requirement for RF performance. RF property test results show that the insertion loss is about 0.20 dB/mm at 10 GHz for the presented TSV grounded CPW line and 0.02 dB per TSV. These test results are better than the traditional design. To verify its applicability to 2.5 D/3 D heterogeneous integration, RF microelectronics die is assembled on TSV interposer and tested, and the test results prove that it works properly.", "author_names": [ "Jun Yan", "Shengli Ma", "Yufeng Jin", "Weiqi Wang", "Jing Chen", "Rongfeng Luo", "Han Cai", "Jiwei Li", "Yanming Xia", "Lilin Hu", "Shuwei He", "Zhongjun Tang" ], "corpus_id": 54207217, "doc_id": "54207217", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Fabrication and RF Property Evaluation of High Resistivity Si Interposer for 2.5 D/3 D Heterogeneous Integration of RF Devices", "venue": "IEEE Transactions on Components, Packaging and Manufacturing Technology", "year": 2018 }, { "abstract": "Recent advances in die stacking and 2.5D chip integration technologies introduce in package network heterogeneities that can complicate the interconnect design. Integrating chiplets over a silicon interposer offers new opportunities of optimizing interposer topologies. However, limited by the capability of existing network on chip (NoC) simulators, the full potential of the interposer based NoCs has not been exploited. In this paper, we address the shortfalls of prior NoC designs and present a new family of chiplet topologies called Kite. Kite topologies better utilize the diverse networking and frequency domains existing in new interposer systems and outperform the prior chiplet topology proposals. Kite decreased synthetic traffic latency by 7% and improved the maximum throughput by 17% on average versus Double Butterfly and Butter Donut, two previous proposals developed using less accurate modeling.", "author_names": [ "Srikant Bharadwaj", "Jieming Yin", "Bradford M Beckmann", "Tushar Krishna" ], "corpus_id": 222297184, "doc_id": "222297184", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Kite: A Family of Heterogeneous Interposer Topologies Enabled via Accurate Interconnect Modeling", "venue": "2020 57th ACM/IEEE Design Automation Conference (DAC)", "year": 2020 } ]

[ { "abstract": "1. Electromagnetic Fields and Waves 2. Rays and Optical Beams 3. Dielectric Waveguides and Optical Fibers 4. Optical Resonators 5. Interaction of Radiation and Atomic Systems 6. Theory of Laser Oscillation and Some Specific Laser Systems 7. Chromatic Dispersion and Polarization Mode Dispersion in Fibers 8. Nonlinear Optics 9. Electro Optics and AO modulators 10. Noise in Optical Detection and Generation 11. Detection of Optical Radiation 12. Periodic Structures 13. Waveguide Coupling 14. Nonlinear Optical Effects in Fibers 15. Semiconductor Lasers 16. Advanced Semiconductor Lasers 17. Optical Amplifiers 18. Classical Treatment of Quantum Optics, Quantum Noise, and Squeezing A. WAVE EQUATION IN CYLINDRICAL COORDINATES AND BESSEL FUNCTIONS B. EXACT SOLUTIONS OF THE STEP INDEX CIRCULAR WAVEGUIDE C. KRAMERS KRONIG RELATIONS D. TRANSFORMATION OF A COHERENT ELECTROMAGNETIC FIELD BY A THIN LENS E. FERMI LEVEL AND ITS TEMPERATURE DEPENDENCE F. ELECTRO OPTIC EFFECT IN CUBIC 43M CRYSTALS G. CONVERSION FOR POWER UNITS AND ATTENUATION UNITS", "author_names": [ "Amnon Yariv", "Pochi Albert Yeh" ], "corpus_id": 107100857, "doc_id": "107100857", "n_citations": 906, "n_key_citations": 70, "score": 1, "title": "Photonics optical electronics in modern communications", "venue": "", "year": 2006 }, { "abstract": "Thank you for reading Photonics Optical Electronics In Modern Communications The Oxford Series In Electrical And Computer Engineering. Maybe you have knowledge that, people have look hundreds times for their chosen readings like this Photonics Optical Electronics In Modern Communications The Oxford Series In Electrical And Computer Engineering, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they juggled with some malicious bugs inside their computer.", "author_names": [ "Amnon Yariv", "Pochi Albert Yeh" ], "corpus_id": 108537744, "doc_id": "108537744", "n_citations": 210, "n_key_citations": 12, "score": 0, "title": "Photonics: Optical Electronics in Modern Communications (The Oxford Series in Electrical and Computer Engineering)", "venue": "", "year": 1997 }, { "abstract": "Photonics, Plasmonics and Information OpticsInformation PhotonicsIntroduction to Information OpticsNeuromorphic PhotonicsMonolithic Nanoscale Photonics Electronics Integration in Silicon and Other Group IV ElementsOptical Fiber Communication Systems with MATLAB and Simulink ModelsCambridge Illustrated Handbook of Optoelectronics and PhotonicsAdvanced Digital Optical Communications, Second EditionPhotonic DevicesPhotonics and Fiber OpticsSilicon Photonics for Telecommunications and BiomedicineRF Photonic Technology in Optical Fiber LinksPhotonics, 6/EdHigh Speed and Lower Power TechnologiesPhotonics and Fiber OpticsWearable Electronics and PhotonicsSilicon PhotonicsLaser Diodes and Their Applications to Communications and Information ProcessingSilicon PhotonicsUndersea Fiber Communication SystemsPhotonicsOptical Fiber CommunicationsNoises in Optical Communications and Photonic SystemsSolutions Manual for Optical Electronics in Modern CommunicationsIntroduction to Fiber Optic CommunicationsInstructor's Solutions Manual for Photonics: Optical Electronics in Modern Communications, Sixth EditionAdvanced Optical Communication Systems and NetworksOptical Fiber Telecommunications VIIRaman Amplification in Fiber Optical Communication SystemsGraphene Photonics, Optoelectronics, and PlasmonicsOptical Fiber Communications SystemsQuantum ElectronicsApplied PhotonicsAn Introduction to Theory and Applications of Quantum MechanicsAdvances in Optical CommunicationOptics and PhotonicsNanoscale Photonics and OptoelectronicsNonlinear PhotonicsPhotonics and Electronics with GermaniumSilicon Photonics", "author_names": [], "corpus_id": 235272744, "doc_id": "235272744", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photonics Optical Electronics Communications", "venue": "", "year": 2021 }, { "abstract": "Semiconductor devices, circuits, and components are dependent upon miniaturization for transporting huge amounts of data at a high speed these provide the ability to control the transport and storage of electrons. Current communication systems are based on either electrons or photonics. These modern electronic devices for information processing and sensing are functioning almost close to their fundamental speed and bandwidth limitations which a serious problem. The performance of electronic circuits, as well as photonics, is now becoming rather limited when digital information needs to be sent from one point to another. Plasmonics is a new technology a kind of photonics based on surface plasmons viable. Surface plasmons are a way of guiding light. Surface Plasmon (SP) based circuits, which merge electronics and photonics at the nanoscale, may offer a solution to the size compatibility problem. Optical fiber communication (OFC) is a well known light enabled information transmission mechanism communicates very effectively over large distance. Surface plasmons, on the other hand, can guide light only over distances of tens or hundreds of microns. Surface plasmons are the electromagnetic (optical) waves get generated from the interaction between light and the mobile conduction electrons on the surface of a metal. The surface plasmons created by the interaction of light near the surface possess unique advantages like the high speed of communication which is very essential for the current generation of electrical and medical fields.", "author_names": [ "Mallikarjun G Hudedmani", "Bindu Suresh Pagad" ], "corpus_id": 204956437, "doc_id": "204956437", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Plasmonics: A Path to Replace Electronics and Photonics by Scalable Ultra fast Technology", "venue": "Advanced Journal of Graduate Research", "year": 2019 }, { "abstract": "A discipline that is fast emerging as an important component in modern high speed data transfer and communications technology is microwave photonics (MWP) MWP studies and applies the interaction between microwave and optical waves (light and radio waves) for high speed applications, typically aimed at the millimeter wave (mm wave) frequency spectrum.", "author_names": [ "Wynand Lambrechts", "Saurabh Sinha" ], "corpus_id": 138630637, "doc_id": "138630637", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Microwave Photonics: Complementing Light Wave Technology with High Speed Electronics", "venue": "", "year": 2017 }, { "abstract": "Modern electronics is based on semiconductor nanostructures in practically all main parts: from microprocessor circuits and memory elements to high frequency and light emitting devices, sensors and photovoltaic cells. Metal Oxide Semiconductor Field Effect Transistor (MOSFET) with ultimately low gate length in the order of tens of nanometers and less is nowadays one of the basic elements of microprocessors and modern electron memory chips. Principally new physical peculiarities of semiconductor nanostructures are related to quantum effects like tunneling of charge carriers, controlled changing of energy band structure, quantization of energy spectrum of a charge carrier and a pronounced spin related phenomena. Superposition of quantum states and formation of entangled states of photons offers new opportunities for the realization of quantum bits, development of nanoscale systems for quantum cryptography and quantum computing. Advanced growth techniques such as molecular beam epitaxy and chemical vapour epitaxy, atomic layer deposition as well as optical, electron and probe nanolithography for nanostructure fabrication have been widely used. Nanostructure characterization is performed using nanometer resolution tools including high resolution, reflection and scanning electron microscopy as well as scanning tunneling and atomic force microscopy. Quantum properties of semiconductor nanostructures have been evaluated from precise electrical and optical measurements. Modern concepts of various semiconductor devices in electronics and photonics including single photon emitters, memory elements, photodetectors and highly sensitive biosensors are developed very intensively. The perspectives of nanostructured materials for the creation of a new generation of universal memory and neuromorphic computing elements are under lively discussion. This paper is devoted to a brief description of current achievements in the investigation and modeling of single electron and single photon phenomena in semiconductor nanostructures, as well as in the fabrication of a new generation of elements for micro nano, optoelectronics and quantum devices.", "author_names": [ "A L Aseev", "Alexander V Latyshev", "A V Dvurechenskii" ], "corpus_id": 221797079, "doc_id": "221797079", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Semiconductor Nanostructures for Modern Electronics", "venue": "", "year": 2020 }, { "abstract": "Using plasmonics, photonics, and electronics, a nonvolatile memory cell operated both electrically and optically is demonstrated. Modern day computers rely on electrical signaling for the processing and storage of data, which is bandwidth limited and power hungry. This fact has long been realized in the communications field, where optical signaling is the norm. However, exploiting optical signaling in computing will require new on chip devices that work seamlessly in both electrical and optical domains, without the need for repeated electrical to optical conversion. Phase change devices can, in principle, provide such dual electrical optical operation, but assimilating both functionalities into a single device has so far proved elusive owing to conflicting requirements of size limited electrical switching and diffraction limited optical response. Here, we combine plasmonics, photonics, and electronics to deliver an integrated phase change memory cell that can be electrically or optically switched between binary or multilevel states. Crucially, this device can also be simultaneously read out both optically and electrically, offering a new strategy for merging computing and communications technologies.", "author_names": [ "Nikolaos Farmakidis", "Nathan Youngblood", "Xuan Li", "James Tan", "Jacob L Swett", "Zengguang Cheng", "C David Wright", "Wolfram H P Pernice", "Harish Bhaskaran" ], "corpus_id": 54075436, "doc_id": "54075436", "n_citations": 50, "n_key_citations": 1, "score": 0, "title": "Plasmonic nanogap enhanced phase change devices with dual electrical optical functionality", "venue": "Science Advances", "year": 2019 }, { "abstract": "In the process of design, a developer of new microwave photonics based RF apparatuses is facing a problem of choosing appropriate software. As of today, the existing optical and optoelectronic CAD tools (OE CAD) are not developed like CAD tools intended for modeling of RF circuits (E CAD) On the contrary, operating at symbolic level, modern high power microwave E CAD tools simply and with high precision solve this problem, but there are no models of active photonic components in their libraries. To overcome this problem, we proposed and validated experimentally a new approach to model a broad class of promising analog microwave radio electronics systems based on microwave photonics technology. This chapter reviews our known, updated, new models and simulation results using microwave electronics off the shelf computer tool NI AWRDE to pursue advanced performances corresponding to the last generation of key photonics structural elements and important RF devices on their basis.", "author_names": [ "Vladislav V Golovin", "Yuri Tyschuk", "Mikhail G Vasil", "", "Alexander S Sigov" ], "corpus_id": 201086772, "doc_id": "201086772", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chapter 4 Computer Aided Design of Microwave Photonics Based RF Circuits and Systems", "venue": "", "year": 2019 }, { "abstract": "Microwave measurement refers to the acquisition of parameters of a microwave signal or the identification of properties of an object via microwave based approaches. Thanks to the broad bandwidth and high speed provided by modern photonics, microwave measurement in the optical domain can provide better performance in terms of bandwidth and speed which may not be achievable using traditional, even state of the art electronics. In this tutorial, techniques for photonics based broadband and high speed microwave measurement are discussed with an emphasis on the system architectures for microwave signal parameter measurement and object property identification. Emerging technologies in this area and possible future research directions are also discussed.", "author_names": [ "Shilong Pan", "Jianping Yao" ], "corpus_id": 38766675, "doc_id": "38766675", "n_citations": 132, "n_key_citations": 3, "score": 0, "title": "Photonics Based Broadband Microwave Measurement", "venue": "Journal of Lightwave Technology", "year": 2017 }, { "abstract": "Silicon dioxide, also known as silica, is commonly found in nature, in sand or quartz, and is one of the most abundant chemical compounds on earth. Humans discovered how to transform the silica into silicon, and today almost all of our modern technology is based on this single starting material. The four basic elements of electronics are: (1) electrons as carrier vectors, (2) electrical cables and circuits, (3) the generators and (4) transistors. Progress in photonics provides the opportunity to replace electron flow, for transmission and computing, with a photonic flow or a plasmonic flow; harnessing the interaction between the surface electrons of nanostructured circuits and photons. The information carrier vectors in photonics can be photons, solitons, light balls, or plasmons. The plasmon is a quasi particle associated with the plasma oscillations of free electron density. The association of this particle, resulting from existing electrons present in the material and injected photons, offers at least two, unique, highly important benefits: (1) the possibility to transmit information with higher frequency (about 100 THz) and (2) the ability to confine light in very small dimension objects. Lasers and spasers are the optical equivalent of electrical generators; optical wave guides and optical fibers act as the transport cables; and plasmonsters and optical transistors are the equivalents of electrical switches and electronic transistors. These new photonic structures are very similar to those found in electronics. For instance, in transparent flexible electronics and in", "author_names": [ "Mihaela Girtan" ], "corpus_id": 111377037, "doc_id": "111377037", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Is photonics the new electronics", "venue": "", "year": 2014 } ]

[ { "abstract": "In this paper, we derive a coupled Schrodinger drift diffusion self consistent stationary model for quantum semiconductor device simulations. The device is decomposed into a quantum zone (where quantum effects are expected to be large) and a classical zone (where they are supposed negligible) The Schrodinger equation is solved for scattering states in the quantum zone while a drift diffusion model is used in the classical zone. The two models are coupled through interface conditions which are derived from those of N. Ben Abdallah (1998, J. Star. Phys. 90, 627) through a diffusion approximation. Numerical tests in the case of a resonant tunneling diode illustrate the validity of the method.", "author_names": [ "Pierre Degond", "Asma El Ayyadi" ], "corpus_id": 123119474, "doc_id": "123119474", "n_citations": 40, "n_key_citations": 7, "score": 1, "title": "A coupled Schrodinger drift diffusion model for quantum semiconductor device simulations", "venue": "", "year": 2002 }, { "abstract": "We consider a one dimensional coupled stationary Schrodinger drift diffusion model for quantum semiconductor device simulations. The device domain is decomposed into a part with large quantum effects (quantum zone) and a part where quantum effects are negligible (classical zone) We give boundary conditions at the classic quantum interface which are current preserving. Collisions within the quantum zone are introduced via a Pauli master equation. To illustrate the validity we apply the model to three resonant tunneling diodes.", "author_names": [ "Michael Baro", "Naoufel Ben Abdallah", "Pierre Degond", "Asma El Ayyadi" ], "corpus_id": 10295050, "doc_id": "10295050", "n_citations": 27, "n_key_citations": 5, "score": 0, "title": "A 1D coupled Schrodinger drift diffusion model including collisions", "venue": "", "year": 2005 }, { "abstract": "We propose a design for a semiconductor structure emitting broadband light in the infrared, based on InAsquantum dots(QDs) embedded into a metamorphic step graded InxGa1 xAs buffer. We developed a model to calculate the metamorphic QD energy levels based on the realistic QD parameters and on the strain dependent material properties; we validated the results of simulations by comparison with the experimental values. On this basis, we designed a p i n heterostructure with a graded index profile toward the realization of an electrically pumped guided wave device. This has been done by adding layers where QDs are embedded in InxAlyGa1 x yAs layers, to obtain a symmetric structure from a band profile point of view. To assess the room temperature electro luminescenceemission spectrum under realistic electrical injection conditions, we performed device level simulations based on a coupled drift diffusion and QD rate equation model. On the basis of the device simulation results, we conclude that the present proposal is a viable option to realize broadband light emitting devices.", "author_names": [ "Luca Seravalli", "Mariangela Gioannini", "Federica Cappelluti", "Fabio Sacconi", "Giovanna Trevisi", "P Frigeri" ], "corpus_id": 217966144, "doc_id": "217966144", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Broadband light sources based on InAs/InGaAs metamorphic quantum dots", "venue": "", "year": 2016 }, { "abstract": "We propose a design for a semiconductor structure emitting broadband light in the infrared, based on InAs quantum dots (QDs) embedded into a metamorphic 4 step graded InxGa1 xAs buffer with x 0.10, 0.20, 0.30, 0.40. We developed a model to calculate metamorphic QD energy levels based on realistic QD parameters and on strain dependent material properties: results of simulations were validated against experimental values. By simulating the broadband metamorphic structure, we demonstrated that its light emission can cover the whole 1.0 1.7 mm range with a bandwidth of 550 nm at 10K. The emission spectrum was then assessed under realistic electrical injection conditions, at room temperature, through device level simulations based on a coupled drift diffusion and QD dynamics model. As metamorphic QD devices have been already fabricated with satisfying performances we believe that this proposal is a viable option to realize broader band light emitting devices such as superluminescent diodes.", "author_names": [ "Luca Seravalli", "Mariangela Gioannini", "Federica Cappelluti", "Fabio Sacconi", "Giovanna Trevisi", "P Frigeri" ], "corpus_id": 112441087, "doc_id": "112441087", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Modelling of broadband light sources based on InAs INxGA1 xAS metamorphic quantum dots", "venue": "", "year": 2015 }, { "abstract": "Our simulations on InP based edge emitting RW lasers have been essentially based on the drift diffusion approach. The model comprises a self consistent description of the electronic properties and the optical field under modifications caused by heating processes. Calculations on the device performance have been done by means of the semiconductor device simulation package TESCA with energy transport equation. The quantum confined carriers are described by a (8X8) kp Hamiltonian, self consistently coupled to the Poisson equation and exchange correlation potentials to give a guess for Coulomb effects. Using the package KPLIB for band structure calculations, modifications of the optical gain, caused by the presence of the strained multi quantum wells, have been simulated and will be discussed.", "author_names": [ "Uwe Bandelow", "Herbert Gajewski", "Hans-Christoph Kaiser" ], "corpus_id": 120058332, "doc_id": "120058332", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Modeling combined effects of carrier injection, photon dynamics, and heating in strained multiple quantum well lasers", "venue": "Photonics West Optoelectronic Materials and Devices", "year": 2000 }, { "abstract": "Abstract In this study, we consider the three dimensional quantum bipolar drift diffusion model arising from the semiconductor device simulation, which consists of the coupled nonlinear fourth order parabolic equation and Poisson equation. Based on the results of the self similar stability for the one dimensional quantum bipolar drift diffusion equation, we show the stability of planar self similar wave for the three dimensional quantum bipolar drift diffusion model. Using the energy methods, we present the global existence of smooth solutions for the initial value problem of the three dimensional quantum bipolar drift diffusion equation when the initial data are close to the planar self similar wave. We also show that in large time, the solution of the three dimensional quantum bipolar drift diffusion equations tends to the planar self similar wave, at an algebraic time decay rate.", "author_names": [ "Fang Liu", "Yeping Li" ], "corpus_id": 213670216, "doc_id": "213670216", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Large time behavior of solution to the three dimensional quantum bipolar drift diffusion model from semiconductors", "venue": "", "year": 2020 }, { "abstract": "The device scale simulation of electrically driven quantum light sources based on semiconductor quantum dots requires a combination of the (classical) semiconductor device equations with cavity quantum electrodynamics. In this paper, we extend our previously developed hybrid quantum classical model system where we have coupled the drift diffusion system with a Lindblad type quantum master equation by including a self consistent Schrodinger Poisson problem. The latter describes the (quasi )bound states of the quantum dot carriers. The extended model allows to describe the bias dependency of the emission spectrum due to the quantum confined Stark effect.", "author_names": [ "Markus Kantner" ], "corpus_id": 201621987, "doc_id": "201621987", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Simulation of quantum light sources using the self consistently coupled Schrodinger Poisson Drift Diffusion Lindblad syste", "venue": "2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD)", "year": 2019 }, { "abstract": "A modified quantum drift diffusion (QDD) model is developed for non linear analysis of SiC (4H, 6H and 3C polytypes) pin semiconductor diodes at W band frequency regime. Effects of incorporation of a buffer layer (n type) in between substrate and low doped active region of the hexagonal (4H and 6H) pin (p+ p+ n n n+ vertical mesa structure is thoroughly studied in this paper for the improvement of MM wave performance of the single device. Also, a thin layer of Ge has been introduced in between Si substrate and n+ cubic SiC layer in 3C SiC pin device for minimising the lattice mismatch issue in between Si/3C SiC interface. The comprehensive analysis establish that the forward characteristics, reverse recovery time (1 ns) and breakdown voltage (171 Volt) in case of 4H SiC device are quite good in comparison to its cubic (3C) and other hexagonal (6H) counterparts, however, the switching characteristics of 3C SiC pin diode array is comparatively better than its hexagonal counterparts. This observation could be explained in terms of lowest series resistance in 3C SiC based single pin device that has been achieved by incorporating Ge layer in mesa structure. The authors have made a comparative analysis among SPST, SPDT and SPMT pin switches made up with 4H, 6H and 3C SiC poly types. At 94 GHz, W band central frequency, series resistance in 4H SiC single device is 0.59 O, whereas, the same is much lower (0.27 O) in case of 3C SiC. Insertion loss and isolation in 3C SiC pin array of switches are found to be 0.18 dB and 38 dB (SPST switch) 0.19 dB and 67 dB (SPDT switch) 0.20 dB and 90 dB (SPMT shunt type switching array) and 0.23 dB and 74 dB (SPMT series shunt type switching array) This newly proposed QDD model validation is done through comparative studies between experiment and analytical results for 4H SiC SPST switches in low frequency Microwave region. The validated QDD model, coupled with PSpice and Comsol Multi physics simulator, then used for designing of the W band devices and corresponding switches. However, as far as author's knowledge is concerned, no experiment is yet done with SiC pin diodes at W band frequencies, in literature for comparison. From simulation point of view also such an extensive study on hexagonal and cubic SiC pin diode switches at W band region has not yet been done by any other researcher group. This paper, for the first time, establishes the feasibility and potentiality of IV IV group semiconductor based pin (p+ p+ n n n+ switches for W band applications. Comparative analysis also reveals that 3C SiC based shunt type pin (p+ p+ n n n+ SPMT switches are the best for MMW communication systems. Thermal modelling of the designed devices are also compared and reported in this paper. The quasi 3D thermal analysis is done to optimize the mesa and heat sink diameter/dimensions so as to minimize the thermal runaway issues. The results may further be used for developing low cost and fast semiconductor switches for potential application in THz communication systems.", "author_names": [ "Abhijit Kundu", "Maitreyi Ray Kanjilal", "Moumita Mukherjee" ], "corpus_id": 181840312, "doc_id": "181840312", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Cubic versus hexagonal SiC vertical pin SPST/SPDT/SPMT switches for MMW communication systems: a modified quantum drift diffusion model for switching characteristics analysis", "venue": "Microsystem Technologies", "year": 2019 }, { "abstract": "The device scale simulation of electrically driven solid state quantum light emitters, such as single photon sources and nanolasers based on semiconductor quantum dots, requires a comprehensive modeling approach, that combines classical device physics with cavity quantum electrodynamics. In a previous work, we have self consistently coupled the semi classical drift diffusion system with a Markovian quantum master equation in Lindblad form to describe (i) the spatially resolved current injection into a quantum dot embedded within a semiconductor device and (ii) the fully quantum mechanical light matter interaction in the coupled quantum dot photon system out of one box. In this paper, we extend our hybrid quantum classical modeling approach by including a Schroedinger Poisson problem to account for energy shifts of the quantum dot carriers in response to modifications of its macroscopic environment (e.g. quantum confined Stark effect due to the diode's internal electric field and plasma screening) The approach is demonstrated by simulations of a single photon emitting diode.", "author_names": [ "Markus Kantner" ], "corpus_id": 128025134, "doc_id": "128025134", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Hybrid modeling of quantum light emitting diodes: self consistent coupling of drift diffusion, Schrodinger Poisson, and quantum master equations", "venue": "OPTO", "year": 2019 }, { "abstract": "Electrons and holes injected into a semiconductor heterostructure containing quantum wells are captured with a finite time. We show theoretically that this very fact can cause a considerable excess contribution to the series resistivity and this is one of the main limiting factors to higher efficiency for GaAs based high power lasers. The theory combines a standard microscopic based model for the capture escape processes in the quantum well with a drift diffusion description of current flow outside the quantum well. Simulations of five GaAs based devices differing in their Al content reveal the root cause of the unexpected and until now unexplained increase of the series resistance with decreasing heat sink temperature measured recently. The finite capture time results in resistances in excess of the bulk layer resistances (decreasing with increasing temperature) from 1 mO up to 30 mO in good agreement with experiment.", "author_names": [ "Anisuzzaman Boni", "Hans-Juergen Wuensche", "Hans Wenzel", "P A Crump" ], "corpus_id": 219737833, "doc_id": "219737833", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Impact of the capture time on the series resistance of quantum well diode lasers", "venue": "", "year": 2020 } ]

[ { "abstract": "Being able to manipulate mass flow is critically important in a variety of physical processes in chemical and biomolecular science. For example, separation and catalytic systems, which requires precise control of mass diffusion, are crucial in the manufacturing of chemicals, crystal growth of semiconductors, waste recovery of biological solutes or chemicals, and production of artificial kidneys. Coordinate transformations and metamaterials are powerful methods to achieve precise manipulation of molecular diffusion. Here, we introduce a novel approach to obtain mass separation based on metamaterials that can sort chemical and biomolecular species by cloaking one compound while concentrating the other. A design strategy to realize such metamaterial using homogeneous isotropic materials is proposed. We present a practical case where a mixture of oxygen and nitrogen is manipulated using a metamaterial that cloaks nitrogen and concentrates oxygen. This work lays the foundation for molecular mass separation in biophysical and chemical systems through metamaterial devices.", "author_names": [ "Juan-Manuel Restrepo-Florez", "Martin Maldovan" ], "corpus_id": 18510472, "doc_id": "18510472", "n_citations": 10, "n_key_citations": 0, "score": 1, "title": "Mass Separation by Metamaterials", "venue": "Scientific reports", "year": 2016 }, { "abstract": "In this letter, we describe and study microwave Luneburg lenses using a broadband metamaterial composed of radially diverging dielectric rods. The gradual Luneburg's permittivity profile is achieved in this lens through arranging identical thin rods with a spatially variable cross section in various radial directions with a subwavelength separation. The performance of the considered metamaterial lenses was studied by full wave numerical simulation and measurements in an anechoic chamber. The results reveal that, although anisotropy of the structure causes aperture phase errors, the structure composed of diverging dielectric rods may still operate as a cylindrical or spherical Luneburg lens. Advantageously, the considered design is attractive for mass production of large scaled beam steering antennas because the lens is composed of identical shaped dielectric parts.", "author_names": [ "Andrey D Sayanskiy", "Stanislav B Glybovski", "Valerii Petrovich Akimov", "Dmitry S Filonov", "Pavel A Belov", "Igor K Meshkovskiy" ], "corpus_id": 22797767, "doc_id": "22797767", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "Broadband 3 D Luneburg Lenses Based on Metamaterials of Radially Diverging Dielectric Rods", "venue": "IEEE Antennas and Wireless Propagation Letters", "year": 2017 }, { "abstract": "Acoustic metamaterials are artificial structures with acoustic properties not found in natural materials.1 They consist of periodic arrangements of subwavelength units, each unit being a designed composite made of different materials and shapes. Since the building units and their separation are small in comparison with the sound wavelength, a metamaterial behaves as a homogeneous medium with exotic properties. A fluid or a gas can be acoustically characterized with two parameters, its mass density and its bulk modulus (B) Although these parameters always take positive values in natural materials, mass anisotropy and negative values of both parameters are possible under dynamical conditions using acoustic metamaterials.1 3 These unusual properties lead to novel phenomena such as negative refraction, and interesting applications such as superlensing or acoustic cloaks. This work focuses on metamaterials intended to work with waves traveling inside two dimensional ducts. One of the walls defining such a waveguide is drilled in order to insert a periodic arrangement of cylindrical cavities (see Figure 1) Since the cavities' length L extends along the third dimension, the resulting structures are named quasi two dimensional sonic crystals (Q2DSC) We found that they exhibit unusual properties due to the resonances embedded in the cavities. These properties appear at low frequencies, corresponding to wavelengths much larger than the cavity radius, R, and lattice separation, a. We fabricated Q2DSC sample consisting of a cluster made of 15 rows of 9 cylinders with R D 1cm, and covering an area of 47 25cm2 (see Figure 2) We characterized the sample in a Figure 1. Diagram of a simple quasi 2D sonic crystal. It consists of a periodic distribution of cylindrical cavities drilled in the upper surface of a waveguide with height h. The color pattern represents the sound propagation inside the waveguide. R: Cavity radius. L: Length. a: Lattice separation.", "author_names": [ "Daniel Torrent", "Victor M Garcia-Chocano", "Rogelio Gracia-Salgado", "Francisco Cervera", "Jose Sanchez-Dehesa" ], "corpus_id": 123480145, "doc_id": "123480145", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Quasi two dimensional acoustic metamaterials for sound control in ducts", "venue": "", "year": 2014 }, { "abstract": "The vibrational waves in a one dimensional composite system containing a series of mass in mass resonators that act as acoustic metamaterials were studied. Using a lattice model, the transmission of sound waves in single and double barrier systems was numerically clarified. In the double barrier system, characteristic frequencies were found to exist in a band gap range in which sharp peaks appeared in the transmission coefficient. The frequency dependence of wave transmission upon the thickness of the resonant block and the separation distance between the two resonant blocks was clarified.", "author_names": [ "Takamichi Terao" ], "corpus_id": 124211598, "doc_id": "124211598", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Wave propagation in acoustic metamaterial double barrier structures", "venue": "", "year": 2016 }, { "abstract": "", "author_names": [ "Juan-Manuel Restrepo-Florez", "Martin Maldovan" ], "corpus_id": 136329063, "doc_id": "136329063", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Metamaterials for mass separations", "venue": "", "year": 2017 }, { "abstract": "Recent advances in coordinate transformations of Fick's equation have paved the way for the design of metamaterial devices that can manipulate mass diffusion flux. The control of diffusion paths has a great potential for the design of novel catalytic and separation systems in chemical and biomolecular engineering. In order to explore these new applications, it is necessary to understand mass diffusion in coordinate transformation metamaterial devices. In this work, we present a comprehensive study on the impact of structure and material properties on the resultant physical properties of mass concentrator metamaterial shells. The concentration gradient at the core, the total mass flow rate towards the core, and the disturbance of the external concentration field are systematically examined in order to provide guidelines for the rational design and fabrication of metamaterial mass concentrators. A practical case is also presented where the concentration of oxygen diffusing in a polymeric system is studied.", "author_names": [ "Juan-Manuel Restrepo-Florez", "Martin Maldovan" ], "corpus_id": 125618840, "doc_id": "125618840", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Rational design of mass diffusion metamaterial concentrators based on coordinate transformations", "venue": "", "year": 2016 }, { "abstract": "Abstract Effect of the graded variation in terms of separation gap between the two successive resonators and their mass on the resultant band structure of the graded metabeam is investigated in this paper. The band structure are explored by implementing the transfer matrix method in conjunction with Bloch Floquet's theorem. The graded arrangement of oscillators modifies the relative position of the coupling coefficient in the transfer matrix, which plays a pivotal role in altering the band gap formation. The flexural band structure is highly sensitive to the natural frequency and the distance between two resonators. It is evidenced that around 20% shifting of attenuation band in lower frequency side and 2.5 times widening of overall attenuation band gap is achievable by proper graded arrangement of resonators in metamaterial unit cell. However, the level of attenuation deteriorates over the wider frequency range.", "author_names": [ "Arnab Banerjee" ], "corpus_id": 229395541, "doc_id": "229395541", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Flexural waves in graded metabeam lattice", "venue": "", "year": 2021 }, { "abstract": "Abstract Flexible and efficient mass manipulation is of critical importance in multiple fields of industrial separation, membrane science, chemical production, and biotechnology. Owing to the extensive investigation of transformation optics/thermodynamics, some pioneering attempts of mass diffusion metamaterial are proposed to motivate the traditional techniques. However, most of the current works are dependent on specific spatial transformations, thus leading to the conventional imperfects of transformation based metamaterial in mass manipulations. Here, we propose a bilayer meta device for binary masses manipulation (O2 and N2) by directly solving static Fick's law. Only homogeneous media are employed in such design owing to the independence of spatial transformations. The O2 avoiding and N2 concentrating behaviors with non distortion concentration fields reveal the manipulative significance. The findings may promote the research on mass diffusion metamaterial towards easy obtainment, and open up an avenue for innovating the conventional mass manipulation techniques.", "author_names": [ "Xue Zhou", "Guoqiang Xu", "Huiyan Zhang" ], "corpus_id": 233658994, "doc_id": "233658994", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Binary masses manipulation with composite bilayer metamaterial", "venue": "Composite Structures", "year": 2021 }, { "abstract": "", "author_names": [ "By Yang", "Dm Zhu", "Qf Hong", "Gq Sun", "Yk Zhang" ], "corpus_id": 99333863, "doc_id": "99333863", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "MATRIX ASSISTED LASER DESORPTION IONIZATION MASS SPECTROMETRIC METHOD FOR THE SEPARATION AND MOLECULAR WEIGHT DETERMINATION OF SNAKE VENOM PROTEINS", "venue": "", "year": 1994 }, { "abstract": "This talk will review recent results on the topic of sound propagation through periodic arrays of sonic scatterers embedded in a fluid or a gas. These structures, which are called phononic crystals, define in the homogenization limit (i.e. for lattice separations much lower than the sound wavelength) a class of acoustic metamaterials with extraordinary properties. For example, they are solid structures that are used to engineer effective fluid like systems with anisotropic dynamical mass density, a property that can be tailored by changing the parameters of the structure and the material composition of scatterers. A homogenization method based on multiple scattering theory has been developed and semianalytical expressions for the effective acoustic parameters will be given. By using these expressions it is easy to design novel refractive devices like gradient index sonic lens with a perfect match of impedance with the background. Results for a gradient index lens made of aluminum cylinders in air will be.", "author_names": [ "Jose Sanchez-Dehesa", "Daniel Torrent" ], "corpus_id": 122950655, "doc_id": "122950655", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Acoustic metamaterials based on phononic crystals.", "venue": "", "year": 2010 } ]

[ { "abstract": "Abstract We investigate the synchronization in coupled time delayed semiconductor laser models without and under the influence of external noise sources. The synchronization and its robustness are observed by mean synchronization error and the effect of parameter mismatch respectively. A communication scheme is introduced based on symmetrical encryption and decryption method in the frame of coupled synchronized lasers with optical feedback. The scheme is effective irrespective of the nature and dynamics of the transmitted signal. The security of the scheme is verified by the effect of relative parameter mismatch, key sensitivity frequency and cross correlation analysis. Numerical results support the proposed analysis.", "author_names": [ "Thang Manh Hoang", "Sanjay Kumar Palit", "Sayan Mukherjee", "Santo Banerjee" ], "corpus_id": 114914505, "doc_id": "114914505", "n_citations": 10, "n_key_citations": 0, "score": 1, "title": "Synchronization and secure communication in time delayed semiconductor laser systems", "venue": "", "year": 2016 }, { "abstract": "An observer design problem for a class of nonlinear time delay systems subject to white Gaussian noise is studied. The problem addressed is the design of a full state observer based on the extended Kalman filter (EKF) in which two terms are added to the Riccati differential equation. One of those makes the system robust to noise influences, and the other one is utilized for dealing with the delayed state. A Lyapunov Krasovskii functional is used for giving sufficient conditions for local stability of the reconstruction error dynamics. A hybrid chaotic cryptosystem procedure based on the n shift cipher is combined with synchronization based on the EKF for developing a secure communication system. A semiconductor laser with optical feedback is employed as a chaotic signal generator in which a full state estimation via the EKF is achieved.", "author_names": [ "Oscar Hugues-Salas", "K Alan Shore" ], "corpus_id": 37719510, "doc_id": "37719510", "n_citations": 24, "n_key_citations": 1, "score": 0, "title": "An Extended Kalman Filtering Approach to Nonlinear Time Delay Systems: Application to Chaotic Secure Communications", "venue": "IEEE Transactions on Circuits and Systems I: Regular Papers", "year": 2010 }, { "abstract": "A novel bandwidth enhanced bidirectional phase chaotic secure communication system with time delay signature (TDS) concealment is proposed and analyzed by numerical simulation. This bidirectional system based on two mutually coupled electro optic (MCEO) phase feedback loops is driven by a common all optical (AO) chaotic source. The AO driving source makes the amplitude and phase terms in the Ikeda based MCEO equation chaotic. Two mutually coupled optoelectronic delayed feedback loops also greatly increase the complexity of the chaotic carrier. By replacing the semiconductor laser in the existing bidirectional communication scheme with an electro optic feedback loop, the problems of narrow carrier bandwidth and poor synchronization performance can be compensated. Compared to the single MCEO system, the permutation entropy of the AO MCEO cascaded system with a bit rate of 10 Gbit/s is improved by 0.13 to 0.98. The TDS of the AO MCEO system is suppressed 35 times to less than 0.01 to be completely hidden when the EO gain is reduced by half to 2.75. The chaos effective bandwidth is increased by 5 GHz to 32.05 GHz, and the spectrum flatness is reduced by 0.33 dB/Hz to 0.82 dB/Hz. Meanwhile, the security is further enhanced by reducing the cross correlation coefficient to 0.001 between the AO driving source and the electro optical chaotic carrier. The results show that the proposed model has potential applications in bandwidth enhanced bidirectional secure chaotic systems.", "author_names": [ "Tianfeng Lu", "Hongxiang Wang", "Yuefeng Ji" ], "corpus_id": 222167396, "doc_id": "222167396", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wideband complex enhanced bidirectional phase chaotic secure communication with time delay signature concealment.", "venue": "Chaos", "year": 2020 }, { "abstract": "This study concentrates on the transmitter operating in the short cavity regime. Broadband chaotic dynamics of the transmitter is demonstrated with corresponding nearly \"white\" rf spectra. Under these conditions, the receiver laser is synchronized, revealing a conspicuous potential for secure, broadband and multi Gigabit rate communication systems, which are based on chaotic carriers and chaos synchronization. The influence of the injection current I/sub p/ and the delay time /spl tau//sub del/ on the dynamics of the transmitter laser operating in the short cavity regime is experimentally studied, in which the delay time of the optical feedback /spl tau//sub del/ is shorter than the period of the relaxation oscillation frequency of the laser /spl tau//sub ro/ It is demonstrated that for a well adjusted feedback phase and moderate I/sub p/ the bandwidth of the dynamics can be drastically enhanced compared to the results reported for lasers with longer cavities. Results show an almost \"white\" rf spectra extending up to frequencies of several GHz. The bandwidth of the system increases by reducing /spl tau//sub del/ or by increasing I/sub p/ respectively. Furthermore, the autocorrelation function of the dynamics decays rapidly, indicating a strong nonlinearity in the system. These properties are crucial demands on chaotic carriers for the realization of secure communication systems based on synchronization of chaotic carriers.", "author_names": [ "Michael Peil", "Tilmann Heil", "L Fischer", "W Elsafler", "Javier M Buldu" ], "corpus_id": 110932997, "doc_id": "110932997", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Chaos synchronization of semiconductor laser systems in an open loop configuration: the short cavity regime and its potential for secure communication systems", "venue": "2003 European Quantum Electronics Conference. EQEC 2003 (IEEE Cat No.03TH8665)", "year": 2003 }, { "abstract": "Abstract In this paper, we propose and study theoretically a novel architecture, which combines all optical intensity chaos and electrooptical phase chaos generator, allows for bidirectional secure communication. The configuration includes three all optical chaotic semiconductor lasers and two identical phase chaos electrooptic delayed oscillators in the optic fiber link. We investigate the complexity degree of this chaotic time trace generated in this system and the concealment of the time delay signature (TDS) and systematically analyze the influence of the parameter mismatch on synchronization performance We demonstrate that the system can generate the chaos with high complexity degree through a calculation of the largest Lyapunov exponent (LLE) Lempel Ziv complexity (LZC) permutation entropy (PE) and fractal box counting dimension (FBCD) the TDS of an electro optical delayed oscillator is concealed by calculating the autocorrelation function (ACF) and the delayed mutual information (DMI) the parameter mismatches, such as the TDS, the bias current, the line width enhancement factor (LWEF) etc. have the influence on the synchronization performance; the changes of the bit rate and the modulation index have the influence on Q factor of the system. Moreover, our numerical simulations also reveal that, under the parameter match condition the delayed chaotic dynamics can be identically synchronized and the synchronization solution is robust. At last, we successfully achieve the simultaneously bidirectional exchange of the messages introduced on the two sides of a link.", "author_names": [ "Qiliang Li", "Qi Bao" ], "corpus_id": 213385512, "doc_id": "213385512", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Bidirectional communication with time delay concealment in a system combining all optical intensity and electrooptical phase chaos", "venue": "", "year": 2020 }, { "abstract": "Abstract We numerically investigate the synchronization performance of unidirectionally and bidirectionally coupled chaotic semiconductor lasers subject to multiple modulated time delays optical feedbacks. Moreover, by studying the autocorrelation function of the coherent feedback semiconductor laser output, we find that the signatures of time delays can be erased in systems incorporating modulated feedback time delays, which largely improve the system security. Finally, chaos masking switching (CMS) is utilized to examine the communication ability. Numerical results indicate that the messages could be successfully recovered both in unidirectionally and bidirectionally coupled lasers, which confirms the possibility of applying multiple modulated delay system in optical chaos secure communication.", "author_names": [ "Juju Hu", "Kehui Jia", "Jun-shan Ma" ], "corpus_id": 109952103, "doc_id": "109952103", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Chaos synchronization and encoding in coupled semiconductor lasers of multiple modulated time delays", "venue": "", "year": 2011 }, { "abstract": "The synchronization in multiple modulated time delay chaotic lasers subject to incoherent optical feedbacks and incoherent optical injection is numerically investigated,in which the semiconductor lasers are subject to incoherent injection that fine tuning of optical frequency is not required.Otherwise,by studying the autocorrelation function of the incoherent feedback semiconductor laser output,it is found that the signatures of time delays can be erased in systems incorporating modulated feedback time delays,which property can improve the system security and is of importance for the suitability of such laser systems for secure chaos based communication systems.Finally,the encryption method of CSK and CMS is respectively utilized to examine the communication ability of the unidirectionlly and bidirectionly coupled system.", "author_names": [ "Wan Yun-hui" ], "corpus_id": 63455397, "doc_id": "63455397", "n_citations": 7, "n_key_citations": 1, "score": 0, "title": "Chaos synchronization and encoding in coupled semiconductor lasers of multiple modulated time delays", "venue": "", "year": 2010 }, { "abstract": "A closed loop system (CLS) of quantum dot semiconductor laser (QDL) with optical feedback is theoretically studied in this work. The CLS studied under two types of time delay (short and long) The system transit to chaos under short delay times, which important in secure optical communications. A complete synchronization was obtained at long delay time which is also important in the of coding and decoding for communication security applications.", "author_names": [ "Basim Abdullattif Ghalib", "Rajaa Hussein Abd Ali", "Amin Habbeb Al-Khursan" ], "corpus_id": 214408231, "doc_id": "214408231", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Effect of short and long delay times on closed loop system of quantum dot semiconductor lasers", "venue": "", "year": 2020 }, { "abstract": "To exam the chaotic dynamics of multiple modulated delays system, the synchronization in multiple constant and modulated time delay chaotic lasers subject to incoherent optical feedbacks and incoherent optical injection is numerically investigated, in which the semiconductor lasers are subject to incoherent injection that fine tuning of optical frequency is not required. Furthermore, the autocorrelation function of the incoherent feedback semiconductor laser output is also investigated. The results indicate that high quality of synchronization can be obtained under both the cases. However, the signatures of time delays under modulated delays case can be hidden, which largely improves the system security and is important for the suitability of such laser systems for secure chaos based communication systems.", "author_names": [ "Hu Ju-ju", "Ma Jun-shan" ], "corpus_id": 113266386, "doc_id": "113266386", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chaos synchronization in coupled semiconductor lasers of multiple modulated time delays", "venue": "", "year": 2010 }, { "abstract": "By studying the autocorrelation function of the optoelectronic feedback semiconductor laser output we establish that the signatures of time delays can be erased in systems incorporating modulated feedback time delays. This property is of importance for the suitability of such laser systems for secure chaos based communication systems. We also make the first report on chaos synchronization in both unidirectionally and bidirectionally coupled multiple time delay chaotic semiconductor lasers with modulated optoelectronic feedbacks.", "author_names": [ "" ], "corpus_id": 222175679, "doc_id": "222175679", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Erasure of Time Delay Signatures in the Output of an Optoelectronic Feedback Laser with Modulated Delays and Chaos Synchronization", "venue": "", "year": 2009 } ]

[ { "abstract": "Electronic Nose and Tongue in Food Science describes the electronic products of advanced chemical and physical sciences combined with intuitive integration of microprocessors, advanced bioinformatics and statistics. These include, for example, voltammetric, bio electronic, piezoelectric platforms made from a variety of components including, nanoparticles, enzyme biosensors, heavy metals, graphite epoxy composites, metal oxide semiconductors, microelectrodes, microfluidic channels, pre manufactured gas sensors, redox enzymes and others and is an ideal resource for understanding and utilizing their power in Food Science settings. Devices used to analyse one particular food item can theoretically be adapted for other food items or components. This does not just mean the re deploying the physical platforms but also the mode of bioinformatic and statistical analysis. This includes artificial neural networks (ANN) linear discriminant analysis (LDA) partial least squares (PLS) principal component analysis (PCA) etc. In other words, there is cross transference of chemistry, physics, concepts, techniques, findings and approaches from one food to another. Electronic noses and tongues are two of these devices but are advancing in application and importance. This book provides examples of the use of electronic noses and tongues to characterise components that contribute to sensory or compositional profiles, from ripening to harvesting and from storage of raw materials to packaging and consumption. These devises are suitable for high throughput analysis, quality control or to determine the nature and extent of spoilage and adulteration, and have also been used to ascertain the geographical origins of food and mixtures.Presents latest developments in the application of electronic nose and tongue technologies to a variety of food specific needsIncludes both electronic nose, electronic tongue and combined technology insightsEach chapter has sections on: The physical and chemical platforms; Analysis of specific foods; Applications to other foods and areas of food science", "author_names": [ "Rodriguez Mendez", "Mariane dos Santos Aguiar Luz" ], "corpus_id": 126169660, "doc_id": "126169660", "n_citations": 46, "n_key_citations": 0, "score": 1, "title": "Electronic Noses and Tongues in Food Science", "venue": "", "year": 2016 }, { "abstract": "In this paper, a hybrid electronic noses' system (HENS) based on MOS SAW detection units intended for lung cancer diagnosis is proposed. The MOS gas sensors are used to detect the VOC molecules with low molecular weight (LMW) and the SAW sensors are adopted for the detection of VOC with high molecular weight (HMW) Thus, the novel combination of these two kinds of gas sensors provides higher sensitivities to more of VOC species in breath than that of using only a single kind of sensor. The signals from MOS SAW detection units are then recognized by a multi model diagnosis method. Applying four algorithms, six models were established for diagnosis and tested by leave one out cross validation method. The model by artificial neural network (ANN) was selected as the best model to analyze breath samples. 89 clinical samples were tested with MOS SAW ANN diagnostic model, which takes the features derived from both the MOS and SAW sensors. It shows the highest sensitivity of 93.62% and the highest selectivity o.", "author_names": [ "Di Wang", "Kai Yu", "Yishan Wang", "Yan-jie Hu", "Cong Zhao", "Lin Wang", "Kejing Ying", "Ping Wang" ], "corpus_id": 94527296, "doc_id": "94527296", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "A HYBRID ELECTRONIC NOSES' SYSTEM BASED ON MOS SAW DETECTION UNITS INTENDED FOR LUNG CANCER DIAGNOSIS", "venue": "", "year": 2012 }, { "abstract": "In this paper our three recent achievements of electronic noses are reviewed with the emphasis on Artificial Neural Networks (ANNs) The back propagation algorithm has been used for identifying aromas of alcoholic beverages, and Fuzzy Learning Vector Quantization algorithm has been developed and is found promising for odour discrimination. The third is the analog ANN hardware which can be used in a compact odour sensing system. Those algorithms and a hardware system are discussed with respects to odour or gas identification capability.", "author_names": [ "Toyosaka Moriizumi", "Takamichi Nakamoto", "Yuichi Sakuraba" ], "corpus_id": 60935019, "doc_id": "60935019", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Pattern Recognition in Electronic Noses by Artificial Neural Network Models", "venue": "", "year": 1992 }, { "abstract": "This work studies the changes along days of the aroma released from a flavour encapsulated in a polysaccharide gel matrix using the electronic nose methodology. The purpose is to explore the capacity of the sensor array to assign a pattern of aroma to the corresponding release day within a total period of five days. Different procedures of data treatment and analysis are compared in order to achieve the maximum of information of the system under study in conditions where the number of measurements is limited. Raw and normalized sensor signals are processed using various unsupervised and supervised data analysis algorithms such as Principal Component Analysis, Kohonen Self Organizing Maps, Cluster Analysis, Multiple Discriminant Analysis and two types of Artificial Neural Networks (BP ANN and RBF ANN) Accurate assignation of the number of release days is obtained with a successful classification up to four classes associated to samples at increasing days of aroma release. The relative advantages and drawbacks of the different procedures and data manipulations are discussed.", "author_names": [ "Silvio D Rodriguez", "Maria Eugenia Monge", "Alejandro Cesar Olivieri", "R Martin Negri", "Delia L Bernik" ], "corpus_id": 97452650, "doc_id": "97452650", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "Time dependence of the aroma pattern emitted by an encapsulated essence studied by means of electronic noses and chemometric analysis", "venue": "", "year": 2010 }, { "abstract": "Abstract Background An e nose or an e tongue is a group of gas sensors or chemical sensors that simulate human nose or human tongue. Both e nose and e tongue have shown great promise and utility in improving assessments of food quality characteristics compared with traditional detection methods. Scope and approach This review summarizes the application of e nose and e tongue in determining the quality related properties of foods. The working principles, applications, and limitations of the sensors employed by electronic noses and electronic tongues were introduced and compared. Widely employed pattern recognition algorithms, including artificial neural network (ANN) convolutional neural network (CNN) principal component analysis (PCA) partial least square regression (PLS) and support vector machine (SVM) were introduced and compared in this review. Key findings and conclusions Overall, e nose or e tongue combining pattern recognition algorithms are very powerful analytical tools, which are relatively low cost, rapid, and accurate. E nose and e tongue are also suitable for both in line and off line measurements, which are very useful in monitoring food processing and detecting the end product quality. The user of e nose and e tongue need to strictly control sample preparation, sampling, and data processing.", "author_names": [ "Juzhong Tan", "Jie Xu" ], "corpus_id": 226646045, "doc_id": "226646045", "n_citations": 40, "n_key_citations": 1, "score": 0, "title": "Applications of electronic nose (e nose) and electronic tongue (e tongue) in food quality related properties determination: A review", "venue": "", "year": 2020 }, { "abstract": "Abstract This paper reports a quantitative artificial neural network (ANN) to implement an electronic nose (enose) A new approach was proposed by the combination of ANN with fundamental aspects of analytical chemistry, especially with the concept of relative error (RE) in quantitative analysis. Thus, both the qualitative and quantitative requirements for ANN in implementing enose can be satisfied. Converging criterion while training the ANN can be set according to RE function (RE Func) designed in this work. Fast converging speed and good prediction accuracy could be promised with the use of RE Func. In addition, transform functions in logarithmic, sigmoid and their combined forms to pre process training data sets were evaluated. Also training methods, such as order of training data magnitude and treatment of data passed the RE requirement checking in last iteration, were optimized. The enose was constructed to response quantitatively towards alcohol vapor within concentration range of 0.001 1 mg/l in the presence of petroleum gas and water vapor. The prediction error was", "author_names": [ "Yu Lu", "Li-Fang Bian", "Pengyuan Yang" ], "corpus_id": 95195289, "doc_id": "95195289", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Quantitative artificial neural network for electronic noses", "venue": "", "year": 2000 }, { "abstract": "Abstract An electronic nose device developed in our laboratory was used to follow the flavour release of a multi component essence encapsulated in pectin gels. Gelation kinetics of high methoxylated pectin was followed by dynamic rheological measurements in presence and absence of flavour. A transition from a non stabilized structure to a fully stabilized gel was observed at about 100 min since mixing the gel components. Flavour release through different days after encapsulation was analyzed following the time evolution of the individual gas sensor's signals of the e nose and also the modification of the fingerprints associated to the whole response of the sensors array. The correlation with rheological measurements indicate that the e nose is able to detect the gel formation and to follow the flavour release changes through aging of the material using principal component analysis (PCA) Artificial neural networks (ANN) analysis was also a successful approach to classify the samples in three categories related with the flavour composition and concentration in the gas phase.", "author_names": [ "Maria Eugenia Monge", "Donatella Bulone", "Daniela Giacomazza", "Delia L Bernik", "R Martin Negri" ], "corpus_id": 98695603, "doc_id": "98695603", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Detection of flavour release from pectin gels using electronic noses", "venue": "", "year": 2004 }, { "abstract": "In this study we propose a practical approach to increase the performance of electronic noses (E noses) in cigarette brand identification. A portable E nose was employed to collect and classify aroma signals from different brands of cigarettes. Artificial neural networks (ANN) were employed and trained with raw data and extracted features from the data collected by the E nose to identify the cigarettes. The Chinese cigarette industry is losing millions of dollars per year due to counterfeit cigarettes. Detecting illegal cigarettes in the field is difficult, but may be possible using portable E noses. However, the differences between odours from counterfeit and genuine cigarettes are small and detection may prove difficult. This preliminary investigation succeeded in identifying four different types of cigarettes in the laboratory. The identification results obtained from the intelligent E noise trained with an ANN using the extracted parameters were better than the ones obtained directly from the E nose.", "author_names": [ "Dehan Luo" ], "corpus_id": 164209303, "doc_id": "164209303", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Cigarette Brand Identification Using Intelligent Electronic Noses", "venue": "", "year": 2003 }, { "abstract": "The present paper covers a new type of electronic nose (e nose) with a four sensor array, which has been applied to detecting gases quantitatively in the presence of interference. This e nose has adapted fundamental aspects of relative error (RE) in changing quantitative analysis into the artificial neural network (ANN) Thus, both the quantitative and the qualitative requirements for ANN in implementing e nose can be satisfied. In addition, the e nose uses only 4 sensors in the sensor array, and can be designed for different usages simply by changing one or two sensor(s) Various gases were tested by this kind of e nose, including alcohol vapor, CO, iiquefied petrol gas and CO2. Satisfactory quantitative results were obtained and no qualitative mistake in prediction was observed for the samples being mixed with interference gases.", "author_names": [ "" ], "corpus_id": 106499379, "doc_id": "106499379", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Electronic Noses Using Quantitative Artificial Neural Network", "venue": "", "year": 2001 }, { "abstract": "Electronic nose (e nose) devices have received considerable attention in the field of sensor technology because of their many potential uses such as in identification of toxic wastes, monitoring air quality, examining odors in infected wounds and in inspection of food. Notwithstanding the vast amount of literature on the usage of e noses for specific purposes, the technology originally and ultimately aims to mimic the capability of mammals to discriminate odors from all sorts of objects. This study demonstrates the theoretical and practical feasibility of designing an e nose towards general odor classification. A multi sensor array hardware unit was carefully constructed for data collection and odor detection. Important hardware design considerations such as sensor calibration, aeration, circuit protection, and voltage/current requirements were satisfied. A highly fine tuned artificial neural network (ANN) was integrated to the hardware to interpret and relate the data to a target odor class from a set of 10 primary odors identified in a previous study. Various network architecture considerations, such as neuron count, number of layers and activation function, as well as various data treatment methods, such as normalization, and data partitioning, were investigated. The results showed that careful hardware integration with an ANN having sufficiently deep internal structure can yield accurate classification to at least half of the ten primary odor classes, namely fragrant (96% fruity (98% chemical (99% peppermint (98% and popcorn (90% The results demonstrate the feasibility of making e noses for general odor classification, which could lead to further broadening of e nose applications.", "author_names": [ "Marylin Roa", "Proceso L Fernandez" ], "corpus_id": 69821280, "doc_id": "69821280", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Development of an Electronic Nose for Olfactory System Modelling using Artificial Neural Network", "venue": "", "year": 2018 } ]

[ { "abstract": "Time resolved photoluminescence (TRPL) spectroscopy is a powerful technique to investigate excited charge carrier recombinations in semiconductors and molecular systems. The analysis of the TRPL decays of many molecular systems (e.g. molecules and organic materials) is usually fairly straightfoward and can be fitted with an exponential function allowing extraction of the rate constants. Due to the non excitonic nature of charge carriers in lead halide perovskite materials coupled with the presence of localised trap states in their band gap, the TRPL of these materials is much more complicated to interpret. Here we discuss two models used in the literature to simulate charge carrier recombinations and TRPL in perovskites. These models consider the bimolecular nature of direct electron hole recombination but differ in their treatment of trap mediated recombination with one model describing trapping as a monomolecular process whereas the other as a bimolecular process between free carriers and the available trap states. In comparison, the classical analysis of perovskite TRPL decay curves (using a sum of exponentials) can lead to misinterpretation. Here we offer some recommendations for meaningful measurements of lead halide perovskite thin films. The fluence dependence as well as charge carrier accumulation due to incomplete depopulation of all photoexcited carriers between consecutive excitation pulses are discussed for both models.", "author_names": [ "Emmanuel V Pean", "Stoichko D Dimitrov", "Catherine S P De Castro", "Matthew L Davies" ], "corpus_id": 228088476, "doc_id": "228088476", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Interpreting time resolved photoluminescence of perovskite materials.", "venue": "Physical chemistry chemical physics PCCP", "year": 2020 }, { "abstract": "The diffusion length of photogenerated carriers is a crucial parameter in semiconductors for optoelectronic applications. However, it is a challenging task to determine the diffusion length in layered nanoplatelets due to their anisotropic diffusion of photogenerated carriers and nanometer thin thickness. Here, we demonstrate a novel method to determine the in plane diffusion length of photogenerated carriers in layered nanoplatelets using local time resolved photoluminescence. An in plane carrier diffusion length of 1.82 um is obtained for an exfoliated (BA)2PbI4 (BA=CH3(CH2)3NH3) perovskite nanoplatelet. This method is particularly useful for weak luminescent materials and the materials that are easily damaged by long term laser beam because of the high detection sensitivity. This technique is extendable to other layered materials and therefore plays a valuable role in the development and optimization of 2D and 3D semiconductor materials and devices for photovoltaic and photonic applications.", "author_names": [ "Chunhua Zhou", "Weijian Chen", "Shuang Yang", "Qingdong Ou", "Zhixing Gan", "Qiaoliang Bao", "Baohua Jia", "Xiaoming Wen" ], "corpus_id": 218618349, "doc_id": "218618349", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Determining in plane Carrier Diffusion in Two Dimensional Perovskite using local time resolved photoluminescence.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "Halide perovskite photovoltaic cells have attracted tremendous attention over recent years due to the rapid rise in solar cell efficiencies and their potential for providing high efficiency low cost solar power.1 Solar cell efficiencies have increased from 9% in 2012 to 21% in 2017 and are now competitive with traditional crystalline silicon cells.2,3 Despite this impressive rise in efficiency, the fundamental physics of these materials is not yet fully understood. In this application note time resolved photoluminescence spectroscopy will be shown to be a powerful tool for investigating and optimising the behaviour of perovskite through the measurement of charge carrier lifetimes. Introduction", "author_names": [], "corpus_id": 195799963, "doc_id": "195799963", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Measuring Charge Carrier Lifetime in Halide Perovskite Using Time Resolved Photoluminescence Spectroscopy", "venue": "", "year": 2018 }, { "abstract": "Abstract We present the localization effects in orthorhombic phase of CH3NH3PbI3 perovskite materials by temperature dependent photoluminescence and time resolved photoluminescence. Our investigations indicate that the tetragonal inclusions in the orthorhombic phase of MAPbI3 at low temperature are the main reason for the formation of localization states with a depth of about 22.3 meV. The coexistence of the tetragonal and orthorhombic phases also results in an abnormal behavior of luminescence intensity from 12 to 80 K. The detailed understanding of luminescence characteristics upon the orthorhombic phase in MAPbI3 at low temperature can expand ideally the application fields of perovskite materials.", "author_names": [ "Fu Jen Cheng", "S Y Hu", "L Y Chen", "Y C Lee", "Gerald Zheyao Yin", "K K Tiong", "J L Shen" ], "corpus_id": 103405360, "doc_id": "103405360", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Time resolved photoluminescence studies on localization effects in orthorhombic phase of CH3NH3PbI3 perovskite thin film", "venue": "", "year": 2018 }, { "abstract": "Carrier lifetime characterization in solar cell and light emitting diode materials by time resolved photoluminescence and differential transmission is of high importance, indicating cost efficient streak camera suitable for such tests would be highly demanded. In this work an electro optic deflecting device is extended to full functionality streak camera operating in wide spectral range (200 2000 nm) by using electro optic DKDP crystals. Setup, consisting of picosecond laser for sample excitation, electro optic deflector and imaging spectrograph with silicon and InGaAs cameras, allows spectral and temporal imaging of recombination dynamics in semiconductor materials, with variable bandgap and composition (tested on metal halide perovskite crystal) achieving temporal resolution up to 50 ps. For the case of time resolved differential transmission, broadband <50 ps pulsed or CW xenon light source can be used for absorption change probing.", "author_names": [ "Patrik Scajev" ], "corpus_id": 233831941, "doc_id": "233831941", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Time resolved photoluminescence and xenon differential transmission measurement device based on electro optic deflector", "venue": "OPTO", "year": 2021 }, { "abstract": "A self powered,solution processed perovskite photodetector with sub nanosecond response time is presented. Eliminating charge trapping and removing the constraints from the resistance capacitance constant increases the response speed, which enables them to be applied in a homemade, time resolved photoluminescence system that successfully resolves the decay process of typical fluorescence and phosphorescent materials with a recombination lifetime from several nanoseconds to microseconds.", "author_names": [ "Liang Shen", "Yanjun Fang", "Dong Wang", "Yang Bai", "Yehao Deng", "Mengmeng Wang", "Yongfeng Lu", "Jinsong Huang" ], "corpus_id": 35623878, "doc_id": "35623878", "n_citations": 174, "n_key_citations": 0, "score": 0, "title": "A Self Powered, Sub nanosecond Response Solution Processed Hybrid Perovskite Photodetector for Time Resolved Photoluminescence Lifetime Detection.", "venue": "Advanced materials", "year": 2016 }, { "abstract": "In the quest for better solar panels, we continue to refine our understanding of the physics of photovoltaic absorbers, such as hybrid metal organic perovskites. By scrutinizing photoluminescence transients, the authors explain how to determine fundamental semiconductor properties and estimate the potential open circuit voltage of perovskite thin films. Additionally, they highlight the impacts of photon recycling, doping, and bulk and surface recombination of charge carriers on device performance.", "author_names": [ "Florian Staub", "Hannes Hempel", "Jan-Christoph Hebig", "J B Mock", "Ulrich Wilhelm Paetzold", "Uwe Rau", "Thomas Unold", "Thomas Kirchartz" ], "corpus_id": 53411239, "doc_id": "53411239", "n_citations": 116, "n_key_citations": 1, "score": 0, "title": "Beyond Bulk Lifetimes: Insights into Lead Halide Perovskite Films from Time Resolved Photoluminescence", "venue": "", "year": 2016 }, { "abstract": "Owing to their exceptional semiconducting properties, hybrid inorganic organic perovskites show great promise as photovoltaic absorbers. In these materials, long range diffusion of charge carriers allows for most of the photogenerated carriers to contribute to the photovoltaic efficiency. Here, time resolved photoluminescence (PL) microscopy is used to directly probe ambipolar carrier diffusion and recombination kinetics in hybrid perovskites. This technique is applied to thin films of methylammonium lead tri iodide MAPbI$_3$ obtained with two different fabrication routes, methylammonium lead tribromide (MAPbBr$_3$ and an alloy of formamidinium lead tri iodide (FAPbI$_3$ and methylammonium lead bromide FA$_{0.85}$MA$_{0.15}$Pb(I$_{0.85}$Br_${0.15}$_3$ Average diffusion coefficients in the films leading to the highest device efficiencies and longest lifetimes, i.e. in FA$_{0.85}$MA$_{0.15}$Pb(I$_{0.85}$Br$_{0.15}$_3$ and acetonitrile processed MAPbI$_3$ are found to be several orders of magnitude lower than in the other films. Further examination of the time dependence shows strong evidence for non diffusive transport. In particular, acetonitrile processed MAPbI$_3$ shows distinct diffusion regimes on short and long timescales with an effective diffusion constant varying over 2 orders of magnitude. Our results also highlight the fact that increases in carrier lifetime in this class of materials are not necessarily concomitant with increased diffusion lengths and that the PL quantum efficiency under solar cell operating conditions is a greater indication of material, and ultimately device, quality.", "author_names": [ "Aravindan Sridharan", "Nakita K Noel", "Hyeon Jun Hwang", "Soroush Hafezian", "Barry P Rand", "St'ephane K'ena-Cohen" ], "corpus_id": 166227918, "doc_id": "166227918", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Time resolved imaging of non diffusive carrier transport in long lifetime halide perovskite thin films.", "venue": "", "year": 2019 }, { "abstract": "Organic inorganic halide perovskite solar cells are attracting much attention from the photovoltaic community because of their high conversion efficiencies exceeding 20% So far, intrinsic superior optoelectronic properties of this material class have been revealed through comprehensive studies on the thin films and single crystals [1,2] For further improvement of the device architecture and conversion efficiency, the carrier recombination and transport dynamics in actual solar cell devices have to be clarified. The perovskite solar cell is usually implemented as a heterojunction structure consisting of a perovskite absorber layer and charge transport layers as selective contacts, and the carrier injection properties at these heterointerfaces play a crucial role for the device performance. Time resolved photoluminescence (PL) techniques are usually adopted to investigate carrier injection and transport properties [3] However, PL is also additionally affected by traps and defects within the perovskite layer and also at the heterointerface. On the other hand, the photocurrent (PC) measurement can directly assess the net charge carrier flow through the whole device. Therefore a combination of PL and PC enables us to investigate the details of the carrier injection. In addition, perovskite solar cells are prepared by a fast and cost effective low temperature solution process, but this simple preparation method also causes a spatial nonuniformity in the optical and electrical properties [4] Thus, the spatial imaging is invaluable for statistical evaluation of the solar cell characteristics.", "author_names": [ "Taketo Handa", "Daiki Yamashita", "David M Tex", "Ai Shimazaki", "Atsushi Wakamiya", "Yoshihiko Kanemitsu" ], "corpus_id": 23558240, "doc_id": "23558240", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Charge carrier injection at the heterointerface in CH3NH3PbI3 perovskite solar cells studied by time resolved photoluminescence and photocurrent imaging spectroscopy", "venue": "2017 Conference on Lasers and Electro Optics Europe European Quantum Electronics Conference (CLEO/Europe EQEC)", "year": 2017 }, { "abstract": "While perovskite nanocrystals (NCs) have shown great promise as materials for efficient light emitting diodes (LEDs) low photoluminescence quantum yield (PLQY) of the blue emitting perovskites is an impediment to the development of white LEDs of which blue is an essential component. Herein, we report that room temperature postsynthetic treatment of weakly blue violet emitting (PLQY 3% CsPbCl3 NCs with CdCl2 results in an instantaneous enhancement of the PLQY to near unity without affecting the PL peak position (406 nm) and spectral width. The time resolved PL and ultrafast transient absorption measurements confirm the removal of nonradiative defect states of the CsPbCl3 NCs in treated sample. The elemental composition and structural data of the treated sample reveal facile doping of Cd2+ into the crystal lattice without affecting the size and shape of the NCs. Extraordinary PLQY, high air stability and photostability and ease of preparation of this Cd doped CsPbCl3 make it by far the most attractive blu.", "author_names": [ "Navendu Mondal", "Apurba De", "Anunay Samanta" ], "corpus_id": 139690255, "doc_id": "139690255", "n_citations": 162, "n_key_citations": 0, "score": 0, "title": "Achieving Near Unity Photoluminescence Efficiency for Blue Violet Emitting Perovskite Nanocrystals", "venue": "", "year": 2019 } ]

[ { "abstract": "Two dimensional semiconductor materials have shown strong non linear optical properties at the monolayer limit due to the lack of inversion symmetry. These non linear materials can ideally be combined with top down planar fabrication methods to offer new optical devices that can be integrated on chip as compared to large bulk non linear crystals. Here, we show enhanced second harmonic generation (SHG) from monolayer MoS2 embedded within an all dielectric Fabry Perot microcavity that is resonant at the pump wavelength. Power dependency shows a 10 fold increase in second harmonic generation matching theoretical estimate.", "author_names": [ "Jared K Day", "M Chung", "Yi-Hsien Lee", "Vinod M Menon" ], "corpus_id": 124607562, "doc_id": "124607562", "n_citations": 36, "n_key_citations": 0, "score": 0, "title": "Microcavity enhanced second harmonic generation in 2D MoS_2", "venue": "", "year": 2016 }, { "abstract": "Second harmonic generation (SHG) of two dimensional (2D) layered materials has attracted immense research interests due to the abilities of photon generation, manipulation, transmission, detection, and imaging for the applications of modern on chip nanophotonic devices. Some layered materials with broken inversion symmetry associated with their 2D nature enable the development of nanophotonic and nanooptoelectronic devices based on the second harmonic generation effect. Recently, many 2D materials with broken inversion symmetry have been discovered, which not only exhibit SHG quantum effects but also greatly promote the development of nanophotonics. In this review, we review the recent developments of all 2D SHG materials, including the graphene like family, transition metal dichalcogenides (TMDs) IIIA VIA compounds and others. We focus on their fabrication, structural characteristics, and generating mechanism and basic characteristics of SHG, associated with the main strategies to tune, modulate, and enhance the SHG of 2D materials. Additionally, several practical applications and possible future research directions of 2D material based SHG are discussed.", "author_names": [ "Jiantian Zhang", "Weina Zhao", "Peng Yu", "Guowei Yang", "Zixun Liu" ], "corpus_id": 225350666, "doc_id": "225350666", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Second harmonic generation in 2D layered materials", "venue": "", "year": 2020 }, { "abstract": "The Rashba effect (RE) caused by concurrent spin orbit coupling and structural inversion asymmetry (SIA) has been invoked to explain outstanding optoelectronic properties of hybrid organic inorganic perovskites (HOIPs) The SIA in HOIPs also manifests itself in second harmonic generation (SHG) Here, we establish a quantitative relation between the RE strength and the low frequency SHG value in two dimensional (2D) and three dimensional (3D) HOIPs using a newly developed effective mass model. The calculated SHG, which exhibits one and two photon resonances between the valence and conduction bands, approaches a finite value at low frequencies. Using the measured SHG values in literature, the estimated RE strength is 10 3 eV A for 3D CH3NH3PbI3 and 4 x 10 2 eV A for 2D (C4H9NH3)2PbI4. Our results facilitate a simple and reliable determination of the RE strengths of 2D and 3D HOIPs and help quantify the impact of RE on various properties in HOIPs.", "author_names": [ "Zhi-Gang Yu" ], "corpus_id": 104300130, "doc_id": "104300130", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Estimation of the Rashba Strength from Second Harmonic Generation in 2D and 3D Hybrid Organic Inorganic Perovskites", "venue": "", "year": 2018 }, { "abstract": "Second harmonic generation (SHG) from a monolayer MoS2 is enhanced by embedding within an all dielectric microcavity resonant at the pump wavelength. Power dependency shows a 10 fold increase in SH emission matching theoretical estimate.", "author_names": [ "Jared K Day", "Yi-Hsien Lee", "Vinod M Menon" ], "corpus_id": 19615899, "doc_id": "19615899", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Microcavity enhanced second harmonic generation in 2D semiconductors", "venue": "2016 Conference on Lasers and Electro Optics (CLEO)", "year": 2016 }, { "abstract": "Theoretical analysis is given to second harmonic generation in 2D nonlinear photonic crystals of rectangular symmetry with rectangular domains. Formulas for the nonlinear response of the crystal with an arbitrary domain structure are derived within the approximation of a given field. A possibility of calculating time profiles of second harmonic pulses down to the femtosecond range is demonstrated.", "author_names": [ "B E Eshniezov", "Bakhodir Eshchanov", "Djavdat B Yusupov", "Kakhramon Ergashov", "Usman K Sapaev" ], "corpus_id": 126353947, "doc_id": "126353947", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "On the theory of second harmonic generation in 2D nonlinear photonic crystals with arbitrary domain structures", "venue": "", "year": 2016 }, { "abstract": "and Magnetic Fields A.L. Morales, M.E. Mora Ramos and C.A. Duque Grupo de Materia Condensada UdeA, Instituto de Fisica, Facultad de Ciencias Exactas y Naturales Universidad de Antioquia UdeA, Calle 70 No. 52 21, Medellin, Colombia Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Cuernavaca, Mexico Fisica Teorica y Aplicada, Escuela de Ingenieria de Antioquia, Envigado, Antioquia, Colombia", "author_names": [ "Alvaro Luis Morales", "Miguel E Mora-Ramos", "C A Duque" ], "corpus_id": 119915988, "doc_id": "119915988", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Nonlinear Optical Rectification and Second Harmonic Generation in 2D Quantum Rings under Electric Field and Magnetic Fields", "venue": "", "year": 2014 }, { "abstract": "Two dimensional (2D) materials have brought a spectacular revolution in fundamental research and industrial applications due to their unique physical properties of atomically thin thickness, strong light matter interaction, unity valley polarization and enhanced many body interactions. To fully explore their exotic physical properties and facilitate potential applications in electronics and optoelectronics, an effective and versatile characterization method is highly demanded. Among the many methods of characterization, optical second harmonic generation (SHG) has attracted broad attention because of its sensitivity, versatility and simplicity. The SHG technique is sufficiently sensitive at the atomic scale and therefore suitable for studies on 2D materials. More importantly, it has the capacity to acquire abundant information ranging from crystallographic, and electronic, to magnetic properties in various 2D materials due to its sensitivity to both spatial inversion symmetry and time reversal symmetry. These advantages accompanied by its characteristics of non invasion and high throughput make SHG a powerful tool for 2D materials. This review summarizes recent experimental developments of SHG applications in 2D materials and also provides an outlook of potential prospects based on SHG.", "author_names": [ "Dingxin Zou", "Muhong Wu" ], "corpus_id": 226314381, "doc_id": "226314381", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Rich information on 2D materials revealed by optical second harmonic generation.", "venue": "Nanoscale", "year": 2020 }, { "abstract": "Abstract Photonic crystal waveguides (PCW) have shown great potential to generate second harmonic (SH) but the available schemes with cavity or defect suffer from a lack of multiple wavelengths operation and excessive phase matching requirement. Here we propose a 2D PCW structure comprised of a modulated single line defect, which is capable of independently controlling the fundamental frequency (FF) and SH modes. Therefore, two near flat group velocity dispersions can be achieved for these modes, and they simultaneously satisfy phase matching conditions. Based on multiply scattering method, we theoretically demonstrate that the SH resonant modes originated from the nonradiative near flat dispersion have high quality factors (nearly 6 5 x 1 0 4 for the maximum value) And the maximum SH conversion efficiency for these resonant modes are 2 orders of magnitude higher than that of off resonant modes. In addition, benefitting from the matching of the group velocities of the second harmonic and the fundamental, the central wavelength of SH can be modulated within wavelength range 3nm. These results can provide potential applications in on chip integration of photonics and quantum optics.", "author_names": [ "Jia-bin Zhang", "Hai Lu", "Kesheng Shen", "Hongchao Liu", "Yun Zheng", "Xiaolong Zhang" ], "corpus_id": 216353288, "doc_id": "216353288", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Second harmonic generation from 2D photonic crystal waveguide with simultaneous near flat dispersions at fundamental frequency and second harmonic", "venue": "", "year": 2020 }, { "abstract": "Optical second harmonic generation in strained two dimensional semiconductors and electroluminescence from multi particle exciton complexes in these materials will be discussed.", "author_names": [ "T Mueller", "Lukas Mennel", "Matthias Paur", "Aday J Molina-Mendoza" ], "corpus_id": 201319463, "doc_id": "201319463", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Second Harmonic Generation and Electroluminescence in 2D Semiconductors", "venue": "", "year": 2019 }, { "abstract": "We investigate two photon transitions to the electron hole scattering continuum in monolayer transition metal dichalcogenides, and identify two contributions to this nonlinear optical process with opposite circularly polarized valley selection rules. In the non interacting limit, the competition between the two contributions leads to a crossover of the selection rule with the increase of the two photon energy. With the strong Coulomb interaction between the electron and hole, the two contributions excite electron hole scattering states in orthogonal angular momentum channels, while the strength of the transition can be substantially enhanced by the interaction. Based on this picture of the two photon transition, the second harmonic generation (SHG) in the electron hole continuum is analyzed, where the Coulomb interaction is shown to greatly alter the relative strength of different cross circular polarized SHG processes. Valley current injection by the quantum interference of one photon and two photon transition is also investigated in the presence of the strong Coulomb interaction, which significantly enhances the injection rate.", "author_names": [ "Pu Gong", "Hongyi Yu", "Yong Wang", "Wang Yao" ], "corpus_id": 84181923, "doc_id": "84181923", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Nonlinear optics in the electron hole continuum in 2D semiconductors: two photon transition, second harmonic generation and valley current injection", "venue": "Science Bulletin", "year": 2019 } ]

[ { "abstract": "Part I of this three part series described semiconductor supply chains from the decision making and functional perspectives, using this as a framework to review the industrial engineering (IE) and operations research (OR) literature on the problems arising in these supply chains. Part I then reviewed the literature on Strategic Network Design, Supply Chain Coordination, Sustainability and Semiconductor Supply Chain Simulation, while Part II reviewed Demand Planning, Inventory Management, and Capacity Planning. This paper concludes the series, discussing Master Planning, Production Planning, Demand Fulfilment, and Available to Promise (ATP) in semiconductor supply chains.", "author_names": [ "Lars Monch", "Reha Uzsoy", "John W Fowler" ], "corpus_id": 117537470, "doc_id": "117537470", "n_citations": 29, "n_key_citations": 2, "score": 0, "title": "A survey of semiconductor supply chain models part III: master planning, production planning, and demand fulfilment", "venue": "Int. J. Prod. Res.", "year": 2018 }, { "abstract": "Part I of this three part series described semiconductor supply chains from the decision making and functional perspectives, using this as a framework to review the industrial engineering and operations research literature on the problems arising in these supply chains. Part I then reviewed the literature on Strategic Network Design, supply chain coordination, sustainability and simulation based decision support. This paper, Part II, reviews the areas of Demand Planning, Inventory Management and Capacity Planning in semiconductor supply chains. Part III concludes the series by discussing models to support Master Planning, Production Planning and Demand Fulfilment in this industry.", "author_names": [ "Reha Uzsoy", "John W Fowler", "Lars Monch" ], "corpus_id": 116451723, "doc_id": "116451723", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "A survey of semiconductor supply chain models Part II: demand planning, inventory management, and capacity planning", "venue": "Int. J. Prod. Res.", "year": 2018 }, { "abstract": "Abstract Model Based System Engineering (MBSE) is an increasingly important methodology to support system engineering and has attained a high level of attentiveness in business simulation practices as a conceptual modelling approach. In this paper, we present our results related to the application of MBSE approaches in complex semiconductor manufacturing supply chain planning systems. We investigate System Modeling Language (SysML) Web Ontology Language (OWL) and Business Process Modeling Notation (BPMN) as different approaches and languages for MBSE. These approaches are surveyed and used to develop conceptual models for the simulation of the order management process inside the supply chain management. This study aims to survey and offer a number of implications for MBSE practice and seeks to stimulate and guide further research in this area.", "author_names": [ "Behrouz Alizadeh Mousavi", "Radhia Azzouz", "Cathal Heavey", "Hans Ehm" ], "corpus_id": 212904726, "doc_id": "212904726", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A Survey of Model Based System Engineering Methods to Analyse Complex Supply Chains: A Case Study in Semiconductor Supply Chain", "venue": "", "year": 2019 }, { "abstract": "Moore's Law indicates that the amount of transistors which can be accommodated on integrated circuit (IC) double every two years in semiconductor manufacturing industry. As a capital intensive and competitive industry, supply chains in the semiconductor industry feature high structural complexity and high demand uncertainty. In order to enhance the effectiveness of the enterprise, total resource management (TRM) for semiconductor industry is increasingly crucial. Past studies focused on measuring the effectiveness of either demand fulfillment or capacity utilization, but little researches have done for investigating the inter coordination on both aspects. This paper proposes overall supply chain effectiveness (OSCE) for the incorporation of demand planning and capacity portfolio based on PDCCCR framework to evaluate the effectiveness of semiconductor supply chain industry. The proposed index is implemented in an empirical study based on a simulation model for semiconductor backend production. Finally, the paper concludes with the discussion of future research directions.", "author_names": [ "Hsuan An Kuo", "Thomas Ponsignon", "Hans Ehm", "Chen Fu Chien" ], "corpus_id": 210930154, "doc_id": "210930154", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Overall Supply Chain Effectiveness (OSCE) for Demand and Capacity Incorporation in Semiconductor Supply Chain Industry", "venue": "2019 IEEE International Conference on Smart Manufacturing, Industrial Logistics Engineering (SMILE)", "year": 2019 }, { "abstract": "Supply chain collaboration is the prerequisite for successful procurement and operational business practices for short life cycled products, especially due to competitive marketplace, and globalization, which necessitates the requirement of most appropriate planning frameworks. Supply chain planning in the semiconductor industry integrates the complex network of wafer foundries, probe and assembly manufacturing sites together to enhance operational effectiveness. So, the supply chain planning system should aggregate data from multiple sources to provide visibility and interoperable collaboration to an extended network of stakeholders. While exploring buyer supplier collaborative relationships and new procurement opportunities, the present work proposes a framework for depicting an appropriate policy. The following aspects of the supply chain are explored while developing such a framework: (1) business planning, (2) supply management, (3) demand management, (4) multi echelon inventory optimization, (5) customer order fulfillment, and (6) transportation and logistics management. The novelty of this work lies in the simultaneous consideration of six interrelated perspectives of supply chain planning along with the perspective of collaboration among supply chain members on the basis of information sharing. The proposed framework captures the technological and business basis for integration of various elements for supply chain planning with expected outcomes.", "author_names": [ "Bikram K Bahinipati" ], "corpus_id": 168681887, "doc_id": "168681887", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "A Framework for Semiconductor Industry Supply Chain Planning: The Procurement Perspective", "venue": "", "year": 2010 }, { "abstract": "Abstract Where demand outstrips supply, there will result in shortages to end customers. In such a case decisions need to be made of how to allocate supply to customers. Customer satisfaction requires accurate order promising that leads to better cooperation, as well as trustable orders and forecasts from customers. As a result, customer satisfaction through a trustable promising system leads to more accurate planning for production. In this regard, modern Advanced Planning Systems (APS) provides allocation planning to customers' orders based on \"Available To Promise\" (ATP) Lack of supply, escalation, and excess demand are propelled by competitive plant capacity, dynamic behaviours of ATP, orders, and demand forecasts in demanding industries like semiconductor manufacturing. When demand exceeds supply, APS needs the support of experts (human intervention) about the time and amount to be allocated to customers. This feature of APS keeps the flexibility of planning to find feasible optimal decisions regarding allocations. In this paper, we propose a mathematical model for the optimization of ATP allocation to customers, where demand exceeds supply, which will be presented as a decision support tool to analyse allocation scenarios. The objective of the proposed mathematical model is maximizing customer service level which is directly related to customer satisfaction while keeping a maximum of stock. The model is being developed from a case study of a European semiconductor supply chain with a sales office in Ireland. In this case study, support will be provided to allocation managers that allows flexibility solutions to be developed. The obtained results have validated the proposed multi objective mathematical model.", "author_names": [ "Behrouz Alizadeh Mousavi", "Radhia Azzouz", "Cathal Heavey" ], "corpus_id": 213414032, "doc_id": "213414032", "n_citations": 2, "n_key_citations": 0, "score": 2, "title": "MATHEMATICAL MODELLING OF PRODUCTS ALLOCATION TO CUSTOMERS FOR SEMICONDUCTOR SUPPLY CHAIN", "venue": "", "year": 2019 }, { "abstract": "Semiconductor manufacturing is highly complex, invest intensive and constantly changing due to innovation. The semiconductor product market is highly volatile due to short product life cycles with difficult to predict ramps and end of life demands. These challenges are mitigated via flexible production capabilities, e.g. dynamic routing or rescheduling, used by planning systems to transfer volatile demands to well utilized factories. The product structure is one of the keys for enabling the desired result. Product structure representations include linear, tree, and network. In this paper, definitions of several product structure representations are given and hypothesized benefits and drawbacks are discussed. Research questions are posed, current research efforts are introduced, and the hypothesis that a time dependent network tree representation would be beneficial is postulated. The problem statement is explained by a real case merger where risk and opportunities based on the choice of product structure representation were relevant and no final solution was determined.", "author_names": [ "Hans Ehm", "Cedric Neau", "Christian James Martens", "Tim Lauer", "Thomas Ponsignon", "Joaquin Garcia" ], "corpus_id": 211244010, "doc_id": "211244010", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research Opportunities Regarding Tree and Network Productstructure Representations in a Semiconductor Supply Chain", "venue": "2019 Winter Simulation Conference (WSC)", "year": 2019 }, { "abstract": "Semiconductor manufacturing is highly complex, invest intensive and constantly changing due to innovation. The semiconductor product market is highly volatile due to short product life cycles with difficult to predict ramps and end of life demands. These challenges are mitigated via flexible production capabilities, e.g. dynamic routing or rescheduling, used by planning systems to transfer volatile demands to well utilized factories. The product structure is one of the keys for enabling the desired result. Product structure representations include linear, tree, and network. In this paper, definitions of several product structure representations are given and hypothesized benefits and drawbacks are discussed. Research questions are posed, current research efforts are introduced, and the hypothesis that a time dependent network tree representation would be beneficial is postulated. The problem statement is explained by a real case merger where risk and opportunities based on the choice of product structure representation were relevant and no final solution was determined.", "author_names": [ "Navonil Mustafee", "K -H G Bae", "Sanja Lazarova-Molnar", "Markus Rabe", "C Szabo", "Pol-Andre Haas", "Y-J Son" ], "corpus_id": 211528379, "doc_id": "211528379", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "OPPORTUNITIES REGARDING TREE AND NETWORK PRODUCT STRUCTURE REPRESENTATIONS IN A SEMICONDUCTOR SUPPLY CHAIN", "venue": "", "year": 2019 }, { "abstract": "Supply chain management issues have become increasingly important to the semiconductor industry over the last two decades due to the global distribution of facilities and increasing numbers of firms specialising in particular stages. This series of three papers reviews the literature on modelling and analysis of the larger semiconductor supply chain. After describing the structure of semiconductor supply chains to provide context for the research efforts, we propose a classification scheme for the relevant literature. The remainder of this paper (Part I) then focuses on Strategic Network Design models for this industry, supply chain coordination through contracting and semiconductor supply chain simulation. Part II discusses Demand Planning, Inventory Management and Capacity Planning, while Part III addresses Master Planning, Production Planning and Demand Fulfilment.", "author_names": [ "Lars Monch", "Reha Uzsoy", "John W Fowler" ], "corpus_id": 116300281, "doc_id": "116300281", "n_citations": 48, "n_key_citations": 5, "score": 0, "title": "A survey of semiconductor supply chain models part I: semiconductor supply chains, strategic network design, and supply chain simulation", "venue": "Int. J. Prod. Res.", "year": 2018 }, { "abstract": "In this paper, we propose a deterministic mixed integer programming model to schedule weekly production quantities for semiconductor manufacturing in order to meet forecasted demand over a six month planning horizon. The model considers facility capacities, facility qualifying, limits on the number of facilities to use, and unit level minimum inventory requirements. Model validity is demonstrated with a simple test case based on an industry dataset. A case study is then presented using actual industry data. Minimum inventory requirement levels are varied and compared to results obtained from traditional safety stock policies.", "author_names": [ "Jonathan J Lowe", "Scott J Mason" ], "corpus_id": 37810790, "doc_id": "37810790", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Integrated Semiconductor Supply Chain Production Planning", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2016 } ]

[ { "abstract": "Abstract In 2016, the NATO Science for Peace and Security Programme funded research project \"Engineering Silicon Carbide for Border and Port Security\" E SiCure was launched, its objective being the development of radiation hard silicon carbide (SiC) based detectors of special nuclear materials (SNM) with the aim to enhance border and port security barriers. Detector prototypes based on SiC Schottky Barrier Diodes (SBDs) and neutron converter films were developed. This paper presents the results of a dedicated experimental testing campaign performed at the Jozef Stefan Institute (JSI) TRIGA reactor in which several SiC detector prototypes equipped with 10 B and 6 LiF converter films were irradiated in the Dry Chamber of the reactor. The obtained results demonstrate a clearly measurable neutron response, which varies linearly with the neutron flux. The measured particle spectra from the SiC detectors exhibit a clear structure, attributable to the nature and energy of secondary particles originating as reaction products from nuclear reactions involving 10 B and 6 Li isotopes. The determined sensitivity of the detectors, their active volume being 1 mm x 1 mm x 25 m m 1 mm x 1 mm x 69 m m and 1 mm x 1 mm x 170 m m was of the order of 2 x 10 5 counts per second, per unit of neutron flux [counts s 1 per n cm 2s 1] (for neutron energies between 0 and 5 eV) Scaling the detection sensitivity by a factor of 1 0 5 i.e. to an array with a surface of around 20 cm x 2 m, comparable to large B F 3 or 3 He detectors, would theoretically enable an overall sensitivity of around 2 counts s 1 per n cm 2s 1, which is already comparable to typical neutron sensitivity values of gas detectors, in the range from several to over 100 counts s 1 per n cm 2s 1. Due to its outstanding tolerance to harsh environments (including high temperatures and radiation fields) and superior electronic properties when compared to other semiconductors, SiC is a promising base material for the fabrication of solid state detectors with stable and long life time. Improvements in sensitivity combined with the capability of fabricating large modules (SiC arrays) could make SiC an important detection technology, applicable also in the context of border and port security barrier monitoring.", "author_names": [ "V Radulovic", "Yuichi Yamazaki", "Zeljko Pastuovic", "Adam Sarbutt", "Klemen Ambrozic", "Robert Bernat", "Zoran Eres", "Jose Coutinho", "Takeshi Ohshima", "Ivana Capan", "Luka Snoj" ], "corpus_id": 218937765, "doc_id": "218937765", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Silicon carbide neutron detector testing at the JSI TRIGA reactor for enhanced border and port security", "venue": "", "year": 2020 }, { "abstract": "In 2016, the \"E SiCure\" project (standing for Engineering Silicon Carbide for Border and Port Security) funded by the NATO Science for Peace and Security Programme, was launched. The main objective is to combine theoretical, experimental and applied research towards the development of radiation hard SiC based detectors of special nuclear materials (SNM) and by that way, to enhance border and port security barriers. Along the plan, material modification processes are employed firstly to study, and secondly to manipulate the most severe electrically active defects (which trap or annihilate free charge carriers) by specific ion implantation and defect engineering. This paper gives an overview of the experimental activities performed at the JSI TRIGA reactor in the framework of the E SiCure project. Initial activities were aimed at obtaining information on the radiation hardness of SiC and at the study of the energy levels of the defects induced by neutron irradiation. Several Schottky barrier diodes were fabricated out of nitrogen doped epitaxial grown 4H SiC, and irradiated under Cd filters in the PT irradiation channel in the JSI TRIGA reactor with varying neutron fluence levels. Neutron induced defects in the material were studied using temperature dependent current voltage (I V) capacitance voltage (C V) and Deep Level Transient Spectroscopy (DLTS) measurements. Our prototype neutron detectors are configured as 4H SiC based Schottky barrier diodes for detection of secondary charged particles (tritons, alphas and lithium atoms) which are result of thermal neutron conversion process in 10 B and 6 LiF layers above the surface of the 4H SiC diodes. For field testing of neutron detectors using a broad beam of reactor neutrons we designed a standalone prototype detection system consisting of a preamplifier, shaping amplifier and a multichannel analyser operated by a laptop computer. The reverse bias for the detector diode and the power to electronic system are provided by a standalone battery powered voltage source. The detector functionality was established through measurements using an 241 Am alpha particle source. Two dedicated experimental campaigns were performed at the JSI TRIGA reactor. The registered pulse height spectra from the detectors, using both 10 B and 6 LiF neutron converting layers, clearly demonstrated the neutron detection abilities of the SiC detector prototypes.", "author_names": [ "V Radulovic", "Klemen Ambrozic", "Luka Snoj", "Ivana Capan", "Tomislav Brodar", "Zoran Eres", "Zeljko Pastuovic", "Adam Sarbutt", "Takeshi Ohshima", "Yuichi Yamazaki", "Jose Coutinho" ], "corpus_id": 213523238, "doc_id": "213523238", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "E SiCure Collaboration Project: Silicon Carbide Material Studies and Detector Prototype Testing at the JSI TRIGA Reactor", "venue": "", "year": 2020 }, { "abstract": "This article studies the convenience of implementing the Coast Floating Barrier System as a solution to the terrorism, a potential global threat that has the capacity to make attacks from the sea to the following targets (ships, harbors, port stations, etc..This system protects contacts, port facilities and coast stations from any attack from the sea, which consists on a physical containment barrier that provides perimeter security, preventing the entry of any vessel with explosives against a ship or coast station and which has been effectively tested in other countries around the world. For the research, we used the qualitative descriptive study with phenomenological design. Three dimensions had been analyzed: ideological, military and economic. To measure the results, we used the following elements: semi structured interviews, which resulted in the attention of containment and protection measures by the State and Navy of Peru against activities and attacks by national and international terrorism. The sampling was the police personnel with experience in the field of terrorism and naval personnel with experience in the field of maritime domain. For the investigation, interviews with experts were carried out as an instrument and the validity of the contents was made through the judgment of experts, whose responses were analyzed with the Binomial statistician method.", "author_names": [ "Jorge Chang Gamero" ], "corpus_id": 225647366, "doc_id": "225647366", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Barreras Flotantes De Costa, una Seguridad Fisica efectiva contra ataques terroristas provenientes del Mar", "venue": "", "year": 2020 }, { "abstract": "Port security is one of the most important fields of Vocational Education and Training (VET) maritime studies. In this article, we propose the configuration of entities that are used to design a port security information system for VET education. Our work integrates recent maritime Information Technology (IT) concepts into VET. We record the initial design for building educational software for a school level security information system that can be used as an extension project for the existing maritime curriculum of VET. This plan, if implemented and completed, will strengthen and expand the boundaries of school knowledge and curriculum. This article describes the design part of the whole project.", "author_names": [ "Apostolos Kaltsas", "Sofia Gompou", "Dimitrios Kotsifakos" ], "corpus_id": 213053014, "doc_id": "213053014", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Entity Configuration for Designing a Port Security Information System: Proposed Extensions of the Vocational Education and Training Curriculum", "venue": "", "year": 2020 }, { "abstract": "Ensuring maritime port security a rapidly increasing concern in a post 9/11 world presents certain operational challenges. As batteries and electric motors grow increasingly lighter and more powerful, unmanned aerial vehicles (UAVs) have been shown to be capable of enhancing a surveillance system's capabilities and mitigating its vulnerabilities. In this paper, we looked at the current role unmanned systems are playing in port security and proposed an image based method to enhance port security. The proposed method uses UAV real time videos to detect and identify humans via human body detection and facial recognition. Experiments evaluated the system in real time under differing environmental, daylight, and weather conditions. Three parameters were used to test feasibility: distance, height and angle. The findings suggest UAVs as an affordable, effective tool that may greatly enhance port safety and security.", "author_names": [ "Ruobing Zhao", "Zanbo Zhu", "Yueqing Li", "Jing Zhang", "Xiao Zhang" ], "corpus_id": 225592147, "doc_id": "225592147", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Use a UAV System to Enhance Port Security in Unconstrained Environment", "venue": "AHFE", "year": 2020 }, { "abstract": "Ports are organisationally complex critical infrastructures that have to deliver reliable movement of goods and the safe transport of people. The EU is concerned that there is an increasing number of cases where ports have been subject to combined attacks on their IT and physical infrastructure for criminal gain or other malign purposes. The European Commission has funded the SAURON project (Scalable multidimensionAl sitUation awaReness sOlution for protectiNg European ports) to help protect European ports from a physical, cyber or a combined cyber physical attack. The aim of this paper is to provide guidance on how port security needs to evolve to respond to the cyber physical security threat, drawing on concepts developed in SAURON. This paper reviews the current port security approaches and the cyber physical security threat and then assesses how new systems and technologies under development, including SAURON technologies, may help to reduce port vulnerabilities. For example, to detect combined attacks on port infrastructure in the physical and cyber domains and identify the cascading effects of an incident in both domains to enable effective countermeasures, the SAURON hybrid situational awareness tool incorporates inputs from the physical and cyber domains and analyses their interdependencies. The goal is that once a physical and/or cyber threat is detected, the potential consequences including cascading effects in both planes will be automatically shown to decision makers in order to give them integrated situational awareness of what is happening and how the situation could evolve, thus supporting decision making. The benefits of such approaches are described. Security technologies need to be complemented by effective security processes operated by personnel with appropriate training: the paper uses results of a table top exercise supported by analysis of port user requirements to identify the importance of multidisciplinary training in combatting complex combined cyber physical security threats.", "author_names": [ "N P H Adams", "R J Chisnall", "Chris Pickering", "Stefan Schauer" ], "corpus_id": 214220025, "doc_id": "214220025", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "How Port Security has to evolve to address the Cyber Physical Security Threat: lessons from the SAURON project", "venue": "", "year": 2020 }, { "abstract": "", "author_names": [ "Carl J Reinhardt" ], "corpus_id": 230598763, "doc_id": "230598763", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "7. Global Port Security", "venue": "", "year": 2020 }, { "abstract": "Abstract In this study, we used a 10 year (2007 2016) mark recapture dataset to investigate the potential effects of flooding and port development on the population dynamics of Australian humpback dolphins (Sousa sahulensis) inhabiting the Fitzroy River and Port Curtis, within the southern Great Barrier Reef region. A Multisite Capture Recapture model was used to quantify population size and demographic parameters for both sexes and sites. Flood occurrence and intensity (both sites) and port development (Port Curtis) were included as explanatory variables. Abundance estimates indicated that about 77 adult dolphins were present in both sites, of which 69% were females. Most females (69% were resident with a yearly recruitment close to zero for most years. Most males and unsexed (68% individuals showed little evidence of long term residency. The abundances of males and unsexed individuals varied between 15 and 20 dolphins in the Fitzroy River and 19 26 in Port Curtis, but the accuracy was too low to assess changes. Female abundances started at 56 in both sites and declined to about 32 per site in 2011, coinciding with port development construction activities and a concurrent major flood. In Port Curtis, the number of females returned to their original levels once the port development was completed in 2013. In the Fitzroy River, the declining trend continued and reached the lowest estimated abundance of 29 in 2016. As port developments and floods are expected to increase along the Queensland coastal region over coming decades, the results of this study highlight increasing concerns about the vulnerability and long term sustainability of inshore dolphins in the GBR.", "author_names": [ "Daniele Db Cagnazzi", "Guido J Parra", "Peter L Harrison", "Lyndon Owen Brooks", "Robert William Rankin" ], "corpus_id": 224873033, "doc_id": "224873033", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Vulnerability of threatened Australian humpback dolphins to flooding and port development within the southern Great Barrier Reef coastal region", "venue": "", "year": 2020 }, { "abstract": "Fermi level managed barrier diodes (FMBDs) are packaged with WR 3 rectangular metallic waveguides to ensure J band (220 325 GHz) operation. A broadband amplifier is integrated in the packaged module to be used as a receiver for high speed communications applications. Wireless transmission experiments at around 300 GHz with data rates up to 32 Gbit/s have been conducted for both direct and coherent detection schemes by using photonically generated RF and LO signals.", "author_names": [ "Tadao Nagatsuma", "Fumiya Ayano", "Keita Toichi", "Li Yi", "Masamichi Fujiwara", "Noriko Iiyama", "Jun-ichi Kani", "Hiroshi Ito" ], "corpus_id": 220346806, "doc_id": "220346806", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wireless Communication Using Fermi level managed Barrier Diode Receiver with J band Waveguide input Port", "venue": "2020 IEEE/MTT S International Microwave Symposium (IMS)", "year": 2020 }, { "abstract": "Abstract In June 2017 a wide ranging and protracted dispute between several members of the Gulf Cooperation Council (GCC) simmered over into the public sphere with the United Arab Emirates (UAE) Bahrain and Saudi Arabia all severing diplomatic ties with Qatar. This diplomatic dispute is accompanied by a number of port state and coastal state measures which includes the denial of the use of ports and the denial of innocent passage to vessels either linked to Qatar or carrying cargo linked to Qatar. This paper will use the current law of the sea framework to analyse the legality of the UAE's, Bahrain's and Saudi Arabia's Qatar related restrictions upon international shipping. This paper concludes that in both cases the three GCC states have a valid jurisdictional basis to adopt such measures, but the limitations of customary international law and the United Nations Convention on the Law of the Sea (UNCLOS) are arguably not being followed. The conclusion also touches upon whether the compulsory dispute settlement procedure found in Part XV of UNCLOS presents another avenue for flag states to challenge the restrictions on innocent passage imposed by Saudi Arabia and Bahrain as parties to UNCLOS.", "author_names": [ "Arron N Honniball" ], "corpus_id": 213368095, "doc_id": "213368095", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Port states, coastal states and national security: A law of the sea perspective on the 2017 Qatar Gulf crisis", "venue": "", "year": 2020 } ]

[ { "abstract": "We provide a broad review of fundamental electronic properties of two dimensional graphene with the emphasis on density and temperature dependent carrier transport in doped or gated graphene structures. A salient feature of our review is a critical comparison between carrier transport in graphene and in two dimensional semiconductor systems (e.g. heterostructures, quantum wells, inversion layers) so that the unique features of graphene electronic properties arising from its gap less, massless, chiral Dirac spectrum are highlighted. Experiment and theory as well as quantum and semi classical transport are discussed in a synergistic manner in order to provide a unified and comprehensive perspective. Although the emphasis of the review is on those aspects of graphene transport where reasonable consensus exists in the literature, open questions are discussed as well. Various physical mechanisms controlling transport are described in depth including long range charged impurity scattering, screening, short range defect scattering, phonon scattering, many body effects, Klein tunneling, minimum conductivity at the Dirac point, electron hole puddle formation, p n junctions, localization, percolation, quantum classical crossover, midgap states, quantum Hall effects, and other phenomena.", "author_names": [ "Sankar Das Sarma", "Shaffique Adam", "E H Hwang", "Enrico Rossi" ], "corpus_id": 118565433, "doc_id": "118565433", "n_citations": 2233, "n_key_citations": 55, "score": 1, "title": "Electronic transport in two dimensional graphene", "venue": "", "year": 2011 }, { "abstract": "1 Universite Catholique de Louvain (UCL) Institute of Condensed Matter and Nanoscience (IMCN) Place Croix du Sud 1 (NAPS Boltzmann) 1348 Louvain la Neuve, Belgium 2 European Theoretical Spectroscopy Facility (ETSF) 3 University of Cambridge, Cavendish Laboratory, Theory of Condensed Matter group, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom 4 Institut Catala de Nanotecnologia (ICN) and CIN2, UAB Campus, E 08193 Barcelona, Spain 5 Institucio Catalana de Recerca i Estudis Avancats (ICREA) 08010 Barcelona, Spain and 6 CEA UJF, INAC, SP2M/L_Sim, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France", "author_names": [ "Aurelien Lherbier", "Simon M -M Dubois", "Xavier Declerck", "Stephan Roche", "Yann-Michel Niquet", "Jean-Christophe Charlier" ], "corpus_id": 109186689, "doc_id": "109186689", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Electronic transport in two dimensional Graphene with structural defects", "venue": "", "year": 2011 }, { "abstract": "Two dimensional (2D) materials have captured the attention of the scientific community due to the wide range of unique properties at nanometer scale thicknesses. While significant exploratory research in 2D materials has been achieved, the understanding of 2D electronic transport and carrier dynamics remains in a nascent stage. Furthermore, because prior review articles have provided general overviews of 2D materials or specifically focused on charge transport in graphene, here we instead highlight charge transport mechanisms in post graphene 2D materials, with particular emphasis on transition metal dichalcogenides and black phosphorus. For these systems, we delineate the intricacies of electronic transport, including band structure control with thickness and external fields, valley polarization, scattering mechanisms, electrical contacts, and doping. In addition, electronic interactions between 2D materials are considered in the form of van der Waals heterojunctions and composite films. This review concludes with a perspective on the most promising future directions in this fast evolving field.", "author_names": [ "Vinod K Sangwan", "Mark C Hersam" ], "corpus_id": 3397465, "doc_id": "3397465", "n_citations": 114, "n_key_citations": 0, "score": 0, "title": "Electronic Transport in Two Dimensional Materials.", "venue": "Annual review of physical chemistry", "year": 2018 }, { "abstract": "Transport of carriers in two dimensional graphene at high electric fields is investigated by combining semianalytical and Monte Carlo methods. A semianalytical high field transport model based on the high rate of optical phonon emission provides useful estimates of the saturation currents in graphene. For developing a more accurate picture, the nonequilibrium (hot) phonon effect and the role of electron electron scattering were studied using Monte Carlo simulations. Monte Carlo simulations indicate that the hot phonon effect plays a dominant role in current saturation, and electron electron scattering strongly thermalizes the hot carrier population in graphene. We also find that electron electron scattering removes negative differential resistance in graphene. Transient phenomenon such as velocity overshoot can be used to speed up graphene based high speed electronic devices by shrinking the channel length below 80 nm if electrostatic control can be exercised in the absence of a band gap.", "author_names": [ "Tian Fang", "Aniruddha Konar", "Huili Grace Xing", "Debdeep Jena" ], "corpus_id": 14430134, "doc_id": "14430134", "n_citations": 89, "n_key_citations": 2, "score": 0, "title": "High field transport in two dimensional graphene", "venue": "", "year": 2011 }, { "abstract": "We calculate the temperature dependent conductivity of graphene in the presence of randomly distributed Coulomb impurity charges arising from the temperature dependent screening of the Coulomb disorder without any phonons. The purely electronic temperature dependence of our theory arises from two independent mechanisms: the explicit temperature dependence of the finite temperature dielectric function \\ensuremath{\\epsilon}(q,T) and the finite temperature energy averaging of the transport scattering time. We find that the calculated temperature dependent conductivity is nonmonotonic, decreasing with temperature at low temperatures, and increasing at high temperatures. We provide a critical comparison with the corresponding physics in semiconductor based parabolic band 2D electron gas systems.", "author_names": [ "E H Hwang", "Sankar Das Sarma" ], "corpus_id": 118729111, "doc_id": "118729111", "n_citations": 168, "n_key_citations": 3, "score": 0, "title": "Screening induced temperature dependent transport in two dimensional graphene", "venue": "", "year": 2009 }, { "abstract": "We discuss some basic physical properties of electron transport in two dimensional materials. First, we discuss how the predicted thermodynamic instability of 2D crystals may influence charge transport via the coupling of electrons with acoustic flexural modes. We then review the properties of suspended and supported graphene and its ribbons and consider the problem of evaluating correctly the electron phonon coupling in the case of phosphorene. Finally, we discuss the main features of 2D topological insulators and their possible use in transistors.", "author_names": [ "Massimo V Fischetti", "W G Vandehberghe" ], "corpus_id": 39142255, "doc_id": "39142255", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Physics of electronic transport in two dimensional materials for future FETs", "venue": "2016 IEEE International Electron Devices Meeting (IEDM)", "year": 2016 }, { "abstract": "Two dimensional superlattices are promising alternatives to traditional semiconductors for manufacturing power dissipating devices with enhanced thermal and electronic properties. The goal of this work is to investigate the influence of the superlattice secondary periodicity and atomic interface orientation on the phonon properties and thermal conductivity of two dimensional superlattices of graphene and boron nitride. We have employed harmonic lattice dynamics to predict the phonon group velocities and specific heats, and molecular dynamics to extract the relaxation times from normal mode analysis in the frequency domain. Density functional perturbation theory is applied to validate the phonon dispersion curves. The Boltzmann transport equation under single relaxation time approximation is then used to predict the thermal conductivities of the superlattices in the zigzag and armchair orientations with periodicities between one and five. Our results showed that the thermal conductivities increased by 15.68% when reducing the superlattice period from two to one. In addition, thermal conductivities parallel to the interface increase by 20.15% when switching the orientation from armchair to zigzag.Copyright (c) 2015 by ASME", "author_names": [ "Carlos da Silva", "Fernan Saiz", "David A Romero", "Cristina H Amon" ], "corpus_id": 137790308, "doc_id": "137790308", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Predicting Phonon Thermal Transport in Two Dimensional Graphene Boron Nitride Superlattices at the Short Period Limit", "venue": "", "year": 2015 }, { "abstract": "Nanoscience offers a unique opportunity to design modern materials from the bottom up via low cost, solution processed assembly of nanoscale building blocks. These systems promise electronic band structure engineering using not only the nanoscale structural modulation, but also the mesoscale spatial patterning, although experimental realization of the latter has been challenging. Here, we design and fabricate a new type of artificial solid by stacking graphene on a self assembled, nearly periodic array of nanospheres, and experimentally observe superlattice miniband effects. We find conductance dips at commensurate fillings of charge carriers per superlattice unit cell, which are key features of minibands that are induced by the quasi periodic deformation of the graphene lattice. These dips become stronger when the lattice strain is larger. Using a tight binding model, we simulate the effect of lattice deformation as a parameter affecting the inter atomic hopping integral, and confirm the superlattice transport behavior. This 2D material nanoparticle heterostructure enables facile band structure engineering via self assembly, promising for large area electronics and optoelectronics applications.Electronic transport: a 2D artificial solid shows superlattice miniband effectsA hybrid heterostructure of self assembled nanoparticles on graphene displays conductance dips due to superlattice miniband effects. A team led by Yingjie Zhang and Nadya Mason at the University of Illinois designed and fabricated a large area artificial solid combining self assembled dielectric nanospheres and graphene grown by chemical vapor deposition. Taking advantage of the structural versatility of SiO2 nanoparticle assembly and the high mobility of graphene, the resulting heterostructure displays miniband effects in the electronic transport characteristics as a result of superlattice formation. Due to the size variability and imperfect ordering of the nanospheres, a broadening was observed in the miniband density of states. This effect can find an application in optoelectronic devices, such as optical modulators and sensor, requiring broadband modulation of their optical spectrum.", "author_names": [ "Yingjie Zhang", "Youngseok Kim", "Matthew J Gilbert", "Nadya Mason" ], "corpus_id": 83458259, "doc_id": "83458259", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Electronic transport in a two dimensional superlattice engineered via self assembled nanostructures", "venue": "npj 2D Materials and Applications", "year": 2018 }, { "abstract": "Two dimensional photonic crystals, in analogy to AB/BA stacking bilayer graphene in electronic system, are studied. Inequivalent valleys in the momentum space for photons can be manipulated by simply engineering diameters of cylinders in a honeycomb lattice. The inequivalent valleys in photonic crystal are selectively excited by a designed optical chiral source and bulk valley polarizations are visualized. Unidirectional valley interface states are proved to exist on a domain wall connecting two photonic crystals with different valley Chern numbers. With the similar optical vortex index, interface states can couple with bulk valley polarizations and thus valley filter and valley coupler can be designed. Our simple dielectric PC scheme can help to exploit the valley degree of freedom for future optical devices.", "author_names": [ "Yuting Yang", "Hua Jiang", "Zhi Hong Hang" ], "corpus_id": 205644906, "doc_id": "205644906", "n_citations": 42, "n_key_citations": 1, "score": 0, "title": "Topological Valley Transport in Two dimensional Honeycomb Photonic Crystals", "venue": "Scientific Reports", "year": 2018 }, { "abstract": "After the first unequivocal demonstration of spin transport in graphene (Tombros et al. 2007) surprisingly at room temperature, it was quickly realized that this novel material was relevant for both fundamental spintronics and future applications. Over the decade since, exciting results have made the field of graphene spintronics blossom, and a second generation of studies has extended to new two dimensional (2D) compounds. This Colloquium reviews recent theoretical and experimental advances on electronic spin transport in graphene and related 2D materials, focusing on emergent phenomena in van der Waals heterostructures and the new perspectives provided by them. These phenomena include proximity enabled spin orbit effects, the coupling of electronic spin to light, electrical tunability, and 2D magnetism.", "author_names": [ "Ahmet Avsar", "H Ochoa", "Francisco Guinea", "", "Bart Jan van Wees", "Ivan J Vera-Marun" ], "corpus_id": 202712801, "doc_id": "202712801", "n_citations": 85, "n_key_citations": 0, "score": 0, "title": "Colloquium: Spintronics in graphene and other two dimensional materials", "venue": "", "year": 2020 } ]

[ { "abstract": "The inherent flexibility afforded by molecular design has accelerated the development of a wide variety of organic semiconductors over the past two decades. In particular, great advances have been made in the development of materials for organic light emitting diodes (OLEDs) from early devices based on fluorescent molecules to those using phosphorescent molecules. In OLEDs, electrically injected charge carriers recombine to form singlet and triplet excitons in a 1:3 ratio; the use of phosphorescent metal organic complexes exploits the normally non radiative triplet excitons and so enhances the overall electroluminescence efficiency. Here we report a class of metal free organic electroluminescent molecules in which the energy gap between the singlet and triplet excited states is minimized by design, thereby promoting highly efficient spin up conversion from non radiative triplet states to radiative singlet states while maintaining high radiative decay rates, of more than 106 decays per second. In other words, these molecules harness both singlet and triplet excitons for light emission through fluorescence decay channels, leading to an intrinsic fluorescence efficiency in excess of 90 per cent and a very high external electroluminescence efficiency, of more than 19 per cent, which is comparable to that achieved in high efficiency phosphorescence based OLEDs.", "author_names": [ "Hiroki Uoyama", "Kenichi Goushi", "Katsuyuki Shizu", "Hiroko Nomura", "Chihaya Adachi" ], "corpus_id": 4376505, "doc_id": "4376505", "n_citations": 3562, "n_key_citations": 27, "score": 1, "title": "Highly efficient organic light emitting diodes from delayed fluorescence", "venue": "Nature", "year": 2012 }, { "abstract": "Abstract Organic Light Emitting Diodes (OLEDs) using the thermally activated delayed fluorescence (TADF) emitter (4s,6s) 2,4,5,6 tetra(9H carbazol 9 yl)isophthalonitrile (4CzIPN) are demonstrated using a novel ambipolar host 3,5 di(carbazol 9 yl) 1 phenylsulfonylbenzene (mCPSOB) When doped in a 5 wt. concentration, OLEDs with EL efficiency values of more than 81 cd/A for current efficacy and 26.5% for external quantum efficiency are reported. These devices exhibit a low turn on voltage of 3.2 V at 10 cd/m2, as well as reduced efficiency roll off at high current densities. To the best of our knowledge, these are among the highest ever reported efficiencies for TADF OLEDs, and are even comparable to the highest reported efficiencies for phosphorescent OLEDs.", "author_names": [ "Michael P Gaj", "Canek Fuentes-Hernandez", "Yadong Zhang", "Seth R Marder", "Bernard Kippelen" ], "corpus_id": 98532335, "doc_id": "98532335", "n_citations": 49, "n_key_citations": 0, "score": 0, "title": "Highly efficient Organic Light Emitting Diodes from thermally activated delayed fluorescence using a sulfone carbazole host material", "venue": "", "year": 2015 }, { "abstract": "Abstract The development of high performance universal host materials for both blue electrophosphorescence and thermally activated delayed fluorescence (TADF) is one of the main challenges for organic light emitting diode (OLED) technology. In this work, based on four quaternary ambipolar hosts with insulated donor acceptor (D A) structures, the influence of the excited state characteristics for these hosts on their device performance was systematically investigated. It was showed that on the premise of the similar electrical properties and excited state energy levels for positive host dopant energy transfer (ET) the weak exciton capture ability, embodied as low exciton binding energy (Eb) for the hosts could facilitate the Dexter ET to the dopant through charge migration. Since the charge transfer featured excited states and small Eb of blue TADF emitters, in contrast to the blue phosphorescence (PH) counterparts, the influence of the host Eb on the device efficiencies of blue TADF dyes was dramatically enlarged, reflecting the higher sensitivity of the latter to host characteristics. In consequence, 9CzFDBFDPO with the smallest Eb endowed its blue TADF and PH devices with the state of the art performance, e.g. EQE beyond 20% and EQE roll off within 20% at 500 cd m 2. This work showed that based on the systematically optimized excited state characteristics, the ambipolar hosts can be competent in both high efficiency blue PH and TADF OLEDs, which is crucial for their commercial applications.", "author_names": [ "Zhen Zhang", "Dongxue Ding", "Ying Wei", "Jinwei Zhang", "Chunmiao Han", "Hui Xu" ], "corpus_id": 202034491, "doc_id": "202034491", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Excited state engineering of universal ambipolar hosts for highly efficient blue phosphorescence and thermally activated delayed fluorescence organic light emitting diodes", "venue": "", "year": 2020 }, { "abstract": "Two benzoylpyridine carbazole based fluorescence materials DCBPy and DTCBPy, bearing two carbazolyl and 4 (t butyl)carbazolyl groups, respectively, at the meta and ortho carbons of the benzoyl ring, were synthesized. These molecules show very small DEST of 0.03 and 0.04 eV and transient PL characteristics indicating that they are thermally activated delayed fluorescence (TADF) materials. In addition, they show extremely different photoluminescent quantum yields in solution and in the solid state: in cyclohexane the value are 14 and 36% but in the thin films, the value increase to 88.0 and 91.4% respectively. The OLEDs using DCBPy and DTCBPy as dopants emit blue and green light with EQEs of 24.0 and 27.2% respectively, and with low efficiency roll off at practical brightness level. The crystal structure of DTCBPy reveals a substantial interaction between the ortho donor (carbazolyl) and acceptor (4 pyridylcarbonyl) unit. This interaction between donor and acceptor substituents likely play a key role to achieve very small DEST with high photoluminescence quantum yield.", "author_names": [ "Pachaiyappan Rajamalli", "Natarajan Senthilkumar", "Parthasarathy Gandeepan", "Pei-Yun Huang", "Min-Jie Huang", "Chen-Zheng Ren-Wu", "Chi-Yu Yang", "Ming-Jui Chiu", "Li-Kang Chu", "Hao-Wu Lin", "Chien-Hong Cheng" ], "corpus_id": 207161371, "doc_id": "207161371", "n_citations": 254, "n_key_citations": 0, "score": 0, "title": "A New Molecular Design Based on Thermally Activated Delayed Fluorescence for Highly Efficient Organic Light Emitting Diodes.", "venue": "Journal of the American Chemical Society", "year": 2016 }, { "abstract": "Abstract In this work, we describe a new approach of improving the external quantum efficiency (EQE) of exciplex organic light emitting diodes (OLEDs) A new approach of dispersing the exciplex in the thermally activated delayed fluorescence (TADF) host was developed to increase the EQE of the exciplex OLEDs. The new emitting layer structure was made up of a mixture of TADF material and an n type material which can generate exciplex with the TADF material. The content of the n type material was maintained below 10 wt to have a morphology with the exciplex dispersed in the TADF matrix material. The emitting layer structure with the exciplex dispersed in the TADF host suppressed exciton quenching and improved the photoluminescence quantum yield of the exciplex. As a result, the exciplex OLEDs with the n type material content of 1 wt% showed high EQE of 15.3% compared with EQE of 10.8% of the conventional exciplex OLEDs with the n type material content of 50%", "author_names": [ "Sang Kyu Jeon", "Jun Yeob Lee" ], "corpus_id": 208724825, "doc_id": "208724825", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Highly efficient exciplex organic light emitting diodes by exciplex dispersion in the thermally activated delayed fluorescence host", "venue": "", "year": 2020 }, { "abstract": "Aromatic imide based thermally activated delayed fluorescence (TADF) materials with a twisted donor acceptor donor skeleton were efficiently synthesized and exhibited excellent thermal stability and high photoluminescence quantum yields. The small DEST value <0.1 eV) along with the clear temperature dependent delayed component of their transient photoluminescence (PL) spectra demonstrated their excellent TADF properties. Moreover, the performance of organic light emitting diodes in which TADF materials AI Cz and AI TBCz were used as dopants were outstanding, with external quantum efficiencies up to 23.2 and 21.1 respectively.", "author_names": [ "Meng Li", "Yanwei Liu", "Ruihong Duan", "Xiaofang Wei", "Yuanping Yi", "Chuan-Feng Chen" ], "corpus_id": 205402587, "doc_id": "205402587", "n_citations": 69, "n_key_citations": 0, "score": 0, "title": "Aromatic Imide Based Thermally Activated Delayed Fluorescence Materials for Highly Efficient Organic Light Emitting Diodes.", "venue": "Angewandte Chemie", "year": 2017 }, { "abstract": "Two new blue TADF emitters, namely, 9' (2,12 di tert butyl 5,9 dioxa 13b boranaphtho[3,2,1 de]anthracen 7 yl) 9,9' diphenyl 9H,9'H,9''H 3,3':6',3' tercarbazole (3CzTB) and 9' (5,9 dioxa 13b boranaphtho[3,2,1 de]anthracen 7 yl) 6,6' dimethyl 9,9' diphenyl 9H,9'H,9''H 3,3':6',3' tercarbazole (M3CzB) for application in highly efficient organic light emitting diodes are reported. These emitters consist of tercarbazole as donor and rigid oxygen bridged boron as acceptor units. Despite having the same donor and acceptor segments, an alkyl modification on the periphery of the donor and acceptor units altered their physicochemical properties and the electrochemical stability of the emitters. Blue TADF light emitting devices fabricated with these emitters exhibited a maximum external quantum efficiency (EQE) and luminance of 30.7% 18 160 cd m 2 and 29.1% 11 690 cd m 2 for M3CzB and 3CzTB, respectively. The operational lifetime (LT50) of the stable blue TADF device fabricated with these emitters was 81 h and 60.5 h at 400 nits with the maximum EQE and CIE color coordinates of 14.4% (0.13, 0.19) and 7.6% (0.14, 0.10) for M3CzB and 3CzTB, respectively.", "author_names": [ "Durai Karthik", "Dae Hyun Ahn", "Jaemin Ryu", "Hyuna Lee", "Jee Hyun Maeng", "Ju Young Lee", "Jang Hyuk Kwon" ], "corpus_id": 213097757, "doc_id": "213097757", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Highly efficient blue thermally activated delayed fluorescence organic light emitting diodes based on tercarbazole donor and boron acceptor dyads", "venue": "", "year": 2020 }, { "abstract": "Luminescent materials with aggregation induced emission (AIE) properties exhibit high solid state emission, while thermally activated delayed fluorescence (TADF) materials can fully harvest singlet and triplet excitons to achieve efficient electroluminescence (EL) Herein, the amalgamation of AIE and TADF properties, termed aggregation induced emission and thermally activated delayed fluorescence (AIE TADF) is a promising strategy to design novel desirable luminescent materials. In this paper, a new tailor made material, DCPDAPM, is obtained based on carbazole as the skeleton, 9,9 dimethyl 9,10 dihydroacridine as the donor group and benzophenone as the acceptor group. Its structure is fully characterized by elemental analysis, NMR spectroscopy and mass spectrometry. Furthermore, its thermal stability, photophysical properties, and electrochemical properties are investigated systematically. The results show that this AIE TADF compound exhibits good thermal stability, electrochemical stability and AIE and TADF properties. Ultimately, using DCPDAPM and DCPDAPM doped into CBP as light emitting layers, a non doped OLED (device A) and doped OLEDs (device B, device C and device D) were fabricated and studied. Device A displays green light with a turn on voltage of 3.2 V, a maximum brightness of 123 371 cd m 2, a maximum current efficiency of 26.88 cd A 1, a maximum power efficiency of 15.63 lm W 1 and an external quantum efficiency of 8.15% Among the doped OLEDs (device B, device C and device D) device D shows the best EL performance with a turn on voltage of 3.6 V, a maximum brightness of 116 100 cd m 2, a maximum current efficiency of 61.83 cd A 1, a maximum power efficiency of 40.45 lm W 1 and an external quantum efficiency of 19.67% These results adequately demonstrate the practicability of combining AIE and TADF to explore new efficient emitters.", "author_names": [ "Yaodong Zhao", "Weigao Wang", "Chen Gui", "Li Fang", "Xinlei Zhang", "Shujuan Wang", "Shuming Chen", "He-ping Shi", "Ben Zhong Tang" ], "corpus_id": 139127398, "doc_id": "139127398", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Thermally activated delayed fluorescence material with aggregation induced emission properties for highly efficient organic light emitting diodes", "venue": "", "year": 2018 }, { "abstract": "Three highly efficient blue thermally activated delayed fluorescence (TADF) emitters, 2SPAc HPM, 2SPAc MPM and 2SPAc PPM, have been synthesised based on pyrimidine (PM) 2 methylpyrimidine (MPM) and 2 phenylpyrimidine (PPM) as the acceptor and 10H spiro[acridan 9,9' fluorene] (2SPAc) as the donor moiety. With their appropriate molecular design, these emitters successfully achieve small singlet triplet splitting energies for efficient reverse intersystem crossing, and exhibit high photoluminescence quantum yields. As a result, TADF OLEDs based on 2SPAc HPM, 2SPAc MPM and 2SPAc PPM emit blue light peaking at 479 489 nm and generate very high external quantum efficiencies of 25.56% 24.34% and 31.45% respectively. The 2SPAc PPM based TADF OLED is also one of the very few blue TADF emitters with an external quantum efficiency of more than 30% and it has the best OLED performance among the pyrimidine based TADF emitters.", "author_names": [ "Bowen Li", "Zhi-yi Li", "Taiping Hu", "Yong Zhang", "Ying Wang", "Yuanping Yi", "Feng-yun Guo", "Liancheng Zhao" ], "corpus_id": 140034250, "doc_id": "140034250", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Highly efficient blue organic light emitting diodes from pyrimidine based thermally activated delayed fluorescence emitters", "venue": "", "year": 2018 }, { "abstract": "Abstract Three new emitters, namely 10,10' (quinoline 2,8 diyl)bis(10H phenoxazine) (Fene) 10,10' (quinoline 2,8 diyl)bis(10H phenothiazine) (Fens) and 10,10' (quinoline 2,8 diyl)bis(9,9 dimethyl 9,10 dihydroacridine) (Yad) featuring quinoline as a new electron acceptor have been designed and conveniently synthesized. These emitters possessed small singlet triplet splitting energy (DEst) and twisted structures, which not only endowed them show thermally activated delayed fluorescence (TADF) properties but also afforded a remarkable aggregation induced emission (AIE) feature. Moreover, they also showed aggregation induced delayed fluorescence (AIDF) property and good photoluminescence (PL) property, which are the ideal emitters for non doped organic light emitting diodes (OLEDs) Furthermore, high performance non doped OLEDs based on Fene, Fens and Yad were achieved, and excellent maximum external quantum efficiencies (EQEmax) of 14.9% 13.1% and 17.4% respectively, were obtained. It was also found that all devices exhibited relatively low turn on voltages ranging from 3.0 V to 3.2 V probably due to their twisted conformation and the AIDF properties. These results demonstrated the quinoline based emitters could have a promising application in non doped OLEDs.", "author_names": [ "Lianwei Zhang", "Yin-Feng Wang", "Mengting Li", "Qingyu Gao", "Chuan-Feng Chen" ], "corpus_id": 225475388, "doc_id": "225475388", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Quinoline based aggregation induced delayed fluorescence materials for highly efficient non doped organic light emitting diodes", "venue": "", "year": 2020 } ]

[ { "abstract": "Metal oxide semiconductor (MOS) devices and integrated circuits can only be realised with semiconductor materials. The substrate material on which they are built plays a very dominant role in their performance and reliability. Aware of this fact, Lilienfeld used copper sulphide as a semiconductor starting material in 1930. Germanium was used during the early 1950s. Until 1960, however, usable MOS transistors could not be manufactured. During the 1960s, the move from germanium to silicon was made in which the transistor channel is a thin conductive layer, which is realised electrically. Table 8.1 shows a comparison of a few germanium (Ge) and silicon (Si) material constants, which clearly shows a few reasons why silicon is used today. For example, the circuits designed in the 65 nm CMOS node use transistors with a channel length close to 60 nm while operating at 1.2 V. This causes an electric field in the channel of 20 V/mm, which is much more than the maximum breakdown field in germanium but still less than that in silicon. Another reason is the widely accepted military spec, which can be met with this material. This spec requires products to function correctly at a maximum operating temperature of 125 degC. The maximum operating temperature of germanium is only 70 degC, while that of silicon is 150 degC. A major reason for these maximum temperatures is that, for many applications, the leakage currents become unacceptably large above these temperatures. Another advantage of silicon is that it is cheap because it is widely available as (beach) sand.", "author_names": [ "Harry J M Veendrick" ], "corpus_id": 117683285, "doc_id": "117683285", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Wafers and Transistors", "venue": "", "year": 2019 }, { "abstract": "This letter introduces a type of thin film transistor that uses aligned arrays of thin (submicron) ribbons of single crystal silicon created by lithographic patterning and anisotropic etching of bulk silicon (111) wafers. Devices that incorporate such ribbons printed onto thin plastic substrates show good electrical properties and mechanical flexibility. Effective device mobilities, as evaluated in the linear regime, were as high as 360cm2V 1s 1, and on/off ratios were >103. These results may represent important steps toward a low cost approach to large area, high performance, mechanically flexible electronic systems for structural health monitors, sensors, displays, and other applications.", "author_names": [ "Shawn Mack", "Matthew A Meitl", "Alfred J Baca", "Zhengtao Zhu", "John A Rogers" ], "corpus_id": 108451535, "doc_id": "108451535", "n_citations": 156, "n_key_citations": 1, "score": 0, "title": "Mechanically flexible thin film transistors that use ultrathin ribbons of silicon derived from bulk wafers", "venue": "", "year": 2006 }, { "abstract": "This letter presents a simple method for transferring epitaxial sheets of graphene on silicon carbide to other substrates. The graphene was grown on the (0001) face of 6H SiC by thermal annealing at 1550 degC in a hydrogen atmosphere. Transfer was accomplished using a peeling process with a bilayer film of gold/polyimide, to yield graphene with square millimeters of coverage on the target substrate. Raman spectroscopy provided evidence that the transferred material is single layer. Back gated field effect transistors fabricated on oxidized silicon substrates with Cr/Au as source drain electrodes exhibited ambipolar characteristics with hole mobilities of ~100 cm2/V s, and negligible influence of resistance at the contacts.", "author_names": [ "Sakulsuk Unarunotai", "Yuya Murata", "Cesar E Chialvo", "Hoon-sik Kim", "Scott Maclaren", "Nadya Mason", "Ivan Petrov", "John A Rogers" ], "corpus_id": 14687784, "doc_id": "14687784", "n_citations": 79, "n_key_citations": 1, "score": 0, "title": "Transfer of graphene layers grown on SiC wafers to other substrates and their integration into field effect transistors", "venue": "", "year": 2009 }, { "abstract": "This letter presents a method to fabricate single crystal silicon wires from (100) wafer and print them onto thin plastic substrates for high performance, mechanically flexible, thin film transistors by dry transfer printing. Electrical measurements indicate excellent performance, with a per ribbon mobility of 580 cm2/V s, subthreshold voltage of 100 mV/dec and on/off ratios >107. The inverter shows good performance and voltage gains of ~2.5 at 3 V supply voltage. In addition, these devices revealed stable performance at bending configuration, an important feature essential for flexible electronic systems.", "author_names": [ "Seoung-Ki Lee", "Houk Jang", "Musarrat Hasan", "Jae Bon Koo", "Jong-Hyun Ahn" ], "corpus_id": 110221480, "doc_id": "110221480", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Mechanically flexible thin film transistors and logic gates on plastic substrates by use of single crystal silicon wires from bulk wafers", "venue": "", "year": 2010 }, { "abstract": "A new technique is presented for separating the threshold voltage shift of an MOS transistor into shifts due to interface states and trapped oxide charge. Using this technique, the radiation responses of MOS capacitors and transistors fabricated on the same wafer are compared. A good correlation is observed between p substrate capacitors and n channel transistors irradiated at 10 V, as well as between n substrate capacitors and p channel transistors irradiated at 0 V. These correlations were verified for samples having large variations in the amount of radiation induced trapped holes and interface states. An excellent correlation is also observed between n channel capacitors and n substrate transistors irradiated under positive bias. The use of capacitors separately fabricated on control wafers for potential use in process development or monitoring is clearly demonstrated.", "author_names": [ "Peter S Winokur", "J R Schwank", "Paul J McWhorter", "Paul V Dressendorfer", "Daniel Turpin" ], "corpus_id": 27098337, "doc_id": "27098337", "n_citations": 385, "n_key_citations": 14, "score": 0, "title": "Correlating the Radiation Response of MOS Capacitors and Transistors", "venue": "IEEE Transactions on Nuclear Science", "year": 1984 }, { "abstract": "Obtaining a subthreshold swing (SS) below the thermionic limit of 60 mV dec 1 by exploiting the negative capacitance (NC) effect in ferroelectric (FE) materials is a novel effective technique to allow the reduction of the supply voltage and power consumption in field effect transistors (FETs) At the same time, two dimensional layered semiconductors, such as molybdenum disulfide (MoS2) have been shown to be promising candidates to replace silicon MOSFETs in sub 5 nm channel technology nodes. In this paper, we demonstrate NC MoS2 FETs by incorporating a ferroelectric Al doped HfO2 (Al HfO2) a technologically compatible material, in the FET gate stack. Al HfO2 thin films were deposited on Si wafers by atomic layer deposition. Voltage amplification up to 1.25 times was observed in a FE bilayer stack of Al HfO2/HfO2 with a Ni metallic intermediate layer. The minimum SS (SSmin) of the NC MoS2 FET built on the FE bilayer improved to 57 mV dec 1 at room temperature, compared with SSmin 67 mV dec 1 for the MoS2 FET with only HfO2 as a gate dielectric.", "author_names": [ "Amirhasan Nourbakhsh", "Ahmad Zubair", "Sameer Joglekar", "Mildred S Dresselhaus", "Tomas Palacios" ], "corpus_id": 206096391, "doc_id": "206096391", "n_citations": 87, "n_key_citations": 4, "score": 0, "title": "Subthreshold swing improvement in MoS2 transistors by the negative capacitance effect in a ferroelectric Al doped HfO2/HfO2 gate dielectric stack.", "venue": "Nanoscale", "year": 2017 }, { "abstract": "This paper presents an innovative approach for wafer scale transfer of ultrathin silicon chips on flexible substrates. The methodology is demonstrated with various devices (ultrathin chip resistive samples, metal oxide semiconductor (MOS) capacitors and n channel metal oxide semiconductor field effect transistors (MOSFETs) on wafers up to 4' diameter. This is supported by extensive electromechanical characterization and theoretical analysis, including finite element simulation, to evaluate the effect of bending and the critical breaking radius of curvature. The ultrathin chips on polyimide did not break until the radius of curvature of 1.437 mm. In the case of MOS capacitors the measured capacitance increases with increase in bending load. The changes in the transfer and output characteristics of ultrathin MOSFETs closely match with the theoretical model utilizing empirically determined parameters. Overall, the work demonstrates the efficacy of the new methodology presented here for wafer scale transfer of ultrathin chips on flexible substrates. The presented research will be useful for obtaining high performance and compact circuits needed in many futuristic flexible electronics applications such as implantable electronics and flexible displays. Further, it will open new avenues for realizing multilayered multimaterial (foil to foil) integrated bendable electronics.", "author_names": [ "William Taube Navaraj", "Shoubhik Gupta", "Leandro Lorenzelli", "Ravinder S Dahiya" ], "corpus_id": 85547788, "doc_id": "85547788", "n_citations": 43, "n_key_citations": 3, "score": 0, "title": "Wafer Scale Transfer of Ultrathin Silicon Chips on Flexible Substrates for High Performance Bendable Systems", "venue": "", "year": 2018 }, { "abstract": "This paper describes the details of a novel strained transistor architecture which is incorporated into a 90nm logic technology on 300mm wafers. The unique strained PMOS transistor structure features an epitaxially grown strained SiGe film embedded in the source drain regions. Dramatic performance enhancement relative to unstrained devices are reported. These transistors have gate length of 45nm and 50nm for NMOS and PMOS respectively, 1.2nm physical gate oxide and Ni salicide. World record PMOS drive currents of 700/spl mu/A//spl mu/m (high V/sub T/ and 800/spl mu/A//spl mu/m (low V/sub T/ at 1.2V are demonstrated. NMOS devices exercise a highly tensile silicon nitride capping layer to induce tensile strain in the NMOS channel region. High NMOS drive currents of 1.26mA//spl mu/m (high VT) and 1.45mA//spl mu/m (low VT) at 1.2V are reported. The technology is mature and is being ramped into high volume manufacturing to fabricate next generation Pentium/spl reg/ and Intel/spl reg/ Centrino/spl trade/ processor families.", "author_names": [ "Tahir Ghani", "Mark Armstrong", "Chris Auth", "M Bost", "Peter K Charvat", "Glenn A Glass", "T Hoffmann", "K L Johnson", "C Kenyon", "J Klaus", "B Mcintyre", "Kaizad Mistry", "Anand Portland Murthy", "Justin S Sandford", "Mark Silberstein", "S Sivakumar", "P Smith", "Keith Zawadzki", "Scott E Thompson", "Mark T Bohr" ], "corpus_id": 44853052, "doc_id": "44853052", "n_citations": 519, "n_key_citations": 28, "score": 0, "title": "A 90nm high volume manufacturing logic technology featuring novel 45nm gate length strained silicon CMOS transistors", "venue": "IEEE International Electron Devices Meeting 2003", "year": 2003 }, { "abstract": "This paper presents a subthreshold voltage reference in which the output voltage is scalable depending on the number of stacked PMOS transistors. A key advantage is that its output voltage can be higher than that obtained with conventional low power subthreshold voltage references. The proposed reference uses native NMOS transistors as a current source and develops a reference voltage by stacking one or more PMOS transistors. The temperature coefficient of the reference voltage is compensated by setting the size ratio of the native NMOS and stacked pMOS transistors to cancel temperature dependence of transistor threshold voltage and thermal voltage. Also, the transistor size is determined considering the trade off between diode current between n well and p sub and process variation. Prototype chips are fabricated in a 0.18 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} /tex math>/inline formula> CMOS process. Measurement results from three wafers show <inline formula> <tex math notation=\"LaTeX\"$3\\sigma /tex math>/inline formula> inaccuracy of 1.0% from 0 degC to 100 degC after a single room temperature trim. The proposed voltage reference achieves a line sensitivity of 0.31%/V and a power supply rejection of 41 dB while consuming 35 pW from 1.4 V at room temperature.", "author_names": [ "Inhee Lee", "Dennis Sylvester", "David Blaauw" ], "corpus_id": 27016529, "doc_id": "27016529", "n_citations": 93, "n_key_citations": 8, "score": 0, "title": "A Subthreshold Voltage Reference With Scalable Output Voltage for Low Power IoT Systems", "venue": "IEEE Journal of Solid State Circuits", "year": 2017 }, { "abstract": "Ultra thin MoS2 has recently emerged as a promising two dimensional semiconductor for electronic and optoelectronic applications. Here, we report high mobility >60 cm2/Vs at room temperature) field effect transistors that employ unencapsulated single layer MoS2 on oxidized Si wafers with a low level of extrinsic contamination. While charge transport in the sub threshold regime is consistent with a variable range hopping model, monotonically decreasing field effect mobility with increasing temperature suggests band like transport in the linear regime. At temperatures below 100 K, temperature independent mobility is limited by Coulomb scattering, whereas, at temperatures above 100 K, phonon limited mobility decreases as a power law with increasing temperature.", "author_names": [ "Deep Jariwala", "Vinod K Sangwan", "Dattatray J Late", "James E Johns", "Vinayak P Dravid", "Tobin J Marks", "Lincoln J Lauhon", "Mark C Hersam" ], "corpus_id": 119232249, "doc_id": "119232249", "n_citations": 309, "n_key_citations": 2, "score": 0, "title": "Band like transport in high mobility unencapsulated single layer MoS 2 transistors", "venue": "", "year": 2013 } ]

[ { "abstract": "In recent years, wide band gap semiconductor materials silicon carbide (SiC) and gallium nitride (GaN) are receiving widespread attention because of their superior performance. In particular, GaN devices have been applied in the fields of low voltage miniaturized power supplies and 5G communications. For GaN high electron mobility transistor (HEMT) devices used in miniaturized power supplies, the lower threshold voltage (Vth) is a problem that needs to be solved urgently. In this paper, the HEMT device having a novel mixed conducting channel. The device raises the threshold voltage to 3.21V while the saturation current capability still reached 0.46A/mm. As with conventional devices, the saturation current capability of the new device is affected by the Al composition of the barrier layer. But unlike conventional devices, the threshold voltage of the device can be adjusted by changing the doping concentration of the p type doped layer within a certain range.", "author_names": [ "Wanjie Li", "Luqi Tao", "Liming Wang", "Xu Zhang", "Xiandong Li", "Xianping Chen" ], "corpus_id": 221915921, "doc_id": "221915921", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "High threshold voltage GaN HEMT with mixed conductive channel", "venue": "2020 21st International Conference on Electronic Packaging Technology (ICEPT)", "year": 2020 }, { "abstract": "Abstract The formation of partial AlGaN trench recess filled with multiple fluorinated gate dielectric layers as metal insulator semiconductor (MIS) gate structure for GaN based HEMT power devices is designed, fabricated and experimentally verified. The approach realizes the device normally off operational mode and at the same time is able to preserve the good mobility in the 2DEG channel for a maximum on state current. Experimental measurements on the fabricated MIS HEMT devices indicate a high gate threshold voltage V th at around 5 V and a very low gate leakage current at pA/mm level. This proposed gate structure provides very promising properties for GaN based power semiconductor devices in future power electronics switching applications.", "author_names": [ "Huolin Huang", "Yung C Liang" ], "corpus_id": 94749239, "doc_id": "94749239", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Formation of combined partially recessed and multiple fluorinated dielectric layers gate structures for high threshold voltage GaN based HEMT power devices", "venue": "", "year": 2015 }, { "abstract": "Normally off p gallium nitride (GaN) gate high electron mobility transistors (HEMTs) on silicon substrate were fabricated with hydrogen plasma treatment technology, which features a high resistivity cap layer (HRCL) at the access region. With hydrogen plasma treatment at the access region, the normally off operation was obtained with a threshold voltage of +2.5 V based on the linear extrapolation of the transfer curve. The fabricated HRCL HEMT with a gate width of 49.7 mm exhibits a maximum drain current of 10 A at V GS 8 V and a high off state breakdown voltage of 567 V at V GS 0 V with substrate grounded. Meanwhile, the HRCL HEMT also shows low gate leakage current of 1.3 x 10 7 and 3.3 x 10 10 A/mm at V GS 8 V and 30 V, respectively. The positive threshold voltage, high drain current, high breakdown voltage and low gate leakage show the potential of HRCL HEMT for power switching applications.", "author_names": [ "Ronghui Hao", "Dongdong Wu", "Kai Fu", "S H Liang", "Chen Fu", "Jie Zhao", "Zhongkai Du", "Bingliang Zhang", "Qilong Wang", "Guohao Yu", "Kai Cheng", "Yong Cai", "Xinping Zhang", "Baoshun Zhang" ], "corpus_id": 125193453, "doc_id": "125193453", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "10 A/567 V normally off p GaN gate HEMT with high threshold voltage and low gate leakage current", "venue": "", "year": 2018 }, { "abstract": "Temperature dependent threshold voltage (Vth) stability is a significant issue in the practical application of semi conductor power devices, especially when they are undergoing a repeated high temperature operation condition. The Vth analytical model and its stability are dependent on high temperature operations in wide bandgap gallium nitride (GaN) based high electron mobility transistor (HEMT) devices that were investigated in this work. The temperature effects on the physical parameters such as barrier height, conduction band, and polarization charge were analysed to understand the mechanism of Vth stability. The Vth analytical model under high temperature operation was then proposed and developed to study the measurement temperatures and repeated rounds dependent on Vth stability. The validity of the model was verified by comparing the theoretical calculation data with the experimental measurement and technology computer aided design (TCAD) simulation results. This work provides an effective theoretical reference on the Vth stability of power devices in practical, high temperature applications.", "author_names": [ "Huolin Huang", "Feiyu Li", "Zhonghao Sun", "Yaqing Cao" ], "corpus_id": 56178449, "doc_id": "56178449", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Model Development for Threshold Voltage Stability Dependent on High Temperature Operations in Wide Bandgap GaN Based HEMT Power Devices", "venue": "Micromachines", "year": 2018 }, { "abstract": "We present an AlGaN/GaN high electron mobility transistor (HEMT) operating in enhancement mode (E mode) with metal insulator semiconductor (MIS) structure showing improved threshold voltage. The design includes an aluminium gallium nitride (Alo.3Gao.7N) barrier layer of 5 nm thickness and a silicon nitride (SiN) passivation layer. The passivation layer is used for controlling the charge density of electron gas in 2 dimension (2DEG) While aluminium oxide (Ah03) on AIGaN does not change the 2DEG charge density in the hetero interface, it increases the threshold voltage in enhancement mode. MIS HEMT operating in E mode shows a peak drain current density (IDS) of 975mA/mm and a threshold voltage (Vth) of 1.25 V. The drain current density can be increased with the increase of barrier layer charge concentration. On/off ratio and threshold voltage are compared with existing design available in literature. The significant improvement of device performance metrics can be done by controlling the charge concentration and the thickness of Alo.3Gao.7N barrier layer.", "author_names": [ "Mansura Sadek", "Md Kawsar Alam" ], "corpus_id": 59619517, "doc_id": "59619517", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Threshold Voltage Improvement of Enhancement Mode Al2O3/ AIGaN/GaN MIS HEMT with High Drain Current Density", "venue": "2018 10th International Conference on Electrical and Computer Engineering (ICECE)", "year": 2018 }, { "abstract": "", "author_names": [ "Weijia Zhang" ], "corpus_id": 114708158, "doc_id": "114708158", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Gate Sinking Threshold Voltage Adjustment Technique for High Voltage GaN HEMT", "venue": "", "year": 2015 }, { "abstract": "Fabrication of enhancement mode high electron mobility transistors (E HEMTs) on GaN/AlGaN heterostructures grown on SiC substrates is reported. Enhancement mode operation was achieved with high threshold voltage (V/sub T/ through the combination of low damage and controllable dry gate recessing and the annealing of the Ni/Au gates. As recessed E HEMTs with 1.0 /spl mu/m gates exhibited a threshold voltage (V/sub T/ of 0.35 V, maximum drain current (I/sub D,max/ of 505 mA/mm, and maximum transconductance (g/sub m,max/ of 345 mS/mm; the corresponding post gate anneal characteristics were 0.47 V, 455 mA/mm and 310 mS/mm, respectively. The RF performance is unaffected by the post gate anneal process with a unity current gain cutoff frequency (f/sub T/ of 10 GHz.", "author_names": [ "William B Lanford", "T P Tanaka", "Yohei Otoki", "Ilesanmi Adesida" ], "corpus_id": 110345771, "doc_id": "110345771", "n_citations": 190, "n_key_citations": 3, "score": 0, "title": "Recessed gate enhancement mode GaN HEMT with high threshold voltage", "venue": "", "year": 2005 }, { "abstract": "The shifts of electrical parameters for p GaN high electron mobility transistor (HEMT) under high off state bias stress with negative gate voltage are investigated in this paper. Comparing to the conventional off state bias stress with zero gate voltage, a more significant positive shift of threshold voltage and a more evident decrease of gate leakage current were observed under negative gate bias stress condition. The dominant degradation mechanism is suggested that electron traps induced by high electric field at gate source access region capture more electrons in the barrier layer with the increasing negative gate bias. This work is of significance for the researches on the long term reliability of the practical system using p GaN HEMT device.", "author_names": [ "Chi Zhang", "Sihui Li", "Siyang Liu", "Jiaxing Wei", "Wangran Wu", "Weifeng Sun" ], "corpus_id": 211061070, "doc_id": "211061070", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Electrical Degradations of p GaN HEMT under High Off state Bias Stress with Negative Gate Voltage", "venue": "2019 IEEE 26th International Symposium on Physical and Failure Analysis of Integrated Circuits (IPFA)", "year": 2019 }, { "abstract": "Abstract This article reports negative shift in the threshold voltage in AlGaN/GaN high electron mobility transistor (HEMT) with application of reverse gate bias stress. The device is biased in strong pinch off and low drain to source voltage condition for a fixed time duration (reverse gate bias stress) followed by measurement of transfer characteristics. Negative threshold voltage shift after application of reverse gate bias stress indicates the presence of more carriers in channel as compared to the unstressed condition. We propose the presence of AlGaN/GaN interface states to be the reason of negative threshold voltage shift, and developed a process to electrically characterize AlGaN/GaN interface states. We verified the results with Technology Computer Aided Design (TCAD) ATLAS simulation and got a good match with experimental measurements.", "author_names": [ "Amit Malik", "Chandan Sharma", "Robert Laishram", "Rajesh K Bag", "D S Rawal", "Seema Vinayak", "R K Sharma" ], "corpus_id": 103685805, "doc_id": "103685805", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Role of AlGaN/GaN interface traps on negative threshold voltage shift in AlGaN/GaN HEMT", "venue": "", "year": 2018 }, { "abstract": "", "author_names": [ "Takaya Nagai" ], "corpus_id": 115051025, "doc_id": "115051025", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Diode Operation in Normally off GaN HEMT with High Controllability of Threshold Voltage", "venue": "", "year": 2015 } ]

[ { "abstract": "Atomically thin two dimensional semiconductors such as MoS2 hold great promise for electrical, optical and mechanical devices and display novel physical phenomena. However, the electron mobility of mono and few layer MoS2 has so far been substantially below theoretically predicted limits, which has hampered efforts to observe its intrinsic quantum transport behaviours. Potential sources of disorder and scattering include defects such as sulphur vacancies in the MoS2 itself as well as extrinsic sources such as charged impurities and remote optical phonons from oxide dielectrics. To reduce extrinsic scattering, we have developed here a van der Waals heterostructure device platform where MoS2 layers are fully encapsulated within hexagonal boron nitride and electrically contacted in a multi terminal geometry using gate tunable graphene electrodes. Magneto transport measurements show dramatic improvements in performance, including a record high Hall mobility reaching 34,000 cm(2) V( 1) s( 1) for six layer MoS2 at low temperature, confirming that low temperature performance in previous studies was limited by extrinsic interfacial impurities rather than bulk defects in the MoS2. We also observed Shubnikov de Haas oscillations in high mobility monolayer and few layer MoS2. Modelling of potential scattering sources and quantum lifetime analysis indicate that a combination of short range and long range interfacial scattering limits the low temperature mobility of MoS2.", "author_names": [ "Xu Cui", "Gwan-Hyoung Lee", "Young Duck Kim", "Ghidewon Arefe", "Pinshane Y Huang", "Chul-Ho Lee", "Daniel A Chenet", "Xian Zhang", "Lei Wang", "Fan Ye", "Filippo Pizzocchero", "Bjarke S Jessen", "Kenji Watanabe", "Takashi Taniguchi", "David A Muller", "Tony Low", "Philip Kim", "James C Hone" ], "corpus_id": 11005492, "doc_id": "11005492", "n_citations": 804, "n_key_citations": 10, "score": 1, "title": "Multi terminal transport measurements of MoS2 using a van der Waals heterostructure device platform.", "venue": "Nature nanotechnology", "year": 2015 }, { "abstract": "Atomically thin two dimensional (2D) semiconductors such as molybdenum disulphide (MoS2) hold great promise in electrical, optical, and mechanical devices and display novel physical phenomena such as coupled spin valley physics and the valley Hall effect. However, the electron mobility of mono and few layer MoS2 has so far been substantially below theoretically predicted limits, particularly at low temperature (T) which has hampered efforts to observe its intrinsic quantum transport behaviors. Potential sources of disorder and scattering include both defects such as sulfur vacancies in the MoS2 itself, and extrinsic sources such as charged impurities and remote optical phonons from oxide dielectrics. To reduce extrinsic scattering and approach the intrinsic limit, we developed a van der Waals (vdW) heterostructure device platform where MoS2 layers are fully encapsulated within hexagonal boron nitride (hBN) and electrically contacted in a multi terminal geometry using gate tunable graphene electrodes. Multi terminal magneto transport measurements show dramatic improvements in performance, including a record high Hall mobility reaching 34,000 cm2/Vs for 6 layer MoS2 at low T. Comparison to theory shows a decrease of 1 2 orders of magnitude in the density of charged impurities, indicating that performance at low T in previous studies was limited by extrinsic factors rather than defects in the MoS2. We also observed Shubnikov de Haas (SdH) oscillations for the first time in high mobility monolayer and few layer MoS2. This novel device platform therefore opens up a new way toward measurements of intrinsic properties and the study of quantum transport phenomena in 2D semiconducting materials.", "author_names": [ "Xu Cui", "Gwan-Hyoung Lee", "Young Duck Kim", "Ghidewon Arefe", "Pinshane Y Huang", "Chul-Ho Lee", "Daniel A Chenet", "Xian Zhang", "Lei Wang", "Fan Ye", "Filippo Pizzocchero", "Bjarke S Jessen", "Kenji Watanabe", "Takashi Taniguchi", "David A Muller", "Tony Low", "Philip Kim", "James C Hone" ], "corpus_id": 118449551, "doc_id": "118449551", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Multi terminal electrical transport measurements of molybdenum disulphide using van der Waals heterostructure device platform", "venue": "", "year": 2014 }, { "abstract": "Valleytronics is an appealing alternative to conventional charge based electronics that aims at encoding data in the valley degree of freedom, that is, the information as to which extreme of the conduction or valence band carriers are occupying. The ability to create and control valley currents in solid state devices could therefore enable new paradigms for information processing. Transition metal dichalcogenides (TMDCs) are a promising platform for valleytronics due to the presence of two inequivalent valleys with spin valley locking1 and a direct bandgap2,3, which allows optical initialization and readout of the valley state4,5. Recent progress on the control of interlayer excitons in these materials6 8 could offer an effective way to realize optoelectronic devices based on the valley degree of freedom. Here, we show the generation and transport over mesoscopic distances of valley polarized excitons in a device based on a type II TMDC heterostructure. Engineering of the interlayer coupling results in enhanced diffusion of valley polarized excitons, which can be controlled and switched electrically. Furthermore, using electrostatic traps, we can increase the exciton concentration by an order of magnitude, reaching densities in the order of 1012 cm 2, opening the route to achieving a coherent quantum state of valley polarized excitons via Bose Einstein condensation.Engineering the interlayer coupling in a van der Waals heterostructure enables electrical control over the transport and density of valley polarized interlayer excitons.", "author_names": [ "Dmitrii Unuchek", "Alberto Ciarrocchi", "Ahmet Avsar", "Zhe Sun", "Kenji Watanabe", "Takashi Taniguchi", "Andras Kis" ], "corpus_id": 204812649, "doc_id": "204812649", "n_citations": 45, "n_key_citations": 0, "score": 0, "title": "Valley polarized exciton currents in a van der Waals heterostructure", "venue": "Nature Nanotechnology", "year": 2019 }, { "abstract": "The promise of high density and low energy consumption devices motivates the search for layered structures that stabilize chiral spin textures such as topologically protected skyrmions. At the same time, layered structures provide a new platform for the discovery of new physics and effects. Recently discovered long range intrinsic magnetic orders in the two dimensional van der Waals materials offer new opportunities. Here we demonstrate the Dzyaloshinskii Moriya interaction and Neel type skyrmions are induced at the WTe2/Fe3GeTe2 interface. Fe3GeTe2 is a ferromagnetic material with strong perpendicular magnetic anisotropy. We demonstrate that the strong spin orbit interaction in 1T' WTe2 does induce a large interfacial Dzyaloshinskii Moriya interaction at the interface with Fe3GeTe2 due to the inversion symmetry breaking to stabilize skyrmions. Transport measurements show the topological Hall effect in this heterostructure for temperatures below 100 K. Furthermore, Lorentz transmission electron microscopy is used to directly image Neel type skyrmions along with aligned and stripe like domain structure. This interfacial coupling induced Dzyaloshinskii Moriya interaction is estimated to have a large energy of 1.0 mJ/m^2, which can stabilize the Neel type skyrmions in this heterostructure. This work paves a path towards the skyrmionic devices based on van der Waals heterostructures.", "author_names": [ "Yingying Wu", "Senfu Zhang", "Junwei Zhang", "Wei Wang", "Yang Zhu", "Jin Hu", "Kin Wong", "Chi Fang", "Caihua Wan", "Xiufeng Han", "Qiming Shao", "Takashi Taniguchi", "Kenji Watanabe", "Zhiqiang Mao", "Xixiang Zhang", "Kang L Wang" ], "corpus_id": 198953431, "doc_id": "198953431", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "N\\'eel type skyrmion in WTe2/Fe3GeTe2 van der Waals heterostructure.", "venue": "", "year": 2019 }, { "abstract": "The optical and electronic properties of van der Waals (vdW) heterostructures depend strongly on the atomic stacking order of the constituent layers. This is exemplified by periodic variation of the local atomic registry, known as moire patterns, giving rise to superconductivity and ferromagnetism in twisted bilayer graphene and novel exciton states in transition metal dichalcogenides (TMD) heterobilayers. However, the presence of the nanometer scale moire superlattices is typically deduced indirectly, because conventional imaging techniques, such as transmission electron microscopy (TEM) require special sample preparation that is incompatible with most optical and transport measurements. Here, we demonstrate a method that uses a secondary electron microscope to directly image the local stacking order in fully hexagonal boron nitride (hBN) encapsulated, gated vdW heterostructure devices on standard Si substrates. Using this method, we demonstrate imaging of reconstructed moire patterns in stacked TMDs, ABC/ABA stacking order in graphene multilayers, and AB/BA boundaries in bilayer graphene. Furthermore, we show that the technique is non destructive, thus unlocking the possibility of directly correlating local stacking order with optical and electronic properties, crucial to the development of vdW heterostructure devices with precisely controlled functionality.", "author_names": [ "Andrey Sushko", "Kristiaan De Greve", "Trond I Andersen", "Giovanni Scuri", "You Zhou", "Ji Ho Sung", "Kenji Watanabe", "Takashi Taniguchi", "Philip Kim", "Hongkun Park", "Mikhail D Lukin" ], "corpus_id": 209376739, "doc_id": "209376739", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "High resolution imaging of reconstructed domains and moire patterns in functional van der Waals heterostructure devices.", "venue": "", "year": 2019 }, { "abstract": "The recently discovered two dimensional materials can be used to fabricate multilayer heterostructures. Interlayer charge transfer is a key process in such heterostructures as it can enable emergent optoelectronic properties. Efficient interlayer charge transfer in van der Waals heterostructures has been observed by femtosecond transient absorption and steady state optical spectroscopy measurements, based on measuring the interlayer carrier distribution. Here, we show that a second harmonic generation process allows direct probing of the electric field induced by the charge transfer. An ultrashort laser pulse was used to excite electrons and holes in a MoS2/WS2 heterostructure. The separation of the electrons and holes from the two monolayers generates an electric field, which enables the generation of the second harmonic of an incident fundamental pulse. We further studied the time evolution of this electric field by measuring the second harmonic signal as a function of the time delay between the pump and the fundamental pulses. The result agrees well with the dynamics revealed by a transient absorption measurement. These results provide direct evidence of interlayer charge transfer and demonstrate an all optical method of studying charge transfer and induced electric fields in two dimensional materials. Furthermore, this effect, if large enough, could be utilized in optical devices based on 2D heterostructures with nonlinear optical responses controllable by interlayer charge transfer.", "author_names": [ "Peng Yao", "Da-wei He", "Peymon Zereshki", "Yongsheng Wang", "Hui Zhao" ], "corpus_id": 213545328, "doc_id": "213545328", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Nonlinear optical effect of interlayer charge transfer in a van der Waals heterostructure", "venue": "Applied Physics Letters", "year": 2019 }, { "abstract": "Two dimensional (2D) material based heterostructures provide a unique platform where interactions between stacked 2D layers can enhance the electrical and opto electrical properties as well as give rise to interesting new phenomena. Here, the operation of a van der Waals heterostructure device comprising of vertically stacked bilayer MoS2 and few layered WSe2 has been demonstrated in which an atomically thin MoS2 layer has been employed as a tunneling layer to the underlying WSe2 layer. In this way, simultaneous contacts to both MoS2 and WSe2 2D layers have been established by forming a direct metal semiconductor to MoS2 and a tunneling based metal insulator semiconductor contacts to WSe2, respectively. The use of MoS2 as a dielectric tunneling layer results in an improved contact resistance (80 kO mm) for WSe2 contact, which is attributed to reduction in the effective Schottky barrier height and is also confirmed from the temperature dependent measurement. Furthermore, this unique contact engineering and type II band alignment between MoS2 and WSe2 enables a selective and independent carrier transport across the respective layers. This contact engineered dual channel heterostructure exhibits an excellent gate control and both channel current and carrier types can be modulated by the vertical electric field of the gate electrode, which is also reflected in the on/off ratio of 104 for both electron (MoS2) and hole (WSe2) channels. Moreover, the charge transfer at the heterointerface is studied quantitatively from the shift in the threshold voltage of the pristine MoS2 and the heterostructure device, which agrees with the carrier recombination induced optical quenching as observed in the Raman spectra of the pristine and heterostructure layers. This observation of dual channel ambipolar transport enabled by the hybrid tunneling contacts and strong interlayer coupling can be utilized for high performance opto electrical devices and applications.", "author_names": [ "Muhammad Atif Khan", "Servin Rathi", "Changhee Lee", "Dongsuk Lim", "Yunseob Kim", "Sun Jin Yun", "Doo-Hyeb Youn", "Gil-Ho Kim" ], "corpus_id": 49412258, "doc_id": "49412258", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Tunable Electron and Hole Injection Enabled by Atomically Thin Tunneling Layer for Improved Contact Resistance and Dual Channel Transport in MoS2/WSe2 van der Waals Heterostructure.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "Utilizing spin or valley degree of freedom is one of the promising approaches to realize more energy efficient information processing. In the 2D transition metal dichalcogenide, the spin/valley current can be generated by utilizing the circular photogalvanic effect (CPGE) i.e. the generation of photocurrent by a circularly polarized light. Here we show that an in plane electric field at MoS2/WSe2 heterostructure electrode boundary results in an electrically tunable circular photogalvanic effect (CPGE) under optical excitation with normal incidence. The observed CPGE can be explained by the valence band shift due to the in plane electric field and different effective relaxation times between hole and electron combined with the valley optical selection rule. Furthermore, we show that the CPGE can be controlled by changing the Fermi level using an out of plane electric field. Such phenomena persist even at room temperature. This finding may facilitate the utilization of 2D heterostructure as an opto valleytronics and opto spintronics device platform.", "author_names": [ "Abdullah Rasmita", "Chongyun Jiang", "Hui Ma", "Zhurun Ji", "Ritesh Agarwal", "Wei-bo Gao" ], "corpus_id": 204939690, "doc_id": "204939690", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Circular photogalvanic effect in 2D van der Waals heterostructure", "venue": "", "year": 2019 }, { "abstract": "Van der Waals heterostructures (vdWHs) based on two dimensional (2D) materials are being studied extensively for their prospective applications in photodetectors. As the pristine WSe2/MoTe2 heterostructure is a type I (straddling gap) structure, it cannot be used as a photovoltaic device theoretically, although both WSe2 and MoTe2 have excellent photoelectric properties. The Fermi level of p doped WSe2 is close to its valence band. The p doped WSe2/MoTe2 heterostructure can perform as a photovoltaic device because a built in electric field appears at the interface between MoTe2 and p doped WSe2. Here, a 633 nm laser was used for scanning the surface of WSe2 in order to obtain the p doped WSe2. X ray photoelectron spectroscopy (XPS) and electrical measurements verified that p type doping in WSe2 is produced through laser treatment. The p type doping in WSe2 includes substoichiometric WOx and nonstoichiometric WSex. A photovoltaic device using p doped WSe2 and MoTe2 was successfully fabricated. The band structure, light matter reactions, and carrier transport in the p doped WSe2/MoTe2 heterojunction were analyzed. The results showed that this photodetector has an on/off ratio of 104, dark current of 1 pA, and response time of 72 ms under the illumination of 633 nm laser at zero bias (Vds 0 V) The proposed p doping method may provide a new approach to improve the performance of nanoscale optoelectronic devices.", "author_names": [ "Jing Chen", "Yabing Shan", "Qiyuan Wang", "Junqiang Zhu", "Ran Liu" ], "corpus_id": 215615715, "doc_id": "215615715", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "P type laser doped WSe2/MoTe2 van der Waals heterostructure photodetector.", "venue": "Nanotechnology", "year": 2020 }, { "abstract": "Two dimensional van der Waals heterostructures (vdWHs) have attracted considerable interest 1 4 However, most vdWHs reported so far are created by an arduous micromechanical exfoliation and manual restacking process 5 which although versatile for proof of concept demonstrations 6 16 and fundamental studies 17 30 is clearly not scalable for practical technologies. Here we report a general synthetic strategy for two dimensional vdWH arrays between metallic transition metal dichalcogenides (m TMDs) and semiconducting TMDs (s TMDs) By selectively patterning nucleation sites on monolayer or bilayer s TMDs, we precisely control the nucleation and growth of diverse m TMDs with designable periodic arrangements and tunable lateral dimensions at the predesignated spatial locations, producing a series of vdWH arrays, including VSe 2 /WSe 2 NiTe 2 /WSe 2 CoTe 2 /WSe 2 NbTe 2 /WSe 2 VS 2 /WSe 2 VSe 2 /MoS 2 and VSe 2 /WS 2 Systematic scanning transmission electron microscopy studies reveal nearly ideal vdW interfaces with widely tunable moire superlattices. With the atomically clean vdW interface, we further show that the m TMDs function as highly reliable synthetic vdW contacts for the underlying WSe 2 with excellent device performance and yield, delivering a high ON current density of up to 900 microamperes per micrometre in bilayer WSe 2 transistors. This general synthesis of diverse two dimensional vdWH arrays provides a versatile material platform for exploring exotic physics and promises a scalable pathway to high performance devices. A general strategy for the synthesis of two dimensional van der Waals heterostructure arrays is used to produce high performance electronic devices, showing the potential of this scalable approach for practical technologies.", "author_names": [ "Jia Li", "Xiangdong Yang", "Yang Liu", "Bolong Huang", "Ruixia Wu", "Zhengwei Zhang", "Bei Zhao", "Huifang Ma", "Weiqi Dang", "Zheng Wei", "Kai Wang", "Zhaoyang Lin", "Xingxu Yan", "Mingzi Sun", "Bo Li", "Xiaoqing Pan", "Jun Luo", "Guangyu Zhang", "Yuan Liu", "Yu Huang", "Xidong Duan", "Xiangfeng Duan" ], "corpus_id": 212670163, "doc_id": "212670163", "n_citations": 87, "n_key_citations": 1, "score": 0, "title": "General synthesis of two dimensional van der Waals heterostructure arrays", "venue": "Nature", "year": 2020 } ]

[ { "abstract": "Inorganic nanomaterials can combine advantages typical for organic semiconductors, especially the fabrication by simple solution processes, and the high performance associated with inorganic semiconductors. In this work, we investigate the integration of such nanomaterials into solution processed, organic inorganic thin film solar cells and light emitting diodes. For this surface functionalized silicon quantum dots serve as active materials for light emission and absorption, spray deposited metal nanowires from silver and copper as transparent conductive electrodes.", "author_names": [ "Matthias Loch" ], "corpus_id": 198392670, "doc_id": "198392670", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nanomaterials for hybrid organic inorganic optoelectronic devices processed from solution", "venue": "", "year": 2019 }, { "abstract": "In this work, the influence of electrodes' distance upon the properties of amorphous silicon (a Si:H) deposited by plasmaenhanced chemical vapor deposition method on both intrinsic and doped a Si:H films is investigated in terms of their electrical, optical, and structural characteristics. For this purpose, Fouriertransform infra red and secondary ion mass spectroscopy as well as photoconductance decay, spectral ellipsometry, and conductivity measurements are employed. Electrodes' distance is varied from 20 to 120mm. Regarding the passivation quality of the a Si: H film an optimum electrodes' distance of 60mm is found. In addition, electrodes' distance is detected to have a great influence on the accelerated initial growth rate, which strongly diminishes with increasing distance. Thus, electrodes' distance also determines the overall thickness of thin intrinsic a Si:H films being particularly interesting for utilization in heterojunction solar cells. With doped a Si:H films, however, electrodes' distance influences mainly the dopant concentration in the films and therewith their conductivity.", "author_names": [ "Nils Brinkmann", "Angelika Gorgulla", "Anja Bauer", "Daniel Skorka", "Gabriel Micard", "Giso Hahn", "Barbara Terheiden" ], "corpus_id": 53372391, "doc_id": "53372391", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "In fl uence of electrodes distance upon properties of intrinsic and doped amorphous silicon fi lms for heterojunction solar cells", "venue": "", "year": 2018 }, { "abstract": "In order to reduce the solar cell price, the active layer thickness has been decreased, but this reduces the absorption of light, especially at high wavelengths. One of the ways to increase the absorption and efficiency of solar cells is to use metal nanoparticles and to benefit from the effect of surface plasmon resonance. In this paper, we have tried to increase the absorption and efficiency of the solar cell by placing the silver nanoparticles on zinc oxide (ZnO) layer in a solar cell with an activate layer of amorphous silicon (a Si) Also, compared to rectangular, triangular and semi cylindrical arrays, it is shown that silver nanoparticles will increase the efficiency further. Finally, the basic parameters of the proposed solar cell are examined.", "author_names": [ "Fatemeh Mohammad Jafari", "Mohammad Reza Rakhshani", "Mohammad ali Mansoori birjandi" ], "corpus_id": 195724604, "doc_id": "195724604", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Efficiency Enhancement in Thin Film Silicon Solar Cell Using the Plasmonic Properties of Metals", "venue": "", "year": 2019 }, { "abstract": "This work reports on developments in the field of wide band gap Cu2ZnXY4 (with X Sn, Si or Ge, and Y S, Se) kesterite thin film solar cells. An overview on recent developments and the current understanding of wide band gap kesterite absorber layers, alternative buffer layers, and suitable transparent back contacts is presented. Cu2ZnGe(S,Se)4 absorbers with absorber band gaps up to 1.7 eV have been successfully developed and integrated into solar cells. Combining a CdS buffer layer prepared by an optimized chemical bath deposition process with a 1.36 eV band gap absorber resulted in a record Cu2ZnGeSe4 cell efficiency of 7.6% while the highest open circuit voltage of 730 mV could be obtained for a 1.54 eV band gap absorber and a Zn(O,S) buffer layer. Employing InZnOx or TiO2 protective top layers on SnO2:In transparent back contacts yields 85 90% of the solar cell performance of reference cells (with Mo back contact) These advances show the potential as well as the challenges of wide band gap kesterites for future applications in high efficiency and low cost tandem photovoltaic devices.", "author_names": [ "Bart Vermang", "Guy Brammertz", "Marc Meuris", "Thomas Schnabel", "Erik Ahlswede", "Leo Choubrac", "Sylvie Harel", "Christophe Cardinaud", "Ludovic Arzel", "Nicolas Barreau", "Joop van Deelen", "P J Bolt", "Patrice Bras", "Yi Ren", "E Jaremalm", "Samira Khelifi", "Sheng Yang", "J Lauwaert", "Maria Batuk", "Joke Hadermann", "Xeniya Kozina", "Evelyn Handick", "Claudia Hartmann", "Daniela Gerlach", "A Matsuda", "Shigenori Ueda", "Toyohiro Chikyow", "Roberto Felix", "Yufeng Zhang", "Regan G Wilks", "Marcus Bar" ], "corpus_id": 197619285, "doc_id": "197619285", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Wide band gap kesterite absorbers for thin film solar cells: potential and challenges for their deployment in tandem devices", "venue": "", "year": 2019 }, { "abstract": "The application of thinner cadmium sulfide (CdS) window layer is a feasible approach to improve the performance of cadmium telluride (CdTe) thin film solar cells. However, the reduction of compactness and continuity of thinner CdS always deteriorates the device performance. In this work, transparent Al 2 O 3 films with different thicknesses, deposited by using atomic layer deposition (ALD) were utilized as buffer layers between the front electrode transparent conductive oxide (TCO) and CdS layers to solve this problem, and then, thin film solar cells with a structure of TCO/Al 2 O 3 /CdS/CdTe/BC/Ni were fabricated. The characteristics of the ALD Al 2 O 3 films were studied by UV visible transmittance spectrum, Raman spectroscopy, and atomic force microscopy (AFM) The light and dark J V performances of solar cells were also measured by specific instrumentations. The transmittance measurement conducted on the TCO/Al 2 O 3 films verified that the transmittance of TCO/Al 2 O 3 were comparable to that of single TCO layer, meaning that no extra absorption loss occurred when Al 2 O 3 buffer layers were introduced into cells. Furthermore, due to the advantages of the ALD method, the ALD Al 2 O 3 buffer layers formed an extremely continuous and uniform coverage on the substrates to effectively fill and block the tiny leakage channels in CdS/CdTe polycrystalline films and improve the characteristics of the interface between TCO and CdS. However, as the thickness of alumina increased, the negative effects of cells were gradually exposed, especially the increase of the series resistance (R s and the more serious \"roll over\" phenomenon. Finally, the cell conversion efficiency (e) of more than 13.0% accompanied by optimized uniformity performances was successfully achieved corresponding to the 10 nm thick ALD Al 2 O 3 thin film.", "author_names": [ "Guanggen Zeng", "Xia Hao", "Shengqiang Ren", "Lianghuan Feng", "Qionghua Wang" ], "corpus_id": 85524254, "doc_id": "85524254", "n_citations": 41, "n_key_citations": 0, "score": 0, "title": "Application of ALD Al 2 O 3 in CdS/CdTe Thin Film Solar Cells", "venue": "", "year": 2019 }, { "abstract": "Thin film technology has a world wide reputation in the field of thin film deposition process and also it paves a way for innovative techniques in large scale applications. Modern thin film technology has evolved into a sophisticated way to increase the performance and esthetic value for making new functional devices. One such application is search of new materials for thin film solar cells as it provides the solution for the today's concern of energy crisis. Depending on the processing technology solar cells are of various types. Among them, silicon wafer solar cells and thin film solar cells are most promising. Thin film technology has made solar cells more feasible to be employed in terms of device design and fabrication. The efficiencies produced by these solar cells still need to be improved. For this many investigations for further improvement from CIGS (copper indium gallium selenide) solar cell to dye sensitized solar cells and perovskite solar cells. Due to toxic nature and environmental impact the use of lead in perovskite solar cells are replaced by tin or some materials which would equalize the achieved efficiency of lead. Hence the developments in search of innovative materials continue its path in thin film solar cells to develop the photovoltaic field by enhancing its efficiency.", "author_names": [ "Senthil T S", "Kalaiselvi C R" ], "corpus_id": 139825122, "doc_id": "139825122", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "New Materials for Thin Film Solar Cells", "venue": "", "year": 2019 }, { "abstract": "Here we report highly efficient, indium tin oxide (ITO) free polymer solar cells (PSCs) with an ultrathin copper (Cu) film(~10 nm) coated with a thin layer of poly[(9,9 bis(3' (N,N dimethylamino)propyl) 2,7 fluorene) alt 2,7 (9,9 dioctylfluorene) (PFN) as transparent electrode. Despite of its lower far field transmittance of the electrode, the obtained ITO free device based on the ultrathin Cu film can delivery higher absorption efficiency than that of the device based on ITO substrate in the long wavelength region, which can be attributed to the formation of metal resonant microcavity between the opaque back metal mirror (MoO3/Al electrode) and the transparent Cu film with high reflectance. As a result, polymer solar cells based on poly[[2,6' 4,8 di(5 ethylhexylthienyl)benzo[1,2 b;3,3 b]dithiophene][3 fluoro 2[(2 ethylhexyl)carbonyl]thieno[3,4 b]thiophenediyl] (PTB7 Th) and [6,6] phenyl C71 butyric acid methyl ester (PC71BM) blend show a high power conversion efficiency (PCE) of 8.21 comparable to that of the control device based on ITO electrode (with a PCE of 9.60% The results demonstrate that thermally evaporated Cu thin film electrode can be promising candidate to replace ITO for highly efficient PSCs, thus may open up the possibility for massive production of PSCs with low cost.", "author_names": [ "Quanbin Liang", "Guoping Luo", "Xiaoping Cheng", "Hongbin Wu" ], "corpus_id": 207969871, "doc_id": "207969871", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Highly Efficient, ITO Free Polymer Solar Cells Using Ultrathin Copper Film as Transparent Electrode", "venue": "", "year": 2019 }, { "abstract": "In this study, p type amorphous silicon oxide (a SiOx) films are deposited using a radio frequency inductively coupled plasma chemical vapor deposition system. Effects of the CO2 gas flow rate on film properties and crystalline silicon heterojunction (HJ) solar cell performance are investigated. The experimental results show that the band gap of the a SiOx film can reach 2.1 eV at CO2 flow rate of 10 standard cubic centimeters per minute (sccm) but the conductivity of the film deteriorates. In the device simulation, the transparent conducting oxide and contact resistance are not taken into account. The electrodes are assumed to be perfectly conductive and transparent. The simulation result shows that there is a tradeoff between the increase in the band gap and the reduction in conductivity at increasing CO2 flow rate, and the balance occurs at the flow rate of six sccm, corresponding to a band gap of 1.95 eV, an oxygen content of 34% and a conductivity of 3.3 S/cm. The best simulated conversion efficiency is 25.58% with an open circuit voltage of 741 mV, a short circuit current density of 42.3 mA/cm2, and a fill factor of 0.816%", "author_names": [ "Chia-Hsun Hsu", "Xiao-Ying Zhang", "Hai-jun Lin", "Shui-Yang Lien", "Yun-Shao Cho", "Chang-Sin Ye" ], "corpus_id": 198486653, "doc_id": "198486653", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Numerical Simulation of Crystalline Silicon Heterojunction Solar Cells with Different p Type a SiOx Window Layer", "venue": "Energies", "year": 2019 }, { "abstract": "Thin film solar cells are desirable due to minimal material usage, cost effective synthesis processes and a promising trend in efficiency rise. In this review paper, remarkable progresses of five major types of thin film solar cell (TFSC) including amorphous silicon (a Si) solar cell, copper indium gallium selenide (CIGS) solar cell, copper zinc tin sulfide (CZTS) solar cell, cadmium telluride (CdTe) solar cell and dye sensitized solar cell (DSSC) have been presented from their inception to the state of the art development. Cell configurations, different layers of these cells, their growth procedures, function and modification for working solar cells have also been explored. Critical issues that limit the performance of these cells as well as current scenario have also been addressed. Finally, a summary of this work has been presented as a comparative study among the five major types of TFSCs in terms of the state of the art data for structural, optical, and electrical properties, material availability, toxicity, stability and highest efficiency for helping readers decipher the major challenges for popularization and commercialization of this technology.", "author_names": [ "Abu Kowsar", "Syed Farid Uddin Farhad", "Mashudur Rahaman", "Md Saidul Islam", "Abdullah Yousuf Imam", "Sumon Chandra Debnath", "Munira Sultana", "Md Azizul Hoque", "Afrina Sharmin", "Zahid Hasan Mahmood" ], "corpus_id": 198861372, "doc_id": "198861372", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Progress in Major Thin film Solar Cells: Growth Technologies, Layer Materials and Efficiencies", "venue": "", "year": 2019 }, { "abstract": "In this thesis, we present the development and characterization of novel approaches to carrier selective passivating contacts for crystalline silicon (c Si) solar cells. In our first approach, we benefit from a wide bandgap material, namely mixed phase silicon oxide (SiOX) High hydrogen dilution during the plasma enhanced chemical vapor deposition of a SiOX layer leads to the growth of vertically oriented silicon filaments embedded in a silicon oxide matrix. The resulting mixed phase material combines transparency and vertical conduction through the layer. We propose a layered contact structure starting with an ultra thin chemically grown SiOX 1.2nm) at the c Si wafer surface, followed by a phosphorus doped bilayer of the mixed phase SiOX, finishing with a nanocrystalline silicon layer that ensures contact with the metallization. With such a stack, an electron selective passivating contact with a saturation current density J0 of 5.3 fA/cm2 is achieved on n type wafers with hydrogenation, whereas on p type wafers the contact reached 5.8 fA/cm2 even without hydrogenation. The contact is analyzed in detail with respect to its structure and its change upon thermal treatment. Two different growth regions are detected: one with the vertically oriented silicon inclusions and a second one in which the silicon phases have more lateral growth. Crystallization and atomic redistribution are analyzed during in situ annealing in an electron microscope, leading to a better understanding of the change in distribution of phosphorus and oxygen as well as the nucleation sites. The influence of the annealing temperatures and dwell times as well as the initial doping concentration on the resulting in diffused region and the passivation quality is reported. We use simulations to relate the influence of these parameters on passivation to the different recombination mechanisms. From the analyzed phosphorus doping profiles, an interesting observation is reported. The chemical oxide varies in thickness and density depending on the wafer polarity as well as the base resistivity. Proof of concept cells including this novel structure demonstrate the suitability for electron selective passivating contacts at the device level with conversion efficiencies of 19.0% on planar wafers and 20.1% on textured wafers. Promisingly high short circuit current densities (JSC) of 35 mA/cm2 (40 mA/cm2) on planar (textured) with low parasitic absorption indicate its potential as a front contact in next generation solar cells. Additionally, the beneficial feature of the smooth refractive index change within the layers that leads to a low reflectance over a broad wavelength range, similar to a built in anti reflection coating, is presented. A second approach to reach highly transparent electron selective passivating contacts is", "author_names": [ "Josua A Stuckelberger" ], "corpus_id": 105481141, "doc_id": "105481141", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Transparent Passivating Contacts for Front Side Application in Crystalline Silicon Solar Cells", "venue": "", "year": 2018 } ]

