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System dynamics in structural strength and vibration fatigue life assessment of the swing bar for high‐speed maglev train

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International Journal of Mechanical System Dynamics 2022年第2期2卷 178-189页

作者： feng Guo Feifei Hu Shengchuan Wu feng He Jianxin Liu xingwen Wu State Key Laboratory of Traction Power Southwest Jiaotong UniversitySichuanChengduChina School of Mechanical Engineering Southwest Jiaotong UniversitySichuanChengduChina

High‐speed maglev trains are subjected to severe dynamic loads,thus posing a failure *** is necessary to account for the vehicle dynamics to improve the structural strength and fatigue life assessment approach under harsh routes and super high‐speed *** the most critical load‐carrying part between the vehicle body and levitation frames,the swing bar was taken as an example to demonstrate the significance of vehicle dynamics to integrate classical structural strength and fatigue life with the service conditions.A multiphysics‐coupled dynamic model of an alpha improvement scheme for an electromagnetic suspension maglev train capable of 600 km/h was established to investigate the complex dynamic loads and fatigue *** this model,the structural strength and fatigue life of the wrought swing bars were *** show only a slight effect on the structural strength and fatigue life of swing bars by the super high‐speed *** nonaxial bending moments caused by the uncompensated relative displacement between the vehicle body and bolsters are identified as the decisive *** minimum safety factor of the structural strength for wrought swing bars is 1.33,while the minimum fatigue life is 34 *** match the design requirements but are not conservative ***,further verification and optimization are recommended to improve the design of swing bars.

关键词： vibration fatigue life dynamic strength levitation frame high‐speed maglev train time‐domain stepwise fatigue assessment(TSFA)

Convection effect on an arc plasma evolution process in a two parallel contact system

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Plasma Science and Technology 2020年第4期22卷 55-63页

作者： Jianning YIN Shungui LIU feng TANG Qishen LV xingwen LI State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'an 710049People’s Republic of China Shenzhen Power Supply Co.Ltd Shenzhen 518020People's Republic of China

A low voltage circuit breaker(LVCB)is an important piece of protection equipment which will switch off the fault current in a power *** moving contact of a low voltage circuit breaker with a higher rated current consists of two parallel ***,the convection effect on the air arc evolution process in a two parallel contact system is analyzed.A threedimensional(3 D)magneto–hydro–dynamic(MHD)model of arc simulation is *** this model,the anode consists of two parallel contacts and a bonding conductor.A nonlinear voltage–current density characteristic is employed to represent the near-anode and near-cathode *** current density,arc voltage and currents through every contact are *** influence of convection and conduction on the arc evolution process are quantitatively *** displacements of the arc roots are obtained and the asymmetry of the arc root motion is *** arc evolution process of a two parallel contact system is preliminarily revealed.

关键词： air arc circuit breaker MHD

Classification of Universal Applied Datasets Based on Convolutional Neural Networks

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Classification of Universal Applied Datasets Based on Convol...

Stability Analysis of Discrete-Time Almost Periodic Piecewise Linear Systems with Dwell Time Uncertainties

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作者： xingwen Zhao feng Ye Lijun Hang School of Automation Hang Zhou Dianzi University

This work focuses on the design of convolutional neural network to achieve precise classification of universal dataset in specific applications. The paper presented a high-resolution application-oriented image dataset with universal characteristics. The dataset includes a total of 20000 images of 12 categories, currently covering the most common categories of digital products, transportation, and animals. Aiming at the dataset, the methods of rotation, translation and flip, were adopted for data augmentation to enrich the diversity of dataset and to prevent the over-fitting problem. A total of eight-weight neural network was designed, including five convolutional neural networks and three full-connection layers. This paper uses the design of overlapping maximum pooling layer to better reflect the details of the information and to minimize the data loss of the pictures. The convolution kernel size of 3 * 3 was finally determined for feature extraction, which had been shown to be effective in alleviating the under-fitting problem in the early stage. It was proved that the Rectified Linear Units with a low initial learning rate of Stochastic Gradient Descent strategy would get better accuracy. And l2 regularization as well as dropout was used to optimize the model, which effectively prevented the over-fitting problem occurring in the latter part of the model training. The proposed optimal method and network configuration help to obtain an average accuracy of 94% on the dataset, and can precisely classify the transportation as well as digital products in specific applications, and also achieve the classification of the most common animal categories.

关键词： convolution neural network universal dataset classification and recognition

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Stability Analysis of Discrete-Time Almost Periodic Piecewis...

