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Prediction of three-dimensional elastic behavior of filament-wound composites based on the bridging model

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Defence Technology（防务技术） 2021年第2期17卷 609-616页

作者： Dong-mei Yin Bao-ming Li Hong-cheng Xiao National Key Laboratory of Transient Physics Nanjing University of Science&TechnologyNanjing210094China

This work provides a method to predict the three-dimensional equivalent elastic properties of the filament-wound composites based on the multi-scale homogenization *** the meso-scale,a representative volume element(RVE)is defined and the bridging model is adopted to establish a theoretical predictive model for its three-dimensional equivalent elastic *** results obtained through this method for the previous experimental model are compared with the ones gained respectively by experiments and classical laminate theory to verify the reliability of this *** addition,the effects of some winding parameters,such as winding angle,on the equivalent elastic behavior of the filament-wound composites are *** rules gained can provide a theoretical reference for the optimum design of filament-wound composites.

关键词： Lightweight design Filament-wound composites Bridging model Three-dimensional elastic properties

Friction and wear behavior and mechanism of low carbon microalloyed steel containing Nb

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China Foundry 2023年第3期20卷 263-270页

作者： mei-yi Yuan Jia-cheng Zhang Yi-tao Yang School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

Dry sliding friction and wear test of Nb containing low carbon microalloyed steel was carried out at room temperature,and the effect of Nb on the wear behavior of the steel,as welll as the mechanism was *** electron microscopy(SEM) and energy dispersive spectrometry(EDS) were employed to analyze the morphology and composition of the worn surface,and the structure evolution of the plastic deformation *** carbide content and type in the steel were analyzed by the electrolytic extraction device and X-ray diffraction(XRD).The experimental results demonstrate that the addition of 0.2% Nb can refine the grain and generate Nb C to improve the wear resistance of the *** enhancing the load and speed of wear experiment,the wear mechanism of the test steel with 0.2% Nb changes from slight oxidation wear to severe adhesion wear and oxidation *** with the load,the increase in the rotation speed exerts a greater influence on the wear of the test steel.

关键词： Nb content low carbon microalloyed steel friction and wear carbide

Analysis for the residual prestress of composite barrel for railgun with tension winding

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Defence Technology（防务技术） 2020年第4期16卷 893-899页

作者： Dong-mei Yin Bao-ming Li Hong-cheng Xiao National Key Laboratory of Transient Physics Nanjing University of Science&TechnologyNanjing210094China

Based on the elastic theory of cylindrical shells and the theory of composite laminates,a prediction model for the residual prestress of the simplified round composite barrel for railgun is *** the fibre pretension is considered in this model.A three dimensional numerical simulation for the residual prestress in the railgun barrel is carried out,by combining the temperature differential method with the element birth and death *** results obtained by the two methods are *** reveals that the distribution trends of residual prestress are *** the difference for residual prestress in the filament wound composite housing of barrel is relatively *** same finite element method is used to analysis the residual prestress in the non-simplified composite barrels for railgun,which are under different control modes of winding *** results mean that the residual prestress in barrel will increase while the taper coefficient for winding is ***,the sealing performance in bore is improved,but the strength of the filament wound composite housing *** addition,the axial and circumferential residual prestress in the filament wound composite housing with constant torque winding are close to the ones in iso-stress design for barrel.

