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Design and Analysis of S-CO_2 Cycle and Radial Turbine for SOFC Vehicle Waste-Heat Recovery

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Journal of Thermal Science 2019年第3期28卷 559-570页

作者： XIA Liu LI Xuesong SONG jian REN Xiaodong gu Chunwei Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power Engineering Tsinghua University Clean Energy Processes (CEP) Laboratory Department of Chemical Engineering Imperial College London

Solid oxide fuel cell(SOFC) vehicles are considered to have broad prospects for development, and the high operating temperature of SOFC results in great potential for waste-heat recovery. Many concepts for utilizing waste heat of SOFC have been suggested and studied, and most of them directly couple an SOFC to a gas turbine, which require the SOFC to operate at an elevated pressure and make the system less flexible and thus harder to operate. In recent years, with the development of turbine and heat exchanger technology, the supercritical carbon dioxide(S-CO_2) power cycle has raised widespread attractions for the waste recovery. This study explores the potential of S-CO_2 Brayton cycle to realize waste-heat recovery for an SOFC vehicle. The SOFC can operate at atmospheric pressure, and the hybrid system is easier to operate than the directly coupled systems. In this paper, a simple recuperated S-CO_2 Brayton cycle is proposed and the key component, radial inflow turbine is designed and focused. The flow state of the designed turbine is analyzed in detail based on computational fluid dynamics(CFD) numerical simulation. Five cases with different impeller tip clearances are numerically simulated to study its influence on the turbine performance. In addition, off-design performance analysis of the radial inflow turbine is conducted considering the temperature fluctuation of SOFC in practical applications.

关键词： SOFC waste-heat recovery supercritical carbon dioxide radial turbine

Efficient detection methods for amplify-and-forward relay-aided device-to-device systems with full-rate space-time block code

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Frontiers of Information Technology & Electronic Engineering 2017年第6期18卷 788-795页

作者： Kang-li ZHANG Cong ZHANG Fang-lin gu jian WANG College of Electronic Science and Engineering National University of Defence Technology School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Relay-aided device-to-device (D2D) communication is a promising technology for the next-generation cellular network. We study the transmission schemes for an amplify-and-forward relay-aided D2D system which has multiple antennas. To circumvent the prohibitive complexity problem of traditional maximum likelihood (ML) detection for full-rate space-time block code (FSTBC) transmission, two low-complexity detection methods are proposed, i.e., the detection methods with the ML-combining (MLC) algorithm and the joint conditional ML (JCML)detector. Particularly, the method with the JCML detector reduces detection delay at the cost of more storage and performs well with parallel implementation. Simulation results indicate that the proposed detection methods achieve a symbol error probability similar to that of the traditional ML detector for FSTBC transmission but with less complexity, and the performance of FSTBC transmission is significantly better than that of spatial multiplexing transmission. Diversity analysis for the proposed detection methods is also demonstrated by simulations.

关键词： Device-to-device Relay Detection Full-rate space-time block code

A new radar stealth design excited by ^(210)Po and ^(242)Cm

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Nuclear Science and Techniques 2022年第6期33卷 45-53页

作者： Jin-jian Yuan gui-Ping Meng Min gu Run-Sheng Huang School of Physics Nanjing UniversityNanjing 210093China

Open plasma stealth technology excited by radionuclides is known to have several problems:(1)owing to disturbance from airflow,the plasma distribution is unstable.(2)The plasma is highly dependent on the atmosphere;therefore,it is difficult to modulate in target stealth.(3)Concerns regarding radiation harassment prevent the application of this *** avoid these problems,an enclosed plasma stealth method is *** simulation on an infinite conducting plate,this method was found to effectively solve the above concerns,which may offer a new approach for the practical application of plasma stealth technology excited by radionuclides,especially for small-satellite stealth because of its lightweight and selfprovided plasma.

关键词： Radiation ionization αDecay particles Plasma film Radar stealth technology

Metal–Organic Framework‑Based Photodetectors

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Nano-Micro Letters 2024年第11期16卷 675-703页

作者： Jin‑Biao Zhang Yi‑Bo Tian Zhi‑Gang gu jian Zhang State Key Laboratory of Structural Chemistry Structure of MatterFujian Institute of ResearchChinese Academy of SciencesFuzhouFujian 350002People’s Republic of China College of Chemistry and Materials Science Fujian Nornal UniversityFuzhou 350007FujianPeople’s Republic of China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108FujianPeople’s Republic of China University of Chinese Academy of Science Beijing 100049People’s Republic of China

The unique and interesting physical and chemical properties of metal–organic framework(MOF)materials have recently attracted extensive attention in a new generation of photoelectric *** this review,we summarized and discussed the research progress on MOF-based *** methods of preparing MOF-based photodetectors and various types of MOF single crystals and thin film as well as MOF composites are introduced in ***,the photodetectors applications for X-ray,ultraviolet and infrared light,biological detectors,and circularly polarized light photodetectors are ***,summaries and challenges are provided for this important research field.

关键词： Metal-organic frameworks Semiconductor Photodetectors

Numerical simulation study on the mold strength of magnetic mold casting based on a coupled electromagnetic-structural method

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China Foundry 2024年第5期21卷 577-587页

作者： Wei-li Peng jian-hua Zhao Cheng gu Ya-jun Wang College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China

The properties of the magnetic mold in magnetic mold casting directly determine the quality of the final cast *** this study,the magnetic mold properties in magnetic mold casting,were studied utilizing a coupled electromagnetic-structural method through numerical *** study investigated key factors including equivalent stress,the distribution of tensile and compressive stresses,and the area ratio of tensile *** compared molds made entirely of magnetic materials with those made partially of magnetic *** results indicate that as current increases from 4 A to 8 A,both the initial magnetic mold and the material-replaced magnetic mold initially show an increasing trend in equivalent stress,tensile-compressive stress,and the area ratio of tensile stress,peaking at 6 A before *** material replacement,the area ratio of tensile stress at 6 A decreases to 19.84%,representing a reduction of 29.72%.Magnetic molds comprising a combination of magnetic and non-magnetic materials exhibit sufficient strength and a reduced area ratio of tensile stress compared to those made entirely from magnetic *** study provides valuable insights for optimizing magnetic mold casting processes and offers practical guidance for advancing the application of magnetic molds.

