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An aluminum nitride photoconductor for X-ray detection

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Journal of Semiconductors 2012年第10期33卷 25-28页

作者：王新建宋航李志明蒋红黎大兵缪国庆陈一仁孙晓娟 State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and Physics Graduate University of the Chinese Academy of Sciences

An AlN photoconductor for X-ray detection has been fabricated,and its response to X-ray irradiation intensity is *** photoconductor has a very low leakage current,less than 0.1 nA at an applied voltage of 100 V in the absence of X-ray *** photocurrent measurement results clearly reveal that the photocurrent is proportional to the square root of the X-ray irradiation intensity,and under relatively high irradiation the photocurrent can reach values one order of magnitude larger than the dark current when a voltage of 100 V is applied across the AlN *** using the ABC model the dependence of the photocurrent on the X-ray irradiation intensity is analyzed,and a reasonable interpretation of the physical mechanism is obtained.

关键词： AlN photoconductor X-ray detection recombination

Effect of Manufacturing Errors on Static Characteristics of Externally Pressurized Spherical Air Bearings

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Chinese Journal of Mechanical Engineering 2009年第6期22卷 896-902页

作者： REN Di WANG Zuwen YANG Qingjun BAO Gang School of Mechanical and Electrical Engineering Harbin Institute of Technology Harbin 150001 China Transportation and Logistics Engineering College Dalian Maritime University Dalian 116026 China

Externally pressurized spherical air bearings are the key component of the three-axis air bearing table, and the manufacturing errors of the bearing affects the performance of the air bearing table. However, the manufacturing errors are unavoidable, and the pursuit to enhance the manufacturing accuracy will increase the cost greatly. In order to provide some theoretical guideline for the tolerance choice in the design of the externally pressurized spherical air bearings with inherent compensation, the effects of several manufacturing errors on the static characteristics of the air bearing are studied. Due to the complex geometry of the computational domain, an unstructured meshing technology is used for mesh generation. A finite-volume method is adopted to discretize the three-dimensional steady-state compressible Navier-Stokes equations. A modified SIMPLE algorithm which is suitable for compressible flows is applied to solve the discretized governing equations. The effects of the dimension error and the roundness error of the ball head and the ball socket on the static characteristics are investigated. The investigation result shows that the positive dimension error and the oblate spheroid-type roundness error of the ball head as well as the negative dimension error and the prolate spheroid-type roundness error of the ball socket can improve the bearing capacity and static stiffness of the air bearings by reducing the mass flow. The calculation method proposed in this paper fits well for the general principle, which can be extended to the characteristics analysis of other air bearings.

关键词： externally pressurized spherical air bearings manufacturing errors bearing capacity static stiffness mass flow

Lattice Boltzmann model for shallow water in curvilinear coordinate grid

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Journal of Hydrodynamics 2017年第2期29卷 251-260页

作者：赵庄明黄平李少钿 South China institute of Environmental Sciences the Ministry of Environmental Protection of PRC Department of Environmental Science School of Environmental Science and EngineeringSun Yat-sen University

In this study, a multi-relaxation time lattice Boltzmann model for shallow water in a curvilinear coordinate grid is developed using the generalized form of the interpolation supplemented lattice Boltzmann method. The Taylor-Colette flow tests show that the proposed model enjoys a second order accuracy in space. The proposed model is applied to three types of meandering channels with 180°, 90°and 60° consecutive bends. The numerical results demonstrate that the simulated results agree well with previous computational and experimental data. In addition, the model can achieve the acceptable accuracy in terms of the water depth and the depth-averaged velocities for shallow water flows in curved and meandering channels over a wide range of bend angles.

关键词： Curvilinear coordinate lattice Boltzmann method meandering flow multi-relaxation-time model shallow water

Effect of coefficient of restitution in Euler-Euler CFD simulation of fluidized-bed hydrodynamics

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Particuology 2014年第4期12卷 170-177页

作者： Chanchal Loha Himadri Chattopadhyay Pradip K.Chatterjee Thermal Engineering Division CSIR-Central Mechanical Engineering Research InstituteDurgapur 713209India Department of Mechanical Engineering Jadavpur UniversityKolkata 700032India

