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Hot Deformation and Dynamic Recrystallization Behavior of Austenite-Based Low-Density Fe–Mn–Al–C Steel

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Acta Metallurgica Sinica(English Letters) 2016年第5期29卷 441-449页

作者： Ya-Ping Li ren-Bo Song Er-Ding Wen Fu-Qiang yang School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China R&D Center BAIC Motor Corporation LTDBeijing 101300China

The hot deformation and dynamic recrystallization （DRX） behavior of austenite-based Fe-27Mn-ll.5A1- 0.95C steel with a density of 6.55 g cm-3 were investigated by compressive deformation at the temperature range of 900-1150 ℃ and strain rate of 0.01-10 s-1. Typical DRX behavior was observed under chosen deformation conditions and yield-point-elongation-like effect caused by DRX of 6-ferrite. The flow stress characteristics were determined by DRX of the 6-ferrite at early stage and the austenite at later stage, respectively. On the basis of hyperbolic sine function and linear fitting, the calculated thermal activation energy for the experimental steel was 294.204 kJ mo1-1. The occurrence of DRX for both the austenite and the 6-ferrite was estimated and plotted by related Zener-Hollomon equations. A DRX kinetic model of the steel was established by flow stress and peak strain without considering dynamic recovery and 6-ferrite DRX. The effects of deformation temperature and strain rate on DRX volume fraction were discussed in detail. Increasing deformation temperature or strain rate contributes to DRX of both the austenite and the 6-ferrite, whereas a lower strain rate leads to the austenite grains growth and the 6-ferrite evolution, from banded to island-like structure.

关键词： Fe-Mn-AI-C steel Hot deformation Dynamic recrystallization Yield-point-elongation-likeeffect

Reliability evaluation of tidal and wind power generation system with battery energy storage

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Journal of Modern Power Systems and Clean Energy 2016年第4期4卷 636-647页

作者： Mingjun LIU Wenyuan LI Juan YU Zhouyang ren Ruilin XU State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqing 400030China Chongqing Electric Power Research Institute Chongqing 401123China

This paper presents a method for reliability evaluation of a hybrid generation system of wind and tidal powers with battery energy *** a system may widely exist in coastal areas and islands in the future.A chronological multiple state probability model of tidal power generation system(TPGS)considering both forced outage rate(FOR)of the TPGS and random nature of tidal current speed is *** the evaluation of FORs of TPGS and WPGS(wind power generation system),the delivered power related failure rates of power electronic converters for TPGS and WPGS are considered.A chronological power output model of battery energy storage system(BESS)is derived.A hybrid system of tidal and wind generation powers with a BESS is used to demonstrate the effectiveness of the presented *** case studies,the effects of various parameters on the system reliability are investigated.

关键词： Generation system Tidal power generation Wind power generation Battery energy storage Reliability evaluation

Pulsating magneto-dipole radiation of a quaking neutron star powered by energy of Alfvn seismic vibrations

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Research in Astronomy and Astrophysics 2011年第9期11卷 1085-1092页

作者： Sergey Bastrukov Jun-Wei Yu ren-Xin Xu Irina Molodtsova State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China Joint Institute for Nuclear Research 141980 Dubna Russia

We compute the characteristic parameters of the magneto-dipole radiation of a neutron star undergoing torsional seismic vibrations under the action of Lorentz restoring force about an axis of a dipolar magnetic field experiencing decay. After a brief outline of the general theoretical background of the model of a vibration-powered neutron star, we present numerical estimates of basic vibration and radiation characteristics, such as frequency, lifetime and luminosity, and investigate their time dependence on magnetic field decay. The presented analysis suggests that a gradual decrease in frequencies of pulsating high-energy emission detected from a handful of currently monitored AXP/SGR-like X-ray sources can be explained as being produced by the vibration-powered magneto-dipole radiation of quaking magnetars.

