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engineering of highly mismatched alloy with semiconductor and semi-metallic substituent's for photovoltaic applications

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current APPLIED PHYSICS 2017年第2期17卷 162-168页

作者： Ul Haq, Bakhtiar Ahmed, R. Mohamad, Mazmira Shaari, A. Rhee, JooYull AlFaify, S. Ianoun, Mohammed Benali Goumri-Said, Souraya Univ Teknol Malaysia Fac Sci Dept Phys Skudai 81310 Johor Malaysia Sungkyunkwan Univ Dept Phys Suwon 440746 South Korea King Khalid Univ Dept Phys Fac Sci AFMOL POB 9004 Abha Saudi Arabia Alfaisal Univ Dept Phys Coll Sci Riyadh 11533 Saudi Arabia

Highly mismatched alloys (HMAs) are getting a substantial interest of researchers because of holding competence of rapid change in physical properties with minor compositional change and consequently showing their potential for solar energy and photovoltaic applications. In the present density functional theory based work, we design HMAs from the extremely dissimilar GaP (semiconductor) and GaBi (semi metal). The alloying of the two compounds with unmatched electronic characteristics has triggered a rapid reduction in the energy gap of GaPBi. The energy gap is reduced by 39.3 mev for every 1% increase in Bi composition. The semiconductor behavior of GaPBi based HMAs is found to be transformed to semi metallic for replacing 64.6% of P atoms by Bi. Unlike the conventional alloys, the variation in the electronic energy gap of GaP1-xBix shows deviation from the vegard's formalism. Where the optical properties are strongly influenced with the narrowing energy gap of GaPBi. For the Bi-rich GaPBi, the notable red shift is observed in optical dielectric function and absorption spectra. Moreover, the larger atomic size of Bi has enhanced the lattice parameters of Bi-rich GaPBi. The GaPBi based HMAs with tunable energy gap in the span of 2.51 ev-0 ev and the interesting optical properties highlight them prospective materials for optoelectronic applications. (C) 2016 Elsevier B.v. All rights reserved.

关键词： Highly mismatched alloys Band engineering Optoelectronic properties DFT mBJ

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design, Fabrication, and Application of GaN-Based Micro-LED Arrays With Individual Addressing by N-Electrodes

IEEE PHOTONICS JOURNAL

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IEEE PHOTONICS JOURNAL 2017年第6期9卷 1-11页

作者： Xie, Enyuan Stonehouse, Mark Ferreira, Ricardo McKendry, Jonathan J. D. Herrnsdorf, Johannes He, Xiangyu Rajbhandari, Sujan Chun, Hyunchae Jalajakumari, Aravind v. N. Almer, Oscar Faulkner, Grahame Watson, Ian M. Gu, Erdan Henderson, Robert O'Brien, Dominic Dawson, Martin D. Univ Strathclyde Dept Phys Inst Photon Glasgow G1 1RD Lanark Scotland Univ Oxford Dept Engn Sci Oxford OX1 3PJ England Univ Edinburgh CMOS Sensors & Syst Grp Edinburgh EH9 3JL Midlothian Scotland Coventry Univ Sch Comp Elect & Math Ctr Mobil & Transport Coventry CV1 2JH W Midlands England

We demonstrate the development, performance, and application of a GaN-based micro-light emitting diode (mu LED) array sharing a common p-electrode (anode), and with individually addressable n-electrodes (cathodes). Compared to conventional GaN-based LED arrays, this array design employs a reversed structure of common and individual electrodes, which makes it innovative and compatible with n-type metal-oxide-semiconductor (NMOS) transistor-based drivers for faster modulation. Excellent performance characteristics are illustrated by an example array emitting at 450 nm. At a current density of 17.7 kA/cm(2) in direct-current operation, the optical power and small signal electrical-to-optical modulation bandwidth of a single mu LED element with 24 mu m diameter are over 2.0 mW and 440 MHz, respectively. The optimized fabrication process also ensures a high yield of working mu LED elements per array and excellent element-to-element uniformity of electrical/optical characteristics. Results on visible light communication are presented as an application of an array integrated with an NMOS driver. Data transmission at several hundred Mb/s without bit error is achieved for single-and multiple-mu LED-element operations, under an ON-OFF-keying modulation scheme. Transmission of stepped sawtooth waveforms is also demonstrated to confirm that the mu LED elements can transmit discrete multilevel signals.