[ { "abstract": "Abstract The steady state gas sensing characteristics of SnO2 gas sensors, as exemplified by the Taguchi Gas Sensor (TGS) are comprehensively studied. Resistance responses to hydrogen, methane, carbon monoxide and water vapor are experimentally characterized, with particular emphasis on multiple gas interactions. We find that the presence of ambient oxygen is essential to the sensor's operation and that the detection of combustible or reducing gas is mediated by reaction with adsorbed oxygen on the sensor surface. A quantitative model of device operation is constructed which unifies the diverse properties of the TGS and other semiconductor sensors. The model supplies the mathematical framework for meaningful comparisons of sensor performances and gas sensitivities. In addition, it provides for the intrinsic power law response of sensor electrical resistance to combustible gas concentrations, the competitive and synergistic interactions of several gases detected simultaneously, and the source of sensor unselectivity. Stoichiometries and activation energies for the pertinent oxidation reactions on the tin oxide sensor surface can be derived from a sensor's resistance response by curve fitting to the mathematical model.", "author_names": [ "P K Clifford", "David T Tuma" ], "corpus_id": 93683479, "doc_id": "93683479", "n_citations": 241, "n_key_citations": 1, "score": 1, "title": "Characteristics of semiconductor gas sensors I. Steady state gas response", "venue": "", "year": 1982 }, { "abstract": "The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient distributed oxygen vacancy was proposed based on the effects of cooling rate and re annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady state and transient state oxygen vacancy distributions, which were used to calculate the gas sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.", "author_names": [ "Jianqiao Liu", "Yinglin Gao", "Xuekui Ed Wu", "Guohua Jin", "Zhaoxia Zhai", "Huan Liu" ], "corpus_id": 3523567, "doc_id": "3523567", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics", "venue": "Sensors", "year": 2017 }, { "abstract": "The grain size effects on gas sensing characteristics of semiconductor gas sensor are simulated based on the model of gradient distributed oxygen vacancies, which describes the dynamics of oxygen vacancies in an idealized cooling process. Sensor resistance and response to oxidizing gases, as functions of grain size (RC) and depletion layer width (w) are calculated from the steady state vacancy distribution in the depletion layer through Poissons equation. Simulation curves are plotted to fit the experimental data from WO3 and In2O3 sensors in nitrogen oxides detection. The fitting results illustrate the applicability of the model on quantitative interpretation of the grain size effects on oxidizing gas detection. The widths of depletion layer in WO3 and In2O3 nanograins are estimated.", "author_names": [ "Jian Qiao Liu", "Lin Quan" ], "corpus_id": 97975984, "doc_id": "97975984", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Simulation of Grain Size Effects on Gas Sensing Characteristics of Semiconductor Sensors in Nitrogen Oxides Detection", "venue": "", "year": 2014 }, { "abstract": "The recent advent of integrated gas sensors and advances in pattern recognition techniques have heralded a renewed interest in the electrical characteristics of porous thick semiconductor layers. A linear diffusion reaction model is considered here that may be used to characterise the transient and steady state response of several metal semiconductor metal devices. This approach differs from that of chemical kinematics which is widely adopted and focuses upon the relationship between electrical conductance and the geometrical structure of the device. The theoretical transient response is derived for several MSM device configurations and compared with experimental data on SnO2 gas sensors. There is reasonable agreement with the model predictions at low gas concentrations. Consequently, the electrical conductivity of thick porous tin oxide gas sensors is diffusion limited as the reaction rate is fast compared with the diffusion rate. However, further work is needed to address nonlinear adsorption processes and to consider a diffusion reaction process where the reaction rate is slow compared with physical diffusion.", "author_names": [ "Julian William Gardner" ], "corpus_id": 96940995, "doc_id": "96940995", "n_citations": 64, "n_key_citations": 0, "score": 0, "title": "A diffusion reaction model of electrical conduction in tin oxide gas sensors", "venue": "", "year": 1989 }, { "abstract": "A mixed potential, electrochemical sensor platform is extended to NH3 sensing by the introduction of a new gold alloy working electrode. A planar, pre commercial NH3 sensor utilized LANL's controlled interface approach, and a Pd Au alloy working electrode was tested in exhaust of a GM 1.9 L diesel engine downstream of a diesel oxidation catalyst through a slipstream arrangement. A fraction of the exhaust was pulled across the sensor with a pump at 20 L/min. In order to simulate NH3 slip inside of a full SCR emissions control system, NH3 was injected immediately upstream of the sensor using a calibrated mass flow controller. The sensor response quantitatively tracked the NH3 as measured via Fourier transform infrared (FTIR) analyzer. A calibration curve was obtained in the exhaust from an ammonia staircase response with the engine running at steady state engine conditions resulting in low background concentrations of NOx and HC <20 ppm) during calibration. Exhaust gas recirculation (EGR) switching and sweeps were used to evaluate the NH3 sensor response under different amounts of total background NOx. The calibration curve was used to directly compare the [NH3] calculated from sensor response to the gas phase composition measured via FTIR. In general, there was excellent quantitative agreement between the sensor response and the actual NH3 in the exhaust gas, and fast response time such that transients <5 ppm) could be easily discerned from baseline. A LANL pre commercial NOx sensor was tested simultaneously with the NH3 sensor and the extent of cross sensitivity between the two sensors will be discussed.", "author_names": [ "Eric Lanich Brosha", "Vitaly Y Prikhodko", "Cortney R Kreller", "Josh A Pihl", "Scott J Curran", "James E Parks", "Rangachary Mukundan" ], "corpus_id": 114299080, "doc_id": "114299080", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Response Characteristics of Stable Mixed Potential NH3 Sensors in Diesel Engine Exhaust", "venue": "Emission Control Science and Technology", "year": 2016 }, { "abstract": "Quantitative analysis of gases, by means of semiconductor sensor arrays and pattern recognition techniques such as artificial neural networks, has been the goal of a great deal of work over the last few years. However, the lack of selectivity, repeatability and drifts of the sensors, have limited the applications of these systems to qualitative or semi quantitative gas analysis. While the steady state response of the sensors is usually the signal to be processed in such analysis systems, our method consists of processing both, transient and steady state information. The sensor transient behaviour is characterised through the measure of its conductance rise time (Tr) when there is a step change in the gas concentration. Tr is characteristic of each gas/sensor pair, concentration independent and shows higher repeatability than the steady state measurements. An array of four thick film tin oxide gas sensors and pattern recognition techniques are used to discriminate and quantify among ethanol, toluene and o xylene [concentration range: 25, 50 and 100 ppm] A principal component analysis is carried out to show qualitatively that selectivity improves when the sensor behaviour is dynamically characterised. The steady state and transient conductance of the array components are processed with artificial neural networks. In a first stage, a feed forward back propagation trained ANN discriminates among the studied compounds. Afterwards, three separate ANN (one for each vapour) are used to quantify the previously identified compound. Processing data from the dynamic characterisation of the sensor array, considerably improves its identification performance, rising the discrimination success rate from a 66% when only steady state signals are used up to 100%", "author_names": [ "Eduard Llobet", "Jesus Brezmes", "Xavier Vilanova", "Jesus E Sueiras", "Xavier Correig" ], "corpus_id": 95782800, "doc_id": "95782800", "n_citations": 158, "n_key_citations": 5, "score": 0, "title": "Qualitative and quantitative analysis of volatile organic compounds using transient and steady state responses of a thick film tin oxide gas sensor array", "venue": "", "year": 1997 }, { "abstract": "This paper reports the influence of In2O3 film structure on gas sensing characteristics measured in steady state and transient modes. Films were deposited by spray pyrolysis from InCl3 water solutions. Correlation between gas sensing parameters and structural parameters such as film thickness (20 400 nm) grain size (10 70 nm) refractive index and film texture (I(400)/I(222) were established. It was shown that grain size and porosity are the parameters of In2O3 films that best control gas response to ozone. In the detection of reducing gases, the influence of film structure is less important. Decreases in film thickness, grain size and degree of texture are the best way to decrease time constants of the gas response of In2O3 based gas sensors.", "author_names": [ "Ghenadii Korotcenkov", "V Brinzari", "A Cerneavschi", "M Ivanov", "V Golovanov", "Albert Cornet", "Joan Ramon Morante", "Andreu Cabot", "Jordi Arbiol" ], "corpus_id": 95275307, "doc_id": "95275307", "n_citations": 148, "n_key_citations": 1, "score": 0, "title": "The influence of film structure on In2O3 gas response", "venue": "", "year": 2004 }, { "abstract": "Abstract A physicochemical model of the behavior of electrochemical gas sensors based in a solid state ion conducting electrolyte is presented and verified. The model focuses on air referenced planar sensors with a porous, diffusive layer covering one of the electrodes. By assuming hypotheses of ergodicity, ordinary diffusion, near equilibrium situation, high catalytic activity and steady state mass conservation in the system layer/electrode/electrolyte/electrode, the model describes the current voltage characteristics both in steady state as in transient conditions. Numerical simulations, including finite element modelling, are used for obtaining the model preditions for I(V) I(t) and V(t) responses in front of binary O2 N2 mixtures and multi component mixtures. The model is validated with our own designed sensors with different diffusion layers.", "author_names": [ "Carlos Lopez-Gandara", "Mireia Blanes", "Josep M Fernandez-Sanjuan", "Francisco M Ramos", "Albert Cirera" ], "corpus_id": 98222392, "doc_id": "98222392", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Modeling and Optimization of Diffusive Layers in Potentiometric and Amperometric Electrochemical Gas Sensors", "venue": "", "year": 2012 }, { "abstract": "ii Dedication..iv Acknowledgmentsv Vita..vii List of Tables.xii List of Figures..xiii Chapters: 1. Introduction1 1.1 Types of Gas Sensors..2 1.1.1 Potentiometric Gas Sensors.3 1.1.2 Amperometric Gas Sensors..5 1.1.3 Conductometric Gas Sensors..6 1.2 Metal Oxide Semiconductor Gas Sensors..8 1.2.1 Bulk Conductivity Changes.8 1.2.2 Surface Conductivity Changes..10 1.2.3 Conductivity in Polycrystalline Samples..10 1.2.4 Sensing Combustible Gases..11 1.3 Optimizing Metal Oxide Gas Sensors..12 1.3.1 Metal Oxides for Gas Sensing..12 1.3.2 Materials Preparation.13 ix 1.3.2.1 Control of Grain Size..13 1.3.2.2 Sol Gel Preparation.14 1.3.2.3 Other Powder Preparation Procedures..15 1.3.2.4 Reactively Sputtered Metal Oxides..16 1.3.2.5 Control of Film Thickness and Porosity.17 1.3.3 Metal and Metal Oxide Additives..17 1.3.3.1 Additives to Enhance Catalysis..18 1.3.3.2 Additives for Control of Particle Morphology..21 1.3.4 Sensor Arrays.22 1.4 TiO2 as Gas Sensor..24 References..26 2. TiO2 based Sensor Arrays Modeled with Nonlinear Regression Analysis.56 2.1 Experimental.59 2.1.1 Sample Preparation..59 2.1.2 Electrical Measurements and Data Analysis..61 2.2 Basis of the Regression Model.62 2.2.1 Kernel Ridge Regression..63 2.2.2 Determining the Composition of a Gas Mixture64 2.3 Model Development: Sensor Array I..66 2.4 Prediction of Gas Compositions: Sensor Array II69 2.4.1 8% CuO AL Fabrication Method Development69 2.4.2 Implementation of Sensor Array II71 2.5 Factors That Control Orthogonality.73 2.6 Limitations of Predictability75 2.7 Features of the Kernel Regression Model76 2.8 Conclusions..76 References78 x 3. Relationship Between Gas Surface Interactions and Sensor Response for TiO2 based Sensors100 3.1 Experimental..103 3.1.1 Sample Preparation..103 3.1.2 Electrical Measurements..105 3.1.3 Percent Conversion Measurements..105 3.1.4 Materials Characterization..106 3.2 Materials Fabrication and Characterization108 3.2.1 Additive Introduction by Solid State Mixing: La2O3..108 3.2.2 Additive Introduction by Solid State Mixing: La2O3 and CuO..112 3.2.3 Additive Introduction by Deposition Precipitation: Au..113 3.3 Chemical Reactivity..115 3.4 Electrical Response Characteristics..117 3.4.1 Sensor Response and Operating Temperature.119 3.4.2 Recovery Time.122 3.4.3 Sensor Response and Oxygen Concentration..123 3.5 Chemical Reactivity and Electrical Response of ALC with CH4..125 3.5.1 Chemical Reactivity with CH4.125 3.5.2 Electrical Response with CH4: Effect of Temperature and O2 Concentration..126 3.6 Anatase..128 3.6.1 Effect of Operating Temperature.128 3.6.2 Effect of Oxygen Concentration..131 3.7 Role of Additives..132 3.7.1 La2O3132 3.7.2 CuO..134 3.7.3 Au..135 3.8 Possible Additives and Their Effect on Sensor Sensitivity138 3.9 Conclusions.138", "author_names": [ "Marla Lea Frank" ], "corpus_id": 136458265, "doc_id": "136458265", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Novel strategies for design of high temperature titania based gas sensors for combustion process monitoring", "venue": "", "year": 2003 }, { "abstract": "Abstract Thin film metal oxide semiconductor (MOX) gas sensors are characterized by high sensitivity and fast response. Those characteristics make them very promising among the several existing technologies for the production of solid state gas sensors. Furthermore, by means of silicon micro machining technology, MOX sensors can be made on micro hotplates, allowing to reach very low power consumption, and the batch production guaranties a high yield. However, reproducibility and reliability are still major issues preventing the use of thin film MOX sensors in mass market applications. In this work, a wafer level fabrication process for micro machined low power consumption thin film MOX sensor arrays is reported. Different solutions for the optimization of the fabrication process are investigated, aiming to increase the reproducibility. The critical technological steps related to signal generation and acquisition, like the thin film definition and positioning and the definition of the sensing layer electrodes, have been optimized. The devices considered are 4 sensor arrays based on thin films of SnO2 deposited by a modified rheotaxial growth and thermal oxidation (M RGTO) technique on micro machined low power hotplates. The different fabrication techniques are described in detail. 45 sensors from 3 wafers, made using the different fabrication techniques, are comparatively characterized. The spread of the main sensor functional parameters values shows an evident decrease when the optimized fabrication process is used.", "author_names": [ "Ivan Elmi", "Stefano Zampolli", "Gian Carlo Cardinali" ], "corpus_id": 97047956, "doc_id": "97047956", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Optimization of a wafer level process for the fabrication of highly reproducible thin film MOX sensors", "venue": "", "year": 2008 } ]

[ { "abstract": "About the Author.Preface.Acknowledgements.1. Electrostatics and Electrothermal Physics.2. Electrothermal and Methods of Analysis ESD Models.3. Semiconductor Device Physics and ESD.4. Substrates and ESD.5. Wells and Sub collectors and ESD.6. Isolation Technology and ESD.7. Drain Engineering, Salicides and ESD.8. Dielectrics and ESD.9. Interconnects and ESD.10. Silicon on Insulator (SOI) and ESD.11. Silicon Germanium and ESD.12. Nanostructures and ESD.Index.", "author_names": [ "Steven H Voldman" ], "corpus_id": 106911787, "doc_id": "106911787", "n_citations": 71, "n_key_citations": 2, "score": 1, "title": "ESD: Physics and Devices", "venue": "", "year": 2004 }, { "abstract": "This paper revisits the physics of current filamentation in grounded gate NMOS (ggNMOS) devices and presents new physical insights which were not addressed in earlier works. A clear distinction between electrical and thermal instabilities is presented. Moreover, filament dynamics under electrical and thermal instability in both silicided and silicide blocked devices is discussed while highlighting observations which contradict with established theory of current ballasting. Interplay between electrical and thermal instabilities and its dependence on the presence or absence of silicide blocking is explored further. Filament spreading in ggNMOS devices and it is dependence on silicide blocking is discussed. Finally, while using the developed physical insights, missing correlation between TLP and HBM extracted failure current of silicided ggNMOS device is explained.", "author_names": [ "Milova Paul", "Christian C Russ", "B Sampath Kumar", "Harald Gossner", "Mayank Shrivastava" ], "corpus_id": 49268631, "doc_id": "49268631", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Physics of Current Filamentation in ggNMOS Devices Under ESD Condition Revisited", "venue": "IEEE Transactions on Electron Devices", "year": 2018 }, { "abstract": "This article provides an understanding of the transient voltage overshoot physics observed with electro static discharge (ESD) n type, p type, and n type diffusions (NPN) bipolar devices through the use of calibrated technical computer aided design (TCAD) with measured silicon results. This analysis graphically steps through each stage of the measured transient electrical response, to explain the inertia that limits the speed of the NPN ESD cell, and then uses this knowledge to provide a fully characterized silicon solution for ultrafast ESD events to achieve an 8 kV IEC61000 4 4 rating. This solution is developed by exploring five different integrated designs that are constructed on an 80 V bipolar and complimentary double diffused metal oxide semiconductor (BiCDMOS) process platform to protect against a product level 125 V voltage overshoot gate oxide ruptures as measured with a 0.6 ns rise time transmission line pulse (TLP) The fully characterized electrical results for each test overshoot structure with a fixed layout area of <inline formula> <tex math notation=\"LaTeX\"$200\\\\mu \\text{m}\\times200\\\\mu \\text{m} /tex math>/inline formula> are in parallel to NPN ESD cells arranged with two in series and two in parallel <inline formula> <tex math notation=\"LaTeX\"$200\\\\mu \\text{m}\\times 80\\\\mu \\text{m} /tex math>/inline formula> and compared in terms of the current carrying capability before the gate oxide rupture voltage of 125 V is reached. The results show that a diode engineered with a vertical breakdown achieves an ESD strength of 9.7 A before the overshoot voltage reaches the target of 125 V, resulting in a net 0.17 mA<inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m} {2} /tex math>/inline formula> The combined use of this vertical diode structure in parallel to the NPN ESD cell translates into a 7 A improvement in the strength of a conventional NPN for ultrafast timescales, which achieves the 8 kV International Electrotechnical Commission (IEC) ESD performance for this case study.", "author_names": [ "Edward Coyne", "Dave Clarke", "Stephen Heffernan", "Brian Moane" ], "corpus_id": 207829531, "doc_id": "207829531", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Designing ESD Protection Devices for Ultrafast Overvoltage Events", "venue": "IEEE Transactions on Electron Devices", "year": 2019 }, { "abstract": "Abstract In this work, we build circuit models to understand the physics of electro thermal instability and associated thermal runway in advanced ESD protection devices under filamentation. The circuit building methodology takes into account, the instability arising out of inhomogeneous triggering of 2 D planar bipolar and looks into inherent instability causing the 3 D phenomenon. Subsequently, the electro thermal coupling is analyzed to get SPICE model, as we develop a physics based methodology to comprehend the 3 D localization in the device. Furthermore, we understand the instability through appropriate modeling of localization behavior using area factor a and related electro thermal circuit models.", "author_names": [ "Dheeraj Kumar Sinha", "Amitabh Chatterjee" ], "corpus_id": 36174506, "doc_id": "36174506", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "SPICE level implementation of physics of filamentation in ESD protection devices", "venue": "Microelectron. Reliab.", "year": 2017 }, { "abstract": "Circuits design that meets various IEC electrical overstress (EOS) standards is still a challenge, for that different kinds of EOS are at different frequency bands. In this paper, a physics based transient simulation and modeling method is proposed, which can simulate wide frequency EOS including electrostatic discharge (ESD) and AC characteristics. In this method, the physical model is used to characterize the nonlinear semiconductor devices in the finite difference timedomain (FDTD) SPICE co simulation. Moreover, the modeling and physical parameters extraction method of the ESD protect devices, the transient voltage suppressor diode, is demonstrated. Taking an EOS protection circuit for example, it is modeled and simulated by the proposed method. Moreover, the circuit is also simulated by the widely used System Efficient ESD Design (SEED) method, in which the TVS diode is modeled based on 100 ns Transmission Line Pulse (TLP) measurements. The experiments show that both this method and SEED method can characterize the IEC system level ESD behaviors well. However, the error of the SEED is about 219.2% at 10 MHz AC characteristics, but the maximum error of the proposed method is only 7.8% Hence, compared with the widely used SEED method, this method is more accurate when characterizing the EOS event during AC operation and switching. Index Terms Electric overstress, electrostatic discharge (ESD) transient simulation, wide frequency.", "author_names": [ "Zhenzhen Chen" ], "corpus_id": 236317100, "doc_id": "236317100", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Physics based Transient Simulation and Modeling Method for Wide frequency Electrical Overstress Including ESD", "venue": "", "year": 2021 }, { "abstract": "A CMOS SCR compact model is developed for circuit simulation of ESD protection circuits. The model is comprised of coupled NPN and PNP transistors. A previously unnoted interaction between these transistors is described, resulting in improved agreement between simulation and measurement. This model addresses fundamental limitations of previous models, allowing for improved simulation accuracy, while limiting the number of parameters. The model parameters are scalable with respect to the layout spacings.", "author_names": [ "Robert Mertens", "Elyse Rosenbaum" ], "corpus_id": 5879972, "doc_id": "5879972", "n_citations": 21, "n_key_citations": 3, "score": 0, "title": "A physics based compact model for SCR devices used in ESD protection circuits", "venue": "2013 IEEE International Reliability Physics Symposium (IRPS)", "year": 2013 }, { "abstract": "This paper reviews electrostatic discharge (ESD) investigations on laterally diffused MOS (LDMOS) and drain extended MOS (DeMOS) devices. The limits of the safe operating area of LDMOS/DeMOS devices and device physics under ESD stress are discussed under various biasing conditions and layout schemes. Specifically, the root cause of early filament formation is highlighted. Differences in filamentary nature among various LDMOS/DeMOS devices are shown. Based on the physical understanding, device optimization guidelines are given. Finally, an outlook on technology scaling is presented.", "author_names": [ "Mayank Shrivastava", "Harald Gossner" ], "corpus_id": 35270203, "doc_id": "35270203", "n_citations": 64, "n_key_citations": 2, "score": 0, "title": "A Review on the ESD Robustness of Drain Extended MOS Devices", "venue": "IEEE Transactions on Device and Materials Reliability", "year": 2012 }, { "abstract": "In order to obtain the damage rule of microwave semiconductor devices caused by electromagnetic pulse and study the electrostatic damage mechanism of the devices,the failure mode of semiconductor devices caused by ESD,such as apparent failure and potential failure,is introduced.The damage modeling is analyzed.Finally,the inherent damage reason of the device under electrostatic discharge stress is obtained by analyzing the physics mechanism of the burned device.Breakdown may happen under the action of ESD EMP,the internal electric field and the current density of the device increase,which cause the temperature rise and result in microwave semiconductor device burned.", "author_names": [ "Tan Zhiliang" ], "corpus_id": 114895728, "doc_id": "114895728", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analysis of failure mechanism of microwave semiconductor devices caused by ESD", "venue": "", "year": 2013 }, { "abstract": "In this paper, we present the detailed physical insights into the electrostatic discharge (ESD) behavior of hydrogenated amorphous silicon (a Si:H) based thin film transistor (TFT) technology. Device failure under ESD conditions is studied in detail using electrical and optical techniques. Device degradation under ESD timescales is studied using real time capacitance voltage and a spatially variant degradation behavior is reported. Variations in material properties are studied before and after device failure using Raman spectroscopy. Device dimension dependent failure mechanism is explored. Impact of stressing conditions and presence of top passivation on failure behavior is also explored. Failure physics of technologically relevant device architectures including diode connected transistors (gated diodes) and drain underlap TFTs and their increased ESD robustness is discussed. Finally, ESD behavior of a Si:H based TFTs is discussed.", "author_names": [ "Rajat Sinha", "Prasenjit Bhattacharya", "Icko Eric Timothy Iben", "Sanjiv Sambandan", "Mayank Shrivastava" ], "corpus_id": 155108420, "doc_id": "155108420", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "ESD Reliability Study of a Si:H Thin Film Transistor Technology: Physical Insights and Technological Implications", "venue": "IEEE Transactions on Electron Devices", "year": 2019 }, { "abstract": "In this paper, for the first time, the record high performance top gated graphene technology platform is used for electrostatic discharge (ESD) physics exploration while investigating the implications of various design and technology options. Impact of diffusive versus ballistic carrier transport on the failure mechanism in top gate as well as back gate graphene FET (GFET) is investigated. A unique contact limited failure in graphene transistors is reported. Physical insights on current saturation in GFET and unique step by step failure in dielectric capped transistors are presented for the first time. Moreover, device degradation under ESD timescales and its implications on current saturation are revealed. Finally, the influence of various top gate designs on the ESD performance is reported. New physical insights and matured GFET technology has eventually enabled record high ESD robustness.", "author_names": [ "Kranthi Karmel Nagothu", "Abhishek Mishra", "Adil Meersha", "Mayank Shrivastava" ], "corpus_id": 56719181, "doc_id": "56719181", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "On the ESD Behavior of Large Area CVD Graphene Transistors: Physical Insights and Technology Implications", "venue": "IEEE Transactions on Electron Devices", "year": 2019 } ]

[ { "abstract": "In the development of next generation power modules for electric vehicles, demands for high efficiency, reliability, low cost, high power density and therefore small size are of major importance. A promising approach is the embedding of power semiconductor devices into a printed circuit board (PCB) as investigated by the HI LEVEL project. This paper deals with the research, design and experimental verification of a current sensor based on the principle of a Rogowski coil, which is integrated into a PCB, so that it can measure the device current of the embedded power semiconductor devices. As switched mode currents are to be measured, the dynamics of the current sensor were of major concern. Moreover, as large voltage gradients caused by the semiconductor devices inject parasitic capacitive currents into the coil, a differential measurement approach was selected for cancelling out disturbances caused by capacitive coupling.", "author_names": [ "J N Fritz", "Christoph Neeb", "Rik W De Doncker" ], "corpus_id": 73682531, "doc_id": "73682531", "n_citations": 10, "n_key_citations": 0, "score": 1, "title": "A PCB Integrated Differential Rogowski Coil for Non Intrusive Current Measurement Featuring High Bandwidth and dv/dt Immunity", "venue": "", "year": 2015 }, { "abstract": "Percentage Differential Protection (PDP) is well known as the main Unit Protection Relay of Power Transformer all over the world. The researchers suggested using a novel Current Transformer (CT) with a new approach for fault detections, to improve the characteristic of this relay. MATLAB Simulink tools software used to model the Rogowski Coil (RC) with the new PDP Relay characteristic. Reducing the min operating level point and expanding the operation region by revoking the second slope in the characteristic of the relay by implementing Extended Park's Vector Approach (EPVA) for faults detection. The paper also sheds light on removing the saturation error curve from the total error in the characteristic of PDP relay using the linear CT characteristics of Rogowski Coil. Consequently, a better sensitivity achieved specially for small differential currents in the secondary system. By this method, good indications of quitting few currents on primary terminal of power transformer were achieved. This performance of algorithm is due to the EPVA's analyzation which depends on spectrum analysis.", "author_names": [ "Ahmed Sherwani", "Ali Kircay" ], "corpus_id": 220939716, "doc_id": "220939716", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Improving the Characteristic of Percentage Differential Relay of Power Transformer using Rogowski Coil with Extended Park's Vector Approach", "venue": "2020 International Congress on Human Computer Interaction, Optimization and Robotic Applications (HORA)", "year": 2020 }, { "abstract": "This paper presents a simple method for improving the security and reliability of Harmonic Blocking Algorithms (HBAs) in differential protection of power transformers. In the proposed method, instead of using conventional Current Transformer (CT) Rogowski Coil Sensor (RCS) is utilized for sensing the transformer currents. Based on a theoretic analysis, it is shown that the use of RCS increases the margin between the second harmonic ratio levels of the energization and fault conditions, thereby increasing the HBAs security. Besides, the use of RCS has the additional advantage of eliminating the problem of CT saturation, which might cause malfunction of the differential relay. The validity of the proposed technique is demonstrated by evaluating extensive test cases in different operating conditions, which are recorded by digital simulations in PSCAD/EMTDC software. Overall, the results demonstrate that the proposed approach improves the security of HBAs by about 6.8%", "author_names": [ "Sepehr Karimi", "Farshid Naseri", "Ramin Qaedi", "Ebrahim Farjah", "Teymoor Ghanbari" ], "corpus_id": 227232656, "doc_id": "227232656", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Application of Rogowski Coil for Improving Security of Transformer Differential Protection", "venue": "2020 28th Iranian Conference on Electrical Engineering (ICEE)", "year": 2020 }, { "abstract": "In this paper, a developed method for measuring power frequency ac current using Rogowski coil is presented. The proposed method uses a differentiator in order to reconstruct the current that is intended to be measured. This method gives accurate results as well as it requires only few samples to successfully reconstruct the power frequency current. These advantages are investigated by experimental testing using two different designs of Rogowski coil. The first Rogowski coil has a higher number of turns as compared with the second one. In addition, a digital signal processor is integrated with the coil to implement the proposed reconstruction method. The obtained results give an evidence for the proposed method validity as well as its efficacy.", "author_names": [ "Mohamed E Ibrahim", "Amr M Abd-Elhady" ], "corpus_id": 37417492, "doc_id": "37417492", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Differential Reconstruction Method for Power Frequency AC Current Measurement Using Rogowski Coil", "venue": "IEEE Sensors Journal", "year": 2016 }, { "abstract": "Busbar protection grids are always important, but high speed regimes are now needed more than ever because many power systems operating in microgrid should achieve safe and stabile operation. For this purpose, protection concepts that require time coordination such as overcurrent relays and distance protection are no longer acceptable. Digital differential protection uses innovative algorithms to comply with the protection requirements busbar with fast times switching for all faults. The proposed scheme provides protection for any fault in the Busbar of the microgrid and isolates the smallest part possible, to allow the rest of the system to continue operating. The main difficulty in busbar protection using current transformer (CT) may appear during saturation. Therefore, with the use of the Rogowski coil current sensors (RC) can overcome the saturation in CT; in addition, it has many unique features. The protection system consists of a unique combination using differential protection using RC and an intelligent tool to achieve reliable busbar protection with a minimum of delay for evolving faults. Performance has been verified for a variety of operating conditions. The results have confirmed the superior performance of the protection solution. In general, Rogowski coils have performance characteristics that are favorable compared to conventional CTs.", "author_names": [ "Ali Hadi Abdulwahid", "Shaorong Wang" ], "corpus_id": 19350807, "doc_id": "19350807", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "A busbar differential protection based on fuzzy reasoning system and Rogowski coil current sensor for microgrid", "venue": "2016 IEEE PES Asia Pacific Power and Energy Engineering Conference (APPEEC)", "year": 2016 }, { "abstract": "The Rogowski coil current sensor consists of a Rogowski coil and an integrator. The coil output voltage is proportional to the derivative of the primary current, and the integrator converts the differential into a normal state. Its advantages of good linearity and light weight are gaining more and more attention in the current sampling of smart grids and new electrical equipment, but Rogowski coils have different requirements in different application scenarios. In order to meet the practical needs of current measurement of parallel superconducting units in high temperature superconducting devices, a Rogowski coil can be designed and fabricated from use for cryogenic environments. The Rogowski coil bobbin is made of Fiber Reinforced Plastic (FRP) which has a small deformation in a cryogenic environment and can ensure the accuracy of current measurement. The experimental results show that the linearity of the Rogowski coil is well, and the linear scale factor of the normal temperature environment and the cryogenic environment is well, which can be used to measure the current of the superconducting parallel unit.", "author_names": [ "Shaoqun Cao", "Jingye Zhang", "Wenhan Zha", "Chuang Zhao", "Benkang Yang", "Maxiang Zhu" ], "corpus_id": 216586805, "doc_id": "216586805", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Experimental Study on Current Measurement of Rogowski Coil in a Cryogenic Environment", "venue": "2019 IEEE 3rd International Electrical and Energy Conference (CIEEC)", "year": 2019 }, { "abstract": "The invention discloses a PCB Rogowski coil current inductor based on differential wiring. The PCB Rogowski coil current inductor comprises a PCB (Printed Circuit Board) which is provided with a through hole, inner diameter guide hole pairs and out diameter guide hole pairs, wherein the inner diameter guide hole pairs and out diameter guide hole pairs are distributed around the center of a PCB coil and respectively include a pair of guide holes which are spaced with a preset distance and have equal distance from the center; the PCB is also provided with a common terminal via hole and a pair of differential wiring copper foils, wherein the common terminal via hole is positioned on the symmetrical line of one out diameter guide hole pair, the outer diameter guide holes of the out diameter guide hole pair respectively serve as the start point of a first differential copper foil wire and the end point of a second differential copper foil wire, the common terminal via hole serves as the start point and the end point of the first differential copper foil wire, and the first differential copper foil wire and the second differential copper foil wire sequentially pass through the inner diameter guide hole pairs and the outer diameter guide hole pairs to from two parallel coils. Since the differential wiring is adopted, the PCB Rogowski coil current inductor has strictly symmetrical signals and good antijamming capability.", "author_names": [ "" ], "corpus_id": 116321682, "doc_id": "116321682", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "PCB Rogowski coil current inductor based on differential wiring", "venue": "", "year": 2014 }, { "abstract": "High frequency power electronic converters having switching frequency higher than 1MHz require wideband, isolated and loss less current measurement for effective controls, diagnostics and prognostics. In this work, we propose a wideband and contactless current sensing method for isolated and loss less current measurement in high frequency power electronic converters. The proposed method combines two different sensing technologies a Magnetoresistor sensor and a differential Rogowski coil sensor, which have complementary characteristics to achieve a wide sensing bandwidth. We demonstrate through hardware prototypes and experiments that the proposed hybrid sensor yields to a very high sensing bandwidth of DC to 10MHz. The performance of the hybrid sensor is also evaluated in a 1MHz buck converter.", "author_names": [ "Shahriar Jalal Nibir", "Sven Hauer", "Mehrdad Biglarbegian", "Babak Parkhideh" ], "corpus_id": 5029004, "doc_id": "5029004", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Wideband contactless current sensing using hybrid magnetoresistor Rogowski sensor in high frequency power electronic converters", "venue": "2018 IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2018 }, { "abstract": "Implementation of differential protection for transformers of electrical arc furnaces has some challenges because of the secondary high currents (about 100 kA) Conventional Current Transformers (CTs) cannot measure such high currents. Recently, differential protection has been implemented in these transformers using a special type of Rogowski Coil (RC) This report deals with a project of such implementation in Mobarakeh steel company, Isfahan, Iran. As the first report, design outputs of the project are presented.", "author_names": [ "Teymoor Ghanbari", "Haidar Samet", "Mohammad Amin Jarrahi", "Darioush Daryabar" ], "corpus_id": 53018585, "doc_id": "53018585", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Implementation of Rogowski Coil Based Differential Protection on Electric Arc Furnace Transformers of Mobarakeh Steel Company: Design Step", "venue": "2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC I&CPS Europe)", "year": 2018 }, { "abstract": "Ben Fa Ming Gong Kai Liao Yi Chong Ji Yu Chai Fen Bu Xian De PCBLuo Shi Xian Quan Dian Liu Gan Ying Qi ,Bao Gua PCBBan ,PCBBan Shang Kai She You Tong Kong Nei Jing Dao Kong Dui He Wai Jing Dao Kong Dui ,Nei Jing Dao Kong Dui He Wai Jing Dao Kong Dui Yan PCBXian Quan De Yuan Xin Fen Bu ;Wai Jing Dao Kong Dui He Nei Jing Dao Kong Dui Jun Bao Gua Yi Dui Jian Ge Yu Ding Ju Chi Qie Ju Chi Yuan Xin Xiang Deng De Dao Kong ,PCBBan Shang Huan She Zhi You Yi Ge Gong Gong Duan Guo Kong He Yi Dui Chai Fen Bu Xian Tong Bo ,Gong Gong Duan Guo Kong Wei Yu Mou Yi Wai Jing Dao Kong Dui De Dui Cheng Xian Shang ,Gai Wai Jing Dao Kong Dui De Wai Jing Dao Kong Fen Bie Wei Di Yi Chai Fen Tong Bo Xian De Qi Dian Di Er Chai Fen Tong Bo Xian De Zhong Dian ;Gong Gong Duan Guo Kong Wei Di Yi Chai Fen Tong Bo Xian De Qi Dian Ji Di Yi Chai Fen Tong Bo Xian De Zhong Dian ;Di Yi Chai Fen Tong Bo Xian He Di Er Chai Fen Tong Bo Xian Yi Ci Chuan Guo Nei Jing Dao Kong Dui He Wai Jing Dao Dui Xing Cheng Liang Ge Ping Xing De Xian Quan Ben Fa Ming You Yu Cai Yong Liao Chai Fen Bu Xian ,Chai Fen Xin Hao Yan Ge Dui Cheng ,You Hen Hao De Kang Gan Rao Neng Li", "author_names": [ "" ], "corpus_id": 115642560, "doc_id": "115642560", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Based on the differential wirings pcb Rogowski coil current sensors", "venue": "", "year": 2014 } ]

[ { "abstract": "Large scale graphene electronics requires lithographic patterning of narrow graphene nanoribbons for device integration. However, conventional lithography can only reliably pattern approximately 20 nm wide GNR arrays limited by lithography resolution, while sub 5 nm GNRs are desirable for high on/off ratio field effect transistors at room temperature. Here, we devised a gas phase chemical approach to etch graphene from the edges without damaging its basal plane. The reaction involved high temperature oxidation of graphene in a slightly reducing environment in the presence of ammonia to afford controlled etch rate (less than or approximately 1 nm min( 1) We fabricated approximately 20 30 nm wide graphene nanoribbon arrays lithographically, and used the gas phase etching chemistry to narrow the ribbons down to <10 nm. For the first time, a high on/off ratio up to approximately 10(4) was achieved at room temperature for field effect transistors built with sub 5 nm wide graphene nanoribbon semiconductors derived from lithographic patterning and narrowing. Our controlled etching method opens up a chemical way to control the size of various graphene nano structures beyond the capability of top down lithography.", "author_names": [ "Xinran Wang", "H Dai" ], "corpus_id": 205300287, "doc_id": "205300287", "n_citations": 363, "n_key_citations": 5, "score": 1, "title": "Etching and narrowing of graphene from the edges.", "venue": "Nature chemistry", "year": 2010 }, { "abstract": "Opening the transport gap in graphene by minimizing its width is highly desirable to achieve outstanding switching performance, i.e. the high on/off ratio, in its field effect transistors (FETs) In this letter, we propose a simple method to open a comparable transport gap in graphene by narrowing down it into graphene nanoribbon (GNR) via the conventional nanofabrication procedure. In the process, GNR capped with a 50 nm wide hydrogen silsesquioxane mask is trimmed down from the edges by lateral plasma etching. The on/off ratio of the FET device is dramatically enhanced by two orders of magnitude as etching duration increases. The large on/off ratios of ~47 and ~105 are achieved at room temperature and 5.4 K, respectively. The electrical measurement reveals a transport gap opening of ~145 meV in GNR, which corresponds to a resulting width of <10 nm.", "author_names": [ "Jian Sun", "Takuya Iwasaki", "Manoharan Muruganathan", "Hiroshi Mizuta" ], "corpus_id": 119838771, "doc_id": "119838771", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Lateral plasma etching enhanced on/off ratio in graphene nanoribbon field effect transistor", "venue": "", "year": 2015 }, { "abstract": "We devised a controlled hydrogen plasma reaction at 300 degC to etch graphene and graphene nanoribbons (GNRs) selectively at the edges over the basal plane. Atomic force microscope imaging showed that the etching rates for single layer and few layer =2 layers) graphene are 0.27 0.05 nm/min and 0.10 0.03 nm/min, respectively. Meanwhile, Raman spectroscopic mapping revealed no D band in the planes of single layer or few layer graphene after the plasma reaction, suggesting selective etching at the graphene edges without introducing defects in the basal plane. We found that hydrogen plasma at lower temperature (room temperature) or a higher temperature (500 degC) could hydrogenate the basal plane or introduce defects in the basal plane. Using the hydrogen plasma reaction at the intermediate temperature (300 degC) we obtained narrow, presumably hydrogen terminated GNRs (sub 5 nm) by etching of wide GNRs derived from unzipping of multiwalled carbon nanotubes. Such GNRs exhibited semiconducting characteristics with high on/off ratios ~1000) in GNR field effect transistor devices at room temperature.", "author_names": [ "Liming Xie", "Liying Jiao", "H Dai" ], "corpus_id": 1132213, "doc_id": "1132213", "n_citations": 186, "n_key_citations": 3, "score": 0, "title": "Selective etching of graphene edges by hydrogen plasma.", "venue": "Journal of the American Chemical Society", "year": 2010 }, { "abstract": "We report a facile one step in situ synthesis of amino functionalized graphene dots. These quantum dots were employed for the detection of glucose in both standard aqueous solutions and commercially available fruit juice to assess its practicability. The characterization of the quantum dots revealed that they were decorated with amine functionality. Additionally, the interaction between glucose and amine functionalized graphene quantum dots gave enhancement in the UV vis absorption and photoluminescence (PL) due to aggregation of quantum dots via glucose link. Therefore, the quantum dots were able to detect the concentration of glucose in solution exhibiting linearity from 0.1 to 10 mM and 50 500 mM with a sensitivity transition from 10 mM to 50 mM. The limit of detection for the determination of glucose was found to be 10 mM. This determination was agreed from both UV Vis absorption and PL spectroscopy. However, the PL emission method of determination was most suited with its very high accuracy of 98.04 1.96% and 97.33 2.67% for the linear range of glucose concentration within 0.1 10 mM and 50 500 mM, respectively. The PL enhancement was highly selective towards glucose in mixture of other form of sugars making it suitable for determining glucose in food samples.", "author_names": [ "Praveen Mishra", "Badekai Ramachandra Bhat" ], "corpus_id": 195830777, "doc_id": "195830777", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Aggregative ways of graphene quantum dots with nitrogen rich edges for direct emission spectrophotometric estimation of glucose.", "venue": "Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy", "year": 2019 }, { "abstract": "We investigate the etching of a pure hydrogen plasma on graphite samples and graphene flakes on SiO2 and hexagonal boron nitride substrates. The pressure and distance dependence of the graphite exposure experiments reveals the existence of two distinct plasma regimes: the direct and the remote plasma regime. Graphite surfaces exposed directly to the hydrogen plasma exhibit numerous etch pits of various size and depth, indicating continuous defect creation throughout the etching process. In contrast, anisotropic etching forming regular and symmetric hexagons starting only from preexisting defects and edges is seen in the remote plasma regime, where the sample is located downstream, outside of the glowing plasma. This regime is possible in a narrow window of parameters where essentially all ions have already recombined, yet a flux of H radicals performing anisotropic etching is still present. At the required process pressures, the radicals can recombine only on surfaces, not in the gas itself. Thus, the tube material needs to exhibit a sufficiently low H radical recombination coefficient, such as found for quartz or pyrex. In the remote regime, we investigate the etching of single layer and bilayer graphene on SiO2 and hexagonal boron nitride substrates. We find isotropic etching for single layer graphene on SiO2, whereas we observe highly anisotropic etching for graphene on a hexagonal boron nitride substrate. For bilayer graphene, anisotropic etching is observed on both substrates. Finally, we demonstrate the use of artificial defects to create well defined graphene nanostructures with clean crystallographic edges.Nanofabrication: remote etching of graphene on hBN is highly anisotropicEtching of graphite with hydrogen plasma gives rise to two distinct etching regimes, governed by the degree of direct plasma exposure. A team led by D. M. Zumbuhl at the University of Basel investigated the interplay between graphite exposure to pure hydrogen plasma and the resulting etching features. When the sample surface is in direct contact with the plasma, a defect rich etching regime occurs, resulting in the formation of etch pits with variable size. However, when graphite is away from the plasma source, a remote anisotropic etching takes place, giving rise to regular hexagons originating from localized defects and edges. In the latter regime, the authors found that in the case of graphene, isotropic etching is obtained using SiO2 as substrate, whereas highly anisotropic etching occurs when graphene is placed on hBN.", "author_names": [ "Dorothee Hug", "Simon Zihlmann", "Mirko K Rehmann", "Yemliha Bilal Kalyoncu", "Timothy N Camenzind", "Laurent Marot", "K Watanabe", "Takashi Taniguchi", "Dominik M Zumbuhl" ], "corpus_id": 115141171, "doc_id": "115141171", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Anisotropic etching of graphite and graphene in a remote hydrogen plasma", "venue": "npj 2D Materials and Applications", "year": 2017 }, { "abstract": "To replace the noble metal Pt catalysts for oxygen reduction reaction (ORR) developing efficient and earth abundant electrocatalysts is of great importance. Both the morphology and composition engineering of graphene could effectively modify the electronic structure to optimize its electrocatalytic performance for ORR. Here, we report an effective method to dope carbon materials with N, by which the N doping concentration and form could be well controlled. We first grow 3D graphene fibers (3DGFs) by thermal chemical vapor deposition, which are then treated with acid or heated in air and heated in NH3 in succession, obtaining N,O codoped 3DGFs. The codoped 3DGFs exhibit outstanding electrocatalytic performance toward ORR with onset potential of 1.01 V, half wave potential of 0.883 V, long term operation stability with 90% current retention after 50 h, and a good methanol tolerance in alkaline solutions, which are superior to 20 wt% Pt/C catalyst and other reported advanced metal free catalysts. The excellent catalytic performance of the 3DGFs probably arises from the synergic effect of the morphology and composition engineering, e.g. the edges and doping, especially the pyridine N. The present work is expected to open up new approach to design outstanding metal free carbon based electrocatalysts for ORR.", "author_names": [ "Jie Zeng", "Yongbiao Mu", "Xixi Ji", "Ziji Lin", "Yanhong Lin", "Yihui Ma", "Zhongxing Zhang", "Shuguang Wang", "Zhonghua Ren", "Jie Yu" ], "corpus_id": 201661306, "doc_id": "201661306", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "N,O codoped 3D graphene fibers with densely arranged sharp edges as highly efficient electrocatalyst for oxygen reduction reaction", "venue": "Journal of Materials Science", "year": 2019 }, { "abstract": "Graphene growth and etching are reciprocal processes that can reach a dynamic balance during chemical vapor deposition (CVD) Most commonly, the growth of graphene is the dominate process, while the etching of graphene is a recessive process often neglected during CVD growth of graphene. We show here that through the rational design of low pressure CVD of graphene in hydrogen diluted methane and regulation of the flow rate of H2, the etching effect during the growth process of graphene could be prominent and even shows macroscopic selectivity. On this basis, etching controlled growth and synthesis of graphene with various morphologies from compact to dendritic even to fragmentary have been demonstrated. The morphology selection mechanism is clarified through phase field theory based on simulations. This study not only presents an intriguing case for the fundamental mechanism of CVD growth but also provides a facile method for the synthesis of high quality graphene with trimmed morphologies.", "author_names": [ "Birong Luo", "Enlai Gao", "Dechao Geng", "Huaping Wang", "Zhi Ping Xu", "Gui Yu" ], "corpus_id": 99992086, "doc_id": "99992086", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Etching Controlled Growth of Graphene by Chemical Vapor Deposition", "venue": "", "year": 2017 }, { "abstract": "Graphene liquid cell electron microscopy provides the ability to observe nanoscale chemical transformations and dynamics as the reactions are occurring in liquid environments. This manuscript describes the process for making graphene liquid cells through the example of graphene liquid cell transmission electron microscopy (TEM) experiments of gold nanocrystal etching. The protocol for making graphene liquid cells involves coating gold, holey carbon TEM grids with chemical vapor deposition graphene and then using those graphene coated grids to encapsulate liquid between two graphene surfaces. These pockets of liquid, with the nanomaterial of interest, are imaged in the electron microscope to see the dynamics of the nanoscale process, in this case the oxidative etching of gold nanorods. By controlling the electron beam dose rate, which modulates the etching species in the liquid cell, the underlying mechanisms of how atoms are removed from nanocrystals to form different facets and shapes can be better understood. Graphene liquid cell TEM has the advantages of high spatial resolution, compatibility with traditional TEM holders, and low start up costs for research groups. Current limitations include delicate sample preparation, lack of flow capability, and reliance on electron beam generated radiolysis products to induce reactions. With further development and control, graphene liquid cell may become a ubiquitous technique in nanomaterials and biology, and is already being used to study mechanisms governing growth, etching, and self assembly processes of nanomaterials in liquid on the single particle level.", "author_names": [ "Matthew R Hauwiller", "Justin C Ondry", "A Paul Alivisatos" ], "corpus_id": 44083534, "doc_id": "44083534", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Using Graphene Liquid Cell Transmission Electron Microscopy to Study in Situ Nanocrystal Etching", "venue": "Journal of visualized experiments JoVE", "year": 2018 }, { "abstract": "Graphene is a novel two dimensional nanomaterial that holds great potential in electronic and sensor applications. By etching the edges to form nanoribbons or introducing defects on the basal plane, it has been demonstrated that the physical and chemical properties of graphene can be drastically altered. However, the lithographic or chemical techniques required to reliably produce such nanoribbons remain challenging. Here, we report the fabrication of nanosensors based on holey reduced graphene oxide (hRGO) which can be visualized as interconnected graphene nanoribbons. In our method, enzymatic oxidation generated holes within the basal plane of graphene oxide, and after reduction with hydrazine, hRGO was formed. When decorated with Pt nanoparticles, hRGO exhibited a large and selective electronic response toward hydrogen gas. By combining experimental results and theoretical modeling, we propose that the increased edge to plane ratio, oxygen moieties, and Pt nanoparticle decoration were responsible for the observed gas sensing with hRGO nanostructures.", "author_names": [ "Harindra Vedala", "Dan C Sorescu", "Gregg P Kotchey", "Alexander Star" ], "corpus_id": 528751, "doc_id": "528751", "n_citations": 158, "n_key_citations": 1, "score": 0, "title": "Chemical sensitivity of graphene edges decorated with metal nanoparticles.", "venue": "Nano letters", "year": 2011 }, { "abstract": "Graphene is a two dimensional crystal that is stripped from pristine graphite and made of single layer of carbon atoms. Containing numerous functional groups, graphene derivatives (GDs) could be easily modified and have aroused great attention for potential applications in biomedicine. However, pristine graphene and graphene oxide (GO) could arouse cell and animal toxicity. To screen GDs with high biocompatibility applied for biomedicine, general comparison was performed about the toxicities of six GDs with diverse types of surface modification, size, and redox state, including GO, reduced GO (rGO) graphene quantum dot (GQD) aminated GQD (GQD NH2) carboxyl GQD (GQD COOH) and graphene oxide quantum dot (GOQD) In contrast, it was found that large particle size, oxidation state, high concentration, and long exposure time were unfavorable factors affecting the cell viability. We further explored the mechanism of different toxicity, which could be contribute to cell membrane destruction by sharpened edges of GDs (LDH release, hemolysis) ROS production, immuno inflammatory responses, and activation of apoptotic pathways (IKK/IkBa/NF kB and BAX/BCL 2) Overall, our combined data primarily explored the related biochemical and molecular mechanism underlying the biological behaviors and toxicity of GDs, and we also identified GQD, GQD NH2, GQD COOH, and GOQD could be safely used for biomedical application as drug carriers.", "author_names": [ "Jian Li", "Xizhi Zhang", "Jing Jiang", "Yanjie Wang", "Haiye Jiang", "Junhua Zhang", "Xinmin Nie", "Bin Liu" ], "corpus_id": 52306417, "doc_id": "52306417", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Systematic Assessment of the Toxicity and Potential Mechanism of Graphene Derivatives In Vitro and In Vivo", "venue": "Toxicological sciences an official journal of the Society of Toxicology", "year": 2019 } ]

[ { "abstract": "Recently, the semiconductor counterfeiting has become a serious problem. To counter this problem, Physical Unclonable Function (PUF) has been attracted attention. However, the risk of machine learning attacks for PUF is pointed out. To verify the safety of PUF, the evaluation (tamper resistance) against machine learning attacks in the difference of PUF implementations is very important. However, the tamper resistance evaluation in the difference of PUF implementation has barely been reported. Therefore, this study evaluates the tamper resistance of PUF in the difference of field programmable gate array (FPGA) implementations against machine learning attacks. Experiments using an FPGA clarified the arbiter PUF of the lookup table implementation has the tamper resistance against machine learning attacks.", "author_names": [ "Yusuke Nozaki", "Masaya Yoshikawa" ], "corpus_id": 35854971, "doc_id": "35854971", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Tamper resistance evaluation of PUF implementation against machine learning attack", "venue": "ICBEA '17", "year": 2017 }, { "abstract": "With growing process complexity and the increasing number of process steps, early prediction of device performance has become an important task in semiconductor manufacturing process control. Machine learning (ML) techniques allow us to link in line measurements to End Of Line (EOL) electrical tests. In our paper, we use reflectance spectra obtained from the scatterometry tool to predict both metal line resistance and capacitance. We used IMEC N14 process flow with LELE double patterning at the M1 stage. Special designs of experiments (DOE) for multiple parameters allowed us to create a metrology solution for the entire process window and test its accuracy for all POI. Induced variations of both line CDs and space CDs, together with specially designed measurement sites, created wide variations both in metal line resistance and capacitance. Reflectance spectra were collected in line at two process steps defining metal lines: HM etch and Cu CMP at multiple targets, including E test measurement sites, together with reference metrology for overlay (OV) and CD (by using Diffraction Based Overlay (DBO) and CD SEM) EOL electrical test results were used for the ML training procedure for early prediction of patterning effects (both CD and OL) on electrical performance enabling early decisions and cost reduction by discarding out of spec wafers before they reached the electrical test. It was shown that ML OCD predictive techniques are complimentary to the OCD model based solutions for geometrical parameters widely used for in line APC.", "author_names": [ "Sayantan Das", "Joey Hung", "Sandip Halder", "Guillaume Schelcher", "Roy Koret", "Igor Turovets", "Mohamed Saib", "A L Charley", "Matthew Sendelbach", "Avron Ger", "P Leray" ], "corpus_id": 108324774, "doc_id": "108324774", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Machine learning for predictive electrical performance using OCD", "venue": "Advanced Lithography", "year": 2019 }, { "abstract": "The physical unclonable functions (PUFs) have been attracted attention to prevent semiconductor counterfeits. However, the risk of machine learning attack for an arbiter PUF, which is one of the typical PUFs, has been reported. Therefore, an XOR arbiter PUF, which has a resistance against the machine learning attack, was proposed. However, in recent years, a new machine learning attack using power consumption during the operation of the PUF circuit was reported. Also, it is important that the detailed tamper resistance verification of the PUFs to consider the security of the PUFs in the future. Therefore, this study proposes a new machine learning attack using electromagnetic waveforms for the XOR arbiter PUF. Experiments by an actual device evaluate the validity of the proposed method and the security of the XOR arbiter PUF.", "author_names": [ "Yusuke Nozaki", "Masaya Yoshikawa" ], "corpus_id": 5048647, "doc_id": "5048647", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "EM based machine learning attack for XOR arbiter PUF", "venue": "ICMLSC '18", "year": 2018 }, { "abstract": "Interest in resistance switching is currently growing apace. The promise of novel high density, low power, high speed nonvolatile memory devices is appealing enough, but beyond that there are exciting future possibilities for applications in hardware acceleration for machine learning and artificial intelligence, and for neuromorphic computing. A very wide range of material systems exhibit resistance switching, a number of which primarily transition metal oxides are currently being investigated as complementary metal oxide semiconductor (CMOS) compatible technologies. Here, the case is made for silicon oxide, perhaps the most CMOS compatible dielectric, yet one that has had comparatively little attention as a resistance switching material. Herein, a taxonomy of switching mechanisms in silicon oxide is presented, and the current state of the art in modeling, understanding fundamental switching mechanisms, and exciting device applications is summarized. In conclusion, silicon oxide is an excellent choice for resistance switching technologies, offering a number of compelling advantages over competing material systems.", "author_names": [ "Adnan Mehonic", "Alexander L Shluger", "David Z Gao", "Ilia Valov", "Enrique A Miranda", "Daniele Ielmini", "Alessandro Bricalli", "Elia Ambrosi", "Can Li", "J Joshua Yang", "Qiangfei Xia", "Anthony J Kenyon" ], "corpus_id": 205286992, "doc_id": "205286992", "n_citations": 83, "n_key_citations": 3, "score": 0, "title": "Silicon Oxide (SiOx A Promising Material for Resistance Switching?", "venue": "Advanced materials", "year": 2018 }, { "abstract": "Power chips such as Metal Oxide Field Effect Transistors (MOSFETs) are widely used and can be found in many electronics and electrical products. The ability to predict the degradation of such power electronic devices can minimise the risk of their failure during operation and support maintenance planning operations. In this study, a data driven prognostics approach using system identification and machine learning modelling technique is developed and used to predict the time to failure of MOSFET TO 220 packages associated with delamination failure mode of the die attachment. Run to failure data under thermal overstress loading conditions for power chip devices, available from the NASA Prognostics Centre data repository, is used to develop a data driven prognostic model that can be used to predict the time to failure (TtF) of power MOSFETs under accelerated test loads. An increment in ON state resistance of the MOSFET is used as precursor for device failure through die attach degradation. Results from this research show that when monitored data from a damage indicator for a particular failure mode of an electronic package changes dynamically, data driven modelling using engineering control techniques such as State Space representation is capable of producing reliable, multi step ahead predictions for the time to failure of the device.", "author_names": [ "Mominul Ahsan", "Stoyan Stoyanov", "Chris Bailey" ], "corpus_id": 52129477, "doc_id": "52129477", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Data Driven Prognostics for Failure of Power Semiconductor Packages", "venue": "2018 41st International Spring Seminar on Electronics Technology (ISSE)", "year": 2018 }, { "abstract": "Recently, semiconductor counterfeiting has become serious problems due to the advancement of reverse engineering technologies. The physical unclonable function (PUF) is now attracting attention as a technique to prevent counterfeiting. The PUF utilizes each device's analog characteristics, which are generated by variations on LSI manufacturing, as a measure for individual identification. However, the vulnerability of PUF to machine learning attacks has been pointed out. Therefore, it is important to examine the vulnerability of PUF from a view point of hardware security. This paper discusses the vulnerability of the proposed 4 MUXs PUF for attack using support vector machine (SVM) Experiments show superior resistance for SVM attacks in comparison with conventional PUF.", "author_names": [ "S Kiryu", "Kensaku Asahi", "Masaya Yoshikawa" ], "corpus_id": 52004075, "doc_id": "52004075", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Vulnerability evaluation of multiplexing PUF for SVM attacks", "venue": "ICSEng", "year": 2014 }, { "abstract": "As the micro electro mechanical machine (MEMS) industry is maturing, an increased array of product applications and devices are being introduced. As these devices are being developed new processes are required to control and attain the desired levels of polysilicon stress. In this work the relationship between polysilicon blanket residual stress and dopant concentration and anneal conditions are investigated. It was found that as the sheet resistance increased, the magnitude of the stress increased several orders of magnitude. Annealing the wafers for increased durations and multiple cycles lowered the level of stress observed while reducing the response to dopant concentration. The response was reduced by fifty percent for a time increase from 20 to 180 minutes. It is suggested that specific levels of stress are best attained with modifications to the dopant concentration for the required thermal cycles. The characterization performed allows for reduced learning cycles and cost in the development of new MEMS process flows to achieve first pass success for device specific requirements.", "author_names": [ "Jerzy Woloszyn" ], "corpus_id": 29987722, "doc_id": "29987722", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "A method for controlling residual film stress in LPCVD polysilicon films for surface micromachined MEMS", "venue": "2004 IEEE/SEMI Advanced Semiconductor Manufacturing Conference and Workshop (IEEE Cat. No.04CH37530)", "year": 2004 }, { "abstract": "While spin qubits based on gate defined quantum dots have demonstrated very favorable properties for quantum computing, one remaining hurdle is the need to tune each of them into a good operating regime by adjusting the voltages applied to electrostatic gates. The automation of these tuning procedures is a necessary requirement for the operation of a quantum processor based on gate defined quantum dots, which is yet to be fully addressed. We present an algorithm for the automated fine tuning of quantum dots, and demonstrate its performance on a semiconductor singlet triplet qubit in GaAs. The algorithm employs a Kalman filter based on Bayesian statistics to estimate the gradients of the target parameters as function of gate voltages, thus learning the system response. The algorithm's design is focused on the reduction of the number of required measurements. We experimentally demonstrate the ability to change the operation regime of the qubit within 3 to 5 iterations, corresponding to 10 to 15 minutes of lab time.", "author_names": [ "Julian D Teske", "Simon Sebastian Humpohl", "Ren'e Otten", "Patrick Bethke", "Pascal Cerfontaine", "Jonas Dedden", "Arne Ludwig", "Andreas Dirk Wieck", "Hendrik Bluhm" ], "corpus_id": 117683624, "doc_id": "117683624", "n_citations": 28, "n_key_citations": 1, "score": 0, "title": "A machine learning approach for automated fine tuning of semiconductor spin qubits", "venue": "Applied Physics Letters", "year": 2019 }, { "abstract": "Semiconductor manufacturers aim to fabricate defect free wafers in order to improve product quality, increase yields, and reduce costs. Typically, wafer defects form spatial patterns that provide useful information, helping to identify problems and faults during the fabrication process. Machine learning (ML) methods have been used to classify these defects in order to locate the root causes of failure. This paper proposes a novel deep structured ML approach as an extension of our previous randomized general regression network (RGRN) model, to identify and classify both single defect and mixed defect patterns. The principal motivation for this paper is that a shallow structured RGRN performs well on single pattern defects, achieving an accuracy of 99.8% but performs poorly when a wafer has mixed defect patterns. The proposed approach improves RGRN performance, particularly on mixed pattern defects, by incorporating a novel information gain (IG) based splitter as well as deep structured ML. A spatial filter is applied to remove random noise and reduce model bias during training. During the first detection stage, the splitter generates unique rules that are built using the IG theory and splits the defects data into single defect and mixed defect patterns. Single defect patterns are then classified by RGRN, whereas mixed defect patterns are fed into the deep structured ML model for further classification. This combination improves the ability of the proposed approach to classify diverse defect patterns and achieve a better overall performance. Our experimental results demonstrate that the proposed approach achieves an overall detection accuracy of 86.17% on a dataset that contains real data representing both single defect and mixed defect patterns, as commonly found in real manufacturing scenarios, outperforming existing ML based models.", "author_names": [ "Ghalia Tello", "Omar Y Al-Jarrah", "Paul Yoo", "Yousof Al-Hammadi", "Sami Hakam Muhaidat", "Uihyoung Lee" ], "corpus_id": 23814032, "doc_id": "23814032", "n_citations": 49, "n_key_citations": 0, "score": 0, "title": "Deep Structured Machine Learning Model for the Recognition of Mixed Defect Patterns in Semiconductor Fabrication Processes", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2018 }, { "abstract": "Semiconductor cluster equipment adds an integral component to the modern semiconductor manufacturing process. These complex tools provide a flexible deployment option to group multiple processing steps into a single piece of equipment, allowing for more efficient processing. They also contribute to a reduction in the number of times a wafer must go through the atmospheric vacuum atmospheric cycle. Such highly automated tools present a complex scheduling challenge where process specific requirements are balanced against a need to achieve maximum wafer throughput in a fault tolerant manner. Software engineers typically build schedulers using a set of manually configured heuristics but this can be a labor intensive process where small changes to the cluster configuration or process requirements can require large changes to the scheduler. Our motivation for this work was to investigate whether a machine learning approach to complex cluster scheduling could be developed more efficiently and at a lower cost than existing methods.", "author_names": [ "Doug Suerich", "Terry Young" ], "corpus_id": 199509662, "doc_id": "199509662", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Machine Learning for Optimized Scheduling in Complex Semiconductor Equipment", "venue": "2019 30th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2019 } ]

[ { "abstract": "Photonic integration technologies have spread in the past decade by means of foundry models that mirror the electronic integrated circuit industry developments of the past century. Several monolithic technologies exist, based on silicon and III V semiconductors. In this paper, we discuss the current state and forthcoming developments of open access photonic foundries whose technology platforms are based on silicon nitride material. The paper presents various silicon nitride technologies and foundries, alongside with access models supported by generic integration and process design kits. Technical features, enabled by different micro fabrication processes and tools are summarized. Application examples and developments of forthcoming incorporation into these platforms are outlined.", "author_names": [ "Pascual Munoz", "Paulus W L van Dijk", "Douwe H Geuzebroek", "Michael Geiselmann", "Carlos Dominguez", "Andim Stassen", "Jose David Domenech", "Michael Zervas", "Arne Leinse", "Chris G H Roeloffzen", "Bernardo Gargallo", "Rocio Banos", "Juan Fernandez", "Gloria Mico Cabanes", "Luis A Bru", "Daniel Pastor" ], "corpus_id": 122399299, "doc_id": "122399299", "n_citations": 24, "n_key_citations": 0, "score": 1, "title": "Foundry Developments Toward Silicon Nitride Photonics From Visible to the Mid Infrared", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2019 }, { "abstract": "Silicon nitride has received a lot of attention during the last ten years, for applications such as bio photonics, tele/datacom, optical signal processing and sensing. In this paper, firstly an updated review of the state of the art of silicon nitride photonics integration platforms will be provided. Secondly, our developments on a moderate confinement Si3N4 platform in the near infrared will be presented. Finally, our steps towards establishing a Si3N4 based platform for broadband operation spanning from visible to mid infrared wavelengths will be introduced.", "author_names": [ "Gloria Mico", "Luis A Bru", "Daniel Pastor", "David Domenech", "Juan Fernandez", "Ana M Sanchez", "Josep M Cirera", "Carlos Dominguez", "Pascual Munoz" ], "corpus_id": 139947321, "doc_id": "139947321", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "Silicon nitride photonics: from visible to mid infrared wavelengths", "venue": "OPTO", "year": 2018 }, { "abstract": "In this paper, a review of the current state of the art of Silicon Nitride photonics integration platforms is presented. These platforms are nowadays employed primarily for bio photonics and telecom applications, ranging from the visible to the long near infrared. Prospects for the extension to mid infrared wavelengths and applications are also presented and discussed.", "author_names": [ "Pascual Munoz", "Jose David Domenech", "Carlos Dominguez", "Ana M Sanchez", "Gloria Mico", "Luis A Bru", "Daniel Perez", "Daniel Pastor" ], "corpus_id": 21209228, "doc_id": "21209228", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "State of the art of Silicon Nitride photonics integration platforms", "venue": "2017 19th International Conference on Transparent Optical Networks (ICTON)", "year": 2017 }, { "abstract": "We describe the design and performance of waveguide mixers at 1.4 THz and 1.9 THz based on NbTiN phonon cooled hot electron bolometers (HEBs) fabricated on a 2 mum thick Si3N4 membrane. The membrane is bonded to a silicon frame in the mixer block using a flip chip process. Simulated RF coupling is compared with experimental results, showing good agreement. Receiver noise temperature measurements show uncorrected values of 1600 K at 1.4 THz and 2100 K at 1.9 THz, both at 1.5GHz intermediate frequency. Device cooling on the membrane seems not to be problematic. The mixers are used in receivers for the Stratospheric Observatory for Infrared Astronomy (SOFIA) [German REceiver At THz frequencies (GREAT) and the Atacama path finder experiment (APEX) [CO, N+ deuterium observations receiver (CONDOR)", "author_names": [ "P Munoz", "Sven Holger Bedorf", "Michael Brandt", "Thomas Tils", "Netty Honingh", "Karl Jacobs" ], "corpus_id": 24768703, "doc_id": "24768703", "n_citations": 26, "n_key_citations": 1, "score": 0, "title": "THz Waveguide Mixers With NbTiN HEBs on Silicon Nitride Membranes", "venue": "IEEE Microwave and Wireless Components Letters", "year": 2006 }, { "abstract": "Superconducting phonon cooled hot electron bolometer (HEB) mixers are promising heterodyne detectors for THz frequencies. KOSMA is working to develop a heterodyne receiver for the GREAT receiver on SOFIA for observation at 1.7 1.9 THz using waveguide mixers. Waveguide mixers at these frequencies require very thin device substrates. We report on recent progress in fabricating and characterizing mixers on 2mm thick silicon nitride membranes which are suspended in a substrate channel. Heterodyne measurements with receiver noise temperatures of 1000K at 800GHz RF and 1GHz IF, at a 4.2K bath temperature show that fabrication of phonon cooled HEBs on membranes is possible with a good noise performance. The HEB device was fabricated at KOSMA and consists of a 3 5nm thin NbTiN film on an AlN buffer layer.", "author_names": [ "P Munoz", "Sven Holger Bedorf", "Michael Brandt", "Thomas Tils", "Netty Honingh", "Karl Jacobs" ], "corpus_id": 122848296, "doc_id": "122848296", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Fabrication and characterization of phonon cooled hot electron bolometers on freestanding 2 mm silicon nitride membranes for THz applications", "venue": "SPIE Astronomical Telescopes Instrumentation", "year": 2004 }, { "abstract": "Because of the demand for advanced measurement systems in the field of modern photonic integrated circuits, optical frequency domain reflectometry (OFDR) is a robust technique for characterizing design to fabrication deviations. In this paper we report an OFDR device where the interferometric part is monolithically integrated along with the device under test. We discuss the advantages in terms of compactness and performance, and the importance of the incorporated dispersion de embedding mechanism. Experimental validation is carried out by interrogating an arrayed waveguide grating on a silicon nitride platform. The results establish the proposed device as a first step in the quest for a universal test structure for integrated devices.", "author_names": [ "Luis A Bru", "Daniel Pastor", "Pascual Munoz" ], "corpus_id": 53774886, "doc_id": "53774886", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Integrated optical frequency domain reflectometry device for characterization of complex integrated devices.", "venue": "Optics express", "year": 2018 }, { "abstract": "Abstract Automated, controlled fluid delivery is an important operation in micro total analysis systems (mTAS) Actuated micro valves have been proposed to separate a pressurized fluid from the channel to be filled. This scheme greatly reduced the energy required to move the fluid. The design, micro fabrication and performance of arrays of single use valve, which constitute an integral part of this actuation mechanism, is presented. The addressable constituent of the valve is a thin metallic ohmic resistor, whose design dictates the actuation voltage. The resistor is patterned on a silicon nitride membrane that constitutes the flow barrier, which stands on a silicon wafer. Rapid heating via an electric pulse induces thermal stresses in the membrane/resistor, which in turn breaks the membrane opening the valves. The chosen processing steps allow for wafer level device fabrication using standard MEMS processing tools. Different size membranes with various thicknesses (1, 2 and 3 mm) are tested. Valves that withstand a pressure differential of up to 5 bar (3 mm x 3 mm, 3 mm thick silicon nitride membranes) were chosen for the study. Investigated valves were activated with a potentials ranging between 14 and 140 V and required activation energies from tens to hundreds of milliJoules.", "author_names": [ "Andres M Cardenas-Valencia", "Jay Dlutowski", "John Bumgarner", "Christel M Munoz", "Weidong Wang", "Raghuram Popuri", "Larry Langebrake" ], "corpus_id": 110337540, "doc_id": "110337540", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Development of various designs of low power, MEMS valves for fluidic applications", "venue": "", "year": 2007 }, { "abstract": "Despite their steady improvement over the last decades, the present UV detectors exhibit some limitations inherent to their silicon technology. Yet, the utmost spatial resolution, temporal cadence, sensitivity and photometric accuracy will be decisive for the forthcoming space solar missions. The advent of novel diamond or nitride imagers would surmount many current weaknesses, thus opening up new prospects and making the instruments cheaper. As for projects like the Solar Probe of NASA, or the Solar Orbiter of ESA, the aspiration for diamond UV detectors is still more sensible since these spacecrafts will approach very near to the Sun where the heat and the radiation fluxes are tremendously high. This triggered the initiative of an original R and T programme entitled BOLD described in this paper. We depict motivations and intentions and report on dedicated experiments with several devices under EUV synchrotron light, NUV laser and micro Raman spectroscopy.", "author_names": [ "Jean-Francois Hochedez", "Philippe Bergonzo", "M C Castex", "Pierre Dhez", "Olivier R Hainaut", "M Sacchi", "Jose L Alvarez", "Howard Boyer", "Alain Deneuville", "Pierre J L Gibart", "Benoit Guizard", "J-P Kleider", "Philippe C Lemaire", "Christine Mer", "Eva Monroy", "E Munoz", "Pierre Muret", "Franck Omnes", "Jose Luis Pau", "Victor G Ralchenko", "Dominique Tromson", "Erwin Verwichte", "Jean Claude Vial" ], "corpus_id": 121407171, "doc_id": "121407171", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Diamond UV detectors for future solar physics missions", "venue": "", "year": 2001 }, { "abstract": "The current development status of NiobiumTitanium Nitride (NbTiN) HEB mixers, for example for the GREAT receiver on SOFIA, is presented for both waveguide and quasi optical mixers for 0.8, 1.9 and 2.7 THz LO frequency. For the waveguide mixers at 0.8 and 1.9 THz the HEBs are made on 2mm thick silicon nitride membranes which are suspended in a substrate channel perpendicular to the waveguide. For the quasi optical mixer at 2.7 THz the devices are fabricated on Si substrates and are integrated into spiraland doubleslot antennas and used with an extended hemispherical silicon lens. Our measurements show that the waveguide/membrane mixers work well at both 800 GHz and 1.9 THz. To increase the required IF bandwidth we are developing thin NbN films. The first results of the NbN thin film development are presented in the paper.", "author_names": [ "Sven Holger Bedorf", "P Munoz", "Thomas Tils", "Cornelia E Honingh", "Karl Jacobs" ], "corpus_id": 55249153, "doc_id": "55249153", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Development of Phonon Cooled NbTiN HEB Heterodyne Mixers for GREAT", "venue": "", "year": 2005 }, { "abstract": "We report and characterize low temperature, plasma deposited deuterated silicon nitride films for nonlinear integrated photonics. With a peak processing temperature less than 300degC, it is back end compatible with complementary metal oxide semiconductor substrates. We achieve microresonators with a quality factor of up to 1.6x106 at 1552 nm and >1.2x106 throughout l=1510 1600 nm, without annealing or stress management (film thickness of 920 nm) We then demonstrate the immediate utility of this platform in nonlinear photonics by generating a 1 THz free spectral range, 900 nm bandwidth modulation instability microresonator Kerr comb and octave spanning, supercontinuum broadened spectra.", "author_names": [ "Jeff Chiles", "Nima Nader", "Daniel D Hickstein", "Su-Peng Yu", "Travis C Briles", "David R Carlson", "Hojoong Jung", "Jeffrey M Shainline", "Scott A Diddams", "Scott B Papp", "Sae Woo Nam", "Richard P Mirin" ], "corpus_id": 4516527, "doc_id": "4516527", "n_citations": 26, "n_key_citations": 1, "score": 0, "title": "Deuterated silicon nitride photonic devices for broadband optical frequency comb generation.", "venue": "Optics letters", "year": 2018 } ]

[ { "abstract": "Graphene, an sp2 hybridized single sheet of carbon atoms organized in a honeycomb lattice, is a zero band gap semiconductor or semimetal. This emerging material has been the subject of recent intensive research due to the novelty of its structural, electronic, optical, mechanical, and magnetic properties. Due to these properties, graphene is a favorable material for the fabrication of electronic devices, transparent electrodes, spintronics devices, and a growing array of several other applications that explore the potential of this marvelous material. However, the lack of intrinsic band gap and nonmagnetic nature of graphene limit its practical applications in the widely expanding field of carbon based devices. To take advantage of the hidden potential of this material, numerous techniques have been developed to tailor its electronic and magnetic properties. These methods include the mutual interaction between graphene layer and its substrate, doping with surface adatoms, substitutional doping, vacancy creation, and edges and strain manipulation. Herein, an overview of recently emerging innovative techniques adopted to tailor the electronic and magnetic properties of graphene is presented. The limitations, possible directions for future research and applications in diverse fields of these methods are also mentioned.", "author_names": [ "Salma Nigar", "Zhongfu Zhou", "Hao Wang", "Muhammad Imtiaz" ], "corpus_id": 103332790, "doc_id": "103332790", "n_citations": 34, "n_key_citations": 0, "score": 1, "title": "Modulating the electronic and magnetic properties of graphene", "venue": "", "year": 2017 }, { "abstract": "This article reviews the basic theoretical aspects of graphene, a one atom thick allotrope of carbon, with unusual two dimensional Dirac like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron electron and electron phonon interactions in single layer and multilayer graphene are also presented.", "author_names": [ "Antonio H Castro Neto", "Francisco Guinea", "Nuno M R Peres", "Kostya S Novoselov", "Andre K Geim" ], "corpus_id": 5650871, "doc_id": "5650871", "n_citations": 16332, "n_key_citations": 331, "score": 0, "title": "The electronic properties of graphene", "venue": "", "year": 2009 }, { "abstract": "Integrated optical modulators with high modulation speed, small footprint and large optical bandwidth are poised to be the enabling devices for on chip optical interconnects. Semiconductor modulators have therefore been heavily researched over the past few years. However, the device footprint of silicon based modulators is of the order of millimetres, owing to its weak electro optical properties. Germanium and compound semiconductors, on the other hand, face the major challenge of integration with existing silicon electronics and photonics platforms. Integrating silicon modulators with high quality factor optical resonators increases the modulation strength, but these devices suffer from intrinsic narrow bandwidth and require sophisticated optical design; they also have stringent fabrication requirements and limited temperature tolerances. Finding a complementary metal oxide semiconductor (CMOS) compatible material with adequate modulation speed and strength has therefore become a task of not only scientific interest, but also industrial importance. Here we experimentally demonstrate a broadband, high speed, waveguide integrated electroabsorption modulator based on monolayer graphene. By electrically tuning the Fermi level of the graphene sheet, we demonstrate modulation of the guided light at frequencies over 1 GHz, together with a broad operation spectrum that ranges from 1.35 to 1.6 um under ambient conditions. The high modulation efficiency of graphene results in an active device area of merely 25 um2, which is among the smallest to date. This graphene based optical modulation mechanism, with combined advantages of compact footprint, low operation voltage and ultrafast modulation speed across a broad range of wavelengths, can enable novel architectures for on chip optical communications.", "author_names": [ "Ming Liu", "Xiaobo Yin", "Erick Ulin-Avila", "Baisong Geng", "Thomas Zentgraf", "Long Ju", "Feng Wang", "Xiang Zhang" ], "corpus_id": 2260490, "doc_id": "2260490", "n_citations": 2450, "n_key_citations": 49, "score": 0, "title": "A graphene based broadband optical modulator", "venue": "Nature", "year": 2011 }, { "abstract": "We describe the synthesis of bilayer graphene thin films deposited on insulating silicon carbide and report the characterization of their electronic band structure using angle resolved photoemission. By selectively adjusting the carrier concentration in each layer, changes in the Coulomb potential led to control of the gap between valence and conduction bands. This control over the band structure suggests the potential application of bilayer graphene to switching functions in atomic scale electronic devices.", "author_names": [ "Taisuke Ohta", "Aaron Bostwick", "Thomas Seyller", "Karsten Horn", "Eli Rotenberg" ], "corpus_id": 192332, "doc_id": "192332", "n_citations": 2489, "n_key_citations": 27, "score": 0, "title": "Controlling the Electronic Structure of Bilayer Graphene", "venue": "Science", "year": 2006 }, { "abstract": "Individual graphene oxide sheets subjected to chemical reduction were electrically characterized as a function of temperature and external electric fields. The fully reduced monolayers exhibited conductivities ranging between 0.05 and 2 S/cm and field effect mobilities of 2 200 cm2/Vs at room temperature. Temperature dependent electrical measurements and Raman spectroscopic investigations suggest that charge transport occurs via variable range hopping between intact graphene islands with sizes on the order of several nanometers. Furthermore, the comparative study of multilayered sheets revealed that the conductivity of the undermost layer is reduced by a factor of more than 2 as a consequence of the interaction with the Si/SiO2 substrate.", "author_names": [ "Cristina Gomez-Navarro", "Ralf Thomas Weitz", "Alexander M Bittner", "Matteo Scolari", "Alf Mews", "Marko Burghard", "Klaus Kern" ], "corpus_id": 20584333, "doc_id": "20584333", "n_citations": 2032, "n_key_citations": 21, "score": 0, "title": "Electronic transport properties of individual chemically reduced graphene oxide sheets.", "venue": "Nano letters", "year": 2007 }, { "abstract": "Recent years have seen a rapid growth of interest by the scientific and engineering communities in the thermal properties of materials. Heat removal has become a crucial issue for continuing progress in the electronic industry, and thermal conduction in low dimensional structures has revealed truly intriguing features. Carbon allotropes and their derivatives occupy a unique place in terms of their ability to conduct heat. The room temperature thermal conductivity of carbon materials span an extraordinary large range of over five orders of magnitude from the lowest in amorphous carbons to the highest in graphene and carbon nanotubes. Here, I review the thermal properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder. Special attention is given to the unusual size dependence of heat conduction in two dimensional crystals and, specifically, in graphene. I also describe the prospects of applications of graphene and carbon materials for thermal management of electronics.", "author_names": [ "Alexander A Balandin" ], "corpus_id": 16307201, "doc_id": "16307201", "n_citations": 4106, "n_key_citations": 73, "score": 0, "title": "Thermal properties of graphene and nanostructured carbon materials.", "venue": "Nature materials", "year": 2011 }, { "abstract": "Although graphite is known as one of the most chemically inert materials, we have found that graphene, a single atomic plane of graphite, can react with atomic hydrogen, which transforms this highly conductive zero overlap semimetal into an insulator. Transmission electron microscopy reveals that the obtained graphene derivative (graphane) is crystalline and retains the hexagonal lattice, but its period becomes markedly shorter than that of graphene. The reaction with hydrogen is reversible, so that the original metallic state, the lattice spacing, and even the quantum Hall effect can be restored by annealing. Our work illustrates the concept of graphene as a robust atomic scale scaffold on the basis of which new two dimensional crystals with designed electronic and other properties can be created by attaching other atoms and molecules.", "author_names": [ "Daniel C Elias", "Rahul R Nair", "T M G Mohiuddin", "S V Morozov", "Peter Blake", "M P Halsall", "Andrea C Ferrari", "Danil W Boukhvalov", "Mikhail I Katsnelson", "Andre K Geim", "Kostya S Novoselov" ], "corpus_id": 3536592, "doc_id": "3536592", "n_citations": 3141, "n_key_citations": 54, "score": 0, "title": "Control of Graphene's Properties by Reversible Hydrogenation: Evidence for Graphane", "venue": "Science", "year": 2009 }, { "abstract": "Graphene is in many respects a nanomaterial with unique properties. Here I discuss the electronic structure, transport and optical properties of graphene, and how these are utilized in exploratory electronic and optoelectronic devices. Some suggestions for needed advances are made.", "author_names": [ "Phaedon Avouris" ], "corpus_id": 5269721, "doc_id": "5269721", "n_citations": 1137, "n_key_citations": 14, "score": 0, "title": "Graphene: electronic and photonic properties and devices.", "venue": "Nano letters", "year": 2010 }, { "abstract": "Graphene, a two dimensional, single layer sheet of sp(2) hybridized carbon atoms, has attracted tremendous attention and research interest, owing to its exceptional physical properties, such as high electronic conductivity, good thermal stability, and excellent mechanical strength. Other forms of graphene related materials, including graphene oxide, reduced graphene oxide, and exfoliated graphite, have been reliably produced in large scale. The promising properties together with the ease of processibility and functionalization make graphene based materials ideal candidates for incorporation into a variety of functional materials. Importantly, graphene and its derivatives have been explored in a wide range of applications, such as electronic and photonic devices, clean energy, and sensors. In this review, after a general introduction to graphene and its derivatives, the synthesis, characterization, properties, and applications of graphene based materials are discussed.", "author_names": [ "Xiao Huang", "Zongyou Yin", "Shixin Wu", "Xiaoying Qi", "Qiyuan He", "Qichun Zhang", "Qingyu Yan", "Freddy Yin Chiang Boey", "Hua Zhang" ], "corpus_id": 27307809, "doc_id": "27307809", "n_citations": 1927, "n_key_citations": 8, "score": 0, "title": "Graphene based materials: synthesis, characterization, properties, and applications.", "venue": "Small", "year": 2011 }, { "abstract": "There is intense interest in graphene in fields such as physics, chemistry, and materials science, among others. Interest in graphene's exceptional physical properties, chemical tunability, and potential for applications has generated thousands of publications and an accelerating pace of research, making review of such research timely. Here is an overview of the synthesis, properties, and applications of graphene and related materials (primarily, graphite oxide and its colloidal suspensions and materials made from them) from a materials science perspective.", "author_names": [ "Yanwu Zhu", "Shanthi Murali", "Weiwei Cai", "Xuesong Li", "Ji Won Suk", "Jeffrey R Potts", "Rodney S Ruoff" ], "corpus_id": 205237114, "doc_id": "205237114", "n_citations": 6808, "n_key_citations": 33, "score": 0, "title": "Graphene and graphene oxide: synthesis, properties, and applications.", "venue": "Advanced materials", "year": 2010 } ]

[ { "abstract": "Developing efficient charge separation strategies is essential to achieve high power conversion efficiency in fields of chemistry, biology and material science. Herein, we develop a facile strategy for fabrication of unique wafer scale radial nanowire assemblies by exploiting shear force in rotary solution. The assembling mechanism can be well revealed by the large scale stochastic dynamics simulation. Free electrons can be rapidly generated to produce quantitatively tunable current output when the radial nanowire as semblies rotating under the magnetic field. Moreover, the photoconductive performance of the radial semiconductor nanowire assemblies can be remarkably enhanced as the electron hole recombination was retrained by the efficient charge separation under the rotating magnetic field. Such large scale unique nanowire assemblies will facilitate the design of efficient charge separation process in bio system, sensors and photocatalysis.", "author_names": [ "Jin-Long Wang", "Huijun Jiang", "Zhenbei He", "Jian-Wei Liu", "Rui Wang", "Wei-Ran Huang", "Lan-Tian Feng", "Xiyun Ren", "Zhonghuai Hou", "Shuhong Yu" ], "corpus_id": 212408533, "doc_id": "212408533", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "Radial Nanowire Assemblies under Rotating Magnetic Field Enabled Efficient Charge Separation.", "venue": "Nano letters", "year": 2020 }, { "abstract": "Nanowires are currently being developed for use in next generation solar cells. In order to produce and improve these solar cells, improved nanowire synthesis methods and non contact measurement techniques are needed. The goal of this project was to design, build, and test a fixture for measuring both axial and radial conductivity of nanowires by terahertz spectroscopy. In order to measure conductivity along both directions, an adjustable rotating fixture for holding nanowire samples was designed and manufactured. The samples prepared for testing consisted of aligned and unaligned zinc oxide nanowires grown on both quartz and silicon substrates.", "author_names": [ "Andrew Ling-Ying Belz", "Michael E Cournoyer", "Anthony Joseph Lawinger" ], "corpus_id": 78088924, "doc_id": "78088924", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Major Qualifying Projects All Years Major Qualifying Projects April 2017 Terahertz Testing Fixture", "venue": "", "year": 2019 }, { "abstract": "We report a comprehensive study of the impact of the structural properties in radial GaAs Al0.3Ga0.7As nanowire quantum well heterostructures on the optical recombination dynamics and electrical transport properties, emphasizing particularly the role of the commonly observed variations of the quantum well thickness at different facets. Typical thickness fluctuations of the radial quantum well observed by transmission electron microscopy lead to pronounced localization. Our optical data exhibit clear spectral shifts and a multipeak structure of the emission for such asymmetric ring structures resulting from spatially separated, yet interconnected quantum well systems. Charge carrier dynamics induced by a surface acoustic wave are resolved and prove efficient carrier exchange on native, subnanosecond time scales within the heterostructure. Experimental findings are corroborated by theoretical modeling, which unambiguously show that electrons and holes localize on facets where the quantum well is the thickest and that even minute deviations of the perfect hexagonal shape strongly perturb the commonly assumed 6 fold symmetric ground state.", "author_names": [ "Maximilian M Sonner", "Anna Sitek", "Lisa Janker", "Daniel Rudolph", "Daniel Ruhstorfer", "Markus Doblinger", "Andrei Manolescu", "Gerhard Abstreiter", "Jonathan J Finley", "Achim Wixforth", "Gregor Koblmuller", "Hubert J Krenner" ], "corpus_id": 129942659, "doc_id": "129942659", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Breakdown of Corner States and Carrier Localization by Monolayer Fluctuations in Radial Nanowire Quantum Wells.", "venue": "Nano letters", "year": 2019 }, { "abstract": "Abstract It is well known that rotating beams are stretched due to centrifugal forces. Accordingly, it can be speculated that the stretching effect for rotating curved beams leads to changes of the curvature. But this speculation has been not verified and reported in existing literatures. In this paper, a dynamic model of curved beams is derived by using the Absolute Nodal Coordinate Formulation based on radial point interpolation method (ANCF/RPIM) and the transient analysis of curved beams rotating at the steady state angular speed are especially performed by using the ANCF/RPIM. The results show that the curvature of curved beams is reduced due to centrifugal forces. These configuration changes have an important influence on frequency characteristics. Thus, modal analysis should take account of the configuration changes by using steady states which can be obtained in a manner of static analysis. The \"static external force\" for steady states is a non zero centrifugal force, while centrifugal forces are identically equal to zero in the original ANCF. To this end, this paper uses a floating frame to describe overall rotations of beams, and defines the nodal coordinates located on the floating frame to describe configurations of beam. Based on this description, new ANCF dynamic equations can be easily obtained by using coordinate transformation of the original ANCF dynamic equations, in which the centrifugal forces are not equal to zero. The results show that the configurations in steady and transient states are very close, and transient states are almost located in both sides of the steady state. Therefore, steady states can be regarded approximately as equilibrium positions of vibrational curved beams. By using steady states, the new ANCF dynamic equations can be linearized to determine frequencies of curved beams. Finally, the effects of curvature changes on the frequencies of curved beams, especially \"dynamic softening\" effect, are investigated, and the reason that these effects are caused in curved beams is explained in detail.", "author_names": [ "Yuanzhao Chen", "Dingguo Zhang", "Liang Li" ], "corpus_id": 126121685, "doc_id": "126121685", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Dynamic analysis of rotating curved beams by using Absolute Nodal Coordinate Formulation based on radial point interpolation method", "venue": "Journal of Sound and Vibration", "year": 2019 }, { "abstract": "ZnO CuxO core shell radial heterojunction nanowire arrays were fabricated by a straightforward approach which combine two simple, cost effective and large scale preparation methods: (i) thermal oxidation in air of a zinc foil for obtaining ZnO nanowire arrays and (ii) radio frequency magnetron sputtering for covering the surface of the ZnO nanowires with a CuxO thin film. The structural, compositional, morphological and optical properties of the high aspect ratio ZnO CuxO core shell nanowire arrays were investigated. Individual ZnO CuxO core shell nanowires were contacted with Pt electrodes by means of electron beam lithography technique, diode behaviour being demonstrated. Further it was found that these n p radial heterojunction diodes based on single ZnO CuxO nanowires exhibit a change in the current under UV light illumination and therefore behaving as photodetectors.", "author_names": [ "Andreea Costas", "Camelia Florica", "Nicoleta Preda", "Nicoleta Georgiana Apostol", "Andrei Kuncser", "Andrei Nitescu", "Ionut Enculescu" ], "corpus_id": 93001490, "doc_id": "93001490", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Radial heterojunction based on single ZnO CuxO core shell nanowire for photodetector applications", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "Nanowires (NWs) with radial p i n junction have advantages, such as large junction area and small influence from the surface states, which can lead to highly efficient material use and good device quantum efficiency. However, it is difficult to make high quality core shell NW devices, especially single NW devices. Here, the key factors during the growth and fabrication process that influence the quality of single core shell p i n NW devices are studied using GaAs(P) NW photovoltaics as an example. By p doping and annealing, good ohmic contact is achieved on NWs with a diameter as small as 50 60 nm. Single NW photovoltaics are subsequently developed and a record fill factor of 80.5% is shown. These results bring valuable information for making single NW devices, which can further benefit the development of high density integration circuits.", "author_names": [ "Yunyan Zhang", "Ana M Sanchez", "Martin Aagesen", "Suguo Huo", "H Aruni Fonseka", "James A Gott", "Dongyoung Kim", "Xuezhe Yu", "Xingyou Chen", "Jia Xu", "Tianyi Li", "Haotian Zeng", "Giorgos Boras", "Huiyun Liu" ], "corpus_id": 58768765, "doc_id": "58768765", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Growth and Fabrication of High Quality Single Nanowire Devices with Radial p i n Junctions.", "venue": "Small", "year": 2019 }, { "abstract": "Semiconductors are essential for modern electronic and optoelectronic devices. To further advance the functionality of such devices, the ability to fabricate increasingly complex semiconductor nanostructures is of utmost importance. Nanowires offer excellent opportunities for new device concepts; heterostructures have been grown in either the radial or axial direction of the core nanowire but never along both directions at the same time. This is a consequence of the common use of a foreign metal seed particle with fixed size for nanowire heterostructure growth. In this work, we present for the first time a growth method to control heterostructure growth in both the axial and the radial directions simultaneously while maintaining an untapered self seeded growth. This is demonstrated for the InAs/InAs1 xPx material system. We show how the dimensions and composition of such axio radial nanowire heterostructures can be designed including the formation of a \"pseudo superlattice\" consisting of five separate InAs1 xPx segments with varying length. The growth of axio radial nanowire heterostructures offers an exciting platform for novel nanowire structures applicable for fundamental studies as well as nanowire devices. The growth concept for axio radial nanowire heterostructures is expected to be fully compatible with Si substrates.", "author_names": [ "Bernhard Mandl", "Mario Keplinger", "Maria E Messing", "Dominik Kriegner", "Reine Wallenberg", "Lars Samuelson", "G Bauer", "J Stangl", "Vaclav Holy", "Knut Deppert" ], "corpus_id": 206744144, "doc_id": "206744144", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Self Seeded Axio Radial InAs InAs1 xPx Nanowire Heterostructures beyond \"Common\" VLS Growth.", "venue": "Nano letters", "year": 2018 }, { "abstract": "The electrical and optical properties of low dimensional nanostructures depend critically on size and geometry and may differ distinctly from those of their bulk counterparts. In particular, ultrathin semiconducting layers as well as nanowires have already proven the feasibility to realize and study quantum size effects enabling novel ultrascaled devices. Further, plasmonic metal nanostructures attracted recently a lot of attention because of appealing near field mediated enhancement effects. Thus, combining metal and semiconducting constituents in quasi one dimensional heterostructures will pave the way for ultrascaled systems and high performance devices with exceptional electrical, optical, and plasmonic functionality. This Letter reports on the sophisticated fabrication and structural properties of axial and radial Al Ge and Al Si nanowire heterostructures, synthesized by a thermally induced exchange reaction of single crystalline Ge Si core shell nanowires and Al pads. This enables a self aligned metallic contact formation to Ge segments beyond lithographic limitations as well as ultrathin semiconducting layers wrapped around monocrystalline Al core nanowires. High resolution transmission electron microscopy, energy dispersive X ray spectroscopy, and m Raman measurements proved the composition and perfect crystallinity of these metal semiconductor nanowire heterostructures. This exemplary selective replacement of Ge by Al represents a general approach for the elaboration of radial and axial metal semiconductor heterostructures in various Ge semiconductor heterostructures.", "author_names": [ "Masiar Sistani", "Minh Anh Luong", "Martien I den Hertog", "Eric Robin", "Maria Spies", "Bruno Fernandez", "J Yao", "Emmerich Bertagnolli", "Alois Lugstein" ], "corpus_id": 53424054, "doc_id": "53424054", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Monolithic Axial and Radial Metal Semiconductor Nanowire Heterostructures.", "venue": "Nano letters", "year": 2018 }, { "abstract": "Nanowires have the potential to play an important role for next generation light emitting diodes. In this work, we present a growth scheme for radial nanowire quantum well structures in the AlGaInP material system using a GaInP nanowire core as a template for radial growth with GaInP as the active layer for emission and AlGaInP as charge carrier barriers. The different layers were analyzed by X ray diffraction to ensure lattice matched radial structures. Furthermore, we evaluated the material composition and heterojunction interface sharpness by scanning transmission electron microscopy energy dispersive X ray spectroscopy. The electro optical properties were investigated by injection luminescence measurements. The presented results can be a valuable track toward radial nanowire light emitting diodes in the AlGaInP material system in the red/orange/yellow color spectrum.", "author_names": [ "Alexander H Berg", "S Yazdi", "Ali Nowzari", "Kristian Storm", "Vandana Jain", "Neimantas Vainorius", "Lars Samuelson", "Jakob B Wagner", "M T Borgstrom" ], "corpus_id": 206730973, "doc_id": "206730973", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Radial Nanowire Light Emitting Diodes in the (AlxGa1 x)yIn1 yP Material System.", "venue": "Nano letters", "year": 2016 }, { "abstract": "Abstract This paper studies flow and heat transfer of nanofluids over a rotating disk with uniform stretching rate. Three types of nanoparticles Cu, Al2O3 and CuO with water based nanofluids are considered. The governing equations are reduced by Von Karman transformation and then solved by the homotopy analysis method (HAM) which is in close agreement with numerical results. Results indicate that with increasing in stretching strength parameter, the skin friction and the local Nusselt number, the velocity in radial and axial directions increase, whereas the velocity in tangential direction and the thermal boundary layer thickness decrease, respectively. Moreover, the effects of volume fraction and types of nanofluids on velocity and temperature fields are also analyzed.", "author_names": [ "Chenguang Yin", "Liancun Zheng", "Chaoli Zhang", "Xinxin Zhang" ], "corpus_id": 125560614, "doc_id": "125560614", "n_citations": 76, "n_key_citations": 0, "score": 0, "title": "Flow and heat transfer of nanofluids over a rotating disk with uniform stretching rate in the radial direction", "venue": "", "year": 2017 } ]

[ { "abstract": "Piezoelectric microelectromechanical systems (MEMS) offer the opportunity for high sensitivity sensors and large displacement, low voltage actuators. In particular, recent advances in the deposition of perovskite thin films point to a generation of MEMS devices capable of large displacements at complementary metal oxide semiconductor compatible voltage levels. Moreover, if the devices are mounted in mechanically noisy environments, they also can be used for energy harvesting. Key to all of these applications is the ability to obtain high piezoelectric coefficients and retain these coefficients throughout the microfabrication process. This article will review the impact of composition, orientation, and microstructure on the piezoelectric properties of perovskite thin films such as PbZr 1 x Ti x O 3 (PZT) Superior piezoelectric coefficients e 31, f of 18 C/m 2 are achieved in {001} oriented PbZr 0.52 Ti 0.48 O 3 films with improved compositional homogeneity on Si substrates. The advent of such high piezoelectric responses in films opens up a wide variety of possible applications. A few examples of these, including low voltage radio frequency MEMS switches and resonators, actuators for millimeter scale robotics, droplet ejectors, energy scavengers for unattended sensors, and medical imaging transducers, will be discussed.", "author_names": [ "Paul Muralt", "Ronald Polcawich", "Susan E Trolier-McKinstry" ], "corpus_id": 111283387, "doc_id": "111283387", "n_citations": 218, "n_key_citations": 5, "score": 1, "title": "Piezoelectric Thin Films for Sensors, Actuators, and Energy Harvesting", "venue": "", "year": 2009 }, { "abstract": "Perovskite oxide materials have been widely investigated due to properties related to their spontaneous polarization such as ferroelectricity, piezoelectricity, and pyroelectricity. Often due to high chemical stability, and mechanical robustness with large dielectric constants, ferroelectric and piezoelectric perovskite oxides have become essential components in a wide spectrum of applications such as nonvolatile random access memory, microelectromechanical devices, sensors, actuators, high frequency electrical components, tunable microwave circuits, nanogenerators for energy harvesting, and as potential solar cell absorbers. The realization of miniaturized devices has required these materials to be investigated in thin film forms. However, research in ferroelectric and piezoelectric thin films is limited due to the intrinsic difficulties of structural engineering at the nanoscale. To this end, nanostructured films exhibit uniquely different properties from nontextured homogenous thin films due to the deliberate engineering of nanoscale features into the structure. Moreover, nanostructuring provides new insights into the size, shape, and surface effects on the charge ordering in ferroelectric and piezoelectric perovskite oxide materials. The down scaling effect results in an enhancement of the surface area of materials where surface charges play a dominant role in determining the magnitude and direction of polarization. As polarization properties are the cumulative phenomenon of crystal dimensions, orientation, and ordering, synthesis methodologies that can lead to the manipulation of size and dimensions of ferro and piezoelectric nanostructures can offer great advantages. However, the large scale synthesis and integration of ordered functional nanowires is a challenge, due to their complicated fabrication methodologies, high cost, and difficulties with phase stability in many metastable perovskite compounds. In this chapter we will review how facile solution based synthesis processes can be utilized for fabricating state of the art and novel perovskite nanostructured films where tuning crystallinity and strain engineering due to interfacial effects, dimensional confinement, and domain wall interaction resulting from grain boundaries in nanostructures may enhance the Curie temperature, permittivity, or polarizability, and induce \"self poling\" effects, eventually enhancing the overall performance of the devices. We will also consider the potential of some of the new ferroelectric nanostructures for photovoltaic applications, proposing pathways for coherent design of next generation sustainable energy devices.", "author_names": [ "Anuja Datta", "Debarati Mukherjee", "Sohini Kar-Narayan" ], "corpus_id": 139156431, "doc_id": "139156431", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Ferroelectric and piezoelectric oxide nanostructured films for energy harvesting applications", "venue": "", "year": 2018 }, { "abstract": "Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small scale vibrations and may possess superior mechanical to electrical conversion efficiency when compared to bulk or thin film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density) Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires ~tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance <1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients eS and eT, based on intrinsic materials properties, for comparing piezoelectric NG performance under strain driven and stress driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain driven NGs while polymers are more promising for stress driven NGs. Our work offers a viable means of comparing NG materials and devices on a like for like basis that may be useful for designing and optimizing nanoscale piezoelectric energy harvesters for specific applications. S Online supplementary data available from stacks.iop.org/NANO/26/344001/mmedia", "author_names": [ "Asif Khan", "Zafar Abas", "Heung Soo Kim", "Il-Kwon Oh" ], "corpus_id": 29344859, "doc_id": "29344859", "n_citations": 114, "n_key_citations": 2, "score": 0, "title": "Piezoelectric thin films: an integrated review of transducers and energy harvesting", "venue": "", "year": 2015 }, { "abstract": "Abstract Partial substitution of aluminium by scandium in the wurtzite structure of aluminium nitride (AlN) leads to a large increase of the piezoelectric response by more than a factor of 2. Therefore, aluminium scandium nitride (ASN) thin films attracted much attention to improve piezoelectric MEMS devices such as RF filters, sensors, micro actuators and energy harvesting devices. In this work, process microstructure property relationships of ASN thin films containing up to 42% Sc were investigated. Like AlN thin films, ASN films are sputter deposited at 300 350degC with pulsed DC powered magnetrons. The influence of the process parameters on the film structure, the intrinsic stress and the piezoelectric response was investigated in order to achieve optimal piezoelectric coefficients up to high Sc concentrations. X Ray diffraction (XRD) and transmission electron microscopy (TEM) were used to analyse the quality of c axis texture. The films showed exclusively (002) texture with rocking curve widths in the range of 1.3 2deg (FHWM) The films were further analysed by scanning electron microscopy (SEM) The Sc content was determined by energy dispersive X ray spectroscopy (EDX) A good compositional homogeneity in the range of 0.5 1 at. was achieved between border and centre of 200 mm wafers. So far, we obtained ASN films with transversal piezoelectric coefficients of up to e31,f 2.77 C/m2, which is a factor 2.6 higher than in pure AlN thin films.", "author_names": [ "Stefan Mertin", "Bernd Heinz", "Oliver Rattunde", "Gabriel Christmann", "Marc Dubois", "Sylvain Nicolay", "Paul Muralt" ], "corpus_id": 139678784, "doc_id": "139678784", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Piezoelectric and structural properties of c axis textured aluminium scandium nitride thin films up to high scandium content", "venue": "", "year": 2018 }, { "abstract": "Aluminium scandium nitride (ASN) exhibits a largely enhanced piezoelectric response as compared to aluminium nitride (AlN) which makes it an upcoming piezoelectric material for next generation RF filters, sensors, actuators and energy harvesting devices. In this work, process microstructure property relationships of such ASN films containing up to 40 at% Sc were investigated. Hereby, the influence of the process parameters on the film structure, the intrinsic stress and the piezoelectric response was carefully investigated.", "author_names": [ "Stefan Mertin", "Vladimir P Pashchenko", "Fazel Parsapour", "Cosmin Silviu Sandu", "Bernd Heinz", "Oliver Rattunde", "Gabriel Christmann", "Marc Dubois", "Paul Muralt" ], "corpus_id": 23994897, "doc_id": "23994897", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Enhanced piezoelectric properties of c axis textured aluminium scandium nitride thin films with high scandium content: Influence of intrinsic stress and sputtering parameters", "venue": "2017 IEEE International Ultrasonics Symposium (IUS)", "year": 2017 }, { "abstract": "Aluminium scandium nitride (ASN) exhibits a largely enhanced piezoelectric response as compared to aluminium nitride (AlN) which makes it an upcoming piezoelectric material for use in next generation RF filters, sensors, actuators and energy harvesting devices. In this work, process microstructure property relationships of such sputtered ASN films containing up to 42 at% Sc were investigated. Hereby, the influence of the process parameters on the film structure, the intrinsic stress and the piezoelectric response were carefully investigated. A high piezoelectric response (e31, f 2.67 C/m2 and d33, f 10.3 pm/V) was measured for films with 42 at% and 34 at% Sc, respectively. The results are very promising towards industrial applications.", "author_names": [ "Stefan Mertin", "Vladimir P Pashchenko", "Fazel Parsapour", "Clemens Nyffeler", "Cosmin Silviu Sandu", "Bernd Heinz", "Oliver Rattunde", "Gabriel Christmann", "Marc Dubois", "Paul Muralt" ], "corpus_id": 47576233, "doc_id": "47576233", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Enhanced piezoelectric properties of c axis textured aluminium scandium nitride thin films with high scandium content: Influence of intrinsic stress and sputtering parameters", "venue": "2017 IEEE International Ultrasonics Symposium (IUS)", "year": 2017 }, { "abstract": "This is a review of a part of the work of the Technological Design Group at Technical University of Sofia, Faculty of Electronic Engineering and Technologies, Department of Microelectronics. It is dealing with piezoelectric polymer materials and their application in different microsystems (MEMS) and Energy Harvesting Devices (EHD) some organic materials and their applications in organic (OLED) displays, some transparent conductive materials etc. The metal oxides Lead Zirconium Titanate (PZT) and Zinc Oxide (ZnO) are used as piezoelectric layers driving part of different sensors, actuators and EHD. These materials are studied in term of their performance in dependence on the deposition conditions and parameters. They were deposited as thin films by using RF Sputtering System. As technological substrates, glass plates and Polyethylenetherephtalate (PET) foils were used. For characterization of the materials, a test structure, based on Surface Acoustic Waves (SAW) was designed and prepared. The layers were characterized by Fourier Transform Infrared spectroscopy (FTIR) The piezoelectric response was tested at variety of mechanical loads (tensile strain, stress) in static and dynamic (multiple bending) mode. The single layered and double layered structures were prepared for piezoelectric efficiency increase. A structure of piezoelectric energy transformer is proposed and investigated.", "author_names": [ "Krassimir H Denishev" ], "corpus_id": 115031957, "doc_id": "115031957", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Some metal oxides and their applications for creation of Microsystems (MEMS) and Energy Harvesting Devices (EHD)", "venue": "", "year": 2016 }, { "abstract": "Piezoelectric materials are essential for harvesting energy from mechanical vibrations. Thin films of piezoelectric materials including AlN and binary perovskite compounds PZT are widely studied for a fabrication of energy harvesting MEMS. The piezoelectric materials have held a key position in the energy harvesting devices. Varieties of bulk piezoelectric ceramic materials are studied and used in practice for the piezoelectric sensors and/or actuators. However, piezoelectric properties of the thin film materials are different from bulk properties due to their structural differences. The characters of the thin film piezoelectric materials are not fully understood yet. For making a better energy harvesting device, a fundamental discussion will be necessary for the thin film piezoelectric materials. In this paper, first the fundamentals of thin film piezoelectric materials and the process design are discussed, and then novel piezoelectric thin films of PZT based ternary perovskite compounds are proposed as an example for making the improved energy harvesting MEMS.", "author_names": [ "Kiyotaka Wasa", "Isaku Kanno", "Hidetoshi Kotera" ], "corpus_id": 53370941, "doc_id": "53370941", "n_citations": 20, "n_key_citations": 1, "score": 0, "title": "FUNDAMENTALS OF THIN FILM PIEZOELECTRIC MATERIALS AND PROCESSING DESIGN FOR A BETTER ENERGY HARVESTING MEMS", "venue": "", "year": 2009 }, { "abstract": "Piezoelectric materials have received considerable attention from the smart structure community because of their potential use as sensors, actuators and power harvesters. In particular, polyvinylidene fluoride (PVDF) has been proposed in recent years as an enabling material for a variety of sensing and energy harvesting applications. In this study, carbon nanotubes (CNT) are included within a PVDF matrix to enhance the properties of PVDF. The CNT PVDF composite is fabricated by solvent evaporation and melt pressing. The inclusion of CNT allows the dielectric properties of the PVDF material to be adjusted such that lower poling voltages can be used to induce a permanent piezoelectric effect in the composite. To compare the piezoelectric characteristics of the CNT PVDF composite proposed, scanning electron microscope (SEM) images were analyzed and ferroelectric experiments were conducted. Finally, the aforementioned composites were mounted upon the surface of a cantilevered beam to compare the voltage generation of the CNT PVDF composite against homogeneous PVDF thin films.", "author_names": [ "Junhee Kim", "Kenneth J Loh", "Jerome P Lynch" ], "corpus_id": 16088027, "doc_id": "16088027", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Piezoelectric polymeric thin films tuned by carbon nanotube fillers", "venue": "SPIE Smart Structures and Materials Nondestructive Evaluation and Health Monitoring", "year": 2008 }, { "abstract": "Magnetoelectric (ME) thin film composites are attracting a continually increasing interest due to their unique features and potential applications in multifunctional microdevices and integrated units such as sensors, actuators and energy harvesting modules. By combining piezoelectric and highly magnetostrictive thin films, the potentialities of these materials increase. In this paper we report the fabrication of SmFe2 and PZT thin films and the investigation of their properties. First of all, a 400 nm thin SmFe film was deposited on top of Si/SiO2 substrate by magnetron sputter deposition. Afterwards, a 140 nm Pt bottom electrode was sputtered on top of the SmFe film forming a bottom electrode. Spin coating was employed for the deposition of the 150 nm thin PZT layer. A PZT solution with 10 %Pb excess was utilized for this fabrication step. Finally, circular Pt top electrodes were sputtered as top electrodes. This paper focuses on the microstructure of the individual films characterized by X Ray diffractometer (XRD) and scanning electron microscopy (SEM) A piezoelectric evaluation system, aixPES, with TF2000E analyzer component was used for the electric hysteresis measurements of PZT thin films and a vibrating sample magnetometer (VSM) was employed for the magnetic characterization of the SmFe. The developed thin films and the fabricated double layer SmFe PZT exhibit both good ferromagnetic and piezoelectric responses which predict a promising ME composite structure. The quantitative chemical composition of the samples was confirmed by energy dispersive spectroscopy (EDX)", "author_names": [ "Ioanna Giouroudi", "Mohammed Alnassar", "Juergen Kosel" ], "corpus_id": 52036192, "doc_id": "52036192", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fabrication and properties of SmFe2 PZT magnetoelectric thin films", "venue": "Microtechnologies for the New Millennium", "year": 2013 } ]

[ { "abstract": "Today, nanoparticles have attracted the attention of many researchers due to their special properties as well as their many technological applications. Among these, titanium dioxide nanoparticles have many important applications in various industries due to their excellent optical, electrical and catalytic properties. These applications include use in industrial pigments, as photocatalysts in environmental cleansing, in sunscreens to protect the skin, in photovoltaic applications for solar cells, sensors, in electronic device components, and many more. Two important properties of this material that make it very efficient and useful in life are its photocatalytic and superhydrophobic properties. These two properties are used to purify water and wastewater, eliminate air pollution and buildings, accelerate photochemical reactions such as hydrogen production, fabricate surfaces and layers and self cleaning glass. The properties of titanium dioxide nanoparticles are strongly dependent on the size of the doped particles, elements or compounds and the surface modifications made on them, which in turn are influenced by the nanoparticle synthesis method. For this reason, methods for the synthesis of titanium dioxide nanoparticles have received much attention today. As the size of the material gets smaller and smaller and reaches the nanoscale, new physical and chemical properties show up. Among the unique properties of nanomaterials, the motion of electrons and holes in semiconductor nanomaterials is dominated by quantum constraint, and the transfer properties of phonons and photons are strongly influenced by the size and geometry of the material. The effective surface area and surface to volume ratio increase with decreasing the material size. High effective levels are achieved by small particles, which will be useful in many 2TiO based types of equipment in which the interaction of the common surface of the material is important.", "author_names": [ "Chen Luo", "Jingting Li", "Jie Xu" ], "corpus_id": 233363768, "doc_id": "233363768", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Comparative Study of Post Marriage Nationality Of Women in Legal Systems of Different Countries", "venue": "", "year": 2020 }, { "abstract": "OBJECTIVE Vulvovaginal health is important to women's overall health, fertility, sexuality, self perception, self confidence and intimacy. It is important to identify the existing perceptions and levels of knowledge about intimate care practices from women in different countries, and with different cultures, religions, and perspectives to help women overcome barriers to optimal intimate care. METHODS An anonymous online survey about general and intimate hygiene routines/habits was distributed across 10 countries (England, France, Germany, Italy, Portugal, Russia, China, Philippines, Taiwan, Thailand) The sample consisted of around 10,000 women (aged 18 to 60 years) recruited through an online panel. RESULTS The survey indicates that for many women, cleaning the intimate area is not just about hygiene, but also about taking care of themselves. Intimate care practices, performed daily, varies widely among the countries (from 38% to 91% Italy, Philippines Portugal, Russia and Thailand were the countries with higher percentage. Intimate care is mainly associated with hygiene and health benefit, but interestingly women engage in intimate care more often with age. Most women worldwide are comfortable talking about female genitalia but still consider it a taboo topic, particularly among younger generations. Asian countries continue to carry negative connotations. CONCLUSIONS This survey is the first of its kind for number of women involved in this research and for multi cultural design. Women perceive that practicing intimate care positively impacts their health and wellbeing. However, intimate care is still not one of the most frequent daily routines for many women.", "author_names": [ "Prof Filippo Murina", "Alessandra Graziottin", "Odile Bagot", "Nick Panay", "Manopchai Thamkhantho", "Steven W Shaw" ], "corpus_id": 235661894, "doc_id": "235661894", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Real World Practices and Attitudes Towards Intimate Self Care: Results From An International Women's Survey.", "venue": "Journal of gynecology obstetrics and human reproduction", "year": 2021 }, { "abstract": "Aim To determine the level of knowledge of periodontal diseases, practices regarding oral hygiene, and self perceived periodontal problems among pregnant and postnatal women attending reproductive and child health clinics in rural districts of Zambia. Methodology This was a quantitative, questionnaire based, descriptive, and cross sectional study that recruited 410 women aged 15 to 43 years. Data were analyzed using SPSS v19.0 computer program. Results Participants knowledgeable of periodontal diseases were 62% gingivitis signs included gum swelling (87.4% and bleeding (93.3% Of all participants, 95.6% practiced tooth brushing: twice/day (38.5% using plastic toothbrush (95.6% chewing stick (12.2% toothpick (10.7% dental floss (2.0% and tongue cleaning (55.4% Self reported periodontal problems were bleeding gums (23.2% gums that were reddish (10.5% swollen (11.0% painful (15.9% and mobile teeth (3.4% In logistic regression analysis, painful gums, reddish gums, and toothpick use were 21.9, 4.7, and 4.3 respectively, significantly more likely to cause gum bleeding on tooth brushing. Conclusions Most studied women had general knowledge of periodontal diseases but only few knew the cause. All participants performed tooth cleaning; however, majority did not know appropriate practices, and only few had periodontal problems. Integration of oral health to general health promotion and periodontal therapy to pregnant women at high risk is recommended.", "author_names": [ "T M Kabali", "E G Mumghamba" ], "corpus_id": 52112007, "doc_id": "52112007", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Knowledge of Periodontal Diseases, Oral Hygiene Practices, and Self Reported Periodontal Problems among Pregnant Women and Postnatal Mothers Attending Reproductive and Child Health Clinics in Rural Zambia", "venue": "International journal of dentistry", "year": 2018 }, { "abstract": "BACKGROUND Women can experience symptoms of gingival inflammation during pregnancy. However, whether clinical signs of gingival inflammation were present already before pregnancy and whether women perceive an alteration in their periodontal health status during pregnancy compared to their periodontal health status before pregnancy remain unclear. OBJECTIVES The aim of this study was to evaluate the self reported periodontal conditions in pregnant Dutch women as perceived before and during pregnancy. METHODS This cross sectional survey was performed by asking women visiting two midwifery practices to complete a structured questionnaire. The data, which considered the women's oral hygiene habits, perceived periodontal health status before and during pregnancy and dental visits, were gathered and analysed. Parametric and nonparametric tests were used when appropriate. RESULTS Most of the respondents (mean age: 29.6 years) brushed their teeth twice a day (72.2% and 62.0% used interdental cleaning devices. Significant differences in periodontal health before and during pregnancy were perceived. No differences with respect to periodontal disease symptoms between the three trimesters during pregnancy were found. The symptom with the greatest increase was bleeding gums. This was followed by symptoms of painful and swollen gums. Of the 61.5% women who disclosed their plans to become pregnant to their dental care practitioner, 53.9% received information regarding the possibility of alterations in oral health status during pregnancy. Because of the perceived alterations in oral health status during pregnancy, approximately 11% of the women scheduled an additional appointment with their dental care professional for advice. CONCLUSION During the pregnancy period, perceived alterations in periodontal health status were reported as compared to the oral health situation before pregnancy. Furthermore, approximately 50% of the women who visited a dental professional and disclosed their (plans) of pregnancy did not receive specific information concerning their periodontal health during pregnancy.", "author_names": [ "Valeriya Stelmakh", "Dagmar Else Slot", "G A Fridus Van der Weijden" ], "corpus_id": 28068603, "doc_id": "28068603", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Self reported periodontal conditions among Dutch women during pregnancy", "venue": "International journal of dental hygiene", "year": 2017 }, { "abstract": "Introduction Nomads move from one settlement to another, thus it has been difficult to have adequate documentation about their oral health and that of their children. Aim To investigate the perception and practices of nomadic Fulani women toward their children's oral health. Methodology A cross sectional study was conducted among 197 Fulani women using a structured interviewer administered questionnaire. Results Perceived causes of tooth decay included tooth germs/worms (23.9% and sugar (5.1% and 32.0% 15.2% and 5.1% respectively, self medicated children with antibiotics, traditional concoctions/herbs, and analgesics for tooth decay. Two fifths (40.1% attributed bleeding gums to tooth germs/worms. Polyurethane foam (46.7% toothbrush (32.0% finger (18.8% and wooden twigs (2.5% were aids used for cleaning children's teeth. Conclusions These mothers have suboptimal oral health knowledge, attitudes, and practices toward their children's oral health. There is a need for urgent intervention among this group of people.", "author_names": [ "Olubunmi Olusola Bankole", "Folake Barakat Lawal", "Abimbola Balogun" ], "corpus_id": 38028328, "doc_id": "38028328", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Perception and Practices of Nomadic Women in a Rural Community in Southwestern Nigeria to Their Children's Oral Health", "venue": "International quarterly of community health education", "year": 2017 }, { "abstract": "BackgroundHousehold cleaning and pesticide products may contribute to breast cancer because many contain endocrine disrupting chemicals or mammary gland carcinogens. This population based case control study investigated whether use of household cleaners and pesticides increases breast cancer risk.MethodsParticipants were 787 Cape Cod, Massachusetts, women diagnosed with breast cancer between 1988 and 1995 and 721 controls. Telephone interviews asked about product use, beliefs about breast cancer etiology, and established and suspected breast cancer risk factors. To evaluate potential recall bias, we stratified product use odds ratios by beliefs about whether chemicals and pollutants contribute to breast cancer; we compared these results with odds ratios for family history (which are less subject to recall bias) stratified by beliefs about heredity.ResultsBreast cancer risk increased two fold in the highest compared with lowest quartile of self reported combined cleaning product use (Adjusted OR 2.1, 95% CI: 1.4, 3.3) and combined air freshener use (Adjusted OR 1.9, 95% CI: 1.2, 3.0) Little association was observed with pesticide use. In stratified analyses, cleaning products odds ratios were more elevated among participants who believed pollutants contribute \"a lot\" to breast cancer and moved towards the null among the other participants. In comparison, the odds ratio for breast cancer and family history was markedly higher among women who believed that heredity contributes \"a lot\" (OR 2.6, 95% CI: 1.9, 3.6) and not elevated among others (OR 0.7, 95% CI: 0.5, 1.1).ConclusionsResults of this study suggest that cleaning product use contributes to increased breast cancer risk. However, results also highlight the difficulty of distinguishing in retrospective self report studies between valid associations and the influence of recall bias. Recall bias may influence higher odds ratios for product use among participants who believed that chemicals and pollutants contribute to breast cancer. Alternatively, the influence of experience on beliefs is another explanation, illustrated by the protective odds ratio for family history among women who do not believe heredity contributes \"a lot.\" Because exposure to chemicals from household cleaning products is a biologically plausible cause of breast cancer and avoidable, associations reported here should be further examined prospectively.", "author_names": [ "Ami R Zota", "Ann Aschengrau", "Ruthann A Rudel", "Julia Green Brody" ], "corpus_id": 13530241, "doc_id": "13530241", "n_citations": 34, "n_key_citations": 5, "score": 0, "title": "Self reported chemicals exposure, beliefs about disease causation, and risk of breast cancer in the Cape Cod Breast Cancer and Environment Study: a case control study", "venue": "Environmental health a global access science source", "year": 2010 }, { "abstract": "This study aimed at determining whether oral health behavior differs between patients regularly checked by male and female dentists. The analysis was based on a cross sectional survey of 354 Japanese community residents (median age 54 years; 145 men and 209 women) conducted in a municipality from January to February 2017. Data on demographic characteristics and factors associated with oral health behavior were obtained through self administered questionnaires. The association between regular dentist gender and patients' regular dental care check up and interdental cleaning performance was examined after adjusting for potential confounders. Among respondents, 88.7% and 11.3% reported having male and female regular dentists, respectively. In a multivariate logistic regression model, patients regularly checked by female dentists had an increased likelihood of visiting their dentist for dental care check up at least once every year (odds ratio [OR] 2.23, 95% confidence interval [CI] 1.09 4.55)and using an interdental cleaner (OR 2.62, 95% CI 1.03 6.71) compared to those regularly checked by male dentists. Patients regularly checked by female dentists tended to have more preventive oral health behaviors than those regularly checked by male dentists. These findings suggest that dentist gender has important clinical implications for patients' oral health behavior.", "author_names": [ "Kenji Takeuchi", "Yuki Noguchi", "Yukie Nakai", "Toshiyuki Ojima", "Yoshihisa Yamashita" ], "corpus_id": 210950444, "doc_id": "210950444", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Dentist gender related differences in patients' oral health behaviour.", "venue": "Journal of oral science", "year": 2020 }, { "abstract": "Abstract To examine pain, occupational performance problems, and quality of life (QoL) and possible associations between these variables, 41 elderly women with acute pain due to a fracture of the upper extremity were assessed with COPM, DASH, validated questions on pain, and a global question on QoL. The participants reported 802 performance problems: 38% within self care, 52% within productivity, and 10% within leisure. Strength demanding bilateral activities in cleaning, hygiene, and cooking were most frequently reported. The median COPM performance and satisfaction scores were 2.8 and 3.4; the mean DASH score was 44.27. Pain frequency and intensity as well as QoL correlated moderately with the number of performance problems on the COPM. QoL was in general not very reduced and correlated only negligibly with pain. The DASH score correlated moderately with the total number of performance problems on the COPM and with the COPM satisfaction score, and it can be argued that a finding of a low DASH score in elderly women with upper extremity fractures should be followed up by a referral to occupational therapy. Future studies, preferably follow up studies, are called for to further explore the multiple factors leading to performance problems in women with fractures of the upper extremity and to explore possible associations between activity performance and QoL.", "author_names": [ "Merete Klindt Dekkers", "Tove Lise Nielsen" ], "corpus_id": 38992849, "doc_id": "38992849", "n_citations": 17, "n_key_citations": 2, "score": 0, "title": "Occupational performance, pain, and global quality of life in women with upper extremity fractures", "venue": "Scandinavian journal of occupational therapy", "year": 2011 }, { "abstract": "Breast cancer is one of the most frequent malignancies worldwide which is characterized by early onset and diagnosis at advanced stages in Iranian women. Increasing women's awareness and implementing breast cancer screening programs detect cancer earlier and reduce mortality. Physicians play a pivotal role in this regard. Further, there is limited literature about knowledge, attitude, and screening behaviors in Iranian women. Using a questionnaire, we assessed and compared breast cancer knowledge, attitude, and screening behaviors in 102 female physicians and 94 female non health care personnel, who were mostly from the hospital's cleaning and housekeeping sections. Of the physicians and of non health care personnel, respectively, 93.1 and 24.7 felt confident about their knowledge and 37.6 and 26.1 performed monthly breast self examination. Of physicians aged 40 and over, 31.25 and 18.75 had clinical breast examination and mammogram, respectively, within 12 months prior to date of data collection. In non health care personnel aged 40 and over, the results were 27.59 for clinical breast examination and 17.24 for mammogram at the same period of time. Despite the higher knowledge and socioeconomic class of physicians, there were no significant difference in screening behaviors between physicians and non health care personnel (P 0.05)", "author_names": [ "Maryam Kadivar", "Soodabeh Joolaee", "Azadeh Joulaee", "Nasser Bahrani", "Niloufar Raeis Hosseini" ], "corpus_id": 16249472, "doc_id": "16249472", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Breast Cancer Knowledge, Attitudes and Screening Behaviors in Two Groups of Iranian Women: Physicians and Non health Care Personnel", "venue": "Journal of Cancer Education", "year": 2012 }, { "abstract": "This chapter presents seven cases of social entrepreneurs, to illustrate the need for the phenomenon of social entrepreneurship in our increasingly intertwining global society. The seven cases are the following: (1) Kenton Lee's Shoe that Grows in the US, inspired by children without shoes in Kenya, (2) Andy Moon's Sunfarmer solar energy project, inspired by healthcare and farming energy problems in Nepal, (3) Jeremiah Kimbugwe's sanitary napkin operation to enhance women's participation in education and professional development in Uganda, (4) Luis Cruz' Eyeboard system to assist physically disabled persons in Honduras, (5) William Kamkwamba's construction of electricity resources to ensure energy in his village in Malawi, (6) Brittany Wenger's artificial brain to timely help detect cancer in the US, and (7) Arpit Dhupar's self cleaning trap for particulate matter emissions from the combustion of fossil fuels, to reduce pollution in India. Each of the cases will briefly be evaluated on the basis of three aspects to determine social entrepreneurship: (1) the predominance of a social mission, (2) the importance of innovation, and (3) the role of earned income.", "author_names": [ "Joan F Marques" ], "corpus_id": 226559909, "doc_id": "226559909", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Case for Social Entrepreneurship in Our Times", "venue": "", "year": 2020 } ]

[ { "abstract": "Abstract In this paper we describe a new photoacoustic cell design that allows simultaneous photoacoustic and photoconductive measurements of solid semiconductor samples. The two techniques are complementary. Photoacoustic spectroscopy is known for being a direct monitor of nonradiative de excitation processes, while photoconductivity spectroscopy is a direct monitor on the photocurrent generated following the absorption of the radiation source. If used simultaneously, they should unveil valuable information on the properties of materials. As an application to the refined spectrometer we present a comparative study on the optical absorption properties of CuInSe2 single. The measurements were performed at room temperature close to the absorption edge. Appropriate theoretical models have been used to evaluate the absorption coefficient spectral dependence from measured data. The combined techniques showed varying sensitivities in detecting defects levels in different regions of the absorption spectrum of the compound, and thus offering more information on the defects structure of semiconductors in a quicker way.", "author_names": [ "Fatima Zohra Satour", "Ameur Zegadi" ], "corpus_id": 213610285, "doc_id": "213610285", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "An optical absorption properties investigation of CuInSe2 by a simultaneous photoacoustic photoconductivity measuring technique", "venue": "", "year": 2020 }, { "abstract": "CuInSe 2 (CIS) and Cu(In,Ga)Se 2 (CIGS) semiconductors are the most studied absorber materials for thin films solar cells due to their direct bandgap and large absorption coefficient. The highly efficient CIGS devices are often fabricated using expensive vacuum based technologies; however, recently electrodeposition has been demonstrated to produce CIGS devices with high efficiencies and it is easily amenable for large area films of high quality with effective material use and high deposition rate. In this context, this chapter discusses the recent developments in CIS and CIGS technologies using electrodeposition. In addition, the fundamental features of electrodeposition such as direct current, pulse and pulse reverse plating and their application in the fabrication of CIS and CIGS films are discussed. In conclusion, the chapter summarizes the utilization of pulse electrodeposition for fabrication of CIS and CIGS films while making a recommendation for exploring the group's unique pulse electroplating method.", "author_names": [ "Sreekanth Mandati", "Bulusu V Sarada", "Suhash Ranjan Dey", "Shrikant V Joshi" ], "corpus_id": 55217856, "doc_id": "55217856", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Pulsed Electrochemical Deposition of CuInSe2 and Cu(In,Ga)Se2 Semiconductor Thin Films", "venue": "", "year": 2018 }, { "abstract": "CuInSe2 with chalcopyrite structure has become one of the most promising photoelectric materials for its high optical absorption coefficient and conversion efficiency. Electrodeposition has the advantages of low cost and easy operation. CuInSe2 thin films were prepared by one step electrodeposition with CuC12*2H2O, InC13, SeO2 as raw materials. Cyclic voltammetry curves of the solutions were tested by electrochemical workstation. The phases of product thin films were analyzed by X ray diffraction (XRD) and the surface morphology was characterized by scanning electron microscope (SEM) Experimental results show that the continuous, uniform and dense CuInSe2 thin films can be obtained under conditions of deposition potential 0.5 V and sodium citrate as complexing agent with concentration of 5mmol/L. The XRD diffraction peaks of CuInSe2 thin film are corresponding to the crystal planes of (112) (220) and (312) respectively.DOI: http:/dx.doi.org/10.5755/j01.ms.23.4.17447", "author_names": [ "Kegao Liu", "Chaoya Xu", "Hong Liu", "Yong Hu", "Lu Dan Shi" ], "corpus_id": 103006130, "doc_id": "103006130", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Phase and Morphology of CuInSe2 Film Prepared by One Step electrodeposition", "venue": "", "year": 2017 }, { "abstract": "ABSTRACT CuInSe2 as one I III VI ternary compound with direct band gap, has become one of the most promising photovoltaic materials due to high optical absorption coefficient and conversion efficiency. CuInSe2 films were prepared by electrodeposition with CuCl2*2H2O, InCl3, SeO2 as raw materials. The phases of product films were analyzed by X ray diffraction (XRD) and the morphology was characterized by scanning electron microscope (SEM) Experimental results show that dense and continuous CuInSe2 films can be obtained under conditions of deposition potential 0.5 V, pH 2.5 and raw materials ratio 6: 8: 12: 50, and the XRD diffraction peaks of CuInSe2 film are corresponding to (111) (220) and (311) crystal planes respectively, it consists of many rods with about 1 mm length; While the CuInSe2 film obtained under conditions of deposition potential 0.5 V, pH 2.0, and CuCl2*2H2O, InCl3, SeO2 and C6H5Na3O7*2H2O with concentrations of 6 mmol/L, 8 mmol/L, 6 mmol/L, 5 mmol/L respectively, shows different XRD diffraction peaks corresponding to (112) (220) and (312) crystal planes respectively, it consists of many non uniform particles with diameters about 0.5 1.5 mm distribute on the film surface with dense, continuous and unsmooth morphology.", "author_names": [ "Kegao Liu", "Hui Liu", "Jing Li", "Yong Xu" ], "corpus_id": 102133370, "doc_id": "102133370", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "The phases and morphology of CuInSe2 films prepared by different electrical deposition technologies", "venue": "", "year": 2016 }, { "abstract": "Monolayer MoS2, a direct bandgap transition metal dichalcogenide (TMD) has attracted worldwide attention in electronics and optoelectronics. However, the performance of photodetectors based on monolayer MoS2 is restricted to a weak optical absorption, narrow absorption range, and persistent photoconductance. Herein, benefiting from an easy solution process, high light absorption coefficient, and wide absorption range, environment friendly CuInSe2 quantum dots (QDs) are hybridized with monolayer MoS2 for high performance broadband photodetectors. Owing to the favorable type II energy band alignment of MoS2/CuInSe2 QDs, the hybrid photodetector exhibits a broadband photoresponse from the ultraviolet to near infrared region, with an ultrahigh photoresponsivity of 74.8 A/W at 1064 nm, and compared with those of the pristine MoS2 device, the photoresponsivity and specific detectivity in the ultraviolet visible region were enhanced by about 30 and 20 times, respectively. Furthermore, the formed depletion region at the MoS2/CuInSe2 QDs interface can significantly increase the photoresponse speed, and the accumulated holes in the QD side induce a strong photogating effect to improve the photoresponsive characteristics of the hybrid photodetector. Our work opens up opportunities for fabricating high performance monolayer TMD based broadband photodetectors.", "author_names": [ "Tao Shen", "Feng Li", "Zhenyun Zhang", "Lei Xu", "Junjie Qi" ], "corpus_id": 227175101, "doc_id": "227175101", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "High Performance Broadband Photodetector Based on Monolayer MoS2 Hybridized with Environment Friendly CuInSe2 Quantum Dots.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "Measurements of optical absorption coefficient (a) were made on Bridgman grown CuInSe2 samples, over the wavelength range 1300 to 1600 nm, at room temperature. The samples were obtained from multi crystalline ingots, grown from melts of composition CuInSe2+x, plus y atomic of elemental sodium. Here, x, the excess of Se over stoichiometry, ranged from 0 to 0.4 and y, the percentage of Na in the melt, ranged from 0 to 11 at It was found that a was considerably increased by the original Na in the melt and also by a stoichiometric deficiency of Se in the melt; that is with a melt formula corresponding to CuInSe1.8, (or x 0.2) A smaller increase of a was observed with increase of x, the Se excess. With the addition of Na2Se in the melt, little change was obtained compared with the large increase with elemental Na.", "author_names": [ "An Qi Jin", "Clifford H Champness", "Hadley Franklin Myers", "Ishiang Shih" ], "corpus_id": 43023234, "doc_id": "43023234", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optical absorption measurements in the wavelength range 1.3 1.6 microns in Bridgman CuInSe2 grown from melts with added sodium", "venue": "2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)", "year": 2013 }, { "abstract": "Global energy crisis is one of the major concerns of the humankind due to the limited availability of fossil fuels which accomplish dominant portion of present days\" energy. Hence, the need to develop renewable energy resources has come to the forefront of discussion. Solar photovoltaic is one of the major alternatives for future energy harvesting system; however, the utility of this emerging technology depends on the efficiency of the solar cell and viable techniques to commercialize it. Though silicon based photovoltaic technology is the most dominant till date but expensive manufacturing techniques pertaining to it is a major concern. In this context, chalcopyrite Cu(In,Ga)Se2 (CIGS) thin film technology has already witnessed high conversion efficiencies due to its suitable bandgap 1.20 eV) and large optical absorption coefficient 105 cm 1) The highly efficient CIGS devices are often fabricated using expensive vacuum based technologies; however, efforts to seek an economical and scalable method for the production of stoichiometric CIGS thinfilms have been ongoing to realize the commercialization of these devices. In pursuit of this, electrodeposition has been demonstrated to produce CIGS devices with high efficiencies and it is easily amenable for achieving large area films of high quality with efficient material utilization and high deposition rate. The use of multi steps, complexing agents, organic additives during the deposition using a three electrode system followed by a conventional selenization step have often been employed to achieve chalcopyrite compact CIGS which make the process more complex and expensive.", "author_names": [ "Sreekanth Mandati" ], "corpus_id": 138692268, "doc_id": "138692268", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Fabrication of CuInSe2 and Cu(In,Ga)Se2 Absorber Layersby Pulse and Pulse reverse Electrochemical Techniquesfor Solar Photovoltaic Applications", "venue": "", "year": 2015 }, { "abstract": "Highly ordered arrays of Cu rich and deficient CuInSe(2) nanotubes as well as ZnO/CuInSe(2) core/sheath nanocables have been synthesized on glass substrates by using ZnO nanorod arrays as sacrificial templates via a low cost solution method. Chemical conversions from hexagonal ZnO to cubic ZnSe, hexagonal CuSe and tetragonal CuInSe(2) are demonstrated as a novel means for synthesis of I III VI nanomaterials. Large differences in their solubility product constant (K(sp) are crucial for direct exchange in the conversions. In solvothermal reaction of ZnO/CuSe core/shell nanocables with InCl(3) the triethylene glycol solvent serves as a reducing agent for the reduction of cupric (Cu(2+ to cuprous (Cu( ions and also as an agent for the dissolution of ZnO cores. The absorption coefficient of the CuInSe(2) nanotubes in the visible region is on the order of 10(4) cm( 1) Photoelectrochemical solar cells were fabricated with arrays of ZnO/Cu(1.57+ 0.10)In(0.68+ 0.10)Se(2) and ZnO/CuSe nanocables. It was found that power conversion efficiency of the ZnO/Cu(1.57+ 0.10)In(0.68+ 0.10)Se(2) cell is about two times higher than that based on ZnO/CuSe.", "author_names": [ "Jun Xu", "Chunyan Luan", "Yong-Bing Tang", "Xue Chen", "Juan Antonio Zapien", "Wen-Jun Zhang", "H L Kwong", "Xiang-min Meng", "Shui-Tong Lee", "Chun-Sing Lee" ], "corpus_id": 27626888, "doc_id": "27626888", "n_citations": 84, "n_key_citations": 0, "score": 1, "title": "Low temperature synthesis of CuInSe2 nanotube array on conducting glass substrates for solar cell application.", "venue": "ACS nano", "year": 2010 }, { "abstract": "In this work, the electronic structure and dielectric function of chalcopyrite CuInSe2 are presented. The results are based on the full potential linearized augmented plane wave (FPLAPW) method using the generalized gradient approximation (GGA) plus an onsite Coulomb interaction U of the Cu d states. The dielectric constant, absorption coefficient and refractive index are explored by means of optical response. The spin orbit coupling effect is considered for the calculations of electronic structure and optical properties. We find that the results based on our calculation method have good agreement compared with experimental and other earlier simulations results.", "author_names": [ "Rong Chen", "Clas Persson" ], "corpus_id": 93164406, "doc_id": "93164406", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Band Structure and Optical Properties of CuInSe2", "venue": "", "year": 2014 }, { "abstract": "Abstract CuInSe2 (CISe) colloidal quantum dots (QDs) display promising applications in photodetection especially within near infrared (NIR) regions due to their high extinction coefficient and environmental friendly. However, the high trap density and poor crystal quality introduced by the ternary structure result in low photodetection of CISe QDs devices. Herein, we dope transition metal manganese ions (Mn2+ into CISe QDs to tackle the above problems. Structural characterization results demonstrate the crystal quality of CISe QDs is improved by doping Mn2+ during the synthesis of QDs. The transient absorption (TA) spectroscopic study together with the space charge limited current (SCLC) measurements show the charge carrier lifetime of Mn CISe QDs is much longer than that of the CISe QDs, due to the Mn2+ doping state serve as hole capturer forming a charge compensated pair with the Cu2+ defect that makes the long lived Cu2+ radiative recombination dominate. Furthermore, Mn2+ doping concurrently modifies the conduction band minimum and valence band maximum level of the QDs verified by the ultraviolet photoelectron spectroscopy (UPS) which determines the driving force for charge carrier transfer to acceptors. The optimal Mn2+ doping level (0.01 Mn:Cu feed ratio) balanced the above two factors in the QDs. The detector based on such Mn CISe QDs exhibits responsivity of 30 mA/W and specific detectivity of 4.2 x 1012 Jones at near infrared wavelength, the response speed of 0.76 us, and suppressed dark current density of 1.6 x 10 10 A cm 2.", "author_names": [ "Ruiqi Guo", "Jie Meng", "Weihua Lin", "Aqiang Liu", "Tonu Pullerits", "Kaibo Zheng", "Jianjun Tian" ], "corpus_id": 225011337, "doc_id": "225011337", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Manganese doped eco friendly CuInSe2 colloidal quantum dots for boosting near infrared photodetection performance", "venue": "", "year": 2021 } ]

[ { "abstract": "One of the important issues in the era of the Fourth Industrial Revolution is the commercialization of self driving technology. Also, core semiconductor technology and support capabilities are very important to continuously develop self driving technology. Along with looking at the status of the global semiconductor market, this paper's ultimate goal is to analyze the competitive edge of global innovative semiconductor companies' self driving solutions by dividing them into technology innovation, knowledge management, human resources, sustainable management, and commercial business factors. This paper finally provides milestones and counterplans of the Korean government, local car OEMs, and domestic semiconductor providers on future self driving solutions. For this paper's design and methodology, we extracted major factors for a competitive edge study using feedback and compelling data provided by experts and professors who have engaged in self driving solutions, as well as the automobile industry. Based on the finding of the study, the researchers found the comparative competitive edge level of global major semiconductor makers for each factor. This paper would also help the Korean government develop a strategy to cope with the self driving technology trend and global semiconductor market expansion.", "author_names": [ "Jae-Kyung Kim", "Jon-Mo Yoon", "Bong-Soo Lee" ], "corpus_id": 228933268, "doc_id": "228933268", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Assessment of Competitive Edge of Major Global Semiconductor Vendors for Self Driving Solutions (Level 3 and Above) Evaluation of Qualcomm, Intel, and Nvidia", "venue": "", "year": 2020 }, { "abstract": "In deep end to end learning based autonomous car design, inferencing the signal by trained model is one of the critical issues, particularly, in case of embedded component. Researchers from both academia and industry have been putting their enormous efforts in making this critical autonomous driving more reliable and safer. As research on the real car is costly and poses safety issue, we have developed a small scale, low cost, deep convolutional neural network powered self driving car model. Its learning model adopted from NVIDIA's DAVE 2 which is a real autonomous car and Kansas University's small scale DeepPicar. Similar to DAVE 2, its neural architecture uses 5 convolution layer and 3 fully connected layers with 250,000 parameters. We have considered Raspberry Pi 3B+ as the processing platform with Quad core 1.4 GHz CPU based on A53 architecture which is capable to support CNN learning model.", "author_names": [ "Arik Intisar", "Md Khaled Ben Islam", "Julia Rahman" ], "corpus_id": 213191647, "doc_id": "213191647", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Deep Convolutional Neural Network Based Small Scale Test bed for Autonomous Car", "venue": "ICCA", "year": 2020 }, { "abstract": "With the growing phase of artificial intelligence and autonomous learning, the self driving car is one of the promising area of research and emerging as a center of focus for automobile industries. Behavioral cloning is the process of replicating human behavior via visuomotor policies by means of machine learning algorithms. In recent years, several deep learning based behavioral cloning approaches have been developed in the context of self driving cars specifically based on the concept of transfer learning. Concerning the same, the present paper proposes a transfer learning approach using VGG16 architecture, which is fine tuned by retraining the last block while keeping other blocks as non trainable. The performance of proposed architecture is further compared with existing NVIDIA architecture and its pruned variants (pruned by 22.2% and 33.85% using 1x1 filter to decrease the total number of parameters) Experimental results show that the VGG16 with transfer learning architecture has outperformed other discussed approaches with faster convergence.", "author_names": [ "Uppala Sumanth", "Narinder Singh Punn", "Sanjay Kumar Sonbhadra", "Sonali Agarwal" ], "corpus_id": 220495979, "doc_id": "220495979", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Enhanced Behavioral Cloning Based self driving Car Using Transfer Learning", "venue": "ArXiv", "year": 2020 }, { "abstract": "The aviation industry has a market driven need to maintain and develop enhanced simulation capabilities for a wide range of application domains. In particular, the future growth and disruptive ability of smart cities, autonomous vehicles and in general, urban mobility, hinges on the development of state of the art simulation tools and the intelligent utilization of data. While aviation based companies have several historical and/or proprietary mission level simulation tools, there is much to learn from the current state of the art within other industries (tangential and competing in scope) as well as in academia. The purpose of this paper is to address and decompose the simulation capabilities within the key players of the autonomous vehicle and self driving car industry (Toyota, Waymo, BMW, Microsoft, NVIDIA, Uber, etc. as well as several notable startups within the high fidelity 3D mapping and simulation domain (this http URL, HERE, Cognata, etc. While providing an overview of how other companies are using simulation tools and reliable data sets, this paper will also seek to address several important and related questions, namely: the interaction between simulation and supporting tools/software, the intersection of simulation and the real world, the requirements and utilization of compute infrastructure, the appropriate levels of fidelity within simulation, and how simulation tools are critical to future safety and V&V concerns. In order for aviation based companies to adequately pursue disruptive mobility within real world environments, be it in air or on the ground, modeling and simulation tools for autonomous vehicles provide key insights into future development work and are essential technologies.", "author_names": [ "Joshua Fadaie" ], "corpus_id": 204509060, "doc_id": "204509060", "n_citations": 2, "n_key_citations": 1, "score": 1, "title": "The State of Modeling, Simulation, and Data Utilization within Industry: An Autonomous Vehicles Perspective", "venue": "ArXiv", "year": 2019 }, { "abstract": "In recent years, increases in computing power have reached the automotive industry in the form of advanced driver assistance systems (ADAS) Cars that support these systems require a variety of sensors and powerful computers. Sensor data must be processed and acted upon in real time so that the car can react to changes in its environment as they occur. This is especially important when the car must take action to avoid a collision and potentially prevent loss of life. GPUs offer a large speedup for processing sensor data but their runtime performance can be unpredictable in some cases. In this paper we evaluate the predictability of GPU programs on the NVIDIA Jetson TK1 and make them perform more predictably by using Zero Copy memory.", "author_names": [ "Vance Miller" ], "corpus_id": 196175346, "doc_id": "196175346", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Determinism in GPU Programs Real Time Applications on the NVIDIA Jetson TK1", "venue": "", "year": 2016 }, { "abstract": "The use of hand gestures can be the most intuitive human machine interaction medium. The early approaches for hand gesture recognition used device based methods. These methods use mechanical or optical sensors attached to a glove or markers, which hinders the natural human machine communication. On the other hand, vision based methods are not restrictive and allow for a more spontaneous communication without the need of an intermediary between human and machine. Therefore, vision gesture recognition has been a popular area of research for the past thirty years. Hand gesture recognition finds its application in many areas, particularly the automotive industry where advanced automotive human machine interface (HMI) designers are using gesture recognition to improve driver and vehicle safety. However, technology advances go beyond active/passive safety and into convenience and comfort. In this context, one of America's big three automakers has partnered with the Centre of Pattern Analysis and Machine Intelligence (CPAMI) at the University of Waterloo to investigate expanding their product segment through machine learning to provide an increased driver convenience and comfort with the particular application of hand gesture recognition for autonomous car parking. In this thesis, we leverage the state of the art deep learning and optimization techniques to develop a vision based multiview dynamic hand gesture recognizer for self parking system. We propose a 3DCNN gesture model architecture that we train on a publicly available hand gesture database. We apply transfer learning methods to fine tune the pre trained gesture model on a custom made data, which significantly improved the proposed system performance in real world environment. We adapt the architecture of the end to end solution to expand the state of the art video classifier from a single image as input (fed by monocular camera) to a multiview 360 feed, offered by a six cameras module. Finally, we optimize the proposed solution to work on a limited resources embedded platform (Nvidia Jetson TX2) that is used by automakers for vehicle based features, without sacrificing the accuracy robustness and real time functionality of the system.", "author_names": [ "Hassene Ben Amara" ], "corpus_id": 199586458, "doc_id": "199586458", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "End to End Multiview Gesture Recognition for Autonomous Car Parking System", "venue": "", "year": 2019 }, { "abstract": "Technology has become cheaper and more accessible, giving way to opportunities in technological areas that were previously inaccessible. Moreover, building a fully functional self driving vehicle has become the new gold rush in the current industries. Yet, there are many issues to solve when building an autonomous vehicle. For instance, a self driving vehicle must be reliable, consistent, predictable, and safe. There is still substantial amount of research and work that needs to be done, and more to learn, for the industry to build a truly reliable self driving vehicle. In this paper the basic concepts of self driving vehicles as well as some advanced concepts have been discussed. This project explores building a self driving car using an off the shelf remote controlled car, an NVIDIA Jetson TX2 GPU which has an ARM processor on board, infra red sensors for obstacle avoidance, and a monocular CSI camera for navigation and object detection. A combination of Google's TensorFlow, OpenCV and a Robot Operating System (ROS) enables the remote controlled car into becoming a fully self driving car.", "author_names": [ "Luis Bill", "Hamid Shahnasser" ], "corpus_id": 202699591, "doc_id": "202699591", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Development and Implementation of an Autonomously Driven Vehicle Prototype", "venue": "2019 IEEE 2nd International Conference on Electronics Technology (ICET)", "year": 2019 }, { "abstract": "Convolutional neural networks (CNN) have been proved to be an effective method in the field of artificial intelligence (AI) and large scale deploying CNN to embedded devices, no doubt, will greatly promote the development and application of AI into the practical industry. However, mainly due to the space time complexity of CNN, computing power, memory bandwidth and flexibility are performance bottlenecks. In this paper, a framework containing model compression and hardware acceleration is proposed to solve the above problems. This framework consists of a mixed pruning method, data storage optimization for efficient memory utilization and an accelerator for mapping CNN on field programmable gate array (FPGA) The mixed pruning method is used to compress the model, and data bit width is reduced to 8 bit by data quantization. Accelerator based on FPGA makes it flexible, configurable and efficient for CNN implementation. The model compression is evaluated on NVIDIA RTX2080Ti, and the results illustrate that the VGG16 is compressed by <inline formula> <tex math notation=\"LaTeX\"$30\\times /tex math>/inline formula> and the fully convolutional network (FCN) is compressed by <inline formula> <tex math notation=\"LaTeX\"$11\\times /tex math>/inline formula> within 1% accuracy loss. The compressed model is deployed and accelerated on ZCU102, which is up to <inline formula> <tex math notation=\"LaTeX\"$1.7\\times /tex math>/inline formula> and <inline formula> <tex math notation=\"LaTeX\"$24.5\\times /tex math>/inline formula> better in energy efficiency compared with RTX2080Ti and Intel i7 7700.", "author_names": [ "Xuepeng Chang", "Huihui Pan", "Weiyang Lin", "Huijun Gao" ], "corpus_id": 232153181, "doc_id": "232153181", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Mixed Pruning Based Framework for Embedded Convolutional Neural Network Acceleration", "venue": "IEEE Transactions on Circuits and Systems I: Regular Papers", "year": 2021 }, { "abstract": "The vision of autonomous vehicles on our roads is likely to become a reality in the near future. However, many challenges need to be explored and resolved before self driving cars are feasible. NetApp, a leading company in the storage industry, is working with NVIDIA, a leading AI computational company, to build the first industrial reference architecture for the automotive industry (Arnette Lin, 2020) This white paper introduces the reference architecture proposed by NetApp and NVIDIA and describes the challenges and concerns for building and validating this architecture. It also discusses performance considerations to help new AI teams and their IT colleagues accelerate their research, engineering workflows, and processes. In partnership with", "author_names": [ "Sung-Han Lin" ], "corpus_id": 218503285, "doc_id": "218503285", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Training Workflows for Faster Self Driving Results", "venue": "", "year": 2020 }, { "abstract": "Abstract To survive in an intensively competitive environment, semiconductor companies need to be more agile, responsive, and flexible than before. Generally, semiconductor industry consists of three business models: integrated design manufacturer, fabless chip design, and foundry business. In general, semiconductor firms are affected by three drivers: new entrants and rivals (competition) main customers (demand) and process technologies (R&D) Inspired by Michael Porter's five force analysis, a novel framework is presented to accomplish the following goals: (1) The interactions between the top three foundry firms, TSMC, Samsung, and Global Foundries, are analyzed to reveal managerial insights, (2) The main customers of TSMC including Apple, Huawei, Qualcomm, Mediatek, AMD, and NVidia are incorporated to into sales forecasting, and (3) Technological diffusion across the mature process (above 70 nm) the medium process (between 20 nm and 70 nm) and the advanced process (below 20 nm) is captured to predict sales revenues. Key findings are shown as follows: (1) a large scale foundry frim benefits from the existence of a small scale firm, (2) the inclusion of main customers significantly improves the performance of sales forecasting, (3) the advanced process gradually benefits from the mature process while it rapidly replaces the medium process in a \"predator prey\" way.", "author_names": [ "Chih-Hsuan Wang", "Hsuan-Chen Lin" ], "corpus_id": 233525695, "doc_id": "233525695", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Competitive substitution and technological diffusion for semiconductor foundry firms", "venue": "Adv. Eng. Informatics", "year": 2021 } ]

[ { "abstract": "Nine Switch Inverter (NSI) is a good alternative to two level three phase voltage source inverters (VSIs) when multiple loads exist in the system. Using multiple voltage source inverters is well known technique to drive multiple induction machines for multi drive systems. This increases total cost and volume of the system since more discrete components are required for designing the total system. On the other hand, Nine Switch Inverter provides promising solution to control multiple ac loads with less number of semiconductor switches. This converter has dual output and two ac loads can be controlled independently with no restriction. In this paper, model predictive control method is presented to control two induction machines using Nine Switch Inverter. The proposed method uses the mathematical model of the system to predict control objectives and solves multi objectives cost function to determine optimal control actuation. The performance of the predictive controller is evaluated by simulation work. According to simulation results, predictive controller provides good reference tracking capability in steady state and transient.", "author_names": [ "Ozan Gulbudak", "Mustafa Gokdag" ], "corpus_id": 46952110, "doc_id": "46952110", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Predictive dual induction machine control using nine switch inverter for multi drive systems", "venue": "2018 IEEE 12th International Conference on Compatibility, Power Electronics and Power Engineering (CPE POWERENG 2018)", "year": 2018 }, { "abstract": "Nowadays, multiphase induction drives are used in electric vehicle applications to improve reliability and efficiency. These induction motors are controlled by using a multiphase voltage source inverter (VSI) As the number of phases increases, the number of switching devices used in multiphase VSI also increases, which results in a reduction of the system efficiency and an increase in the cost. Among these multiphase drives, the six phase drive is used more frequently in electric vehicular industries. A conventional six phase VSI requires 12 switches to drive the six phase machine. Also, conventional six phase VSI requires more dc link voltage than the boost six phase VSI to drive the six phase machine. In order to overcome the problems associated with the conventional six phase VSI controlled six phase induction drives, this article proposes a nine switch boost inverter (NSBI) for six phase induction drive applications. The proposed NSBI has a single input dc voltage source, and it provides six phase ac output voltages. These six phase output voltages are regulated by using modified nonsinusoidal pulsewidth modulation (MNSPWM) technique. The proposed NSBI with a six phase induction motor is simulated using MATLAB/Simulink and validated using a field programmable gate array (FPGA) controlled hardware prototype. The verification of the proposed system during load torque variations and winding failure conditions is carried out.", "author_names": [ "Mohana Kishore Pinjala", "Ravikumar Bhimasingu" ], "corpus_id": 221846890, "doc_id": "221846890", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Improving the DC Link Utilization of Nine Switch Boost Inverter Suitable for Six Phase Induction Motor", "venue": "IEEE Transactions on Transportation Electrification", "year": 2020 }, { "abstract": "This paper presents the direct torque control (DTC) scheme for symmetrical six phase induction machine by using Nine Switch Inverter (NSI) When this motor is controlled by conventional two level inverter, it provides 64 voltage vectors with switch count of 12. The proposed inverter is nine switch two level having capability to produce 27 voltage vectors. The DTC control is implemented with these available voltage vectors by this inverter and flux of xy subspace is eliminated for the performance improvement. The torque ripple reduction is achieved by using five level torque comparator. The performance is presented through simulation results and confirmed through hardware implementation.", "author_names": [ "Sohit Sharma", "Mohan V Aware", "Apekshit Bhowate" ], "corpus_id": 13725473, "doc_id": "13725473", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Direct torque control of symmetrical six phase induction machine using nine switch inverter", "venue": "2017 IEEE Transportation Electrification Conference (ITEC India)", "year": 2017 }, { "abstract": "This paper investigates the performance of an asymmetrical six phase induction machine fed by a six phase nine switch voltage source inverter under both healthy and open motor phase cases. In the literature, the nine switch inverter topology is proposed as a suitable reduced switch count converter topology for six phase drives, where each pair of phases share the same converter leg. First, a brief summary about this topology along with its limitations are introduced. The six phase drive system topology is then investigated under both inverter and machine open circuit faults. Conventional rotor field oriented controller is employed as a controller platform for such a drive. Optimal current control is used under open phase conditions to ensure a certain optimization criterion, namely, minimum stator copper loss or maximum torque production. The system is investigated through a simulation study using MATLAB/SIMULINK.", "author_names": [ "Ahmed Salem", "Ragi A R Hamdy", "Ayman Samy Abdel-Khalik", "Ibrahim F El-Arabawy", "Mostafa S Hamad" ], "corpus_id": 41115409, "doc_id": "41115409", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Performance of nine switch inverter fed asymmetrical six phase induction machine under machine and converter faults", "venue": "2016 Eighteenth International Middle East Power Systems Conference (MEPCON)", "year": 2016 }, { "abstract": "This paper introduces a new transformerless converter topology for Multiphase Based Wind Energy Conversion Systems (WECSs) In this topology, a twelve phase induction generator is integrated to the grid using dual Nine Switch Converters (NSCs) connected in series forming a high voltage cascaded dc link. For this generator phase number, this topology reduces the total number of semiconductor devices in the machine side converter by 25% than conventional topologies, where four three phase two level voltage source converters are typically needed. Moreover, it offers a high ac dc boosting capability, which facilities a transformerless system operation. The twelve phase induction generator can be regarded as dual symmetrical six phase windings with a spatial displacement of 30deg. Therefore, each NSC controls each six phase winding set. The dc link midpoint balancing is achieved based on controlling the (x y) current components of the two winding groups. The proposed topology and its control system are analyzed and simulated under different operating cases using MATLAB/SIMULINK.", "author_names": [ "Sherif M Dabour", "Ayman Samy Abdel-Khalik", "Shehab Ahmed", "Ahmed M Massoud" ], "corpus_id": 35784740, "doc_id": "35784740", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "A new dual series connected Nine Switch Converter topology for a twelve phase induction machine wind energy system", "venue": "2017 11th IEEE International Conference on Compatibility, Power Electronics and Power Engineering (CPE POWERENG)", "year": 2017 }, { "abstract": "This paper describes a model predictive control method for Nine Switch Inverter (NSI) based AC drive systems. Two separate three phase AC loads (dual output mode operation) or a single six phase load (six phase mode operation) can be connected to output terminals of an NSI. Three different Finite Control Set Model Predictive Control (FCS MPC) strategies are presented and described. Firstly, dual output mode FCS MPC provides flexible control of detached load stages without any undesirable interaction. When disseminated loads are needed to be controlled, the output terminals of NSI are individually connected to separate load stages. Secondly, six phase mode FCS MPC provides robust control of six phase load current. Thirdly, the predictive control scheme for controlling multiple induction machines is presented. Experimental and simulation tests have demonstrated that the proposed method exhibits a secured converter operation. The proposed predictive control strategies of Nine Switch Inverter are accomplished using a Field Programmable Gate Arrays (FPGA)", "author_names": [ "Ozan Gulbudak", "Mustafa Gokdag" ], "corpus_id": 225057668, "doc_id": "225057668", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Finite control set model predictive control approach of nine switch inverter based drive systems: Design, analysis, and validation.", "venue": "ISA transactions", "year": 2020 }, { "abstract": "Modern ship propulsion systems are looking towards to high efficiency electric drive systems. This work presents a new inverter configuration for multiphase AC drives for its application in Full Electric Ship (FEP) propulsion. Simulation results based on real hull dynamic data where carried out different load impacts and speed reversion in normal and stator winding faulty conditions.", "author_names": [ "Carlos A Reusser" ], "corpus_id": 37014179, "doc_id": "37014179", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Full electric ship propulsion, based on a dual nine switch inverter topology for dual three phase induction motor drive", "venue": "2016 IEEE Transportation Electrification Conference and Expo (ITEC)", "year": 2016 }, { "abstract": "Induction motors are still popular in industries amongst the several types of motor due to its simple, robust and maintenance free construction. With the fast progress in transport industry the need exists for ac machines with higher power per unit. Six phase induction motor is a solution where higher power per volume is required such as for electric vehicle application. In this paper, six phase induction motor is operated by compact nine switch inverter. Space vector modulation technique is incorporated to operate nine switch inverter for six phase induction motor drive.", "author_names": [ "Chaitanya N Jibhakate", "Madhuri A Chaudhari", "Mohan M Renge" ], "corpus_id": 219121866, "doc_id": "219121866", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Space Vector Modulation of Nine Switch Inverter for Six Phase Induction Motor Drive", "venue": "", "year": 2020 }, { "abstract": "The Nine Switch Inverter (NSI) is a recently developed dual output converter. It can be used to drive two three phase loads independently. As a substitute to two separate conventional voltage source inverters, the NSI has been, already, proposed in various industrial applications to reduce the number of semiconductor switches and its associated energy losses and drive circuitry. On the other hand, the Direct Torque Control (DTC) is a robust control scheme of AC motors, which consist of selecting proper state vectors of a conventional voltage source inverter. The NSI, having a different working principle from the conventional voltage source inverter and taking into account the varying influence of active space vectors on motor's torque and stator flux, a Direct Torque Control is suggested in this paper to, efficiently, drive two induction motors independently, while minimizing the torque and stator flux ripples of both motors. Simulations results confirm the effectiveness of the proposed algorithm. In addition, application of this newly proposed control scheme in operation of an Electric Vehicule (EV) is demonstrated.", "author_names": [ "Draoui Abdelghani", "Allaoua Boumediene" ], "corpus_id": 53536075, "doc_id": "53536075", "n_citations": 8, "n_key_citations": 2, "score": 0, "title": "Direct Torque Control of Two Induction Motors Using the Nine Switch Inverter", "venue": "", "year": 2018 }, { "abstract": "Nine Switch Inverter (NSI) is composed of two conventional inverters with three common switches. Two sets of three phase ac loads can be connected to the outputs of NSI and independently controlled without any undesirable interaction. In conventional multi step Model Predictive Control (MPC) of a nine switch inverter, the prediction steps of both load stages must be equal. Unfortunately, this results in losing the freedom of selecting independent prediction horizon for individual loads. To overcome this problem, a novel asymmetrical multi step direct model predictive control method is presented in this paper. The proposed method finds two independent optimum solutions for each load to match with their utilization profile. It is assumed that two individual loads are controlled by two separate virtual inverters, and two separate model predictive control problems with their own prediction steps are solved to identify optimum control actions. The control calculations are performed in a Cyclone IV Field Programmable Gate Array (FPGA) by using a pipelined architecture. The system stability is analyzed using Lyapunov stability method. To highlight the effectiveness of introduced strategy, mathematical proof for controlling two separate loads with an asymmetrical prediction step is validated in experimentally.", "author_names": [ "Ozan Gulbudak", "Mustafa Gokdag" ], "corpus_id": 208207678, "doc_id": "208207678", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Asymmetrical Multi Step Direct Model Predictive Control of Nine Switch Inverter for Dual Output Mode Operation", "venue": "IEEE Access", "year": 2019 } ]

[ { "abstract": "Depth information is important for autonomous systems to perceive environments and estimate their own state. Traditional depth estimation methods, like structure from motion and stereo vision matching, are built on feature correspondences of multiple viewpoints. Meanwhile, the predicted depth maps are sparse. Inferring depth information from a single image (monocular depth estimation) is an ill posed problem. With the rapid development of deep neural networks, monocular depth estimation based on deep learning has been widely studied recently and achieved promising performance in accuracy. Meanwhile, dense depth maps are estimated from single images by deep neural networks in an end to end manner. In order to improve the accuracy of depth estimation, different kinds of network frameworks, loss functions and training strategies are proposed subsequently. Therefore, we survey the current monocular depth estimation methods based on deep learning in this review. Initially, we conclude several widely used datasets and evaluation indicators in deep learning based depth estimation. Furthermore, we review some representative existing methods according to different training manners: supervised, unsupervised and semi supervised. Finally, we discuss the challenges and provide some ideas for future researches in monocular depth estimation.", "author_names": [ "Chaoqiang Zhao", "Qiyu Sun", "Chongzhen Zhang", "Yang Tang", "Feng Qian" ], "corpus_id": 212725052, "doc_id": "212725052", "n_citations": 29, "n_key_citations": 3, "score": 0, "title": "Monocular depth estimation based on deep learning: An overview", "venue": "Science China Technological Sciences", "year": 2020 }, { "abstract": "Monocular depth estimation from Red Green Blue (RGB) images is a well studied ill posed problem in computer vision which has been investigated intensively over the past decade using Deep Learning (DL) approaches. The recent approaches for monocular depth estimation mostly rely on Convolutional Neural Networks (CNN) Estimating depth from two dimensional images plays an important role in various applications including scene reconstruction, 3D object detection, robotics and autonomous driving. This survey provides a comprehensive overview of this research topic including the problem representation and a short description of traditional methods for depth estimation. Relevant datasets and 13 state of the art deep learning based approaches for monocular depth estimation are reviewed, evaluated and discussed. We conclude this paper with a perspective towards future research work requiring further investigation in monocular depth estimation challenges.", "author_names": [ "Faisal Khan", "Saqib Salahuddin", "Hossein Javidnia" ], "corpus_id": 216073553, "doc_id": "216073553", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Deep Learning Based Monocular Depth Estimation Methods A State of the Art Review", "venue": "Sensors", "year": 2020 }, { "abstract": "Estimating depth from RGB images is a long standing ill posed problem, which has been explored for decades by the computer vision, graphics, and machine learning communities. Among the existing techniques, stereo matching remains one of the most widely used in the literature due to its strong connection to the human binocular system. Traditionally, stereo based depth estimation has been addressed through matching hand crafted features across multiple images. Despite the extensive amount of research, these traditional techniques still suffer in the presence of highly textured areas, large uniform regions, and occlusions. Motivated by their growing success in solving various 2D and 3D vision problems, deep learning for stereo based depth estimation has attracted growing interest from the community, with more than 150 papers published in this area between 2014 and 2019. This new generation of methods has demonstrated a significant leap in performance, enabling applications such as autonomous driving and augmented reality. In this article, we provide a comprehensive survey of this new and continuously growing field of research, summarize the commonly used pipelines, and discuss their benefits and limitations. In retrospect of what has been achieved so far, we conjecture what the future may hold for deep learning based stereo for depth estimation research.", "author_names": [ "Hamid Laga", "Laurent Valentin Jospin", "Farid Boussaid", "Mohammed Bennamoun" ], "corpus_id": 219303641, "doc_id": "219303641", "n_citations": 10, "n_key_citations": 1, "score": 0, "title": "A Survey on Deep Learning Techniques for Stereo based Depth Estimation", "venue": "IEEE transactions on pattern analysis and machine intelligence", "year": 2020 }, { "abstract": "Abstract In a single bevel GMAW (gas metal arc welding) with gap fluctuation, a deep learning model was constructed using the monitoring image during the welding to predict the welding quality. We utilized Python and the library Keras and created a CNN (Convolutional neural network) model using the top surface image including the molten pool as an input. The classification model was used to predict the burn through, and the regression model was used to estimate the penetration depth. As a result, the excessive penetration and burn through could be predicted in advance and more than 95 of estimated results of penetration depth were less 1 mm error for stepped and tapered sample shapes.", "author_names": [ "Kazufumi Nomura", "Koki Fukushima", "Takumi Matsumura", "Satoru Asai" ], "corpus_id": 228896242, "doc_id": "228896242", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Burn through prediction and weld depth estimation by deep learning model monitoring the molten pool in gas metal arc welding with gap fluctuation", "venue": "", "year": 2020 }, { "abstract": "We introduce SUW Learn: A framework for deep learning with joint supervised learning (S) unsupervised learning (U) and weakly supervised learning (W) We deploy SUWLearn for deep learning of the monocular depth from images and video sequences. The supervised learning module optimizes a depth estimation network by knowledge of the ground truth depth. In contrast, the unsupervised learning module has no knowledge of the ground truth depth, but optimizes the depth estimation network by predicting the current frame from the estimated 3D geometry. The weakly supervised module optimizes the depth estimation by evaluating the consistency between the estimated depth and weak labels derived from other information, such as the semantic information. SUW Learn trains the deep learning networks end to end with joint optimization of the desired SUW objectives. We benchmark SUW Learn on the commonly used KITTI driving scene and achieve the state of the art performance. To demonstrate the capacity of SUW Learn in learning the depth of scenes with people from different sources with different domain knowledge, we construct the M&M dataset from the Megadepth and Mannequin Challenge datasets.", "author_names": [ "Haoyu Ren", "Aman Raj", "Mostafa El-Khamy", "Jungwon Lee" ], "corpus_id": 220247854, "doc_id": "220247854", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "SUW Learn: Joint Supervised, Unsupervised, Weakly Supervised Deep Learning for Monocular Depth Estimation", "venue": "2020 IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW)", "year": 2020 }, { "abstract": "Abstract. Depth is an essential component for various scene understanding tasks and for reconstructing the 3D geometry of the scene. Estimating depth from stereo images requires multiple views of the same scene to be captured which is often not possible when exploring new environments with a UAV. To overcome this monocular depth estimation has been a topic of interest with the recent advancements in computer vision and deep learning techniques. This research has been widely focused on indoor scenes or outdoor scenes captured at ground level. Single image depth estimation from aerial images has been limited due to additional complexities arising from increased camera distance, wider area coverage with lots of occlusions. A new aerial image dataset is prepared specifically for this purpose combining Unmanned Aerial Vehicles (UAV) images covering different regions, features and point of views. The single image depth estimation is based on image reconstruction techniques which uses stereo images for learning to estimate depth from single images. Among the various available models for ground level single image depth estimation, two models, 1) a Convolutional Neural Network (CNN) and 2) a Generative Adversarial model (GAN) are used to learn depth from aerial images from UAVs. These models generate pixel wise disparity images which could be converted into depth information. The generated disparity maps from these models are evaluated for its internal quality using various error metrics. The results show higher disparity ranges with smoother images generated by CNN model and sharper images with lesser disparity range generated by GAN model. The produced disparity images are converted to depth information and compared with point clouds obtained using Pix4D. It is found that the CNN model performs better than GAN and produces depth similar to that of Pix4D. This comparison helps in streamlining the efforts to produce depth from a single aerial image.", "author_names": [ "L Madhuanand", "Francesco Nex", "M Ying Yang" ], "corpus_id": 222120245, "doc_id": "222120245", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "DEEP LEARNING FOR MONOCULAR DEPTH ESTIMATION FROM UAV IMAGES", "venue": "", "year": 2020 }, { "abstract": "Monocular depth estimation relied on RGB images is an important ill posed problem in ithe system of computer vision. Recently, people use the method of deep learning to discuss this problem Most of the existing monocular depth estimation algorithms relied on convolution neural network. Depth estimation based on 2D images has important applications in image segmentation, 3D object detection, robot navigation, object tracking and autonomous driving. This paper gives a brief overview of this problem, reviews, evaluates and discusses the monocular depth estimation algorithms relied on deep learning, and looks forward to the direction of further research in the face of some challenges.", "author_names": [ "Ruan Xiaogang", "Yan Wenjing", "Huang Jing", "Guo Peiyuan", "Guo-Qing Wei" ], "corpus_id": 231737219, "doc_id": "231737219", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Monocular Depth Estimation Based on Deep Learning:A Survey", "venue": "2020 Chinese Automation Congress (CAC)", "year": 2020 }, { "abstract": "Offset Pixel Aperture (OPA) camera has been recently proposed to estimate disparity of a scene with a single shot. Disparity is obtained in the image by offsetting the pixels by a fixed distance. Previously, correspondence matching schemes have been used for disparity estimation with OPA. To improve disparity estimation we use a data oriented approach. Specifically, we use unsupervised deep learning to estimate the disparity in OPA images. We propose a simple modification to the training strategy which solves the vanishing gradients problem with the very small baseline of the OPA camera. Training degenerates to poor disparity maps if the OPA images are used directly for left right consistency check. By using images obtained from displaced cameras at training, accurate disparity maps are obtained. The performance of the OPA camera is significantly improved compared to previously proposed single shot cameras and unsupervised disparity estimation methods. The approach provides 8 frames per second on a single Nvidia 1080 GPU with 1024x512 OPA images. Unlike conventional approaches, which are evaluated in controlled environments, our paper shows the utility of deep learning for disparity estimation with real life sensors and low quality images. By combining OPA with deep learning, we obtain a small depth sensor capable of providing accurate disparity at usable frame rates. Also the ideas in this work can be used in small baseline stereo systems for short range depth estimation and multi baseline stereo to increase the depth range.", "author_names": [ "Saad Ali Imran", "Sikander Bin Mukarram", "Muhammad Umar Karim Khan", "C M Kyung" ], "corpus_id": 213004912, "doc_id": "213004912", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Unsupervised deep learning for depth estimation with offset pixels.", "venue": "Optics express", "year": 2020 }, { "abstract": "Light field imaging is one of the most promising methods to capture realistic 3D scenes. In this paper, we propose a deep learning network composed of two sub networks performing depth estimation and light field image reconstruction, respectively. We simultaneously train the two sub networks by employing a loss function combining the reconstruction loss of the reconstruction network and the estimation loss of the depth estimation network. Experimental results demonstrate that the proposed method accurately estimates the disparity maps of light field images and also faithfully reconstructs light field images.", "author_names": [ "Jae-Seong Yun", "Jae-Young Sim" ], "corpus_id": 231850996, "doc_id": "231850996", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Deep Learning Based Depth Estimation and Reconstruction of Light Field Images", "venue": "2020 Asia Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA ASC)", "year": 2020 }, { "abstract": "Image depth estimation is an important technology for obtaining scene depth for 3D images, and it has developed rapidly in the field of computer vision. In this paper, convolutional neural networks and conditional random fields are unified into a deep learning framework to build a computer vision model. First, based on the architecture of multiscale CNN and CRF, information of the scene image is obtained from computer video using depth learning, and then, a new frame model is built to predict the depth of images in a computer video. Second, three international standard datasets are used for training, and the results show that the CNN CRF model can use a small number of samples to complete high precision training and has a better estimation effect on images outside the dataset. The experimental results show that the CNN CRF model can recover the depth and speculate the 3D structure of the scene, which has predictable application and development value for improving production efficiency.", "author_names": [ "Runchu Xu" ], "corpus_id": 211073854, "doc_id": "211073854", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Depth Estimation of Computer Video Images Based on Deep Learning", "venue": "Circuits Syst. Signal Process.", "year": 2020 } ]