Infective viruses produced from full-length complementary DNA of swine vesicular disease viruses HK/70 strain

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作者： Fei feng xingwen Liu Jinnan Luo Center for Intelligent Complex Systems College of Electrical Engineering Southwest Minzu University

This paper addresses the issue of exponential stability of discrete-time almost periodic piecewise linear systems(APPLSs) with dwell time uncertainties under mode-dependent average dwell time(MDADT) switching signal. Considering dwell time uncertainties in discrete-time APPLSs, multiple piecewise convex homogeneous Lyapunov function(MPCHLF) is constructed. In the case where the switching instants within each period are unknown but lie within a certain range, a sufficient exponential stability condition for the discrete-time systems is proposed. Finally, a numerical example validates obtaining low conservatism using the proposed approach.

关键词： Almost periodic piecewise systems discrete-time swhitched systems dwell time uncertainties exponential stability

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Chinese Science Bulletin 2006年第17期51卷 2072-2078页

作者： ZHENG Haixue LIU Xiangtao SHANG Youiun WU Jinyan BAI xingwen JIN Ye SUN Shiqi GUO Huichen TIAN Hong feng Xia YIN Shuanghui GUO Jianhong CONG Guozheng LIU Zaixin CHANG Huiyun MA Junwu XIE Qingge Key Laboratory of Animal Virology of Ministry of Agriculture State Key Laboratory of Veterinary Etiological Biology Lanzhou Veterinary Research Institute Chinese Academy of Agricultural SciencesLanzhou 730046 China Graduate School Chinese Academy of Sciences Beijing 100081China

The full-length cDNA clone of swine vesicular disease virus HK/70 strain named pSVOK12 was constructed in order to study the antigenicity, replication, maturation and pathogenicity of swine vesicular disease virus. In vitro transcription RNA from pSVOK12 transfected IBRS-2 cells and the re- covered virus RNA were isolated and sequenced, then indirect hemagglutination test, indirect im- munofluorescence assays, eleectron microscope test, 50% tissue culture infecting dose (TCID50) assays and mouse virulence studies were performed to study the antigenicity and virulence of the recovered virus. The result showed that the infectious clones we ob- tained and the virus derived from pSVOK12 had the same biological properties as the parental strain HK/70. The full-length infectious cDNA clone, pSVOK12, will be very useful in studies of the anti- genicity, virulence, pathogenesis, maturation and replication of SVDV.

关键词：猪水泡病病毒 cDNA 传染性克隆 pSVOK12 反求遗传学

采用光纤传输激光的激光诱导击穿光谱系统参数

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高电压技术 2020年第9期46卷 3301-3310页

作者：吕启深邱岩唐峰吴坚李兴文深圳供电局有限公司深圳518020 西安交通大学电力设备电气绝缘国家重点实验室西安710049

实现元素含量的精准检测十分关键,目前对耐热钢材料元素成分的测量方法多为火花直读光谱法、X射线荧光法或人工取样后实验室分析,均不具备远程在线检测元素成分的能力。为此搭建了光纤式激光诱导击穿光谱(fiber-optic laser-induced bre... 详细信息

实现元素含量的精准检测十分关键,目前对耐热钢材料元素成分的测量方法多为火花直读光谱法、X射线荧光法或人工取样后实验室分析,均不具备远程在线检测元素成分的能力。为此搭建了光纤式激光诱导击穿光谱(fiber-optic laser-induced breakdown spectroscopy,FO-LIBS)系统,并基于LIBS光谱分别从连续背景辐射强度、谱线稳定程度和谱线强度对光纤系统包括探测延时、曝光时间和光纤终端到透镜距离的关键参数进行优化。探测延时主要用于衰减等离子体早期连续辐射,曝光时间则主要力求光谱信号稳定,光纤终端到透镜距离主要影响激光聚焦光斑大小,进而影响能量沉积过程,应确保光谱强度处于最高状态。在优化整个光纤系统的基础上,采用快速成像、激光纹影等诊断方法研究了光纤传输激光诱导钢材料等离子体的演化特性,获取光纤系统棒状等离子体膨胀速率(约0.23 km/s)及其激波的扩散轨迹。进一步采用内定标方法针对标准钢样品建立了痕量元素的定标曲线,其中痕量Cr元素的检测限(质量分数)可达160×10-6。研究表明光纤式激光诱导击穿光谱系统可有效识别钢材料的元素组分、定标元素含量,其现场应用有利于实现在役钢材料元素含量分布及其变化的远程在线诊断。

关键词：光纤式激光诱导击穿光谱激光诱导等离子体等离子体诊断元素分析辐射光谱

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四川省国有控股上市公司社会责任综合评价

财经科学 2010年第4期 72-77页

作者：黄娟冯建任兴文西南财经大学会计学院四川省国有资产监督管理委员会

国有控股上市公司作为特殊的公众公司,践行社会责任是其可持续发展的应有之义和必然诉求。本文从国有控股上市公司社会责任评价体系的构建出发,运用灰色关联分析法对2008年四川省国有控股上市公司社会责任履行情况进行了综合评价,旨在... 详细信息