关键词： GaN micro-light emitting diode array Individual addressing by n-electrodes visible light communication

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Imaging spectrometers developments in Italian space agency

Imaging spectrometers developments in Italian space agency

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International Conference on Space Optics 2008, ICSO 2008

作者： De Cosmo, v. ASI- Agenzia Spaziale Italiana ASI-Viale Liegi 26 RomaI-00198 Italy

ISBN: (纸本)9781510616219

The imaging spectroscopy is a very powerful tool for the Remote Sensing of the Solar Planets and, in particular, of the Earth. This technique permits to get not only the geometrical information but also the spectral information of the scenario under observation. The number of potential data-products obtainable in this way could be very high, useful and of benefit in several fields of Earth Observation. If these are the advantages on the other side the new dimension will increase the number of data by the number of spectral band, and for this it will increase the technical requirements, mainly, on the Instrument optical design, Focal Plane Array, Storage/Compressor Data Unit, Data Transmission etc. The instruments able to produce 3-dimensional data (cube image) are the imaging spectrometers, which depending on the way how the spectral contents is obtained, can be divided in two main categories: •The Fourier Imaging spectrometers •The Dispersing Imaging spectrometers Each one of the above categories of spectrometers has advantages and disadvantages and a choice between the two types can be made only performing a trade-off with the mission requirements. The Italian Space Agency (ASI) from long time is promoting and funding, to industrial and scientific levels, several activities covering almost all the aspects related to the imaging spectroscopy: from the applications to the instruments, from the data compressors to future hyperspectral missions. Purpose of this paper is to present the main results of the activities supported by ASI in this field with particular emphasis on the activities related to the studies and developments of new instruments. © 2017 ESA and CNES.

关键词： optical design

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A critical review of flow maps for gas-liquid flows in vertical pipes and annuli

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CHEMICAL engineering JOURNAL 2017年 326卷 350-377页

作者： Wu, Benjamin Firouzi, Mahshid Mitchell, Travis Rufford, Thomas E. Leonardi, Christopher Towler, Brian Univ Queensland Sch Chem Engn St Lucia Qld 4072 Australia Univ Queensland Sch Mech & Min Engn St Lucia Qld 4072 Australia

The accurate prediction of two-phase gas and liquid flow regimes is important in the proper design, operation and scale-up of pressure management and fluid handling systems in a wide range of industrial processes. This paper provides a comprehensive review of 3947 published experimental data points for gasliquid flow maps in vertical pipes and annuli, including a critical analysis of state-of-the-art measurement techniques used to identify bubble, slug, churn and annular flow regimes. We examine the critical factors of pipe geometry (diameters, deviation from vertical), fluid properties and flow conditions that affect the transition from one flow regime to another. The review surveys the theoretical models available to predict flow regime transitions, and we validate the accuracy of these models using the published experimental data. The most reliable flow regime transition models for upward co-current flows are analytically shown to be: (i) Barnea 1987 for dispersed bubble to bubble flow, (ii) Taitel et al. 1980 for bubble to slug flow, (iii) Barnea 1987 for slug to churn flow, and (iv) Mishima and Ishii 1984 for churn to annular flow regime transition. Moreover, based on the review we provide an outlook on the research needs and important developments in prediction of two-phase flow in vertical pipes including the use of computational fluid dynamics (CFD) techniques to simulate gas-liquid flows in vertical geometries. (C) 2017 Elsevier B.v. All rights reserved.

关键词： Experimental vertical Flow regime Flow map Regime transition CFD Co-current Counter-current Modeling

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Developing of WIMP Interfaces on Critical Platforms for Automatic Flight Control System of UAv 4

Developing of WIMP Interfaces on Critical Platforms for Auto...