[ { "abstract": "As an emerging two dimensional (2D) semiconductor, monolayer antimonene think graphene, but made of Sb instead of C, and not so flat is of great potential for (opto)electronic devices. High quality electrode contact is critical to developing these devices. In this article, calculations of electronic structure and quantum transport are used to study the interfacial properties of antimonene metal contacts. This comprehensive investigation provides a theoretical basis for selecting favorable electrodes in 2D antimonene devices. The optimal $n$ type electrode is 2D Hf$}_{2}$N(OH)}_{2} while the optimal $p$ type electrode is graphene Pt, both of which provide Ohmic contact.", "author_names": [ "Han Zhang", "Junhua Xiong", "Meng Ye", "Jingzhen Li", "Xiuying Zhang", "Ruge Quhe", "Zhigang Song", "Jinbo Yang", "Qiaoxuan Zhang", "Bowen Shi", "Jiahuan Yan", "Wanlin Guo", "John Robertson", "Feng Pan", "Jing Lu" ], "corpus_id": 195488546, "doc_id": "195488546", "n_citations": 11, "n_key_citations": 0, "score": 1, "title": "Interfacial Properties of Monolayer Antimonene Devices", "venue": "Physical Review Applied", "year": 2019 }, { "abstract": "Monolayer antimonene is fabricated on PdTe2 by an epitaxial method. Monolayer antimonene is theoretically predicted to have a large bandgap for nanoelectronic devices. Air exposure experiments indicate amazing chemical stability, which is great for device fabrication. A method to fabricate high quality monolayer antimonene with several great properties for novel electronic and optoelectronic applications is provided.", "author_names": [ "Xu Wu", "Yan Shao", "Hang Liu", "Zili Feng", "Ye-Liang Wang", "Jia-Tao Sun", "Chen Liu", "Jiaou Wang", "Zhu Liu", "Shiyu Zhu", "Yu-qi Wang", "Shixuan Du", "You-Guo Shi", "Kurash Ibrahim", "Hongjun Gao" ], "corpus_id": 5668438, "doc_id": "5668438", "n_citations": 217, "n_key_citations": 1, "score": 0, "title": "Epitaxial Growth and Air Stability of Monolayer Antimonene on PdTe2.", "venue": "Advanced materials", "year": 2017 }, { "abstract": "Antimonene based 2D materials are attracting increasing research interest due to their superior physicochemical properties and promising applications in next generation electronics and optoelectronics devices. However, the semiconductor properties of antimonene are still at the theoretical simulation stage and are not experimentally verified, significantly restricting its applications in specific areas. In this study, the semiconductor properties of monolayer antimonene nanosheets are experimentally verified. It is found that the obtained semiconductive antimonene nanosheets (SANs) exhibit indirect bandgap properties, with photoluminescence (PL) bandgap at about 2.33 eV and PL lifetime of 4.3 ns. Moreover, the obtained SANs are ideal for the hole extraction layer in planar inverted perovskite solar cells (PVSCs) and significantly enhance the device performance due to fast hole extraction and efficient hole transfer at the perovskite/hole transport layer interface. Overall, these findings look promising for the future prospects of antimonene in electronics and optoelectronics.", "author_names": [ "Fan Zhang", "Junjie He", "Yuren Xiang", "Kai Zheng", "Bin Xue", "Shuai Ye", "Xiao Peng", "Yuying Hao", "Jiarong Lian", "Pengju Zeng", "Junle Qu", "Jun Song" ], "corpus_id": 205288399, "doc_id": "205288399", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Semimetal Semiconductor Transitions for Monolayer Antimonene Nanosheets and Their Application in Perovskite Solar Cells.", "venue": "Advanced materials", "year": 2018 }, { "abstract": "Group V elemental monolayers were recently predicted to exhibit exotic physical properties such as nontrivial topological properties, or a quantum anomalous Hall effect, which would make them very suitable for applications in next generation electronic devices. The free standing group V monolayer materials usually have a buckled honeycomb form, in contrast with the flat graphene monolayer. Here, we report epitaxial growth of atomically thin flat honeycomb monolayer of group V element antimony on a Ag(111) substrate. Combined study of experiments and theoretical calculations verify the formation of a uniform and single crystalline antimonene monolayer without atomic wrinkles, as a new honeycomb analogue of graphene monolayer. Directional bonding between adjacent Sb atoms and weak antimonene substrate interaction are confirmed. The realization and investigation of flat antimonene honeycombs extends the scope of two dimensional atomically thick structures and provides a promising way to tune topological properties for future technological applications.", "author_names": [ "Jiaou Wang", "Kurash Ibrahim", "Jia-Tao Sun", "Ye-Liang Wang" ], "corpus_id": 206746909, "doc_id": "206746909", "n_citations": 130, "n_key_citations": 1, "score": 0, "title": "Epitaxial Growth of Flat Antimonene Monolayer: A New Honeycomb Analogue of Graphene.", "venue": "Nano letters", "year": 2018 }, { "abstract": "The integration of two dimensional (2D) materials with III V semiconductor surfaces leads to the formation of 2D/3D van der Waals (vdW) heterostructures without the constraint of lattice matching, which offers new opportunities to improve electronic and optoelectronic properties. Here we explore the structural, electronic, and optical properties of various potential Sb/GaAs heterostructures consisting of a Sb monolayer (i.e. antimonene) on GaAs(111) substrates by using first principles calculations within the density functional theory. Our results demonstrate that the vdW interaction is crucial for the stability of Sb/GaAs heterointerfaces, but the interfacial coupling strength and band structure characteristics of the heterostructures are strongly affected by the interface structures. We find that all stable Sb/GaAs heterostructures exhibit a type II band alignment and have relatively small band gaps (0.71 1.39 eV) as compared to those of the independent Sb monolayer and GaAs substrates. Moreover, the formation of Sb/GaAs vdW heterostructures can lead to the separation of carriers and a high optical absorption coefficient in the visible light range, which makes Sb/GaAs heterostructures a potential candidate for optoelectronic devices, such as solar cells.", "author_names": [ "Ning Wang", "Dan Cao", "Jun Wang", "Pei Liang", "Xiaoshuang Chen", "Haibo Shu" ], "corpus_id": 140020789, "doc_id": "140020789", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Interface effect on electronic and optical properties of antimonene/GaAs van der Waals heterostructures", "venue": "", "year": 2017 }, { "abstract": "Recently, arsenene monolayer structure of the arsenic with two phases has displayed semiconducting behavior. We have systematically investigated the electronic and optical properties of single layer arsenene with two types of functionalized organic molecules; an electrophilic molecule [tetracyanoquinodimethane (TCNQ) and a nucleophilic molecule [tetrathiafulvalene (TTF) as an electron acceptor and electron donor, respectively. The interfacial charge transfer between the arsenene monolayer and TCNQ/TTF molecules extensively reduces the band gap of arsenene and accordingly resulted in a p or n type semiconducting behavior, respectively. We have also performed the interfacial charge transfer from organic molecules to monolayer arsenene and vice versa. The interfacial surface molecular modification has established an efficient way to develop the light harvesting of arsenene in different polarization directions. Our theoretical investigation suggests that such n and p type arsenene semiconductors would broaden the applications in the field of nanoelectronic and optoelectronic devices such as photodiodes and it is also useful for constructing functional electronic systems.", "author_names": [ "Deobrat Singh", "Sanjeev K Gupta", "Yogesh Sonvane", "Satyaprakash Sahoo" ], "corpus_id": 38575200, "doc_id": "38575200", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Modulating the electronic and optical properties of monolayer arsenene phases by organic molecular doping.", "venue": "Nanotechnology", "year": 2017 }, { "abstract": "The interfacial properties of b12 phase borophene contacts with other common two dimensional materials (transition metal dichalcogenides, group IV enes and group V enes) have been systematically studied using a density functional theory (DFT) method. The zero tunneling barrier is found for all of the investigated b12 phase borophene contacts except for the case of b12 borophene/graphene. The chemically reactive properties and high work function (4.9 eV) of the stable b12 borophene lead to the formation of Ohmic contacts with silicene, germanene, stanene, black phosphorene, arsenene and antimonene. The advantage of the zero tunnel barrier remains when changing the borophene from the b12 phase to the D phase. Therefore, a high carrier injection rate is expected in these borophene contacts. Our study provides guidance on borophene for future two dimensional materials based device designs.", "author_names": [ "Jie Yang", "Ruge Quhe", "Shenyan Feng", "Qiaoxuan Zhang", "Minglong Lei", "Jing Lu" ], "corpus_id": 46847753, "doc_id": "46847753", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Interfacial properties of borophene contacts with two dimensional semiconductors.", "venue": "Physical chemistry chemical physics PCCP", "year": 2017 }, { "abstract": "Arsenene, arsenic analogue of graphene, as an emerging member of two dimensional semiconductors (2DSCs) is quite promising in next generation electronic and optoelectronic applications. The metal electrical contacts play a vital role in the charge transport and photoresponse processes of nanoscale 2DSC devices and even can mask the intrinsic properties of 2DSCs. Here, we present a first comprehensive study of the electrical contact properties of monolayer (ML) arsenene with different electrodes by using ab initio electronic calculations and quantum transport simulations. Schottky barrier is always formed with bulk metal contacts owing to the Fermi level pinning (pinning factor S 0.33) with electron Schottky barrier height (SBH) of 0.12, 0.21, 0.25, 0.35, and 0.50 eV for Sc, Ti, Ag, Cu, and Au contacts and hole SBH of 0.75 and 0.78 eV for Pd and Pt contacts, respectively. However, by contact with 2D graphene, the Fermi level pinning effect can be reduced due to the suppression of metal induced gap states. Remarkably, a barrier free hole injection is realized in ML arsenene device with graphene Pt hybrid electrode, suggestive of a high device performance in such a ML arsenene device. Our study provides a theoretical foundation for the selection of favorable electrodes in future ML arsenene devices.", "author_names": [ "Meng Ye", "Mouyi Weng", "Jingzhen Li", "Xiuying Zhang", "Han Zhang", "Ying Guo", "Yuanyuan Pan", "Linhong Xiao", "Junku Liu", "Feng Pan", "Jing Lu" ], "corpus_id": 206460315, "doc_id": "206460315", "n_citations": 62, "n_key_citations": 0, "score": 0, "title": "Electrical Contacts in Monolayer Arsenene Devices.", "venue": "ACS applied materials interfaces", "year": 2017 }, { "abstract": "Two dimensional (2D) layered materials hold great promise for various future electronic and optoelectronic devices that traditional semiconductors cannot afford. 2D pnictogen, group VA atomic sheet (including phosphorene, arsenene, antimonene, and bismuthene) is believed to be a competitive candidate for next generation logic devices. This is due to their intriguing physical and chemical properties, such as tunable midrange bandgap and controllable stability. Since the first black phosphorus field effect transistor (FET) demo in 2014, there has been abundant exciting research advancement on the fundamental properties, preparation methods, and related electronic applications of 2D pnictogen. Herein, we review the recent progress in both material and device aspects of 2D pnictogen FETs. This includes a brief survey on the crystal structure, electronic properties and synthesis, or growth experiments. With more device orientation, this review emphasizes experimental fabrication, performance enhancing approaches, and configuration engineering of 2D pnictogen FETs. At the end, this review outlines current challenges and prospects for 2D pnictogen FETs as a potential platform for novel nanoelectronics.", "author_names": [ "Wenhan Zhou", "Jiayi Chen", "Pengxiang Bai", "Shiying Guo", "Shengli Zhang", "Xiufeng Song", "Lijuan Tao", "Haibo Zeng" ], "corpus_id": 208162944, "doc_id": "208162944", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Two Dimensional Pnictogen for Field Effect Transistors", "venue": "Research", "year": 2019 }, { "abstract": "The growth and exfoliation of two dimensional (2D) materials have led to the creation of edges and novel interfacial states at the juncture between crystals with different composition or phases. These hybrid heterostructures (HSs) can be built as vertical van der Waals stacks, resulting in a 2D interface, or as stitched adjacent monolayer crystals, resulting in one dimensional (1D) interfaces. Although most attention has been focused on vertical HSs, increasing theoretical and experimental interest in 1D interfaces is evident. In plane interfacial states between different 2D materials inherit properties from both crystals, giving rise to robust states with unique 1D non parabolic dispersion and strong spin orbit effects. With such unique characteristics, these states provide an exciting platform for realizing 1D physics. Here, we review and discuss advances in 1D heterojunctions, with emphasis on theoretical approaches for describing those between semiconducting transition metal dichalcogenides MX 2 (with M Mo, W and X S, Se, Te) and how the interfacial states can be characterized and utilized. We also address how the interfaces depend on edge geometries (such as zigzag and armchair) or strain, as lattice parameters differ across the interface, and how these features affect excitonic/optical response. This review is intended to serve as a resource for promoting theoretical and experimental studies in this rapidly evolving field.", "author_names": [ "Oscar Avalos-Ovando", "Diego Mastrogiuseppe", "Sergio E Ulloa" ], "corpus_id": 73507382, "doc_id": "73507382", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Lateral heterostructures and one dimensional interfaces in 2D transition metal dichalcogenides.", "venue": "Journal of physics. Condensed matter an Institute of Physics journal", "year": 2019 } ]

[ { "abstract": "VOLUME ONE: Determination of Optical Constants: E.D. Palik, Introductory Remarks. R.F. Potter, Basic Parameters for Measuring Optical Properties. D.Y. Smith, Dispersion Theory, Sum Rules, and Their Application to the Analysis of Optical Data. W.R. Hunter, Measurement of Optical Constants in the Vacuum Ultraviolet Spectral Region. D.E. Aspnes, The Accurate Determination of Optical Properties by Ellipsometry. J. Shamir, Interferometric Methods for the Determination of Thin Film Parameters. P.A. Temple, Thin Film Absorplance Measurements Using Laser Colorimetry. G.J. Simonis, Complex Index of Refraction Measurements of Near Millimeter Wavelengths. B. Jensen, The Quantum Extension of the Drude Zener Theory in Polar Semiconductors. D.W. Lynch, Interband Absorption Mechanisms and Interpretation. S.S. Mitra, Optical Properties of Nonmetallic Solids for Photon Energies below the Fundamental Band Gap. Critiques Metals: D.W. Lynch and W.R. Hunter, Comments of the Optical Constants of Metals and an Introduction to the Data for Several Metals. D.Y. Smith, E. Shiles, and M. Inokuti, The Optical Properties of Metallic Aluminum. Critiques Semiconductors: E.D. Palik, Cadium Telluride (CdTe) E.D. Palik, Gallium Arsenide (GaAs) A. Borghesi and G. Guizzetti, Gallium Phosphide (GaP) R.F. Potter, Germanium (Ge) E.D. Palik and R.T. Holm, Indium Arsenide (InAs) R.T. Holm, Indium Antimonide (InSb) O.J. Glembocki and H. Piller, Indium Phosphide (InP) G. Bauer and H. Krenn, Lead Selenide (PbSe) G. Guizzetti and A. Borghesi, Lead Sulfide (PbS) G. Bauer and H. Krenn, Lead Telluride (PbTe) D.F. Edwards, Silicon (Si) H. Piller, Silicon (Amorphous) Si) W.J. Choyke and E.D. Palik, Silicon Carbide (SiC) E.D. Palik and A. Addamiano, Zinc Sulfide (ZnS) Critiques Insulators: D.J. Treacy, Arsenic Selenide (As 2 gt Se 3 gt D.J. Treacy, Arsenic Sulfide (As 2 gt S 3 gt D.F. Edwards and H.R. Philipp, Cubic Carbon (Diamond) E.D. Palik and W.R. Hunter, Litium Fluoride (LiF) E.D. Palik, Lithium Niobote (LiNbO 3 gt E.D. Palik, Potassium Chloride (KCl) H.R. Philipp, Silicon Dioxide (SiO 2 gt Type (Crystalline) H.R. Philipp, Silicon Dioxide (SiO 2 gt (Glass) gt H.R. Philipp, Silicon Monoxide (SiO) (Noncrystalline) H.R. Philipp, Silicon Nitride (Si 3 gt N 4 gt (Noncrystalline) J.E. Eldridge and E.D. Palik, Sodium Chloride (NaCl) M.W. Ribarsky, Titanium Dioxide (TiO 2 gt (Rutile)", "author_names": [ "Edward D Palik" ], "corpus_id": 138765507, "doc_id": "138765507", "n_citations": 12904, "n_key_citations": 539, "score": 1, "title": "Handbook of Optical Constants of Solids", "venue": "", "year": 1997 }, { "abstract": "", "author_names": [ "David W Lynch", "William R Hunter" ], "corpus_id": 135471795, "doc_id": "135471795", "n_citations": 4975, "n_key_citations": 204, "score": 0, "title": "Handbook of Optical Constants of Solids", "venue": "", "year": 1985 }, { "abstract": "", "author_names": [ "Oliver S Heavens" ], "corpus_id": 120965652, "doc_id": "120965652", "n_citations": 851, "n_key_citations": 64, "score": 0, "title": "Handbook of Optical Constants of Solids II", "venue": "", "year": 1992 }, { "abstract": "", "author_names": [ "Edward D Palik", "Gorachand Ghosh" ], "corpus_id": 229871481, "doc_id": "229871481", "n_citations": 43, "n_key_citations": 6, "score": 0, "title": "The electronic handbook of optical constants of solids", "venue": "", "year": 1999 }, { "abstract": "We report on the performance of density functional theory (DFT) with the Tran Blaha modified Becke Johnson exchange potential and the random phase approximation dielectric function for optical constants of semiconductors in the ultraviolet visible (UV Vis) light region. We calculate optical bandgaps Eg, refractive indices n, and extinction coefficients k of 70 semiconductors listed in the Handbook of Optical Constants of Solids (Academic Press, 1985) Vol. 1; (Academic Press, 1991) Vol. 2; and (Academic Press, 1998) Vol. 3] and compare the results with experimental values. The results show that the calculated bandgaps and optical constants agree well with the experimental values to within 0.440 eV for Eg, 0.246 0.299 for n, and 0.207 0.598 for k in root mean squared error (RMSE) The small values of the RMSEs indicate that the optical constants of semiconductors in the UV Vis region can be quantitatively predicted even by a low cost DFT calculation of this type.", "author_names": [ "Kousuke Nakano", "Tomohiro Sakai" ], "corpus_id": 103085988, "doc_id": "103085988", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Assessing the performance of the Tran Blaha modified Becke Johnson exchange potential for optical constants of semiconductors in the ultraviolet visible light region", "venue": "", "year": 2018 }, { "abstract": "Lead sulfide (PbS) in thin film form was prepared by thermal evaporation in order to evaluate its optical characteristics. The absorption coefficient of lead sulfide in the 3 11 microns band of the infrared spectrum was calculated under smooth and rough surface conditions. The calculated and measured absorption coefficient was in a good agreement with that published by Semiletov. These results were an order of magnitude higher than that published in the handbook of optical constants of solids and referred to Scanlon.", "author_names": [ "I Elfalla", "Ahmed H Zaki", "Shahriar Alian" ], "corpus_id": 60491254, "doc_id": "60491254", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optical constants of lead sulfide in the 3 11 microns window", "venue": "Proceedings of the Sixteenth National Radio Science Conference. NRSC'99 (IEEE Cat. No.99EX249)", "year": 1999 }, { "abstract": "Historical Figures in Chemistry and Physics Basic Constants, Units, and Conversion Factors Symbols, Terminology, and Nomenclature Physical Constants of Organic Compounds Properties of the Elements and Inorganic Compounds Thermochemistry, Electrochemistry, and Solution Chemistry Fluid Properties Biochemistry Analytical Chemistry Molecular Structure and Spectroscopy Atomic, Molecular, and Optical Physics Nuclear and Particle Physics Properties of Solids Polymer Properties Geophysics, Astronomy, and Acoustics Practical Laboratory Data Health and Safety Information APPENDICES: Mathematical Tables. Sources of Physical and Chemical Data Index", "author_names": [ "Robert C Weast", "Melvin Jensen Astle", "William H Beyer", "Samuel M Selby", "David R Lide", "H P R Frederikse", "William M Haynes", "Thomas J Bruno" ], "corpus_id": 222665132, "doc_id": "222665132", "n_citations": 157, "n_key_citations": 0, "score": 0, "title": "Handbook of chemistry and physics a ready reference pocket book of chemical and physical data", "venue": "", "year": 1922 }, { "abstract": "Maxwell's equations state that a dielectric metallic interface can support surface plasmon polaritons (SPPs) which are coherent electron oscillation waves that propagate along the interface with an electromagnetic wave. The unique properties of the interface waves result from the frequency dependent dispersion characteristics of metallic and dielectric materials. This chapter provides an introduction to alternative plasmonic materials, as well as the rationale for each material choice. The comprehensive optical properties of various materials, including noble metals and semiconductors, are presented. The optical properties are evaluated based on the permittivity and permeability defined by either the Drude or Lorentz model. Furthermore, the noble metals are described from the generally approved data in a general handbook of solid materials, such as the Handbook of Optical Constants of Solids, edited by Palik. This chapter outlines the effective medium approaches for describing the effective dielectric functions of composite nanostructures. It also provides a reference for finding better plasmonic materials at specific frequencies.", "author_names": [], "corpus_id": 44110632, "doc_id": "44110632", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Chapter 1 Optical Properties of Plasmonic Materials", "venue": "", "year": 2017 }, { "abstract": "Maxwell's equations state that a dielectric metallic interface can support surface plasmon polaritons (SPPs) which are coherent electron oscillation waves that propagate along the interface with an electromagnetic wave. The unique properties of the interface waves result from the frequency dependent dispersion characteristics of metallic and dielectric materials. This chapter provides an introduction to alternative plasmonic materials, as well as the rationale for each material choice. The comprehensive optical properties of various materials, including noble metals and semiconductors, are presented. The optical properties are evaluated based on the permittivity and permeability defined by either the Drude or Lorentz model. Furthermore, the noble metals are described from the generally approved data in a general handbook of solid materials, such as the Handbook of Optical Constants of Solids, edited by Palik. This chapter outlines the effective medium approaches for describing the effective dielectric functions of composite nanostructures. It also provides a reference for finding better plasmonic materials at specific frequencies.", "author_names": [ "Yongqian Li" ], "corpus_id": 136378976, "doc_id": "136378976", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Optical Properties of Plasmonic Materials", "venue": "", "year": 2017 }, { "abstract": "S. E. Miller and I. P. Kaminow, Eds. Optical Fiber Telecommunications II, San I. P. Kaminow and A. E. Siegman, Eds. Laser Devices and Applications, IEEE, 1973. I. P. Kaminow, \"Foreword,\" in Handbook of Optical Constants of Solids, I. P. Kaminow, \"Book Review: Integrated Optics: Theory and Technology, ed. If you want to get Handbook of Fiber Optics: Theory and Applications pdf eBook copy write by good author Wolf, Helmut F. you can download the book copy. G. L. Cariolaro, \"Error probability in digital fiber optic communication systems,\" IEEE Trans. M. G. Kendall and A. Stuart, The Advanced Theory of Statistics (Hafer, New detection with application to FSK fiber optic communications,\" IEEE Trans. M. Abramowitz and I. E. Stegun, Handbook of Mathematical Functions (U.S.", "author_names": [ "Helmut F Wolf" ], "corpus_id": 57647747, "doc_id": "57647747", "n_citations": 38, "n_key_citations": 1, "score": 0, "title": "Handbook of fiber optics theory and applications", "venue": "", "year": 1979 } ]

[ { "abstract": "ZigBee is a short range wireless networking standard backed by such industry leaders as Motorola, Texas Instruments, Philips, Samsung, Siemens, Freescale, etc. It supports mesh networking, each node can transmit and receive data, offers high security and robustness, and is being rapidly adopted in industrial, control/monitoring, and medical applications. This book will explain the ZigBee protocol, discuss the design of ZigBee hardware, and describe how to design and implement ZigBee networks. The book has a dedicated website for the latest technical updates, ZigBee networking calculators, and additional materials. Dr. Farahani is a ZigBee system engineer for Freescale semiconductors Inc.Table of ContentsChapter 1: ZigBee BasicsChapter 2: ZigBee IEEE 802.15.4 Networking ExamplesChapter 3: ZigBee IEEE 802.15.4 Protocol LayersChapter 4: Transceiver RequirementsChapter 5: RF Propagation, Antennas, and Regulatory RequirementsChapter 6: Battery Life AnalysisChapter 7: Location Estimating Using ZigBee Chapter 8: ZigBee CoexistenceChapter 9: Related TechnologiesAppendicesKEY FEATURES* Provides a comprehensive overview of ZigBee technology and networking, from RF/physical layer considerations to application layer development. Discusses ZigBee security features such as encryption. Describes how ZigBee can be used in location detection applications. Explores techniques for ZigBee co existence with other wireless technologies such as 802.11 and Bluetooth.", "author_names": [ "Shahin Farahani" ], "corpus_id": 108112680, "doc_id": "108112680", "n_citations": 571, "n_key_citations": 85, "score": 1, "title": "ZigBee Wireless Networks and Transceivers", "venue": "", "year": 2008 }, { "abstract": "Agriculture determines the economic growth of nation and is known to be its backbone. Farmers, researchers, and technical manufacturers are joining efforts to find more efficient solutions for solving various different problems in agriculture to improve current production and processes Precision. The proposed framework for precision agriculture employs low cost environmental sensors, an Arduino Uno prototyping board and a pair of wireless transceivers (XBee ZB S2) along with actuating circuit to provide automated irrigation and monitoring of crops. The proposed prototype uses XBee protocol which is based on ZigBee technology .The important characteristics of ZigBee technology favorable for precision agriculture are; low data rate, low power consumption and larger coverage area. Thus, due to aforesaid characteristics, ZigBee technology happens to be the first choice for implementing precision agriculture. The newly emerging technology i.e. Wireless Sensor Networks spread rapidly into many field's like medical, habitat monitoring, bio technology etc.", "author_names": [ "Shanthi D L", "Mohd Aiman Jaffer", "Harshitha Neelakanta", "M Sowmya", "M Dinesh" ], "corpus_id": 219683453, "doc_id": "219683453", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Comparative Analysis of Smart Irrigation and Crop Prediction using Wireless Sensor Networks and Machine Learning", "venue": "", "year": 2020 }, { "abstract": "This paper presents on the results of radiation studies for three commonly used wireless sensor nodes based on the following protocols: ZigBee, WirelessHART, ISA 100.11a, and network devices built with commercial off the shelf (COTS) components. The level of radiation considered is at par with that experienced at Fukushima Daiichi Nuclear Power Plant after the accident. An experimental setup is developed to monitor behaviors of each wireless device and network real time under the 60 Co gamma radiator at The Ohio State University Nuclear Reactor Lab (OSU NRL) The experimental results have indicated that the performance of the communication channels and wireless signal parameters do not degrade significant under such radiation. However, all the tested devices and networks can only survive for several hours under the high dose rate condition (20 K Rad/h) The results of these experimental studies have provided useful references to those who design and manufacture COTS based wireless monitoring systems for use in high level radiation environments.", "author_names": [ "Q Huang", "J Jiang", "Y Q Deng" ], "corpus_id": 213542672, "doc_id": "213542672", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Comparative Evaluation of Three Wireless Sensor Network Transceivers in a High Radiation Environment", "venue": "", "year": 2020 }, { "abstract": "With the emergence of connected and autonomous vehicles, sensors are increasingly deployed within cars to support new functionalities. Traffic generated by these sensors congest traditional intra car networks, such as CAN buses. Furthermore, the large amount of wires needed to connect sensors makes it harder to design cars in a modular way. To alleviate these limitations, we propose, simulate, and implement a hybrid wired/wireless architecture, in which each node is connected to either a wired interface or a wireless interface or both. Specifically, we propose a new protocol, called Hybrid Backpressure Collection Protocol (Hybrid BCP) to efficiently collect data from sensors in intra car networks. Hybrid BCP is backward compatible with the CAN bus technology, and builds on the BCP protocol, designed for wireless sensor networks. We theoretically prove that an idealized version of Hybrid BCP achieves optimal throughput. Our testbed implementation, based on CAN and ZigBee transceivers, demonstrates the load balancing and routing functionalities of Hybrid BCP and its resilience to DoS attacks and wireless jamming attacks. We further provide simulation results, obtained with the ns 3 simulator and based on real intra car RSSI traces, that compare between the performance of Hybrid BCP and a tree based data collection protocol. Notably, the simulations show that Hybrid BCP outperforms the tree based protocol on throughput by 12 percent. The results also show that Hybrid BCP maintains high packet delivery rate and low packet delay for safety critical sensors that are directly connected to the sink through wire.", "author_names": [ "Wei Si", "David Starobinski", "Moshe Laifenfeld" ], "corpus_id": 53469268, "doc_id": "53469268", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "A Robust Load Balancing and Routing Protocol for Intra Car Hybrid Wired/Wireless Networks", "venue": "IEEE Transactions on Mobile Computing", "year": 2019 }, { "abstract": "In this paper, we study proper routing protocols for border surveillance missions using wireless sensor networks (WSNs) We assume that the sensor nodes are equipped with ZigBee transceivers for wireless communications. Three well known routing algorithms (AODV, DSR, and OLSR) are simulated in a WSN surveillance scenario. The performances of these routing algorithms are compared in terms of traffic load, delay, packet loss, and energy consumption. Our results indicate that DSR performs better than other algorithms for border surveillance applications. Moreover, a novel algorithm called \"DSR_OP\" is proposed for improving DSR routing in terms energy management in the network and extending the network life time. However Comparisons of WSN routing protocols (DSR, AODV, OLSR and others) are presented since many years ago, but there is no simulation with OPNET, so our novelty is that the validity of proposed method and the comparisons are confirmed by simulations in OPNET.", "author_names": [ "Hoda Sharei-Amarghan", "Alireza Keshavarz-Haddad", "Gaetan Garraux" ], "corpus_id": 37786246, "doc_id": "37786246", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Routing Protocols for Border Surveillance Using ZigBee Based Wireless Sensor Networks", "venue": "CN", "year": 2013 }, { "abstract": "Wireless sensor networks have been used in several applications to perform remote monitoring for a certain Area of Interest. In this work, we propose to utilize an Unmanned Aerial Vehicle (UAV) to improve the ground network connectivity, act as a data mule that collects the captured data and off load the ground sensor nodes, who have normally limited storage capacities. We have investigated the effect of several parameters that affect the communication between the UAV and the ground sensors such as the UAV height, communication channel weather conditions, and nodes' noise factor, and evaluated the network performance measured by the average packet loss rate, end to end delay, and throughput. We found out that when the nodes' transceivers have a relatively high noise factor (above 20) it is recommended to keep the UAV altitude around 150 meters or below. We also noticed that the performance degrades drastically when having severe weather conditions, which requires additional mechanisms for improving the transmission performance such as the usage of error correction codes and Multiple Input Multiple Output antennas.", "author_names": [ "Ala F Khalifeh", "Mahmoud AlQudah", "Rabi Tanash", "Khalid A Darabkh" ], "corpus_id": 57191071, "doc_id": "57191071", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "A Simulation Study for UAV Aided Wireless Sensor Network Utilizing ZigBee Protocol", "venue": "2018 14th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob)", "year": 2018 }, { "abstract": "1171 Published By: Blue Eyes Intelligence Engineering Sciences Publication Retrieval Number G6350058719/19(c)BEIESP Abstract: Wireless Sensor networks finds its application in various areas such as habitat monitoring, home automation, industrial automation, military applications and health care etc. Even though Wireless sensor networks are omnipresence, they are vulnerable to the various security threats. Sybil attacks are considered to be one of the most important attacks for which the several detection algorithms and systems were designed and implemented. But still the existing algorithms need intelligence for better accuracy of detection. Hence new technique FEM(Fuzzy Extreme machines) is proposed which works on the hybrid Fuzzy and powerful Extreme learning machines for the detection of Sybil attacks. The experiments were conducted on real time Testbeds which consist of ARM as main CPU interfaced with CC2530 Zigbee transceivers and tested in LEACH environment. Results in terms of accuracy detection obtained from the FEM approach proves to be more vital when compared with the other existing classifier algorithms.", "author_names": [ "V Sujatha", "E A Mary Anita" ], "corpus_id": 212442406, "doc_id": "212442406", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "FEM Hybrid Machine Learning Approach for the Detection of Sybil attacks in the Wireless Sensor Networks", "venue": "", "year": 2019 }, { "abstract": "This chapter introduces concepts and applications relating to wireless data communication. It starts with a review of the principles, including the electromagnetic spectrum, radio transceivers, protocols and antennae. The background to short distance, personal area network protocols is introduced, through reference to IEEE Working Groups. Bluetooth is introduced, and trialled using the RN 41 Bluetooth module. The RN 41 is used to develop key Bluetooth concepts. Simple PC to mbed, and mbed to mbed Bluetooth links are demonstrated. The Zigbee protocol, its typical networks and applications are introduced. XBee radio modules are used to illustrate simple Zigbee links, in Transparent mode. Use of the XBee in its more flexible API mode is then introduced, which opens the door to more advanced Zigbee applications.", "author_names": [ "Rob Toulson", "Tim Wilmshurst" ], "corpus_id": 114638774, "doc_id": "114638774", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Chapter 11 Wireless Communication Bluetooth and Zigbee", "venue": "", "year": 2017 }, { "abstract": "Wireless sensor networks are important for a variety of today's applications and a high impact in the domains of Internet of Things (IoT) smart grids, smart dust and industrial wireless networks can be expected for the coming years. Even if constantly new created protocols try to achieve common standards, the interoperability remains still a big problem. In this work we propose a new approach, in which we abstract existing protocols in a unified application programming interface (API) realizing a transparent protocol. The proposed API provides the same functions for different platforms and can be easily implemented to operate with several communication solutions. For proof of concept, the transparent protocol is developed, implemented and tested using two heterogeneous transceivers and communication protocols, which are ZigBee and Xbee. Both solutions are accessed using the same program. The data of heterogeneous endpoints is extracted, stored in a common database and visualized in a shared front end.", "author_names": [ "Martin Gotz", "Olfa Kanoun" ], "corpus_id": 52283176, "doc_id": "52283176", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Transparent Protocol for Interoperability in Wireless Sensor Networks", "venue": "2018 International Conference on Advances in Big Data, Computing and Data Communication Systems (icABCD)", "year": 2018 }, { "abstract": "Display Omitted We measure and model the path loss for wireless links in low voltage substations.No effect of EMI on Zigbee links is normally observed in high voltage substations.The probability of unsuccessful polling transactions Put is analytically studied.Sending multiple copies of data by WiFi 5GHz transmitters achieves near zero Put. Supervisory control and data acquisition (SCADA) systems currently use the polling technique for monitoring electric utility networks. Unfortunately, conventional SCADA systems do not suit the needs of smart grids in terms of the required data rate. Polling based wireless networks can extend the capabilities of SCADA systems as they provide low cost transceivers and bounded packet delay. However, the harsh environment of power stations negatively impacts the performance of wireless links. This paper introduces a field measurement based study that focuses on the effect of power system noise and transients on packet delivery reliability of Zigbee and WiFi polling based wireless networks. Extensive experiments show that the electromagnetic interference emitted from high voltage substations, during normal operation conditions, do not significantly affect wireless communication in the gigahertz range. Moreover, we analytically and experimentally demonstrate that abnormal operation conditions of power systems may negatively impact the reliability of packet delivery in polling based wireless networks. Furthermore, we show that this negative impact can be mitigated by following some proposed technical considerations regarding the wireless standard, the operating frequency, the location, and the number of wireless transceivers used.", "author_names": [ "Atef Abdrabou", "Ahmed M Gaouda" ], "corpus_id": 1629005, "doc_id": "1629005", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Considerations for packet delivery reliability over polling based wireless networks in smart grids", "venue": "Comput. Electr. Eng.", "year": 2015 } ]

[ { "abstract": "Highly accurate and thoroughly updated, this book has set the standard in electronic devices and circuit theory for over 28 years. Boylestad and Nashelsky offer readers a complete and comprehensive survey of electronics and circuits, focusing on all the essentials they will need to succeed on the job. This very readable book is supported by strong, helpful learning cues and content that is ideal for new workers in this rapidly changing field. Its colorful layout boasts a large number of stunning photographs. Topics covered include: semiconductor diodes, BJT devices, DC biasing, FET devices, Op Amp applications, power amplifiers, linear digital ICs, power supplies and voltage regulators, and other two terminal devices. An excellent reference work for anyone involved with electronic devices and other circuitry applications, such as electrical and technical engineers.", "author_names": [ "Robert L Boylestad", "Louis Nashelsky" ], "corpus_id": 110223744, "doc_id": "110223744", "n_citations": 434, "n_key_citations": 26, "score": 1, "title": "Electronic Devices and Circuit Theory", "venue": "", "year": 1972 }, { "abstract": "Eventually, you will totally discover a further experience and feat by spending more cash. yet when? realize you take that you require to get those all needs later having significantly cash? Why don't you attempt to acquire something basic in the beginning? That's something that will lead you to understand even more going on for the globe, experience, some places, bearing in mind history, amusement, and a lot more?", "author_names": [ "Robert L Boylestad" ], "corpus_id": 195942474, "doc_id": "195942474", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Electronic devices and circuit theory 11th edition", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "Dobri Atanassov Batovski" ], "corpus_id": 64100162, "doc_id": "64100162", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Review of the Eleventh Edition of \"Electronic Devices and Circuit Theory\"", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "Robert L Boylestad", "Louis Nashelsky" ], "corpus_id": 86624397, "doc_id": "86624397", "n_citations": 9, "n_key_citations": 1, "score": 1, "title": "Electronic devices and circuit theory, 4th ed.", "venue": "", "year": 1987 }, { "abstract": "", "author_names": [ "Robert L Boylestad", "Louis Nashelsky" ], "corpus_id": 60914864, "doc_id": "60914864", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Electronic devices and circuit theory (6th ed.", "venue": "", "year": 1996 }, { "abstract": "", "author_names": [ "V B Kitovski" ], "corpus_id": 110017599, "doc_id": "110017599", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Electronic devices and circuit theory, 6th edition, R. Boylestad and L. Nashelsky, Prentice Hall International Inc. 1996, 950 pp. A4 (paperback)", "venue": "", "year": 1998 }, { "abstract": "Electronic Devices and Circuit Theory (2nd ed. R. BOYLESTAD and L. NASHELSKY (Prentice Hall, 1978, 701 pp. xvi, PS12.55) Designed primarily for use alongside courses in basic electronics, this book reviews electronic devices and examines their circuit properties and applications. Limitations of space are presumably one of the reasons why only brief descriptions of such basic devices as the pn junction diode and bipolar transistor have been provided, giving an essentially qualitative picture of how they function. Although useful as an introductory survey of devices and their elementary properties, a student wanting to acquire deeper knowledge in this area would need to look elsewhere. It is surprising to find sections dealing with valvesbeing included in a book that has only recently been revised. While not disputing the considerable historical significance of these devices, it is extremely unlikely that descriptions of their construction, properties and circuit applications would fmd their way into any modern electronics course. In preparing the text for this second edition, the authors should have considered omitting valves altogether in favour of more extensive coverage of semiconductor devices. Greater emphasis could then have been placed on the importance of developments that have taken place in recent years. As it stands, the book deals fairly thoroughly with devices such as F .E.T.'s and briefly describes a number of modern components such as liquid crystal displays and V F.E.T.'s.lntegrated circuit operational amplifiers and their applications are described using the RCA CA3000 as a practical example, while a well illustrated chapter takes a brief look at the processes involved in the design and fabrication of integrated circuits. Pulse and digital circuits are surveyed in a single chapter which serves as an introduction to basic logic elements and simple integrated circuit logic devices. The majority of the book, however, consists of a fairly conventional treatment of electronic circuit theory with the emphasis on linear behaviour. The chapter headings include topics such as diode rectifiers and filters, bipolar transistors and d.c, biasing, small signalanalysis, F.E.T.'s, multistage systems, largesignal amplifiers and feedback amplifiers and oscillators. One of the later chapters describes a handful of miscellaneous circuits intended as applications examples, including an S.C.R. motor speed controller and a high impedance F.E.T. voltmeter. The final chapter of the book is devoted entirely to an introduction to the cathode ray oscilloscope, its operation and uses. Presented at a very elementary level, this material would be useful to students meeting the oscilloscope in the laboratory for the first time. The text provides a thorough treatment of basic circuit theory supported by numerous, carefully worked, practical examples and an abundance of clear diagrams and illustrations. However, although well presented and bound in hard covers, the 'price may be a little high for an undergraduate textbook. Compared with the wide range of titles already available on this subject, the book seems to have few outstanding advantages. P. J. HICKS, Department ofElectrical Engineering and Electronics, UM J.S. T.", "author_names": [ "Paul J Hicks" ], "corpus_id": 112046707, "doc_id": "112046707", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Electronic Devices and Circuit Theory (2nd Ed.", "venue": "", "year": 1979 }, { "abstract": "", "author_names": [ "Robert L Boylestad" ], "corpus_id": 54135395, "doc_id": "54135395", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Electronic devices and circuit theory Robert Boylestad, Louis Nashelsky", "venue": "", "year": 2000 }, { "abstract": "Development tools were described to assist in the fashioning of a specification and at the programming level to assist in checking the programmes and the interprogramming communication which occurs on a large project. Development systems to support automatic programme generation are also included. Design techniques particularly appropriate for telecommunication switching systems were described, including a methodology which includes a compatible specification system. Various operating systems and architectural features were described including operating systems for realtime architecture and a discussion of the particular problems of package switched networks and fault handling within a multiprocessor system. The section on testing and modelling included papers on the problem of overload in multiprocessor systems, also the inclusion of particular aspects of testing within certain existing systems. The first CHILL session was concerned with the implementation of the language whilst the second gave some indication of its application and also included a comparative study of CHILL and ADA, the language being proposed as a standard by the U.S. Department of Defence. The collection of papers provides an excellent record ofthe state ofthe art in 1981 and should be included in the library of departments of Computer Science and those departments of Electrical Engineering which have a close affinity to software engineering. This collection of papers confirms the view that there is a growing need for close interaction between electrical and electronic engineers and the computer science community, not only in the workplace but also in the provision of undergraduate and postgraduate courses for the education of the new engineer who is able to interwork the hardware and software of complex systems. (The reviewer wishes to acknowledge the help of John Forrest, a research student in the Department of Computation, UMIST for his contributions to a lively discussion on many of the papers included in this publication. D. ASPINALL, Professor ofComputation. UMIST.", "author_names": [ "Frank Atkinson Benson" ], "corpus_id": 64697727, "doc_id": "64697727", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Electronic Devices and Circuit Theory, 3rd Ed.", "venue": "", "year": 1983 }, { "abstract": "", "author_names": [ "Brian M Shaw" ], "corpus_id": 116098006, "doc_id": "116098006", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Electronic Devices and Circuit Theory (4th Ed.", "venue": "", "year": 1988 } ]

[ { "abstract": "This study examined the antecedents of an individual's creative self efficacy (CSE) using a sample of 41 semiconductor design teams. Drawing from social cognitive theory, we expected that a dynamic interaction of an individual's learning goal orientation, creativity as a job requirement, and team learning behavior would build CSE. In addition, employing the combinational perspective, we conjectured that consistency among the three antecedents would enhance CSE, and subsequently, creative performance. As predicted, results showed that effects of learning goal orientation and job requirement on CSE were subject to other members' learning behavior. A significant three way interaction supported the position that individual contextual congruence facilitates the development of CSE, while incongruence of these factors impedes such development. Implications for theory and human resource practices are discussed in light of these findings. JEL Classification: M54, O32", "author_names": [ "Hao Kong", "Warren C K Chiu", "Humphrey Kw Leung" ], "corpus_id": 158262546, "doc_id": "158262546", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Building creative self efficacy via learning goal orientation, creativity job requirement, and team learning behavior: The key to employee creativity", "venue": "", "year": 2019 }, { "abstract": "We identify the creative requirement of a job as a neglected predictor of employee creativity and propose that it may account for relationships between traditional work factors and creativity. As such, it may represent a more effective means of increasing creativity than changes in job design. Using structural equation modeling, we tested this model against four competing models using a sample of 1,083 health service employees. Creative requirement was found to account for much of the variance by fully mediating the effects of supportive leadership and role requirements and partially mediating those of empowerment and time demands. We conclude that creative requirement is an important proximal determinant of employee creativity and a potentially significant intervention.", "author_names": [ "Kerrie L Unsworth", "Toby D Wall", "Angela J Carter" ], "corpus_id": 142584707, "doc_id": "142584707", "n_citations": 140, "n_key_citations": 8, "score": 1, "title": "Creative Requirement", "venue": "", "year": 2005 }, { "abstract": "We identify the creative requirement of a job as a neglected predictor of employee creativity and propose that it may account for relationships between traditional work factors and creativity. As such, it may represent a more effective means of increasing creativity than changes in job design. Using structural equation modeling, we tested this model against four competing models, using a sample of 1083 health service employees. Creative requirement was found to account for much of the variance by fully mediating the effects of supportive leadership and role requirements and partially mediating those of empowerment and time demands. We conclude that creative requirement is an important proximal determinant of employee creativity and a potentially significant intervention.", "author_names": [ "Kerrie L Unsworth", "Toby D Wall", "Angela J Carter" ], "corpus_id": 219383119, "doc_id": "219383119", "n_citations": 27, "n_key_citations": 2, "score": 0, "title": "Creative Requirement: A Neglected Construct in the Study of Employee Creativity?", "venue": "", "year": 2005 }, { "abstract": "Training of professional personnel always takes place on a certain territory. But results of creative personnel's work go beyond the boundaries of a particular city and extend to a considerable space, for example, the space of urban agglomerations or inter regional agglomerated space. There is a negative trend in the desire of creative people to choose a large city with an atmosphere of creativity and the need of the territory of the metropolitan area for creative personnel as a place of residency and work. Thus, a peculiar creative inequality occurs on a certain territory. The spatial distribution of creative personnel in Russia is manifested in the concentration of elements of the creative economy primarily in the European part of the country. It is emphasized that the accelerated development of creative economy is possible through the creation of a specific creative spatial cluster, which emerges on the basis of nearby agglomerations with different levels of creative appeal. Implementation of creative component of the innovation process imposes certain requirements on the real and potential subject of innovation. Novelty of the research lies in the development of methods for the gradual assessment of an employee's creativity level: the definition of the employee category to be assessed; the definition of a set of indicators reflecting the employee's creativity; the determination of each indicator's weight, based on the method of expert assessment; the integral assessment of creativity level according to the author's method, which was tested and which displayed the possibility of its use. (c) 2019 Published by Future Academy www.FutureAcademy.org.UK", "author_names": [ "L L Zobova" ], "corpus_id": 169806324, "doc_id": "169806324", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Training Of Professionals For Creative Economy In Agglomeration", "venue": "", "year": 2019 }, { "abstract": "Over the years, researchers have focused on ways to facilitate creativity in the workplace by looking at individual factors and organizational factors that affect employee creativity (Woodman, Sawyer, Griffin, 1993) In many cases, the factors that affect creativity are examined independently. In other words, it is uncommon for researchers to look at the interaction among individual and organizational factors. In this study, it is argued that to get a true understanding of how to maximize creativity in the workplace, organizational researchers must look at the interaction between organizational factors and individual factors that affect employee creativity. More specifically, the current study looked at an individual's perceptions about his or her ability to be creative (i.e. individual factor) and perceptions of requirements for creativity in the workplace (i.e. an organizational factor) The results indicated that individuals who have a high belief about their ability to be creative (an individual factor) were most creative when they also perceived requirements for creativity in the workplace (an organizational factor) Furthermore, individuals who had low perceptions of creative ability were still able to perform creatively when they had high perceptions of requirements for creativity. This suggests that, to maximize creativity, organizations should focus on both individual and organizational factors that affect employee creativity.", "author_names": [ "Erika J Robinson-Morral", "Roni Reiter-Palmon", "J Kaufman" ], "corpus_id": 143324836, "doc_id": "143324836", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "The interactive effects of self perceptions and job requirements on creative problem solving", "venue": "", "year": 2013 }, { "abstract": "Employee creativity is very important for enhancing enterprise innovation ability to seize the opportunity in fierce competition. Based on the componential theory of creativity, this paper explores the influence of creativity relevant skills on creativity through the transmission mechanism with Chinese characteristics. It has been found that creativity relevant skills promote creativity has a dual path by enhancing creativity role identification and weakening mental transformation costs. At the same time, creative job requirement not only significantly regulate the positive and negative relationship between creativity role identity, mental transformation costs and creativity, but also significantly moderated the mediating effect of creativity relevant skills on creativity through creative role identity and mental transformation costs. Managers should clarify the mechanism and focus on improving their creativity relevant skills, so as to enhance their overall innovation capability.", "author_names": [ "Jianglin Ke" ], "corpus_id": 212581665, "doc_id": "212581665", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Influence of Creativity Relevant Skill on Creativity A Moderated Mediation Model", "venue": "", "year": 2018 }, { "abstract": "Employee creativity is very important for enhancing enterprise innovation ability to seize the opportunity in fierce competition. Based on the componential theory of creativity, this paper explores the influence of creativity relevant skills on creativity through the transmission mechanism with Chinese characteristics. It has been found that creativity relevant skills promote creativity has a dual path by enhancing creativity role identification and weakening mental transformation costs. At the same time, creative job requirement not only significantly regulate the positive and negative relationship between creativity role identity, mental transformation costs and creativity, but also significantly moderated the mediating effect of creativity relevant skills on creativity through creative role identity and mental transformation costs. Managers should clarify the mechanism and focus on improving their creativity relevant skills, so as to enhance their overall innovation capability. Keywords: creativity relevant skills; creativity role identity; mental transformation costs; creative job requirement; creativity", "author_names": [ "Jianglin Ke" ], "corpus_id": 149916327, "doc_id": "149916327", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Influence of Creativity Relevant Skill on Creativity A Moderated Mediation Model", "venue": "", "year": 2018 }, { "abstract": "Employee creativity and corporate innovation have become important topics in management literature. Because the broadcast industry is dependent upon entertainment to attract viewers and listeners, most radio and television stations are staffed by artistic, creative personnel. These creative employees do not always respond to standard management and motivational techniques. Recent theories focus upon the end product to define creativity. Artists, however, often consider the process of creativity as more important than the final product. A new modified process definition of creativity is suggested in which the artistic concerns of production personnel and the goal oriented business requirements of management combine to form a structured system for creative endeavors. Characteristics of creative people are discussed along with techniques to manage creative personnel.", "author_names": [ "Randall K Scott" ], "corpus_id": 145539482, "doc_id": "145539482", "n_citations": 61, "n_key_citations": 1, "score": 0, "title": "Creative Employees: A Challenge to Managers", "venue": "", "year": 1995 }, { "abstract": "Over twenty years ago, Peters and Waterman posited that the best run companies had simultaneous \"loose tight\" properties, where the organization is \"rigidly controlled, yet at the same time autonomy, entrepreneurship and innovation from the rank and file is encouraged\" (1982: 318) More recently, Collins (2001) has suggested that what he terms \"great\" companies have a \"culture of discipline,\" where rigor and discipline enable creativity and entrepreneurship. This creative duality is expressed in terms of \"freedom within a framework\" and \"opportunistic flexibility.\" The inference of these widely read examinations of corporate excellence is that corporate control systems play an instrumental role in companies that demonstrate high levels of entrepreneurship. Yet the nature of that role remains unclear. Control systems evolve in companies. The implementation of measures, procedures, systems, and documentation requirements initially brings order, coordination, accountability and efficiency to an otherwise chaotic situation. Without them, quality is inconsistent, schedules are missed, customers are improperly billed, money is wasted, and employees take shortcuts. Simple in the beginning, controls become more sophisticated and complex over time, to the point that they encourage bureaucracy and micro management (Shih and Yong, 2001) Control measures can become ends in themselves, while conveying a lack of employee trust (Morrow et al. 2004) Concerns for strategic effectiveness are replaced by a preoccupation with operational efficiency (Simons, 1995) Thus, Pinchot observes that \"many centralized companies with highly sophisticated control systems are, in fact, out of control\" (2000: 125) while Govindarajan (1988) has proposed that U.S. firms are not so much over controlled as they are mis controlled. A critical question concerns the relationship between the design and operation of the control system and the level of entrepreneurship exhibited within the organization. On the one hand, control systems provide strategic direction to the innovative efforts of firms, and the efficiencies they produce can free up resources for innovation (Marginson, 2002) Further, they exert discipline over innovative projects in terms of performance benchmarks, schedules, and competition among ideas. On the other hand, it would seem control systems that tightly monitor behavior and resource utilization can serve to undermine employee creativity and the motivation to experiment and take risks (Morris and Kuratko, 2002; Shih and Yong, 2001) Elaborate controls can discourage the kind of bootleg projects, resource bootstrapping, and informal arrangements between departments and units that are frequently associated with corporate entrepreneurship (Pinchot, 2000) They can result in slower decision making, harming the ability of the firm to exploit new opportunities. The purpose of this research is to empirically assess the relationship between control and entrepreneurship in established organizations. Insights from the literature on the nature of control are reviewed, and underlying dimensions of a control system are identified. A series of hypotheses concerning relationships between the components of control and the level of entrepreneurship in a company are proposed. The hypotheses are tested via two surveys directed at cross sections of corporate managers. Implications are drawn for theory and practice. ENTREPRENEURSHIP IN AN ORGANIZATIONAL CONTEXT Stevenson and Jarillo Mossi indicate that \"entrepreneurship is a process by which individuals either on their own or inside organizations pursue opportunities without regard to the resources they currently control\" (1990: 23) Sathe (2003) defines corporate entrepreneurship as a process of organizational renewal and new business creation. Others have noted that, in a corporate context, entrepreneurial activities revolve around organizational sanctions and resource commitments for the purpose of innovative results (Naman and Slevin, 1993; Zahra and Covin, 1995)", "author_names": [ "Michael H Morris", "Jeff Allen", "Minet Schindehutte", "Ramon A Avila" ], "corpus_id": 150531843, "doc_id": "150531843", "n_citations": 75, "n_key_citations": 3, "score": 0, "title": "Balanced management control systems as a mechanism for achieving corporate entrepreneurship", "venue": "", "year": 2006 }, { "abstract": "Prior research on creativity highlights a conflicting pattern of results. Job complexity and creativity requirements, two contextual variables common in many creative environments, place demands on employees that can have positive and negative effects on employees' creativity by influencing experience of positive affect (PA) We aim to resolve this conflict by drawing upon the job demands resources perspective to propose that emotional intelligence (EI) is a key internal resource employees use in order to respond positively to the demands created by job complexity and creativity requirements. We argue that the EI facet of emotion regulation ability enables employees to better cope with demands, which subsequently leads to higher levels of PA. Furthermore, the EI facet of emotion facilitation ability enables employees to utilize PA for creative outcomes. We test our hypotheses through a multi method (e.g. ability test, experience sampling, survey) and multi source (archival, self reported, manger reported.", "author_names": [ "Michael R Parke", "Myeong-gu Seo" ], "corpus_id": 145165168, "doc_id": "145165168", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "The Emotional Edge: Creativity under Job Complexity and Creativity Requirements", "venue": "", "year": 2013 } ]

[ { "abstract": "Corrosion protection has become an important issue as the amount of infrastructure construction in marine environment increased. Photocathodic protection is a promising method to reduce the corrosion of metals, and titanium dioxide (TiO2) is the most widely used photoanode. This review summarizes the progress in TiO2 photogenerated protection in recent years. Different types of semiconductors, including sulfides, metals, metal oxides, polymers, and other materials, are used to design and modify TiO2. The strategy to dramatically improve the efficiency of photoactivity is proposed, and the mechanism is investigated in detail. Characterization methods are also introduced, including morphology testing, light absorption, photoelectrochemistry, and protected metal observation. This review aims to provide a comprehensive overview of TiO2 development and guide photocathodic protection.", "author_names": [ "Xiutong Wang", "Hui Xu", "Youbo Nan", "Xin Sun", "Jizhou Duan", "Yan-liang Huang", "Bao-rong Hou" ], "corpus_id": 220437918, "doc_id": "220437918", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Research progress of TiO2 photocathodic protection to metals in marine environment", "venue": "Journal of Oceanology and Limnology", "year": 2020 }, { "abstract": "Photocelectrochemistry is a vigorous research area in chemistry that has drawn strong interest in recent years. In this field, numerous papers are being presented, and international symposiums are frequently held. This report reviews the origins of photoelectrochemistry and its progress to date.", "author_names": [ "Kenichi Honda" ], "corpus_id": 96541495, "doc_id": "96541495", "n_citations": 31, "n_key_citations": 1, "score": 1, "title": "Dawn of the evolution of photoelectrochemistry", "venue": "", "year": 2004 }, { "abstract": "This article focuses on the promise, problems and progress of utilizing hematite for photocatalyzed water oxidation. Issues which require further research are also presented.", "author_names": [ "Thomas W Hamann" ], "corpus_id": 20395352, "doc_id": "20395352", "n_citations": 154, "n_key_citations": 1, "score": 0, "title": "Splitting water with rust: hematite photoelectrochemistry.", "venue": "Dalton transactions", "year": 2012 }, { "abstract": "Photoelectrochemistry is avery active research field.It is apractically applied basis for photoelectron volt cell,photolysis and photoelectricity synthesise,photoelectricity catalysis and so on.In addition,photoelectrochemistry is an important research means of studying surface action of metal oxide passivation membrane and semiconductor ultrafine powders photoelectric change mechanism too.", "author_names": [ "Luo Fang" ], "corpus_id": 101457886, "doc_id": "101457886", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photoelectrochemistry Special Property and Study Progress", "venue": "", "year": 2000 }, { "abstract": "Research on doping iron oxide for the purpose of enhancing its photoelectrochemical properties is briefly described. (WHK)", "author_names": [ "John Hines Kennedy" ], "corpus_id": 203915167, "doc_id": "203915167", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photoelectrochemistry at iron oxide electrodes. Progress report", "venue": "", "year": 1980 }, { "abstract": "The tremendous amount of research that has been carried out in the two closely related fields of semiconductor photoelectrochemistry and photocatalysis during the past three decades continues to provide fundamental insights and practical applications. The present review paper will attempt to describe some of the progress and resulting achievements in these two areas and to briefly discuss the future prospects. In order to provide a focal point, we will highlight work carried out in Japan over the last 5 years. However, we will try as much as possible to put this work into a global and historical context by tracing some of the key developments that have occurred outside this relatively narrow scope. We should note at the outset that we have made no attempt to cover the underlying theory or physics of photoelectrochemistry. Several excellent reviews have appeared during this same time period that cover fundamental and general aspects of photoelectrochemistry and photocatalysis.", "author_names": [ "Donald A Tryk", "Akira Fujishima", "Kenichi Honda" ], "corpus_id": 96523658, "doc_id": "96523658", "n_citations": 442, "n_key_citations": 1, "score": 0, "title": "Recent topics in photoelectrochemistry: achievements and future prospects", "venue": "", "year": 2000 }, { "abstract": "Abstract In the past two years, foundational early stage materials research through DOE's HydroGEN Consortium has successfully brought together resources and expertise from industry, academia and the national laboratories to expedite progress in hydrogen production by water splitting. There is an enormous untapped opportunity to extract hydrogen from water using diverse thermal, chemical and electrochemical process available today at different stages of maturity that can be powered using fossil, nuclear and/or renewable energy. Ongoing development and scale up of these processes relies on continued scientific and technological innovation, including identification and optimization of new low cost, high performance materials for energy conversion, heat transfer, separations, and catalysis. The scientific innovations and accomplishments to date from HydroGEN supported research are discussed, including impressive results in thermochemistry and photoelectrochemistry, as well as low and high temperature electrolysis.", "author_names": [ "Eric L Miller", "Katie Randolph", "David Peterson" ], "corpus_id": 139665571, "doc_id": "139665571", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "The HydroGEN Consortium: Foundational early stage water splitting research supporting diversification of the domestic hydrogen supply chain", "venue": "", "year": 2018 }, { "abstract": "Abstract Boron doped diamond materials display excellent electrochemical properties, including large potential windows, low background currents, the ability to withstand extreme potentials, and a strong tendency to resist contamination. These materials have been well studied in the field of electrochemistry by a variety of methods and advanced characterization techniques. This review highlights recent progress and achievements of boron doped diamond in photoelectrochemical applications. After surface modification of boron doped diamond (e.g. with metals, metal oxides, molecular catalysts, enzymes, etc. boron doped diamond has demonstrated excellent electrochemical and photoelectrochemical properties. Applications in the fields of photoelectrocatalysis, environmental pollutants degradation, energy conversion and (photo)electroanalysis are discussed. Moreover, the challenges and future research directions of boron doped diamond photoelectrochemistry are discussed and outlined. This review would provide valuable theoretical guidance for boron doped diamond photoelectrochemistry.", "author_names": [ "Chenyan Guo", "Jingui Zheng", "Hongwei Deng", "Penghui Shi", "Guohua Zhao" ], "corpus_id": 230597800, "doc_id": "230597800", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Photoelectrocatalytic interface of boron doped diamond: Modification, functionalization and environmental applications", "venue": "", "year": 2020 }, { "abstract": "The direct conversion of solar energy into chemical fuels, such as hydrogen, via photoelectrochemical (PEC) water splitting requires the efficient oxidation of water at a photoanode. While transition metal oxides have shown a significant success as photoanodes, their intrinsic limitations make them the bottleneck of PEC water splitting. Recently, initial research reports suggest that organic semiconductors (OSCs) could be possible alternative photoanode materials in both dye sensitized and thin film photoelectrode configurations. Herein we review the progress to date, with a focus on the major issues faced by OSCs: stability and low photocurrent density in aqueous photoelectrochemical conditions. An outlook to the future of OSCs in photoelectrochemistry is also given.", "author_names": [ "Arvindh Sekar", "Kevin Sivula" ], "corpus_id": 232367332, "doc_id": "232367332", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Organic Semiconductors as Photoanodes for Solar driven Photoelectrochemical Fuel Production.", "venue": "Chimia", "year": 2021 }, { "abstract": "The field of heterogeneous photocatalysis has grown considerably in the decades since Fujishima and Honda's ground breaking publications of photoelectrochemistry on TiO2. Numerous review articles continue to point to both progress made in the use of heterogeneous materials (such as TiO2) to perform photoconversion processes, and the many opportunities and challenges in heterogeneous photocatalysis research such as solar energy conversion and environmental remediation. The past decade has also seen an increase in the use of molecular level approaches applied to model single crystal surfaces in an effort to obtain new insights into photocatalytic phenomena. In particular, scanning probe techniques (SPM) have enabled researchers to take a 'nanoscale' approach to photocatalysis that includes interrogation of the reactivities of specific sites and adsorbates on a model photocatalyst surface. The rutile TiO2(110) surface has become the prototypical oxide single crystal surface for fundamental studies of many interfacial phenomena. In particular, TiO2(110) has become an excellent model surface for probing photochemical and photocatalytic reactions at the molecular level. A variety of experimental approaches have emerged as being ideally suited for studying photochemical reactions on TiO2(110) including desorption oriented approaches and electronic spectroscopies, but perhaps the most promising techniques for evaluating site specific properties are those of SPM. Inmore this review, we highlight the growing use of SPM techniques in providing molecular level insights into surface photochemistry on the model photocatalyst surface of rutile TiO2(110) Our objective is to both illustrate the unique knowledge that scanning probe techniques have already provided the field of photocatalysis, and also to motivate a new generation of effort into the use of such approaches to obtain new insights into the molecular level details of photochemical events occurring at interfaces. Discussion will start with an examination of how scanning probe techniques are being used to characterize the TiO2(110) surface in ways that are relevant to photocatalysis. We will then discuss specific classes of photochemical reaction on TiO2(110) for which SPM has proven indispensible in providing unique molecular level insights, and conclude with discussion of future areas in which SPM studies may prove valuable to photocatalysis on TiO2. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences Biosciences. I.L. was partially supported by a Pacific Northwest National Laboratory (PNNL) Chemical Imaging Initiative project. PNNL is a multiprogram national laboratory operated for DOE by Battelle. less", "author_names": [ "Michael A Henderson", "I V Lyubinetsky" ], "corpus_id": 33678204, "doc_id": "33678204", "n_citations": 189, "n_key_citations": 0, "score": 0, "title": "Molecular level insights into photocatalysis from scanning probe microscopy studies on TiO2(110)", "venue": "Chemical reviews", "year": 2013 } ]

[ { "abstract": "In the context of personalized oncology, screening for somatic tumor mutations is crucial for prediction of an individual patient's response to therapy. Massive parallel sequencing (MPS) has been suggested for routine diagnostics, but this technology has not been sufficiently evaluated with respect to feasibility, reliability, and cost effectiveness with routine diagnostic formalin fixed, paraffin embedded material. We performed ultradeep targeted semiconductor based MPS (190 amplicons covering hotspot mutations in 46 genes) in a variety of formalin fixed, paraffin embedded diagnostic samples of lung adenocarcinoma tissue with known EGFR mutations (n 28) The samples reflected the typical spectrum of tissue material for diagnostics, including small biopsies and samples with low tumor cell content. Using MPS, we successfully sequenced all samples, with a mean read depth of 2947 reads per amplicon. High quality sequence reads were obtained from samples containing =10% tumor material. In all but one sample, variant calling identified the same EGFR mutations as were detected by conventional Sanger sequencing. Moreover, we identified 43 additional mutations in 17 genes and detected amplifications in the EGFR and ERBB2 genes. MPS performance was reliable and independent of the type of material, as well as of the fixation and extraction methods, but was influenced by tumor cell content and the degree of DNA degradation. Using sample multiplexing, focused MPS approached diagnostically acceptable cost rates.", "author_names": [ "Volker Endris", "Roland Penzel", "Arne Warth", "Alexander Muckenhuber", "Peter Schirmacher", "Albrecht Stenzinger", "Wilko Weichert" ], "corpus_id": 206239672, "doc_id": "206239672", "n_citations": 107, "n_key_citations": 11, "score": 0, "title": "Molecular diagnostic profiling of lung cancer specimens with a semiconductor based massive parallel sequencing approach: feasibility, costs, and performance compared with conventional sequencing.", "venue": "The Journal of molecular diagnostics JMD", "year": 2013 }, { "abstract": "Data stream management systems (DSMSs) are scalable, highly available, and fault tolerant systems that aggregate and analyze real time data in motion. To continuously perform analytics on the fly within the stream, state of the art DSMSs host streaming applications as a set of interconnected operators, with each operator encapsulating the semantic of a specific operation. For parallel execution on a particular platform, these operators need to be appropriately replicated in multiple instances that split and process the workload simultaneously. Because the way operators are partitioned affects the resulting performance of streaming applications, it is essential for DSMSs to have a method to compare different operators and make holistic replication decisions to avoid performance bottlenecks and resource wastage. To this end, we propose a stepwise profiling approach to optimize application performance on a given execution platform. It automatically scales distributed computations over streams based on application features and processing power of provisioned resources and builds the relationship between provisioned resources and application performance metrics to evaluate the efficiency of the resulting configuration. Experimental results confirm that the proposed approach successfully fulfills its goals with minimal profiling overhead.", "author_names": [ "Xunyun Liu", "Amir Vahid Dastjerdi", "Rodrigo Neves Calheiros", "Chenhao Qu", "Rajkumar Buyya" ], "corpus_id": 26245600, "doc_id": "26245600", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "A Stepwise Auto Profiling Method for Performance Optimization of Streaming Applications", "venue": "ACM Trans. Auton. Adapt. Syst.", "year": 2018 }, { "abstract": "Abstract Typically, the execution time of a kernel on a GPU is a difficult to predict measure as it depends on a wide range of factors. Performance can be limited by either memory transfer, compute throughput or other latencies. In this paper, we improve on the roofline model following a quantitative approach and present a completely automated GPU performance prediction technique. In this respect this model utilizes micro benchmarking and profiling in a \"black box\" fashion as no inspection of source/binary code is required. The proposed model combines parameters in order to characterize the performance limiting factor and to estimate execution time. In addition, we propose the quadrant split visual representation, which captures the characteristics of multiple processors in relation to a particular kernel. We performed experiments on stencil computation (red/black SOR) SGEMM and a total of 28 kernels of the Rodinia benchmark suite, using six CUDA GPUs and we showed an absolute error in predictions of 27.66% in the average case. Furthermore, the performance model was also examined on an AMD GPU through the HIP programming environment. Prediction errors were comparable despite the significant architectural differences between different vendor GPUs.", "author_names": [ "Elias Konstantinidis", "Yannis Cotronis" ], "corpus_id": 42443917, "doc_id": "42443917", "n_citations": 25, "n_key_citations": 0, "score": 1, "title": "A quantitative roofline model for GPU kernel performance estimation using micro benchmarks and hardware metric profiling", "venue": "J. Parallel Distributed Comput.", "year": 2017 }, { "abstract": "Bile acids are important end products of cholesterol metabolism. While they have been identified as key factors in lipid emulsification and absorption due to their detergent properties, bile acids have also been shown to act as signaling molecules and intermediates between the host and the gut microbiota. To further the investigation of bile acid functions in humans, an advanced platform for high throughput analysis is essential. Herein, we describe the development and application of a 15 min UPLC procedure for the separation of bile acid species from human biofluid samples requiring minimal sample preparation. High resolution time of flight mass spectrometry was applied for profiling applications, elucidating rich bile acid profiles in both normal and disease state plasma. In parallel, a second mode of detection was developed utilizing tandem mass spectrometry for sensitive and quantitative targeted analysis of 145 bile acid (BA) species including primary, secondary, and tertiary bile acids. The latter system was validated by testing the linearity (lower limit of quantification, LLOQ, 0.25 10 nM and upper limit of quantification, ULOQ, 2.5 5 mM) precision (6.5% and accuracy (81.2 118.9% on inter and intraday analysis achieving good recovery of bile acids (serum/plasma 88% and urine 93% The ultra performance liquid chromatography mass spectrometry (UPLC MS)/MS targeted method was successfully applied to plasma, serum, and urine samples in order to compare the bile acid pool compositional difference between preprandial and postprandial states, demonstrating the utility of such analysis on human biofluids.", "author_names": [ "Magali H Sarafian", "Matthew R Lewis", "Alexandros Pechlivanis", "Simon J L Ralphs", "Mark J Mcphail", "Vishal C Patel", "Marc-Emmanuel Dumas", "Elaine Holmes", "Jeremy K Nicholson" ], "corpus_id": 3158392, "doc_id": "3158392", "n_citations": 120, "n_key_citations": 1, "score": 0, "title": "Bile acid profiling and quantification in biofluids using ultra performance liquid chromatography tandem mass spectrometry.", "venue": "Analytical chemistry", "year": 2015 }, { "abstract": "MPI functions in the large scale object oriented finite element software were overloaded to carry out user defined parallel performance profiling.Log functions in Multi Processing Environment(MPE) library were inserted to MPI functions when the MPI functions were overloaded.A typical impact simulation has been carried out using 16 CPUs,and the simulation process was monitored.Parallel finite element algorithm which was used in the simulation has been evaluated by analyzing the monitor results.", "author_names": [ "Wang Hai-bing" ], "corpus_id": 63340166, "doc_id": "63340166", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Parallel performance profile of large scale object oriented finite element software", "venue": "", "year": 2011 }, { "abstract": "The paper describes a post mortem call graph profiling tool that analyses trace information generated during the execution of BSPlib programs. The purpose of the tool is to expose imbalance in either computation or communication, and to highlight portions of code that are amenable to improvement. Unlike other profiling tools, the profile information guides optimisation in an architecture independent way. From an ease of use perspective, the amount of information displayed when visualising a profile for a parallel program is no more complex than that of a sequential program.", "author_names": [ "Jonathan M D Hill", "Stephen A Jarvis", "Constantinos J Siniolakis", "Vasil P Vasilev" ], "corpus_id": 15142701, "doc_id": "15142701", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Portable and architecture independent parallel performance tuning using a call graph profiling tool", "venue": "Proceedings of the Sixth Euromicro Workshop on Parallel and Distributed Processing PDP '98", "year": 1998 }, { "abstract": "A wide variety of large scale data have been produced in bioinformatics. In response, the need for efficient handling of biomedical big data has been partly met by parallel computing. However, the time demand of many bioinformatics programs still remains high for large scale practical uses because of factors that hinder acceleration by parallelization. Recently, new generations of storage devices have emerged, such as NAND flash based solid state drives (SSDs) and with the renewed interest in near data processing, they are increasingly becoming acceleration methods that can accompany parallel processing. In certain cases, a simple drop in replacement of hard disk drives by SSDs results in dramatic speedup. Despite the various advantages and continuous cost reduction of SSDs, there has been little review of SSD based profiling and performance exploration of important but time consuming bioinformatics programs. For an informative review, we perform in depth profiling and analysis of 23 key bioinformatics programs using multiple types of devices. Based on the insight we obtain from this research, we further discuss issues related to design and optimize bioinformatics algorithms and pipelines to fully exploit SSDs. The programs we profile cover traditional and emerging areas of importance, such as alignment, assembly, mapping, expression analysis, variant calling and metagenomics. We explain how acceleration by parallelization can be combined with SSDs for improved performance and also how using SSDs can expedite important bioinformatics pipelines, such as variant calling by the Genome Analysis Toolkit and transcriptome analysis using RNA sequencing. We hope that this review can provide useful directions and tips to accompany future bioinformatics algorithm design procedures that properly consider new generations of powerful storage devices.", "author_names": [ "Sungmin Lee", "Hyeyoung Min", "Sungroh Yoon" ], "corpus_id": 3910274, "doc_id": "3910274", "n_citations": 10, "n_key_citations": 1, "score": 0, "title": "Will solid state drives accelerate your bioinformatics? In depth profiling, performance analysis and beyond", "venue": "Briefings Bioinform.", "year": 2016 }, { "abstract": "The PMLS parallelizing compiler for Standard ML is based upon the automatic instantiation of algorithmic skeletons at sites of higher order function (HOF) use. Rather than mechanically replacing HOFs with skeletons, which in general leads to poor parallel performance, PMLS seeks to predict run time parallel behaviour to optimise skeleton use. Static extraction of analytic cost models from programs is undecidable, and practical heuristic approaches are intractable. In contrast, PMLS utilises a hybrid approach by combining static analytic cost models for skeletons with dynamic information gathered from the sequential instrumentation of HOF argument functions. Such instrumentation is provided by an implementation independent SML interpreter, based on the language's Structural Operational Semantics (SOS) in the form of SOS rule counts. PMLS then tries to relate the rule counts to program execution times through numerical techniques. This paper considers the design and implementation of the PMLS approach to parallel performance prediction. The formulation of a general rule count cost model as a set of over determined linear equations is discussed, and their solution by single value decomposition, and by a genetic algorithm, are presented.", "author_names": [ "Norman Scaife", "Greg J Michaelson", "Susumu Horiguchi" ], "corpus_id": 61088491, "doc_id": "61088491", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Empirical Parallel Performance Prediction From Semantics Based Profiling", "venue": "", "year": 2001 }, { "abstract": "Large scale human microbiota studies require specimens collected from multiple sites and/or time points to maximize detection of the small effects in microbe host interactions. However, batch biases caused by experimental protocols, such as sample collection, massively parallel sequencing, and bioinformatics analyses, remain critical and should be minimized. This work evaluated the effects of preservation solutions and bacterial 16S rRNA gene primer pairs in revealing human gut microbiota composition. Since notable changes in detecting bacterial composition and abundance were observed among choice of preservatives and primer pairs, a consistent methodology is essential in minimizing their effects to facilitate comparisons between data sets. ABSTRACT Proper preservation of stool samples to minimize microbial community shifts and inactivate infectious agents is important for self collected specimens requiring shipment to laboratories when cold chain transport is not feasible. In this study, we evaluated the performance of six preservation solutions (Norgen, OMNI, RNAlater, CURNA, HEMA, and Shield) for these aspects. Following storage of human stool samples with these preservatives at room temperature for 7 days, three hypervariable regions of the bacterial 16S rRNA gene (V1 V2, V3 V4, and V4) were amplicon sequenced. We found that samples collected in two preservatives, Norgen and OMNI, showed the least shift in community composition relative to 80degC standards compared with other storage conditions, and both efficiently inhibited the growth of aerobic and anaerobic bacteria. RNAlater did not prevent bacterial activity and exhibited relatively larger community shift. Although the effect of preservation solution was small compared to intersubject variation, notable changes in microbiota composition were observed, which could create biases in downstream data analysis. When community profiles inferred from different 16S rRNA gene hypervariable regions were compared, we found differential sensitivity of primer sets in identifying overall microbial community and certain bacterial taxa. For example, reads generated by the V4 primer pair showed a higher alpha diversity of the gut microbial community. The degenerate 27f YM primer failed to detect the majority of Bifidobacteriales. Our data indicate that choice of preservation solution and 16S rRNA gene primer pair are critical determinants affecting gut microbiota profiling. IMPORTANCE Large scale human microbiota studies require specimens collected from multiple sites and/or time points to maximize detection of the small effects in microbe host interactions. However, batch biases caused by experimental protocols, such as sample collection, massively parallel sequencing, and bioinformatics analyses, remain critical and should be minimized. This work evaluated the effects of preservation solutions and bacterial 16S rRNA gene primer pairs in revealing human gut microbiota composition. Since notable changes in detecting bacterial composition and abundance were observed among choice of preservatives and primer pairs, a consistent methodology is essential in minimizing their effects to facilitate comparisons between data sets.", "author_names": [ "Zigui Chen", "Pak Chun Hui", "Mamie Hui", "Yun Kit Yeoh", "Po Yee Wong", "Martin Chi-Wai Chan", "Martin C S Wong", "Siew Chien Ng", "Francis K L Chan", "Paul K S Chan" ], "corpus_id": 67862172, "doc_id": "67862172", "n_citations": 50, "n_key_citations": 3, "score": 0, "title": "Impact of Preservation Method and 16S rRNA Hypervariable Region on Gut Microbiota Profiling", "venue": "mSystems", "year": 2019 }, { "abstract": "This paper presents the latest chapter in our adventures coping with a large, sequentially tuned, legacy runtime system in today's parallel world. Specifically, this paper introduces our new graphical visualizer that helps programmers understand how to program in parallel with Racket's futures and, to some extent, what performs well in sequential Racket. Overall, our experience with parallelism in Racket is that we can achieve reasonable parallel performance in Racket without sacrificing the most important property of functional programming language implementations, namely safety. That is, Racket programmers are guaranteed that every Racket primitive (and thus all functions built using Racket primitives) will either behave properly, or it will signal an error explaining what went wrong. That said, however, it is challenging to understand how to best use futures to achieve interesting speedups, and the visualizer is our attempt to more widely disseminate key performance details of the runtime system in order to help Racket programmers maximize performance.", "author_names": [ "James Swaine", "Burke Fetscher", "Vincent St-Amour", "Robert Bruce Findler", "Matthew Flatt" ], "corpus_id": 13977816, "doc_id": "13977816", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Seeing the futures: profiling shared memory parallel racket", "venue": "FHPC '12", "year": 2012 } ]

[ { "abstract": "1 Problems of the Energy Economy 2 Photons 3 Semiconductors 4 Conversion of Thermal Radiation into Chemical Energy 5 Conversion of Chemical Energy into Electrical Energy 6 Basic Structure of Solar Cells 7 Limitations on Energy Conversion in Solar Cells 8 Concepts for Improving the Efficiency of Solar Cells 9 Prospects for the Future", "author_names": [ "Peter Prof Dr Wurfel", "Uli Wurfel" ], "corpus_id": 118107056, "doc_id": "118107056", "n_citations": 406, "n_key_citations": 26, "score": 1, "title": "Physics of solar cells from basic principles to advanced concepts", "venue": "", "year": 2009 }, { "abstract": "List of Symbols.Preface.1 Problems of the Energy Economy.1.1 Energy economy.1.2 Estimate of the maximum reserves of fossil energy.1.3 The greenhouse effect.2 Photons.2.1 Black body radiation.2.2 Kirchhoff's law of radiation for non black bodies.2.3 The solar spectrum.2.4 Concentration of the solar radiation.2.5 Maximum efficiency of solar energy conversion.3 Semiconductors.3.1 Electrons in semiconductors.3.2 Holes.3.3 Doping.3.4 Quasi Fermi distributions.3.5 Generation of electrons and holes.3.6 Recombination of electrons and holes.3.7 Light emission by semiconductors.4 Conversion of Thermal Radiation into Chemical Energy.4.1 Maximum efficiency for the production of chemical energy.5 Conversion of Chemical Energy into Electrical Energy.5.1 Transport of electrons and holes.5.2 Separation of electrons and holes.5.3 Diffusion length of minority carriers.5.4 Dielectric relaxation.5.5 Ambipolar diffusion.5.6 Dember effect.5.7 Mathematical description.6 Basic Structure of Solar Cells.6.1 A chemical solar cell.6.2 Basic mechanisms in solar cells.6.3 Dye solar cell.6.4 The pn junction.6.5 pn junction with impurity recombination, two diode model.6.6 Hetero junctions.6.7 Semiconductor metal contact.6.8 The role of the electric field in solar cells.7 Limitations on Energy Conversion in Solar Cells.7.1 Maximum efficiency of solar cells.7.2 Efficiency of solar cells as a function of their energy gap.7.3 The optimal silicon solar cell.7.4 Thin film solar cells.7.5 Equivalent circuit.7.6 Temperature dependence of the open circuit voltage.7.7 Intensity dependence of the efficiency.7.8 Efficiencies of the individual energy conversion processes.8 Concepts for Improving the Efficiency of Solar Cells.8.1 Tandem cells.8.2 Concentrator cells.8.3 Thermo photovoltaic energy conversion.8.4 Impact ionization.8.5 Two step excitation in three level systems.9 Prospects for the Future.Appendix.Index.", "author_names": [ "Peter Prof Dr Wurfel" ], "corpus_id": 116944127, "doc_id": "116944127", "n_citations": 400, "n_key_citations": 22, "score": 0, "title": "Physics of solar cells from principles to new concepts", "venue": "", "year": 2005 }, { "abstract": "", "author_names": [ "Peter Prof Dr Wurfel" ], "corpus_id": 124495765, "doc_id": "124495765", "n_citations": 390, "n_key_citations": 22, "score": 0, "title": "Physics of solar cells", "venue": "", "year": 2005 }, { "abstract": "The selective transport of electrons and holes to the two terminals of a solar cell is often attributed to an electric field, although well known physics states that they are driven by gradients of quasi Fermi energies. However, in an illuminated semiconductor, these forces are not selective, and they drive both charge carriers toward both contacts. This paper shows that the necessary selectivity is achieved by differences in the conductivities of electrons and holes in two distinct regions of the device, which, for one charge carrier, allows transport to one contact and block transport to the other contact.", "author_names": [ "Uli Wurfel", "Andres Cuevas", "Peter Wurfel" ], "corpus_id": 32080590, "doc_id": "32080590", "n_citations": 229, "n_key_citations": 5, "score": 0, "title": "Charge Carrier Separation in Solar Cells", "venue": "IEEE Journal of Photovoltaics", "year": 2015 }, { "abstract": "Solar cells may become the most important option for the energy supply of mankind. It would certainly help if their efficiency could be raised substantially above the present value for commercial panels of 12 to 15% General thermodynamical arguments give much higher efficiency limits. In order to exploit them with solar cells, future concepts should be based only on necessary requirements. Present day solar cells are based on pn junctions and their understanding goes back to the beginnings of semiconductor device physics [1] It will be shown that pn junctions do not really belong to the necessary requirements. In addition, their understanding is at least misleading when applied to solar cells. In order to be able to find new concepts for more efficient solar cells, wrong ideas must be corrected. Since thermodynamics is independent of particular device aspects, it is particularly well suited to explore the limits of solar cells.", "author_names": [ "Peter Prof Dr Wurfel" ], "corpus_id": 61202391, "doc_id": "61202391", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Thermodynamics of Solar Cells", "venue": "", "year": 2004 }, { "abstract": "", "author_names": [ "Ghassan E Jabbour", "Evan Laurence Williams" ], "corpus_id": 137492246, "doc_id": "137492246", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book Review: Physics of Solar Cells. By Peter Wurfel.", "venue": "", "year": 2005 }, { "abstract": "Books reviewed: Physics of Solar Cells, 2nd Edition (Wurfel, P. 2009) Essentials of RF and Microwave Grounding (Holtzman, E. 2006) Polymer Tribology (Sinha, S. K. and Briscoe,B. J. 2009) PVC Degradation and Stabilization (Wypych, G. 2008) Advanced Batteries (Huggins, R. A. 2009) The Lineman's and Cableman's Field Manual, 2nd Edition (Shoemaker, T. M. and Mack, J. E. 2009) Lead Your Boss (Baldoni, J. 2009) Industrial Power Systems (Khan, S. 2008)", "author_names": [ "John J Shea" ], "corpus_id": 47378389, "doc_id": "47378389", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Book reviews [8 books reviewed]", "venue": "IEEE Electrical Insulation Magazine", "year": 2010 }, { "abstract": "Abstract Following the recent success of monolithically integrated Perovskite/Si tandem solar cells, great interest has been raised in searching for alternative wide bandgap top cell materials with prospects of a fully earth abundant, stable and efficient tandem solar cell. Thin film chalcogenides (TFCs) such as the Cu 2 ZnSnS 4 (CZTS) could be suitable top cell materials. However, TFCs have the disadvantage that generally at least one high temperature step 500 degC) is needed during the synthesis, which could contaminate the Si bottom cell. Here, we systematically investigate the monolithic integration of CZTS on a Si bottom solar cell. A thermally resilient double sided Tunnel Oxide Passivated Contact (TOPCon) structure is used as bottom cell. A thin 25 nm) TiN layer between the top and bottom cells, doubles as diffusion barrier and recombination layer. We show that TiN successfully mitigates in diffusion of CZTS elements into the c Si bulk during the high temperature sulfurization process, and find no evidence of electrically active deep Si bulk defects in samples protected by just 10 nm TiN. Post process minority carrier lifetime in Si exceeded 1.5 ms, i.e. a promising implied open circuit voltage (i V oc of 715 mV after the high temperature sulfurization. Based on these results, we demonstrate a first proof of concept two terminal CZTS/Si tandem device with an efficiency of 1.1% and a V oc of 900 mV. A general implication of this study is that the growth of complex semiconductors on Si using high temperature steps is technically feasible, and can potentially lead to efficient monolithically integrated two terminal tandem solar cells.", "author_names": [ "Alireza Hajijafarassar", "Filipe Martinho", "Fredrik Stulen", "Sigbjorn Grini", "Sim'on L'opez-Marino", "Moises Esp'indola-Rodr'iguez", "Max Dobeli", "Stela Canulescu", "Eugen Stamate", "Mungunshagai Gansukh", "Sara Engberg", "Andrea Crovetto", "Lasse Vines", "J Schou", "Ole Hansen Dtu Nanolab", "Technical University of Denmark", "Department of Electrical Engineering", "Technical Physics", "University of Oslo Ion Beam Physics", "Eth Zurich Dtu Physics" ], "corpus_id": 213055368, "doc_id": "213055368", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Monolithic thin film chalcogenide silicon tandem solar cells enabled by a diffusion barrier", "venue": "", "year": 2019 }, { "abstract": "The presence of interface recombination in a complex multilayered thin film solar structure causes a disparity between the internal open circuit voltage (VOC,in) measured by photoluminescence, and the external open circuit voltage (VOC,ex) i.e. an additional VOC deficit. Higher VOC,ex value aim require a comprehensive understanding of connection between VOC deficit and interface recombination. Here, a deep near surface defect model at the absorber/buffer interface is developed for copper indium di selenide solar cells grown under Cu excess conditions to explain the disparity between VOC,in and VOC,ex. The model is based on experimental analysis of", "author_names": [ "Mohit Sood", "Aleksander Urbaniak", "Christian Kameni Boumenou", "Thomas Paul Weiss", "Hossam Elanzeery", "Finn Babbe", "Florian Werner", "Michele Melchiorre", "Susanne Siebentritt Department of Physics", "Materials Science", "University of Luxembourg", "", "Luxembourg Faculty of Physics", "Warsaw University of Technology", "79 Koszykowa", "Warszawa 00-662", "Poland Chemical Sciences Division", "Joint Center for Artificial Photosynthesis", "Lawrence Berkeley National Laboratory", "Usa Hydrosat", "rue du Laboratoire", "L-1911 Luxembourg" ], "corpus_id": 232404764, "doc_id": "232404764", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Near surface defects: Cause of deficit between internal and external open circuit voltage in solar cells", "venue": "", "year": 2021 }, { "abstract": "Empirical data for the fill factor as a function of charge carrier mobility for two different polymer:fullerene systems is presented and analyzed. The results indicate that charge extraction depth limitations and space charge effects are inconsistent with the observed behavior, and the decrease in the fill factor is, instead, attributed to the field dependent charge separation and geminate recombination. A solar cell photocurrent limited by the Onsager Braun charge transfer exciton dissociation is shown to be able to accommodate the experimental observations. Charge dissociation limited solar cells always benefit from increased mobilities, and the negative contribution from the reduced charge separation is shown to be much more important for the fill factor in these material systems than any adverse effects from charge carrier extraction depth limitations or space charge effects due to unbalanced mobilities. The logarithmic dependence of the fill factor on the mobility for such a process is also shown to imply that simply increasing the mobilities is an impractical way to reach very high fill factors under these conditions since unrealistically high mobilities are required. A more controlled morphology is, instead, argued to be necessary for high performance. V C 2011 American Institute of Physics. [doi:10.1063/1.3609079]", "author_names": [ "Lars Mattias Andersson", "Christian Muller", "Bekele H Badada", "Fengling Zhang", "Uli Wurfel", "Olle Inganas" ], "corpus_id": 18330319, "doc_id": "18330319", "n_citations": 54, "n_key_citations": 0, "score": 0, "title": "Mobility and fill factor correlation in geminate recombination limited solar cells", "venue": "", "year": 2011 } ]

[ { "abstract": "In this paper, a 1T DRAM based on the junctionless field effect transistor (JLFET) with an ultrathin polycrystalline silicon layer was designed and investigated by using technology computer aided design simulation (TCAD) The application of a negative voltage at the control gate results in the generation of holes in the storage region by the band to band tunneling (BTBT) effect. Memory characteristics such as sensing margin and retention time are affected by the doping concentration of the storage region, bias condition of the program, and length of the intrinsic region. In addition, the gate acts as a switch that controls the transfer characteristics while the control gate plays a role in retaining holes in the hold state. The device was optimized, considering various parameters such as the doping concentration of the storage region (Nstorage) intrinsic region length (Lint) and operation bias conditions to obtain a high sensing margin of 49.7 mA/mm and a long retention time of 2 s even at a high temperature of 358 K. The obtained retention time is almost 30 times longer than that predicted for modern DRAM cells by the International technology roadmap for semiconductors (ITRS)", "author_names": [ "Min Su Cho", "Jun Hyeok Jung", "Won Douk Jang", "Hye Jin Mun", "Jaewon Jang", "Jin-Hyuk Bae", "In Man Kang" ], "corpus_id": 232229702, "doc_id": "232229702", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Design of a Capacitorless Dynamic Random Access Memory Based on Ultra Thin Polycrystalline Silicon Junctionless Field Effect Transistor with Dual Gate.", "venue": "Journal of nanoscience and nanotechnology", "year": 2021 }, { "abstract": "Abstract This work reports the realization of high performance n type random network single walled carbon nanotube (rn SWCNT) field effect transistor (FET) by means of contact engineering, where a low work function metal, Yttrium (Y) is used as the source and drain contacts. The presence of crossed metallic m and semiconducting s SWCNT junctions in the channel of rn SWCNT FETs, which form p type rectifying Schottky barrier, is believed to introduce non negligible hole current in the fabricated FETs and lead to undesirable ambipolar characteristic. By means of soaking in 2,4,6 triphenylpyrylium tetrafluoroborate (2,4,6 TPPT) we have successfully converted the ambipolar rn SWCNT FETs to highly unipolar n type devices by selectively removing the m SWCNTs in the FET channel. The best characteristics of our unipolar n type rn SWCNT FETs are as follows: on/off current ratio up to ~10 5 mobility as high as 25 cm 2 V 1 s 1 and transconductance of 0.12 mS/mm; they have demonstrated air stable n type characteristics and are also more reproducibility than individual SWCNT FETs.", "author_names": [ "Lei Huang", "Eng Fong Chor", "Yihong Wu" ], "corpus_id": 108462673, "doc_id": "108462673", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Doping free fabrication of n type random network single walled carbon nanotube field effect transistor with yttrium contacts", "venue": "", "year": 2011 }, { "abstract": "Using calibrated simulations, we report a detailed study of the doping less tunnel field effect transistor (TFET) on a thin intrinsic silicon film using charge plasma concept. Without the need for any doping, the source and drain regions are formed using the charge plasma concept by choosing appropriate work functions for the source and drain metal electrodes. Our results show that the performance of the doping less TFET is similar to that of a corresponding doped TFET. The doping less TFET is expected to be free from problems associated with random dopant fluctuations. Furthermore, fabrication of doping less TFET does not require a high temperature doping/annealing processes and therefore cuts down the thermal budget, opening up possibilities for fabricating TFETs on single crystal silicon on glass substrates formed by wafer scale epitaxial transfer.", "author_names": [ "Mamidala Jagadesh Kumar", "S Janardhanan" ], "corpus_id": 16539744, "doc_id": "16539744", "n_citations": 374, "n_key_citations": 24, "score": 1, "title": "Doping Less Tunnel Field Effect Transistor: Design and Investigation", "venue": "IEEE Transactions on Electron Devices", "year": 2013 }, { "abstract": "This work investigates the novel device structure, silicon on nothing electrostatically doped junctionless tunnel field effect transistor (SON ED JLTFET) with high K stacked hetero gate technology for its short channel effects (SCEs) immune properties. Here, its analog/RF device performance metrices are also analyzed using calibrated 2 D technology computer aided design (TCAD) simulation study. This device is expected to exhibit the fundamental advantages of SON technology, i.e. it should be more immune towards SCEs, like threshold voltage roll off, drain induced barrier lowering (DIBL) even for devices with less than 10 nm channel length. Moreover, owing to its electrostatic doping instead of metallurgical doping, the detrimental doping control issues, such as mobility degradation, higher fabrication thermal budget and statistical random dopant fluctuations (RDFs) can no more degrade the device performance. This helps in realization of more process variations immune design. Here the detailed device sensitivity analysis with respect to the various crucial devices dimensional parameters variation is also carried out.", "author_names": [ "Aishwarya Kaity", "Sangeeta Singh", "Pravin Neminath Kondekar" ], "corpus_id": 212581386, "doc_id": "212581386", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Silicon On Nothing Electrostatically Doped Junctionless Tunnel Field Effect Transistor (SON ED JLTFET) A Short Channel Effect Resilient Design", "venue": "Silicon", "year": 2020 }, { "abstract": "Recently, dopingless tunnel FET (DL TFET) has emerged and gathered much attention, for it avoids the physical doping process and provides superior immunity against random dopant fluctuation. Nevertheless, it also suffers from low drive current and severe ambipolar effect. In order to overcome these problems, an L shaped DL TFET (LDL TFET) with the gate engineering technique is proposed in this paper. In this device, the space between the source and the gate electrodes can be further optimized to reduce the tunneling distance, and hence boost the drive current. Also, without much fabrication difficulties, hetero gate dielectric (HGD) and tunneling gate (TG) structures can be utilized in the LDL TFET. Benefiting from the modification of the band energy by HGD and TG, the source channel tunneling distance is further reduced, while the drain channel tunneling distance is enlarged. TCAD simulation results show that in comparison with planar DL TFET (PDL TFET) LDL TFET offers better performance in terms of on current, switch ratio, subthreshold slope, ambipolar current and RF parameters. It indicates that the LDL TFET is a promising device for low power RF and digital logic applications.", "author_names": [ "Cong Li", "Jia-min Guo", "Hao-Feng Jiang", "Hailong You", "Weifeng Liu", "Yiqi Zhuang" ], "corpus_id": 219466386, "doc_id": "219466386", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A novel gate engineered L shaped dopingless tunnel field effect transistor", "venue": "", "year": 2020 }, { "abstract": "In this paper, a Gate stack Doping less Tunnel field effect transistor is proposed using a double gate doping less TFET(DLTFET) with a multilayer gate stack architecture. The device characteristics are demonstrated and compared with DLTFET. It is found that the proposed architecture is having better performance than DLTFET. It is based on Charge plasma concept. There is no Source and Drain doping applied. Thus, it is free from Random dopant fluctuation issue and highly reliable. The gate dielectrics are used in stack manner to form a multilayer architecture. It provides the ON current of about 0.1 mA/um with a low OFF current, 5x10 18 A/um. The threshold voltage is 0.8V and the Sub threshold swing is calculated as 77mV/dec. All the simulations has been performed using SILVACO ATLAS device simulator.", "author_names": [ "Deepali Vasnik" ], "corpus_id": 59576193, "doc_id": "59576193", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "DESIGN AND ANALYSIS OF GATE STACK DOPING LESS TUNNEL FIELD EFFECT TRANSISTOR", "venue": "", "year": 2014 }, { "abstract": "In this work, we explore for the first time dual material gate (DMG) and inverse DMG devices for suppressing the random dopant (RD) induced characteristic fluctuation in 16 nm metal oxide semiconductor field effect transistor (MOSFET) devices. The physical mechanism of suppressing the characteristic fluctuation of DMG devices is observed and discussed. The achieved improvement in suppressing the RD induced threshold voltage, on state current, and off state current fluctuations are 28, 12.3, and 59% respectively. To further suppress the fluctuations, an approach that combines the DMG method and channel doping profile engineering is also advanced and explored. The results of our study show that among the suppression techniques, the use of the DMG device with an inverse lateral asymmetric channel doping profile has good immunity to fluctuation.", "author_names": [ "Yiming Li", "Kuo-Fu Lee", "Chun-Yen Yiu", "Yung-Yueh Chiu", "R W Chang" ], "corpus_id": 54891255, "doc_id": "54891255", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Dual Material Gate Approach to Suppression of Random Dopant Induced Characteristic Fluctuation in 16 nm Metal Oxide Semiconductor Field Effect Transistor Devices", "venue": "", "year": 2011 }, { "abstract": "Abstract In this paper, for the first time, DC characteristics and analog/RF performance of polarity control GaAs Ge hetero TFET (GaAs Ge H TFET) structure have been analysed, using electrically doped dynamically configurable concept. For this, we have considered a hetero structure with two distinctive gates (Control gate and Polarity gate) Polarity gate induces p+ region at the source side and n+ region at the drain side, instead of relying on the abrupt doping profile at the junctions. Therefore, the fabrication process of the proposed device avoids ion implantation, photo masking and complicated thermal budget. Hence, it shows high immunity against process variations, doping control issues and random dopant fluctuations (RDF) In order to optimize the device performance, interfacing of III V groups materials with IV group semiconductor is done for hetero junction. The introduction of hetero junction and band gap engineering offer higher ION/IOFF ratio (5.1 x 1012) steep sub threshold slope (18 mV/decade) and significantly change in analog/RF performance. The analog/RF figures of merit are analysed in term of transconductance (gm) output conductance (gds) gate to source capacitance (Cgs) gate to drain capacitance (Cgd) cutoff frequency (fT) and gain bandwidth (GBW) product. The proposed work would be beneficial for low power high frequency applications. The simulation results presented in this paper were carried out by using 2 D ATLAS.", "author_names": [ "Kaushal Nigam", "Pravin Neminath Kondekar", "Dheeraj Sharma" ], "corpus_id": 112308064, "doc_id": "112308064", "n_citations": 40, "n_key_citations": 3, "score": 0, "title": "DC characteristics and analog/RF performance of novel polarity control GaAs Ge based tunnel field effect transistor", "venue": "", "year": 2016 }, { "abstract": "A novel dual metal gate doping less vertical tunnel field effect transistor (D VTFET) on silicon body, using work function engineering is proposed. The proposed structure does not required impurity doping for formation of the drain and the source regions. In this concern, source and drain regions are formed by selecting appropriate work function of metal electrode. The source and drain regions are not formed by conventional ways of ion implantation or diffusion. Hence, proposed structure is immune greatly to the process variation, issues of doping control and random dopant fluctuations which are serious problems in ultrathin silicon devices. For further improvement in ON state current and analogue/RF figures of merit dual work function of single gate material is considered. The electrical characteristics of the proposed device with the D VTFET are simulated and compared.", "author_names": [ "Kaushal Nigam", "Pravin Neminath Kondekar", "Dheeraj Sharma" ], "corpus_id": 112831979, "doc_id": "112831979", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "High frequency performance of dual metal gate vertical tunnel field effect transistor based on work function engineering", "venue": "", "year": 2016 }, { "abstract": "Silicon based Static Random Access Memory (SRAM) has not been keeping pace with technology trends due to the limited improvements in power, performance and density. This paper explores graphene based SRAM as a potential replacement of silicon SRAM for future digital electronics. Due to its higher current on to off ratio, the graphene nanoribbon field effect transistor (GNRFET) has been considered in this paper. In the nanometer regime, process variation is not only inevitable but also very pronounced. To mitigate its effects as much as possible, the Schottky Barrier type GNRFET is considered which presents lower variation in its characteristics due to doping variation. The results show that graphene nanoribbon has a great potential in digital circuit design. The GNRFET based SRAM design presented in this paper leads to significantly lower power consumption, approximately 93% compared to 45 nm silicon technology. This upper bound can be quite achievable as the fabrication technology of graphene reaches maturity.", "author_names": [ "Shital Joshi", "Saraju P Mohanty", "Elias Kougianos", "Venkata P Yanambaka" ], "corpus_id": 15039217, "doc_id": "15039217", "n_citations": 13, "n_key_citations": 2, "score": 0, "title": "Graphene Nanoribbon Field Effect Transistor Based Ultra Low Energy SRAM Design", "venue": "2016 IEEE International Symposium on Nanoelectronic and Information Systems (iNIS)", "year": 2016 } ]

[ { "abstract": "Diamond thin films represent a class of multi functional materials whose morphological, chemical, optical and electronic properties can be tailored on demand for specific applications. Nevertheless, this material's versatility inherently requires a high degree of control and understanding of the diamond growth technology. Here, especially, processes at low temperatures become important because of physical limitations regarding the intrinsic properties of typical target substrates (i.e. low melting temperature, high expansion coefficient, high thermal diffusion and chemical reactivity) and compatibility with standard semiconductor industrial technologies. However, low temperature diamond growth (LTDG) is still highly challenging, where novel phenomena are encountered that still remain to be understood. The present chapter focuses on low temperature diamond growth from technological and practical points of view. The LTDG process is divided in two strategies, which are based on i) the modification of the deposition systems and ii) the change of gas chemistry. The state of the art of each strategy and the fundamental growth processes that are involved are reviewed. Among the discussed diamond growth processes, microwave surface wave plasma in linear antenna configuration with oxygen containing gas mixtures is shown as the most promising process for LTDG over large areas with high optical and electronic grade materials. The growth phenomena observed in linear antenna microwave plasma provide a simple way to control nano and poly crystalline diamond character. A practical comparison between focused and linear antenna microwave plasma is presented on several key studies, which utilize LTDG on amorphous silicon, glass, germanium and optical elements used for IR spectroscopy.", "author_names": [ "T Izak", "Oleg Babchenko", "Stepan Potocky", "Zdenek Remes", "Halyna Kozak", "Elisseos Verveniotis", "Bohuslav Rezek", "Alexander Kromka" ], "corpus_id": 138870278, "doc_id": "138870278", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "CHAPTER 13:Low Temperature Diamond Growth", "venue": "", "year": 2014 }, { "abstract": "Recently, there is a great effort to increase the deposition area and decrease the process temperature for diamond growth which will enlarge its applications including use of temperature sensitive substrates. In this work, we report on the large area (20 x 30 cm2) and low temperature (250 degC) polycrystalline diamond growth by pulsed linear antenna microwave plasma system. The influence of substrate temperature varied from 250 to 680 degC, as controlled by the table heater and/or by microwave power, is studied. It was found that the growth rate, film morphology and diamond to non diamond phases (sp3/sp2 carbon bonds) are influenced by the growth temperature, as confirmed by SEM and Raman measurements. The surface chemistry and growth processes were studied in terms of activation energies (Ea) calculated from Arrhenius plots. The activation energies of growth processes were very low (1.7 and 7.8 kcal mol 1) indicating an energetically favourable growth process from the CO2CH4H2 gas mixture. In addition, from activation energies two different growth regimes were observed at low and high temperatures, indicating different growth mechanism.", "author_names": [ "T Izak", "Oleg Babchenko", "Marian Varga", "Stepan Potocky", "Alexander Kromka" ], "corpus_id": 122981259, "doc_id": "122981259", "n_citations": 37, "n_key_citations": 1, "score": 1, "title": "Low temperature diamond growth by linear antenna plasma CVD over large area", "venue": "", "year": 2012 }, { "abstract": "Laser excited N and R fluorescence lines of heavily doped ruby have been studied up to 26 GPa at low temperatures. While the intensity of the R lines at ambient pressure significantly decreases with decreasing temperature, the intensity of N lines originating from exchange coupled Cr ion pairs is enhanced at low temperatures. The pressure induced wavelength shift of the N lines at 19 K is well fitted with an empirical formula similar to the equation for the R1 line, showing that the intense N line could be used as an alternative pressure scale at low temperatures. We also observe continuous increase in non hydrostaticity with increasing pressure at low temperatures when silicone oil and 4:1 mixture of methanol and ethanol are used as pressure media.", "author_names": [ "Hitoshi Yamaoka", "Yumiko Zekko", "Ignace Jarrige", "Jung-Fu Lin", "Nozomu Hiraoka", "Hirofumi Ishii", "K-D Tsuei", "Jun'ichiro Mizuki" ], "corpus_id": 17900089, "doc_id": "17900089", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Ruby pressure scale in a low temperature diamond anvil cell", "venue": "", "year": 2012 }, { "abstract": "The deposition of low energy carbon atoms onto a low temperature diamond (111) surface is studied by molecular dynamics computer simulations. A Stillinger Weber potential [F. H. Stillinger and T. A. Weber, Phys. Rev. B 31, 5262 (1985) with a reparametrization derived from quantum mechanical energy calculations for small tetrahedral carbon clusters, is used to model the interatomic interactions. The penetration of 1 100 eV neutral carbon atoms into the diamond (111) surface at 100 K and the resultant surface atom rearrangements and induced film stress are studied. For intermediate energies (20 60 eV) the incident atom penetrates beneath the exposed (111) surface and significantly increases the lateral compressive stress in the diamond film. The emerging picture is that diamond films grow from below the exposed surface in a region of locally high stress and tetrahedral coordination.", "author_names": [ "Bernard A Pailthorpe" ], "corpus_id": 96841239, "doc_id": "96841239", "n_citations": 42, "n_key_citations": 0, "score": 0, "title": "Molecular dynamics simulations of atomic processes at the low temperature diamond (111) surface", "venue": "", "year": 1991 }, { "abstract": "Thin diamond films were deposited on silicon, MgO, fused silica, and soda lime silica glass at low temperature (the lowest temperature ~365 degC) by microwave plasma enhanced chemical vapor deposition. The films were identified as diamond by Raman spectroscopy. A Raman peak shift of several wave numbers to either lower or higher wave numbers due to the strain of the film is also observed. The film deposited on glass is highly transparent. The fine faceted crystals in the film are shown in scanning electron microscope micrographs.", "author_names": [ "Yu-Chen Liou", "Aharon Inspektor", "Ronald A Weimer", "Russell Messier" ], "corpus_id": 120422147, "doc_id": "120422147", "n_citations": 90, "n_key_citations": 0, "score": 0, "title": "Low temperature diamond deposition by microwave plasma enhanced chemical vapor deposition", "venue": "", "year": 1989 }, { "abstract": "Preliminary studies have shown that diamond like carbon (DLC) coatings can be adherent on a range of substrate materials, resistant to wear and non toxic to cells in vitro. This has led to the question of the possible biomedical application of DLC coated materials, particularly in the field of implantation surgery. Assessment of the biocompatibility of implanted material requires two questions to be addressed: (1) is the implanted material toxic to cell growth, and (2) what is the nature of the cell DLC layer interaction? In this study we show, by the Kenacid Blue cytotoxicity test, that cells grown on DLC coated PCF membranes exhibit an initial increased attachment to the carbon substrate, and thereafter exhibit a normal growth rate over the 3 day test periods compared with cells grown on uncoated polystyrene. Scanning electron microscopy shows these cells possess characteristics typical of normal cell attachment and growth. Cells were grown on DLC coated PCF membranes to facilitate examination of the cell DLC coating interface by transmission electron microscopy. These results show that cells grown on both DLC coated and non coated membranes presented normal morphological characteristics of attachment and growth. These findings indicate that the DLC coating is non toxic in vitro and sustains normal cell growth.", "author_names": [ "T L Parker", "K L Parker", "I R McColl", "David M Grant", "John Vivian Wood" ], "corpus_id": 137572503, "doc_id": "137572503", "n_citations": 47, "n_key_citations": 1, "score": 0, "title": "The biocompatibility of low temperature diamond like carbon films: a transmission electron microscopy, scanning electron microscopy and cytotoxicity study", "venue": "", "year": 1994 }, { "abstract": "Microwave plasma enhanced chemical vapor deposition has been used to grow diamond films at substrate temperatures down to 435 degC using CO2/CH4 gas mixtures. An Arrhenius plot of growth rate as a function of substrate temperature yields a value for the activation energy for the growth step of 28 kJ mol 1. This is lower than that measured previously for CH4/H2 systems and hints at a different gas surface chemistry when using CH4/CO2 plasmas. Molecular beam mass spectrometry has been used to measure simultaneously the concentrations of the dominant gas phase species present during growth, for a wide range of plasma gas mixtures (0% 80% CH4, balance CO2) The CHEMKIN computer package has also been used to simulate the experimental results in order to gain insight into the major reactions occurring within the microwave plasma. The calculated trends for all species agree well with the experimental observations. Using these data, the model for the gas phase chemistry can be reduced to only four overall reactions.", "author_names": [ "James R Petherbridge", "Paul W May", "S R J Pearce", "Keith N Rosser", "Michael N R Ashfold" ], "corpus_id": 55540235, "doc_id": "55540235", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "Low temperature diamond growth using CO2/CH4 plasmas: Molecular beam mass spectrometry and computer simulation investigations", "venue": "", "year": 2001 }, { "abstract": "A new regime for plasma assisted chemical vapor deposition (CVD) of diamond is reported in which high quality diamond films can be deposited on silicon with relatively high ratios of methane in hydrogen mixtures and at significantly lower substrate temperatures than previously reported. The deposition was achieved in a microwave plasma discharge with a feed gas consisting of a mixture of only methane and hydrogen. The surface temperature of a molybdenum sample, when exposed to the same plasma environment, was measured at 500 degC with an infrared scanning camera. This substrate temperature is substantially lower than the 700 1000 degC range generally regarded as the optimal regime for CVD diamond growth. Analysis by Raman spectroscopy showed that films deposited with a 2% methane in hydrogen mixture produced a near graphite free diamond film at our reported low temperature regime, while deposition at 1000 degC resulted in films with a much higher graphitic content.", "author_names": [ "Wen L Hsu", "D M Tung", "Elke Fuchs", "K F Mccarty", "A Joshi", "Rao R Nimmagadda" ], "corpus_id": 123161604, "doc_id": "123161604", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Low temperature diamond growth in a microwave discharge", "venue": "", "year": 1989 }, { "abstract": "Abstract The interaction of chlorine with CVD diamond surfaces has been studied using Auger and photoelectron spectroscopy techniques, with reference to the development of low temperature growth models for diamond using halogen based precursors. Chlorine is found to adsorb on the clean CVD surface with a sticking probability of ~0.001 at 300 K, although this can be enhanced by prehydrogenation of the surface and by raising the substrate temperature. Adsorbed chlorine desorbs from the surface over a wide temperature range below 500degC, and is also very efficiently etched away by atomic hydrogen. Chlorine has therefore little tendency to poison the growth surface, and thus is capable of acting as a catalyst for low temperature growth.", "author_names": [ "S Proffitt", "Christopher H B Thompson", "Aurora Gutierrez-Sosa", "Nathan J Paris", "Nagindar K Singh", "Richard B Jackman", "John S Foord" ], "corpus_id": 94405933, "doc_id": "94405933", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Understanding the chemistry of low temperature diamond growth: an investigation into the interaction of chlorine and atomic hydrogen at CVD diamond surfaces", "venue": "", "year": 2000 }, { "abstract": "Abstract Using magneto active plasma CVD, diamond films have been fabricated at 0.01 torr with a substrate temperature of about 400degC. From the viewpoint of increasing plasma density, a gas mixture,CH 3 OH/(H 2 +He) obtained by adding a helium to a usually used gas mixtureCH 3 OH/H 2 has been employed in this study. For a constant CH 3 OH concentration (30% microcrystalline diamond films of good quality can be obtained at a ratio ofHe/(H 2 +He) up to 50% and the growth rate increases with an increase in the ratio. WhenHe/(H 2 +He) is higher than 50% graphite appears in the film because of the heavy bombardment on the diamond surface by the accelerated helium species in the plasma at low pressure (0.01 torr)", "author_names": [ "Motokazu Yuasa", "Osamu Arakaki", "J S Ma", "Akio Hiraki", "Hiroshi Kawarada" ], "corpus_id": 136377155, "doc_id": "136377155", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Low temperature diamond film fabrication using magneto active plasma CVD", "venue": "", "year": 1992 } ]

[ { "abstract": "The new paradigm of electronics, 'spintronics' promises to extend the functionality of information storage and processing in conventional electronics. The principal spintronics device, the 'spin valve' consists of two magnetic layers decoupled by a spin transporting spacer, which allows parallel (on) and antiparallel (off) alignment of the magnetizations (spins) of the two magnetic layers. The device resistance then depends on the spin alignment controlled by the external magnetic field. In pursuit of semiconductor spintronics, there have been intensive efforts devoted to develop room temperature magnetic semiconductors and also to incorporate both inorganic semiconductors and carbon based materials as the spin transporting channels. Molecule/organic based magnets, which allow chemical tuning of electronic and magnetic properties, are a promising new class of magnetic materials for future spintronic applications. Here, we report the realization of an organic based magnet as an electron spin polarizer in the standard spintronics device geometry. A thin non magnetic organic semiconductor layer and an epitaxial ferromagnetic oxide film were employed to form a hybrid magnetic tunnel junction. The results demonstrate the spin polarizing nature of the organic based magnetic semiconductor, vanadium(TCNE: tetracyanoethylene)(x) (x approximately 2; T(c) approximately 400 K) and its function as a spin injector/detector in hybrid magnetic multilayer devices.", "author_names": [ "Jung-Woo Yoo", "Chia-Yi Chen", "Ho Won Jang", "Chung Wung Bark", "Vladimir N Prigodin", "C B Eom", "Arthur J Epstein" ], "corpus_id": 21553460, "doc_id": "21553460", "n_citations": 169, "n_key_citations": 1, "score": 1, "title": "Spin injection/detection using an organic based magnetic semiconductor.", "venue": "Nature materials", "year": 2010 }, { "abstract": "Nature Materials 9, 638 642 (2010) published online: 18 July 2010; corrected after print: 23 July 2010. In the original version of this article published online and in print, the received date should have been 29 December 2009, not 2010. This has been corrected in the PDF and HTML versions of this Letter.", "author_names": [ "Jung-Woo Yoo", "Chia-Yi Chen", "Ho Won Jang", "Chung Wung Bark", "Vladimir N Prigodin", "C B Eom", "Arthur J Epstein" ], "corpus_id": 139495520, "doc_id": "139495520", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Erratum: Spin injection/detection using an organic based magnetic semiconductor", "venue": "", "year": 2010 }, { "abstract": "Ferromagnetic semiconductors with structural flexibility are an indispensable feature for future flexible spin electronic applications. In this case, we introduce magnetic ingredients into an organic semiconductor, namely, pentacene, to form a ferromagnetic organic semiconductor (FOS) The first observation for ferromagnetic Ni doped pentacene semiconductors at room temperature in the field of semiconductor spintronics is reported in this article. To date, the mechanism of FOSs with ferromagnetism is not understood yet, especially when their Curie temperature is enhanced above room temperature. Here, we demonstrate dopants of Ni atoms and the modulation of the growth temperature in the FOS films to achieve room temperature ferromagnetic properties in a series of FOS films, one of which has a maximum coercivity of 257.6 Oe. The spin exchange interaction between a Ni atom and a pentacene molecule is detected through the magnetic hysteresis obtained using a superconducting quantum interference device magnetometer. We verify the effectiveness of this spin coupling through magnetic force microscopy, Raman spectroscopy, scanning Kelvin probe microscopy, and theoretical simulation. A model for the indirect spin coupling between Ni atoms is proposed for the mechanism of room temperature ferromagnetic ordering of spins due to the exchange force indirectly. We believe that the p electrons of pentacene molecules at the triple state for this model can support the spin coupling of electrons of Ni atoms. Our findings facilitate the development of brand new spintronic devices with structural flexibility and room temperature ferromagnetism.", "author_names": [ "Wei-Yang Chou", "Sheng-Kuang Peng", "Fu-Hsuan Chang", "Jr-Jeng Ruan", "Tsung Yeh Ho" ], "corpus_id": 235960189, "doc_id": "235960189", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Ferromagnetism above Room Temperature in a Ni Doped Organic Based Magnetic Semiconductor.", "venue": "ACS applied materials interfaces", "year": 2021 }, { "abstract": "summary, we have successfully produced highly ordered arrays of single crystalline antimony nanowires with diameters of 40 nm in porous anodic alumina membranes by pulsed electrodeposition. The results of XRD and HRTEM indicate that the nanowires have a uniform hexagonal antimony single crystalline structure and grow along the [112 A 0] direction. The resistance at zero magnetic field demonstrates that single crystalline antimony nanowires with diameters of 40 nm remain metallic in character. It would be very interesting to produce a metal+ semiconductor nanowire heterogeneous junction array consisting of antimony metal and bismuth semiconductor. Further work is under way. Experimental The AAM was prepared as follows: high purity (99.999 aluminum was electropolished at 23 V in a mixture solution of 70 perchloric acid and etha nol (1:9) at 4 C for 2 min. Anodization was carried out at 40 V DC in 0.25 M aqueous oxalic acid electrolyte at 7 C. After the anodization, the central sub strate was removed in a saturated SnCl 4 solution, and the surrounding aluminum was retained as a support. Then the barrier was dissolved in 6 wt. phos phoric acid solution at 30 C for 60 min. Finally, a layer of Au was sputtered onto one side of the AAM to serve as the working electrode. Field emission microscopy observations indicate that the AAM is an almost perfect hexagonally arranged nanochannel array with a channel diameter of 40 nm. The antimony plating solution consisted of 0.02 The antimony nanowire arrays were observed using a field emission microscope (JEOL JSM 6700F) and a transmission electron microscope (JEOL 200CX and JEL 2010) For TEM analysis, the specimens were prepared by dissolving the AAMs with 5 wt. NaOH solution, dispersing the antimony nano wires in ethanol by ultrasonic vibration, and then placing drops of the dispersion on carbon films on a copper grid. The FEM specimen was obtained by dissolving the upper part of the AAM with 5 wt. NaOH solution. The X ray diffraction spectrum was obtained using a rotating anode X ray diffractometer (D/MAX rA) with Cu Ka radiation (k 1.542 The electrical resistance was measured by the standard DC four probe method in the temperature range from 20 K to 273 K. In the past decade there has been extensive progress in using the spin property of electrons in inorganic multilayers as a means of introducing revolutionary new types of electronics (e.g. spin valves, spin light emitting diodes) termed spin tronics. [1] Challenges including improved", "author_names": [ "Vladimir N Prigodin", "N P Raju", "Konstantin Pokhodnya", "Joel S Miller", "Arthur J Epstein" ], "corpus_id": 135890035, "doc_id": "135890035", "n_citations": 91, "n_key_citations": 0, "score": 0, "title": "Spin Driven Resistance in Organic Based Magnetic Semiconductor V[TCNE]x", "venue": "", "year": 2002 }, { "abstract": "Organic based magnets are intriguing materials with unique magnetic and electronic properties that can be tailored by chemical methodology. By using molecular layer deposition (MLD) we demonstrate the thin film fabrication of V[TCNE: tetracyanoethylene](x) of the first known room temperature organic based magnet. The resulting films exhibit improvement in surface morphology, larger coercivity (80 Oe) and higher Curie temperature/thermal stability (up to 400 K) Recently, the MLD method has been widely studied to implement fine control of organic film growth for various applications. This work broadens its application to magnetic and charge transfer materials and opens new opportunities for metal organic hybrid material development and their applications in various multilayer film device structures. Finally, we demonstrate the applicability of the multilayer V[TCNE](x) as a spin injector combining LSMO, an standard inorganic magnetic semiconductor, for spintronics applications.", "author_names": [ "Chi-yueh Kao", "Jung-Woo Yoo", "Yong Min", "Arthur J Epstein" ], "corpus_id": 578241, "doc_id": "578241", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Molecular layer deposition of an organic based magnetic semiconducting laminate.", "venue": "ACS applied materials interfaces", "year": 2012 }, { "abstract": "Over the last two decades organic spintronics has developed into a striving field with exciting reports of long spin diffusion lengths and spin relaxation times in organic semiconductors (OSCs) Easily processed and inexpensive, OSCs are considered a potential alternative to inorganic materials for use in spintronic applications. Spin currents have been detected in a wide range of materials, however, there is still uncertainty over the origin of the signals. Recently, we explored spin transport through an organic semiconductor with lateral spin injection and detection architectures, where the injected spin current is detected non locally via spin to charge conversion in an inorganic detector. In this work we show that the widely used control experiments like linear power dependence and inversion of the signal with the magnetic field are not sufficient evidence of spin transport and can lead to an incorrect interpretation of the signal. Here, we use in plane angular dependent measurements to separate pure spin signal from parasitic effects arising from spin rectification (SREs) Apart from well established anisotropic magnetoresistance (AMR) and anomalous Hall effect (AHE) we observed a novel effect which we call spurious inverse spin Hall effect (ISHE) It strongly resembles ISHE behaviour, but arises in the ferromagnet rather than the detector meaning this additional effect has to be considered in future work.", "author_names": [ "Piotr Skalski", "Olga Zadvorna", "Deepak Venkateshvaran", "Henning Sirringhaus" ], "corpus_id": 237347053, "doc_id": "237347053", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Distinguishing spin pumping from spin rectification in organic semiconductor based lateral spin pumping device architectures", "venue": "", "year": 2021 }, { "abstract": "Abstract The future of spin electronics or \"spintronics\" lies in the development of viable magnetic semiconductors that can effectively operate at room temperature Vanadium tetracyanoethylene (V[TCNE]~2) is a magnetic semiconductor with an ordering temperature well above that of room. Its highly disordered structure has hampered a comprehensive description of the interactions between the V and TCNE sublattices that give rise to its magnetic and electrical properties. We report the results of high resolution x ray absorption (XAS) and magnetic circular dichrosim (MCD) studies probing the electronic structure of V[TCNE]~2 in an effort to elucidate the nature of these interactions. Included in this study are the first reports of gas phase neutral TCNE XAS spectra as well as the first reports of MCD spectra of the carbon and nitrogen absorption edges for the V[TCNE]~2 system. The vanadium spectrum reveals a spin split L3 and L2 spectrum that is qualitatively modeled for V(II) using crystal field multiplet (CFM) theory calculations except for a region of excess intensity on the high energy side of both the L3 and L2 absorption edges. We speculate that the origin of this excess intensity is vanadium present in valence states higher than V(II) and antibonding states from the hybridization of the V centers and TCNE. Despite the localized nature of the x ray absorption process the C and N spectra of the TCNE suggest that we are probing molecular final states of TCNE from different sites rather atomically isolated states. In addition, the carbon and nitrogen absorption spectra reveal that this molecular orbital structure remains largely intact in going from the gas phase to the condensed phase in V[TCNE]~2.", "author_names": [ "Derek M Lincoln" ], "corpus_id": 94620038, "doc_id": "94620038", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The electronic structure and field effects of an organic based room temperature magnetic semiconductor", "venue": "", "year": 2007 }, { "abstract": "Tailoring molecular spinterface between novel magnetic materials and organic semiconductors offers promise to achieve high spin injection efficiency. Yet it has been challenging to achieve simultaneously a high and nonvolatile control of magnetoresistance effect in organic spintronic devices. To date, the largest magnetoresistance ~300% at T 10 K) has been reached in tris (8 hydroxyquinoline) aluminum (Alq3) based organic spin valves (OSVs) using La0.67Sr0.33MnO3 as a magnetic electrode. Here we demonstrate that one type of perovskite manganites, i.e. a (La2/3Pr1/3)5/8Ca3/8MnO3 thin film with pronounced electronic phase separation (EPS) can be used in Alq3 based OSVs to achieve a large magnetoresistance (MR) up to 440% at T 10 K and a typical electrical Hanle effect as the Hallmark of the spin injection. The contactless magnetic field controlled EPS enables us to achieve a nonvolatile tunable MR response persisting up to 120 K. Our study suggests a new route to design high performance multifunctional OSV devices using electronic phase separated manganites. Organic materials hold great potential of for spintronic applications. Here the authors show electronic phase dependent magnetoresistance (MR) effect in LPCMO/Alq3/Co junctions with large MR up to 440% at 10 K as well as electrical Hanle effect as the Hallmark of the spin injection.", "author_names": [ "Wenting Yang", "Qian Shi", "Tian Miao", "Qiang Li", "Peng Cai", "Hao Liu", "Hanxuan Lin", "Yu Bai", "Yinyan Zhu", "Yang Yu", "Lina Deng", "Wenbin Wang", "Lifeng Yin", "Dali Sun", "X-G Zhang", "Jian Shen" ], "corpus_id": 201667060, "doc_id": "201667060", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Achieving large and nonvolatile tunable magnetoresistance in organic spin valves using electronic phase separated manganites", "venue": "Nature Communications", "year": 2019 }, { "abstract": "Figure 1 a) Device structure and b) schematic view of the energy levels of V[TCNE] x x 2) Spintronics is the new paradigm of electronics and utilizes the spin degree of freedom of the electron. 1 In addition to metalbased spintronic devices, which already have wide applications (e.g. read heads of hard disk drives) semiconductor spintronics provides the possibility to combine logic, communication, and storage operation using hybrid devices. 2 Recently, spintronic devices based on organic materials have attracted much attention because of the potential long spin lifetime due to low spin orbit coupling and weak hyperfi ne interaction, as well as the ability to fabricate low cost, light weight, and mechanically fl exible devices. 3 9 Organic semiconductors have been used as the spacers in spin valve devices with ferromagnetic metal or transitional metal oxide contacts. One fundamental obstacle for spin injection from a ferromagnetic metal into a semiconductor is the conductivity mismatch. 10 The development of fully spinpolarized magnetic semiconductors offers a promising route to circumvent this problem. Organic based magnets such as V[TCNE] x x 2, TCNE: tetracyanoethylene) provide advantages including high magnetic ordering temperature, fully spin polarized semiconducting electronic structure, chemical tunability, and low temperature processing. 11 Here, we show results for spin injection and detection in an all organic based spin valve using the organic magnetic semiconductor V[TCNE] x as both the spin injector and analyzer. We observed unusual inverted spin valve effect and propose that the negative magnetoresistance (MR) originates from the spin dependent tunneling between highly spin polarized bands split by Coulomb interaction. V[TCNE] x is the fi rst reported room temperature moleculebased magnet with magnetic ordering temperature T C 400 K. 12 The magnetic order originates from the antiferromagnetic coupling between the three unpaired electrons of the V 2", "author_names": [ "Bin Li", "Chi-yueh Kao", "Jung-Woo Yoo", "Vladimir N Prigodin", "Arthur J Epstein" ], "corpus_id": 205240526, "doc_id": "205240526", "n_citations": 60, "n_key_citations": 1, "score": 0, "title": "Magnetoresistance in an all organic based spin valve.", "venue": "Advanced materials", "year": 2011 }, { "abstract": "The ferromagnetic electrode on which a clean high quality electrode/interlayer interface is formed, is critical to achieve efficient injection of spin dependent electrons in spintronic devices. In this work, we report on the preparation of graphene passivated cobalt electrodes for application in vertical spin valves (SVs) In this strategy, high quality monolayer and bi layer graphene sheets have been grown directly on the crystal Co film substrates in a controllable process by chemical vapor deposition. The electrode is oxidation resistant and ensures a clean crystalline graphene/Co interface. The AlO x based magnetic junction devices using such bottom electrodes, exhibit a negative tunnel magneto resistance (TMR) of ca. 1.0% in the range of 5 K 300 K. Furthermore, we have also fabricated organic based SVs employing a thin layer of fullerene C60 or an N type polymeric semiconductor as the interlayer. The devices of both materials show a tunneling behavior of spin polarized electron transport as well as appreciable TMR effect, demonstrating the high potential of such graphene coated Co electrodes for organic based spintronics.", "author_names": [ "Guoqing Zhou", "Guoqiang Tang", "Tian Li", "Guoxing Pan", "Zanhong Deng", "Fapei Zhang" ], "corpus_id": 125389677, "doc_id": "125389677", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Graphene passivated cobalt as a spin polarized electrode: growth and application to organic spintronics", "venue": "", "year": 2017 } ]

[ { "abstract": "PurposeFrom an early stage, retinitis pigmentosa (RP) patients suffer from night blindness which causes nocturnal mobility difficulties. We created a wearable visual aid that uses a high performance see through display, and added a high sensitivity camera with a complementary metal oxide semiconductor sensor. Here, we evaluate the device's efficacy for helping night blindness sufferers walk in the dark.Study designProspective clinical study.MethodsTwenty eight subjects underwent binocular visual acuity testing in the dark without (power off) and with (power on) the device. The test was carried out in a darkened room. We recorded the number of trial errors and the time it took each subject to arrive at the goal both with and without the aid of our device.ResultsOur device effectively assists walking in RP patients with mobility problems in the dark.ConclusionBinocular visual acuity in the dark was significantly improved with the aid of our device. In the walking test, the number of errors decreased greatly with the device, and the travel time was significantly shortened.", "author_names": [ "Yasuhiro Ikeda", "Shunji Nakatake", "Jun Funatsu", "Kohta Fujiwara", "Takashi Tachibana", "Yusuke Murakami", "Toshio Hisatomi", "Shigeo Yoshida", "Hiroshi Enaida", "Tatsuro Ishibashi", "Koh-Hei Sonoda" ], "corpus_id": 57373493, "doc_id": "57373493", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Night vision aid using see through display for patients with retinitis pigmentosa", "venue": "Japanese Journal of Ophthalmology", "year": 2018 }, { "abstract": "Ranibizumab therapy is the first treatment for neovascular AMD to improve vision for most patients. The benefits apply to all angiographic subtypes of neovascular AMD and across all lesion sizes. Although the pivotal phase III trials (MARINA and ANCHOR) used monthly injections of ranibizumab for 2 years, the ongoing PIER, PrONTO, and SAILOR trials are investigating less frequent dosing regimens, and preliminary results from the PrONTO study suggest that fewer injections will most likely result in visual acuity improvements similar to the results from the phase III trials. When comparing the ANCHOR results with the FOCUS results, it also becomes apparent that the combination of ranibizumab with PDT does not necessarily result in better visual acuity outcomes, and the use of PDT may even reduce the visual acuity benefits achieved with ranibizumab alone (see Figs. 1 3) It seems unlikely that combination therapy provides any significant advantage over ranibizumab alone unless the combination of PDT and ranibizumab can decrease the need for frequent retreatment. The results from the PrONTO Study already suggest that less frequent treatment with ranibizumab is possible by using a variable dosing regimen with OCT. Ranibizumab also seems to be safe, with the 2 year MARINA data showing no increase in the incidence of systemic adverse events that could be associated with anti VEGF therapy, such as myocardial infarction and stroke. There was a hint of a safety concern, however, in the pooled 1 year safety results from the MARINA and ANCHOR trials. Although the combined rate of myocardial infarction and stroke during the first year of the ANCHOR and MARINA trials was similar in the control and the 0.3 mg ranibizumab arms (1.3% and 1.6% respectively) these adverse events were slightly higher in the 0.5 mg ranibizumab arm (2.9% These differences are not statistically significant, however, and probably do not represent a dose dependent increase in risk because the 2 year results from the MARINA trial with the same monthly injection regimen showed no increased risk of thromboembolic events. In December 2005, Genentech submitted a Biologics License Application to the FDA for the use of ranibizumab in the treatment of neovascular wet AMD based on 1 year clinical efficacy and safety data from the two pivotal phase III trials, ANCHOR and MARINA, and the phase I II FOCUS trial. Genentech has been granted a 6 month Priority Review from the FDA with a decision anticipated 6 months from the December submission date or by the end of June 2006 [29] By the summer of 2006, this revolutionary therapy should be available for the treatment of neovascular AMD. At that time, the major dilemma facing most retina specialists will be whether to use intravitreal ranibizumab or intravitreal bevacizumab, the low cost alternative, for the treatment of neovascular AMD.", "author_names": [ "Philip J Rosenfeld", "Ryan M Rich", "Geeta A Lalwani" ], "corpus_id": 21994863, "doc_id": "21994863", "n_citations": 283, "n_key_citations": 14, "score": 1, "title": "Ranibizumab: Phase III clinical trial results.", "venue": "Ophthalmology clinics of North America", "year": 2006 }, { "abstract": "Loss of central vision from geographic atrophy (GA) is a late stage complication of age related macular degeneration (AMD) as the central foveal region becomes consumed by the disease. Until recently, GA had not received the attention it deserved from the pharmaceutical industry. Over the years, most of the clinical trial community has been focused on the exudative or neovascular form of AMD due to the rapid and severe vision loss often associated with this form of the disease. With the success of vascular endothelial growth factor inhibitors in slowing and preventing the devastating vision loss from neovascularization in exudative AMD, the development of macular atrophy after anti vascular endothelial growth factor therapy and growth of GA in nonexudative AMD have become the most common causes of vision loss from AMD. The research by Chakravarthy et al (see http: www.aaojournal.org/article/S0161 6420(17)32513 7/fulltext) in this issue highlights the enormous impact of GA in", "author_names": [ "Philip J Rosenfeld" ], "corpus_id": 29169633, "doc_id": "29169633", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Preventing the Growth of Geographic Atrophy: An Important Therapeutic Target in Age Related Macular Degeneration.", "venue": "Ophthalmology", "year": 2018 }, { "abstract": "PURPOSE The goal was to evaluate how perceptual thresholds are related to electrode impedance, electrode size, the distance of electrodes from the retinal surface, and retinal thickness in six subjects blind as a result of retinitis pigmentosa, who received epiretinal prostheses implanted monocularly as part of a U.S. Food and Drug Administration (FDA) approved clinical trial. METHODS The implant consisted of an extraocular unit containing electronics for wireless data, power recovery, and generation of stimulus current, and an intraocular unit containing 16 platinum stimulating electrodes (260 or 520 microm diameter) arranged in a 4 x 4 pattern. The electrode array was held onto the retina by a small tack. Stimulation was controlled by a computer based external system that allowed independent control over each electrode. Perceptual thresholds (the current necessary to see a percept on 79% of trials) and impedance were measured for each electrode on a biweekly basis. The distance of electrodes from the retinal surface and retinal thickness were measured by optical coherence tomography on a less regular basis. RESULTS Stimulation thresholds for detecting phosphenes correlated with the distance of the electrodes from the retinal surface, but not with electrode size, electrode impedance, or retinal thickness. CONCLUSIONS Maintaining close proximity between the electrode array and the retinal surface is critical in developing a successful retinal implant. With the development of chronic electrode arrays that are stable and flush on the retinal surface, it is likely that the influence of other factors such as electrode size, retinal degeneration, and subject age will become more apparent. (ClinicalTrials.gov number, NCT00279500.", "author_names": [ "Chloe de Balthasar", "Sweta Patel", "Arup Roy", "Ricardo Freda", "Scott H Greenwald", "Alan Horsager", "Manjunatha Mahadevappa", "Douglas Yanai", "Matthew J Mcmahon", "Mark S Humayun", "Robert J Greenberg", "James D Weiland", "Ione Fine" ], "corpus_id": 3695155, "doc_id": "3695155", "n_citations": 170, "n_key_citations": 12, "score": 0, "title": "Factors affecting perceptual thresholds in epiretinal prostheses.", "venue": "Investigative ophthalmology visual science", "year": 2008 }, { "abstract": "The Laser in Glaucoma and Ocular Hypertension (LiGHT) trial. A multicentre, randomised controlled trial: design and methodology (see page 593) The Laser in Glaucoma and Ocular Hypertension trial is a multicentre randomised controlled trial investigating the health related quality of life, clinical and cost effectiveness of drops versus selective laser trabeculoplasty as a first line treatment.", "author_names": [ "Keith Barton", "James Chodosh", "Jost Bruno Jonas" ], "corpus_id": 13748269, "doc_id": "13748269", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Highlights from this issue", "venue": "British Journal of Ophthalmology", "year": 2018 }, { "abstract": "PURPOSE To determine the incidence and baseline clinical and anterior segment optical coherence tomography (AS OCT) predictors associated with residual angle closure as assessed by gonioscopy 1 year after laser peripheral iridotomy (LPI) in primary angle closure suspects (PACS) DESIGN Subanalysis of randomized controlled trial data. METHODS AS OCT images from 181 PACS subjects =50 years of age were analyzed using customized software before and 1 year after LPI. Other parameters assessed were intraocular pressure (IOP) and axial length (Axl) Residual angle closure was defined as the inability to see the posterior trabecular meshwork for at least 2 quadrants on gonioscopy after LPI. Multivariate regression analysis determined the baseline predictors of residual angle closure 1 year after LPI. RESULTS The mean age of participants was 62.4 (standard deviation 9.9) years. The majority were female (137, 75.7% and Chinese (174, 96.1% At 1 year post LPI, 148 (81.8% subjects had gonioscopic residual angle closure. Univariate analysis showed that baseline Axl, anterior chamber area, anterior chamber volume, angle opening distance at 750 mm from the scleral spur, and angle recess area were smaller while baseline lens vault and iris curvature were larger in residual angle closure subjects (all P .05) Multivariate analysis revealed that baseline iris volume (B 0.08, P .035) and baseline IOP (B 0.23, P .032) were predictors for residual angle closure. CONCLUSIONS One year after LPI, >80% of PACS had gonioscopic residual angle closure. Greater baseline iris volume and higher IOP at baseline are independent risk factors for residual gonioscopic angle closure.", "author_names": [ "Mani Baskaran", "Elizabeth Yang", "Sameer Trikha", "Rajesh Kumar", "Hon-Tym Wong", "Mingguang He", "Paul T K Chew", "Paul J Foster", "David S Friedman", "Tin Aung" ], "corpus_id": 205350064, "doc_id": "205350064", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Residual Angle Closure One Year After Laser Peripheral Iridotomy in Primary Angle Closure Suspects.", "venue": "American journal of ophthalmology", "year": 2017 }, { "abstract": "Proliferative vitreoretinopathy remains the most frequent cause of failure of retinal detachment repair. The manuscript by Bannerjee et al, \"Slow Release Dexamethasone in Proliferative Vitreoretinopathy: A Prospective Randomized Controlled Clinical Trial,\" (see p. 757) presents an important study searching for an effective therapy in eyes with retinal detachment associated with proliferative vitreoretinopathy (PVR) Many prior pharmacologic treatments have been tried, including the use of daunorubicin, 5 fluorouracil combined with low molecular weight heparin, colchicine, 13 cis retinoic acid, triamcinolone, and systemic steroids. The authors are to be congratulated for submitting this study because it reports negative results. Studies with statistically significant results are 3 times more likely to be published than studies where the results do not reach statistical significance. The publication of studies with negative results is very important because this information is useful in designing other studies attempting", "author_names": [ "John T Thompson" ], "corpus_id": 35745720, "doc_id": "35745720", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Negative Results Matter: Why Can't We Improve the Treatment of Proliferative Vitreoretinopathy?", "venue": "Ophthalmology", "year": 2017 }, { "abstract": "The role of internal limiting membrane peeling in epiretinal membrane surgery: a randomized controlled trial (see page 719) This two centre, randomised, controlled clinical trial compared the anatomical and functional outcomes after primary idiopathic epiretinal membrane peeling with or without internal limiting membrane peeling. The result suggests that ILM peeling in ERM surgery does not improve visual outcome at 12 months.", "author_names": [ "Keith Barton", "James Chodosh", "Jost Bruno Jonas" ], "corpus_id": 40720989, "doc_id": "40720989", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Highlights from this issue", "venue": "British Journal of Ophthalmology", "year": 2017 }, { "abstract": "The Macular Photocoagulation Study (MPS) is a multicenter, collaborative, clinical trial that provides important guidelines for the treatment of choroidal neovascularization from age related macular degeneration (AMD) presumed ocular histoplasmosis syndrome (POHS) and idiopathic neovascularization. In a previous editorial, Jampol 1 discussed the role of hypertension among patients in the MPS, showing that under some circumstances, patients with hypertension had a less beneficial response to laser photocoagulation. Another aspect of the MPS that has received almost no attention to date is the racial characteristics of patients enrolled in the trial. See also p 1701. The MPS includes three clinical trials for AMD: argon laser photocoagulation for extrafoveal membranes, krypton laser photocoagulation for juxtafoveal membranes, and argon or krypton laser photocoagulation for subfoveal membranes. As of July 1,1991, a total of 1319 patients had been enrolled in these trials (Maureen Maguire, PhD, written communication) Of these patients, 1314 were white, one was black, and", "author_names": [ "Lee Merrill Jampol", "James M Tielsch" ], "corpus_id": 28975936, "doc_id": "28975936", "n_citations": 73, "n_key_citations": 0, "score": 0, "title": "Race, macular degeneration, and the Macular Photocoagulation Study.", "venue": "Archives of ophthalmology", "year": 1992 }, { "abstract": "These words conclude the report of a clinical trial published in this issue of theArchivesthat was designed to evaluate the effects of nutritional supplements of vitamins A and E on the natural course of retinitis pigmentosa. This study is a tour de force in experimental design, execution, and statistical analysis. The investigators deserve congratulations on the successful completion of this ambitious, rigorous, and interesting study. See also pp 754 and 761. Retinitis pigmentosa can be a devastating disease for the patient who suffers night blindness, progressive visual field loss, and eventually loss of central vision. There is no cure for retinitis pigmentosa, and patients are in constant search of hope. Therefore, when interpreting the intriguing results of this clinical trial, it is important to use caution and to avoid drawing unwarranted conclusions that could lead to unreasonable expectations by patients. Despite our admiration of the design and execution", "author_names": [ "Robert W Massof", "Daniel Finkelstein" ], "corpus_id": 35990578, "doc_id": "35990578", "n_citations": 50, "n_key_citations": 0, "score": 0, "title": "Supplemental vitamin A retards loss of ERG amplitude in retinitis pigmentosa.", "venue": "Archives of ophthalmology", "year": 1993 } ]

[ { "abstract": "June 1980, volume 25 This study examines relationships among strategy, distinctive competence, and organizational performance. The analysis focuses on the perceptions of top managers in four industries (plastics, semiconductors, automotives, and air transportation) Findings indicate that these managers perceive four strategy types, Defender, Prospector, Analyzer, and Reactor, to be present within their industry. Defenders, Prospectors, and Analyzers all show competence in general and financial management. Beyond these two functions, Defenders and Prospectors have identifiable but different configurations of distinctive competence, while Analyzers' special capabilities are considerably less apparent. Reactors, as expected, have no consistent pattern of distinctive competence. Finally, although the data are only suggestive, Defenders, Prospectors, and Analyzers consistently outperform Reactors in competitive industries, but not in an industry that is highly regulated.", "author_names": [ "Charles C Snow", "Lawrence G Hrebiniak" ], "corpus_id": 143537755, "doc_id": "143537755", "n_citations": 1371, "n_key_citations": 19, "score": 1, "title": "Strategy, Distinctive Competence, and Organizational Performance.", "venue": "", "year": 1980 }, { "abstract": "William Jack Davies Goodall, \"one of the three pioneers of modern Chilean ornithology\" (Vuilleumier 2006) a Corresponding Fellow of the American Ornithologists' Union (AOU) (Wolfson 1953) and co recipient of the AOU's Brewster Memorial Award in 1973 (Banks 1974) was born on 13 September 1892 at his parents' home, St. Jean d'Acre Cottage, Kings Road, Bembridge on the Isle of Wight, England (certifi ed copy of an entry in register, Isle of Wight [FD 968782, 15 September 2010] By April 1911, when he signed the Census Schedule for 52 Oxford Gardens, North Kensington, London (see below) he had dropped his fi rst name and thereafter was known generally as Jack (Davies) Goodall. Although Goodall lived most of his life in Chile, a country with a strong Spanish influence where an individual uses a two name \"surname\" the fi rst being the father's and the second the mother's there is no known basis for Vuilleumier's (2006) indication that he ever used the name \"Jack Goodall Callaway\".Jack's father was William Henry Goodall (born c. 1855) (the surname was sometimes spelled Goodhall in the mid 1800s) who gave his occupation as \"scientific chemist\" when his son's birth was registered. Jack's mother was Alma Louise Callaway (born c. 1859) William Henry Goodall and Alma Callaway were married in 1883 in St. Helens, Isle of Wight. The 1911 English census returns indicates that the couple had been married for 27 years and had had four children. The eldest, our subject William Jack Davies Goodall, born nine years after his parents married, was followed by three sisters: Luisa Mary, Frances Josefi na and Almita Bessie. It is noteworthy that in 1901, at least on Census Day, Mrs. Alma Goodall and her three daughters were at 134 St. Helens Green, home of her elderly parents, William and Henrietta Callaway. At the same time, William Jack D. Goodall (then aged eight) was also not staying with either of his parents but was listed at his aunt's house at 12 St. Helens Green. She was Fanny H. Seymour, a widow aged 43 \"living on (her) own means\" with her daughters Marie and Cecily.A decade later, on Census Day, Sunday 2 April 1911, Jack was again away from the family home studying to be a naval architect (the profession of one of his uncles, Frank Clement Goodall) and \"passed the night\" at 52 Oxford Gardens, North Kensington, west London. He fi lled in the return for the house and signed it. Jack listed himself as \"nephew\" because the owner of 52 Oxford Gardens was another uncle, Jeremiah Matthews Goodall FZS (1862 1939) also of The Nest, Bembridge. Jeremiah was probably a most infl uential person in Jack Goodall's life, more so than his own father or his uncle Frank, although the evidence is entirely circumstantial. J. M. Goodall was a founding member of the Isle of Wight Natural History Society in 1919 and one of its original vice presidents (L. Snow, pers. comm. He was especially interested in birds' eggs (Cole Trobe 2000) and made several collecting trips in Argentina; it is possible that the main purpose of his visits to Argentina was business,", "author_names": [ "C Stuart Houston", "Fabian M Jaksic", "E Charles Nelson", "Tippitiwitchet Cottage" ], "corpus_id": 164204979, "doc_id": "164204979", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Jack Goodall (1892 1980) ornithologist and artist of \"Las aves de Chile\" Some biographical notes Jack Goodall (1892 1980) ornitologo y artista de \"Las aves de Chile\" Algunas notas biografi cas", "venue": "", "year": 1980 }, { "abstract": "Strategic behaviour has been defined as managing environmental risks and matching organisational capabilities with the opportunities offered by the environment (e.g. Hofer Schendel (1978) One possible theoretical framework for analysing strategies of a firm is the Miles Snow typology (Miles Snow, 1978) It has received considerable attention and has been tested empirically with respect to business strategy in various industries (Snow Hrebiniak, 1980; Hambrick, 1983) as well as marketing strategy (McDaniel Kolari, 1987) In this paper we attempt to apply the Miles Snow typology to technology strategy and to relate technology strategies to the perception of environment and project risks. Thus, we Empirical data from companies involved in biotechnology is used to study some key questions.", "author_names": [ "Ursula Weisenfeld-Schenk" ], "corpus_id": 153535324, "doc_id": "153535324", "n_citations": 42, "n_key_citations": 4, "score": 0, "title": "Technology strategies and the Miles Snow typology: a study of the biotechnology industries", "venue": "", "year": 1994 }, { "abstract": "IntroductionEntrepreneurship, attributed with qualities such as creativity, flexibility, ability to find novel solutions, opportunity recognition, proactiveness, value creation and risk taking in literature (Morris et. al. 2004, Covin and Slevin 1991; Snow and Hrebiniak, 1980; Knight, 1997) is of critical significance, especially, for small and medium scale enterprises. Entrepreneurial marketing, which lies in the intersection between marketing and entrepreneurship and aims at making proactive use of opportunities through innovative perspectives, can be considered a strong and flourishing alternative in boutique hotel marketing activities. The concept of entrepreneurial marketing is described as unplanned, non linear and visionary (Morris et. al. 2002: 4) marketing activities of the entrepreneur. In fact, such an entrepreneurial perspective helps enrich the marketing mix instead of diversifying it and leads to a more entrepreneurial perception of its content. The qualities attributed to entrepreneurship in the literature can also be found in entrepreneurial marketing activities which emerge through an entrepreneurial perspective on traditional marketing.Based on the question of 'Can entrepreneurial marketing be adopted in the tourism sector? and considering the relevant findings that show entrepreneurial marketing as suitable to small scale enterprises in the literature (Kocak, 2004; Geursen and Mulye, 2001; Morris et. al. 2002; Carson, 1995) the boutique hotels within this context were examined in this study. The ultimate aim of this study is to asses the applicability of the seven dimensions of entrepreneurial marketing (opportunity focus, proactiveness, innovativeness, calculated risk taking, resource leveraging, customer intensity and value creation) in boutique hotels and to identify the internalized applications which activate such marketing activities. In order to achieve this aim we tried to determine to what extent the current marketing approaches show convergence or divergence to the entrepreneurial marketing and attempted to identify the tools and applications that boutique hotels pursued in adapting entrepreneurial marketing processes in their own businesses. This study seeks to make a contribution to the understanding of the area of marketing in boutique hotels in general and more specifically, entrepreneurial marketing in boutique hotels. The originality of this study is stemmed from the fact that the notion of entrepreneurial marketing has not been examined empirically from the viewpoint of boutique hotels. The major motivation of this research is that entrepreneurial marketing in tourism sector and particularly in boutique hotel sector has received no or little attention up to now.This research undertook a qualitative method and an exploratory design, since the notion of entrepreneurial marketing in tourism, and particularly in the boutique hotel sector, is a relatively new and untouched issue so that the study seems to be a preliminary one for the subsequent researches in this field. The semi structured interview technique was used in this study as the principal method in collecting data. A semi structured interview form consisting of open ended questions encompassing seven dimensions of entrepreneurial marketing was constructed by the authors considering the relevant literature and previous research evidence.Literature ReviewThe Concept of EntrepreneurshipEntrepreneurship refers to the pursuit of creative or novel solutions to challenges confronting the firm, including the development or enhancement of products and services, as well as new administrative techniques and technologies for performing organizational functions (Knight, 1997:213) Stevenson et al. (1989) defined the entrepreneurship as \"the process of creating value by bringing together a unique package of resources to exploit an opportunity.\" The process includes the set of activities necessary to identify an opportunity, define a business concept, assess needed resources, acquire those resources, and manages and harvests the venture (Morris et al.", "author_names": [ "Rambabu Pentyala" ], "corpus_id": 157672787, "doc_id": "157672787", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Interface between Marketing and Entrepreneurship A Study of Boutique Hotels", "venue": "", "year": 2016 }, { "abstract": "Researchers have begun to focus on identifying organizational capabilities, but still relatively little is known on the types of business capabilities stimulating innovation. From this point forth, this study investigated the possible relationships among production capabilities, marketing capabilities and innovation. By the findings of this study we aim to reveal whether primary capabilities effect innovation or not and which one effect more. Many researchers suggest that capabilities can be determined via the value analysis of functional areas such as production, marketing, finance, research and development, human resource management (Snow and Hrebiniak, 1980; Hitt and Ireland, 1985; Acar, 1993; Hafeez, Zhang and Malak 2002; Based on this common idea and aiming to contribute a better understanding of innovation in relation to capabilities, firstly, a brief review of resource based view is given and then production and marketing capabilities evaulated in this study are discussed. For this study a research model and hypotheses have been developed. In order to test the model and hypothesis, 122 organizations that are operating in Kocaeli, in Turkey were surveyed. Which capabilities can contribute positively to innovation is tried to be determined by regression analysis. As a result, according to the findings from this study, it can be said that there are significant relationships among marketing capabilities, production capabilities and innovation.", "author_names": [ "Nurullah Genc" ], "corpus_id": 56475379, "doc_id": "56475379", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "RESOURCE BASED VIEW AND THE IMPACTS OF MARKETING AND PRODUCTION", "venue": "", "year": 2013 }, { "abstract": "Much diversification research has focused on related versus unrelated diversification and the benefits of each (e.g. Hoskisson and Hitt, 1990; Ramanujam and Veraderajan, 1989) Firms pursuing unrelated diversification attempt to reduce business risk (e.g. Amit and Wernerfelt, 1988) and systematic risk (e.g. Barton, 1988; Montgomery and Singh, 1984) creating a structure where each company in the corporate portfolio has access to internal capital. On the other hand, firms pursuing related diversification attempt to leverage competencies across multiple businesses (Prahalad and Hamel, 1990; Robbins and Wiersema, 1995; Snow and Hrebiniak, 1980) Though the tactics of these two diversification strategies are different, at a general level each is an attempt to exploit market inefficiencies. For example, successful unrelated diversification may occur when strategic business units (SBUs) acquire capital more efficiently from the parent corporation than from the market (e.g. Williamson, 1975) Likewise, successful related diversification may occur when firms leverage resources that competing organizations cannot imitate or duplicate (e.g. Argyres, 1996) In sum, diversification is an attempt to create and capitalize on inefficiencies surrounding certain market transactions. One type of transaction that is characterized by innate market inefficiencies involves the delivery of services. Scholars have identified two aspects that are often associated with the production and delivery of services (e.g. Mills, 1986; Normann, 1984) The first is intangibility (Kotler, 1983) While manufacturing firms produce tangible products, most services cannot be seen or touched. This gives rise to information asymmetry, where customers may have difficulty evaluating the quality of service output. This can reduce a customer's ability to make comparisons among competing services (Chase and Bowen, 1989) Second, customers typically participate in the production of a service (Mills, 1986; Skaggs and Huffman, 2003; Skaggs and Youndt, 2004) In most manufacturing environments, products are produced, inventoried, shipped, and then sold to customers; production and consumption occur at different times and often at different locations. However, the simultaneous nature of production and consumption in services requires customers to interact with the firm in order to receive the service (Chase and Bowen, 1989; Mills, 1986; Normann, 1984) Together, these two unique aspects of services (intangibility and customer involvement in the service production process) have been theorized to create market inefficiencies by constraining competitive forces. For example, Nayyar (1990) suggests that information asymmetry in services acts as a switching cost for customers. Because of the inherent difficulty in making comparisons of service output among competing firms, customers are more likely to stay with their current firm. Furthermore, customer participation in service production can act to limit the scope of the competitive arena, since services typically cannot be produced and then sold elsewhere (Mills, 1986; Normann, 1984) Given that successful diversification involves the creation and/or exploitation of market inefficiencies and that, unlike goods, services have innate characteristics that can create these inefficiencies, it is possible that firms producing both goods and services may have an advantage over those that are strictly manufacturing oriented. However, there is little to no research examining this issue. This is somewhat surprising given the dominance of services in the U.S. economy and the fact that many manufacturers are beginning to add service components. To that end, this study represents an initial investigation into whether, at a general level, diversification into services by manufacturers yields higher and more stable performance. Because this topic has received such little research attention, we view this as an exploratory study.", "author_names": [ "Bruce C Skaggs", "Scott B Droege" ], "corpus_id": 150721057, "doc_id": "150721057", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "The Performance Effects of Service Diversification by Manufacturing Firms", "venue": "", "year": 2004 }, { "abstract": "Widely used in contemporary organizational and management theories, as well as in the discursive universe of corporate consulting, the term strategy has become a target of attention and attributed with a variety meanings, definitions and models. Authors celebrate this diversity, or at least, find it inevitable, due to the semantic richness of the vocabulary and the intrinsically complex and mutable nature of that which has been commonly dealt with as strategy in the context of organizations (MINTZBERG; LAMPEL; AHLSTRAND, 2000; SMIRCICH; STUBBART, 1985; SNOW; HREBINIAK, 1980) Others defend a particular discipline in the field, especially to facilitate the accumulation of knowledge through the systematic use of a set of reasonably accepted concepts and alternatives to its operational use (VENKATRAMAN; GRANT, 1986) This paper aims to revisit the concept of strategy and its current use in management, from its specific usage, such as in the strategic management of people or communication strategy, as well as its general application, such as in organizational positioning, which constitutes a company's soul, its personality its reason for being.", "author_names": [ "Anthero de Moraes Meirelles", "Carlos Alberto Goncalves" ], "corpus_id": 147261159, "doc_id": "147261159", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "ESTRATEGIA: ACORDOS, DESACORDOS E REVISOES SOBRE O TEMA", "venue": "", "year": 2010 }, { "abstract": "Variability in the SO]and C1time series for the 1980s from 12 shallow snow pits a*ross the Greenland ice sheet is used to ewlua, te the record of the 1982 E1 Chich6n eruption *nd the potential for recording moderate northern equatorial eruption in single Greenland ice core. Composition of volcanic glass found in spring 1983 snow in one of the pits in the Summit region m*tches that from E1 Chich6n glass, thereby verifying the deposition of m*teri*l from the eruption. High N* *nd C1concentrations in this s*me l*yer probably represent deposition of the ree*ction products of h*lite *nd H2SO4 as observed in the stratosphere following the eruption. These findings *nd the presence of C1signal in five of the other pits indicate that the C1a*rosol component of some eruptions has the potential to remain *loft for *t least I year Mter the eruption. Some of these *erosols m*y be adsorbed onto tephm p*rticles. Distinct SO* 2pe*ks that c*n be confidently linked to E1 Chich6n were found in only 50% of the records developed through subseasonal s*mpling. However, in several other pits *n elewted baseline, thought to represent more lengthy periods of E1 ChichSn aerosol deposition as opposed to deposition from single snowfall event, were observed. Smoothing of the original d*t* by the c*lcul*tion of *nnu*l SO]flux resulted in the presence ofhigh flux v*lues between 1982 *nd 1984 (years thought to be *ffcctcd by E1 Chich6n aerosol deposition) in 9 of the 12 pits. These results suggest hat single ice core from *nywhere in Greenland m*y record signal from northern equatorial eruption of m*gnitude similar to that of E1 Chich6n *bout 75% of the time; this is despite the overall high levels of SO]deposition from *nthropogenic sources that now m*ke identification d qu*ntific*tion ofthe volcanic SO* 2portion of the record more difficult th*n obtaining the s*me d*t* for preindustri*l volcanism. Nevertheless, composite records from *ll the pits s*mpled yielded stmtospheric loading *20 Mt) and optical depth (r: 0.13) estimates imilar to stratospheric and satellite based measurements following the eruption. Equally high SO* 2concentration and flux values in snow from 1980 to 1982 reflect deposition from the series of middle to high northern latitude volcanic eruptions 1979 1981.", "author_names": [ "Gregory A Zielinski", "Jack E Dibb", "Qing Yang", "Paul A Mayewski", "Mark S Twickler" ], "corpus_id": 55024285, "doc_id": "55024285", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Variability in the SO and C 1 time series for the 1980 s from 12 shallow snow", "venue": "", "year": 2018 }, { "abstract": "Abstract. The local weather and climate of the Himalayas are sensitive and interlinked with global scale changes in climate, as the hydrology of this region is mainly governed by snow and glaciers. There are clear and strong indicators of climate change reported for the Himalayas, particularly the Jammu and Kashmir region situated in the western Himalayas. In this study, using observational data, detailed characteristics of long and short term as well as localized variations in temperature and precipitation are analyzed for these six meteorological stations, namely, Gulmarg, Pahalgam, Kokarnag, Qazigund, Kupwara and Srinagar during 1980 2016. All of these stations are located in Jammu and Kashmir, India. In addition to analysis of stations observations, we also utilized the dynamical downscaled simulations of WRF model and ERA Interim (ERA I) data for the study period. The annual and seasonal temperature and precipitation changes were analyzed by carrying out Mann Kendall, linear regression, cumulative deviation and Student's t statistical tests. The results show an increase of 0.8 C in average annual temperature over 37 years (from 1980 to 2016) with higher increase in maximum temperature (0.97 C compared to minimum temperature (0.76 C Analyses of annual mean temperature at all the stations reveal that the high altitude stations of Pahalgam (1.13 C and Gulmarg (1.04 C exhibit a steep increase and statistically significant trends. The overall precipitation and temperature patterns in the valley show significant decreases and increases in the annual rainfall and temperature respectively. Seasonal analyses show significant increasing trends in the winter and spring temperatures at all stations, with prominent decreases in spring precipitation. In the present study, the observed long term trends in temperature C year 1 and precipitation mm year 1 along with their respective standard errors during 1980 2016 are as follows: (i) 0.05 (0.01) and 16.7 (6.3) for Gulmarg, (ii) 0.04 (0.01) and 6.6 (2.9) for Srinagar, (iii) 0.04 (0.01) and 0.69 (4.79) for Kokarnag, (iv) 0.04 (0.01) and 0.13 (3.95) for Pahalgam, (v) 0.034 (0.01) and 5.5 (3.6) for Kupwara, and (vi) 0.01 (0.01) and 7.96 (4.5) for Qazigund. The present study also reveals that variation in temperature and precipitation during winter (December March) has a close association with the North Atlantic Oscillation (NAO) Further, the observed temperature data (monthly averaged data for 1980 2016) at all the stations show a good correlation of 0.86 with the results of WRF and therefore the model downscaled simulations are considered a valid scientific tool for the studies of climate change in this region. Though the correlation between WRF model and observed precipitation is significantly strong, the WRF model significantly underestimates the rainfall amount, which necessitates the need for the sensitivity study of the model using the various microphysical parameterization schemes. The potential vorticities in the upper troposphere are obtained from ERA I over the Jammu and Kashmir region and indicate that the extreme weather event of September 2014 occurred due to breaking of intense atmospheric Rossby wave activity over Kashmir. As the wave could transport a large amount of water vapor from both the Bay of Bengal and Arabian Sea and dump them over the Kashmir region through wave breaking, it probably resulted in the historical devastating flooding of the whole Kashmir valley in the first week of September 2014. This was accompanied by extreme rainfall events measuring more than 620 mm in some parts of the Pir Panjal range in the south Kashmir.", "author_names": [ "Sumira Nazir Zaz", "Shakil Ahmad Romshoo", "Ramkumar Krishnamoorthy", "Yesubabu Viswanadhapalli" ], "corpus_id": 104401415, "doc_id": "104401415", "n_citations": 26, "n_key_citations": 2, "score": 0, "title": "Analyses of temperature and precipitation in the Indian Jammu and Kashmir region for the 1980 2016 period: implications for remote influence and extreme events", "venue": "", "year": 2019 }, { "abstract": "L 18 19: the definition of threshold wind speed used here is questionable and a value of the threshold velocity with two decimal value may not be relevant for the abstract. Thanks! This has been changed in L 19: \"In a first order approximation, the travel distance increases linearly with the wind velocity, allowing for an estimate of a threshold wind velocity for snow particle entrainment and transport of 7.5 8.8 m s, most likely depending on the prevailing snow cover properties.\" P 1 l 30: the references to Gerber et al (2018) and Sharma et al (2019) are not fully appropriate here. Indeed, the paper by Gerber et al (2018) does not study blowing and drifting snow and the paper by Sharma et al (2019) focuses on snow bedforms, which are typically below the slope scale. This was a bit confusing as these references were referring to \"slope scale\" and not meant to refer to drifting and blowing snow. Slope scale can be few meters to hundreds of meters (Review Mott et al. 2018) Therefore, both papers should be OK in our opinion. Nevertheless, we added some more references: L33: \"Schon, P. Prokop, A. Vionnet, V. Guyomarc'h, G. Naaim Bouvet, F. and Heiser, M. Improving a terrain based parameter for the assessment of snow depths with TLS data in the Col du Lac Blanc area. Cold Regions Sci. Technol. 114, 15 26. doi: 10.1016/j.coldregions.2015.02.005, 2015. Shook, K. and Gray, D. M. Small scale spatial structure of shallow snow covers. Hydrol. Process. 10, 1283 1292, 1996.\" Discussion paper P 2 L 46: the paper by Gerber et al (2018) only concerns modelling and observations of snowfall in alpine terrain. It would be valuable to add references to other studies that also consider drifting and blowing snow. See Mott et al. (2018) for a list of relevant references. Thanks, we added two more references: L49: \"Guyomarc'h and Merindol 1998, Naaim Bouvet et al. 2010\" P 3 L 66 67: it would be interesting here to provide the link to the Envidat webpage that host the data collected during the campaign. Good point! We added a reference containing the link. L 93: \"The data collected during the campaign including that used in this study can be found at Raclets (2019)\" RACLETS: Envidat data repository, https:/www.envidat.ch/group/raclets field campaign, 2019. Table 1: the date for event 3 in the table differ from the date given in the text (L 129) We changed this. P 13 L 304: should it be \" 0.05 for period one\" We changed this. P 14 L 329 330: the dismantling date for the MRR and the SDS should be given in the Methods section. We added this to the Methods Section: L123: \"On 2019 03 21, the MRR and the instruments of the SDS were dismantled.\" References (used in this review and not present in the initial manuscript) All of the suggested references below were included in the manuscript. Aksamit, N. O. Pomeroy, J. W. (2016) Near surface snow particle dynamics from particle tracking velocimetry and turbulence measurements during alpine blowing snow storms. The Cryosphere, 10(6) 3043 3062. Fohn, P. M. (1980) Snow transport over mountain crests. Journal of Glaciology, 26(94) 469 480. Geerts, B. Pokharel, B. Kristovich, D. A. (2015) Blowing snow as a natural glaciogenic cloud seeding mechanism. Monthly Weather Review, 143(12) 5017 5033. Guyomarc'h, G. Merindol, L. (1998) Validation of an application for forecasting blowing snow. Annals of Glaciology, 26, 138 143. Guyomarc'h, G. Bellot, H. Vionnet, V. Naaim Bouvet, F. Deliot, Y. Fontaine, F. Naaim, M. (2019) A meteorological and blowing snow data set (2000 2016) from a high elevation alpine site (Col du Lac Blanc, France, 2720 m asl) Earth System Science Data, 11(1) 57 69. rinter friendly version Discussion paper Moore, G. W. K. (2004) Mount Everest snow plume: A case study. Geophysical research letters, 31(22) Naaim Bouvet, F. Bellot, H. Naaim, M. (2010) Back analysis of drifting snow measurements over an instrumented mountainous site. Annals of Glaciology, 51(54) 207217. Schmidt, R. A. (1980) Threshold wind speeds and elastic impact in snow transport. Journal of Glaciology, 26(94) 453 467.", "author_names": [ "Michele Guala Referee" ], "corpus_id": 214773835, "doc_id": "214773835", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Interactive comment on \"Radar measurements of blowing snow off a mountain ridge\" by Benjamin Walter et al", "venue": "", "year": 2020 } ]

[ { "abstract": "The application of materials to the thermal control of structures, photothermal/electrical conversion, and photovoltaic conversion are reviewed. Applications include solar and infrared reflectors, optical filters, transparent conductors, bulk semiconductor materials, semiconductor films, and selective solar absorbers. The use of thin films in many conservation and photothermal applications is presently economical, but the economics of photothermal/electrical and photovoltaic conversion is still being investigated. The means of obtaining selective solar absorbers which have a high solar absorptance and low ir emittance are discussed, and specific data on an electrodeposited black chrome selective absorber is presented. It is shown that solar electric generating plants must be constructed at a cost of about $50/m2 to be competitive with other electrical generating plants, and that a meaningful impact on the electrical energy economy will require a fabrication rate of greater than 1.8 x 108 m2 (50 square miles) per year. Present high volume deposition capabilities are reviewed, and it is shown that for some types of deposition, namely electrodeposition, e beam vacuum evaporation, and possibly sputter deposition, facilities exist which approach the desired volumes.", "author_names": [ "Dm Mattox" ], "corpus_id": 97500255, "doc_id": "97500255", "n_citations": 20, "n_key_citations": 0, "score": 1, "title": "Solar energy materials preparation techniques", "venue": "", "year": 1975 }, { "abstract": "Abstract Vacuum adsorption was conducted to fabricate bio based polyethylene glycol (PEG)/wood flour (WF) composites as novel shape stable phase change materials (SSPCMs) The structure property relationships and comprehensive performance of PEG/WF phase change materials (PCMs) prepared with different average molecular weights of PEG and different length to diameter ratios of WF were investigated through various characterization techniques. The relationship between the average molecular weight and mass content of PEG with the properties and structure of the prepared PEG/WF PCMs was evaluated. Leakage test results showed that WF with a high length to diameter ratio (HWF) exhibited much higher adsorption capacity for PEG than that of WF with a low length to diameter ratio (LWF) The maximum adsorption content of PEG was found to be 70 wt% in those PEG/HWF PCMs and both proceeded with excellent shape stability without leakage when the average molecular weight of PEG was more than 4000. The maximum content of PEG1000 in novel PEG/HWF PCMs without any leakage above the melting point of PEG was 75 wt% Fourier transform infrared (FT IR) spectroscopy results indicated that physical interactions occurred between WF and PEG, but chemical reactions did not take place. X ray diffraction (XRD) analysis demonstrated that the crystallization of PEG in SSPCMs decreased. Differential scanning calorimetry (DSC) analysis demonstrated that the phase transition temperature did not depend on the content and length to diameter ratio of the WF. Simultaneously, the highest melting latent heat of the prepared PEG/HWF SSPCM was 108.6 J/g, and its enthalpy efficiency reached more than 75.05% Thermal cycling test and TGA analysis results demonstrated that PEG/WF SSPCMs had good thermal reliability and chemical stability and showed potential for applications in solar thermal energy storage and biomass energy.", "author_names": [ "Xiang Lu", "Wei-ping Tu", "Zhuohong Yang", "Teng Yuan" ], "corpus_id": 198328587, "doc_id": "198328587", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Solvent free preparation of bio based polyethylene glycol/wood flour composites as novel shape stabilized phase change materials for solar thermal energy storage", "venue": "Solar Energy Materials and Solar Cells", "year": 2019 }, { "abstract": "Latent heat storage systems,using phase change materials(PCMs),is one of effective ways to store thermal energy,which is widely applied in the areas of solar industrial process heat supply,heat recovery in industrial batch processes and energy saving in buildings.Previous research advances on the available phase change heat storage materials are reviewed,and the classification,choice,properties and applications on thermal storage techniques and materials are also presented.Especially,the problem of the classification,preparation route and application of medium temperature PCMs in 100 450temperature range is emphatically considered.An insight of the coming efforts to develop new classes of medium temperature PCMs is provided,and its corresponding prospective applications and developments are anticipated.A favorable proposal on developing the well properties micro/nano structured composite PCMs in future work is presented.", "author_names": [ "Wu Jianfen" ], "corpus_id": 138491759, "doc_id": "138491759", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Review on the Medium temperature Phase Change Materials Used for Solar Energy Thermal Storage", "venue": "", "year": 2014 }, { "abstract": "Abstract Optimizing photocatalysts to function within the visible region offers enhanced economics considering that 40% of the sun's energy is in the visible region, compared to just 4% in the UV region. To better utilize available solar flux, nanocomposite materials using TiO2 nanoparticles and single walled carbon nanotubes (SWCNTs) have been studied. Separating the SWCNT bundles using surfactants combined with a photo assisted sol gel preparation produced low band gap", "author_names": [ "Karishma Piler", "Jennifer Watters", "Tracy J Benson" ], "corpus_id": 225019100, "doc_id": "225019100", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Band gap tuning of TiO2 NP SWCNT nanocomposite materials using surfactant synthesis techniques", "venue": "", "year": 2020 }, { "abstract": "This review is objectively positioned and aimed at bringing to the fore the advances made in nanotechnology and present knowledge on the preparation (i.e. physicochemical, physicomechanical, and biological procedures) characterization (i.e. the use of several techniques to appraise the particle sizes, crystal geometry, and chemical composition, claims in the agro allied industries (i.e. construction of farm implements) electronics (i.e. glowing materials) medical (i.e. genetically modified plants) renewable energy( i.e. the harvesting of wind, solar and biomass energy in agriculture) oil/gas(i.e. the use of cracked oil in the production of fertilizers) textiles (i.e. weed control by landscape fabric) environmental remediation (i.e. the production of eco friendly materials using solid state fermentation) and the military (i.e. the erection of the military post and farming structures) and public perception on nano based technology. Also, the review has highlighted the positives and negatives in terms of challenges being faced by stakeholders in the nanotechnology sector. A good understanding of the strength (i.e. a steadily growing technology) and weaknesses (i.e. poor labeling and marketing strategy of products based on inadequate legislation) in these sectors as highlighted would provide a driving force for stakeholders to tackle the existing challenges herein.", "author_names": [ "D E Egirani", "Nabila Shehata", "Mohamed Hamdy Khedr" ], "corpus_id": 224801854, "doc_id": "224801854", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Review of Nano Materials in Agriculture and Allied Sectors: Preparation, Characterization, Applications, Opportunities, and Challenges", "venue": "", "year": 2020 }, { "abstract": "Abstract Erythritol (ME)/polyaniline (PANI) form stable phase change materials (PCMs) were prepared in isopropanol via a simple method. ME was dispersed in the solvent to form suspension at first. Form stable PCMs were then obtained by covering the dispersed ME particles with PANI particles, which in turn were synthesized via surface polymerization of aniline in the solvent. The prepared form stable PCMs were characterized by various characterization techniques. The results showed that the loading of ME in the form stable PCM with good form stability could attain 75% corresponding to a melting enthalpy of about 260 J/g. The supercooling degree of ME in the form stable PCMs was stably suppressed from 103 degC to 60 degC, which was resulted from that the PANI presented a lot of nucleation centers and facilitated the heterogeneous nucleation of ME. The solidification enthalpy of the form stable PCM was improved to 180 J/g, which was 50 J/g higher than that of pristine ME. Accelerated cyclic melting/freezing tests showed that the solidification temperature and the latent heat storage capacity of the prepared form stable PCMs remained stable over 100 melting/freezing cycles. The form stability of the form stable PCMs were originated from that the ME particles were covered by a layer of PANI particles, and the PANI particles could adsorb the liquified ME. This work presented a protocol for preparation of polymer based sugar alcohols form stable PCMs.", "author_names": [ "Yu-hang Chen", "Liufeng Jiang", "Yu Fang", "Li Shu", "Yu-Xiang Zhang", "Ting Xie", "Kun Li", "Ni Tan", "Ling Ling Zhu", "Zhong Cao", "Ju-lan Zeng" ], "corpus_id": 197069492, "doc_id": "197069492", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Preparation and thermal energy storage properties of erythritol/polyaniline form stable phase change material", "venue": "Solar Energy Materials and Solar Cells", "year": 2019 }, { "abstract": "Throughout this thesis, samples of various materials with applications in energy converting devices have been prepared by focused ion beam machining and investigated by transmission electron microscopy. Energy converting devices can be solar cells or light emitting diodes, which turn light into electricity or vice versa. They can also be fuel cells or electrolyzer cells, which turn chemical energy into electricity or vice versa. To efficiently convert the energy, these devices require specialized materials. The results achieved by the characterization presented here include identifying twin and grain boundaries, the crystal structure and the chemical composition. The different transmission electron microscopy techniques and sample preparation methods used are explained and discussed. For example, the preparation of nanowires, which are used in solar cells and light emitting diodes, require additional steps to the standard in situ lamella lift out method. The nanowires have to be embedded in a polymer material by casting or spin coating and a frame lamella design is necessary to stabilize the thin region of interest. (Less)", "author_names": [ "Filip Lenrick" ], "corpus_id": 139028001, "doc_id": "139028001", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Focused Ion Beam Preparation and Transmission Electron Microscopy of Materials for Energy Applications", "venue": "", "year": 2016 }, { "abstract": "Indium containing visible light driven (VLD) photocatalysts including indiumcontaining oxides, indium containing sulfides, indium containing hydroxides, and other categories have attracted more attention due to their high catalytic activities for oxidation and reduction ability under visible light irradiation. This chapter will therefore concentrate on indium containing nano structured materials that demon strate useful activity under solar excitation in fields concerned with the elimination of pollutants, partial oxidation and the vaporization of chemical compounds, water splitting, and CO2 reduction processes. The indium containing photocatalysts can extend the light absorption range and improve the photocatalytic activity by doping, heterogeneous structures, load promoter, and morphology regulation. A number of synthetic and modification techniques for adjusting the band structure to harvest visible light and improve the charge separation in photocatalysis are discussed. In this chapter, preparation, properties, and potential applications of indium contain ing nano structured materials used as photocatalysis will be systematically summar ized, which is beneficial for understanding the mechanism and developing the potential applications.", "author_names": [ "Xiangchao Zhang", "Duan Huang", "Kaiqiang Xu", "Difa Xu", "Fang Liu", "Shiying Zhang" ], "corpus_id": 53342241, "doc_id": "53342241", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Indium Containing Visible Light Driven (VLD) Photocatalysts for Solar Energy Conversion and Environment Remediation", "venue": "", "year": 2016 }, { "abstract": "Abstract Sustainable solar energy powered desalination is a high priority research area, nowadays. Fresh potable water is one of humanity's fundamental needs for living and flourishing. Efficient techniques for producing pure water from saline water and industrial wastewater with less conventional energy use or using renewable energy are urgently needed. Solar stills are one of such alternatives to produce pure water using solar energy. Novelty of this write up is discussion of basic concepts such as working principle of nanofluid, heat transfer in nanofluid and different preparation methods. These areas are discussed to bring the readers closer to the present scenario of suspended nanostructured engineering materials for solar distillation. Cost analysis with and without suspended nanoparticles are also summarized. Authors have also thrown light on effects of NPs (nanoparticles) on environment and health of living beings as a means to promote this technology. An important result is that nanofluids thermal conductivity is proportional to nanoparticles concentration to a certain limit. So, each nanoparticle has its optimum concentration where thermal conductivity is maximum in order to give maximum yield of pure water.", "author_names": [ "Siva Ram Akkala", "Ajay Kumar Kaviti", "T Arunkumar", "Vineet Singh Sikarwar" ], "corpus_id": 233579667, "doc_id": "233579667", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Progress on suspended nanostructured engineering materials powered solar distillation a review", "venue": "", "year": 2021 }, { "abstract": "The shortage of source of energy and the environmental problems promote the quick development of renewable source of energy,of which photovoltaic industry develops most quickly.This paper introduces the development status quo of polysilicon,the basic materials of photovoltaic industry,focusing on review and analysis of the main preparation of solar energy silicon materials and some new techniques,and puts forward some suggestions for the development of polysilicon industry.", "author_names": [ "Zhou Xiao-ying" ], "corpus_id": 113359087, "doc_id": "113359087", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Review on the development and preparation of solar energy polysilicon", "venue": "", "year": 2010 } ]