Collision between particles plays an important role in determining the hydrodynamic characteristics of gas-solid flow in a fluidized bed. In the present work, earlier work （Loha, Chattopadhyay, ＆ Chatterjee, 2013） was extended to study the effect of the elasticity of particle collision on the hydrodynamic behavior of a bubbling fluidized bed filled with 530-~m particles. The Eulerian-Eulerian two-fluid model was used to simulate the hydrodynamics of the bubbling fluidized bed, where the solid-phase properties were calculated by applying the kinetic theory of granular flow. To investigate the effect of the elasticity of particle collision, different values of the coefficient of restitution were applied in the simulation and their effects were studied in detail. Simulations were performed for two different solid-phase wall boundary conditions. No bubble formation was observed for perfectly elastic collision. The bubble formation started as soon as the coefficient of restitution was set below 1.0, and the space occupied by bubbles in the bed increased with a decrease in the coefficient of restitution. Simulation results were also compared with experimental data available in the literature, and good agreement was found for coefficients of restitution of 0.95 and 0.99.

关键词： Coefficient of restitution Fluidization Hydrodynamics computational fluid dynamics Euler-Euler approach

CFD-based optimization and design of multi-channel inorganic membrane tubes

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Chinese Journal of Chemical Engineering 2016年第10期24卷 1375-1385页

作者： Zhao Yang Jingcai Cheng Chao Yang Bin Liang College of Chemical Engineering Sichuan University Chengdu 610065China Key Laboratory of Green Process and Engineering Institute of Process EngineeringCASBeijing 100190China

As a major configuration of membrane elements,multi-channel porous inorganic membrane tubes were studied by means of theoretical analysis and *** optimization of a cylindrical 37-channel porous inorganic membrane tube was studied by increasing membrane filtration area and increasing permeation efficiency of inner *** optimal ratio of the channel diameter to the inter-channel distance was proposed so as to increase the total membrane filtration area of the membrane *** three-dimensional computational fluid dynamics(CFD) simulation was conducted to study the cross-flow permeation flow of pure water in the 37-channel ceramic membrane tube.A model combining Navier–Stokes equation with Darcy's law and the porous jump boundary conditions was *** relationship between permeation efficiency and channel locations,and the method for increasing the permeation efficiency of inner channels were *** novel multichannel membrane configurations with more permeate side channels were put forward and evaluated.

关键词： Inorganic membrane Multi-channel tube computational fluid dynamics (CFD)Simulation Optimization

Modeling of a triple reduced surface field silicon-on-insulator lateral double-diffused metal–oxide–semiconductor field-effect transistor with low on-state resistance

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Chinese Physics B 2016年第2期25卷 430-435页

作者：王裕如刘祎鹤林兆江方冬李成州乔明张波 State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China (UESTC) institute of Electronic and Information Engineering in Dongguan UESTC

An analytical model for a novel triple reduced surface field（RESURF） silicon-on-insulator（SOI） lateral doublediffused metal–oxide–semiconductor（LDMOS） field effect transistor with n-type top（N-top） layer, which can obtain a low on-state resistance, is proposed in this paper. The analytical model for surface potential and electric field distributions of the novel triple RESURF SOI LDMOS is presented by solving the two-dimensional（2D） Poisson＇s equation, which can also be applied to single, double and conventional triple RESURF SOI structures. The breakdown voltage（BV） is formulized to quantify the breakdown characteristic. Besides, the optimal integrated charge of N-top layer（Q_（ntop）） is derived, which can give guidance for doping the N-top layer. All the analytical results are well verified by numerical simulation results,showing the validity of the presented model. Hence, the proposed model can be a good tool for the device designers to provide accurate first-order design schemes and physical insights into the high voltage triple RESURF SOI device with N-top layer.

关键词： analytical model triple reduced surface field (RESURF) silicon-on-insulator (SOI) n-type top (N-top) layer

Layout design and application of 4D-printing bio-inspired structures with programmable actuators

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Bio-Design and Manufacturing 2022年第1期5卷 189-200页

作者： Siyuan Zeng Yixiong Feng Yicong Gao Hao Zheng Jianrong Tan State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China Hangzhou Innovation institute Beihang UniversityHangzhou 310000China