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4th IEEE International Conference on Actual Problems of Unmanned Aerial vehicles developments (APUAvD)

作者： Prosvirin, D. A. Kharchenko, v. P. ANTONOV Co Kiev Ukraine Natl Aviat Univ Air Nav Syst Dept Kiev Ukraine

ISBN: (纸本)9781538618172

This article deals with developing of Windows, Icons, Menus, Pointer interfaces and model based approach to mathematical modeling process of an unmanned air vehicle flight control system. Application of modern model-based technologies for critical onboard systems development is considered. The program for unmanned air vehicle -automatic flight control system control loop simulation and visualization is developed. Use of the proposed approach allows to facilitate unmanned air vehicle onboard systems software engineering, analyze and certification process. The article concludes with a status of current research activities on the topic and a summary of the benefits provided by this approach for developing Windows, Icons, Menus, Pointer interfaces for unmanned air vehicle automatic flight control system.

关键词： model-based design Windows, Icons, Menus, Pointer critical systems automatic flight control system software engineering

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场发射X射线管电子光学系统的设计和研究

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真空科学与技术学报 2018年第3期38卷 242-245页

作者：罗登李兴辉张强胡银富刘伟冯进军王金淑北京工业大学材料科学与工程学院北京100124 北京真空电子技术研究所微波电真空器件国家级重点实验室北京100015

设计了一种基于场发射阵列阴极的X射线管结构。制备了金属尖锥阵列场发射阴极,结果表明该阴极具有良好的电子发射能力和稳定性,在阳极电压为3400 v的条件下,发射电流达1.46 mA,电流密度达516.4 mA/cm^2,适合应用于X射线管中。利用CST粒... 详细信息

设计了一种基于场发射阵列阴极的X射线管结构。制备了金属尖锥阵列场发射阴极,结果表明该阴极具有良好的电子发射能力和稳定性,在阳极电压为3400 v的条件下,发射电流达1.46 mA,电流密度达516.4 mA/cm^2,适合应用于X射线管中。利用CST粒子工作室仿真软件对X射线管的电子光学系统进行计算,得到了可行的结构方案,结构由阵列阴极、聚焦极和阳极组成,阴极与聚焦极等电位,该结构中阴极面积为10 mm×2 mm,总发射电流约为10 mA,满足X射线管的发射要求。阳极电子束斑大小为1 mm×1 mm,可得到有效焦点大小为0.58 mm×1 mm的X射线。研究为进一步制造高分辨率的场发射X射线管打下了基础。

关键词：场发射 x射线管电子光学束斑

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System thermalhydraulics for design basis accident analysis and simulation: Status of tools and methods and direction for future R&D

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NUCLEAR engineering AND design 2017年第Feb.期312卷 12-29页

作者： Bestion, D. Commissariat Energie Atom & Energies Alternat DEN STMF LMES DM2S 17 Rue Martyrs F-38054 Grenoble France

System thermalhydraulic investigations of design Basis Accident require several tools and methods including the Process Identification and Ranking Table, the scaling, experiment analysis, modelling, code development, code validation and verification, and Uncertainty Quantification. This paper intends to give an overview of these methods and tools showing what the state of the art is, and presenting some recent advances. Recommendations are made with future direction for R&D including the need of new advanced experiments and instrumentation, and the future role of CFD and multi-scale analyses. For many people it is not clear what current system codes are, and what they can be. Then the main characteristics of these codes are recalled and propositions are made to clarify the code capabilities and limitations and to improve the knowledge of the conditions for a correct application of the codes for safety in a Best Estimate Plus Uncertainty approach. Also, the on-going developments of 3-field models and Transport of Interfacial Area are summarized and associated experimental needs are identified. The growing role of 3D modelling of reactor core and Pressure vessel requires additional experimental data for a proper validation. CFD in open medium also contributes to investigations when 3D geometrical aspects play an important role. Recent activities performed in the OECD-NEA Working Group for Analysis and Management of Accidents is summarized and recent applications of two-phase CFD to boiling flows and two-phase PTS scenarios are reported. The role of a multi-scale approach for safety issues is illustrated with the LOCA transients in LWRs. Attention is focused on the need of specific validation experiments and of consolidated uncertainty methods for both system codes and CFD codes. (C) 2016 Elsevier B. v. All rights reserved.