[ { "abstract": "Quantum key distribution with single photons from a telecommunication wavelength quantum dot source is performed over a standard optical fibre link. The source was operated at a temperature of 70 K and gave g(2)(0)~0.166 with an efficiency of 5% after coupling into the single mode fibre. Correlation results are quoted without subtraction of detector dark counts and g(2)(0) as low as 0.1 was measured, at reduced efficiency. This source enabled a proof of principle demonstration of quantum key distribution over 35 km of fibre using the BB84 protocol and phase encoding.", "author_names": [ "P M Intallura", "Martin Ward", "O Z Karimov", "Zhiliang Yuan", "Patrick See", "Paola Atkinson", "David A Ritchie", "Andrew J Shields" ], "corpus_id": 121543325, "doc_id": "121543325", "n_citations": 11, "n_key_citations": 0, "score": 2, "title": "Quantum communication using single photons from a semiconductor quantum dot emitting at a telecommunication wavelength", "venue": "", "year": 2009 }, { "abstract": "We present the first demonstration of telecom fiber based quantum key distribution using single photons from a quantum dot in a pillar microcavity. The source offers both telecommunication wavelength operation at 1.3 microns and Purcell enhancement of the spontaneous emission rate. Several emission lines from the InAs/GaAs quantum dot are identified, including the exciton biexciton cascade and charged excitonic emission. We show an order of magnitude increase in the collected intensity of the emission from a charged excitonic state when temperature tuned onto resonance with the HE11 mode of the pillar microcavity, as compared to the off resonance intensity. Above and below GaAs bandgap optical excitation was used and the effect of the excitation energy on the photoluminescence investigated. Exciting below the GaAs bandgap offers significant improvement in the quality of the single photon emission and a reduction of the multi photon probability to 0.1 times the value for Poissonian light was measured, before subtraction of detector dark counts, the lowest value recorded to date for a quantum dot source at a fibre wavelength. We observe also the first evidence of Purcell enhancement of the spontaneous emission rate for a single telecommunication wavelength quantum dot in a pillar microcavity. We have incorporated the source into a phase encoded interferometric scheme implementing the BB84 quantum cryptography protocol and distributed a key, secure from the pulse splitting attack, over standard telecommunication optical fibre. We show a transmission distance advantage over that possible with (length optimized) uniform intensity weak coherent pulses at 1310 nm in the same system.", "author_names": [ "P M Intallura", "Martin Ward", "O Z Karimov", "Zhiliang Yuan", "Patrick See", "Andrew J Shields", "Paola Atkinson", "David A Ritchie" ], "corpus_id": 121069703, "doc_id": "121069703", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Quantum key distribution using a semiconductor quantum dot source emitting at a telecommunication wavelength", "venue": "SPIE OPTO", "year": 2008 }, { "abstract": "On demand indistinguishable single photon sources are essential for quantum networking and communication. Semiconductor quantum dots are among the most promising candidates, but their typical emission wavelength renders them unsuitable for use in fiber networks. Here, we present quantum frequency conversion of near infrared photons from a bright quantum dot to the telecommunication C band, allowing integration with existing fiber architectures. We use a custom built, tunable 2400 nm seed laser to convert single photons from 942 nm to 1550 nm in a difference frequency generation process. We achieve an end to end conversion efficiency of 35% demonstrate count rates approaching 1 MHz at 1550 nm with g 2 0 0.043 1 and achieve Hong Ou Mandel (HOM) visibilities of 60% We expect this scheme to be preferable to quantum dot sources directly emitting at telecom wavelengths for fiber based quantum networking.", "author_names": [ "Christopher L Morrison", "Markus Rambach", "Zhe Xian Koong", "Francesco Graffitti", "Fiona E Thorburn", "Ajoy Kar", "Yonghong Ma", "Sukin Park", "Jin Dong Song", "Nick G Stoltz", "Dirk Bouwmeester", "Alessandro Fedrizzi", "Brian D Gerardot" ], "corpus_id": 231719719, "doc_id": "231719719", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A bright source of telecom single photons based on quantum frequency conversion", "venue": "", "year": 2021 }, { "abstract": "(c) 2017 American Physical Society. The development of quantum relays for long haul and attack proof quantum communication networks operating with weak coherent laser pulses requires entangled photon sources at telecommunication wavelengths with intrinsic single photon emission for most practical implementations. Using a semiconductor quantum dot emitting entangled photon pairs in the telecommunication O band, we demonstrate a quantum relay fulfilling both of these conditions. The system achieves a maximum fidelity of 94.5% for implementation of a standard four state protocol with input states generated by a laser. We further investigate robustness against frequency detuning of the narrow band input and perform process tomography of the teleporter, revealing operation for arbitrary pure input states, with an average gate fidelity of 83.6% The results highlight the potential of semiconductor light sources for compact and robust quantum relay technology that is compatible with existing communication infrastructures.", "author_names": [ "Jan Huwer", "Martin Felle", "R Mark Stevenson", "Joanna Skiba-Szymanska", "Martin Ward", "Ian Farrer", "Richard Vincent Penty", "David A Ritchie", "Andrew J Shields" ], "corpus_id": 53415035, "doc_id": "53415035", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Quantum Dot Based Telecommunication Wavelength Quantum Relay", "venue": "", "year": 2017 }, { "abstract": "Entangled light sources are considered as core technology for multiple quantum network architectures. Of particular interest are sources that are based on a single quantum system as these offer intrinsic security due to the sub Poissonian nature of the photon emission process. This is important for applications in quantum communication where multi pair emission generally compromises performance. A large variety of sources has been developed, but the generated photons remained far from being utilized in established standard fiber networks, mainly due to lack of compatibility with telecommunication wavelengths. In this regard, single semiconductor quantum dots are highly promising photon pair sources as they can be engineered for direct emission at telecom wavelengths. In this work we demonstrate the feasibility of this approach. We report a week long transmission of polarization entangled photons from a single InAs/GaAs quantum dot over a metropolitan network fiber. The photons are in the telecommunication O band, favored for fiber optical communication. We employ a polarization stabilization system overcoming changes of birefringence introduced by 18.23 km of installed fiber. Stable transmission of polarization encoded entanglement with a high fidelity of 91% is achieved, facilitating the operation of sub Poissonian quantum light sources over existing fiber networks.", "author_names": [ "Z-H Xiang", "Jan Huwer", "R Mark Stevenson", "Joanna Skiba-Szymanska", "Martin Ward", "Ian Farrer", "David A Ritchie", "Andrew J Shields" ], "corpus_id": 73728801, "doc_id": "73728801", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Long term transmission of entangled photons from a single quantum dot over deployed fiber", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "One promising technology expected to enable long haul quantum communication networks with untrusted nodes are quantum relays. Their most practical implementation requires an entanglement source with operation at telecom wavelength and intrinsic single photon character. Here, we use a semiconductor quantum dot emitting in the O band to demonstrate for the first time a system fulfilling both of these criteria. For implementation of a standard 4 state QKD protocol with weak coherent input states, the system achieves mean fidelities above 88% Further characterization of the relay with process tomography reveals teleportation for arbitrary input states. The results represent a significant advance in demonstrating feasibility of semiconductor light sources for the development of infrastructure compatible quantum communication technology for multi node networks.", "author_names": [ "Jan Huwer", "Martin Felle", "R Mark Stevenson", "Joanna Skiba-Szymanska", "Martin Ward", "Ian Farrer", "Richard Vincent Penty", "David A Ritchie", "Andrew J Shields" ], "corpus_id": 34855914, "doc_id": "34855914", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Telecom wavelength quantum relay using a semiconductor quantum dot", "venue": "2017 Conference on Lasers and Electro Optics (CLEO)", "year": 2017 }, { "abstract": "Single photons and entangled photon pairs are a key resource of many quantum secure communication and quantum computation protocols, and non Poissonian sources emitting in the low loss wavelength region around 1,550 nm are essential for the development of fibre based quantum network infrastructure. However, reaching this wavelength window has been challenging for semiconductor based quantum light sources. Here we show that quantum dot devices based on indium phosphide are capable of electrically injected single photon emission in this wavelength region. Using the biexciton cascade mechanism, they also produce entangled photons with a fidelity of 87 4% sufficient for the application of one way error correction protocols. The material system further allows for entangled photon generation up to an operating temperature of 93 K. Our quantum photon source can be directly integrated with existing long distance quantum communication and cryptography systems, and provides a promising material platform for developing future quantum network hardware.Quantum light sources operating at telecom wavelength are a long sought goal for quantum technologies. Here, the authors show electrically injected emission of single photons and entangled photon pairs from indium phosphide based quantum dots, operating up to a temperature of 93 K.", "author_names": [ "Tina Muller", "Joanna Skiba-Szymanska", "Andrey B Krysa", "Jan Huwer", "Martin Felle", "M Anderson", "R Mark Stevenson", "J Heffernan", "David A Ritchie", "Andrew J Shields" ], "corpus_id": 3571432, "doc_id": "3571432", "n_citations": 63, "n_key_citations": 0, "score": 0, "title": "A quantum light emitting diode for the standard telecom window around 1,550 nm", "venue": "Nature Communications", "year": 2018 }, { "abstract": "We demonstrate experimental results based on time resolved photoluminescence spectroscopy to determine the oscillator strength (OS) and the internal quantum efficiency (IQE) of InGaAs quantum dots (QDs) Using a strain reducing layer (SRL) these QDs can be employed for the manufacturing of single photon sources (SPS) emitting in the telecom O Band. The OS and IQE are evaluated by determining the radiative and non radiative decay rate under variation of the optical density of states at the position of the QD as proposed and applied in J. Johansen et al. Phys. Rev. B 77, 073303 (2008) for InGaAs QDs emitting at wavelengths below 1 mm. For this purpose, we perform measurements on a QD sample for different thicknesses of the capping layer realized by a controlled wet chemical etching process. From numeric modelling the radiative and nonradiative decay rates dependence on the capping layer thickness, we determine an OS of 24.6 3.2 and a high IQE of about (85 10) for the long wavelength InGaAs QDs. Introduction Semiconductor quantum dots (QDs) are well established solid state nanocrystalline structures that can be used as close to ideal two level quantum emitters applicable for instance in quantum communication [1, 2, 3] or quantum computing [4, 5] In recent years, performance of singlephoton emission based on InGaAs QDs could be pushed towards the physical limits for instance in terms of photon indistinguishability up to 99.7% [6] for QD emitting in the 930 950 nm range. Moreover, by material engineering the range of applications could be extended to the telecom O band at 1.3 mm [7, 8, 9, 10] which enables long distance fiber based quantum communication [11] A very promising way to achieve the required redshift of QD emission is the introduction of a strain reducing layer of lower Indium content on top of the QD layer [12] maintaining the high quality of emission in terms of multi photon suppression [9] An additional advantage of this technology route is the usage of a mature and well established GaAs based technology platform which facilitates the fabrication of advanced quantum light sources with enhanced photon extraction efficiency [13, 14, 15] and the possibility of spectral fine tuning by external strain fields [16] The QDs used in this work have been carefully optimized for the manufacturing of single photon sources emitting in a wavelength range around 1.3 mm at temperatures up to 40 K as detailed in previously published works [15, 16, 17] An important intrinsic property of any QD emitter is the internal quantum efficiency (IQE) which describes the ratio of quantum conversion from exciton formation into single photon emission. The IQE plays a major role in the total quantum efficiency of a fully processed device and directly impacts the photon extraction efficiency being a key parameter of quantum light sources. Thus, knowing and increasing the IQE is crucial for device optimization. Another important QD parameter is the oscillator strength (OS) of the optical transition. The OS is directly related to the radiative decay time of the emitter and determines the light matter coupling strength of QD devices using effects of cavity quantum electrodynamics [18] The exciton decay dynamics and IQE of In(Ga)As QDs emitting in the 920 to 1030 nm range have been experimentally examined by several groups [19, 20, 21, 22] with a method introduced by Johansen et al. [19] which allows for a direct measurement of the QD properties without being influenced by QD density or relying on assumptions based on theoretical considerations of the exciton radius and the dimensions of the QDs [23, 24] This method was also used to investigate an InGaAs quantum dot quantum well system [25] So far however, to our best knowledge, no such measurements have been performed on InGaAs QDs emitting in the telecom O band, so that reliable information on their IQE has not been available. In order to determine the IQE and OS of telecom wavelength InGaAs QDs their total decay rate G(o, z) at a frequency o and at z position below the sample surface is determined experimentally. The associated decay rate is given by the following relation: G(o, z) Gnrad(o) Grad (o) r(o,z) rhom(o) (1) where Gnrad(o) represents the nonradiative decay rate and Grad (o) is the radiative decay in a homogeneous medium, r(o, z) is the projected local density of states (LDOS) divided by the LDOS in a homogenous medium rhom(o) (the GaAs surrounding the QD) The total decay rate G(o, z) in dependance from z can be measured experimentally by means of time resolved micro photoluminescence (mPL) under variation of the capping layer thickness of the QD sample. Subsequently, the experimental components Grad(o) and Gnrad hom (o) are obtained by fitting parameters of a curve that has been derived from simulated values of the LDOS in dependance from z to the experimental data. The IQE can then be calculated as: IQE Grad hom Gnrad+Grad hom (2) and the OS can easily be derived from fosc(o) 6mee0pc0 3 q2no2 Grad (o) (3) where the electron mass me, the vacuum permittivity e0, the vacuum speed of light c0, the elementary charge q and the refractive index n of the surrounding GaAs is given [9] Sample Preparation The purpose of this work is to obtain a quantitative understanding of 1.3 mm InGaAs QDs, which were optimized for the development of quantum light sources emitting in the telecom Oband, in terms of their IQE and the OS. Using metal organic chemical vapor deposition (MOCVD) the corresponding sample was prepared in the following way. First, a 300 nm GaAs buffer is grown on n doped GaAs (100) substrate and followed by 1 mm thick Al0.90Ga0.10As layer. Then a 2 mm thick GaAs layer and another 100 nm thick Al0.90Ga0.10As layer is deposited. These three layers are originally designed as sacrificial layers to be removed during a postgrowth flip chip processing, as described in more detailed way in Refs. [15, 16] The final 879 nm thick layer of GaAs formerly designed to function as active device membrane includes a single InGaAs QD layer together with the SRL. The QD layer with a density of 5x10 cm is located 637 nm above the second etch stop layer and is formed by 1.5 monolayers of In0.7Ga0.3As followed by GaAs flush corresponding to a nominal thickness of half a monolayer. The subsequent 5.5 nm thick InGaAs SRL has a gradual decrease of the In content from 30% to 10% over the first 3.5 nm. This layer is followed by a GaAs capping layer with a thickness of 236 nm. An overview of the whole sample structure is given in Fig. 1(a) Further information on the QD growth and optimization can be found in the supplementary information. In order to vary the thickness of the caping layer as required for extracting the radiative and non radiative emission rate of the QDs the grown sample was prepared as described in the following. First, the surface of the sample was cleaned thoroughly and the photo resist AZ 701 MIR was applied using spin coating. UV lithography was used to pattern the surface with several slim rectangular structures to form a height reference to determine the capping layer thickness after the upcoming etching process. The sample was cut into 25 pieces to undergo wet chemical etching after thorough cleaning with isopropanol. The etching solution [26] was prepared with the following ingredients: Hydrobromic acid (HBr) hydrogen peroxide (H2O2) and water (H2O) in a volumetric ratio of 2:1:60. The solution was continuously agitated with a magnetic stirrer and left to rest for 600 seconds after adding the H2O2. The etching rate had been previously determined to be 0.5 nm/s by etching and measuring a set of test sample pieces of GaAs. The 25 pieces were put together into the solution and subsequently removed piece after piece after a set time interval to etch away the desired amount of GaAs capping and put into clean water to stop the etching process. The remaining thickness of the GaAs separating the QD layer from the sample surface was determined with comparative measurement in a stylus profiler and an atomic force microscope (AFM) setup. Both measurements agree within a margin of less than 10 nanometers. Because of local deviations in the etching rate the exact position of the photoluminescence lifetime measurement is later marked on an optical microscopic image and the local top GaAs layer thickness remeasured via AFM. These values, as given in Fig. 1(b) are used in later analysis of the mPL data. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 0 50 100 150 200 250 (b) D is ta n c e Q D s u rf a c e n m", "author_names": [ "Jan Grosse", "Pawel Mrowinski", "Nicole Srocka", "Stephan Reitzenstein" ], "corpus_id": 235390573, "doc_id": "235390573", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Quantum efficiency and oscillator strength of InGaAs quantum dots for single photon sources emitting in the telecommunication O band", "venue": "Applied Physics Letters", "year": 2021 }, { "abstract": "Quantum communication networks are formed of secure links, where information can be transmitted with security guaranteed by the quantum nature of light. An essential building block of such a network is a source of single photons and entangled photon pairs, compatible with the low loss fibre telecom window around 1550 nm. Previous work based on semiconductor quantum dots (QDs) colour centres in diamond and single atoms has been limited by emission wavelengths unsuitable for long distance applications. Efforts have been made to use standard gallium arsenide based QDs by extending their operating wavelength range, however, electrically driven quantum light emission from quantum dots in this telecommunication window has not yet been demonstrated. In this work, indium phosphide based QD devices have been developed to address this problem. The industry favoured growth method, metalorganic vapour phase epitaxy (MOVPE) has been used to create droplet QDs with low fine structure splitting (FSS) This growth scheme allows us to produce the first optoelectronic devices for single and entangled photon emission in the 1550 nm telecom window. We show single photon emission with multi photon events suppressed to 0.11+ 0.02. Furthermore, we obtain entangled light from the biexciton cascade with a maximum fidelity of 0.87+ 0.04 which is sufficient for error correction protocols. We also show extended device operating temperature up to 93 K, allowing operation with liquid nitrogen or simple closed cycle coolers. Our device can be directly integrated with existing long distance quantum communication, cryptography and quantum relay systems providing a new platform for developing quantum networks.", "author_names": [ "Tina Muller", "Joanna Skiba-Szymanska", "Andrey B Krysa", "Jan Huwer", "Martin Felle", "Matthew Anderson", "Mark Stevenson", "J Heffernan", "David A Ritchie", "Andrew J Shields" ], "corpus_id": 139779511, "doc_id": "139779511", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A quantum light emitting diode for the standard telecom window around 1550 nm (Conference Presentation)", "venue": "Advances in Photonics of Quantum Computing, Memory, and Communication XII", "year": 2019 }, { "abstract": "The coherent manipulation of the frequency of single photons is an important requirement for future quantum network technologies. It allows, for instance, quantum systems emitting in the visible range to be connected to the telecommunication wavelengths, thus extending the communication distances. Here we report on quantum frequency conversion of memory compatible narrow bandwidth photons at 606 nm to the telecom C band at 1552 nm. The 200 ns long photons, compatible with praseodymium based solid state quantum memories, are frequency converted using a single step difference frequency generation process in a periodically poled lithium niobate waveguide. We characterize the noise processes involved in the conversion and, by applying strong spectral filtering of the noise, we demonstrate high signal to noise ratio conversion at the single photon level (SNR>100, for a mean input photon number per pulse of 1) We finally observe that a memory compatible heralded single photon with a bandwidth of 1.8 MHz, obtained from a spontaneous parametric down conversion pair source, still shows a strong non classical behavior after conversion. We first demonstrate that correlations between heralding and converted heralded photons stay in the non classical regime. Moreover, we measure the heralded autocorrelation function of the heralded photon using the converter device as a frequency domain beam splitter, yielding a value of 0.19+ 0.07. The presented work represents a step towards the connection of several quantum memory systems emitting narrowband visible photons to the telecommunication wavelengths.", "author_names": [ "N Maring", "Dario Lago-Rivera", "Andreas Lenhard", "Georg Heinze", "Hugues de Riedmatten" ], "corpus_id": 102483260, "doc_id": "102483260", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Quantum frequency conversion of memory compatible single photons from 606 nm to the telecom C band", "venue": "", "year": 2018 } ]

[ { "abstract": "The new possibilities of self sustained oscillations of acoustoelectric and photoelectric voltages accompanied by surface acoustic wave and light self modulations in layered semiconductor piezoelectric and metal dielectric semiconductor structures with relaxation that we have discovered are presented with a view of sensing of physical and chemical environmental parameters and measurement of semiconductor electronic parameters. It gives principal methods to improve sensitivity and precision because the frequency of the self sustained oscillation or self modulation /spl Omega/ is expressed in terms of the charge discharge relaxation time /spl tausub s/ of the metal piezoelectric semiconductor or metal dielectric semiconductor structures. The frequency of self sustained oscillations /spl Omega/ allows relaxation time /spl tausub s/ to be determined directly. This connection between /spl Omega/ and /spl tausub s/ can successfully be used in physical and chemical sensors with frequency output and may be a basis investigations of semiconductor parameters such as surface states' parameters and their spectroscopy properties. It is the great interest because of in the precise sensors and investigation methods we use self organization processes in which the frequency of electrical signal can be easily measured with high precision and it gives high sensitivity.<ETX>", "author_names": [ "Vladimir Vyun" ], "corpus_id": 111177604, "doc_id": "111177604", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Sensing and measurement with self sustained acoustoelectric and photoelectric oscillations in structures with relaxation", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "In this paper a method is presented to impose a desired periodic excitation signal on the input of a nonlinear system using an arbitrary waveform generator. It is illustrated that this technique has many applications, like a linearity check of an unknown system and the measurement of the harmonic distortion.<ETX>", "author_names": [ "Frank Louage", "Joannes Schoukens", "Yves Rolain" ], "corpus_id": 110290793, "doc_id": "110290793", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "Generation of computer controlled excitations and its application to the detection and measurement of harmonic distortions", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "Fuzzy techniques can represent a global resource for intelligent instrumentation: this paper shows how a totally fuzzy approach can be proposed which is able to deal with 1 D and 2 D measurement data. Focussing on the task of data pre processing, we describe a family of rule based fuzzy operators and their capability of addressing some important pre processing tasks such as filtering and feature extraction. Application examples to both the cases of 1 D and 2 D data are presented.<ETX>", "author_names": [ "Fabrizio Russo", "Giovanni Ramponi" ], "corpus_id": 61204286, "doc_id": "61204286", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "A totally fuzzy approach to multisensor instrumentation: pre processing techniques", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "Testing an electronic circuit is a vital part of its overall design and fabrication process. This problem is even going to be more critical with technology improvements and with the coexistence on a chip of analog and digital components. In fact the testing of mixed signal microsystems is very difficult compared to digital only devices. They do not lend themselves to earlier and simpler test routines. The entire mixed signal segment is hampered by the lack of design for testability methodologies and tools. In this field the concept of analog circuit testability is of fundamental importance. The aim of this work is to present a new symbolic approach for testability measurement of analog networks. The new method presents noteworthy advantages from a computational point of view with respect to previous techniques. In fact it does not require the computation of the sensitivities of the network functions but it is based only on the study of the network function symbolic coefficients. The new approach allows also the formulation of simple necessary conditions for maximum testability based only on the order of the network functions.<ETX>", "author_names": [ "A Liberatore", "Stefano Manetti", "Maria Cristina Piccirilli" ], "corpus_id": 57892154, "doc_id": "57892154", "n_citations": 36, "n_key_citations": 1, "score": 0, "title": "A new efficient method for analog circuit testability measurement", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "This paper presents a position measuring method and its applications to human interface. It is based on the principle of ultrasonic position measurement by phase difference. In conventional method, position is computed with the absolute distance between sender and receiver, on the other hand, in our method, it is computed with the phase difference between the waves received by a pair of receivers. Any kinds of motor actions of users is available to screen pointing by the device, then it allows computer users various pointing styles including \"mouse like\" and \"pen like\" ones. Firstly, the principle and the formulae of ultrasonic position measurement by phase difference are introduced. Secondly, trial construction of the pointing system is described, and performance of the pointing system is investigated. Finally some examples of pointing devices with various pointing styles are realized, and experiments on the efficiency of pointing tasks with computer users are carried out to conclude that the pointing system is suitable for practical use.<ETX>", "author_names": [ "H Nonaka", "Tsutomu Da-te" ], "corpus_id": 110398477, "doc_id": "110398477", "n_citations": 24, "n_key_citations": 1, "score": 0, "title": "Ultrasonic position measurement and its applications to human interface", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "The success of demand side energy control in industries, mines and commercial buildings depends on factors like the energy sensitivity and awareness of the organisation as well as an accurate and effective measurement and monitoring of its electrical energy consumption. Demand side energy control also forms an important part in the research programs of many research organisations. Reliable data on energy consumption is therefore imperative for effective research in this field, as well as for the successful implementation of demand side management. Traditional load research instrumentation has involved intrusive techniques that require the installation of sensors on each of the individual components of the total load. A non intrusive appliance load monitor is proposed in this paper to determine the energy consumption of individual appliances turning on or off or operating under continuously varying load conditions. This monitoring system, which is implemented by network pattern identification technology, is based on detailed analysis of the current and voltage of the total load, as measured at the interface of the power source. The approach has been developed to simplify the collection of energy consumption data by utilities, but also has other applications. It is called nonintrusive to contrast it with previous techniques for gathering appliance data, which require placing sensors on individual appliances, and hence an intrusion onto the energy consumer's properly.<ETX>", "author_names": [ "J G Roos", "I E Lane", "Elizabeth C Botha", "Gerhard Petrus Hancke" ], "corpus_id": 110106465, "doc_id": "110106465", "n_citations": 82, "n_key_citations": 4, "score": 0, "title": "Using neural networks for non intrusive monitoring of industrial electrical loads", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "In this paper we describe a method for measuring three dimensional shape of specular polyhedron by using an M array coded light source. Determination of a shape of specular surface is important especially for industrial applications. However, owing to specular reflection, it is difficult to measure the shape of specular surfaces by applying the methods for diffusing surfaces. We reconstruct the shape of specular objects from the image of M array coded light source observed after being reflected by the object. Using the \"window property\" of M array, the correspondence is found between a point on the image of reflected light source and a point on light source. By assuming that the surface is locally a plane, normal vectors of the surface are determined from the correspondence, and three dimensional shape of the surface is reconstructed. This method enables us to measure the shape of specular polyhedron by using a simple equipment. The method was tested for a polyhedron of 10 cm of each side, 50 cm apart from the camera. The shape of the polyhedron was reconstructed correctly. The precision of the measurement was about 1 mm.<ETX>", "author_names": [ "Hiroshi Hoshino", "Kazuo Yano", "Senya Kiyasu", "Sadao Fujimura" ], "corpus_id": 122576440, "doc_id": "122576440", "n_citations": 31, "n_key_citations": 1, "score": 0, "title": "Measurement of the 3 D shape of specular polyhedrons using an M array coded light source", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "The DMM card manufactured by MetraByte USA and an IBM PC compatible computer have been used for power distribution monitoring. The DMM (digital multimeter) card belongs to the group of VTS virtual instrumentation systems. It converts the IBM PC compatible computer into a powerful instrumentation system. This system has been hooked onto the busbars of a multi cubicle switchboard, which is directly connected to the distribution power transformer outside the building of the department of electrical engineering.<ETX>", "author_names": [ "K Korzeniowski" ], "corpus_id": 110392577, "doc_id": "110392577", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The use of DMM computer instrumentation system for power distribution monitoring and energy management", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "Fuzzy techniques can represent a comprehensive framework for intelligent instrumentation which deals with multisensory input data. Addressing the task of data fusion, this paper shows how flexible processing strategies can be implemented by resorting to a fuzzy approach. The general structure of a fuzzy system for information fusion is described and the adoption of different classes of fuzzy aggregation connectives discussed. Examples of application to both cases of 1 D and 2 D data are presented.<ETX>", "author_names": [ "Fabrizio Russo" ], "corpus_id": 61321131, "doc_id": "61321131", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A totally fuzzy approach to multisensor instrumentation: estimation through data fusion", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 }, { "abstract": "Methods of Alternating Noise Canceling (ANC) were previously developed for the optical instrumentation: one using a dual photo sensor and another using a single photo sensor that could cancel normal mode noise (NMN) on a transmission line, even if the noise was equal status noise. A method using a sensor with a sensordummy resistance was also previously developed using ANC method against NMN not only on a transmission line but also on a sensor line. In this case, the sensordummy resistance had to be adjusted to a suitable averaging value against the changing impedance of the photo sensor. A new method of ANC is developed using a photo sensor and a dual sensor dummy i.e. an inverse connected sensordummy. This method doesn't need adjustment for any dummy resistance.<ETX>", "author_names": [ "Katsutoshi Mine", "N Kubota", "Fumio Morimoto", "Mizuho Sanada", "L Ne" ], "corpus_id": 111010831, "doc_id": "111010831", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An optical instrumentation using dual sensor dummy against noises", "venue": "Conference Proceedings. 10th Anniversary. IMTC/94. Advanced Technologies in I M. 1994 IEEE Instrumentation and Measurement Technolgy Conference (Cat. No.94CH3424 9)", "year": 1994 } ]

[ { "abstract": "CONSPECTUS: Atomic crystals of two dimensional materials consisting of single sheets extracted from layered materials are gaining increasing attention. The most well known material from this group is graphene, a single layer of graphite that can be extracted from the bulk material or grown on a suitable substrate. Its discovery has given rise to intense research effort culminating in the 2010 Nobel Prize in physics awarded to Andre Geim and Konstantin Novoselov. Graphene however represents only the proverbial tip of the iceberg, and increasing attention of researchers is now turning towards the veritable zoo of so called \"other 2D materials\" They have properties complementary to graphene, which in its pristine form lacks a bandgap: MoS2, for example, is a semiconductor, while NbSe2 is a superconductor. They could hold the key to important practical applications and new scientific discoveries in the two dimensional limit. This family of materials has been studied since the 1960s, but most of the research focused on their tribological applications: MoS2 is best known today as a high performance dry lubricant for ultrahigh vacuum applications and in car engines. The realization that single layers of MoS2 and related materials could also be used in functional electronic devices where they could offer advantages compared with silicon or graphene created a renewed interest in these materials. MoS2 is currently gaining the most attention because the material is easily available in the form of a mineral, molybdenite, but other 2D transition metal dichalcogenide (TMD) semiconductors are expected to have qualitatively similar properties. In this Account, we describe recent progress in the area of single layer MoS2 based devices for electronic circuits. We will start with MoS2 transistors, which showed for the first time that devices based on MoS2 and related TMDs could have electrical properties on the same level as other, more established semiconducting materials. This allowed rapid progress in this area and was followed by demonstrations of basic digital circuits and transistors operating in the technologically relevant gigahertz range of frequencies, showing that the mobility of MoS2 and TMD materials is sufficiently high to allow device operation at such high frequencies. Monolayer MoS2 and other TMDs are also direct band gap semiconductors making them interesting for realizing optoelectronic devices. These range from simple phototransistors showing high sensitivity and low noise, to light emitting diodes and solar cells. All the electronic and optoelectronic properties of MoS2 and TMDs are accompanied by interesting mechanical properties with monolayer MoS2 being as stiff as steel and 30x stronger. This makes it especially interesting in the context of flexible electronics where it could combine the high degree of mechanical flexibility commonly associated with organic semiconductors with high levels of electrical performance. All these results show that MoS2 and TMDs are promising materials for electronic and optoelectronic applications.", "author_names": [ "Dominik S Lembke", "Simone Bertolazzi", "Andras Kis" ], "corpus_id": 17679937, "doc_id": "17679937", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "Single Layer MoS 2 Electronics Published as part of the Accounts of Chemical Research special issue \" 2 D Nanomaterials beyond Graphene \"", "venue": "", "year": 2015 }, { "abstract": "Structuring materials with atomic precision is the ultimate goal of nanotechnology and is becoming increasingly relevant as an enabling technology for quantum electronics/spintronics and quantum photonics. Here, we create atomic defects in monolayer MoS2 by helium ion beam lithography with a spatial fidelity approaching the single atom limit in all three dimensions. Using low temperature scanning tunneling microscopy (STM) we confirm the formation of individual point defects in MoS2 upon He ion bombardment and show that defects are generated within 9 nm of the incident helium ions. Atom specific sputtering yields are determined by analyzing the type and occurrence of defects observed in high resolution STM images and compared with Monte Carlo simulations. Both theory and experiment indicate that the He ion bombardment predominantly generates sulfur vacancies.", "author_names": [ "Elmar Mitterreiter", "Bruno Schuler", "Katherine A Cochrane", "Ursula Wurstbauer", "Alexander Weber-Bargioni", "Christoph Kastl", "Alexander W Holleitner" ], "corpus_id": 218506196, "doc_id": "218506196", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Atomistic positioning of defects in helium ion treated single layer MoS2.", "venue": "Nano letters", "year": 2020 }, { "abstract": "Transition metal dichalcogenides (TMDs) have emerged in recent years as a special group of two dimensional materials and have attracted tremendous attention. Among these TMD materials, molybdenum disulfide (MoS2) has shown promising applications in electronics, photonics, energy, and electrochemistry. In particular, the defects in MoS2 play an essential role in altering the electronic, magnetic, optical, and catalytic properties of MoS2, presenting a useful way to engineer the performance of MoS2. The mechanisms by which lattice defects affect the MoS2 properties are unsettled. In this work, we reveal systematically how lattice defects and substrate interface affect MoS2 electronic structure. We fabricated single layer MoS2 by chemical vapor deposition and then transferred onto Au, single layer graphene, hexagonal boron nitride, and CeO2 as substrates and created defects in MoS2 by ion irradiation. We assessed how these defects and substrates affect the electronic structure of MoS2 by performing X ray photoelectron spectroscopy, Raman and photoluminescence spectroscopies, and scanning tunneling microscopy/spectroscopy measurements. Molecular dynamics and first principles based simulations allowed us to conclude the predominant lattice defects upon ion irradiation and associate those with the experimentally obtained electronic structure. We found that the substrates can tune the electronic energy levels in MoS2 due to charge transfer at the interface. Furthermore, the reduction state of CeO2 as an oxide substrate affects the interface charge transfer with MoS2. The irradiated MoS2 had a faster hydrogen evolution kinetics compared to the as prepared MoS2, demonstrating the concept of defect controlled reactivity in this phase. Our findings provide effective probes for energy band and defects in MoS2 and show the importance of defect engineering in tuning the functionalities of MoS2 and other TMDs in electronics, optoelectronics, and electrochemistry.", "author_names": [ "Yuwei Chen", "Shengxi Huang", "Xiang Ji", "Kiran Kumar Adepalli", "Kedi Yin", "Xi Ling", "Xinwei Wang", "Jianming Xue", "Mildred S Dresselhaus", "Jing Kong", "Bilge Yildiz" ], "corpus_id": 206718457, "doc_id": "206718457", "n_citations": 104, "n_key_citations": 0, "score": 0, "title": "Tuning Electronic Structure of Single Layer MoS2 through Defect and Interface Engineering.", "venue": "ACS nano", "year": 2018 }, { "abstract": "Abstract The buckling behavior of a single layer MoS2 (SLMoS2) sheet with defects under uniaxial compression is investigated with molecular simulation in the present paper. Five typical defects are introduced to estimate the instability characteristics of defective MoS2 sheet. The buckling responses, including the critical strain and geometric morphology, influenced by defect type, stain rate, defect density and so on, are comprehensively explored. It is found that different type of defects results in reduction of the bending modulus to some different extent. Compared with the other three post buckling morphologies, the first typical geometric morphology show the biggest difference between the defect free and defective SLMoS2 sheets. It seems possible to realize our desired morphology in flexible electronics by proper preparing different kinds of defects. The finding in the present paper should be useful for the promising design of flexible optoelectronic devices and soft bioelectronics.", "author_names": [ "Yao Li", "Peijian Chen", "Cun Zhang", "Juan Peng", "Feng Gao", "Hao Liu" ], "corpus_id": 139597605, "doc_id": "139597605", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Molecular dynamics simulation on the buckling of single layer MoS2 sheet with defects under uniaxial compression", "venue": "Computational Materials Science", "year": 2019 }, { "abstract": "Heterojunctions of semiconductors and metals are the fundamental building blocks of modern electronics. Coherent heterostructures between dissimilar materials can be achieved by composition, doping, or heteroepitaxy of chemically different elements. Here, we report the formation of coherent single layer 1H 1T MoS2 heterostructures by mechanical exfoliation on Au(111) which are chemically homogeneous with matched lattices but show electronically distinct semiconducting (1H phase) and metallic (1T phase) character, with the formation of these heterojunctions attributed to a combination of lattice strain and charge transfer. The exfoliation approach employed is free of tape residues usually found in many exfoliation methods and yields single layer MoS2 with millimeter (mm) size on the Au surface. Raman spectroscopy, X ray photoelectron spectroscopy (XPS) atomic force microscopy (AFM) scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) have collectively been employed to elucidate the structural and electronic properties of MoS2 monolayers on Au substrates. Bubbles in the MoS2 formed by the trapping of ambient adsorbates beneath the single layer during deposition, have also been observed and characterized. Our work here provides a basis to produce two dimensional heterostructures which represent potential candidates for future electronic devices.", "author_names": [ "Fanglue Wu", "Zhuotong Liu", "Nathaniel Hawthorne", "Michael Chandross", "Quentarius Moore", "Nicolas Argibay", "John F Curry", "James D Batteas" ], "corpus_id": 227244623, "doc_id": "227244623", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Formation of Coherent 1H 1T Heterostructures in Single Layer MoS2 on Au(111)", "venue": "ACS nano", "year": 2020 }, { "abstract": "While two dimensional (2D) van der Waals (vdW) layered materials are promising channel materials for wearable electronics and energy efficient field effect transistors (FETs) large hysteresis and large subthreshold swing induced by either dangling bonds at gate oxide dielectrics and/or trap molecules in bubbles at vdW interface are a serious drawback, hampering implementation of the 2D material based FETs in real electronics. Here, we report a monolayer MoS2 FET with near zero hysteresis reaching 0.15% of the sweeping range of the gate bias, a record value observed so far in 2D FETs. This was realized by squeezing the MoS2 channel between top h BN layer and bottom h BN gate dielectrics and further removing the trap molecules in bubbles at the vdW interfaces via post annealing. By segregating the bubbles out to the edge of the channel, we also obtain excellent switching characteristics with a minimum subthreshold swing of 63 mV/dec, an average subthreshold slope of 69 mV/dec for a current range of four orders of magnitude at room temperature, and a high on/off current ratio of 108 at a small operating voltage <1 V) Such a near zero hysteresis and a near ideal subthreshold limit originate from the reduced trap density of ~5.2 x 109 cm 2 eV 1, a thousand times smaller than previously reported values.", "author_names": [ "Quoc An Vu", "Sidi Fan", "Sang Hyup Lee", "Min-Kyu Joo", "Woo Jong Yu", "Young Hee Lee" ], "corpus_id": 115604074, "doc_id": "115604074", "n_citations": 55, "n_key_citations": 1, "score": 0, "title": "Near zero hysteresis and near ideal subthreshold swing in h BN encapsulated single layer MoS2 field effect transistors", "venue": "", "year": 2018 }, { "abstract": "Phase transitions in 2D materials, such as MoS2, result in drastic changes in the physical properties of the material. A change in the phase of MoS2 from 2H to 1T transforms it from a semiconductor to conductor, thus broadening its potential applications in electronics. The structural transformation associated with the phase change may significantly affect the mechanical properties. Here we statistically characterized the elastic modulus and fracture strength of phase changed single layer MoS2 sheets using the atomic force microscopy (AFM) nanoindentation technique. MoS2 sheets were subjected to lithium intercalation, which transformed them from the 2H phase to the 1T phase. The transformed sheets were again annealed to make a partially phase changed sample. The elastic modulus and fracture strength of 1T phase MoS2 were about 50% lower than those of 2H phase MoS2. Annealing of the 1T phase MoS2 sheet resulted in a good recovery of the mechanical properties, up to 90% of those of the original 2H phase MoS2. This result was attributed to a mixture of phases in the annealed product, and the ratio of the phases was evaluated spectroscopically. Interestingly, while the fracture strengths differed for the three phases, their average fracture strains were quite similar, suggesting that the overall structure of the material maintained its integrity during the phase transition process.", "author_names": [ "Jaehyuck Jung", "Hunyoung Bark", "Doyoung Byun", "Changgu Lee", "Dae-Hyun Cho" ], "corpus_id": 189163827, "doc_id": "189163827", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Mechanical characterization of phase changed single layer MoS 2 sheets", "venue": "2D Materials", "year": 2019 }, { "abstract": "Atomically thin Transition metal dichalcogenides (TMDs) have come into the spotlight in optoelectronics thanks to their outstanding physical properties [1,2] In single layer (1L) TMDs strong quantum confinement effects cause a weak screening of Coulomb, so that the excitons created by photo excitation have large binding energy, up to several hundred meVs [3] While the steady state properties of TMDCs have been studied in detail by linear optical techniques, the recent application of time resolved nonlinear spectroscopy (mainly ultrafast pump probe) has enabled the study of excited state dynamics on femtosecond timescales [4] opening up questions about the mechanisms of exciton relaxations and exciton exciton interactions.", "author_names": [ "Margherita Maiuri", "Stefano Dal Conte", "Mattia Russo", "Junjia Wang", "Giancarlo Soavi", "Dumitru Dumcenco", "Andras Kis", "Malte Selig", "Sandra Khun", "Marten Richter", "Andreas Knorr", "Andrea C Ferrari", "Giulio Cerullo" ], "corpus_id": 204819490, "doc_id": "204819490", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Excitonic Effects in Single Layer MoS2 Probed by Broadband Two Dimensional Electronic Spectroscopy", "venue": "2019 Conference on Lasers and Electro Optics Europe European Quantum Electronics Conference (CLEO/Europe EQEC)", "year": 2019 }, { "abstract": "Logic circuits and the ability to amplify electrical signals form the functional backbone of electronics along with the possibility to integrate multiple elements on the same chip. The miniaturization of electronic circuits is expected to reach fundamental limits in the near future. Two dimensional materials such as single layer MoS(2) represent the ultimate limit of miniaturization in the vertical dimension, are interesting as building blocks of low power nanoelectronic devices, and are suitable for integration due to their planar geometry. Because they are less than 1 nm thin, 2D materials in transistors could also lead to reduced short channel effects and result in fabrication of smaller and more power efficient transistors. Here, we report on the first integrated circuit based on a two dimensional semiconductor MoS(2) Our integrated circuits are capable of operating as inverters, converting logical \"1\" into logical \"0\" with room temperature voltage gain higher than 1, making them suitable for incorporation into digital circuits. We also show that electrical circuits composed of single layer MoS(2) transistors are capable of performing the NOR logic operation, the basis from which all logical operations and full digital functionality can be deduced.", "author_names": [ "Branimir Radisavljevic", "Michael Brian Whitwick", "Andras Kis" ], "corpus_id": 7161527, "doc_id": "7161527", "n_citations": 995, "n_key_citations": 6, "score": 0, "title": "Integrated circuits and logic operations based on single layer MoS2.", "venue": "ACS nano", "year": 2011 }, { "abstract": "Field effect transistors using ultrathin molybdenum disulfide (MoS(2) have recently been experimentally demonstrated, which show promising potential for advanced electronics. However, large variations like hysteresis, presumably due to extrinsic/environmental effects, are often observed in MoS(2) devices measured under ambient environment. Here, we report the origin of their hysteretic and transient behaviors and suggest that hysteresis of MoS(2) field effect transistors is largely due to absorption of moisture on the surface and intensified by high photosensitivity of MoS(2) Uniform encapsulation of MoS(2) transistor structures with silicon nitride grown by plasma enhanced chemical vapor deposition is effective in minimizing the hysteresis, while the device mobility is improved by over 1 order of magnitude.", "author_names": [ "Dattatray J Late", "Bin Liu", "H S S Ramakrishna Matte", "Vinayak P Dravid", "C N R Rao" ], "corpus_id": 36572816, "doc_id": "36572816", "n_citations": 790, "n_key_citations": 10, "score": 0, "title": "Hysteresis in single layer MoS2 field effect transistors.", "venue": "ACS nano", "year": 2012 } ]

[ { "abstract": "This paper presents a miniaturized gas sensing platform for rapid and ultrasensitive optical detection of methane gas by integrating the state of the art complementary metal oxide semiconductor compatible meta material absorber with a smart, porous metal organic framework (MOF) The implementation of methane gas detection relies on the integration between meta materials and MOF, where MOF functions as a gas trap to capture more gas into the meta material absorber. We have experimentally demonstrated an approximately 1,000 fold sensitivity enhancement by using this method. Furthermore, the investigation of the geometry dependent characteristics provides a way to further expand the scope of application, such as CO2, CO and SO2, etc.", "author_names": [ "Hong Zhou", "Dongxiao Li", "Xindan Hui", "Donglin Hu", "Xiaolei Chen", "Xianming He", "Xiaojing Mu" ], "corpus_id": 215723182, "doc_id": "215723182", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Metamaterial Gas Sensing Platform Based on Surface Enhanced Infrared Absorption", "venue": "2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS)", "year": 2020 }, { "abstract": "The presence of an excessive concentration of CO2 in the atmosphere needs to be curbed with suitable measures including the reduction of CO2 emissions at stationary point sources such as power plants through carbon capture technologies and subsequent conversion of the captured CO2 into non polluting clean fuels/chemicals using photo and/or electrocatalytic pathways. Porous materials have attracted much attention for carbon capture and in the recent past; they have witnessed significant advancements in their design and implementation for CO2 capture and conversion. In this context, the emerging trends in major porous adsorbents such as MOFs, zeolites, POPs, porous carbons, and mesoporous materials for CO2 capture and conversion are discussed. Their surface texture and chemistry, and the influence of various other features on their efficiency, selectivity, and recyclability for CO2 capture and conversion are explained and compared thoroughly. The scientific and technical advances on the material structure versus CO2 capture and conversion provide deep insights into designing effective porous materials. The review concludes with a summary, which compiles the key challenges in the field, current trends and critical challenges in the development of porous materials, and future research directions combined with possible solutions for realising the deployment of porous materials in CO2 capture and conversion.", "author_names": [ "Gurwinder Singh", "Jangmee Lee", "Ajay S Karakoti", "Rohan Bahadur", "Jiabao Yi", "Dongyuan Zhao", "Khalid Albahily", "Ajayan Vinu" ], "corpus_id": 218908378, "doc_id": "218908378", "n_citations": 77, "n_key_citations": 0, "score": 0, "title": "Emerging trends in porous materials for CO2 capture and conversion.", "venue": "Chemical Society reviews", "year": 2020 }, { "abstract": "Abstract CO2 direct air capture (DAC) has been increasingly discussed as a climate change mitigation option. Despite technical advances in the past decade, there are still misconceptions about DAC's current and long term costs as well as energy, water and area demands. This could undermine DAC's anticipated role in a neutral or negative greenhouse gas emission energy system, and influence policy makers. In this study, a literature review and techno economic analyses of state of the art DAC technologies are performed, wherein, DAC technologies are categorised as high temperature aqueous solutions (HT DAC) and low temperature solid sorbent (LT DAC) systems, from an energy system perspective. DAC capital expenditures, energy demands and costs have been estimated under two scenarios for DAC capacities and financial learning rates in the period 2020 to 2050. DAC system costs could be lowered significantly with commercialisation in the 2020s followed by massive implementation in the 2040s and 2050s, making them cost competitive with point source carbon capture and an affordable climate change mitigation solution. It is concluded that LT DAC systems are favourable due to lower heat supply costs and the possibility of using waste heat from other systems. CO2 capture costs of LT DAC systems powered by hybrid PV Wind battery systems for Moroccan conditions and based on a conservative scenario, without/with utilisation of free waste heat are calculated at 222/133, 105/60, 69/40 and 54/32 EUR/tCO2 in 2020, 2030, 2040 and 2050, respectively. These new findings could enhance DAC's role in a successful climate change mitigation strategy.", "author_names": [ "Mahdi Fasihi", "O V Efimova", "Christian Breyer" ], "corpus_id": 159399402, "doc_id": "159399402", "n_citations": 187, "n_key_citations": 5, "score": 1, "title": "Techno economic assessment of CO2 direct air capture plants", "venue": "Journal of Cleaner Production", "year": 2019 }, { "abstract": "Abstract The quest for producing cost effective and efficient adsorbents for CO2 capture has received enormous attention in recent times. Biomass derived porous carbons are considered to be the most preferred adsorbent materials for CO2 capture owing to their excellent textural properties, tunable porosity and low cost. Different type of activation processes including solid state activation possess generate appropriate morphology and other physico chemical properties in these materials which enable them to act as effective adsorbents for CO2 capture. In this review, the key scientific results from published literature have been consolidated and critical commentary has been provided to give a broad insight into the production of biochar and activated porous carbons and their application in CO2 capture. A thorough review of the mechanism of pyrolysis for cellulose, hemicellulose and lignin has been presented in detail. The ability of different activating agents to produce activated porous carbons has been discussed. A summary of the application of biochar and activated porous carbons for CO2 capture has been included. The review concludes with an overview of future outlook and potential research direction that could be undertaken for advancing the utilization of biomass derived porous carbon materials for applications including CO2 capture and energy storage.", "author_names": [ "Gurwinder Singh", "Kripal Singh Lakhi", "S Sil", "Sheshanath V Bhosale", "Khalid Al-Bahily", "Ajayan Vinu" ], "corpus_id": 140970302, "doc_id": "140970302", "n_citations": 124, "n_key_citations": 0, "score": 0, "title": "Biomass derived porous carbon for CO2 capture", "venue": "Carbon", "year": 2019 }, { "abstract": "Abstract Utilization is one of the prominent strategies for the management of hazardous industrial wastes like fly ash. As fossil based power is expected to remain a major source of global electricity supply in the coming years, the absence of effective management strategies will exacerbate the problem of fly ash waste in the environment. Global fly ash utilization rates remain low due to limited utilization opportunities outside the construction industry. This necessitates the development of new pathways for its utilization as a means of diverting it from landfills where it poses a significant threat to the environment. Carbon capture, utilization, and storage presents opportunities to utilize fly ash in various ways; as a capture material, as a medium for permanent CO2 storage via mineralization, and as a catalyst or catalyst support for CO2 utilization processes. This study reviews the different technologies through which fly ash and materials derived from fly ash are applied in the CO2 capture, utilization, and storage technology while highlighting some challenges and opportunities for further research and development.", "author_names": [ "Abdallah Dindi", "Dang Viet Quang", "Lourdes F Vega", "Enas Nashef", "Mohammad R M Abu-Zahra" ], "corpus_id": 135084406, "doc_id": "135084406", "n_citations": 99, "n_key_citations": 2, "score": 0, "title": "Applications of fly ash for CO2 capture, utilization, and storage", "venue": "", "year": 2019 }, { "abstract": "CO2 capture, utilization and storage has been recognized as a primary option to mitigate the issue of climate change caused by the utilization of fossil fuels. Several CO2 capture strategies have b", "author_names": [ "Chunfeng Song", "Qingling Liu", "Shuai Deng", "Hailong Li", "Yutaka Kitamura" ], "corpus_id": 115285123, "doc_id": "115285123", "n_citations": 107, "n_key_citations": 1, "score": 0, "title": "Cryogenic based CO2 capture technologies: State of the art developments and current challenges", "venue": "Renewable and Sustainable Energy Reviews", "year": 2019 }, { "abstract": "Abstract Carbon Capture and Storage is regarded as an important component in a portfolio of low carbon energy technologies for mitigating climate change. Absorption technologies are presently the most available and effective approach for post combustion CO2 capture. However, state of the art amine based absorption technologies incur intensive energy use, as high as 3 times the thermodynamic minimum, thus resulting in prohibitively high costs. Solvents are key to the performance of absorption technologies. Recently, a new class of solvents, phase change solvents, have attracted growing interest due to their potential to substantially reduce energy use for CO2 capture. Phase change solvents are homogeneous (single phase) solvents under normal conditions, but undergo a phase transition into a heterogenic (two phase) system, triggered by changes in polarity, hydrophilicity, ionic strength, or hydrogen bond strength to form a CO2 lean liquid phase and a CO2 enriched liquid or solid phase. This review paper first examines different mechanisms that trigger phase separations in solvents. A comprehensive list of phase change solvents reported in the recent literature, including those subject to chemically or thermally triggered phase changes, non aqueous or aqueous systems, and those forming either a CO2 enriched solid or a liquid phase are provided and their physiochemical properties for CO2 capture are discussed. Enabled by phase change solvents, different variants of CO2 absorption processes have been developed and tested in laboratory or pilot scales over the past ten years. The status of such emerging processes is summarized and their advantages and challenges for post combustion CO2 capture are reviewed and commented. Solvent properties such as CO2 loading capacity, lean and rich phase partition, desorption pressure, absorption kinetics, viscosity, stability, and volatility are critical for both CO2 capture performance and scalability. Gaps between state of the art and ideal solvents are analyzed, and insights into the research needs such as solvent structure property performance relations, computational solvent design, ideal vapor liquid equilibrium behavior, and integration of capture processes with post combustion emission sources are provided.", "author_names": [ "Shihan Zhang", "Yao Shen", "Lidong Wang", "Jianmeng Chen", "Yongqi Lu" ], "corpus_id": 116609991, "doc_id": "116609991", "n_citations": 86, "n_key_citations": 0, "score": 0, "title": "Phase change solvents for post combustion CO2 capture: Principle, advances, and challenges", "venue": "Applied Energy", "year": 2019 }, { "abstract": "Abstract Dramatic increase of CO2 emissions to sate the global carbon demand for chemicals, goods, and fuels has been regarded as one of the main contributors triggering global warming. Note that CO2 emissions are over the Earth's full capacity to assimilate carbons via the natural carbon cycle. In these respects, CO2 capture and sequestration have been considered as one of the strategic principles to cancel out CO2 release from the anthropogenic activities in line with the use of fossil fuels. Thus, it is desirable to develop the efficient CO2 sorptive materials that are economically viable. Among CO2 sorptive materials, biochar (i.e. porous carbon based materials) has been considered as one of the promising candidates. Indeed, a great deal of researches on biomass has been performed. Based on these rationales, this review laid great emphasis on informing the recent studies of activated biochars for CO2 adsorption, which were fabricated from various biomasses. Also, this review offered the up to date knowledge on the physicochemical properties of activated biochars in line with their synthesis procedures. Lastly, the effects of biochar properties on CO2 capture and separation was summarized with in depth assessment of the activated biochars.", "author_names": [ "Sungyup Jung", "Young-Kwon Park", "Eilhann E Kwon" ], "corpus_id": 149907490, "doc_id": "149907490", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "Strategic use of biochar for CO2 capture and sequestration", "venue": "Journal of CO2 Utilization", "year": 2019 }, { "abstract": "Abstract Calcium looping is regarded as an effective and viable way to address CO2 emissions. To overcome the loss in capacity problems of calcium based sorbents with the number of calcium looping cycles, a novel CaO/Ca12Al14O33 sorbent with a microtube like structure was prepared from carbide slag and Al(NO3)3*9H2O using paper fibre as a biotemplate. The CO2 capture performance and microstructure of the novel synthetic sorbent under calcium looping conditions were investigated. The results show that the utilization of the biotemplate is good to retain the high cyclic CO2 capture reactivity of the synthetic sorbent. Due to the unique hollow porous structure, the CO2 capture capacity of the synthetic sorbent containing 7.5 wt% Al2O3 retains 0.56 and 0.33 g/g after 30 cycles under mild and severe calcination conditions, respectively, which are 2.56 and 2.11 times higher than those of carbide slag under the same respective calcination conditions. With the presence of 10% steam in the carbonation atmosphere, the CO2 capture capacity of the synthetic sorbent retains 0.55 g/g under the severe calcination conditions after 10 cycles. The native hierarchical biostructure of paper fibre is preserved in the synthetic sorbent. CaO and Ca12Al14O33 are uniformly distributed in the synthetic sorbent, resulting in a high sintering resistance during multiple CO2 capture cycles. CO2 can penetrate through the microtube like structure of the synthetic sorbent from two directions, i.e. from the outer surface and inner surface. This phenomenon effectively enlarges the contact area between CO2 and CaO. The CaO/Ca12Al14O33 sorbent with a hollow porous structure by means of a biotemplate appears promising in the calcium looping technology for CO2 capture.", "author_names": [ "Xiaotong Ma", "Yingjie Li", "Xianyao Yan", "Wan Zhang", "Jianli Zhao", "Zeyan Wang" ], "corpus_id": 104393096, "doc_id": "104393096", "n_citations": 62, "n_key_citations": 0, "score": 0, "title": "Preparation of a morph genetic CaO based sorbent using paper fibre as a biotemplate for enhanced CO2 capture", "venue": "Chemical Engineering Journal", "year": 2019 }, { "abstract": "Abstract It is urgent to reduce the emission of carbon dioxide (CO2) into the atmosphere and thereby mitigate climate changes. To implement the industrial scenario of carbon capture and storage (CCS) there is a great need for the discovery or development of excellent solid CO2 sorbents with technological and economic feasibility. Lithium orthosilicate (Li4SiO4) has been identified as one of the most promising candidates for CO2 capture at high temperatures and has drawn worldwide research interests. In the last years, focusing on the ultimate goal of achieving a Li4SiO4 sorbent with excellent physicochemical performance for various industrial applications, extensive works have been conducted, including exploring suitable preparation methods, modeling analysis, various modifications for performance enhancement, optimization of operation conditions, granulation and their applications. This work summarizes the state of the art researches in the literature aiming at developments of Li4SiO4 sorbents for high temperature CO2 capture. The potential new development trends are also discussed in the current work.", "author_names": [ "Yingchao Hu", "Wenqiang Liu", "Yuandong Yang", "Mingyu Qu", "Hailong Li" ], "corpus_id": 106302176, "doc_id": "106302176", "n_citations": 67, "n_key_citations": 0, "score": 0, "title": "CO2 capture by Li4SiO4 sorbents and their applications: Current developments and new trends", "venue": "Chemical Engineering Journal", "year": 2019 } ]

[ { "abstract": "Power Semiconductor Devices Key Components for Efficient Electrical Energy Conversion Systems. Semiconductor Properties. pn Junctions. Short introduction to power device technology. pin Diodes. Schottky Diodes. Bipolar Transistors. Thyristors. MOS Transistors. IGBTs. Packaging and Reliability of Power Devices. Destructive Mechanisms in Power Devices. Power Device Induced Oscillations and Electromagnetic Disturbances. Power Electronic Systems. Appendix. Index.", "author_names": [ "Josef Lutz", "Heinrich Dr Schlangenotto", "Uwe Scheuermann", "Rik W De Doncker" ], "corpus_id": 106910905, "doc_id": "106910905", "n_citations": 344, "n_key_citations": 44, "score": 1, "title": "Semiconductor Power Devices: Physics, Characteristics, Reliability", "venue": "", "year": 2011 }, { "abstract": "", "author_names": [ "Leo Lorenz" ], "corpus_id": 67874714, "doc_id": "67874714", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Semiconductor Power Devices: Physics, Characteristics, Reliability [Book Review]", "venue": "IEEE Power Electronics Magazine", "year": 2019 }, { "abstract": "", "author_names": [ "Philip Hower" ], "corpus_id": 543642, "doc_id": "543642", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Semiconductor Power Devices, Physics, Characteristics, Reliability, by Josef Lutz, Heinrich Schlangenotto, Uwe Scheuermann, and Rik De Doncker, Springer Verlag, Berlin Heidelberg (2011) ISBN 978 3 642 11124 2", "venue": "Microelectron. Reliab.", "year": 2012 }, { "abstract": "The status and challenges in the development of GaN power devices are reviewed. At present, normally off gate injection transistors (GITs) on Si are commercially available. The updated structure known as a hybrid drain embedded GIT provides superior reliability that contributes to the stable operation of compact power switching systems with high efficiency. The fabricated vertical GaN transistor on GaN as a future challenge demonstrates extremely low specific on state resistance and high breakdown voltage. Metal insulator semiconductor gate GaN transistor is also a technical challenge for faster switching, since it would give greater freedom of gate driving as a result of both high threshold voltage and widened gate voltage swing. Normally off operation free from hysteresis in the current voltage characteristics is confirmed in a recessed gate AlGaN/GaN heterojunction field effect transistor using AlON as a gate insulator. Fast switching characteristics are experimentally confirmed for both of the newly developed GaN devices, indicating their great potential for practical use.", "author_names": [ "Tetsuzo Ueda" ], "corpus_id": 191157177, "doc_id": "191157177", "n_citations": 18, "n_key_citations": 1, "score": 0, "title": "GaN power devices: current status and future challenges", "venue": "Japanese Journal of Applied Physics", "year": 2019 }, { "abstract": "Silicon technology, which is the most mainstream semiconductor technology, poses serious limitations on fulfilling the market demands in high frequency and high power applications. In response to these limitations, wide bandgap III nitride devices, including AlxGa1 xN/GaN heterojunction field effect transistors (HFETs) were introduced at about two decades ago to satisfy these rapidly growing market demands for high power/high frequency amplifiers and high voltage/high temperature switches. The most appealing features of III nitride technologies, and particularly AlxGa1 xN/GaN HFETs, in these applications, are the polarization induced high sheet carrier concentration, high breakdown voltage, high electron saturation velocity, and high maximum operating temperature. Therefore, the development of enhancement mode AlGaN/GaN HFETs is one of the most important endeavours in the past two decades. Low frequency noise (LFN) spectroscopy, empowered by a proper physics based model, is received as a capable tool for reliability studies. As a result, devising a physics based LFN model for AlGaN/GaN HFETs can be capable of not only evaluating the alternative techniques proposed for realization of enhancement mode AlGaN/GaN HFETs, but also more importantly forecasting the reliability, and noise performance of these devices. In this dissertation, for the first time, a physics based model for the low frequency drain noise current of AlGaN/GaN HFETs is proposed. The proposed model, through including the thermally activated and quantum tunneling processes of trapping/de trapping of electrons of channel into and out of the trap sites located both in the barrier and buffer layer of these HFETs, provides a descriptive picture for the LFN behavior of these devices. This work also aims to experimentally investigate the low frequency noise current characteristics of both conventional and newly proposed devices (i.e. fin and island isolated AlGaN/GaN HFETs) at various temperatures (i.e. 150, 300, and 450 K) and bias points in order to address the possible difficulties in performance of these devices. Matching of the trends proposed by the physics based model to the experimentally recorded LFN spectra of AlGaN/GaN HFETs designed according to a newly proposed technological variant for positive shifting the threshold voltage, confirms the accuracy and predicting power of the proposed model. The insights gained from this model on the latter group of devices provide evidence for the challenges of the aforementioned technological variants, and as a result offer assistance in proposing remedies for those challenges. In formulating the LFN model, a massive discrepancy between the predictions of the existing analytical relationships used by others in evaluating the subband energy levels of AlGaN/GaN HFETs and the realities of the polarization induced electron concentration of these HFETs was spotted. Careful evaluation of the polarization properties of these heterostructures unmasked the inaccuracy of the assumption of zero penetration of the electron wave into both the AlGaN barrier layer and the GaN buffer layer as the culprit in this discrepancy. In response to this observation, a model based on the variational method for calculating the first and second subband energy levels of AlGaN/GaN HFETs is developed. On the basis of this model, more accurate analytical frameworks for calculating these subband energy levels in AlGaN/GaN HFETs for a variety of barrier thicknesses and Al mole fractions in the barrier layer are proposed.", "author_names": [ "Farzin Manouchehri" ], "corpus_id": 108136385, "doc_id": "108136385", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Reliability Driven Experimental and Theoretical Study of Low Frequency Noise Characteristics of AlGaN/GaN HFETs", "venue": "", "year": 2014 }, { "abstract": "High voltage HFET's fabricated from nitride semiconductors utilizing the AlGaN/GaN heterojunction demonstrate excellent RF performance with RF output power greater than an order of magnitude higher than available from GaAs and InP based devices. However, the nitride devices demonstrate a reliability problem where the dc current and RF output power continually decrease as a function of time. The reliability problem is related to the conduction characteristics of the gate electrode and an electron tunneling mechanism where electrons leak from the gate to the surface of the semiconductor. In this work the physics responsible for this behavior are investigated and described", "author_names": [ "Robert Trew", "Yu Liu", "W Kuang", "Griff L Bilbro" ], "corpus_id": 17660484, "doc_id": "17660484", "n_citations": 16, "n_key_citations": 2, "score": 0, "title": "The Physics of Reliability for High Voltage AlGaN/GaN HFET's", "venue": "2006 IEEE Compound Semiconductor Integrated Circuit Symposium", "year": 2006 }, { "abstract": "In semiconductor devices manufacturing, various materials with different physico chemical characteristics are connected and over hundreds of sequenced processing steps are necessary. In this regard, thermomechanical stress due to compressive and tensile strain is a serious aspect inside the device. Residual thermomechanical stress due to large difference in coefficients of thermal expansion between the materials generates reliability problems not only at the bonded interfaces but also for the lifetime of the active regions of the high power semiconductors. In this study, blue LEDs based on gallium nitride (GaN) bonded to a silicon carrier by a gold layer were soldered with eutectic gold tin (AuSn) on a copper board or an aluminum insulated metal (AI IMS) For both boards a reflow process in presence of formic acid vapor was used for soldering. The assemblies were studied using Raman spectroscopy. A finite element model was developed to simulate the thermomechanical stress present in the assemblies. Measured and simulated values were compared and evaluated at room temperature, at 50degC and at 180degC. The results suggest guidelines for the optimization of the assembling process of LED based microelectronic devices.", "author_names": [ "E Liu", "Fosca Conti", "Raffaella Signorini", "Enrico Brugnolotto", "Sri Krishna Bhogaraju", "Gordon Elger" ], "corpus_id": 171096269, "doc_id": "171096269", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Modelling Thermo Mechanical Stress in GaN LEDs Soldered on Copper Substrate with Simulations Validated by Raman Experiments", "venue": "2019 20th International Conference on Thermal, Mechanical and Multi Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE)", "year": 2019 }, { "abstract": "High voltage HFET's fabricated from nitride semiconductors utilizing the AlGaN/GaN heterojunction or GaAs using field plates demonstrate excellent RF output power performance. The nitride HFET's produce RF output power greater than an order of magnitude higher than available from GaAs and InP based devices, and GaAs FET's fabricated with field plates can produce RF output power about a factor of two greater than standard FET's. However, the FET's demonstrate a reliability problem where the dc current and RF output power continually decrease as a function of time. The problem is more serious in the nitride HFET's, although both nitride based and GaAs based devices suffer reliability problems. The reliability problem is related to the conduction characteristics of the gate electrode and an electron tunneling mechanism where electrons leak from the gate to the surface of the semiconductor. In this work the physics responsible for this behavior are investigated and described. Physics based models suitable for use in RF circuit harmonic balance simulators have been developed, with excellent agreement between measured and simulated data. Design techniques to reduce the reliability problem will be discussed.", "author_names": [ "Robert Trew", "Ying Liu", "W Kuang", "Griff L Bilbro" ], "corpus_id": 109074412, "doc_id": "109074412", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Reliability modeling of high voltage AlGaN/GaN and GaAs field effect transistors", "venue": "SPIE OPTO", "year": 2008 }, { "abstract": "In recent years, a new kind of semiconductor detector called SiPM has been developed to detect a single optical photon as an alternative to PMT APD. SiPM have many advantages in terms of very fast timing response, high gain at low bias voltage, low power consumption, good temperature to voltage stability, insensitive to magnetic fields. Reliability, ruggedness, compactness, no excess light damages and long life span are our favorable characteristics. This device SiPM is a promising to find wide spread uses in nuclear medical imaging application, Environmental chemical, high energy physics and many other fields. Silicon photomultipliers are Silicon single photon sensitive devices built from an avalanche photodiode (APD) array on common Si substrate. The idea behind this device is the detection of single photon events in sequentially connected Si APDs. The dimension of each single APD can vary from 20 to 100 micrometers, and their density can be up to 103 mm2 Every APD in SiPM operates in Geiger mode and is coupled with the others by a polysilicon quenching resistor. Although the device works in digital/switching mode, the SiPM is an analog device because all the microcells are read in parallel making it possible to generate signals within a dynamic range from a single photon to 1000 photons for just a single square millimeter area device. The supply voltage (Vb) depends on APD technology used, and typically varies between 25 V and 70 V, thus being from 30 to 50 times lower than the voltage required for a traditional photomultiplier tubes (PMTs) operation. SiPM has been invented in Russia in Moscow Engineering Physics Institute [1] This design idea was then used with some variations by SensL, Photonique, Hamamatsu, KETEK, Voxtel Inc.", "author_names": [ "Chauhan Paresh", "Yashwant B Acharya" ], "corpus_id": 125201792, "doc_id": "125201792", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Comprehensive Study, Characterization Simulation of Silicon Photo Multiplier: A New Device for Low Light Detection", "venue": "", "year": 2013 }, { "abstract": "High voltage HFETpsilas fabricated from the AlGaN/GaN heterojunction demonstrate excellent RF output power performance. The nitride HFETpsilas produce RF output power greater than an order of magnitude higher than available from GaAs and InP based devices. However, the HFETs demonstrate a reliability problem where the dc current and RF output power continually decrease as a function of time. The reliability problem is shown to be related to the conduction characteristics of the gate electrode and an electron tunneling mechanism where electrons leak from the gate to the surface of the semiconductor. In this work the physics responsible for this behavior are investigated and described. Physics based models suitable for use in RF circuit harmonic balance simulators have been developed, with excellent agreement between measured and simulated data.", "author_names": [ "J Trew", "W Kuang", "Yu Liu", "Griff L Bilbro" ], "corpus_id": 24399381, "doc_id": "24399381", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Time dependent RF performance degradation modeling of AlGaN/GaN HFETs", "venue": "MIKON 2008 17th International Conference on Microwaves, Radar and Wireless Communications", "year": 2008 } ]

[ { "abstract": "Abstract Organic dyes generating from many industries are considered as a potential source of water pollution and have negative effects on human health. The present study was aimed to construct a green synthesis method for fabrication of ZnS based dual nano semiconductors and to compare the photocatalytic properties for removing cationic and anionic dyes. ZnS nanoparticles were synthesized using a template synthesis in bovine serum albumin (BSA) solution and then ZnS/PbS, ZnS/CdS and ZnS/Ag2S dual nano semiconductors were prepared using ion exchange method. Prepared nano semiconductors were characterized by using HR TEM, XRD, FTIR, TG/DTA and AAS. Moreover, photocatalytic activity of prepared nano semiconductors was tested against Rhodamine B (cationic dye) and Methyl Orange (anionic dye) Results revealed that a controllable ZnS/PbS, ZnS/CdS and ZnS/Ag2S ratio in nano semiconductors can be achieved by adjusting the ion exchange time. Prepared ZnS based composites exhibited higher photocatalytic efficiency than that of ZnS alone. In addition, photocatalytic activity of ZnS based dual nano semiconductors was found to be dependent upon composition and ratio of sulphides in nano semiconductors with environmental pH. It was concluded that the combination of template synthesis and ion exchange method is a feasible approach to fabricate new photocatalysts with higher photocatalytic activity.", "author_names": [ "Hua-jie Wang", "Ying Cao", "Le Wu", "Sha-Sha Wu", "Ali Raza", "Nan Liu", "Jin-Ye Wang", "Teruo Miyazawa" ], "corpus_id": 105473685, "doc_id": "105473685", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "ZnS based dual nano semiconductors (ZnS/PbS, ZnS/CdS or ZnS/Ag2S, A green synthesis route and photocatalytic comparison for removing organic dyes", "venue": "", "year": 2018 }, { "abstract": "Abstract Silver spongelike networks were synthesized from an alkaline pH solution of silver nitrate and glucose under solvothermal conditions. The products were characterized by X ray powder diffraction, UV visible spectroscopy, transmission electron microscopy, scanning electron microscopy and selected area electron diffraction. These Ag nanoparticles (NPs) appear to undergo sequentially linear aggregation and welding initially, and then, they randomly cross link into self supporting, three dimensional (3D) networks with time. The carboxylate groups, generated by glucose oxidation, interacted with the Ag nanostructures, resulting in formation of silver spongelike networks having very uniform wire diameters distributions (about 20 nm in diameter) A new plasmon band was observed in the longer wavelengths region (565 912 nm) of the conventional transverse plasmon resonance band at 430 nm. In principle, this one step, template free approach can also be extended to large scale 3D organizations of other transition/noble metal NPs.", "author_names": [ "Zao Yi", "Xibin Xu", "Kuibao Zhang", "Xiulan Tan", "Xibo Li", "Jiang-shan Luo", "Xin Ye", "Weidong Wu", "Jie Wu", "Yougen Yi", "Yongjian Tang" ], "corpus_id": 97983076, "doc_id": "97983076", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Green, one step and template free synthesis of silver spongelike networks via a solvothermal method", "venue": "", "year": 2013 }, { "abstract": "Abstract An efficient protocol for synthesis of nanosize zinc oxide without calcinations was developed by sonochemical method. The method involved only use of zinc acetate as a precursor and 1, 3 Propane diol as a solvent with multiple roles. In our study, 1,3 propanediol served multiple roles as promoter, base, stabiliser and template for synthesis of nanosize zinc oxide and it also eliminated use of any extraneous species. As prepared nanosize zinc oxide was well characterised with the help of TEM, XRD and EDAX. The analysis result showed that zinc oxide is found to be at nano scale, with uniform morphology and well crystalline nature. This is one of the facile and environmental benign protocol for synthesis of nanosize zinc oxide.", "author_names": [ "Kushal D Bhatte", "Dinesh N Sawant", "Dipak V Pinjari", "Aniruddha Bhalchandra Pandit", "Bhalchandra M Bhanage" ], "corpus_id": 97713516, "doc_id": "97713516", "n_citations": 32, "n_key_citations": 0, "score": 1, "title": "One pot green synthesis of nano sized zinc oxide by sonochemical method", "venue": "", "year": 2012 }, { "abstract": "Two major goals of hierarchically porous metal organic frameworks (HP MOFs) research are the reduction of energy consumption and the enhancement of production rate. Here, we develop a simple and versatile method for the rapid synthesis of three HP MOFs (Cu BTC, Cu BDC, and ZIF 8) through introducing zinc oxide (ZnO) and template simultaneously. The synthesis condition was facile, and the synthesis time could be shortened to 30 min. Moreover, the porosity and morphology of HP MOFs could be adjustable with variable amounts and types of template. A synergistic effect of the hydroxy double salt (HDS) and template is crucial for the synthesis, whereas no meso and macropores were formed in the individual employing of either the HDS or the template. The rapid synthesis mechanism was further elucidated by the mesoscopic dynamics simulation. Furthermore, the synthetic approach of HP MOFs was readily scalable with a space time yield (STY) of up to 1322 kg*m 3*d 1, which allowed the large scale production. The prep.", "author_names": [ "Feier Li", "Chongxiong Duan", "Hang Zhang", "Xin Yan", "Jinqing Li", "Hongxia Xi" ], "corpus_id": 103495367, "doc_id": "103495367", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Hierarchically Porous Metal Organic Frameworks: Green Synthesis and High Space Time Yield", "venue": "", "year": 2018 }, { "abstract": "The present work reveals a new and simple one pot green method to load doxorubicin (DOX) drugs in silica nanoparticles for efficient in vivo cancer therapy. The synthesis of DOX loaded silica nanoparticles (SiNPs/DOX) is based on the efficient encapsulation of DOX in surfactant Tween 80 micelles which act as a template for the formation of silica nanoparticles. The release profile, cellular uptake behavior, cytotoxicity and antitumor effect of SiNPs/DOX nanoparticles were investigated and compared to free DOX. The silica nanoparticles improved the cellular drug delivery efficiency and exhibited high cytotoxicity, successfully achieving the inhibition of tumor growth. Notably, the tumor size and weight of SiNPs/DOX group was 2 fold and 1.7 fold smaller than that of free DOX group, and 4 fold and 2 fold smaller than that of PBS group. The one pot green synthesis system may have the potential to be developed as a promising drug delivery system.", "author_names": [ "Shan Jiang", "L Hua", "Zilong Guo", "Lin Sun" ], "corpus_id": 46925229, "doc_id": "46925229", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "One pot green synthesis of doxorubicin loaded silica nanoparticles for in vivo cancer therapy.", "venue": "Materials science engineering. C, Materials for biological applications", "year": 2018 }, { "abstract": "Abstract The non ionic surfactant, Tween 80 (T80) a material with promising applications in the pharmaceutical, cosmetic, and food industries, has been explored here for the design of novel nanostructures (NS) We report here a direct one pot seedless green method for the synthesis of gold silver (AuAg) hollow cubic NS, with gold (90% being the major component. The concentration of T80 plays an important role in determining the shape of the NS. A minimum T80 concentration of 50 mM is required for the formation of hollow cubic NS, whose sizes are controlled by increasing the T80 concentration. The unique molecular structure of T80 directs its molecules to assemble into core shell cylindrical micelles that act as a soft template for the growth of the NS. Study of the mechanism for the formation of the NS suggests nucleation followed by co reduction of metal ions and its growth into hollow cubic NS over T80 micelles. The AuAg hollow cubic NS shows greater potential as efficient nanocatalysts than the non cubic NS obtained at lower T80 concentrations. The hollowness and the cubic shape of the NS contribute towards their effective surface area that facilitates efficient catalytic activity. The AuAg NS may have biological applications due to their cell viabilities.", "author_names": [ "Dickson Joseph", "Hoomin Lee", "Yun Suk Huh", "Young-Kyu Han" ], "corpus_id": 105744736, "doc_id": "105744736", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Cylindrical core shell tween 80 micelle templated green synthesis of gold silver hollow cubic nanostructures as efficient nanocatalysts", "venue": "", "year": 2018 }, { "abstract": "Mesoporous SiC ceramics were prepared using different natural biopolymers (guar, tragacanth, Arabic, and xanthan gum) as both template and carbon sources. Natural biopolymers are safe, biocompatible, and inexpensive materials that can be green candidates for carbon sources. Low temperature magnesiothermic technique was used to form porous silicon carbide. In this study, tetraethylorthosilicate was prepared by sol gel method and used as silica precursor. The mixture of silica and carbon sources was carbonized under argon atmosphere at 750 degC, and then, the reaction continued by adding magnesium powder at 700 degC. Products were characterized using SEM, BET/BJH, XRD, FTIR, and Raman spectroscopy. The produced SiC materials showed mesoporous structures with high surface area and identical structures related to their carbon precursors. The results suggest that the natural gums can be potentially used as carbon templates in controlled formation of nanostructures. Also the synthesized silicon carbide nanostructures were used as catalyst supports in oxidative desulfurization of a model fuel. For this purpose, MoO3 was immobilized on the surface of SiC supports by using peroxo molybdenum complex. Such excellent catalytic performance was attributed in the presence of silicon carbide (99, 98, 94, and 93% conversion for SiCs produced from Arabic, xanthan, guar, and tragacanth, respectively).Graphical Abstract", "author_names": [ "E Khomand", "Maryam Afsharpour" ], "corpus_id": 103582310, "doc_id": "103582310", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Green synthesis of nanostructured SiCs by using natural biopolymers (guar, tragacanth, Arabic, and xanthan gums) for oxidative desulfurization of model fuel", "venue": "International Journal of Environmental Science and Technology", "year": 2018 }, { "abstract": "Fabricating nanostructures (NS) with well developed morphologies and high surface areas is vital to the success of any designed material for its application in adsorption and catalysis. In this study, we prepared ZnIn2S4 NS with different morphologies using a soft template based precipitation method. X ray diffraction data show that the NS are crystalline with a hexagonal structure. Field emission scanning electron microscopy suggests that the NS are formed with different morphologies, such as lamellar structures, nanobeads, and nanopetal/nanoflake hybrids. Moreover, transmission electron microscopy confirmed the lamellar structure, which was composed of vertically grown 2D nanosheets. Brunauer Emmett Teller analysis indicates the specific surface area (135.36 to 197.63 m2 g 1) and pore width (1.41 to 4.54 nm) values of the NS vary with varying soft templates. The obtained NS have efficient adsorption performance towards malachite green dye and dichromate (Cr2O72 with maximum adsorption capacities of 1525 and 313 mg g 1, respectively, which are considerably higher than those of many other previously reported nanoadsorbents. The adsorption process follows the Freundlich isotherm model for the lamellar structure and the Langmuir isotherm model for the other morphologies. All adsorbents conformed to a pseudo second order rate kinetics model, and the best adsorbent could be recycled up to five times without significant loss of efficiency.", "author_names": [ "Afaq Ahmad Khan", "Arif Chowdhury", "Sunita Kumari", "Sahid Hussain" ], "corpus_id": 213072301, "doc_id": "213072301", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "The facile soft template morphology controlled (STMC) synthesis of ZnIn2S4 nanostructures and their excellent morphology dependent adsorption properties", "venue": "", "year": 2020 }, { "abstract": "In this research, a new nanomagnetic molecularly imprinted polymer (nanoMMIP) of brilliant blue FCF (BB) with high efficiency and nanomagnetic non imprinted polymer (nanoMNIP) were synthesized by a simple method in water medium as a green solvent. Acryl amide and N,N' methylene bis acrylamide were used as the functional monomer andcross linking agent, respectively. The synthesized nanoMMIP and nano MNIP were characterized using thermal gravimetric analysis (TGA) transmissionelectron microscopy (TEM) scanning electron microscopy(SEM) and Fouriertransforminfrared spectroscopy (FT IR) The nano MMIP,as a selective sorbent,was used to extract BB from real samples. The effect of pH, time and BB concentrationin addition toadsorption isothermswere studied. The imprinting induced extraction was confirmed by determination of recovery values for nano MNIP (37% and nano MMIP (90% The maximum binding capacity of nano MMIP for this template was 3.25 mg/g.", "author_names": [ "Naghmeh Arabzadeh", "Reza Akbarzadeh", "Ali Akbar Mohammadi", "Maher Darwish" ], "corpus_id": 104440640, "doc_id": "104440640", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Green synthesis and application of nanomagnetic molecularly imprinted polymerfor fast solid phase extraction of brilliant blue FCF from real samples", "venue": "Journal of Polymer Research", "year": 2018 }, { "abstract": "Abstract A green and facile strategy for the synthesis of copper nanoclusters (CuNCs) is developed using Na2S2O3 as a reducing agent and bovine serum albumin as a template. The CuNCs are characterized by ultraviolet visible, fluorescence and infrared spectroscopy, transmission electron microscopy and X ray photoelectron spectroscopy. When excited at 336 nm, a strong characteristic peak of fluorescence emission is found at 407 nm. Transmission electron microscopy shows that the obtained CuNCs exhibit a spherical shape with an average diameter of ~2 nm. In addition, the CuNCs exhibit excellent water solubility and stability. Subsequently, a fluorescence method for determining minocycline (MC) is established based on the effective fluorescence quenching of CuNCs by MC attributed to the inner filter effect. The linear range is from 1.00 to 100 mM with a detection limit of 0.76 mM. Selectivity and anti interference studies indicate that the nanoprobe presents good selectivity over other substances, including biomolecules and inorganic ions. The method is successfully used for MC detection in urine and plasma samples. Therefore, the proposed fluorescence strategy based on CuNCs can provide a convenient platform for the detection of MC in biomedical applications.", "author_names": [ "Baoying Kong", "Yanjie Cao", "Yongli Yu", "Shuang Zhao" ], "corpus_id": 224954282, "doc_id": "224954282", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Synthesis of sodium thiosulfate reduced copper nanoclusters using bovine serum albumin as a template and their applications in the fluorometric detection of minocycline", "venue": "", "year": 2020 } ]

[ { "abstract": "The art and science of the fabrication of thin solid films have an accelerated growth because of its impact in the electronic devices. The development of number of thin film devices in which, semiconductor thin films are mainly used, has revolutionized various fields. The investigations of different parameters governing the properties of semiconductor thin films lead to manipulation of these properties for the progress of humankind. The development of thin film technology has led to its application in diverse fields from microelectronics to optics, space science to aircrafts, and superconductivity to photovoltaic and to spintronics. Thus, the thin film studies have directly or indirectly caused the advancement of many new areas of research in solid state physics and chemistry and will continue to play increasingly important roles in the study of a variety of problems of basic and technological importance.", "author_names": [], "corpus_id": 174775928, "doc_id": "174775928", "n_citations": 0, "n_key_citations": 0, "score": 2, "title": "Chapter 2 Thin Film Preparation Methods for Deposition of SnSe Films 2 1", "venue": "", "year": 2012 }, { "abstract": "Thin film nanocomposite (TFN) membranes prepared by embedding nanofillers into an ultrathin polyamide layer have paved the way toward developing high performance reverse osmosis (RO) desalination membranes. Scale up production of TFN membranes is still a challenging issue, however, since previous studies have merely followed the same fabrication method for conventional RO membranes. Herein, we introduced a novel preparation method for TFN membranes using spray assisted nanofiller predeposition to circumvent the limitations in conventional methods. The precise control of nanofiller (ZIF 8) loading was possible by simply varying the spraying ZIF 8 concentration. Most importantly, TFN membranes prepared by both spray and conventional method showed similar RO performance, while the spray method only requires ~100 times the minimal amount of ZIF 8 with the most unprecedentedly short deposition time <1 min) ever reported. Our results revealed that the spray method would be promising for the scale up production.", "author_names": [ "Tae Hoon Lee", "In-Sung Park", "Jee Yeon Oh", "Jun Kyu Jang", "Ho Bum Park" ], "corpus_id": 104408135, "doc_id": "104408135", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Facile Preparation of Polyamide Thin Film Nanocomposite Membranes Using Spray Assisted Nanofiller Predeposition", "venue": "Industrial Engineering Chemistry Research", "year": 2019 }, { "abstract": "Abstract The present work reports the successful synthesis of the nanostructured carbon doped TiO2 thin films on glass substrate by combination of chemical vapor deposition (CVD) and ultrasonic methods, for the first time. In this method the ultrasound waves act as nebulizer for converting of sonochemically prepared TiO2 sol to the mist particles. These mist particles were thermally decomposed in subsequent CVD chamber at 320 degC to produce the carbon doped TiO2 thin films. The obtained thin films were characterized by means of X ray Diffraction (XRD) Raman spectroscopy, diffuse reflectance spectroscopy (DRS) X ray photoelectron spectroscopy (XPS) atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. The results show that the prepared thin films have anatase crystal structure and nanorod morphology, which calcination of them at 800 degC results in the conversion of nanorods to nanoparticles. In addition, the prepared samples have high transparency, monodispersity and homogeneity. The presence of the carbon element in the structure of the thin films causes the narrowing of the band gap energy of TiO2 to about 2.8 eV, which results in the improvement of visible light absorption capabilities of the thin film.", "author_names": [ "Hossein Rasoulnezhad", "Ghassem Kavei", "Kamran Ahmadi", "Mohammad Reza Rahimipour" ], "corpus_id": 100355584, "doc_id": "100355584", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Combined sonochemical/CVD method for preparation of nanostructured carbon doped TiO2 thin film", "venue": "", "year": 2017 }, { "abstract": "In this paper, we describe a binder free reduced graphene oxide/carbon nanotube hybrid thin film electrode prepared using a one step electrostatic spray deposition method. Though we introduce a novel method, we suspect that the greater potential impact is more related to the fact that this technique is able to accomplish producing an electrode with a single process and allows a degree of control over the film properties not yet found in other fabrication methods that require multiple steps (that include post processing) In order to investigate the effect of carbon nanotube as a nano spacer on the electrochemical properties of the reduced graphene oxide/carbon nanotube hybrid thin film electrodes, the various content of carbon nanotube was incorporated between the 2 dimensional layered reduced graphene oxide sheets to prevent restacking among reduced graphene oxide sheets and their electrochemical properties were systemically investigated using cyclic voltammetry, galvanostatic charge/discharge test and electrochemical impedance spectroscopy. The hybrid thin film electrode delivered a higher reversible specific capacitance of 187 F*g 1 at 0.5 A*g 1 and showed a better rate capability by maintaining 73% of the specific capacitance at 16 A*g 1 (vs. 0.5 A*g 1) which exhibit remarkable electrochemical performances than a RGO thin film electrodes for supercapacitor applications.", "author_names": [ "Hee-Chang Youn", "Seong-Min Bak", "Sang-Hoon Park", "Seung-Beom Yoon", "Kwang Chul Roh", "Kwang-Bum Kim" ], "corpus_id": 137125272, "doc_id": "137125272", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "One step preparation of reduced graphene oxide/carbon nanotube hybrid thin film by electrostatic spray deposition for supercapacitor applications", "venue": "Metals and Materials International", "year": 2014 }, { "abstract": "Abstract A novel series of alkyl monosubstituted thiophene/phenylene co oligomers (TPCOs) has been synthesized and characterized. The introduction of alkyl chains to TPCOs improved the solubility in organic solvents. Thin films of these compounds were prepared by the vacuum deposition, solution cast, and skim methods. Of these, the solution cast films and skim films consist of highly ordered structures characterized by molecular bilayers. In particular, the skim method produced a large sized free standing thin film. We investigated the carrier transport of the thin films on the field effect transistor (FET) configurations. These FET devices exhibited typical p channel characteristics with clear saturation region. The introduction of alkyl monosubstituents is responsible for enhancement in the carrier mobility. The device characteristics are contrasted with those of alkyl disubstituted compounds.", "author_names": [ "Ryuji Hirase", "Mari Ishihara", "Toshifumi Katagiri", "Yosuke Tanaka", "Hisao Yanagi", "Shu Hotta" ], "corpus_id": 93572003, "doc_id": "93572003", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Alkyl monosubstituted thiophene/phenylene co oligomers: Synthesis, thin film preparation, and transistor device characteristics", "venue": "", "year": 2014 }, { "abstract": "Abstract Numerous LiCoO2 cathode thin films have been prepared for all solid state thin film battery applications. Preparation methods include sputtering, pulsed laser deposition, electron beam evaporation, screen printing, and spin coating. When compared to vacuum deposition methods, the solution processed fabrication methods could result in significant cost savings and large area production. Unfortunately, high temperature annealing (Tanneal 700 degC) of LiCoO2 cathode thin film is usually crucial for achieving a high performance layered phase. Here, we report on phase control of spin coated LiCoO2 thin film by varying the molecular weight of polyvinylpyrrolidone (PVP) at low temperature. We could achieve thick and smooth film morphology by optimizing the PVP molecular weight. This method could be a promising cathode layer for low cost thin film batteries.", "author_names": [ "Seung Min Yu", "Chahwan Hwang", "Do Jeon Kim", "Joohyung Park", "Seonhyoung Kim", "Jongin Hong", "Jihyun An", "Tae Hoon Lee", "Myung-Gil Kim" ], "corpus_id": 139362373, "doc_id": "139362373", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Characterization of low temperature solution processed LiCoO2 thin film cathode with molecular weight control of polyvinylpyrrolidone", "venue": "", "year": 2018 }, { "abstract": "The CISSY end station combines thin film deposition (sputtering, molecular beam epitaxy ambient pressure methods) with surface and bulk sensitive analysis (photo emission, x ray emission, x ray absorption) in the same UHV system, allowing fast and contamination free transfer between deposition and analysis. It is mainly used for the fabrication and characterization of thin film devices and their components like thin film photovoltaic cells, water splitting devices and other functional thin film materials.", "author_names": [ "Iver Lauermann", "Alexander Steigert" ], "corpus_id": 64056897, "doc_id": "64056897", "n_citations": 19, "n_key_citations": 2, "score": 0, "title": "CISSY: A station for preparation and surface/interface analysis of thin film materials and devices", "venue": "", "year": 2016 }, { "abstract": "Pollution of water resources with pesticide compounds has raised serious environmental problems, and for photocatalytic degradation of these pollutants, thin film photocatalysts are preferred to colloidal ones due to the separation problem of colloidal nanoparticles. In this work, nanostructured TiO2 and N doped TiO2 thin films with high transparency were deposited on glass and quartz substrates through sonochemical chemical vapor deposition (CVD) method. The films prepared on glass and quartz substrates had nanocubic and nanospherical morphology, respectively. The presence of N atoms in the structure of TiO2 resulted in a decrease in the band gap energy of TiO2 and also in the reduction of photogenerated electron hole recombination rate. Furthermore, the presence of N atoms induced the formation of Ti3+ species which can act as hole trapping centers. The prepared thin films were also used for the visible light photocatalytic degradation of paraoxon pesticide. According to these results among the prepared thin films, the N doped TiO2 thin films have higher photocatalytic activity than pure TiO2 thin films. Moreover, in comparison with the thin films deposited on quartz substrate, the films on glass substrate have higher photocatalytic performance, which can be related to the special nanocubic morphology of these samples.", "author_names": [ "Hossein Rasoulnezhad", "Ghader Hosseinzadeh", "Reza Hosseinzadeh", "Naser Ghasemian" ], "corpus_id": 105110695, "doc_id": "105110695", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Preparation of transparent nanostructured N doped TiO2 thin films by combination of sonochemical and CVD methods with visible light photocatalytic activity", "venue": "Journal of Advanced Ceramics", "year": 2018 }, { "abstract": "Abstract The structural properties of In2Se3 precursor thin films grown by chemical spray pyrolysis (CSP) and physical vapor deposition (PVD) methods were compared. This is to investigate the feasibility to substitute PVD process of CuInSe2 (CISe) films by CSP films as precursor layer, thus decreasing the production cost by increasing material utilization efficiency. Both films of 1 mm thickness were deposited at the same substrate temperature of 380 degC. X ray diffraction and Raman spectra confirm the formation of g In2Se3 crystalline phase for both films. The PVD and CSP films exhibited (110) and (006) preferred orientations, respectively. The PVD films showed a smaller full width at half maximum value (0.09deg) compared with CSP layers (0.1deg) Films with the same crystalline phase but with different orientations are normally used in the preparation of high quality CISe films by 3 stage process. Scanning electron microscope cross section images showed an important difference in grain size with well defined larger grains of size 1 2 mm in the PVD films as compared to CSP layers (600 nm) Another important characteristic that differentiates the two precursor films is the oxygen contamination. X ray photoelectron spectroscopy showed the presence of oxygen in CSP films. The oxygen atoms could be bonded to indium by replacing Se vacancies, which are formed during CSP deposition. Taking account of the obtained results, such CSP films can be used as precursor layer in a PVD process in order to produce CISe absorber films.", "author_names": [ "Pablo Itzam Reyes-Figueroa", "Thomas Painchaud", "Thomas Lepetit", "Sylvie Harel", "Ludovic Arzel", "Junsin Yi", "Nicolas Barreau", "Subramaniam Velumani" ], "corpus_id": 95812300, "doc_id": "95812300", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Structural properties of In2Se3 precursor layers deposited by spray pyrolysis and physical vapor deposition for CuInSe2 thin film solar cell applications", "venue": "", "year": 2015 }, { "abstract": "Abstract High temperature superconductor thin films of high quality have successfully been deposited on oxide substrates with good lattice match to the films by a variety of different techniques. Pulsed laser deposition [PLD] and sputtering have been appeared to be the most popular methods at least in the scope of thin film preparation for basic research and development. Both methods do not require any post deposition annealing steps if the conden sation of the film is done at high substrate temperatures [e.g. 750deg C] and high oxygen partial pressure [e.g. 10 200 Pa] Films deposited by both methods using optimized preparation conditions show comparable super conducting parameters like critical temperatures exceeding 90 K and critical currents larger than 10 6 A/cm 2 at 77K. The different growth mechanisms of the films prepared by the two methods give rise to some morphological differences of the films. The advantages of PLD vs sputtering are discussed and specified with respect to their potential in the research area as well as in the application oriented work. Some recent developments like large area in situ deposition by sputtering, epitaxial growth of YBCO films with oriented in plane c axis by PLD and epitaxial growth of YBCO films on epitaxial buffer layers on silicon are discussed.", "author_names": [ "H -U Habermeier", "Gunter Beddies", "Bernd Leibold", "G Lu", "Gunter P Wagner" ], "corpus_id": 120775577, "doc_id": "120775577", "n_citations": 38, "n_key_citations": 1, "score": 0, "title": "Y Ba Cu O high temperature superconductor thin film preparation by pulsed laser deposition and RF sputtering: A comparative study", "venue": "", "year": 1991 } ]

[ { "abstract": "Carbon \"quantum\" dots (or carbon dots) have emerged as a new class of optical nanomaterials. Beyond the widely reported bright fluorescence emissions in carbon dots, their excellent photoinduced redox properties that resemble those found in conventional semiconductor nanostructures are equally valuable, with photon electron conversion applications from photovoltaics to CO2 photocatalytic reduction. In this work we used gold doped carbon dots from controlled synthesis as water soluble catalysts for a closer examination of the visible light photoconversion of CO2 into small organic acids, including acetic acid (for which the reduction requires many more electrons than that for formic acid) and, more interestingly, for the significantly enhanced photoconversion with higher CO2 pressures over an aqueous solution of the photocatalysts. The results demonstrate the nanoscale semiconductor equivalent nature of carbon dots, with excellent potential in energy conversion applications.", "author_names": [ "Sushant Sahu", "Yamin Liu", "Ping Wang", "Christopher E Bunker", "Kurukulasuriya Alexius Shiral Fernando", "William K Lewis", "Elena A Guliants", "F Yang", "Jinping Wang", "Ya-Ping Sun" ], "corpus_id": 39603808, "doc_id": "39603808", "n_citations": 54, "n_key_citations": 0, "score": 1, "title": "Visible light photoconversion of carbon dioxide into organic acids in an aqueous solution of carbon dots.", "venue": "Langmuir the ACS journal of surfaces and colloids", "year": 2014 }, { "abstract": "Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy", "author_names": [ "Dimitrios Tasis", "Nikos Tagmatarchis", "Alberto Bianco", "Maurizio Prato" ], "corpus_id": 28994897, "doc_id": "28994897", "n_citations": 3393, "n_key_citations": 30, "score": 0, "title": "Chemistry of carbon nanotubes.", "venue": "Chemical reviews", "year": 2006 }, { "abstract": "THE synthesis of molecular carbon structures in the form of C60 and other fullerenes1 has stimulated intense interest in the structures accessible to graphitic carbon sheets. Here I report the preparation of a new type of finite carbon structure consisting of needle like tubes. Produced using an arc discharge evaporation method similar to that used for fullerene synthesis, the needles grow at the negative end of the electrode used for the arc discharge. Electron microscopy reveals that each needle comprises coaxial tubes of graphitic sheets, ranging in number from 2 up to about 50. On each tube the carbon atom hexagons are arranged in a helical fashion about the needle axis. The helical pitch varies from needle to needle and from tube to tube within a single needle. It appears that this helical structure may aid the growth process. The formation of these needles, ranging from a few to a few tens of nanometres in diameter, suggests that engineering of carbon structures should be possible on scales considerably greater than those relevant to the fullerenes.", "author_names": [ "Sumio Iijima" ], "corpus_id": 4302490, "doc_id": "4302490", "n_citations": 34948, "n_key_citations": 535, "score": 0, "title": "Helical microtubules of graphitic carbon", "venue": "Nature", "year": 1991 }, { "abstract": "The past several decades have seen a significant rise in atmospheric carbon dioxide levels resulting from the combustion of hydrocarbon fuels. A solar energy based technology to recycle carbon dioxide into readily transportable hydrocarbon fuel (i.e. a solar fuel) would help reduce atmospheric CO2 levels and partly fulfill energy demands within the present hydrocarbon based fuel infrastructure. We review the present status of carbon dioxide conversion techniques, with particular attention to a recently developed photocatalytic process to convert carbon dioxide and water vapor into hydrocarbon fuels using sunlight.", "author_names": [ "Somnath Chanda Roy", "Oomman K Varghese", "Maggie Paulose", "Craig A Grimes" ], "corpus_id": 29021379, "doc_id": "29021379", "n_citations": 1135, "n_key_citations": 7, "score": 0, "title": "Toward solar fuels: photocatalytic conversion of carbon dioxide to hydrocarbons.", "venue": "ACS nano", "year": 2010 }, { "abstract": "Increasing atmospheric CO(2) levels have generated much concern, driving the ongoing carbon sequestration effort. A compelling CO(2) sequestration option is its photocatalytic conversion to hydrocarbons, for which the use of solar irradiation represents an ultimate solution. Here we report a new strategy of using surface functionalized small carbon nanoparticles to harvest visible photons for subsequent charge separation on the particle surface in order to drive the efficient photocatalytic process. The aqueous solubility of the catalysts enables photoreduction under more desirable homogeneous reaction conditions. Beyond CO(2) conversion, the nanoscale carbon based photocatalysts are also useful for the photogeneration of H(2) from water under similar conditions.", "author_names": [ "Li Cao", "Sushant Sahu", "Parambath Anilkumar", "Christopher E Bunker", "Juan Xu", "Kurukulasuriya Alexius Shiral Fernando", "Ping Wang", "Elena A Guliants", "Kenneth N Tackett", "Ya-Ping Sun" ], "corpus_id": 5269889, "doc_id": "5269889", "n_citations": 457, "n_key_citations": 3, "score": 0, "title": "Carbon nanoparticles as visible light photocatalysts for efficient CO2 conversion and beyond.", "venue": "Journal of the American Chemical Society", "year": 2011 }, { "abstract": "The emergence of semiconductor nanocrystals as the building blocks of nanotechnology has opened up new ways to utilize them in next generation solar cells. This paper focuses on the recent developments in the utilization of semiconductor quantum dots for light energy conversion. Three major ways to utilize semiconductor dots in solar cell include (i) metal semiconductor or Schottky junction photovoltaic cell (ii) polymer semiconductor hybrid solar cell, and (iii) quantum dot sensitized solar cell. Modulation of band energies through size control offers new ways to control photoresponse and photoconversion efficiency of the solar cell. Various strategies to maximize photoinduced charge separation and electron transfer processes for improving the overall efficiency of light energy conversion are discussed. Capture and transport of charge carriers within the semiconductor nanocrystal network to achieve efficient charge separation at the electrode surface remains a major challenge. Directing the future resear.", "author_names": [ "Prashant V Kamat" ], "corpus_id": 98235548, "doc_id": "98235548", "n_citations": 2216, "n_key_citations": 18, "score": 0, "title": "Quantum Dot Solar Cells. Semiconductor Nanocrystals as Light Harvesters", "venue": "", "year": 2008 }, { "abstract": "Photocatalysts and Photoelectrodes James L. White, Maor F. Baruch, James E. Pander III, Yuan Hu, Ivy C. Fortmeyer, James Eujin Park, Tao Zhang, Kuo Liao, Jing Gu, Yong Yan, Travis W. Shaw, Esta Abelev, and Andrew B. Bocarsly* +Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States +Chemical and Materials Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States", "author_names": [ "James L White", "Maor F Baruch", "James E Pander Iii", "Yuan Hu", "Ivy C Fortmeyer", "James Eujin Park", "Tao Zhang", "Kuo Liao", "Jing Gu", "Yong Yan", "Travis W Shaw", "Esta Abelev", "Andrew B Bocarsly" ], "corpus_id": 206534215, "doc_id": "206534215", "n_citations": 878, "n_key_citations": 3, "score": 0, "title": "Light Driven Heterogeneous Reduction of Carbon Dioxide: Photocatalysts and Photoelectrodes.", "venue": "Chemical reviews", "year": 2015 }, { "abstract": "In recent years, the area of developing visible light active photocatalysts based on titanium dioxide has been enormously investigated due to its wide range of applications in energy and environment related fields. Various strategies have been designed to efficiently utilize the solar radiation and to enhance the efficiency of photocatalytic processes. Building on the fundamental strategies to improve the visible light activity of TiO2 based photocatalysts, this Perspective aims to give an insight into many contemporary developments in the field of visible light active photocatalysis. Various examples of advanced TiO2 composites have been discussed in relation to their visible light induced photoconversion efficiency, dynamics of electron hole separation, and decomposition of organic and inorganic pollutants, which suggest the critical need for further development of these types of materials for energy conversion and environmental remediation purposes.", "author_names": [ "Swagata \"Ban\" Banerjee", "Suresh C Pillai", "Polycarpos Falaras", "Kevin E O'Shea", "John Anthony Byrne", "Dionysios D Dionysiou" ], "corpus_id": 38775156, "doc_id": "38775156", "n_citations": 427, "n_key_citations": 9, "score": 0, "title": "New Insights into the Mechanism of Visible Light Photocatalysis.", "venue": "The journal of physical chemistry letters", "year": 2014 }, { "abstract": "ii DEDICATION iii ACKNOWLEDGMENTS iv LIST OF TABLES viii LIST OF FIGURES ix LIST OF SCHEMES. xviii", "author_names": [ "Sushant Sahu" ], "corpus_id": 136573386, "doc_id": "136573386", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "DEVELOPMENT AND EVALUATION OF CARBON BASED QUANTUM DOTS FOR CARBON DIOXIDE PHOTOCONVERSION", "venue": "", "year": 2014 }, { "abstract": "World is facing problems of global warming as well as energy crisis. Both these problems can be solved to a reasonable extent by photoreduction of carbon dioxide. Here, photocatalysis enters the scene. Photocatalytic reduction to synthetic organic fuels like formaldehyde, methanol, formic acid, acetic acid, methane, etc. will provide a solution to the problem of energy crisis as it will give us alternate fuels, which can be burnt into fuel cells to generate electricity. Once we get electricity at the cost of carbon dioxide, one can convert this form of energy to any other form of energy. Secondly, it will give a solution to put a check on the increasing amount of carbon dioxide, which is the main culprit of global warming. Any conventional fuel on burring will add some molecules of carbon dioxide in the atmosphere, but synthetic fuels derived by photocatalytic reduction of carbon dioxide will not add even a single molecule of carbon dioxide in the environment. It can be considered as a short term loan of carbon dioxide from the atmosphere as the carbon dioxide molecules utilized in the synthesis of alternate fuels are generated back on burning it in fuel cell.", "author_names": [ "Rakshit Ameta", "Shikha Panchal", "N K Ameta", "Suresh C Ameta" ], "corpus_id": 93634845, "doc_id": "93634845", "n_citations": 21, "n_key_citations": 2, "score": 0, "title": "Photocatalytic Reduction of Carbon Dioxide", "venue": "", "year": 2013 } ]

[ { "abstract": "Hoist scheduling in automated electroplating lines has been extensively studied in a static environment. However, practical electroplating lines are subject to diversified unforeseen disruptions that require frequent rescheduling to maintain or optimize system performance. This paper addresses a hoist scheduling problem, where randomly arriving jobs need to be inserted into an existing schedule without changing the sequence of hoist moves already scheduled. The objective is to minimize the total completion time of all the jobs in the existing schedule and a newly inserted job. We develop a polynomial time heuristic that adjusts the starting times of the existing hoist moves to a limited extent but does not bring about a severe disturbance of the existing hoist moves. We compare our algorithm with two existing approaches with different rescheduling policies (i.e. partial and zero adjustment of the existing schedule) We empirically analyze the productivity and the stability of the schedules generated by the three approaches. Computational results demonstrate that our algorithm can generate more productive and stable schedules than the two existing approaches. Note to Practitioners Electroplating and chemical surface treatment lines with automated material handling hoists are commonplace in electronics, semiconductor, and many other manufacturing industries. In an uncertain environment, hoist rescheduling plays an important role in improving the productivity and reducing the impact of disruptions. This paper presents a hoist scheduling algorithm to deal with dynamic job arrivals by considering the impact of the disturbance incurred by rescheduling. Our algorithm can generate a better schedule with smaller total completion time and slighter disturbance than the existing algorithms. The proposed algorithm runs in polynomial time and can be used to control hoist operations in practical electroplating lines. A comparative analysis provides useful insights on the implementation of rescheduling approaches and policies to industry practitioners.", "author_names": [ "Pengyu Yan", "Ada Che", "Eugene Levner", "Shi Qiang Liu" ], "corpus_id": 49556120, "doc_id": "49556120", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "A Heuristic for Inserting Randomly Arriving Jobs Into an Existing Hoist Schedule", "venue": "IEEE Transactions on Automation Science and Engineering", "year": 2018 }, { "abstract": "The cyclic hoist scheduling problem (CHSP) is a well studied optimisation problem due to its importance in industry. Despite the wide range of solving techniques applied to the CHSP and its variants, the models have remained complicated and inflexible, or have failed to scale up with larger problem instances. This article re examines modelling of the CHSP and proposes a new simple, flexible constraint programming formulation. We compare current state of the art solving technologies on this formulation, and show that modelling in a high level constraint language, MiniZinc, leads to both a simple, generic model and to computational results that outperform the state of the art. We further demonstrate that combining integer programming and lazy clause generation, using the multiple cores of modern processors, has potential to improve over either solving approach alone.", "author_names": [ "Mark Wallace", "N Yorke-Smith" ], "corpus_id": 228811818, "doc_id": "228811818", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "A new constraint programming model and solving for the cyclic hoist scheduling problem", "venue": "Constraints An Int. J.", "year": 2020 }, { "abstract": "The Hoist Scheduling Problem is combinatory, so tools such as mathematical programming need to be used to get the sequence of movements, respecting the constraints of the process by minimizing the cycle time. A sequence in which the order of movements follows the order of the process is known as the basic diagram. These schedules do not have any clearance for the hoist to make any other movements, resulting in a loss in productivity. This chapter takes the production line of a Mexican factory as a case study, analyzing the hoist's travelling speed to find sequences of movements that could improve productivity. The results of the study indicate that the cycle time has a nonlinear behavior in respect of the hoist's travelling speed and it was determined that there are travelling speeds for which sequences are obtained with enough clearance to make other movements and keep other carriers on the line. A suitable speed was estimated in the case. An Analysis of the Traveling Speed in the Traveling Hoist Scheduling Problem for Electroplating Processes", "author_names": [ "Jose Itzcoatl Gomar-Madriz", "Salvador Hernandez-Gonzalez", "J Navarrete-Damian" ], "corpus_id": 208092401, "doc_id": "208092401", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An Analysis of the Traveling Speed in the Traveling Hoist Scheduling Problem for Electroplating Processes", "venue": "", "year": 2020 }, { "abstract": "Electroplating facilities often face the Cyclic Hoist Scheduling Problem when a repetitive sequence of moves is searched for the hoists. This paper addresses this optimization problem extended to the design of the workshop, where we aim to minimize both the cycle time and the number of hoists used. For this goal, we propose a genetic meta heuristic approach which introduces a novel solution encoding to enlarge the solutions' search space. Our encoding procedure is based on hoists' empty moves, and includes separator characters. With the latter, we obtain solutions that were not reachable by previous approaches. Each solution obtained thanks to the genetic operators is evaluated by using a Mixed Integer Linear Program. This one checks the constraints of the problem (such as capacity constraints and soaking time bounds) and computes the smallest cycle time for a given moving sequence and its associated number of hoists. Some results are presented using benchmark instances for which our approach allows to improve the best known solutions.", "author_names": [ "Laajili Emna", "Lamrous Sid", "Manier Marie-Ange", "Nicod Jean-Marc" ], "corpus_id": 209900422, "doc_id": "209900422", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Genetic Algorithm Based Approach for the Multi Hoist Design and Scheduling Problem", "venue": "2019 International Conference on Industrial Engineering and Systems Management (IESM)", "year": 2019 }, { "abstract": "In this paper, we propose a Mixed Integer Linear Programming model for solving a hoist scheduling problem with several transportation resources. This model complements initial work that neglected the risk of collisions between hoists. This new model identifies and manages the various possible collision situations, and it is intended to be integrated as a solution evaluation module in a hybrid algorithm addressing the broader and more complex joint problem of sizing transport resources and scheduling surface treatment workshops. In this global approach, an evolutionary algorithm first generates partially feasible solutions, whose total feasibility is then verified a posteriori, thanks to the proposed new model. This model is validated through tests performed on instances of the literature.", "author_names": [ "Emna Laajili", "Sid Lamrous", "Marie-Ange Manier", "Jean Marc Nicod" ], "corpus_id": 208629912, "doc_id": "208629912", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Collision Free Based Model for the Cyclic Multi Hoist Scheduling Problem", "venue": "2019 IEEE International Conference on Systems, Man and Cybernetics (SMC)", "year": 2019 }, { "abstract": "The current paper deals with the cyclic multi hoist scheduling problem in electroplating lines considering rentrance. Identical parts are produced with processing time windows. Moreover, re entrance is also considered. These together make it more challenged to obtain better schedules improving the productivity. To achieve this, multi degree cycles are considered. To our best knowledge, this is the first research in this generally complicated scenario. In order to maximize the productivity of the production line, i.e. minimize the cycle time for a given degree, operations of hoists are first analyzed in detail to avoid their collision. Then, operations related the re entrance are modeled. Based on these work, a mixed integer linear programming model is proposed. An industrial instances is used to test the proposed model. It is solved using the commercial software ILOG CPLEX. Results illustrate the efficiency of the proposed approach.", "author_names": [ "Xin Li", "Yanchun Pan", "Richard Y K Fung" ], "corpus_id": 211026578, "doc_id": "211026578", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optimal Scheduling of the Reentrant Multi Degree Cyclic Multi Hoist Scheduing Problem", "venue": "2019 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM)", "year": 2019 }, { "abstract": "Abstract The pollution routing problem aims to route a number of vehicles and determines their speeds on each route segment to minimize total cost, including fuel, emission and driver costs. Recently, carbon pricing initiatives have been widely implemented worldwide. With consideration of the interactions between carbon pricing initiatives and freight schedules, this paper presents a carbon pricing initiatives based bi level pollution routing problem involving an authority and a freight company. An interactive solution approach integrating a fuzzy logic controlled particle swarm optimization and a modified adaptive large neighborhood search heuristic is designed to search for solutions for the carbon pricing initiatives based bi level pollution routing problem. Computational experiments and analysis are then conducted to shed light on the influence of carbon pricing initiatives on carbon emissions and the total cost of freight companies. In this part, extended models for the carbon pricing initiatives based bi level pollution routing problem with a freight company delivering to multiple regions and with multiple freight companies are proposed and computed using the algorithms based on the interactive solution approach. The results indicate that the proposed method can promote freight company improvements in emission performance, and assist authorities in making decisions for road freight transport carbon emission reduction.", "author_names": [ "Rui Qiu", "Jiuping Xu", "Ruimin Ke", "Ziqiang Zeng", "Yinhai Wang" ], "corpus_id": 216480140, "doc_id": "216480140", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Carbon pricing initiatives based bi level pollution routing problem", "venue": "Eur. J. Oper. Res.", "year": 2020 }, { "abstract": "Abstract The hybrid flowshop scheduling problem (HFSP) has been widely studied in the past decades. The most commonly used criterion is production efficiency. Green criteria, such as energy consumption and carbon emission, have attracted growing attention with the improvement of the environment protection awareness. Limited attention has been paid to noise pollution. However, noise pollution can lead to health and emotion disorder. Thus, this paper studies a multi objective HFSP considering noise pollution in addition to production efficiency and energy consumption. First, we formulate a new mixed integer programming model for this multi objective HFSP. To realize the green scheduling, one energy conservation/noise reduction strategy is embedded into this model. Then, a novel multi objective cellular grey wolf optimizer (MOCGWO) is proposed to address this problem. The proposed MOCGWO integrates the merits of cellular automata (CA) for diversification and variable neighborhood search (VNS) for intensification, which balances exploration and exploitation. Finally, to validate the efficiency and effectiveness of the proposed MOCGWO, we compare our proposal with other well known multi objective evolutionary algorithms by conducting comparison experiments. The experimental results show that the proposed MOCGWO is significantly better than its competitors on this problem.", "author_names": [ "Chao Lu", "Liang Gao", "Quanke Pan", "Xinyu Li", "Jun Zheng" ], "corpus_id": 59336425, "doc_id": "59336425", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "A multi objective cellular grey wolf optimizer for hybrid flowshop scheduling problem considering noise pollution", "venue": "Appl. Soft Comput.", "year": 2019 }, { "abstract": "Many optimization algorithms have been proposed to solve hybrid flowshop scheduling problem (HFSP) However, with the development of industry and society, labor right and labor safety have become important problem to consider in production scheduling. So the green HFSP considering makespan, noise and dust pollution becomes an urgent problem to be solved. In this paper, the rider optimization algorithm (ROA) is modified into the multi objective rider optimization algorithm (MOROA) using Pareto archive and neighborhood sorting techniques. The Pareto archive and neighborhood sorting technology make the Pareto optimal solution set of MOROA have higher coverage and more solutions. Then MOROA is discretized into discrete MOROA (DMOROA) to solve the HFSP considering makespan, noise and dust pollution. DMOROA is tested on 10, 30 and 50 jobs HFSP considering makespan, noise and dust pollution. The test results are compared with two multi objective algorithms to verify the performance of DMOROA. And the test results verify that the DMOROA is superior to the comparison algorithms in search accuracy, number of non dominated solutions, diversity of solution set and stability. Therefore, DMOROA is effective in solving multi objective HFSP considering makespan, noise and dust pollution.", "author_names": [ "Yanming Fu", "Zhuohang Li", "Ningjiang Chen", "Chiwen Qu" ], "corpus_id": 218832305, "doc_id": "218832305", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A Discrete Multi Objective Rider Optimization Algorithm for Hybrid Flowshop Scheduling Problem Considering Makespan, Noise and Dust Pollution", "venue": "IEEE Access", "year": 2020 }, { "abstract": "This paper deals with the robust optimization for the cyclic hoist scheduling problem with processing time window constraints. The robustness of a cyclic hoist schedule is defined as its ability to remain stable in the presence of perturbations or variations of certain degree in the hoist transportation times. With such a definition, we propose a method to measure the robustness of a cyclic hoist schedule. A bi objective mixed integer linear programming (MILP) model, which aims to optimize cycle time and robustness, is developed for the robust cyclic hoist scheduling problem. We prove that the optimal cycle time is a strictly increasing function of the robustness and the problem has infinite Pareto optimal solutions. Furthermore, we derive the so called ideal point and nadir point that define the lower and upper bounds for the objective values of Pareto front. A Pareto optimal solution can be obtained by solving a single objective MILP model to minimize the cycle time for a given value of robustness or maximize the robustness for a specific cycle time. The single objective MILP models are solved using commercial optimization software CPLEX. Computational results on several benchmark instances and randomly generated instances indicate that the proposed approach can solve large scale problems within a reasonable amount of time.", "author_names": [ "Ada Che", "Jianguang Feng", "Haoxun Chen", "Chengbin Chu" ], "corpus_id": 22472184, "doc_id": "22472184", "n_citations": 34, "n_key_citations": 2, "score": 0, "title": "Robust optimization for the cyclic hoist scheduling problem", "venue": "Eur. J. Oper. Res.", "year": 2015 } ]

[ { "abstract": "Two dimensional semiconductors have a number of valuable properties that could be used to create novel electronic devices. However, creating 2D devices with good contacts and stable performance has proved challenging. Here we show that transferred via contacts, made from metal embedded in insulating hexagonal boron nitride and dry transferred onto 2D semiconductors, can be used to create high quality 2D transistors. The approach prevents damage induced by direct metallization and allows full glovebox processing, providing a clean, stable and damage free platform for 2D device fabrication. Using the approach, we create field effect transistors (FETs) from bilayer p type tungsten diselenide (WSe2) that exhibit high hole mobility and low contact resistance. The fabricated devices also exhibit high current and stability for over two months of measurements. Furthermore, the low contact resistance and clean channel allow us to create a nearly ideal top gated p FET with a subthreshold swing of 64 mV per decade at 290 K.Bilayer WSe2 field effect transistors with near ideal device characteristics can be created using transferred via contacts made from metal embedded hexagonal boron nitride.", "author_names": [ "Younghun Jung", "Min Sup Choi", "Ankur Nipane", "Abhinandan Borah", "Bumho Kim", "Amirali Zangiabadi", "Takashi Taniguchi", "Kenji Watanabe", "Won Jong Yoo", "James C Hone", "James T Teherani" ], "corpus_id": 182892564, "doc_id": "182892564", "n_citations": 49, "n_key_citations": 0, "score": 1, "title": "Transferred via contacts as a platform for ideal two dimensional transistors", "venue": "Nature Electronics", "year": 2019 }, { "abstract": "The purpose of this study was to determine whether information of the homeopathic remedy \"Cerebrum Compositum\" transferred via a \"biophoton therapy device\" exerts an effect on isolated rat cortical neurons when tested versus untreated control. 60 x 103 neurons were used per group according to treatment in each of 4 experiments. Viability after 10 days was defined by a) synaptic size, b) the number of synaptic contacts and c) by longevity. Synaptic size in the test group was 63% greater (i.e. equal to 163% of) as compared to control W0 (100% (p<0.01) The number of synaptic contacts in the test group was 49% greater (i.e. equal to 149% of) than W0 (p<0.01) These trends could also be observed in the 4 sub experiments separately. There was no difference between the groups respecting longevity. Data are in line with previous findings on information transfer via the biophoton therapy device.", "author_names": [ "Dietrich Vastenburg", "Sjoerd Pet" ], "corpus_id": 18139909, "doc_id": "18139909", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "A follow up study on the morphology of isolated rat cortical neurons and information transferred via a \"biophoton device\"", "venue": "", "year": 2012 }, { "abstract": "Helices represent the most abundant secondary structure motif in proteins and are often involved in various functional roles. They are stabilized by a network of hydrogen bonds between main chain carbonyl and amide groups. Several surveys scrutinized these hydrogen bonds, mostly based on the geometry of the interaction. Alternatively, the topological analysis of the electron density provides a powerful technique to investigate hydrogen bonds. For the first time, transferred experimental charge density parameters (ELMAM database) were used to carry out a topological analysis of the electron density in protein helices. New parameters for the description of the hydrogen bond geometry are proposed. Bonding contacts between the amide N and carbonyl O atoms (N**O) of helices, poorly addressed in the literature so far, were characterized from topological, geometrical, and local energetic analyses. Particularly, a geometrical criterion allowing for the discrimination between hydrogen bonds and N**O contacts is proposed.", "author_names": [ "Dorothee Liebschner", "Christian Jelsch", "Enrique Espinosa", "Claude Lecomte", "Eric Chabriere", "Benoit Guillot" ], "corpus_id": 9373116, "doc_id": "9373116", "n_citations": 18, "n_key_citations": 1, "score": 0, "title": "Topological analysis of hydrogen bonds and weak interactions in protein helices via transferred experimental charge density parameters.", "venue": "The journal of physical chemistry. A", "year": 2011 }, { "abstract": "Thermodynamic limit of magnetization corresponding to the intact proton bath usually cannot be transferred in a single cross polarization contact. This is mainly due to the finite ratio between the number densities of the high and low gamma nuclei, quantum mechanical bounds on spin dynamics, and Hartmann Hahn mismatches due to rf field inhomogeneity. Moreover, for fully hydrated membrane proteins refolded in magnetically oriented bicelles, short spin lock relaxation times (T1r) and rf heating can further decrease cross polarization efficiency. Here we show that multiple equilibrations re equilibrations of the high and low spin reservoirs during the preparation period yield an over twofold gain in the magnetization transfer as compared to a single contact cross polarization (CP) and up to 45% enhancement as compared to the mismatch optimized CP MOIST scheme for bicelle reconstituted membrane proteins. This enhancement is achieved by employing the differences between the spin lattice relaxation times for the high and low gamma spins. The new technique is applicable to systems with short T1r's, and speeds up acquisition of the multidimensional solid state NMR spectra of oriented membrane proteins for their subsequent structural and dynamic studies.", "author_names": [ "Wenxing Tang", "Alexander A Nevzorov" ], "corpus_id": 5458661, "doc_id": "5458661", "n_citations": 26, "n_key_citations": 3, "score": 0, "title": "Repetitive cross polarization contacts via equilibration re equilibration of the proton bath: Sensitivity enhancement for NMR of membrane proteins reconstituted in magnetically aligned bicelles.", "venue": "Journal of magnetic resonance", "year": 2011 }, { "abstract": "Slow domains in oxygen doped n type GaAs with photoexcited conductivities ranging from 10 8 to 10 4 Omega CM) 1 have been investigated in the temperature range 100 to 200 K. It is proposed that the origin of these domains is the transferred electron effect with enhanced trapping from the (100) valley. The low threshold voltages are attributed to high resistance layers near the alloyed contacts of width about 10 mu m in low resistivity samples and about 100 mu m in high resistivity samples. A theoretical model is proposed for the domain incubation which invokes a sub nl product behaviour of the cathode layer and compared with experimental results of incubation time against applied field and the variation of threshold field with sample length. The trap modified drift velocity against field curve has been calculated from the results of Fawcett et al (1970) for the transferred electron effect in pure GaAs at 300K. The ratio of the capture time in the (000) valley to that in the '100) valley is estimated to be about thirty from the measured extra domain drift velocity, which was 4*105cm s 1 at temperatures around 150 K.", "author_names": [ "B K Ridley", "Jacob Crisp", "F Shishiyanu" ], "corpus_id": 123529782, "doc_id": "123529782", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Slow domains and negative resistance via the enhanced capture of transferred electrons in n type GaAs", "venue": "", "year": 1972 }, { "abstract": "The present study is dedicated to an experimental microkinetic approach of the catalyst oxidation of the diesel soot using a filter coated with ceria. To mimic the situation encountered in this process, mechanical ceria/soot mixtures have been prepared according to the tight and loose contact concepts described in the literature with ceria/soot ratio R 1. Diesel soots prepared on an engine test bench and commercial soot have been used. The evolution of the ceria/soot contacts (via the amount of oxygen transferred from ceria to soot) with the progressive oxidation of the soot is followed using temperature programmed experiments (denoted as TPEs) that provide the rate of CO2 and CO productions [denoted as RCO2(T) and RCO(T) during the increase in the temperature in helium in the range of 300 1100 K. During the first TPE, different surface processes implying pure soot and ceria contribute to RCO2(T) and RCO(T) making the evaluation of the oxygen transfer difficult. It is shown that these difficulties are.", "author_names": [ "Badr Bassou", "Nolven Guilhaume", "Karine Lombaert", "Claude Mirodatos", "Daniel Bianchi" ], "corpus_id": 96251020, "doc_id": "96251020", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Experimental Microkinetic Approach of the Catalytic Oxidation of Diesel Soot by Ceria Using Temperature Programmed Experiments. Part 1: Impact and Evolution of the Ceria/Soot Contacts during Soot Oxidation", "venue": "", "year": 2010 }, { "abstract": "Type I interferon (IFN I) is critical for antiviral defense, and plasmacytoid dendritic cells (pDCs) are a predominant source of IFN I during virus infection. pDC mediated antiviral responses are stimulated upon physical contact with infected cells, during which immunostimulatory viral RNA is transferred to pDCs, leading to IFN production via the nucleic acid sensor TLR7. Using dengue, hepatitis C, and Zika viruses, we demonstrate that the contact site of pDCs with infected cells is a specialized platform we term the interferogenic synapse, which enables viral RNA transfer and antiviral responses. This synapse is formed via aLb2 integrin ICAM 1 adhesion complexes and the recruitment of the actin network and endocytic machinery. TLR7 signaling in pDCs promotes interferogenic synapse establishment and provides feed forward regulation, sustaining pDC contacts with infected cells. This interferogenic synapse may allow pDCs to scan infected cells and locally secrete IFN I, thereby confining a potentially deleterious response.", "author_names": [ "Sonia Assil", "Severin Coleon", "Congcong Dong", "Elodie Decembre", "Lee Sherry", "Omran Allatif", "Brian Webster", "Marlene Dreux" ], "corpus_id": 125079493, "doc_id": "125079493", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "Plasmacytoid Dendritic Cells and Infected Cells Form an Interferogenic Synapse Required for Antiviral Responses.", "venue": "Cell host microbe", "year": 2019 }, { "abstract": "Abstract Background Respiratory viruses on fomites can be transferred to sites susceptible to infection via contact by hands or other fomites. Methods Care for hospitalized patients with viral respiratory infections was observed in the patient room for 3 hour periods at an acute care academic medical center for over a 2 year period. One trained observer recorded the healthcare activities performed, contacts with fomites, and self contacts made by healthcare workers (HCWs) while another observer recorded fomite contacts of patients during the encounter using predefined checklists. Results The surface contacted by HCWs during the majority of visits was the patient (90% Environmental surfaces contacted by HCWs frequently during healthcare activities included the tray table (48% bed surface (41% bed rail (41% computer station (37% and intravenous pole (32% HCWs touched their own torso and mask in 32% and 29% of the visits, respectively. HCWs' self contacts differed significantly among HCW job roles, with providers and respiratory therapists contacting themselves significantly more times than nurses and nurse technicians (P .05) When HCWs performed only 1 care activity, there were significant differences in the number of patient contacts and self contacts that HCWs made during performance of multiple care activities (P .05) Conclusions HCWs regularly contact environmental surfaces, patients, and themselves while providing care to patients with infectious diseases, varying among care activities and HCW job roles. These contacts may facilitate the transmission of infection to HCWs and susceptible patients.", "author_names": [ "Linh T Phan", "Dayana Maita", "Donna C Mortiz", "Susan C Bleasdale", "Rachael M Jones" ], "corpus_id": 202569543, "doc_id": "202569543", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Environmental Contact and Self contact Patterns of Healthcare Workers: Implications for Infection Prevention and Control", "venue": "Clinical infectious diseases an official publication of the Infectious Diseases Society of America", "year": 2019 }, { "abstract": "During the evaluation of forensic DNA evidence in court proceedings, the emphasis previously placed on the source of the DNA is progressively shifting to the consideration of the activities resulting in its deposition. While direct contact and deposition may be a likely explanation, alternative scenarios involving DNA transfer through a secondary person or medium are important to consider. Here we assessed whether non self DNA, indirectly transferred via a handshake, could be detected on surfaces contacted by the opposing hand shaker after 15min, and considered the variables affecting its persistence in subsequent contacts. In general, the depositor of the handprint was the major contributor to DNA profiles collected from handprints placed on glass plates. Minor contributions from the opposing hand shaker (as a known contributor) were detected at a lower rate, decreasing as the number of contacted items increased post handshake. Delays in deposition also affected the detection of the opposing hand shaker, with a 15min delay between handshaking and contact resulting in the reduced presence, and corresponding LRs, of the known contributor. The handprint depositor was excluded from their own handprint on several occasions, including instances where the opposing hand shaker was not excluded from the same profile. Several factors appeared to strongly influence the detection of both the depositor and contributing individual involved in the handshake. The relative shedding ability of the pair had the largest effect, where good shedders (whether depositor or contributor) could swamp poor to moderate shedders, while the pairing of two moderate or two poor shedders could result in the detection of both individuals. When the deposition of a handprint was delayed, the activities performed by the individual had a substantial effect on the resultant detection of the contributing profile multiple contacts with the same items increased the likelihood that the known contributor's DNA would be retained and subsequently detected, through the parking and re transfer of DNA on used items.", "author_names": [ "Bianca Szkuta", "Kaye N Ballantyne", "Roland A H van Oorschot" ], "corpus_id": 46834296, "doc_id": "46834296", "n_citations": 48, "n_key_citations": 3, "score": 0, "title": "Transfer and persistence of DNA on the hands and the influence of activities performed.", "venue": "Forensic science international. Genetics", "year": 2017 }, { "abstract": "The past decade has seen striking progress in our understanding of communication between organelles via close appositions of their membranes, known as contact sites. Recent systematic studies highlight that the cellular contact site landscape is much more intricate than previously anticipated and that most, if not all, organelles are capable of establishing such contacts with one another. Hence, the big challenge for this research field is to now step outside the comfort zone of the few highly studied examples of contact sites and a handful of molecules that are transferred at these sites, and to investigate the diversity of organelle contacts and the plethora of their cellular roles.Cellular organelles extensively communicate with each other by close interactions, known as membrane contact sites. Schuldiner and Bohnert comment on the progress of this rapidly developing field, highlighting that the complexity of interactions at membrane contact sites is only now starting to emerge.", "author_names": [ "Maria Bohnert", "Maya Schuldiner" ], "corpus_id": 21727731, "doc_id": "21727731", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Stepping outside the comfort zone of membrane contact site research", "venue": "Nature Reviews Molecular Cell Biology", "year": 2018 } ]

[ { "abstract": "Solution processing of metal oxides has been the focal point of interest for many researchers mainly because of the cost effectiveness and improved properties of metal oxides. However, achieving uniform and high quality film deposition has been a recurring challenge using various wet chemical techniques. Herein, we report a fully solution based fabrication process exploiting both the ultrasonic spray pyrolysis (USP) and spin coating techniques owing to their simplicity, high degree of freedom for mixing metal oxide precursor salt, and larger area deposition. An amorphous zirconium oxide (ZrOx) dielectric and zinc tin oxide (ZTO) semiconductor were deposited, respectively. The dielectric characteristics of the ZrOx thin films were accessed by fabricating MIS devices for the samples deposited at 200 degC and 400 degC, which exhibited a capacitance of 0.35 and 0.67 mF cm 2 at 100 kHz and relative permittivity of 8.5 and 22.7, respectively. The ZrOx thin film was then integrated as the gate dielectric layer in ZTO solution processed thin film transistors, exhibiting a high electrical performance with low hysteresis 0.18 V) high on/off current ratio of 106 orders of magnitude, saturation mobility of 4.6 cm2 V s 1, subthreshold slope of 0.25 V dec 1, and operating at a low voltage window of 3 V. Based on these results, the as fabricated ZTO/ZrOx TFT opens the potential application of solution processed transistors for low cost electronic devices.", "author_names": [ "Abayomi T Oluwabi", "Atanas Katerski", "E Carlos", "Rita Branquinho", "Arvo Mere", "Malle Krunks", "Elvira Fortunato", "Luis Pereira", "Ilona Oja Acik" ], "corpus_id": 214381751, "doc_id": "214381751", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Application of ultrasonic sprayed zirconium oxide dielectric in zinc tin oxide based thin film transistor", "venue": "", "year": 2020 }, { "abstract": "The fully inkjet printed top gate metal oxide thin film transistors (TFTs) with excellent electrical performance are realized with the gate dielectric layer of scandium zirconium oxide (Sc₁Zr₁O<sub><italic>x</italic>/sub> It is found that adding of nitrate based scandium oxide (ScO<sub><italic>x</italic>/sub> precursor into the chloride ligand based zirconium oxide (ZrO<sub><italic>x</italic>/sub> precursor will reduce the corrosivity of the mixed solution, and the incorporation of Zr ions into ScO<sub><italic>x</italic>/sub> will suppress the hydrogen ion migration and eliminate the acceptor like traps in pure ScO<sub><italic>x</italic>/sub> The fully printed indium gallium oxide (InGaO) TFTs based on Sc₁Zr₁O<sub><italic>x</italic>/sub> dielectric exhibited an average mobility of 10.8 cm<inline formula> <tex math notation=\"LaTeX\"{2} \\text{V}\\vphantom {R^ {1} \\cdot \\text{s} {1} /tex math>/inline formula> a highest mobility of 12.9 cm<inline formula> <tex math notation=\"LaTeX\"{2} \\cdot \\text{V} {1} \\cdot \\text{s} {1} /tex math>/inline formula> negligible hysteresis, and excellent stability under both the negative and positive bias stresses. In addition, a resistor loaded inverter was fabricated using a fully printed InGaO TFT, which exhibited the full swing characteristics and a maximum gain of 5 at 2 V.", "author_names": [ "Yuzhi Li", "Linfeng Lan", "Shiben Hu", "Peixiong Gao", "Xingqiang Dai", "Penghui He", "Xifeng Li", "Junbiao Peng" ], "corpus_id": 56717572, "doc_id": "56717572", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Fully Printed Top Gate Metal Oxide Thin Film Transistors Based on Scandium Zirconium Oxide Dielectric", "venue": "IEEE Transactions on Electron Devices", "year": 2019 }, { "abstract": "Solution processed metal oxides require a great deal of thermal budget in order to achieve the desired film properties. Here, we show that the deposition temperature of sprayed zirconium oxide (ZrOx) thin film can be lowered by exposing the film surface to an ultraviolet (UV) ozone treatment at room temperature. Atomic force microscopy reveals a smooth and uniform film with the root mean square roughness reduced from 0.63 nm (UVO O) to 0.28 nm (UVO 120) in the UV ozone treated ZrOx films. X ray photoelectron spectroscopy analysis indicates the formation of a Zr O network on the surface film, and oxygen vacancy is reduced in the ZrOx lattice by increasing the UV ozone treatment time. The leakage current density in Al/ZrOx/p Si structure was reduced by three orders of magnitude by increasing the UV ozone exposure time, while the capacitance was in the range 290 266 nF/cm2, corresponding to a relative permittivity (k) in the range 5.8 6.6 at 1 kHz. An indium gallium zinc oxide (IGZO) based thin film transistor, employing a UV treated ZrOx gate dielectric deposited at 200 degC, exhibits negligible hysteresis, an Ion/Ioff ratio of 104, a saturation mobility of 8.4 cm2 V 1S 1, a subthreshold slope of 0.21 V.dec 1, and a Von of 0.02 V. These results demonstrate the potentiality of low temperature sprayed amorphous ZrOx to be applied as a dielectric in flexible and low power consumption oxide electronics.", "author_names": [ "Abayomi T Oluwabi", "Diana Patricia Rodrigues Gaspar", "Atanas Katerski", "Arvo Mere", "Malle Krunks", "Luis Pereira", "Ilona Oja Acik" ], "corpus_id": 209433464, "doc_id": "209433464", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Influence of Post UV/Ozone Treatment of Ultrasonic Sprayed Zirconium Oxide Dielectric Films for a Low Temperature Oxide Thin Film Transistor", "venue": "Materials", "year": 2019 }, { "abstract": "Abstract Hafnium zirconium oxide (HZO) is promising for applications in future memory devices and energy storage and harvesting. While many studies have focused upon the dielectric and structural properties of HZO, much less investigated are their thermal properties, particularly in thin film form. We present the first report on the thermal conductivity of plasma enhanced atomic layer deposited (PEALD) HZO thin films. Steady state thermoreflectance measures the effective thermal conductivity of undoped and yttrium doped HZO films and their interfaces. The effective thermal conductivity of the undoped film is found to be 0.75 W m 1 K 1, which is comparable to those reported previously for thermal ALD HZO films with similar composition. With increasing yttrium doping level, the effective thermal conductivity slightly decreases down to 0.67 W m 1 K 1 owing to dopant scattering of phonons. Our PEALD HZO films are nanocrystalline as observed by grazing incidence X ray diffraction and transmission electron microscopy.", "author_names": [ "Jihyun Kim", "Sungje Lee", "Yiwen Song", "Sukwon Choi", "Jihwan An", "Jungwan Cho" ], "corpus_id": 234268560, "doc_id": "234268560", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Thermal conductivity of plasma enhanced atomic layer deposited hafnium zirconium oxide dielectric thin films", "venue": "", "year": 2021 }, { "abstract": "We demonstrated solution processed thin film transistors on a peroxo zirconium oxide (ZrO(2) dielectric with a maximum temperature of 350 degC. The formation of ZrO(2) films was investigated by TG DTA, FT IR, and XPS analyses at various temperatures. We synthesized a zirconium oxide solution by adding hydrogen peroxide (H(2)O(2) The H(2)O(2) forms peroxo groups in the ZrO(2) film producing a dense amorphous phase and a smooth surface film. Because of these characteristics, the ZrO(2) film successfully blocked leakage current even in annealing at 300 degC. Finally, to demonstrate that the ZrO(2) film is dielectric, we fabricated thin film transistors (TFTs) with a solution processed channel layer of indium zinc oxide (IZO) on ZrO(2) films at 350 degC. These TFTs had a mobility of 7.21 cm(2)(V s) a threshold voltage (V(th) of 3.22 V, and a V(th) shift of 1.6 V under positive gate bias stress.", "author_names": [ "Jeehong Park", "Young Bum Yoo", "Keun Ho Lee", "Woo Soon Jang", "Jin Young Oh", "Soo Sang Chae", "Hong Koo Baik" ], "corpus_id": 27003006, "doc_id": "27003006", "n_citations": 141, "n_key_citations": 1, "score": 1, "title": "Low temperature, high performance solution processed thin film transistors with peroxo zirconium oxide dielectric.", "venue": "ACS applied materials interfaces", "year": 2013 }, { "abstract": "Abstract A simple, facile surface sol gel method is introduced for the fabrication of zirconium oxide films for use as a dielectric layer of a solution processed polymer field effect transistor (PFET) High dielectric strength is demonstrated for a zirconium oxide layer under room temperature fabrication conditions using a surface sol gel method without any post treatments, which are typically needed in general sol gel methods. X ray photoemission spectroscopy showed that the fabricated zirconium oxide layer consists of inorganic ZrO2 and organic alkoxide groups, which can explain its marginal dielectric constant ~9) and continuous film properties. In addition, by finishing the surface sol gel synthesis at the stage of chemisorption, the hydrophobic nature of the final surface was retained, leading to a trap free semiconductor/dielectric interface. As a result, the PFET made with a conventional polymeric semiconductor rendered nearly hysteresis free and high mobility (0.3 cm2/V) characteristics at low voltage", "author_names": [ "Byung Tack Lim", "Jangwhan Cho", "Kwang Hee Cheon", "Kyu Min Sim", "Kwonwoo Shin", "Dae Sung Chung" ], "corpus_id": 93189982, "doc_id": "93189982", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Zirconium oxide dielectric layer grown by a surface sol gel method for low voltage, hysteresis free, and high mobility polymer field effect transistors", "venue": "", "year": 2016 }, { "abstract": "We developed a solution processed indium oxide (In2O3) thin film transistor (TFT) with a boron doped peroxo zirconium (ZrO2:B) dielectric on silicon as well as polyimide substrate at 200 degC, using water as the solvent for the In2O3 precursor. The formation of In2O3 and ZrO2:B films were intensively studied by thermogravimetric differential thermal analysis (TG DTA) attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT IR) high resolution X ray diffraction (HR XRD) and X ray photoelectron spectroscopy (XPS) Boron was selected as a dopant to make a denser ZrO2 film. The ZrO2:B film effectively blocked the leakage current at 200 degC with high breakdown strength. To evaluate the ZrO2:B film as a gate dielectric, we fabricated In2O3 TFTs on the ZrO2:B dielectrics with silicon substrates and annealed the resulting samples at 200 and 250 degC. The resulting mobilities were 1.25 and 39.3 cm(2)(V s) respectively. Finally, we realized a flexible In2O3 TFT with the ZrO2:B dielectric on a polyimide substrate at 200 degC, and it successfully operated a switching device with a mobility of 4.01 cm(2)(V s) Our results suggest that aqueous solution processed In2O3 TFTs on ZrO2:B dielectrics could potentially be used for low cost, low temperature, and high performance flexible devices.", "author_names": [ "Jeehong Park", "Young Bum Yoo", "Keun Ho Lee", "Woo Soon Jang", "Jin Young Oh", "Soo Sang Chae", "Hyun Woo Lee", "Sun Woong Han", "Hong Koo Baik" ], "corpus_id": 206783950, "doc_id": "206783950", "n_citations": 93, "n_key_citations": 0, "score": 0, "title": "Boron doped peroxo zirconium oxide dielectric for high performance, low temperature, solution processed indium oxide thin film transistor.", "venue": "ACS applied materials interfaces", "year": 2013 }, { "abstract": "In this paper, zirconium aluminum oxide (ZAO) dielectric layers were prepared by a solution method with intent to combine the high dielectric constant with a low leakage current density. As a result, dielectric layers with improved electrical properties as expected can be obtained by spin coating the mixed precursor. The chemical and physical properties of the films were measured by thermogravimetric differential scanning calorimetry (TG DSC) X ray diffraction (XRD) X ray photoelectron spectroscopy (XPS) and a UV spectrometer. It is observed that the oxygen defects and the hydroxide in the films are reduced with the addition of high bond energy zirconia, while the films can remain large optical bond gaps thanks to the presence of alumina. The metal insulator metal (MIM) devices were fabricated, and it was seen that with a molar ratio of Zr:Al 3:1 and an annealing temperature of 500 degC, the dielectric layer afforded the highest dielectric constant of 21.1, as well as a relatively low leakage current of 2.5 10 6 A/cm2@1MV/cm. Furthermore, the indium gallium zinc oxide thin film transistors (IGZO TFTs) with an optimal ZAO dielectric layer were prepared by the solution method and a mobility of 14.89 cm2/Vs, and a threshold voltage swing of 0.11 V/dec and a 6.1 106 on/off ratio were achieved at an annealing temperature of 500 degC.", "author_names": [ "Zhihao Liang", "Honglong Ning", "Junlong Chen", "Rihui Yao", "Junbiao Peng" ], "corpus_id": 216445934, "doc_id": "216445934", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Zirconium Aluminum Oxide Dielectric Layer with High Dielectric and Relatively Low Leakage Prepared by Spin Coating and the Application in Thin Film Transistor", "venue": "", "year": 2020 }, { "abstract": "Fin typed field effect transistor (FinFET) has considered a suitable device for low power and high performance applications. The incorporation of gate dielectric lanthanum doped zirconium oxide (LaZrO2) in the 14 nm silicon on insulator (SOI) FinFET not only enhanced effective carrier mobility but also diminished the short channel effects (SCEs) The FinFET embodiment with LaZrO2 has dwindled subthreshold swing (SS) reduced drain induced barrier lowering (DIBL) and raised on current to off current ratio as a contrast to SiO2 based FinFET. A remarkable enhancement of 1.18x, 11x, and 1.3x for transconductance (gm) early voltage (VEA) and an intrinsic gain (AV) respectively, have been investigated. Further, LaZrO2 based n FinFET and p FinFET devices have devised with equal dimensions. The improved noise margin of 0.375 V using a single fin FinFET based inverter circuit has proven the acceptance of this device in a circuit application.", "author_names": [ "Gurpurneet Kaur", "Sandeep Singh Gill", "Munish Rattan" ], "corpus_id": 227223237, "doc_id": "227223237", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Impact of lanthanum doped zirconium oxide (LaZrO2) gate dielectric material on FinFET inverter", "venue": "", "year": 2020 }, { "abstract": "In recent years, significant efforts have been devoted to the research and development of spin coated Al2O3 thin films, due to their large band gaps, high breakdown voltage and stability at high annealing temperature. However, as the alumina precursor has a large surface energy, substrates need to be treated by plasma before spin coating. Therefore, to avoid the expensive and process complicated plasma treatment, we incorporated zirconium nitrate into the aluminum nitrate solution to decrease the surface energy of the precursor which improve the spreadability. Then, the electrical performances and the surface morphologies of the films were measured. For comparison, the pure Al2O3 films with plasma treatments were also prepared. As a result, after low temperature annealing (200 degC) the relative dielectric constant of Zr AlOx spin coated thin film MIM (Metal Insulator Metal) devices can reach 12 and the leakage current density is not higher than 7.78 x 10 8 A/cm2 1 MV/cm when the concentration of zirconium nitrate is 0.05 mol/L. The Aluminum oxide film prepared by zirconium doping has higher stability and better electrical properties than the pure films with plasma treatments and high performance can be attained under low temperature annealing, which shows its potential application in printing and flexible electronic devices.", "author_names": [ "Yuewei Zhou", "Zhihao Liang", "Rihui Yao", "Wencai Zuo", "Yiping Wang", "Tian Qiu", "Honglong Ning", "Junbiao Peng" ], "corpus_id": 225731475, "doc_id": "225731475", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Effect of Zirconium Doping on Electrical Properties of Aluminum Oxide Dielectric Layer by Spin Coating Method with Low Temperature Preparation", "venue": "", "year": 2020 } ]

[ { "abstract": "With the globalization of the semiconductor manufacturing process, electronic devices are powerless against malicious modification of hardware in the supply chain. The ever increasing threat of hardware Trojan attacks against integrated circuits has spurred a need for accurate and efficient detection methods. Ring oscillator network (RON) is used to detect the Trojan by capturing the difference in power consumption; the power consumption of a Trojan free circuit is different from the Trojan inserted circuit. However, the process variation and measurement noise are the major obstacles to detect hardware Trojan with high accuracy. In this paper, we quantitatively compare four supervised machine learning algorithms and classifier optimization strategies for maximizing accuracy and minimizing the false positive rate (FPR) These supervised learning techniques show an improved false positive rate compared to principal component analysis (PCA) and convex hull classification by nearly 40% while maintaining 90% binary classification accuracy.", "author_names": [ "Kyle Worley", "Md Tauhidur Rahman" ], "corpus_id": 75135008, "doc_id": "75135008", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Supervised Machine Learning Techniques for Trojan Detection with Ring Oscillator Network", "venue": "2019 SoutheastCon", "year": 2019 }, { "abstract": "Abstract Atomic layer deposition (ALD) is a widely utilized deposition technology in the semiconductor industry due to its superior ability to generate highly conformal films and to deposit materials into high aspect ratio geometric structures. However, ALD experiments remain expensive and time consuming, and the existing first principles based models have not yet been able to provide solutions to key process outputs that are computationally efficient, which is necessary for on line optimization and real time control. In this work, a multiscale data driven model is proposed and developed to capture the macroscopic process domain dynamics with a linear parameter varying model, and to characterize the microscopic domain film growth dynamics with a feed forward artificial neural network (ANN) model. The multiscale data driven model predicts the transient deposition rate from the following four key process operating parameters that can be manipulated, measured or estimated by process engineers: precursor feed flow rate, operating pressure, surface heating, and transient film coverage. Our results demonstrate that the multiscale data driven model can efficiently characterize the transient input output relationship for the SiO2 thermal ALD process using bis(tertiary butylamino)silane (BTBAS) as the Si precursor. The multiscale data driven model successfully reduces the computational time from 0.6 to 1.2 h for each time step, which is required for the first principles based multiscale computational fluid dynamics (CFD) model, to less than 0.1 s, making its real time usage feasible. The developed data driven modeling methodology can be further generalized and used for other thermal ALD or similar deposition systems, which will greatly enhance the feasibility of industrial manufacturing processes.", "author_names": [ "Yangyao Ding", "Yichi Zhang", "Yi Ming Ren", "Gerassimos Orkoulas", "Panagiotis D Christofides" ], "corpus_id": 203141299, "doc_id": "203141299", "n_citations": 20, "n_key_citations": 1, "score": 0, "title": "Machine learning based modeling and operation for ALD of SiO2 thin films using data from a multiscale CFD simulation", "venue": "Chemical Engineering Research and Design", "year": 2019 }, { "abstract": "In this paper, we present a novel interpretable machine learning technique that uses unique physical insights about noisy optical images and a few training samples to classify nanoscale defects in noisy optical images of a semiconductor wafer. Using this technique, we not only detected both parallel bridge defects and previously undetectable perpendicular bridge defects in a 9 nm node wafer using visible light microscopy [Proc. SPIE 9424, 942416 (2015) but we also accurately classified their shapes and estimated their sizes. Detection and classification of nanoscale defects in optical images is a challenging task. The quality of images is affected by diffraction and noise. Machine learning techniques can reduce noise and recognize patterns using a large training set. However, for detecting a rare \"killer\" defect, acquisition of a sufficient training set of high quality experimental images can be prohibitively expensive. In addition, there are technical challenges involved in using electromagnetic simulations and optimization of the machine learning algorithm. This paper proposes solutions to address each of the aforementioned challenges. (c) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement", "author_names": [ "" ], "corpus_id": 201686276, "doc_id": "201686276", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optical inspection of nanoscale structures using a novel machine learning based synthetic image generation algorithm", "venue": "", "year": 2019 }, { "abstract": "A Boltzmann machine whose effective \"temperature\" can be dynamically \"cooled\" provides a stochastic neural network realization of simulated annealing, which is an important metaheuristic for solving combinatorial or global optimization problems with broad applications in machine intelligence and operations research. However, the hardware realization of the Boltzmann stochastic element with \"cooling\" capability has never been achieved within an individual semiconductor device. Here we demonstrate a new memristive device concept based on two dimensional material heterostructures that enables this critical stochastic element in a Boltzmann machine. The dynamic cooling effect in simulated annealing can be emulated in this multi terminal memristive device through electrostatic bias with sigmoidal thresholding distributions. We also show that a machine learning based method is efficient for device circuit co design of the Boltzmann machine based on the stochastic memristor devices in simulated annealing. The experimental demonstrations of the tunable stochastic memristors combined with the machine learning based device circuit co optimization approach for stochastic memristor based neural network circuits chart a pathway for the efficient hardware realization of stochastic neural networks with applications in a broad range of electronics and computing disciplines.", "author_names": [ "Tong Wu", "Huan Zhao", "Fanxin Liu", "Jing Guo", "Han Wang" ], "corpus_id": 165019847, "doc_id": "165019847", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Tunable Stochastic Memristive Device for Simulated Annealing in Boltzmann Machine Designed by a Machine Learning Method", "venue": "", "year": 2019 }, { "abstract": "Due to the increasing complexity of semiconductor industry, the traditional rule based technology has faced its limits in solving Electronic Design Automation (EDA) problems, which have high dimensionality, discontinuous, and non linearities. Instead, machine learning (ML) has been in rapidly growing demand, and has been gradually involved in EDA applications [1] This talk shares several industrial applications of ML, including commercial EDA tools, and the great opportunity to expand the use of ML solution for design flow optimization as well.", "author_names": [ "Laura Wang", "Matt Luo" ], "corpus_id": 195224261, "doc_id": "195224261", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Machine Learning Applications and Opportunities in IC Design Flow", "venue": "2019 International Symposium on VLSI Design, Automation and Test (VLSI DAT)", "year": 2019 }, { "abstract": "IC Design has been an industry which provides flexible application specific integrated circuit (ASIC) services enabling semiconductor manufacturing companies for flexible decision. Although the industry influences semiconductor supply chain significantly, capacity portfolio and planning issues of IC design industry is seldom mentioned in the past studies. For IC design service industry, the main productivity denotes to IC design which is influenced by the performance of project management from workforce allocation. The purpose of this study is to develop an intelligent agent to predict the workforce required for each wafer production service project, and thus based on the prediction, the intelligent agent is able to provide an IC design service company with workforce allocation strategy. Featuring learning algorithms and analyzing from the existing data, the study trains a XG Boosting model combining Genetic Algorithm based parameter optimization mechanism. The proposed intelligent agent contributes to Total Resource Management (TRM) to enhance productivity, reduce costs and intelligence management.", "author_names": [ "Chieh Hsu", "", "Andy Y F Kuo", "Ju-Chien Chien", "Wenhan Fu", "Kang-Ting Ma", "Chen-Fu Chien" ], "corpus_id": 204843500, "doc_id": "204843500", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Machine Learning based Intelligent Agent for Human Resource Planning in IC Design Service Industry", "venue": "", "year": 2019 }, { "abstract": "Background Over the past decade, machine learning techniques have revolutionized how research and science are done, from designing new materials and predicting their properties to data mining and analysis to assisting drug discovery to advancing cybersecurity. Recently, we added to this list by showing how a machine learning algorithm (a so called learner) combined with an optimization routine can assist experimental efforts in the realm of tuning semiconductor quantum dot (QD) devices. Among other applications, semiconductor quantum dots are a candidate system for building quantum computers. In order to employ QDs, one needs to tune the devices into a desirable configuration suitable for quantum computing. While current experiments adjust the control parameters heuristically, such an approach does not scale with the increasing size of the quantum dot arrays required for even near term quantum computing demonstrations. Establishing a reliable protocol for tuning QD devices that does not rely on the gross scale heuristics developed by experimentalists is thus of great importance. Materials and methods To implement the machine learning based approach, we constructed a dataset of simulated QD device characteristics, such as the conductance and the charge sensor response versus the applied electrostatic gate voltages. The gate voltages are the experimental 'knobs' for tuning the device into useful regimes. Here, we describe the methodology for generating the dataset, as well as its validation in training convolutional neural networks. Results and discussion From 200 training sets sampled randomly from the full dataset, we show that the learner's accuracy in recognizing the state of a device is 96.5% when using either current based or charge sensor based training. The spread in accuracy over our 200 training sets is 0.5% and 1.8% for current and charge sensor based data, respectively. In addition, we also introduce a tool that enables other researchers to use this approach for further research: QFlow lite a Python based mini software suite that uses the dataset to train neural networks to recognize the state of a device and differentiate between states in experimental data. This work gives the definitive reference for the new dataset that will help enable researchers to use it in their experiments or to develop new machine learning approaches and concepts.", "author_names": [ "Justyna P Zwolak", "Sandesh S Kalantre", "Xingyao Wu", "Stephen Ragole", "Jacob M Taylor" ], "corpus_id": 52986279, "doc_id": "52986279", "n_citations": 14, "n_key_citations": 2, "score": 0, "title": "QFlow lite dataset: A machine learning approach to the charge states in quantum dot experiments", "venue": "PloS one", "year": 2018 }, { "abstract": "As feature resolution and process variations continue to shrink for new nodes of both DUV and EUV lithography, the density and number of devices on advanced semiconductor masks continue to increase rapidly. These advances cause significantly increased pressure on the accuracy and efficiency of OPC and assist feature (AF) optimization methods for each subsequent process technology. Several publications and industry presentations have discussed the use of neural networks or other machine learning techniques to provide improvements in efficiency for OPC main feature optimization or AF placement. In this paper, we present results of a method for using machine learning to predict OPC mask segment displacements. We will review several detailed examples showing the accuracy and overall OPC TAT benefits of our method for advanced node manufacturing test cases. We will also discuss the experiments testing the amount and diversity of training data required to achieve true production level OPC stability.", "author_names": [ "Hesham M Abdelghany", "Kevin Hooker", "Marco Guajardo", "Chia-Chun Lu" ], "corpus_id": 216440154, "doc_id": "216440154", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Implementing Machine Learning OPC on product layouts", "venue": "", "year": 2020 }, { "abstract": "Maximizing yield in a modern semiconductor fab requires proper optimization of the design (layout) process technology, and fab process tool recipes. For the past decade the prevalence of systematic defects tied to design or design process interactions have predominated over random defect sources. Previously Resolution Enhancement Technology (RET) Design For Manufacturability (DFM) and Design Technology Co optimization (DTCO) techniques were the successful response to eliminating systematic yield limiting patterns. Machine learning, with its ability to find trends and make predictions based on large volumes of data, provides a unique path towards further reduction in systematic defect levels. This talk will present methods based on the use of design and process info with machine learning and computational lithography methods to identify and eliminate yield limiting patterns in the design, improve the accuracy of mask generation with etch and resist modeling and OPC, and improve the productivity and accuracy of fab defect detection and diagnostics. This paper will present methods to improve EPE control and reduce systematic hotspots through both supervised and unsupervised machine learning. Specifically we will focus on 3 areas: identifying and yield limiting patterns in the design phase. improving the accuracy (EPE control) of mask generation with machine learning assisted etch and resist modeling and OPC. improving the productivity and accuracy of fab defect detection and diagnostics with machine learning.", "author_names": [ "Yuansheng Ma", "Le Van Hong", "James C Word", "Fan Jiang", "Vlad Liubich", "Liang Cao", "Srividya Jayaram", "Doohwan Kwak", "Youngchang Kim", "Germain Fenger", "Ananthan Raghunathan", "Joerg Mellmann" ], "corpus_id": 216530770, "doc_id": "216530770", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Reduction of systematic defects with machine learning from design to fab", "venue": "Advanced Lithography", "year": 2020 }, { "abstract": "As feature resolution and process variations continue to shrink for new nodes of both DUV and EUV lithography, the density and number of devices on advanced semiconductor masks continue to increase rapidly. These advances cause significantly increased pressure on the accuracy and efficiency of OPC and assist feature (AF) optimization methods for each subsequent process technology. To meet manufacturing yield requirements, significant wafer retargeting from the original design target is often performed before OPC to account for both lithographic limitations and etch effects. As retargeting becomes more complex and important, rule table based approaches become ineffective. Alternatively, modelbased optimization approaches using advanced solvers, e.g. inverse lithography technology (ILT) have demonstrated process window improvement over rule based approaches. However, model based target optimization is computationally expensive which typically limits its use to smaller areas like hotspot repairs. In this paper, we present results of a method that uses machine learning (ML) to predict optimal retargeting for line space layers. In this method, we run ILT co optimization of the wafer target and process window to generate the training data used to train a machine learning model to predict the optimum wafer target. We explore methods to avoid ML model overfitting and show the ML infrastructure used to integrate ML solution into a manufacturable OPC flow. Both lithographic quality and runtime performance are evaluated for an ML enabled retargeting flow, an ILT flow and a simple rule table flow at advanced node test cases.", "author_names": [ "Kevin Hooker", "Marco Guajardo", "Nai-Chia Cheng", "Guangming Xiao" ], "corpus_id": 216461593, "doc_id": "216461593", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Implementing Machine Learning for OPC retargeting", "venue": "", "year": 2020 } ]

[ { "abstract": "Graphene is considered as one of the most promising materials for post silicon electronics, as it combines high electron mobility with atomic thickness [Novoselov et al. Science 2004, 306, 666 669. Novoselov et al. Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 10451 10453] The possibility of chemical doping and related excellent chemical sensor properties of graphene have been demonstrated experimentally [Schedin et al. Nat. Mater. 2007, 6, 652 655] but a microscopic understanding of these effects has been lacking, so far. In this letter, we present the first joint experimental and theoretical investigation of adsorbate induced doping of graphene. A general relation between the doping strength and whether adsorbates are open or closed shell systems is demonstrated with the NO2 system: The single, open shell NO2 molecule is found to be a strong acceptor, whereas its closed shell dimer N2O4 causes only weak doping. This effect is pronounced by graphene's peculiar density of states (DOS) which provides an ideal situation for model studies of doping effects in semiconductors. We show that this DOS is ideal for \"chemical sensor\" applications and explain the recently observed [Schedin et al. Nat. Mater. 2007, 6, 652 655] NO2 single molecule detection.", "author_names": [ "Tim Oliver Wehling", "Kostya S Novoselov", "S V Morozov", "Evgenii E Vdovin", "Mikhail I Katsnelson", "Andre K Geim", "Alexander I Lichtenstein" ], "corpus_id": 38836029, "doc_id": "38836029", "n_citations": 864, "n_key_citations": 6, "score": 1, "title": "Molecular doping of graphene.", "venue": "Nano letters", "year": 2008 }, { "abstract": "One of the most exciting recent developments in nanoscience was the discovery of graphene (single sheets of carbon atoms, a two dimensional \"(2D) crystal\" and the subsequent discovery of the fascinating properties of this new material, e.g. electrons behaving as massless relativistic particles and an anomalous quantum Hall effect [A. K. Geim and K. S. Novoselov, Nat. Mater. 6, 183 (2007) It is also surprising that large sheets of graphene exist as it was widely believed that 2D crystals are unstable. Furthermore, because of the stability of folded graphene sheets, i.e. carbon nanotubes (CNTs) a fascinating question is why does not graphene spontaneously transform into CNTs? In this paper, we explore the thermal stability of small pieces of graphene, i.e. graphene nanoflakes by ab initio quantum mechanical techniques. We find that indeed nanoflakes are stable to being heated and do not under any conditions used here transform to CNTs. They do not, however, remain strictly 2D as at finite temperatures, they undergo extensive vibrational motion and remain buckled if annealed and then quenched to room temperature.", "author_names": [ "Amanda S Barnard", "I K Snook" ], "corpus_id": 35580856, "doc_id": "35580856", "n_citations": 69, "n_key_citations": 0, "score": 0, "title": "Thermal stability of graphene edge structure and graphene nanoflakes.", "venue": "The Journal of chemical physics", "year": 2008 }, { "abstract": "Graphene is a single layer of carbon atoms that offer a unique set of advantages as a chemical sensor due to a number of its inherent properties. Graphene has been explored as a gas sensor for a variety of gases, and molecular sensitivity has been demonstrated by measuring the change in electrical properties due to the adsorption of target species (Schedin, F. Geim, A.K. Morozov, S.V. Hill, E.W. Blake, P. Katsnelson, M.I. Novoselov, K.S. Nat. Mater 2007, 6, 652 655. doi:10.1038/nmat1967) In this paper, we discuss the development of an array of chemical sensors based on graphene and its relevance to plasma physics due to its sensitivity to radical species such as O+ H+ and the corresponding neutrals. We briefly discuss the great impact such sensors will have on a number of heliophysics applications such as ground based manifestations of space weather.", "author_names": [ "Mahmooda Sultana", "Fred A Herrero", "George V Khazanov" ], "corpus_id": 95715416, "doc_id": "95715416", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Graphene chemical sensors for heliophysics applications", "venue": "", "year": 2013 }, { "abstract": "Lately, the integration of two dimensional materials into semiconductor devices has allowed the modification of their effective index by simply applying a modest voltage (between 0 and 3 volts) In this work, we present a device composed of two evanescently coupled silicon microring resonators where both rings have a graphene layer on top. This design is aimed to produce frequency combs with transmission characteristics controlled upon voltage application to the graphene layer. We numerically analyze the device response as a function of the incident wavelength and applied voltage. The results showed a low input intensity (0.6 GW/cm2) needed and a rapid response time (0.1 ms) in comparison to devices controlled by heat injection. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (130.0130) Integrated optics; (230.0230) Optical devices. (190.0190) Nonlinear optics. References and links 1. Z. Sun, A. Martinez, and F. Wang, \"Optical modulators with 2D layered materials,\" Nat. Photonics 10, 227 238 (2016) 2. T. Low, A. Chaves, J. D. Caldwell, A. Kumar, N. X. Fang, P. Avouris, T. F. Heinz, F. Guinea, L. Martin Moreno, and F. Koppens, \"Polaritons in layered two dimensional materials,\" Nat. Mater. 16, 182 (2017) 3. K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. 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Soc. 380, 839 847 (2007) 20. T. Steinmetz, T. Wilken, C. Araujo Hauck, R. Holzwarth, T. W. Hansch, L. Pasquini, A. Manescau, S. D'Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, \"Laser frequency combs for astronomical observations,\" Science 321, 1335 1337 (2008) 21. C. H. Li, A. J. Benedick, P. Fendel, A. G. Glenday, F. X. Kartner, D. F. Phillips, D. Sasselov, A. Szentgyorgyi, and R. L. Walsworth, \"A laser frequency comb that enables radial velocity measurements with a precision of 1 cm s 1,\" Nature 452, 610 612 (2008) 22. S. A. Diddams, L. Hollberg, and V. Mbele, \"Molecular fingerprinting with the resolved modes of a femtosecond laser frequency comb,\" Nature 445, 627 630 (2007) 23. C. Gohle, T. Udem, M. Herrmann, J. Rauschenberger, R. Holzwarth, H. A. Schuessler, F. Krausz, and T. W. Hansch, \"A frequency comb in the extreme ultraviolet,\" Nature 436, 234 237 (2005) 24. R. J. Jones, K. D. Moll, M. J. Thorpe, and J. Ye, \"Phase coherent frequency combs in the vacuum ultraviolet via high harmonic generation inside a femtosecond enhancement cavity,\" Phys. Rev. Lett. 94, 193201 (2005) 25. F. Keilmann, C. Gohle, and R. Holzwarth, \"Time domain mid infrared frequency comb spectrometer,\" Opt. Lett. 29, 1542 1544 (2004) 26. I. Coddington, W. C. Swann, L. Nenadovic, and N. R. Newbury, \"Rapid and precise absolute distance measurements at long range,\" Nat. Photonics 3, 351 356 (2009) 27. R. W. Boyd, Nonlinear optics (Academic Press, 2003) 28. G. P. Agrawal, Nonlinear fiber optics (Academic Press, 2007) 29. T. J. Kippenberg, R. Holzwarth, and S. Diddams, \"Microresonator based optical frequency combs,\" Science 332, 555 559 (2011) 30. T. Herr, K. Hartinger, J. Riemensberger, C. Wang, E. Gavartin, R. Holzwarth, M. Gorodetsky, and T. Kippenberg, \"Universal formation dynamics and noise of kerr frequency combs in microresonators,\" Nat. Photonics 6, 480 487 (2012) 31. A. A. Savchenkov, A. B. Matsko, V. S. Ilchenko, I. Solomatine, D. Seidel, and L. Maleki, \"Tunable optical frequency comb with a crystalline whispering gallery mode resonator,\" Phys. Rev. Lett. 101, 093902 (2008) 32. I. S. Grudinin, N. Yu, and L. Maleki, \"Generation of optical frequency combs with a caf 2 resonator,\" Opt. Lett. 34, 878 880 (2009) 33. W. Liang, A. Savchenkov, A. Matsko, V. Ilchenko, D. Seidel, and L. Maleki, \"Generation of near infrared frequency combs from a MgF2 whispering gallery mode resonator,\" Opt. Lett. 36, 2290 2292 (2011) 34. C. Wang, T. Herr, P. Del'Haye, A. Schliesser, R. Holzwarth, T. W. Haensch, N. Picque, and T. Kippenberg, \"Midinfrared frequency combs based on microresonators,\" in Proceedings of Optical Society of America Conference CLEO: Science and Innovations (Optical Society of America, 2011) p. PDPA4. 35. I. H. Agha, Y. Okawachi, M. A. Foster, J. E. Sharping, and A. L. Gaeta, \"Four wave mixing parametric oscillations in dispersion compensated high q silica microspheres,\" Phys. 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Quantum Electron. 23, 1 6 (2017) 41. P. A. Costanzo Caso, Y. Jin, S. Granieri, and A. Siahmakoun, \"Optical bistability in a nonlinear soa based fiber ring resonator,\" J. Nonlinear Opt. Phys. Mater.20, 281 292 (2011) 42. S. Rabal, L. A. Bulus Rossini, and P. A. Costanzo Caso, \"Control strategy of true time delay lines,\" Fiber Integrated Opt. 38, 38 58 (2016) 43. P. Del Haye, T. Herr, E. Gavartin, M. Gorodetsky, R. Holzwarth, and T. J. Kippenberg, \"Octave spanning tunable frequency comb from a microresonator,\" Phys. Rev. Lett. 107, 063901 (2011) 44. H. Jung, C. Xiong, K. Y. Fong, X. Zhang, and H. X. Tang, \"Optical frequency comb generation from aluminum nitride microring resonator,\" Opt. Lett. 38, 2810 2813 (2013) 45. X. Xue, Y. Xuan, P. H. Wang, J. Wang, D. E. Leaird, M. Qi, and A. M. Weiner, \"Tunable frequency comb generation from a microring with a thermal heater,\" in Proceedings of Optical Society of America Conference CLEO: Science Vol. 26, No. 12 11 Jun 2018 OPTICS EXPRESS 15491", "author_names": [ "", "Chadli A", "P V" ], "corpus_id": 53703060, "doc_id": "53703060", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Manipulation of extinction features in frequency combs through the usage of graphene", "venue": "", "year": 2018 }, { "abstract": "A decade after the discovery of grapheme by A.K. Geim and K.S. Novoselov manyof its fundamental properties have been intensely studied. Indeed, the early promise ofgrapheme has been kept, leading to a fruitful research in many felds as diverse as optics,mechanics, chemistry or electronics, and grapheme still deserves the name of wondermaterial as among its attributes there is an exceptionally good conduction of heat andelectricity, it is one of the strongest known material while being light and opticallytransparent. Its success was partly due to the easy micromechanical cleavage or scotchtape exfoliation technique accessible to any laboratory without heavy equipment, thatallowed to study the properties of grapheme with a wide range of experimental techniques.Following the success of grapheme, other two dimensional (2D) materials were obtainedwith the same technique, leading to a particularly rich physics.", "author_names": [ "Quentin Wilmart" ], "corpus_id": 124185691, "doc_id": "124185691", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Engineering doping profils in graphene from Dirac fermion oprtics to high frequency electronics", "venue": "", "year": 2015 }, { "abstract": "En 2004, un nouveau materiau, le graphene, a ete isole pour la premiere fois sur un substrat de SiO2, en utilisant une technique d'exfoliation mecanique par K.S. Novoselov et A.K. Geim Prix Nobels de Physique 2010. Ce materiau, qui presente des proprietes electriques et mecaniques extraordinaires, a suscite d'importants travaux de recherche. Des lors, differentes methodes de synthese du graphene sur des substrats de plus en plus grands sont developpees. C'est dans ce cadre que j'ai commence mes travaux de recherche en 2007, avec pour objectif de demontrer les potentialites des transistors a base de graphene, pour des applications hyperfrequences. Notre choix s'est oriente sur la synthese du graphene par graphitisation du SiC. Ces travaux se sont deroules en etroite collaboration avec le groupe EPIPHY en charge de la synthese du materiau, dans le cadre du projet ANR XP Graphene labellise en 2007, avec le soutien de ST Microeletronics. Apres avoir mis en evidence les proprietes du materiau ayant un impact sur les caracteristiques des transistors a effet de champ sur ce materiau, j'ai developpe au cours de ma these des procedes technologiques permettant de fabriquer des transistors sur ce type de materiau, ainsi qu'une procedure de caracterisation des differentes etapes technologiques. A titre d'exemple, un travail important a ete mene sur les aspects de la nanolithographie, de maniere a realiser de maniere courante des reseaux de nano rubans de largeur 20 nm, de longueur 1 um, et espaces de 40 nm. A l'issue de ma these, j'ai reussi a fabriquer et a caracteriser des transistors presentant des performances hyperfrefrences globales au meilleur niveau international.", "author_names": [ "Nan Meng" ], "corpus_id": 92797160, "doc_id": "92797160", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Fabrication et caracterisation de transistors a base de Graphene Nano Ruban en vue d'application haute frequence", "venue": "", "year": 2011 }, { "abstract": "Following the recents works of K.S. Novoselov and A.K. Geim [1] in 2004, the semiconductor industry has been attracted to carbon based technologies in order to maintain the trend on low cost and still reducible transistor structures. From circuit point of view, monolayer and bilayer Graphene FETs (GFETs) are being studied for high performance applications. Although monolayer graphene presents an energy band structure where there is no bandgap, its high thermal and electrical conductivity makes it suitable for high frequency applications. On the other hand, bilayer graphene presents a tunable bandgap by the application of an electric field perpendicular to the layer which allows the design of more flexible GFET structures. In this paper, we report the evidence of a tunable bandgap on bilayer graphene based on physical equations and the expected performances of these devices are compared with monolayer graphene FETs. The presented results are based on GFET structures with an HfO2 top gate dielectric (er 16) and a SiO2 back gate dielectric (er 3.9) as in [4] The gate length is fixed to 1 mm and the width to 2.1 mm. Residual carrier density npuddle is considered to be 1.5e12 cm 2 and the net doping concentration to 5e12 cm 2 Access resistances RS and RD are set to be equal to 100 O. Electron and hole mobilities are set to 1500 cm 2 /V s. For the simulations shown below, the effect of a tunable bandgap on a AB stacking bilayer graphene (Figure 1) due to the applied electric field has been taken into account. Figure 2 shows the low energy bands for bilayer graphene for two different values of the applied potential energy. When the applied potential energy is zero (U 0 eV) there is no bandgap (Egap 0) on the other hand when the applied potential energy is non zero (i.e. U 1 eV) the presence of a non zero energy band gap can be observed. Figure 3 shows the Energy band gap Egap under the average electrical displacement field generated by the applied bias voltages [2] A variation on Egap within [0 to 250 meV] can be noted. For the purpose of a comparative study, the monolayer and bilayer GFETs are compared via numerical simulations. Based on [3] and [4] a model for monolayer GFET has been developed where access resistances, the effect of puddles on carrier density and doping concentration are taken into account. In the case of bilayer GFETs a model based on physical equations [5] has been developed. Figure 4 shows a comparison of the IDS VGS plot for bilayer and monolayer GFETs under the same bias conditions VDS 1.5, 1.0, 0.5] V and a back gate voltage VBG 40 V. Higher currents on bilayer GFETs can be observed from Figure 4 and a higher transconductance gm reflecting a better current modulation in the channel by the gate voltage. Figure 5 shows the typical ID VDS characteristic for both bilayer and monolayer GFETs under the same bias conditions Vgs [0 to 3.0] V and VBG 40 V. Higher currents and higher output conductance gds are observed in the case of bilayer GFETs. The effect of a backgate voltage VBG is shown in Figure 6 from which it can be observed that the current modulation stays constant for all VBG as the ambipolar point (VDirac) moves along de x axis. Extraction of small signal parameters from both the GFETs allows us to calculate the cut off frequency fT as a function of gate length (Figure 7) Higher cut off frequencies, fT, can be observed for bilayer graphene for all gate lengths. Scaling down gate lengths for both bilayer and monolayer GFETs show an increase in fT. Thus, from our study, we can infer some important conclusions about the possible future of GFETs as bilayer graphene offers higher cut off frequencies and a tunable band gap over monolayer devices. Even if voltage gain (AV gm/gds) is higher in bilayer graphene FETs, it is still to be improved for future high performance applications.", "author_names": [ "Chhandak Mukherjee", "Sebastien Fregonese", "Cristell Maneux", "Thomas Zimmer" ], "corpus_id": 201696523, "doc_id": "201696523", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analytical Study of Performances of Monolayer and Bilayer Graphene FETs Based on Physical Mechanisms", "venue": "", "year": 2014 }, { "abstract": "Since Iijima discovered carbon nanotubes in 1991, many studies on the polymer nanocomposites has been mushroomed at recent years. Carbon nanotube has improved the physical properties of polymers. The mechanical properties of nanocomposites such as the elastic modulus, E, and the hardness, H has had a significant improvement. Then, in 2004, A.K. Geim and K.S. Novoselov separated graphene from graphite by mechanical cleavage, the extraordinary physical properties and ability to be dispersed in various polymer matrices has created a new field of polymer nanocomposites, an extensive research in the field has been initiated. In this study we investigate the influence of nano carbon reinforcements on mechanical properties of carbon nanotube/epoxy and graphene nanoplatelets/epoxy composites. Carbon nanotube (CNT) and expanded graphene nanoplatelets (EGNP) were dispersed within epoxy resins using a high pressure processor and a three roll milling. Characteristics on EGNPs/epoxy was confirmed with micro Raman spectroscopy. Nano indentation test was performed on the nano composites. The interction of CNT and EGNP improved the modulus and hardness of the composite. However, a significant increase of mechanical properties was seen at the low nano carbon content, but it is more and more difficult to disperse homogeneously with higher concentrations. Also the viscoelastic behavior of graphene nanoplatelets/epoxy composites is examined by the nano indentations test", "author_names": [ "" ], "corpus_id": 210206018, "doc_id": "210206018", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nai Mi Tan Guan /Huan Yang Shu Zhi Yu Shi Mo Xi /Huan Yang Shu Zhi Fu He Cai Liao Zhi Nai Mi Ya Hen Shi Yan Yan Jiu", "venue": "", "year": 2012 }, { "abstract": "Graphene, an atomically thin carbon monolayer, is a unique condensed matter system which shows the features predicted by relativistic quantum mechanics [1] Apart from merging the two rather distant elds of physics together, the world of graphene is also considered as a promissing environment for solid state quantum computing. We review the existing theoretical proposals for physical realization of a qubit in graphene nanostructures [2,3,4] which were recently followed by a remarkable progress in nanoribbon fabrication [5] The role of spontaneous magnetic order predicted for zigzag edge ribbons [4] is stressed. Finally, we present the original proposal for building graphene quantum dots by trapping electrons with the help of sublattice mismatch. [1] A.K. Geim and K.S. Novoselov, Nature Materials 6, 183 (2007) [2] B. Trauzettel, D.V. Bulaev, D. Loss, and G. Burkard, Nature Physics 3, 192 (2007) [3] A. Rycerz, J. TworzydAlo, and C.W.J. Beenakker, Nature Physics 3, 172 (2007) [4] M.Wimmer et al. arxiv:0709.3244; S.Dutta et al. Phys. Rev. B 77, 073412 (2008) [5] X. Li et al. Science 319, 1229 (2008)", "author_names": [ "Adam Rycerz" ], "corpus_id": 197678309, "doc_id": "197678309", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "7 cm GRAPHENE NANORIBBONS A KEY INGREDIENT FOR SOLID STATE QUANTUM INFORMATION PROCESSING", "venue": "", "year": 2008 }, { "abstract": "Submitted for the MAR11 Meeting of The American Physical Society Giant Spin Hall Effect and Nonlocal Transport in Graphene DMITRY ABANIN, Princeton, K.S. NOVOSELOV, A.K. GEIM, Manchester, L.S. LEVITOV, MIT Graphene provides a unique opportunity to explore quantumrelativistic phenomena in a condensed matter laboratory. Interesting phenomena associated with the parity anomaly, including quantum Hall effect in the absence of magnetic field and quantum spin Hall effect in quantizing magnetic fields, have been theoretically proposed, but could not be observed so far largely due to disorder and density inhonogeneity. We show that weak magnetic field induces large bulk non quantized spin Hall effect in graphene. The effect occurs due to Zeeman spin splitting which generates the imbalance of the Hall resistivities of the two spin species. The spin Hall effect is robust in the presence of disorder and interactions. It will manifest itself in large nonlocal transport mediated by long lived spin currents, as well as in spin injection and spin accumulation experiments. The effect peaks at the Dirac point, and can serve as a hallmark of the relativistic character of carriers in graphene and other Dirac materials. Dmitry Abanin Princeton Date submitted: 30 Dec 2010 Electronic form version 1.4", "author_names": [ "Dmitry A Abanin", "Kostya S Novoselov", "Andre K Geim", "Leonid S Levitov" ], "corpus_id": 118888284, "doc_id": "118888284", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Giant Spin Hall Effect and Nonlocal Transport in Graphene", "venue": "", "year": 2011 } ]