关键词： Railgun Barrel Composite materials Filament winding Winding tension Residual prestress

Neuroprotective effects of genistein on SH-SY5Y cells overexpressing A53T mutant α-synuclein

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Neural Regeneration Research 2018年第8期13卷 1375-1383页

作者： Huan-cheng Wu qun-Liang Hu Shi-Jun Zhang Yan-Min Wang Zhan-Kui Jin Ling-Fu Lv Sai Zhang Zhen-Lin Liu Hong-Lian Wu Ou-mei cheng Graduate School Tianjin Medical University Tianjin China Tianjin Beichen Hospital Tianjin China Tianjin Key Laboratory of Neurotrauma Repair Institute of Traumatic Brain Injury and Neuroscience Center for Neurology and Neurosurgery of Affiliated Hospital Logistics University of Chinese People's Armed Police Force Tianjin China Department of Clinical Medicine Chongqing Medical University Chongqing China

Genistein, a potent antioxidant compound, protects dopaminergic neurons in a mouse model of Parkinson＇s disease. However, the mecha- nism underlying this action remains unknown. This study investigated human SH-SYSY cells overexpressing the A53T mutant of α-synuclein. Four groups of cells were assayed： a control group （without any treatment）, a genistein group （incubated with 20 μM genistein）, a rote- none group （treated with 50 μM rotenone）, and a rotenone ＋ genistein group （incubated with 20 μM genistein and then treated with 50μM rotenone）. A lactate dehydrogenase release test confirmed the protective effect of genistein, and genistein remarkably reversed mitochondrial oxidative injury caused by rotenone. Western blot assays showed that BCL-2 and Beclin ! levels were markedly higher in the genistein group than in the rotenone group. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling revealed that genistein inhibited rotenone-induced apoptosis in SH-SYSY cells. Compared with the control group, the expression of NFE2L2 and HMOX1 was significantly increased in the genistein ＋ rotenone group. However, after treatment with estrogen receptor and NFE2L2 channel blockers （ICI-182780 and ML385, respectively）, genistein could not elevate NFE2L2 and HMOX1 expression. ICI-182780 effectively prevented genistein-mediated phosphorylation of NFE2L2 and remarkably suppressed phosphorylation of AKT, a protein downstream of the estrogen receptor. These findings confirm that genistein has neuroprotective effects in a cell model of Parkinson＇s dis- ease. Genistein can reduce oxidative stress damage and cell apoptosis by activating estrogen receptors and NFE2L2 channels.

关键词： nerve regeneration genistein neuroprotection SH-SYSY cells Parkinson's disease rotenone estrogen receptor NFE2L2 A53T a-synuclein oxidative stress neurodegeneration neural regeneration

Dynamics of luffing motion of a hydraulically driven shell manipulator with revolute clearance joints

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Defence Technology（防务技术） 2022年第4期18卷 689-708页

作者： Chen Zhi-qun Qian Lin-fang Chen Guang-song Nie Shou-cheng Yin Qiang Yue Cai-cheng School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China Northwest Institute of Mechanical and Electrical Engineering Xianyang712099ShaanxiChina China North Industry Corporation Beijing100053China

In this study,a modeling method for investigating the dynamic characteristics of a hydraulically driven shell manipulator with revolute clearance joints is *** model accounts for the effect of the clearance,the flexibility of the rotating beam,and the coupled dynamic characteristics of the hydraulic cylinder.A modified contact force model was developed to simulate the physical properties of realistic revolute joints with small clearances,heavy loads,and variable contact stiffnesses and damping coefficients with variations of the *** the strong coupling relationship between the hydraulic cylinder and the flexible beam,a system equation of motion combining the state variables of the hydraulic cylinder and mechanical system was *** complex nonlinear friction force of the hydraulic cylinder motion was constructed using a modified Lu Gre model,and the parameters of the friction model were identified using intelligent identification ***,a test system for the shell manipulator was established to achieve experimental ***,the effects of the clearance size and the stiffness of the cylinder support on the dynamic response were investigated.

关键词： Parameter identification Shell manipulator Hydraulic cylinder Revolute clearance joint

Liver fibrosis evaluation by ARFI and APRI in chronic hepatitis C

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World Journal of Gastroenterology 2014年第28期20卷 9528-9533页

作者： Su-mei Li Guang-Xia Li Dong-mei Fu Yu Wang Li-qun Dang Department of Physical Diagnosis B Ultrasound Room Daqing Longnan Hospital Qiqihar Medical College Affiliated Fifth Hospital

AIM: To explore the value of liver fibrosis assessment by acoustic radiation force impulse (ARFI) and the AST/PLT ratio index (APRI) in chronic hepatitis C patients.