关键词： neutron stars -- torsion Alfv6n vibrations -- vibration powered radiation -- magnetic field decay -- magnetars

Thermo-hydraulic experimental validation of an integrated modular small reactor operating in full power natural circulation

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Science China(Technological Sciences) 2014年第1期57卷 1-8页

作者： yanG XingTuan ren Cheng LIU ZhiYong TU JiYuan JIANG ShengYao Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Institute of Nuclear and New Energy Technology Tsinghua University

Small reactors have become a new hotspot of international nuclear energy *** nuclear heating reactor(NHR)technology developed by Tsinghua University is an important multipurpose small reactor solution with features such as high integration,modular design and full power natural circulation.A new small reactor based on the existing NHR-200 reactor was developed by the Institute of Nuclear and New Energy Technology of Tsinghua University.A full-scale natural circulation test loop with the same operating parameters as the actual reactor was built in order to experimentally validate the natural circulation ability of the reactor primary loop and heat-transfer ability of fuel assemblies and heat *** results are given in detail,including parameter validation of the reactor primary loop,flow rules of the natural circulation and heat-transfer coefficients of heaters and heat exchangers,which can be directly used in the actual reactor as a reference for optimization ***,a characteristic parameter k is proposed to represent the natural circulation ability of a *** using the new data arrangement method in the form of parameter k,comprehensive experimental results of the natural circulation can be represented by a simple integrated *** work in this paper is of importance in broadening application fields and pushing forward commercialization of the NHR type reactors.

关键词： small reactor natural circulation validation experiment

Tetra(acetylacetonato) tin(Ⅳ) as new catalyst for polytrimethylene terephthalate synthesis

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Chinese Chemical Letters 2010年第3期21卷 357-360页

作者： Shu Yong Jia Yu Rong ren Gong Ying Wang College of Chemistry Jilin Normal UniversitySiping 136000China Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China

Chelate tetra(acetylacetonato) tin(Ⅳ) was prepared and used as catalyst for polytrimethylene terephthalate *** exhibited higher catalytic activity than tetrabutyl titanate,butyltinhydroxide oxide and dibutyltin *** in reaction time, content of terminal carboxyl group,color intensity and increase in intrinsic viscosity were *** unique molecular structure can be considered as factor remarkably improving the catalytic activity of tetra(acetylacetonato) tin(Ⅳ).

关键词： Tetra(acetylacetonato) tin(Ⅳ) Polytrimethylene terephthalate Terephthalic acid 1,3-Propanediol

Numerical study on the turbulent mixing of planar shock-accelerated triangular heavy gases interface

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Acta Mechanica Sinica 2018年第5期34卷 855-870页

作者： Wei-Gang Zeng Jian-Hua Pan Yu-Xin ren Yu-Tao Sun Department of Engineering Mechanics School of AerospaceTsinghua UniversityBeijing 100084China Institute of Applied Physics and Computational Mathematics Beijing 100094China

The interaction of a planar shock wave with a triangle-shaped sulfur hexafluoride (SF6) cylinder surrounded by air is numerically studied using a high resolution finite volume method with minimum dispersion and controllable dissipation *** vortex dynamics of the Richtmyer-Meshkov instability and the turbulent mixing induced by the KelvinHelmholtz instability are discussed.A modified reconstruction model is proposed to predict the circulation for the shock triangular gas-cylinder interaction *** typical stages leading the shock-driven inhomogeneity flow to turbulent mixing transition are *** the decoupled length scales and the broadened inertial range of the turbulent kinetic energy spectrum in late time manifest the turbulent mixing transition for the present *** analysis of variable-density energy transfer indicates that the flow structures with high wavenumbers inside the Kelvin-Helmholtz vortices can gain energy from the mean flow in ***,small scale flow structures are generated therein by means of nonlinear ***,the occasional 'pairing' between a vortex and its neighboring vortex will trigger the merging process of vortices and,finally,create a large turbulent mixing zone.