[ { "abstract": "Abstract The delamination in die attach layer is a problem that results in defects of semiconductor products. There are several elements and parameters, which are difficultly observed, causing delamination during the assembly process. Thus, it's critical to identify abnormal factors immediately for the real time correction and improvement. This paper proposes a two stage analysis framework to achieve two goals: identifying the key factors affecting delamination via variable selection and predicting the ratio of the delamination area in a die via the prediction models.", "author_names": [ "Shao-Yen Hung", "Yung-Lun Lin", "Chia-Yen Lee" ], "corpus_id": 139956293, "doc_id": "139956293", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Data Mining for Delamination Diagnosis in the Semiconductor Assembly Process", "venue": "", "year": 2017 }, { "abstract": "Increasingly, products with customized features are manufactured in small batches based on demand by unique customers. Such diversity leads to high product mix, thus severely impacting both production planning and scheduling activities such as frequent equipment setup and conversion. Despite increased complexity, production continues being pressured on minimal cycle time to meet on time delivery requirements. Focusing on the most challenging process, which is assembly, this paper presents batch sizing and lot splitting strategies to improve production cycle times. In the event of too short cycle time, overlapping technique is the most applicable, while \"parallel\" technique applies to normal cycle time. The commonly known \"batch queue\" technique works well for long cycle time such as new product qualification lot.", "author_names": [ "Zakiyah Zain", "Siti Mariam Man", "Mohd Kamal Mohd Nawawi" ], "corpus_id": 219662678, "doc_id": "219662678", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Batch Sizing and Lot Splitting Strategies to Reduce Cycle Time in Semiconductor Assembly Process", "venue": "", "year": 2020 }, { "abstract": "The transformation of wafers into chips is a complex manufacturing process involving literally thousands of equipment parameters. Delamination, a leading cause of defective products, can occur between die and epoxy molding compound (EMC) epoxy and substrate, lead frame and EMC, and so on. Troubleshooting is generally on a case by case basis and is both time consuming and labor intensive. We propose a three phase data science (DS) framework for process prognosis and prediction. The first phase is for data preprocessing. The second phase uses least absolute shrinkage and selection operator (LASSO) regression and stepwise regression to identify the key variables affecting delamination. The third phase develops a backpropagation neural network (BPNN) support vector regression (SVR) partial least squares (PLS) and gradient boosting machine (GBM) to predict the ratio of the delamination area in a die. We also investigate the imbalance between a false positive rate and a false negative rate after quality classification with BPN and GBM models to improve the tradeoff between the two types of risks. We conducted an empirical study of a semiconductor manufacturer, and the results show that the proposed framework provides an effective delamination prediction supporting the troubleshooting. In addition, for online prediction, it is necessary to determine the batch size for the timing of retraining the model, and we suggest the cost oriented method to solve the issue.", "author_names": [ "Shao-Yen Hung", "Chia-Yen Lee", "Yung-Lun Lin" ], "corpus_id": 211055578, "doc_id": "211055578", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Data Science for Delamination Prognosis and Online Batch Learning in Semiconductor Assembly Process", "venue": "IEEE Transactions on Components, Packaging and Manufacturing Technology", "year": 2020 }, { "abstract": "", "author_names": [ "Dong Zhao-hong", "Jang Bo-Kai", "Chia-Yen Lee" ], "corpus_id": 203116133, "doc_id": "203116133", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Equipment Health Monitoring in the Semiconductor Assembly Process.", "venue": "", "year": 2017 }, { "abstract": "Objectives: The purpose of this study was to evaluate the characteristics of worker exposure to hazardous chemical substances and propose the direction of work environment management for protecting worker's health in the semiconductor assembly process. Methods: Four assembly lines at two semiconductor manufacturing companies were selected for this study. We investigated the types of chemicals that were used and generated during the assembly process, and evaluated the workers' exposure levels to hazardous chemicals such as benzene and formaldehyde and the current work environment management in the semiconductor assembly process. Results: Most of the chemicals used at the assembly process are complex mixtures with high molecular weight such as adhesives and epoxy molding compounds(EMCs) These complex mixtures are stable when they are used at room temperature. However workers can be exposed to volatile organic compounds(VOCs) such as benzene and formaldehyde when they are used at high temperature over 100degC. The concentration levels of benzene and formaldehyde in chip molding process were higher than other processes. The reason was that by products were generated during the mold process due to thermal decomposition of EMC and machine cleaner at the process temperature(180degC) Conclusions: Most of the employees working at semiconductor assembly process are exposed directly or indirectly to various chemicals. Although the concentration levels are very lower than occupational exposure limits, workers can be exposed to carcinogens such as benzene and formaldehyde. Therefore, workers employed in the semiconductor assembly process should be informed of these exposure characteristics.", "author_names": [ "Seung-Hyun Park", "Hae Dong Park", "In Jae Shin" ], "corpus_id": 131407596, "doc_id": "131407596", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Exposure Characteristics for Chemical Substances and Work Environmental Management in the Semiconductor Assembly Process", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "" ], "corpus_id": 111508565, "doc_id": "111508565", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research of Yield Improvement for Semiconductor Assembly Process Using Equipment Trouble Prediction", "venue": "", "year": 2015 }, { "abstract": "", "author_names": [ "Muruhathasan Yogathasan" ], "corpus_id": 111615063, "doc_id": "111615063", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Simulation based analysis of cycle time and throughput in semiconductor assembly process integration", "venue": "", "year": 2002 }, { "abstract": "Ji Jian niDian Ya woYu etepurazumawoFa Sheng sase ruJian Ya Fang Dian Fang Shi to,Ta nogasuniBi beJue Yuan Po Huai Dian Ya gaDi ihe riumugasuwo Da Qi Ya Fang Dian saseruChang Ya Fang Dian Fang Shi gaa ru.Hou Zhe hahe riumu gasuwoDa Liang niShi Yong su rutame,ra nningukosu togaGao ku, Qian Zhe noJian Ya Fang Dian Fang Shi ga purazumaXi Jing noZhu Liu tona tsute i ru. Yi Ban ni,pu razumaXi Jing ha uetsu toXi Jing toBi be,Xia Ji no Te Chang gaagerare ru. (1) Wei Xi Gou Zao Wu niDui su ruXi Jing gaKe Neng dearu. (2) Huan Jing Fu He gaXiao sai. purazumaXi Jing haio nDeng noHe Dian Li Zi woYong iteXi Jing woXing u tame,Xi Jing Zhuang Zhi Nei Bu noDian Jie woZhi Yu shi,He Dian Li Zi niFang Xiang Xing woChi taseru kotode,Zhi Jing 1mmYi Xia noWei Xi Xue Nei Bu woXi Jing suru kotomoKe Neng dea ru.ma ta u etsu toXi Jing niBi be,Huan Jing De niWen Ti tona ruXi Jing Ye noDa Liang Shi Yong gaBu Yao tona ri,sa rani kosu toMian demoGao kosu tonaXi Jing Fei Ye Chu Li Zhuang Zhi wo,An Jia naPai gasuChu Li Zhuang Zhi niZhi kiHuan eru kotogade kiruDeng noLi Dian gaa ru. kore ranopurazumaXi Jing noTe Chang woHuo ka shitaYi Li toshite, Duo Ceng pu rin toHui Lu Ji Ban heno purazumaXi Jing noYing Yong Li woShao Jie su ru. reza Jia Gong biru doa tsuputai punoDuo Ceng pu rin toHui Lu Ji Ban nioite,Ceng Jian Dian Qi Dao Tong woDan ubaiahoru toHu ba re ruWei Xi Kong ha,Shu Zhi Jue Yuan Ceng niTan Suan gasu rezadeXue woKai keru kotodeXing Cheng sare ru.so noJi noShu Zhi noShao keCan rihasu mi a toHu bore,Ceng Jian Dian Qi Dao Tong woZu Hai su rutame,Xi Jing ni yotsu teQu riChu kanakerebana ranai.ko nosu miawoXi Jing Chu Qu su ruGong Cheng hadesu miatoHu bare,Cong Lai haGuo ma nganSuan noRong Ye deFen Jie Chu Qu su ruChu Li gaXing warete kita.shi ka shinaga ra, Jie Sok Bu noWei Xiao Hua niBan i,Chu Li Ye noXue henoJin Tou ga Kun Nan nina tsu teo ri,pu razu mani yorudesu miaChu Li gaCai Yong saretei ru.Tu 1ni purazumaXi Jing Chu Li Qian Hou noZou Cha Xian Wei Jing Guan Cha Xiang wo Shi su.pu razumani yorudesu miaChu Li haGuo ma nga nSuan Rong Ye woYong itaChu Li toYi na ri,You Hai naZhong Jin Shu Fei Ye woChu sazu, Wei Xiao naXue Cun Fa noXi Jing gaKe Neng tonaru. purazumaXi Jing haShang Shu no younaDuo kunoLi Dian woYou su ruga,", "author_names": [ "Hiroshi Haji", "Kiyoshi Kadoma Arita" ], "corpus_id": 100575297, "doc_id": "100575297", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Plasma Cleaning and Applications for Semiconductor Assembly Process", "venue": "", "year": 2000 }, { "abstract": "This paper considers a semiconductor assembly and test factory which is a three segment Constant Work in Process (CONWIP) system with overlapping machines. In the system, three types of carts circulate for meeting the physical requirements. The optimization problem in setting the suitable total Work in Process (WIP) level and the distribution in the three loops from the view of the trade off between the throughput and the WIP level for the system is addressed. In the proposed model, the system is firstly modeled as a three loop closed queue network and we propose an approximate method to evaluate the performance. The accuracy of the evaluation method was illustrated by numerical experiments, indicating that the method is fairly precise. Secondly, a Genetic Algorithm is designed to obtain near optimal results based on the performance evaluation. The semiconductor assembly and test system case as well as the application procedure were carried out in detail.", "author_names": [ "Na Li", "Shiqing Yao", "George Liu", "Caihua Zhuang" ], "corpus_id": 28248914, "doc_id": "28248914", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "Optimization of a multi Constant Work in Process semiconductor assembly and test factory based on performance evaluation", "venue": "Comput. Ind. Eng.", "year": 2010 }, { "abstract": "Hybrid nanoparticles have intrinsic advantages to achieve better activity in photocatalysis compared to single component materials, as it can synergistically combine functional components, which promote light absorption, charge transportation, surface reaction, and catalyst regeneration. Through functional modular assembly, a rational and stepwise approach has been developed to construct Fe3O4 CdS Au trimer nanoparticles and its derivatives as magnetically separable catalysts for photothermo catalytic hydrogen evolution from water. In a typical step by step synthetic process, Fe3O4 Ag dimers, Fe3O4 Ag2S dimers, Fe3O4 CdS dimers, and Fe3O4 CdS Au trimers were synthesized by seeding growth, sulfuration, ion exchange, and in situ reduction consequently. Following the same reaction route, a series of derivative trimer nanoparticles with alternative semiconductor and metal were obtained for water reduction reaction. The experimental results show that the semiconductor acts as an active component for photocatalysis, the metal nanoparticle acts as a cocatalyst for enhancement of charge separation, and the Fe3O4 component helps in the convenient separation of catalysts in magnetic field and improves photocatalytic activity under near infrared illumination due to photothermic effect.", "author_names": [ "Fei Pang", "Ruifang Zhang", "Dengpeng Lan", "Jianping Ge" ], "corpus_id": 206476807, "doc_id": "206476807", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Synthesis of Magnetite Semiconductor Metal Trimer Nanoparticles through Functional Modular Assembly: A Magnetically Separable Photocatalyst with Photothermic Enhancement for Water Reduction.", "venue": "ACS applied materials interfaces", "year": 2018 } ]

[ { "abstract": "\"Tea\" is a beverage which has a unique taste and aroma. The conventional method of tea manufacturing involves several stages. These are plucking, withering, rolling, fermentation, and finally firing. The quality parameters of tea (color, taste, and aroma) are developed during the fermentation stage where polyphenolic compounds are oxidized when exposed to air. Thus, controlling the fermentation stage will result in more consistent production of quality tea. The level of fermentation is often detected by humans as \"first\" and \"second\" noses as two distinct smell peaks appear during fermentation. The detection of the \"second\" aroma peak at the optimum fermentation is less consistent when decided by humans. Thus, an electronic nose is introduced to find the optimum level of fermentation detecting the variation in the aroma level. In this review, it is found that the systems developed are capable of detecting variation of the aroma level using an array of metal oxide semiconductor (MOS) gas sensors using different statistical and neural network techniques (SVD, 2 NM, MDM, PCA, SVM, RBF, SOM, PNN, and Recurrent Elman) successfully.", "author_names": [ "Tharaga Sharmilan", "Iresha Premarathne", "Indika Lasantha Wanniarachchi", "Sandya Kumari", "Dakshika Wanniarachchi" ], "corpus_id": 221903517, "doc_id": "221903517", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Electronic Nose Technologies in Monitoring Black Tea Manufacturing Process", "venue": "J. Sensors", "year": 2020 }, { "abstract": "Amino acids contribute to the nutritional value and quality of black tea. Fermentation is the most important stage of the black tea manufacturing process. In this study, we investigated protein degradation and proteinaceous amino acid metabolism associated with enzymatic reactions during fermentation in the black tea manufacturing process. The results showed that the concentrations of both protein and free amino acids decreased during fermentation. We also confirmed that proteins were broken down into free amino acids by artificially synthesized dipeptide benzyloxycarbonyl glutamyl tyrosine (Z Glu Tyr) Metabolites of the amino acid metabolic pathway increased significantly during fermentation. Furthermore, we confirmed that free amino acids were degraded to volatile compounds in a tracer experiment with the isotope precursor. These results provide information that will help black tea manufacturers improve the quality of black tea.", "author_names": [ "Yiyong Chen", "Lanting Zeng", "Yinyin Liao", "Jianlong Li", "Bo Zhou", "Ziyin Yang", "Jinchi Tang" ], "corpus_id": 210815456, "doc_id": "210815456", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Enzymatic Reaction Related Protein Degradation and Proteinaceous Amino Acid Metabolism during the Black Tea (Camellia sinensis) Manufacturing Process", "venue": "Foods", "year": 2020 }, { "abstract": "This study is focused on how the variation of physical parameters (temperature and humidity) in the factory will affect the fermentation stage of the black tea manufacturing process. Data for this paper was collected using an automated temperature and humidity monitoring device. Here, physical parameters for fermentation of dhool 1 tea particles were analyzed for 33 batches of samples (672 data) to find the best fit model for the bed tea leaves temperature. This temperature is directly related to the oxidation of polyphenolic compounds in tea. Monitoring device placed on the fermentation bed records ambient temperature, exhaust temperature, bed tea leaves temperature, ambient humidity, exhaust humidity with 3 minutes and 20 second intervals. Then these data were analyzed by correlation and regression analysis to find the best model for the bed tea leaves' temperature. According to the results obtained in the present investigation, bed tea leaves' temperature depends on actual time, exhaust temperature, exhaust humidity and ambient temperature. These can be considered as significant quality factors for determining the optimum bed tea leaves' temperature. The optimized best fit model explains about 75.34 percent of the variation in the response. For these data, the R2 value indicates the model provides an adequate fit to the data. Finally, these results highlight the importance of measuring tea bed exhaust temperature and humidity parameters rather an ambient condition for the black tea fermentation process.", "author_names": [ "S Tharaga", "B J Watawana", "W K I L Wanniarachchi", "K Sita Kumari", "Dakshika Wanniarachchi" ], "corpus_id": 208630115, "doc_id": "208630115", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Significance of Physical Parameters to Optimize the Bed Tea Leaves' Temperature During Fermentation Stage of Black Tea Manufacturing Process", "venue": "2018 IEEE International Conference on Information and Automation for Sustainability (ICIAfS)", "year": 2018 }, { "abstract": "Traceability practices and their compliances in low grown orthodox black tea manufacturing process were examined, while proposing possible solutions for identified major drawbacks. The physical traceability in supply chain was considered one step forward and one step backward from the point of manufacturing, starting from auction/buyer back to supplier. Randomized stratified sampling was used. The traceability was evaluated using a checklist, end product sampling, open ended interviews, observations and internal document studies. The orthodox process was more complicated unlike other production processes due to the different separation techniques employed for grading and variety of grades produced because the sifting/grading was the key to number of different tea varieties. Major traceability issues were observed in leaf collection and grading operations due to complexity of separation through Myddleton, Chota, Michie and Winnower, which reduced the specific amounts produced, where bulking and blending process further extended complexity, while increasing the mixing of different made tea together with increased number of suppliers. Considering 1st, 2nd, 3rd dhool and big bulk with given separation techniques during grading; a single tea leaf could pass many paths before it end up in a specific product due to weight, size and shape of the leaf of a shoot based on the way it was rolled in orthodox rollers, where traceability up to tea bush, grading, blending and traceability of sample back to supplier was not fully complying. Nevertheless, supplier records, traceability after packing, traceability at dispatch and after dispatch were in full compliance, and other factors had varying degree of traceability compliances which make the compliances unachievable. Alternatively, if made tea is considered as bulk material, use of emerging technologies like Radio Frequency Identification (RFID) tags or/and DNA barcoding may be potential tools in rectifying such drawbacks and further research is needed to assess their efficacy in the field.", "author_names": [ "Chandana Vindika Kumara Lokunarangodage", "Indira Wickramasinghe", "K K Ranaweera" ], "corpus_id": 56416966, "doc_id": "56416966", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Constraints and Compliances of Traceability in Low Grown Orthodox Black Tea Manufacturing Process", "venue": "", "year": 2015 }, { "abstract": "Abstract CTC (Crush, Tear and Curl) black tea, as one of the most representative black tea, is a very popular beverage in the world owing to its potential health benefits. However, the presence of toxic elements has gained more and more public health concerns. The contents of elements in tea were affected not only by growth environment but also by the technology of manufacturing process. Unfortunately, the studies of the influence of manufacturing process on the levels of elements in final tea products were very limited. In this study, the influence of manufacturing process on the levels of iron (Fe) copper (Cu) chromium (Cr) nickel (Ni) and manganese (Mn) in CTC black tea were determined by inductively coupled plasma mass spectrometry (ICP MS) It was found that the concentrations of Fe and Cu in tea leaves could greatly increase after rolling by rotorvane, which was proved to be the key stage affecting the Fe and Cu levels in final made tea. However, Cr and Ni contents in tea leaves increased greatly after cutting by CTC rollers. There was no significant difference among Mn concentrations in tea samples obtained from different stages according to the one way ANOVA analysis (p 0.05) The effect of brewing time and brewing times on the transfer rates were investigated. Ni displayed the highest transfer rate with the value of 75.74% while the transfer rates of Cu, Cr and Mn were 30.08% 26.62% and 34.98% respectively. With respect to the recommended daily allowance, the Fe, Cu, Cr and Ni in CTC black tea do not pose significant risk to human health while concerns should be paid to Mn since its HQ was still large than 1% even considering the bioavailability.", "author_names": [ "Lin Zhang", "Jianyang Zhang", "Liyan Chen", "Ting Liu", "Guicen Ma", "Xin Liu" ], "corpus_id": 89884629, "doc_id": "89884629", "n_citations": 14, "n_key_citations": 1, "score": 0, "title": "Influence of manufacturing process on the contents of iron, copper, chromium, nickel and manganese elements in Crush, Tear and Curl black tea, their transfer rates and health risk assessment", "venue": "", "year": 2018 }, { "abstract": "Abstract Instant tea powder is the fully soluble solid of tea that has emerged as a new and fast growing product in every country. The various processes involved in the commercial production of instant tea includeblending of tea leaves, hot water extraction, aroma recovery, soluble solids concentration, aroma restoration and dehydration. An envisaged process has been developed for the production of instant/soluble tea from the expressed juice of fermented tea leaves. Green tea leaves are subjected to withering, maceration, and fermentation process, which are similar to that of existing black tea production process. The fermented leaf is pressed to expel a part of juice containing soluble solids. The juice is then heated, centrifuged and vacuum dried to get soluble/instant tea powder. The pressed leaf residue is subjected to vacuum/hot air drying to obtain low grade conventional tea granules. About 20 2 g of soluble tea and 220 20 g of pressed cake tea are obtained from 1 kg of green tea leaves. The TF:TR ratio for soluble tea is 0.084 and that for pressed cake tea is 0.140. Industrial relevance The technology can be easily adopted by existing black tea manufacturers for simultaneous production of instant tea and black tea. The process is economical as both extracted juice and pressed cake are converted into value added products.", "author_names": [ "Chinta Someswararao", "Prem Prakash Srivastav" ], "corpus_id": 96050921, "doc_id": "96050921", "n_citations": 25, "n_key_citations": 1, "score": 0, "title": "A novel technology for production of instant tea powder from the existing black tea manufacturing process", "venue": "", "year": 2012 }, { "abstract": "Gasification of uprooted tea shrub (Camellia sinensis (L. O. Kuntze) is an attractive option for partial substitution of thermal energy in tea manufacturing industries. Chopped and dried uprooted tea branches with moisture content (X 20% have high energy contents suitable to generate process heat. Good number of tea processing units in Assam use old design and inefficient coal fired furnace and air heater with a low overall efficiency. Gasification of uprooted tea shrubs may be beneficial partially to substitute these old design coal fired furnaces. The calorific values of uprooted tea branches and generated producer gas were found 18.50 MJ kg 1 and 4.2 MJ m 3, yielded products at 65% cold gasification efficiency. Fermented tea samples with an average moisture content of 60% could be dried to 3% moisture using biomass gasifier and tea dryer setup. Simple economic analysis shows gasifier cum tea dryer technology may be economically favorable option with an annual saving of 21,067 in a medium scale tea factory (990 t per year made tea) if 28% of total thermal energy requirement is substituted by biomass gasification.", "author_names": [ "Partha Pratim Dutta", "Debendra Chandra Baruah" ], "corpus_id": 98604771, "doc_id": "98604771", "n_citations": 11, "n_key_citations": 2, "score": 0, "title": "Gasification of tea (Camellia sinensis (L. O. Kuntze) shrubs for black tea manufacturing process heat generation in Assam, India", "venue": "", "year": 2014 }, { "abstract": "As important biomolecules in Camellia sinensis L. lipids undergo substantial changes during black tea manufacture, which is considered to contribute to tea sensory quality. However, limited by analytical capacity, detailed lipid composition and its dynamic changes during black tea manufacture remain unclear. Herein, we performed tea lipidome profiling using high resolution liquid chromatography coupled to mass spectrometry (LC MS) which allows simultaneous and robust analysis of 192 individual lipid species in black tea, covering 17 (sub)classes. Furthermore, dynamic changes of tea lipids during black tea manufacture were investigated. Significant alterations of lipid pattern were revealed, involved with chlorophyll degradation, metabolic pathways of glycoglycerolipids, and other extraplastidial membrane lipids. To our knowledge, this report presented most comprehensive coverage of lipid species in black tea. This study provides a global and in depth metabolic map of tea lipidome during black tea manufacture.", "author_names": [ "Jia Li", "Jinjie Hua", "Qinghu Zhou", "Chun-wang Dong", "Jinjin Wang", "Yuliang Deng", "Haibo Yuan", "Yongwen Jiang" ], "corpus_id": 10110558, "doc_id": "10110558", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Comprehensive Lipidome Wide Profiling Reveals Dynamic Changes of Tea Lipids during Manufacturing Process of Black Tea.", "venue": "Journal of agricultural and food chemistry", "year": 2017 }, { "abstract": "Glycosides are known to be precursors of the alcoholic aroma compounds of black tea. They are hydrolyzed by endogenous glycosidases during the manufacturing process. Changes in the amounts of these glycosides during the manufacturing process were investigated by using a capillary gas chromatographic mass spectrometric analysis after trifluoroacetyl derivatization of the tea glycosidic fractions. Primeverosides were 3 fold more abundant than glucosides in fresh leaves, but they decreased greatly during the manufacturing process, especially during the stage of rolling. After the final stage of fermentation, primeverosides had almost disappeared, whereas glucosides were substantially unchanged. These results show that hydrolysis of the glycosides mainly occurred during the stage of rolling and confirm that primeverosides are the main black tea aroma precursors. This was also supported by the changes in the glycosidase activities in tea leaves. The glycosidase activities remained at a high level during withering but decreased drastically after rolling.", "author_names": [ "Dongmei Wang", "E Kurasawa", "Yuichi Yamaguchi", "Kikue Kubota", "Akio Kobayashi" ], "corpus_id": 196601376, "doc_id": "196601376", "n_citations": 58, "n_key_citations": 2, "score": 0, "title": "Analysis of glycosidically bound aroma precursors in tea leaves. 2. Changes in glycoside contents and glycosidase activities in tea leaves during the black tea manufacturing process.", "venue": "", "year": 2001 }, { "abstract": "Glycosides are known to be precursors of the alcoholic aroma compounds of black tea. They are hydrolyzed by endogenous glycosidases during the manufacturing process. Changes in the amounts of these glycosides during the manufacturing process were investigated by using a capillary gas chromatographic mass spectrometric analysis after trifluoroacetyl derivatization of the tea glycosidic fractions. Primeverosides were 3 fold more abundant than glucosides in fresh leaves, but they decreased greatly during the manufacturing process, especially during the stage of rolling. After the final stage of fermentation, primeverosides had almost disappeared, whereas glucosides were substantially unchanged. These results show that hydrolysis of the glycosides mainly occurred during the stage of rolling and confirm that primeverosides are the main black tea aroma precursors. This was also supported by the changes in the glycosidase activities in tea leaves. The glycosidase activities remained at a high level during withering but decreased drastically after rolling.", "author_names": [ "Donghai H Wang", "E Kurasawa", "Yuichi Yamaguchi", "Ken-ichi Kubota", "A Kobayashi" ], "corpus_id": 32060438, "doc_id": "32060438", "n_citations": 33, "n_key_citations": 2, "score": 0, "title": "Analysis of glycosidically bound aroma precursors in tea leaves. 2. Changes in glycoside contents and glycosidase activities in tea leaves during the black tea manufacturing process.", "venue": "Journal of agricultural and food chemistry", "year": 2001 } ]

[ { "abstract": "This study considers an actual real world problem encountered by ARM, the world's leading semiconductor intellectual property (IP) supplier, concerning the multi year assignment of weeks long computationally intensive projects (executable pieces of code) across a number of capacity limited clusters. The quality of a projects to cluster assignment is measured in terms of several metrics such as the even utilization of clusters, being able to realize all projects, and spreading projects of different research groups evenly across the clusters. The first (theoretical) contribution of this work is to motivate and formally define this novel application and put it in context with related literature. The second (experimental) contribution of this work is about gaining an understanding about the problem and performing an initial investigation on how different algorithm types (random search, an EMOA, and greedy search) fare on the problem. Our study revealed that the problem has many infeasible solutions and is challenging to optimize especially for long planning horizons (more than 3 years) While the EMOA is able to outperform random and greedy search (and also the current approach used at ARM) in terms of solution quality discovered, greedy search was the computationally most efficient approach and suitable for short term planning horizons (up to 1 year)", "author_names": [ "Silviu Tofan", "Richard W Allmendinger", "Manuela Zanda", "Olly Stephens" ], "corpus_id": 29030943, "doc_id": "29030943", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Heuristic allocation of computational resources", "venue": "GECCO", "year": 2017 }, { "abstract": "In this paper we survey computational models for Grid scheduling problems and their resolution using heuristic and meta heuristic approaches. Scheduling problems are at the heart of any Grid like computational system. Different types of scheduling based on different criteria, such as static versus dynamic environment, multi objectivity, adaptivity, etc. are identified. Then, heuristic and meta heuristic methods for scheduling in Grids are presented. The paper reveals the complexity of the scheduling problem in Computational Grids when compared to scheduling in classical parallel and distributed systems and shows the usefulness of heuristic and meta heuristic approaches for the design of efficient Grid schedulers. We also discuss on requirements for a modular Grid scheduling and its integration with Grid architecture.", "author_names": [ "Fatos Xhafa", "Ajith Abraham" ], "corpus_id": 5620912, "doc_id": "5620912", "n_citations": 371, "n_key_citations": 24, "score": 0, "title": "Computational models and heuristic methods for Grid scheduling problems", "venue": "Future Gener. Comput. Syst.", "year": 2010 }, { "abstract": "The paper studies the problem of finding an optimal subcarrier and power allocation strategy for downlink communication to multiple users in an orthogonal frequency division multiplexing based wireless system. The problem of minimizing total power consumption with constraints on bit error rate and transmission rate for users requiring different classes of service is formulated and simple algorithms with good performance are derived. The problem of joint allocation is divided into two steps. In the first step, the number of subcarriers that each user gets is determined based on the users' average signal to noise ratio. The algorithm is shown to find the distribution of subcarriers that minimizes the total power required when every user experiences a flat fading channel. In the second stage of the algorithm, it finds the best assignment of subcarriers to users. Two different approaches are presented, the rate craving greedy algorithm and the amplitude craving greedy algorithm. A single cell with one base station and many mobile stations is considered. Numerical results demonstrate that the proposed low complexity algorithms offer comparable performance with an existing iterative algorithm.", "author_names": [ "Didem Kivanc-Tureli", "Guoqing Li", "Hui Liu" ], "corpus_id": 12598394, "doc_id": "12598394", "n_citations": 707, "n_key_citations": 51, "score": 0, "title": "Computationally efficient bandwidth allocation and power control for OFDMA", "venue": "IEEE Trans. Wirel. Commun.", "year": 2003 }, { "abstract": "Invention is here interpreted broadly as the production of knowledge. From the viewpoint of welfare economics, the determination of optimal resource allocation for invention will depend on the technological characteristics of the invention process and the nature of the market for knowledge.", "author_names": [ "Kenneth J Arrow" ], "corpus_id": 38456056, "doc_id": "38456056", "n_citations": 8747, "n_key_citations": 812, "score": 0, "title": "Economic Welfare and the Allocation of Resources for Invention", "venue": "", "year": 1962 }, { "abstract": "The usefulness of Lagrange multipliers for optimization in the presence of constraints is not limited to differentiable functions. They can be applied to problems of maximizing an arbitrary real valued objective function over any set whatever, subject to bounds on the values of any other finite collection of real valued functions denned on the same set. While the use of the Lagrange multipliers does not guarantee that a solution will necessarily be found for all problems, it is \"fail safe\" in the sense that any solution found by their use is a true solution. Since the method is so simple compared to other available methods it is often worth trying first, and succeeds in a surprising fraction of cases. They are particularly well suited to the solution of problems of allocating limited resources among a set of independent activities.", "author_names": [ "Harvey J Everett" ], "corpus_id": 122381976, "doc_id": "122381976", "n_citations": 1271, "n_key_citations": 43, "score": 0, "title": "Generalized Lagrange Multiplier Method for Solving Problems of Optimum Allocation of Resources", "venue": "", "year": 1963 }, { "abstract": "Abstract We apply the two player game assumptions of limited search horizon and commitment to moves in constant time, to single agent heuristic search problems. We present a variation of minimax lookahead search, and an analog to alpha beta pruning that significantly improves the efficiency of the algorithm. Paradoxically, the search horizon reachable with this algorithm increases with increasing branching factor. In addition, we present a new algorithm, called Real Time A* for interleaving planning and execution. We prove that the algorithm makes locally optimal decisions and is guaranteed to find a solution. We also present a learning version of this algorithm that improves its performance over successive problem solving trials by learning more accurate heuristic values, and prove that the learned values converge to their exact values along every optimal path. These algorithms effectively solve significantly larger problems than have previously been solvable using heuristic evaluation functions.", "author_names": [ "Richard E Korf" ], "corpus_id": 11749385, "doc_id": "11749385", "n_citations": 1043, "n_key_citations": 134, "score": 0, "title": "Real Time Heuristic Search", "venue": "Artif. Intell.", "year": 1990 }, { "abstract": "In the AIPS98 Planning Contest, the HSP planner showed that heuristic search planners can be competitive with state of the art Graphplan and SAT planners. Heuristic search planners like HSP transform planning problems into problems of heuristic search by automatically extracting heuristics from Strips encodings. They differ from specialized problem solvers such as those developed for the 24 Puzzle and Rubik's Cube in that they use a general declarative language for stating problems and a general mechanism for extracting heuristics from these representations. In this paper, we study a family of heuristic search planners that are based on a simple and general heuristic that assumes that action preconditions are independent. The heuristic is then used in the context of best first and hill climbing search algorithms, and is tested over a large collection of domains. We then consider variations and extensions such as reversing the direction of the search for speeding node evaluation, and extracting information about propositional invariants for avoiding dead ends. We analyze the resulting planners, evaluate their performance, and explain when they do best. We also compare the performance of these planners with two state of the art planners, and show that the simplest planner based on a pure best first search yields the most solid performance over a large set of problems. We also discuss the strengths and limitations of this approach, establish a correspondence between heuristic search planning and Graphplan, and briefly survey recent ideas that can reduce the current gap in performance between general heuristic search planners and specialized solvers. 2001 Elsevier Science B.V. All rights reserved.", "author_names": [ "Blai Bonet", "Hector Geffner" ], "corpus_id": 11337237, "doc_id": "11337237", "n_citations": 1018, "n_key_citations": 105, "score": 0, "title": "Planning as heuristic search", "venue": "Artif. Intell.", "year": 2001 }, { "abstract": "As reflected in the amount of controversy, few areas in psychology have undergone such dramatic conceptual changes in the past decade as the emerging science of heuristics. Heuristics are efficient cognitive processes, conscious or unconscious, that ignore part of the information. Because using heuristics saves effort, the classical view has been that heuristic decisions imply greater errors than do \"rational\" decisions as defined by logic or statistical models. However, for many decisions, the assumptions of rational models are not met, and it is an empirical rather than an a priori issue how well cognitive heuristics function in an uncertain world. To answer both the descriptive question \"Which heuristics do people use in which situations?\" and the prescriptive question \"When should people rely on a given heuristic rather than a complex strategy to make better judgments?\" formal models are indispensable. We review research that tests formal models of heuristic inference, including in business organizations, health care, and legal institutions. This research indicates that (a) individuals and organizations often rely on simple heuristics in an adaptive way, and (b) ignoring part of the information can lead to more accurate judgments than weighting and adding all information, for instance for low predictability and small samples. The big future challenge is to develop a systematic theory of the building blocks of heuristics as well as the core capacities and environmental structures these exploit.", "author_names": [ "Gerd Gigerenzer", "Wolfgang Gaissmaier" ], "corpus_id": 8402936, "doc_id": "8402936", "n_citations": 2232, "n_key_citations": 100, "score": 0, "title": "Heuristic decision making.", "venue": "Annual review of psychology", "year": 2011 }, { "abstract": "This paper introduces a theoretical framework that describes the importance of affect in guiding judgments and decisions. As used here, 'affect' means the specific quality of 'goodness' or 'badness' (i) experienced as a feeling state (with or without consciousness) and (ii) demarcating a positive or negative quality of a stimulus. Affective responses occur rapidly and automatically note how quickly you sense the feelings associated with the stimulus word 'treasure' or the word 'hate' We argue that reliance on such feelings can be characterized as 'the affect heuristic' In this paper we trace the development of the affect heuristic across a variety of research paths followed by ourselves and many others. We also discuss some of the important practical implications resulting from ways that this heuristic impacts our daily lives. 2002 Cambridge University Press. Published by Elsevier B.V.", "author_names": [ "Paul Slovic", "Melissa L Finucane", "Ellen Peters", "Donald G MacGregor" ], "corpus_id": 1941040, "doc_id": "1941040", "n_citations": 1681, "n_key_citations": 99, "score": 0, "title": "The affect heuristic", "venue": "Eur. J. Oper. Res.", "year": 2007 }, { "abstract": "Abstract This paper describes an implementation of the Lin Kernighan heuristic, one of the most successful methods for generating optimal or near optimal solutions for the symmetric traveling salesman problem (TSP) Computational tests show that the implementation is highly effective. It has found optimal solutions for all solved problem instances we have been able to obtain, including a 13,509 city problem (the largest non trivial problem instance solved to optimality today)", "author_names": [ "Keld Helsgaun" ], "corpus_id": 14802229, "doc_id": "14802229", "n_citations": 1302, "n_key_citations": 165, "score": 0, "title": "An effective implementation of the Lin Kernighan traveling salesman heuristic", "venue": "Eur. J. Oper. Res.", "year": 2000 } ]

[ { "abstract": "It is very hard to realize a 6 bit resolution millimeter wave phase shifter whether by passive structure or by active structure. A 52 57 GHz 6 bit phase shifter with hybrid of passive and active structures is proposed. The switched LC phase shifter is adopted for the passive structure because of its compact size, and the vector sum phase shifter is chosen for the active structure in the 6 bit phase shifter. The proposed 6 bit phase shifter uses the passive structure to realize 5.625deg and 11.25deg phase shifts and uses the active structure to realize the <inline formula> <tex math notation=\"LaTeX\"$N \\times 22.5^\\circ /tex math>/inline formula> phase shifts. Implemented in Taiwan Semiconductor Manufacturing Company 40 nm CMOS technology, the 6 bit phase shifter has a RMS error <3.76deg and a RMS gain error <2.23 dB at 52 57 GHz. The proposed 6 bit millimeter wave phase shifter achieves a high phase resolution with a compact size. The core die occupies an area of 500 <inline formula> <tex math notation=\"LaTeX\"\\mu \\text{m}\\times 300\\\\mu \\text{m} /tex math>/inline formula> and consumes about 13 mA from a 1.1 V supply.", "author_names": [ "Xing Quan", "Xiang Yi", "Chirn Chye Boon", "Kaituo Yang", "Chenyang Li", "Bei Liu", "Zhipeng Liang", "Yiqi Zhuang" ], "corpus_id": 3879555, "doc_id": "3879555", "n_citations": 21, "n_key_citations": 0, "score": 1, "title": "A 52 57 GHz 6 Bit Phase Shifter With Hybrid of Passive and Active Structures", "venue": "IEEE Microwave and Wireless Components Letters", "year": 2018 }, { "abstract": "Differential phase shift keying (DPSK) has recently been used to reach record distances in long haul lightwave communication systems. This paper will review theoretical, as well as implementation, aspects of DPSK, and discuss experimental results.", "author_names": [ "Alan H Gnauck", "Peter J Winzer" ], "corpus_id": 36817072, "doc_id": "36817072", "n_citations": 914, "n_key_citations": 70, "score": 0, "title": "Optical phase shift keyed transmission", "venue": "Journal of Lightwave Technology", "year": 2005 }, { "abstract": "Multiuser orthogonal frequency division multiplexing (OFDM) with adaptive multiuser subcarrier allocation and adaptive modulation is considered. Assuming knowledge of the instantaneous channel gains for all users, we propose a multiuser OFDM subcarrier, bit, and power allocation algorithm to minimize the total transmit power. This is done by assigning each user a set of subcarriers and by determining the number of bits and the transmit power level for each subcarrier. We obtain the performance of our proposed algorithm in a multiuser frequency selective fading environment for various time delay spread values and various numbers of users. The results show that our proposed algorithm outperforms multiuser OFDM systems with static time division multiple access (TDMA) or frequency division multiple access (FDMA) techniques which employ fixed and predetermined time slot or subcarrier allocation schemes. We have also quantified the improvement in terms of the overall required transmit power, the bit error rate (BER) or the area of coverage for a given outage probability.", "author_names": [ "Cheong Yui Wong", "Roger S Cheng", "Khaled Ben Letaief", "Ross D Murch" ], "corpus_id": 7620348, "doc_id": "7620348", "n_citations": 2825, "n_key_citations": 173, "score": 0, "title": "Multiuser OFDM with adaptive subcarrier, bit, and power allocation", "venue": "IEEE J. Sel. Areas Commun.", "year": 1999 }, { "abstract": "This paper presents a low power 10 bit 50 MS/s successive approximation register (SAR) analog to digital converter (ADC) that uses a monotonic capacitor switching procedure. Compared to converters that use the conventional procedure, the average switching energy and total capacitance are reduced by about 81% and 50% respectively. In the switching procedure, the input common mode voltage gradually converges to ground. An improved comparator diminishes the signal dependent offset caused by the input common mode voltage variation. The prototype was fabricated using 0.13 ?m 1P8M CMOS technology. At a 1.2 V supply and 50 MS/s, the ADC achieves an SNDR of 57.0 dB and consumes 0.826 mW, resulting in a figure of merit (FOM) of 29 fJ/conversion step. The ADC core occupies an active area of only 195 x 265 ?m2.", "author_names": [ "Chun-Cheng Liu", "Soon-Jyh Chang", "Guan-Ying Huang", "Ying-Zu Lin" ], "corpus_id": 7206993, "doc_id": "7206993", "n_citations": 870, "n_key_citations": 104, "score": 0, "title": "A 10 bit 50 MS/s SAR ADC With a Monotonic Capacitor Switching Procedure", "venue": "IEEE Journal of Solid State Circuits", "year": 2010 }, { "abstract": "Integrated 60 GHz active and passive phase shifters for RF path phase shifting phased array transceivers are demonstrated in this paper. The reflection type passive phase shifter achieves 180deg phase variation across the 57GHz 64GHz band with insertion loss varying from 4.2dB 7.5dB at 60GHz. The active phase shifter employs vector interpolation architecture and achieves 360deg phase variation, 2dB gain, 12GHz 3dB bandwidth and 16.5dB noise figure at 60GHz. Measurements over process and temperature are also discussed and comparisons are drawn between active and passive phase shifting approach for 60GHz phased arrays.", "author_names": [ "Ming-Da Tsai", "Arun S Natarajan" ], "corpus_id": 14132419, "doc_id": "14132419", "n_citations": 89, "n_key_citations": 6, "score": 0, "title": "60GHz passive and active RF path phase shifters in silicon", "venue": "2009 IEEE Radio Frequency Integrated Circuits Symposium", "year": 2009 }, { "abstract": "This paper presents our vision of Human Computer Interaction (HCI) \"Tangible Bits.\" Tangible Bits allows users to \"grasp manipulate\" bits in the center of users' attention by coupling the bits with everyday physical objects and architectural surfaces. Tangible Bits also enables users to be aware of background bits at the periphery of human perception using ambient display media such as light, sound, airflow, and water movement in an augmented space. The goal of Tangible Bits is to bridge the gaps between both cyberspace and the physical environment, as well as the foreground and background of human activities. This paper describes three key concepts of Tangible Bits: interactive surfaces; the coupling of bits with graspable physical objects; and ambient media for background awareness. We illustrate these concepts with three prototype systems the metaDESK, transBOARD and ambientROOM to identify underlying research issues.", "author_names": [ "Hiroshi Ishii", "Brygg Ullmer" ], "corpus_id": 462228, "doc_id": "462228", "n_citations": 4077, "n_key_citations": 208, "score": 0, "title": "Tangible bits: towards seamless interfaces between people, bits and atoms", "venue": "CHI", "year": 1997 }, { "abstract": "Based on the indoor radio wave propagation analysis, and the fundamental limits of CMOS technology it is shown that phased array technology is the ultimate solution for the radio and physical layer of the millimeter wave multi Gb/s wireless networks. A low cost, single receiver array architecture with RF phase shifting is proposed and design, analysis and measurements of its key components are presented. A high gain, two stage, low noise amplifier in 90 nm CMOS technology with more than 20 dB gain over the 60 GHz spectrum is designed. Furthermore, a broadband analog phase shifter with a linear phase and low insertion loss variation is designed, and its measured characteristics are presented. Moreover, two novel beamforming techniques for millimeter wave phased array receivers are developed in this paper. The performance of these methods for line of sight and multipath signal propagation conditions is studied. It is shown that one of the proposed beamforming methods has an excess gain of up to 14 dB when the line of sight link is obstructed by a human.", "author_names": [ "Mohammad Fakharzadeh", "Mohammad-Reza Nezhad-Ahmadi", "Behzad Biglarbegian", "Javad J Ahmadi-Shokouh", "Safieddin Safavi-Naeini" ], "corpus_id": 27482004, "doc_id": "27482004", "n_citations": 81, "n_key_citations": 1, "score": 0, "title": "CMOS Phased Array Transceiver Technology for 60 GHz Wireless Applications", "venue": "IEEE Transactions on Antennas and Propagation", "year": 2010 }, { "abstract": "This thesis evaluates bit rate selection techniques to maximize throughput over wireless links that are capable of multiple bit rates. The key challenges in bit rate selection are determining which bit rate provides the most throughput and knowing when to switch to another bit rate that would provide more throughput. This thesis presents the SampleRate bit rate selection algorithm. SampleRate sends most data packets at the bit rate it believes will provide the highest throughput. SampleRate periodically sends a data packet at some other bit rate in order to update a record of that bit rate's loss rate. SampleRate switches to a different bit rate if the throughput estimate based on the other bit rate's recorded loss rate is higher than the current bit rate's throughput. Measuring the loss rate of each supported bit rate would be inefficient because sending packets at lower bit rates could waste transmission time, and because successive unicast losses are time consuming for bit rates that do not work. SampleRate addresses this problem by only sampling at bit rates whose lossless throughput is better than the current bit rate's throughput. SampleRate also stops probing at a bit rate if it experiences several successive losses. This thesis presents measurements from indoor and outdoor wireless networks that demonstrate that SampleRate performs as well or better than other bit rate selection algorithms. SampleRate performs better than other algorithms on links where all bit rates suffer from significant loss. Thesis Supervisor: Robert T. Morris Title: Assistant Professor of Computer Science and Engineering", "author_names": [ "John C Bicket" ], "corpus_id": 111286952, "doc_id": "111286952", "n_citations": 628, "n_key_citations": 118, "score": 0, "title": "Bit rate selection in wireless networks", "venue": "", "year": 2005 }, { "abstract": "A 5 bit digital controlled switch type passive phase shifter realised in a 40 nm digital CMOS technology without ultra thick metals for the 60 GHz Industrial, Scientific and Medical (ISM) band is presented. A patterned shielding with electromagnetic bandgap structure and a stacked metals method to increase the on chip inductor quality factor are proposed. To reduce the insertion loss from the transistors, the transistor switches are implemented with a body source connection. For all 32 states, the minimum phase error is 1.5deg, and the maximum phase error is 6.8deg. The measured insertion loss is 20.9 1 dB including pad loss at 60 GHz and the return loss is >10 dB over 57 64 GHz. The total chip size is 0.24 mm2 with 0 mW DC power consumption.", "author_names": [ "Hao Gao", "Kuangyuan Ying", "Marion K Matters-Kammerer", "Pja Pieter Harpe", "Bindi Wang", "B Bo Liu", "Wouter A Serdijn", "Pgm Peter Baltus" ], "corpus_id": 4646273, "doc_id": "4646273", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "60 GHz 5 bit digital controlled phase shifter in a digital 40 nm CMOS technology without ultra thick metals", "venue": "", "year": 2016 }, { "abstract": "With the severe spectrum shortage in conventional cellular bands, large scale antenna systems in the mmWave bands can potentially help to meet the anticipated demands of mobile traffic in the 5G era. There are many challenging issues, however, regarding the implementation of digital beamforming in large scale antenna systems: complexity, energy consumption, and cost. In a practical large scale antenna deployment, hybrid analog and digital beamforming structures can be important alternative choices. In this article, optimal designs of hybrid beamforming structures are investigated, with the focus on an N (the number of transceivers) by M (the number of active antennas per transceiver) hybrid beamforming structure. Optimal analog and digital beamforming designs in a multi user beamforming scenario are discussed. Also, the energy efficiency and spectrum efficiency of the N x M beamforming structure are analyzed, including their relationship at the green point (i.e. the point with the highest energy efficiency) on the energy efficiency spectrum efficiency curve, the impact of N on the energy efficiency performance at a given spectrum efficiency value, and the impact of N on the green point energy efficiency. These results can be conveniently utilized to guide practical LSAS design for optimal energy/ spectrum efficiency trade off. Finally, a reference signal design for the hybrid beamform structure is presented, which achieves better channel estimation performance than the method solely based on analog beamforming. It is expected that large scale antenna systems with hybrid beamforming structures in the mmWave band can play an important role in 5G.", "author_names": [ "Shuangfeng Han", "I Chih-Lin", "Zhikun Xu", "Corbett Rowell" ], "corpus_id": 13073284, "doc_id": "13073284", "n_citations": 819, "n_key_citations": 38, "score": 0, "title": "Large scale antenna systems with hybrid analog and digital beamforming for millimeter wave 5G", "venue": "IEEE Communications Magazine", "year": 2015 } ]

[ { "abstract": "Colloidal core/shell nanocrystals contain at least two semiconductor materials in an onionlike structure. The possibility to tune the basic optical properties of the core nanocrystals, for example, their fluorescence wavelength, quantum yield, and lifetime, by growing an epitaxial type shell of another semiconductor has fueled significant progress on the chemical synthesis of these systems. In such core/shell nanocrystals, the shell provides a physical barrier between the optically active core and the surrounding medium, thus making the nanocrystals less sensitive to environmental changes, surface chemistry, and photo oxidation. The shell further provides an efficient passivation of the surface trap states, giving rise to a strongly enhanced fluorescence quantum yield. This effect is a fundamental prerequisite for the use of nanocrystals in applications such as biological labeling and light emitting devices, which rely on their emission properties. Focusing on recent advances, this Review discusses the fundamental properties and synthesis methods of core/shell and core/multiple shell structures of II VI, IV VI, and III V semiconductors.", "author_names": [ "Peter Reiss", "Myriam Protiere", "Liang Li" ], "corpus_id": 9428365, "doc_id": "9428365", "n_citations": 1524, "n_key_citations": 23, "score": 1, "title": "Core/Shell semiconductor nanocrystals.", "venue": "Small", "year": 2009 }, { "abstract": "A strong electron hole exchange interaction (EI) in semiconductor nanocrystals (NCs) gives rise to a large (up to tens of meV) splitting between optically active 'bright' and optically passive 'dark' excitons. This dark bright splitting has a significant effect on the optical properties of band edge excitons and leads to a pronounced temperature and magnetic field dependence of radiative decay. Here we demonstrate a nanoengineering based approach that provides control over EI while maintaining nearly constant emission energy. We show that the dark bright splitting can be widely tuned by controlling the electron hole spatial overlap in core shell CdSe/CdS NCs with a variable shell width. In thick shell samples, the EI energy reduces to <250 meV, which yields a material that emits with a nearly constant rate over temperatures from 1.5 to 300 K and magnetic fields up to 7 T. The EI manipulation strategies demonstrated here are general and can be applied to other nanostructures with variable electron hole overlap.", "author_names": [ "Sergio Brovelli", "Richard D Schaller", "Scott A Crooker", "Florencio Garcia-Santamaria", "Yuan Chen", "Ranjani Viswanatha", "Jennifer Ann Hollingsworth", "Han Htoon", "Victor I Klimov" ], "corpus_id": 10986680, "doc_id": "10986680", "n_citations": 219, "n_key_citations": 4, "score": 0, "title": "Nano engineered electron hole exchange interaction controls exciton dynamics in core shell semiconductor nanocrystals", "venue": "Nature communications", "year": 2011 }, { "abstract": "A theoretical study of the positive and negative trion channels in the nonradiative Auger recombination of band edge biexcitons (BXs) in CdSe/CdS core/shell nanocrystals (NCs) is presented. The theory takes into account the BX fine structure produced by NC asymmetry and hole hole exchange interaction. The calculations show that growth of CdS shell upon CdSe core suppresses the rate of the Auger recombination via negative trion channel, while the more efficient Auger recombination via positive trion channel shows much weaker dependence on the shell thickness. The demonstrated oscillatory dependence of the BX Auger rate on the core and shell sizes is explained qualitatively in terms of overlap of the ground and excited carrier wave functions. The calculations show that raise of temperature accelerates the Auger recombination in CdSe/CdS NCs due to reduction of the bulk energy gaps of CdSe and CdS.", "author_names": [ "Roman Vaxenburg", "Anna V Rodina", "Efrat Lifshitz", "Alexander L Efros" ], "corpus_id": 40692414, "doc_id": "40692414", "n_citations": 48, "n_key_citations": 0, "score": 0, "title": "Biexciton Auger Recombination in CdSe/CdS Core/Shell Semiconductor Nanocrystals.", "venue": "Nano letters", "year": 2016 }, { "abstract": "Concomitant with the development of polymer nanocomposite (PNC) technologies across numerous industries is an expanding awareness of the uncertainty with which engineered nanoparticles embedded within these materials may be released into the external environment, particularly liquid media. Recently there has been an interest in evaluating potential exposure to nanoscale fillers from PNCs, but existing studies often rely upon uncharacterized, poor quality, or proprietary materials, creating a barrier to making general mechanistic conclusions about release phenomena. In this study we employed semiconductor nanoparticles (quantum dots, QDs) as model nanofillers to quantify potential release into liquid media under specific environmental conditions. QDs of two sizes were incorporated into low density polyethylene by melt compounding and the mixtures were extruded as free standing fluorescent films. These films were subjected to tests under conditions intended to accelerate potential release of embedded particles or dissolved residuals into liquid environments. Using inductively coupled plasma mass spectrometry and laser scanning confocal microscopy, it was found that the acidity of the external medium, exposure time, and small differences in particle size (on the order of a few nm) all play pivotal roles in release kinetics. Particle dissolution was found to play a major if not dominant role in the release process. This paper also presents the first evidence that internally embedded nanoparticles contribute to the mass transfer, an observation made possible via the use of a model system that was deliberately designed to probe the complex relationships between nanoparticle enabled plastics and the environment.", "author_names": [ "K Venkatanarasimha Pillai", "Patrick Gray", "C C Tien", "Reiner Bleher", "Li Piin Sung", "Timothy V Duncan" ], "corpus_id": 23786755, "doc_id": "23786755", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Environmental release of core shell semiconductor nanocrystals from free standing polymer nanocomposite films.", "venue": "Environmental science. Nano", "year": 2016 }, { "abstract": "The present study investigates the photocatalytic activity of ZnSe/CdS core/shell semiconductor nanocrystals. These nanoparticles exhibit a spatial separation of photoinduced charges between the core and the shell domains, which makes them potentially viable for photocatalytic applications. Unfortunately, one of the excited charges remains inside the core semiconductor and thus cannot efficiently react with the external environment. Here, we explore this issue by investigating the mechanisms of hole extraction from the ZnSe core to the surface of the CdS shell. In particular, the effect of shell thickness in ZnSe/CdS core/shell nanocrystals on the ability of core localized charges to perform oxidative reactions was determined. By using a combination of time resolved spectroscopy and electrochemical techniques, we demonstrate that the use of hole scavenging surfactants facilitates an efficient transfer of core localized holes to the surface even in the case of shells exceeding 7 nm in thickness. These meas.", "author_names": [ "Dimuthu Perera", "Ryan Lorek", "Rony S Khnayzer", "Pavel Moroz", "Timothy F O'Connor", "Dmitry Khon", "Geoffrey M Diederich", "Erich W Kinder", "Scott Lambright", "Felix N Castellano", "Mikhail Zamkov" ], "corpus_id": 54655170, "doc_id": "54655170", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Photocatalytic Activity Of Core/shell Semiconductor Nanocrystals Featuring Spatial Separation Of Charges", "venue": "", "year": 2012 }, { "abstract": "Quantum dots are semiconducting nanocrystals that exhibit extraordinary optical properties. QD have shown higher photostability compared to standard organic dye type probes. Therefore, they have been heavily explored in the biomedical field. This review will discuss the different approaches to synthesis, solubilise and functionalise QD. Their main biomedical applications in imaging and photodynamic therapy will be highlighted. Finally, QD biodistribution profile and in vivo toxicity will be discussed.", "author_names": [ "Wafa' T Al-Jamal" ], "corpus_id": 3601535, "doc_id": "3601535", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Core shell Semiconductor Nanocrystals: Effect of Composition, Size, Surface Coatings on their Optical Properties, Toxicity and Pharmacokinetics.", "venue": "Current pharmaceutical design", "year": 2017 }, { "abstract": "We report the synthesis of spherical ZnTe nanocrystals and the successive coating with a ZnS shell to afford core/shell quantum dots. These nanocrystals can represent alternatives to cadmium based quantum dots but their preparation and properties are challenging and relatively unexplored. The effect of various synthetic parameters on the reaction outcome was investigated, and the resulting nanocrystals were characterized by TEM, EDX, XPS, and spectroscopic measurements. The optical data indicate that these core/shell quantum dots belong to type I, i.e. both the electron and the hole are confined within the ZnTe core. Both the ZnTe core and ZnTe/ZnS core/shell quantum dot samples absorb in the visible region and are not luminescent. The ZnS shell preserves the optical properties of the core and improves the chemical and photochemical stability of the nanoparticles in air equilibrated solution, whereas they appear to be quite fragile in the solid state. XPS results have evidenced the distinct nature of core and core/shell QDs, confirming the formation of QDs with shells of different thicknesses and their evolution due to oxidation upon air exposure. Anodic photocurrent generation was observed when an ITO electrode functionalized with ZnTe/ZnS nanocrystals was irradiated in the visible region in a photoelectrochemical cell, indicating that the quantum dots perform spectral sensitization of the electron injection into the ITO electrode. Conversely, cathodic photocurrent generation was not observed; hence, the QD modified electrode performs electrical rectification under a photon energy input.", "author_names": [ "Christophe Lincheneau", "Matteo Amelia", "Marek F Oszajca", "Alice Boccia", "Fabio D'Orazi", "Mattia Madrigale", "Robertino Zanoni", "Raffaello Mazzaro", "Luca Ortolani", "Vittorio Morandi", "Serena Silvi", "Konrad Szacilowski", "Alberto Credi" ], "corpus_id": 136692362, "doc_id": "136692362", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Synthesis and properties of ZnTe and ZnTe/ZnS core/shell semiconductor nanocrystals", "venue": "", "year": 2014 }, { "abstract": "We conducted a comparative synthesis of water soluble CdTe/CdS colloidal nanocrystalline semiconductors of the core/shell type. We prepared the CdS shell using two different methods: a one pot approach and successive ionic layer adsorption and reaction (SILAR) in both cases, we used 3 mercaptopropionic acid (MPA) as the surface ligand. In the one pot approach, thiourea was added over the freshly formed CdTe dispersion, and served as the sulfur source. We achieved thicker CdS layers by altering the Cd:S stoichiometric ratio (1:1, 1:2, 1:4, and 1:8) The Cd:S ratios 1:1 and 1:2 furnished the best optical properties; these ratios also made the formation of surface defects less likely. For CdTe/CdS obtained using SILAR, we coated the surface of three differently sized CdTe cores (2.17, 3.10, and 3.45 nm) with one to five CdS layers using successive injections of the Cd2+ and S2 ions. The results showed that the core size influenced the optical properties of the materials. The deposition of three to five layers over the surface of smaller CdTe colloidal nanocrystals generated strain effects on the core/shell structure.", "author_names": [ "Brener R C Vale", "Fernanda O Silva", "Melissa da Silva Carvalho", "Ellen Raphael", "Jefferson Luiz Ferrari", "Marco Antonio Schiavon" ], "corpus_id": 44024848, "doc_id": "44024848", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Water Soluble CdTe/CdS Core/Shell Semiconductor Nanocrystals: How Their Optical Properties Depend on the Synthesis Methods", "venue": "", "year": 2016 }, { "abstract": "Semiconductor nanocrystals of different formulations have been extensively studied for use in thin film photovoltaics. Materials used in such devices need to satisfy the stringent requirement of having large absorption cross sections. Hence, type II semiconductor nanocrystals that are generally considered to be poor light absorbers have largely been ignored. In this article, we show that type II semiconductor nanocrystals can be tailored to match the light absorption abilities of other types of nanostructures as well as bulk semiconductors. We synthesize type II ZnTe/CdS core/shell nanocrystals. This material is found to exhibit a tunable band gap as well as absorption cross sections that are comparable to CdTe. This result has significant implications for thin film photovoltaics, where the use of type II nanocrystals instead of pure semiconductors can improve charge separation while also providing a much needed handle to regulate device composition.", "author_names": [ "Rekha Mahadevu", "Aniruddha R Yelameli", "Bharati Panigrahy", "Anshu Pandey" ], "corpus_id": 2277350, "doc_id": "2277350", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Controlling light absorption in charge separating core/shell semiconductor nanocrystals.", "venue": "ACS nano", "year": 2013 }, { "abstract": "Summary In this study, we report on CdS/ZnS nanocrystals as a luminescence probe for bioimaging applications. CdS nanocrystals capped with a ZnS shell had enhanced luminescence intensity, stronger stability and exhibited a longer lifetime compared to uncapped CdS. The CdS/ZnS nanocrystals were stabilized in Pluronic F127 block copolymer micelles, offering an optically and colloidally stable contrast agents for in vitro and in vivo imaging. Photostability test exhibited that the ZnS protective shell not only enhances the brightness of the QDs but also improves their stability in a biological environment. An in vivo imaging study showed that F127 CdS/ZnS micelles had strong luminescence. These results suggest that these nanoparticles have significant advantages for bioimaging applications and may offer a new direction for the early detection of cancer in humans.", "author_names": [ "Li-wei Liu", "Siyi Hu", "Ying Pan", "Jia-qi Zhang", "Yue-shu Feng", "Xi-he Zhang" ], "corpus_id": 16422173, "doc_id": "16422173", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Optimizing the synthesis of CdS/ZnS core/shell semiconductor nanocrystals for bioimaging applications", "venue": "Beilstein journal of nanotechnology", "year": 2014 } ]

[ { "abstract": "Thermoelectric devices can provide clean energy conversion and are environmentally friendly. However, few studies have been conducted to understand the dynamic characteristics of (thermoelectric generators) TEGs. The stability of output performance plays a very important role in TEG. Based on the thermoelectric effect and heat transfer theory, a dynamic model for waste heat recovery in a general TEG was developed to asses the influence of heat reservoir and heat sink. The validity of the theoretical model was demonstrated by experiments and it was found that the model prediction agrees well with the experimental results. The dynamic response characteristics, such as hot and cold semiconductor surface temperatures, maximum output power and system efficiency, were studied using this dynamic model. The results showed that enhancing heat dissipation on cold side is the crucial to improve the output performance of TEG, and that the fluctuation of hot reservoir leads to rapid change of output power generated by TEG, which is dangerous to electric devices. The dynamic model proposed in the present study can be used in the design and operation analysis of TEGs.", "author_names": [ "Xiaolong Gou", "Suwen Yang", "Heng Xiao", "Qiang Ou" ], "corpus_id": 110784025, "doc_id": "110784025", "n_citations": 100, "n_key_citations": 3, "score": 1, "title": "A dynamic model for thermoelectric generator applied in waste heat recovery", "venue": "", "year": 2013 }, { "abstract": "Abstract Waste heat recovery using a thermoelectric generator (TEG) is a promising approach for vehicle original equipment manufacturers to reduce fuel consumption and lower CO2 emissions. A TEG can convert otherwise wasted thermal energy from engines to electricity directly for use in the vehicle systems. This paper focuses on the development of a dynamic model of TEG system designed for vehicle waste heat recovery, which is made up of counter flow heat exchangers (HXRs) and commercial thermoelectric modules (TEMs) The model is built from thermoelectric materials into a TEM and then into a TEG system. Compared to other TEG models, the tuning and validation process of the proposed model is more complete. Experiments are done on both a TEM test rig and a heavy duty diesel engine, which is equipped with a prototype TEG on the exhaust gas recirculation (EGR) path. Simulations of steady state operating points as well as the response to typical engine cycle test show good agreement with experimental data. A TEG installed upstream of the after treatment system in a heavy duty truck has been modelled to predict the temperatures and power output in a dynamic driving cycle. The simulation results of temperatures show the model can be used as a basis to develop a control system for dynamic operation to ensure safety operation of TEG and efficient operation of the after treatment system. A comparison of power output of the systems under different scenarios underlines the importance of integration of TEM with HXRs. Based on the simulation results, around 20% average power output increase can be expected by optimizing the thermal contact conductance and the heat transfer coefficient of hot side HXR.", "author_names": [ "Song Lan", "Zhijia Yang", "Rui Chen", "Richard K Stobart" ], "corpus_id": 49363746, "doc_id": "49363746", "n_citations": 86, "n_key_citations": 3, "score": 0, "title": "A dynamic model for thermoelectric generator applied to vehicle waste heat recovery", "venue": "", "year": 2018 }, { "abstract": "The use of thermal energy dissipated from technical processes is an important step on the way towards a more sustainable society. Due to new working fluids and materials, available technologies like the thermal Organic Rankine Cycle or the Thermoelectric Generator are reaching efficiency levels making them also feasible economically. Currently, the decision on one of the existing technologies, the system design, and the applied control strategy is mainly based on rules of thumb. To foster an unbiased approach, in this contribution scalable dynamic simulation models described with the component based modeling language Modelica are proposed. A realistic example shows how these models can be used to comparatively evaluate different system layouts for efficiency and profitability.", "author_names": [ "Felix Felgner", "Lukas Exel", "Georg Frey" ], "corpus_id": 32401559, "doc_id": "32401559", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Model based design and validation of waste heat recovery systems", "venue": "2012 IEEE International Energy Conference and Exhibition (ENERGYCON)", "year": 2012 }, { "abstract": "Thermoelectric generator technology,due to its several kinds of advantages,especially its promising applications to recover waste heat,has become a noticeable researcher direction.Thermoelectric technology involves three basic effects,which lead to the temperature distribution being difficult to solve.In order to explore operation law which makes thermoelectric generator have a bigger output power,a mathematical model based on thermoelectric principle and heat transfer theory has been built and was used to solve the temperature distribution of thermoelectric generator.The performance characteristics of thermoelectric generator in different operation conditions have been gained in the objective function of output power by simulating.By the comparison,it is found that reinforcing the heat transfer capability is an effective approach and the water is superior to the air for the cooling effect.The results can provide meaningful guidelines for optimizing operation conditions and improving output power of thermoelectric generator.", "author_names": [ "Gou Xiaolong" ], "corpus_id": 113162407, "doc_id": "113162407", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Simulation on Performance of Thermoelectric Generator Applied in Waste Heat Recovery", "venue": "", "year": 2012 }, { "abstract": "Waste heat recovery, using thermoelectric power technology, is a promising approach to reduce fuel consumption and CO2 emissions on passenger cars. However, possible application requires optimizing heat exchangers and defining adequate thermoelectric materials to improve efficiency. A dynamic model has been developed to investigate the application of a thermoelectric generator (TEG) for waste heat recovery in an automotive engine exhaust. The converted electrical energy is used to charge a 12 V battery. The model evaluates the amount of recovered energy over a prescribed drive cycle. It also evaluates the effect of system integration on the TEG performances, such as fuel consumption, temperatures downstream of the TEG and the relative counter pressure. Experiments are done on both a thermoelectric module (TEM) test rig and a diesel engine test rig equipped with a TEG prototype. Simulations of steady operating points show good agreement with experimental data. The results show a maximum power of 42 W generated by the TEG, with a maximum power of 1.5 W per module (corresponding to TEM hot side temperature of 671 K and TEM cold side temperature of 354 K) At the end of the duty cycle, the energy recovered by the vehicle battery is around 27 kJ (7.5 Wh) The engine counter pressure exceeds 30 mbar when the mass flow rate is higher than 36 g s 1. The simulation results of temperatures, pressures, and output power show that the model can be used as a basis to develop a TEG with high performance that ensure safety operation of the engine and the after treatment system.", "author_names": [ "A Nour Eddine", "H Sara", "David Chalet", "Xavier Faure", "Luc Aixala", "M Cormerais" ], "corpus_id": 104321703, "doc_id": "104321703", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Modeling and Simulation of a Thermoelectric Generator Using Bismuth Telluride for Waste Heat Recovery in Automotive Diesel Engines", "venue": "Journal of Electronic Materials", "year": 2019 }, { "abstract": "A numerical model has been developed to simulate coupled thermal and electrical energy transfer processes in a thermoelectric generator (TEG) designed for automotive waste heat recovery systems. This model is capable of computing the overall heat transferred, the electrical power output, and the associated pressure drop for given inlet conditions of the exhaust gas and the available TEG volume. Multiple filled skutterudites and conventional bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from exhaust into usable electrical power. Heat transfer between the hot exhaust gas and the hot side of the TEMs is enhanced with the use of a plate fin heat exchanger integrated within the TEG and using liquid coolant on the cold side. The TEG is discretized along the exhaust flow direction using a finite volume method. Each control volume is modeled as a thermal resistance network which consists of integrated submodels including a heat exchanger and a thermoelectric device. The pressure drop along the TEG is calculated using standard pressure loss correlations and viscous drag models. The model is validated to preserve global energy balances and is applied to analyze a prototype TEG with data provided by General Motors. Detailed results are provided for local and global heat transfer and electric power generation. In the companion paper, the model is then applied to consider various TEG topologies using skutterudite and bismuth telluride TEMs.", "author_names": [ "B N Sharma", "G Naresh Babu", "A Akhil" ], "corpus_id": 56395228, "doc_id": "56395228", "n_citations": 32, "n_key_citations": 6, "score": 0, "title": "Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling and Baseline Model Analysis", "venue": "", "year": 2017 }, { "abstract": "Abstract In order to face with the increasing EU restrictions on CO2 emissions from light duty vehicles, concepts such as the engines downsizing, stop/start systems as well as more costly full hybrid solutions and Waste Heat Recovery (WHR) technologies have been proposed in the last years by OEMs. WHR technologies include Thermo Electric Generator (TEG) Organic Rankine Cycle (ORC) and Electric Turbo Compound (ETC) that have been practically implemented on few heavy duty applications but have not been proved yet as effective and affordable solutions for passenger cars. The paper deals with the analysis of opportunities and challenges of TEG and ETC technologies for a compact car, powered by a turbocharged SI engine. Specifically, the benefits achievable by TEG and ETC have been investigated by simulation analyses carried out by a dynamic engine vehicle model, validated against steady state and transient experimental data. The in cylinder processes and friction losses of the engine are modeled by a black box scalable parametric approach while grey box dynamic models are applied for intake/exhaust manifolds and turbocharger. The TEG model is based on existing and commercial thermoelectric materials, specifically Bi2Te3. The simulations have been carried out considering standard driving cycles (i.e. NEDC, WLTC) and the results evidence that significant improvement of fuel economy and CO2 reduction can be achieved by suitable management and configuration of the WHR systems, depending on engine speed and load and auxiliaries demand.", "author_names": [ "Ivan Arsie", "Andrea Cricchio", "Cesare Pianese", "Vincenzo Ricciardi", "Matteo De Cesare" ], "corpus_id": 111908398, "doc_id": "111908398", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "Modeling Analysis of Waste Heat Recovery via Thermo Electric Generator and Electric Turbo Compound for CO2 Reduction in Automotive SI Engines", "venue": "", "year": 2015 }, { "abstract": "In the face of the internationally tightened requirements and regulations for CO2 emissions from the transportation sector, waste heat recovery using a thermoelectric generator (TEG) has become the most significant research interest. A vehicular TEG, converting otherwise wasted thermal energy from engines to electricity directly for use in the vehicle systems, is a promising approach for vehicle original equipment manufacturers (OEMs) to reduce fuel consumption and lower CO2 emissions. This thesis aims to explore the main challenges to be faced in the commercialization of TEGs. Based on a review of the literature, four research gaps have been identified, which are respectively: Translating the material improvements into TEG Performance, Transient behaviors of vehicular TEGs under driving cycles, Fuel saving percentage and cost benefit estimation of TEG, Bidirectional characteristic of TEM and bifunctional vehicular TEG. To directly address these research gaps, a quasi static TEM model, a dynamic TEG model, a semi empirical vehicular TEG model, and a dual model TEM model have been respectively developed and validated through experiments on both TEM test rigs and TEG engine test benches. These developed models are used as tools to investigate the performance of TEG, parameters sensitivity, and integration effects. Model based TEG control, TEG cost benefit ratio and feasibility of a bifunctional TEG are also explored based on the developed models. The simulation results show that TEG power generation is highly sensitive to the heat transfer coefficient of hot side heat exchanger and thermal contact resistance. The TEG installation position is identified as the most important integration effect. It has been found by the simulation result that the fuel saving with TEG installed upstream of the three way catalyst (TWC) is 50% higher than the fuel saving with TEG installed downstream of the TWC. The fuel saving percentage for a skutterudite vehicular TEG, which can generate around 400 600W in constant speed 120km/h, is 0.5 3.6% depending on the integration position in the exhaust line. A 3 minute faster warm up effect of engine oil can be obtained when the bifunctional TEG works in engine warm up mode with electrical current applied.", "author_names": [ "Song Lan" ], "corpus_id": 139845107, "doc_id": "139845107", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The role of thermoelectric generator in the efficient operation of vehicles", "venue": "", "year": 2018 }, { "abstract": "A thermoelectric generator (TEG) converts thermal energy into electrical energy corresponding to temperature gradient across both hot and cold surfaces with a conversion efficiency of approximately 5% In spite of the conversion efficiency, TEGs can be implemented effectively for waste heat recovery systems within the power rating of kilowatts. The insufficiency of natural resources, frequently increasing oil costs and emission regulations have become an incentive factor of the recent increased interest in TEG applications. This thesis introduces a practical implementation of the thermoelectric generator for an automotive exhaust system which has a rapid transient response to produce electrical energy from the waste heat which flows through the exhaust pipe. In addition to automotive TE power generator implementation, an H Bridge DC DC converter within the operation of maximum power point tracking method is introduced in this thesis to obtain the maximum power transfer between the thermoelectric power generator and the load. This thesis presents a transient solution to the two dimensional heat transfer equation with variant ambient temperature that determines heat transfer and electrical potential across the thermoelectric pellet. This equation is applied into a designed two dimensional heat transfer MATLAB model and a comparison of simulation and experimental results approves the accuracy of the designed model. In addition to heat transfer simulation, a dynamic large scale thermoelectric power generator simulation program is introduced in this thesis to provide data analysis of actual implementation.", "author_names": [ "Volkan Akdogan" ], "corpus_id": 114085321, "doc_id": "114085321", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Thermoelectric power generator for automotive applications", "venue": "", "year": 2016 }, { "abstract": "The US Department of Energy's National Renewable Energy Laboratory (NREL) has developed an integrated heat exchanger/thermoelectric power system analysis tool (in Matlab/Simulink environment) that simultaneously analyzes and optimizes the integrated effects of heat exchanger and thermoelectric power generator (TEPG) performance in light duty passenger (LDP) and heavy duty (HD) vehicle waste heat recovery applications. Part I of this two part paper describes the mathematical basis of this analysis approach as applied to TEPGS using single material and segmented leg thermoelectric (TE) couples. The integrated system analysis approach to heat exchanger/TEPG system performance allows NREL to simultaneously quantify the effects of important system design parameters, and heat exchanger and TEPG device design details on performance and power output in LDP and HD vehicles of interest. Part I discusses system power maximization, potential electrical power available, and cold side cooling mass flow requirements in LDP vehicle exhaust heat recovery applications. The model has been used in Part II of this technical paper to: (1) further investigate the behavior and interdependence of important thermal and TEPG system design parameters, and (2) predict potential TE system power output for a variety of thermal conditions in LDP and HD vehicles.", "author_names": [ "Terry J Hendricks", "Jason A Lustbader" ], "corpus_id": 195861437, "doc_id": "195861437", "n_citations": 24, "n_key_citations": 3, "score": 0, "title": "Advanced thermoelectric power system investigations for light duty and heavy duty applications. I", "venue": "Twenty First International Conference on Thermoelectrics, 2002. Proceedings ICT '02.", "year": 2002 } ]

[ { "abstract": "In this paper, a dual wavelength chaotic light source is proposed and demonstrated based on a fiber ring laser (FRL) with a semiconductor optical amplifier (SOA) as the intra cavity gain element. By properly adjusting the bias current and the polarization, the SOA FRL generates a high dimension chaotic optical output with 24 nm optical bandwidth. The temporal instability of the output originates from the optical feedback, as well as the nonlinear effects of both the SOA and the long fiber. With optical to electrical conversion, the output electrical signal presents a bandwidth of 13 GHz, which is only limited by the bandwidth of the detection system. By inserting a tunable bandpass filter (TBPF) into the cavity, the chaotic emission bandwidth is limited to 3.2 nm. The output is then divided into two parallel channels using a wavelength division multiplexer (WDM) Autocorrelation of the two outputs confirms fair randomness, while the cross correlation result verifies the independence of the two. With multi bit sampling and over sampling, dual channel true random number generation (TRNG) up to 960 Gbps per channel is achieved. Random sampling periods are adopted to reduce the influence of the time delay signature (TDS) which originates from the round trip delay of the laser cavity and affects the randomness of the output. At a significance level of 0.01 and a random sampling ratio of 10 4 the generated random bits can pass all the tests provided by the NITS SP800 22 test tool.", "author_names": [ "Yuhui Wan", "Zhi'e Zhang", "Zhengying Li", "Honghai Wang", "Xuelei Fu" ], "corpus_id": 182501873, "doc_id": "182501873", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "A multi wavelength chaotic light source based on a semiconductor optical amplifier fiber ring laser", "venue": "Other Conferences", "year": 2019 }, { "abstract": "We report dual wavelength mode locked operation of a passively mode locked Er doped fiber laser (EDFL) including two sections of a fiber with equal length, one right hand twisted and another left hand twisted, and a double pass amplifier with Faraday Mirror (FM) The configuration allows cancellation of the influence of both linear and circular birefringence and strict control of the polarization of pulses in the cavity. Depending on the polarization azimuth we observed synchronous dual wavelength, 1532 nm and 1560 nm, noise like pulses (NLP) and desynchronized soliton emission.", "author_names": [ "L A Rodriguez-Morales", "Ivan Armas-Rivera", "H Santiago-Hernandez", "Baldemar Ibarra-Escamilla", "Manuel Duran-Sanchez", "Marco V Hernandez-Arriaga", "Eugene A Kuzin" ], "corpus_id": 197660717, "doc_id": "197660717", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Study of dual wavelength quasi mode locked regimes in a strict polarization controlled Er fiber ring laser", "venue": "LASE", "year": 2019 }, { "abstract": "Abstract Optical fiber amplifier is a vital device in optical communication system, which can directly amplify optical signal. We theoretically propose a type of few mode quantum dots doped fiber amplifier (FM QDFA) in this paper, capable of providing amplification for a number of linear polarization (LP) signal mode groups. The main part of the amplifier is a ring core fiber doped with PbS quantum dots. And refractive index difference between the annular area and cladding is set to 0.035, which weakens the modal coupling between different LP mode groups. The simulation results show that the ring core optical fiber not only supports transmission for LP(L=0~6,1) signal mode group, but also provides relatively uniform gain for LP(L=1~3,1) signal mode group across the wavelength band 1500 nm 1630 nm that covers the C L band. For these three signal modes, we explore the differential modal gain (DMG) under 11 pump mode groups (LP(L=0~10,1) Noticing that the highest gain for LP(1,1) signal mode is approximately 31 dB obtained at the wavelength of 1530 nm and the DMG is less than 0.5 dB with a LP (7,1) pumping mode.", "author_names": [ "Yana Shang", "Yanan Kang", "Lingmin Xu", "Fufei Pang", "Yanhua Dong", "Na Chen", "Jianxiang Wen", "Zhenyi Chen", "Tingyun Wang" ], "corpus_id": 164701126, "doc_id": "164701126", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Few mode ring core quantum dots doped optical fiber amplifier", "venue": "Optical Fiber Technology", "year": 2019 }, { "abstract": "Abstract All optical clock recovery (CR) from 20 Gbit/s nonreturn to zero differential phase shift keying (NRZ DPSK) signals are demonstrated experimentally by using a polarization maintaining fiber loop mirror filter (PMF LMF) and a semiconductor optical amplifier (SOA) fiber ring laser. Only by adjusting polarization controller (PC) NRZ DPSK signals were conveniently and fast converted to pseudo return to zero (PRZ) signal via PMF LMF. Then the PRZ signals are injected into the SOA fiber laser for CR. The recovered clock signals is with the extinction ratio (ER) of 10 dB and the root mean square (RMS) timing jitter of 750 fs in 2 31 1 long pseudorandom binary sequence (PRBS) NRZ DPSK signals measurement. Moreover, the broad wavelength tunability of recovered clock stemmed from the use of SOAs as modulator and the gain medium are shown too.", "author_names": [ "Fei Wang", "Yu Yu", "Xi Huang", "Xinliang Zhang" ], "corpus_id": 120480335, "doc_id": "120480335", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "All optical clock recovery of 20 Gbit/s NRZ DPSK signals using polarization maintaining fiber loop mirror filter and semiconductor optical amplifier fiber ring laser", "venue": "", "year": 2009 }, { "abstract": "We present a single frequency thulium doped fiber laser (TDFL) with a narrow linewidth of 20 kHz. Stable single longitudinal mode (SLM) lasing operation at 1957 nm is achieved using a segment of un pumped polarization maintaining thulium doped fiber (PM TDF) as an ultra narrow bandwidth filter. A high optical signal to noise ratio (OSNR) of over 60 dB is obtained and a high power of over 400 mW is achieved with a high slope efficiency ~45.8% thulium doped fiber amplifier (TDFA)", "author_names": [ "Taoce Yin", "Yufu Song", "Xiaogang Jiang", "Feihong Chen", "Sailing He" ], "corpus_id": 174811209, "doc_id": "174811209", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "400 mW narrow linewidth single frequency fiber ring cavity laser in 2 um waveband.", "venue": "Optics express", "year": 2019 }, { "abstract": "A reconfigurable and tunable multi tap bandpass microwave photonic filter based on a hybrid gain assisted multi wavelength fiber ring laser (HMFRL) is proposed and experimentally demonstrated. The HMFRL containing a hybrid gain medium and a high birefringence fiber loop mirror serves as the multiple taps generator for the microwave photonic filter. In order to realize a bandpass filter, the multiple taps are phase modulated, then the modulated signal is launched into a coil of dispersion compensating fiber to introduce different time delays for each tap. As a result, a bandpass response is obtained at the output of a high speeding photodetector. By adjusting the bias of the semiconductor optical amplifier from 344 to 450 mA, the number of multiple taps can be increased without optical signal to noise ratio degradation. Thus, a multi tap bandpass microwave photonic filter with bandwidth reconfiguring from 449 to 274 MHz is achieved. In addition, by changing the length of polarization maintaining fiber in the high birefringence fiber loop mirror, the wavelength spacing of the multiple taps can be adjusted, making the bandpass microwave photonic filter's free spectral range tunable.", "author_names": [ "Mengmeng Peng", "Feng-Xia Wang", "Lun Shi", "Jingxin Huang", "Wen Kang" ], "corpus_id": 208509658, "doc_id": "208509658", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Reconfigurable and tunable multi tap bandpass microwave photonic filter based on a hybrid gain assisted multi wavelength fiber ring laser", "venue": "", "year": 2019 }, { "abstract": "We experimentally characterize a fiber based ring resonator constructed from two commercially available 2x2 polarization maintaining directional couplers. This ring resonator has a maximum noise suppression of 25 dB and resonant transmission of 80% at 1550 nm. Its high transmission means this ring resonator is ideally suited for the spectral filtering of master oscillator power amplifier light sources in a robust, compact, and all fiber package. The limits of such a ring resonator for use in gravitational wave detectors are discussed, and we show how it could be used to filter the low power amplifier section and reduce the noise suppression requirements for the final free space mode cleaner.", "author_names": [ "J L H Mik", "B M Sparkes", "Christopher Perrella", "Philip S Light", "Sebastian W S Ng", "Andre Nicholas Luiten", "D J Ottaway" ], "corpus_id": 201269198, "doc_id": "201269198", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High transmission fiber ring resonator for spectral filtering of master oscillator power amplifiers", "venue": "OSA Continuum", "year": 2019 }, { "abstract": "We demonstrate the dual wavelength quasi mode locked operation of a passively mode locked Er doped fiber ring laser with twisted fiber in the cavity and a double pass amplifier with a Faraday mirror. The configuration allows very strict control of the polarization. We observed synchronous dual wavelength generation of noise like pulses (NLP) with spectra centered at 1534 nm and 1562 nm. Rotation of the azimuth of the radiation propagating in the cavity caused a switching between the generation of NLPs and packets of pulses with typical solitons spectrum. In the latter regime, we observed partially synchronous sub pulses at two different wavelengths.", "author_names": [ "L A Rodriguez-Morales", "H Santiago-Hernandez", "Olivier Pottiez", "Y E Bracamontes-Rodriguez", "Baldemar Ibarra-Escamilla", "Manuel Duran-Sanchez", "Marco V Hernandez-Arriaga", "M Avazpour", "Georgina Beltran-Perez", "Evgeny A Kuzin" ], "corpus_id": 125793136, "doc_id": "125793136", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Dual wavelength quasi mode locked regimes of an Er doped fiber ring laser", "venue": "", "year": 2018 }, { "abstract": "An all fiber S band mode locked Er doped fiber ring laser operated at 1503 nm is experimentally demonstrated by utilizing the polarization additive pulse mode locking (P APM) mechanism. To the best of our knowledge, it is the first P APM mode locked fiber laser operating in the S band. The gain medium is an S band Er doped fiber amplifier (EDFA) composed of two Er doped fiber stages with the technique of depressed cladding to cut off the fundamental mode. Stable single pulse operation is achieved within the available pump power range. Besides, characterization of the S band EDFA module, such as the wavelength dependences of the gain and noise figure, the slope efficiency, as well as the dependence of the pump power on the gain for different input powers is performed. In addition, analysis of the proposed S band mode locked fiber laser, such as the pump power dependence of the pulse width and optical bandwidth, and pulse width compression is also provided.", "author_names": [ "Ling-Gang Yang", "Siao-Shan Jyu", "Chi Wai Chow", "Chien-Hung Yeh", "Yinchieh Lai" ], "corpus_id": 55625470, "doc_id": "55625470", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "S band pulse generation by polarization additive pulse mode locking in an erbium doped all fiber ring laser", "venue": "", "year": 2014 }, { "abstract": "We describe a simple, narrow linewidth, tunable fiber based laser with a high degree of tuning accuracy. A polarization independent semiconductor optical amplifier (SOA) is used as the gain medium in a unidirectional fiber ring cavity with a circulator connected to a 6 meter long chirped fiber Bragg grating (CFBG) The laser wavelength is chosen by setting the modulation frequency of the SOA the same as the harmonics of the fundamental repetition rate of the light reflected at a specific point on the CFBG. Careful management of the drive current and pulse width helps to generate laser light of narrow linewidth (less than 0.03 nm) with low power variation (1.46 dB) over a tuning range of 40 nm.", "author_names": [ "Xiong Yang", "Robert Lindberg", "Walter Margulis", "Krister Frojdh", "F Laurell" ], "corpus_id": 155283272, "doc_id": "155283272", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Continuously tunable, narrow linewidth laser based on a semiconductor optical amplifier and a linearly chirped fiber Bragg grating.", "venue": "Optics express", "year": 2019 } ]

[ { "abstract": "Successful transition from today's general purpose programmable systems, based on the concept of planar topology, to tomorrows intelligent, highly adaptable and not necessarily programmable systems would require integration of several unorthodox approaches. We cannot predict exactly which technology will become post CMOS and post silicon computing mainstream. Whether it will belong to a quantum, molecular, DNA, optical, or neural paradigm, several speculations can be made to ease the transition and to create a processing infrastructure that will allow coexistence of today's semiconductor based approach with its successor. An attempt is made here to introduce such a transitional architecture. The proposed concept of system architecture allows high performance computing capabilities and high density free space optical interconnects to be seamlessly integrated with power supply and cooling subsystems. This is achieved by bringing twenty hexagon base and twelve pentagon base pyramids into close proximity, forming truncated icosahedron. Each pyramid is an Integrated Processing Power supply Cooling Module (IPPCM) IPPCM has a conical cavity within, which is occupied by a power supply/cooling unit; the optoelectronic components are attached to the faces of the pyramids. In the proposed instance, 180 trapezoidal multi chip processing modules, with total die attach area equal to 2000cm2, are brought into a volume of less than two liters. By bringing multiple pyramids into close proximity to each other, a free space optical link is formed for inter pyramidal communication. Some of the spaces formed between pyramids can be used for future unorthodox processing technologies.", "author_names": [ "V V Gorelik" ], "corpus_id": 109203399, "doc_id": "109203399", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "High performance computing based on 3D system assembly", "venue": "SPIE Optics Photonics", "year": 2000 }, { "abstract": "Emerging nanoscale devices hold tremendous potential in terms of integration density, low power operation and switching speed. Unlike CMOS devices, however, majority of these devices are not suitable for implementing cascaded, irregular logic structure. On the other hand, dense and periodic structures of most emerging nanodevices as well as their bi stable nature make them amenable to large high density memory array design. Moreover, self assembly of many nanostructures is efficient for a bottom up system design flow. Hence, reconfigurable computing paradigms that use memory as underlying computing element, appear promising for these devices. In this paper, first we study nanoscale FPGA, which extends conventional spatial CMOS FPGA architecture using nanoscale memory and interconnect. Next, we focus on a time multiplexed memory based computing paradigm that employs two dimensional memory for improved performance, integration density and resource usage.", "author_names": [ "Somnath Paul", "Swarup Bhunia" ], "corpus_id": 15508547, "doc_id": "15508547", "n_citations": 15, "n_key_citations": 2, "score": 0, "title": "Computing with nanoscale memory: Model and architecture", "venue": "2009 IEEE/ACM International Symposium on Nanoscale Architectures", "year": 2009 }, { "abstract": "The assembly of integrated circuits in three dimensions (3D) provides a possible solution to address the ever increasing demands of modern day electronic devices. It has been suggested that by using the third dimension, devices with high density, defect tolerance, short interconnects and small overall form factors could be created. However, apart from pseudo 3D architecture, such as monolithic integration, die, or wafer stacking, the creation of paradigms to integrate electronic low complexity cellular building blocks in architecture that has tile space in all three dimensions has remained elusive. Here, we present software and hardware foundations for a truly 3D cellular computational devices that could be realized in practice. The computing architecture relies on the scalable, self configurable and defect tolerant cell matrix. The hardware is based on a scalable and manufacturable approach for 3D assembly using folded polyhedral electronic blocks (E blocks) We created monomers, dimers and 2 x 2 x 2 assemblies of polyhedral E blocks and verified the computational capabilities by implementing simple logic functions. We further show that 63.2% more compact 3D circuits can be obtained with our design automation tools compared to a 2D architecture. Our results provide a proof of concept for a scalable and manufacture ready process for constructing massive scale 3D computational devices.", "author_names": [ "Shivendra Pandey", "Nicholas J Macias", "Carmen Ciobanu", "ChangKyu Yoon", "Christof Teuscher", "David H Gracias" ], "corpus_id": 593274, "doc_id": "593274", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Assembly of a 3D Cellular Computer Using Folded E Blocks", "venue": "Micromachines", "year": 2016 }, { "abstract": "High bandwidth density silicon photonic interconnects offer the potential to address the massive increase in bandwidth demands for data center traffic and high performance computing. One of the major challenges in realizing silicon photonics transceivers is the integration and packing of photonic ICs (PIC) with electronic ICs (EIC) This paper presents our version one, 2.5D integrated multi chip module (MCM) transceiver for 4 channel wavelength division multiplexing (WDM) operation, targeting 10 Gbps per channel. We identify five key areas critical to successful integration of MCM transceivers, which we have used in developing our version two MCM transceiver: integration architecture, equivalent circuit model development, PIC to EIC interface modelling, MCM I/O design, and design for assembly.", "author_names": [ "Nathan C Abrams", "Qixiang Cheng", "Madeleine Strom Glick", "Evgeny Manzhosov", "Moises A Jezzini", "Padraic E Morrissey", "Peter O'Brien", "Keren Bergman" ], "corpus_id": 211483227, "doc_id": "211483227", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Design considerations for multi chip module silicon photonic transceivers", "venue": "", "year": 2020 }, { "abstract": "During last couple years, the market of IC packag successful to implement Cu pillar Bump as a mainstream of high density flip chip packaging solution in each of product application market. High performance computing product requires advanced Si node, large die and multiple die side by side floor plan on large FCBGA. However, large scale die dimension and substrate form factor to brings up expensive wafer mask fabrication, substrate fee, complex backend assembly process control and specific bill of material to maintain better mechanical performance. In other words, there is a significant help from package assembly since Moore Law is slowing down. After reviewed the package evolution trend of 2.5D package, Cu pillar bump owns better electron migration performance which is suitable for high power and low latency product application. 3D package with mBump architecture has three kinds of advantages. First, die partition to shrink die area and enhance wafer yield; Second, reduce signal latency insertion loss compared to 2.5D since applying 50um TSV wafer thick. to reduce signal transmission path; Third, high power IC which used advanced Si node and put on top position of 3D stacking to contact thermal interface material and heat sink directly to realize better system thermal dissipation requirement.In order to well define optimum construction while utilizing less than 30um mBump pitch 3D package vehicle rely on mechanical simulation trend to find out critical dimension on mBump of top die and TSV wafer structure design. The paper will compare die to die signal connection architecture such as 2.5D, FO MCM and FO EB packages. Uses a series of fundamental studies to define mBump stack up composition and protection material in terms of 3DIC platform baseline establishment. Based on dominated key factors of stress simulation and actual verification result to find out bump joint methodology. First of all, chip module of 3D TV (Test Vehicle) samples is stacked with top die and bottom die by the joint of mBump and mPad. mBump has three structures: CS (Cu Solder) CNS (Cu Ni Solder) and CNCS (Cu Ni Cu Solder) Moreover, the validation flow is proposed. In the first phase, the metallic reaction test of 1st 3D TV samples and stress simulation of mBump are performed. In the second phase, based on the results of the first phase, to modify the dimension and materials of mBump and mPad, and to build the 2nd 3D TV samples for reflow test then obtain the best combination of structure and dimension for mBump by multiple reflow test.In conclusion, this study successfully completed pathfinding activity of 3D package with the joint of mBump (less than 15/30, mm) and mPad, and found the best structure and dimension for mBump and mPad.", "author_names": [ "Nistec Chang", "C Key Chung", "Yu-Po Wang", "C F Lin", "P J Su", "Teny Shih", "N H Kao", "Joseph Hung" ], "corpus_id": 225823755, "doc_id": "225823755", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "3D Micro Bump Interface Enabling Top Die Interconnect to True Circuit Through Silicon Via Wafer", "venue": "2020 IEEE 70th Electronic Components and Technology Conference (ECTC)", "year": 2020 }, { "abstract": "Designing high speed and low power interconnects is a challenge for high performance computing applications, while silicon photonics can provide attractive solutions to perform high density communications. This paper presents an electro optic transmitter operating at 20 Gbps (gigabit per second) as a first step toward the demonstration of chip to chip optical links. The architecture is based on a dual drive Mach Zehnder interferometer co integrated with a 55 nm CMOS driver. Design optimizations and trade offs analysis enable low energy and negligible bit error rate $BER 10^ 12} transmission at 20 Gbps, by exploring a firstly reported low extinction ratio (ER) modulator. A wire bonding board assembly is then carried out to co integrate hybrid transmitter. Co simulations are presented and show good agreement with experiments. Combined with an adequate MZM bias, this solution achieves a minimal energy consumption of 0.9 pJ/bit while ensuring a sufficiently large ER of 0.73 dB for chip to chip interconnects applications.", "author_names": [ "Audrey Michard", "J F Carpentier", "Nicolas Michit", "Patrick Le Maitre", "Philippe Benabes", "Pietro M Ferreira" ], "corpus_id": 209458001, "doc_id": "209458001", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A Sub pJ/Bit, Low ER Mach Zehnder Based Transmitter for Chip to Chip Optical Interconnects", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2020 }, { "abstract": "Abstract Effective ultra dense integrated digital information processing strains the leading edge of current chemistry and materials science, and requires hybrid top down and bottom up assembly techniques, with highly reliable defect and fault tolerant architecture. We have fabricated and assembled molecular scale logic elements based on overlapping semiconducting nanowire arrays using novel wafer scale assembly techniques. Based on breakthrough addressing techniques, we have connected these logic blocks to ultra dense memory blocks, and to external CMOS process lithographic interfaces for testing as well as test applications. Our architecture to construct highly reliable components out of high defect density logic and memory, using new sublithographic scale PLA array architectures include novel reliable circuit techniques and higher level redundancy mechanisms. Using state of the art modeling and simulation platforms, we have optimized test designs, developed defect tolerance approaches, and are continuing to develop and optimize larger systems.", "author_names": [ "Charles M Lieber" ], "corpus_id": 107424418, "doc_id": "107424418", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Assembly of Ultra Dense Nanowire Based Computing Systems", "venue": "", "year": 2006 }, { "abstract": "Nowadays, Field Programmable Gate Arrays (FPGAs) platforms offer a high density to allow designing Multi Processor based System on Chip. SPMD (Single Program Multiple Data) is a massively parallel execution model based on the assembly of a given number of homogeneous Processing Elements (PEs) This model is often relaying on Master/Slaves architecture composed by a Master PE that manages the parallel execution of a set of identical slave PEs. Furthermore, Dynamic Partial Reconfiguration (DPR) feature allows such computing system to be reconfigured on the fly for a given application requirement. Given the growing number of PEs in Master/Slaves architecture, it is difficult to estimate the time of specification and design during the phase of allocation and floorplanning of Partial Reconfigurable Regions (PRRs) because it is still performed manually. In this work, we present AFFORDe, a tool enable to automate the Xilinx DPR flow for SPMD architecture that allows parsing the resource requirements of the static and the dynamically reconfigurable parts to perform an automatic floorplanning. The floorplanning is based on a Heuristic Algorithm for Automatic Floorplanning in SPMD Architectures (HAAFSA) This tool is used to generate a configuration file that allows floorplanning of reconfigurable regions in an automatic way of a given Master/Slaves configuration. Experimental results show the effectiveness of our tool to increase the design productivity for dynamically reconfigurable SPMD based architecture.", "author_names": [ "Wissem Chouchene", "Rabie Ben Atitallah", "Jean-Luc Dekeyser" ], "corpus_id": 832809, "doc_id": "832809", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "AFFORDe: Automatic Allocation and Floorplanning for SPMD Architecture", "venue": "2016 IEEE 10th International Symposium on Embedded Multicore/Many core Systems on Chip (MCSOC)", "year": 2016 }, { "abstract": "Both bottom up and top down techniques have been used to fabricate assemblies of devices and interconnect where key, density defining feature sizes are on the order of ten atoms wide. We show how complete computing architectures can be constructed from these new techniques and building blocks despite high defect rates, extreme regularity requirements, and statistical assembly. We further highlight the paradigm shifts in integrated circuit design and architecture which appear necessary to accommodate these atomic scale effects. Our estimates suggest a 10 nm full pitch FPGA like design can achieve one to two orders of magnitude greater logic density than ideal, defect free lithographic scaling to 22 nm.", "author_names": [ "Andre DeHon" ], "corpus_id": 9021390, "doc_id": "9021390", "n_citations": 16, "n_key_citations": 3, "score": 0, "title": "Architecture approaching the atomic scale", "venue": "ESSCIRC 2007 33rd European Solid State Circuits Conference", "year": 2007 }, { "abstract": "Increasing demand for advanced electronic products with a smaller form factor, superior functionality and performance with a lower overall cost has driven semiconductor industry to develop more innovative and emerging advanced packaging technologies. Memory bandwidth has become a bottleneck to mobile processor performance and lower power consumption for high performance computing needs. To reduce obstacles, a revolution in device architecture and package technologies is require. 3D TSV (Through Silicon Via) stacking is to be one of the technologies that can meet those requirements. This paper mainly describes the 3D TSV MEOL process and packaging technology, especially TSV wafer process and thin die bonding process with Cu column bump on substrates. In order to prove the quality of this 3D package, some stress tests were conducted to evaluate the reliability on the package and board level. The innovative TSV MEOL process and flip chip assembly with micro Cu column contributes to high density and reliable 3D/TSV integrations has been developed and demonstrated. The target package had two tier structures which consisted of a 28 nm logic device and Wide I/O memory. The logic device was fabricated by via middle process and accompanied with over 1200 TSVs, and 40 mm 50 mm bump pitch layout. Advanced 300mm backside via reveal (BVR) process was developed with thin wafer handling and temporary bonding/debonding process. Thermocompression bonding method with Cu pillar was applied to both connections between the memory die and the logic die and between the logic die and an organic substrate so that the high reliability could be achieved. As reliability test items, temperature cycling test, high temperature storage test, humidity test, unbiased highly accelerated stress test and pressure cooker test were performed and passed JEDEC standard reliability tests as well as board level reliability test. After functional test with stacked 3D TSV with logic and Wide IO memory, 12.8 GB/s transmission and drastic I/O power saving compared to LPDDR3 were observed.", "author_names": [ "Duk Ju Na", "KyawOo Aung", "Won Kyung Choi", "Tsuyoshi Kida", "Toshihiko Ochiai", "Tomoaki Hashimoto", "Michitaka Kimura", "Keiichiro Kata", "Seung Wook Yoon", "Andy Chang Bum Yong" ], "corpus_id": 19131849, "doc_id": "19131849", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "TSV MEOL (Mid End of Line) and packaging technology of mobile 3D IC stacking", "venue": "2014 IEEE 64th Electronic Components and Technology Conference (ECTC)", "year": 2014 } ]

[ { "abstract": "A subwavelength water metamaterial is proposed and analyzed for ultra broadband perfect absorption at microwave frequencies. We experimentally demonstrate that this metamaterial shows over 90% absorption within almost the entire frequency band of 12 29.6 GHz. It is also shown that the proposed metamaterial exhibits a good thermal stability with its absorption performance almost unchanged for the temperature range from 0 to 100*C. The study of the angular tolerance of the metamaterial absorber shows its ability of working at wide angles of incidence. Given that the proposed water metamaterial absorber is low cost and easy for manufacture, we envision it may find numerous applications in electromagnetics such as broadband scattering reduction and electromagnetic energy harvesting. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (160.1245) Artificially engineered materials; (050.6624) Subwavelength structures. References and links 1. N. Engheta and R. W. Ziolkowski, Metamaterials: Physics and Engineering Explorations (Wiley IEEE, 2006) 2. F. Capolino, Theory and Phenomena of Metamaterials (CRC, 2009) 3. Y. Cui, L. Kang, S. Lan, S. Rodrigues, and W. Cai, \"Giant chiral optical response from a twisted arc metamaterial,\" Nano Lett. 14, 1021 1025 (2014) 4. A. S. Baimuratov, T. P. Pereziabova,W. Zhu,M.Yu. Leonov, A.V. Baranov, A.V. Fedorov, and I. D. Rukhlenko,\"Optical anisotropy of topologically distorted semiconductor nanocrystals,\" Nano Lett. 14, 1021 1025 (2014) 5. N. Yu and F. Capasso, \"Flat optics with designer metasurfaces,\" Nature Mater. 13, 139 150 (2014) 6. Y. Zhang, R. Zhang, X. Li, L. Ma, C. Liu, C. He, and C. Cheng, \"Radially polarized plasmonic vector vortex generated by a metasurface spiral in gold film,\" Opt. Express 25, 32150 32160 (2017) 7. D. Schurig, J. J. Mock, B. J. Justice, S. A. Cummer, J. B. Pendry, A. F. Starr, D. R. Smith, \"Metamaterial electromagnetic cloak at microwave frequencies,\" Science 314, 977 980 (2006) 8. Z. H. Jiang, S. Yun, L. Lin, J. A. Bossard, D. H. Werner, and T. S. Mayer, \"Tailoring Dispersion for Broadband Low loss Optical Metamaterials Using Deep subwavelength Inclusions,\" Sci. Rep. 3, 1571 (2013) 9. P. Tassin, Lei Zhang, Th. Koschny, E. N. Economou, and C. M. Soukoulis, \"Low loss metamaterials based on classical electromagnetically induced transparency,\" Phys. Rev. Lett. 102, 053901 (2009) 10. M. Premaratne and G. P. Agrawal, Light Propagation in Gain Media: Optical Amplifiers (Cambridge University, 2011) 11. Z. Dong, H. Liu, T. Li, Z. Zhu, S. Wang, J. Cao, S. Zhu, and X. Zhang, \"Optical loss compensation in a bulk left handed metamaterial by the gain in quantum dots,\" Appl. Phys. Lett. 96, 044104 (2010) 12. N. I. Landy, S. Sajuyigbe, J. J. Mock, D. R. Smith, and W. J. Padilla, \"Perfect metamaterial absorber,\" Phys. Rev. Lett. 100, 207402 (2008) 13. W. Zhu, F. Xiao, M. Kang, and M. Premaratne, \"Coherent perfect absorption in an all dielectric metasurface,\" Appl. Phys. Lett. 108, 121901 (2016) 14. C. M. Watts, X. Liu, and W. J. Padilla, \"Metamaterial electromagnetic wave absorbers,\" Adv. Mater. 24, OP98 OP120 (2012) Vol. 26, No. 4 19 Feb 2018 OPTICS EXPRESS 5052 #318885 https:/doi.org/10.1364/OE.26.005052 Journal (c) 2018 Received 3 Jan 2018; revised 11 Feb 2018; accepted 11 Feb 2018; published 16 Feb 2018 15. H. Wang, P. V. Sivan, A. Mitchell, G. Rosengarten, P. Phelan, and L. Wang, \" Highly efficient selective metamaterial absorber for high temperature solar thermal energy harvesting,\" Sol. Energy Mater. Sol. Cells 137, 235 242 (2015) 16. S. Gu, B. Su, and X. Zhao, \"Planar isotropic broadband metamaterial absorber,\" J. Appl. Phys. 104, 163702 (2013) 17. Y. Cui, K. H. Fung, J. Xu, H. Ma, Y. Jin, S. He, and N. X. Fang, \"Ultrabroadband light absorption by a sawtooth anisotropic metamaterial slab,\" Nano Lett. 12, 1443 (2012) 18. Y. Shen, Y. Pang, J. Wang, H. Ma, and Z. Pei, \"Ultra broadband terahertz absorption by uniaxial anisotropic nanowire metamaterials,\" IEEE Photon. Technol. Lett. 27, 2284 (2015) 19. M. Pu, M. Wang, C. Hu, C. Huang, Z. Zhao, Y. Wang, and X. Luo, \"Engineering heavily doped silicon for broadband absorber in the terahertz regime,\" Opt. Express 20, 25513 25519 (2012) 20. W. Ellison, \"Permittivity of pure water, at standard atmospheric pressure, over the frequency range 0 25 THz and the temperature range 0 100*C,\" J. Phys. Chem. Ref. Data 36, 1 18 (2007) 21. A. Andryieuski, S. M. Kuznetsova, S. V. Zhukovsky, Y. S. Kivshar, and A. V. Lavrinenko, \"Water: Promising opportunities for tunable all dielectric electromagnetic metamaterials,\" Sci. Rep. 5, 13535 (2015) 22. Y. J. Yoo, S. Ju, S. Y. Park, Y. J. Kim, J. Bong, T. Lim, K. W. Kim, J. Y. Rhee, and Y. Lee, \"Metamaterial absorber for electromagnetic waves in periodic water droplets,\" Sci. Rep. 5, 14018 (2015) 23. W. Zhu, I. D. Rukihlenko, F. Xiao, C. He, J. Geng, X. Liang, M. Premaratne, and R. Jin, \"Multiband coherent perfect absorption in a water based metasurface,\" Optics Express 25, 15737 15745 (2017) 24. Y. Pang, J. Wang, Q. Cheng, S. Xia, X. Zhou, Z. Xu, T. Cui, and S. Qu, \"Thermally tunable water substrate broadband metamaterial absorbers,\" Appl. Phys. Lett. 110, 104103 (2017) 25. M. Odit, P. Kapitanova, A. Andryieuski, P. Belov, and A. V. Lavrinenko, \"Thermally tunable water substrate broadband metamaterial absorbers,\" Appl. Phys. Lett. 109, 011901 (2016) 26. H. Tao, C. M. Bingham, A. C. Strikwerda, D. Pilon, D. Shrekenhamer, N. I. Landy, K. Fan, X. Zhang, W. J. Padilla, and R. D. Averitt, \"Highly flexible wide angle of incidence terahertz metamaterial absorber: Design, fabrication, and characterization,\" Phys. Rev. B 78, 241103(R) (2008)", "author_names": [ "", "R D" ], "corpus_id": 189920775, "doc_id": "189920775", "n_citations": 5, "n_key_citations": 1, "score": 1, "title": "Water metamaterial for ultra broadband and wide angle absorption", "venue": "", "year": 2018 }, { "abstract": "The segmentation and classification of retinal arterioles and venules play an important role in the diagnosis of various eye diseases and systemic diseases. The major challenges include complicated vessel structure, inhomogeneous illumination, and large background variation across subjects. In this study, we employ a fully convolutional network to simultaneously segment arterioles and venules directly from the retinal image, rather than using a vessel segmentation arteriovenous classification strategy as reported in most literature. To simultaneously segment retinal arterioles and venules, we configured the fully convolutional network to allow true color image as input and multiple labels as output. A domain specific loss function was designed to improve the overall performance. The proposed method was assessed extensively on public data sets and compared with the stateof the art methods in literature. The sensitivity and specificity of overall vessel segmentation on DRIVE is 0.944 and 0.955 with a misclassification rate of 10.3% and 9.6% for arteriole and venule, respectively. The proposed method outperformed the state of the art methods and avoided possible error propagation as in the segmentation classification strategy. The proposed method was further validated on a new database consisting of retinal images of different qualities and diseases. The proposed method holds great potential for the diagnostics and screening of various eye diseases and systemic diseases. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (100.0100) Image processing; (150.0150) Machine vision. References and links 1. R. F. Gariano and T. W. Gardner, \"Retinal angiogenesis in development and disease,\" Nature 438(7070) 960 966 (2005) 2. M. D. Abramoff, M. K. Garvin, and M. Sonka, \"Retinal imaging and image analysis,\" IEEE Rev. Biomed. Eng. 3, 169 208 (2010) 3. S. B. Seidelmann, B. Claggett, P. E. Bravo, A. Gupta, H. Farhad, B. E. Klein, R. Klein, M. Di Carli, and S. D. Solomon, \"Retinal vessel calibers in predicting long term cardiovascular outcomes: the atherosclerosis risk in communities study,\" Circulation 134(18) 1328 1338 (2016) 4. K. Rothaus, X. Jiang, and P. Rhiem, \"Separation of the retinal vascular graph in arteries and veins based upon structural knowledge,\" Image Vis. Comput. 27(7) 864 875 (2009) 5. Q. Hu, M. D. Abramoff, and M. K. Garvin, \"Automated construction of arterial and venous trees in retinal images,\" J. Med. Imaging (Bellingham) 2(4) 044001 (2015) 6. B. Dashtbozorg, A. M. Mendonca, and A. 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Roychowdhury, D. D. Koozekanani, and K. K. Parhi, \"Iterative Vessel Segmentation of Fundus Images,\" IEEE Trans. Biomed. Eng. 62(7) 1738 1749 (2015) 29. S. Wang, Y. Yin, G. Cao, B. Wei, Y. Zheng, and G. Yang, \"Hierarchical retinal blood vessel segmentation based on feature and ensemble learning,\" Neurocomputing 149, 708 717 (2015) 30. X. Xu, W. Ding, X. Wang, R. Cao, M. Zhang, P. Lv, and F. Xu, \"Smartphone based accurate analysis of retinal vasculature towards point of care diagnostics,\" Sci. Rep. 6(1) 34603 (2016) 31. J. Zhang, B. Dashtbozorg, E. Bekkers, J. P. W. Pluim, R. Duits, and B. M. Ter Haar Romeny, \"Robust retinal vessel segmentation via locally adaptive derivative frames in orientation scores,\" IEEE Trans. Med. Imaging 35(12) 2631 2644 (2016) 32. G. Mirsharif, F. Tajeripour, F. Sobhanmanesh, H. Pourreza, and T. Banaee, \"Developing an automatic method for separation of arteries from veins in retinal images,\" in 1st International Conference on Computer and Knowledge Engineering (2011) Vol. 9, No. 7 1 Jul 2018 BIOMEDICAL OPTICS EXPRESS 3154", "author_names": [ "XU Xiayu", "Rendong Wang", "LV Peilin", "Bin Gao", "LI Chan", "Zhiqiang Tian", "Tao Tan", "Xuan Feng" ], "corpus_id": 214705828, "doc_id": "214705828", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Validation of a harmonic model for eddy currents in slitted conducting plates", "venue": "", "year": 2018 }, { "abstract": "We present a comparative study of electrical measurements of graphene using terahertz time domain spectroscopy in transmission and reflection mode, and compare the measured sheet conductivity values to electrical van der Pauw measurements made independently in three different laboratories. Overall median conductivity variations of up to 15% were observed between laboratories, which are attributed mainly to the well known temperature and humidity dependence of non encapsulated graphene devices. We conclude that terahertz time domain spectroscopy performed in either reflection mode or transmission modes are indeed very accurate methods for mapping electrical conductivity of graphene, and that both methods are interchangeable within measurement uncertainties. The conductivity obtained via terahertz time domain spectroscopy were consistently in agreement with electrical van der Pauw measurements, while offering the additional advantages associated with contactless mapping, such as high throughput, no lithography requirement, and with the spatial mapping directly revealing the presence of any inhomogeneities or isolating defects. The confirmation of the accuracy of reflection mode removes the requirement of a specialized THz transparent substrate to accurately measure the conductivity. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (120.4290) Nondestructive testing; (160.4236) Nanomaterials; (300.6250) Spectroscopy, condensed matter; (300.6495) Spectroscopy, terahertz; (310.3840) Materials and process characterization; (310.6870) Thin films, other properties. References and links 1. H. J. Yoon, D. H. Jun, J. H. Yang, Z. Zhou, S. S. Yang, and M. M. C. Cheng, \"Carbon dioxide gas sensor using a graphene sheet,\" Sens. Actuators B Chem. 157(1) 310 313 (2011) 2. F. Schedin, A. K. Geim, S. V. Morozov, E. W. Hill, P. Blake, M. I. Katsnelson, and K. S. Novoselov, \"Detection of individual gas molecules adsorbed on graphene,\" Nat. Mater. 6(9) 652 655 (2007) 3. A. Cagliani, D. M. A. Mackenzie, L. K. Tschammer, F. Pizzocchero, K. Almdal, and P. 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Boggild, D. M. A. Mackenzie, P. R. Whelan, D. H. Petersen, J. D. Buron, A. Zurutuza, J. Gallop, L. Hao, and P. U. Jepsen, \"Mapping the electrical properties of large area graphene,\" 2D Mater. 4(4) 042003 (2017) 23. L. Gammelgaard, J. M. Caridad, A. Cagliani, D. M. A. MacKenzie, D. H. Petersen, T. J. Booth, and P. Boggild, \"Graphene transport properties upon exposure to PMMA processing and heat treatments,\" 2D Mater. 1(3) 1 6 (2014) 24. J. D. Buron, F. Pizzocchero, P. U. Jepsen, D. H. Petersen, J. M. Caridad, B. S. Jessen, T. J. Booth, and P. Boggild, \"Graphene mobility mapping,\" Sci. Rep. 5(1) 12305 (2015) 25. J. D. Buron, D. M. A. Mackenzie, D. H. Petersen, A. Pesquera, A. Centeno, P. Boggild, A. Zurutuza, and P. U. Jepsen, \"Terahertz wafer scale mobility mapping of graphene on insulating substrates without a gate,\" Opt. Express 23(24) 30721 30729 (2015) 26. D. M. A. Mackenzie, J. D. Buron, P. R. Whelan, B. S. Jessen, A. Silajdzic, A. Pesquera, A. Centeno, A. Zurutuza, P. 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B 84(3) 035421 (2011) Vol. 26, No. 7 2 Apr 2018 OPTICS EXPRESS 9221", "author_names": [ "", "Musa M A", "W R", "S -" ], "corpus_id": 84841241, "doc_id": "84841241", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Quality assessment of terahertz time domain spectroscopy transmission and reflection modes for graphene conductivity mapping", "venue": "", "year": 2018 }, { "abstract": "We demonstrate non contact temperature measurement with one tenth of a kelvin precision at distances of several meters using omnidirectional laser emission from dye doped cholesteric liquid crystal droplets freely floating in a fluid medium. Upon the excitation with a pulsed laser the liquid crystal droplet emits laser light due to 3D Bragg lasing in all directions. The spectral position of the lasing is highly dependent on temperature, which enables remote and contact less temperature measurement with high precision. Both laser excitation and collection of light emitted by microlasers is performed through a wide telescope aperture optics at a distance of up to several meters. The optical excitation volume, where the droplets are excited and emitting the laser light is of the order of ten cubic millimeters. The measurement is performed with ten second accumulation time, when several droplets pass through the excitation volume due to their motion. The time of measurement could easily be shortened to less than a second by increasing the rate of the excitation laser. Since the method is based solely on measuring the spectral position of a single and strong laser line, it is quite insensitive to scattering, absorption and background signals, such as autofluorescence. This enables a wide use in science and industry, with a detection range exceeding tens of meters. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement OCIS codes: (120.0280) Remote sensing and sensors; (140.3945) Microcavities; (160.3710) Liquid crystals; (280.3420) Laser sensors; (280.6780) Temperature. References and links 1. P. de Gennes and J. Prost, The physics of liquid crystals (Oxford University, 1993) 2. H. Coles and S. Morris, \"Liquid crystal lasers,\" Nat. Photonics 4, 676 (2010) 3. V. I. Kopp, B. Fan, H. Vithana, and A. Z. Genack, \"Low threshold lasing at the edge of a photonic stop band in cholesteric liquid crystals,\" Opt. letters 23, 1707 1709 (1998) 4. B. Taheri, A. Munoz, P. Palffy Muhoray, and R. Twieg, \"Low threshold lasing in cholesteric liquid crystals,\"Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A. Mol. Cryst. Liq. Cryst. 358, 73 82 (2001) 5. E. Alvarez, M. He, A. Munoz, P. Palffy Muhoray, S. Serak, B. Taheri, and R. 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Green, \"Color changing cholesteric polymer films sensitive to amino acids,\" Macromolecules 39, 3986 3992 (2006)", "author_names": [ "" ], "corpus_id": 202635146, "doc_id": "202635146", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Remote and autonomous temperature measurement based on 3 D liquid crystal microlasers", "venue": "", "year": 2018 }, { "abstract": "The optical feedback dynamics of two multimode InAs/GaAs quantum dot lasers emitting exclusively on sole ground or excited lasing states is investigated. The transition from longto short delay regimes is analyzed, while the boundaries associated to the birth of periodic and chaotic oscillations are unveiled to be a function of the external cavity length. The results show that depending on the initial lasing state, different routes to chaos are observed. These results are of importance for the development of isolator free transmitters in short reach networks. 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Bimberg, \"15 Gb/s index coupled distributed feedback lasers based on 1.3 mm InGaAs quantum dots,\" Appl. Phys. Lett. 105, 011103 (2014)", "author_names": [ "H Uang", "IN LYU-CHIHL", "Christian Hen", "D Ejan A Rsenijevic", "D Ieter B Imberg", "F Rederic G Rillot" ], "corpus_id": 49657772, "doc_id": "49657772", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Multimode optical feedback dynamics in InAs GaAs quantum dot lasers emitting exclusively on ground or excited states transition from short to long delay regimes", "venue": "", "year": 2018 }, { "abstract": "We show that phase change materials can be used to switch photonic nanostructures between cloaking and superscattering regimes at mid infrared wavelengths. More specifically, we investigate the scattering properties of subwavelength three layer cylindrical structures in which the material in the outer shell is the phase change material Ge2Sb2Te5 (GST) We first show that, when GST is switched between its amorphous and crystalline phases, properly designed electrically small structures can switch between resonant scattering and cloaking invisibility regimes. The contrast ratio between the scattering cross sections of the cloaking invisibility and resonant scattering regimes reaches almost unity. We then also show that larger, moderately small cylindrical structures can be designed to switch between superscattering and cloaking invisibility regimes, when GST is switched between its crystalline and amorphous phases. 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Carr, M. et al. (2017) Beyond the \"code\" a guide to the description and documentation of biodiversity in ciliated protists (Alveolata, Ciliophora) J. Eukaryot. Microbiol. 64, 539 554. Xiong, J. Yang, W. Chen, K. Jiang, C. Ma, Y. Chai, X. Yan, G. Wang, G. Yuan, D. Liu, Y. et al. (2019) Hidden genomic evolution in a morphospecies The landscape of rapidly evolving genes in Tetrahymena. PLoS Biol. 17, e3000294.", "author_names": [ "Edgar M Medina", "Nicolas E Buchler" ], "corpus_id": 232096161, "doc_id": "232096161", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Predatory protists", "venue": "", "year": 2020 }, { "abstract": "Geometries associated relative stabilities, averaged binding energy, fragmentation energy, second order energy difference and energy gaps of V doped germanium cationic clusters GenV+ (n 9 13) have been investigated by using density functional theory with the BP86 exchange correlation potential and effective core potential (ECP) LanL2DZ basis sets. Natural population analysis charge is also examined to understand the associated charge transfer in structures of clusters. When an electron is removed from neutral cluster GenV to form the cation cluster GenV+ geometric structure of the lowest energy isomers change. The endohedral cage structure of the cation clusters appears at n 10 in the cluster Ge10V+ The lowest energy isomers of cation cluster are in triplet state or singlet state. The cluster Ge10V+ is found to be the most stable in terms of stability parameters in the all system GenV+ (n 9 13) Keywords: BP86/LANL2DZ, binding energy, V Ge clusters, structure of clusters. References [1] T. Fehlner, J. Halet, J. Saillard, Molecular Clusters: A Bridge to Solid State Chemistry, Cambridge University Press, Cambridge, 2007. https:/doi.org/10.1017/CBO9780511628887.[2] S. Djaadi, K. Eddine Aiadi, S. Mahtout, First principles study of structural, electronic and magnetic properties of SnGen(0, 1) (n 1 17) clusters, J. 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Gaussian 09, Revision C.01. Gaussian, Inc, Wallingford CT. 2010.[28] A.E. Reed, L.A. Curtiss, F. Weinhold, Intermolecular interactions from a natural bond orbital, donor acceptor viewpoint, Chem. Rev. 88(6) (1988) 899 926. https:/doi.org/10.1021/ cr00088a005.", "author_names": [ "Nguyen Huu Tho", "Trang T K Tu" ], "corpus_id": 210895050, "doc_id": "210895050", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Geometries, Stabilities and Electronic Property of Cationic Vanadium Doped Germanium Cluster GenV+ (n=9 13) from Density Functional Theory", "venue": "VNU Journal of Science: Natural Sciences and Technology", "year": 2019 }, { "abstract": "Mechanism and thermodynamical parameters of activation and reaction of model reaction underlying in the basisof chemical recycling of polycarbonates noncatalytic transesterification of diethyl carbonate by methanol are studied by B3LYP/6 311++G(df,p) quantum chemical method. Detailed description of two possible reaction mechanisms is carried out. They are: nucleophilic carbonyl atom substitution mechanism and \"addition elimination\" mechanism including allogenic addition of methanol to diethyl carbonate's carbonyl group which leads to tetrahedral intermediate formation and its further decomposition which results in new molecule of carbonate and alcohol formation. The second way that is rate limiting step characterizes by lower free energy barriers. Nevertheless, this way is problematical. It is explained by the fact that tetrahedral intermediates formation characterizes by low values of equilibrium constants. Both monomers and dimers of methanol can be involved in reactions. Reactions with methanol dimers are more kinetically preferable than reaction with methanol monomer, both in nucleophilic carbonyl atom substitution mechanism and \"addition elimination\" mechanism. It is provided by more higher donoracceptor and acid base properties of methanol dimer in comparison with methanol monomer. All reactions are carried out through cyclic approved transition states. References [1] A. Kausar. A review of filled and pristine polycarbonate blends and their applications. J. Plast. Film Sheet. 2017. Vol.34. Iss.1. P.60 97. [2] Handbook of Plastic Optics. Ed. St. Baumer. Weinheim: Wiley. 2010. 296p. [3] J. Feng, R. X. Zhuo, X. Z. Zhang. Construction of functional aliphatic polycarbonates for biomedical applications. Prog. Polym. Sci. 2012. Vol.37. Iss.2. P.211 236. [4] Advances in Biomaterials for Biomedical Applications. Eds. A. Tripathi, J. S. Melo. Syngapore: Springer. 2017. 545p. [5] E.V. Antonakou, K.G. Kalogiannis, S.D. Stefanidis, S.A. Karakoulia, K.S. Triantafyllidis, A.A. Lappas, D.S. Achilias. Catalytic and thermal pyrolysis of polycarbonate in a fixed bed reactor: the effect of catalysts on products yields and composition. Polym. Degrad. 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P.7 12.", "author_names": [ "M V Korshunov", "Nikita I Kurshev", "Alexander Y Samuilov", "Elena Prokhorova", "Ya D Samuilov" ], "corpus_id": 209493236, "doc_id": "209493236", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Quantum chemical studying of noncatalytic methanolysis of diethyl carbonate", "venue": "", "year": 2019 }, { "abstract": "Biological tissue has a complex structure and exhibits rich spectroscopic behavior. There is no tissue model up to now able to account for the observed spectroscopy of tissue light scattering and its anisotropy. Here we present, for the first time, a plum pudding random medium (PPRM) model for biological tissue which succinctly describes tissue as a superposition of distinctive scattering structures (plum) embedded inside a fractal continuous medium of background refractive index fluctuation (pudding) PPRM faithfully reproduces the wavelength dependence of tissue light scattering and attributes the \"anomalous\" trend in the anisotropy to the plum and the powerlaw dependence of the reduced scattering coefficient to the fractal scattering pudding. Most importantly, PPRM opens up a novel venue of quantifying the tissue architecture and microscopic structures on average from macroscopic probing of the bulk with scattered light alone without tissue excision. We demonstrate this potential by visualizing the fine microscopic structural alterations in breast tissue (adipose, glandular, fibrocystic, fibroadenoma, and ductal carcinoma) deduced from noncontact spectroscopic measurement. 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Jiang, \"Noninvasive evaluation of nuclear morphometry in breast lesions using multispectral diffuse optical tomography,\" PloS One 7, e45714 (2012) 22. M. Xu, M. Alrubaiee, and R. R. Alfano, \"Fractal mechanism of light scattering for tissue optical biopsy,\" in \"Optical Biopsy VI,\" vol. 6091 of Proc. SPIE, R. R. Alfano and A. Katz, eds. p. 60910E, (2006) 23. V. S. Remizovich, \"Theoretical description of elastic reflection of particles (photons) incident at grazing angles without the use of the diffusion approximation,\" Sov. Phys. JETP 60, 290 297 (1984) 24. B. J. Uscinski, H. G. Booker, and M. Marians, \"Intensity Fluctuations Due to a Deep Phase Screen with a Power Law Spectrum,\" Proc. Royal Soc. A 374, 503 530 (1981) 25. R. Michels, F. Foschum, and A. Kienle, \"Optical properties of fat emulsions,\" Opt. Express 16, 2304 2314 (2008) 26. T. T. Wu, J. Y. Qu, and M. Xu, \"Unified Mie and fractal scattering by biological cells and subcellular structures,\" Opt. Lett. 32, 2324 2326 (2007) 27. M. Xu, \"Superposition rule for light scattering by a composite particle,\" Opt. Lett. 31, 3223 3225 (2006) 28. M. I. Mishchenko, L. D. Travis, and A. A. Lacis, Scattering, absorption, and emission of light by small particles (Cambridge University Press, Cambridge, UK, 2002) 29. W. J. Wiscombe, \"Improved Mie scattering algorithms,\" Appl. Opt. 19, 1505 1509 (1980) 30. The codes for the PPRM model, fitting procedures and the data can be found at http:/www.faculty.fairfield.edu/mxu. 31. A. N. Bashkatov, E. A. Genina, and V. V. Tuchin, \"Optical properties of skin, subcutaneous, and muscle tissues: a review,\" J. Innov. Opt. Health Sci. 04, 9 38 (2011) 32. P. J. Shaw, \"Nucleolus,\" in Encyclopedia of Life Sciences, (John Wiley Sons, Ltd. 2005) 33. H. A. Foster, D. K. Griffin, and J. M. Bridger, \"Interphase chromosome positioning in in vitro porcine cells and ex vivo porcine tissues,\" BMC Cell biol. 13, 30 (2012) 34. K. P. Nielsen, L. Zhao, J. J. Stamnes, K. Stamnes, and J. Moan, \"The importance of the depth distribution of melanin in skin for DNA protection and other photobiological processes,\" J. Photochem. Photobiol. B 82, 194 198 (2006) 35. V. G. Peters, D. R. Wyman, M. S. Patterson, and G. L. Frank, \"Optical properties of normal and diseased human breast tissues in the visible and near infrared,\" Phys. Med. Biol. 35, 1317 1334 (1990) 36. M. S. J. A. Malinowski, M. Peter Strokorb, M. Oesting, and K. Strokorb, \"Analysis, Simulation and Prediction of Multivariate Random Fields with Package {RandomFields}\" J. Stat. Software 63, 1 25 (2015) 37. X. Wang, \"Estimation of Scatterer Size and Number Density in Near Infrared Tomography,\" Ph.D. thesis, Dartmouth College (2007) 38. V. Nandakumar, L. Kelbauskas, K. F. Hernandez, K. M. Lintecum, P. Senechal, K. J. Bussey, P. C. W. Davies, R. H. Johnson, and D. R. Meldrum, \"Isotropic 3D nuclear morphometry of normal, fibrocystic and malignant breast epithelial cells reveals new structural alterations,\" PloS One 7, e29230 (2012) 39. L. F. Barbisan, J. Russo, and M. L. Mello, \"Nuclear and nucleolar image analysis of human breast epithelial cells transformed by benzo[a]pyrene and transfected with the c Ha ras oncogene,\" Anal. Cellular Path. 16, 193 199 (1998) 40. R. Drezek, A. Dunn, and R. Richards Kortum, \"A pulsed finite difference time domain (FDTD) method for calculating light scattering from biological cells over broad wavelength ranges,\" Opt. Express 6, 147 157 (2000) 41. R. S. Brock, X. H. Hu, D. A. Weidner, J. R. Mourant, and J. Q. Lu, \"Effect of detailed cell structure on light scattering distribution: FDTD study of a B cell with 3D structure constructed from confocal images,\" J. Quant. Spectr. Rad. Transfer 102, 25 36 (2006) 42. M. S. Starosta and A. K. Dunn, \"Three Dimensional Computation of Focused Beam Propagation through Multiple Biological Cells,\" Opt. Express 17, 12455 (2009) 43. H. K. Roy, Y. Liu, R. K. Wali, Y. L. Kim, A. K. Kromine, M. J. Goldberg, and V. Backman, \"Four dimensional elastic light scattering fingerprints as preneoplastic markers in the rat model of colon carcinogenesis,\" Gastroenterology 126, 1071 1081 (2004) 44. K. Badizadegan, V. Backman, C. W. Boone, C. P. Crum, R. R. Dasari, I. Georgakoudi, K. Keefe, K. Munger, S. M. Shapshay, E. E. Sheetse, and M. S. Feld, \"Spectroscopic diagnosis and imaging of invisible pre cancer,\" Faraday Discuss. 126, 265 279 (2004) 45. Y. Zhu, T. Fearn, G. Mackenzie, B. Clark, J. M. Dunn, I. J. Bigio, S. G. Bown, and L. B. Lovat, \"Elastic scattering spectroscopy for detection of cancer risk in Barrett's esophagus: experimental and clinical validation of error removal by orthogonal subtraction for increasing accuracy,\" J. Biomed. Opt. 14, 044022 (2010) 46. B. Delahunt, J. C. Cheville, G. Martignoni, P. A. Humphrey, C. Magi Galluzzi, J. McKenney, L. Egevad, F. Algaba, H. Moch, D. J. Grignon, R. Montironi, and J. R. Srigley, \"The International Society of Urological Pathology (ISUP) grading system for renal cell carcinoma and other prognostic parameters,\" Am. J. Surg. Path. 37, 1490 504 (2013) 47. M. I. Mishchenko, L. D. Travis, and", "author_names": [ "Xu Min" ], "corpus_id": 204959562, "doc_id": "204959562", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Plum pudding random medium model of biological tissue toward remote microscopy from spectroscopic light scattering", "venue": "", "year": 2014 } ]

[ { "abstract": "The ultrafast conversion of electrical signals to optical signals at the nanoscale is of fundamental interest for data processing, telecommunication and optical interconnects. However, the modulation bandwidths of semiconductor light emitting diodes are limited by the spontaneous recombination rate of electron hole pairs, and the footprint of electrically driven ultrafast lasers is too large for practical on chip integration. A metal insulator metal tunnel junction approaches the ultimate size limit of electronic devices and its operating speed is fundamentally limited only by the tunnelling time. Here, we study the conversion of electrons (localized in vertical gold hexagonal boron nitride gold tunnel junctions) to free space photons, mediated by resonant slot antennas. Optical antennas efficiently bridge the size mismatch between nanoscale volumes and far field radiation and strongly enhance the electron photon conversion efficiency. We achieve polarized, directional and resonantly enhanced light emission from inelastic electron tunnelling and establish a novel platform for studying the interaction of electrons with strongly localized electromagnetic fields.", "author_names": [ "Markus Parzefall", "Palash Bharadwaj", "A Jain", "Takashi Taniguchi", "K Watanabe", "Lukas Novotny" ], "corpus_id": 11726354, "doc_id": "11726354", "n_citations": 97, "n_key_citations": 2, "score": 1, "title": "Antenna coupled photon emission from hexagonal boron nitride tunnel junctions.", "venue": "Nature nanotechnology", "year": 2015 }, { "abstract": "We show that ordered monolayers of organic molecules stabilized by hydrogen bonding on the surface of exfoliated few layer hexagonal boron nitride (hBN) flakes may be incorporated into van der Waals heterostructures with integral few layer graphene contacts forming a molecu lar/2D hybrid tunneling diode. Electrons can tunnel from through the hBN/molecular barrier under an applied voltage VSD and we observe molecular electroluminescence from an excited singlet state with an emitted photon energy h eVSD, indicating up conversion by energies up to 1 eV. We show that tunnelling electrons excite emebedded molecules into singlet states in a two step process via an intermediate triplet state through inelastic scattering and also ob serve direct emission from the triplet state. These heterostructures provide a solid state device in which spin triplet states can be controllably excited and provide a new route to investigate the physics, chemistry and quantum spin based applications of triplet generation, emission and molecular photon up conversion.", "author_names": [ "Simon A Svatek", "James R Kerfoot", "Alex Summerfield", "Anton S Nizovtsev", "Vladimir V Korolkov", "Takashi Taniguchi", "Kenji Watanabe", "Elisa Antol'in", "Elena Besley", "Peter H Beton" ], "corpus_id": 202660970, "doc_id": "202660970", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Triplet excitation and electroluminescence from a supramolecular monolayer embedded in a boron nitride tunnel barrier.", "venue": "Nano letters", "year": 2019 }, { "abstract": "We show that ordered monolayers of organic molecules stabilized by hydrogen bonding on the surface of exfoliated few layer hexagonal boron nitride (hBN) flakes may be incorporated into van der Waals heterostructures with integral few layer graphene contacts forming a molecular/2D hybrid tunneling diode. Electrons can tunnel from through the hBN/molecular barrier under an applied voltage VSD and we observe molecular electroluminescence from an excited singlet state with an emitted photon energy eVSD, indicating up conversion by energies up to 1 eV. We show that tunnelling electrons excite embedded molecules into singlet states in a two step process via an intermediate triplet state through inelastic scattering and also observe direct emission from the triplet state. These heterostructures provide a solid state device in which spin triplet states, which cannot be generated by optical transitions, can be controllably excited and provide a new route to investigate the physics, chemistry and quantum spin based applications of triplet generation, emission and molecular photon up conversion.", "author_names": [ "Simon A Svatek", "James R Kerfoot", "Alex Summerfield", "Anton S Nizovtsev", "Vladimir V Korolkov", "Takashi Taniguchi", "Kenji Watanabe", "Elisa Antolin", "Elena Besley", "Peter H Beton" ], "corpus_id": 216566480, "doc_id": "216566480", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Triplet excitation and electroluminescence from a supramolecular monolayer embedded in a boron nitride tunnel barrier", "venue": "", "year": 2019 }, { "abstract": "We report on efficient carrier to exciton conversion and planar electroluminescence from tunnel diodes based on a metal insulator semiconductor (MIS) van der Waals heterostack consisting of few layer graphene (FLG) hexagonal boron nitride (hBN) and monolayer tungsten disulfide (WS2) These devices exhibit excitonic electroluminescence with extremely low threshold current density of a few pA*mm 2, which is several orders of magnitude lower compared to the previously reported values for the best planar EL devices. Using a reference dye, we estimate the EL quantum efficiency to be ~1% at low current density limit, which is of the same order of magnitude as photoluminescence quantum yield at the equivalent excitation rate. Our observations reveal that the efficiency of our devices is not limited by carrier to exciton conversion efficiency but by the inherent exciton to photon yield of the material. The device characteristics indicate that the light emission is triggered by injection of hot minority carriers (holes) to n doped WS2 by Fowler Nordheim tunneling and that hBN serves as an efficient hole transport and electron blocking layer. Our findings offer insight into the intelligent design of van der Waals heterostructures and avenues for realizing efficient excitonic devices.", "author_names": [ "Shunfeng Wang", "Junyong Wang", "Weijie Zhao", "Francesco Giustiniano", "Leiqiang Chu", "Ivan A Verzhbitskiy", "Justin Zhou Yong", "Goki Eda" ], "corpus_id": 206742732, "doc_id": "206742732", "n_citations": 47, "n_key_citations": 0, "score": 0, "title": "Efficient Carrier to Exciton Conversion in Field Emission Tunnel Diodes Based on MIS Type van der Waals Heterostack.", "venue": "Nano letters", "year": 2017 }, { "abstract": "Layered materials (LM) and their heterostructures (LMH) provide a promising platform for applications in photonics and electronics [1] such as tunneling junctions [2] photodetectors [3] and light emitting diodes (LEDs) [4] LEDs based on LM exploit the direct bandgap of semiconducting monolayer transition metal dichalcogenides (1L TMDs) [5] A key parameter to define the performances of LEDs is the external quantum efficiency (EQE) i.e. the ratio between emitted photons and injected electrons. Thus far, the EQE in LEDs based on LMH reached values ~0.2%[6] Here, we fabricate LEDs via vertically stacking singlelayer graphene (SLG) used as a transparent electrode for charge injection, few layer hexagonal boron nitride (hBN) used as a tunnel barrier, and a 1L TMDs (MoS2, WS2, WSe2) for light emission (Fig. 1) We measure the tunneling current, Fig. 2a, and electroluminescence, Fig. 2b. We show that a chemical treatment using the superacid bis(trifluoromethane)sulfonimide (TFSI) enhances by more than four times the EQE in LMH based LEDs, up to 1% (Fig. 2) We present simulations and modeling of integration of LMH LEDs with photonic cavities for further enhancement of EQE. This approach paves the way to highly efficient LEDs. References", "author_names": [ "Domenico De Fazio", "Ioannis Paradisanos", "", "Takashi Taniguchi", "Giancarlo Soavi", "Elefterios Lidorikis", "Ilya Goykhman", "Andrea C Ferrari" ], "corpus_id": 189799591, "doc_id": "189799591", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Graphene 2019 June 25 28 2019 Rome Italy Light Emitting Diodes Based on Layered Heterostructures on Photonic Cavities", "venue": "", "year": 2019 }, { "abstract": "The understanding of and control over light emission from quantum tunneling has challenged researchers for more than four decades due to the intricate interplay of electrical and optical properties in atomic scale volumes. Here we introduce a device architecture that allows for the disentanglement of electronic and photonic pathways van der Waals quantum tunneling devices. The electronic properties are defined by a stack of two dimensional atomic crystals whereas the optical properties are controlled via an external photonic architecture. In van der Waals heterostructures made of gold, hexagonal boron nitride and graphene we find that inelastic tunneling results in the emission of photons and surface plasmon polaritons. By coupling these heterostructures to optical nanocube antennas we achieve resonant enhancement of the photon emission rate in narrow frequency bands by four orders of magnitude. Our results lead the way towards a new generation of nanophotonic devices that are driven by quantum tunneling.Electrical and optical properties of light emitting devices driven by quantum tunneling are closely intertwined. Parzefall et al. show that these properties can be individually controlled by cointegrating van der Waals heterostructures with optical antennas.", "author_names": [ "Markus Parzefall", "Aron Szabo", "Takashi Taniguchi", "Kenji Watanabe", "Mathieu Luisier", "Lukas Novotny" ], "corpus_id": 58014769, "doc_id": "58014769", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Light from van der Waals quantum tunneling devices", "venue": "Nature Communications", "year": 2019 }, { "abstract": "Two dimensional (2 D) hexagonal boron nitride (h BN) has attracted considerable attention for deep ultraviolet optoelectronics and visible single photon sources, however, realization of an electrically driven light emitter remains challenging due to its wide bandgap nature. Here, we report electrically driven visible light emission with a red shift under increasing electric field from a few layer h BN by employing a five period Al2O3/h BN multiple heterostructure and a graphene top electrode. Investigation of electrical properties reveals that the Al2O3 layers act as potential barriers confining injected carriers within the h BN wells, while suppressing the electrostatic breakdown by trap assisted tunneling, to increase the probability of radiative recombination. The result highlights a promising potential of such multiple heterostructure as a practical and efficient platform for electrically driven light emitters based on wide bandgap two dimensional materials.", "author_names": [ "Seunghee Lee", "Hokyeong Jeong", "Dong Yeong Kim", "Seung-Young Seo", "Cheolhee Han", "Odongo Francis Ngome Okello", "J I Lo", "Yu-Chain Peng", "Chan-Hyoung Oh", "Gyeong Won Lee", "Jong-In Shim", "Bing-Ming Cheng", "Kyung Song", "Sihyuk Choi", "Moon-Ho Jo", "Jong Kyu Kim" ], "corpus_id": 198454375, "doc_id": "198454375", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Electroluminescence from h BN by using Al2O3/h BN multiple heterostructure.", "venue": "Optics express", "year": 2019 }, { "abstract": "Single defects in monolayer WSe2 have been shown to be a new class of single photon emitters and have potential applications in quantum technologies. Whereas previous work relied on optical excitation of single defects in isolated WSe2 monolayers, in this work we demonstrate electrically driven single defect light emission by using both vertical and lateral van der Waals heterostructure devices. In both device geometries, we use few layer graphene as the source and drain and hexagonal boron nitride as the dielectric spacer layers for engineered tunneling contacts. In addition, the lateral devices utilize a split back gate design to realize an electrostatically defined p i n junction. At low current densities and low temperatures ~5 K) we observe narrow spectral lines in the electroluminescence (EL) whose properties are consistent with optically excited defect bound excitons. We show that the emission originates from spatially localized regions of the sample, and the EL spectrum from single defects has a doublet with the characteristic exchange splitting and linearly polarized selection rules. All are consistent with previously reported single photon emitters in optical measurements. Our results pave the way for on chip and electrically driven single photon sources in two dimensional semiconductors for quantum technology applications.", "author_names": [ "Genevieve Clark", "John R Schaibley", "Jason S Ross", "Takashi Taniguchi", "Kenji Watanabe", "Joshua R Hendrickson", "Shin Mou", "Wang Yao", "Xiaodong Xu" ], "corpus_id": 206734963, "doc_id": "206734963", "n_citations": 83, "n_key_citations": 0, "score": 0, "title": "Single Defect Light Emitting Diode in a van der Waals Heterostructure.", "venue": "Nano letters", "year": 2016 }, { "abstract": "Description", "author_names": [ "Tiancheng Song", "Eric Anderson", "Matisse Wei-Yuan Tu", "Kyle L Seyler", "Takashi Taniguchi", "Kenji Watanabe", "Michael A McGuire", "Xiaosong Li", "Ting Cao", "Di Xiao", "Wang Yao", "Xiaodong Xu" ], "corpus_id": 231986578, "doc_id": "231986578", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Spin photovoltaic effect in magnetic van der Waals heterostructures", "venue": "Science advances", "year": 2021 }, { "abstract": "Light emitting diodes are of importance for lighting, displays, optical interconnects, logic and sensors. Hence the development of new systems that allow improvements in their efficiency, spectral properties, compactness and integrability could have significant ramifications. Monolayer transition metal dichalcogenides have recently emerged as interesting candidates for optoelectronic applications due to their unique optical properties. Electroluminescence has already been observed from monolayer MoS2 devices. However, the electroluminescence efficiency was low and the linewidth broad due both to the poor optical quality of MoS2 and to ineffective contacts. Here, we report electroluminescence from lateral p n junctions in monolayer WSe2 induced electrostatically using a thin boron nitride support as a dielectric layer with multiple metal gates beneath. This structure allows effective injection of electrons and holes, and combined with the high optical quality of WSe2 it yields bright electroluminescence with 1000 times smaller injection current and 10 times smaller linewidth than in MoS2. Furthermore, by increasing the injection bias we can tune the electroluminescence between regimes of impurity bound, charged, and neutral excitons. This system has the required ingredients for new kinds of optoelectronic devices such as spinand valley polarized light emitting diodes, on chip lasers, and two dimensional electro optic modulators. Main Text Few layer group VIB transition metal dichalcogenides (TMDs) represent a class of semiconductors in the two dimensional (2D) limit. Due to their large carrier effective mass and the reduced screening in 2D, electron hole interactions are much stronger than in conventional semiconductors. This leads to large binding energies for both charged and neutral excitons which as a result are spectrally sharp, robust, and amenable to electrical manipulation. In addition, the large spin orbit coupling and the acentric structure of TMDs provides a connection between spin and valley degrees of freedom, light polarization, and magnetic and electric fields that can be exploited for new kinds of device operation. Although in bulk TMDs the band gap is indirect, in the limit of a single monolayer it becomes direct, fulfilling the most basic requirement for efficient light emission. Indeed, electroluminescence (EL) has already been reported from monolayer MoS2 field effect transistors (FETs) occurring near the Schottky contact with a metal or with highly doped silicon. However, the efficiency and spectral quality was much lower than has been demonstrated for other nanoscale light emitters such as carbon nanotubes, for two reasons. First, efficient EL requires effective injection of both electrons and holes into the active region, which should therefore be within a p n junction. Second, MoS2 is known to have poorer optical quality than other group VIB TMDs, possibly due to impurities. It has been previously shown that in contrast monolayer WSe2 has excellent optical properties. Here, we demonstrate that combining monolayer WSe2 with a p n junction architecture using electrostatic doping produces efficient and electrically tunable excitonic light emitting diodes (LEDs) An optical image and a schematic of a device, made by a combination of electron beam lithography and transfer of exfoliated sheets, are shown Figs. 1a and 1b. A monolayer WSe2 sheet sits on a sheet of hexagonal boron nitride (BN) typically 10 nm thick, which acts both as a smooth, disorder free substrate to minimize non radiative energy relaxation pathways and as a high quality gate dielectric. Applying voltages to the two 7 nm palladium gate electrodes beneath the BN can create two separate electrostatically doped regions in the WSe2 separated by a 300 nm wide undoped strip. Gold/vanadium (60/6 nm) source and drain contacts are evaporated on top. Importantly, they overlap the gates in order to reduce the Schottky barriers at the contacts. For electrical transport measurements a dc bias is applied to one contact (the source) and the current from the other (the drain) is measured by a virtual earth current preamplifier. The silicon substrate is grounded. We start by showing that a p n junction can be created electrostatically. First we set the gate voltages Vg1 and Vg2 to the same value. Figure 1c shows the current produced by a bias V 0.5 V as the gate voltage Vg1 Vg2 is swept at 60 K (room temperature measurements are shown in Supplementary Figure 1) The current increases rapidly for gate voltages +6.5 V (electron doping) and 6.5 V (hole doping) demonstrating ambipolar operation. In the inset the red I V curve, taken at Vg1 Vg2 +8.0 V, is almost symmetric as expected for both gated regions being equally electron doped. The nonlinearity near zero bias can be associated with the undoped gap between the gates and residual Schottky barriers at the contacts. In contrast, the blue I V curve, taken with Vg1 +8.0 V and Vg2 8.0 V, shows the strong rectification behavior expected for a p n junction. The p n junction can be investigated in detail by scanning optical measurements. Fig. 2a is a microscope image of a device and Fig. 2b is a corresponding scanning photocurrent image, measured with zero bias at 100 K using a 10 mW diffraction limited 660 nm laser spot scanned over the sample. We see a large photocurrent signal localized between the gates, with a peak magnitude of 5 nA. Taking into account the 1% absorption of WSe2 monolayers at 660 nm, the internal quantum efficiency reaches a maximum of about 5% Such a photocurrent is the natural result of the junction functioning as a photodiode, with photogenerated carriers separated by a strong depletion field concentrated in the undoped gap. The sensitivity of the photodiode can be tuned over a wide range by varying the gate voltages and bias (see Supplemental Figure 2) Fig. 2c is a corresponding map of the integrated photoluminescence (PL) intensity, which indicates the high optical quality of the whole WSe2 sheet and shows that the luminescence is not substantially quenched by the underlying gates. More revealingly, Fig. 2d shows a colour map of the peak PL photon energy, exhibiting two distinct regions clearly correlated with the expected ndoped (blue) and p doped (red) parts of the WSe2 above the gates. The reason for this is made clear in Fig. 2e, which shows PL spectra taken at different positions. The detailed origin of these spectral features has been established previously. Above the gate held at Vg1 +8.0 V (blue trace) the negatively charged X trion (two electrons and one hole) dominates, implying an excess of electrons. Above the other gate, held at Vg2 8.0 V (red trace) the higher energy positively charged X trion (two holes and one electron) dominates, implying an excess of holes. In the gap between the gates (black trace) the neutral exciton X peak can also be seen, consistent with no doping in that region. Here the superimposed X and X peaks may come from the gated regions, since the laser spot is larger than the gap. When the device is configured as a p n junction (Vg1 Vg2 8 V) but not otherwise, we observe bright electroluminescence. Good spectra can be obtained even at room temperature with a current of 5 nA, as illustrated (blue) in Fig. 3a. This current is three orders of magnitude smaller than in MoS2 FETs. In fact, in our best device we observed EL at an injection current as low as 200 pA (See Supplemental Figure 3) To understand the nature of the EL, we superimpose a normalized PL spectrum of undoped monolayer WSe2 (red) It is known that the PL of WSe2 is from the recombination of direct gap excitons; thus the similarity between the EL and PL spectra implies that the injected electrons and holes form excitons before recombining radiatively. This is a natural consequence of the large exciton binding energy due to the strong Coulomb interaction in monolayer TMDs. Fig. 3b shows an image of the total EL intensity (coloured) superimposed on a simple white light reflection image (grayscale) It is clear that the EL emanates from the entire length of the monolayer junction between the two gates. At low temperatures the EL spectrum develops interesting structure. Fig. 4a shows a plot of EL intensity as a function of current and photon energy. There are three main spectral features: a narrow higher energy peak (green arrow) a broad central peak (brown arrow) and a lower energy peak (black arrow) The shapes and relative intensities of these features change with current. Their origins can be deduced from a comparison with the PL, whose intensity is plotted in Fig. 4b as a function of photon energy and common gate voltage Vg=Vg1=Vg2. Here we see the tuning of the dominant exciton species as the carrier density is changed by gating. The PL feature which is strongest at Vg 0 is due to X recombination. It has a similar width to, and is at the same position (1.69 eV) as, the narrow EL peak, which we therefore identify as the X emission. The dominant PL feature at Vg 0, which shifts from 1.663 eV to 1.625 eV as Vg increases from 0 to +8 V, is due to X (of which there are multiple species) The broad EL feature occurs in the same range of energies, implying that it is dominated by X. The dominant feature in the PL at Vg 0 is due to X. This aligns with the high energy shoulder (grey arrow) on the broad EL feature at about 1.670 eV. There is also a band of emission from impurity bound excitons (X) in the PL which matches the lower energy EL feature centered at 1.59 eV. The finding that X dominates the EL in Fig. 4a is consistent with the observation that X has much stronger PL than the other exciton species (Fig. 4b) The shifts of the trion peaks in the PL with Vg imply that the trion binding energy depends on perpendicular electric field. Hence the fact that the width of the broad peak in the EL matches the full range of X energies in the P", "author_names": [ "Jason S Ross", "Philip Klement", "Aaron M Jones", "Nirmal J Ghimire", "", "David G Mandrus", "Takashi Taniguchi", "Kenji Watanabe", "Kenji Kitamura", "Wang Yao", "David H Cobden", "Xiaodong Xu" ], "corpus_id": 28245833, "doc_id": "28245833", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Title: Electrically Tunable Excitonic Light Emitting Diodes based on Monolayer WSe2 p n Junctions", "venue": "", "year": 2014 } ]

[ { "abstract": "Metal@dielectric composite nanostructures are of high demand for their vast technological applications. The Stober method, either in its original form or by modification, has been utilized for the fabrication of silica shells over metal, semiconductor, or even dielectric nanostructures, with the aim to protect them from degradation, enhance their biocompatibility, or use them for molecular anchoring. However, the stability of silica shells and the dispersion of core shell nanostructures remain the main limitations for their efficient applications. Here we demonstrate that utilization of ultrasound during hydrolysis and condensation of the metal organic silicon precursor in Stober process can produce stable and uniform silica shell layers around gold nanoparticles, enhancing both their stability and dispersion. Through transmission electron microscopy and infrared spectroscopy techniques, we demonstrate that the Au@SiO2 nanoparticles fabricated with ultrasound treatment during silica shell growth contain a.", "author_names": [ "Jose Luis Montano-Priede", "Joao Paulo Coelho", "Andres Guerrero-Martinez", "Ovidio Pena-Rodriguez", "Umapada Pal" ], "corpus_id": 102478290, "doc_id": "102478290", "n_citations": 38, "n_key_citations": 1, "score": 1, "title": "Fabrication of Monodispersed Au@SiO2 Nanoparticles with Highly Stable Silica Layers by Ultrasound Assisted Stober Method", "venue": "", "year": 2017 }, { "abstract": "Abstract A system of chemical reactions has been developed which permits the controlled growth of spherical silica particles of uniform size by means of hydrolysis of alkyl silicates and subsequent condensation of silicic acid in alcoholic solutions. Ammonia is used as a morphological catalyst. Particle sizes obtained in suspension range from less than 0.05 m to 2 m in diameter.", "author_names": [ "Werner Stober", "Arthur I Fink", "Ernst Bohn" ], "corpus_id": 98200282, "doc_id": "98200282", "n_citations": 10223, "n_key_citations": 98, "score": 0, "title": "Controlled growth of monodisperse silica spheres in the micron size range", "venue": "", "year": 1968 }, { "abstract": "Colloidal hollow mesoporous silica nanoparticles (HMSNs) are aspecial type of silica based nanomaterials with penetrating mesopore channels on their shells. HMSNs exhibit unique structural characteristics useful for diverse applications: Firstly, the hollow interiors can function as reservoirs for enhanced loading of guest molecules, or as nanoreactors for the growth of nanocrystals or for catalysis in confined spaces. Secondly, the mesoporous silica shell enables the free diffusion of guest molecules through the intact shell. Thirdly, the outer silica surface is ready for chemical modifications, typically via its abundant Si OH bonds. As early as 2003, researchers developed a soft templating methodto prepare hollow aluminosilicate spheres with penetrating mesopores in a cubic symmetry pattern on the shells. However, adapting this method for applications on the nanoscale, especially for biomedicine, has proved difficult because the soft templating micelles are very sensitive to liquid environments, making it difficult to tune key parameters such as dispersity, morphology and structure. In this Account, we present the most recent developments in the tailored construction of highly dispersive and monosized HMSNs using simple silica etching chemistry, and we discuss these particles' excellent performance in diverse applications. We first introduce general principles of silica etching chemistry for controlling the chemical composition and the structural parameters (particle size, pore size, etching modalities, yolk shell nanostructures, etc. of HMSNs. Secondly, we include recent progress in constructing heterogeneous, multifunctional, hollow mesoporous silica nanorattles via several methods for diverse applications. These elaborately designed HMSNs could be topologically transformed to prepare hollow mesoporous carbon nanoparticles or functionalized to produce HMSN based composite nanomaterials. Especially in biomedicine, HMSNs are excellent as carriers to deliver either hydrophilic or hydrophobic anti cancer drugs, to tumor cells, offering enhanced chemotherapeutic efficacy and diminished toxic side effects. Most recently, research has shown that loading one or more anticancer drugs into HMSNs can inhibit metastasis or reverse multidrug resistance of cancer cells. HMSNs could also deliver hydrophobic perfluorohexane (PFH) molecules to improve high intensity focused ultrasound (HIFU) cancer surgery by changing the tissue acoustic environment; and HMSNs could act as nanoreactors for enhanced catalytic activity and/or durability. The versatility of silica etching chemistry, a simple but scalable synthetic methodology, offers great potential for the creation of new types of HMSN based nanostructures in a range of applications.", "author_names": [ "Yu Chen", "Hang Chen", "Jian Lin Shi" ], "corpus_id": 12349656, "doc_id": "12349656", "n_citations": 240, "n_key_citations": 0, "score": 0, "title": "Construction of homogenous/heterogeneous hollow mesoporous silica nanostructures by silica etching chemistry: principles, synthesis, and applications.", "venue": "Accounts of chemical research", "year": 2014 }, { "abstract": "We investigate the dependence of the center of mass tomogram of a system with many degrees of freedom $N$ on the Planck constant \\hbar It is shown that to use the central limit theorem under taking the limit $N\\to \\infty one should keep the energy of the system to be constant. In the case, the resulting distribution is Gaussian if the initial distribution is a product of independent excited states of a quantum oscillator or even and odd coherent states either. Then, if one turns the Planck constant \\hbar \\to 0$ we get \\delta function associated with the distribution concentrated in zero with the probability equal to one.", "author_names": [ "Grigori G Amosov", "Vladimir I Man'ko" ], "corpus_id": 18098126, "doc_id": "18098126", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A use of the central limit theorem to obtain a classical limit for the center of mass tomogram", "venue": "", "year": 2009 }, { "abstract": "Although humans have been exposed to airborne nanosized particles (NSPs; 100 nm) throughout their evolutionary stages, such exposure has increased dramatically over the last century due to anthropogenic sources. The rapidly developing field of nanotechnology is likely to become yet another source through inhalation, ingestion, skin uptake, and injection of engineered nanomaterials. Information about safety and potential hazards is urgently needed. Results of older bio kinetic studies with NSPs and newer epidemiologic and toxicologic studies with airborne ultrafine particles can be viewed as the basis for the expanding field of nanotoxicology, which can be defined as safety evaluation of engineered nanostructures and nanodevices. Collectively, some emerging concepts of nanotoxicology can be identified from the results of these studies. When inhaled, specific sizes of NSPs are efficiently deposited by diffusional mechanisms in all regions of the respiratory tract. The small size facilitates uptake into cells and transcytosis across epithelial and endothelial cells into the blood and lymph circulation to reach potentially sensitive target sites such as bone marrow, lymph nodes, spleen, and heart. Access to the central nervous system and ganglia via translocation along axons and dendrites of neurons has also been observed. NSPs penetrating the skin distribute via uptake into lymphatic channels. Endocytosis and biokinetics are largely dependent on NSP surface chemistry (coating) and in vivo surface modifications. The greater surface area per mass compared with larger sized particles of the same chemistry renders NSPs more active biologically. This activity includes a potential for inflammatory and pro oxidant, but also antioxidant, activity, which can explain early findings showing mixed results in terms of toxicity of NSPs to environmentally relevant species. Evidence of mitochondrial distribution and oxidative stress response after NSP endocytosis points to a need for basic research on their interactions with subcellular structures. Additional considerations for assessing safety of engineered NSPs include careful selections of appropriate and relevant doses/concentrations, the likelihood of increased effects in a compromised organism, and also the benefits of possible desirable effects. An interdisciplinary team approach (e.g. toxicology, materials science, medicine, molecular biology, and bioinformatics, to name a few) is mandatory for nanotoxicology research to arrive at an appropriate risk assessment.", "author_names": [ "Gunter Oberdorster", "Eva Oberdorster", "Jan Oberdorster" ], "corpus_id": 10982689, "doc_id": "10982689", "n_citations": 6601, "n_key_citations": 371, "score": 0, "title": "Nanotoxicology: An Emerging Discipline Evolving from Studies of Ultrafine Particles", "venue": "Environmental health perspectives", "year": 2005 }, { "abstract": "Colloidal nanoparticles composed out of a 4 nm monodisperse, radioactively labelled gold core (198Au) and a radioactively labelled polymer shell (111In) were administered via intravenous injection to rats. These nanoparticles have excellent colloidal stability in vitro. Independent biodistribution data obtained from the 198Au and 111In labels indicate that in vivo the polymer shell comes at least partially off the nanoparticle core. This demonstrates that even high quality nanoparticles with well defined colloidal properties in vitro, can radically change their physicochemical properties in in vivo scenarios. Additional \"in test tube\" and in vitro data suggest that degradation of the polymer shell may be caused by proteolytic enzymes. Thus physicochemical characterization as performed of the nanoparticles in media outside cells has to be considered to apply only partly for internalized nanoparticles.", "author_names": [ "Abuelmagd M Abdelmonem" ], "corpus_id": 102649035, "doc_id": "102649035", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Nanoparticles: Synthesis, Surface Modification and Functionalization for Biological and Environmental Applications", "venue": "", "year": 2014 }, { "abstract": "In order to selectively target malignant cells and eliminate severe side effects of conventional chemotherapy, biocompatible and redox responsive hollow nanocontainers with tumor specificity were fabricated. The mechanized nanocontainers were achieved by anchoring mechanically interlocked molecules, i.e. [2]rotaxanes, onto the orifices of hollow mesoporous silica nanoparticles via disulfide bonds as intermediate linkers for intracellular glutathione triggered drug release. The [2]rotaxane employed was mainly composed of U.S. Food and Drug Administration approved tetraethylene glycol chains, a cyclodextrin, and folic acid. In this study, folate groups on the mechanized hollow nanocontainers act as both the tumor targeting agents and stoppers of the [2]rotaxanes. Detailed investigations showed that anticancer drug doxorubicin loaded mechanized nanocontainers could selectively induce the apoptosis and death of tumor cells. The drug loaded nanocontainers enhanced the targeting capability to tumor tissues in vitro and inhibited the tumor growth with minimal side effects in vivo. The present controlled and targeted drug delivery system paves the way for developing the next generation of nanotherapeutics toward efficient cancer treatment.", "author_names": [ "Zhong Luo", "Xingwei Ding", "Yan Hu", "Shaojue Wu", "Yang Xiang", "Yongfei Zeng", "Beilu Zhang", "Hong Yan", "Huacheng Zhang", "Liangliang Zhu", "Junjie Liu", "Jinghua Li", "Kaiyong Cai", "Yanli Zhao" ], "corpus_id": 1153997, "doc_id": "1153997", "n_citations": 183, "n_key_citations": 5, "score": 0, "title": "Engineering a hollow nanocontainer platform with multifunctional molecular machines for tumor targeted therapy in vitro and in vivo.", "venue": "ACS nano", "year": 2013 }, { "abstract": "Semiconducting quantum dots, whose particle sizes are in the nanometer range, have very unusual properties. The quantum dots have band gaps that depend in a complicated fashion upon a number of factors, described in the article. Processing structure properties performance relationships are reviewed for compound semiconducting quantum dots. Various methods for synthesizing these quantum dots are discussed, as well as their resulting properties. Quantum states and confinement of their excitons may shift their optical absorption and emission energies. Such effects are important for tuning their luminescence stimulated by photons (photoluminescence) or electric field (electroluminescence) In this article, decoupling of quantum effects on excitation and emission are described, along with the use of quantum dots as sensitizers in phosphors. In addition, we reviewed the multimodal applications of quantum dots, including in electroluminescence device, solar cell and biological imaging.", "author_names": [ "Debasis Bera", "Lei Qian", "Teng-Kuan Tseng", "Paul H Holloway" ], "corpus_id": 18357200, "doc_id": "18357200", "n_citations": 692, "n_key_citations": 17, "score": 0, "title": "Quantum Dots and Their Multimodal Applications: A Review", "venue": "Materials", "year": 2010 }, { "abstract": "Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004 2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930 2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed. Copyright (c) 2014 John Wiley Sons, Ltd.", "author_names": [ "Michael J Whitcombe", "Nicole Kirsch", "Ian A Nicholls" ], "corpus_id": 206095130, "doc_id": "206095130", "n_citations": 323, "n_key_citations": 2, "score": 0, "title": "Molecular imprinting science and technology: a survey of the literature for the years 2004 2011", "venue": "Journal of molecular recognition JMR", "year": 2014 }, { "abstract": "We gratefully acknowledge funding and support from King Abdullah University of Science and Technology (KAUST) Thanks are also due to the KAUST communication department for designing several images for this Review.", "author_names": [ "Vivek Polshettiwar", "Rafael Luque", "Aziz Fihri", "Haibo Zhu", "Mohamed Bouhrara", "Jean-Marie Basset" ], "corpus_id": 206894302, "doc_id": "206894302", "n_citations": 1252, "n_key_citations": 2, "score": 0, "title": "Magnetically recoverable nanocatalysts.", "venue": "Chemical reviews", "year": 2011 } ]

[ { "abstract": "Multi level topologies reduce the requirements on inductors and filters, however, given the high number of series connected semiconductors, it is still unclear if they are a suitable option to achieve ultra high efficiency while maintaining a reasonable power density. For this purpose, an extensive quantitative evaluation of different topologies is carried out, to determine the required volume for a targeted 99.5% efficiency of a 10kW three phase inverter. This includes the EMI noise filtering, where the Common Mode filter is placed on the DC side to save losses and the impact of the upcoming EMI regulations covering the range from 2 kHz to 150 kHz is discussed. With an evaluation of multilevel topologies, it is shown that even if a high number of levels can reduce the size of the magnetic components by an order of magnitude, the volume and losses of the capacitive components required to create the multi level voltage output have to be considered. An evaluation is done to quantify the performance of topologies ranging from two level to seven level topologies, and detailed designs of the three level T type and seven level Hybrid Active Neutral Point Clamped converters are presented, achieving a relatively high power density of 2.2 kW/dm3 and 2.7 kW/dm3 respectively.", "author_names": [ "Jon Azurza Anderson", "Lukas Schrittwieser", "Michael Leibl", "Johann Walter Kolar" ], "corpus_id": 38992342, "doc_id": "38992342", "n_citations": 9, "n_key_citations": 2, "score": 1, "title": "Multi level topology evaluation for ultra efficient three phase inverters", "venue": "2017 IEEE International Telecommunications Energy Conference (INTELEC)", "year": 2017 }, { "abstract": "A more suitable model of multi level inverter with fault tolerant ability is studied and analyzed in this paper. Here, an accurate comparative evaluation can adduce evidence of the multi level inverter with the traditional cascade inverter for solar water pumping systems is conferred. The modified multilevel inverter which is proposed helps in minimizing the number of gate drivers and switch count compared to other genre of multilevel inverters. A level shifted multi carrier PWM is the technique used for the proposed system. For the meticulous analysis, the suggested five level and the present 5 level inverters are built using MATLAB platform. And naturally the topology that has been designed accomplished well while in comparison to the conventional. In order to state the feasibility of the recommendeda simulation analysis is accomplished and varied results are presented.", "author_names": [ "M Narasimha Rao", "N K Karthick", "A Madhukar Rao" ], "corpus_id": 232413631, "doc_id": "232413631", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fault Tolerant Ability of A Multi Level Inverter Fed Three Phase Induction Motor for Water Pumping Application", "venue": "2021 7th International Conference on Electrical Energy Systems (ICEES)", "year": 2021 }, { "abstract": "In recent years, multilevel inverters are becoming more popular for high power and high voltage application. Due to their improved harmonic profile and increased power ratings. Many studies have been reported in the literature on multilevel inverters topologies, control techniques, and applications. However, there are few studies that actually discuss or evaluate the performance of induction motor drives associated with three phase multilevel inverter. This paper presents a comparison study for a cascaded Hbridge multilevel direct torque control (DTC) induction motor drive. In this case, symmetrical and asymmetrical arrangements of fiveand seven level Hbridge inverters are compared in order to find an optimum arrangement with lower switching losses and optimized output voltage quality. Simulation results are proposed by using MATLAB/SIMULINK model.", "author_names": [ "Lanka Srinu", "M Kondalu", "Ganta Naveen", "A Pavan Kumar" ], "corpus_id": 212583519, "doc_id": "212583519", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "COMPARISON STUDY OF THREE PHASE CASCADED H BRIDGE MULTI LEVEL INVERTER BY USING DTC INDUCTION MOTOR DRIVES", "venue": "", "year": 2014 }, { "abstract": "This paper proposes a new PWM generation scheme for the three phase five level cascaded multilevel inverter. The main objective of this paper to improve the power quality by using various multi carrier PWM methods. Generally multi carrier based methods have been used widely for switching of multilevel inverters due to their simplicity, flexibility and reduced computational requirements compared to Space Vector Modulation (SVM) techniques. Several multi carrier modulation methods with miscellaneous properties have been already known. While evaluating and comparing these methods, such as PD, POD and APOD through measures like total harmonic distortion (THD) the paper shows their advantages for applications of Cascade multi level topologies by simulation results. Finally simulation results and experimental results are discussed.", "author_names": [ "P V Vivek", "J Nanda Gopal", "V Vignesh", "T Vigneshwaran" ], "corpus_id": 30679270, "doc_id": "30679270", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A novel approach on power quality improvement by multi carrier multilevel inverter topology", "venue": "2016 3rd International Conference on Electrical Energy Systems (ICEES)", "year": 2016 }, { "abstract": "Latest research results on three phase wide bandgap (WBG) inverter systems with full sinewave output voltage filtering are reported. A new soft switching modulation scheme for two level 1200 V SiC inverters is described. Furthermore, a new Figure of Merit for determining maximum multi level (ML) bridge leg efficiency is defined and low voltage GaN devices are evaluated considering ML flying capacitor (FC) and multi cell inverter structures. Finally, new integrated filter buck boost current DC link inverter topologies are discussed.", "author_names": [ "Johann Walter Kolar", "Jon Azurza Anderson", "Spasoje Miric", "Michael Haider", "Mattia Guacci", "Michael Antivachis", "Grayson D Zulauf", "David Menzi", "Pascal S Niklaus", "Johann Minibock", "Panteleimon Papamanolis", "Gwendolin Rohner", "Neha Nain", "Davide Cittanti", "Dominik Bortis" ], "corpus_id": 232266287, "doc_id": "232266287", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Application of WBG Power Devices in Future 3 Ph Variable Speed Drive Inverter Systems \"How to Handle a Double Edged Sword\"", "venue": "2020 IEEE International Electron Devices Meeting (IEDM)", "year": 2020 }, { "abstract": "This paper presents a comprehensive analysis of the 5 phase induction motor driven by voltage source inverter drives and particularly its steady state performance evaluation. The performance of various modulation methods are analyzed with insightful look into their harmonic content and torque ripple. Three separate methods are proposed to reduce the torque ripple for low, middle and high modulation index regions while eliminating or controlling the non torque producing harmonics within the current machine rating. A complete set of simulations are carried out to verify the concepts and proposed methods. The multi level multiphase topology is introduced and it is compared to the two level system. The modification of switching sequence for reduction of torque ripple is applied to the three level 5 phase motor drive. Application of the multilevel multi phase concept to high power motor drives (as well as motor design and selection) is discussed.", "author_names": [ "Shuai Lu", "Keith A Corzine" ], "corpus_id": 44408816, "doc_id": "44408816", "n_citations": 75, "n_key_citations": 1, "score": 0, "title": "Multilevel multi phase propulsion drives", "venue": "IEEE Electric Ship Technologies Symposium, 2005.", "year": 2005 }, { "abstract": "The multi level inverter system is habitually exploited in AC drives, when both reduced harmonic contents and high power are required. In this paper, a new topology for three phase asymmetrical multilevel inverter employing reduced number of switches is introduced. With less number of switches, the cost, space and weight of the circuit are automatically reduced. This paper discusses the new topology, the switching strategies and the operational principles of the chosen inverter. Simulation is carried out using MATLAB SIMULINK. Various conventional PWM techniques that are appropriate to the chosen circuit such as PDPWM, PODPWM, APODPWM, VFPWM and COPWM are employed in this work. COPWM technique affords the less THD value and also affords a higher fundamental RMS output voltage.", "author_names": [ "Chinnapettai Ramalingam Balamurugan", "Sirukarumbur Pandurangan Natarajan", "T S Anandhi" ], "corpus_id": 3531550, "doc_id": "3531550", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Performance Evaluation of 3Ph Asymmetrical MLI with Reduced Switch Count", "venue": "", "year": 2016 }, { "abstract": "Multilevel inverters have received more attentions their considerable advantages such as high power quality, lower harmonic components, better electro magnetic consistence, lower dv/dt and lower switching losses. Lot of research was going on multi level inverter topologies and many researchers are proposed so many multi level inverter topologies. This paper proposes a robust adaptive voltage control of three phase voltage source inverter for a distributed generation system in a standalone operation. The proposed adaptive voltage control technique combines an adaption control term and a state feedback control term. The proposed algorithm is easy to implement, but it is very robust to system uncertainties and sudden load disturbances. With the proposed system, we can achieve fast transient response, zero steady state error, and low THD.Mathematical modeling and simulation studies using Simpower systems Block set of MATLAB are proposed. Switching scheme for the proposed converter circuit is designed with the help of sinusoidal pulse width modulation scheme. Total Harmonic distortion in the output voltage is evaluated using FFT tool of MATLAB SIMULINK. Keywords: Adaptive voltage control; distributed generation system (DGS) robust control; stability analysis; standalone operation; uncertainties; voltage source inverter.", "author_names": [ "Valluri Chandra Sekhar", "S Raj Shekar" ], "corpus_id": 55275199, "doc_id": "55275199", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Adaptive Voltage Control of a 3 Phase Inverter for a Standalone Distributed Generation", "venue": "", "year": 2016 }, { "abstract": "In this paper a new three phase, five level inverter topology with a single dc source Multi level inverter based Dynamic Voltage Restorer (DVR) is presented to improve the Power quality in distribution system by injecting voltage in series for the protection of sensitive loads against voltage sags and voltage swells. The performance of the DVR depends on control technique involved .In this paper fuzzy logic controller is used to control the injection of voltage when the fault occurs. Among the Power quality issues voltage sags and voltage Swells are major problems which are concentrated in this paper. The DVR injects the voltage by Multi level inverter which converts dc voltage in the Energy Storage System (ESS) into ac and the amount of the injection of voltage is controlled by the fuzzy logic controller. Simulation results are presented to illustrate and understand the performances of DVR in supporting load voltage by the waveforms of load voltage without DVR and with DVR. To evaluate the quality of the load voltage during the operation of DVR, Total Harmonic Distortion (THD) is calculated. Keywords Dynamic Voltage Restorer, Energy storage System, Total Harmonic Distortion, Fuzzy Logic Controller, Multi Level Inverter.", "author_names": [ "P Anitha Rani" ], "corpus_id": 212612356, "doc_id": "212612356", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Improvement of Power Quality using DVR in Distribution Systems", "venue": "", "year": 2014 }, { "abstract": "Variable speed electric propulsion motors are operated from a variable frequency drive (VFD) which supplies power to motors at a frequency appropriate to the desired speed. These VFD's are normally very heavy and large in size. A variety of designs are commercially available but they have characteristics unsuitable for ship applications. The objective of this study was to evaluate various options for shipboard applications and to recommend designs that meet navy performance, weight and size constraints. It is possible to dramatically reduce the size and weight of the VFD by optimizing the VFD and the motor as a system, utilizing an optimal distribution voltage, eliminating distribution frequency transformers, and utilizing the weight and size reductions available with liquid cooling. Three systems were studied in detail: cycloconverters, series connected low voltage inverters, and multi level medium voltage inverters using 6 kV class IGBT's or similar switching devices. On the basis of this evaluation, a multi level diode clamped pulse width modulated (PWM) drive topology is recommended for navy ships. A three phase distribution voltage of 6 to 9 kV RMS minimizes the number of series semiconductors and control complexities of the drive.", "author_names": [ "David James Gritter", "Swarn S Kalsi", "N Henderson" ], "corpus_id": 28575961, "doc_id": "28575961", "n_citations": 54, "n_key_citations": 0, "score": 0, "title": "Variable speed electric drive options for electric ships", "venue": "IEEE Electric Ship Technologies Symposium, 2005.", "year": 2005 } ]