关键词： System thermalhydraulic BEPU Scaling Multi-scale simulation DBA

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A comparative multi-disciplinary policy review in wind energy developments in Europe

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INTERNATIONAL JOURNAL OF SUSTAINABLE ENERGY 2017年第8期36卷 754-774页

作者： Mytilinou, v. Kolios, A. J. Di Lorenzo, G. Cranfield Univ Cranfield Energy Cranfield MK43 0AL Beds England

Over recent decades, European Union countries have committed to increasing their electricity production from renewable energy sources (RESs). Wind energy plays a significant role in a sustainable future. This paper presents a political, economic, social, technological, legal and environmental analysis. Although these countries have made many improvements in their legal frameworks aiming to attract investors and boost the RE sector, there are still challenges. The UK focuses on offshore wind energy, adjusts the economic strategy and changes the legislation context. Germany has the healthiest economic conditions, as it keeps following its initiative to design a new programme for an energy transition from conventional to RESs with emphasis on the onshore. Greece has only a few installations and much room for development but needs to make further changes in the legislation and economy so as to attract more investors in the long term. The purpose of this research is to analyse, highlight and discuss vital aspects of these countries as well as the European environment, with reference to their current wind energy activities. Ultimately, it attempts to give a wider perspective and to serve as a guide for future studies on the wind energy sector.

关键词： PESTLE wind energy multi-disciplinary review

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Software design of a Railway Signal Monitoring System based on optical Fiber Sensing

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INTERNATIONAL JOURNAL OF ONLINE engineering 2018年第8期14卷 134-146页

作者： Ma, Chun-ying Li, Biqing Henan Engn Res Ctr Rail Transit Intelligent Secur Zhengzhou 451460 Henan Peoples R China Hezhou Univ Sch Informat & Commun Engn Hezhou Guangxi 542899 Peoples R China

The current railway track circuit monitoring system is prone to disturbances that can result in accidents. Meanwhile, basic signaling equipment is slow and cannot achieve satisfactory real-time data acquisition speed. This study aims to solve the aforementioned problems by designing an online monitoring and management platform for railway signal infrastructure, which is based on the graphical programming language LabvIEW. Online monitoring and management of railways' basic signaling equipment allow real-time collection and communication of various signal equipment data. These processes also enable signal processing, chart display, acousto-optic alarm, user authority management, data storage, data query analysis, and report printing. The test results show that the LabvIEW-based basic signaling equipment for monitoring and managing railway systems can transmit data correctly and steadily, thereby resulting in convenient and ideal operation.

关键词： track circuit online monitoring LabvIEW peak finding detection

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Development of a ring cavity-based fibre optic sensor for MR-compatible medical sensing applications

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IOP Conference Series: Materials Science and engineering 2019年第1期499卷

作者： K Bhavsar v viswambaran J Johny M Kailasnath A Melzer R Prabhu School of Engineering Robert Gordon University Aberdeen UK International School of Photonics Cochin University of Science & Technology Kochi India Institute for Medical Science and Technology University of Dundee Dundee UK

Advances in robotic systems and rapid developments in minimally invasive surgery (MIS) have made their use possible in the operating room due to many distinct advantages offered by MIS over conventional surgical procedures. The constant increase of medical examinations, surgeries and surgical interventions using intraoperative guidance with magnetic resonance imaging (MRI) has promoted research on new sensors to be applied in this scenario. However, due to the challenging environment under MRI system limits the applicability of materials and traditional electronic sensors. optical fibres are small in size, chemically inert, immune to electromagnetic interference and offer the real-time in vivo multi-parameter measurement capability. Herein, we report a ring cavity-based fibre optic sensor design using MR-compatible polymer material. optical fibres were used to excite surface resonance modes (SRM) of the ring cavity-based sensor. The paper reports initial investigations on ring cavity based MR-compatible fibre optic sensor design. Computational simulations were carried out to study the effect of structural and material parameters on the sensor design. Ring cavity was developed using polymethyl methacrylate. Developed ring cavity will be used to develop the MR-compatible fibre optic sensor for medical applications.

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