关键词： Liver fibrosis Chronic hepatitis C Acoustic radiation force impulse AST/PLT ratio index Sensitivity Specificity

Certain Subsets on Which Every Bounded Convex Function Is Continuous

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Acta Mathematica Sinica,English Series 2007年第6期23卷 1063-1066页

作者： Li Xin cheng Yan mei TENG School of Mathematical Sciences Xiamen University Xiamen 361005 P. R. China Department of Mathematics Beijing University of Aeronautics and Astronautics Beijing 100083 P. R. China

To guarantee every real-valued convex function bounded above on a set is continuous, how ＂thick＂ should the set be？ For a symmetric set A in a Banach space E,the answer of this paper is： Every real-valued convex function bounded above on A is continuous on E if and only if the following two conditions hold： i） spanA has finite co-dimentions and ii） coA has nonempty relative interior. This paper also shows that a subset A C E satisfying every real-valued convex function bounded above on A is continuous on E if （and only if） every real-valued linear functional bounded above on A is continuous on E, which is also equivalent to that every real-valued convex function bounded on A is continuous on E.

关键词： Convex function Boundedness Continuity Banach space

Non-isolated stacked bidirectional soft-switching DC-DC converter with PWM plus phase-shift control scheme

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Journal of Modern Power Systems and Clean Energy 2017年第4期5卷 631-641页

作者： Ye mei qun JIANG Heya YANG Wuhua LI Xiangning HE Shun LI College of Electrical Engineering Zhejiang UniversityHangzhou 310027China State Grid Zhejiang Electric Power Research Institute Hangzhou 310027China

In this paper, a non-isolated stacked bidirectional DC-DC converter with zero-voltage-switching(ZVS) is introduced for the high step-up/step-down conversion systems. The extremely narrow turn-on and/or turn-off duty cycle existing in the conventional bidirectional buck-boost converters can be extended due to the stacked module configuration for large voltage conversion ratio applications. Furthermore, the switch voltage stress is halved because of the series connection of half bridge modules. The PWM plus phase-shift control strategy is employed, where the duty cycle is adopted to regulate the voltages between the input and output sides and the phaseshift angle is applied to achieve the power flow *** decoupled control scheme can not only realize seamless bidirectional transition operation, but also achieve adaptive voltage balance for the power switches. In addition, ZVS soft-switching operation for all active switches is realized to minimize the switching losses. Finally, a prototype of 1 kW operating at 100 kHz is built and tested to demonstrate the effectiveness of the proposed converter and the control strategy.

关键词： Bidirectional DC-DC converter PWM plus phase-shift control(PPS) Zero voltage switching(ZVS) Large voltage conversion ratio Flexible power flow regulation

Ensuring consistency of Web services transaction

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The Journal of China Universities of Posts and Telecommunications 2009年第4期16卷 59-66页

作者： WANG Xiao-jun LI Yang-qun WU Xiao-mei MIN Li-juan Institute of Information and Network Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China Foreign Languages Office Nanjing Institute of Politics Nanjing 210003 China

Composite Web services provide promising prospects for conducting cross-organizational Web service transactions. Such transactions generally require longer processing time and manipulate financially critical data. To efficiently manage these Web services transactions, isolation is commonly relaxed, but inconsistency will be caused by concurrently executing isolation-relaxing transactions. This article proposes an extension to the WS-Business Activity Protocol, which ensures the consistent executions of isolation-relaxing Web service transactions, and which is based on transaction dependency graphs distributed over multiple nodes. Furthermore, this article presents several algorithms implementing the protocol, and introduces the implement of a prototype system.

关键词： Web services transaction model transaction management protocol consistency