[ { "abstract": "Abstract CdZnTe crystal has proved to be an excellent material to detect X ray and gamma ray. Ohmic electrode on CdZnTe wafer is one of the key factors during the fabrication of CdZnTe detector. In this work, the effect of Au/Cd composite electrode on the (111)B (Te rich surface) of CdZnTe wafers with p type conductivity (p CdZnTe) was investigated. The Au/Cd electrode was deposited on the (111)B of CdZnTe wafers by vacuum evaporation method. For comparison, the Au/Zn and Au electrodes were also deposited on CdZnTe (111)B surfaces. The surface and structural properties of the composite electrodes on the (111)B surface of CdZnTe were characterized by the AFM, XPS and SEM. The electrical properties of the electrodes were evaluated by Current Voltage (I V) test. The results show that the surfaces of the Au/Cd and Au/Zn electrodes on (111)B surface were more smooth with less foreign impurities among the interface of the electrode and CdZnTe, as compared to the Au electrode on (111)B surface. The Au/Cd composite electrode can obtain a more ideal ohmic contact than Au/Zn composite electrode on the (111)B surface of CdZnTe wafer. The Au/Cd composite electrode on (111)B surface has the lowest Schottky barrier height, which is attributed to the reduction of the influence of Te enriched surface on the metal semiconductor contact.", "author_names": [ "Liwen Ling", "Jijun Zhang", "Shuhao Zhao", "Delong Zhang", "Jiaxuan Zhang", "Haozhi Shi", "Ke Tang", "Xiaoyan Liang", "Jian Jang Huang", "Jia-hua Min", "Linjun Wang" ], "corpus_id": 132472776, "doc_id": "132472776", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Surface analysis and electrical measurement of the ohmic contact on p CdZnTe (111)B face with Au/Cd composite electrode", "venue": "Materials Science in Semiconductor Processing", "year": 2019 }, { "abstract": "Abstract A series of organic inorganic conducting nano composite cation exchanger have been synthesized via sol gel method and characterized by using FTIR, XRD, TGA DTA, SEM, TEM, AFM and Raman studies. The structural studies confirm the semi crystalline nature of the material with the particle size ranging from 2 to 20 nm. The observed band gap for the different samples was found to be in the range of 3.19 3.65 eV which shows that nano composite materials cover semiconducting range. Activation energy was also calculated using thermo gravimetric analysis. Electrical measurements show that the resistivity of samples is highly dependent on the of inorganic precipitate within the composite. Nano composite material has also been tested against the various bacterial Escherichia coli Bacillus thuringiensis and Pseudomonas aeruginosa and fungal strains Aspergillus nigrus Fusarium oxysporum and Penicillium chrysogenum and relatively higher activities were observed than the known antibiotics.", "author_names": [ "Syed Ashfaq Nabi", "Mohammad Shahadat", "Rani Bushra", "Mohammad Oves", "Faheem Ahmed" ], "corpus_id": 96751183, "doc_id": "96751183", "n_citations": 61, "n_key_citations": 0, "score": 0, "title": "Synthesis and characterization of polyanilineZr(IV)sulphosalicylate composite and its applications (1) electrical conductivity, and (2) antimicrobial activity studies", "venue": "", "year": 2011 }, { "abstract": "HYPOTHESIS Graphene nanoplatelets (GNPs) can be dispersed in natural rubber matrices using surfactants. The stability and properties of these composites can be optimized by the choice of surfactants employed as stabilizers. Surfactants can be designed and synthesized to have enhanced compatibility with GNPs as compared to commercially available common surfactants. Including aromatic groups in the hydrophobic chain termini improves graphene compatibility of surfactants, which is expected to increase with the number of aromatic moieties per surfactant molecule. Hence, it is of interest to study the relationship between molecular structure, dispersion stability and electrical conductivity enhancement for single double and triple chain anionic graphene compatible surfactants. EXPERIMENTS Graphene philic surfactants, bearing two and three chains phenylated at their chain termini, were synthesized and characterized by proton nuclear magnetic resonance (1H NMR) spectroscopy. These were used to formulate and stabilize dispersion of GNPs in natural rubber latex matrices, and the properties of systems comprising the new phenyl surfactants were compared with commercially available surfactants, sodium dodecylsulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS) Raman spectroscopy, field emission scanning electron microscopy (FESEM) atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM) were used to study structural properties of the materials. Electrical conductivity measurements and Zeta potential measurements were used to assess the relationships between surfactant architecture and nanocomposite properties. Small angle neutron scattering (SANS) was used to study self assembly structure of surfactants. FINDINGS Of these different surfactants, the tri chain aromatic surfactant TC3Ph3 (sodium 1,5 dioxo 1,5 bis(3 phenylpropoxy) 3 (3phenylpropoxy)carbonyl) pentane 2 sulfonate) was shown to be highly graphene compatible (nanocomposite electrical conductivity 2.22 x 10 5 S cm 1) demonstrating enhanced electrical conductivity over nine orders of magnitude higher than neat natural rubber latex matrix (1.51 x 10 14 S cm 1) Varying the number of aromatic moieties in the surfactants appears to cause significant differences to the final properties of the nanocomposites.", "author_names": [ "Azmi Mohamed", "Tretya Ardyani", "Suriani Abu Bakar", "Masanobu Sagisaka", "Yasushi Umetsu", "J J Hamon", "Bazura Abdul Rahim", "Siti Rahmah Esa", "H P S Abdul Khalil", "Mohamad Hafiz Mamat", "Stephen M King", "Julian Eastoe" ], "corpus_id": 3532648, "doc_id": "3532648", "n_citations": 21, "n_key_citations": 1, "score": 0, "title": "Rational design of aromatic surfactants for graphene/natural rubber latex nanocomposites with enhanced electrical conductivity.", "venue": "Journal of colloid and interface science", "year": 2018 }, { "abstract": "In this work, layered hybrid composites formed by tin oxide (SnO) nanoparticles synthesized by hydrolysis and poly(3,4 ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) have been analyzed. Prior to the composite study, both SnO and PEDOT:PSS counterparts were characterized by diverse techniques, such as X ray diffraction (XRD) Raman spectroscopy, transmission electron microscopy (TEM) photoluminescence (PL) atomic force microscopy (AFM) optical absorption and Hall effect measurements. Special attention was given to the study of the stability of the polymer under laser illumination, as well as the analysis of the SnO to SnO2 oxidation assisted by laser irradiation, for which different laser sources and neutral filters were employed. Synergetic effects were observed in the hybrid composite, as the addition of SnO nanoparticles improves the stability and electrical conductivity of the polymer, while the polymeric matrix in which the nanoparticles are embedded hinders formation of SnO2. Finally, the Si passivation behavior of the hybrid composites was studied.", "author_names": [ "Antonio Vazquez-Lopez", "Anisa Yaseen", "David Maestre", "Julio Ramirez-Castellanos", "Erik Stensrud Marstein", "Smagul Zh Karazhanov", "A Cremades" ], "corpus_id": 211076859, "doc_id": "211076859", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Synergetic Improvement of Stability and Conductivity of Hybrid Composites formed by PEDOT:PSS and SnO Nanoparticles", "venue": "Molecules", "year": 2020 }, { "abstract": "Abstract An ion imprinting polymer (IIP) electrochemical sensors based on chitosan graphene oxide composites polymer modified glassy carbon electrode (CS/GO IIP) was developed for the highly sensitive and selective detection of Cu (II) by the dip coating method. The Cu (II) ion imprinted polymers were synthesized by chemically cross linking with epichlorohydrin after the CS/GO/Cu (II) composite dropped on the glassy carbon electrode surface. The introduction of GO can improve the electrical conductivity of the electrode and amplify the electrochemical signal. The sensor was characterized by FT IR, EDS, SEM, AFM, Raman spectroscopy and electrochemical measurements. Under the optimized conditions, a linear dependence was observed from 0.5 to 100 mmol/L with a detection limit of 0.15 mmol/L. The detection of Cu (II) was hardly interfered by the traditional metal cations. The CS/GO IIP sensor showed excellent reproducibility via repetitive differential pulse anodic stripping voltammetry and the RSD was 3.3% More importantly, the performance of CS/GO IIP sensor was verified in tap and river water samples and has an acceptable recovery rates.", "author_names": [ "Pengju Wei", "Zhigang Zhu", "Runmin Song", "Zhan-Hong Li", "Cheng Chen" ], "corpus_id": 191165106, "doc_id": "191165106", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "An ion imprinted sensor based on chitosan graphene oxide composite polymer modified glassy carbon electrode for environmental sensing application", "venue": "Electrochimica Acta", "year": 2019 }, { "abstract": "Abstract A new composite material from epoxidized natural rubber (ENR 50) and polyaniline have been successfully prepared. Aniline which was polymerized in the presence of dodecylbenzene sulfonic acid (DBSA) then added to ENR 50 for the preparations of ENR 50/Pani.DBSA composite films. The hydrogen bonding which contribute to the formation of ENR 50/Pani.DBSA composites was observed in FT IR, UV Visible and DSC. It showed hydrogen bonding interactions between the epoxy groups in ENR 50 and the amine groups in Pani.DBSA. The morphologies of the prepared materials were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) SEM and conductivity measurements revealed that the percolation threshold is at 2.5 w% of Pani.DBSA content. Atomic force microscopy (AFM) micrographs showed that ENR 50 with 5 wt% Pani.DBSA addition has the lowest surface roughness. In addition thermogravimetric analysis indicates improved thermal stability at low Pani.DBSA content. DSC measurements revealed that Tg value increases with increasing Pani.DBSA, indicating that the formation of homogenous composite material. Nanoindentation results show that the hardness (H) and Young's modulus (Es) increased with higher addition of Pani.DBSA polymer.", "author_names": [ "Wan Ahmad Kamil Mahmood", "Mohammad Hossein Azarian" ], "corpus_id": 93058442, "doc_id": "93058442", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Thermal, surface, nanomechanical and electrical properties of epoxidized natural rubber (ENR 50) polyaniline composite films", "venue": "", "year": 2015 }, { "abstract": "Jute fibers (JFs) coated with multiwall carbon nanotubes (MWCNTs) have been introduced in a natural rubber (NR) matrix creating a three dimensional (3D) electrically conductive percolated network. The JF CNT endowed electrical conductivity and thermoelectric properties to the final composites. CNT networks fully covered the fiber surfaces as shown by the corresponding scanning electron microscopy (SEM) analysis. NR/JF CNT composites, at 10, 20 and 30 phr (parts per hundred gram of rubber) have been manufactured using a two roll mixing process. The highest value of electrical conductivity (s) was 81 S/m for the 30 phr composite. Thermoelectric measurements revealed slight differences in the Seebeck coefficient (S) while the highest power factor (PF) was 1.80 x 10 2 mW/m K 2 for the 30 phr loading. The micromechanical properties and electrical response of the composite's conductive interface have been studied in peak force tapping quantitative nanomechanical (PFT QNM) and conductive atomic force microscopy (c AFM) mode. The JF CNT create an electrically percolated network at all fiber loadings endowing electrical and thermoelectric properties to the NR matrix, considered thus as promising thermoelectric stretchable materials.", "author_names": [ "Lazaros Tzounis", "Markos Petousis", "Marco Liebscher", "Sotirios A Grammatikos", "Nectarios Vidakis" ], "corpus_id": 219724687, "doc_id": "219724687", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Three Dimensional (3D) Conductive Network of CNT Modified Short Jute Fiber Reinforced Natural Rubber: Hierarchical CNT Enabled Thermoelectric and Electrically Conductive Composite Interfaces", "venue": "Materials", "year": 2020 }, { "abstract": "Conductive particle filled polymer composites are promising materials for applications where both the merits of polymer and conductivity are required. The electrical properties of such composites are controlled by the particle percolation network present in the polymeric matrix. In this study, the electrical properties of crosslinked carbon black epoxy amine (CB EA) composites with various CB concentrations are studied at room temperature as a function of the AC frequency f A transition at critical frequency f c from the DC plateau s DC to a frequency dependent part was observed. Conductivity mechanisms for f f c and f f c were investigated. By considering the fractal nature, conduction for f f c was verified to be intra cluster charge diffusion. For f f c with the assistance of conductive atomic force microscopy (C AFM) the conduction behavior of individual clusters can be observed, revealing both linear and nonlinear I V characteristics. By combining microtoming and C AFM measurements, 3D reconstructed images offer direct evidence that the percolating network of these materials consists of both a low conductivity part, in which the charge transports through tunneling, and a high conductivity part, which shows ohmic electrical properties. Nevertheless, for these CB EA composites, the presence of these non ohmic contacts still leads to Arrhenius type behavior for the macroscopic conductivity.", "author_names": [ "A N Alekseev", "T H Wu", "Leo G J van der Ven", "Rolf A T M van Benthem", "Gijsbertus With" ], "corpus_id": 216032775, "doc_id": "216032775", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Global and local conductivity in percolating crosslinked carbon black/epoxy amine composites", "venue": "Journal of Materials Science", "year": 2020 }, { "abstract": "The role of the interfaces on the optoelectronical properties of porphyrin fullerene composites has been studied by means of ultraviolet visible (UV Vis) and Raman spectroscopy, atomic force microscopy (AFM) and electric conductivity measurements. A simple method of synthesis of donor acceptor complexes has been performed by subsequent deposition of C60 fullerene and tetraphenylporphyrin (H2TPP) thin films, using physical vapor deposition (PVD) on a (100) silicon substrate. UV Vis spectra showed that the interaction of p orbitals leads to a more ordering for the dipole moments arrangement and the p orbitals overlapping between C60 and H2TPP molecules. Besides, Raman spectra presented intensity changes at 960 and 1000 cm 1, both related to the vibration of the pyrrole ring and the rocking of the H on the C atoms within the macrocycle. Therefore, it can be expected that the interface C60 H2TPP should have a main role in the electric response of the multilayer films. The measurements of surface conductivity indicated that interface has specific contribution, and the value of surface conductivity is enhanced by charge delocalization mechanisms occur by p p stacking interactions. It was found that the transversal conductivity of 3 layer films was enhanced by a factor of 4 in comparison to 2 layer film, due to charge transfer mechanisms occur in the junctions that could extend the diffusion length of the charge carriers. Finally, the interface generated between C60 and H2TPP films, without any linking molecule, enhance charge transport mechanism through the films.", "author_names": [ "Edgar Alvarez-Zauco", "Hugo M Sobral", "Erick Martinez-Loran" ], "corpus_id": 201869633, "doc_id": "201869633", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Morphological, Optical and Electrical Characterization of the Interfaces in Fullerene Porphyrin Thin Films.", "venue": "Journal of nanoscience and nanotechnology", "year": 2020 }, { "abstract": "Abstract In this research article, ultrasound assisted exfoliation in a liquid phase production process has been adopted for synthesis of 2D Molybdenum Disulfide (MoS2) The energetic governing dispersion of Nano sheets in a wide range of solvents has been studied. Nano sheets dispersion in an aqueous media has been prepared with the help of high surface tension solvents like N Methyl 1, 2 Pyyrolidone (NMP) and Tetrahydrofuran (THF) The dispersion was composed of layers of MoS2 with some quantities of mono and bi layer materials were observed. Scanning Electron Microscopy (SEM) X Rays Diffractometry (XRD) Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) were used to characterize the samples; SEM clearly evident the microstructure of samples while XRD shows the peaks of filler in the polystyrene composite membrane. AFM confirmed the presence of 2D MoS2 with 0.9 7 nm thickness range of MoS2 flake. In order to get the surfactant stabilized dispersed material, the processing was enhanced using prolonged sonication to yield maximized concentration. Liquid phase exfoliation allows dispersion to be cast into thin film by using vacuum filtration assembly. The obtained film is dispersed in solvent and is used in polymers. Two sets of concentrations (0.01, 0.03, 0.05 and 0.07% by wt. and 0.1, 0.3, 0.7 and 0.9% by wt. were analyzed and it was observed during tensile testing that modulus of elasticity (E) percentage elongation and ultimate tensile strength (UTS) of composite material increases maximum up to 741times, 374 times and 200 times as compared to base polymer (PS) respectively. Furthermore, dielectric constant, dielectric loss and electrical conductivity of PS MoS2 were also evaluated and finding clearly pointed out that filler loading of MoS2 has considerable effects on these properties and maximum value of dielectric constant is 3.6 at 0.9% loading as compared with of pure PS (polystyrene) matrix. On the other hand, variation in dielectric loss from lower to higher frequency is 2.5 x 10 2 on average which is not so significant. Electrical conductivity was also accounted, and measurement results are indicating that conductivity was almost constant at lower frequency in range of 10 10 due to low field strength, but it increases to 10 9 value at higher frequency due to hoping mechanism and network formation of filler.", "author_names": [ "Muhammad Arshad", "Hassan Raza", "Muhammad Bilal Khan", "Arif Hussain" ], "corpus_id": 219926438, "doc_id": "219926438", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Synthesis of 2D Molybdenum Disulfide (MoS2) for enhancement of mechanical and electrical properties of polystyrene (PS) polymer", "venue": "", "year": 2020 } ]

[ { "abstract": "Introduction, D.M. Rowe General Principles and Theoretical Considerations Thermoelectric Phenomena, D.D. Pollock Coversion Efficiency and Figure of Merit, H.J. Goldsmid Thermoelectric Transport Theory, C.M. Bhandari Optimization of Carrier Concentration, C.M. Bhandari and D.M. Rowe Minimizing the Thermal Conductivity, C.M. Bhandari Selective Carrier Scattering in Thermoelectric Materials, Y.I. Ravich Thermomagnetic Phenomena, H.J. Goldsmid Material Preparation Preparation of Thermoelectric Materials from Melts, A. Borshchevsky Powder Metallurgy Techniques, A.N. Scoville PIES Method of Preparing Bismuth Alloys, T. Ohta and T. Kajikawa Preparation of Thermoelectric Materials by Mechanical Alloying, B.A. Cook, J.L. Harringa, and S.H. Han Preparation of Thermoelectric Films, K. Matsubara, T. Koyanagi, K. Nagao, and K. Kishimoto Measurement of Thermoelectric Properties Calculation of Peltier Device Performance, R.J. Buist Measurements of Electrical Properties, I.A. Nishida Measurement of Thermal Properties, R. Taylor Z Meters, H.H. Woodbury, L.M. Levinson, and S. Lewandowski Methodology for Testing Thermoelectric Materials and Devices, R.J. Buist Thermoelectric Materials Bismuth Telluride, Antimony Telluride, and Their Solid Solutions, H. Scherrer and S. Scherrer Valence Band Structure and the Thermoelectric Figure of Merit of (Bi1 xSbx)Te3 Crystals, M. Stordeur Lead Telluride and Its Alloys, V. Fano Properties of the General Tags System, E.A. Skrabek and D.S. Trimmer Thermoelectric Properties of Silicides, C.B. Vining Polycrystalline Iron Disilicide as a Thermoelectric Generator Material, U. Birkholz, E. Gross, and U. Stohrer Thermoelectric Properties of Anisotropic MnSi1.75 V.K. Zaitsev Low Carrier Mobility Materials for Thermoelectric Applications, V.K. Zaitsev, S.A. Ktitorov, and M.I. Federov Semimetals as Materials for Thermoelectric Generators, M.I. Fedorov and V.K. Zaitsev Silicon Germanium, C.B. Vining Rare Earth Compounds, B.J. Beaudry and K.A. Gschneidner, Jr. Thermoelectric Properties of High Temperature Superconductors, M. Cassart and J. P. Issi Boron Carbides, T.L. Aselage and D. Emin Thermoelectric Properties of Metallic Materials, A.T. Burkov and M.V. Vedernikov Neutron Irradiation Damage in SiGe Alloys, J.W. Vandersande New Materials and Performance Limits for Thermoelectric Cooling, G.A. Slack Thermoelectric Generation Miniature Semiconductor Thermoelectric Devices, D.M. Rowe Commercially Available Generators, A.G. McNaughton Modular RTG Technology, R.F. Hartman Peltier Devices as Generators, G. Min and D.M. Rowe Calculations of Generator Performance, M.H. Cobble Generator Applications Terrestrial Applications of Thermoelectric Generators, W.C. Hall Space Applications, G.L. Bennett SP 100 Space Subsystems, J.F. Mondt Safety Aspects of Thermoelectrics in Space, G.L. Bennett Low Temperature Heat Conversion, K. Matsuura and D.M. Rowe Thermoelectric Refrigeration Introduction, H.J. Goldsmid Module Design and Fabrication, R. Marlow and E. Burke Cooling Thermoelements with Superconducting Leg, M.V. Vedernikov and V.L. Kuznetsov Applications of Thermoelectric Cooling Introduction, H.J. Goldsmid Commercial Peltier Modules, K. I. Uemura Thermoelectrically Cooled Radiation Detectors, L.I. Anatychuk Reliability of Peltier Coolers in Fiber Optic Laser Packages, R.M. Redstall and R. Studd Laboratory Equipment, K. I. Uemura Large Scale Cooling: Integrated Thermoelectric Element Technology, J.G. Stockholm Medium Scale Cooling: Thermoelectric Module Technology, J.G. Stockholm Modeling of Thermoelectric Cooling Systems, J.G. Stockholm", "author_names": [ "David Michael Rowe" ], "corpus_id": 107670330, "doc_id": "107670330", "n_citations": 3897, "n_key_citations": 70, "score": 1, "title": "CRC Handbook of Thermoelectrics", "venue": "", "year": 1995 }, { "abstract": "PDF. Twisting phonons in complex crystals with quasi one dimensional substructures Snyder, G. J. Toberer, E. S. Complex thermoelectric materials. Nat. Fedorov, M. I. Zaitsev, V. K. in Thermoelectrics Handbook: Macro to Nano ed. Abstract: The accurate determination of the thermoelectric properties of a Handbook: Macro to Nano, Rowe, D.M. Ed. CRC Taylor and Francis, Boca Raton. thermoelectric efficiencies is an intrinsic phase separation(4) which occurs in multicomponent Half(9) D.M. Rowe, Thermoelectric Handbook:macro to Nano.", "author_names": [ "" ], "corpus_id": 202895343, "doc_id": "202895343", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "mobility in the in plane direction leading to a high thermoelectric power factor In Thermoelectrics Handbook Macro to Nano", "venue": "", "year": 2015 }, { "abstract": "Ten years ago, D.M. Rowe introduced the best selling \"CRC Handbook of Thermoelectrics\" to wide acclaim. Since then, increasing environmental concerns, desire for long life electrical power sources, and continued progress in miniaturization of electronics has led to a substantial increase in research activity involving thermoelectrics. Reflecting the latest trends and developments, the \"Thermoelectrics Handbook: Macro to Nano\" is an extension of the earlier work and covers the entire range of thermoelectrics disciplines. Serving as a convenient reference as well as a thorough introduction to thermoelectrics, this book includes contributions from 99 leading authorities from around the world. Its coverage spans from general principles and theoretical concepts to material preparation and measurements; thermoelectric materials; thermoelements, modules, and devices; and thermoelectric systems and applications. Reflecting the enormous impact of nanotechnology on the field as the thermoelectric properties of nanostructured materials far surpass the performance of conventional materials each section progresses systematically from macro scale to micro/nano scale topics. In addition, the book contains an appendix listing major manufacturers and suppliers of thermoelectric modules. There is no longer any need to spend hours plodding through the journal literature for information. The \"Thermoelectrics Handbook: Macro to Nano\" offers a timely, comprehensive treatment of all areas of thermoelectrics in a single, unified reference.", "author_names": [ "David Michael Rowe" ], "corpus_id": 221203645, "doc_id": "221203645", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Approaches to Thermoelectric Standardization", "venue": "", "year": 2018 }, { "abstract": "Thermoelectric (TE) generators provide electrical energy from direct conversion of heat by means of the Seebeck effect; without moving parts, completely silent, and with negligible maintenance. As any other heat engine this conversion exploits only a fraction of the Carnot efficiency (Rowe (ed. CRC Handbook of Thermoelectrics (CRC Press Inc. 1995) p. 19 1) The TE efficiency is linked to the thermoelectric figure of merit Z, which itself is given by basic material properties: Z S2s/k. These are the electrical conductivity s, the thermal conductivity k and the Seebeck coefficient or thermopower S, which is known as the factor of proportionality between voltage output and applied temperature difference in a given TE sample. A distinct sensitivity to the carrier concentration and structural variations make the control and stabilisation of thermopower very challenging in complex material structures since degradation by diffusion, decomposition or evaporation can be observed in many cases during synthesis, operation and even in the process of characterisation of TE semiconductors; particularly at elevated temperatures. Investigating structural and compositional properties, stability, and performance of TE materials, and consequently aiming to understand their interaction, mainly methods like X ray diffraction (XRD) energy dispersive X ray spectroscopy (EDX) scanning electron microscopy (SEM) or integral temperature dependent measurements of particular transport properties are used. Although TE materials research satisfies highest requirements on accuracy, the above mentioned techniques are not perfectly qualified to investigate promising material classes thoroughly. Against the background of usually complex material structures this article aims to show, that an efficient characterisation of TE materials becomes accessible for several questions by use of a spatially resolved determination of the thermopower.", "author_names": [ "Pawel Ziolkowski", "Gabriele Karpinski", "Titas Dasgupta", "Eckhard Muller" ], "corpus_id": 98746155, "doc_id": "98746155", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Probing thermopower on the microscale", "venue": "", "year": 2013 }, { "abstract": "Mixture models combine multiple components into a single probability density function. They are a natural statistical model for many situations in astronomy, such as surveys containing multiple types of objects, cluster analysis in various data spaces, and complicated distribution functions. This chapter in the CRC Handbook of Mixture Analysis is concerned with astronomical applications of mixture models for cluster analysis, classification, and semi parametric density estimation. We present several classification examples from the literature, including identification of a new class, analysis of contaminants, and overlapping populations. In most cases, mixtures of normal (Gaussian) distributions are used, but it is sometimes necessary to use different distribution functions derived from astrophysical experience. We also address the use of mixture models for the analysis of spatial distributions of objects, like galaxies in redshift surveys or young stars in star forming regions. In the case of galaxy clustering, mixture models may not be the optimal choice for understanding the homogeneous and isotropic structure of voids and filaments. However, we show that mixture models, using astrophysical models for star clusters, may provide a natural solution to the problem of subdividing a young stellar population into subclusters. Finally, we explore how mixture models can be used for mathematically advanced modeling of data with heteroscedastic uncertainties or missing values, providing two example algorithms, the measurement error regression model of Kelly (2007) and the Extreme Deconvolution model of Bovy et al. (2011) The challenges presented by astronomical science, aided by the public availability of catalogs from major surveys and missions, are a rich area for collaboration between statisticians and astronomers.", "author_names": [ "Michael A Kuhn", "Eric D Feigelson Millennium Institute of Astrophysics", "Universidad de Valpara'iso", "Pennsylvania State University" ], "corpus_id": 88523130, "doc_id": "88523130", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Mixture Models in Astronomy", "venue": "", "year": 2017 }, { "abstract": "The increased worldwide demand for electricity has driven the scientific community to find alternative, renewable and sustainable energy sources resulting in a reduced emission of carbon dioxide. However it is ironic and striking that a significant proportion of the energy generated is lost as waste heat and only 40% of it is utilized to serve the purpose of human society. Regarding this, at present thermoelectric materials have garnered lot of attentions due to its capability of power generation by scavenging the waste heat. Moreover, thermoelectric (TE) devices found a wide range of application in various fields such as automotive, military equipment, aerospace, and medical industries. However, the key factor is to attain high thermoelectric device figure of merit, ZT S2sT/k, which determines the quality and performance of a TE material. In this relation, Seebeck coefficient (S) and electrical conductivity (s) should be high, and thermal conductivity (k) should be low, so as to attain the high ZT value. But, it is rather difficult to control the parameters S, s, and k independently, as they are interlinked with each other. However, among these three parameters, thermal conductivity is the crucial factor in determining ZT. It is represented as k ke kl. In this expression, ke defines the heat transport via electrons and kl defines the heat transport by lattice vibrations called phonons. The way ke related to s, it is very clear that drops in ke value will further reduce the s. Their dependency proves that to obtain the high ZT value, it is necessary to minimize the other part of k, i.e. kl. In this respect, primarily two popular tactics have been emerged for increasing the ZT: PGEC (phonon glass electron crystal) concept by Slack (Slack, New materials and performance limits for thermoelectric cooling. In: Rowe DM (ed) CRC Handbook of Thermoelectrics. Taylor and Francis, London, p 407, 1995) and the idea of nanostructuring by Dresselhaus and Hicks (Dresselhaus et al. 2007; Hicks et al. Phys Rev B 53:10493 10496, 1996)", "author_names": [ "Sunanda Mitra", "Tanmoy Maiti" ], "corpus_id": 139663470, "doc_id": "139663470", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Thermoelectric Materials Synthesized by Spark Plasma Sintering (SPS) for Clean Energy Generation", "venue": "", "year": 2019 }, { "abstract": "Ben Jiang Yan deha, Bi Zhe ranoYan Jiu gurupugaXian Zai Qu ri Zu ndeiru Si nanowaiyawoYong itamaikuroRe Dian Fa Dian debaisunoKai Fa woShao Jie shinagara, IVShu Hun Jing Xi henoZhan Kai noJian Tong shiwoShi sukotonishitai. Re Dian Cai Liao noXing Neng haWu Ci Yuan Xing Neng Zhi Shu ZT=as T/knoDa kisadePing Jia sareru. ahazebetsukuXi Shu shaDian Qi Chuan Dao Lu khaRe Chuan Dao Lu ThaGao Wen oyobiDi Wen Re Yuan noPing Jun Wen Du dearu. Re Dian Bian Huan Xiao Lu ha ZT Zhi noZeng Da totomoniXiang Shang shi, ZT noJi Xian dekarunoXiao Lu tonaru. Shen Yu Zhou Tan Cha Ji noYuan Zi Li Dian Chi deha Si80Ge20gaYong irareteori, sonoYi Wei deIVShu Hun Jing haShi Yong De Re Dian Cai Liao noDai Biao Ge toi eru. Simo Ge mozebetsukuXi Shu Dian Qi Chuan Dao Lu tomoniDa kinaCai Liao daga, Re Chuan Dao Lu gaFei Chang niDa ki itame ZT haFei Chang niXiao sai. tokorogaLiang Zhe noHun Jing nisurutohuononnoPing Jun Zi You Xing Cheng gaDuan kuna tsuteGe Zi Re Chuan Dao Lu gaJi Jian shi, 1000degCFu Jin de ZT ~1 noShi Yong reberuniDa suru. Ben Gao deShao Jie surumaikuroRe Dian Fa Dian debaisu ha, enazihabesuteingu(EH)Ying Yong wo Mu Zhi shiteirutame, Ti Wen yaShi Wen aruihaZi Dong Che noPai Re Cheng Du noWen Du Ling Yu deGao iXing Neng woFa Hui su rukotogaQiu merareru. EH Ying Yong woMu Zhi suRe Dian Cai Liao demo ZT noXiang Shang gaMu Biao niJie gerarerukotogaDuo iga, somosomoDian Yuan niYao Qiu sareruXing Neng ha, Shao na ikosutodeDuo kunoDian Li woSheng miChu suNeng Li dearu. Dan Wei Fa Dian Liang woSheng miChu sutameniYao suruenerugi Yuan nokosuto(Ran Liao kosuto)wo cf(/Wh) Re Dian moziyuru1Ge noZhi Zao kosutowo cm()tosu ruto, Dan Wei Fa Dian Liang Dang tarinokosuto c(/Wh)ha c cm/pt cf/e deBiao sareru. p haRe Dian Fa Dian moziyuru1Ge no Ping Jun Fa Dian Li (W) thamoziyurunoPing Jun Shou Ming (h) ehaRe Dian Bian Huan Xiao Lu woBiao su. ZT noXiang Shang deegaZeng Da suruga, Ti Wen yaHuan Jing Fa Dian noyouniRan Liao kosuto cf gaWu Shi dekiruChang He ZT haShi hasorehodoZhong Yao denaku, mushiropawahuakuta(PF=as)ga Da kiiCai Liao deDi kosutoQie tsuGao Shou Ming noFa Dian mozi yuruwoShi Xian surukotogaZhong Yao tonaru. Si mai kuroRe Dian debaisuniQi Dai gaJi serareteiruLi You ha CMOS purosesudeZhi Zao kosutowoYi erareru karadeari, sonoChang He Zhui Qiu subekiXing Neng ha ZT yo rimushiro PF noFang dehanaikatoBi Zhe rahaKao eru. Bi Zhe ranoYi Bu ha, Wei Xi Hua Gao Ji Ji Hua suruhodo Dan Wei Mian Ji Dang tarinoFa Dian pawagaXiang Shang suru\"suke raburupurenaXing Si Re Dian Fa Dian debaisu\" woKao An shi(Fig.1 Can Zhao Shi Yan De nimoWei Xi Hua Xiao Guo woShi Zheng shiteiru. SiGe nanowaiyawoYong i taRe Dian Fa Dian Shi Yan nimoZhao Shou shiteiruga, SiGe ha Siyorimo PFgaXiao saku, mushiroBian Huan Xiao Lu woZhong Shi suruYong Tu niXiang iteiru. Jin Nian Zhu Mu sareteiru GeSn Hun Jing ha, Sn Nong Du 10%Yi Shang debandoGou Zao ga Bian Hua shiteYi Dong Du gaZeng sutoKao erareteori, ZT mo PF moDa kinaRe Dian Cai Liao tonaruKe Neng Xing gaaru. tadashiGao Xiao Lu noRe Dian Fa Dian moziyuruniha n Xing to pXing noLiang Fang gaBi Yao deari, sorezoreniZui Shi na Cai Liao woHun Zai dekirupurosesugaBi Yao ninarukamo Zhi renai. nanowaiyaHua dehuononnoBiao Mian San Luan Pin Du gaZeng Da shiRe Chuan Dao Lu gaDa Fu niDi Xia suruga, Biao Mian San Luan toHun Jing Hua noXiang Cheng De Xiao Guo gaJian Ip merukado ukamoJin Hou Ming rakanishiteikuBi Yao gaaru. nao, Ben Jiang Yan deShao Jie suruYan Jiu ha JST CREST JPMJCR15Q7 )narabini JST sakigake (JPMJPR15R2)noZhu Cheng woShou keteXing wareta. Can Kao Wen Xian [1] Gao Min, \"Chapter 11: Thermoelectric Module Design Theories,\" Thermoelectrics Handbook, ed. by D. M. Rowe, CRC Press. [2] T. Watanabe et al. EDTM2017, pp.86 87. [3] S. Hashimoto, M. Kurosawa, T. Watanabe et al, EDTM2018. Di 65Hui Ying Yong Wu Li Xue Hui Chun Ji Xue Shu Jiang Yan Hui Jiang Yan Yu Gao Ji (2018 Zao Dao Tian Da Xue Xi Zao Dao Tian kiyanpasu) 18p C304 11", "author_names": [ "Takanobu Watanabe", "Shuichiro Hashimoto", "Motohiro Tomita", "Masashi Kurosawa", "Hiroya Ikeda" ], "corpus_id": 115987465, "doc_id": "115987465", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Applicability of Group IV Alloys to Micro Thermoelectric Generators", "venue": "", "year": 2018 }, { "abstract": "Complexity of the crystal structures is one of the key issues in the further understanding of the structure dependent physical behaviors in particular thermoelectric properties of materials. It is well accepted approach for realization of good thermoelectric materials which suggests the use of elements with atomic masses, large carrier mobility and compounds with large unit cells (complex crystal structures) for reducing the thermal conductivity and controlling the electronic transport [1] Being a philosophical category for the description of the state of the mind, complexity is not easy to be straight forward quantified. Structural complexity of compounds may be described in several ways, e.g. on base of the crystallographic features of materials (number of atoms in the unit cell or symmetry) or considering chemical and crystallographic order/disorder, or taking into account thermodynamic factors (phase diagrams, formation reactions) etc. According to crystallographic description, a special family of materials the so called complex metallic alloys or phases (CMA) was defined in order to shed more light on the influence of their unusual crystal structures on the chemical and physical properties [2] Experimental studies on single crystals revealed that neither electronic nor thermal transport behaviors follow strictly the crystallographic understanding of structural complexity. As a promising results in this direction, recently was shown that the reduced lattice thermal conductivity of type I clathrates without vacancies and with respect to such with ordered vacancies suggests that disordered vacancies disturb the heat transport more efficient as the electronic transport. Further insights into the phonon transport are achieved considering the complexity of appearance and spatial separation of regions with different chemical bonding in the context of the structural complexity. Inhomogeneity and anisotropy of chemical bonding support the reduction of the thermal conductivity in dependence of crystallographic direction [3] [1] Slack, G. A. (1995) In: Thermoelectric Handbook. Ed. D. M. Rowe .CRC, Boca Raton, FL 407ff. [2] Steurer, W. Dshemuchadse, J. (2016) Intermetallics. Oxford University Press. [3] Ormeci A. et al. (2015) J. Thermoelectr. No 6, 16 32.", "author_names": [ "Yu N Grin" ], "corpus_id": 103584826, "doc_id": "103584826", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Complexity of crystal structures and properties of thermoelectric materials", "venue": "", "year": 2017 }, { "abstract": "We report on the experimental observation of coherent phonon boundary scattering in micro scale phononic crystals (PnCs) at room temperature. We show that the neglecting coherent boundary scattering leads to gross overestimation of the measured thermal conductivities of the PnC samples. We introduce a hybrid model that accounts for partial coherent and partial incoherent phonon boundary scattering. Excellent agreement with the experiment is achieved. Almost all physical processes produce heat as a byproduct making thermoelectric (TE) systems very attractive for energy scavenging applications. Energy conversion in TE devices is based on the so called Peltier effect 1 Here the temperature gradient resulting from expelled heat is used to force electronic transport resulting in an electric current. As such, heat transported via phonons represents a leakage mechanism and serves to reduce the efficiency of TE systems. Indeed the inability to suppress or eliminate the relative phonon contribution to thermal transport as compared to the electronic one has hindered the development of efficient TE devices. Recently, it has been proposed that coherent boundary scattering in micro scale phononic crystals (PnCs) may hold the key to solving this problem by scattering phonons with minimal influence on electrons 2 4 PnCs are artificial structures with a periodic variation in mechanical impedance brought about by the introduction of holes or plugs of one material into a homogenous matrix of another 5 8 This periodic variation results in rich phonon dispersion with unusual behaviors 9 In this communication, we focus on micro scale PnCs formed by the introduction of air holes in a Si matrix with minimum feature sizes 100nm. As a phonon population traverses such a lattice, it can undergo two types of scattering processes: simple incoherent scattering as a result of encountering a boundary; and coherent Bragg like 7 scattering due to the periodic topology of the artificial lattice of air holes. In the first type, it is assumed that the phonons will retain no phase information after each scattering event. This implies that the phonon dispersion remains unaltered due to the introduction of the air holes. In the second type, on the other hand, it is assumed that the phase is preserved throughout several scattering events thus enabling coherent interference to occur. Consequently, this would imply a modified phonon dispersion that is sensitive to the topology of the PnC air hole lattice. Practically, this can have profound implications because: while incoherent boundary scattering depends only on the shape, size, and separation of the holes; coherent boundary scattering additionally depends on the symmetry and topology by which these holes are distributed. Thus, the existence of coherent scattering would allow one to further reduce the thermal conductivity of the underlying material without the need for additional boundaries (e.g. more air holes) by simply altering the PnC topology. The claim of coherent phonon scattering in micro scale Si/Air PnCs at room temperature has generated widespread controversy in the literature given the relatively small wavelength characteristic of the phonon population dominating the thermal transport 3,10 14 Experimentally however, the thermal conductivity (k) of PnC samples have consistently been measured to be significantly lower than that of an unpatterned film 2,4,11,13,14 In fact far lower than what would be expected due to the combination of material removal and simple incoherent boundary scattering 2,4,13 thereby suggesting that another k reduction mechanism, possibly coherent scattering, must be taking place. The The 2nd Intenational Conference on Phononics and Thermal Energy Science (PTES2014) Shanghai, China, May 26 May 31, 2014 controversy was heightened by the discovery that ~50% of k in Si is carried by phonons with mean free paths (MFPs) from 100nm up to 1mm15, which was recently verified experimentally 16 Since it is logical to assume that a phonon remains coherent over its MFP, we suggest here that the MFP, rather than wavelength, should be used when judging whether or not coherent scattering events can take place. In which case, a large enough fraction of the phonon population could travel sufficient distances to experience the PnC lattice periodicity and thus undergo coherent scattering. We report on the experimental observation of coherent phonon boundary scattering in micro scale phononic crystals (PnCs) at room temperature. We investigate the existence of coherent phonon boundary scattering resulting from the periodic topology of the PnCs and its influence on the thermal in silicon. To delaminate incoherent from coherent boundary scattering, PnCs with a fixed minimum feature size, differing only in the unit cell topologies, were fabricated. A suspended island platform was used to measure the thermal conductivity. We show that the neglecting coherent boundary scattering leads to gross overestimation of the measured thermal conductivities of the PnC samples. We introduce a hybrid model that accounts for partial coherent and partial incoherent phonon boundary scattering. Excellent agreement with the experiment is achieved emphasizing the influence of coherent zone folding in PnCs. Our results yield conclusive evidence that significant room temperature coherent phonon boundary scattering does indeed take place. References 1 Slack, G. A. CRC Handbook of Thermoelectrics. (CRC Press, 1995) Hopkins, P. E. et al. Reduction in the Thermal Conductivity of Single Crystalline Silicon by Phononic Crystal Patterning. Nano Lett 11, 107 112, doi:Doi 10.1021/Nl102918q (2011) 3 Reinke, C. M. et al. Thermal conductivity prediction of nanoscale phononic crystal slabs using a hybrid lattice dynamics continuum mechanics technique. AIP Advances 1, 041403 041414 (2011) 4 Yu, J. K. Mitrovic, S. Tham, D. Varghese, J. Heath, J. R. Reduction of thermal conductivity in phononic nanomesh structures. Nature Nanotechnology, 5, 718 721, (2010) 5 Reinke, C. M. Su, M. F. Olsson, R. H. El Kady, I. Realization of optimal bandgaps in solid solid, solid air, and hybrid solid air solid phononic crystal slabs. Appl Phys Lett 98, doi:Artn 061912 Doi 10.1063/1.3543848 (2011) 6 Su, M. F. Olsson, R. H. Leseman, Z. C. El Kady, I. Realization of a phononic crystal operating at gigahertz frequencies. Appl Phys Lett 96, 053111 (053113 pp. doi:10.1063/1.3280376 (2010) 7 Olsson, R. H. III et al. in IEEE International Ultrasonics Symposium. 1150 1153. 8 El Kady, I. Olsson, R. H. III Fleming, J. G. Phononic band gap crystals for radio frequency communications. Appl Phys Lett 92, 233504 233501 233503, doi:10.1063/1.2938863 (2008) 9 Kushwaha, M. S. Halevi, P. Dobrzynski, L. Djafari Rouhani, B. Acoustic band structure of periodic elastic composites. Physical Review Letters 71, 2022 2025 (1993) 10 Hao, Q. Chen, G. Jeng, M. S. Frequency dependent Monte Carlo simulations of phonon transport in two dimensional porous silicon with aligned pores. Journal of Applied Physics 106, 114321 114310 (2009) 11 Tang, J. et al. Holey Silicon as an Efficient Thermoelectric Material. Nano Lett 10, 4279 4283, doi:10.1021/nl102931z (2010) 12 Jain, A. Yu, Y. J. McGaughey, A. J. H. Phonon transport in periodic silicon nanoporous films with feature sizes greater than 100 nm. Physical Review B 87, 195301 (2013) 13 Bongsang, K. et al. in Micro Electro Mechanical Systems (MEMS) 2012 IEEE 25th International Conference on 176 179 (2012) 14 El Kady, I. et al. Phonon Manipulation with Phononic Crystals. (Sandia National Laboratories, 2012) 15 Esfarjani, K. Chen, G. Stokes, H. T. Heat transport in silicon from first principles calculations. Physical Review B 84, 085204 (2011)", "author_names": [ "Ihab El-Kady", "Charles M Reinke", "Seyedhamidreza Alaie", "Drew F Goettler", "Mehmet F Su", "Zayd C Leseman" ], "corpus_id": 123791915, "doc_id": "123791915", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Thermal Transport in Micro Scale Phononic Crystals: Observation of Coherent Phonon Scattering at Room Temperature.", "venue": "", "year": 2014 }, { "abstract": "Zintl phases are promising thermoelectric materials especially because of their so called 'electron crystal, phonon glass' behaviour[1] This work focuses on high temperature thermoelectric properties of the ternary 1 2 2 Zintl phases Ca1 xAxAl2 yMySi2 (A Sr, Ba; M Zn, Mn)[2] Compounds with the CaAl2Si2 structure type are known to be interesting thermoelectric materials, an example is CaZn2Sb2 [3] Low temperature measurements (10 300 K) of the thermoelectric properties for CaAl2Si2 were recently described[4] We were interested in the thermoelectric potential of compounds with the general composition Ca1 xAxAl2 yMySi2. Synthesis of the materials was done via arc melting technique. The samples were characterized, densified (hot pressing, SPS) and investigated with respect to their thermoelectric properties (compare [5] Characterization methods include X ray powder diffraction, scanning electron microscopy and energy dispersive X ray spectroscopy. Furthermore high temperature thermal analysis, Seebeck, electrical and thermal conductivity measurements were done. The results will be discussed as well as the influence of the compositional variation of x and y. While substitution with an alkaline earth metal should reduce the thermal conductivity, doping aluminium with zinc or manganese should have an effect on the electrical properties of the material since the conductivity is present mainly in the Al2Si2 layers. [1] G. A. Slack, in CRC Handbook of Thermoelectrics, ed. D. M. Rowe, CRC Press, New York, 1995, 407 440. [2] C. Kranenberg, D. Johrendt, A. Mewis, Z. Anorg. Allg. Chem. 1999, 625, 1787. [3] E. S. Toberer, A. F. May, B. C. Melot, E. Flage Larsen, G. J. Snyder, Dalton Trans. 2010, 39, 1046. [4] Y. K. Kuo, K. M. Sivakumar, J. I. Tasi, C. S. Lue, J. W. Huang, S. Y. Wang, D. Varshney, N. Kaurav, R. K. Singh, J. Phys. Condens. Matter 2007, 19, 176206. [5] M. Moller, G. Cordier, K. Hofmann, B. Albert, Z. Anorg. Allg. Chem. 2012, 638, 1637.", "author_names": [ "Matthias Moller", "Johannes de Boor", "Eckhard Muller", "Barbara Albert" ], "corpus_id": 92227274, "doc_id": "92227274", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High temperature thermoelectric properties of the compound CaAl2Si2 and effects of substitution and doping", "venue": "", "year": 2013 } ]

[ { "abstract": "When an electron hole pair is optically excited in a semiconductor quantum dot, the host crystal lattice adapts to the presence of the generated charge distribution. Therefore, the coupled exciton phonon system has to establish a new equilibrium, which is reached in the form of a quasiparticle called a polaron. Especially, when the exciton is abruptly generated on a timescale faster than the typical lattice dynamics, the lattice cannot follow adiabatically. Consequently, rich dynamics on the picosecond timescale of the coupled system is expected. In this study, we combine simulations and measurements of the ultrafast, coherent, nonlinear optical response, obtained by four wave mixing (FWM) spectroscopy, to resolve the formation of this polaron. By detecting and investigating the phonon sidebands in the FWM spectra for varying pulse delays and different temperatures, we have access to the influence of phonon emission and absorption processes, which finally result in the emission of an acoustic wave packet.", "author_names": [ "Daniel Wigger", "Vage Karakhanyan", "Christian Schneider", "Martin Kamp", "Sven Hofling", "Pawel Machnikowski", "Tilmann Kuhn", "Jacek Kasprzak" ], "corpus_id": 210116540, "doc_id": "210116540", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Acoustic phonon sideband dynamics during polaron formation in a single quantum dot.", "venue": "Optics letters", "year": 2020 }, { "abstract": "A long lived hot carrier in organic inorganic hybrid perovskite materials is possibly assisted by the large polaron and hot phonon bottleneck. The phonon plays a significant role in the properties of hybrid perovskites. Coherent phonon refers to the in phase vibration of the crystal lattice. Here, temperature dependent, fluence dependent, and polarization dependent transient absorption spectroscopy is utilized to study the coherent phonon in methylammonium lead iodide. A coherent optical phonon is observed due to the existence of Pb I Pb angular distortion at 24 33 cm 1 in both tetragonal and orthorhombic phases. Oscillation from the excited state absorption is also observed, suggesting coupling between the coherent phonon and photoexcited state. Oscillation of the coherent phonon attenuates with increasing environmental temperature. The dependence of the coherent phonon on polarization of the pulse and quantitative analysis indicates that the generation mechanism is impulsive stimulated Raman scattering", "author_names": [ "Chengbin Fei", "Julio S Sarmiento", "He Wang" ], "corpus_id": 105121906, "doc_id": "105121906", "n_citations": 8, "n_key_citations": 0, "score": 1, "title": "Generation of Coherent Optical Phonons in Methylammonium Lead Iodide Thin Films", "venue": "", "year": 2018 }, { "abstract": "Femtosecond optical pump probe spectroscopy is used to reveal the influence of charge and magnetic order on polaron dynamics and coherent acoustic phonon oscillations in single crystals of charge ordered, ferrimagnetic LuFe2O4. We experimentally observed the influence of magnetic order on polaron dynamics. We also observed a correlation between charge order and the amplitude of the acoustic phonon oscillations, due to photoinduced changes in the lattice constant that originate from the photoexcited electrons. This provides insight into the general behavior of coherent acoustic phonon oscillations in charge ordered materials.", "author_names": [ "Jihye Lee", "S A Trugman", "Chenglin Zhang", "Diyar Talbayev", "Xiaoshan Xu", "Sang-Wook Cheong", "Dmitry Anatolievitch Yarotski", "Antoinette J Taylor", "Rohit Prativadi Prasankumar" ], "corpus_id": 11961942, "doc_id": "11961942", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "The influence of charge and magnetic order on polaron and acoustic phonon dynamics in LuFe2O4", "venue": "", "year": 2015 }, { "abstract": "Hematite (a Fe2O3) is the most studied artificial oxygen evolving photo anode and yet its efficiency limitations and their origin remain unknown. A sub picosecond reorganisation of the hematite structure has been proposed as the mechanism which dictates carrier lifetimes, energetics and the ultimate conversion yields. However, the importance of this reorganisation for actual device performance is unclear. Here we report an in situ observation of charge carrier self localisation in a hematite device, and demonstrate that this process affects recombination losses in photoelectrochemical cells. We apply an ultrafast, device based optical control method to resolve the subpicosecond formation of small polarons and estimate their reorganisation energy to be ~0.5 eV. Coherent oscillations in the photocurrent signals indicate that polaron formation may be coupled to specific phonon modes <100 cm 1) Our results bring together spectroscopic and device characterisation approaches to reveal new photophysics of broadly studied hematite devices. The efficiency of Hematite (a Fe2O3) photo anodes is thought to be limited by ultrafast lattice distortions or polarons. Here, we use an optical control method with photocurrent detection to track small polarons in real time and demonstrate that they impact photoelectrochemical cell activity", "author_names": [ "Ernest Pastor", "Ji-Sang Park", "Ludmilla Steier", "Sunghyun Kim", "Michael Gratzel", "James R Durrant", "Aron Walsh", "Artem A Bakulin" ], "corpus_id": 201716493, "doc_id": "201716493", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "In situ observation of picosecond polaron self localisation in a Fe2O3 photoelectrochemical cells", "venue": "Nature Communications", "year": 2019 }, { "abstract": "The long carrier lifetime and defect tolerance in metal halide perovskites (MHPs) are major contributors to the superb performance of MHP optoelectronic devices. Large polarons were reported to be responsible for the long carrier lifetime. Yet microscopic mechanisms of the large polaron formation including the so called phonon melting, are still under debate. Here, time of flight (TOF) inelastic neutron scattering (INS) experiments and first principles density functional theory (DFT) calculations were employed to investigate the lattice vibrations (or phonon dynamics) in methylammonium lead iodide \\rm{MAPbI_3} a prototypical example of MHPs. Our findings are that optical phonons lose temporal coherence gradually with increasing temperature which vanishes at the orthorhombic to tetragonal structural phase transition. Surprisingly, however, we found that the spatial coherence is still retained throughout the decoherence process. We argue that the temporally decoherent and spatially coherent vibrations contribute to the formation of large polarons in this metal halide perovskite.", "author_names": [ "Depei Zhang", "Xiao Jun Hu", "Tianran Chen", "Douglas L Abernathy", "Ryoichi Kajimoto", "Mitsutaka Nakamura", "Maiko Kofu", "Benjamin J Foley", "Mina Yoon", "Joshua J Choi", "Seung-Hun Lee" ], "corpus_id": 221139705, "doc_id": "221139705", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Temporally decoherent and spatially coherent vibrations in metal halide perovskite.", "venue": "", "year": 2020 }, { "abstract": "Abstract We investigated the optical response of La0.67Sr0.33MnO3 (LSMO) films which show the metal insulator transition (MIT) with the film thickness dependence. By using spectroscopic ellipsometric technique we found that the optical spectra below the charge transfer gap exhibited the coherent incoherent crossover behavior through MIT. The formation of the incoherent mode near 1.5 eV was reminiscent of the polaron absorption which had been widely observed in various manganites. We suggest that the electron phonon coupling could be enhanced due to low dimensionality in the ultrathin LSMO film in consideration of orbital polarization.", "author_names": [ "Il Wan Seo", "Yunsang Lee", "Ji-Won Seo", "Seung Hyub Baek" ], "corpus_id": 197138915, "doc_id": "197138915", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Optical investigation of the metal insulator transition in the manganite films with the thickness dependence", "venue": "Current Applied Physics", "year": 2019 }, { "abstract": "We investigate the effects of a nearly uniform Bose Einstein condensate (BEC) on the properties of immersed trapped impurity atoms. Using a weak coupling expansion in the BEC impurity interaction strength, we derive a model describing polarons, i.e. impurities dressed by a coherent state of Bogoliubov phonons, and apply it to ultracold bosonic atoms in an optical lattice. We show that, with increasing BEC temperature, the transport properties of the impurities change from coherent to diffusive. Furthermore, stable polaron clusters are formed via a phonon mediated off site attraction.", "author_names": [ "Martin Bruderer", "Alexander Klein", "Stephen R Clark", "Dieter Jaksch" ], "corpus_id": 21659581, "doc_id": "21659581", "n_citations": 100, "n_key_citations": 6, "score": 0, "title": "Polaron Physics in Optical Lattices", "venue": "", "year": 2007 }, { "abstract": "Mixed valence O doped UO2+x and photoexcited UO2 containing transitory U3+ and U5+ host a coherent polaronic quantum phase (CPQP) that exhibits the characteristics of a Frohlich type, nonequilibrium, phonon coupled Bose Einstein condensate whose stability and coherence are amplified by collective, anharmonic motions of atoms and charges. Complementary to the available, detailed, real space information from scattering and EXAFS, an outstanding question is the electronic structure. Mapping the Mott gap in UO2, U4O9, and U3O7 with O XAS and NIXS and UM5 RIXS shows that O doping raises the peak of the U5f states of the valence band by ~0.4 eV relative to a calculated value of 0.25 eV. However, it lowers the edge of the conduction band by 1.5 eV vs the calculated 0.6 eV, a difference much larger than the experimental error. This 1.9 eV reduction in the gap width constitutes most of the 2 2.2 eV gap measured by optical absorption. In addition, the XAS spectra show a tail that will intersect the occupied U5f states and give a continuous density of states that increases rapidly above its constricted intersection. Femtosecond resolved photoemission measurements of UO2, coincident with the excitation pulse with 4.7 eV excitation, show the unoccupied U5f states of UO2 and no hot electrons. 3.1 eV excitation, however, complements the O doping results by giving a continuous population of electrons for several eV above the Fermi level. The CPQP in photoexcited UO2 therefore fulfills the criteria for a nonequilibrium condensate. The electron distributions resulting from both excitations persist for 5 10 ps, indicating that they are the final state that therefore forms without passing through the initial continuous distribution of nonthermal electrons observed for other materials. Three exceptional findings are: (1) the direct formation of both of these long lived >3 10 ps) excited states without the short lived nonthermal intermediate; (2) the superthermal metallic state is as or more stable than typical photoinduced metallic phases; and (3) the absence of hot electrons accompanying the insulating UO2 excited state. This heterogeneous, nonequilibrium, Frohlich BEC stabilized by a Fano Feshbach resonance therefore continues to exhibit unique properties.", "author_names": [ "Steven D Conradson", "David A Andersson", "Kevin S Boland", "J A Bradley", "Darrin D Byler", "Tomasz Durakiewicz", "Steve M Gilbertson", "Stosh Anthony Kozimor", "Kristina O Kvashnina", "Dennis Nordlund", "George Rodriguez", "Gerald T Seidler", "Paul S Bagus", "Sergei M Butorin", "Dylan R Conradson", "F J Espinosa-Faller", "Nancy J Hess", "Joshua J Kas", "Juan S Lezama-Pacheco", "Philippe M Martin", "Mary B Martucci", "John J Rehr", "James Anthony Valdez", "Alan R Bishop", "Gianguido Baldinozzi", "David L Clark", "Akhil Tayal" ], "corpus_id": 39818277, "doc_id": "39818277", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Closure of the Mott gap and formation of a superthermal metal in the Frohlich type nonequilibrium polaron Bose Einstein condensate in U O 2 x", "venue": "", "year": 2017 }, { "abstract": "Electron transport in periodic quantum dot arrays in the presence of interactions with phonons was investigated using the formalism of nonequilibrium Green's functions. The self consistent Born approximation was used to model the self energies. Its validity was checked by comparison with the results obtained by direct diagonalization of the Hamiltonian of interacting electrons and longitudinal optical phonons. The nature of charge transport at electron phonon resonances was investigated in detail and contributions from scattering and coherent tunneling to the current were identified. It was found that at larger values of the structure period, the main peak in the current field characteristics exhibits a doublet structure which was shown to be a transport signature of polaron effects. At smaller values of the period, electron phonon resonances cause multiple peaks in the characteristics. A phenomenological model for treatment of nonuniformities of a realistic quantum dot ensemble was also introduced to estimate the influence of nonuniformities on current field characteristics.", "author_names": [ "Nenad Vukmirovi'c", "Zoran Ikoni'c", "Dragan Indjin", "Paul Harrison" ], "corpus_id": 119685642, "doc_id": "119685642", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Quantum transport in semiconductor quantum dot superlattices: Electron phonon resonances and polaron effects", "venue": "", "year": 2007 }, { "abstract": "We present a theory of the optical line shape of coherent intersubband transitions in a semiconductor quantum well, considering non Markovian LO phonon scattering as major broadening mechanism. We show that a quantum kinetic approach leads to additional polaron resonances and a resonance enhancement for gap energies close to the phonon energy.", "author_names": [ "Stefan Butscher", "Jens Forstner", "I Waldmuller", "Andreas Knorr" ], "corpus_id": 121509069, "doc_id": "121509069", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Polaron signatures in the line shape of semiconductor ;intersubband transitions: quantum kinetics of the electron phonon interaction", "venue": "", "year": 2004 } ]

[ { "abstract": "We developed a chemical route to produce graphene nanoribbons (GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice defined graphene junctions for potential molecular electronics. The GNRs were solution phase derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges with possibly well defined zigzag or armchair edge structures. Electrical transport experiments showed that, unlike single walled carbon nanotubes, all of the sub 10 nanometer GNRs produced were semiconductors and afforded graphene field effect transistors with on off ratios of about 107 at room temperature.", "author_names": [ "Xiaolin Li", "Xinran Wang", "Li Zhang", "Sangwon Lee", "Hongjie Dai" ], "corpus_id": 37977686, "doc_id": "37977686", "n_citations": 3962, "n_key_citations": 40, "score": 1, "title": "Chemically Derived, Ultrasmooth Graphene Nanoribbon Semiconductors", "venue": "Science", "year": 2008 }, { "abstract": "", "author_names": [ "Xiaolin Li", "Xinran Wang", "Li Zhang", "Sangwon Lee", "H Dai" ], "corpus_id": 26513040, "doc_id": "26513040", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Supporting Online Material for Chemically Derived Ultrasmooth Graphene Nanoribbon Semiconductors", "venue": "", "year": 2008 }, { "abstract": "Abstract We investigate the effect of out layer strain on the electronic and transport properties of chemically functionalized hybrid b AGNR systems, which are formed by partial hydrogenation and fluorination (or hydrofluorination) in the middle parts of bilayer armchair graphene nanoribbon, using density functional theory and nonequilibrium Green's function techniques. The calculated formation energies show that all hybrid systems have negative formation energies, thus, they are stable with respect to molecular desorption. Especially, the fluorinated hybrid system is more stable than others, due to higher electronegativity of F than H atoms. From calculated band structures, we reveal that the hybrid systems are the semiconductors with band gaps of about 0.09 eV 1.55 eV as function of nanoroad width and out layer strain. Especially, the band gaps of the hybrid systems with nanoroad width show the order of 3 nanoroad 5 nanoroad 1 nanoroad. The calculated I V curves exhibit that the currents of the hybrid systems as a function of chemical derivation classes increase/decrease with different behavior, while they have similar behavior variations according to out layer strain. More interestingly, the calculated I V curves of hybrid b AFGANR 1 nanoroad system as a function of out layer strain exhibit negative differential resistance within bias voltage range 0.6 V to 1 V. Prime novelty statement In this paper, we investigate the effect of out layer strain on the electronic and transport properties of chemically functionalized hybrid b AGNR systems, which are formed by partial hydrogenation and fluorination (or hydrofluorination) in the middle parts of bilayer armchair graphene nanoribbon, using density functional theory and nonequilibrium Green's function techniques. The results present that all systems are structurally favorable and are semiconductors with band gaps of about 0.09 eV 1.55 eV as function of nanoroad width and out layer strain. Especially, the I V curves of hybrid b AFGANR 1 nanoroad system as a function of out layer strain exhibit negative differential resistance within bias voltage range 0.6 V to 1 V. The above results show that hybrid b AGNR systems would be a promising material for graphene based electronic devices.", "author_names": [ "Nam-Chol Ri", "Jong-Chol Kim", "Su-Il Ri" ], "corpus_id": 233590773, "doc_id": "233590773", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Improvement of the electronic and transport properties of hybrid bilayer armchair graphene nanoribbon by chemical derivation and out layer strain: A first principles calculations", "venue": "", "year": 2021 }, { "abstract": "A nanostructured porous carbon (NPC) is prepared by using a facile physical activation method, with nitrogen doped graphene nanoribbon aerogel and carbon dioxide as a precursor and an activating agent, respectively. The morphology, porosity parameters, and chemical properties of the as prepared NPC have been revealed by using various characterization methods, including scanning electron microscopy, nitrogen sorption analysis, and X ray photoelectron spectroscopy (XPS) The NPC with a moderate nitrogen content (5.1 atom on the basis of XPS analysis) retains the sponge like morphology of nitrogen doped graphene nanoribbon aerogel, shows a high Brunauer Emmett Teller specific surface area (1380 m2 g 1) and possesses hierarchically porous structures. Based on its excellent properties such as high porosity, conductive network, and nitrogen doping, NPC as a superior host is used to fabricate a sulfur based cathode for lithium sulfur batteries. The high specific surface area and the pore volume of NPC not only allow uniform distribution of sulfur in an amorphous form, but also help to alleviate the shuttle effect of polysulfides. As a result, the as obtained cathode exhibits a good rate capability and cycling stability.", "author_names": [ "Hang-Yu Zhou", "Zhuyin Sui", "Shan Liu", "Hai-Yan Wang", "Bao-Hang Han" ], "corpus_id": 59339689, "doc_id": "59339689", "n_citations": 20, "n_key_citations": 1, "score": 0, "title": "Nanostructured porous carbons derived from nitrogen doped graphene nanoribbon aerogels for lithium sulfur batteries.", "venue": "Journal of colloid and interface science", "year": 2019 }, { "abstract": "As the global energy consumption escalates at an alarming rate, the development of clean and renewable energy conversion technologies has become more critical. Solar energy is considered the ideal alternative, since it is the most readily available and richest renewable source of energy. Over the past few years, graphene, a two dimensional (2D) single atomic carbon sheet, has greatly contributed to many advances in solar energy conversion. However, the use of pure graphene alone is limited to the type of functions it can provide, not to mention the challenges that come with its processability. Therefore, the functionalization of graphene is essential for the development of solar specialized graphene based materials. This is achieved by typically integrating graphene into a photoactive material (e.g. semiconductors, organics, and metals) or, less commonly, by the self functionalization of graphene to render it photoactive. Overall, this chapter describes the versatility of functionalization to fabricate sophisticated graphene materials for solar energy conversion in three application categories photovoltaic, photochemical, and photoelectrochemical.", "author_names": [ "Lutfi Kurnianditia Putri", "Wee-Jun Ong", "Lling-Lling Tan", "Yi-Hao Chew", "Siang-Piao Chai" ], "corpus_id": 139232033, "doc_id": "139232033", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "CHAPTER 4:Functionalization of Chemically Derived Graphene for Solar Energy Conversion", "venue": "", "year": 2018 }, { "abstract": "Graphene oxide (GO) has unique physical, chemical, and mechanical properties. It has also acquired great interest for its unique mechanical, electrical, electronic, and optical properties. GO possesses different types of functional groups, which allows it to interact with organic and inorganic materials in covalent, non covalent, or ionic manner. Therefore, GO behaves like a semiconductor due the presence of impurity such as hydroxyl, carbonyl, and carboxyl groups as a functional group. The present paper deals with the synthesis of ultrathin layer of GO from commercially available graphite powder. The synthesis process starts with the chemical oxidation of commercial graphite powder into GO by modified Hummer's and Offeman method. Modified Hummer's method is simple and easily adoptable in laboratory. The obtained GO material was characterized by X ray diffraction (XRD) scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR)", "author_names": [ "Pankaj Kumar", "Neetu Divya", "Jatinder K Ratan" ], "corpus_id": 141230261, "doc_id": "141230261", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Synthesis and Characterization of Chemically Derived Graphene Oxide from Graphite", "venue": "", "year": 2019 }, { "abstract": "Summary The reticular synthesis of covalent organic frameworks (COFs) extended porous two dimensional (2D) or three dimensional (3D) networks held together by strong, highly directional chemical bonds, has thus far been restricted to small, shape persistent, molecular building blocks. Here, we demonstrate the growth of crystalline 2D COFs from a polydisperse macromolecule derived from single layer graphene, bottom up synthesized quasi one dimensional (1D) graphene nanoribbons (GNRs) X ray scattering and transmission electron microscopy reveal that 2D sheets of GNR COFs self assembled at a liquid liquid interface stack parallel to the layer boundary and exhibit an orthotropic crystal packing. Liquid phase exfoliation of multilayer GNR COF crystals gives access to large area >105 nm2) bilayer and trilayer cGNR COF films. The functional integration of extended 1D materials into crystalline COFs greatly expands the structural complexity and the scope of mechanical and physical materials properties accessible through a deterministic reticular bottom up approach.", "author_names": [ "Gregory Veber", "Christian S Diercks", "Cameron R Rogers", "Wade Scott Perkins", "Jim Ciston", "Kyunghoon Lee", "Juan Pablo Llinas", "Alex Liebman-Pelaez", "Chenhui Zhu", "Jeffrey Bokor", "Felix R Fischer" ], "corpus_id": 213046758, "doc_id": "213046758", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Reticular Growth of Graphene Nanoribbon 2D Covalent Organic Frameworks", "venue": "", "year": 2020 }, { "abstract": "At widths below 10 nm, armchair graphene nanoribbons become semiconductors. One promising route to synthesize nanoribbons is chemical vapor deposition (CVD) of hydrocarbons on Ge(001) and synthesis from seeds reduces nanoribbon polydispersity. In this contribution, we advance the seed initiated synthesis of nanoribbons and explore the impact of seed size and nanoribbon spacing on growth kinetics. Periodic arrays of graphene seeds are lithographically patterned and etched to reduce their diameter. The viability of initiating synthesis from sub 5 nm seeds is demonstrated, and the pitch between nanoribbons is reduced from 500 to 50 nm to show that crowding effects do not perturb nanoribbon growth kinetics. The invariance of kinetics with pitch in combination with density functional theory (DFT) calculations indicate: (1) the growth species for synthesis has a diffusion length 50 nm and/or (2) the kinetics are strongly attachment limited. These results demonstrate that seed initiated synthesis on Ge(001) is a promising route for creating dense arrays of armchair graphene nanoribbons for semiconductor electronics applications.", "author_names": [ "Austin J Way", "Ellen A Murray", "Florian Goltl", "Vivek Saraswat", "Robert M Jacobberger", "Manos Mavrikakis", "Michael S Arnold" ], "corpus_id": 195871314, "doc_id": "195871314", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Anisotropic Synthesis of Armchair Graphene Nanoribbon Arrays from Sub 5 nm Seeds at Variable Pitches on Germanium.", "venue": "The journal of physical chemistry letters", "year": 2019 }, { "abstract": "Label free sensors capable of detecting low concentrations of significant biomolecular substances without inducing immune response would simplify experiments, minimize errors, improve real time observations, and reduce costs in probing living organisms. This paper presents a first principles, in silico derived, all armchair graphene nanoribbon field effect transistor (g FET) device for the detection and measurement of low concentration (pM nM) uridine diphosphate glucose, UDP glucose. UDP glucose is an intermediate reactant in the synthesis of sucrose in a plant cell's cytoplasm and an extracellular signaling molecule capable of activating downstream defense mechanisms. The unique g FET configuration for the semiconducting channel and electrodes favors the fabrication of high density nanoarray sensors. Optimal device electronic transport and switching properties are predicted by screening configurations with different widths, to control bandgap, and lengths, to control thermionic versus tunneling transport across the semiconducting junction. A self assembled monolayer (SAM) of pyrene derivatives, 1 pyrenebutyric acid, is used to noncovalently functionalize the graphene surface on one end and to covalently ligate the target analyte on the other while providing mechanical, chemical, and electronic signal sensing stability. We find that the device offers a predicted limit of detection (LOD) of <italic>0.997</italic><inline formula> <tex math notation=\"LaTeX\"$n$ /tex math>/inline formula> mM/L (where <inline formula> <tex math notation=\"LaTeX\"$n$ /tex math>/inline formula> is the number of sensor units in an array) with high transconductance sensitivity, 0.75 <inline formula> <tex math notation=\"LaTeX\"$1.5\\mu \\text {S} /tex math>/inline formula> for 1 3 UDP glucose molecules, at low input <inline formula> <tex math notation=\"LaTeX\"$V_{G} 0.9$ /tex math>/inline formula> V) and output voltages <inline formula> <tex math notation=\"LaTeX\"$V_{\\text {DS}=0.1$ /tex math>/inline formula> V. Thus, a <inline formula> <tex math notation=\"LaTeX\"$1000\\times1000$ /tex math>/inline formula> nanoarray sensor would yield an LOD <italic>0.997</italic> nM/L. This low power, all armchair g FET sensor with SAM ligands that may be chosen to bind different biomarkers provides a unique opportunity for high throughput, real time, low cost, high mobility, and minimal calibration sensing applications.", "author_names": [ "Andres Jaramillo-Botero", "Juan M Marmolejo-Tejada" ], "corpus_id": 117569760, "doc_id": "117569760", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "All Armchair Graphene Nanoribbon Field Effect Uridine Diphosphate Glucose Sensor: First Principles In Silico Design and Characterization", "venue": "IEEE Sensors Journal", "year": 2019 }, { "abstract": "Three dimensional (3D) carbon aerogels with well defined structures, e.g. high specific surface area (SSA) appropriate pore size distribution, good electrical conductivity and ideal building blocks have been regarded as promising electrode materials or substrates for incorporated with pseudocapacitive materials for energy storage and conversion applications. Herein, we report a simple and scalable sonochemical method followed by chemical activation process to transform bacterial cellulose derived carbon nanofiber aerogels (CNFAs) into 3D graphene nanoribbon aerogels (GNRAs) for supercapacitors. Benefits from its high SSA, reasonable pore size distribution and good conductivity, the GNRAs electrodes demonstrate a long cyclability, good rate capability and high charge storage performance for supercapacitors, which yields more than 1.5 times (three electrode system) and 2.6 times (two electrode system) of gravimetric capacitance compared to the CNFAs electrode. In addition, a hybrid Ni Co layered double hydroxides (LDHs)@GNRAs electrode achieves an impressive gravimetric capacitance of 968 F g 1 (based on the mass of the active material) at a current density of 1 A g 1. Moreover, an asymmetric supercapacitors (ASCs) device with a remarkable energy density of 29.87 Wh kg 1, wide working voltage windows of 1.6 V and good cycling stability (63.5% retention after 10,000 cycles) is achieved by using the GNRAs as anode and the Ni Co LDHs@GNRAs as cathode.", "author_names": [ "Liujun Cao", "Lifei Liu", "Xuejing Chen", "Man Huang", "Xue Wang", "Jianping Long" ], "corpus_id": 208040710, "doc_id": "208040710", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Scalable syntheses of three dimensional graphene nanoribbon aerogels from bacterial cellulose for supercapacitors.", "venue": "Nanotechnology", "year": 2019 } ]

[ { "abstract": "Cuprous oxide (Cu2O) is a promising earth abundant semiconductor for photovoltaic applications. Developing an understanding of the p type conduction mechanism is vital to optimize the material. We have used a reactive magnetron sputtering system to fabricate Cu2O thin films. The bandgap, refractive index, mobility, density of hole, and electrical conductivity in the films have also been investigated. Our work shows that the films fabricated under nitrogen rich condition exhibit wide bandgaps and low electrical conductivities while the films deposited under oxygen rich condition have narrow bandgaps and high electrical conductivities. The results from the density functional theory are introduced to explain the gas dependence of the bandgap. A developed theoretical model based on Fermi Dirac statistics shows that the high electrical conductivities originate from the acceptor levels located below Feimi level in the film.", "author_names": [ "Liangmin Zhang", "Lyndsey B McMillon", "Jeremiah S Mcnatt" ], "corpus_id": 97701799, "doc_id": "97701799", "n_citations": 28, "n_key_citations": 0, "score": 1, "title": "Gas dependent bandgap and electrical conductivity of Cu2O thin films", "venue": "", "year": 2013 }, { "abstract": "Hall effect and electrical conductivity measurements were performed on Cu2O single crystals both before and after heating the samples in vacuo at temperatures ranging from 200 degC to 800 degC. Both th.", "author_names": [ "Emery Fortin", "Frank L Weichman" ], "corpus_id": 122168038, "doc_id": "122168038", "n_citations": 54, "n_key_citations": 1, "score": 1, "title": "HALL EFFECT AND ELECTRICAL CONDUCTIVITY OF Cu2O MONOCRYSTALS", "venue": "", "year": 1966 }, { "abstract": "Dy Cu intermediate alloys have shown substantial potential in the field of magnetostrictive and magnetic refrigerant materials. Therefore, this study focused on investigating the electrical conductivity of molten salt systems for the preparation of Dy Cu alloys and on optimizing the corresponding operating parameters. The electrical conductivity of molten LiF DyF3 Dy2O3 Cu2O systems was measured from 910 to 1030degC using the continuously varying cell constant method. The dependencies of the LiF DyF3 Dy2O3 Cu2O system conductivity on the melt composition and temperature were examined herein. The optimal operating conditions for Dy Cu alloy production were determined via analyses of the electrical conductivity and activation energies for conductance, which were calculated using the Arrhenius equation. The conductivity of the molten system regularly increases with increasing temperature and decreases with increasing concentration of Dy2O3 or Cu2O or both. The activation energy Ek of the LiF DyF3 Dy2O3 and LiF DyF3 Cu2O molten salt systems increases with increasing Dy2O3 or Cu2O content. The regression functions of conductance as a function of temperature (t) and the addition of Dy2O3 (W(Dy2O3) and Cu2O (W(Cu2O) can be expressed as k 2.08435 0.0068t 0.18929W(Dy2O3) 0.07918W(Cu2O) The optimal electrolysis conditions for preparing the Dy Cu alloy in LiF DyF3 Dy2O3 Cu2O molten salt are determined to be 2.0wt% W(Dy2O3) W(Cu2O) 3.0wt% and W(Dy2O3) W(Cu2O) 1:2 at 970 to 1000 degC.", "author_names": [ "Shu-mei Chen", "Chunfa Liao", "Jue-yuan Lin", "Bo-qing Cai", "Xu Dong Wang", "Yun-fen Jiao" ], "corpus_id": 195219640, "doc_id": "195219640", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Electrical conductivity of molten LiF DyF3 Dy2O3 Cu2O system for Dy Cu intermediate alloy production", "venue": "International Journal of Minerals, Metallurgy and Materials", "year": 2019 }, { "abstract": "The acknowledgements of this article unfortunately contained a mistake. The grant number of the National Natural Science Foundation of China was incorrect.", "author_names": [ "Shu-mei Chen", "Chunfa Liao", "Jue-yuan Lin", "Bo-qing Cai", "Xu Wang", "Yun-fen Jiao" ], "corpus_id": 210168673, "doc_id": "210168673", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Erratum to: Electrical conductivity of molten LiF DyF3 Dy2O3 Cu2O system for Dy Cu intermediate alloy production", "venue": "International Journal of Minerals, Metallurgy and Materials", "year": 2020 }, { "abstract": "This work aims at investigating the conversion of Cu2O/Cu nanoparticles, prepared by green synthesis using artichoke extract, with ascorbic acid (AA) in one bath process: a totally green method for production of pure Cu particles. Different pH values of the solution were studied to assess the conversion to Cu phase particles. It was found that by using the optimum synthesis conditions for the production of Cu2O/Cu nanoparticles and adding at the end of the synthesis AA, the conversion of Cu2O phase to pure Cu phase was possible when the pH of the solution was 8 or 10, but not when it was 12. The size of particles increased from nano to micron sized after adding AA and multi shaped particles with spherical, triangular, cubical and rod like shapes were formed, depending upon the pH of the synthesis solution. The electrical resistivity of the obtained pure Cu microparticles was studied after low temperature sintering at different times and after preparing compact powder discs. After sintering for 30 min at 180 degC, discs showed resistivity of 2.9 x 10 3 Ocm and after sintering for 60 min at 180 degC the resistivity lowered to 5.1 x 10 4 Ocm. It can be concluded that the low resistivity of powder discs mainly depended on the size of Cu particles and sintering time, when using a fixed sintering temperature. The present synthesis of pure Cu phase microparticles is simple, convenient, environmentally friendly, cost effective, it does not use inert gases, it is performed in aqueous media and the produced Cu particles are suitable for low electrical resistivity applications.", "author_names": [ "Sandra Sampaio", "Julio C Viana" ], "corpus_id": 235434399, "doc_id": "235434399", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Green synthesis of Cu2O/Cu nanoparticles and conversion to Cu microparticles in one bath reaction method for improved electrical conductivity", "venue": "", "year": 2021 }, { "abstract": "It is interesting to examine facet dependent electrical properties of single Cu2O crystals, because such study greatly advances our understanding of various facet effects exhibited by semiconductors. We show a Cu2O octahedron is highly conductive, a cube is moderately conductive, and a rhombic dodecahedron is nonconductive. The conductivity differences are ascribed to the presence of a thin surface layer having different degrees of band bending. When electrical connection was made on two different facets of a rhombicuboctahedron, a diode like response was obtained, demonstrating the potential of using single polyhedral nanocrystals as functional electronic components. Density of state (DOS) plots for three layers of Cu2O (111) (100) and (110) planes show respective metallic, semimetal, and semiconducting band structures. By examining DOS plots for varying number of planes, the surface layer thicknesses responsible for the facet dependent electrical properties of Cu2O crystals have been determined to be below 1.5 nm for these facets.", "author_names": [ "Chih-Shan Tan", "S C Hsu", "Wei-Hong Ke", "Lih-Juann Chen", "Michael H Huang" ], "corpus_id": 5604916, "doc_id": "5604916", "n_citations": 128, "n_key_citations": 0, "score": 1, "title": "Facet dependent electrical conductivity properties of Cu2O crystals.", "venue": "Nano letters", "year": 2015 }, { "abstract": "Temperature dependent Hall effect and resistivity measurements are performed on polycrystalline Cu2O:Sr thin films deposited on glass substrate by metal organic chemical vapor deposition. Their electrical properties are studied as a function of the strontium content, as determined by wavelength dispersive X ray spectrometry. These electrical transport measurements highlight a copper vacancy doping mechanism induced by strontium incorporation, leading to a large decrease of the resistivity as low as 1.2 O*cm and corresponding free carrier mobilities about 15 cm2*V 1*s 1 at room temperature. Moreover, in addition to the main copper vacancy acceptor level, found at EA1 278 21 meV above the top of the valence band, a coexisting shallower acceptor level with an ionization energy of EA2 133 15 meV occurs for a strontium content above 5% and is tentatively assigned to a large size impurity vacancy complex.", "author_names": [ "Stephane Brochen", "Laurent Bergerot", "Wilfried Favre", "Joao Resende", "Carmen Jimenez", "Jean Luc Deschanvres", "Vincent Consonni" ], "corpus_id": 102359993, "doc_id": "102359993", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Effect of Strontium Incorporation on the p Type Conductivity of Cu2O Thin Films Deposited by Metal Organic Chemical Vapor Deposition", "venue": "", "year": 2016 }, { "abstract": "Boron doped cuprous oxide (Cu2O:B) thin films were deposited on glass and silicon substrates via radio frequency (rf) magnetron co sputtering at room temperature using metallic copper and boron targets. The influence of B doping on the morphology of Cu2O was studied using X ray diffraction and spectrometric techniques. Optical transparency and bandgap of the doped films were improved compared to intrinsic Cu2O thin film. X ray photoelectron spectroscopy confirms that Cu is in 1 valance state even after doping. Electrical characteristics suggest enhanced p type conductivity and reduction in resistivity with boron doping, due to the increase in charge carriers. Cu2O:B/c Si heterojunction shows good rectifying 104) behavior, and the small Ev and high Ec obtained from the flat band diagram suggests its potential application as hole selective layer in c Si solar cell.", "author_names": [ "Manu Shaji", "Kurias K Markose", "K J Saji", "M K Jayaraj" ], "corpus_id": 218864728, "doc_id": "218864728", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Investigation on the improved electrical and optical properties of trivalent boron doped Cu2O thin film and fabrication of Cu2O:B/c Si heterojunction diode", "venue": "Journal of Materials Science: Materials in Electronics", "year": 2020 }, { "abstract": "A series of conductivity measurements were made on single crystals of Cu2O from 20 to 840 degC to explain the various activation energies which appear at different temperatures and oxygen pressures.", "author_names": [ "Frank L Weichman", "Radomir Kuzel" ], "corpus_id": 122385147, "doc_id": "122385147", "n_citations": 22, "n_key_citations": 0, "score": 1, "title": "Influence of annealing on the electrical conductivity of single crystals of Cu2O", "venue": "", "year": 1970 }, { "abstract": "Abstract Sphere like Cu Cu2O nanoparticles on graphene nanoplatelets (Cu Cu2O@GNP) nanocomposites were prepared via the in situ decomposition of copper acetate and GNP at 500 degC in N2 flow. The thermal behavior of the copper acetate and GNP mixtures was monitored using thermogravimetric analysis (TGA) X ray diffraction (XRD) X ray photoelectron spectroscopy (XPS) field emission scanning electron microscopy (FE SEM) transmission electron microscopy (TEM) and N2 adsorption were used to characterize the obtained nanocomposites. The obtained results revealed that the nanocomposites are consisted of Cu Cu2O nanospheres distributed among the graphene nanoplatelets. The study on the thermal effect of cyclic conductivity was done on Cu Cu2O@GNP in the pure form, prepared in different copper loadings (5% 10% 20% and 30% The dc conductivity for 5% 10% 20% and 30% of Cu Cu2O@GNP composite was found 42.44 S cm 1, 44.053 S cm 1, 75.42 S cm 1 and 78.951 S cm 1, respectively measured by 4 in line probe dc electrical conductivity measuring technique. This shows the metallic behavior as it increasing with the temperature and highest ratio of metal have high conductivity.", "author_names": [ "Bahaa M Abu-Zied", "Mahmoud Ali Hussein", "Anish Khan", "Abdullah M Asiri" ], "corpus_id": 103025005, "doc_id": "103025005", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Cu Cu2O@graphene nanoplatelets nanocomposites: Facile synthesis, characterization, and electrical conductivity properties", "venue": "", "year": 2018 } ]

[ { "abstract": "High index dielectric and semiconductor nanoparticles supporting strong electric and magnetic resonances have drawn significant attention in recent years. However, until now, there have been no experimental reports of lasing action from such nanostructures. Here, we demonstrate directional lasing, with a low threshold and high quality factor, in active dielectric nanoantenna arrays achieved through a leaky resonance excited in coupled gallium arsenide (GaAs) nanopillars. The leaky resonance is formed by partially breaking a bound state in the continuum generated by the collective, vertical electric dipole resonances excited in the nanopillars for subdiffractive arrays. We control the directionality of the emitted light while maintaining a high quality factor (Q 2,750) The lasing directivity and wavelength can be tuned via the nanoantenna array geometry and by modifying the gain spectrum of GaAs with temperature. The obtained results provide guidelines for achieving surface emitting laser devices based on active dielectric nanoantennas that are compact and highly transparent.Active dielectric nanoantenna arrays exhibit low threshold and high quality factor directional lasing achieved via a leaky resonance excited in coupled gallium arsenide (GaAs) nanopillars.", "author_names": [ "Son Tung Ha", "Yuan Hsing Fu", "Naresh Kumar Emani", "Zhenying Pan", "Reuben M Bakker", "Ramon Paniagua-Dominguez", "Arseniy I Kuznetsov" ], "corpus_id": 52049890, "doc_id": "52049890", "n_citations": 187, "n_key_citations": 1, "score": 1, "title": "Directional lasing in resonant semiconductor nanoantenna arrays", "venue": "Nature Nanotechnology", "year": 2018 }, { "abstract": "Direct printing of semiconductor nanoparticles via laser induced transfer is a recently developed tool to obtain individual nanoparticles or their arbitrary arrays on a substrate of almost any shape and material. Semiconductor nanoparticles supporting Mie resonance are now widely explored in the pursuit for the novel all dielectric photonic platforms. The promising direction is merging Mie resonant nanoparticles with photonic crystals. We experimentally demonstrate excitation of a Bloch surface wave in photonic crystal mediated by an individual silicon nanoparticle. The nanoparticle being irradiated by light with the wavelength near the Mie resonance acts as a nanoantenna and allows excitation of the Bloch surface wave from the far field. Visualization of the surface wave propagation direction is performed by the Fourier plane imaging using the leakage radiation microscopy setup. We show that tuning the wavelength of the incident light around the Mie resonance allows for launching Bloch surface wave in both forward and backward direction.", "author_names": [ "Boris I Afinogenov", "Natalia G Kokareva", "Dmitry N Gulkin", "Daniil A Shilkin", "Denis Zhigunov", "Vladimir O Bessonov", "Andrey A Fedyanin" ], "corpus_id": 221910771, "doc_id": "221910771", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Directional excitation of Bloch surface waves by laser printed Mie nanoparticles", "venue": "NanoScience Engineering", "year": 2020 }, { "abstract": "A highly efficient nanocavity formed by optically coupled nanostructures is achieved by optimization of the collective Mie resonances in a one dimensional array of semiconductor nanoparticles. Analysis of quasi normal multipole modes enables us to reveal the close relation between the collective Mie resonances and Van Hove singularities. Based on these concepts, we experimentally demonstrate a directional GaAs nanolaser at cryogenic temperatures with well defined, in plane emission, which, moreover, can be controlled by selective excitation. The lasing threshold is shown to be significantly reduced by optimizing the inter particle gap such that the optimal near field confinement is achieved at a resonant wavelength corresponding to the highest gain of GaAs. We show that the lasing performance of this nanolaser is orders of magnitude better than a nanowire based laser of the same dimensions. The present work provides design guidelines for high performance in plane emission nanolasers, which may find applications in future photonic integrated circuits.", "author_names": [ "Thanh Xuan Hoang", "Son Tung Ha", "Zhenying Pan", "Wee Kee Phua", "Ramon Paniagua-Dominguez", "Ching Eng Png", "Hong-Son Chu", "Arseniy I Kuznetsov" ], "corpus_id": 220289267, "doc_id": "220289267", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Collective Mie Resonances for Directional On chip Nanolasers.", "venue": "Nano letters", "year": 2020 }, { "abstract": "Metasurfaces composed of designed Mie resonant semiconductor nanoparticles offer unique opportunities for controlling the properties of light fields transmitted through them or reflected from them [1] Such metasurfaces can e.g. impose a spatially variant phase shift onto an incident light field, thereby providing control over its wave front with high transmittance efficiency [2] However, most semiconductor metasurfaces realized so far were passive and linear, and their optical response was permanently encoded into the structure during fabrication. Recently, a growing amount of research is concentrated on the integration of emitters and optical nonlinearities into semiconductor metasurfaces and on obtaining dynamic control of their optical response. This talk will provide an overview of our recent advances in active, nonlinear, and tunable Mie resonant semiconductor metasurfaces. In particular, we have studied spontaneous emission from metasurfaces incorporating various types of emitters, including semiconductor quantum dots, monolayers of transition metal dichalcogenides, and fluorescent centers in the substrate. For emission frequencies below or near the fundamental electronic bandgap of the respective semiconductor material, the individual Mie resonant metasurface building blocks can provide the functionality of dielectric nanoantennas, and exhibit high directivity, Purcell enhancement, and near unity radiation efficiencies [3,4] Consequently, we may understand an active metasurface as a two dimensional array of resonant dielectric nanoantennas, which are excited by localized emitters that are located in their vicinity. In order to characterize the emission properties of our active metasurfaces, we perform micro photoluminescence imaging, spectroscopy, and Fourier imaging for a variety of different active metasurface architectures. Our results show that the directional and spectral properties of the emitted light can be tailored by the metasurface design. Using nonlinear Fourier imaging, we have also investigated second harmonic generation in metasurfaces composed of III V semiconductors. We show that the generated second harmonic signal depends sensitively on the polarization of the pump field. For dynamic tuning of the metasurface response, we make use of the strong spectral dispersion associated with the resonant optical response of the metasurfaces in combination with the sensitivity of the resonance properties on the dielectric environment of the individual nanoresonators. Specifically, by integrating a silicon metasurface into a nematic liquid crystal cell, we have demonstrated dynamic tuning of the metasurface linear optical response using an applied voltage as control parameter [5] Finally, by combining resonance tuning based on liquid crystals with spontaneous emission enhancement by Mie type resonances, we have achieved dynamic control of the emission from an active metasurface consisting of silicon nanoresonators coupled to a fluorescent substrate. [1] I. Staude J. Schilling, Nature Photon. 11, 274 284 (2017) [2] K. E. Chong et al. Nano Lett. 15, 5369 5374 (2015) [3] A. E. Krasnok et al. Opt. Exp. 20, 20599 (2012) [4] X. Zambrana Puyalto N. Bonod, Phys. Rev. B 91, 195422 (2015) [5] A. Komar et al. Appl. Phys. Lett. 110, 071109 (2017)", "author_names": [ "Isabelle Staude" ], "corpus_id": 139780152, "doc_id": "139780152", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Active, nonlinear, and tunable Mie resonant semiconductor metasurfaces (Conference Presentation)", "venue": "", "year": 2018 }, { "abstract": "We demonstrate experimentally and describe theoretically the strong directional emission and absorption of light by III V semiconductor nanowires mediated by the resonant coupling to guided and leaky modes in the cylindrical structure. The absorption and emission of light can be modified and enhanced by its resonant interaction with nanostructures, such as semiconductor nanowires. Nanowires are characterized by a lateral dimension comparable to the wavelength of light and a much larger length, which enables their resonant interaction with light and the guiding of electromagnetic waves. Here, we demonstrate experimentally and describe theoretically the strong directional emission and absorption of light by III V semiconductor nanowires mediated by the resonant coupling to guided and leaky modes in the cylindrical structure. The coupling to these eigenmodes of the nanowires depends strongly on their diameter and length, which opens a rich spectrum of possibilities for the control of the direction, efficiency and polarization of the emission and absorption of light [1] The emission experiments have been performed with a Fourier microscope [2 4] i.e. by imaging the back focal plane of a microscope objective to map the emission of single nanowires and of nanowire arrays. We also introduce a technique termed time reversed Fourier microscopy, which enables the detection of the directional absorption of polarized light by individual nanowires [5] This techniques consists on focusing and scanning a laser beam at the back focal plane of the microscope objective. In this way, a sample under the objective is illuminated by a plane wave at an angle of incidence that is scanned to retrieve a map of the angular dependent absorption. Semiconductor nanowires behave as small optical antennas that are able to emit and absorb light in and from defined directions and polarizations. These directions and the polarization of the light are mostly determined by the nanowire diameter. In order to increase the possibilities for directional emission from individual nanowires, we have introduced hybrid nanowire plasmonic antennas[6] In these structures, the emission from a nanowire is scattered by metallic nanorods resonant at the emission wavelength. These rods are plasmonic resonantors that are placed at defined locations to achieve constructive interference of the emission in certain directions. In this way, we have demonstrated an hybrid nanowire plasmonic Yagi Uda nanoantenna with beamed emission. This device is illustrated in the figure below.", "author_names": [ "Jaime Gomez Rivas" ], "corpus_id": 114391363, "doc_id": "114391363", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The nanowire optical antenna: Controlled directional emission and absorption of light by semiconductor nanowires", "venue": "SUM 2016", "year": 2016 }, { "abstract": "This thesis investigates the control of light via isolated nanoparticles of gold or III V semiconductor gallium phosphide. Nanoscale control of light has a range applications in on chip devices and optoelectric interfacing, where large arrays of nanoparticles are not always practical. Simulations, performed using the Boundary Element Method, show semiconductor nanorods to function as two dimensional cavities, bridging the gap between more commonly used analytical models for a sphere and an infinite cylinder. Dimer structures, made of two nanorods placed end to end, are shown to enhance the electric ?eld in the center of the gap, comparable to gold structures of similar design. Experiments, however, show these effects to be elusive. Further simulation using the Finite Element Method indicates that these structures also demonstrate highly directional reradiation of the incident field. Gold nanoantennas were investigated for their interaction with a phase change material and light carried within a wavguide with the aim of producing an all optical modulation device. A film of phase change material is shown to be able to rapidly and reversibly modulate the response of a gold nanoantenna. An antenna on top of a rib waveguide is shown to aid in the modulation of a carrier pulse by use of a second pump pulse.", "author_names": [ "Daniel Traviss" ], "corpus_id": 135987603, "doc_id": "135987603", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Control of light via individual resonant nanoparticle devices", "venue": "", "year": 2016 }, { "abstract": "The use of geometrical constraints exposes many new perspectives in photonics and in the fundamental studies of nonlinear waves. By implementing surface structures in vertical cavity surface emitting lasers as manifolds for curved space, we experimentally study the impacts of geometrical constraints on nonlinear wave localization. We observe localized waves pinned to the maximal curvature in an elliptical ring, and confirm the reduction in the localization length of waves by measuring near and far field patterns, as well as the corresponding energy angle dispersion relation. Theoretically, analyses based on a dissipative model with a parabola curve give good agreement remarkably to experimental measurement on the reduction in the localization length. The introduction of curved geometry allows to control and design lasing modes in the nonlinear regime. (c) 2017 Optical Society of America OCIS codes: (240.6690) Surface waves; (240.0240) Optics at surfaces; (140.7260) Vertical cavity surface emitting lasers; (140.3948) Microcavity devices. References and links 1. J. W. S. Rayleigh, The Theory of Sound (Macmillan, 1894) 2. C. Barcelo, S. Liberati, and M. Visser, \"Probing semiclassical analog gravity in Bose Einstein condensates with widely tunable interactions,\" Phys. Rev. A 68, 053613 (2003) 3. Th. G. Philbin, C. Kuklewicz, S. Robertson, S. Hill, F. Konig, U. Leonhardt, \"Fiber optical analog of the event horizon,\" Science 319, 1367 (2008) 4. D. Faccio, T. Arane, M. Lamperti, and U. Leonhardt, \"Optical black hole lasers,\" Class. Quantum Grav. 29, 224009 (2012) 5. C. Conti, \"Linear and nonlinear Anderson localization in a curved potential,\" Chin. Phys. Lett. 31, 30501 (2014) 6. N. Ghofraniha, I. Viola, A. Zacheo, V. Arima, G. Gigli, and C. Conti \"Transition from nonresonant to resonant random lasers by the geometrical confinement of disorder,\" Opt. Lett. 38, 5043 (2013) 7. U. Leonhardt, \"Optical conformal mapping,\" Science 312, 1777 (2006) 8. J. B. Pendry, D. Schurig, and D. R. Smith, \"Controlling electromagnetic fields,\" Science 312, 1780 (2006) 9. D. A. Genov, S. Zhang, and X. Zhang, \"Mimicking celestial mechanics in metamaterials,\" Nat. Phys. 5, 687 (2009) 10. A. Paredes, and H. Michinel, \"Interference of dark matter solitons and galactic offsets,\" Phys. Dark. Univ. 12, 50 (2016) 11. S. Batz, and U. Peschel, \"Linear and nonlinear optics in curved space,\" Phys. Rev. A 78, 043821 (2008) 12. S. Batz, and U. Peschel, \"Solitons in curved space of constant curvature,\" Phys. Rev. A 81, 053806 (2010) 13. R. Bekenstein, J. Nemirovsky, I. Kaminer, and M. Segev, \"Shape preserving accelerating electromagnetic wave packets in curved space,\" Phys. Rev. X 4, 011038 (2014) 14. W. Wan, S. Jia, and J. W. Fleisher, \"Dispersive superfluid like shock waves in nonlinear optics,\" Nat. Phys. 3, 46 (2007) 15. C. Conti, \"Localization and shock waves in curved manifolds for the Gross Pitaevskii equation,\" Sci. Bull. 61, 570 (2016) 16. V. H. Schultheiss, S. Batz, A. Szameit, F. Dreisow, S. Nolte, A. Tunnermann, S. Longhi, and U. Peschel, \"Optics in curved space,\" Phys. Rev. Lett. 105, 143901 (2010) 17. Yu. S. Kivshar and G. P. Agrawal, Optical Solitons: from Fibers to Photonic Crystals (Academic, 2003) Vol. 25, No. 23 13 Nov 2017 OPTICS EXPRESS 29068 #306536 https:/doi.org/10.1364/OE.25.029068 Journal (c) 2017 Received 5 Sep 2017; revised 4 Nov 2017; accepted 5 Nov 2017; published 8 Nov 2017 18. A. Sacchetti, \"Universal Critical Power for Nonlinear Schrodinger Equations with a Symmetric DoubleWell Potential,\" Phys. Rev. Lett. 103, 194101 (2009) 19. S. Barland, J. R. Tredicce, M. Brambilla, L. A. Lugiato, S. Balle, M. Giudici, T. Maggipinto, L. Spinelli, G. Tissoni, T. Knodl, M. Miller, and R. Jager, \"Cavity solitons as pixels in semiconductor microcavities,\" Nature 419, 699 (2002) 20. R. K. Chang and A. J. Campillo, eds. Optical Processes in Microcavities (World Scientific, 1996) 21. K. J. Vahala, Optical Microcavities, (World Scientific, 2004) 22. Y. Tanguy, T. Ackemann, W. J. Firth, and R. Jager, \"Realization of a semiconductor based cavity soliton laser,\" Phys. Rev. Lett. 100, 013907 (2008) 23. T. D. Lee, C. Y. Chen, Y.Y. Lin, M. C. Chou, T. h. Wu, and R. K. Lee, \"Surface structure assisted chaotic mode lasing in vertical cavity surface emitting lasers,\" Phys. Rev. Lett. 101, 084101 (2008) 24. K. H. Kuo, Y.Y. Lin, and R. K. Lee, \"Thresholdless crescent waves in an elliptical ring,\" Opt. Lett. 38, 1077 (2013) 25. Y. V. Kartashov, V. A. Vysloukh, and L. Torner, \"Rotating surface solitons,\" Opt. Lett. 32, 2948 (2007) 26. C.P. Jisha, Y.Y. Lin, T. D. Lee, and R. K. Lee, \"Crescent waves in optical cavities,\" Phys. Rev. Lett. 107, 183902 (2011) 27. D. L. Huffaker, H. Deng, Q. Deng, and D. G. Deppe, \"Ring and stripe oxide confined vertical cavity surface emitting lasers,\" Appl. Phys. Lett. 69, 3477 (1996) 28. J. Scheuer, M. Orenstein, and D. Arbel, \"Nonlinear switching and modulational instability of wave patterns in ring shaped vertical cavity surface emitting lasers,\" J. Opt. Soc. Am. B 19, 2384 (2002) 29. J. W. Shi, C. H. Jiang, K. M. Chen, J. L. Yen, and Y. J. Yang, \"Single mode vertical cavity surface emitting laser with ring shaped light emitting aperture,\" Appl. Phys. Lett. 87, 031109 (2005) 30. Y. Y. Lin and R. K. Lee, \"Symmetry breaking instabilities of generalized elliptical solitons,\" Opt. Lett. 33, 1377 (2008) 31. M. A. Bandres and J. C. Gutierrez Vega, \"Ince Gaussian modes of the paraxial wave equation and stable resonators,\" J. Opt. Soc. Am. A 21, 873 (2004) 32. A. Kroner, F. Rinaldi, J. M. Ostermann, R. Michalzik, \"High performance single fundamental mode AlGaAs VCSELs with mode selective mirror reflectivities,\" Opt. Commun. 270, 332 (2007) 33. M. Brambilla, L. A. Lugiato, F. Prati, L. Spinelli, and W. J. Firth, \"Spatial soliton pixels in semiconductor devices,\" Phys. Rev. Lett. 79, 2042 (1997) 34. W. X. Yang, Y.Y. Lin, T. D. Lee, R. K. Lee, and Yu. S. Kivshar, \"Nonlinear localized modes in bandgap microcavities,\" Opt. Lett. 35, 3207 (2010) 35. C. H. Henry, R. A. Logan, and K. A. Bertness, \"Spectral dependence of the change in refractive index due to carrier injection in GaAs lasers,\" J. Appl. Phys. 52, 4457 (1981) 36. G. R. Olbright, R. P. Bryan,W. S. Fu, R. Apte, D.M. Bloom, andY. H. Lee, \"Linewidth, tunability, and VHF millimeter wave frequency synthesis of vertical cavity GaAs quantum well surface emitting laser diode arrays,\" IEEE Photonics Technol. Lett. 3, 779 (1991) 37. D. V. Kuksenkov, H. Temkin, and S. Swirhun, \"Frequency modulation characteristics of gain guided AlGaAs/GaAs vertical cavity surface emitting lasers,\" Appl. Phys. Lett. 66, 3239 (1995)", "author_names": [ "", "B", "C -", "H -", "Y -", "M", "L -", "K -" ], "corpus_id": 201032173, "doc_id": "201032173", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Lasing on nonlinear localized waves in curved geometry", "venue": "", "year": 2017 }, { "abstract": "DOI: 10.1002/adom.201800664 limit, and may also serve to enhance and direct the emission from local sources. In both regards, the antennas act as a crucial bridge between the electromagnetic radiation in the farand near field regions, and have recently attracted considerable attention.[1] Metal based nanoantennas, composed of materials such as silver and gold, harness the properties of plasmonic excitations to control light on the nanoscale, opening up many opportunities within areas such as telecommunications, sensing, and photovoltaics.[2 4] The plasmonic response of such nanoantennas stems from the collective oscillation of electrons,[5] which enables significant enhancement of the electric near field, whereas the magnetic near field is not considerably affected. However, the inherent ohmic loss associated with plasmonic excitations gives rise to Joule heating and, as a result, their use in temperature sensitive applications, such as surface enhanced Raman spectroscopy, might be hindered.[6,7] By contrast, all dielectric and semiconductor nanoantennas composed of high index materials in a low index background may support both electric and magnetic Mie type resonances, therefore facilitating significant field confinement whilst maintaining low losses across the visible and near infrared spectral regions.[8 13] These dielectric or semiconductor nanoantennas confine fields within the volume of the structure, which results in lower field confinement compared to their metallic counterparts, but also allows for a greater effective interaction volume between the incident field and the bulk material in, for example, nonlinear processes.[6] All dielectric nanophotonic technology can be readily employed in lossand temperature sensitive applications.[14] Moreover, interplay between electric and magnetic resonances in these nanoantennas provides a means of engineering the directionality of scattering and second harmonic generation.[15 18] Consequently, arrays of dielectric nanoantennas represent a promising route toward low loss metamaterials and metasurfaces,[16,19,20] in addition to nanoscale photodiodes.[21] Moreover, destructive interference between two different dipole moments in nanoscale antennas may lead to nonradiative anapole modes.[22,23] Importantly, dielectric nanoantennas are suitable for engineering nonlinear optical effects if they are composed of materials with a high nonlinear susceptibility, such as GaAs[24] and AlGaAs.[6] All dielectric nanoantennas enable the manipulation and confinement of light on the nanoscale through a variety of resonant excitations. Understanding and controlling the interactions among resonances at a level of individual nanoantennas is required for the development of appropriate design rules for their applications, especially with regard to nonlinear optics, where the nonlinear interaction depends on the resonant behavior in a superlinear manner. Here, cathodoluminescence imaging spectroscopy is used to experimentally investigate the electric and magnetic modes supported by single AlGaAs nanoantennas and their hybridization in a dimer configuration. An interplay is shown between the resonant modes of the nanostructures and interband emission of the semiconductor material, which contrasts with Si nanoantennas, where the bandgap effects are not significant. The measurements are in very good agreement with numerical simulations, which also provided further insight into the nature of the modes. The resonant modes of semiconductor nanoantennas are important for engineering linear and nonlinear metasurfaces, as well as for sensing applications and fluorescence control in nanophotonic environments.", "author_names": [ "Cillian P T McPolin", "Giuseppe Marino", "Alexey V Krasavin", "Valerio Flavio Gili", "Luca Carletti", "Costantino De Angelis", "Giuseppe Leo", "Anatoly V Zayats" ], "corpus_id": 105825887, "doc_id": "105825887", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Imaging Electric and Magnetic Modes and Their Hybridization in Single and Dimer AlGaAs Nanoantennas", "venue": "", "year": 2018 }, { "abstract": "Optical properties of two dimensional periodic system of the silicon micro cones are investigated. The metasurface, composed of the silicon tips, shows enhancement of the local optical field. Finite element computer simulations as well as real experiment reveal anomalous optical response of the dielectric metasurface due to excitation of the dielectric resonances. Various electromagnetic resonances are considered in the dielectric cone. The metal dielectric resonances, which are excited between metal nanoparticles and dielectric cones, are also considered. The resonance local electric field can be much larger than the field in the usual surface plasmon resonances. To investigate local electric field the signal molecules are deposited on the metal nanoparticles. We demonstrate enhancement of the electromagnetic field and Raman signal from the complex of DT NB acid molecules and gold nanoparticles, which are distributed over the metasurface. The metasurfaces composed from the dielectric resonators can have quasi continuous spectrum and serve as an efficient SERS substrates. (c) 2017 Optical Society of America OCIS codes: (260.0260) Physical optics; (240.0240) Optics at surfaces; (240.6695) Surface enhanced Raman Scattering. References and links 1. K. J. Vahala, \"Optical microcavities,\" Nature 424, 839 846 (2003) 2. T. Aoki, B. Dayan, E. Wilcut, W. Bowen, A. Parkins, T. Kippenberg, K. Vahala, and imble, \"Observation of strong coupling between one atom and a monolithic micro resonator,\" Nature 443, 671 674 (2006) 3. B. Min, E. Ostby, V. Sorger, E. Ulin Avila, L. Yang, X. Zhang, and K. Vahala, \"High Q surface plasmon polariton whispering gallery microcavity,\" Nature 457, 455 458 (2009) 4. H. Tureci, H. Schwefe, P. Jacquod, and D. Stone, \"Modes of wave chaotic dielectric resonators,\" Progress in Optics 47, 75 108 (2005) 5. L. Rayleigh, \"The problem of whispering gallery,\" Phil. Mag. 20, 1001 1004 (1904) 6. D. K. Armani, T. J. Kippenberg, S. M. Spillane, and K. J. Vahala, \"Ultra high Q toroid microcavity on a chip,\" Nature 421, 925 928 (2003) 7. T. Herr, V. Brasch, J. D. Jost, I. Mirgorodskiy, G. Lihachev, M. L. Gorodetsky, and T. J. Kippenberg, \"Mode spectrum and temporal soliton formation in optical microresonators,\" Phys. Rev. Lett. 113, 123901 5 (2014) 8. A. A. Savchenkov, A. B. Matsko, V. S. Illchenko, and L. Maleki, \"Optical resonators with ten million nesse,\" Opt. Express 15, 6768 6773 (2007) 9. Y. Dumeige, S. Trebaol, L. Ghisa, T. K. N. Nguyen, H. Tavernier, and P. Feron, \"Determination of coupling regime of high Q resonators and optical gain of highly selective amplifiers,\" J. Opt. Soc. Am. B 25, 2073 2080 (2007) 10. A. C. Tamboli, E. D. Haberer, R. Sharma, K. H. Lee, S. Nakamura, and E. L. Hu, \"Room temperature continuous wave lasing in GaN/InGaN microdisks,\" Nat. photonics 1, 61 64 (2007) 11. M. L. Gorodetsky, A. A. Savchenkov, and V. S. Ilchenko, \"Ultimate Q of optical microsphere,\" Opt. Lett. 21, 453 455 (1996) 12. M. Sumetsky, \"Mode localization and the Q factor of a cylindrical microresonator,\" Opt. Lett. 35, 2385 2387 (2010) 13. M. Sumetsky, \"Whispering gallery bottle microcavities: the three dimensional etalon,\" Opt. Lett. 29, 8 10 (2004) 14. M. Sumetsky, \"Localization of light on a cone: theoretical evidence and experimental demonstration for an optical fiber,\" Opt. Lett. 29, 145 147 (2011) Vol. 25, No. 15 24 Jul 2017 OPTICS EXPRESS 17021 #294517 https:/doi.org/10.1364/OE.25.017021 Journal (c) 2017 Received 3 May 2017; revised 2 Jun 2017; accepted 3 Jun 2017; published 10 Jul 2017 15. A. A. Barannik, S. A. Bunyaev, and N. T. Cherpak, \"Conical quasioptical dielectric resonator,\" Tech. Phys. Lett. 31, 811 812 (2005) 16. A. A. Kishk, Y. Yin, and A. W. Glisson, \"Conical dielectric resonator antennas for wide band applications,\" IEEE Trans. Antennas Propag. 50, 469 474 (2002) 17. F. Vollmer and S. Arnold, \"Whispering gallery mode biosensing: label free detection down to single molecules,\" Nat. Methods 5, 591 596 (2008) 18. V. R. Dantham, S. Holler, V. Kolchenko, Z. Wan, and S. Arnold, \"Taking whispering gallery mode single virus detection and sizing to the limit,\" Appl. Phys. Lett. 101, 043704 (2012) 19. H. Cao and J. Wiersig, \"Dielectric microcavities: Model systems for wave chaos and non Hermitian physics,\" Rev. Mod. Phys. 87, 61 111 (2015) 20. C. Gmachl, F. Capasso, E. E. Narimanov, J. U. Nochel, A. Douglas Stone, J. Faist, D. L. Sivco, and A. Y. Cho, \"High power directional emission from microlasers with chaotic resonators,\" Science 280, 1556 1564 (1998) 21. W. Fang, H. Cao, V. A. Podolskiy, and E. E. Narimanov, \"Dynamical localization in microdisk lasers,\" Opt. Express 13, 5641 5652 (1998) 22. C. Claire, E. E. Narimanov, F. Capasso, J. N. Baillargeon, and A. Y. Cho, \"Kolmogorov Arnold Moser transition and laser action on scar modes in semiconductor diode lasers with deformed resonators,\" Opt. Lett. 27, 824 826 (2002) 23. A. Lagarkov, I. Budashov, V. Chistyayev, A. Ezhov, A. Fedyanin, A. Ivanov, I. Kurochkin, S. Kosolobov, A. Latyshev, D. Nasmimov, I. Ryzhikov, M. Shcherbakov, A. Vaskin, and A. K. Sarychev, \"SERS active dielectric metamaterials based on periodic nanostructured,\" Opt. Express 24, 7133 7150 (2016) 24. S. S. Vergeles, A. K. Sarychev, and G. Tartakovsky, \"All dielectric light concentrator to subwavelength volume,\" Phys. Rev. B 95, 085401 (2017) 25. B. Yan, A. Thubagere, W. R. Premasiri, L. D. Ziegler, L. D. Negro, B. M. Reinhard, \"Engineered SERS substrates with multiscale signal enhancement: nanoparticle cluster arrays,\" ACS Nano 3, 1190 1202 (2009) 26. F. Brouers, S. Blacher, A.N. Lagarkov, A.K. Sarychev, P. Gadenne, and V. M. Shalaev, \"Theory of Giant Raman Scattering from Semicontinuous Metal Films,\" Phys. Rev. B 55, 13234 13245 (1997) 27. A. K. Sarychev and V. M. Shalaev, Electrodynamics of Metamaterials, (World Scientific, 2007) 28. S.O.Boyarintsev andA.K. 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Sipe, \"Surface enhanced Raman scattering in the presence of multilayer dielectric structures,\" J. Opt. Soc. Am. B. 29, 1863 1874 (2012) 33. A. I. Kuznetsov, A. E. Miroshnichenko, Y. H. Fu, J. Zhang, and B. Luk'yanchuk, \"Magnetic light,\" Sci. Rep. 2, 492 497 (2012) 34. P. Albella, M. A. Poyli, M. K. Schmidt, S. A. Maier, F. Moreno, J. J. Saenz, J. Aizpurua, \"Low Loss Electric and Magnetic Field Enhanced Spectroscopy with Subwavelength Silicon Dimers,\" J. Phys. Chem. C 117, 13573 13584 (2013) 35. R. M. Bakker, D. Permyakov, Y. F. Yu, D. Markovich, R. Paniagua Dominguez, L. Gonzaga, A. Samusev, Y. Kivshar, B. Luk'yanchuk, and A. I. Kuznetsov, \"Magnetic and Electric Hotspots with Silicon Nanodimers,\" Nano Lett. 15, 2137 2142 (2015) 36. A. E. Krasnok, A. E. Miroshnichenko, P. A. Belov, and Y. S. Kivshar, \"All dielectric optical nanoantennas,\" Opt. Express 20, 20599 20604 (2012) 37. Y.Hong,M. 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Melik Gaykazyan, D. A. Smirnova, B. Hopkins, K. E. Chong, D. Y. Choi, M. R. Shcherbakov, A. E. Miroshnichenko, D. N. Neshev, A. A. Fedyanin, and Y. S. Kivshar, \"Multifold enhancement of third harmonic generation in dielectric nanoparticles driven by magnetic Fano resonances,\" Nano Lett. 16, 4857 4861 (2016) 44. S. J. Kim, P. Fan, J. H. Kang, and M. L. Brongersma, \"Creating semiconductor metafilms with designer absorption Vol. 25, No. 15 24 Jul 2017 OPTICS EXPRESS 17022", "author_names": [ "", "Shadak Alee K" ], "corpus_id": 54691522, "doc_id": "54691522", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Light localization and SERS in tip shaped silicon metasurface", "venue": "", "year": 2017 }, { "abstract": "We introduce a non parity time symmetric three layer structure, consisting of a gain medium layer sandwiched between two phase change medium layers for switching of the direction of reflectionless light propagation. We show that for this structure unidirectional reflectionlessness in the forward direction can be switched to unidirectional reflectionlessness in the backward direction at the optical communication wavelength by switching the phase change material Ge2Sb2Te5 (GST) from its amorphous to its crystalline phase. We also show that it is the existence of exceptional points for this structure with GST in both its amorphous and crystalline phases which leads to unidirectional reflectionless propagation in the forward direction for GST in its amorphous phase, and in the backward direction for GST in its crystalline phase. Our results could be potentially important for developing a new generation of compact active free space optical devices. (c) 2017 Optical Society of America OCIS codes: (260.0260) Physical optics; (350.4238) Nanophotonics and photonic crystals; (130.2790) Guided waves. References and links 1. M. Moiseyev, Non Hermitian Quantum Mechanics (Cambridge University, 2011) 2. W. D. 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Hira, T. Homma, T. Uchiyama, K. Kuwamura, Y. Kihara, and T. Saiki, \"All optical switching of localized surface plasmon resonance in single gold nanosandwich using GeSbTe film as an active medium,\" Appl. Phys. Lett. 106, 031105 (2015) 38. M. Wuttig and N. Yamada, \"Phase change materials for rewriteable data storage,\" Nat. Mater. 6, 824 832 (2007) 39. M. H. R. Lankhorst, B. W. Ketelaarsand, and R. A. M. Wolters, \"Low cost and nanoscale non volatile memory concept for future silicon chips,\" Nat. Mater. 4, 347 352 (2005) 40. F. F. Schlich, P. Zalden, A. M. Lindenberg, and R. Spolenak, \"Color switching with enhanced optical contrast in ultrathin phase change materials and semiconductors induced by femtosecond laser pulses,\" ACS Photonics 2, 178 182 (2015) 41. M. Rude, R. E. Simpson, R. Quidant, V. Pruneri, and J. Renger, \"Active control of surface plasmon waveguides with a phase change material,\" ACS Photonics 2, 669 674 (2015) 42. Q. Wang, E. T. F. Rogers, B. Gholipour, C. Wang, G.Yuan, J. Teng, N. I. Zheludev, \"Optically reconfigurable metasurfaces and photonic devices based on phase change materials,\" Nat. Photonics 10, 60 65 (2016) 43. P. Li, X. Yang, T. W. W. Mab, J. Hanss, M. Lewin, A. U. Michel, M. Wuttig, and T. Taubner, \"Reversible optical switching of highly confined phonon polaritons with an ultrathin phase change material,\" Nat. Mater. 15, 870 876 (2016) 44. V. K. Mkhitaryan, D. S. Ghosh, M. Rude, J. Canet Ferrer, R. A. Maniyara, K. K. Gopalan, and V. Pruneri, \"Tunable Vol. 25, No. 22 30 Oct 2017 OPTICS EXPRESS 27284", "author_names": [ "" ], "corpus_id": 31344436, "doc_id": "31344436", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Switching of the direction of reflectionless light propagation at exceptional points in non PT symmetric structures using phase change materials", "venue": "", "year": 2017 } ]

[ { "abstract": "Hybrid organic inorganic perovskites allow the synthesis of high quality, nanostructured semiconducting films via easily accessible solution based techniques. This has allowed tremendous development in optoelectronic applications, primarily solar cells and light emitting diodes. Allowed by the ease of access to nanostructure, chirality has recently been introduced in semiconducting perovskites, as a promising way to obtain advanced control of charge and spin and for developing circularly polarized light sources. Circular polarization of photo luminescence (CPL) is a powerful tool to probe the electronic structure of materials. However, CPL in chiral perovskites has been scarcely investigated, and a study in bulk thin films and at room temperature is still missing. In this work we fabricate bromine based chiral perovskites by using a bulky chiral organic cation mixed with CsBr, resulting in Ruddlesden Popper perovskite thin films. We measure CPL on these films at room temperature and, by using unpolarized photo excitation, we record a degree of circular polarization of photo luminescence in the order of 10 3 and provide a full spectral characterization of CPL. Our results show that chirality is imparted on the electronic structure of the semiconductor; we hypothesize that the excess in polarization of emitted light originates from the charge in the photo generated Wannier exciton describing an orbit in a symmetry broken environment. Furthermore, our experiments allow to directly measure the magnetic dipole moment of the optical transition, which we estimate to be 0.1 mB. Finally, we discuss the implications of our findings on the development of chiral semiconducting perovskites as sources of circularly polarized light.", "author_names": [ "Daniele Di Nuzzo", "Linsong Cui", "Jake L Greenfield", "Baodan Zhao", "Richard H Friend", "Stefan C J Meskers" ], "corpus_id": 218975051, "doc_id": "218975051", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Circularly Polarized Photo Luminescence from Chiral Perovskite Thin Films at Room Temperature.", "venue": "ACS nano", "year": 2020 }, { "abstract": "Monolayer two dimensional (2D) transition metal dichalcogenides (TMDs) have attracted great interest in spintronics and valleytronics due to the spin valley locking effect. To efficiently control and manipulate the valley pseudospin is of paramount importance for valley based electronics and optoelectronics. A variety of strategies have been developed to address the valley pseudospin including optical, electrical, and magnetic methods; nonetheless, they involve either below liquid nitrogen temperature or an external magnetic field, which increases the cost and complexity of the devices. Here, we report a straightforward way to manipulate valley polarization in monolayer TMDs via selective spin injection in chiral 2D perovskite/monolayer TMD (e.g. MoS2 and WSe2) van der Waals heterostructures without requiring an external magnetic field or specially designed device structures. We show the dangling bond free vdW interface can allow an impressive average spin injection efficiency of 78% to produce persistent valley polarization in monolayer MoS2 (WSe2) over 10% from liquid nitrogen temperature to above 200 K. We attribute the valley polarization of monolayer MoS2 (WSe2) to selective spin injection from chiral 2D perovskites, which can effectively introduce population imbalance between valleys in monolayer MoS2 (WSe2) Our findings provide an alternative strategy to manipulate the valley polarization in TMDs without requiring circularly polarized light excitation, below liquid nitrogen temperature, or external magnetic field, and thus would promote the development of perovskite based spintronic and valleytronic devices.", "author_names": [ "Yingying Chen", "Jiaqi Ma", "Zeyi Liu", "Junze Li", "Xiangfeng Duan", "Dehui Li" ], "corpus_id": 225100908, "doc_id": "225100908", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Manipulation of Valley Pseudospin by Selective Spin Injection in Chiral Two Dimensional Perovskite/Monolayer Transition Metal Dichalcogenide Heterostructures.", "venue": "ACS nano", "year": 2020 }, { "abstract": "Hybrid organic/inorganic lead halide perovskites (LHPs) have recently emerged as extremely promising photonic materials. However, the exploration of their optical nonlinearities has been mainly focused on the third and higher order nonlinear optical (NLO) effects. Strong second order NLO responses are hardly expected from ordinary LHPs due to their intrinsic centrosymmetric structures, but are highly desirable for advancing their applications in the next generation integrated photonic circuits. Here we demonstrate the fabrication of a novel noncentrosymmetric LHP material by introducing chiral amines as the organic component. The nanowires grown from this new LHP material crystallize in a noncentrosymmetric P1 space group and demonstrate highly efficient second harmonic generation (SHG) with high polarization ratios and chiroptical NLO effects. Such a chiral perovskite skeleton could provide a new platform for future engineering of optoelectronic functionalities of hybrid perovskite materials.", "author_names": [ "Chunqing Yuan", "Xinyue Li", "Sergey Semin", "Ya-qing Feng", "Th Rasing", "Jialiang Xu" ], "corpus_id": 51972568, "doc_id": "51972568", "n_citations": 57, "n_key_citations": 0, "score": 0, "title": "Chiral Lead Halide Perovskite Nanowires for Second Order Nonlinear Optics.", "venue": "Nano letters", "year": 2018 }, { "abstract": "The recent convergence of chiral molecules with metal halide perovskite frameworks gives rise to an interesting family of chiral systems: two dimensional, chiral hybrid organic inorganic perovskites (chiral HOIPs) While possessing photovoltaic properties of traditional HOIPs, this class of materials is endowed with chirality through its organic ligands in which the degeneracy of the electron spin in charge transport is broken, i.e. the Chirality Induced Spin Selectivity (CISS) effect manifests, making it a promising platform to bridge opto spintronic studies and the CISS effect. In this work chiral HOIP/NiFe heterostructures are studied by means of the magneto optical Kerr effect using a Sagnac interferometer. Upon illumination of the chiral HOIPs, the Kerr signal at the chiral HOIP NiFe interface changes and a linear dependence of the response on the magnetic field is observed. The sign of the slope was found to depend on the chirality of the HOIPs. The results demonstrate the utility of chiral HOIP materials for chiral opto spintronic applications.", "author_names": [ "Zhengjie Huang", "Brian P Bloom", "Xiaojuan Ni", "Zheni N Georgieva", "Melissa Marciesky", "Eric Vetter", "Feng Liu", "David H Waldeck", "Dali Sun" ], "corpus_id": 220629888, "doc_id": "220629888", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Magneto Optical Detection of Photoinduced Magnetism via Chirality Induced Spin Selectivity in 2D Chiral Hybrid Organic Inorganic Perovskites.", "venue": "ACS nano", "year": 2020 }, { "abstract": "Perovskite nanocrystals (PCNs) exhibited excellent absorption and luminescent optical properties. Inorganic silica nanohelices are used as chiral templates to induce optically active properties to CsPbBr3 PNCs grafted on their surfaces. In suspension, PNCs synthesized and grafted on the right (or left) handed silica helices do not show any detectable chiroptical properties. In contrast, in a dried film state, they show large circular dichroism (CD) and circularly polarized luminescence (CPL) signals with dissymmetric factor up to 6*10 3. Grazing incidence X ray scattering, tomography electron microscopy (EM) and cryo EM have shown closely and helically packed PNCs if the nanohelices@PNCs are dried in contrast to much more loosely organized PNCs solvated in suspension. Simulations based on the coupled dipole method (CDM) demonstrate that the CD comes from the dipolar interaction between PNC assembled into a chiral structure. We show that the CD decreases as the interparticle distance increases. These results indicate that closely packed and helically arranged PNCs on silica nanohelices result in an increase of the optically active properties in the film state.", "author_names": [ "Peizhao Liu", "Weidong Chen", "Yutaka Okazaki", "Yann Battie", "Lysiane Brocard", "Marion Decossas", "Emilie Pouget", "Peter Muller-Buschbaum", "Brice Kauffmann", "Shaheen H Pathan", "Takashi Sagawa", "Reiko Oda" ], "corpus_id": 221476812, "doc_id": "221476812", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "Optically Active Perovskite CsPbBr3 Nanocrystals Helically Arranged on Inorganic Silica Nanohelices.", "venue": "Nano letters", "year": 2020 }, { "abstract": "Colloidal metal halide perovskite nanocrystals (NCs) with chiral ligands are outstanding candidates as a circularly polarized luminescence (CPL) light source due to many advantages such as high photoluminescence quantum efficiency, large spin orbit coupling, and extensive tunability via composition and choice of organic ligands. However, achieving pronounced and controllable polarized light emission remains challenging. Here, we develop strategies to achieve high CPL responses from colloidal formamidinium lead bromide (FAPbBr3) NCs at room temperature using chiral surface ligands. First, we show that replacing a portion of typical ligands (oleylamine) with short chiral ligands (R) 2 octylamine) during FAPbBr3 NC synthesis results in small and monodisperse NCs which yield high CPL with average luminescence dissymmetry g factor, glum 6.8 x 10 2. To the best of our knowledge, this is the highest among reported perovskite materials at room temperature to date and represents around 10 fold improvement over the previously reported colloidal CsPbClxBryI3 x y NCs. In order to incorporate NCs into any optoelectronic or spintronic application, the NCs necessitate purification which removes a substantial amount of the chiral ligands and extinguishes the CPL signals. To circumvent this issue, we also developed a post synthetic ligand treatment using a different chiral ligand, (R /S )methylbenzylammonium bromide, which also induces a CPL with an average glum 1.18 x 10 2. This post synthetic method is also amenable for long range charge transport since methylbenzylammonium is quite compact in relation to other surface ligands. Our demonstrations of high CPL and glum from both as synthesized and purified perovskite NCs at room temperature suggest a route to demonstrate colloidal NC based spintronics.", "author_names": [ "Young-Hoon Kim", "Yaxin Zhai", "E Ashley Gaulding", "Severin N Habisreutinger", "Taylor Moot", "Bryan A Rosales", "Haipeng Lu", "Abhijit Hazarika", "Roman Brunecky", "Lance M Wheeler", "Joseph J Berry", "Matthew C Beard", "Joseph M Luther" ], "corpus_id": 220470247, "doc_id": "220470247", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Strategies to Achieve High Circularly Polarized Luminescence from Colloidal Organic Inorganic Hybrid Perovskite Nanocrystals.", "venue": "ACS nano", "year": 2020 }, { "abstract": "Micro and nanolasers are miniaturized light sources with great potential in optical imaging, sensing, and communication. While various micro and nanolasers have been synthesized, they are mostly linearly polarized and thus strongly restricted in many new applications, e.g. chiral resolution in synthetic chemistry, cancerous tissue imaging, information storage, and processing. Herein, we experimentally demonstrate the circularly polarized surface emitting perovskite lasers by integrating the as grown perovskite microcrystals with an all dielectric metalens. The perovskite microcrystal serves as an optical microcavity and produces linearly polarized laser emission, which is collected by a geometric phase based TiO2 metalens. The left handed circularly polarized components are collimated by the metalens into a directional laser beam with a divergent angle of <0.9deg, whereas the right handed components are strongly diverged by the same metalens. Consequently, the right handed circularly polarized components are filtered out, and perovskite lasers with high directionality and pure circular polarization have been experimentally realized.", "author_names": [ "Wei Dai", "Yujie Wang", "Ruixue Li", "Yubin Fan", "Geyang Qu", "Yunkai Wu", "Qinghai Song", "Jiecai Han", "Shumin Xiao" ], "corpus_id": 227157612, "doc_id": "227157612", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Achieving Circularly Polarized Surface Emitting Perovskite Microlasers with All Dielectric Metasurfaces.", "venue": "ACS nano", "year": 2020 }, { "abstract": "Low dimensional lead halide perovskite materials are an emerging class of solution processable semiconductors with promising potential applications in optoelectronic devices. Unfortunately, it is impossible to synthesize high crystalline quality low dimensional perovskite single crystals without using chemotoxicity solution such as dimethylformamide (DMF)/dimethyl sulfoxide (DMSO) or applying heating. Herein we report an economical and universal aqueous method to synthesize 2D layered and 1D chained perovskite single crystals at room temperature. The resultant chiral 2D perovskites can efficiently and selectively emit and detect circularly polarized light at room temperature. The as synthesized 1D perovskite single crystals exhibit strong quantum confinement and enhanced self trapped states that give efficient warm circularly polarized white light emission. This aqueous synthetic method is general for other high quality low dimensional lead halide perovskite single crystals and thus our findings would motivate more fundamental investigations on low dimensional perovskites for potential optoelectronic applications.", "author_names": [ "Jinye Wang", "Chen Fang", "Jiaqi Ma", "Shuaihao Wang", "Long Jin", "Wancai Li", "De-Hui Li" ], "corpus_id": 199389388, "doc_id": "199389388", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Aqueous Synthesis of Low Dimensional Lead Halide Perovskites for Room Temperature Circularly Polarized Light Emission and Detection.", "venue": "ACS nano", "year": 2019 }, { "abstract": "Hybrid organic inorganic perovskites (HOIPs) offer long carrier diffusion lengths, high absorption coefficients, tunable band gaps and long spin lifetimes. The flexible crystal structure and ionic nature of HOIPs make it possible to allow tuning of their material properties through rational design, including the incorporation of chiral organic ligands. Recently, chiral HOIPs have emerged as promising materials for chiroptoelectronics, spintronics and ferroelectrics. They exhibit high photoluminescence polarization (17% without an external magnetic field) good device performance (a circularly polarized photodetector had 100 times higher responsivity than one based on a chiral metasurface) and high saturated polarization ~2 times higher than that of barium titanate) Here, we review the latest advances in chiral HOIPs and investigate the specific benefits of combining chiral organic and inorganic components in perovskites. We discuss demonstrations of chiroptical and ferroelectric applications, and conclude with our perspective on the future opportunities for chiral HOIPs. Chiral hybrid organic inorganic perovskites combine the remarkable optical, electrical and spintronic properties of perovskites with chirality. This Review systematically introduces the latest advances in chiral perovskites, surveys their structure property relationships and details their chiroptical and ferroelectric applications.", "author_names": [ "Guankui Long", "Randy P Sabatini", "Makhsud I Saidaminov", "Girish Lakhwani", "Abdullah Rasmita", "Xiaogang Liu", "Edward H Sargent", "Wei-bo Gao" ], "corpus_id": 212642249, "doc_id": "212642249", "n_citations": 65, "n_key_citations": 0, "score": 0, "title": "Chiral perovskite optoelectronics", "venue": "Nature Reviews Materials", "year": 2020 }, { "abstract": "New fashioned bismuth silver oxide (BSO) perovskite nano catalysts have been synthesized by a simple and easy co deposition method, with silver nitrate and bismuth acid sodium as raw materials. Photocatalytic degradation characteristics of tetracycline under UV irradiation and structural transformation on BSO have been studied systematically. The degradation conditions were optimized by single factor experiment and orthogonal experiment. The results show that the highest degradation rate can reach 95.79% and the first order reaction rate coefficient k 0.0361 min 1 During the recycle photocatalytic process, the material structural transformation (BSO is gradually transformed into highly active Bi 2 O 2 CO 3 after multiple degradation) of the catalyst has been systematically studied.", "author_names": [ "Jianmin Zhou", "Meiqing Yu", "Jiayi Peng", "Ronghao Lin", "Zesheng Li", "Changling Yu" ], "corpus_id": 218531312, "doc_id": "218531312", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Photocatalytic degradation characteristics of tetracycline and structural transformation on bismuth silver oxide perovskite nano catalysts", "venue": "Applied Nanoscience", "year": 2020 } ]

[ { "abstract": "Processor specialization has become the development trend of modern processor industry. It is quite possible that this will still be the main stream in the next decades of semiconductor era. As the diversity of heterogeneous systems grows, organizing computation efficiently on systems with multiple kinds of heterogeneous processors is a challenging problem and will be a normality. In this paper, we analyze some state of the art task scheduling algorithms of heterogeneous computing systems and propose a Degree of Node First (DONF) algorithm for task scheduling of fine grained parallel programs on heterogeneous systems. The major innovations of DONF include: 1) simplifying task priority calculation for directed acyclic graph (DAG) based fine grained parallel programs which not only reduces the complexity of task selection but also enables the algorithm to solve the scheduling problem for dynamic DAGs; 2) building a novel communication model in the processor selection phase that makes the task scheduling much more efficient. They are achieved by exploring finegrained parallelism via a dataflow program execution model, and validated through experimental results with a selected set of benchmarks. The results on synthesized and real world application DAGs show a very good performance. The proposed DONF algorithm significantly outperforms all the evaluated state of the art heuristic algorithms in terms of scheduling length ratio (SLR) and efficiency.", "author_names": [ "Han Lin", "Mingfan Li", "Chengfan Jia", "Junnan Liu", "Hong An" ], "corpus_id": 203640147, "doc_id": "203640147", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Degree of Node Task Scheduling of Fine Grained Parallel Programs on Heterogeneous Systems", "venue": "Journal of Computer Science and Technology", "year": 2019 }, { "abstract": "The task based parallel programming model is widely used to parallelize dense linear algebra (DLA) [4] This model is utilized with tiled algorithms that divide DLA routines into small sub tasks with dependencies [2] This approach enables tasks to be executed asynchronously while preserving dependencies. Thus. it not only reduces synchronization points (a disadvantage of the fork join approach [4] but facilitates load balancing in a heterogeneous system. Fine grained partitioning by tiled algorithms achieves a high degree of parallelism, but it causes data communication overhead proportional in the number of tiles. This overhead is particularly noticeable with distributed systems, where nodes communicate via a network rather than shared memory. Therefore, a method to obtain a tile size that gives the best performance is required. In this paper, we reduce the data communication overhead by caching data inside nodes, and by finding the optimal tile size for partitioning data in the task based programming model.", "author_names": [ "Yonghyun Ryu" ], "corpus_id": 49563479, "doc_id": "49563479", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Node level optimization by caching data and choosing the optimal tile size for parallel dense linear algebra on distributed systems: student research abstract", "venue": "SAC", "year": 2018 }, { "abstract": "Exascale computers are expected to be made of millions of nodes and billions of threads of execution. To support high degrees of parallelism for various applications, the threads and task scheduling needs to be fine grained and should be able to execute in the order of tens to a few hundred CPU cycles. Overdecomposition of applications to fine grained applications is ideal to achieve maximum speed up and there is a need for a parallel runtime system which can launch tasks for execution and report the results with very low latency at high levels of concurrency. This work aims at enabling the launch of independent tasks on many core accelerator hardware architectures and mechanisms to support tasks of fine granularity on the order of tens of few hundreds of CPU cycles at a large scale. This work also focuses on analyzing the performance of various queue based data structures commonly used in parallel programming languages and runtime systems. This analysis is essential for designing an efficient runtime system for scheduling billions of tasks with very low latency and high throughput. Lastly, the runtime would also support data dependencies and task dependencies required for task based shared memory parallel programming.", "author_names": [ "Poornima Nookala", "DR Peter Dinda", "DR Kyle Hale" ], "corpus_id": 145819076, "doc_id": "145819076", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "XTASK eXTreme fine grAined concurrent taSK invocation runtime", "venue": "", "year": 2017 }, { "abstract": "We describe a programming abstraction for heterogeneous parallel hardware, designed to capture a wide range of popular parallel hardware, including GPUs, vector instruction sets and multicore CPUs. Our abstraction, which we call HPVM, is a hierarchical dataflow graph with shared memory and vector instructions. We use HPVM to define both a virtual instruction set (ISA) and also a compiler intermediate representation (IR) The virtual ISA aims to achieve both functional portability and performance portability across heterogeneous systems, while the compiler IR aims to enable effective code generation and optimization for such systems. HPVM effectively supports all forms of parallelism used to achieve computational speedups (as opposed to concurrency) including task parallelism, coarse grain data parallelism, fine grain data parallelism, and pipelined parallelism. HPVM also enables flexible scheduling and tiling: different nodes in the dataflow graph can be mapped flexibly to different combinations of compute units, and the graph hierarchy expresses memory tiling, essential for achieving high performance on GPU and CPU targets.", "author_names": [ "Prakalp Srivastava", "Maria Kotsifakou", "Vikram S Adve" ], "corpus_id": 15033820, "doc_id": "15033820", "n_citations": 6, "n_key_citations": 2, "score": 0, "title": "HPVM: A Portable Virtual Instruction Set for Heterogeneous Parallel Systems", "venue": "ArXiv", "year": 2016 }, { "abstract": "Modern GPUs are gradually used by more and more cluster computing systems as the high performance computing units due to their outstanding computational power, whereas bringing node level architectural heterogeneity to cluster. In this paper, based on MPI and CUDA programming model, we aim to investigate task scheduling for GPU heterogeneous cluster by taking into account the node level heterogeneous characteristics. At first, based on our GPU heterogeneous cluster, we classify executing tasks to six major classifications according to their parallelism degrees, input data sizes, and processing workloads. Then, aiming to realize optimal mapping between tasks and computing resources, a task scheduling strategy is presented. The strategy consists of two key algorithms. The first is packing task algorithm (PTA) used to pack multiple tasks into a single task, such packing provides us a way of task classification converting according to the characteristic of computing resources. The second is system level scheduling algorithm(SLSA) used to distribute parallel and sequential tasks to corresponding nodes, to maintain the load balance.", "author_names": [ "Keliang Zhang", "Baifeng Wu" ], "corpus_id": 15767217, "doc_id": "15767217", "n_citations": 7, "n_key_citations": 1, "score": 0, "title": "Task Scheduling for GPU Heterogeneous Cluster", "venue": "2012 IEEE International Conference on Cluster Computing Workshops", "year": 2012 }, { "abstract": "The goal of this paper is to implement an efficient matrix inversion of symmetric positive definite matrices on heterogeneous GPU based systems. The matrix inversion procedure can be split into three stages: computing the Cholesky factorization, inverting the Cholesky factor and calculating the product of the inverted Cholesky factor with its transpose to get the final inverted matrix. Using high performance data layout, which represents the matrix in the system memory with an optimized cache aware format, the computation of the three stages is decomposed into fine grained computational tasks. The data flow programming model can then be represented as a directed acyclic graph, where nodes represent tasks and edges the dependencies between them. Standard implementations of matrix inversions as well as other numerical algorithms (e.g. linear and eigenvalue solvers) available in the state of theart numerical libraries (e.g. LAPACK) rely on the expensive fork join paradigm to achieve parallel performance and are characterized by artifactual synchronization points, which have to be removed to fully exploit the underlying hardware capabilities. Our tile algorithmic approach allows to remove those bottlenecks and to flawlessly execute the tasks, as soon as the data dependencies are satisfied. A hybrid runtime environment system becomes paramount to dynamically schedule the numerical kernels on the available processing units, whether it is a hardware accelerator (i.e, GPU) or a homogeneous multicore (i.e. x86) and this is transparently carried out from the user. Preliminary results are shown on a dual socket quadcore Intel Xeon 2.67GHz workstation with two nVIDIA Fermi C2070 GPU cards. Our implementation (448 Gflop/s) results in up to 5 and 6 fold improvement compared to the equivalent routines from MAGMA V1.0 and PLASMA V2.4, respectively, and 10 fold improvement compared to LAPACK V3.2 linked with multithreaded Intel MKL BLAS V10.2, with a matrix size of 24960x 24960. Keywords Matrix Inversion; Tile Algorithms; Dynamic LoadBalanced Scheduling; Heterogeneous CPU GPU Computing", "author_names": [ "Huda Ibeid", "Dinesh K Kaushik", "David E Keyes", "Hatem Ltaief" ], "corpus_id": 17424691, "doc_id": "17424691", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Toward Accelerating the Matrix Inversion Computation of Symmetric Positive Definite Matrices on Heterogeneous GPU Based Systems", "venue": "", "year": 2011 }, { "abstract": "We present a runtime framework for the execution of work loads represented as parallel operator directed acyclic graphs (PO DAGs) on heterogeneous multi core platforms. PO DAGs combine coarse grained parallelism at the graph level with fine grained parallelism within each node, lending naturally to exploiting the intra and inter processing element parallelism present in heterogeneous platforms. We identify four important criteria Suitability, Locality, Availability and Criticality (SLAC) and show that all these criteria must be considered by a heterogeneous runtime framework in order to achieve good performance under varying application and platform characteristics. The proposed model driven runtime (MDR) considers all the aforementioned factors, and tradeoffs among them, by utilizing performance models. These performance models are used to drive key run time decisions such as mapping of tasks to PEs, scheduling of tasks on each PE, and copying data between memory spaces. We discuss the software architecture and implementation of MDR, and evaluate it using several benchmark programs on three different heterogeneous platforms that contain multi core CPUs and GPUs. The hardware platforms represent server, laptop, and netbook class systems. MDR achieves up to 4.2X speedup (1.5X on average) over the best of CPU only, GPU only, round robin, GPU first, and utilization driven schedulers. We also perform a sensitivity analysis that establishes the importance of considering all four SLAC criteria in order to achieve high performance execution in a heterogeneous runtime framework.", "author_names": [ "Jacques A Pienaar", "Anand Raghunathan", "Srimat T Chakradhar" ], "corpus_id": 16836813, "doc_id": "16836813", "n_citations": 27, "n_key_citations": 5, "score": 0, "title": "MDR: performance model driven runtime for heterogeneous parallel platforms", "venue": "ICS '11", "year": 2011 }, { "abstract": "Recent and future parallel clusters and supercomputers use symmetric multiprocessors SMPs and multi core processors as basic nodes, providing a huge amount of parallel resources. These systems often have hierarchically structured interconnection networks combining computing resources at different levels, starting with the interconnect within multi core processors up to the interconnection network combining nodes of the cluster or supercomputer. The challenge for the programmer is that these computing resources should be utilized efficiently by exploiting the available degree of parallelism of the application program and by structuring the application in a way which is sensitive to the heterogeneous interconnect.In this article, we pursue a parallel programming method using parallel tasks to structure parallel implementations. A parallel task can be executed by multiple processors or cores and, for each activation of a parallel task, the actual number of executing cores can be adapted to the specific execution situation. In particular, we propose a new combined scheduling and mapping technique for parallel tasks with dependencies that takes the hierarchical structure of modern multi core clusters into account. An experimental evaluation shows that the presented programming approach can lead to a significantly higher performance compared to standard data parallel implementations.", "author_names": [ "Jorg Dummler", "Thomas Rauber", "Gudula Runger" ], "corpus_id": 62561834, "doc_id": "62561834", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Combined scheduling and mapping for scalable computing with parallel tasks", "venue": "BIOKDD 2012", "year": 2012 }, { "abstract": "Recent and future parallel clusters and supercomputers use symmetric multiprocessors (SMPs) and multi core processors as basic nodes, providing a huge amount of parallel resources. These systems often have hierarchically structured interconnection networks combining computing resources at different levels, starting with the interconnect within multi core processors up to the interconnection network combining nodes of the cluster or supercomputer. The challenge for the programmer is that these computing resources should be utilized efficiently by exploiting the available degree of parallelism of the application program and by structuring the application in a way which is sensitive to the heterogeneous interconnect. In this article, we pursue a parallel programming method using parallel tasks to structure parallel implementations. A parallel task can be executed by multiple processors or cores and, for each activation of a parallel task, the actual number of executing cores can be adapted to the specific execution situation. In particular, we propose a new combined scheduling and mapping technique for parallel tasks with dependencies that takes the hierarchical structure of modern multi core clusters into account. An experimental evaluation shows that the presented programming approach can lead to a significantly higher performance compared to standard data parallel implementations.", "author_names": [ "Jorg Dummler", "Thomas Rauber", "Gudula Runger" ], "corpus_id": 19422819, "doc_id": "19422819", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Combined scheduling and mapping for scalable computing with parallel tasks", "venue": "Sci. Program.", "year": 2012 }, { "abstract": "Current software and hardware limitations prevent Many Task Computing (MTC) workloads from leveraging hardware accelerators boasting Many Core Computing architectures. This work aims to address the programmability gap between MTC and accelerators, through the innovative CUDA middleware GeMTC. By working at the warp level, GeMTC enables heterogeneous task scheduling and 10x number of workers compared to CUDA. In order to span multiple accelerators across nodes, we have adopted the Swift parallel programming system, which can both support fine grained millisecond tasks and extreme scale supercomputers at 100K cores. Keywords Many Task Computing, Swift, GPGPU, CUDA", "author_names": [ "Scott J Krieder", "Benjamin Grimmer", "Dustin Shahidehpour", "Jeffrey Johnson", "Justin M Wozniak", "Michael Wilde", "Ioan Raicu" ], "corpus_id": 16640632, "doc_id": "16640632", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Towards Efficient Many Task Computing on Accelerators in High End Computing Systems", "venue": "", "year": 2013 } ]

[ { "abstract": "Although many attempts have been made to design a fault current limiting circuit breaker (FCLCB) for medium voltage electric power systems, no economically attractive solution has been achieved so far. A novel concept for an F CLCB is introduced based on a hybrid arrangement of semiconductors, temperature dependent resistors, and a newly developed fast opening mechanical switch. The latter utilizes one part of an electrodynamic repulsion drive, which is concurrent with the moving double contact system. Laboratory tests as well as computer simulations of the complete FCLCB verify as an example the feasibility for the goal ratings 12 kV and 2/20 kA (single phase) A cost analysis shows the FCLCB to be more expensive than a conventional generator circuit breaker but to be in the price range of the Is limiter and below the costs of superconducting FCL principles. It is concluded that the method provides the basis for further commercial product development.", "author_names": [ "Mischa Steurer", "K Frolich", "Walter Holaus", "Kurt Kaltenegger" ], "corpus_id": 18660609, "doc_id": "18660609", "n_citations": 93, "n_key_citations": 7, "score": 1, "title": "A Novel Hybrid Current Limiting Circuit Breaker for Medium Voltage: Principle and Test Results", "venue": "IEEE Power Engineering Review", "year": 2002 }, { "abstract": "The high fault current of dc line is a major threat to multiterminal voltage source converter based HVDC (VSC HVDC) system. However, dc circuit breaker (DCCB) with large capacity and fast breaking speed is still under development. Therefore, fault current limitation is vital for the multiterminal VSC HV DC system. This paper proposes a simple and easily applied hybrid current limiting circuit (HCLC) at dc side, which consists of a current limiting inductor (CLI) and an energy dissipation circuit (EDC) in parallel with the CLI. The CLI is designed to reduce the requirement for the DCCB's capacity and breaking speed. The EDC, which consists of thyristor controlled resistors, is proposed to reduce the stress on energy absorption element (metal oxide arrester) in DCCB and to accelerate the fault current interruption. The design and discussion about the HCLC parameters are performed in detail. By employing the proposed HCLC, dc line fault in the multiterminal system can be isolated effectively with existing DCCB technology, and fast system restoration without power interruption of healthy part can be achieved. Numerous simulations with real time digital simulator and comparisons with traditional schemes have demonstrated the promising performance of the proposed HCLC. The effectiveness of the HCLC's topology has also been verified by a simplified and scaled test circuit.", "author_names": [ "Jian Wei Liu", "Nengling Tai", "Chunju Fan", "Shi Chen" ], "corpus_id": 23139232, "doc_id": "23139232", "n_citations": 60, "n_key_citations": 5, "score": 0, "title": "A Hybrid Current Limiting Circuit for DC Line Fault in Multiterminal VSC HVDC System", "venue": "IEEE Transactions on Industrial Electronics", "year": 2017 }, { "abstract": "Summary form only given. Although many attempts have been made to design a fault current limiting (FCL) circuit breaker (FCLCB) for medium voltage electric power systems, no economically attractive solution has been achieved so far. In this paper, a novel concept for a FCLCB is introduced based on a hybrid arrangement of semiconductors, temperature dependent resistors, and a newly developed fast opening mechanical switch. The latter utilizes one part of an electrodynamic repulsion drive, which is concurrent with the moving double contact system. Laboratory tests as well as computer simulations of the complete FCLCB verify as an example the feasibility of the goal ratings 12 kV and 2/20 kA (single phase) A cost analysis shows the FCLCB to be more expensive than a conventional generator circuit breaker, but to be in the price range of the Is limiter and below the cost of the superconducting FCL principles. It is concluded that the presented method provides the basis for further commercial product development.", "author_names": [ "Mischa Steurer", "K J Frohlich", "Walter Holaus", "Kurt Kaltenegger" ], "corpus_id": 110401764, "doc_id": "110401764", "n_citations": 68, "n_key_citations": 4, "score": 0, "title": "A novel hybrid current limiting circuit breaker for medium voltage: principle and test results", "venue": "2003 IEEE Power Engineering Society General Meeting (IEEE Cat. No.03CH37491)", "year": 2003 }, { "abstract": "This paper studies the problem of heat transfer in a thermistor, which is used as a switching device in electronic circuits. The temperature field is coupled to the current flow by ohmic heating in the device, and the problem is rendered highly nonlinear by a very rapid variation of electrical conductivity with temperature. Approximate methods based on high activation energy asymptotics are developed to describe the transient heat flow, which occurs when the circuit is switched on. In particular, it is found that a transient \"surge\" phenomenon (akin to thermal runaway, but self saturating) occurs, and we conjecture that this phenomenon may be associated with cracking of thermistors, which sometimes occurs during operation.", "author_names": [ "Andrew C Fowler", "Ian A Frigaard", "Sam Howison" ], "corpus_id": 17897050, "doc_id": "17897050", "n_citations": 65, "n_key_citations": 3, "score": 0, "title": "Temperature surges in current limiting circuit devices", "venue": "", "year": 1992 }, { "abstract": "Arc motion in low voltage (240 VAC) high current (10/sup 3/ 10/sup 4/A. current limiting circuit breakers is dominated by arc root mobility. The mobility is influenced by the gas flow and gas composition in the contact region, but there is little experimental data on these effects. New pressure and spectral data measurement during arc movement are presented using a flexible test apparatus and an arc imaging system. These measurements are used to investigate gas flow characteristics in the arc chamber. The chemical and physical phenomena occurring during the arc motion are discussed. The combination of optical and spectral data provides new insight into the arc motion. The influences of arc chamber material, contact material, and contact opening speed, are investigated to improve arc control for a low contact opening velocity.", "author_names": [ "John W McBride", "K Pechrach", "Paul M Weaver" ], "corpus_id": 16399584, "doc_id": "16399584", "n_citations": 58, "n_key_citations": 4, "score": 0, "title": "Arc motion and gas flow in current limiting circuit breakers operating with a low contact switching velocity", "venue": "", "year": 2002 }, { "abstract": "In Japan, a new network distribution system with advanced protective and operational functions designed to meet the needs of today's information society is being studied. For this new distribution system, the authors have developed high speed current limiting equipment using gate turn off thyristors (GTOs) to lower the breaking capacity of switches and to suppress instantaneous voltage drops. The main components of this equipment are a high speed vacuum switch and a GTO switch connected in parallel. The usual load current is carried by the vacuum switch. In the case of a system fault, the fault current is commutated to and interrupted by the GTO switch by opening the vacuum switch. The time from fault occurrence to current interruption is less than 1 ms. This response time is about 100 times as fast as that of mechanical breakers. This equipment dose not require a large cooling system and is compact compared with conventional solid state equipment.", "author_names": [ "Takamu Genji", "Osamu Nakamura", "Masaru Isozaki", "Makoto Yamada", "Tadashi Morita", "Masanobu Kaneda" ], "corpus_id": 110966939, "doc_id": "110966939", "n_citations": 80, "n_key_citations": 2, "score": 0, "title": "400 V class high speed current limiting circuit breaker for electric power system", "venue": "", "year": 1994 }, { "abstract": "This paper presents a review of different topologies of power converters that are suitable for interfacing power sources to the dc distribution bus of a microgrid. Despite the high controllability of electronic power converters, not all converter topologies behave the same during a bus fault condition. Some topologies are able to limit fault currents, can participate in the protection scheme and can decrease the risk of catastrophic damage. Other topologies lose controllability in a situation of fault on the distribution bus and need to be protected against permanent damage by fast fuses, circuit breaker and fault current limiters. Power converters, such as back to back VSCs, buck type isolated converters, Full Bridge MMCs and similar, can be controlled to limit the fault currents, coordinated with protection devices, minimize the risk of catastrophic damage of the distribution system and increase the resilience and survivability of the microgrid.", "author_names": [ "Pietro Cairoli", "Rostan Rodrigues", "Huaxi Zheng" ], "corpus_id": 44222515, "doc_id": "44222515", "n_citations": 28, "n_key_citations": 2, "score": 0, "title": "Fault current limiting power converters for protection of DC microgrids", "venue": "SoutheastCon 2017", "year": 2017 }, { "abstract": "The saturated core superconducting fault current limiter (SCSFCL) is an important new device for limiting fault current in power grids. As the loss of its core and tank can reach up to a few hundred kilowatts and influence both the transitional process and the steady limiting state, the method for simulating its current limiting effect considering the loss needs to be tackled. In this paper, a field circuit coupled simulation method for computing the current limiting effect of the SCSFCL is presented. The SCSFCL is simulated in detail by the finite element model, which can reflect both its magnetic and loss properties. The SCSFCL is excited by a voltage source in series with inner impedance, which is the simplified circuit of the power grid. The approach of getting this simplified power grid is given. Moreover, approaches of achieving high simulation accuracy and efficiency are also given. One is the varying simulation time step approach based on the characteristics of the voltage waveform. The other is setting a proper beginning phase of the voltage source to decrease the transitional period and increase the simulation efficiency. Finally, the structure of an SCSFCL in a 220 kV power grid is given, and its current limiting effects under a 50 kA fault current in the cases of withdrawing and keeping the dc bias are compared, showing that the former case is of a little bit higher current limiting effect.", "author_names": [ "Yuelong Jia", "Jiansheng Yuan", "Zhengjun Shi", "Haojun Zhu", "Yiqing Geng", "Jun Zou" ], "corpus_id": 27208549, "doc_id": "27208549", "n_citations": 17, "n_key_citations": 2, "score": 0, "title": "Simulation Method for Current Limiting Effect of Saturated Core Superconducting Fault Current Limiter", "venue": "IEEE Transactions on Applied Superconductivity", "year": 2016 }, { "abstract": "DC fault current limitation is important for the low voltage dc distribution network, because the existing dc selective protection cannot act fast enough. However, the typical dc fault current limiting method installing dc reactors directly in the dc system will lead to negative influence on the system normal operation and dc circuit breaker (DCCB) fast isolation. This paper proposed a novel solid state circuit breaker (SSCB) with self adapt fault current limiting capability, namely, no negative influence on the dc distribution network normal operation, swift fault current limiting response to the dc fault, and efficient cooperation between the fault current limitation and isolation. The hybrid configuration strategy of the proposed SSCB and mechanical DCCB for multiterminal dc distribution network is proposed to reduce the conducting power loss and investment from the scale of the whole system. Finally, the experiment tests and simulation cases are carried out to verify the working principle and superiorities of the proposed SSCB.", "author_names": [ "Bin Li", "Jiawei He", "Ye Li", "Ruisheng Li" ], "corpus_id": 77393079, "doc_id": "77393079", "n_citations": 40, "n_key_citations": 1, "score": 0, "title": "A Novel Solid State Circuit Breaker With Self Adapt Fault Current Limiting Capability for LVDC Distribution Network", "venue": "IEEE Transactions on Power Electronics", "year": 2019 }, { "abstract": "In order to maintain the reliability of the opening operation of a new vacuum DC current limiting circuit breaker in cutting off short circuit current,the vacuum dielectric recovery after current zero was investigated.An equivalent experiment was designed and set up.Dynamic vacuum dielectric recovery characteristic of the circuit breaker during opening of the vacuum contacts was achieved from experiments results and theoretical deduction.Researching results show that the breakdown voltage of the vacuum interrupter can be improved with less arcing energy and higher contact moving speed;and with the increasing of arcing time the breakdown voltage reduces at first and increases later.These results can be used in the designing of the new vacuum DC circuit breaker.", "author_names": [ "" ], "corpus_id": 114807529, "doc_id": "114807529", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Vacuum Dielectric Recovery Characteristics of a Novel Current Limiting Circuit Breaker Base on Artificial Current Zero", "venue": "", "year": 2012 } ]

[ { "abstract": "Thanks to the efforts of various research groups over the past decade in the area of tunable microwave passive components, the idea of tunability has become very well established within the RF/microwave community [1] [5] Many different designs have shown that tunable microwave components can improve the performance of a radio system in many ways. The tunability of microwave components has been realized using semiconductor devices (such as varactors or p i n diodes) and microelectromechanical systems (MEMS) devices. While these offer many advantages, such as high quality factor and high bandwidth operation (mainly for MEMS devices) and fast switching speeds (mainly for varactors and p i n diodes) they come with two major drawbacks.", "author_names": [ "Kamran Entesari", "Alireza Pourghorban Saghati" ], "corpus_id": 41917121, "doc_id": "41917121", "n_citations": 55, "n_key_citations": 3, "score": 1, "title": "Fluidics in Microwave Components", "venue": "IEEE Microwave Magazine", "year": 2016 }, { "abstract": "These days it seems that every research institution has a program to develop MEMS components; sensors, switches, optics, or fluidics. Some of these components are already finding their way into the marketplace, and MEMS/microelectronic systems on a chip are already being designed. HRL Laboratories, LLC, as been building RF MEMS switches for the last three years. [1,2] The design and fabrication of metal metal contact cantilever switches on GaAs substrates, and the measured performance of the switches will be presented, including switching speed, insertion loss, and isolation. Some examples of how these switches can be integrated into simple filters and antenna elements will be exhibited to show the potential for MEMS applications in electronic systems Microwave and millimeter wave phased array antennas typically operate over a narrow bandwidth, but for many applications multiple frequency operation would be highly desirable. This would require either a tunable antenna element with a multiband feed network or a multiband antenna array and the tunable feed network. PIN diodes and ferrites have been used for decades as tuning devices for antennas [3,4] Recently, optoelectronically tunable antennas have been reported [5 7] where photoconductive switches are used to connect dipole segments for frequency tuning or beam scanning. With the advent of MEMS processing, new RF switch structures are possible, and have the advantages over the other tuning techniques in simplicity, ultralow insertion loss, high isolation, power efficiency, and compactness. Two canonical RF MEMS switch structures are being actively developed, the capacitive switch and the contacting switch. The capacitive switch uses a metal membrane that is physically in contact with the ground electrode of a planar transmission line. A DC voltage causes opposite charges to be induced between the membrane and the ground electrode, which in turn results in an attractive force which pulls the membrane toward the oppositely charged electrode. A thin dielectric insulator (on the order of a few microns) prevents the switch from shorting. The effective RF capacitance of this switch increases from the switch \"off\" state to the switch \"on: state, with an on off capacitance ratio up to the order of 100 [8] Reliable contacts are essential for the metal contact RF MEMS switch, which depends on the making and breaking of an actual metal to metal joint, a feat complicated by the low forces available from microactuation. In the force regime of tens to hundreds of micronewtons, surface states, adsorbed contaminants, and nanometerdepth material properties dominate the properties of metallic contact, and limited information has been available to the MEMS switch designer. Recent studies into this phenomenon by [9] have determined useful design criteria for pure gold contacts electroplated from sodium sulfite solution. Based on this work and other recent low force contact studies [10,11] switch designs were developed to provide 200 uN of contact force per contact and maximal heat sinking to the substrate. During the past three years, HRL Laboratories has developed a metal contact RF MEMS switch for operation up through 40 GHz, and beyond. The design and fabrication of the switches will be presented in this paper. In addition, the performance of this switch, including some limited lifetime data and power handling capability, will be provided. Finally, examples of the integration of these switches into frequency tuned filters and antennas will demonstrate the potential application of these switches to subsystem components. 2. CANTILEVER RF MEMS SWITCH CONFIGURATION AND PERFORMANCE The RF MEMS switch, shown in figure 1, has a suspended cantilever trilayer structure of metal sandwiched between insulating layers to improve the thermal stability of the devices and reduce the effect of as fabricated stress mismatch between the layers. A microphotograph of the switch is shown in figure 2. The cantilever beam includes the top actuation electrode and the RF switch. The actuation electrodes are isolated from the RF transmission line, thus no bias circuit is required for this switch. In addition, the switch actuation, being electrostatic, does not draw any DC current (there is a very small transient capacitance charging current) thus the required power for applications where arrays of switches are needed can remain reasonable.", "author_names": [ "Robert Y Loo", "Gregory L Tangonan", "Daniel F Sievenpiper", "James H Schaffner", "T Y Hsu", "Hui-Pin Hsu" ], "corpus_id": 113119847, "doc_id": "113119847", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Reconfigurable Antenna Elements Using RF MEMS Switches", "venue": "", "year": 2000 }, { "abstract": "Abstract Background Microwave assisted extraction (MAE) have gained enormous popularity as a preferred method for the recovery of various active compounds from food materials. They proffer benefits such as the reduction of extraction time, environmental friendliness, low cost and enable automation or on line coupling to other analytical procedures. Recently, newer add ons or technological modifications have been incorporated into MAE systems, in an effort to continuously improve extraction efficiency and ensure a greener implementation. Scope and approach The core pathways of such meliorations include integrating microwave extraction with other technologies, e.g. ultrasound assisted extraction (UAE) negative pressure cavitation (NPC) enzyme assisted extraction (EAE) hydrodiffusion extraction (HDE) and supercritical fluid extraction (SFE) or replacement of extraction medium with suitable alternatives including ionic liquids, deep eutectic solvents, non ionic surfactants, etc. This review confers their underlying principles and mechanisms, equipment and apparatuses, practicalities, as well as resultant benefits such as increased yield, intensification of mass transfer and reduction of energy consumption, in a manner not achievable by MAE alone or previous intermediary modifications. Key findings and conclusions It is hoped that this paper reinforces the need to initiate more studies focused on process validation and optimization of such emerging MAE systems, in furtherance of their scale up, sustainability and robust adoption by the food industry.", "author_names": [ "Flora-Glad Chizoba Ekezie", "Da-Wen Sun", "Jun-Hu Cheng" ], "corpus_id": 114265297, "doc_id": "114265297", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "Acceleration of microwave assisted extraction processes of food components by integrating technologies and applying emerging solvents: A review of latest developments", "venue": "", "year": 2017 }, { "abstract": "Abstract Microwave assisted pyrolysis (MWAP) provides distinctive heating for the conversion of coal into liquid fuels. This work investigated the effects of MWAP on the microstructure of bituminous coals by using Fourier transform infrared spectroscopy (FTIR) mercury intrusion porosimetry (MIP) and Scanning Electron Microscope (SEM) techniques. FTIR results showed that MWAP can lead to the decomposition of oxygen functional groups and aliphatic hydrocarbons. Removal of these hydrophilic groups significantly weakens the hydrophilicity of coal. With continuous exposure to microwaves, unstable components such as alcohol, phenol and carboxylic acid are converted into ether groups. Cyclization and aromatization induced by microwave heating improve the maturation of coal. MIP and SEM results indicated that the jet force exerted by the high pressure steam and gaseous products under MWAP gives a great boost to the opening, enlargement and connection of pores. Furthermore, the thermal stresses induced by microwave selective heating enlarge the fractures and create new cracks, providing seepage space for fluids. MWAP of bituminous coals can not only release moisture and volatiles but also create seepage space by modifying the pore and fracture structure.", "author_names": [ "He Fei Li", "Shiliang Shi", "Bai-quan Lin", "Jiexin Lu", "Qing Ye", "Yonghua Lu", "Zheng Wang", "Yi-du Hong", "Xiangnan Zhu" ], "corpus_id": 202098411, "doc_id": "202098411", "n_citations": 68, "n_key_citations": 0, "score": 0, "title": "Effects of microwave assisted pyrolysis on the microstructure of bituminous coals", "venue": "Energy", "year": 2019 }, { "abstract": "Tamarind (Tamarindus indica) belongs to the family Leguminosae. It is commonly growing in tropical and subtropical regions now and is one of the most important plant resources as cuisine materials. Antioxidative activity of tamarind seeds was investigated. An ethanol extract prepared from the seed coat contained antioxidative activity as measured by the thiocyanate and thiobarbituric acid (TBA) method. Essential oils are highly odorous droplets found in minimal quantities in the flowers, stems, leaves, roots and barks of aromatic plants. They are not recognized as true oils as the vegetable oils, but highly fluid and volatile. Experts recognize an essential oil by its aroma and test the oil characteristics such as vaporization and crystallization point using Differential Scanning Calorimetry (DSC) DSC has emerged as a powerful experimental technique for determining thermodynamic properties of biomacromolecules [1] Volatile components of tamarind leaves and seed locally grown will be isolated by Microwave Assisted Extraction (MAE) The presence of essential oil as the volatile components will be investigated to determine whether this method is effective or not to extract the oil from tamarind leaves and seed. The parameters that will be measured are the time for the oil droplets formation and the optimum temperature for the extraction of oil. At the end of the extraction, amber color oil was obtained. Results showed that the time for the oil droplets formation increasing with the increasing weight of sample for both tamarind leaves and seed samples. The optimum temperature for the extraction obtained was 125 oC with the yield of 1.2 mL of seed oil. The vaporization and crystallization point of oil are presented in the DSC curve and the specific heat capacity of the oil are calculated.", "author_names": [ "M A Zawawi", "Ahmed H A Dabwa", "Lili Shakira Hassan" ], "corpus_id": 226961287, "doc_id": "226961287", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "EXTRACTION OF ESSENTIAL OILS FROM TAMARIND LEAVES AND SEED USING MICROWAVE EXTRACTION", "venue": "", "year": 2020 }, { "abstract": "Characterization of selenium nanoparticles and selenium nanoparticle human serum albumin conjugates prepared in nanopowder form, their elemental composition, and particle size distribution were investigated with a microwave plasma optical emission spectrometry operating in a single particle mode. This new analytical technique was used for the first time to examine the molecular interaction between selenium nanoparticles and human serum albumin regarding potential biomedical applications of selenium nanoparticles. Nanopowder sample was introduced to a helium plasma by pneumatic nebulization based on fluidized bed approach and measured with a time resolution of 20 ms. Both selenium nanoparticles and selenium nanoparticle human serum albumin conjugates were characterized by observation of synchronous signals from different particle components. Plots of the time correlation between Se and C signals for all particles in selenium nanoparticles and selenium nanoparticle human serum albumin conjugates samples differed from each other in degree of correlation and synchronicity of recorded signals. The interaction between selenium nanoparticles and human serum albumin was confirmed using Bradford assay. For selenium nanoparticles synthesized using yeast cells, the percentage of bound protein was only of 4% whereas for selenium nanoparticles synthesized using yeast extract as a stabilizing agent it was 16%", "author_names": [ "Magdalena Borowska", "Ewelina Pawlik", "Krzysztof Jankowski" ], "corpus_id": 220732725, "doc_id": "220732725", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Investigation of interaction between biogenic selenium nanoparticles and human serum albumin using microwave plasma optical emission spectrometry operating in a single particle mode", "venue": "Monatshefte fur Chemie Chemical Monthly", "year": 2020 }, { "abstract": "Surface phenomenon such as cavitation erosion corrosion limits the working life and durability of the fluid machines through significantly altering the efficiency. Surface modification is an apparent and economical route for improving the sustainability of these components. Recently developed complex concentrated alloys (CCAs) or high entropy alloys (HEAs) possess exceptional properties owing to high configurational entropy. We developed CCA coatings on the stainless steel using a facial and effective microwave processing technique. The effect of Al molar fraction in AlxCoCrFeNi (x 0.1 3) CCAs on ultrasonic cavitation erosion corrosion was investigated in 3.5% NaCl solution. For comparison, cavitation erosion and electrochemical corrosion behavior of the pre and post tested samples was also performed. Detailed microstructure and mechanical characterization of the developed coatings were also preformed using different analytical techniques. The equimolar CCA coating showed apical degradation resistance under both pure erosion and erosion corrosion conditions. The observed behavior is attributed to high strain hardening, optimal hardness, fracture toughness, and utmost stability of the passive layer. The phenomenal conjugation of these properties was associated with highest configurational entropy for equimolar composition resulting in sluggish diffusion, and severe lattice straining. Compared to pits, striations and cracks characterizing the morphology of the degraded stainless steel, the equimolar and Al0.1CoCrFeNi CCAs showed TTS (tearing topograph surface) as the dominant failure mode characterized by presence of microplastic deformation. The degradation of the Al3CoCrFeNi CCA occurred mainly through brittle failure mode. The difference in failure mechanism is related to the mechanical properties and underlying microstructure.", "author_names": [ "Rakesh B Nair", "Harpreet Singh Arora", "Harpreet Singh Grewal" ], "corpus_id": 52280351, "doc_id": "52280351", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Microwave synthesized complex concentrated alloy coatings: Plausible solution to cavitation induced erosion corrosion.", "venue": "Ultrasonics sonochemistry", "year": 2019 }, { "abstract": "This article presents a frequency reconfigurable RF impedance tuner using eight cascaded fluidic cells to cover the frequency band [0.9, 2.4] GHz. The tuner is made of eight fluidic fillable cavities on top of a coplanar waveguide transmission line in a single low temperature cofired ceramic (LTCC) substrate. Each cavity is either kept empty or filled with deionized (DI) water to alter the substrate's permittivity and so change the tuner's response. Closed form expressions are derived and used to dimension the tuner's individual cells, while 3 D field simulations are used to complete the design of a single cell and an entire eight cell tuner. Both components are fabricated, and good agreement between simulation and measured is observed. The fabricated tuner is used to build a fluidic reconfigurable RF amplifier.", "author_names": [ "Dorra Bahloul", "Ammar B Kouki" ], "corpus_id": 225709762, "doc_id": "225709762", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "LTCC Based Fluidic Tuners for Low Microwave Frequency Reconfigurable Circuits", "venue": "IEEE Transactions on Microwave Theory and Techniques", "year": 2020 }, { "abstract": "The tumor detection performance of two air based metallic microwave breast imaging systems is evaluated experimentally using breast phantoms having realistic tissue permittivities. The first system has a circular cylindrical shape, whereas the second has a faceted hemispherical shape. No immersion medium is utilized making these systems low loss quasi resonant structures. The breast phantoms are composed of three distinct volumes representing structurally simplified adipose, fibroglandular, and tumor regions filled with tissue mimicking fluids. Scattered field data are collected, at multiple frequencies, on the inside surface of the chambers: the normal component of the electric field at 18 locations in the cylindrical chamber and 24 tangential magnetic field components in the faceted chamber. Quantitative 3 D imaging of these high contrast phantoms is performed utilizing the finite element contrast source inversion algorithm wherein an inhomogeneous numerical background, constituting prior information, is introduced. Experiments are conducted with various accuracies of this prior information, both in terms of the permittivity that is used as well as the accuracy of the geometry compared with the true regions within the phantom. Image segmentation techniques based on thresholding the 3 D reconstructed images are evaluated for tumor detection. Utilizing receiver operating characteristic (ROC) curves, it is shown that taking the intersection of multifrequency thresholded 3 D images performs the best for detecting tumors.", "author_names": [ "Mohammad Asefi", "Anastasia Baran", "Joe Lovetri" ], "corpus_id": 201846947, "doc_id": "201846947", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "An Experimental Phantom Study for Air Based Quasi Resonant Microwave Breast Imaging", "venue": "IEEE Transactions on Microwave Theory and Techniques", "year": 2019 }, { "abstract": "This paper compares two types of microfluidic sensors that are designed for operation in ISM (Industrial, Scientific, Medical) bands at microwave frequencies of 2.45 GHz and 5.8 GHz. In the case of the first sensor, the principle of operation is based on the resonance phenomenon in a microwave circuit filled with a test sample. The second sensor is based on the interferometric principle and makes use of the superposition of two coherent microwave signals, where only one goes through a test sample. Both sensors are monolithic structures fabricated using low temperature co fired ceramics (LTCCs) The LTCC based microwave microfluidic sensor properties are examined and compared by measuring their responses for various concentrations of two types of test fluids: one is a mixture of water/ethanol, and the other is dopamine dissolved in a buffer solution. The experiments show a linear response for the LTCC based microwave microfluidic sensors as a function of the concentration of the components in both test fluids.", "author_names": [ "Karol Malecha", "Laura Jasinska", "Anna Grytsko", "Kamila Drzozga", "Piotr M Slobodzian", "Joanna Cabaj" ], "corpus_id": 67857139, "doc_id": "67857139", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Monolithic Microwave Microfluidic Sensors Made with Low Temperature Co Fired Ceramic (LTCC) Technology", "venue": "Sensors", "year": 2019 } ]