关键词： Richtmyer-Meshkov instability Kelvin-Helmholtz instability Length scale Turbulent mixing

Hardware-in-the-loop simulation for the contact dynamic process of flying objects in space

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Science China(Technological Sciences) 2016年第8期59卷 1167-1175页

作者： GAO Feng QI ChenKun ren AnYe ZHAOXianChao CAO Rui SUN Qiao WANG Qian HU yan HE Jun JIN ZhenLin LIU renQiang ZHANG Yong GUO WeiZhong HU ZhenYu TANG Ping NI Bo JING QianFeng WANG WeiJun GAO Peng State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China Institute of Aerospace System Engineering Shanghai Shanghai 201108 China School of Mechanical Engineering Yanshan University Qinhuangdao 066004 China

In the one-gravity environment on the ground, the simulation of the contact process of two flying objects in the zero-gravity environment of space has been a challenging issue since humans first explored space by flying objects. Hardware-in-the-loop （HIL） simulation is an important and effective method to test the usability, reliability, and safety of real docking mechanisms in space. There are four main issues for HIL simulation systems： Design of simulators capable of high frequency response, high motion precision, high velocity, and rapid acceleration; compensation for simulation distortion; design of a control model for the HIL simulation process; and experimental verification. Here, we propose a novel HIL simulator system with a 6-DOF 3-3 perpendicular parallel mechanism and a 3-DOF 3-PRS parallel mechanism; discover the principle of simulation distortion; present distortion compensation models for the force measurement system, dynamic response, and structural dynamics of the simulator; and provide a control model for the HIL simulation process. Two kinds of experiments were performed on the pas- sive-undamped elastic rod and the docking mechanisms to test their performances and to verify the effectiveness and usability of the HIL simulator. The HIL simulation system proposed in this paper is useful for developing space docking, berthing, refu- eling, repairing, upgrading, transporting, and rescuing technologies.

关键词： hardware-in-the-loop simulation hybrid simulation docking simulation contact dynamics parallel mechanisms simulation distortions distortions compensation

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基于代数算法的单元模态应变能灵敏度分析

振动与冲击 2010年第4期29卷 34-39页

作者：颜王吉任伟新中南大学土木建筑学院长沙410075

模态应变能在基于振动的结构损伤识别中得到了广泛的应用,其灵敏度分析成为了当前的一个重要问题。采用代数方法解析推导出了无阻尼线性系统单元模态应变能一阶和二阶灵敏度的解析表达式,该表达式简洁紧凑,便于编程,而且只需一阶模态信... 详细信息

模态应变能在基于振动的结构损伤识别中得到了广泛的应用,其灵敏度分析成为了当前的一个重要问题。采用代数方法解析推导出了无阻尼线性系统单元模态应变能一阶和二阶灵敏度的解析表达式,该表达式简洁紧凑,便于编程,而且只需一阶模态信息,不存在模态截断引起的误差问题。通过数值模拟算例,对得到的单元模态应变能一阶灵敏度进行了参数分析,并着重考查了损伤及其噪声的影响。结果表明,低阶单元模态应变能比高阶模态能更好地反映出结构损伤,而且抗噪能力更好。

关键词：特征值特征矢量刚度矩阵模态应变能结构动力学损伤识别

Effect of Unit Cell Shape on Switchable Infrared Metamaterial VO_(2)Absorbers/Emitters

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Research 2021年第1期2021卷 994-1001页

作者： Feifei ren Jinxin Gu Hang Wei Gaoping Xu Jiupeng Zhao Shuliang Dou Yao Li 1 Center for Composite Materials and Structure Harbin Institute of TechnologyHarbin 150001China School of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150001China

Metamaterial absorber/emitter is an important aspect of infrared radiation *** this paper,we proposed four simple switchable infrared metamaterial absorbers/emitters with Ag/VO_(2)disks on the Ag plane employing triangle,square,hexagon,and circle unit *** spectral absorption peaks whose intensities are above 0.99 occur at~4μm after structure optimization when VO_(2)is in insulating state and disappear when VO_(2)becomes metallic *** simulated electromagnetic field reveals that the spectral absorption peaks are attributed to the excitation of magnetic polariton within the insulating VO_(2)spacer layer,whose values exceed 1.59 orders of magnitude higher than the incident magnetic *** resonant wavelength would be excited in square arrays because its configuration is a better carrier of charges at the same *** absorption stability,the absorbers/emitters with square and circular structures do not have any change with the polarization angles changing from 0°to 90°,due to the high rotational symmetric *** four absorbers/emitters reveal similar shifts and attenuations under different incident *** believed that the switchable absorber/emitter demonstrates promising applications in the sensing technology and adaptive infrared system.

关键词： emitter polarization absorber