关键词： magnetic mold casting coupled electromagnetic-structural method numerical simulation stress analysis

Diamond-based electron emission:Structure,properties and mechanisms

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Chinese Physics B 2024年第9期33卷 165-177页

作者： Liang-Xue gu Kai Yang Yan Teng Wei-Kang Zhao Geng-you Zhao Kang-Kang Fan Bo Feng Rong Zhang you-Dou Zheng jian-Dong Ye Shun-Ming Zhu Kun Tang Shu-Lin gu School of Electronic Science and Engineering Nanjing UniversityNanjing 210046China

Diamond has an ultrawide bandgap with excellent physical properties,such as high critical electric field,excellent thermal conductivity,high carrier mobility,*** with a hydrogen-terminated(H-terminated)surface has a negative electron affinity(NEA)and can easily produce surface electrons from valence or trapped electrons via optical absorption,thermal heating energy or carrier transport in a PN *** NEA of the H-terminated surface enables surface electrons to emit with high efficiency into the vacuum without encountering additional barriers and promotes further development and application of diamond-based emitting *** article reviews the electron emission properties of H-terminated diamond surfaces exhibiting NEA *** electron emission is induced by different physical *** advancements in electron-emitting devices based on diamond are also ***,the current challenges and future development opportunities are discussed to further develop the relevant applications of diamond-based electronemitting devices.

关键词： diamond negative electron affinity(NEA) PN junction electron emission

Pilot power based rate control in CDMA 2000 1x EV-DO Rev-A

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The Journal of China Universities of Posts and Telecommunications 2008年第1期15卷 118-122页

作者： LIU Xiao-feng gu jian YANG Hong-wen Wireless communication Center Beijing University of Posts andTelecommunications Beijing 100876 China

This article proposes a new algorithm to improve the rate control efficiency of enhanced reverse link medium access control （RLMAC） in the code division multiple access （CDMA） 1x EV-DO release A（Rev. A） system. The new algorithm brings reverse access terminal （AT） pilot power to the RLMAC rate control procedure and makes it easier for a low pilot power user to increase its data rate when the system is slightly loaded and harder to decrease its date rate when the system is heavily loaded. Numerical results of system level simulations show that the new algorithm can bring higher system throughput, lower AT transmission power, and lower system load.

关键词： RLMAC CDMA 1x EV-DO pilot power rate control

Personalization for Massive Product Innovation Using Open Architecture

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Chinese Journal of Mechanical Engineering 2018年第2期31卷 12-24页

作者： Qing-Jin Peng Yun-Hui Liu jian Zhang Pei-Hua gu Department of Mechanical Engineering University of Manitoba Department of Mechatronics Engineering Shantou University

Product innovation is creation of new concepts to plan and realize technological and functional details in the product to satisfy market and customer needs. One of the key drivers to product innovation is reactions of the product to users’ needs. Product innovation needs a cognitive design method based on needs of variant users for the product personalization. In this paper, an open concept is introduced to provide ways to meet user’s individual need in product lifespan. It is for industries to propose product concepts based on open sources, develop and support the product on the public capability. Using the open concept in the product architecture, called open?architecture product(OAP), can improve the product personalization leading to massive product innovation. To promote this promise of the OAP, effective methods are discussed for the OAP development. This paper introduces research on OAPs using adaptable design methods to meet product personalization. Adaptable design is based on the modular structure for product adaptability using function modules and adaptable interfaces. The proposed method provides solutions for planning modules and implementation of OAPs. Methods of OAP module planning, detail and interface design are described for transformation of product concepts into physical structures. A multiple?purpose electrical car is developed in a case study to show effectiveness of the proposed method.

关键词： Product design Personalization Massive innovation Open architecture Adaptable design

Micro-scale Cellular Automaton Modeling of Interface Evolution During Reaustenitization from Pearlite Structure in Steels

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Acta Metallurgica Sinica(English Letters) 2018年第7期31卷 713-722页

作者： Gang Shen Cheng-Wu Zheng jian-Feng gu Dian-Zhong Li Institute of Materials Modification and Modelling School of Materials Science and Engineering Shanghai Jiao Tong University Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Materials Genome Initiative Center Shanghai Jiao Tong University Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong University

A modified cellular automaton model is developed to depict the interface evolution inside the cementite plus ferrite lamellar microstructures during the reaustenitization of a pearlite steel. In this model, migrations of both the austenite- ferrite and austenite-cementite interfaces coupled with the carbon diffusion and redistribution are integrated. The capil- laxity effect derived from local interface curvatures is also carefully considered by involving the concentration given by the phase diagram modified by the Gibbs-Thomson effect. This allows the interface evolution from a transient state to a steady state under different annealing conditions and various interlamellar spacings to be simulated. The proposed cellular automaton approach could be readily used to describe the kinetics of austenite formation from the lamellar pearlites and virtually reveal the kinematics of the moving interfaces from the microstructural aspect.

关键词： Austenite formation Lamellar pearlite Interface evolution Cellular automaton Microstructural modeling