[ { "abstract": "A valuable reference for the most vital microelectronic components in the marketplace DRAMs are the technology drivers of high volume semiconductor fabrication processes for new generation products that, in addition to computer markets, are finding increased usage in automotive, aviation, military and space, telecommunications, and wireless industries. A new generation of high density and high performance memory architectures evolving for mass storage devices, including embedded memories and nonvolatile flash memories, are serving a diverse range of applications. Comprehensive and up to date, Advanced Semiconductor Memories: Architectures, Designs, and Applications offers professionals in the semiconductor and related industries an in depth review of advanced semiconductor memories technology developments. It provides details on: Static Random Access Memory technologies including advanced architectures, low voltage SRAMs, fast SRAMs, SOI SRAMs, and specialty SRAMs (multiport, FIFOs, CAMs) High Performance Dynamic Random Access Memory DDRs, synchronous DRAM/SGRAM features and architectures, EDRAM, CDRAM, Gigabit DRAM scaling issues and architectures, multilevel storage DRAMs, and SOI DRAMs Applications specific DRAM architectures and designs VRAMs, DDR SGRAMs, RDRAMs, SLDRAMs, 3 D RAM Advanced Nonvolatile Memory designs and technologies, including floating gate cell theory, EEPROM/flash memory cell design, and multilevel flash FRAMs and reliability issues Embedded memory designs and applications, including cache, merged processor, DRAM architectures, memory cards, and multimedia applications Future memory directions with megabytes to terabytes storage capacities using RTDs, single electron memories, etc. A continuation of the topics introduced in Semiconductor Memories: Technology, Testing, and Reliability, the author's earlier work, Advanced Semiconductor Memories: Architectures, Designs, and Applications offers a much needed reference to the major developments and future directions of advanced semiconductor memory technology.", "author_names": [ "Ashok K Sharma" ], "corpus_id": 108134661, "doc_id": "108134661", "n_citations": 56, "n_key_citations": 4, "score": 1, "title": "Advanced Semiconductor Memories: Architectures, Designs, and Applications", "venue": "", "year": 2009 }, { "abstract": "Memory modeling functional testing: reduced functional RAM chip model functional RAM chip testing functional ROM chip testing functional memory array testing functional memory board testing electrical testing: parametric testing dynamic testing on chip testing conclusions: address line scrambling various proofs software package.", "author_names": [ "Ad Van De Goor" ], "corpus_id": 62644180, "doc_id": "62644180", "n_citations": 870, "n_key_citations": 128, "score": 0, "title": "Testing Semiconductor Memories: Theory and Practice", "venue": "", "year": 1998 }, { "abstract": "Three dimensional integration enables stacking memory directly on top of a microprocessor, thereby significantly reducing wire delay between the two. Previous studies have examined the performance benefits of such an approach, but all of these works only consider commodity 2D DRAM organizations. In this work, we explore more aggressive 3D DRAM organizations that make better use of the additional die to die bandwidth provided by 3D stacking, as well as the additional transistor count. Our simulation results show that with a few simple changes to the 3D DRAM organization, we can achieve a 1.75x speedup over previously proposed 3D DRAM approaches on our memory intensive multi programmed workloads on a quad core processor. The significant increase in memory system performance makes the L2 miss handling architecture (MHA) a new bottleneck, which we address by combining a novel data structure called the Vector Bloom Filter with dynamic MSHR capacity tuning. Our scalable L2 MHA yields an additional 17.8% performance improvement over our 3D stacked memory architecture.", "author_names": [ "Gabriel H Loh" ], "corpus_id": 207168618, "doc_id": "207168618", "n_citations": 643, "n_key_citations": 54, "score": 0, "title": "3D Stacked Memory Architectures for Multi core Processors", "venue": "2008 International Symposium on Computer Architecture", "year": 2008 }, { "abstract": "The once ephemeral radiation induced soft error has become a key threat to advanced commercial electronic components and systems. Left unchallenged, soft errors have the potential for inducing the highest failure rate of all other reliability mechanisms combined. This article briefly reviews the types of failure modes for soft errors, the three dominant radiation mechanisms responsible for creating soft errors in terrestrial applications, and how these soft errors are generated by the collection of radiation induced charge. The soft error sensitivity as a function of technology scaling for various memory and logic components is then presented with a consideration of which applications are most likely to require soft error mitigation.", "author_names": [ "Robert C Baumann" ], "corpus_id": 16899139, "doc_id": "16899139", "n_citations": 1286, "n_key_citations": 90, "score": 0, "title": "Radiation induced soft errors in advanced semiconductor technologies", "venue": "IEEE Transactions on Device and Materials Reliability", "year": 2005 }, { "abstract": "This paper presents a state of the art review of error correcting codes for computer semiconductor memory applications. The construction of four classes of error correcting codes appropriate for semiconductor memory designs is described, and for each class of codes the number of check bits required for commonly used data lengths is provided. The implementation aspects of error correction and error detection are also discussed, and certain algorithms useful in extending the error correcting capability for the correction of soft errors such as a particle induced errors are examined in some detail.", "author_names": [ "Chin-Long Chen", "Mu Yue Hsiao" ], "corpus_id": 1111072, "doc_id": "1111072", "n_citations": 544, "n_key_citations": 41, "score": 0, "title": "Error Correcting Codes for Semiconductor Memory Applications: A State of the Art Review", "venue": "IBM J. Res. Dev.", "year": 1984 }, { "abstract": "We survey recent developments in the design of large capacity content addressable memory (CAM) A CAM is a memory that implements the lookup table function in a single clock cycle using dedicated comparison circuitry. CAMs are especially popular in network routers for packet forwarding and packet classification, but they are also beneficial in a variety of other applications that require high speed table lookup. The main CAM design challenge is to reduce power consumption associated with the large amount of parallel active circuitry, without sacrificing speed or memory density. In this paper, we review CAM design techniques at the circuit level and at the architectural level. At the circuit level, we review low power matchline sensing techniques and searchline driving approaches. At the architectural level we review three methods for reducing power consumption.", "author_names": [ "Kostas Pagiamtzis", "Ali Sheikholeslami" ], "corpus_id": 11178331, "doc_id": "11178331", "n_citations": 999, "n_key_citations": 92, "score": 0, "title": "Content addressable memory (CAM) circuits and architectures: a tutorial and survey", "venue": "IEEE Journal of Solid State Circuits", "year": 2006 }, { "abstract": "Signal integrity has become the key issue in most high performance digital designs. Now, from the foremost experts in the field, this book leverages theory and techniques from non related fields such as applied physics, communications, and microwave engineering and applies them to the field of high speed digital design. This approach creates an optimal combination of theory and practice that is meaningful to practicing engineers and graduate students alike.", "author_names": [ "Stephen H Hall", "Howard Heck" ], "corpus_id": 56523069, "doc_id": "56523069", "n_citations": 395, "n_key_citations": 52, "score": 0, "title": "Advanced Signal Integrity for High Speed Digital Designs", "venue": "", "year": 2009 }, { "abstract": "Keywords: thermodynamique lois fondamentales exergie reversibilite reaction chimique energie energie solaire cycles refrigeration Reference Record created on 2005 11 18, modified on 2016 08 08", "author_names": [ "Adrian Bejan" ], "corpus_id": 137048741, "doc_id": "137048741", "n_citations": 2333, "n_key_citations": 106, "score": 0, "title": "Advanced Engineering Thermodynamics", "venue": "", "year": 1988 }, { "abstract": "Preface. Introduction. PART I: SEMICONDUCTOR PHYSICS. Energy Bands and Carrier Concentration in Thermal Equilibrium. Carrier Transport Phenomena. PART II: SEMICONDUCTOR DEVICES. p n Junction. Bipolar Transistor and Related Devices. MOSFET and Related Devices. MESFET and Related Devices. Microwave Diodes, Quantum Effect, and Hot Electron Devices. Photonic Devices. PART III: SEMICONDUCTOR TECHNOLOGY. Crystal Growth and Epitaxy. Film Formation. Lithography and Etching. Impurity Doping. Integrated Devices. Appendix A: List of Symbols. Appendix B: International Systems of Units (SI Units) Appendix C: Unit Prefixes. Appendix D: Greek Alphabet. Appendix E: Physical Constants. Appendix F: Properties of Important Element and Binary Compound Semiconductors at 300 K. Appendix G: Properties of Si and GaAs at 300 K. Appendix H: Derivation of the Density of States in Semiconductor. Appendix I: Derivation of Recombination Rate for Indirect Recombination. Appendix J: Calculation of the Transmission Coefficient for a Symmetric Resonant Tunneling Diode. Appendix K: Basic Kinetic Theory of Gases. Appendix L: Answers to Selected Problems. Index.", "author_names": [ "S M Sze" ], "corpus_id": 93226361, "doc_id": "93226361", "n_citations": 3382, "n_key_citations": 222, "score": 0, "title": "Semiconductor Devices: Physics and Technology", "venue": "", "year": 1985 }, { "abstract": "Year 2009 marks the completion of 50 years of the invention of CORDIC (coordinate rotation digital computer) by Jack E. Volder. The beauty of CORDIC lies in the fact that by simple shift add operations, it can perform several computing tasks such as the calculation of trigonometric, hyperbolic and logarithmic functions, real and complex multiplications, division, square root, solution of linear systems, eigenvalue estimation, singular value decomposition, QR factorization and many others. As a consequence, CORDIC has been utilized for applications in diverse areas such as signal and image processing, communication systems, robotics and 3 D graphics apart from general scientific and technical computation. In this article, we present a brief overview of the key developments in the CORDIC algorithms and architectures along with their potential and upcoming applications.", "author_names": [ "Pramod Kumar Meher", "Javier Valls-Coquillat", "Tso-Bing Juang", "Krishnamurthy Sridharan", "Koushik Maharatna" ], "corpus_id": 5465045, "doc_id": "5465045", "n_citations": 488, "n_key_citations": 32, "score": 0, "title": "50 Years of CORDIC: Algorithms, Architectures, and Applications", "venue": "IEEE Transactions on Circuits and Systems I: Regular Papers", "year": 2009 } ]

[ { "abstract": "Nowadays, more attention has been placed on cost reductions and yield enhancement in the semiconductor industry. During the manufacturing process, a considerable amount of sensor data called status variables identification (SVID) is collected by sensors embedded in advanced machines. This data is a valuable source for data driven automatic fault detection and diagnosis at an early manufacturing stage to maintain competitive advantages. However, wafer processing times vary slightly from wafer to wafer, resulting in variable length signal data. The conventional approaches use much condensed data called fault detection and classification (FDC) data made by manually designed feature extraction. Or, recent deep learning approaches assume that all wafers have the same processing time, which is impotent to the variable length SVID. To detect and diagnose faults directly from the variable length SVID, we propose a self attentive convolutional neural network. In experiments using real world data from a semiconductor manufacturer, the proposed model outperformed other deep learning models with less training time and showed robustness at different sequence lengths. Compared to FDC data, SVID data showed better fault detection performance. Without manually investigating the lengthy sensor signals, abnormal sensor value patterns were found at the time specified by the model.", "author_names": [ "Eunji Kim", "Sungzoon Cho", "Byeongeon Lee", "Myoungsu Cho" ], "corpus_id": 181710095, "doc_id": "181710095", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Fault Detection and Diagnosis Using Self Attentive Convolutional Neural Networks for Variable Length Sensor Data in Semiconductor Manufacturing", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2019 }, { "abstract": "Many studies using sensor signals have been conducted in the field of fault detection and classification (FDC) for semiconductor manufacturing processes. This is because sensor signals generated in the semiconductor production process provide important information for predicting quality and yield of the finished product. However, as the process becomes more sophisticated and refined, normal and abnormal data with similar shape appears. They only show delicate differences and it is difficult to classify them using general classification algorithms. The purpose of this research is to present a preprocessing methodology for improving classification performance. The methodology consists of four steps based on signal segmentation and clustering methods. The experimental results illustrate the better performance of the proposed procedure.", "author_names": [ "Kyuchang Chang", "Jun-Geol Baek" ], "corpus_id": 208883567, "doc_id": "208883567", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Univiariate Signal Preprocessing Methodology for Fault Detection in Semiconductor Manufacturing Process", "venue": "2019 IEEE International Conference on Computational Science and Engineering (CSE) and IEEE International Conference on Embedded and Ubiquitous Computing (EUC)", "year": 2019 }, { "abstract": "Run to Run (R2R) control has become a common process regulating approach in the semiconductor industry. Conventionally, key process parameters are regulated with respect to the measured metrology data. However, wafer quality can be affected by complex factors related to equipment condition. The steady progress of information technologies enable us to collect and handle larger amounts of data, open new perspectives to explore the interactions between FDC (Fault Detection and Classification) data and product quality, i.e. wafer metrology, which should be considered simultaneously for developing improved R2R controllers. In this paper, the equipment condition is explicitly modeled and integrated into the core of a R2R controller, in order to accommodate this critical aspect of the system in deriving the control law, in order to reduce process variability in more effective way. Therefore, a new R2R control framework is proposed, which is called: Controller with Real time Equipment Condition (CREC) The effectiveness of the new control strategy is demonstrated and validated using the case study of a Chemical Mechanical Polishing (CMP) process, in collaboration with our industrial partner.", "author_names": [ "Wei-Ting Yang", "Jakey Blue", "Agnes Roussy", "Marco S Reis", "Jacques Pinaton" ], "corpus_id": 46957410, "doc_id": "46957410", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Advanced run to run controller in semiconductor manufacturing with real time equipment condition: APC: Advanced process control; AM: Advanced metrology", "venue": "2018 29th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2018 }, { "abstract": "Many studies on the prediction of manufacturing results using sensor signals have been conducted in the field of fault detection and classification (FDC) for semiconductor manufacturing processes. However, fault diagnosis used to find clues as to root causes remains a challenging area. In particular, process monitoring using neural networks has been employed to only a limited extent because it is a black box model, making the relationships between input data and output results difficult to interpret in actual manufacturing settings, despite its high classification performance. In this paper, we propose a convolutional neural network (CNN) model, named FDC CNN, in which a receptive field tailored to multivariate sensor signals slides along the time axis, to extract fault features. This approach enables the association of the output of the first convolutional layer with the structural meaning of the raw data, making it possible to locate the variable and time information that represents process faults. In an experiment on a chemical vapor deposition process, the proposed method outperformed other deep learning models.", "author_names": [ "Ki Bum Lee", "Sejune Cheon", "Chang Ouk Kim" ], "corpus_id": 22772949, "doc_id": "22772949", "n_citations": 160, "n_key_citations": 1, "score": 0, "title": "A Convolutional Neural Network for Fault Classification and Diagnosis in Semiconductor Manufacturing Processes", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2017 }, { "abstract": "Fault detection and classification (FDC) is important for semiconductor manufacturing to monitor equipment's condition and examine the potential cause of the fault. Each equipment in the semiconductor manufacturing process is often accompanied by a large amount of sensor readings, also called status variable identification (SVID) Identifying the key SVIDs accurately can make it easier for engineers to monitor the process and maintain the stability of the process and wafer productive yields. This article proposes using the random forests algorithm to analyze the importance of SVIDs of equipment sensors, automatically filters the key SVID by using <inline formula> <tex math notation=\"LaTeX\"{k} /tex math>/inline formula> means, and integrates various machine learning methods to verify the key SVIDs and identify key processing time and steps. Upon the key parameters are identified, the key processing time and steps are investigated subsequently. The ensemble models constructed on <inline formula> <tex math notation=\"LaTeX\"{k} /tex math>/inline formula> nearest neighbors <inline formula> <tex math notation=\"LaTeX\"{k} /tex math>/inline formula>NNs) and naive Bayes classifiers are presented for classifying wafers as normal or abnormal. Data visualization of multidimensional key SVIDs is performed by using <inline formula> <tex math notation=\"LaTeX\"{t} /tex math>/inline formula> distributed stochastic neighbor embedding <inline formula> <tex math notation=\"LaTeX\"{t} /tex math>/inline formula> SNE) to create a graphical aid in FDC for the process engineer. An empirical study is conducted to validate the proposed data driven framework for fault detection and diagnostic. The experimental results demonstrate that the proposed framework can detect abnormality effectively with highly imbalanced classes and also gain insightful information about the key SVIDs and corresponding key processing time and steps. <italic>Note to Practitioners</italic> The challenges of equipment sensor data analytics in semiconductor manufacturing include building the classifier to detect wafer abnormality correctly, identification of key status variable identifications (SVIDs) and processing time and steps of abnormality, and data visualization of the abnormality in a high dimensional feature space. This article proposes a data driven framework for fault detection and classification (FDC) during the wafer fabrication process by incorporating several useful machine learning approaches. Experimental results demonstrate that the proposed data driven framework can supply quality fault detection performances and provide valuable information regarding the critical SVIDs and associated key processing time for fault diagnostic. The engineers can utilize the extracted fault patterns to perform a prognosis of the aging effect on process tools or modules for health management.", "author_names": [ "Shu-Kai S Fan", "Chia-Yu Hsu", "Du-ming Tsai", "Fei He", "Chun-Chung Cheng" ], "corpus_id": 218776407, "doc_id": "218776407", "n_citations": 13, "n_key_citations": 0, "score": 1, "title": "Data Driven Approach for Fault Detection and Diagnostic in Semiconductor Manufacturing", "venue": "IEEE Transactions on Automation Science and Engineering", "year": 2020 }, { "abstract": "Nowadays, there are more attentions on cost control and yield enhancement in the semiconductor industry. Many manufacturers have the ability to collect the physical data called Status Variables Identification (SVID) by sensors embedded in the advanced machines during the manufacturing process. To maintain the competitive advantages, process monitoring and quick response to yield problem are pivotal in detecting the cause of the faults with the help of the sensor data. To state the physical nature of certain SVID, we usually transform SVID into Fault Detection and Classification parameters (FDC parameters) using statistical indicators. The data containing FDC parameters is called FDC data. This study aims to develop a multivariate analysis model to find out the crucial factors which may lead to process excursion among a large amount of FDC data. We proposed a 2 phase multivariate analysis framework: (1) the Least Absolute Shrinkage and Selection Operator (LASSO) is applied for key operation screening. (2) And Random Forest (RF) is used to rank the FDC parameters based on the key operations. Based on the results, domain engineers can quickly take actions responding to low yield problems.", "author_names": [ "Ying-Jen Chen", "Bo-Cheng Wang", "Jei-Zheng Wu", "Yi-Chia Wu", "Chen-Fu Chien" ], "corpus_id": 10614490, "doc_id": "10614490", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Big data analytic for multivariate fault detection and classification in semiconductor manufacturing", "venue": "2017 13th IEEE Conference on Automation Science and Engineering (CASE)", "year": 2017 }, { "abstract": "With the evolutions in sensing technologies and the increasing use of advanced process control techniques, terabytes of data are recorded today from manufacturing equipment during the process of semiconductor devices. These large amounts of data are then operated by FDC systems to assess the overall condition of the equipment. In this paper, we consider the Exponential Hybrid wise Multiway Principal Components Analysis (E HMPCA) a PCA derived model that include an Exponentially Weighted Moving Average component, for the condition monitoring of a Chemical Vapor Deposition tool in STMicroelectronics Rousset 8\" fab. In order to work directly on temporal signal from equipment sensors, the application of Dynamic Time Warping for data synchronization is also presented. A real occurred failure case is used to highlight the benefits of this approach on detection efficiency improvement and monitoring complexity reduction.", "author_names": [ "Alexis Thieullen", "Mustapha Ouladsine", "Jacques Pinaton" ], "corpus_id": 36824701, "doc_id": "36824701", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Application of PCA for efficient multivariate FDC of semiconductor manufacturing equipment", "venue": "ASMC 2013 SEMI Advanced Semiconductor Manufacturing Conference", "year": 2013 }, { "abstract": "As the high tech production system gets more complex, Equipment Condition Diagnosis (ECD) in semiconductor manufacturing for Fault Detection and Classification (FDC) is becoming more and more challenging than ever. This paper uses well known machine learning techniques such as Support Vector Machine (SVM) K Means clustering and Self Organizing Map (SOM) to develop an efficient ECD model. The process normality is checked by SVM following by decomposing the process dynamics via K Means. The abnormal observations are then projected into normal models built by Principal Component Analysis (PCA) Finally, by calculating the contribution values of out of control observations, different fault fingerprints with corresponding fault root are extracted again by K Means. The impact of clustering techniques is investigated by comparing K Means, SOM, and hierarchical clustering. An empirical study was conducted in collaboration with the leading semiconductor company in France to validate the methodology. The result shows that the proposed approach can effectively detect abnormal observations as well as automatically classify the fault fingerprints to give evident guidelines in explaining the detected faults.", "author_names": [ "Hamideh Rostami", "Jakey Blue", "Claude Yugma" ], "corpus_id": 6545935, "doc_id": "6545935", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Equipment Condition Diagnosis and Fault Fingerprint Extraction in Semiconductor Manufacturing", "venue": "2016 15th IEEE International Conference on Machine Learning and Applications (ICMLA)", "year": 2016 }, { "abstract": "Tool behavior modeling and diagnosis is a big challenge in modern semiconductor fabrication, in particular, with high product mix and complicated technology nodes. Tool condition monitoring has been long conducted by implementing the Fault Detection and Classification (FDC) system and analyzing the large amount of real time sensor data collected during the process. The tool condition hierarchy developed in the previous work proposed that the excursions can be firstly detected by an overall condition indicator and then intuitively traced down to the level of sensor groups. In this paper, a Run to Run (R2R) variation monitoring technique is developed in order to correlate the tool excursions with individual sensors, instead of sensor groups, and thus to close the diagnostic gap in the hierarchy. Therefore, the tool condition can be efficiently monitored by one overall indicator and the detected tool faults can be systematically diagnosed at the sensor level.", "author_names": [ "Jakey Blue", "Agnes Roussy", "Jacques Pinaton" ], "corpus_id": 12222645, "doc_id": "12222645", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Run to Run sensor variation monitoring for process fault diagnosis in semiconductor manufacturing", "venue": "2016 Winter Simulation Conference (WSC)", "year": 2016 }, { "abstract": "In the field of semiconductor manufacturing, people usually focus on the data of well designed databases, such as values from tool sensors, inline metrology data, or WAT data. These data are well structured and easily handled by engineers for further analysis. For example, integration engineers can compared CD metrology data to WAT data to catch out the root cause of abnormal device current, or equipment engineers can check FDC data to judge PM success or not.", "author_names": [ "Yan-Hsiu Liu", "Ji Fu Kung", "James Lin", "Y B Hsu" ], "corpus_id": 31913926, "doc_id": "31913926", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Using text mining to handle unstructured data in semiconductor manufacturing Yan Hsiu Liu", "venue": "2015 Joint e Manufacturing and Design Collaboration Symposium (eMDC) 2015 International Symposium on Semiconductor Manufacturing (ISSM)", "year": 2015 } ]

[ { "abstract": "Many semiconductor industries use Automated Test Equipment (ATE) which comprises of linear and mixed signals instruments. External Signal generators are usually not associated to the equipment's calibration or checker routine. This research introduces a method of testing the functionality of the signal generators by establishing a signal generator checker for automated test equipment using Analog to Digital Converter (ADC) evaluation board and Field Programmable Gate Array (FPGA) capture board. This setup will enable the system to focus on fundamental frequency and amplitude level of the signal generator. A Visual Basic Application (VBA) program was created to control the desired frequency and amplitude level of the signal generator. The FPGA evaluates the digital signal and graphically presents it in a system data platform software. In result, the graphical output displays the quality of the signal generator through the full scale fundamental frequency and amplitude levels. The common problems encountered using ATEs, namely; loosed RF cable, incorrect RF cable connections on ATE configuration, and noisy signal generators can be detected. This research is precedent to a more intelligent and complex signal generator checker to ensure signal integrity.", "author_names": [ "Limuel R Landicho", "Irvin B Garcia", "Glenn N Ortiz", "Mark Joseph B Enojas" ], "corpus_id": 216652488, "doc_id": "216652488", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Measuring Signal Generator Response Through An Adc Evaluation Board", "venue": "", "year": 2020 }, { "abstract": "Instruction in the theory and operation of analog electronic circuits remains an essential element of contemporary electrical engineering curricula. While computer based simulation of these circuits is extremely helpful to mastery of essential topics, hardware implementation of these circuits in the undergraduate electronics laboratory best reinforces theoretical explanations and solidifies understanding. However, hardware reinforcement of more advanced topics such as component dependent frequency response, feedback and pole compensation is more difficult to achieve. Hardware circuits implemented by students will inevitably possess anomalies and errors which thwart the achievement of a laboratory's teaching objectives. After some years of development, we have found that a prepared custom differential amplifier presented on small custom printed circuit board (PCB) can greatly improve the undergraduate laboratory experience with advanced analog amplifier circuits. This circuit performs in a predictable, repeatable manner since correct component connections and biasing has been established and parasitic circuit elements are fixed. Components within the circuit remain accessible to test equipment so students may verify circuit condition. External components chosen by the student can be easily added to illustrate important behaviors. Furthermore, additional stages can be added to this circuit, presenting additional opportunities for student design. We fabricate these circuits in sufficient numbers that inevitable student mis application of these PCBs is easily remedied. This paper discusses the objectives of instruction, theory of operation, implementation details, robustness and student experience related to this circuit. Sufficient detail is provided so that interested faculty may easily reproduce our design. Introduction Instruction in the theory and operation of analog electronic circuits remains an essential element of contemporary electrical engineering curricula. While computer based simulation of these circuits is extremely helpful to mastery of essential topics, hardware implementation of these circuits in the undergraduate electronics laboratory best reinforces theoretical explanations and solidifies understanding. However, hardware reinforcement of more advanced topics such as component dependent frequency response, feedback and pole compensation is more difficult to achieve. Hardware circuits P ge 1.32.1 Proceedings of the 2005 American Society for Engineering Education Annual Conference and Exposition Copyright (c) 2005, American Society for Engineering Education implemented by students will inevitably possess anomalies and errors which thwart the achievement of a laboratory's teaching objectives. After some years of development, we have found that a prepared custom differential amplifier presented on small custom printed circuit board (PCB) can greatly improve the undergraduate laboratory experience with advanced analog amplifier circuit concepts. In this paper, I present the pedagogical framework in which this amplifier is presented, details of the amplifier's design and operation, as well as information relevant to its fabrication and implementation. Pedagogical Framework The laboratory exercise which employs our printed circuit board (PCB) based amplifier is one of eight executed in our two semester required course sequence in electronics. Laboratory exercises are integrated with lecture and classroom exercises with the same faculty member responsible for both forms of instruction. Laboratory exercises throughout our curriculum follow a cycle of theoretical analysis or design followed by computer based simulation which are subsequently compared with hardware circuit performance. The first course in the electronics sequence, Electronics I El Engr 321 covers semiconductor physics and the theory of operation of the junction diode, bipolar junction transistor (BJT) and metal oxide semiconductor field effect transistor (MOSFET) Circuits involving small numbers of these active devices are used to illustrate their operation and practical importance. Complementary hardware laboratory exercises reinforce the concepts of diode and transistor biasing as well as small and large signal operation. The second electronics course, Electronics II El Engr 322 focuses upon multi transistor circuits including differential amplifiers, feedback, stability, high current output stages and a variety of small and medium scale complementary MOSFET digital circuits. Our PCB based amplifier is an integral part of the second laboratory exercise of this second course. The block of instruction supported by EE 322 Lab 2 presumes a theoretical understanding of direct coupled differential and single bipolar junction transistor amplifiers. It also presumes an understanding of the origin of circuit poles and the methods for estimating and simulating their effects. The block of instruction which Lab 2 supports begins with a formal study of analog feedback. Feedback circuit topologies, feedback circuit implementation, criteria for stability, stability analysis and methods for stability augmentation are presented. We also choose to include output stage operation and limitations in this block of instruction. The theory of operation of push pull output stages includes signal swing limitations, methods for biasing, power dissipation considerations and frequency response. The Laboratory Exercise Within the pedagogical framework described above, we wished to create a laboratory exercise which would simultaneously illustrate both feedback and output stage concepts. The associated amplifier needed a differential input making it possible to reinforce the feedback concepts illustrated through operational amplifiers. The open loop gain of the amplifier needed to be low enough to be directly measured without saturation. P ge 1.32.2 Proceedings of the 2005 American Society for Engineering Education Annual Conference and Exposition Copyright (c) 2005, American Society for Engineering Education To illustrate the impact of pole compensation under feedback, the amplifier had to be designed inherently unstable at feedback factors near unity. Furthermore, the amplifier needed a common collector output stage through which output signal swing limitations under low resistance loads could be illustrated. The dc bias voltage of the output node needed to be adjustable across a range of about one volt above and below ground potential. The latter characteristic permits students some freedom of design in their output stage. In addition to the electronic characteristics, the amplifier had to support an exercise subject to additional practical limitations. The exercise had to complement out design, simulate, build and measure instructional cycle. This meant it our amplifier had to be simple enough to be simulated through our department standard circuit analysis software, OrCAD Cadence PSPICE. The exercise was further constrained to work within the limitation of our student laboratory equipment. Administrative constraints further limit the number of days which could be devoted to this exercise to seven 100 minute class meetings, spread over approximately three weeks, plus approximately six out of class clock hours. This is because the USAF Academy's curriculum is designed so that the average student can complete assigned work in 42 lesson meeting of a total of 150 minutes each. Finally, any hardware we developed had to be reasonably robust and be designed from readily available components. It also had to be fabricated in such a way that the inevitable student mis use could be corrected with reasonable ease. From the perspective of laboratory equipment, we have available an HP Model 54645A 100 MHz sampling oscilloscope, Kepco MPS620M 15V@1A DC power supplies and a Wavetek Datron 50MHz Model 80 function generator. Standard value leaded discrete components are available and may be interconnected through prototyping boards. One obvious alternative to the custom circuit approach we have taken in the subject exercise was the application of a commercial operational amplifier whose dominant pole frequency could be adjusted externally. The pole adjustment feature is essential to illustration of pole shifting and stability under feedback. Our experience has shown that such an approach has two distinct disadvantages. First, commercial operational amplifiers have very high gain bandwidth products. It would therefore very difficult to experimentally evaluate the loop gain of these amplifiers at low frequency. Second, commercial operational amplifiers offer students no opportunity to adjust internal parameters or to measure the condition of internal circuit nodes. The ability to verify circuit bias conditions and small signal gain across the amplifier is too important to ignore. Another approach we considered in the development of this exercise was simply to require students construct a common pre designed differential amplifier from discrete components. Our experience has shown this approach would inevitably involve student wiring errors which would slow the lab's execution and divert attention from the exercises objectives. Furthermore, the magnitude of parasitic capacitances inherent to proto boards and exact placement of components, would vary widely among student P ge 1.32.3 Proceedings of the 2005 American Society for Engineering Education Annual Conference and Exposition Copyright (c) 2005, American Society for Engineering Education designs. These variations would make it unlikely that every student would see the desired frequency dependent behavior or achieve success in pole compensation. The Amplifier Based upon the considerations described above, we concluded the best method for executing the proposed laboratory exercise was to build our own custom amplifier presented to students on a custom PCB. In order to keep the circuit simple and reasonably small, and to fu", "author_names": [ "Kenneth J Soda" ], "corpus_id": 55266806, "doc_id": "55266806", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Custom Printed Circuit Board Differential Amplifier For Instruction In Undergraduate Analog Electronics", "venue": "", "year": null }, { "abstract": "The Superconducting RF Test Facility (STF) at the High Energy Accelerator Research Organization (KEK) was built for research and development of the International Linear Collider (ILC) Several digital low level radio frequency (LLRF) control systems were developed at the STF. The purposes of these developments are to construct a minimal configuration of the ILC LLRF system and achieve the amplitude and phase stability of the accelerating field in the superconducting accelerator. Evaluations of digital LLRF control systems were conducted during the conditioning of eight superconducting cavities performed between October and November 2016. The digital LLRF control system configured for ILC was demonstrated and the performance fulfilled the required stability criteria of the accelerating field in the ILC. These evaluations are reported in this paper. INTRODUCTION A field programmable gate array (FPGA) based digital low level radio frequency (LLRF) control system will be employed in the International Linear Collider (ILC) to achieve the radio frequency (RF) stability requirements. The amplitude and phase stabilities of 0.07%(RMS) and 0.35 deg(RMS) respectively, are required for ILC [1] For the acceleration, the ILC utilizes 1.3GHz superconducting RF cavities, operating at an average gradient of 31.5MV/m. The RF system will be organized in approximately 400 RF stations. Each RF station is composed of one 10MW multi beam klystron driving 39 superconducting cavities. The feedback control is implemented to compensate the non repetitive disturbance and measurement noise. As only a single klystron is used to drive 39 cavities, the digital LLRF control system has to control the vector sum of the accelerating field of those cavities. The vector sum is the sum of the complex vectors representing the accelerating fields of all cavities. The size of one RF station in the ILC is approximately 60m in length, which may add a delay to the signal transmission from cavity to digital LLRF control system. One possible solution to reduce this problem is to distribute the LLRF control system into several sub systems, in a master slave configuration. The slave LLRF control systems calculate partial vector sums from the corresponding cavities and are placed near the cavities to shorten the signal transmission lines. The partial vector sums from all slave LLRF control systems are sent to the master LLRF control system via an [email protected] Figure 1: STF layout consists of normal conducting photocathode RF gun, two superconducting 9 cell cavities in the capture cryomodule driven by 800 kW klystron, eight superconducting 9 cell cavities (cavity number 1 8) in the CM 1 cryomodule, four superconducting 9 cell cavities in the CM2a cryomodules (cavity number 9 12) Both CM 1 and CM 2a cryomodules are driven by one 10MW multi beam klystron. optical communication link. One issue in this connection is the additional delay to the control loop caused by optical communication link, which may lead to system instability. This paper presents an evaluation of the digital LLRF control system with a master slave configuration and an investigation to confirm the effect of the optical communication link delay on the RF stabilities. The demonstration of the minimum setup of digital LLRF control system with the master slave configuration for the ILC was conducted at Superconducting RF Test Facility (STF) High Energy Accelerator Research Organization (KEK) during the cavity conditioning in the autumn of 2016. The layout of the STF is illustrated in Figure 1. A total of twelve cavities in two cryomodules, CM 1 and CM 2a, were installed as the STF 2 project [2] DIGITAL LLRF CONTROL SYSTEM WITH MASTER SLAVE The LLRF control systemwith master slave configuration will be adopted in ILC. Figure 2 shows the proposed system for one RF station. As a slave, the LLRF front end controller calculates a partial vector sum from the corresponding cavities and the result is sent to the central LLRF controller as a master, where the total vector sums are calculated and the klystron output are controlled. In order to accommodate large data transfer from the front end to the central system, an optical communication link is used. The minimum setup of the digital LLRF control system with master slave configuration for ILC was built at STFTHPAB116 Proceedings of IPAC2017, Copenhagen, Denmark ISBN 978 3 95450 182 3 3992 Co py rig ht (c) 20 17 CC B Y3. 0 an d by th er es pe ct iv ea ut ho rs 06 Beam Instrumentation, Controls, Feedback and Operational Aspects T27 Low Level RF Figure 2: Digital LLRF control system with master salve configuration for the ILC. As a slave, the LLRF front end controllers directly measure the signals from corresponding cavities and send the result to central LLRF controller as a master [1] KEK, which is illustrated in Figure 3. The 1300MHz signals from the cavities are down converted by mixing with 1310MHz local oscillator (LO) to get a 10MHz intermediate frequency (IF) After being digitized by the analog todigital converter (ADC) the IF signal is converted into an in phase component (I) and quadrature phase component (Q) [3] In the slave digital LLRF board, the partial vector sum of VS2 from corresponding cavities are calculated and sent to the master digital LLRF board through an optical communication link with an approximate length of 20m. In the master digital LLRF board, the total vector sum from partial vector sum of VS1 and VS2 is calculated. The delay introduced by the optical communication link can be compensated by introducing an additional delay in the partial vector sum of VS1 through the DLY module. To suppress the parasitic modes in the multi cell cavities, a fourth order conjugate poles digital infinite impulse response (IIR) filter [4] with a bandwidth of 250 kHz was implemented after the total vector sum calculation. The feedback and feedforward control algorithms are also performed in the master LLRF board. The digital signal is then converted into analog by a digital to analog converter (DAC) and is fed to the I/Q modulator to modulate the 1.3GHz RF signal from the master oscillator (MO) This signal is then used to drive the klystron, which drives the cavities. Both master and slave board are MTCA.4 standard hardware with 14 ch 16 bit AD9650 ADC (Analog Device, Inc. 2 ch 16 bit AD9783 DAC (Analog Device, Inc. and two FPGAs, Zynq 7000 and Spartan 6 (Xilinx Inc. These boards employ 162.5MHz for FPGA clock and 81.25MHz for ADC/DAC clock.", "author_names": [ "Sigit Basuki Wibowo", "Na Liu", "Toshihiro Matsumoto", "Shinichiro Michizono", "Takako Miura", "Feng Qiu" ], "corpus_id": 51805666, "doc_id": "51805666", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Evaluation of Digital LLRF Control System Performance at STF in KEK", "venue": "", "year": 2017 }, { "abstract": "Abstract This paper presents a Low Cost Flexible Platform (LCFP) for measuring and characterizing photodetectors. This LCFP can characterize simultaneously up to 16 photodetectors and is composed by two main electronic circuit boards: a Transimpedance Amplifier Board (TIAB) and a Development Board (DevB) The TIAB was designed and optimized to reduce the noise increase, in order to convert photocurrents into voltages and at the same time, allowing the gain selection between one of the three values: 1 x 10 5 (low gain, LG) 1 x 10 6 (medium gain, MG) and 1 x 10 7 (high gain, HG) The DevB is composed by 16 analog inputs, 54 digital inputs/outputs and an internal Analog to Digital Converter (ADC) It is possible to digitally change the Upper End Voltage (UEV) of the ADC's range to voltages below +5 V. The DevB can convert into the digital domain each one of the 16 analog signals from the TIAB with a resolution of 48.9 nA, 4.9 nA and 0.5 nA for the highest value of UEV +5 V) and when either LG, MG or HG is selected, respectively. The measured data can be acquired in real time with LabView software, which allows the real time monitoring of the photocurrents for individual elements in the photodetector both through a numeric and graphical display. The light intensity can be defined by 8 digital outputs allowing 256 light intensity increments/steps from 0 to a maximum defined (by the lamp's manufacturer) light intensity. This LCFP can be used in industry to make quality control, e.g. when different test conditions are applied to the optical sensors/photodetectors and the user/customer need to quickly check if the response or performance is acceptable or resulted on any significant drifts. All these features combined with the low cost under 1400 EUR makes this LCFP a suitable tool to quickly evaluate the performance of optical sensors/photodetectors.", "author_names": [ "Jose Miguel Gomes", "Jose Higino Gomes Correia", "Joao Paulo Carmo" ], "corpus_id": 110848274, "doc_id": "110848274", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "A Low Cost Flexible Platform (LCFP) for characterization of photodetectors", "venue": "", "year": 2015 }, { "abstract": "Purpose: To determine differences in overall tumor responses measured by volumetric assessment and bioluminescence imaging (BLI) following exposure to uniform and nonuniform radiation fields in an ectopic prostate tumour model. Materials and Methods: Bioluminescent human prostate tumor xenografts were established by subcutaneous implantation into male mice. Tumors were irradiated with uniform or non uniform field configurations using conventional in vivo irradiation procedures performed using a 225 kVp generator with custom lead shielding. Tumor responses were measured using Vernier calipers and by BLI using an in vivo imaging system. Survival was defined as the time to quadroupling of pre treatment tumor volume. Results: The correlation between BLI and tumor volume measurements was found to be different for un irradiated (R 0.61) uniformly irradiated (R 0.34) and partially irradiated (R 0.30) tumors. Uniformly irradiated tumors resulted in an average tumour growth delay of 60 days with median survival of 75 days, compared to partially irradiated tumors which showed an average growth delay of 24 days and median survival of 38 days. Conclusions: Correlation between BLI and tumor volume measurements is lower for partially irradiated tumors than those exposed to uniform dose distributions. The response of partially irradiated tumors suggests non uniformity in response beyond physical dose distribution within the target volume. Dosimetric uncertainty associated with conventional in vivo irradiation procedures prohibits their ability to accurately determine tumor response to non uniform radiation fields and stresses the need for image guided small animal radiation research platforms. INTRODUCTION Small animal models are a fundamental tool for robust preclinical radiobiological investigations. Technological advances in the clinic, such as intensity modulated and image guided radiotherapy, have significantly outpaced those for the irradiation of laboratory animals under experimental conditions which has commonly been performed using fixed kilovoltage sources with custom lead shielding for beam targeting and sparing of normal tissues (Hillman et al, 2001; Know et al, 1992) This translational gap between experimental radiobiology and radiation oncology has been narrowed with the implementation of small animal image guided radiation research platforms (Verhaegen et al, 2011; Zhou et al, 2010; Wong et al, 2008) which combine high resolution cone beam computed tomography (CBCT) with orthovoltage radiation sources for accurate beam targeting allowing treatment of a defined target through a process analogous to that of contemporary clinical practice. The implementation of these platforms in the laboratory represents a significant advancement for in vivo radiobiological investigations enabling preclinical evaluation of novel regimes including hypofractionation, dose painting and drug radiation combinations. Furthermore, the development of small animal radiation research platforms with on board optical imaging will offer significant potential in radiation biology. A range of optical imaging and spectroscopy methods are widely used for radiobiological studies to determine cellular responses at the molecular level (Palmer et al, 2012) Bioluminescence imaging (BLI) is a highly sensitive, non invasive in vivo imaging modality which measures photons generated by a luciferase reporter gene in the presence of the D luciferin substrate injected prior to imaging (Inouye et al, 2010) BLI has been used to assess tumour burden in a range of preclinical models for localised and metastatic disease (O'Neill et al, 2010; Tuli et al, 2012; Al Nakouzi et al, 2012) however, its application in monitoring the efficacy of radiation exposure responses has been limited (Lee et al, 2010) In the present study, we aimed to compare tumour volume and BLI measurements to determine differences in overall tumor response following exposure to uniform and nonuniform radiation fields in an ectopic prostate tumor model. This study also sought to provide in vivo support for the presence of out of field effects under non uniform dose distributions. MATERIALS AND METHODS Cell culture PC 3 luc2 Bioware Ultra (Caliper Life Sciences, Runcorn, United Kingdom) is a stably transfected luciferase expressing variant of the human prostate cancer cell line PC 3 (Kaighn et al, 1979) Cells were grown in RPMI (Roswell Park Memorial Institute) 1640 medium with 10% fetal bovine serum, 1% penicillin streptomycin (Gibco, Paisley, Scotland, UK) and maintained at 37degC in a humidified atmosphere of 95% air 5% CO2. Animals, tumor implantation and maintenance 6 8 week old male Fox Chase SCID (Severe combined immunodeficient) mice (Charles River Laboratories, Oxford, United Kingdom) were used as a xenograft model for PC 3luc2 cells. 1.5 x 106 cells in 100 ml of PBS (phosphate buffered saline) were implanted intra dermally on to the flank of animals under inhalant anaesthesia. 5 animal were assigned to each experimental group (control, uniform irradiated, partially irradiated) Animals received food and water ad libitum. All experimental procedures were carried out in accordance with United Kingdom Home office approved protocols for in vivo experimentation. Irradiation procedure Tumors were grown for 4 8 weeks until reaching a pre treatment volume of around 100 mm3. Animals were assigned to three treatment groups, un irradiated controls, 8 Gy irradiated animals delivered as a uniform field and 8 Gy irradiated animals delivered as non uniform field in which 40 60% of the tumor volume was irradiated. Animals were restrained and custom lead shielding used to expose the complete or partial tumour volume to 225 kVp X rays using a X Rad 225 generator (Precision X ray Inc, North Branford, Connecticut, USA) A dose profile was generated using Gafchromic RTQA2 film (Ashland, Covington, Kentucky, USA) placed under the lead shielding which show scattered dose fell to less than 10% of the target dose within 1 cm off axis as shown in figure 1. Animals were irradiated at a dose rate of 0.52 Gy min 1. Tumour volume measurements and BLI Tumor volume was determined three times a week from Vernier caliper measurements in three orthogonal dimensions. Tumour bearing mice were imaged weekly using an IVIS 100 (Caliper Life Sciences) Animals were intraperitoneally injected with Dluciferin potassium salt (Caliper Life Sciences) at a concentration of 150 mg/kg and imaged 15 minutes after injection as determined from BLI kinetic studies in the same tumor model. The distribution of detected photons was overlaid onto a grayscale photographic image and a region of interest (ROI) manually selected. Signal intensity was quantified in photons/second/squared centimetre/steradian (p/s/cm2/Sr) for a ROI selected manually by applying the same threshold to each of the images using Living Image Software (Caliper Life Sciences) Statistical Analysis The correlation between tumour volume and BLI measurements was assessed using a linear regression of the form yy mmmm cc, where x is the measured volume, y the BLI value, m the slope and c the y intercept of the linear fit of the data. Significant correlation was evaluated using a two tailed t test on m, with a significance threshold of 0.05. All calculations were carried out using (GraphPad Prism, Version 5.01) RESULTS Correlation of tumor volume and BLI measurements Correlation of tumor volume and BLI measurements was determined for control, uniformly irradiated and partially irradiated tumours in a heterotopic prostate xenograft model. Photon emission from a manually selected region of interest showed maximum flux at 15 20 minutes after intraperitoneal injection of D luciferin in animals pretreatment. Control and irradiated animals showed no significant difference in the kinetics of bioluminescence signal at the beginning of the experiment or when maximum tolerated tumour volume was reached at the end of the experiment (data not shown) Comparison of BLI and tumour volume for control, uniformly irradiated and partially irradiated tumours is shown in figure 2. Linear regression analysis showed significant correlation between tumor volume and BLI for control tumors (R 0.6123) A less strong correlation between tumor volume and BLI was observed for uniformly irradiated tumours (R 0.3417) and the least significant correlation shown for partially irradiated tumors (40 60% tumour volume; R 0.3063) Significance testing of these correlation coefficients using a t test indicated statistically significant correlation for control (p 0.01) and uniformly irradiated animals (p 0.02) but no significant relationship for partially exposed tumors (p 0.08) Tumor growth delay and overall survival Tumor volume measurements are shown for control, uniformly irradiated and partially irradiated animals in figure 3a. Comparing the data for control with uniformly irradiated tumours showed a significant growth delay of around 60 days which is reflected in the median survival of 14 and 75 days respectively as shown in figure 3b. Comparison of control with partially uniformly irradiated tumours showed a significant growth delay of around 24 days which is reflected in the median survival of 14 and 38 days respectively as shown in figure 3b. The mean fractional uncertainty in tumor volume measurements was found to be 0.12 for control animals compared to 0.26 for partially irradiated and 0.24 for uniformly irradiated animals. DISCUSSION This study aimed to determine differences in the overall tumor response measured by volumetric assessment and BLI in un irradiated and irradiated tumors exposed to uniform or non uniform radiation fields. These experiments were conducted in the context of assessing BLI as a means to determine the effective spatial dependency of radiobiological effects occurring outside of the primary treatment field and to assess if this could be achieved", "author_names": [ "K T Butterwortha", "K M Redmonda", "S J McMahona", "A J Coleb", "H O McCarthyc", "", "M O'Sullivanb", "A R Hounselld", "K M Prisea" ], "corpus_id": 12245383, "doc_id": "12245383", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Conventional in vivo irradiation procedures are insufficient to accurately determine tumor responses to non uniform radiation fields", "venue": "", "year": 2016 }, { "abstract": "A prototype wireless guided wave inspection system is developed to inspect layered structures such as aircraft wing. The system includes a stationary antenna and an active antenna as transceivers, an on board antenna as transponder, and PVDF comb transducers for generating and receiving ultrasonic Lamb waves. Preliminary experiments on a 0.8mm aluminium plate with a 12mm long, 50% through wall depth crack clearly demonstrated its feasibility of defect detection. Potential applications on an E2 plane wing section are also presented. This system showed great potential of remote, leave in place and in service defect detection and condition monitoring. Introduction: The flight environment of an aircraft is usually very harsh due to large changes in humidity, temperature, pressure, speed, and loading conditions. These effects cause a lot of stress to aircraft frame. As a result, corrosion, delamination, cracks, disbonds, and other failures creep in once the aircraft is in service for some time. Fault diagnosis and prognosis is very important in health monitoring or condition based maintenance of the aircraft structures. If one can measure the degradation of a component before it actually fails, it will provide ample time for maintenance engineers to schedule a repair, and to purchase or fabricate replacement components before the components actually fail. The end result will be lower cost and higher availability. Ultrasonic guided waves have been used in non destructive inspection (NDI) of various defects in aircraft structures, with major advantages like fast scanning capabilities, low cost, and long range inspection. Small and reliable guided wave sensors can also be leave in place on the structures for online monitoring, which is more convenient for real time damage evaluation. All current data acquisition techniques, however, still rely on cable connections from a waveform generator to the inspection sensors, and then to a waveform displayer or oscilloscope for analysis. In this paper, we proposed a novel wireless system for structural integrity monitoring of an aircraft. The prototype system includes a passive antenna as a transmitter, an on board antenna as transponder, a PVDF comb transducer for generating and receiving ultrasonic Lamb waves in a layered structure, and a portable active antenna as a receiver. A series of experiments on a 0.8mm thick aluminium plate with a 12mm long, 50% through the wall crack clearly showed its feasibility in defect detection. Conventional wired approach and semi wireless approach are also presented for comparison. Some practical leave on board antennae for aircraft wings are also discussed, along with preliminary experiments. Approaches: One of the objectives of this study is that NDI sensors should be low cost, compact, passive, conformable to the aircraft structure, and can be interrogated in a wireless manner. The wireless capability allows the aircraft to be monitored all the time. Boeing has performed an internal study, which concludes that 85% of maintenance effort is spent on tearing down and re assembling the components. Only 15% of labour is spent on actual inspection. Hence the maintenance cost can be saved significantly by a wireless leave in place approach. For this objective to be materialized, we proposed a technical approach as shown in Figure 1. That is, a PVDF guided wave sensor is attached to the test structure, with its input/output connected to an on board antenna to feed in interrogate electrical signal and send out its response. The interrogate signal can be transmitted by a transmission antenna through a cable connected to the signal generator, and the return signal captured by a receiving antenna cable connected to a signal receiver. In this case, both the transmission and receiving antennae can be moved around and collect information about the health status of the structure. The conventional wired approach does not use antennae as information transponder; usually co axial cables are utilized to connect the signal generator, the sensor and the signal receiver together and it is the state of practice in industry. The choice of PVDF sensor is obvious since it is low cost, compact, passive, conformable to the test structure, and easy installation. We will discuss more about its design and utilization in the next subsection. Ultrasonic guided wave Crack Signal generator Signal reciever PVDF comb transducer Radiated and returned signal FIGURE 1 The schematic view of wireless inspection system for crack detection. 45.8cm PVDF Comb Transducer Crack Excited Lamp Wave 15.3cm", "author_names": [ "X Zhao", "Chiman Kwan", "Kwai Man Luk" ], "corpus_id": 14561359, "doc_id": "14561359", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "WIRELESS NONDESTRUCTIVE INSPECTION OF AIRCRAFT WING WITH ULTRASONIC GUIDED WAVES", "venue": "", "year": 2004 }, { "abstract": "This paper presents non contact ultrasonic imaging techniques with air coupling. The work is conducted as a part of the German research project MaTech. Project partners are Airbus, Bremen, IntelligeNDT, Erlangen, Ingenieurburo Dr. Hillger, Braunschweig, the Technical University of Hamburg Harburg and DLR, Braunschweig, as a subcontractor. A modular and open ultrasonic imaging system (demonstrator III) which provides the capability for basic research of air coupled ultrasonic techniques for composites has been developed. Highlights are: a freely programmable transmitter, fast full wave data recordings (12 bit) and software Cand D scans. Especially promising testing results can be achieved by the application of suitable transmitter signals and processing of the received signal. In this paper, both frequency modulated and coded signals are considered for transducer excitation. This works particularly well for broadband air coupled transducers, for which the signal is chosen adaptively. For the received signal, a matched filter processing is applied depending on the transmitter signal. Measurement results show a significant improvement of the signal to noise ratio especially for thicker components. Introduction: The increase of composite materials for aircraft applications requires a growing need for NDT. The aircraft industry is using more and more thick CFRPand CFRP sandwich components with honeycomb and foam core. Those materials are highly attenuative. Sandwich materials can only be penetrated with frequencies in a range of about 50 to 500 kHz. The airborne ultrasonic technique avoids the disadvantages of the common ultrasonic technique with coupling liquid or coupling paste like time consuming cleaning, incoming water, air bubbles in immersion technique, etc. [14] On the other hand, the acoustic impedance mismatch between solids and gas (air) produces an amplitude loss of more than 150 dB using a standard ultrasonic equipment. Therefore special transducers with an impedance matching to air, a powerful excitation of the sender and a matched ultra low preamplifier are required. Results: Ultrasonic system. The developed air coupled ultrasonic imaging system USPC 4000 AirTech (Fig. 1) is a further development of the \"demonstrator 3\" [5] of the MaTech project. This system provides high pulse repetition frequencies in order to get high scanning speeds. The hardware built in an industrial PC with Windows operating system consists of programmable high power pulser with a digital arbitrary generator, an ultra low noise preamplifier, a main amplifier and a ADC board with a resolution of 12 bits. All measuring functions such as amplitude (gated peakdetector) and time of flight measurements are carried out by software. The system does not only provide C scanning but also full wave scans with software A B C Dscans. Additional functions are echotechnique (in order to measure the distances between the transducers and the specimen) and the application of chirp and coded signals. The software also enables digital filters for the enhancement oft results. The system is working with transducers from different manufactures. Fig.1: Block diagram of USPC 4000 AirTech Transducers Several transducers from different manufactures have been evaluated for ultrasonic imaging. The most interesting parameters are sensitivity, centre frequency, bandwidth, focus point and beam diameter. Most of them are resonant transducers with a small bandwidth in order to get a high efficiency. A few of them showed side lobes in their sound fields. For optimising the distances between transducers and specimen, it is useful to record the sound field with a ball reflector. In order to get a high power broadband pulse, a stack transducer [6] (Fig. 2) has been investigated. This kind of transducer consists of eight elements, which are acoustically coupled and electrically insulated. At the back wall of the piezo element 1, an acoustic damping is situated, at the front (sound output, element 8) an impedance matching to air is situated. All elements are excited with delayed pulses S1 to S8. The delay times t2 to t8 are adjusted in the way that the passing pulse from element 1 through element 2 to 8 is amplified by the pulses S2 to S8. In the ideal case, the output of the element 8 provides an 8 fold higher pulse compared with a standard transducer. This technique can also be applied on the receiver side. The receiver stack transducer built in the same way, delivers 8 delayed pulses which have to be added with the right phases. Theoretically, a gain of 18 dB can be reached in comparison with a single element transducer on the receiver and on the transmitter side. For this kind of stack transducer, an ultrasonic system with eight channels has been developed. But the results show some disadvantages: The acoustic coupling between eight elements cause a ,ringing\" so that no single highly damped pulse has been generated. Therefore, the echo technique could not be used. Also the impedance matching to air was not very successful, so that the sensitivity s, defined by:", "author_names": [ "Wolfgang Hillger", "Malte Ahrholdt", "Herrmann Rohling", "Rudolf Henrich" ], "corpus_id": 111931679, "doc_id": "111931679", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Non Contact Ultrasonic Imaging Techniques for Composite Components", "venue": "", "year": 2004 }, { "abstract": "Noncardiac chest pain is characterized by recurrent and often incapacitating chest pain without demonstrable cardiac abnormality. As many as 30% of patients with suspected angina may have this condition [1] In the United States, the annual incidence is estimated to be 180 000 cases [2, 3] Although some patients are reassured by the absence of a definable abnormality, many continue to have pain that prompts frequent visits to physicians and emergency departments and even results in hospitalization [4, 5] In many cases, the esophagus has been determined to be the source of such pain. Esophageal manometry can identify motor dysfunction in as many as 25% of patients with noncardiac chest pain [6, 7] and additional provocative tests show motor and other abnormalities in another 15% to 25% [6 10] Most such patients have gastroesophageal reflux disease [3] Some studies of the sensations evoked by balloon distention in the esophagus have suggested that 48% to 60% of such patients have altered sensory perception [11 13] but other studies have not confirmed this finding [9, 10, 14] Most studies of esophageal motor function have examined the contractile properties of the esophagus, but little attention has been paid to the biomechanical and sensory properties, primarily because of technical limitations [15 17] A new technique, impedance planimetry, allows investigation of sensory and biomechanical properties in the intact human gut [15, 16, 18, 19] This technique provides a way to assess the cross sectional area of the lumen in a selected plane at a range of distending pressures. It also permits quantification of the resistance offered by the biomechanical and contractile properties of the wall and of the sensory responses that are provoked by balloon distention. We used impedance planimetry to determine whether a sub group of patients with unexplained chest pain has abnormal biomechanical esophageal muscle properties and abnormal esophageal sensory nerve function. Methods Participants We studied 24 consecutive patients with unexplained noncardiac chest pain who were seen on an outpatient basis: 10 men and 14 women (mean age, 48 years [range, 30 to 74 years] All patients were referred by cardiologists after extensive cardiac evaluations showed no cause for the chest pain and, in many instances, after various empiric therapies proved ineffective. Patients had no comorbid illnesses and had either normal coronary arteries or insignificant coronary artery disease as shown by results of angiography, stress thallium testing, or stress technetium 99m methoxy isobutyl isonitrile (MIBI) In addition, all patients had extensive gastrointestinal evaluations. The results of these evaluations included normal findings on upper gastrointestinal endoscopy with esophageal biopsy, normal esophageal manometric results, and either normal results of 24 hour pH study or no response to 6 weeks of omeprazole, 20 mg per day. Patients were included only if they had at least one episode of chest pain per week and if their symptoms had persisted for more than 3 months. We also studied 12 healthy controls, 5 men and 7 women (mean age, 35 years [range, 24 to 63 years] who were recruited by a hospital advertisement. The controls were asymptomatic, were not taking any medication, had not had any previous thoracic or gastrointestinal surgery, and had normal physical examinations. All participants gave written informed consent, and the Human Investigation Review Board of the University of Iowa College of Medicine approved the study. Impedance Probe and Measuring System The equipment, which consisted of a probe and a signal processing system, has been described in detail elsewhere [15, 16, 19] The flexible plastic probe, 6 mm in diameter, contained four ring electrodes (two outer and two inner electrodes) and five side holes. A thin latex balloon, 4.5 cm long, was tied around the probe to enclose the four ring electrodes and three of the side holes (Figure 1) Two of these were infusion side holes that were used to distend the balloon, and the third was a perfusion side hole that was used to measure intraballoon pressure. The remaining side holes, one located 2.5 cm proximal to the balloon and the other located 2.5 cm distal to the balloon, were used to measure intraesophageal pressures. The side holes were perfused with 0.018% NaCl solution at a rate of 0.2 mL/min, and the intraluminal pressures were measured using a low compliance pneumohydraulic perfused system (Arndorfer, Milwaukee, Wisconsin) connected to external transducers (Gould, Inc. Essex, United Kingdom) The leveling container, a 400 mL plastic jar half filled with 0.018% NaCl, was connected to the probe with a plastic tube. The signal processing system (Figure 1) consisted of a generator that gave a constant alternating current of 100 A at 5 KHz, an amplifier, an impedance detector, an analog digital converter, and a computer [15, 16, 19] Figure 1. Schematic representation of the probe and the signal processing system used for impedance planimetry of the esophagus. Study Protocol All participants were studied after an overnight fast. Oropharyngeal anesthesia was achieved with a local spray of dyclonine hydrochloride (Dyclone, Astra, Westboro, Massachusetts) The lubricated probe was passed through the mouth until its tip was located 55 cm from the teeth. Participants were asked to lie on a bed, which was tilted at the head end by 30 degrees. After a rest period of 10 minutes, the catheter was gradually withdrawn until the balloon lay across the lower esophageal sphincter. The lower esophageal sphincter was identified as a zone of high resting pressure that decreases with swallows. The catheter was removed and taped in position so that the balloon lay 10 cm above the lower esophageal sphincter, where all measurements were obtained. After a second rest period of 10 minutes, the balloon pressure was set at 0 according to the resting intraesophageal pressure by adjusting the height of the leveling container, which was adjacent to the participant but behind a screen. Thus, participants were blinded to the degree of inflation. Next, the balloon pressure was increased in steps of 5 cm H2O to 50 cm H2O or greater by raising the leveling container and infusing 0.018% NaCl (at 37 C) into the balloon. After each distention, the balloon was deflated by lowering the leveling container and was reinflated after a rest period of 3 minutes. Each inflation was maintained for 3 to 5 minutes or until the cross sectional area reached a new stable baseline between reactive contractions. At this steady state, the cross sectional area was measured and the sensory responses were noted. Participants were given a symptom chart and were asked to grade their sensation as follows: grade 0, no sensation; grade 1, a sensation of fullness or distention; grade 2, moderate (tolerable) discomfort; and grade 3, severe pain. Because no controls had discomfort or pain at inflation pressures as great as 50 cm H2O, serial inflations of the balloon were continued until the controls reported pain or until a pressure of 65 cm H2O was reached. In the patient group, the inflations were continued until typical chest pain was evoked or until a pressure of 50 cm H2O was reached. During inflations, participants were asked to refrain from swallowing and to signal the onset of reflex swallows. Reflex swallows were noted to distinguish primary (that is, aborad) propagating contractions, which are initiated by swallowing, from secondary peristalsis, which consists of aborad propagating contractions induced by local distention of the esophagus. Measurements and Data Analysis The balloon cross sectional area was measured according to the field gradient principle [20 22] When a current, I, is induced by the two outer ring electrodes in a cylinder of conducting medium, the potential difference, V, between the two inner (detection) electrodes is V equals I R (Ohm's law) where R is the impedance of the conducting substance. R can also be expressed as d c1 the cross sectional area1, where d is the distance between the detection electrodes and c is the conductivity of the fluid. If I, d, and c are constants, V is inversely proportional to the cross sectional area. The computer software provided output that was directly proportional to the cross sectional area. The data for the cross sectional area and intraluminal pressure were stored on diskettes. The records, visualized off line on a computer, were analyzed with a software program by an author who was blinded to the participants' clinical details and results of sensory function. The following are definitions of and formulas used to calculate the variables. Sensory Responses The balloon pressure that induced first sensations of fullness, moderate discomfort, and pain were noted for each participant, and the mean values for the threshold pressures that induced each sensation were calculated. Passive Biomechanical Properties Cross sectional area: At each level of balloon inflation, the radius was calculated from the new steady state baseline cross sectional area. Because previous studies [18, 19, 23] had shown that the measurements of the cross sectional area conform to the linear portion of the calibration curve at pressures as great as 40 cm H2O, and because 35% of patients could not tolerate balloon distention beyond this level, the cutoff pressure for calculations of biomechanical variables was 40 cm H2O. Circumferential wall tension (T) The total force applied to stretch a segment of the wall was calculated [15, 16] as T r dP, where r is the balloon radius (r square root of the cross sectional area P 1) and dP is the transmural pressure difference (Law of Laplace) Transmural pressure was defined as the difference between the balloon pressure and the resting pressure in the esophagus, with the assumption that esophageal intraluminal pressure at rest is the same as intrathor", "author_names": [ "S S C Rao", "Hans Gregersen", "Bernard Hayek", "Robert W Summers", "James Christensen" ], "corpus_id": 45775343, "doc_id": "45775343", "n_citations": 193, "n_key_citations": 9, "score": 0, "title": "Unexplained Chest Pain: The Hypersensitive, Hyperreactive, and Poorly Compliant Esophagus", "venue": "Annals of Internal Medicine", "year": 1996 }, { "abstract": "ILC work at Illinois has concentrated primarily on technical issues relating to the design of the accelerator. Because many of the problems to be resolved require a working knowledge of classical mechanics and electrodynamics, most of our research projects lend themselves well to the participation of undergraduate research assistants. The undergraduates in the group are scientists, not technicians, and find solutions to problems that, for example, have stumped PhD level staff elsewhere. The ILC Reference Design Report calls for 6.7 km circumference damping rings (which prepare the beams for focusing) using \"conventional\" stripline kickers driven by fast HV pulsers. Our primary goal was to determine the suitability of the 16 MeV electron beam in the AO region at Fermilab for precision kicker studies.We found that the low beam energy and lack of redundancy in the beam position monitor system complicated the analysis of our data. In spite of these issues we concluded that the precision we could obtain was adequate to measure the performance and stability of a production module of an ILC kicker, namely 0.5% We concluded that the kicker was stable to an accuracy of ~2.0% and that we could measure this precision to an accuracy of ~0.5% Asmore a result, a low energy beam like that at AO could be used as a rapid turnaround facility for testing ILC production kicker modules. The ILC timing precision for arrival of bunches at the collision point is required to be 0.1 picosecond or better. We studied the bunch to bunch timing accuracy of a \"phase detector\" installed in AO in order to determine its suitability as an ILC bunch timing device. A phase detector is an RF structure excited by the passage of a bunch. Its signal is fed through a 1240 MHz high Q resonant circuit and then down mixed with the AO 1300 MHz accelerator RF. We used a kind of autocorrelation technique to compare the phase detector signal with a reference signal obtained from the phase detector's response to an event at the beginning of the run. We determined that the device installed in our beam, which was instrumented with an 8 bit 500 MHz ADC, could measure the beam timing to an accuracy of 0.4 picoseconds. Simulations of the device showed that an increase in ADC clock rate to 2 GHz would improve measurement precision by the required factor of four. As a result, we felt that a device of this sort, assuming matters concerning dynamic range and long term stability can be addressed successfully, would work at the ILC. Cost effective operation of the ILC will demand highly reliable, fault tolerant and adaptive solutions for both hardware and software. The large numbers of subsystems and large multipliers associated with the modules in those subsystems will cause even a strong level of unit reliability to become an unacceptable level of system availability. An evaluation effort is underway to evaluate standards associated with high availability, and to guide ILC development with standard practices and well supported commercial solutions. One area of evaluation involves the Advanced Telecom Computing Architecture (ATCA) hardware and software. We worked with an ATCA crate, processor monitors, and a small amount of ATCA circuit boards in order to develop a backplane \"spy\" board that would let us watch the ATCA backplane communications and pursue development of an inexpensive processor monitor that could be used as a physics driven component of the crate level controls system. We made good progress, and felt that we had determined a productive direction to extend this work. We felt that we had learned enough to begin designing a workable processor monitor chip if there were to be sufficient interest in ATCA shown by the ILC community. Fault recognition is a challenging issue in the crafting a high reliability controls system. With tens of thousands of independent processors running hundreds of thousands of critical processes, how can the system identify that a problem has arisen and determine the appropriate steps to take to correct, or compensate, for the failure? One possible solution might come through the use of the OpenClovis supervisory system, which runs on Linux processors and allows a select set of processors to monitor the behavior of individual processes and processors in a large, distributed controls network. We found that OpenClovis exhibited an irritating amount of sensitivity to the exact version of the Linux kernel running on the processors, and that it was poorly equipped to help us sort through problems that arose through conflicts so deep in the operating systems of the processors. But once this issue was addressed, we found that it performed as expected, recognizing crashes and process (and processor) failures. less", "author_names": [ "George D Gollin", "M Davidsaver", "Michael Haney", "Michael Kasten", "Jason Chang", "Perry A Chodash", "Will Dluger", "Alex Lang", "Yehan Liu" ], "corpus_id": 109547167, "doc_id": "109547167", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "International Linear Collider Accelerator Physics R&D", "venue": "", "year": 2008 }, { "abstract": "The experience of large calorimeters, in passed and actual experiments shows that the calibration is an extremely long and methodic task, implying several redundant methods in hardware and software as well. If, as expected nowadays, the Higgs has a mass under 150 GeV, its discovery in gg decay by LHC experiments will rely heavily on the resolution of the ECAL. The precise measurement of these two gammas will depend in particular upon an accurate calibration (the constant term is expected 0.5% in CMS) and upon a precise g/e energy scale. The knowledge and the mastering of the calibration will play a major role. We describe here the electronic system, that has been developed at LAPP to update permanently the calibration of the electronic readout chain of CMS ECAL, during data taking. 1 The CMS ECAL and its read out The target characteristics of CMS ECAL make this project very challenging in terms of resolution, hadron rejection, particles isolation etc..Its characteristics are described in several publications [1,2,3] and I will only remember the principles of its read out As this crystal calorimeter is fully immerged in the magnetic field of 4 Teslas, the choice was made to read out the crystals by APD photodetectors. A very aggressive R&D has been sent since 4 years and is being concluded by the production of 120 000 of these detectors. The first pre production is actually under tests. Each crystal will be equipped with 2 Hamamatsu APD's, in parallel, and the read out is made by sets of 2 read out cards, grouping 5 channels each. On the read out card are implemented A/ 5 chips \"FPPA\" developed in Harris UHF1X process, which are multi gain shaping amplifiers (gains 1, 4, 8, 32) with a specific logic to indicate the first amplifier that does not saturates for the sampling (40 MHz) being made. The chosen amplifier is marked by 2 bits, added B/ 5 commercial flash ADC 12 bits (Analog Device AD 9042, previously developed for USAF, in Bipolar XFCB Process) that digitize the amplitude every 25 ns. C/ 5 serializers that convert the parallel 20 bits words (40 MHz) to a serial stream out (0.8GB.s) for the opto coupler. D/ One opto coupler, developed in CHFET ASGA process, that transmits the digital information through a set of 3 fibers to the Read Out System ECAL (ROSE) card that, in the control room, links the front electronic to the general DAQ and to the trigger. E/ One \"Control Chip\" (CTRL) developed in DMILL BICMOS process, that receives, from the ROSE card, through optical fibers, the adjustment parameters for the readout. It deserializes and dispatch them to individual chips. Apart from the DAC, all the chips are full custom and have been developed at CERN by Princeton group. The final version of the whole system has been put in test beam for the first time in August and the analysis is under way. 2The calibrations of ECAL The task can be divided into 3 general topics [4] 1. Before being mounted on the detector, all the supermodules will be pre calibrated on a dedicated electron test beam to provide an initial precise set of calibration coefficients for each channel. 2 During data taking, the day to day, channel to channel calibration inside a same region will be updated during sterile cycles of the machine by light injection and charge injection. This calibration is made by alignment of the response of individual channels belonging to a same region. A region can be defined as a group of channels sharing the same bunch of fibers. 3 The medium and long range (in time) absolute calibration of the whole detector will rely on W and Z decay measurements. The calibration of ECAL is then organized on several partially redundant methods: 1. Injections at the inner edge of the crystals of light pulses produced by two lasers and passing through a fiber distribution system: This system will follow the response of the ensemble crystal readout chain to light pulses along the time. The first pulse, at the middle of the scintillation spectrum (420 nm) will follow the shifts of the overall system (in particular due to loss of transparency of crystals under irradiation)[5,6] The second one, at 600nm is almost insensitive to transparency losses and will follow the APD gain and electronic shifts. 2 An independent system of charge injection at the input of the read out chain will follow the shifts of the readout chain and cross calibrate the different gains of the preamplifiers. 3. \"In situ\" calibration with physics events at low energy, the isolated electrons will be measured precisely by the tracker and their momentum compared with the response of the calorimeter. At medium energy (around 20 GeV) the W's and Z's will provide an absolute calibration for the whole detector. According to luminosity, this \"in situ\" calibration will need between a few days and a month during which the local calibrations will have to be adjusted. 3 The calibration by Charge injection The project consist of adding on the readout card a) one Test Pulse Logical System (TPLS) implemented inside the CTRL, b) one DAC, c) 5 injectors, producing on request a current pulse at the input of each FPPA. These pulses have a shape identical to the APD's one and their common amplitude is proportional to the order given to the DAC. The system has been developed at LAPP (Annecy) in DMILL process, with following requirements 1. no perturbation of the characteristics of the chain (in particular no add of correlated noise, no cross talk, nor any deterioration of characteristics) 2. at least as precise and reliable as the readout chain 3 robustness to eventual shifts due to irradiation damages 4. Use of existing supplies (0/5V) and very low power consumption 3.1 The Injector The injector is the most critical part of this system. It has to cover the total dynamic of the APD's (pick current of 4mA, and a full scale charge of 48 pC) with a linearity better than 0.5 It has to be radhard up to 10 n/cm and 3 Mrads in g (10 years of LHC irradiation) The shape is a fast negative fall followed by an exponential rise (t=15ns) with a technical dispersion in amplitude and time lower than 10% The PSRR (Power Supply Rejection Ratio) against the supply and the DAC line has to be as low as possible. Since 1998, we have made 5 generations of prototypes a first one in AMS to test the principle, then two in CMOS, one in CMOS Bipolar and a last version integrating the 5 channels in one chip. In the final design, the injector is made of 3 components 1. The trigger part, that adapt the PECL window signal (400ns width) received from the CTRL to levels compatible with the pulse generator stage. The edge of signals are also slightly reshaped to avoid the time jitter in the trigger of calibration pulses. 2 The amplifier that translates the voltage level produced by the DAC into a current level, transmitted to the pulse generator stage 3. The pulse generator is mainly a two branch bipolar circuit. The trigger splits the flowing current from one branch to the other one and the capacity Cout (60pF) previously charged is rapidly discharged and then recharged through Rout (250 O) and the preamplifier (Zi ~7 O) The decay time of the pulse is completely fixed by Rout Cout For precision and flexibility, the Cout has been placed outside the chip. Figure 1 Principle of the Injector 3.2 The DAC In a previous version, we have tested a commercial circuit, Analog Device AD 8582A in CB CMOS technology. This DAC is a parallel input, 12 bits, 0/4Volts, 5mA output, supplied on 0/5Volts, its dissipation is 5mW at rest. Its reference voltage level can be measured on an output pad. This chip has been extensively tested in lab and in irradiation beams. It fulfills the calibration requirements In a second step, a 10 bits DMILL version has been founded in view of assembling the whole project in one chip. This DMILL DAC is still under investigations due to process difficulties during foundry. 3.3 The control chip The control chip first amplifies the amplitude of the 40MHz clock and of the data's received from the optocoupler; then it recognizes, interprets and dispatches the orders to the different parts of the readout card. 4 The R&D 4.1 The tools Figure 2 shows the chain that has been mounted at LAPP to measure the linearity, the dispersion and the stability of different components of the project. This chain is based on a PC linked to a VME and CAMAC crates for charge measurements. It is also linked to a Keithley Multimeter 2020 by GPIB link for levels measurements. An overall monitor Labview(r) program makes systematic rampings on the DAC with charge and levels measurements at each step. The linearity of the injector has been measured in tension (at the edges of Rout) which is the most precise and in total integrated charge, after Cout In some runs, we have also verified by on a LECROY 9361 linked by GPIB that the shape was not affected. Figure 2 Principle of the Measurement chain For irradiation tests, we moved an identical chain on the different available sites. Figures 3 set up used for irradiation tests After a preliminary test on the Nuclear plan Ulysses at Saclay (IR1) we have used the SARA installation at Grenoble (France) (IR 2) and after it's shut down, the CERI installations at Orleans (IR 3,4 and 5) where the irradiation facility had been moved. These beams [7,8] produce neutrons by stripping of deutons on a thick beryllium target. The average energy of these neutrons is 6 MeV and the FWHM is 6 MeV. Theses beam have a photon contamination that has been evaluated to 3.6 kGy for an integrated dose of 2*10 n/cm The fluence depends on the distance to the target and can be adjusted up to 10 n/cm/ hour. We have also used the 72 MeV proton beam of PSI (Villigen, Switzerland) (IR 6 and 7) The correction parameter for protons is 2 and the equivalent integrated dose for this irradiation was 4 10 n/cm2. We have also used a photon Cobalt source facility at PSI to", "author_names": [ "Yong Wook Baek", "Jean Pierre Peigneux", "Pierre Yves David", "J P Mendiburu", "Joseph M Ditta", "D I Boget" ], "corpus_id": 10523690, "doc_id": "10523690", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Calibration chain developed at LAPP for the ECAL of CMS", "venue": "", "year": 2000 } ]

[ { "abstract": "BACKGROUND Thalassemia is one of most common monogenetic diseases in the south of China and Southeast Asia. Hemoglobin Bart's hydrops fetalis syndrome was caused by a homozygous SEA deletion in the HBA gene. Few studies has proved the potential of screen for Bart's hydrops fetalis using fetal cell free DNA. However, the number of cases is still relatively small. Clinical trials of large samples would be needed. OBJECTIVE In this study, we aim to develop a non invasive method of target captured sequencing and genotyping by Bayesian method using cff DNA to identify the fetal genotype in pregnant women who are at risk of having Hemoglobin Bart hydrops fetalis in a large scale study. STUDY DESIGN In total, 192,173 couples from 30 hospitals were enrolled in our study and 878 couples were recruited, among whom both the pregnant women and their husbands were detected to be carriers of Southeast Asian (SEA) type /aa) of a thalassemia. Prenatal diagnosis was performed by CVS, amniocentesis or cordocentesis using gap PCR considered as the golden standard. RESULTS As a result, we can found that the sensitivity and specificity of our non invasive method were 98.81% and 94.72% respectively, in the training set, as well as 100% and 99.31% respectively, in the testing set. Moreover, our method could identify all of 885 maternal samples with the SEA carrier and 36 trisomy samples with 100% of sensitivity in T13, T18 and T21 and, while 99.89% (1/917) and 99.88% (1/888) of specificity in T18 and T21, respectively. CONCLUSIONS Our method opens the possibility of early screening for maternal genotyping of a thalassemia, fetal aneuploidies in chromosomes 13/18/21, and Hemoglobin Bart hydrops fetalis detection in one tube of maternal plasma.", "author_names": [ "Jiexia Yang", "Chun-fang Peng", "Yi-ming Qi", "Xing-qiang Rao", "Fang-Fang Guo", "Ya-Ping Hou", "Wei He", "Jing Wu", "Yang-Yi Chen", "Xin Zhao", "Yu-nan Wang", "Haishan Peng", "Dong-mei Wang", "L Du", "Mingyong Luo", "Quan-fei Huang", "Hai-Liang Liu", "Aihua Yin" ], "corpus_id": 199507721, "doc_id": "199507721", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Noninvasive Prenatal Detection of Hemoglobin Bart hydrops fetalis via maternal plasma dispensed with parental haplotyping using the Semiconductor Sequencing Platform (SSP)", "venue": "American journal of obstetrics and gynecology", "year": 2019 }, { "abstract": "Nowadays, prenatal diagnosis is necessary for pregnant women. For the parents who are expecting a child, the genetic test may provide the information whether they are carrying rare gene mutations and whether they are at risk of passing them onto their offspring. However, the ultimate determination of genetic diseases often requires invasive procedures such as amniocentesis and chorionic villus sampling, which may cause fetal miscarriage. A noninvasive type of prenatal diagnosis needs to be developed in clinical practice to dispel safety concerns. In this paper, we will review the technical advancement of using maternal circulating nucleic acids as the sample in noninvasive studies, and highlight the utilization of next generation sequencing in the screening of genetic diseases.", "author_names": [ "Nancy Bo Yin Tsui", "Yuk Ming Dennis Lo" ], "corpus_id": 71388055, "doc_id": "71388055", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Noninvasive Prenatal Diagnosis Using Next Generation Sequencing", "venue": "", "year": 2014 }, { "abstract": "To the Editor: After the discovery of fetal DNA in maternal plasma, investigators reported different strategies for the noninvasive prenatal diagnosis of genetic diseases (1) Despite the advances in improving the analytical sensitivity of methods, distinguishing between fetal and maternal sequences remains very challenging, and the field of noninvasive prenatal diagnosis of genetic diseases has yet to attain a routine application in clinical diagnostics. An innovative strategy that has been reported is based on COLD PCR (coamplification at a lower denaturation temperature PCR),1 which exploits melting temperature T m) differences between variant or mismatched sequences and wild type sequences. This approach uses a critical denaturation temperature T c) lower than the T m to selectively amplify minority mutated alleles (2) We have developed assays for the identification of fetal paternally inherited mutations in maternal plasma. These assays use full COLD PCR for the detection of IVSI.110 (G>A) and Cd39 (C>T) HBB (globin, beta) gene mutations that cause b thalassemia. Full COLD PCR is based on the generation of heteroduplexes between mutant and wild type sequences. These heteroduplexes melt at lower temperatures than the wild type homoduplexes. They are selectively denatured at the T c and then subsequently amplified. Given that both the fetal and maternal DNA content in maternal plasma has been demonstrated to vary from pregnancy to", "author_names": [ "Silvia Galbiati", "Angela Brisci", "Faustina Lalatta", "Manuela Seia", "G Mike Makrigiorgos", "Maurizio Ferrari", "Laura Cremonesi" ], "corpus_id": 15960731, "doc_id": "15960731", "n_citations": 52, "n_key_citations": 4, "score": 0, "title": "Full COLD PCR protocol for noninvasive prenatal diagnosis of genetic diseases.", "venue": "Clinical chemistry", "year": 2011 }, { "abstract": "There is a great effort to find out the biological role of cell free nucleic acids (cfNAs) They are considered very promising targets in the diagnosis of genetic diseases. Non invasive sampling (liquid biopsy) has recently become a very popular method, and new molecular biological techniques have been developed for these types of samples. Application of next generation sequencing (NGS) and massively parallel sequencing (MPS) is spreading fast. These are the part of the arsenal of the modern prenatal genetic diagnostic laboratories by now. Cell free DNA based noninvasive prenatal testing accounts for more than half of the prenatal genetic tests performed, it is gradually replacing the invasive amniocentesis or chorionic villus sample based diagnostics. Besides that, new non coding RNAs are taking more attention: microRNAs (miRNAs) long non coding RNAs (lncRNAs) circular RNAs (circRNAs) are in the focus of the clinical research to detect the most common pregnancy associated diseases, like preeclampsia, fetal growth restriction, congenital heart diseases and gestational diabetes. The research is at advanced stage on the use of microRNAs, while lncRNAs and circRNAs are still promising targets. In this review, comprehensive information is given about the recent developments on this field.", "author_names": [ "Balint Nagy" ], "corpus_id": 195754925, "doc_id": "195754925", "n_citations": 13, "n_key_citations": 1, "score": 1, "title": "Cell free nucleic acids in prenatal diagnosis and pregnancy associated diseases", "venue": "EJIFCC", "year": 2019 }, { "abstract": "BACKGROUND Microdeletions and microduplications can occur in any pregnancy independent of maternal age. The spectrum and features of pathogenic copy number variants including the size, genomic distribution and mode of inheritance are not well studied. These characteristics have important clinical implications regarding expanding noninvasive prenatal screening for microdeletions and microduplications. OBJECTIVES The aim is to investigate the spectrum and characteristics of pathogenic copy number variants in prenatal genetic diagnosis and to provide recommendations for expanding the scope of noninvasive prenatal screening for microdeletions and microduplications. STUDY DESIGN This is a retrospective study of 1,510 pregnancies who underwent invasive prenatal diagnostic testing by chromosomal microarray analysis. Prenatal samples were retrieved by amniocentesis or chorionic villus sampling and sent to our prenatal genetic diagnosis laboratory for chromosomal microarray analysis. The risk of carrying a fetus with pathogenic copy number variants are stratified by the patients' primary indication for invasive testing. We searched the literature for published prenatal chromosomal microarray data to generate a large cohort of 23,865 fetus. The characteristics and spectrum of pathogenic copy number variants including the type of aberrations (gains or losses) genomic loci, sizes, and the mode of inheritance were studied. RESULTS Overall, 375/23,865 (1.6% fetuses carried pathogenic copy number variants for any indication for invasive testing, and 44 (11.7% of them involve 2 or more pathogenic copy number variants. A total of 428 pathogenic copy number variants were detected in these fetuses, of which 280 are deletions and 148 are duplications. 360 (84.1% were less than 5Mb in size and 68 (15.9% were between 5 10Mb. The incidence of carrying a pathogenic copy number variant in the high risk group is 1 in 36, and the low risk group is 1 in 125. Parental inheritance study results were available in 311 positive cases, 71 (22.8% were maternally inherited, 36 (11.6% were paternally inherited, and 204 (65.6% occurred de novo. CONCLUSION Collectively, pathogenic copy number variants are common in pregnancies. High risk pregnancies should be offered invasive testing with chromosomal microarray analysis for the most comprehensive investigation. Detection limits on size, parental inheritance, and genomic distribution should be carefully considered before implementing copy number variant screening in expanded noninvasive prenatal screening.", "author_names": [ "Matthew Hoi Kin Chau", "Ye Cao", "Ka Yin Yvonne Kwok", "Samantha Chan", "Yiu Man Chan", "Huilin Wang", "Zhenjun Yang", "Hoi Kin Wong", "Tak Yeung Leung", "Kwong Wai Choy" ], "corpus_id": 190526323, "doc_id": "190526323", "n_citations": 16, "n_key_citations": 2, "score": 0, "title": "Characteristics and mode of inheritance of pathogenic copy number variants in prenatal diagnosis.", "venue": "American journal of obstetrics and gynecology", "year": 2019 }, { "abstract": "BACKGROUND Non invasive prenatal diagnosis based on detection of fetal cell free DNA is limited when mother and father are both carriers for the same autosomal recessive mutation. OBJECTIVE Develop the semi nested Taqman real time PCR for quantification of alpha thalassemia 1 SEA type deletion allele in plasma of alpha thalassemia 1 SEA carriage pregnancies. MATERIAL AND METHOD Plasma DNA was extracted from six women who carried fetuses with normal, 11 with heterozygote alpha thalassemia 1 SEA type deletion and seven with Bart's hydrops fetalis. DNA was amplified using conventional PCR with the primary specific primer set for alpha thalassemia 1 SEA type deletion. PCR product was then subjected to the semi nested real time PCR using the secondary specific primer and Taqman probe set for alpha thalassemia 1 SEA type deletion. The standard curve was constructed using ten fold serial dilutions of conventional PCR product of the heterozygote alpha thalassemia 1 SEA type deletion. RESULTS Women who carried fetuses with Bart's hydrops fetalis displayed a trend toward higher mean copy number of alpha thalassemia 1 SEA type deletion allele vs. women who carried fetuses with normal and heterozygote, albeit not reaching statistical significance. CONCLUSION The maternally inheritedfetal allele present in maternal plasma is difficult to discern the fetal cell free DNA from a higher background DNA of the mother Thus, further investigation is needed to improve the diagnosis ofBart's hydrops fetalis using this technique.", "author_names": [ "Sakorn Pornprasert", "Kanyakan Sukunthamala", "Naowarat Kunyanone", "Sririchai Sittiprasert", "Khanungnit Thungkham", "Sumeth Junorse", "Khachonsilp Pongsawatkul", "Wisut Pattanaporn", "Chantip Jitwong" ], "corpus_id": 25672629, "doc_id": "25672629", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Semi nested Taqman real time quantitative PCR for noninvasive prenatal diagnosis of Bart's hydrops fetalis.", "venue": "Journal of the Medical Association of Thailand Chotmaihet thangphaet", "year": 2012 }, { "abstract": "Nowadays, prenatal diagnosis is necessary for pregnant women. For the parents who are expecting a child, the genetic test may provide the information whether they are carrying rare gene mutations and whether they are at risk of passing them onto their offspring. However, the ultimate determination of genetic diseases often requires invasive procedures such as amniocentesis and chorionic villus sampling, which may cause fetal miscarriage. A noninvasive type of prenatal diagnosis needs to be developed in clinical practice to dispel safety concerns. In this paper, we will review the technical advancement of using maternal circulating nucleic acids as the sample in noninvasive studies, and highlight the utilization of next generation sequencing in the screening of genetic diseases.", "author_names": [ "Liang Xu", "Rui Shi" ], "corpus_id": 30391432, "doc_id": "30391432", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Noninvasive Prenatal Diagnosis Using Next Generation Sequencing", "venue": "Gynecologic and Obstetric Investigation", "year": 2013 }, { "abstract": "Prenatal diagnostic technique is used to determine whether the unborn fetus is affected with a genetic disorder or other abnormality. This technique is generally carried out for a genetic disease that is not treata ble, in which the termination should be considered. This technique is also performed in cases that require im mediate action during the prenatal period and in conditions that can lead to morbidity or mortality of the mother. Prenatal diagnosis can be done by invasive and noninvasive methods. Invasive methods such as amni ocentesis and chorionic villus sampling (CVS) have a risk of causing disability and even death of the fetus. While noninvasive approach by ultrasound is not sufficiently accurate for the diagnosis of genetic diseases, therefore further fetal sampling is required. Noninvasive prenatal diagnosis is a new type of genetic testing done through taking fetal cells, fetal DNA and mRNA, which are found in maternal blood circulation. In this review, we present development of research, constraints, and potential clinical applications of these three methods for noninvasive sampling of the fetus.", "author_names": [ "Anak Agung Dewi Megawati" ], "corpus_id": 80829299, "doc_id": "80829299", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Potential Use of Fetal Genetic Material in Maternal Circulation for Prenatal Noninvasive Diagnosis of Genetic Disease", "venue": "", "year": 2016 }, { "abstract": "OBJECTIVE To explore the genetic basis for a fetus featuring growth restriction and validate the effectiveness of a novel noninvasive prenatal testing (NIPT) technique for the detection of chromosomal microdeletions. METHODS Next generation sequencing(NGS) and fluorescence in situ hybridization(FISH) were used to analyze the DNA of the fetus. Conventional G banding was used to analyze the karyotypes of the fetus and its parents. High throughput sequencing was used to analyze free fetal DNA. RESULTS NGS analysis has revealed a 4.88 Mb deletion at 15q11.2 q13.1 region in the fetus, which has a 99% overlap with the critical region of Prader Willi syndrome (Type 2) and Angelman syndrome (Type 2) and encompassed critical genes including SNRPN and UBE3A. NIPT also revealed a 4.6 Mb deletion at 15q12, which was consistent with the results of fetal cord blood and amniotic DNA testing. FISH assay has confirmed the result of NGS. By karyotying, all subjects showed a normal karyotypes at a level of 320~400 bands. CONCLUSION It is quite necessary to carry out genetic testing on fetuses showing growth restriction. NIPT for fetal chromosomal microdeletions/microduplication syndromes is highly accurate for the diagnosis of Prader Willi/Angelman syndrome.", "author_names": [ "Ming Gao", "Hong Pang", "Yulin Shi", "Xiaojing Feng", "Yanhui Zhao", "Jun Hua", "Dan Tong", "Jinping Liu", "Juan Wen", "Tingting Fan", "Lingqian Wu" ], "corpus_id": 145822614, "doc_id": "145822614", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "[Genetic diagnosis and non invasive prenatal testing of a fetus with Prader Willi/Angelman syndrome]", "venue": "Zhonghua yi xue yi chuan xue za zhi Zhonghua yixue yichuanxue zazhi Chinese journal of medical genetics", "year": 2019 }, { "abstract": "Fetuses of women with alloantibodies to RhD (D) are at risk from hemolytic disease of the fetus and newborn, but only if the fetal red cells are D positive. In such pregnancies, it is beneficial to determine fetal D type, as this will affect the management of the pregnancy. It is possible to predict, with a high level of accuracy, fetal blood group phenotypes from genotyping tests on fetal DNA. The best source is the small quantity of fetal DNA in the blood of pregnant women, as this avoids the requirement for invasive procedures of amniocentesis or chorionic villus sampling (CVS) Many laboratories worldwide now provide noninvasive fetal D genotyping as a routine service for alloimmunized women, and some also test for c, E, C and K.", "author_names": [ "Geoff L Daniels", "Kirstin M Finning", "Pete Martin", "Edwin J Massey" ], "corpus_id": 34039684, "doc_id": "34039684", "n_citations": 152, "n_key_citations": 7, "score": 0, "title": "Noninvasive prenatal diagnosis of fetal blood group phenotypes: current practice and future prospects", "venue": "Prenatal diagnosis", "year": 2009 } ]

[ { "abstract": "Exciton polariton condensates have attractive features for quantum computation, e.g. room temperature operation, high dynamical speed, ease of probe, and existing fabrication techniques. Here, we present a complete theoretical scheme of quantum computing with exciton polariton condensates formed in semiconductor micropillars. Quantum fluctuations on top of the condensates are shown to realize qubits, which are externally controllable by applied laser pulses. Quantum tunneling and nonlinear interactions between the condensates allow SWAP, square root SWAP and controlled NOT gate operations between the qubits.", "author_names": [ "Sanjib Ghosh", "Timothy C H Liew" ], "corpus_id": 214371289, "doc_id": "214371289", "n_citations": 19, "n_key_citations": 0, "score": 1, "title": "Quantum computing with exciton polariton condensates", "venue": "", "year": 2020 }, { "abstract": "Josephson junctions are the basis for the most sensitive magnetic flux detectors, the definition of the unit volt by the Josephson voltage standard, and superconducting digital and quantum computing. They result from the coupling of two coherent quantum states, as they occur in superconductors, superfluids, atomic Bose Einstein condensates, and exciton polariton condensates. In their ground state, Josephson junctions are characterised by an intrinsic phase jump. Controlling this phase jump is fundamental for applications in computing. Here, we experimentally demonstrate controllable phase relations between photon Bose Einstein condensates resulting from particle exchange in a thermo optically tunable potential landscape. Our experiment realises an optical analogue of a controllable 0,\\pi$ Josephson junction. By connecting several junctions, we can study a reconfigurable 4 condensate system demonstrating the potential of our approach for analog spin glass simulation. More generally, the combination of static and dynamic nanostructuring techniques introduced in our work offers a powerful platform for the implementation of adaptive optical systems for paraxial light in and outside of thermal equilibrium.", "author_names": [ "Mario Vretenar", "Ben Kassenberg", "Shivan Bissesar", "Chris Toebes", "Jan Klaers" ], "corpus_id": 210920035, "doc_id": "210920035", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Controllable Josephson junction for photon Bose Einstein condensates", "venue": "Physical Review Research", "year": 2021 }, { "abstract": "Quantum gases of atoms and exciton polaritons are now well established theoretical and experimental tools for fundamental studies of quantum many body physics and suggest promising applications to quantum computing. Given their technological complexity, it is of paramount interest to devise other systems where such quantum many body physics can be investigated at lesser technological expense. Here we examine a relatively well known system of laser light propagating through thermo optical defocusing media: based on a hydrodynamic description of light as a quantum fluid of interacting photons, we investigate such systems as a valid room temperature alternative to atomic or exciton polariton condensates for studies of many body physics. First, we show that by using a technique traditionally used in oceanography it is possible to perform a direct measurement of the single particle part of the dispersion relation of the elementary excitations on top of the photon fluid and to detect its global flow. Then, using a pump and probe setup, we investigate the dispersion of excitation modes of the fluid: for very long wavelengths, a sonic, dispersionless propagation is observed that we interpret as a signature of superfluid behavior.", "author_names": [ "David Vocke", "Thomas Roger", "Francesco Marino", "Ewan M Wright", "Iacopo Carusotto", "Matteo Clerici", "Daniele Faccio" ], "corpus_id": 54916689, "doc_id": "54916689", "n_citations": 50, "n_key_citations": 2, "score": 0, "title": "Experimental characterization of nonlocal photon fluids", "venue": "", "year": 2014 }, { "abstract": "Quantum gases of atoms and exciton polaritons are nowadays a well established theoretical and experimental tool for fundamental studies of quantum many body physics and suggest promising applications to quantum computing. Given their technological complexity, it is of paramount interest to devise other systems where such quantum many body physics can be investigated at a lesser technological expense. Here we examine a relatively well known system of laser light propagating through thermo optical defocusing media: based on a hydrodynamical description of light as a quantum fluid of interacting photons, we investigate such systems as a valid, room temperature alternative to atomic or exciton polariton condensates for studies of many body physics. First, we show that by using a technique traditionally used in oceanography, it is possible to perform a direct measurement of the single particle part of the dispersion relation of the elementary excitations on top of the photon fluid and to detect its global flow. Then, using a pump and probe set up, we investigate the collective nature of low wavevector sound modes of the fluid and observe signatures of superfluid behaviour.", "author_names": [ "David Vocke", "Thomas Roger", "Francesco Marino", "Ewan M Wright", "Iacopo Carusotto", "Matteo Clerici", "Daniele Faccio" ], "corpus_id": 118845469, "doc_id": "118845469", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Experimental characterisation of nonlocal photon superfluids", "venue": "", "year": 2015 }, { "abstract": "We investigate theoretically the quantum oscillator like states recently observed experimentally in polariton condensates. We consider a complex Gross Pitaevskii type model that includes the effects of self interactions, and creation and decay of exciton polaritons. We develop a perturbation theory for approximate solutions to this non equilibrium condensate model and compare the results with numerically calculated solutions for both repulsive and attractive polariton polariton interactions. While the nonlinearity has a weak effect on the mode selection, the condensate density profiles are modified at moderate gain strengths. We find the nonlinearity becomes more dominant when a very large gain of polaritons leads to an extended cloud with high condensate densities. Finally, we identify the relation of the observed patterns to the input pump configuration, and suggest this may serve as a generalized NOR gate in the tradition of optical computing.", "author_names": [ "Florian Pinsker", "Tristram J Alexander" ], "corpus_id": 119256938, "doc_id": "119256938", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Nonlinear eigenmodes of a non equilibrium harmonic oscillator", "venue": "Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences", "year": 2015 }, { "abstract": "Recently, the two dimensional nanocavity exciton polariton system confined in semiconductor nanocavities has emerged as a promising alternative of BoseEinstein Condensate (BEC) The strong quantum correlations presents in this system, make it an unique candidate for studying entanglement and quantum phase transitions qualitative changes in the ground state properties In this work, we review previous evidence, obtained by us, in the phase transitions of a finite exciton polariton system. First, by using a BCS wave function to compute the ground state energy of N excitons without the photonic field, a crossover from the high density electron hole phase to the BCS excitonic phase is found, at a density which is roughly four times the close packing density of excitons. Second, by means of a self consistent procedure with a trial function composed of a coherent photon field and a BCS function for the electron hole pairs, we obtain the scaling of the critical temperature with the number of polaritons. Using the method proposed originally by Olliver and Zurek, and subsequently developed by Bo Li and Zhi Xi Wang we calculate the discord for a generalized density operator, proposed by Blaizot", "author_names": [ "G Guirales", "Boris A Rodriguez", "Herbert Vinck Posada" ], "corpus_id": 125459140, "doc_id": "125459140", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "BETWEEN QUANTUM CORRELATIONS AND PHASE TRANSITIONS IN AN EXCITON POLARITON BEC CONFINED IN A NANOCAVITY", "venue": "", "year": 2013 }, { "abstract": "Coupling matter excitations to electromagnetic modes inside nano scale optical resonators leads to the formation of hybrid light matter states, so called polaritons, allowing the controlled manipulation of material properties. Here, we investigate the photo induced dynamics of a prototypical strongly coupled molecular exciton microcavity system using broadband two dimensional Fourier transform spectroscopy and unravel the mechanistic details of its ultrafast photo induced dynamics. We find evidence for a direct energy relaxation pathway from the upper to the lower polariton state that initially bypasses the excitonic manifold of states, which is often assumed to act as an intermediate energy reservoir, under certain experimental conditions. This observation provides new insight into polariton photophysics and could potentially aid the development of applications that rely on controlling the energy relaxation mechanism, such as in solar energy harvesting, manipulating chemical reactivity, the creation of Bose Einstein condensates and quantum computing. Recent spectroscopic studies have elucidated light matter interactions in exciton polaritons at room temperature, yet their precise excited state dynamics remain unclear. Here, broadband 2D Fourier transform spectroscopy reveals the relaxation between polaritonic states and the role of dark states.", "author_names": [ "Lars Mewes", "Mao Wang", "Rebecca A Ingle", "Karl Borjesson", "Majed Chergui" ], "corpus_id": 221616927, "doc_id": "221616927", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Energy relaxation pathways between light matter states revealed by coherent two dimensional spectroscopy", "venue": "", "year": 2020 }, { "abstract": "The universal critical behavior of the driven dissipative non equilibrium Bose Einstein condensation transition is investigated employing the field theoretical renormalization group method. Such criticality may be realized in broad ranges of driven open systems on the interface of quantum optics and many body physics, from exciton polariton condensates to cold atomic gases. The starting point is a noisy and dissipative Gross Pitaevski equation corresponding to a complex valued Landau Ginzburg functional, which captures the near critical non equilibrium dynamics, and generalizes Model A for classical relaxational dynamics with non conserved order parameter. We confirm and further develop the physical picture previously established by means of a functional renormalization group study of this system. Complementing this earlier numerical analysis, we analytically compute the static and dynamical critical exponents at the condensation transition to lowest non trivial order in the dimensional epsilon expansion about the upper critical dimension d_c 4, and establish the emergence of a novel universal scaling exponent associated with the non equilibrium drive. We also discuss the corresponding situation for a conserved order parameter field, i.e. (sub )diffusive Model B with complex coefficients.", "author_names": [ "Uwe Claus Tauber", "Sebastian Diehl" ], "corpus_id": 108289044, "doc_id": "108289044", "n_citations": 33, "n_key_citations": 1, "score": 0, "title": "Perturbative Field Theoretical Renormalization Group Approach to Driven Dissipative Bose Einstein Criticality", "venue": "", "year": 2013 }, { "abstract": "The two main predictions of quantum field theory in curved space time, namely Hawking radiation and cosmological pair production, have not been directly tested and involve ultra high energy configurations. As a consequence, they should be considered with caution. Using the analogy with condensed matter systems put forward by Unruh, their analogue versions could be tested in the lab. Moreover, the high energy behavior of these systems is known and involved dispersion and dissipation, which regulate the theory at short distances. When considering experiments which aim to test the above predictions, the thermal noise will contaminate the outcome. Indeed, there will be a competition between the stimulated emission from thermal noise and the spontaneous emission out of vacuum. In order to measure the quantum analogue Hawking radiation, or the analogue pair production also called dynamical Casimir effect, one should thus compute the consequences of ultraviolet dispersion and dissipation, and identify observables able to establish that the spontaneous emission took place. In this thesis, we first analyze the effects of dispersion and dissipation on both Hawking radiation and pair particle production. To get explicit results, we work in the context of de Sitter space. Using the extended symmetries of the theory in such a background, exact results are obtained. These are then transposed to the context of black holes using the correspondence between de Sitter space and the black hole near horizon region. To introduce dissipation, we consider an exactly solvable model producing any decay rate. In such a model, the field is linearly coupled to an environment containing a dense set of degrees of freedom. We also study the quantum entanglement of the particles so produced. In a second part, we consider explicit condensed matter systems, namely Bose Einstein condensates and exciton polariton systems. We analyze the effects of dissipation on entanglement produced by the dynamical Casimir effect. As a final step, we study the entanglement of Hawking radiation in the presence of dispersion for a generic analogue system.", "author_names": [ "Xavier Busch" ], "corpus_id": 118397631, "doc_id": "118397631", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Dispersive and dissipative effects in quantum field theory in curved space time to modelize condensed matter systems", "venue": "", "year": 2014 }, { "abstract": "We consider theoretically nonlinear effects in a semiconductor quantum well embedded inside a photonic microcavity. Two photon absorption by a 2p exciton state is considered and investigated; the matrix element of two photon absorption is calculated. We compute the emission spectrum of the sample and demonstrate that under coherent pumping the nonlinearity of the two photon absorption process gives rise to bistability. (c) 2013 Optical Society of America OCIS codes: (190.1450) Bistability; (190.4180) Multiphoton processes. References and links 1. J. 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Lagoudakis, \"Nonlinear optical spin Hall effect and long range spin transport in polariton lasers,\" Phys. Rev. Lett. 109(3) 036404 (2012) 18. S. Christopoulos, G. Baldassarri Hoger von Hogersthal, A. Grundy, P. G. Lagoudakis, A. V. Kavokin, J. J. Baumberg, G. Christmann, R. Butte, E. Feltin, J. F. Carlin, and N. Grandjean, \"Room temperature polariton lasing in semiconductor microcavities,\" Phys. Rev. Lett. 98(12) 126405 (2007) 19. Ayan Das, Junseok Heo, Marc Jankowski, Wei Guo, Lei Zhang, Hui Deng, and Pallab Bhattacharya, \"Room temperature ultralow threshold GaN nanowire polariton laser,\" Phys. Rev. Lett. 107(6) 066405 (2011) 20. R. Schmidt Grund, B. Rheinlnder, C. Czekalla, G. Benndorf, H. Hochmut, A. Rahm, M. Lorenz, and M. Grundmann,\"ZnO based planar and micropillar resonators,\" Superlattic. Microstruct. 41(5 6) 360 363 (2007) 21. S. Kena Cohen and S. R. Forrest, \"Room temperature polariton lasing in an organic single crystal microcavity,\" Nature Photonics 4, 371 375 (2010) 22. T. C. H. Liew, I. A. Shelykh, and G. Malpuech, \"Polaritonic devices,\" Physica E 43(9) 1543 1568 (2011) 23. K. V. Kavokin, M. A. Kaliteevski, R. A. Abram, A. V. Kavokin, S. Sharkova, and I. A. Shelykh, \"Stimulated emission of terahertz radiation by exciton polariton lasers,\" Appl. Phys. Lett. 97(20) 201111 (2010) 24. A. V. Kavokin, I. A. Shelykh, T. Taylor, and M. M. Glazov, \"Vertical cavity surface emitting terahertz laser,\" Phys. Rev. Lett. 108(19) 197401 (2012) 25. C. Weisbuch, M. Nishioka, A. Ishikawa, and Y. Arakawa,\"Observation of the coupled exciton photon mode splitting in a semiconductor quantum microcavity,\" Phys. Rev. Lett. 69(23) 3314 3317 (1992) 26. I. G. Savenko, O. V. Kibis, and I. A. Shelykh, \"Asymmetric quantum dot in a microcavity as a nonlinear optical element,\" Phys. Rev. A 85(5) 053818 (2012) 27. A. V. Kavokin, J. J. Baumberg, G. Malpuech, and F. P. Laussy, Microcavities (Oxford University, (2007) 28. V. D. Kulakovskii, A. I. Tartakovskii, D. N. Krizhanovskii, A. Armitage, J. S. Roberts, and M. S. Skolnick, \"Two dimensional excitonic polaritons and their interaction,\" Phys. Usp. 43(8) 853 857 (2000) 29. N. A. Gippius, S. G. Tikhodeev, V. D. Kulakovskii, D. N. Krizhanovskii, and A. I. Tartakovskii, \"Nonlinear dynamics of polariton scattering in semiconductor microcavity: Bistability vs. stimulated scattering,\" Europhys. Lett. 67(6) 997 (2004) 30. D. M. Whittaker, \"Effects of polariton energy renormalization in the microcavity optical parametric oscillator,\" Phys. Rev. B 71(11) 115301 (2005) 31. A. Baas, J. P. Karr, M. Romanelli, A. Bramati, and E. Giacobino, \"Optical bistability in semiconductor microcavities in the nondegenerate parametric oscillation regime: Analogy with the optical parametric oscillator,\" Phys. Rev. B 70(16) 161307(R) (2004) 32. N. A. Gippius, I. A. Shelykh, D. D. Solnyshkov, S. S. Gavrilov, Yuri G. Rubo, A. V. Kavokin, S. G. Tikhodeev, and G. Malpuech, \"Polarization multistability of cavity polaritons,\" Phys. Rev. Lett. 98(23) 236401 (2007) 33. T. K. Paraiso, M. Wouters, Y. Leger, F. Morier Genoud, and B. Deveaud Pledran, \"Multistability of a coherent spin ensemble in a semiconductor microcavity,\" Nature Mater. 9, 655 660 (2010) 34. D. Bajoni, E. Semenova, A. Lematre, S. Bouchoule, E. Wertz, P. Senellart, S. Barbay, R. Kuszelewicz, and J. Bloch, \"Optical bistability in a GaAs based polariton diode,\" Phys. Rev. Lett. 101(26) 266402 (2008) 35. T. C. H. Liew, A. V. Kavokin, and I. A. Shelykh, \"Optical circuits based on polariton neurons in semiconductor microcavities,\" Phys. Rev. Lett. 100(11) 116401 (2008) 36. A. Amo, T. H. C. Liew, C. Adrados, R. Houdre, E. Giacobino, A. V. Kavokin, and A. Bramati, \"Exciton polariton spin switches,\" Nature Photon. 4, 361 366 (2010) 37. D. Sarkar, S. S. Gavrilov, M. Sich, J. H. Quilter, R. A. Bradley, N. A. Gippius, K. Guda, V. D. Kulakovskii, M. S. Skolnick, and D. N. Krizhanovskii, \"Polarization bistability and resultant spin rings in semiconductor microcavities,\" Phys. Rev. Lett. 105(21) 216402 (2010) 38. C. Adrados, A. Amo, T. C. H. Liew, R. Hivet, R. Houdr, E. Giacobino, A. V. Kavokin, and A. Bramati, \"Spin rings in bistable planar semiconductor microcavities,\" Phys. Rev. Lett. 105(21) 216403 (2010) 39. T. C. H. Liew, A. V. Kavokin, and I. A. Shelykh, \"Optical circuits based on polariton neurons in semiconductor microcavities,\" Phys. Rev. Lett. 101(1) 016402 (2008) 40. T. C. H. Liew, A. V. Kavokin, T. Ostatnicky, M. Kaliteevski, I. A. Shelykh, and R. A. Abram, \"Exciton polariton integrated circuits,\" Phys. Rev. B 82(3) 033302 (2010) #188332 $15.00 USD Received 8 Apr 2013; revised 25 May 2013; accepted 27 May 2013; published 18 Jun 2013 (C) 2013 OSA 1 July 2013 Vol. 21, No. 13 DOI:10.1364/OE.21.015183 OPTICS EXPRESS 15184 41. I. G. Savenko, I. A. Shelykh, and M. A. Kaliteevski, \"Nonlinear terahertz emission in semiconductor microcavities,\" Phys. Rev. Lett. 107(2) 027401 (2011) 42. F. Tassone and Y. Yamamoto, \"Exciton exciton scattering dynamics in a semiconductor microcavity and stimulated scattering into polaritons,\" Phys. Rev. B 59(16) 10830 10842 (1999) 43. I. A. Shelykh, A. V. Kavokin, Yuri G. Rubo, T. C. H. Liew, and G. Malpuech, \"Polariton polarization sensitive phenomena in planar semiconductor microcavities\" Semicond. Sci. Technol. 25(1) 013001 (2010) 44. A. Verger, C. Ciuti, and I. Carusotto, \"Polariton quantum blockade in a photonic dot,\" Phys. Rev. B 73(19) 193306 (2006) 45. B. C. Jacobs, T. B. Pittman, and J. D. Franson, \"Generation of entangl", "author_names": [ "A A Pervishko", "Timothy C H Liew", "V M Kovalev", "I G Savenko", "Ivan Andreevich Shelykh" ], "corpus_id": 3869420, "doc_id": "3869420", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Nonlinear effects in multiphoton polaritonics", "venue": "", "year": 2013 } ]

[ { "abstract": "Abstract This article reviews recent advances utilizing field ion microscopy (FIM) to extract atomic scale three dimensional images of materials. This capability is not new, as the first atomic scale reconstructions of features utilizing FIM were demonstrated decades ago. The rise of atom probe tomography, and the application of this latter technique in place of FIM has unfortunately severely limited further FIM development. Currently, the ubiquitous availability of extensive computing power makes it possible to treat and reconstruct FIM data digitally and this development allows the image sequences obtained utilizing FIM to be extremely valuable for many material science and engineering applications. This article demonstrates different applications of these capabilities, focusing on its use in physical metallurgy and semiconductor science and technology.", "author_names": [ "Francois Vurpillot", "Frederic Danoix", "Matthieu Gilbert", "Sebastian Koelling", "Michal Dagan", "David N Seidman" ], "corpus_id": 20936300, "doc_id": "20936300", "n_citations": 13, "n_key_citations": 0, "score": 1, "title": "True Atomic Scale Imaging in Three Dimensions: A Review of the Rebirth of Field Ion Microscopy", "venue": "Microscopy and Microanalysis", "year": 2017 }, { "abstract": "Abstract An automated procedure has been developed for the reconstruction of field ion microscopy (FIM) data that maintains its atomistic nature. FIM characterizes individual atoms on the specimen's surface, evolving subject to field evaporation, in a series of two dimensional (2D) images. Its unique spatial resolution enables direct imaging of crystal defects as small as single vacancies. To fully exploit FIM's potential, automated analysis tools are required. The reconstruction algorithm developed here relies on minimal assumptions and is sensitive to atomic coordinates of all imaged atoms. It tracks the atoms across a sequence of images, allocating each to its respective crystallographic plane. The result is a highly accurate 3D lattice resolved reconstruction. The procedure is applied to over 2000 tungsten atoms, including ion implanted planes. The approach is further adapted to analyze carbides in a steel matrix, demonstrating its applicability to a range of materials. A vast amount of information is collected during the experiment that can underpin advanced analyses such as automated detection of \"out of sequence\" events, subangstrom surface displacements and defects effects on neighboring atoms. These analyses have the potential to reveal new insights into the field evaporation process and contribute to improving accuracy and scope of 3D FIM and atom probe characterization.", "author_names": [ "Michal Dagan", "Baptiste Gault", "George D W Smith", "Paul A J Bagot", "Michael P Moody" ], "corpus_id": 3453980, "doc_id": "3453980", "n_citations": 15, "n_key_citations": 1, "score": 1, "title": "Automated Atom By Atom Three Dimensional (3D) Reconstruction of Field Ion Microscopy Data", "venue": "Microscopy and Microanalysis", "year": 2017 }, { "abstract": "Radiation damage in tungsten and a tungsten tantalum alloy, both of relevance to nuclear fusion research, has been characterized using a combination of field ion microscopy (FIM) imaging and atom probe tomography (APT) While APT provides 3D analytical imaging with sub nanometer resolution, FIM is capable of imaging the arrangements of single atoms on a crystal lattice and has the potential to provide insights into radiation induced crystal damage, all the way down to its smallest manifestation a single vacancy. This paper demonstrates the strength of combining these characterization techniques. In ion implanted tungsten, it was found that atomic scale lattice damage is best imaged using FIM. In certain cases, APT reveals an identifiable imprint in the data via the segregation of solute and impurities and trajectory aberrations. In a W 5at%Ta alloy, a combined APT FIM study was able to determine the atomic distribution of tantalum inside the tungsten matrix. An indirect method was implemented to identify tantalum atoms inside the tungsten matrix in FIM images. By tracing irregularities in the evaporation sequence of atoms imaged with FIM, this method enables the benefit of FIM's atomic resolution in chemical distinction between the two species.", "author_names": [ "Michal Dagan", "Luke R Hanna", "Alan Xu", "Stephen Roberts", "George D W Smith", "Baptiste Gault", "Philip D Edmondson", "Paul A J Bagot", "Michael P Moody" ], "corpus_id": 23529765, "doc_id": "23529765", "n_citations": 18, "n_key_citations": 2, "score": 0, "title": "Imaging of radiation damage using complementary field ion microscopy and atom probe tomography.", "venue": "Ultramicroscopy", "year": 2015 }, { "abstract": "Alan Cottrell was among the first to recognize the potential of field ion microscopy for the atomic scale study of crystal defects. The study of atomic configurations at the core of dislocations by this method proved to be unexpectedly difficult, because of the mechanical stresses imposed on the specimen by the high electric field. The development of atom probe tomography revitalized such studies. In particular, the atom probe technique permitted the first direct observations of solute atom distributions in the region of dislocations and confirmed the existence of so called 'Cottrell Atmospheres' which are of great importance in the understanding of phenomena such as strain ageing. Atom probe studies of dislocation solute interactions in a diverse range of alloy systems are outlined.", "author_names": [ "G D W Smith", "D Hudson", "P D Styman", "Catherine Williams" ], "corpus_id": 97140070, "doc_id": "97140070", "n_citations": 34, "n_key_citations": 0, "score": 0, "title": "Studies of dislocations by field ion microscopy and atom probe tomography", "venue": "", "year": 2013 }, { "abstract": "The field ion microscope (FIM) can be used to characterize the atomic configuration of the apices of sharp tips. These tips are well suited for scanning probe microscope (SPM) use since they predetermine the SPM resolution and the electronic structure for spectroscopy. A protocol is proposed for preserving the atomic structure of the tip apex from etching due to gas impurities during the period of transfer from the FIM to the SPM, and estimations are made regarding the time limitations of such an experiment due to contamination with ultra high vacuum rest gases. While avoiding any current setpoint overshoot to preserve the tip integrity, we present results from approaches of atomically defined tungsten tips to the tunneling regime with Au(111) HOPG (highly oriented pyrolytic graphite) and Si(111) surfaces at room temperature. We conclude from these experiments that adatom mobility and physisorbed gas on the sample surface limit the choice of surfaces for which the tip integrity is preserved in tunneling experiments at room temperature. The atomic structure of FIM tip apices is unchanged only after tunneling to the highly reactive Si(111) surface.", "author_names": [ "W Palmberg Paul", "Yoichi Miyahara", "Peter Grutter" ], "corpus_id": 20590090, "doc_id": "20590090", "n_citations": 19, "n_key_citations": 2, "score": 0, "title": "Implementation of atomically defined field ion microscopy tips in scanning probe microscopy.", "venue": "Nanotechnology", "year": 2012 }, { "abstract": "We perform detailed numerical simulations of field ion microscopy images of faceted crystals and compare them with experimental observations. In contrast to the case of crystals with a smooth surface, for a faceted topography we find extreme deformations of the ion image. Local magnification is highly inhomogeneous and may vary by an order of magnitude: from 0.64 to 6.7. Moreover, the anisotropy of the magnification at a point located on the facet edge may reach a factor of 10.", "author_names": [ "Daniel Niewieczerzal", "Czeslaw Oleksy", "Andrzej Szczepkowicz" ], "corpus_id": 5268814, "doc_id": "5268814", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Image deformation in field ion microscopy of faceted crystals.", "venue": "Ultramicroscopy", "year": 2010 }, { "abstract": "Field ion microscopic imaging of monatomic carbon chains near the ground quantum states and the visualization of their two dimensional wave functions were demonstrated. Quantum motions with the frequency proportional to the electric field are detected and analyzed with subangstrom lateral resolution. Electric fields above 10(10) V/m can be used for control of a transverse vibration mode of atomic chains in the terahertz spectral range.", "author_names": [ "Tatjana I Mazilova", "Igor M Mikhailovskij", "V A Ksenofontov", "Evgenij Sadanov" ], "corpus_id": 29762272, "doc_id": "29762272", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Field ion microscopy of quantum oscillations of linear carbon atomic chains.", "venue": "Nano letters", "year": 2009 }, { "abstract": "1. Historical background and general introduction 2. Physical principles of field ion microscopy 3. FIM image interpretation and application 4. Physical principles of atom probe interpretation 5. Statistical analysis of atom probe data 6. Metallurgical applications 7. Atom probe studies of non metallic materials, thin films and surface phenomena Epilogue: future directions", "author_names": [ "Michael K Miller" ], "corpus_id": 98003248, "doc_id": "98003248", "n_citations": 757, "n_key_citations": 28, "score": 0, "title": "Atom Probe Field Ion Microscopy", "venue": "", "year": 1996 }, { "abstract": "The Helium Ion Microscope (HIM) has the capability to image small features with a resolution down to 0.35 nm due to its highly focused gas field ionization source and its small beam sample interaction volume. In this work, the focused helium ion beam of a HIM is utilized to create nanopores with diameters down to 1.3 nm. It will be demonstrated that nanopores can be milled into silicon nitride, carbon nanomembranes (CNMs) and graphene with well defined aspect ratio. To image and characterize the produced nanopores, helium ion microscopy and high resolution scanning transmission electron microscopy were used. The analysis of the nanopore's growth behavior, allows inferring on the profile of the helium ion beam.", "author_names": [ "Daniel Emmrich", "Andreas Beyer", "Achim Nadzeyka", "Sven Bauerdick", "J C Meyer", "Jani Kotakoski", "Armin Golzhauser" ], "corpus_id": 118974727, "doc_id": "118974727", "n_citations": 61, "n_key_citations": 0, "score": 0, "title": "Nanopore fabrication and characterization by helium ion microscopy", "venue": "", "year": 2016 }, { "abstract": "On October 11, 1955, Muller and Bahadur Pennsylvania State University observed individual tungsten atoms on the surface of a sharply pointed tungsten tip by cooling it to 78 K and employing helium as the imaging gas. Muller and Bahadur were the first persons to observe directly individual atoms, using a field ion microscope FIM which Muller had invented in 1951. This historic and seminal event occurred long before the observations of individual atoms by Z contrast scanning transmission electron microscopy STEM high resolution electron microscopy HREM scanning tunneling microscopy STM or atomic force microscopy AFM A FIM is a lensless point projection microscope that resolves individual atoms on the surface of a sharply pointed tip at magnifications of greater than 106 times. The radius of a tip is 50 nm and is maintained at a positive potential Vdc with respect to earth. Atomic resolution FIM images are achieved by cooling a tip into the range of 20 100 K in a high to ultrahigh vacuum system and placing it at Vdc to generate electric fields E that are between 15 and 60 V nm 1. Helium or neon gas, or a mixture of He and Ne gases, is used to image individual atoms utilizing the phenomenon of field ionization. In these large E fields He or Ne atoms are field ionized, 45 Vdc nm 1 for He and 35 Vdc nm 1 for Ne, above individual surface atoms. This is because the outermost electron of the imaging gas atoms quantum mechanically tunnels into a sharply pointed microtip at the site of an atom. This creates a small diameter cone of He+ or Ne+ ions emanating from individual surface atoms; the total current from a tip with an area of 10 14 m2 is 10 9 10 8 A, hence the current from a single atom is 10 14 10 13 A, respectively. The field ionized He+ or Ne+ ions are then accelerated along E field lines that are orthogonal to the equipotentials associated with a tip and they terminate on a detector, which is at earth potential. The energetic ions are ultimately converted into visible light employing a microchannel plate MCP which is the solidstate analog of an array of photomultiplier tubes, with a gain of 106 107 for a single ion. The detection efficiency of a MCP is equal to its open area, 50% 60% which is a weak link in the detection system and needs to be improved in the future. In the FIM mode of operation, about 104 105 surface atoms are imaged and the FIM images often exhibit the symmetry of the crystal lattice of the specimen. Thus, the physical basis of \"seeing\" atoms in direct space involves the quantum mechanical process of field ionization of imaging gas atoms, which was first analyzed by Oppenheimer 1928 5 for a hydrogen atom in free space in a potential gradient of 102 Vdc m 1; he calculated the time to ionize an atom at this value of E to be 10100 s, which is a googol, whereas in a FIM the time for field ionization is 10 10 s. The E field ionized He+ or Ne+ gas ions are the messengers that allow us to observe individual atoms on the surface of a sharply pointed specimen in direct space with excellent atomic resolution, which is a singular intellectual and scientific achievement with tremendous ramifications for solving important scientific and technological problems in materials research. Subsequently in 1956, Muller discovered the important physical phenomenon of field evaporation or field desorption which is the sublimation of atoms as ions from a microtip radius 40 nm specimen employing a high E field that may be greater or less than the E field necessary to ionize a helium or neon atom at a given cryogenic temperature. Muller observed this phenomenon occurring by increasing the dc voltage on a tungsten specimen, and concomitantly increasing the value of E, and noticing that the atoms at the surface of a microtip are continuously \"evaporating subliming \" as ions, thereby exposing the interior of a specimen, and hence the term field desorption or field evaporation. Field evaporation is sublimation with the aid of an electric field and is a material dependent property; for example, for W the evaporation field Ee is 57 V nm 1, while for Ag, Ee is 25 V nm 1 at 0 K. Field evaporation is controlled by superimposing high voltage pulses Vpulse on top of Vdc, where the pulse fraction Vpulse /Vdc is typically between 0.1 and 0.2; the optimum value is found empirically. In this manner the internal atomic structure of a specimen is routinely observed directly and reconstructed in threedimensions 3D to reveal imperfections: that is, atomicscale defects, such as vacancies, self interstitial atoms, chemical impurity atoms, dislocations, stacking faults, sub boundaries, grain boundaries, clusters of atoms, precipitates, etc. A historic and seminal short course and workshop on FIM was held at the University of Florida in March 14 22, 1966. Review and original articles were presented on both the theory and application of FIM to problems in materials REVIEW OF SCIENTIFIC INSTRUMENTS 78, 030901 2007", "author_names": [ "David N Seidman" ], "corpus_id": 45718945, "doc_id": "45718945", "n_citations": 31, "n_key_citations": 1, "score": 0, "title": "Perspective: From field ion microscopy of single atoms to atom probe tomography: A journey: \"Atom probe tomography\" [Rev. Sci. Instrum. 78, 031101 (2007)", "venue": "The Review of scientific instruments", "year": 2007 } ]

[ { "abstract": "Low cost semiconductor photocatalysts offer unique possibilities for industrial chemical transformations and energy conversion applications. We report that a range of organic semiconductors are capable of efficient photocatalytic oxygen reduction to H2O2 in aqueous conditions. These semiconductors, in the form of thin films, support a 2 electron/2 proton redox cycle involving photoreduction of dissolved O2 to H2O2, with the concurrent photooxidation of organic substrates: formate, oxalate, and phenol. Photochemical oxygen reduction is observed in a pH range from 2 to 12. In cases where valence band energy of the semiconductor is energetically high, autoxidation competes with oxidation of the donors, and thus turnover numbers are low. Materials with deeper valence band energies afford higher stability and also oxidation of H2O to O2. We found increased H2O2 evolution rate for surfactant stabilized nanoparticles versus planar thin films. These results evidence that photochemical O2 reduction may be a widespread feature of organic semiconductors, and open potential avenues for organic semiconductors for catalytic applications.", "author_names": [ "Maciej Gryszel", "Mykhailo Sytnyk", "Marie Jakesova", "Giuseppe Romanazzi", "Roger Gabrielsson", "Wolfgang Heiss", "Eric Daniel Glowacki" ], "corpus_id": 206481697, "doc_id": "206481697", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "General Observation of Photocatalytic Oxygen Reduction to Hydrogen Peroxide by Organic Semiconductor Thin Films and Colloidal Crystals.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "Oxygenic photosynthesis gave rise to a regulatory mechanism based on reversible redox modifications of enzymes. In chloroplasts, such on off switches separate metabolic pathways to avoid futile cycles. During illumination, the redox interconversions allow for rapidly and finely adjusting activation states of redox regulated enzymes. Noncovalent effects by metabolites binding to these enzymes, here addressed as 'small molecules' affect the rates of reduction and oxidation. The chloroplast enzymes provide an example for a versatile regulatory principle where small molecules govern thiol switches to integrate redox state and metabolism for an appropriate response to environmental challenges. In general, this principle can be transferred to reactive thiols involved in redox signaling, oxidative stress responses, and in disease of all organisms.", "author_names": [ "Johannes Knuesting", "Renate Scheibe" ], "corpus_id": 52100594, "doc_id": "52100594", "n_citations": 21, "n_key_citations": 1, "score": 1, "title": "Small Molecules Govern Thiol Redox Switches.", "venue": "Trends in plant science", "year": 2018 }, { "abstract": "Abstract Iron redox transformations by five representative Sulfolobus strains (S. metallicus Kra23, S. tokodaii 7, S. acidocaldarius 98 3, S. solfataricus P1, S. shibatae B12) were studied to clarify the general trend of Fe metabolism across different species of the genus Sulfolobus. Negligible to major Fe(II) oxidation was detected in cell suspensions of the strains. Fe(III) reducing ability was differently expressed in each strain with dependence on the oxygen level and growth status; growth uncoupled cell suspensions of all strains reduced Fe(III) under either anaerobic or microaerobic conditions, or under both conditions. A linear correlation between cell growth and Fe(III) reduction was also found in S. tokodaii 7, S. solfataricus P1, and S. shibatae B12. In addition to Fe redox behaviors, the strains were also tested for reduction of highly toxic Cr(VI) to less toxic and soluble Cr(III) as an application possibility; the trend in degree of Cr(V) reduction did not necessarily correspond to that of Fe(III) reduction, suggesting the involvement of different reduction mechanisms.", "author_names": [ "Yusei Masaki", "Katsutoshi Tsutsumi", "Naoko Okibe" ], "corpus_id": 90556283, "doc_id": "90556283", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Iron Redox Transformation by the Thermo Acidophilic Archaea from the Genus Sulfolobus", "venue": "", "year": 2018 }, { "abstract": "Abstract Cross coupling reactions catalyzed by transition metals are among the most influential in modern synthetic chemistry. The vast majority of transition metal catalyzed cross couplings rely on a catalytic cycle involving alternating oxidation and reduction of the metal center and are generally limited to forging just one type of new bond per reaction (e.g. the biaryl linkage formed during a Suzuki cross coupling) This work presents an Isohypsic Redox Sequence (IRS) that uses one metal to effect two catalytic cycles, thereby generating multiple new types of bonds from a single catalyst source. We show that the IRS strategy is amenable to several widely used transformations including the Suzuki Miyaura coupling, Buchwald Hartwig amination, and Wacker oxidation. Furthermore, each of these reactions generates value added heterocycles with significant sp3 C (3 dimensional) content. Our results provide a general framework for generating complex products by using a single metal to fulfill multiple roles. By uniting different combinations of reactions in the isohypsic and redox phases of the process, this type of catalytic multiple bond forming platform has the potential for wide applicability in the efficient synthesis of functional organic molecules.", "author_names": [ "Craig D Smith", "David E Phillips", "Alina Tirla", "David J France" ], "corpus_id": 52182103, "doc_id": "52182103", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Catalytic Isohypsic Redox Sequences for the Rapid Generation of Csp3 Containing Heterocycles", "venue": "Chemistry", "year": 2018 }, { "abstract": "A new redox active, diarylamido based ligand (LN3P2) capable of k5 N,N,N,P,P chelation has been used to prepare a series of complexes with the general formula [MII(LN3P2)]X, where M Fe (1; X OTf) Co (2; X ClO4) or Ni (3; X ClO4) The diarylamido core of monoanionic LN3P2 is derived from bis(2 amino 4 methylphenyl)amine, which undergoes condensation with two equivalents of 2 (diphenylphosphanyl)benzaldehyde to provide chelating arms with both arylphosphine and imine donors. X ray structural, magnetic, and spectroscopic studies indicate that the N3P2 coordination environment generally promotes low spin configurations. Three quasi reversible redox couples between +1.0 and 1.5 V (vs. Fc+/Fc) were observed in voltammetric studies of each complex, corresponding to MII/MIIIoxidation, LN3P2 based oxidation, and MII/MI reduction (in order of highest to lowest potential) Spectroscopic and computational analyses of 3ox generated via chemical one electron oxidation of 3 revealed that a stable diarylaminyl radical (LN3P2* is formed upon oxidation. The ability of the CoII complex (2) to function as an electrocatalyst for H2generation was evaluated in the presence of weak acids. Moderate activity was observed using 4 tert butylphenol as the proton source at potentials below 2.0 V. The insights gained here will assist in the future design of pentadentate mixed N/P based chelates for catalytic processes.", "author_names": [ "Denan Wang", "Danushka M Ekanayake", "Sergey V Lindeman", "Claudio N Verani", "Adam T Fiedler" ], "corpus_id": 105767556, "doc_id": "105767556", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Multielectron Redox Chemistry of Transition Metal Complexes Supported by a Non Innocent N3P2 Ligand: Synthesis, Characterization, and Catalytic Properties", "venue": "", "year": 2018 }, { "abstract": "In this report, we identify the relevant factors to increase production of medium chain n alcohols through an expanded view of the reverse b oxidation pathway. We began by creating a base strain capable of producing medium chain n alcohols from glucose using a redox balanced and growth coupled metabolic engineering strategy. By dividing the heterologous enzymes in the pathway into different modules, we were able to identify and evaluate homologs of each enzyme within the pathway and identify several capable of enhancing medium chain alcohol titers and/or selectivity. In general, the identity of the trans 2 enoyl CoA reductase (TER) and the direct overexpression of the thiolase (FadA) and b hydroxy acyl CoA reductase (FadB) improved alcohol titer and the identity of the FadBA complex influenced the dominant chain length. Next, we linked the anaerobically induced VHb promoter from Vitreoscilla hemoglobin to each gene to remove the need for chemical inducers and ensure robust expression. The highest performing strain with the autoinduced reverse b oxidation pathway produced n alcohols at titers of 1.8 g/L with an apparent molar yield of 0.2 on glucose consumed in rich medium (52% of theoretical yield)", "author_names": [ "Christopher R Mehrer", "Matthew R Incha", "Mark C Politz", "Brian F Pfleger" ], "corpus_id": 44110850, "doc_id": "44110850", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Anaerobic production of medium chain fatty alcohols via a b reduction pathway.", "venue": "Metabolic engineering", "year": 2018 }, { "abstract": "Oxidation and reduction cycles are used in the regeneration of nanoparticle catalysts that have deactivated due to sintering or poisoning. Nickel oxidation and reduction cycles for the redispersion of nickel nanoparticles were studied via in situ high angle annular dark field environmental scanning transmission electron microscopy. Cycling the Ni/NiO system through successive redox cycles shows that the particles retain the same general size distributions even though Ostwald ripening and particle migration and coalescence is occurring. The regeneration of the smallest nanoparticle sizes, which disappear due to sintering processes, occur by the ejection of small (2 3 nm) nickel particles during the reduction of the hollow nickel oxide nanostructures. The nickel nanoparticles above ~3.5 nm in size form hollow polycrystalline nickel oxide nanostructures upon oxidation. Upon reduction, the grains making up the shell of the hollow nickel oxide reduce separately at the grains surface and at the grain boundaries.", "author_names": [ "Alec P LaGrow", "David C Lloyd", "Pratibha L Gai", "Edward D Boyes" ], "corpus_id": 103575308, "doc_id": "103575308", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "In Situ Scanning Transmission Electron Microscopy of Ni Nanoparticle Redispersion via the Reduction of Hollow NiO", "venue": "", "year": 2018 }, { "abstract": "Our society's current energy demands are largely met by the exploitation of fossil fuels, which are unsustainable and environmentally harmful resources. However, Nature has provided us with a clean and virtually limitless alternative in the form of solar energy. This abundant resource is utilized constantly by photosynthetic organisms, which has in turn motivated decades of research in our quest to create artificial counterparts of comparable scales. In this feature article, we will highlight some of the recent novel approaches in the field of artificial photosynthesis (AP) which we define by a more general term as a process that stores energy overall by generating fuels and chemicals using light. We will particularly emphasize on the potential of a highly modular plug and play concept that we hope will persuade the community to explore a more inclusive variety of multielectron redox catalysis to complement the proton reduction and water oxidation half reactions in traditional solar water splitting systems. We discuss some of the latest developments in the vital functions of light harvesting, charge separation, and multielectron reductive and oxidative catalysis, as well as their optimization, to achieve the ultimate goal of storing sunlight in chemical bonds. Specific attention is dedicated to the use of earth abundant elements and molecular catalysts that offer greater product selectivity and more intricate control over the reactivity than heterogeneous systems. In this context, we showcase our team's contributions in presenting a unique oxidative carbon carbon bond cleavage reaction in aliphatic alcohols and biomass model compounds, under ambient atmospheric conditions, facilitated by vanadium photocatalysts. We offer this discovery as a promising alternative to water oxidation in an integrated AP system, which would concurrently generate both solar fuels and valuable solar chemicals.", "author_names": [ "Milos Dokic", "Han Sen Soo" ], "corpus_id": 206121962, "doc_id": "206121962", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Artificial photosynthesis by light absorption, charge separation, and multielectron catalysis.", "venue": "Chemical communications", "year": 2018 }, { "abstract": "An extensive study of the electrochemical and spectroelectrochemical properties of 14 boron subphthalocyanine (BsubPc) derivatives with various axial and peripheral substituents was performed in 1,2 dichloromethane (CH2Cl2) containing 0.1 M tetra n butyl ammonium perchlorate (TBAP) as the supporting electrolyte. From the cyclic voltammetry results, all compounds exhibit one oxidation and at least two reduction processes within the solvent potential window of +1.6 to 1.8 V vs SCE. It was found that the reversibility of the redox reactions depends on the axial and peripheral substituents and the dipole moment of the boron to axial substituent. In general, UV vis absorption spectra of the singly reduced BsubPc derivatives exhibit three equal intensity peaks in the 450 to 650 nm region that are derived from the maximum BsubPc absorbance peak upon reduction. Axial substituents affect the intensity of the three peaks upon reduction, while peripheral substituents shift the position of the peaks to higher wavelengths. Upon oxidation, the UV vis absorption profile flattens considerably with only a single broad ~300 nm) band apparent. Understanding the effect of substituents on the stability of the redox processes of BsubPcs will aid in further development of these materials for applications in organic electronic devices.", "author_names": [ "Kathleen L Sampson", "Xiaoqin Jiang", "Esmeralda Bukuroshi", "Aleksa Dovijarski", "Hasan Raboui", "Timothy P Bender", "Karl M Kasdish" ], "corpus_id": 4971822, "doc_id": "4971822", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "A Comprehensive Scope of Peripheral and Axial Substituent Effect on the Spectroelectrochemistry of Boron Subphthalocyanines.", "venue": "The journal of physical chemistry. A", "year": 2018 }, { "abstract": "Homoleptic platinum azo iminate complexes are formed when triarylformazans are treated with Pt(DMSO)2Cl2 under reducing conditions. The transformation represents a three proton, three electron reduction of each formazan and offers a new route for accessing this class of redox active ligands. The reaction is general for triarylformazans with both electron donating and electron withdrawing substituents, and four complexes in total are described. X ray crystal structures of all four complexes are presented and are consistent with an electronic structure consisting of a formal Pt(II) center, where each azo iminate is in a monoanionic radical form and contributes five p electrons. The complexes are all diamagnetic, indicating delocalization of the p system over both ligands. The complexes are further characterized by cyclic voltammetry, which shows multiple ligand centered redox events, including proton coupled oxidation waves. UV vis spectroelectrochemistry provides further insight into the nature of the redox events. UV vis absorption spectroscopy shows strong visible absorption bands attributed to HOMO LUMO transitions, which is corroborated by time dependent DFT computations on representative examples.", "author_names": [ "Ge Mu", "Lei Cong", "Zhili Wen", "Judy I-Chia Wu", "Karl M Kadish", "Thomas S Teets" ], "corpus_id": 51718315, "doc_id": "51718315", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Homoleptic Platinum Azo iminate Complexes via Hydrogenative Cleavage of Formazans.", "venue": "Inorganic chemistry", "year": 2018 } ]

[ { "abstract": "This article analyzes the existing methods of increasing reliability through multiple overstatement of the installed power of electric equipment according to the criterion of minimum total yearly costs. The proposed method of optimization of power circuits of semiconductor converters includes stages of choosing the configuration of power circuits on the basis of the limit of semiconductor switches and choosing the optimal number of phases and redundant units. The distinguishing characteristic of the method is the criterion used, namely, the probability of failure free operation. This new method reduces the cost of installed power of a semiconductor converter compared to the known synthetic method on the level of total annual costs. It is shown that this method has some degree of flexibility; e.g. the development of the element base can be considered on the basis of the corresponding coefficients that depend on the operating temperature of power semiconductor valves. The proposed method can be successfully used in the design of semiconductor converters for supplying powerful electric drives, where, in the general case, the number of phases of a power circuit is not three. In this case, multiphase windings of an electric machine are connected according to a scheme with potential phase separation, which can be considered as an equivalent multiple redundancy system.", "author_names": [ "Artyom A Gryzlov", "M A Grigor'ev", "Azaliya A Imanova" ], "corpus_id": 116209905, "doc_id": "116209905", "n_citations": 61, "n_key_citations": 2, "score": 1, "title": "Improving the reliability of semiconductor converters for supplying electric drives of exhausters", "venue": "", "year": 2017 }, { "abstract": "This paper deals with increasing the reliability of electric drives of exhausters of the oxygen converter process. The dependences of the reliability parameters in the electrical converter electric motor system on the power reserve were obtained. The costs for the installed equipment were taken as an optimization criterion. It is noted that improving the reliability of an electric drive is possible both by increasing the overall power of the power unit and by changing the number of phases. It is shown that the reliability of the system can be improved in a synchronous electric drive with pulse vector control at the reservation of a semiconductor converter. A mathematical model of the electrical converter reluctance motor with a field regulated machine complex is proposed. The results of the mathematical modeling of the synchronous electric drive with pulse vector control are considered. The dependence of the specific electric parameters on the number of phases is determined.", "author_names": [ "M A Grigor'ev", "Dmitry Sychev", "Artyom M Zhuravlev", "Evgeny S Khayatov", "Nikita V Savosteenko" ], "corpus_id": 113213051, "doc_id": "113213051", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "Improving the reliability of electric drives of exhausters of the oxygen converter process", "venue": "", "year": 2015 }, { "abstract": "With ever increasing concerns on our environment, there is a fast growing interest in electric vehicles (EVs) and hybrid EVs (HEVs) from automakers, governments, and customers. As electric drives are the core of both EVs and HEVs, it is a pressing need for researchers to develop advanced electric drive systems. In this paper, an overview of permanent magnet (PM) brushless (BL) drives for EVs and HEVs is presented, with emphasis on machine topologies, drive operations, and control strategies. Then, three major research directions of the PM BL drive systems are elaborated, namely, the magnetic geared outer rotor PM BL drive system, the PM BL integrated starter generator system, and the PM BL electric variable transmission system.", "author_names": [ "Kwok Tong Chau", "Ching Chuen Chan", "Chunhua Liu" ], "corpus_id": 12098072, "doc_id": "12098072", "n_citations": 1091, "n_key_citations": 31, "score": 0, "title": "Overview of Permanent Magnet Brushless Drives for Electric and Hybrid Electric Vehicles", "venue": "IEEE Transactions on Industrial Electronics", "year": 2008 }, { "abstract": "This paper presents a technology review of voltage source converter topologies for industrial medium voltage drives. In this highly active area, different converter topologies and circuits have found their application in the market. This paper covers the high power voltage source inverter and the most used multilevel inverter topologies, including the neutral point clamped, cascaded H bridge, and flying capacitor converters. This paper presents the operating principle of each topology and a review of the most relevant modulation methods, focused mainly on those used by industry. In addition, the latest advances and future trends of the technology are discussed. It is concluded that the topology and modulation method selection are closely related to each particular application, leaving a space on the market for all the different solutions, depending on their unique features and limitations like power or voltage level, dynamic performance, reliability, costs, and other technical specifications.", "author_names": [ "Jose R Rodriguez", "Steffen Bernet", "Bin Wu", "Jorge Pontt", "Samir Kouro" ], "corpus_id": 113863, "doc_id": "113863", "n_citations": 2101, "n_key_citations": 67, "score": 0, "title": "Multilevel Voltage Source Converter Topologies for Industrial Medium Voltage Drives", "venue": "IEEE Transactions on Industrial Electronics", "year": 2007 }, { "abstract": "With the requirements for reducing emissions and improving fuel economy, automotive companies are developing electric, hybrid electric, and plug in hybrid electric vehicles. Power electronics is an enabling technology for the development of these environmentally friendlier vehicles and implementing the advanced electrical architectures to meet the demands for increased electric loads. In this paper, a brief review of the current trends and future vehicle strategies and the function of power electronic subsystems are described. The requirements of power electronic components and electric motor drives for the successful development of these vehicles are also presented.", "author_names": [ "Ali Emadi", "Young-Joo Lee", "Kaushik Rajashekara" ], "corpus_id": 20821804, "doc_id": "20821804", "n_citations": 1082, "n_key_citations": 32, "score": 0, "title": "Power Electronics and Motor Drives in Electric, Hybrid Electric, and Plug In Hybrid Electric Vehicles", "venue": "IEEE Transactions on Industrial Electronics", "year": 2008 }, { "abstract": "This paper reviews the relative merits of induction, switched reluctance, and permanent magnet (PM) brushless machines and drives for application in electric, hybrid, and fuel cell vehicles, with particular emphasis on PM brushless machines. The basic operational characteristics and design requirements, viz. a high torque/power density, high efficiency over a wide operating range, and a high maximum speed capability, as well as the latest developments, are described. Permanent magnet brushless dc and ac machines and drives are compared in terms of their constant torque and constant power capabilities, and various PM machine topologies and their performance are reviewed. Finally, methods for enhancing the PM excitation torque and reluctance torque components and, thereby, improving the torque and power capability, are described", "author_names": [ "Zi Qiang Zhu", "David Howe" ], "corpus_id": 33707412, "doc_id": "33707412", "n_citations": 1053, "n_key_citations": 30, "score": 0, "title": "Electrical Machines and Drives for Electric, Hybrid, and Fuel Cell Vehicles", "venue": "Proceedings of the IEEE", "year": 2007 }, { "abstract": "Hybrid electric vehicle (HEV) technology provides an effective solution for achieving higher fuel economy, better performance, and lower emissions, compared with conventional vehicles. Plug in HEVs (PHEVs) are HEVs with plug in capabilities and provide a more all electric range; hence, PHEVs improve fuel economy and reduce emissions even more. PHEVs have a battery pack of high energy density and can run solely on electric power for a given range. The battery pack can be recharged by a neighborhood outlet. In this paper, a novel integrated bidirectional AC/DC charger and DC/DC converter (henceforth, the integrated converter) for PHEVs and hybrid/plug in hybrid conversions is proposed. The integrated converter is able to function as an AC/DC battery charger and to transfer electrical energy between the battery pack and the high voltage bus of the electric traction system. It is shown that the integrated converter has a reduced number of high current inductors and current transducers and has provided fault current tolerance in PHEV conversion.", "author_names": [ "Young-Joo Lee", "Alireza Khaligh", "Ali Emadi" ], "corpus_id": 29078144, "doc_id": "29078144", "n_citations": 394, "n_key_citations": 18, "score": 0, "title": "Advanced Integrated Bidirectional AC/DC and DC/DC Converter for Plug In Hybrid Electric Vehicles", "venue": "IEEE Transactions on Vehicular Technology", "year": 2009 }, { "abstract": "This work is devoted to review and analyze the most relevant characteristics of multilevel converters, to motivate possible solutions, and to show that we are in a decisive instant in which energy companies have to bet on these converters as a good solution compared with classic two level converters. This article presents a brief overview of the actual applications of multilevel converters and provides an introduction of the modeling techniques and the most common modulation strategies. It also addresses the operational and technological issues.", "author_names": [ "Leopoldo Garcia Franquelo", "J Rodriguez", "Jose Ignacio Leon", "Samir Kouro", "Ramon C Portillo", "M Angeles Martin Prats" ], "corpus_id": 31488309, "doc_id": "31488309", "n_citations": 1684, "n_key_citations": 65, "score": 0, "title": "The age of multilevel converters arrives", "venue": "IEEE Industrial Electronics Magazine", "year": 2008 }, { "abstract": "Multilevel converters are considered today as the state of the art power conversion systems for high power and power quality demanding applications. This paper presents a tutorial on this technology, covering the operating principle and the different power circuit topologies, modulation methods, technical issues and industry applications. Special attention is given to established technology already found in industry with more in depth and self contained information, while recent advances and state of the art contributions are addressed with useful references. This paper serves as an introduction to the subject for the not familiarized reader, as well as an update or reference for academics and practicing engineers working in the field of industrial and power electronics.", "author_names": [ "Jose R Rodriguez", "Leopoldo Garcia Franquelo", "Samir Kouro", "Jose Ignacio Leon", "Ramon C Portillo", "M Angeles Martin Prats", "Marcelo A Perez" ], "corpus_id": 30722327, "doc_id": "30722327", "n_citations": 954, "n_key_citations": 50, "score": 0, "title": "Multilevel Converters: An Enabling Technology for High Power Applications", "venue": "Proceedings of the IEEE", "year": 2009 }, { "abstract": "Introduction. Generating Capacity Basic Probability Methods. Generating Capacity Frequency and Duration Method. Interconnected Systems. Operating Reserve. Composite Generation and Transmission Systems. Distribution Systems Basic Techniques and Radial Networks. Distribution Systems Parallel and Meshed Networks. Distribution Systems Extended Techniques. Substations and Switching Stations. Plant and Station Availability. Applications of Monte Carlo Simulation. Evaluation of Reliability Worth. Epilogue. Appendix 1: Definitions. Appendix 2: Analysis of the IEEE Reliability Test System. Appendix 3: Thirdorder Equations for Overlapping Events. Solutions to Problems. Index.", "author_names": [ "Roy Billinton", "Ronald N Allan" ], "corpus_id": 203948762, "doc_id": "203948762", "n_citations": 3312, "n_key_citations": 388, "score": 0, "title": "Reliability evaluation of power systems", "venue": "", "year": 1984 } ]

[ { "abstract": "Ionic liquids are room temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer electrolyte membrane fuel cells) fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.", "author_names": [ "Michel Armand", "Frank Endres", "Douglas R Macfarlane", "Hiroyuki Ohno", "Bruno Scrosati" ], "corpus_id": 19813330, "doc_id": "19813330", "n_citations": 3509, "n_key_citations": 20, "score": 1, "title": "Ionic liquid materials for the electrochemical challenges of the future.", "venue": "Nature materials", "year": 2009 }, { "abstract": "Applications of ionic liquids at electrified interfaces to energy storage systems, electrowetting devices, or nanojunction gating media cannot proceed without a deep understanding of the structure and properties of the interfacial double layer. This article provides a detailed critique of the present work on this problem. It promotes the point of view that future considerations of ionic liquids should be based on the modern statistical mechanics of dense Coulomb systems, or density functional theory, rather than classical electrochemical theories which hinge on a dilute solution approximation. The article will, however, contain more questions than answers. To trigger the discussion, it starts with a simplified original result. A new analytical formula is derived to rationalize the potential dependence of double layer capacitance at a planar metal ionic liquid interface. The theory behind it has a mean field character, based on the Poisson Boltzmann lattice gas model, with a modification to account for the finite volume occupied by ions. When the volume of liquid excluded by the ions is taken to be zero (that is, if ions are extremely sparsely packed in the liquid) the expression reduces to the nonlinear Gouy Chapman law, the canonical result typically used to describe the potential dependence of capacitance in electrochemical double layers. If ionic volume exclusion takes more realistic values, the formula shows that capacitance potential curves for an ionic liquid may differ dramatically from the Gouy Chapman law. Capacitance has a maximum close to the potential of zero charge, rather than the familiar minimum. At large potenials, capacitance decreases with the square root of potential, rather than increases exponentially. The reported formula does not take into account the specific adsorption of ions, which, if present, can complicate the analysis of experimental data. Since electrochemists use to think about the capacitance data in terms of the classical Gouy Chapman theory, which, as we know, should be good only for electrolytes of moderate concentration, the question of which result is \"better\" arises. Experimental data are sparse, but a quick look at them suggests that the new formula seems to be closer to reality. Opinions here could, however, split. Indeed, a comparison with Monte Carlo simulations has shown that incorporation of restricted volume effects in the mean field theory of electrolyte solutions may give results that are worse than the simple Gouy Chapman theory. Generally, should the simple mean field theory work for such highly concentrated ionic systems, where the so called ion correlation effects must be strong? It may not, as it does not incorporate a possibility of charge density oscillations. Somehow, to answer this question definitely, one should do further work. This could be based on density functional theory (and possibly not on what is referred to as local density approximation but rather \"weighted density approximation\" field theory methods for the account of fluctuations in the calculation of partition function, heuristic integral equation theory extended to the nonlinear response, systematic force field computer simulations, and, most importantly, experiments with independently determined potentials of zero charge, as discussed in the paper.", "author_names": [ "Alexei A Kornyshev" ], "corpus_id": 40709383, "doc_id": "40709383", "n_citations": 852, "n_key_citations": 25, "score": 0, "title": "Double layer in ionic liquids: paradigm change?", "venue": "The journal of physical chemistry. B", "year": 2007 }, { "abstract": "We combine old, unpublished data on ionic liquids containing quaternary ammonium cations with new data on salts of aromatic cations containing a variety of anions, to demonstrate the existence for ionic liquids of an unexpectedly wide range of liquid fragilities. The pattern is one now familiar for other liquids. Here, the pattern is important in determining the relative fluid properties at ambient temperatures. We find that the optimization of ionic liquids for ambient temperature applications requiring low vapor pressure fluid phases involves the proper interplay of both cohesive energy and fragility factors. The cohesive energy is discussed in terms of the coulomb and van der Waals contributions to the attractive part of the pair potential. On the basis of the relation between the glass transition temperature and the molar volume for salts with less polarizable anions, we find evidence for a broad minimum in the ionic liquid cohesive energy at an internuclear separation of ca. 0.6 nm. This minimum lies.", "author_names": [ "Wu Xu", "Emanuel I Cooper", "C Austen Angell" ], "corpus_id": 95642834, "doc_id": "95642834", "n_citations": 760, "n_key_citations": 4, "score": 0, "title": "Ionic liquids: Ion mobilities, glass temperatures, and fragilities", "venue": "", "year": 2003 }, { "abstract": "Small and salty CO2 reduction scheme Most artificial photosynthesis approaches focus on making hydrogen. Modifying CO2, as plants and microbes do, is more chemically complex. Asadi et al. report that fashioning WSe2 and related electrochemical catalysts into nanometer scale flakes greatly improves their activity for the reduction of CO2 to CO. An ionic liquid reaction medium further enhances efficiency. An artificial leaf with WSe2 reduced CO2 on one side while a cobalt catalyst oxidized water on the other side. Science, this issue p. 467 Nanostructuring tungsten diselenide enhances catalytic activity for carbon dioxide conversion to carbon monoxide in an ionic liquid medium. Conversion of carbon dioxide (CO2) into fuels is an attractive solution to many energy and environmental challenges. However, the chemical inertness of CO2 renders many electrochemical and photochemical conversion processes inefficient. We report a transition metal dichalcogenide nanoarchitecture for catalytic electrochemical CO2 conversion to carbon monoxide (CO) in an ionic liquid. We found that tungsten diselenide nanoflakes show a current density of 18.95 milliamperes per square centimeter, CO faradaic efficiency of 24% and CO formation turnover frequency of 0.28 per second at a low overpotential of 54 millivolts. We also applied this catalyst in a light harvesting artificial leaf platform that concurrently oxidized water in the absence of any external potential.", "author_names": [ "Mohammad Asadi", "Kibum Kim", "Cong Liu", "Aditya Venkata Addepalli", "Pedram Abbasi", "Poya Yasaei", "Patrick J Phillips", "Amirhossein Behranginia", "Jose M Cerrato", "Richard T Haasch", "Peter Zapol", "Bijandra Kumar", "Robert F Klie", "J T Abiade", "Larry A Curtiss", "Amin Salehi-Khojin" ], "corpus_id": 538567, "doc_id": "538567", "n_citations": 489, "n_key_citations": 0, "score": 0, "title": "Nanostructured transition metal dichalcogenide electrocatalysts for CO2 reduction in ionic liquid", "venue": "Science", "year": 2016 }, { "abstract": "We review recent works on the synthesis and application of poly(ionic liquid)s (PILs) Novel chemical structures, different synthetic strategies and controllable morphologies are introduced as a supplement to PIL systems already reported. The primary properties determining applications, such as ionic conductivity, aqueous solubility, thermodynamic stability and electrochemical/chemical durability, are discussed. Furthermore, the near term applications of PILs in multiple fields, such as their use in electrochemical energy materials, stimuli responsive materials, carbon materials, and antimicrobial materials, in catalysis, in sensors, in absorption and in separation materials, as well as several special interest applications, are described in detail. We also discuss the limitations of PIL applications, efforts to improve PIL physics, and likely future developments.", "author_names": [ "Wenjing Qian", "John Texter", "Feng Yan" ], "corpus_id": 3641478, "doc_id": "3641478", "n_citations": 407, "n_key_citations": 1, "score": 0, "title": "Frontiers in poly(ionic liquid)s: syntheses and applications.", "venue": "Chemical Society reviews", "year": 2017 }, { "abstract": "This Review covers the recent developments (2005 2015) in the design, synthesis, characterization, and application of thermotropic ionic liquid crystals. It was designed to give a comprehensive overview of the \"state of the art\" in the field. The discussion is focused on low molar mass and dendrimeric thermotropic ionic mesogens, as well as selected metal containing compounds (metallomesogens) but some references to polymeric and/or lyotropic ionic liquid crystals and particularly to ionic liquids will also be provided. Although zwitterionic and mesoionic mesogens are also treated to some extent, emphasis will be directed toward liquid crystalline materials consisting of organic cations and organic/inorganic anions that are not covalently bound but interact via electrostatic and other noncovalent interactions.", "author_names": [ "Karel Goossens", "Kathleen Lava", "Christopher W Bielawski", "Koen Binnemans" ], "corpus_id": 206898987, "doc_id": "206898987", "n_citations": 355, "n_key_citations": 2, "score": 0, "title": "Ionic Liquid Crystals: Versatile Materials.", "venue": "Chemical reviews", "year": 2016 }, { "abstract": "Ionic liquid gel materials offer a way to further utilise ionic liquids in technological applications. Combining the controlled and directed assembly of gels, with the diverse applications of ionic liquids, enables the design of a heady combination of functional tailored materials, leading to the development of task specific/functional ionic liquid gels. This review introduces gels and gel classification, focusing on ionic liquid gels and their potential roles in a more sustainable future. Ionic liquid gels provide the ability to build functionality at every level, the solid component, the ionic liquid, and any incorporated active functional agents. This allows materials to be custom designed for a vast assortment of applications. This diverse class of materials has the potential to yield functional materials for green and sustainable chemistry, energy, electronics, medicine, food, cosmetics, and more. The discussion of the development of ionic liquid gel materials for applications in green and sustainable chemistry centres on uses of ionic liquid gels in catalysis and energy.", "author_names": [ "Patricia C Marr", "Andrew Craig Marr" ], "corpus_id": 98111350, "doc_id": "98111350", "n_citations": 233, "n_key_citations": 2, "score": 0, "title": "Ionic liquid gel materials: applications in green and sustainable chemistry", "venue": "", "year": 2016 }, { "abstract": "The IR and Raman spectra and conformations of the ionic liquid 1 ethyl 3 methyl 1H imidazolium tetrafluoroborate, [EMIM][BF4] (6) were analyzed within the framework of scaled quantum mechanics (SQM) It was shown that SQM successfully reproduced the spectra of the ionic liquid. The computations revealed that normal modes of the EMIM+ BF4 ion pair closely resemble those of the isolated ions EMIM+ and BF4 except for the antisymmetric BF stretching vibrations of the anion, and the out of plane and stretching vibrations of the H C(2) moiety of the cation. The most plausible explanation for the pronounced changes of the latter vibrations upon ion pair formation is the H bonding between H C(2) and BF4 However, these weak H bonds are of minor importance compared with the Coulomb interactions between the ions that keep them closely associated even in dilute CD2Cl2 Solutions. According to the 'gas phase' computations, in these associates, the BF4 anion is positioned over the imidazolium ring of the EMIM+ cation and has short contacts not only with the H C(2) of the latter, but also with a proton of the Me N(3) group.", "author_names": [ "Sergey A Katsyuba", "Paul J Dyson", "Elena E Vandyukova", "Alla V Chernova", "Ana Vidis" ], "corpus_id": 94399606, "doc_id": "94399606", "n_citations": 157, "n_key_citations": 0, "score": 0, "title": "Molecular Structure, Vibrational Spectra, and Hydrogen Bonding of the Ionic Liquid 1 Ethyl 3 methyl 1H imidazolium Tetrafluoroborate", "venue": "", "year": 2004 }, { "abstract": "We calculate the heats of vaporisation for imidazolium based ionic liquids [C(n)mim][NTf(2) with n=1, 2, 4, 6, 8 by means of molecular dynamics (MD) simulations and discuss their behavior with respect to temperature and the alkyl chain length. We use a force field developed recently. The different cohesive energies contributing to the overall heats of vaporisations are discussed in detail. With increasing alkyl chain length, the Coulomb contribution to the heat of vaporisation remains constant at around 80 kJ mol( 1) whereas the van der Waals interaction increases continuously. The calculated increase of about 4.7 kJ mol( 1) per CH(2) group of the van der Waals contribution in the ionic liquid exactly coincides with the increase in the heats of vaporisation for n alcohols and n alkanes, respectively. The results support the importance of van der Waals interactions even in systems completely composed of ions.", "author_names": [ "Thorsten Koddermann", "Dietmar Paschek", "Ralf Ludwig" ], "corpus_id": 39233875, "doc_id": "39233875", "n_citations": 96, "n_key_citations": 0, "score": 0, "title": "Ionic liquids: dissecting the enthalpies of vaporization.", "venue": "Chemphyschem a European journal of chemical physics and physical chemistry", "year": 2008 }, { "abstract": "Precise coexistence curves are reported for the liquid liquid phase transition of binary solutions of the room temperature ionic liquid (RTIL) 1 methyl 3 hexylimidazolium tetrafluoroborate (C6mim+BF4 in a series of alcohols (1 butanol, 1 pentanol, 2 butanol, and 2 pentanol) The phase diagrams are determined by measuring the temperature dependence of the refractive index in the two phases of samples of critical composition. The critical data of the systems are in the region predicted for the model fluid of equal sized, charged, hard spheres in a dielectric continuum, the so called restricted primitive model (RPM) Therefore, the phase transition can be classified as essentially driven by Coulomb interactions. The effective exponents beff determined are close to the universal Ising value, where the deviations are found to be negative, when the volume fraction or the mass fraction are chosen as concentration variable. The negative values of the first Wegner correction indicate non uniform crossover from Ising to mean field criticality. The diameter of the coexistence curves shows the non analytic temperature dependence typical for Ising systems.", "author_names": [ "Monika Wagner", "Olimpiu Stanga", "Wolffram Schrer" ], "corpus_id": 96124610, "doc_id": "96124610", "n_citations": 71, "n_key_citations": 1, "score": 0, "title": "The liquid?liquid coexistence of binary mixtures of the room temperature ionic liquid 1 methyl 3 hexylimidazolium tetrafluoroborate with alcoholsElectronic supplementary information (ESI) available: Temperatures and corresponding refractive index data in the one phase region and in the coexisting ph", "venue": "", "year": 2004 } ]

[ { "abstract": "As motor vehicle exhaust emission causes more and more serious pollution in recent years, the natural environment and human health are facing great threats. It is of great significance to accurately measure the concentration of carbon monoxide, as one of the main pollutants of vehicle exhaust emissions. The detection system based on tunable diode laser absorption spectroscopy (TDLAS) is featured by high resolution, high sensitivity and fast response. Besides, TDLAS can eliminate the interference of the remaining gas by using tunable and narrow linewidth characteristics of semiconductor lasers, and selecting the single absorption line of specific gas, and finally realize the gas concentration inversion of high precision. Based on TDLAS, the motor vehicle exhaust component CO concentration detection system was designed and realized by using DFB laser with the center wavelength of 2330nm and selecting the absorption lines of CO gas at 2333nm. The hardware composition and software design of the system were introduced. In the experiment, motor vehicle exhaust of different vehicles was collected, and spectrum data obtained through the system components were used for CO concentration inversion. To improve the signal to noise ratio of the system and reduce the detection limit of the system, the balance detection technology was used in the system. Experiments show that the system has excellent stability, and can ensure accurate inversion of concentration results, and meet the real time on line detection of vehicle exhaust CO concentration.", "author_names": [ "Yi-bing Lu", "Wenqing Liu", "Yujun Zhang", "Kai Zhang", "Dongqi Yu" ], "corpus_id": 139285634, "doc_id": "139285634", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "The design of motor vehicle exhaust carbon monoxide concentration detection system based on tunable diode laser absorption spectroscopy", "venue": "International Symposium on Advanced Optical Manufacturing and Testing Technologies (AOMATT)", "year": 2019 }, { "abstract": "Abstract A highly sensitive low concentration gas sensor based on dual wavelength Erbium doped fiber ring laser (EDFRL) is designed and demonstrated. The dual wavelength lasing output is introduced by a tunable Fabry Perot (F P) filter and a fiber Bragg grating (FBG) due to the mode competition as they both share a same EDF gain medium. One wavelength at 1530.37 nm serving as the sensing element is inserted by a hollow core photonic crystal fiber (HCPCF) gas cell which can bring in much more power change when the cavity loss slightly varies while the other wavelength at 1532.38 nm acting as a reference. Experimental results show that the sensor can achieve a good linear response (R2 0.9864) to acetylene concentration variation and a minimum detection limit (MDL) of 10.42 ppmV at 20 s response time, which is the lowest to our best knowledge and improving 6.44 times than that of single wavelength EDFRL based. Moreover, the absolute detected error induced by the power fluctuation", "author_names": [ "Xianchao Yang", "Liangcheng Duan", "Haiwei Zhang", "Ying Lu", "Guangyao Wang", "Jianquan Yao" ], "corpus_id": 196993284, "doc_id": "196993284", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "Highly sensitive dual wavelength fiber ring laser sensor for the low concentration gas detection", "venue": "Sensors and Actuators B: Chemical", "year": 2019 }, { "abstract": "Seven common optical methods for gas concentration detection are described. The basic principles, advantages and disadvantages of each method are given in detail. The improvement work and some novel ideas are presented. The applications of combined methods are discussed. These optical methods include some con ventional gas concentration detection technologies, such as optical interferential method, photoacoustic detection (PAS) correlation spectroscopy, and some novel gas concentration detection technologies, such as tunable diode laser absorption spectroscopy (TDLAS) evanescent wave field sensing technology, hollow core photonic bandgap fiber (HC PBF) sensing technology and fiber loop ring down spectroscopy (FLRDS) The prospect of optical gas sensing is listed at the end of the paper, which mainly refers to miniaturization, intelligence, portability, low power consumption, high accuracy, fast response and distributed multi component telemetry technology.", "author_names": [ "Shutao Wang", "Changbing Wang", "Zhao Pan", "Deming Kong", "Qi Cheng", "Zhifang Wang" ], "corpus_id": 139733593, "doc_id": "139733593", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Applications of optical technology in gas concentration detection", "venue": "", "year": 2017 }, { "abstract": "The invention relates to an optic travelling wave cavity enhanced laser raman gas concentration detection device. The device combines a cavity enhanced technology with a laser raman detection technology, and utilizes an optic traveling wave passive cavity; a single curved surface annular internal reflector forms a high fineness cavity, and a laser outgoing beam oblique incidence cavity enhanced principle is utilized, so that laser beam is reflected in the cavity for many times and is propagated in a travelling wave manner, the laser beam passes through gas to be detected in an area to generate raman scattering, raman scattered light is collected by a photoelectric detection component after being gathered with the laser beam through a filter plate, and the photoelectric detection component detects the raman frequency shift and the corresponding raman peak intensity of the characteristics of the gas to be detected to obtain the concentration of the gas to be detected. The detection device disclosed by the invention has the characteristics of simple structure, low requirements on mechanical location, good stability and high reliability; meanwhile, the anti jamming performance of the detection device is improved; the detection device can measure on line in real time to increase the dynamic information of the process and can detect the concentration of nearly all gas, except inert gas; the sensitivity is high; the response speed is high and the response time is short.", "author_names": [ "" ], "corpus_id": 140975755, "doc_id": "140975755", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optic travelling wave cavity enhanced laser raman gas concentration detection device", "venue": "", "year": 2014 }, { "abstract": "The relationship between absorption and gas concentration was studied using a diffuse integrating cavity as a gas cell. The light transmission process in an arbitrary diffuse cavity was theoretically derived based on a beam reflection analysis. It was found that a weak absorption condition must be satisfied to ensure a linear relationship between absorbance and gas concentration. When the weak absorption condition is not satisfied, a non linear relation will be observed. A 35 x 35 x 35 cm diffuse integrating cavity was used in the experiment. Different oxygen concentrations were measured by detecting the P9 absorption line at 763.8 nm, based on tunable diode laser absorption spectroscopy. The relationship between the absorption signals and oxygen concentration was linear at low oxygen concentrations and became non linear when oxygen concentrations were higher than 21% The absorbance value of this transition point was 0.17, which was considered as the weak absorption condition for this system. This work studied the theoretical reason for the non linear phenomenon and provided an experimental method to determine the transition point when using a diffuse integrating cavity as a gas cell.", "author_names": [ "Xue Zhou", "Jia Yu", "Lin Wang", "Zhiguo Zhang" ], "corpus_id": 89605737, "doc_id": "89605737", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Investigating the Relation between Absorption and Gas Concentration in Gas Detection Using a Diffuse Integrating Cavity", "venue": "", "year": 2018 }, { "abstract": "Online dissolved gas analysis (DGA) is an effective technique to obtain the health status information of insulation oil in power transformers. The typical hydrocarbon gases (methane, ethyne, ethene, ethane) decomposed from insulation oil, are the key indicators to diagnose the fault type and severity. To realize contactless and field measurement, a multi gas detection system based on tunable diode laser absorption spectrum (TDLAS) is proposed in this paper. Critical technique problems on the light source, long path gas cell, and the topology for multi gas detection are investigated. Individual central wavelengths of hydrocarbon gases are set at as 1653.72 nm for methane, 1530.37 nm for ethyne, 1620.04 nm for ethene and 1679.06 nm for ethane in the near infrared band. A 10.13 m long multi pass gas cell is developed with the advantage of anti vibration design. To share the optical absorption path, an optical switch is adopted to merge the multi gas detection system. The high sensitivity of the TDLAS multi gas detection system was demonstrated in the laboratory calibrations, with ethyne detection reaching sub parts per million level, and the other hydrocarbon gases achieving ppm level. Furthermore, the comparison detection in the real 220 kV power transformer gave evidence to the effective monitoring of DGA, proving it an alternative approach to online detection of multiple gases in power transformer oil.", "author_names": [ "Jun Jiang", "Zhuowei Wang", "Xiao Han", "Chaohai Zhang", "Guoming Ma", "Chengrong Li", "Ying-Ting Luo" ], "corpus_id": 59235010, "doc_id": "59235010", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Multi gas detection in power transformer oil based on tunable diode laser absorption spectrum", "venue": "IEEE Transactions on Dielectrics and Electrical Insulation", "year": 2019 }, { "abstract": "Tunable diode laser absorption spectroscopy (TDLAS) is a technique measuring the concentration of trace gas, the gas concentration is in the sub ppm (part per million) range. Experiment results show that the main part of system noise is interference fringes originating from multiple reflections between surfaces in optical components, so called etalon effects. This work investigates the basis principle of the measurement of trace gas concentration using wavelength modulation spectroscopy (WMS) technique and analyses etalon effects from different types of optical surfaces. Fluctuations in temperature or vibrations of the etalon cause the interference fringes to shift in wavelength, and the interference fringes originated from short etalons within laser or photodetector cannot be removed by subtraction of a zero baseline using wedged or dithered components. It is shown that although analytical signal, SAS,nf, for short etalons, is decreasing with increased detection order, the signal to background ratio (SAS/SBG)nf is improved significantly. It is more advantageous to detect higher even harmonic signals, e.g. the 4th or 6th, than 2nd to reduce or eliminate the interference fringes originated from short etalons within laser or photodetector.", "author_names": [ "Jia-nian Cao", "Zhuo Wang", "Ke-ke Zhang", "Rui Yang", "Yong Wang" ], "corpus_id": 32065133, "doc_id": "32065133", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Etalon Effects Analysis in Tunable Diode Laser Absorption Spectroscopy Gas Concentration Detection System Based on Wavelength Modulation Spectroscopy", "venue": "2010 Symposium on Photonics and Optoelectronics", "year": 2010 }, { "abstract": "In order to improve the signal to noise ratio(SNR) and the detection limit of the tunable diode laser absorption spectroscopy(TDLAS) the system's second harmonic signal and noise are analyzed.Then four kinds of digital filtering techniques are used for comparison, and four corresponding software programs written by Visual C+ language are used for noise compression and signal extraction from the original noised second harmonic signal.Finally, the a b g filter and Kalman filter are used for denoising and data smoothing.The results show that the detecting limit is improved from 30 ppm to 5 ppm by introducing least square method and the SNR is enhanced to 8 times by using the Kalman filter.This method is applied to the TDLAS on line industrial gas monitoring system,and a good result can be obtained.", "author_names": [ "Wang Yu" ], "corpus_id": 137942019, "doc_id": "137942019", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Selection of digital filtering techniques in trace gas concentration detection with a tunable diode laser absorption spectroscopy", "venue": "", "year": 2010 }, { "abstract": "Abstract Gas line shape is determined by the Voigt profile, which is the convolution of Lorentz and Doppler profiles. The calculation amount in the Voigt profile is much larger than that in the two other profiles, and an approximate Lorentz or Doppler profile is generally used in gas concentration detection via tunable laser absorption spectroscopy. The normalized peak ratio and error function are introduced to compare the approximating effect of the two profiles. The normalized peak ratio value is simulated for Doppler profile and Lorentz profiles over a variable temperature and pressure, respectively. The 10% 5% and 2.5% error functions for pressure versus temperature are obtained for the two profiles. Oxygen at a wavelength of 760 nm is used to demonstrate the simulation results. The presented method of investigating line shapes can be applied to other gas spectrum lines.", "author_names": [ "Wenke Liang", "Xiaozhou Dong", "Yunfeng Bi", "Tieliang Lv" ], "corpus_id": 125883924, "doc_id": "125883924", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Temperature and pressure dependence of the line shape at l 763 nm in oxygen concentration detection", "venue": "", "year": 2019 }, { "abstract": "The invention discloses a system and method for gas concentration detection based on a programmable amplifier. The system comprises a microprocessor, the microprocessor is connected with a current driving circuit, the current driving circuit is connected with a DFB laser, and the DFB laser is connected with an optical fiber coupler. The optical fiber coupler is used for dividing a light beam emitted by the DFB laser into first beam optical signals and second beam optical signals to respectively send the first beam optical signals and the second beam optical signals to a first photoelectric detector and an air chamber; the first photoelectric detector converts the received first beam optical signals into a reference voltage and then transmits the reference voltage to a first programmable amplifying circuit, the air chamber is connected with a second photoelectric detector, and the second photoelectric detector is used for receiving optical signals output from the air chamber, converting the optical signals into voltage signals and transmitting the voltage signals to a second programmable amplifier. The output end of the first programmable amplifier and the output end of the second programmable amplifier are connected with a first input end and a second input end of a differential circuit, the output end of the differential circuit is connected with the input end of a signal conditioning circuit, and the output end of the signal conditioning circuit is connected with a microprocessor.", "author_names": [ "" ], "corpus_id": 132480759, "doc_id": "132480759", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "System and method for gas concentration detection based on programmable amplifier", "venue": "", "year": 2015 } ]

