京九铁路广东段铁路专用线电磁防护

研究目的:上世纪京九铁路建设的同时,沿线一些企业利用该干线通道修建了运输专用线,近年京九铁路又进行了电气化改造。为确保安全,必须消除干线对专用线区域范围可能产生的电火花影响,因而要对专用线进行电磁防护。研究结论:在装卸作业区中,采用扁钢将鹤管及装卸钢栈桥的首末端及中间处,与其两旁的铁路钢轨之间相连接,安装均压装置作等电位跨接并接地;在专用线铁路中,在铁路钢轨上设置两组钢轨绝缘,并设接地装置,其接地电阻不大于10Ω。本文笔者结合京九铁路广东段电气化改造设计的实际经验与体会来阐述电磁防护措施,对类似的情况可起到一定参考作用。     

双壳油船底部破舱水下原油泄漏过程三维数值模拟

为研究双壳油船因搁浅或触礁导致底部破舱油品水下泄漏的过程,文中基于流体动力学理论,建立了双壳油船油舱三维数值模型,利用VOF模型表面跟踪方法对互不相容流体交界面液相流动问题进行了模拟,通过动态监测舱内油、水等运动特征对整个泄漏过程进行了阶段划分及特征分析,并将数值模拟结果与实验结果进行比较。比较结果表明：文中的三维数值模型能够比较准确地反映油品水下泄漏过程,可用于分析双层底内部流场特征。     

几种起动机电磁开关专利技术

介绍电装、法雷奥、博世及作者的带限流电阻的起动机电磁开关专利技术,对其工作原理、基本结构作了说明。     

Effects on Microstructure and Properties of Brass Treated by Laser Shock Processing

Laser shock processing （LSP） has been proposed as a new surface treatment for improving hardness, wear resistance and fatigue. In this paper, the effect of LSP on brass is investigated with experiment. Micro-hardness, roughness, microstructure, wear resistance and friction coefficient evolution are investigated for different parameters of LSP. The result shows that the roughness increases after LSP; no ablation is observed; the microstructure has no remarkable ehange; hardness and the wear resistance increase as the pulse density increases.     

Numerical Simulation of Projection Welding Processes for Door Hinge of Automobile Based on Coupled Fields Analysis

Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse of projection. As the joint type between the auto door hinge and the inner plate, projection welding may bring welding distortions and would affect the assembly quality of auto body. A comprehensive electric-thermal-mechanical numerical simulation was performed to quantitatively simulate the processes of projection welding by using a coupled finite element method. The mechanism of projection collapse and the formation process of nugget were discussed and good conclusions have been achieved comparing with the test results.     

一种新型宽带电阻膜吸波体设计

[目的]为了改善传统电磁吸波材料的吸波特性,基于阻抗匹配理论设计一种具有高吸收率的电阻膜吸波体.[方法]吸波体采用周期排布的电阻膜图案?介质基板?导体接地板结构,其电阻膜单元由耶路撒冷十字单元与外围的方环单元组合而成.[结果]仿真结果表明,所设计的吸波体在2.9～5.1 GHz的频率范围内对电磁波的吸收率超过90％,峰...     

分析桥梁冲孔桩施工过程中的溶洞处理措施

随着我国近几年城市化建设的不断加深,桥梁与道路等相关的基础设施建造无论从规模还是数量都极大的获得增加,冲孔桩施工技术是目前桥梁结构建筑中,应用比较广泛的工程技术之一.本文首先根据溶洞勘察处理方法作为基础出发点,同时结合桥梁溶洞处理措施,总结出目前我国桥梁建筑的主要技术手段.     

探讨白车身气密性能提升

本文主要通过对白车身泄露量大的问题进行分析,然后提升白车身气密性能。     

油气管道泄漏检测技术发展现状

简单说明了油气长输管道泄漏的原因和泄漏的危害,详细介绍了声发射技术法、GPS时间标签法、负压波法、压力点分析法、压力梯度法、状态估计法、神经网络法和统计检漏法等几种管道泄漏检测技术方法,最后指出了存在的问题和发展的趋势。