Four-dimensional(4D)printing is an advanced form of three-dimensional(3D)printing with controllable and programmable shape transformation over *** are used as a controlling factor with multi-stage shape recovery,with emerging opportunities to customize the mechanical properties of bio-inspired *** print pattern of shape memory polymer(SMP)fbers strongly afects the achievable resolution,and consequently infuences several other physical and mechanical properties of fabricated ***,the deformations of bio-inspired structures due to actuator layout are more complex because of the presence of the coupling of multi-directional *** this study,the initial structure was designed from closed-shell behavior and divided into a general unit and actuator unit,the latter responsible for driving the *** stress confrontation between the actuator and the general unit was considered in the layout thermodynamic model,in order to eliminate the transformation produced by the uncontrolled shape memory behavior of the general *** critical and efective strategies for the layout design of actuators were proposed and then applied to achieve the desired accurate deformation of 3D-printed bilayer ***,the proposed approach was validated and adopted for fabricating a complex shell-like gripper structure.

关键词： Bio-inspired structure Layout design Programmable actuators Bilayer structure 4D printing

给定活动导叶开口水泵水轮机模型泵工况驼峰现象流动分析（英文）

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Journal of Zhejiang University-Science A(applied Physics & Engineering) 2015年第11期16卷 851-863页

作者： De-you LI Ru-zhi GONG Hong-jie WANG Wen-wen FU Xian-zhu WEI Zhan-sheng LIU School of Energy Science and Engineering Harbin Institute of Technology State Key Laboratory of Hydro-Power Equipment Harbin Institute of Large Electrical Machinery

目的:探索水泵水轮机泵工况在超负荷工况(1.24φBEP)、最优工况(1.00φBEP)、靠近最优工况(0.90φBEP)、驼峰区工况(0.65φBEP)以及低负荷工况(0.45φBEP)的流动特性,期望获得流动特性变化规律,揭示驼峰特性形成机理。方法:对某一水泵... 详细信息

目的:探索水泵水轮机泵工况在超负荷工况(1.24φBEP)、最优工况(1.00φBEP)、靠近最优工况(0.90φBEP)、驼峰区工况(0.65φBEP)以及低负荷工况(0.45φBEP)的流动特性,期望获得流动特性变化规律,揭示驼峰特性形成机理。方法:对某一水泵水轮机模型,采用剪切压力传输(SST)k-ω湍流模型进行三维定常数值模拟,在实验验证的基础上:1.在曲面坐标系中,分析由叶片形状所引起的各个工况叶片进出口边在周向和叶片方向上的分布规律;2.运用经典欧拉理论分析叶片进出口边液流角变化对各个工况的欧拉水头的影响;3.通过水力损失分析,获得不同部件各个工况损失变化规律。结论:1.转轮叶片进出水边的液流角随着叶片方向在不同流量工况分布下具有明显差异,导致转轮流道不同程度流动分离;2.运用经典欧拉理论得出驼峰区工况点出口角液流的减小与入口液流的增加是驼峰特性产生的主要原因之一;3.通过损失分析,确定泵工况损失主要在转轮和双列叶栅中,得出转轮部分损失是驼峰特性形成的主要原因之一;4.综合分析,驼峰特性是由该工况欧拉动量的减小和转轮部分损失的增加共同作用的结果。

关键词：水泵水轮机流动分析液流角水力损失驼峰区

Recent advances in catalytica symmetric Buchner reaction

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Chinese Chemical Letters 2023年第12期34卷 87-92页

作者： Chong-Yang Shi Guang-Yu Zhu Yin Xu Ming-Yu Teng Long-Wu Ye College of Chemistry and Chemical Engineering Yunnan Normal UniversityKunming 650500China Key Laboratory of Chemical Biology of Fujian Province State Key Laboratory of Physical Chemistry of Solid Surfacesand College of Chemistry and Chemical EngineeringXiamenUniversity.Xiamen361005China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Bichner reaction,as a unique type of expansive dearomatization,has become a practical strategy for the straightforward assembly of valuable functionalized cycloheptatrienes from ubiquitous aromatic *** the asymmetric version has been investigated since the early 1990s,enantioselective Bichner reaction is still limited by the catalyst type and substrate *** review aims to propose the limitation and possible development direction of this field by summarizing the evolution of catalytic asymmetric Bichner reaction,which is organized on the basis of intra-and intermolecular *** the different metal carbene precursors,the reactions are further classified by carbene sources.

关键词： Bichner reaction Diazo compounds Metal carbenes Cycloheptatrienes Dearomatization reactions