[ { "abstract": "We experimentally demonstrate efficient broadband self powered photo detection and power generation in thin films of polycrystalline bismuth telluride (Bi2Te3) semiconductors under inhomogeneous strain. The developed simple, junction free, lightweight, and flexible photo detectors are composed of a thin active layer and Ohmic contacts on a flexible plastic substrate, and can operate at room temperature and without application of an external bias voltage. We attribute the observed phenomena to the generation of an electric field due to a spontaneous polarization produced by strain gradient, which can separate both photo generated and thermally generated charge carriers in bulk of the semiconductor material, without a semiconductor junction. We show that the developed photo detectors can generate electric power during both the daytime and the nighttime, by either harnessing solar and thermal radiation or by emitting thermal radiation into the cold sky. To the best of our knowledge, this is the first demonstration of the power generation in a simple junction free device under negative illumination, which exhibits higher voltage than the previously used expensive commercial HgCdTe photo diode. Significant improvements in the photo detector performance are expected if the low charge mobility polycrystalline active layer is replaced with high quality single crystal material. The technology is not limited to Bi2Te3 as the active material, and offers many potential applications in night vision, wearable sensors, long range LIDAR, and daytime/nighttime energy generation technologies.", "author_names": [ "Bruno Lorenzi", "Yoichiro Tsurimaki", "Akihiro Kobayashi", "Masayuki Takashiri", "Svetlana V Boriskina" ], "corpus_id": 222155920, "doc_id": "222155920", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Self powered broadband photo detection and persistent energy generation with junction free strained Bi2Te3 thin films.", "venue": "Optics express", "year": 2020 }, { "abstract": "The interactions between electromagnetic field and the biological system can lead to the change of biological morphology, structure, function and other aspects at the different levels of biological targets. The domestic sewage is secondarily disinfected using continuous electromagnetic waves, the microscopic molecules have a certain dipole moment and the biological molecular aggregates with dielectric properties of the cell may generate dielectric loss under the effect of the applied electromagnetic field. The thermal effect will be produced by putting the microwave energy into the heat of irregular movement which increases biological system's temperature. Under the influence of an applied electromagnetic field, the membrane potentially undergoes conformational changes that would affect K ion, Na ion channels open and make the voltage dependant Ca ion open, the high concentration of Ca ion of the membrane into the cell along the potential gradient, which leads to cell death, resulting in the biological non thermal effects, the greater the changes of cellular transmembrane voltage, the higher the rate of cell death. The experiment results show that the microwave secondary sterilization has a good sterilizing effect, the method has the advantages of high efficiency, low cost, simple operation, easy automation, without adding any substance and does not produce any secondary pollution, etc.", "author_names": [ "" ], "corpus_id": 207820178, "doc_id": "207820178", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "THE EFFECT AND MECHANISM OF URBAN DOMESTIC SEWAGE SECONDARY STERILIZATION BY MICROWAVE", "venue": "", "year": 2019 }, { "abstract": "Non thermal plasma assisted partial oxidation of hydrocarbon fuels (including military logistic fuels) is considered with the intent to rapidly produce hydrogen rich syngas with the least amount of electrical power. The syngas produced can be used to fuel quiet solid oxide fuel cell (SOFC) auxiliary generators, be added to engines or combustors to extend lean operation (decrease NOx and increase efficiency) or be further reformed to increase hydrogen yield (via water gas shift and gas cleanup) for low temperature fuel cells. Unlike catalytic fuel reformers that suffer from adverse issues involving catalyst deactivation (coking and tolerance to sulfur) and require a warmup period dependent on the thermal mass of the catalyst, plasma reforming offers a noncatalytic approach for rapid \"on demand\" hydrogen rich syngas production (quick startup) Plasma fuel reforming is also fuel flexible and can be applied to applications needing dynamic control of a varying amount of syngas such as those having a time dependent load (e.g. engine acceleration/ deceleration) It can also be used to rapidly produced hydrogen for fuel cell powered robots used in place of batteries. In this study, experimental results using a non thermal 'warm' plasma reformer are presented with a focus on the hydrogen and carbon monoxide yields, their selectivities, the efficiency of the reformer and the specific energy density (SED) a measure of the amount of electricity needed to produce a kilogram of hydrogen or syngas. In terms of fuel feedstocks, much of our work to date has focused on plasma reforming of natural gas with recent efforts to extend the work to JP fuels. INTRODUCTION Fuel cells and other applications require hydrogen. In commercial systems, hydrogen is traditionally produced in large scale steam reforming plants and transported to the point of use, which is not practical for most military operations. Instead, fuel reformers are needed to convert jet fuel (a complex blend of heavy hydrocarbons with sulfur impurities) to hydrogen or hydrogen rich syngas at the point of use. A practical approach is to partially oxidize the available fuel to hydrogen rich syngas, which is a mixture of hydrogen and carbon monoxide. For SOFC's, the entire reformate containing mostly hydrogen, carbon dioxide, and small hydrocarbons can potentially be used provided the sulfur levels and aromatic content are sufficiently low. For low temperature protonexchange membrane (PEM) fuel cells, the water Proceedings of the 2018 Ground Vehicle Systems Engineering and Technology Symposium (GVSETS) Rapid Production of Hydrogen Rich Syngas, Pearlman et al. Page 2 of 9 gas shift reaction can be used to convert the carbon monoxide in the reformate to additional hydrogen with the use of steam followed by gas cleanup; the steam can also potentially be recovered from the output of the fuel cell. For partial oxidation, catalytic, thermal, and plasma based approaches exist. Catalytic reforming has been shown to work at least for a limited time [1] yet is sensitive to the high aromatic content and sulfur in the fuel. Also, the catalyst must be initially heated which can slow the startup time depending on its thermal mass. Thermal partial oxidation (TPOX) is also an option, conveniently avoids the need for catalysts, yet does require high reaction temperatures ~1200oC or higher) to achieve high hydrogen concentrations; the high temperatures limit the choice of materials to high temperature metals, metal alloys or ceramics; TPOX reformers also require a startup period dependent on the thermal mass of the reformer. In this work, our focus is on non thermal plasmaassisted partial oxidation. No catalysts are needed and the reformer can rapidly produce hydrogen from a cold start. It is also fuel flexible and sulfur tolerant. It does, however, require electricity to generate a high voltage, low current electric discharge (arc) with which the reactants interact, producing radicals and charged species that promote reforming reactions. Stainless steel electrodes are used in our reformer and can handle typical operating temperatures of 800 1000oC. Also, in our system, the arc discharge continuously translates between two opposed electrodes; this avoids the formation of local hot spots on the electrodes that are undesirable. In effect, by continuously translating the arc discharge, a 'volumetric' discharge is generated that then is used to reform a continuous reactant flow. A key focus of our current work (now funded through the Department of Energy) is also on developing effective ways to lower the electricity needed for plasma assisted fuel reforming; this is important since the cost of electricity is the primary operating cost [4] To do so, our approach has been to efficiently preheat the reactants using heat from the hot reformate exiting the reformer; this raises the temperature of the reactants, which increases the reaction rates resulting in higher syngas yields for the same electrical power. Prior work showing the benefit of preheating is available in references 6 and 7. THERMAL VS. NON THERMAL PLASMA FUEL REFORMING There are two fundamental types of plasmas, thermal and non thermal, both of which have application for fuel reforming. Both plasmas consist of electrons, ionized species and neutral species that promote fuel reforming. For conditions where the all constituents are very energetic (high electron, ion and gas temperatures) the plasma is referred to as a thermal plasma. High electrical power is, however, needed to generate thermal plasmas and is used for bulk heating of the entire gas mixture. With that said, however, thermal plasma fuel reformers are very efficient at producing hydrogen rich syngas from a variety of different hydrocarbon fuels (natural gas, gasoline, diesel, oil, biomass, and jet fuel) have a fast response time, and can be compact (owed to their high power density) [9] In comparison, non thermal plasmas require less electrical power as they do not provide for bulk heating of the gas. Rather, the gas temperatures are comparatively low (neutral and ionized species temperatures are ~300 1,500K) while the electron temperatures are very high (10,000 100,000K) With lower gas temperatures, the need for expensive, high temperature materials is avoided and electrode stability/lifetime is extended. In essence, in non thermal plasmas, high grade electricity is used to create a strong nonequilibrium between the electron temperature and Proceedings of the 2018 Ground Vehicle Systems Engineering and Technology Symposium (GVSETS) Rapid Production of Hydrogen Rich Syngas, Pearlman et al. Page 3 of 9 the temperature of the gas molecules and ions; the electrons subsequently participate in dissociation and ionization reactions that promote syngas production without substantial heating of the gas mixture. In our system, heating of the gas mixture is largely provided from the exothermicity of the partial oxidation process together with heat recuperation from the hot reformate with a limited amount of heating provided from the electrical discharge. Non thermal plasmas can further be divided into two classes: \"cold\" and \"warm.\" Both classes generate a pool of active species that serve a similar role as a catalyst. Cold plasmas, including dielectric barrier discharges (DBD) coronas, and pulsed coronas, do not provide heating of the gas, and are usually used in applications requiring low process temperature and low power density, such as surface treatment, ozone production, and disinfection [12] \"Warm\" discharges are intermediate between cold and thermal plasmas and include low current arcs, glow discharges [13] microwave discharges [10,11] and gliding arc discharges [5] Gliding arc discharges are especially well suited for fuel reforming since their temperatures are in the 800 1000oC range, which is similar to that needed for traditional reforming. In terms of prior studies on plasma reforming, notable contributions include work by the Drexel Plasma Institute who used a gliding arc plasma reactor for steam or dry reforming of JP8 with H2O and CO2; here, the H2O and CO2 represent the products of an SOFC exhaust stream [2] Also, Ceramatec has developed a plasma reformer for reforming diesel", "author_names": [ "Howard G Pearlman", "Brian F Schwartz", "Max Demydovych", "Chien-Hua Chen", "Alexander Rabinovich", "Shridhar Shenoy", "Alexander A Fridman" ], "corpus_id": 111387427, "doc_id": "111387427", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Rapid Production of Hydrogen Rich Syngas Using a Non Thermal Plasma Fuel Reformer", "venue": "", "year": 2018 }, { "abstract": "Thermo catalytic thermal cracking processes refer to processes of the chemical industry whose input raw material are solid, liquid or gas state hydrocarbons. The purpose of technology is to produce a liquid and gas state hydrocarbon fraction with higher value. As a starting point in our research, we examined thermal cracking of solid and/or rubber waste by means of a fixed and fluid bed (semi batch) complex reactor system using a catalyst at 450 degC. Common features of these operations of the chemical industry are the inertised atmosphere, temperatures between 400 and 450 degC and a pressure range close to the atmosphere. However, the selected reactor design may imply a considerable difference as it largely determines the distribution and quality parameters of the valuable products formed. Our publication discusses the optimisation possibilities of reactor constructions of diverse types based on the values measured with the equipment constructed by us and experiences. 1. PRESENTATION OF THERMAL CRACKING PROCESSES Recycling various plastic and rubber waste sorts thermo catalytically has been drawing more and more attention in the last years as valuable raw materials for the chemical industry and energy carriers can be generated this way. Moreover, it is worth noting that considerable environmental and waste treatment issues can become resolvable, too. One of the most important operational units of the process is the reactor, in which the degradation, more precisely the chemical conversion of the solid raw material occurs with the impact of a catalyst and inert fluid mixer. However, it is a relevant fact that solid raw material processing thermal cracking technologies face a number of important challenges. The design and operation of catalytic cracking reactors is difficult due to the poor thermal conductivity factor and extremely high viscosity of molten polymer. Types used in a broad range applications are the following: batch/semi batch reactors; fixed bed reactors; fluid bed reactors; MultiScience XXXI. microCAD International Multidisciplinary Scientific Conference University of Miskolc, Hungary, 20 21 April 2017 ISBN 978 963 358 132 2 DOI: 10.26649/musci.2017.066 streamed bed reactors; screw press (extruder) reactors. Our work leveraged a combined design laboratory scale (capacity: 40 g/h) semibatch operated fluid and fixed bed reactor system by means of which experimental measurements were performed under thermal and thermo catalytic circumstances at 450 degC. 2. ANALYSIS OF REACTOR TYPES OF THE THERMAL AND THERMOCATALYTIC THERMAL CRACKING PROCESSES The selection of reactor type(s) appropriate for the solid raw material to be processed is key in the process as it affects directly both the quality and quantity of the product formed. 2.1. Batch/semi batch reactors Many studies on thermo catalytic plastics cracking in mixed (not in each case) batch or semi batch reactor are available in the professional literature [1] The main reason for this is principally the easy designability and operability. In the case of semi batch reactors, a stream of continuous inert gas (nitrogen in general) is generated, which removes the volatile components from the vapour space at the temperature of reaction. The removal of volatile products minimises the possibility of the secondary cracking (e.g. via oligomerisation, cyclisation and aromatization) of primary cracking products. This process 'takes a back seat' in a batch reactor as there the secondary cracking is 'brought to the fore' [2] Lee et al. examined the catalytic degradation of plastic waste (HDPE high density polyethylene) LDPE (low density polyethylene) PP (polypropylene) and PS (polystyrene) on FCC (fluid catalytic cracking) catalyst in a semi batch mixed reactor [3] The yield of liquid products depending on the plastics of various types at 400 degC was as follows: PS PP PE (HDPE, LDPE) The quantity of liquid products was over 60 in each case. In the catalytic case, the solid remains were below 1 m/m% except for PS, where it was about 5 m/m% To avoid the mentioned secondary cracking, we decided to operate the verticallypositioned fluid bed tube reactor in our work in a semi batch manner with the continuous stream in of nitrogen. 2.2. Fixed bed reactors Fixed bed reactors are probably listed among the most classic reactors. However, there use with plastics is not easy as these materials have an elevated viscosity and low thermal conductivity factor, due to which extremely serious issues can arise even at the feed in. In specific cases, the molten polymer fraction is introduced to the reactor [4] via a capillary tube from the tank under overpressure. The most frequent technical solution is to perform a so called preventive thermal cracking. Next, the liquid or gas components originating from the thermal cracking can be simply transferred onto the fixed bed [5, 6] in a simple fashion. In our experiments, the role of the fixed bed outlined above was played by the horizontal tube reactor operated at 300 degC as the product vapours formed coming from the vertically positioned operational unit were transferred directly in here, which can actually be regarded as a preventive thermo catalytic cracking as well. 2.3. Fluid bed reactors Fluid bed reactors are characterised by homogeneity in terms of temperature and product composition. This is a remarkable advantage in the cracking of polymers as a thermal gradient develops due to the generally low thermal conductivity factor and high viscosity, leading to developing other reaction systems as heat does not transfer uniformly everywhere. One of the most known processes for the pyrolysis of plastic waste is the Hamburg process developed by Kaminsky et al. [7] The reactor was heated with a heating filament with a power of 5 kW. The raw material was in fed by two screw conveyor belts. The products produced in this way underwent a thorough separation, composed of a cyclone, coolers and electrostatic separators, too. Initially this system was used for thermal cracking of waste polymers exclusively, thereby using nitrogen or pre heated vapour as fluidising agent [7] At a conversion of 90 m/m% oil and waxy products formed, whereas oil had 40% BTX (benzene, toluene, xylene) at higher temperatures (690 to 735 degC) [7] In our work, we noticed that the conversion was almost 90% already at 450 degC with the reactor combination selected by us as we mixed 10 w% catalyst into the raw material and the NiO coated metal mesh, which was also responsible for the establishment of the homogeneous temperature field. The oil produced in our case contained 40% BTX fraction, too (Table 1) because the product vapours could be in direct contact with the catalyst attachment in the horizontal tube reactor. 2.4. Streamed bed reactors One of the first proposals to recycle plastic waste was to crack them directly together with standard FCC raw materials in a combined material flow in FCC refining units. In this line of thinking, a new reaction system is established in a streamed bed. The in feeding contains normally mixed plastic (PE, PP, PS) at 5 10 m/m% light oil (LCO) vacuum gas oil (VGO) or benzene [8] The key element of the process is the internal recirculation reactor, which can ensure little contact time (1 to 10 s) and can operate at a ratio of C/O 6 (catalyst/oil ratio) The catalyst is placed in a basket and gases circulate through the basket via a streaming enforced by a turbine. At time 0, in feeding takes place by injection, when the reaction is finished, the valve opens and the products flow into a vacuum chamber [8] Cracking PE/LCO and PP/LCO mixtures on a HZSM 5 catalyst resulted in the formation of mainly C5 C12 hydrocarbon and aromatic type product as well as small quantity of C1 C2 gas and chark at 450 degC in the ascending simulator [8] 2.5. Screw press (extruder) reactors Screw press (extruder) reactors provide assistance for thermo catalytic cracking of plastic and plastic oil mixture by opening up a novel reaction system [9 11] What is interesting about the process is that the design of the reactor reminds of extruders, which are also used for a broad range of polymer processing applications. The equipment is shown in Figure 1 in a schematic form. Figure 1 Schematic of a screw press reactor [10] The reactor has one hopper where the plastics and plastic oil mixtures can be infed. The externally heated furnace operates at 250 to 300 degC in a nitrogen atmosphere (at a pressure somewhat higher than the atmospheric one) [9 11] The molten reaction mixture is then forwarded into the reactor body, which means essentially a stainless steel tube meaning the current reaction zone at the same time. The tube is heated externally by two tube furnaces, whose temperatures can be regulated irrespective of each other, thus, the reactor can be split up into two heating sections (marking T1/T2) The temperature can be continually regulated with a series of integrated thermoelements to avoid the probability of formation of cold/colder points that would lead to the hardening of plastic. The revolution of the screw press can be varied between 0.5 and 25 rpm, as a result of which the residence time of melt can be defined, too. Due to the small screw diameter, the radial temperature profile is technically negligible. The catalyst is mixed with the plastic in the hopper as this ensures the homogeneous reaction mixture and consequently the identical stream image in the entire system. The catalyst can be recovered at the output point with a simple filtering [9 11] Unlike in other reaction systems, no viscosity issue arises in this reactor as the extrudes squeezes out the material, therefore, the plastic phase can be fed in the hopper continually without any flow issue. This is a significant benefit in contrast to conventional fixed bed reactors where plastic moves simply gravitationally or the feed in is provided from a previous thermal cr", "author_names": [ "Andor Zsemberi", "Zoltan Simenfalvi", "Arpad Bence Palotas" ], "corpus_id": 139139436, "doc_id": "139139436", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Presentation of Reactor Types for Thermo Catalytic Thermal Cracking", "venue": "", "year": 2017 }, { "abstract": "Introduction Waveforms are an important issue in magnetic stimulation. They provide the key to an important characteristic of neurons: their distinctive nonlinear dynamics. Different waveforms seem to have different activation sites and may allow selective stimulation. This is reflected for example by their different corticospinal D and I wave patterns Di Lazzaro, 2004 However, available pulse types are very restricted. In essence, the only established waveforms are monophasic and biphasic pulses. In addition to selective stimulation and neuromodulation, higher efficiency Goetz, 2012 could enable highly focal small coils to overcome thermal issues and provide high repetition rates. Objectives Current devices can only provide very distinct pulses for technological reasons. Even in alternative, more flexible approaches, the underlying circuitry is limited to a certain class of stimuli. Among these stimuli, only a subclass does not change the device state of charge and can therefore be generated repetitively. Our objective was to conceive and design a technology that is able to generate almost any waveform. Accordingly, the selection of waveforms would no longer depend on device capabilities and technology, but merely follow the user's needs. Methods For this aim, we had to abandon all traditional concepts and designs for pulse generation in magnetic stimulation as well as other fields of science and engineering. We developed novel topologies that can handle the special requirements of magnetic stimulation pulses, namely high voltage, high current and high speed. The winning approach uses a dynamical reconfiguration of small energy storages: Metaphorically speaking, it uses a high number of small voltage batteries that can be combined in any parallel and series connection dynamically changeable for every time step so as to exactly control the coil voltage accurately to the curve outlined by the desired waveform. The key components of the technology are no longer expensive high voltage semiconductors, but inexpensive mass produced devices used in consumer electronics. We designed a control strategy for the distributed concept and implemented a prototype for characterization of the concept. Results The system can generate almost any waveform, both existing and potential future pulse shapes. All waveforms can be generated with a recovery of the pulse energy from the coil, which has been known from biphasic stimulators. We achieved this even for classical monophasic waveforms, which can except for rare research devices Schmid et al. 1993 provide high pulse repetition rates, although being preferred. The high losses prevent that. Furthermore, the generation of waveforms is not done by any mechanical reconfiguration, but controlled dynamically. Therefore, the system can even fundamentally change the waveform from pulse to pulse in a theta burst or double pulse protocol. Conclusion The generation of arbitrary waveforms is possible and has several advantages also for classical waveforms. Among others, this includes the ability to use high repetition rates for almost every waveform and profit from cost effective mass produced components.", "author_names": [ "Stefan Gotz", "Florian Helling", "Thomas Weyh" ], "corpus_id": 53144280, "doc_id": "53144280", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "P 232. Leaving the beaten track of TMS waveform restrictions: Concepts and prototype for a 'convertible' stimulator that can generate almost every type of existing and future waveform", "venue": "Clinical Neurophysiology", "year": 2013 }, { "abstract": "As the demand for energy continues to grow with population in emerging countries, use of alternative renewable sources of energy is imperative for the near future. The impending climate change and current economic development have forced a shift to more sustainable sources of energy like geothermal, solar, and wind. The widening of supply demand gap over years has led to global energy crisis and resulted in exhaustive use of non renewable natural resources to meet the energy demands. This extensive use of fossil fuels has been made possible by the current development of human civilization. However, burning of fossil fuels, which are becoming increasingly scarce, has led to an increase in emissions of carbon dioxide, which is a greenhouse gas, into the atmosphere. This, in turn, has also led to a detrimental impact on the environment and an imbalance in the natural ecosystem. Geothermal energy is a green, environmentfriendly, low carbon, renewable and sustainable source of energy since there are relatively less investments and is pollutant free. The major advantage of geothermal energy over other sources of renewable energy is that the underground heat/energy mining does not depend on the weather conditions and geothermal power runs at a much higher load factor than wind or solar. Nearly 40% of the total investment cost that goes into setting up a geothermal plant is the drilling cost. However, this problem can be potentially tackled by utilizing the currently decommissioned and abandoned oil and gas wells for geothermal purposes. Retrofitting an abandoned well to produce geothermal energy also saves the cost of exploring sites for geothermal fields. The estimated potential for the geothermal energy that can be harnessed in India is about 10 million kW. In this study, abandoned oil and gas wells have been simulated as a source of geothermal power to generate electricity. Simulations have been performed by coupling thermal reservoir with bore well heat transfer and laminar flow model. Water, which is chosen as working fluid is circulated down through the annulus and extracted back through the shorter insulated inner pipe. A parametric study to assess the production temperature using finite element method with various operating parameters such as injection mass flow rate, re injection temperature, well depth and geothermal gradient is performed. The results of this study indicate that heat extraction rate increases with increasing mass flow rate as well as the well depth while all other injection parameters remain constant. At higher injection temperature, the net heat extraction rate from the reservoir decreases with time due to lower temperature difference between injected fluid and reservoir formation temperature.", "author_names": [ "A Shah", "S N Pandey", "Vikram Vishal", "Sandip Kumar Saha" ], "corpus_id": 211566630, "doc_id": "211566630", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Modeling of heat transfer in abandoned oil and gas wells", "venue": "", "year": 2019 }, { "abstract": "This thesis describes the work undertaken over three years into the investigation of the effect of proton irradiation on the fatigue crack behaviour of an austenitic stainless steel. Many in core nuclear reactor components that are subjected to radiation damage and repeated thermal stresses are made from austenitic stainless steels. A thorough understanding of the effect of the material changes caused by the radiation damage on the fatigue cracking behaviour is essential for safely extending the lifetime of nuclear plant components. Proton irradiation from an ion accelerator has been used in this study as a surrogate for the neutron irradiation experienced by real components. Despite the different interactions of protons and neutrons with matter, under certain conditions, proton damage can result in a similar damaged end state to neutrons. In contrast to reactor neutrons, accelerated protons can be produced at a higher rate, allowing component end of life damage levels to be reached in a much shorter time. A review of the literature identified thermoelastic stress analysis (TSA) as the technique most capable of measuring the required variables during a fatigue crack growth test, i.e. stress intensity factor and plastic zone size. Two key gaps in the literature were identified. Firstly, few studies of fatigue crack growth in irradiation damaged specimens exist and those that do typically report a small number of specimens. Due to the inherent variability of fatigue crack growth, a large number of specimens should be tested at each damage level to obtain statistically meaningful data. Secondly, fatigue crack growth studies rely on analytical relations based on crack length for both stress intensity factor and plastic zone size measurements in many cases. Using TSA allows direct measurement of these quantities and hence a deeper understanding of the actual specimen behaviour. A novel method was developed to measure the extent of the cyclic plastic zone based on the in phase second harmonic temperature signal. This allowed measurement of the plastic zone area, without prior knowledge of the yield strength. Further, the total energy dissipated from the plastic zone could be calculated, without assuming the plastic zone size and shape. Investigations of the second harmonic temperature data revealed signals originating in the crack flanks that were demonstrated to be related to crack closure. This allowed a simple binary check for closure without further data analysis. A number of austenitic compact tension specimens were prepared and irradiated using accelerated protons at a set of increasing proton fluence levels. Following irradiation, the specimens were loaded in fatigue and imaged regularly with a TSA system as the crack grew. This gave simultaneous measurements of plastic zone size and effective stress intensity factor, and represented the first time the TSA technique has been used to investigate radiation damaged material. The experimentally obtained stress intensity factors and crack growth rates were fitted using the Paris' Law model and analysis of covariance suggested that there is not a statistically significant difference in the gradient of the fit with increasing irradiation damage. However, a significant effect (p 0.05) was found in the offset value. This suggests that greater radiation damage causes a greater reduction in crack growth rate, in agreement with literature. Measurements of the TSA output suggest that, contrary to theory, the apparent plastic zone increased in size with more radiation damage. However, the dissipated energy from the plastic zone did tend to increase with radiation damage. Hence, it is hypothesised that the physical plastic zone decreases in size due to the greater hardness induced by the irradiation, but emits a larger amount of energy as the vacancies and interstitials generated by the radiation damage make dislocation movement more energetically difficult, resulting in an apparent increase in plastic zone size when measured using the TSA system.", "author_names": [ "Rory P Spencer" ], "corpus_id": 219846104, "doc_id": "219846104", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fatigue crack growth behaviour in proton irradiated austenitic stainless steel", "venue": "", "year": 2019 }, { "abstract": "Feldspar in ordinary chondrites (OCs) is often associated with thermal metamorphism, as a secondary mineral that forms from the crystallization of matrix and chondrule mesostasis. However, studies of feldspar in equilibrated OCs show that there is a range of plagioclase compositions within chondrules, some of which may be primary products of chondrule crystallization. It is important to recognize primary feldspar within chondrules because it can be used to help understand the secondary effects of thermal metamorphism and aqueous alteration. The presence of primary feldspar also provides important petrologic constraints on chondrule formation timescales. We undertook a careful study of Semarkona (LL3.00) and observed feldspar in 18% of chondrules. The feldspar is plagioclase covering a wide range of compositions (An2 An99) with little K feldspar component <Or3) We show that plagioclase is a primary igneous phase, based on grain morphology and compositions consistent with growth from a melt having the bulk compositions of the host chondrules. Based on experimental studies, the presence of plagioclase suggests chondrules cooled slowly at temperatures close to the solidus. We also observed several secondary features consistent with the aqueous alteration. These features include zoning of Na and Ca in plagioclase, heterogeneity in plagioclase compositions in altered chondrules, development of porosity from the dissolution of chondrule glass, and alteration of glass to phyllosilicates. Alteration of major Al bearing phases, like plagioclase and glass, has important implications for interpretations of ages derived from Al Mg dating of chondrules, if they have been affected by secondary processes. Introduction Feldspar in ordinary chondrites (OCs) is commonly considered to be a secondary phase that forms during thermal metamorphism. As chondrule mesostasis glass, often feldspathic in composition, and chondrite matrix recrystallize, plagioclase and other phases develop in what has historically been treated as a solid state, temperature dependent process (Huss et al. 2006) The classification scheme of Van Schmus and Wood (1967) used to differentiate degrees of thermal metamorphism, describes the crystallization of chondrule mesostasis into albite as an important feature of the effect of thermal metamorphism. According to this classification scheme, fine grained albite crystallizes by petrologic type 4 and then undergoes textural equilibration through types 5 and 6, ultimately resulting in grains of albite >50 mm in size (Huss et al. 2006; Van Schmus and Wood 1967) However, recent studies of feldspar in equilibrated OCs (Kovach and Jones 2010; Lewis and Jones 2016) show that the general model of Van Schmus and Wood (1967) does not fully define the feldspar equilibration process or the range in compositions and textures found in OC feldspar. Plagioclase is not solely albitic in composition and a wide range of plagioclase compositions (An2 An88) is present in relict chondrules in type 4 L and LL chondrites (Kovach and Jones 2010; Lewis and Jones 2016) Only in type 6 chondrites is feldspar equilibrated chemically, as well as texturally, to an albitic composition of ~An11. The wide range of feldspar compositions within chondrules in type 4 L and LL chondrites is plausibly derived from variable initial mesostasis compositions. However, chondrules may also contain primary igneous plagioclase, with a range of compositions that could reflect the compositions of plagioclase observed in type 4 OCs. Primary, igneous anorthitic feldspar has been described in Type I chondrules in OCs (Huss et al. 2001; Russell et al. 2000) but it is not well characterized, unlike similar occurrences in carbonaceous chondrites (CCs) (Brearley and Jones 1998; Wick and Jones 2012) Al rich chondrules in OCs also contain primary anorthite that is useful for age dating using Al Mg systematics (e.g. Huss et al. 2001) Although Type II chondrules in OCs are relatively rich in Na and K, albitic plagioclase or alkali feldspar is not generally observed (Jones 1990) Grossman and Brearley (2005) noted that crystalline albite is present within some Semarkona chondrules, but did not indicate whether it is primary or secondary in origin. To understand how secondary plagioclase develops during metamorphism, it is essential to know the abundance and composition of primary plagioclase. The mineralogical and chemical changes that affect chondrule mesostasis during thermal metamorphism depend on the composition and initial crystallinity of the mesostasis, in addition to temperature and available fluids. The presence of primary feldspar can influence the subsequent crystallization of the mesostasis glass by providing surfaces on which secondary plagioclase can nucleate. Plagioclase is also affected by alkali metasomatism, so secondary effects recorded in primary plagioclase can provide an indicator of the presence of fluids in type 3 chondrites. Plagioclase alteration can affect Al Mg systematics resulting in low precision isochrons or ages that are difficult to interpret. In addition to its importance in terms of interpreting metamorphism, understanding the origin and development of primary feldspar can help constrain chondrule cooling rates, an important parameter in chondrule formation models (Connolly and Jones 2016) We have investigated the presence and characteristics of primary igneous plagioclase within chondrules of the LL3.00 chondrite Semarkona. Semarkona is the least thermally metamorphosed OC fall with a maximum metamorphic temperature estimated to be less than 260degC (Alexander et al. 1989) It is the ideal sample in which to investigate primary chondrule minerals because chondrule mesostasis glass has not undergone crystallization (Huss et al. 2006) The mineralogy and petrology of Semarkona chondrules were studied extensively by Jones and Scott (1989) and Jones (1990, 1994, 1996) but primary igneous plagioclase was not recognized in those studies. Marked improvements in SEM technology has enabled higher resolution investigations into chondrule mineralogy and allowed for studies on phases too small to be fully characterized in earlier studies. We show that primary igneous plagioclase is abundant in Semarkona chondrules and that careful observations of plagioclase are important for interpreting the effects of metamorphism, alteration, and the results of Al Mg isotope systematics. Samples Analytical Methods For this study, we examined a single thin section of Semarkona from the Institute of Meteoritics Collection at the University of New Mexico, UNM 549. Feldspar was identified using backscattered electron (BSE) imaging and energy dispersive spectroscopic (EDS) analysis on an FEI Quanta 3D Field Emission Gun Scanning Electron Microscope (FEG SEM) at the University of New Mexico. High contrast BSE images were captured at 10 kV and 16 nA. Cathodoluminescence (CL) images were acquired at the Williamson Research Centre, University of Manchester using a CITL Cold Cathode CL 8200 MK3 with optical stage operated at 15 20 kV and 300 400 mA. Quantitative wavelength dispersive spectroscopic (WDS) analysis was performed on a JEOL 8200 Electron Probe Microanalyzer (EPMA) at the University of New Mexico operated at 10 15 kV and 10 nA with a focused beam. The low accelerating voltage was used to minimize the interaction volume when analyzing small feldspar grains. We used the following standards: Taylor olivine (Mg, Fe) Taylor albite (Na, K) Taylor orthoclase (K, Al, Si) and a doped diopside (Ca, Cr, Mn) We used time dependent intensity corrections on Na using the Probe for EPMA software to compensate for the effects of Na migration in Na bearing plagioclase during focused beam analysis. We determined bulk silicate compositions for four chondrules, based on quantitative WDS maps obtained using the EPMA. 300x300 pixel maps were acquired in two passes using an 80 ms/px dwell time and a 1 3 mm spot size. This provided coverage of between 300x300 mm and 900x900 mm, depending on the size of the chondrule. The resulting intensity maps were processed using mean atomic number (MAN) background corrections to produce quantitative oxide maps. MAN curves were generated using the following Taylor standards: olivine, albite, orthoclase, chromite, spessartine, MgO, hematite, and nickel and additional standards: doped diopside, labradorite, and sodalite. Chondrules were masked in Adobe Photoshop and the bulk silicate compositions of the chondrules were calculated. We used a custom MATLAB script to identify the chondrule pixels in which analytical sums lie between 90% and 110% In addition, pixels with SiO2 content less than 20% were omitted to eliminate Fe Ni metal and sulfides. Densities were determined for each pixel based on the assigned mineral phase and the bulk silicate composition of each chondrule was calculated as the mean density weighted composition of accepted", "author_names": [ "Jonathan A Lewis", "Rhian H Jones" ], "corpus_id": 134168586, "doc_id": "134168586", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Primary feldspar in the Semarkona LL3.00 chondrite: Constraints on chondrule formation and secondary alteration", "venue": "", "year": 2019 }, { "abstract": "Very thin, thermally evaporated MoOx (x 3) layer has been used as transparent hole selective contact on an ntype Germanium substrate to effectively demonstrate PV conversion capability. The fabricated MoOx/Ge heterojunction PV cell shows a photocurrent density of 44.8 mA/cm under AM1.5G illumination, which is comparable to that of conventional Ge PV cells. However, a low open circuit voltage of 138mV is obtained, which might be explained by the presence of tunnelling mechanisms through the MoOx/Ge interface. To our knowledge, this is the first demonstration of a hole selective contact made of transition metal oxide on an n type semiconductor different from c Si. Thus, this work may have important implications toward the development of new device architectures, such as novel low cost Ge PV cells with possible applications in multijunction solar cells and thermophotovoltaics. Historically, the driving force for the use of Ge in photovoltaic (PV) applications has been as a substrate for GaAs space solar cells (Miller and Harris, 1980) the main reason being the higher thermal conductivity and the possibility of manufacturing thinner and lighter wafers with Ge than with GaAs. Later on, Ge/GaAs tandem solar cells were pursued to enhance the conversion efficiency (Chand et al. 1986) by using the Ge bottom cell to convert the infrared part of the solar spectrum. This progress eventually derived in the development of the current standard technology for space solar cells that consists of triple junction Ge/GaAs/GaInP structures, with AM0 conversion efficiencies in the range of 28 30% These cells have been also used in terrestrial applications within concentrated PV (CPV) systems, where they reached AM1.5D conversion efficiencies of 41.6% King et al. 2009) just below the current world record for solar to electricity conversion efficiency of 46.0% (Dimroth et al. 2016) Apart from solar applications, Ge PV cells have been considered as a low cost replacement for low band gap III V semiconductors in thermophotovoltaic (TPV) converters, in which thermal radiation is directly converted into electricity by infrared sensitive PV devices (Bauer, 2011; Chubb, 2007) In this context, Ge TPV cells could be used in a broad range of applications such as waste heat recovery (Bauer et al. 2003) solar thermal power (Ungaro et al. 2015; Lenert et al. 2014; Datas and Algora, 2013) space power (Datas and Marti, 2017) and energy storage (Datas et al. 2016) among many others. Current state of the art of Ge PV cells consist of p n junctions created by diffusion of dopants at high temperatures (Bitnar, 2003) For instance, p n junctions in p Ge have been created by diffusion of Vgroup atoms (typically P and As) during the first growing step of GaInP or GaAs nucleation layers within a Metal Organic CVD (MOCVD) reactor at temperatures of ~650 degC (Fernandez et al. 2008; Fernandez, 2010; Barrigon Montanes, 2014) Other groups have used the diffusion of Zn in n Ge substrates within a LPE reactor (Khvostikov et al. 2002) In an effort to reduce manufacturing costs of standalone Ge PV cells, IMEC reported devices with p n junctions created by spin on diffusion of P on p Ge by rapid thermal annealing at different temperatures (450 700 degC) (Posthuma et al. 2007; van der Heide, 2009; van der Heide et al. 2009) leading to the best reported 1 sun AM1.5G conversion efficiency for stand alone Ge PV cells of 7.9% (van der Heide et al. 2009) Surface passivation has been accomplished by forming different kinds of heterojunctions on Ge surface, such as Ge/GaAs (Khvostikov et al. 2002) or Ge/GaInP (Fernandez et al. 2008; Fernandez, 2010; Barrigon Montanes, 2014) by MOCVD or LPE (Khvostikov et al. 2002) or Ge/a Si (Posthuma et al. 2007; van der Heide, 2009; van der Heide et al. 2009; Posthuma et al. 2005) Ge/ SiNx (Nagashima et al. 2007) and Ge/a SixC1 x (Fernandez et al. 2008; Fernandez, 2010; Weiss et al. 2018) by PECVD. In order to further reduce the fabrication cost of Ge PV cells, it is desirable to eliminate the high temperature diffusion, and complex MOCVD or PECVD processes. In this regard, a particularly appealing option consists of substituting the doping step by carrier selective coatings with surface passivation properties that could be deposited at low temperatures. For this purpose, high electron affinity transition https:/doi.org/10.1016/j.solener.2019.02.009 Received 29 August 2018; Received in revised form 21 January 2019; Accepted 6 February 2019 Corresponding authors. Solar Energy 181 (2019) 357 360 0038 092X/ (c) 2019 International Solar Energy Society. Published by Elsevier Ltd. All rights reserved. T metal oxides (TMOs) such as MoO3, WO3, and V2O5, are very interesting candidates that have already been found effective to produce hole selective contacts on both n type and p type c Si (Gerling et al. 2015; Battaglia et al. 2014; Bullock et al. 2014; Vijayan et al. 2018) In this letter we report a Ge PV cell formed by a thin sub stoichiometric MoOx (x 3) layer on top of an n type crystalline Ge (c Ge) substrate, which behaves as a hole selective contact. To our knowledge, this is the first demonstration of a hole selective contact made with a TMO on an n type semiconductor different than c Si. Thus, it might open the door to new device architectures, not only for PV applications, but also in photonics and CMOS electronics, where the integration of TMOs is being investigated (Sanchez et al. 2016) along with the use of different semiconductors having higher carrier mobilities and extended spectral response than c Si, such as Ge (Reboud et al. 2017; Toriumi and Nishimura, 2017) The PV cell structure was fabricated on (1 0 0) oriented, Czochralski, n type Ge substrates (r=0.37O*cm, 350 mm thick) The substrate was cleaned by HCl: H2O (33% immediately prior to rear side passivation by PECVD of (i/n) a SiCx:H (4/15 nm, x~ 0.2) and a SiC (80 nm) stack deposited at ~300 degC. Next, the rear contact was created by laser firing of the a SiC stack to produce an array of ~60 mm diameter local diffusion points, separated by 600 mm pitch. This distance was chosen to introduce reasonable series resistance of ~0.1Ocm (Fischer, 2003) Laser firing was accomplished by means of a ~1200mW, l=1064 nm Nd/YAG laser system at a frequency of 4 kHz with 6 pulses per spot, following a similar approach developed for c Si devices (Lopez et al. 2018) The rear contact was finalized by means of an e beam evaporated Ti/Pd/Ag metal stack that provides lateral interconnection between fired points. The hole selective contact was formed at the front side of the device by means of very thin (nominally 20 nm) MoOx layer thermally evaporated from powdered MoO3 sources at ~8*10 mbar and a deposition rate of ~0.2 A/s (Gerling et al. 2015) A 75 nm thick ITO layer was subsequently deposited by RFSputtering on top of the MoOx layer to increase lateral electrical conductivity and minimize optical reflectivity. A sketch of the full PV cell structure and the TEM image of the MoOx/ITO interface are shown in Fig. 1, where a pronounced inter diffusivity between the layers is clearly observed. The 1x1 cm active area of the PV cells was defined by conventional lithographic techniques followed by mesa etching of the MoOx/ITO layers. Finally, the front Ag grid electrode (2 mm thick) was evaporated through a shadow mask for a 4% contacted area. One sun I V characterization of the PV cell was performed at 25 degC using a ORIEL 94021A (Newport) solar simulator, where the distance between the cell and the lamp was varied until the photo generated current density coincides with the one calculated through the integration of the cell' experimental external quantum efficiency (EQE) and the AM1.5G spectrum with 100mW/cm. The corresponding current density voltage (J V) curve under 1 sun illumination is shown in Fig. 2. The short circuit current density (JSC= 44.8mA/cm) outperforms that of the best performing state of the art Ge PV cells (43.2mA/cm) (van der Heide et al. 2009) On the other hand, a much lower open circuit voltage (138mV) is measured, compared to those reported in (Fernandez, 2010; van der Heide et al. 2009) (up to 265mV) which ultimately results in a lower FF (40.9% partially due to a non optimized metal grid that introduces a series resistance of 0.65 Ocm. As a result, an AM1.5G conversion efficiency of 2.53% is obtained. External quantum efficiency (EQE) of the PV cell is shown in Fig. 3 at short circuit conditions along with the EQE of Ge PV cells reported in (van der Heide, 2009) for a direct comparison. The improved EQE for wavelengths shorter than 600 nm might be explained by the reduction of the recombination close to the front surface compared to the one existing in the highly doped emitters (10 10 cm) used in (van der Heide, 2009) Such a low recombination does not necessary indicate a good chemical surface passivation, i.e. strong reduction of interface state density, but it could be related to a strong electric field that unbalances carrier densities, i.e. field effect passivation. The electric field located at the surface creates an electrostatic potential which, under thermal equilibrium, is the potential barrier built at the junction (Vbi) Then, the higher Vbi, the stronger the electric field and, thus, the better the surface passivation. In order to measure Vbi, capacitance voltage measurements of the cell in reverse bias were performed at 10 kHz using HP4294A impedance analyser with a signal amplitude of 30mV following the same approach than in (Almora et al. 2017) where similar structures on c Si substrates are characterized. This data can be Fig. 1. Sketch of the fabricated solar cell. Focus: TEM image of the MoOx interlayer of the final device. Fig. 2. Current density voltage curve of the Ge PV cell manufactured in this work under AM1.5 G illumination conditions. A. Alcaniz, et al. Solar Energy 181 (2019) 357 360", "author_names": [ "A Alcaniza", "G Lopeza", "I Martina", "A Jimenezb", "A Datasa", "Emanuela Callea", "Erlyta Septa Rosa", "L G Gerlinga", "C Voza", "C del Canizob", "Ramon Alcubillaa" ], "corpus_id": 203630502, "doc_id": "203630502", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Germanium photovoltaic cells with MoOx hole selective contacts", "venue": "", "year": 2019 }, { "abstract": "The ISIS Neutron and Muon Source, based at the Rutherford Appleton Laboratory, begins with an injector line that accelerates an H ion beam to 70 MeV. The beam then travels through a High Energy Drift Space (HEDS) before passing through an electron stripping foil upon injection into the proton synchrotron, which provides acceleration up to 800 MeV. During machine setup, beam profile measurements in the HEDS are taken using scanning wire monitors, which drive a single pair of measuring wires, one per plane, through the beam aperture using an analogue servo motor. Many of these monitors have been in operation since ISIS was commissioned in 1984 and as such are coming to the end of their operational lifetimes, meaning a new suite of monitors is required. A prototype monitor has been developed along with new electronics and a control system to test the operation of a new drive mechanism based around a stepper motor and resolver, providing increased precision and reliability. This paper discusses the development of a new multi wire monitor design, and the associated upgrade to the electronics and control system. INTRODUCTION The ISIS linac accelerates H ions to 70 MeV, producing a 50 Hz pulsed beam with a pulse length of 200 ms. This beam travels through a HEDS before injection into an 800 MeV proton synchrotron. After acceleration, protons are transferred into one of two Extracted Proton Beamlines (EPBs) and delivered to a tungsten target, driving the neutron spallation process. Measurement of the beam's profile throughout the accelerator is vital during machine setup, whilst also providing valuable information during accelerator studies, and for understanding beam loss mechanisms. Three types of profile monitor are in use around ISIS: wire scanners and wire grid 'harp' monitors, which are both destructive to the beam [1] and Ionisation Profile Monitors (IPMs) which provide non destructive measurements. IPMs are used for profile measurements around the synchrotron ring, as any induced beam loss would quickly build to unsustainable levels over multiple orbits. Non destructive profile monitoring at ISIS is described in further detail in [2] [3] Destructive profile monitors are installed around the HEDS and EPBs and are crucial during machine setup, providing trusted and reliable measurements of the beam. Profiles are taken by moving conducting wires into the path of the beam and measuring the current generated by secondary electron emission, induced as beam particles pass through the wires. ISIS is operated at a slower rate of 1.6 Hz while these monitors are in use, reducing both the levels of induced beam loss and the risk of damage to the measuring wires. Harp monitors are installed along both EPBs, consisting of retractable grids of wires which are inserted into the beam aperture using a pneumatic system. The grids contain 24 wires per plane with spacing set to either 6 mm or 10 mm, depending on the beam distribution in each location. Along the HEDS the beam is significantly smaller, with beam widths typically between 10 30 mm. As a result wire scanners are used here instead to allow higher resolution profiles to be measured, in addition to being cheaper to manufacture and causing less beam loss. A single pair of measuring wires is scanned across the beam aperture by a motor driven linear stage, mounted at 45 to the beam (Fig. 1) As a result, wire displacement in both the horizontal and vertical planes is equal when the wire head is moved, with the distance travelled along each plane inversely proportional to the linear stage motion by a factor of 2. The wires are moved through the beam in horizontal and vertical steps, typically of 4 mm, and a reading is taken at each position to build up a 2D profile measurement over multiple beam pulses. Figure 1: Orientation of a wire scanner head, with a signal wire and pair of bias wires mounted in each plane. There are currently 15 wire scanners installed along the ISIS HEDS, many of which have been operational for over 30 years and have surpassed their design lifetimes. As a result a replacement programme is now underway, and a new monitor design has been developed alongside an upgraded control system and electronics. MONITOR DESIGN A prototype monitor of the new design has been built, tested and recently installed in the ISIS HEDS. The monitor offers improved measurement resolution and precision compared with existing monitors, in addition to enhanced reliability. As the motion undergone during measurement ___________________________________________ [email protected] [email protected] 6th International Beam Instrumentation Conference IBIC2017, Grand Rapids, MI, USA JACoW Publishing ISBN: 978 3 95450 192 2 doi:10.18429/JACoW IBIC2017 WEPCC18 WEPCC18 396 Co nt en tf ro m th is w or k m ay be us ed un de rt he te rm so ft he CC BY 3. 0 lic en ce (c) 20 18 A ny di str ib ut io n of th is w or k m us tm ai nt ai n at tri bu tio n to th e au th or (s tit le of th e w or k, pu bl ish er ,a nd D O I. 6 Beam Profile Monitors causes wear in several components, predicted lifetime usage was a key factor during the design phase. All components were selected to ensure a design lifetime of 20 years heavy use, corresponding to 8,000 scanning cycles. Measuring and Bias Wires Silicon Carbide (SiC) coated carbon wires with diameters of 142 mm are used for the measuring wires. This material is an ideal choice due to its rigidity and high emissivity, meaning it does not suffer from excess heating whilst intercepting the beam [4] The wires are left unconstrained at their outermost extent to allow for thermal expansion to occur without causing damage. Instead the wires threaded through small guide holes cut into Macor(r) mounting blocks to ensure they remain aligned during operation. Each measuring wire is flanked by a pair of bias wires (Fig. 1) these can be set to a positive bias voltage of up to 200 V to attract electrons emitted from the measuring wire, preventing recombination from affecting the beaminduced signal during measurement. Motion System A radiation hardened stepper motor, resolver and brake, manufactured by Empire Magnetics, is used to drive the linear stage and wire head through the beam (Fig. 2) [5] Stepper motors rotate in small, discrete steps, ensuring highly accurate levels of rotation. Additionally a strong holding torque is generated while these motors are energised and at rest. An electromagnetic brake, released when supplied with current, is connected to prevent shaft movement when the system is not in use, and provides a safeguard in the event of power failure. Figure 2: Simplified layout of the profile monitor. A 5:1 gearbox is connected between the motor and the linear stage, providing extra protection from the compression force generated by the bellows when the wires are withdrawn from the beam aperture. The resolver provides a measurement of the wire positions, producing signals induced by the motor's rotations which are then passed through a resolver to encoder converter for processing in the motor drive unit. The overall system can theoretically measure the position of the wires to a resolution less than 0.1 mm, comfortably exceeding the precision required. The scanning speed required is set by the reduced rate of 1.6 Hz at which ISIS is operated during measurement. Movement of the wires between each scan position is completed during the time between adjacent beam pulses, ensuring the profile is measured as quickly as possible. Honeywell 9HM1 microswitches, suitable for use in radiation environments, are used as limit switches and positioned to set the linear stage stroke to 156 mm, 6 mm larger than the beam aperture [6] When the monitor performs a profile scan, the wires are centred in the beam aperture relative to these switches, meaning precise switch activation positions are vital. During testing the switches demonstrated excellent precision, with the measured shaft positions at each limit undergoing variations of just 40 mm over 2,000 cycles of operation. Direct Position Measurement A linear potentiometer is attached to the monitor shaft, providing a secondary reading of the wire positions. This is useful for detecting slipping of the monitor's shaft position, which can occur over a number of years. It also provides a method of position measurement in the event of a power failure causing the motor control unit's encoder to reset. The potentiometer measures at a lower resolution of approximately 1 mm but is more robust and provides an independent safeguard to show if the wire head is positioned inside the beam aperture inadvertently. The voltages measured by the potentiometer range between 14 V, chosen so that should anything happen to the 15 V supply fed to the potentiometer it would be instantly visible to the electronics. Radiation Protection The monitor's limit switches and motor systems were selected for their suitability for use in radiation environments, as previously mentioned. However these components are significantly more expensive as a result, and potentially unnecessary as in some monitor locations the expected dose is relatively low. To test these dose levels a TID (Total Ionisation Dosimeter) monitoring system, recently developed at ISIS, will be used to measure radiation levels along the HEDS, to test whether more cost effective components can be used on some of the new monitors [7] ELECTRONICS Setup Two units are used to control the profile monitor: a custom motor control unit, used to control the monitors drive system and provide a live position of the monitor; and a National Instruments cRIO embedded controller, which interfaces with the ISIS accelerator control system and acquires data from the monitor [8] 6th International Beam Instrumentation Conference IBIC2017, Grand Rapids, MI, USA JACoW Publishing ISBN: 978 3 95450 192 2 doi:10.18429/JACoW IBIC2017 WEPCC18 6 Beam Profile Monitors WEPCC18 397", "author_names": [ "Daniel Harryman", "Christopher C Wilcox" ], "corpus_id": 223618719, "doc_id": "223618719", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "An Upgraded Scanning Wire Beam Profile Monitoring System for the ISIS High Energy Drift Space", "venue": "", "year": 2018 } ]

[ { "abstract": "In the past decade, there has been an increasing number of experiments on spontaneous Bose coherence of excitons and polaritons. Four major areas of research are reviewed here: three dimensional excitons in the bulk semiconductor Cu2O, two dimensional excitons in coupled quantum wells, Coulomb drag experiments in coupled two dimensional electron gases, and polaritons in semiconductor microcavities. The unifying theory of all these experiments is the effect of spontaneous symmetry breaking in the Bose Einstein condensation phase transition.", "author_names": [ "David W Snoke" ], "corpus_id": 27590596, "doc_id": "27590596", "n_citations": 267, "n_key_citations": 5, "score": 1, "title": "Spontaneous Bose Coherence of Excitons and Polaritons", "venue": "Science", "year": 2002 }, { "abstract": "Electrons, holes, and photons in semiconductors are interacting fermions and bosons. In this system, a variety of ordered coherent phases can be formed through the spontaneous phase symmetry breaking because of their interactions. The Bose Einstein condensation (BEC) of excitons and polaritons is one of such coherent phases, which can potentially crossover into the Bardeen Cooper Schrieffer (BCS) type ordered phase at high densities under quasi equilibrium conditions, known as the BCS BEC crossover. In contrast, one can find the semiconductor laser, superfluorescence (SF) and superradiance as relevant phenomena under nonequilibrium conditions. In this paper, we present a comprehensive generating functional theory that yields nonequilibrium Green's functions in a rigorous way. The theory gives us a starting point to discuss these phases in a unified view with a diagrammatic technique. Comprehensible time dependent equations are derived within the Hartree Fock approximation, which generalize the Maxwell Semiconductor Bloch equations under the relaxation time approximation. With the help of this formalism, we clarify the relationship among these cooperative phenomena and we show theoretically that the Fermi edge SF is directly connected to the e h BCS phase. We also discuss the emission spectra as well as the gain absorption spectra.", "author_names": [ "Makoto Yamaguchi", "Ryota Nii", "Kenji Kamide", "Tetsuo Ogawa", "Yoshihisa Yamamoto" ], "corpus_id": 119225275, "doc_id": "119225275", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Generating functional approach for spontaneous coherence in semiconductor electron hole photon systems", "venue": "", "year": 2015 }, { "abstract": "Abstract Quasi two dimensional (2D) exciton polaritons in single and coupled quantum wells or quantum dots embedded in an optical microcavity in magnetic field are considered. The dependencies of exciton properties on control parameters are obtained. Magnetic field influence on polariton resonance, splitting and dispersion is studied. Effects of spontaneous coherence and Kosterlitz Thouless transition and Bose Einstein condensation for such systems are discussed.", "author_names": [ "Natalia E Kaputkina", "Yurii E Lozovik" ], "corpus_id": 121574885, "doc_id": "121574885", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Indirect excitons in coupled quantum dots and exciton polaritons in optical microcavities in magnetic field", "venue": "", "year": 2008 }, { "abstract": "Influence of external magnetic field and confinement on direct and spatially indirect excitons is studied. Exciton photon interaction and exciton polariton formation are discussed for single and coupled quantum wells or quantum dots embedded in optical microcavity. Possibility to control polariton resonance, polariton splitting and polariton dispersion by magnetic field is studied analitically and numerically. Magnetic field changes effective mass of magnetoexciton. Magneticfield increases effective steepness of confining potential in quantum dots also. This leads to the transformation of exciton energy spectrum. At low temperatures spontaneous coherence and Kosterlitz Thouless transition to superfluid state of exciton polaritons in the system of coupled quantum wells embedded in microcavity or Bose Einstein condensation of exciton polaritons in the system of coupled quantum dots embedded in optical microcavity can take place. (c) 2009 WILEY VCH Verlag GmbH Co. KGaA, Weinheim)", "author_names": [ "Natalia E Kaputkina", "Yurii E Lozovik" ], "corpus_id": 121312299, "doc_id": "121312299", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Influence of external magnetic field and confinement on spectrum rearrangement and exciton polaritons in optical microcavity", "venue": "", "year": 2009 }, { "abstract": "In this thesis, we study two different aspects of many particle physics. In the first part, we study the Bose Einstein condensation of microcavity exciton polaritons in different artificial lattices. Bose Einstein condensation is a quantum phase transition, which allows the system to macroscopically occupy its ground state and develop coherence spontaneously. Often studied in microcavities, which are optical cavities that trap light at specific wavelengths, exciton polaritons are a kind of quasiparticle arising from the strong coupling between quantum well excitons and cavity photons. By periodically aligning cavity pillars in different patterns, one can achieve different artificial lattice structures. With this setup, we apply the driven dissipative Gross Pitaevskii equations to investigate the different consequences of the condensation by changing the pumping schemes and the design of the trapping potentials. Topics include multivalley condensation, phase selection and intermittency of exciton polariton condensation, flat band condensation, and exciton polariton topological insulators. In the second part of this thesis, we focus on the electron scattering properties of a hybrid Bose Fermi system. We consider a system consisting of a spatially separated two dimensional electron gas layer and an exciton gas layer that interacts via Coulomb forces. We study the temperature dependence of the system's resistivity with this interlayer electron exciton interaction and compare the results with the electron phonon interaction.", "author_names": [ "Meng Sun" ], "corpus_id": 226956200, "doc_id": "226956200", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Exciton Polaritons in Artificial Lattices and Electron Transport in Bose Fermi Hybrid Systems.", "venue": "", "year": 2020 }, { "abstract": "Spontaneous coherence and Kosterlitz Thouless transition to superfluid state of exciton polaritons in the system of coupled quantum wells embedded in microcavity was considered at low temperatures. Contrary to the infinite two dimensional system without confinement, the Bose Einstein condensation of exciton polaritons in the system of coupled quantum dots embedded in optical microcavity can take place. Growth of confining potential steepness fleads to the increase of the critical temperature. Magnetic field influence on the critical temperature can be non monotonous for certain region of control parameters because of the competition of two mechanisms: (i) growth of the effective mass of magnetoexciton which leads to decreasing of critical temperature; and (ii) growth of effective parameter of confinement, which increases the critical temperature and favors condensate formation.", "author_names": [ "Natalia E Kaputkina", "Yurii E Lozovik" ], "corpus_id": 120888259, "doc_id": "120888259", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effects of magnetic field and confining potential on spontaneous coherence of exciton polaritons in coupled quantum wells and dots embedded in optical microcavity", "venue": "", "year": 2012 }, { "abstract": "Microcavity exciton polaritons are the eigenstates resulting from strong light matter coupling in high quality monolithic semiconductor microcavities. Owing to their mixed photonic and excitonic nature, polaritons are Bose particles of very light mass and short lifetime that can interact with their environment, forming a new class of Bose gas. In spite of their short lifetime, a polariton gas can show Bose Einstein condensation or polariton lasing depending on the experimental conditions. The properties of these coherent states of polaritons are unique in many respects. In this chapter we rely on a comprehensive set of experimental and theoretical works carried out this last decade to give a detailed description of polariton coherent states. The influences of finite lifetime, disorder and interaction with the environment are addressed, and the analogies and differences between polariton condensate, polariton lasing, equilibrium Bose gas and photon lasing are outlined and discussed.", "author_names": [ "Maxime Richard", "Michiel Wouters", "Le Si Dang" ], "corpus_id": 117182610, "doc_id": "117182610", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Spontaneous coherence within a gas of exciton polaritons in Telluride microcavities", "venue": "", "year": 2010 }, { "abstract": "The spontaneous breaking of the continuous symmetries of a two dimensional electron hole system in a strong magnetic field perpendicular to the plane leads to the formation of new ground states and determines the energy spectrum of collective elementary excitations that appear above these new ground states. In this review, the main attention is paid to the electron hole system formed from coplanar magnetoexcitons under conditions of Bose Einstein condensation in the ground state with the wave vector k 0 taking into account the influence of excited Landau levels, when exciton type elementary excitations coexist with plasmon type oscillations. At the same time, the properties of a two component system consisting of a two dimensional electron gas and a two dimensional hole gas spatially separated in a double quantum well under conditions of the fractional quantum Hall effect are of great interest, because these properties can affect the quantum states of magnetic excitons that are formed when the distance between the layers tends to zero. Bilayer electron systems are also considered under conditions of the fractional quantum Hall effect with the one half filling factor for each layer and the total filling factor equal to unity for both layers. The coherence between the electron states in the two layers is equivalent to the formation of excitons in a macroscopic coherent state. This makes it possible to compare the energy spectrum of collective elementary excitations of Bose Einstein condensed excitons under conditions of the quantum Hall effect and coplanar magnetoexcitons. The breaking of the global gauge symmetry or of the continuous rotational symmetry leads to the formation of a gapless spectrum of the Nambu Goldstone type, whereas the breaking of the local gauge symmetry is accompanied by the appearance of a gap in the energy spectrum (Higgs phenomenon) These phenomena are equivalent to the formation of massless and massive particles in the relativistic physics. The application of the Nielsen Chadha theorem, which determines the number of Nambu Goldstone modes as a function of the number of broken symmetry operators, is demonstrated using the example of Bose Einstein condensation of spinor atomic gases in an optical trap. This example is presented for a better understanding of the results obtained in the case of a Bose Einstein condensation of coplanar magnetoexcitons. The Higgs phenomenon leads to the formation of composite particles under conditions of the fractional quantum Hall effect. Their description is given in terms of the Ginzburg Landau theory. The possibilities for the appearance of spontaneous coherence in a system of indirect excitons in structures with a double quantum well are analyzed. The experimental attempts to create these conditions, the main results obtained in this field, and the accumulated knowledge are reviewed. The basic properties of the energy spectrum of magnetoexciton polaritons in a microcavity are formulated. A hypothesis is put forward about the possibility of forming two dimensional magnetoexcitons and two dimensional magnetoexciton polaritons of high density with attached point quantum vortices, i.e. about the possibility of forming new composite particles.", "author_names": [ "S A Moskalenko", "Michael A Liberman", "E S Moskalenko", "E V Dumanov", "Ig V Podlesny" ], "corpus_id": 122104870, "doc_id": "122104870", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "Coherence of two dimensional electron hole systems: Spontaneous breaking of continuous symmetries: A review", "venue": "", "year": 2013 }, { "abstract": "Over the last two decades, the system of exciton polaritons (polaritons) in a semiconductor microcavity has become an important platform for studying the physics of quantum fluids in a solid state system. Polaritons are formed by the strong coupling between photons and a sharp electronic resonance (e.g. an exciton resonance) in a cavity. They are interacting bosonic particles with a small effective mass due to their half light and half matter nature. Spontaneous coherence phenomena, such as the superfluid transition and Bose Einstein condensation (BEC) have been observed in polariton systems at temperatures in the range from several Kelvin to room temperature. This dissertation focuses on new methods of trapping polaritons and the BEC and superfluidity of polaritons in these new traps. The first part of this dissertation describes experiments on trapping polaritons with an optically generated potential barrier. When the polariton density increases, there is a transition from ballistic motion to coherent motion of polaritons over hundreds of micrometers. At even higher particle density, there is a very sharp transition from the coherent motion state to the ground state of the trap. The second part of this dissertation explores the superfluid properties of polaritons in a ring shaped trap. This ring trap is formed by combining a stress induced harmonic trap with an optically created barrier at the trap center. This trapping method enables fine control of the trap profile as well as the properties of the polaritons in the trap. The formation of a polariton ring condensate is observed in this trap. The phase and polarization measurement of the ring condensate reveals that it is in a half quantized circulation state which features a phase shift of p and a polarization vector rotation of p of the polaritons around a closed path in the ring. The direction of the circulation of the flow around the ring fluctuates randomly between clockwise and counter clockwise from one shot to the next. In contrast, the rotation of the polarization of polaritons is very stable. This property is experimentally studied, and it is found that the stable spatial polarization pattern may relate to the optical spin Hall effect.", "author_names": [ "Gangqiang Liu" ], "corpus_id": 123776459, "doc_id": "123776459", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Bose Einstein condensation and quantized flow of microcavity polaritons with long lifetime", "venue": "", "year": 2015 }, { "abstract": "Bose Einstein condensate of exciton polaritons in a semiconductor microcavity is a macroscopically populated coherent quantum state subject to concurrent pumping and decay. Debates about the fundamental nature of the condensed phase in this open quantum system still persist. Here, we gain a new insight into the spontaneous condensation process by imaging long lifetime exciton polaritons in a high quality inorganic microcavity in the single shot optical excitation regime, without averaging over multiple condensate realisations. In this highly non stationary regime, a condensate is strongly influenced by the `hot' incoherent reservoir, and reservoir depletion is critical for the transition to the ground energy and momentum state. Condensates formed by more photonic exciton polaritons exhibit dramatic reservoir induced density filamentation and shot to shot fluctuations. In contrast, condensates of more excitonic quasiparticles display smooth density and are second order coherent. Our observations show that the single shot measurements offer a unique opportunity to study formation of macroscopic phase coherence during a quantum phase transition in a solid state system.", "author_names": [ "E Estrecho", "T Gao", "Nataliya Bobrovska", "Michael D Fraser", "Mark Steger", "Loren N Pfeiffer", "Ken W West", "Timothy C H Liew", "Michal Matuszewski", "David W Snoke", "Andrew G Truscott", "Elena A Ostrovskaya" ], "corpus_id": 119058664, "doc_id": "119058664", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Spontaneous condensation of exciton polaritons in the single shot regime", "venue": "", "year": 2017 } ]

[ { "abstract": "Semiconductor Device Physics and Designprovides a fresh and unique teaching tool. Over the last decade device performances are driven by new materials, scaling, heterostructures and new device concepts. Semiconductor devices have mostly relied on Si but increasingly GaAs, InGaAs and heterostructures made from Si/SiGe, GaAs/AlGaAs etc have become important. Over the last few years one of the most exciting new entries has been the nitride based heterostructures. New physics based on polar charges and polar interfaces has become important as a result of the nitrides. Nitride based devices are now used for high power applications and in lighting and display applications. For students to be able to participate in this exciting arena, a lot of physics, device concepts, heterostructure concepts and materials properties need to be understood. It is important to have a textbook that teaches students and practicing engineers about all these areas in a coherent manner. Semiconductor Device Physics and Designstarts out with basic physics concepts including the physics behind polar heterostructures and strained heterostructures.Important devices ranging from p n diodes to bipolar and field effect devices is then discussed. An important distinction users will find in this book is the discussion presented on device needs from the perspective of various technologies. For example, how much gain is needed in a transistor, how much power, what kind of device characteristics are needed. Not surprisingly the needs depend upon applications. The needs of an A/D or D/A converter will be different from that of an amplifier in a cell phone. Similarly the diodes used in a laptop will place different requirements on the device engineer than diodes used in a mixer circuit. By relating device design to device performance and then relating device needs to system use the student can see how device design works in real world. This book is comprehensive without being overwhelming.The focus was to make this a useful text book so that the information contained is cohesive without including all aspects of device physics. The lesson plans demonstrated how this book could be used in a 1 semester or 2 quarter sequence.", "author_names": [ "Umesh K Mishra", "Jasprit Singh" ], "corpus_id": 106654902, "doc_id": "106654902", "n_citations": 182, "n_key_citations": 8, "score": 1, "title": "Semiconductor Device Physics and Design", "venue": "", "year": 2007 }, { "abstract": "", "author_names": [ "Mary Yvonne Lanzerotti", "Robert W Keyes" ], "corpus_id": 200129726, "doc_id": "200129726", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Introductory Semiconductor Device Physics for Chip Design and Manufacturing", "venue": "", "year": 2018 }, { "abstract": "OF DISSERTATION NANOSTRUCTURED SEMICONDUCTOR DEVICE DESIGN IN SOLAR CELLS We demonstrate the use of embedded CdS nanowires in improving spectral transmission loss and the low mechanical and electrical robustness of planar CdS window layer and thus enhancing the quantum efficiency and the reliability of the CdS CdTe solar cells. CdS nanowire window layer enables light transmission gain at 300nm 550nm. A nearly ideal spectral response of quantum efficiency at a wide spectrum range provides an evidence for improving light transmission in the window layer and enhancing absorption and carrier generation in absorber. Nanowire CdS/CdTe solar cells with Cu/graphite/silver paste as back contacts, on SnO2/ITO soda lime glass substrates, yield the highest efficiency of 12% in nanostructured CdS CdTe solar cells. Reliability is improved by approximately 3 times over the cells with the traditional planar CdS counterpart. Junction transport mechanisms are delineated for advancing the basic understanding of device physics at the interface. Our results prove the efficacy of this nanowire approach for enhancing the quantum efficiency and the reliability in windowabsorber type solar cells (CdS CdTe, CdS CIGS and CdS CZTSSe etc) and other optoelectronic devices. We further introduce MoO3 x as a transparent, low barrier back contact. We design nanowire CdS CdTe solar cells on flexible foils of metals in a superstrate device structure, which makes low cost roll to roll manufacturing process feasible and greatly reduces the complexity of fabrication. The MoO3 layer reduces the valence band offset relative to the CdTe, and creates improved cell performance. Annealing as deposited MoO3 in N2 reduces series resistance from 9.98 O/cm to 7.72 O/cm, and hence efficiency of the nanowire solar cell is improved from 9.9% to 11% which efficiency comparable to efficiency of planar counterparts. When the nanowire solar cell is illuminated from MoO3 x /Au side, it yields an efficiency of 8.7% This reduction in efficiency is attributed to decrease in Jsc from 25.5mA/cm 2 to 21mA/cm due to light transmission loss in the MoO3 x /Au electrode. Even though these nanowire solar cells, when illuminated from back side exhibit better performance than that of nanopillar CdS CdTe solar cells, further development of transparent back contacts of CdTe could enable a low cost roll to roll fabrication process for the superstrate structure nanowire solar cells on Al foil substrate.", "author_names": [ "Hongmei Dang" ], "corpus_id": 109470678, "doc_id": "109470678", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Nanostructured Semiconductor Device Design in Solar Cells", "venue": "", "year": 2019 }, { "abstract": "A physics based compact gallium nitride power semiconductor device model is presented in this work, which is the first of its kind. The model derivation is based on the classical drift diffusion model of carrier transport, which expresses the channel current as a function of device threshold voltage and externally applied electric fields. The model is implemented in the Saber(r) circuit simulator using the MAST hardware description language. The model allows the user to extract the parameters from the dc I V and C V characteristics that are also available in the device datasheets. A commercial 80 V EPC GaN HEMT is used to demonstrate the dynamic validation of the model against the transient device characteristics in a double pulse test and a boost converter circuit configuration. The simulated versus measured device characteristics show good agreement and validate the model for power electronics design and applications using the next generation of GaN HEMT devices.", "author_names": [ "Ramchandra M Kotecha", "Yuzhi Zhang", "Arman Ur Rashid", "Nan Zhu", "Tom Vrotsos", "Homer Alan Mantooth" ], "corpus_id": 31414257, "doc_id": "31414257", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "A physics based compact gallium nitride power semiconductor device model for advanced power electronics design", "venue": "2017 IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2017 }, { "abstract": "IEGTs are one of the promising candidates for replacing GTOs in high voltage applications in 4.5 kV range. The injection enhancement effect of IEGT structure with the deep trench MOS gate and/or the wide cell design successfully reduces the voltage drop in the N base. In this paper, we discuss the device physics and design concept of the injection enhancement effect for not only the trench structure but also the planar structure.", "author_names": [ "Ichiro Omura", "Tsuneo Ogura", "Koichi Sugiyama", "H Ohashi" ], "corpus_id": 111056538, "doc_id": "111056538", "n_citations": 49, "n_key_citations": 1, "score": 0, "title": "Carrier injection enhancement effect of high voltage MOS devices device physics and design concept", "venue": "Proceedings of 9th International Symposium on Power Semiconductor Devices and IC's", "year": 1997 }, { "abstract": "In this paper, process, device, and electromagnetic simulations are combined to produce a distributed nonlinear model for an LDMOS RF power transistor. The simulation challenges are handled by using multiple simulators, each with a suitable role in the modeling process. Semiconductor fabrication and device operation are performed through the process and device technology computer aided design (TCAD) tool. The outcome from the TCAD simulations are used to generate a nonlinear compact model for a small section of the device. To form the complete transistor model, many small sections of the compact model are connected by a large scale interconnect network, which is modeled based on electromagnetic (EM) simulations. For convenient use in circuit simulator, the distributed nonlinear model is implemented by a script generated comprehensive netlist. It is demonstrated that this purely simulation based model can accurately predict device behavior under DC, small signal, and large signal tests, and is useful for first pass computer aided design before wafer fabrication.", "author_names": [ "Dan Lamey", "Lei Zhang", "Hernan Rueda", "Humayun Kabir", "Rick Sweeney", "Kevin Kim" ], "corpus_id": 34788806, "doc_id": "34788806", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Device physics and EM simulation based modeling methodology for LDMOS RF power transistors", "venue": "2017 IEEE MTT S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)", "year": 2017 }, { "abstract": "Abstract We introduce a new platform called KdotPsoft, to model and simulate semiconductor quantum wells (QWs) and multiple QW (MQW) systems. It is suitable to design and study quantum cascaded lasers, vertical cavity surface emitting laser, etc in conjunction with experiment and fabrication. For fundamental physics and device physics applications, KdotPsoft is an ideal platform to model, simulate and study semiconductors QWs and MQW structures for fundamental physics and device physics applications. It can study MQW based structures such as quantum cascaded lasers (QCL) vertical cavity surface emitting laser (VCSEL) etc. KdotPsoft is based on the 16 band k*p perturbation theory model and it supports all conventional semiconductor materials, and also can works for dilute nitride and bismide doped semiconductors. As a demonstration, we will show a study an example case of lattice matched GaNBiAs/GaAs QWs and show its major results, such as the energy dispersion curves, optical gain spectra and electron hole wave functions. At a larger scale, it can be used to comprehensively study the band lineups, energy dispersion relation, DOS, polarization dependent transition matrix element strengths, optical gain/absorption spectra, spontaneous emission rate, radiative current density, electric field effects on the QW, etc. Advanced users may note that the development of the platform was done using Fortran and Python. We will strive to make KdotPsoft available as a independent platform or a Matlab toolbox in the future.", "author_names": [ "Sumanta Bose", "Zhigang Song", "Weijun Fan", "Dawei Zhang" ], "corpus_id": 115797720, "doc_id": "115797720", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "KdotPsoft: Modelling and Simulation of Semiconductors and Device Physics", "venue": "", "year": 2017 }, { "abstract": "Abstract As one of the most appealing two dimensional materials, graphene (Gr) has attracted tremendous research interest in optoelectronic device applications for its plenty of exceptional electrical and optical properties. The emergence of Gr/semiconductor hybrid heterostructures provides a promising platform for assembling high performance optoelectronic devices that can overcome intrinsic limitations of Gr. However, although significant achievements have been made, many challenges still exist. Here, we comprehensively review the progress in the development of various optoelectronic devices based on Gr/semiconductor hybrid heterostructures, including /group II VI nanostructures, /group III V semiconductors, /group IV semiconductors, /metal oxides and /other semiconductors, in terms of the device design, device performance and physics, processing techniques for performance optimization, etc. In the final section, conclusions of the existing techniques are presented and future challenges in optoelectronic applications of Gr/semiconductor hybrid heterostructures are addressed.", "author_names": [ "Chao Xie", "Yi Wang", "Zhi-Xiang Zhang", "Di Wang", "Lin-Bao Luo" ], "corpus_id": 139711807, "doc_id": "139711807", "n_citations": 100, "n_key_citations": 0, "score": 0, "title": "Graphene/Semiconductor Hybrid Heterostructures for Optoelectronic Device Applications", "venue": "", "year": 2018 }, { "abstract": "The requirements of high speed and performance and cost effectiveness demand of VLSI chips a continuing push in miniaturization. As a consequence, the design rule (or the effective gate length) has been reduced from several microns down to 0.1 mm envisioned within a few years. While the expected 256 Mb chip requires the use of quarter micron design rules, it is expected that we will need 0.1 0.15 mm rules for gigabit chips, and the extrapolation of the down scaling trends will extend the design rules to sub 0.1 mm for a terabit memory chip in the near future. With this scenario for VLSI technology development, the deep understanding of the device physics governing device operation is the key to successful device design, as different physical mechanism impose different level of effects on different device scales.", "author_names": [ "J Zhou", "David K Ferry" ], "corpus_id": 114232384, "doc_id": "114232384", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "3D Discrete Dopant Effects on Small Semiconductor Device Physics", "venue": "", "year": 1996 }, { "abstract": "Experimental facilities for measuring noise were developed. These included the fabrication of a test station for measuring noise at low frequency <100 kHz) in both high and low impedance devices and at high frequency <18 GHz) These new test stations are being used to study current noise in quantum cascade lasers. In addition to noise measurements under DC operation, a 12 Gb/s bit error rate tester (BERT) was installed and used to test the noise models for surface emitting lasers.", "author_names": [ "Dr Holger Schmidt Rajeev J Ram", "M Abraham", "Harry L T Lee", "Steven Gregory Patterson", "Kevin P Pipe", "", "Mehmet Fatih Yanik", "Margaret Wang" ], "corpus_id": 11303958, "doc_id": "11303958", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Semiconductor Lasers Device Physics and Applications", "venue": "", "year": 2000 } ]

[ { "abstract": "Abstract The net Y, a novel two dimensional carbon allotrope with four six and eight membered rings, is investigated by performing first principles calculations. The calculations on structural stability unambiguously prove that net Y is an energetically metastable, dynamically and thermally stable phase, and it can also be buckled about 0.4 A. We find that the net Y exhibits strong mechanical anisotropy, and the in plane Young's modulus of net Y along a and b directions is found smaller than graphene but comparable with that of ps graphene and penta graphene. Meanwhile, the net Y possesses intrinsic metallicity with high carrier velocities comparable to that of graphene ~106 m/s) Excitedly, a possible synthetic route towards net Y from graphene like nanoribbons embedded four and eight membered rings is achieved by first principles molecular dynamics simulations, indicating that the realization of net Y is not impossible. Moreover, two three dimensional (3D) stable close packed net Y carbon allotropes are also proposed. Unlike the metallic 3D planar net Y, the 3D buckled net Y is a superhard indirect bandgap semiconductor, which further broadens the application potential of net Y.", "author_names": [ "Ju Rong", "Huicong Dong", "Jing Feng", "Xiao Fei Wang", "Yannan Zhang", "Xiaohua Yu", "Zhao-lin Zhan" ], "corpus_id": 103905379, "doc_id": "103905379", "n_citations": 25, "n_key_citations": 0, "score": 1, "title": "Planar metallic carbon allotrope from graphene like nanoribbons", "venue": "", "year": 2018 }, { "abstract": "Recently, a new type of quasi 1D graphene like nanoribbons periodically embedded four and eight membered rings have been successfully fabricated, and based on this structure, a novel planar 2D carbon allotrope, so called the net Y, has been proposed. Here, we study various nanoribbons derived from such a 2D monolayer focusing on the structure stability, electronic and transport properties, especially on the physical field coupling effects of electronic behaviors. The very high stability is predicted for various types of nanoribbons by the calculated binding energy and molecular dynamics simulation. Different edge shape and widths have a significant influence on their electronic properties. Armchair nanoribbons are always semiconductors, and possess a high carrier mobility. After hydrogen termination, some metallic nanoribbons can become semiconductors or quasi metals with massless Dirac fermion behavior. In particular, the electronic properties of ribbons can be effectively modulated by applying strain and electric field. The band gap size and the transition from indirect to direct band gap can be realized upon strain or electric field. These flexibly tunable electronic properties for nanoribbons expand their applications in nanoelectronics and optoelectronics.", "author_names": [ "Jing Min Hu", "Zhenhua Zhang", "Z Q Fan", "R L Zhou" ], "corpus_id": 201098324, "doc_id": "201098324", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Electronic and transport properties and physical field coupling effects for net Y nanoribbons.", "venue": "Nanotechnology", "year": 2019 }, { "abstract": "A two dimensional carbon allotrope, H net, is proposed using first principle calculations. H net incorporates C4 distorted squares, C6 hexagons, and C8 octagons. Unlike previously reported planar graphene and other theoretical carbon sheets, H net is a two atom thick polymorph with identical C6 C4 C6 components cross facing and covalently buckled to feature a handshake like model. The feasibility of H net is evident from its dynamic stability as confirmed by phonon mode analysis and its lower total energy. H net is energetically more favorable than synthesized graphdiyne and theoretical graphyne, BPC, S graphene, polycyclic net, a squarographite, and lithographite. We explored a possible route for the synthesis of H net from graphene nanoribbons. Electronic band structure calculations indicated that H net is a semiconductor with an indirect band gap of 2.11 eV, whereas graphene and many other two dimensional carbon sheets are metallic. We also explored the electronic structure of one dimensional nanoribbons derived from H net. The narrowest H net nanoribbon showed metallic behavior, whereas the other nanoribbons are semiconductors with band gaps that increase as the nanoribbons widen. H net and its tailored nanoribbons are expected to possess more electronic properties than graphene because of their exceptional crystal structure and different energy band gaps.", "author_names": [ "Meng Hu", "Yu Shu", "Lin Cui", "Bo Xu", "Dongli Yu", "Julong He" ], "corpus_id": 37410525, "doc_id": "37410525", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Theoretical two atom thick semiconducting carbon sheet.", "venue": "Physical chemistry chemical physics PCCP", "year": 2014 }, { "abstract": "Abstract A new two dimensional carbon allotrope TPDH graphene (Tetra Penta Deca Hexagonal graphene) belonging to the tetragonal pentagonal carbon ring family is proposed in this work using density functional method. The allotrope satisfies all the conditions of structural stability. This allotrope has lower cohesive energy than many existing planar carbon allotropes. It can withstand temperature as high as 1000 K without loosing its structural integrity. However, its electronic structure reflects metallic character due to delocalised pz orbital near the Fermi level. Further, this mechanically stable elastically anisotropic structure shows directional variation of In plane Young's modulus and Poisson's ratio. It is stronger than graphene in a particular direction. Moreover, The material can be identified by four characteristic peaks in the electron energy loss spectra within 10 eV energy. It has optical reflectance peaks in the visible range at ~600 nm yellow colour. Interestingly, some nanoribbons of this material show semimetallic, semiconducting and metallic behaviour. Non equilibrium Green's function method along with density functional theory is employed to study the nanodevices made of these nanoribbons. Strong current regulation property and robust negative differential resistance effect with a peak to valley ratio 3.3 are observed in two nanodevices making TPDH graphene an attractive material for use in nanoelectronics.", "author_names": [ "Debaprem Bhattacharya", "Debnarayan Jana" ], "corpus_id": 229406802, "doc_id": "229406802", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "TPDH graphene: A new two dimensional metallic carbon with NDR behaviour of its one dimensional derivatives", "venue": "", "year": 2021 }, { "abstract": "Elemental phosphorus nanostructures are notorious for a large number of allotropes, which limits their usefulness as semiconductors. To limit this structural diversity, we synthesize selectively quasi 1D phosphorus nanostructures inside carbon nanotubes (CNTs) that act both as stable templates and nanoreactors. Whereas zigzag phosphorus nanoribbons form preferably in CNTs with an inner diameter exceeding 1.4 nm, a previously unknown square columnar structure of phosphorus is observed to form inside narrower nanotubes. Our findings are supported by electron microscopy and Raman spectroscopy observations as well as ab initio density functional theory calculations. Our computational results suggest that square columnar structures form preferably in CNTs with inner diameter around 1.0 nm, whereas black phosphorus nanoribbons form preferably inside CNTs with 4.1 nm inner diameter, with zigzag nanoribbons energetically favored over armchair nanoribbons. Our theoretical predictions agree with the experimental findings.", "author_names": [ "Jinying Zhang", "Chengcheng Fu", "Shixin Song", "Hongchu Du", "Dan Zhao", "Hongyang Huang", "Lihui Zhang", "Jie Guan", "Yifan Zhang", "Xinluo Zhao", "Chuansheng Ma", "Chun-Lin Jia", "David Tomanek" ], "corpus_id": 210043500, "doc_id": "210043500", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Changing the Phosphorus Allotrope from a Square Columnar Structure to a Planar Zigzag Nanoribbon by Increasing the Diameter of Carbon Nanotube Nanoreactors.", "venue": "Nano letters", "year": 2020 }, { "abstract": "A novel two dimensional carbon allotrope, rectangular graphyne (R graphyne) with tetra rings and acetylenic linkages, is proposed by first principles calculations. Although the bulk R graphyne exhibits metallic property, the nanoribbons of R graphyne show distinct electronic structures from the bulk. The most intriguing feature is that band gaps of R graphene nanoribbons oscillate between semiconductor and metal as a function of width. Particularly, the zigzag edge nanoribbons with half integer repeating unit cell exhibits unexpected Dirac like fermions in the band structures. The Dirac like fermions of the R graphyne nanoribbons originate from the central symmetry and two sub lattices. The extraordinary properties of R graphene nanoribbons greatly expand our understanding on the origin of Dirac like point. Such findings uncover a novel fascinating property of nanoribbons, which may have broad potential applications for carbon based nano size electronic devices.", "author_names": [ "Wen-Jin Yin", "Yuee Xie", "Li-Min Liu", "Ruzhi Wang", "Leo W M Lau", "Jianxin Zhong", "Yuan-Ping Chen" ], "corpus_id": 119284834, "doc_id": "119284834", "n_citations": 80, "n_key_citations": 0, "score": 0, "title": "R graphyne: a new two dimension carbon allotrope with versatile Dirac like point in nanoribbons", "venue": "", "year": 2013 }, { "abstract": "Abstract By means of the first principles calculations, we have theoretically investigated the structural stability and electronic properties of a two dimensional planar metallic carbon allotrope named C 57 carbon which possesses the P 6 2 m D 3 h 3 symmetry. This carbon allotrope is an all sp 2 hybridized bonding network consisting of 5 7 rings of carbon atoms. The stability of C 57 carbon is confirmed through phonon mode analysis, total energy and elastic constants calculations, as well as first principles molecular dynamics simulations. We conceived that the metallicity of C 57 carbon is attributed to the large states across Fermi level contributed by p y orbital due to the bond distortion, which is much different from that of graphite. This new carbon sheet can also serve as a precursor for stable one dimensional nanotubes with metallic character. These results broaden our understanding of two dimensional carbon allotropes and will attract more researchers to focus the research on the field of two dimensional carbon materials. Besides, the C 57 carbon may be useful for designing of nano electronic devices.", "author_names": [ "Chunxiang Zhao", "Yi-Qi Yang", "Chunyao Niu", "Jia-Qi Wang", "Yu Jia" ], "corpus_id": 139558128, "doc_id": "139558128", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "C 57 carbon: A two dimensional metallic carbon allotrope with pentagonal and heptagonal rings", "venue": "Computational Materials Science", "year": 2019 }, { "abstract": "Two dimensional (2D) carbon allotropes have attracted great attention in both science and engineering fields. Their extraordinary and/or unique properties make them promising for engineering applications, ranging from metal ion batteries to biosensors. Herein, by employing first principles calculations, we propose a new 2D planar carbon allotrope, popgraphene, which is composed of 5 8 5 carbon rings. Using a bottom up approach, popgraphene could be constructed via the formation of atomically precise 5 8 5 line defects in graphene by simultaneous electron irradiation. Popgraphene is intrinsically metallic. It has low energy and possesses great dynamic, thermal and mechanical stability. Our calculations also show that it has a high theoretical capacity for Li atoms (Li4C6: 1487 mA h g 1) a low Li diffusion barrier <0.55 eV) and a low average open circuit voltage (0.45 V) Such excellent characteristics suggest that programmable metallic popgraphene is a promising anode material for use in Li ion batteries (LIBs) with fast charge/discharge rates. Our simulation results also indicate that van der Waals corrections play little role in the structural parameters of popgraphene, whereas they play a central role in the adsorption and diffusion abilities as well as the electrochemical performance of popgraphene. This study provides fundamental insight into the design of new materials with extraordinary properties for their excellent applications, including for the next generation of LIBs, and may open up a cutting edge field in programming experimentally realized low dimensional materials.", "author_names": [ "Shuaiwei Wang", "Bao-cheng Yang", "Houyang Chen", "Eli Ruckenstein" ], "corpus_id": 102624752, "doc_id": "102624752", "n_citations": 128, "n_key_citations": 2, "score": 0, "title": "Popgraphene: a new 2D planar carbon allotrope composed of 5 8 5 carbon rings for high performance lithium ion battery anodes from bottom up programming", "venue": "", "year": 2018 }, { "abstract": "Carbon materials based on different hybridization of carbon atoms have drawn great attention because of their unique configurations and physical and chemical properties. Here, a previously unknown 2D carbon allotrope named L 2Gy, graphene like carbon matryoshka graphynes (Gy) with two alkynyls (C[triple bond, length as m dash]C) inserted into the three fold carbon atoms of graphene, has been constructed with considerable thermal, dynamical, and mechanical stability by using ab initio density functional theory. With the increasing number of alkynyls between the three fold carbon atoms of graphene, the stability of Gy will seriously decrease. L 2Gy has a fascinating chemical bond environment consisting of sp and sp2 hybridized carbon atoms, and delocalized p electrons derived from the 27 three center two electron p bonds. This particular electronic structure plays a vital role in chemically stabilizing L 2Gy. The electronic band structure reveals the semi metallic features of L 2Gy mainly contributed by the px/z orbitals of carbon atoms. Furthermore, compared with the acknowledged catalysts for the hydrogen evolution reaction (HER) L 2Gy, as a 2D carbon allotrope, shows excellent catalytic activity for the HER.", "author_names": [ "Yaoxiao Zhao", "Zhibin Gao", "Kun Yuan", "Xiang Zhao" ], "corpus_id": 234746610, "doc_id": "234746610", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Theoretically modelling graphene like carbon matryoshka with strong stability and particular three center two electron p bonds.", "venue": "Physical chemistry chemical physics PCCP", "year": 2021 }, { "abstract": "Abstract A two dimensional (2D) metallic carbon allotrope is proposed, which consists of linearly aligned bipentagon octagon and hexagon rings in a planar sheet. The relatively high percentage of hexagon and the regular arrangement of the polygons make it energetically more favorable than most of other predicted 2D carbon allotropes. Phonon dispersions without negative frequencies also indicate its stability. Electronic structure calculations show that its metallic nature is mainly due to the atoms shared by the pentagon, hexagon and octagon. Its lattice thermal conductivity is only about one fifth of that of graphene. Armchair and zigzag edged nanoribbons of this structure are also studied. The former is metallic while the latter has a small band gap due to the spin polarized edge states. The appropriate band gap and the significantly reduced thermal conductivity suggest potential applications in thermoelectricity.", "author_names": [ "Guo-hui Zheng", "Yalei Jia", "Song Gao", "San-huang Ke" ], "corpus_id": 125656830, "doc_id": "125656830", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "A planar carbon allotrope with linear bipentagon octagon and hexagon arrangement", "venue": "", "year": 2017 } ]

[ { "abstract": "The performance of the gate drive power supply (GDPS) greatly impacts the safety and reliability of the gate drive for power semiconductor power devices. This paper focuses on the design of isolated gate driver power supply for 10 kV silicon carbide (SiC) MOSFET for medium voltage (MV) applications. Different insulation schemes are compared for the high voltage insulated transformer in GDPS. Impact factors for transformer interwinding capacitance are analyzed, with which, a low inter winding capacitance design approach is proposed for the high voltage insulated transformer. Furthermore, an upward voltage reference based voltage regulation scheme is proposed for achieving good load regulation without output voltage feedback. Finally, a 20 kV insulated GDPS is built and tested, and experimental results are presented to verify the effectiveness of the design approach.", "author_names": [ "Li Sha Zhang", "Shiqi Ji", "Shida Gu", "Xingxuan Huang", "James Palmer", "William Giewont", "Fred Wang", "Leon M Tolbert" ], "corpus_id": 169033927, "doc_id": "169033927", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "Design Considerations of High Voltage Insulated Gate Drive Power Supply for 10 kV SiC MOSFET in Medium Voltage Application", "venue": "2019 IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2019 }, { "abstract": "SiC MOSFETs have demonstrated continued performance improvement and maturation in the areas of Gate oxide stability and reliability over the past years. While necessary, this alone is not sufficient to achieve reliable high voltage operation. In this paper, the design constraints impacting high voltage reliability and their impact on SiC MOSFET performance at useful operating conditions are discussed. Experimental results are demonstrated with industry benchmark, reliable operation of up to Tj=200degC with 1.2kV/25mOhm SiC MOSFETs and Tj=175degC, 1.7kV/450A all SiC MOSFET Dual Switch modules. Avalanche ruggedness of the high performance devices is also demonstrated with single pulse energy densities of 9 15J/cm2 recorded with Drain currents as high as ID= 90A for 0.2cm2 die.", "author_names": [ "Peter Almern Losee", "Alexander Viktorovich Bolotnikov", "L Yu", "Greg Dunne", "David Richard Esler", "Jeffrey Erlbaum", "Brian Lynn Rowden", "Arun Virupaksha Gowda", "Adam F Halverson", "Reza Ghandi", "Peter M Sandvik", "Ljubisa Dragoljub Stevanovic", "R Hristov" ], "corpus_id": 42686707, "doc_id": "42686707", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "SiC MOSFET design considerations for reliable high voltage operation", "venue": "2017 IEEE International Reliability Physics Symposium (IRPS)", "year": 2017 }, { "abstract": "The 10 kV to 15 kV SiC MOSFET and 15 kV SiC IGBT are state of the art high voltage (HV) devices designed by Cree Inc. These devices are expected to increase the power density of converters and are expected to replace 4.5 kV/6.5 kV Si IGBTs. However, these are not commercially available. On the other hand low voltage (LV) 1.7 kV SiC MOSFET is commercially available, and it is replacing existing 1.7 kV Si IGBT and it can meet immediate need of medium or high voltage (MV or HV) converter applications with series connection of these devices and can replace existing 4.5 kV/6.5 kV Silicon (Si) IGBT. Therefore, 10 kV 15 kV SiC modules and series connected 1.7 kV SiC MOSFET will be competing with each other for MV and HV converter applications. Hence, to explore the capability of low voltage SiC devices for MV or HV applications, a HV switch (10 kV 15 kV) using the series connection of 1.7 kV/300 A SiC MOSFET modules has been investigated. For making HV switch using series connected 1.7 kV SiC MOSFET, a simple RC snubber method has been used for dynamic voltage sharing to offset the turn off delays due to mismatch of device characteristics and gate signals. Experimental switching characterization with different values of RC snubbers has been carried out, and a methodology has been outlined to find the optimal RC snubber which gives minimum voltage sharing difference, snubber losses and total semiconductor losses. In addition, experimental switching characterization of 10 kV 15 kV SiC modules is presented. Furthermore, a performance comparison of HV 10 kV 15 kV SiC modules and HV switch using series connected 1.7 kV SiC MOSFETs is presented in this paper.", "author_names": [ "Kasunaidu Vechalapu", "Subhashish Bhattacharya" ], "corpus_id": 7401760, "doc_id": "7401760", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Performance comparison of 10 kV#x2013;15 kV high voltage SiC modules and high voltage switch using series connected 1.7 kV LV SiC MOSFET devices", "venue": "2016 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2016 }, { "abstract": "This paper addresses a study of output voltage of a switched capacitor step down converter for a high voltage application. The proposed design is 3:4 Series to parallel switched capacitor converter based on capacitors and switches only. The Slow Switching Limit Impedance was theoretically calculated and proven. The Slow Switching Limit Impedance has an inverse relation with switching frequency and the capacitor's size. A minimum value of the Slow Switching Limit Impedance is desired; however, that requires a high switching frequency. Increasing the switching frequency might produce losses from switching devices. To maintain the output voltage by keeping switching losses low, a wide bandgap silicon carbide SiC MOSFET was used in this work. The output voltage and its ripple were tested and compared when ideal switches or SiC MOSFET was used. The comparison between ideal switches and SiC MOSFET was applied under several values of the switching frequency. When the fsw increases, a SiC MOSFET successfully shows its ability to keep the switching losses suitable. The LTspice software have been used to simulate the proposed switched capacitor, and the results have been analyzed and discussed.", "author_names": [ "Ayoob Alateeq", "Yasser Almalaq", "Mohammad A Matin" ], "corpus_id": 8842824, "doc_id": "8842824", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Using SiC MOSFET in switched capacitor converter for high voltage applications", "venue": "2016 North American Power Symposium (NAPS)", "year": 2016 }, { "abstract": "The paper aims at clarifying the carrier trapping influence on the electrical characteristics of silicon carbide (SiC) power MOSFETs and its inclusion in the simulation of SiC power mosfet based circuits. Special focus is given on the degradation of the switching characteristics due to carrier trapping at SiC/SiO2 interface defects. A compact SiC power mosfet model, considering the trap density in the framework of a complete surface potential description, has been developed by for accurate circuit simulation including power loss prediction. The carrier trapping is verified to cause a switching delay, which results in switching loss increase. To achieve low power loss, trap density reduction is shown to be vital. The maximum allowable trap density, which does not affect switching power loss, is discussed.", "author_names": [ "Yuta Tanimoto", "Atsushi Saito", "Kai Matsuura", "Hideyuki Kikuchihara", "Hans Jurgen Mattausch", "Mitiko Miura-Mattausch", "Noriaki Kawamoto" ], "corpus_id": 13436960, "doc_id": "13436960", "n_citations": 38, "n_key_citations": 2, "score": 0, "title": "Power Loss Prediction of High Voltage SiC mosfet Circuits With Compact Model Including Carrier Trap Influences", "venue": "IEEE Transactions on Power Electronics", "year": 2016 }, { "abstract": "Newly developed 15 kV silicon carbide (SiC) power MOSFETs with fast switching capability enable the reduction of size, weight and complexity of medium voltage power converters. In medium voltage and high frequency applications, zero voltage switching (ZVS) is necessary since significant amount of energy is stored in MOSFETs' parasitic output capacitors. Recovering these energy is important for high conversion efficiency while ZVS also reduces the dV/dt significantly in these devices. To guarantee complete ZVS, it is crucial to accurately characterize the output charge of devices. In this paper, existing high voltage capacitance and output charge measurement techniques are reviewed. A dynamic half bridge test method for 15kV SiC MOSFETs' output charge measurement is thoroughly analyzed and experimentally verified up to 6 kV. Output capacitance model is then derived using the measured results. The test circuit not only reflects the realistic ZVS scenario, but also achieves high accuracy <1% error) without resorting to special equipment or complex configuration which are usually necessary in high voltage test. System level design consideration, error analysis and accuracy certification for this high voltage tester is also given in the paper.", "author_names": [ "Li Wang", "Qianlai Zhu", "Wensong Yu", "Alex Q Huang" ], "corpus_id": 24033978, "doc_id": "24033978", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "A study of dynamic high voltage output charge measurement for 15 kV SiC MOSFET", "venue": "2016 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2016 }, { "abstract": "Silicon Carbide (SiC) MOSFETs are being increasingly utilized in medium and high power electronics converters >1 kW) because of the significantly lower switching and conduction losses when compared with conventional power switches such as the Si IGBT. SiC MOSFET based converters operating at high frequency can achieve high efficiency and high power density at the same time. Minimum switching loss can be achieved in the SiC MOSFET with carefully designed gate driving condition and DC link layout, such as the integrated SiC MOSFET module discussed in this paper. Multi megahertz switching frequency could be realized by the proposed SiC MOSFET module with proper soft switching topology. This paper analyzes three isolated DC/DC converters, namely the asymmetrical half bridge converter, phase shift full bridge converter, and LLC resonant converter. The loss model of the SiC MOSFET is developed and utilized in the analysis. Comparisons are carried out from the device loss and soft switching requirement point of view. The LLC resonant converter is deemed more suitable for multi megahertz application. A 4.5 kW 1.2 MHz LLC resonant converter prototype is developed and it demonstrates a peak efficiency of 97% at 4 kW.", "author_names": [ "Suxuan Guo", "Pengkun Liu", "Ruiyang Yu", "Liqi Zhang", "Alex Q Huang" ], "corpus_id": 14803280, "doc_id": "14803280", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Analysis and loss comparison of megahertz high voltage isolated DC/DC converters utilizing integrated SiC MOSFET module", "venue": "2016 IEEE 4th Workshop on Wide Bandgap Power Devices and Applications (WiPDA)", "year": 2016 }, { "abstract": "Recent studies have pointed out the benefits of using Silicon Carbide (SiC) devices in photo voltaic power conversion. In Particular, SiC Power MOSFET technology has greatly advanced over the last years and has presently reached sufficient maturity to stimulate a concrete interest in the development of power conversion circuits based entirely on this technology, in view of the clear potential advantages it offers over alternative SiC device technologies (e.g. JFET, BJT) This paper presents a thorough characterization of an all SiC MOSFET based single phase bi directional switched neutral point clamped (BSNPC) three level inverter, in which, for the first time, SiC Power MOSFETs of different voltage ratings (1200 and 600V) are used. A parametric experimental characterization of the power cell performance is carried out, separating the effects of output power, heat sink temperature and switching frequency and load variations by means of bespoke heat sink design. The effect of relying exclusively on the MOSFET body diode for inductive load current freewheeling is critically assessed against usage of an external SiC Schottky diode. The experimental results are compared with a mixed approach design, where Silicon (Si) devices are used for the lower voltage switches and SiC MOSFETs are kept for the higher voltage ones, deriving a clear indication of the superior possibilities offered by SiC Power MOSFETs for improved efficiency, power density and reliability, key aspects of power electronics technology evolution.", "author_names": [ "Dipankar De", "Alberto Castellazzi", "Adane Kassa Solomon", "Andrew Trentin", "Masataka Minami", "Takashi Hikihara" ], "corpus_id": 18946116, "doc_id": "18946116", "n_citations": 35, "n_key_citations": 1, "score": 0, "title": "An all SiC MOSFET high performance PV converter cell", "venue": "2013 15th European Conference on Power Electronics and Applications (EPE)", "year": 2013 }, { "abstract": "", "author_names": [ "Vechalapu Kasunaidu", "Bhattacharya Subhashish" ], "corpus_id": 117273198, "doc_id": "117273198", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Performance comparison of 10 kV#x2013;15 kV high voltage SiC modules and high voltage switch using series connected 1.7 kV LV SiC MOSFET devices", "venue": "", "year": 2016 }, { "abstract": "The medium voltage (MV) high speed drives are required for traction, wind energy, marine, aerospace, oil, and gas compressors applications. The MV converter must be able to switch at higher switching frequencies 5 kHz) to generate higher fundamental frequency AC input voltages for the motor 500 Hz) and thereby achieving high speed at the motor output 15000 rpm) This paper presents the series connection of 1.7 kV SiC MOSFET devices to enable simple two level MV converter for high speed drive and grid connected applications. Experimental switching characterization of a phase leg (one pole of a three phase converter) with the series connection of four devices per arm (or eight per leg) has been presented. It also presents the experimental results of a DC AC half bridge inverter with four devices in series per arm at 3kV dc bus, at different fundamental frequencies. It also includes the experimental endurance test results of phase leg (pole) in a DC DC converter at 100 kW, 3kV dc bus. Furthermore, it also presents the performance evaluation of a 3 phase voltage source inverter (VSI) efficiency using four series connected devices for 3.6 kV dc bus, 2.1 kV AC(L L) 720 kW output power and its comparison with single 6.5 kV Si IGBT.", "author_names": [ "Kasunaidu Vechalapu", "Samir Hazra", "Utkarsh Raheja", "Abhay Negi", "Subhashish Bhattacharya" ], "corpus_id": 34945276, "doc_id": "34945276", "n_citations": 18, "n_key_citations": 2, "score": 0, "title": "High speed medium voltage (MV) drive applications enabled by series connection of 1.7 kV SiC MOSFET devices", "venue": "2017 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2017 } ]

[ { "abstract": "The trend in isolated DC/DC converters is increasing output power demands and higher operating frequencies. Improved topologies and semiconductors can allow for lower loss at higher frequencies. A major barrier to further improvement is the transformer design. With high current levels and high frequency effects the transformers can become the major loss component in the circuit. High values of transformer leakage inductance can also greatly degrade the performance of the converter. Matrix transformers offer the ability to reduce winding loss and leakage inductance. This paper will study the impact of increased switching frequencies on transformer size and explore the use of matrix transformers in high current high frequency isolated applications. This paper will also propose an improved integrated matrix transformer design that can decrease core loss and further improve the performance of matrix transformers.", "author_names": [ "David Reusch", "Fred C Lee" ], "corpus_id": 9387185, "doc_id": "9387185", "n_citations": 57, "n_key_citations": 3, "score": 1, "title": "High frequency bus converter with low loss integrated matrix transformer", "venue": "2012 Twenty Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2012 }, { "abstract": "In this article, an LLC converter using gallium nitride (GaN) transistors is proposed for a 48 V regulated and isolated bus converter. Compared with pulsewidth modulation (PWM) based topologies, the soft switching capability of an LLC allows operation at very high frequencies. In addition, the size of the magnetic components is reduced without sacrificing the efficiency. In this article, a novel magnetic structure that integrates a matrix transformer and inductor with minimum winding and a single magnetic core is proposed, to allow a high density and high efficiency LLC converter design for a bus converter. A 40 60 V input and regulated 12 V output converter is developed to deliver a 1 kW output power in a quarter brick form factor. The designed converter can achieve a power density of 700 W/in3 with a maximum efficiency of 97.82% at half load, dropping to 97.7% at full load operation.", "author_names": [ "Mohamed Hassan Ahmed", "Ahmed Nabih", "Fred C Lee", "Qiang Li" ], "corpus_id": 210247468, "doc_id": "210247468", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Low Loss Integrated Inductor and Transformer Structure and Application in Regulated LLC Converter for 48 V Bus Converter", "venue": "IEEE Journal of Emerging and Selected Topics in Power Electronics", "year": 2020 }, { "abstract": "The trend in intermediate bus architectures is increasing output power demands and higher operating frequencies. Improved topologies and semiconductors can allow for lower loss at higher frequencies. A major barrier to further improvement is the transformer design. With high current levels and high frequency effects the transformers can become the major loss component in the circuit. High values of transformer leakage inductance can also greatly degrade the performance of the converter. Matrix transformers offer the ability to reduce winding loss and leakage inductance. This paper will study the use of matrix transformers for a 600 W, 12 V/50A bus converter and identify the optimal number of matrix transformers. This paper will also propose an improved integrated matrix transformer design that can decrease core loss and further improve the performance of matrix transformers.", "author_names": [ "David Reusch", "Fred C Lee" ], "corpus_id": 25068682, "doc_id": "25068682", "n_citations": 28, "n_key_citations": 2, "score": 0, "title": "High frequency bus converter with integrated matrix transformers for CPU and telecommunications applications", "venue": "2010 IEEE Energy Conversion Congress and Exposition", "year": 2010 }, { "abstract": "A DC DC converter is an essential component in Hybrid Electric Vehicle (HEV) to achieve power transfer from High Voltage bus (HV) to Low Voltage bus (LV) and vice versa. Very high current on the LV side of the high power DC DC converter in a heavy duty hybrid vehicle makes its design extremely challenging. Dual Active Bridge with an integrated matrix planar transformer is considered due to its advantages over other existing topologies, such as the ability to handle very high current on the LV side, bi directional power flow, high power density, zero voltage switching capability, and high modularity. An integrated planar Matrix transformer is chosen for galvanic isolation, as it helps in handling very high current on the LV side efficiently. Multi Objective Design Optimization, with low converter loss and low converter volume as its objectives, is used as a basis of parameters and components design. Current mode control is implemented to achieve a fast response and avoid transformer saturation due to the DC flux injection during the transients. The design algorithm and control scheme has been experimentally verified.", "author_names": [ "Shubham Mungekar", "Akash Dey", "Ghanshyamsinh Gohil" ], "corpus_id": 226293345, "doc_id": "226293345", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High Efficiency Bidirectional DC DC Converter with Matrix Transformer for Heavy Duty Hybrid Electric Vehicles", "venue": "2020 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2020 }, { "abstract": "The trend in isolated DC/DC converters is increasing output power demands and higher operating frequencies. Improved topologies combined with gallium nitride (GaN) transistors can allow for lower loss at higher frequencies. A major barrier to further improvement is the transformer design. With high current levels and high frequency effects the transformers can become the major loss component in the circuit. This paper will study the impact of increased switching frequencies on transformer size, the ability of GaN transistors to increase switching frequency in high frequency resonant topologies, and propose an improved integrated transformer design that can decrease core loss and further improve the performance of traditional matrix transformers. The final demonstration being a Vin=48V, Vo=12V, Io=30A, 1.6MHz GaN converter with an improved integrated transformer offering a power density of 900W/in3.", "author_names": [ "David Reusch", "Fred C Lee" ], "corpus_id": 24742272, "doc_id": "24742272", "n_citations": 25, "n_key_citations": 1, "score": 0, "title": "High frequency isolated bus converter with gallium nitride transistors and integrated transformer", "venue": "2012 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2012 }, { "abstract": "In a global and growing society, it is necessary to rethink strategies in order to minimize the environmental impact resulting from the progressive increase of energy consumption and the misuse of energy resources. Energy power system converters must be considered as a global way to spare most of the wasted energy. Today, in the power distribution infrastructure, including modern residential buildings, most equipment have power supplies with imbedded AC DC power converters which may have overall losses as high as 25% regarding the equipment output. Therefore, common DC buses for residential applications are being studied to increase equipment efficiency. This paper presents and designs an AC DC isolated converter that uses a full bridge matrix topology with high frequency isolation transformer and non electrolytic capacitors to integrate into the future residential buildings DC bus, presenting a reliable alternative to AC power. Non linear control techniques (sliding mode control and backstepping control) are employed to guarantee stability and disturbance robustness to the output DC low voltage, while enforcing sinusoidal input AC current and power factor correction. Control strategies are described and simulation results are presented and discussed.", "author_names": [ "Nelson Santos", "J Fernando Silva", "Vasco Soares" ], "corpus_id": 5090710, "doc_id": "5090710", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "High Frequency Transformer Isolated AC DC Converter for Resilient Low Voltage DC Residential Grids", "venue": "DoCEIS", "year": 2018 }, { "abstract": "Both server and telecom power supply prefers LLC resonant converter with matrix transformer as DC/DC stage due to its high efficiency and high power density. With reduced labor intensive and lower profile, print circuit board (PCB) winding based matrix transformer is gaining more and more attention. A 4 layer PCB structure, with two layers for secondary side winding and another two layers for primary side winding, is general practice. In the case with even number of turns in primary side, each layer has half of the turns. However, with odd number of turns in primary side, it is impossible to physically get half of one turn. This paper proposes a novel winding structure that allows odd number of turns arranged in two layer PCB. Besides, four elemental transformers are integrated into a single planar magnetic core by flux cancellation. The winding width and core dimension are optimized to achieve lower loss and footprint. A 3 kW matrix transformer with 4 layer PCB winding is built up. Turns ratio of 3:1 is demonstrated as an example in each elemental transformer. The proposed winding layout method has simple structure, but shows low winding loss and good current sharing. The matrix transformer is demonstrated on a 500 kHz switching frequency wide band gap device based LLC resonant converter. The prototype achieves a peak efficiency of almost 98.5% and a power density of 24.4 kW/L (400 W/in3)", "author_names": [ "Shuo Wang", "Hongfei Wu", "Fred C Lee", "Qiang Li" ], "corpus_id": 208633070, "doc_id": "208633070", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Integrated Matrix Transformer with Optimized PCB Winding for High Efficiency High Power Density LLC Resonant Converter", "venue": "2019 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2019 }, { "abstract": "In this paper, a high efficiency and power density unregulated LLC converter (DCX) is proposed for a first stage converter in two stages 48V voltage regulator module (VRM) for data center applications. An optimized matrix transformer structure including an enhanced termination method for both primary and secondary side winding, in addition, a PCB winding structure for equal current sharing among all transformer parallel layers is proposed, by which a significant reduction in the total conduction loss for the high frequency transformer is achieved. The proposed optimized design is applied for designing two LLC DCX converters with different fixed transformation ratios of (4:1) and (8:1) to study and evaluate the impact of the intermediate bus voltage variation on the overall two stage 48V VRM performance. The designed LLC DCX with GaN devices can provide a continuous output power of 900W with maximum efficiencies of 98.4% for the (4:1) conversion and 98.0% for the (8:1) conversion with high power densities of 1600 W/in3 and 1200W/in3 respectively.", "author_names": [ "Mohamed Hassan Ahmed", "Fred C Lee", "Qiang Li", "Michael A de Rooij" ], "corpus_id": 208630750, "doc_id": "208630750", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Design Optimization of Unregulated LLC Converter with Integrated Magnetics for Two Stage 48V VRM", "venue": "2019 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2019 }, { "abstract": "Efficient dc dc power conversion with wide span voltage regulation is crucial to a sustainable and robust power electronics system. Dual active bridge (DAB) offers straight forward regulation and its transformer enables voltage step up/down required for many applications, such as battery chargers and bus converters for dc distribution systems. However, losing soft switching at light loads or when operating at voltage gains far from the turns ratio severely degrades the efficiency of DAB, especially at high switching frequencies. In this article, we demonstrate an enhanced DAB (E DAB) topology which employs an adjustable tap transformer to extend the soft switching over wider voltage gains and increase the power transfer capability. By a proper tap adjustment and with single phase shift modulation, the proposed gallium nitride (GaN) based converter achieved a peak efficiency of 97.4% with an overall efficiency greater than a conventional DAB for voltage gains of up to 2.8 times higher. Employing a quasi planar matrix transformer with integrated leakage inductance at 300 kHz allowed for an extremely high power density of 10 kW/l (7.5 kW/l with cooling) The tapped transformer did not incur extra losses to the topology. The gain versus power transfer characteristic for soft switching operation was derived for the E DAB and its improvement in efficiency was experimentally verified over a wide power range.", "author_names": [ "Armin Jafari", "Mohammad Samizadeh Nikoo", "Furkan Karakaya", "Elison Matioli" ], "corpus_id": 209508085, "doc_id": "209508085", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Enhanced DAB for Efficiency Preservation Using Adjustable Tap High Frequency Transformer", "venue": "IEEE Transactions on Power Electronics", "year": 2020 }, { "abstract": "A switch mode power supply (SMPS) provides a much more efficient solution to drive the DC power supplies. As the LED driver, SMPS have to get the high efficiency, stability, no hot Spot and high current driving ability. Especially, high brightness LEDs is prominent source of light and has better efficiency and reliability than conventional light sources. Transformer is the major challenge and bottleneck for achieving low profile, high power density converter. Conventional transformers are designed with multiple windings on a ingle core. These winding cause higher leakage inductance, more noises and higher losses. Instead of using multiple windings on a single core, matrix transformer uses a single winding on multiple cores, resulting in a modular structure with many inherent advantages. The secondary winding in a matrix transformer consists of a pair of copper plates that are bonded to the inside surface of square ferrite core. In the present study, the design and analysis of matrix transformer converter for the LED driver which is proposed to reduce volume and easy structure, high current density, and high efficiency of the transformer in 300W SMPS. In this study DS DC converter, matrix transformer is integrated into advanced power conversion application systems. The half bridge converter topology is applied to archive object of the system. We designed and examined 300W DC DC converter to verify the performance of the matrix transformer. As a result, its leakage inductance is highly decreased and it is more suitable for high frequency operation than conventional SMPS.", "author_names": [ "Byeong-ho Jeong", "Gil Mo Seo", "Eun-A Moon", "Geum-Bae Cho" ], "corpus_id": 141344669, "doc_id": "141344669", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Study on High Frequency Matrix Transformer Applied to SMPS Design", "venue": "", "year": 2012 } ]

[ { "abstract": "The development of wide band gap semiconductor devices is rapidly promoting the development of power electronics technology, especially in high frequency (HF) power converter region. A category of HF power converter is switch mode power amplifier (PA) This paper focuses on the implementation of a multiphase dc dc PA with high bandwidth and high power rate. When naturally sampled phase shifted carrier modulation is implemented in the practical digital control system to control this HF power converter, the pulsewidth error problem caused by limited domain frequency of control chip becomes much severer. As a result, dc voltage component of each phase becomes different under several conditions, leading to current imbalance among phase inductors. This paper analyzes this problem and proposes a sensorless control method to solve it, based on the injection of random sequence in reference wave. A four phase prototype employing GaN devices is fabricated, switching at 1 MHz. Current imbalance and effectiveness of the proposed control method are verified by experimental results. The prototype is capable of uniformly amplifying sine signal within 200 kHz and a 350 kHz bandwidth random signal, with peak output power up to 810 W.", "author_names": [ "Chao Wang", "Kui Wang", "Zedong Zheng", "Kai Sun", "Yongdong Li" ], "corpus_id": 149748031, "doc_id": "149748031", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Modulation Induced Current Imbalance and Its Sensorless Control of a GaN Based Four Phase DC DC Power Amplifier", "venue": "IEEE Transactions on Industrial Electronics", "year": 2020 }, { "abstract": "In this paper a DC DC power converter design suitable for high frequency applications by using class E power amplifier (Inverter) instead of using small battery values choosing radio frequency(RF) values and getting high efficiency of output voltage and maximum of current and voltage values between 0 9 mW of power input in rectifier, the class E power amplifier designed by using GaN HEMT device and the power added efficiency of 64% after getting optimization of matching network and the gain is 14.4 dBm.", "author_names": [ "Sriram Muthukumar", "M C John Wiselin", "Durai Kanchana", "Balakrishnapillai Suseela Sreeja" ], "corpus_id": 209168526, "doc_id": "209168526", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Design of DC DC Power Converter Using Power Amplifier", "venue": "", "year": 2020 }, { "abstract": "This paper presents the use of envelope tracking in class D digital audio amplifiers supplied through step up DC DC converters as applied in automotive, battery operated, and portable devices. It is shown that envelope tracking offers significant improvements in efficiency of up to 26% for the class D stage of a 100 W amplifier in a typical usage scenario, with a corresponding overall system improvement of up to 27% including a boost converter. Detailed simulation results of the complete system are presented, as well as experimental results performed on an existing 100 W class D amplifier design. Efficiency versus power results are combined with music power distribution profiles to simulate typical usage cases. Challenges relating to envelope tracking and DC DC converter control are discussed. It is concluded that there is significant potential for envelope tracking to provide improvement over the standard fixed supply amplifier design especially at low power, where the amplifier is normally used most.", "author_names": [ "Robert Bakker", "Maeve Duffy" ], "corpus_id": 5019604, "doc_id": "5019604", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Improving the efficiency of class D audio amplifier systems using envelope tracking DC DC power supplies", "venue": "2018 IEEE Applied Power Electronics Conference and Exposition (APEC)", "year": 2018 }, { "abstract": "A commercial off the shelf GSM PA powered directly from a DC DC converter is presented. The converter is implemented in 0.35 mm CMOS and employs frequency hopping with phase chopping to eliminate spurious noise. Measurement results demonstrate elimination of spurs, allowing an incompliant GSM PA that is violating the limits of the GSM spectral mask by 9.3 dB to be brought back to compliance without additional filtering or linear regulation between the converter and the PA.", "author_names": [ "Chengwu Tao", "Ayman A Fayed" ], "corpus_id": 28759928, "doc_id": "28759928", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "A GSM Power Amplifier Directly Powered From a DC DC Power Converter", "venue": "IEEE Microwave and Wireless Components Letters", "year": 2012 }, { "abstract": "This paper presents a power amplifier (PA) based on a boosted supply voltage using a boost DC DC converter to eliminate the load impedance matching network for handset applications. With appropriate transistor size and boosted collector/drain voltage, the optimum load impedance of the PA can be around 50 O to have a required output power level. As a result, loss and bandwidth limitation from the output matching network can be greatly mitigated. In addition, efficiency improvement at low output power level can be obtained by decreasing the output voltage of the boost DC DC converter, which is an average power tracking (APT) operation. To prove the proposed concept, the PA with a boost DC DC converter was implemented for the 1.88 GHz band. Using a 16 QAM uplink LTE signal with a peak to average power ratio (PAPR) of 7.2 dB and a channel bandwidth of 5 MHz, the PA with a drain supply voltage of 12 V exhibited an output power of 27.8 dBm, a power added efficiency (PAE) of 41.3% and power gain of 12.5 dB for the given adjacent channel leakage power ratio (ACLR) of 30 dBc. For a supply voltage of 4 V from the DC DC converter, a high PAE of 33.8% is maintained for a back off output power of 18.3 dBm.", "author_names": [ "Wonseob Lim", "Hwiseob Lee", "Hyunuk Kang", "SooHo Cho", "Youngoo Yang" ], "corpus_id": 43451304, "doc_id": "43451304", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Power amplifier based on 50 Load impedance using boost DC DC converter for APT", "venue": "2015 Asia Pacific Microwave Conference (APMC)", "year": 2015 }, { "abstract": "AlGaN/GaN HEMTs show low on state resistance and small gate capacitances, which makes them good candidates for switching applications. Up to now, their exploitations in dc/dc converters have been largely investigated in high power electronics but with switching frequencies under 1 MHz. In this brief, the potentialities of GaN HEMTs are investigated for high speed dc/dc converters. To this aim, a 10 MHz GaN 16 34 V boost converter with above 90% efficiency is presented. Such converters are well suited for high efficiency power amplifiers based on dynamic bias control for high peak to average power ratio applications.", "author_names": [ "Florent Gamand", "Ming Dong Li", "Christophe Gaquiere" ], "corpus_id": 5843358, "doc_id": "5843358", "n_citations": 35, "n_key_citations": 0, "score": 1, "title": "A 10 MHz GaN HEMT DC/DC Boost Converter for Power Amplifier Applications", "venue": "IEEE Transactions on Circuits and Systems II: Express Briefs", "year": 2012 }, { "abstract": "This paper proposes a soft start method with the features of a small on chip capacitor and start stability for dc dc converters. During the soft start process, a slowly and linearly ramped up voltage reference is generated based on the principle of the small on chip capacitor charged by an oscillator controlled pulse current to replace the normal reference. Meanwhile, the switching frequency is also reduced so that the inductor current has more time to decay and massive inrush current can be avoided. However, in this way, the system may be unstable in that the bandwidth could not keep less than 1/7 of the reduced switching frequency. In this paper, an error amplifier (EA) with gain degeneration is proposed to solve this problem. When the switching frequency is reduced, the gain of the EA is also reduced and the bandwidth becomes narrower accordingly. A dc dc converter using the proposed soft start method has been implemented with a 0.5 mm CMOS process. Experimental results show that a soft start period of 600 ms is achieved with an on chip capacitor of 15 pF. Furthermore, both the output voltage and inductor current rise smoothly without oscillation and overshoot during the startup process.", "author_names": [ "Hongyi Wang", "Yanzhao Ma", "Jun Cheng" ], "corpus_id": 28557524, "doc_id": "28557524", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Soft Start Method With Small Capacitor Charged by Pulse Current and Gain Degeneration Error Amplifier for On Chip DC DC Power Converters", "venue": "IEEE Transactions on Very Large Scale Integration (VLSI) Systems", "year": 2013 }, { "abstract": "Ilham Setiya Wardani, Saiful Manan in this paper explain that Utilization of power electronics components in the process of conversion of electrical energy has been growing from year to year. for controlling power from one form to another is very important and the characteristics of the equipment of power electronics has allowed it. DC DC converters can also be called a wave DC inverter capable of producing symmetrical widely used and applied in industry and everyday life.In the inverter power supply are made using half bridge converter topology. Half bridge converter topology has several advantages that are easy to create and output a lot easier in the controlling. The process of switching at the half bridge converter using mosfet IRFZ44N and executed using ICTL494.In the design of the tool, using the supply is 12 Volt DC that directly goes to IC TL494 and frequency output that is generated directly toward the driver mosfet with the type BC327 used to mesaklarkan mosfet by means of on off alternately to supply the power transformer intiferit to raise the voltage to 26 volt AC that will be rectified by using fast diode recofery MUR1560 to rectify the AC into DC voltage with the output voltage of 26 volts DC. Keywords: power supply, inverter, TL494 References Barkhordarian, V. Power MOSFET Basics. International Rectifier California. E book www.aosmd.com Didownload pada april 2016. Pukul 21.15 WIB. Hermawan, H. Rancang Bangun Sistem Kendali High Frequency Induction Heating Skripsi S1 Teknik Elektro. Jakarta: Universitas Indonesia. Malvino 1995. Prinsip prinsip Elektronika Jakarta Erlangga. Maruitula, Edison. 2011. Rancang Bangun Flyaback Regulator Untuk Mencatu Sistem Pensaklaran IGBT pada Invereter Skripsi S1 Teknik Elektro .Depok Unversitas Indonesia. Muis, Saludin. 2013. Perancangan Teori Dan Praktis Power Supply Jenis Switch Mode Yogyakarta Graha Ilmu. Rasyid, Muhammad H. 1999. Elektronika Daya Jakarta PT Prenhallindo.", "author_names": [ "Ilham Setiya Wardani", "Saiful Manan" ], "corpus_id": 191517675, "doc_id": "191517675", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "POWER SUPPLY INVERTER DC DC SEBAGAI SUPPLY AUDIO AMPLIFIER", "venue": "", "year": 2016 }, { "abstract": "This letter presents a resonant tunneling diode (RTD) based microwave amplifier operating at deep sub milliwatt level dc power. The fabricated amplifier, which is based on a reflection type amplifying topology and uses an InP monolithic microwave integrated circuit technology, shows extremely low dc power consumption of 125 mW with a gain of more than 10 dB at 5.7 GHz. The amplifier performance is mainly enabled by the favorable characteristics of the 0.9 mm InP based RTDs biased at VBIAS 0.36 V. The RTDs exhibit a high peak to valley current ratio (PVCR) of 11.2 with a low peak current (IP) of 430 mA and thereby a relatively low negative resistance magnitude of 480 O. The dc power consumption is about 6.4 times lower than that in transistor based low power amplifiers reported to date for the 5 GHz frequency band.", "author_names": [ "Jongwon Lee", "Jooseok Lee", "Kyounghoon Yang" ], "corpus_id": 9642952, "doc_id": "9642952", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Reflection Type RTD Low Power Amplifier With Deep Sub mW DC Power Consumption", "venue": "IEEE Microwave and Wireless Components Letters", "year": 2014 }, { "abstract": "Forward converter is one of the most studied topologies due to its lower ripple, lower parts count and hence high reliability. Owing to the need of miniaturization of Inertial Navigation System, a mini power module had to be developed for which forward converter topology was selected. A configuration of grouping the outputs into HMCS was attempted. The converter for DTG servo power amplifier had to supply the current demanded by the sensor electronics which is dynamic. Interleaved forward converter provides a better solution to satisfy the increased power and dynamic load conditions. As an added advantage, though one portion gets faulty, the other portion can provide half the maximum load, giving continuous power. The paper discusses the benefits of interleaving in the converter supplying the servo power amplifier experiencing dynamic load conditions and simulations for both single and interleaved converter design validation.", "author_names": [ "Sanjna Salim" ], "corpus_id": 8362858, "doc_id": "8362858", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Fault Tolerant DC DC Converter for DTG Servo Power Amplifier Supply", "venue": "", "year": 2014 } ]

[ { "abstract": "In this paper a hardware implementation of single phase cascaded H bridge three level multilevel inverter (MLI) using sinusoidal pulse width modulation (SPWM) is presented. There are a few interesting features of using this configuration, where less component count, less switching losses, and improved output voltage/current waveform. The output of power inverter consists of three form, that is, square wave, modified square wave and pure sine wave. The pure sine wave and modified square wave are more expensive than square wave. The focus paper is to generate a PWM signal which control the switching of MOSFET power semiconductor. The sine wave can be created by using the concept of Schmitt Trigger oscillator and low pass filter topology followed by half of the waveform will be eliminated by using the circuit of precision half wave rectifier. Waveform was inverted with 180o by circuit of inverting op amp amplifier in order to compare saw tooth waveform. Two of PWM signal were produced by circuit of PWM and used digital inverter to invert the two PWM signal before this PWM signal will be passed to 2 MOSFET driver and a 3 level output waveform with 45 Hz was produced. As a conclusion, a 3 level output waveform is produced with output voltage and current recorded at 22.5 Vrms and 4.5 Arms. The value of measured resistance is 0.015 that cause voltage drop around 0.043 V. Based on the result obtained, the power for designed inverter is around 100W and efficiency recorded at 75%", "author_names": [ "A Shamsul Rahimi A Subki", "Mohd Zaidi Mohd Tumari", "Wan Norhisyam Abd Rashid", "Aiman Zakwan Jidin", "Ahmad Nizammuddin Muhammad Mustafa" ], "corpus_id": 202792671, "doc_id": "202792671", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Hardware implementation of single phase three level cascaded h bridge multilevel inverter using sinusoidal pulse width modulation", "venue": "International Journal of Power Electronics and Drive Systems (IJPEDS)", "year": 2019 }, { "abstract": "Power converters are essential for allowing increasingly more solar energy to be connected to power systems. In this paper, a model predictive control of a three phase 7 level CHB multilevel inverter for solar energy injection is developed, using the incremental conductance algorithm for establishing an MPPT strategy which maximises PV energy from the system. In order to prove the proposed control scheme, simulations in MATLAB/Simulink are carried out. The predictive current control strategy, the dc voltage control, and the MPPT controller proved proper steady state operation and proper response in front of external disturbances. Thus, solar energy injection to the grid can be maximised using the proposed 7 level CHB multilevel inverter.", "author_names": [ "Carlos Munoz", "Ariel Villalon", "Javier A Munoz", "Marco E Rivera", "Maryam Sarbanzadeh", "Mohammad Ali Hosseinzadeh" ], "corpus_id": 195832952, "doc_id": "195832952", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Predictive Control of a Three Phase Cascaded H Bridge Multilevel Inverter for Solar Energy Injection", "venue": "2019 IEEE International Conference on Industrial Technology (ICIT)", "year": 2019 }, { "abstract": "CHB multilevel converters play a role for optimising the use of solar electricity as they allow a more efficient energy conversion. In this work, a classic control of a CHB multilevel inverter for PV energy injection is developed, considering grid disturbance compensation and an MPPT strategy for maximising PV energy. In order to prove the proposed control scheme, simulations in MATLAB/Simulink are carried out. The current control strategy, the dc voltage control, and the MPPT controller proved proper steady state operation and proper response in front of external disturbances. Additionally, the inclusion of a dynamic decoupler for the inverters output current control proved to be useful tool for controlling multilevel converters. Thus, solar energy injection to the grid can be maximised using the proposed 7 level CHB multilevel inverter.", "author_names": [ "Ariel Villalon", "Carlos Munoz", "Javier A Munoz", "Marco E Rivera", "Maryam Sarbanzadeh", "Mohammad Ali Hosseinzadeh" ], "corpus_id": 195831503, "doc_id": "195831503", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Control of a Three Phase Cascaded H Bridge Multilevel Inverter for Solar Energy Injection", "venue": "2019 IEEE International Conference on Industrial Technology (ICIT)", "year": 2019 }, { "abstract": "This paper presents fell H connect staggered inverter topology for fixed DC source and sun oriented PV application. The topology referenced in this paper represents justifies over the current customary inverters topologies. The proposed topology step up the low PV voltage, and yet checks the most extreme power through SPV cluster with the help of MPPT controller. The topology offers low present and voltage THD; likewise DC component is in reasonable breaking points. The consequences of the proposed H Bridge staggered inverter topology have been checked utilizing MATLAB Simulink model.", "author_names": [ "Kushal Anand", "Saad Nazif Ahamad Faruqui", "Asif Ali" ], "corpus_id": 209496313, "doc_id": "209496313", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Three Phase Transformerless Cascaded H Bridge Solar PV Multilevel Inverter", "venue": "2019 International Conference on Computing, Power and Communication Technologies (GUCON)", "year": 2019 }, { "abstract": "This paper proposes an advanced approach to control a cascaded H bridge multilevel photovoltaic (PV) inverter with failed cells for large scale grid connected applications. A major challenge of these PV systems come from the uneven power distribution among the PV cells on the same phase due to environmental conditions, which then leads to a power imbalance between the three phases. The power imbalance issue can also come from the presence of at least one H bridge cell fully damaged and bypassed. To produce a balanced three phase voltage and current regardless of the fact that the phase to neutral voltages are imbalanced, a neutral shift method is proposed in this paper. It is based on the modification of the PWM reference phase voltage angles combined to injection of a dynamic homopolar component. A multi carrier phase disposition PWM strategy with a switching optimization function has been also suggested.", "author_names": [ "P M Lingom", "Joseph Song-Manguelle", "Jean-Maurice Nyobe-Yome", "Daniel Legrand Mon-Nzongo", "Tao Jin", "Mamadou Lamine Doumbia" ], "corpus_id": 201623232, "doc_id": "201623232", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Control of a Cascaded H bridge Multilevel Inverter with Failed Cells for Grid Connected Application", "venue": "2019 IEEE 10th International Symposium on Power Electronics for Distributed Generation Systems (PEDG)", "year": 2019 }, { "abstract": "Inverter have a many variety of application ranging from simple converting of battery power to ac to high power HVDC transmission of electricity for a long distance. To avoid damage variable frequency drives used on large scale worldwide, make inverter very important device. This paper proposes a simple simulation model of three phase conventional inverter used for speed control of induction motor (two level) and cascade H bridge multilevel inverter(five level) used for speed control of induction motor (closed loop) using sinusoidal PWM. Hardware implementation of above mention topology is done and compare simulation results and hardware results.", "author_names": [ "Vivek D Kore", "Kunal Makarand Pisolkar", "Vidyulata Joshi", "Anish Bhurke", "Ketan M Isane" ], "corpus_id": 211206826, "doc_id": "211206826", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "5 level cascade H bridge multilevel inverter fed induction motor drive using sinusoidal PWM", "venue": "2019 2nd International Conference on Intelligent Computing, Instrumentation and Control Technologies (ICICICT)", "year": 2019 }, { "abstract": "A cascaded H bridge multilevel inverter is presented in this paper. The inverter uses only one H bridge that is excited from an isolated DC source and will be connected in cascade with a number of H bridges whose dc links are formed by floating capacitors. Floating capacitors work on the principle of level doubling and have the capability to converge to the desired steady state voltages without demanding any closed loop control techniques. In steady state, all the DC link voltages maintain a binary asymmetric ratio. The inverter generates a seventeen level phase voltage and a thirty three level line voltage at unity modulation index. Regardless of the modulation index and power factor, self balancing of capacitor voltage is achieved. Simulation of the proposed converter is carried out in MATLAB/ SIMULINK.", "author_names": [ "V Rajesh", "Sumit Kumar Chattopadhyay", "Chandan Chakraborty" ], "corpus_id": 209323217, "doc_id": "209323217", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Cascaded H Bridge Multilevel Inverter with Single DC Source for Medium Voltage Drive Applications", "venue": "IECON 2019 45th Annual Conference of the IEEE Industrial Electronics Society", "year": 2019 }, { "abstract": "This paper addresses experimental implementation of a single phase multilevel inverter consisting of three H bridge inverter cells to generate 5, 7, 9, 11 and 13 level output voltages. The proposed system consists of a microcontroller, three separate input dc sources, isolating circuits and three cascaded H bridge MOSFET based voltage source inverters. ATmega 2560 microcontroller based Arduino board has been used to generate proper gate signals for twelve MOSFETs of the three H bridge inverter cells. Twelve pins of the microcontroller has been used to generate twelve gate drive signals and the microcontroller has been programmed using simple algorithm compared to the previous techniques. Different level output voltages have been obtained from experimental works using the same cascaded H bridge inverter which require less power switching devices. The experimental results show that total harmonic distortion is reduced with increasing number of levels at the output voltage of the multilevel inverter.", "author_names": [ "Ashique Anan Abir", "Tapan Kumar Chakraborty", "Khandaker Sultan Mahmood" ], "corpus_id": 201622846, "doc_id": "201622846", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": ">An Experimental Study of Cascaded H Bridge Multilevel Inverter for Obtaining Multiple Voltage Waveforms Containing Different Number of Levels", "venue": "2019 IEEE 10th International Symposium on Power Electronics for Distributed Generation Systems (PEDG)", "year": 2019 }, { "abstract": "A Multilevel Inverter that uses less hardware, which is energy efficient and has reduced switching and conduction losses is proposed. This topology is developed from a symmetrical structure enhanced multilevel inverter (MLI) It consists of a seventeen level symmetrical structure enhanced H Bridge, a DC source in series with the load through a switch and another switch to bypass the DC input source. By way of the addition of a DC input source, the number of levels of the proposed inverter has been increased to thirty three; hence, the total harmonic distortion (THD) is reduced. Only four switches are in its active conducting state in each mode of operation due to which the power losses are reduced compared to a CHB and Developed H Bridge MLI. The proposed single phase multilevel inverter is simulated using MATLAB/ Simulink, and the results have been confirmed experimentally with a prototype.", "author_names": [ "Tamizhselvan Annamalai", "K Udhayakumar", "S Anitha", "D Pachaikani", "P Sasikumar", "M R Mythily" ], "corpus_id": 209457511, "doc_id": "209457511", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Energy Efficient Reference Tracking Modified Enhanced H Bridge Multilevel Inverter", "venue": "2019 IEEE 1st International Conference on Energy, Systems and Information Processing (ICESIP)", "year": 2019 }, { "abstract": "ABSTRACT This paper presents a new voltage regulation structure for multilevel inverters using discrete variation of DC sources. In the proposed method, discrete variation is achieved based on multi tap transformers for applications where the DC sources are isolated and supplied by three phase transformers, e.g. medium voltage (MV) motor drive applications. Moreover, by utilising the new solution, the number of required DC regulators is reduced significantly, for applications where the optimum modulation index with variable DC sources is used which suffer from large number of required converters. In addition, this paper proposes a new algorithm for optimising the switching angles, turn ratios of the multi tap transformers and DC sources to maintain the voltage distortions at the standards levels for a wide range of output voltage regulation. To verify the feasibility of the new solution, a laboratory prototype is implemented based on a 2 cell cascaded H bridge (CHB) multilevel inverter with unequal DC sources (with 9 level operation) while the proposed structure can be applied for other CHB multilevel inverters and switching strategies.", "author_names": [ "Ahmad Behzadi Nezhad", "Alireza Namadmalan", "Ali Rahdarian" ], "corpus_id": 131882900, "doc_id": "131882900", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Cascaded H bridge multilevel inverters with discrete variation of DC sources", "venue": "International Journal of Electronics", "year": 2019 } ]

[ { "abstract": "Photocatalytic conversion of CO2 into carbonaceous feedstock chemicals is a promising strategy to mitigate greenhouse gas emissions and simultaneously store solar energy in chemical form. Photocatalysts for this transformation are typically based on precious metals and operate in nonaqueous solvents to suppress competing H2 generation. In this work, we demonstrate selective visible light driven CO2 reduction in water using a synthetic photocatalyst system that is entirely free of precious metals. We present a series of self assembled nickel terpyridine complexes as electrocatalysts for the reduction of CO2 to CO in organic media. Immobilization on CdS quantum dots allows these catalysts to be active in purely aqueous solution and photocatalytically reduce CO2 with >90% selectivity under UV filtered simulated solar light irradiation (AM 1.5G, 100 mW cm 2, l 400 nm, pH 6.7, 25 degC) Correlation between catalyst immobilization efficiency and product selectivity shows that anchoring the molecular catalyst on the semiconductor surface is key in controlling the selectivity for CO2 reduction over H2 evolution in aqueous solution.", "author_names": [ "Moritz F Kuehnel", "Katherine L Orchard", "Kristian E Dalle", "Erwin Reisner" ], "corpus_id": 30858244, "doc_id": "30858244", "n_citations": 230, "n_key_citations": 1, "score": 0, "title": "Selective Photocatalytic CO2 Reduction in Water through Anchoring of a Molecular Ni Catalyst on CdS Nanocrystals.", "venue": "Journal of the American Chemical Society", "year": 2017 }, { "abstract": "AbstractDistinguishing the toxic effects of nanoparticles (NPs) themselves from the well studied toxic effects of their ions is a critical but challenging measurement for nanotoxicity studies and regulation. This measurement is especially difficult for silver NPs (AgNPs) because in many relevant biological and environmental solutions, dissolved silver forms AgCl NPs or microparticles. Simulations predict that solid AgCl particles form at silver concentrations greater than 0.18 and 0.58 mg/mL in cell culture media and moderately hard reconstituted water (MHRW) respectively. The AgCl NPs are usually not easily separable from AgNPs. Therefore, common existing total silver techniques applied to measure AgNP dissolution, such as inductively coupled plasma mass spectrometry (ICP MS) or atomic absorption, cannot accurately measure the amount of silver remaining in AgNP form, as they cannot distinguish Ag oxidation states. In this work, we introduce a simple localized surface plasmon resonance (LSPR) UV visible absorbance measurement as a technique to measure the amount of silver remaining in AgNP form for AgNPs with constant agglomeration states. Unlike other existing methods, this absorbance method can be used to measure the amount of silver remaining in AgNP form even in biological and environmental solutions containing chloride because AgCl NPs do not have an associated LSPR absorbance. In addition, no separation step is required to measure the dissolution of the AgNPs. After using ICP MS to show that the area under the absorbance curve is an accurate measure of silver in AgNP state for unagglomerating AgNPs in non chloride containing media, the absorbance is used to measure dissolution rates of AgNPs with different polymer coatings in biological and environmental solutions. We find that the dissolution rate decreases at high AgNP concentrations, 5 kDa polyethylene glycol thiol coatings increase the dissolution rate, and the rate is much higher in cell culture media than in MHRW. Figure", "author_names": [ "Justin M Zook", "Stephen E Long", "Danielle M Cleveland", "Carly Lay A Geronimo", "Robert I MacCuspie" ], "corpus_id": 37674937, "doc_id": "37674937", "n_citations": 190, "n_key_citations": 3, "score": 0, "title": "Measuring silver nanoparticle dissolution in complex biological and environmental matrices using UV visible absorbance", "venue": "Analytical and bioanalytical chemistry", "year": 2011 }, { "abstract": "Abstract M/TiO2 photocatalyst activity for H2 production depends on both the metal co catalyst (M) and the reaction medium. To quantify such effects, we compared the performance of M/TiO2 photocatalysts (M Pd, Pt, Au) for H2 production in different alcohol water mixtures under UV excitation. Photocatalysts were prepared using Degussa P25 TiO2 at metal loadings of 0.5 and 1 wt. for Pd, 1 wt. for Pt and 1 wt. for Au. TEM, UV Vis, XPS and EXAFS analyses confirmed the presence of supported metal nanoparticles of size ~2, 1.3 and 5.4 nm for Pd/TiO2, Pt/TiO2 and Au/TiO2, respectively. Photoluminescence data established that the metal co catalysts effectively suppressed electron hole pair recombination in TiO2 following photo excitation. The activities of the M/TiO2 photocatalysts for H2 production were evaluated in a wide range of alcohol water mixtures (alcohol concentration 10 vol. under UV (365 nm, 5 mW cm 2) H2 production rates in the alcohol water mixtures were dependent on (i) the metal co catalyst; (ii) the co catalyst loading; and (iii) the alcohol type. Co catalyst activity followed the order Pd Pt Au. The highest H2 production rates were achieved for the 1 wt. Pd/TiO2 photocatalyst in glycerol water mixtures (47.5 mmol g 1 h 1) and 1,2 ethanediol water mixtures (44.5 mmol g 1 h 1) H2 production rates decreased in the order glycerol 1,2 ethanediol 1,2 propanediol methanol ethanol 2 propanol tert butanol water. For each M/TiO2 photocatalyst, correlations were established between the rate of H2 production and specific alcohol properties, especially alcohol polarity and the exponential of the alcohol oxidation potential.", "author_names": [ "Zakiya H N Al-Azri", "Wan-Ting Chen", "Andrew Chan", "Vedran Jovic", "Toshiaki Ina", "Hicham Idriss", "Geoffrey I N Waterhouse" ], "corpus_id": 92874838, "doc_id": "92874838", "n_citations": 188, "n_key_citations": 1, "score": 0, "title": "The roles of metal co catalysts and reaction media in photocatalytic hydrogen production: Performance evaluation of M/TiO2 photocatalysts (M Pd, Pt, Au) in different alcohol water mixtures", "venue": "", "year": 2015 }, { "abstract": "Over the last decade, ultraviolet light emitting diodes (UV LEDs) have attracted considerable attention as alternative mercury free UV sources for water treatment purposes. This review is a comprehensive analysis of data reported in recent years (mostly, post 2014) on the application of UV LED induced advanced oxidation processes (AOPs) to degrade organic pollutants, primarily dyes, phenols, pharmaceuticals, insecticides, estrogens and cyanotoxins, in aqueous media. Heterogeneous TiO2 based photocatalysis in lab grade water using UVA LEDs is the most frequently applied method for treating organic contaminants. The effects of controlled periodic illumination, different TiO2 based nanostructures and reactor types on degradation kinetics and mineralization are discussed. UVB and UVC LEDs have been used for photo Fenton, photo Fenton like and UV/H2O2 treatment of pollutants, primarily, in model aqueous solutions. Notably, UV LED activated persulfate/peroxymonosulfate processes were capable of providing degradation in DOC containing waters. Wall plug efficiency, energy efficiency of UV LEDs and the energy requirements in terms of Electrical Energy per Order (EEO) are discussed and compared. Despite the overall high degradation efficiency of the UV LED based AOPs, practical implementation is still limited and at lab scale. More research on real water matrices at more environmentally relevant concentrations, as well as an estimation of energy requirements providing fluence based kinetic data are required.", "author_names": [ "Galina Matafonova", "Valeriy B Batoev" ], "corpus_id": 4699774, "doc_id": "4699774", "n_citations": 178, "n_key_citations": 0, "score": 1, "title": "Recent advances in application of UV light emitting diodes for degrading organic pollutants in water through advanced oxidation processes: A review.", "venue": "Water research", "year": 2018 }, { "abstract": "Abstract This work prepared palladium doped titanium dioxide (Pd doped TiO2) catalysts by a facile sol gel method to enhance degradation of single and binary methylene blue and methyl orange by ultraviolet photocatalysis. The physicochemical properties of Pd doped TiO2 particles were analyzed by a X ray powder diffractometer, X ray photoelectron spectroscope, scanning electron microscope, transmission electron microscope, UV visible diffuse reflectance spectroscope, sorptiometer, and transient photocurrent spectroscope. More efficient degradation was achieved in acidic and basic/neutral media for methyl orange and methylene blue, respectively. Also, methylene blue was always degraded faster than methyl orange. The highest degradation efficiency of both dyes in single and binary systems was obtained using 0.5 wt. and 0.75 wt. Pd TiO2, respectively. The degradation pathways of single methylene blue and methyl orange with Pd doped TiO2 and commercial P25 TiO2 were proposed and compared by identifying reaction intermediates produced during photocatalysis. Recycling tests have confirmed excellent stability of Pd TiO2 materials. Also, the prepared materials were easier to separate from the treated liquid using a simple sedimentation or filtration method than P25 TiO2. In particular, the use of sol gel method could readily synthesize a large number of catalysts, which was beneficial for scale up consideration. All these factors highlighted their potential and prospect in practical applications for water reuse.", "author_names": [ "Chi Hieu Nguyen", "Chun-Chieh Fu", "Ruey-Shin Juang" ], "corpus_id": 158047866, "doc_id": "158047866", "n_citations": 172, "n_key_citations": 0, "score": 0, "title": "Degradation of methylene blue and methyl orange by palladium doped TiO2 photocatalysis for water reuse: Efficiency and degradation pathways", "venue": "", "year": 2018 }, { "abstract": "Perfluorooctane sulfonate (PFOS) is the environmentally concerned compound because of its persistence and bioaccumulative properties. Since photodegradation of PFOS is not yet experimentally confirmed, photodegradation study of PFOS in water and alkaline 2 propanol solution was conducted. Aqueous and alkaline 2 propanol solution of PFOS (40 microM) was irradiated with a low pressure mercury lamp (254 nm, 32 W) by internal irradiation for 10 d, and then PFOS, fluoride and sulfate ions, and the other degradation products were analyzed. Photodegradation of PFOS was confirmed in both media. PFOS was degraded by 8% after 1 day and by 68% after 10 days irradiation compared to the initial concentration in water. In alkaline 2 propanol, 76 and 92% of PFOS was degraded after 1 and 10 days irradiation, respectively. Photodegradation of PFOS in alkaline 2 propanol was much faster and effective than in water, as the photodegradation rate constants were 0.93 days( 1) in alkaline 2 propanol and 0.13 days( 1) in water, respectively. Formation of fluoride and sulfate was also confirmed by ion chromatography and X ray diffraction analysis. From observation of the degradation products, two major degradation pathways of PFOS were considered: via C8HF17 and C8F17OH, respectively, resulting in short chain fluorinated compounds such as C7HF15 and C7F15OH by stepwise removal of CF2. Formation of short chain fluorocarbons such as CF4, C2F6, and C3F8 were also confirmed. This is the first study to confirm photodegradation of PFOS in water and alkaline 2 propanol.", "author_names": [ "Takashi Yamamoto", "Yukio Noma", "Shin-ichi Sakai", "Yasuyuki Shibata" ], "corpus_id": 21115783, "doc_id": "21115783", "n_citations": 125, "n_key_citations": 8, "score": 0, "title": "Photodegradation of perfluorooctane sulfonate by UV irradiation in water and alkaline 2 propanol.", "venue": "Environmental science technology", "year": 2007 }, { "abstract": "The pKa values of nine polyphenolic acid substances in water and acetonitrile water mixtures using potentiometric, spectrophotometric, and liquid chromatographic (LC) measurements, have been determined. Also, a new method based on the absorbance spectra at the maximum of chromatographic peaks previously obtained has been applied. This method can be applied to data obtained from LC UV (diode array detection (DAD) instruments and retains all the advantages of LC and spectrophotometric methods, such as the possibility of working with impure samples. Finally, the advantages of the different methods to the determination of pKa values of nine polyphenolic acids have been described in order to verify the applicability of the proposed methods in aqueous and acetonitrile water media. (c) 2003 Elsevier Science B.V. All rights reserved.", "author_names": [ "Jose Luis Beltran", "Nurullah Sanli", "Gemma Fonrodona", "Dolores Barron", "Guleren Ozkan", "Jose Barbosa" ], "corpus_id": 96203871, "doc_id": "96203871", "n_citations": 98, "n_key_citations": 6, "score": 0, "title": "Spectrophotometric, potentiometric and chromatographic pKa values of polyphenolic acids in water and acetonitrile water media", "venue": "", "year": 2003 }, { "abstract": "Urban wastewater treatment plants (UWTPs) are among the main hotspots of antibiotic resistance (AR) spread into the environment and the role of conventional and new disinfection processes as possible barrier to minimise the risk for AR transfer is presently under investigation. Accordingly, the aim of this work was to evaluate the effect of an advanced oxidation process (AOP) (specifically UV/H2O2) on AR transfer potential. UV/H2O2 disinfection experiments were carried out on real wastewater samples to evaluate the: i) inactivation of total coliforms, Escherichia coli and antibiotic resistant E. coli as well as ii) possible removal of target antibiotic resistance genes (ARGs) (namely, blaTEM, qnrS and tetW) In particular, DNA was extracted from both antibiotic resistant E. coli bacterial cells (intracellular DNA) grown on selective culture media, and the whole water suspension (total DNA) collected at different treatment times. Polymerase chain reaction (PCR) assay was performed to detect the absence/presence of the selected ARGs. Real Time quantitative Polymerase Chain Reaction (qPCR) was used to quantify the investigated ARGs in terms of copiesmL( 1) In spite of the bacterial inactivation and a decrease of ARGs in intracellular DNA after 60min treatment, UV/H2O2 process was not effective in ARGs removal from water suspension (total DNA) Particularly, an increase up to 3.7x10(3)copiesmL( 1) (p>0.05) of blaTEM gene was observed in total DNA after 240min treatment, while no difference (p>0.05) was found for qnrS gene between the initial (5.1x10(4)copiesmL( 1) and the final sample (4.3x10(4)copiesmL( 1) On the base of the achieved results, the investigated disinfection process may not be effective in minimising AR spread potential into the environment. The death of bacterial cells, which results in DNA release in the treated water, may pose a risk for AR transfer to other bacteria present in the receiving water body.", "author_names": [ "Giovanna Ferro", "Francesco Guarino", "Stefano Castiglione", "Luigi Rizzo" ], "corpus_id": 24788471, "doc_id": "24788471", "n_citations": 93, "n_key_citations": 0, "score": 0, "title": "Antibiotic resistance spread potential in urban wastewater effluents disinfected by UV/H2O2 process.", "venue": "The Science of the total environment", "year": 2016 }, { "abstract": "Unlike that for cadmium based nanocrystals, little research has been found on the synthesis of the UV blue emitting ZnSe based QDs with photoluminescence (PL) quantum yield (QY) superior to 50% In this article, high quality water dispersible ZnSe/ZnS core/shell nanocrystals have been prepared in aqueous media. The epitaxial overgrowth of the ZnS shell was carried out at 90 degC in a reaction flask consisting of the shell precursor compounds (zinc acetae as zinc resource and thiourea as sulfur resource) together with the as prepared ZnSe core nanocrystals and the capping reagent glutathione. The optical features and structure of the obtained ZnSe/ZnS core/shell nanocrystals have been characterized by UV vis, PL spectroscopy, transmission electron microscopy (TEM) X ray diffraction (XRD) and energy dispersive X ray analysis (EDX) The influences of various experimental variables, including amounts of ligand and thiourea as well as pH value, on the growth rate and luminescent properties of the obtained cor.", "author_names": [ "Zheng Fang", "Yan Li", "Hua Zhang", "Xinhua Zhong", "Linyong Zhu" ], "corpus_id": 94058890, "doc_id": "94058890", "n_citations": 88, "n_key_citations": 0, "score": 0, "title": "Facile Synthesis of Highly Luminescent UV Blue Emitting ZnSe/ZnS Core/Shell Nanocrystals in Aqueous Media", "venue": "", "year": 2009 }, { "abstract": "Abstract In this work, we evaluate the effect of nanoparticles and nanofluids as viscosity reducers for heavy crude oil (HO) The effect of alumina, silica and acidic silica nanoparticles was evaluated through n C7 asphaltene adsorption and aggregation tests using UV vis spectrophotometry and dynamic light scattering. The nanoparticles of acidic silica were used to prepare a water based nanofluid at different concentrations in distilled water, and also with the addition of 2.0 wt% of a non ionic surfactant. The shear rheological response was obtained as function of nanoparticle concentration, temperature (from 298 to 323 K) and shear rate (ranging from 0 to 100 s 1) Experimental results indicate that increasing the concentration of nanoparticles in the mixture, up to 10,000 ppm, leads to a viscosity reduction of approximately 90% in comparison with the nanoparticle free crude oil. At higher concentration of nanoparticles, the effectiveness of the heavy oil viscosity reduction diminishes. Rheological tests showed a non Newtonian behavior for the mixtures tested at 298 K. However, as the temperature reaches 323 K the specimens behave in a Newtonian fashion. Coreflooding tests were conducted under typical reservoir conditions of pore and overburden pressures, i.e. 2600 and 3600 psi, respectively, and at 360 K. Results indicate that the addition of nanoparticles increases the heavy oil mobility and leads to an improvement in oil recovery of roughly 16%", "author_names": [ "Esteban A Taborda", "Camilo A Franco", "Sergio H Lopera", "Vladimir Alvarado", "Farid B Cortes" ], "corpus_id": 100166229, "doc_id": "100166229", "n_citations": 88, "n_key_citations": 1, "score": 0, "title": "Effect of nanoparticles/nanofluids on the rheology of heavy crude oil and its mobility on porous media at reservoir conditions", "venue": "", "year": 2016 } ]

[ { "abstract": "In contrast to interband excitons in undoped quantum wells, doped quantum wells do not display sharp resonances due to excitonic bound states. The effective Coulomb interaction between electrons and holes in these systems typically leads to only a depolarization shift of the single electron intersubband transitions 1 Non perturbative light matter interaction in solid state devices has been investigated as a pathway to tuning optoelectronic properties of materials 2 3 A recent theoretical work 4 predicted that when the doped quantum wells are embedded in a photonic cavity, emission reabsorption processes of cavity photons can generate an effective attractive interaction that binds electrons and holes together, leading to the creation of an intraband bound exciton. Here, we spectroscopically observe such a bound state as a discrete resonance that appears below the ionization threshold only when the coupling between light and matter is increased above a critical value. Our result demonstrates that two charged particles can be bound by the exchange of transverse photons. Light matter coupling can thus be used as a tool in quantum material engineering, tuning electronic properties of semiconductor heterostructures beyond those permitted by mere crystal structures, with direct applications to mid infrared optoelectronics. Electrons and holes in doped quantum wells cannot form bound states from usual Coulomb interaction. However, when the system is embedded in a cavity, the exchange of photons provides an effective attraction, leading to the creation of bound excitons.", "author_names": [ "Erika Cortese", "N L Tran", "J-M Manceau", "Adel Bousseksou", "Iacopo Carusotto", "Giorgio Biasiol", "Raffaele Colombelli", "Simone De Liberato" ], "corpus_id": 209324307, "doc_id": "209324307", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "Excitons bound by photon exchange", "venue": "", "year": 2019 }, { "abstract": "In semimagnetic semiconductors, magnetic polaron bound to donors and acceptors have been well studied [1] and are now well understood theoretic cally [2 4] Despite the fact that magnetic polaron shift in the luminescence of bound excitons were studied since 1980 [5 6] many aspects are still to be explained. In this paper, we use the best available wavefunc tions of exciton complexes [7 8] We compute the contribution of exchange between the magnetic ions and the bound particles as a perturbation. The process involving the impurity Ideg, the exciton X and the photon hvis: X Ideg IdegX hv+ IdegAt the time of photon emission, we can admit safely that a strong dipolar allowed process occurs with conservation of the magnetization. But since the lifetime of the excited state is known to be about 1 nsec, we have to wonder if the magnetic moments have time to adjust to the electronic exci ted state. Calculations are done in the two limits: a) Slow orientation of the moments. The magnetization map M(r) at the time of luminescence is fixed by thermalization in the ground state Ideg. b) Fast orientation of th moments. M(r) is fixed by thermalization in the IdegX state.", "author_names": [ "R Planel", "J Cernogora", "Jan A Gaj", "Christophe L Guillaume" ], "corpus_id": 100419762, "doc_id": "100419762", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Magnetic Polaron Effects on Bound Excitons", "venue": "", "year": 1985 }, { "abstract": "Within the framework of ab initio Time Dependent Density Functional Theory (TD DFT) we propose a static approximation to the exchange correlation kernel based on the jellium with gap model. This kernel accounts for electron hole interactions and it is able to address both strongly bound excitons and weak excitonic effects. TD DFT absorption spectra of several bulk materials (both semiconductor and insulators) are reproduced in very good agreement with the experiments and with a low computational cost. The theoretical description of the optical properties of materials by first principles calculations is one of the classical issues in solid state physics. After photon absorption, the excitonic effects, driven by the electron and hole (e h) interactions, are principal actors, rendering the ab initio computational description demanding. The most successful approach is, so far, based on ManyBody Perturbation theory: the GW self energy accounts for electron electron (e e) many body effects in the band structure calculations, whereas the Bethe Salpeter Equation is solved to introduce e h interactions [1] This accu", "author_names": [ "Paolo E Trevisanutto", "Aleksandrs Terentjevs", "Lucian A Constantin", "V Olevano", "Fabio Della Sala" ], "corpus_id": 119310448, "doc_id": "119310448", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Optical Spectra of Solids Obtained by Time Dependent Density Functional Theory with the Jellium with Gap Model Exchange Correlation Kernel", "venue": "", "year": 2013 }, { "abstract": "Quantum communication networks require on chip transfer and manipulation of single particles as well as their interconversion to single photons for long range information exchange. Flying excitons propelled by GHz surface acoustic waves (SAWs) are outstanding messengers to fulfill these requirements. Here, we demonstrate the acoustic manipulation of two level states consisting of individual excitons bound to shallow impurities centers embedded in a semiconductor quantum well. Time resolved photoluminescence studies show that the emission intensity and energy from these centers oscillate at the SAW frequency of 3.5 GHz. Furthermore, these centers can be remotely pumped via acoustic transport along a quantum well channel over several micron. Time correlation studies reveal that the centers emit anti bunched light, thus acting as single photon sources operating at GHz frequencies. Our results pave the way for the exciton based on demand manipulation and on chip transfer of single excitons at microwave frequencies with a natural photonic interface.", "author_names": [ "M Yuan", "Klaus Biermann", "Shin-ya Takada", "C Bauerle", "Paulo Ventura Santos" ], "corpus_id": 218581318, "doc_id": "218581318", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Remotely pumped GHz anti bunched emission from single exciton states", "venue": "", "year": 2020 }, { "abstract": "In cavity quantum electrodynamics, strong light matter coupling is normally observed between a photon mode and a discrete optically active transition. In the present work we demonstrate that strong coupling can also be achieved using ionizing, intrinsically continuum, transitions. This leads to the appearance of novel discrete polaritonic resonances, corresponding to dressed bound exciton states, kept together by the exchange of virtual cavity photons. We apply our theory to the case of intersubband transitions in doped quantum wells, where Coulomb bound excitons are absent. In considering quantum wells with a single bound electronic subband, in which all transitions involve states in the continuum, we find that the novel bound excitons predicted by our theory are observable within present day, realistic parameters. Our work shows how strong light matter coupling can be used as a novel gauge to tune both optical and electronic properties of semiconductor heterostructures beyond those permitted by mere crystal properties.", "author_names": [ "Erika Cortese", "Iacopo Carusotto", "Raffaele Colombelli", "Simone De Liberato" ], "corpus_id": 209455335, "doc_id": "209455335", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Strong coupling of ionizing transitions", "venue": "Optica", "year": 2019 }, { "abstract": "Oxygen substituting for Te in ZnTe is an isoelectronic impurity that traps excitons. The recombination radiation and absorption spectra attributed to isolated oxygen centers exhibit a no phonon line accompanied by emission of multiple phonons. The two resulting spectra are `mirror images' of each other in energy with respect to that of the no phonon line. Photoluminescence and absorption measurements on specimens with significantly higher oxygen concentration disclosed additional spectral features with four no phonon lines, all displaced to lower energies with respect to that of isolated oxygen. Photoluminescence spectra of the present no phonon lines show a temperature dependence characteristic of exchange coupling between an electron and a hole. Selective excitation with photon energies less than that of the no phonon line of isolated oxygen permitted a clear observation of the features free from the phonon sidebands of isolated oxygen. These features, including phonon replicas, appear to be due to excitons bound to oxygen pairs, with different OO separations.", "author_names": [ "Maeng-Je Seong", "Ireneusz Miotkowski", "Anant K Ramdas" ], "corpus_id": 122565878, "doc_id": "122565878", "n_citations": 40, "n_key_citations": 0, "score": 0, "title": "OXYGEN ISOELECTRONIC IMPURITIES IN ZNTE: PHOTOLUMINESCENCE AND ABSORPTION SPECTROSCOPY", "venue": "", "year": 1998 }, { "abstract": "SummaryThe existence of the excitonic molecule as bound state of Wannier excitons was predicted since 1958. In recent years new lines were observed in the luminescence spectra of crystals excited by high power lasers. These lines were attributed to the dissociation of the molecule into a free exciton and a photon. We establish the classification of the biexcitonic states taking into account the details of the band structure and the symmetry properties of the crystals. Different numerical calculations of the binding energy of the molecule are presented, some including electron hole exchange corrections. Discrepancies still exist between different authors. According to the group theoretical classification of the biexciton states, selection rules of luminescence and two photon absorption are derived. For two photon absorption, besides the usual selection rules for dipole transitions, dynamical selection rules were evidenced.RiassuntoFin dal 1958 si e predetta l'esistenza della molecola eccitonica come stato legato degli eccitoni di Wannier. Negli anni recenti si sono osservate nuove righe negli spettri di luminescenza di cristalli eccitati da laser di alta potenza. Queste linee sono state attribuite alla dissociazione della molecola in un eccitone libero e in un fotone. Si stabilisce la classificazione degli stati bieccitonici prendendo in considerazione i dettagli della struttura a bande e le proprieta di simmetria dei cristalli. Si presentano diversi calcoli numerici dell'energia di legame delle molecole, alcuni comprendenti correzioni dovute allo scambio elettrone buca. Esistono ancora discrepanze tra i diversi autori. Si derivano, seguendo la classificazione degli stati bieccitonici secondo la teoria dei gruppi, le regole di selezione della luminescenza e dell'assorbimento a due fotoni. Per l'assorbimento a due fotoni sono state messe in evidenza, accanto alle usuali regole di selezione per le transizioni dipolari, regole di selezione dinamiche.ReziumeSushchestvovanie eksitonnoi molekuly, kak sviazannogo sostoianiia eksitonov vann'e, bylo predskazano v 1958. V poslednie gody nabliudalis' novye linii v spektrakh liuminestsentsii kristallov, vozbuzhdaemykh lazerami s vysokoi intensivnost'iu. Eti linii pripisyvaiutsia dissotsiatsii molekuly na svobodnyi eksiton i foton. My ustanavlivaem klassifikatsiiu bieksitonnykh sostoianii, prinimaia vo vnimanie detali zonnoi struktury i svoistva simmetrii kristallov. Predlagaiutsia razlichnye vychisleniia energii sviazi molekuly, kotorye vkliuchaiut elektron dyrochnye obmennye popravki. Otmechaiutsia raskhozhdeniia mezhdu dannymi raznykh avtorov. V sootvetstvii s klassifikatsiei teorii grupp dlia bieksitonnykh sostoianii, vyvodiatsia pravila otbora dlia liuminestsentsii i dvukhfotonnogo pogloshcheniia. Dlia dvukhfotonnogo pogloshcheniia, krome obychnykh pravil otbora dlia dipol'nykh perekhodov, podtverzhdaiutsia dinamicheskie pravila otbora.", "author_names": [ "Antonio Quattropani", "J J Forney" ], "corpus_id": 118709263, "doc_id": "118709263", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Theory of excitonic molecules", "venue": "", "year": 1977 }, { "abstract": "The inelastic collision of two excitons or the optical decay of a biexciton can induce a transition into an exciton and a photon. From the symmetry point of view, we have studied the states of free and bound biexcitons in bulk GaN with the wurtzite structure and in GaN/AlN heterostructures. Due to the antisymmetry properties arising from the exchange of identical fermions, the ground state of the free G biexcitons involving two holes from the same valence band is totally symmetric with respect to the symmetry group of the structure. We established the optical selection rules as well as the possible channels for the processes mentioned above and showed that, whatever is the symmetry of a biexciton, there are at least two channels for its optical recombination. That suggests fast recombination processes. If one (several) phonon(s) is (are) involved in a process, it is always possible to connect by an optical transition any initial state to any final one. An electric field applied parallel to the growth axis lowers the symmetry of superlattices to that of quantum wells. All the results remain valid for any bulk semiconductor with the wurtzite structure and for any wurtzite based heterostructure with identical cations or anions. (c) 2004 WILEY VCH Verlag GmbH Co. KGaA, Weinheim)", "author_names": [ "P Tronc", "Yu E Kitaev", "Vyacheslav P Smirnov", "M A Jacobson", "Gerard Neu" ], "corpus_id": 97140831, "doc_id": "97140831", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Symmetry aspects of exciton exciton interactions and biexciton transitions in wurtzite semiconductor structures", "venue": "", "year": 2004 }, { "abstract": "We experimentally demonstrate the existence of bound excitonic resonances in doped quantum wells whose electron and hole are bind by the exchange of virtual cavity photons.", "author_names": [ "Erika Cortese", "L-N Tran", "J-M Manceau", "Giorgio Biasiol", "Iacopo Carusotto", "Raffaele Colombelli", "Simone De Liberato" ], "corpus_id": 204822389, "doc_id": "204822389", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Cavity mediated bound excitons", "venue": "2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW THz)", "year": 2019 }, { "abstract": "Abstract CdWO4:Sm single crystals were studied by optical, electron paramagnetic and thermoluminescence spectroscopy in the temperature range of 4 750 K. A hopping diffusion of self trapped excitons and energy transfer to Sm3+ centres is demonstrated. The mechanism of energy transfer includes the formation of a Sm3+ bound exciton either by direct excitation or in the result of a thermally stimulated hopping diffusion of self trapped excitons as well as a sequential trapping of charge carriers near the Sm3+ ions. The energy transfer from the perturbed excitons to Sm3+ ions is controlled by an electric dipole dipole or exchange interaction and it is terminated in the temperature range of 450 650 K due to the thermal destruction of Sm3+ perturbed excitons. In the case of near surface excitations created in the energy region of high absorption coefficients by 5 eV photons, the Sm3+ emission is additionally quenched by surface induced quenching centres.", "author_names": [ "Vitali Nagirnyi", "Dmitry A Spassky", "Valentyn Laguta", "Maksym Buryi", "Marco Kirm", "Sergey Omelkov", "Ivo Romet", "I A Tupitsyna", "Pieter Dorenbos" ], "corpus_id": 224973276, "doc_id": "224973276", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Energy transfer to luminescent impurity by thermally quenching excitons in CdWO4:Sm", "venue": "", "year": 2020 } ]

[ { "abstract": "Threshold Inverter Quantizer (TIQ) is a novel idea which can effectively replace the reference voltage generator, resistive/capacitive voltage divider network and array of differential comparators in a conventional flash Analog to Digital Converter (ADC) by an internal reference comparator array constructed of Complementary Metal Oxide Semiconductor (CMOS) inverters. The inverter threshold voltage serving as the reference voltage, this architecture claims large improvements in terms of silicon area, power consumption and operating speed. Perturbations due to sensitivity of the inverter threshold voltage to operating temperature/process variations pose impediments in such ADC designs and strongly demand a compensation scheme to such variations. This paper presents a TIQ based flash ADC, with inverter threshold voltage compensation for a flash ADC architecture which is thermally reliable up to 120 degC. The complete circuit is modeled in cadence virtuoso simulation suite with gpdk 180 nm design library.", "author_names": [ "George M Joseph", "Talaat A Hameed" ], "corpus_id": 235206334, "doc_id": "235206334", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "TIQ flash ADC with threshold compensation", "venue": "2021 5th International Conference on Intelligent Computing and Control Systems (ICICCS)", "year": 2021 }, { "abstract": "This paper was presented the design of a threshold inverter quantized (TIQ) comparator in flash analog to digital converter. The TIQ comparator has a high speed response; however this circuit involves a lot of transistors hence wasteful power consumption. The design is intended to obtain a low power TIQ comparator and reduces the area of the chip in 0.18 um CMOS technology. The method was proposed to set each of the transistor channel length for the threshold voltage difference gained of the inverter each in the TIQ comparator and adding a transistor as compensation to overcome the limitations of the length channel expansion due to the body effect influence. This method has reduced the drain current of CMOS transistors; hence the power dissipation can be reduced. The event has achieved low power dissipation of 31.14 uW and a chip size of 1065 um2 with 0 to 0.6 V input signal condition.", "author_names": [ "Al Al", "Mamun Bin Ibne Reaz", "Jubayer Jalil", "Mohd Alauddin Mohd Ali" ], "corpus_id": 3509867, "doc_id": "3509867", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "An Improved A Low Power CMOS TIQ Comparator Flash ADC", "venue": "", "year": 2014 }, { "abstract": "This brief presents the design of an energy efficient flash analogue to digital converter (ADC) with threshold inverter quantiser comparator employing advanced body biasing to compensate for the effects of parameter variability. The proposed calibration scheme is verified against process, voltage, and temperature corners as well as random parameter variability (mismatch) Two proof of concept ADCs of 4 and 6 bit precision are designed and verified in simulations in 28 nm fully depleted silicon on insulator technology. The 6 bit converter achieves sampling rate of 3 GS/s, energy efficiency per conversion step below 20 fJ, and precision of 5.2 effective number of bits. The proposed ADC architecture is dedicated to high speed and low precision applications, such as communication transceivers and data acquisition systems where area and energy efficiency are paramount.", "author_names": [ "Przemyslaw Mroszczyk", "John Goodacre", "Vasilis F Pavlidis" ], "corpus_id": 116022132, "doc_id": "116022132", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Energy Efficient Flash ADC With PVT Variability Compensation Through Advanced Body Biasing", "venue": "IEEE Transactions on Circuits and Systems II: Express Briefs", "year": 2019 }, { "abstract": "A Threshold Inverter Quantization (TIQ) architecture for Flash Analog to Digital Converters (ADCs) uses inverters as a voltage comparator. TIQ approach has many advantages over a differential voltage comparator, but it is hard to create and select comparators for it. Precise selection of gate switching voltage is crucial for Flash Analog to Digital Converters (ADCs) Therefore, Differential Non Linearity (DNL) and Integral Non Linearity (INL) error measurements are used to understand how precisely voltage comparators are selected. Different selection algorithms are used to make selection as precise as possible. In this work, we present two new algorithms based on a dynamic programming approach along with DNL and INL simulation results. Comparison with state of the art methods, 4 times, and 5 times DNL improvements are achieved through the new approach for 6 bit and 8 bit respectively.", "author_names": [ "Ali Ozdemir", "Mshabab Alrizah", "Kyusun Choi" ], "corpus_id": 202700952, "doc_id": "202700952", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Optimization of Comparator Selection Algorithm for TIQ Flash ADC Using Dynamic Programming Approach", "venue": "2019 IEEE Computer Society Annual Symposium on VLSI (ISVLSI)", "year": 2019 }, { "abstract": "Threshold Inverter Quantization (TIQ) for applications of system on chip (SoC) depending on CMOS flash analog to digital converter (ADC) The TIQ technique which uses two cascaded CMOS inverters as a voltage comparator. However, this TIQ method must be created to meet the latest SoC trends, which force ADCs to be integrated with another electronic circuit on the chip and focus on low power and low voltage applications. TIQ comparator reduced the impact of variations in the process, temperature, and power supply voltage. Therefore, we obtained a higher TIQ flash ADC speed and resolution. TIQ flash ADC reduced managed power dissipation. We obtain large power savings by managing the power dissipation in the comparator. Furthermore, the new comparator has a huge benefit in power dissipation and noise rejection comparative to the TIQ comparator [1] The findings indicate that the TIQ flash ADC based on Modied mux attain heavy speed transformation and has a tiny size, low power dissipation and operation of lowvoltage compared to another flash ADCs.", "author_names": [ "Ch Venkata Dharani", "J Ravi" ], "corpus_id": 212548023, "doc_id": "212548023", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "TIQ Flash ADC Design using a Low Power Multiplier Based Encoder", "venue": "International Journal of Recent Technology and Engineering", "year": 2019 }, { "abstract": "In this work a high speed flash ADC based on threshold invert quantization (TIQ) comparator has been proposed. Unlike conventional ADC resistive ladder and comparator bank has been replaced by TIQ comparator which compares the varying input with in built switching potential, 2n 1 number of TIQ requires with different switching for n bit ADC. 4 bit flash ADC has been implemented with static and dynamic TIQ; Different threshold of static TIQ is obtained by scaling the width of PMOS and NMOS individually while in dynamic TIQ input to each inverting stage acts as body voltage decide threshold voltage dynamically, threshold of TIQ is function of individual MOS width and body potential. Cadence Spectre based simulation result show that static TIQ should preferred for low power and dynamic TIQ for high speed.", "author_names": [ "Abhishek Kumar" ], "corpus_id": 214131615, "doc_id": "214131615", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of 4 Bit Flash ADC Using Static and Dynamic TIQ Comparator", "venue": "", "year": 2019 }, { "abstract": "Objective: To design and implement flash ADC for high speed operation thereby to minimise the power consumption and improve the performance efficiency. Methods: At present, there exists a variety of Analog to Digital Converter (ADC) with different architecture, sampling rates, resolutions, temperature ranges, and power consumption. The existing ADCs used in various multiple applications which include mobile communication hardware to measuring instruments. Therefore, their significant performance and working of ADCs are determined by its architecture, the commonly existing ADC design is not suitable for all applications. In order to meet the high speed operation scenario, a Flash type ADC model is proposed. Findings: Resistor ladder would be commonly used in all type of ADC circuits, but downside it consume maximum area and power. In all existing methods, the average power consumption of Flash ADC is found to be higher when compared with our methodology. This can be overcome by using threshold inverting quantization (TIQ) comparator for low power operation. Improvements: An efficient thermometer to the binary code converter is targeted for 45 nm CMOS technology that has been proposed and implemented Flash CMOS ADC Design using the CADENCE VIRTUOSO Tool. The optimal power analysis has been carried out to prove the design absolutely a low power model.", "author_names": [ "Ayyavoo Mithila", "Lavanya A", "Nithyashree A R", "Mithra T R" ], "corpus_id": 212940198, "doc_id": "212940198", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of Efficient Low Power Flash ADC Using TIQ in 45 nm Technology", "venue": "", "year": 2019 }, { "abstract": "Integral nonlinearity and differential nonlinearity are the two main performance parameters for a high speed flash analog to digital converter, which determine the accuracy of the converter. Analog to Digital Converter (ADC) circuits are designed to achieve ideal performance zero linearity. However, the linearity is unavoidable due to the process variation, operating temperature variation, and power supply voltage variation when the data converters are manufactured and used in non ideal environments. We present the new and improved transistor sizing algorithms for the Threshold Inverter Quantization (TIQ) flash comparator circuit design software package, the sizing algorithm that will results in minimal linearity for the TIQ ADCs after they are manufactured and used in non ideal environments. In comparison to the previous algorithms, the proposed new transistor sizing algorithms reduce the worst case linearity by 80% or more. In the future, when implementing ADC circuits with below 30nm CMOS FinFET technology, the TIQ flash ADC is the first candidate because only two transistors are present between the power supply rails, and the transistor sizing is based on the discrete count of fins.", "author_names": [ "Jun Hyuk Park" ], "corpus_id": 64723487, "doc_id": "64723487", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "IMPROVED TIQ FLASH ADC TRANSISTOR SIZING ALGORITHMS TO REDUCE LINEARITY ERRORS", "venue": "", "year": 2017 }, { "abstract": "In this work we introduce the flash ADC design automation (FADA) framework. It aims to reduce the design time of the threshold inverter quantization (TIQ) flash ADCs and optimizes the selected TIQ comparators of the flash ADC for differential nonlinearity (DNL) integral nonlinearity (INL) analog voltage range, power consumption and comparator noise values. We performed a survey study on flash ADCs published in the last two decades and compared them to our 10 bit single channel TIQ flash ADC. Further, it took FADA 6 h to design the 10 bit TIQ flash ADC compared to few weeks of manual design. Accordingly, FADA selected TIQ comparators set for the 10 bit TIQ flash ADC with DNL and INL values less than 0.17 LSB and 0.16 LSB, respectively, when designed in the ibm65n CMOS technology. The 10 bit TIQ flash ADC has simulated signal to noise and distortion ratio (SNDR) and spurious free dynamic range (SFDR) values of 57.2 dBs and 61 dBs, respectively. It consumes 1.67 mW of power and operates at 1.57 GSample/s. FADA provides TIQ models to optimize for high performance versus low noise TIQ flash ADCs designs.", "author_names": [ "Abdulrahman Abumurad", "Ali Ozdemir", "Kyusun Choi" ], "corpus_id": 117424348, "doc_id": "117424348", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "10 Bit Flash ADCs and Beyond: An Automated Framework for TIQ Flash ADCs Design", "venue": "Circuits Syst. Signal Process.", "year": 2019 }, { "abstract": "The comparator is the most important component in the ADC architecture. Its role is to convert an input voltage Vin into a logic 1 or 0 by comparing a reference voltage Vref with Vin. If the Vin is greater than Vref the output of the comparator is 1 otherwise 0. Commonly used comparator structure in CMOS ADC design is fully defined latch comparators. The TIQ comparator uses two cascaded CMOS inverters as a comparator for high speed conversion and low power dissipation. The aim of the project is to implement MTIQ comparator in Flash ADC by replacing ordinary comparators. It is possible to achieve higher speed, linearity, accuracy, and high resolution The project aims to make a TIQ implemented ADCs for less area and power using different compaction algorithms in layout tools like MAGIC/CADENCE.All the power Calculations are done using SPICE/CADENCE Spectre tools.", "author_names": [ "Joshua Daniel Raj J" ], "corpus_id": 218536371, "doc_id": "218536371", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "DESIGN OF MULTIPLE THRESHOLD INVERTER QUANTIZATION BASED FLASH ADC USING CUSTOM LAYOUT TOOLS", "venue": "", "year": 2018 } ]