国有控股上市公司作为特殊的公众公司,践行社会责任是其可持续发展的应有之义和必然诉求。本文从国有控股上市公司社会责任评价体系的构建出发,运用灰色关联分析法对2008年四川省国有控股上市公司社会责任履行情况进行了综合评价,旨在促进国有控股上市公司与资本市场的和谐稳定健康发展。

关键词：企业社会责任灰色关联分析国有控股上市公司

后稳定型全膝关节置换后动态关节松动治疗有利于早期功能恢复

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中国组织工程研究 2021年第12期25卷 1842-1846页

作者：林奕冯杰荣罗兴文南方医科大学顺德医院(佛山市顺德区第一人民医院) 广东省佛山市528308

背景:早期康复介入有利于全膝关节置换后关节功能的恢复,动态关节松动能缓解膝关节的疼痛,最大限度改善膝关节功能。目的:探讨动态关节松动对后稳定型全膝关节置换后早期功能障碍及关节功能的影响。方法:选择2017年5月至2020年4月在南... 详细信息

背景:早期康复介入有利于全膝关节置换后关节功能的恢复,动态关节松动能缓解膝关节的疼痛,最大限度改善膝关节功能。目的:探讨动态关节松动对后稳定型全膝关节置换后早期功能障碍及关节功能的影响。方法:选择2017年5月至2020年4月在南方医科大学顺德医院行固定平台后稳定型全膝关节置换治疗的患者70例,随机分为2组。对照组术后进行快速康复介入,治疗组在术后给予动态关节松动结合快速康复介入治疗。比较两组患者术后1 d、2周、4周的西安大略和麦克马斯特大学骨关节炎指数和美国特种外科医院膝关节功能评分。结果与结论:(1)术后2周和4周,两组患者各项指标与组内治疗后1 d比较均有显著改善,差异有显著性意义(P<0.05);除美国特种外科医院评分的肌力项目外,术后2周和4周之间两组各项指标差异均有显著性意义(P<0.05);(2)术后2周和4周,治疗组美国特种外科医院评分系统中疼痛、功能、活动度、稳定性、屈曲畸形和总分均明显高于对照组,西安大略和麦克马斯特大学骨关节炎指数和美国特种外科医院评分的减分项目评分明显低于对照组(P<0.05);(3)结果表明动态关节松动结合快速康复介入有助于全膝关节置换后的早期功能恢复。

关键词：关节全膝关节置换动态关节松动固定平台后稳定型快速康复肌力

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直流空气电弧作用下触头烧蚀特性

高电压技术 2020年第6期46卷 1970-1977页

作者：李兴文吕启深田甜吴艺红唐峰西安交通大学电力设备电气绝缘国家重点实验室西安710049 深圳供电局有限公司深圳518020

触头烧蚀会影响低压断路器的使用寿命和可靠性,研究触头烧蚀特性对于低压断路器的研制具有重要意义。为此建立了直流空气电弧作用下的触头烧蚀模型,考虑蒸发和喷溅两种烧蚀机制。针对触头熔池的传热和流动现象,建立了熔池的二维磁流体... 详细信息

触头烧蚀会影响低压断路器的使用寿命和可靠性,研究触头烧蚀特性对于低压断路器的研制具有重要意义。为此建立了直流空气电弧作用下的触头烧蚀模型,考虑蒸发和喷溅两种烧蚀机制。针对触头熔池的传热和流动现象,建立了熔池的二维磁流体动力学模型,并结合熔化凝固模型模拟触头熔化相变过程。在熔池模型的基础上,建立蒸发和喷溅烧蚀模型。基于Langmuir方程和气体动力学理论建立蒸发模型,综合考虑沸点以下蒸发过程和沸点以上蒸发过程,分析蒸发通量与熔池表面温度的关系。基于概率统计理论建立喷溅烧蚀模型,得到材料的喷溅烧蚀质量。此外,定量分析触头材料、电流、触头尺寸和触头形状4种因素对触头烧蚀特性的影响,以期得到降低触头烧蚀的方法。研究结果表明:电流低于20 A时以蒸发烧蚀为主,电流高于200 A时以喷溅烧蚀为主;在保证触头尺寸大于熔池尺寸的前提下,减小圆柱形触头的半径,可降低触头材料烧蚀,但触头尺寸对触头烧蚀的影响很微弱;同等条件下半球形触头烧蚀质量最大,其次是圆台形,圆柱形触头烧蚀质量最小。

关键词：直流空气电弧蒸发烧蚀喷溅烧蚀熔池低压断路器