城市轨道交通钢轨伤损分析

随着上海市轨道交通运营年限的不断增加,钢轨伤损已经成为影响线路安全性的一个重要因素.根据上海轨道交通1号线的钢轨损伤情况,对引起钢轨伤损的原因和伤损的数量进行统计分析.结果发现:上行和下行线路的伤损种类与分布大致相同;引起钢轨伤损的三个主要原因分别是焊接、轮轨作用以及钢轨的材质;钢轨裂纹主要发生在曲线地段.针对性地提出了关于减轻钢轨伤损的对策措施.     

我是传奇

正保时捷919 Hybrid性能之强可以肆意叱诧耐力赛场,攻城掠地,好不风光。开着它是一种什么样的感觉,保时捷运动赛车部门给了evo杂志一个极其宝贵的机会保时捷把这台919 Hybrid LMP1当做70周年纪念庆典的一部分就已经佐证了这台勒芒系列赛车拥有超越历史的特质:技术上大胆进取;功能性上极为稳定;最重要的,它令人发指地快。Veni, Vidi, Vici,我来,我见,我征服,919在各种厮杀角力之后一次又一次站在了耐力赛领奖台的顶端,它的成绩之好恐     

关于修订国标中形位公差项目的探讨

文章分析了GB1182—1996中形位公差项目设置存在的问题,提出了简化形位公差项目的修改意见,并对修改意见进行了可行性论证。     

地铁车站BAS的结构设计

结合实际工程项目,对车站BAS结构设计中的控制器,网络及控制箱分布等问题作简要分析.认为控制器宜选择PLC的中高端产品,数量不宜过多;网络宜采用分层结构,利用工业级网络构建BAS控制层网络;系统的控制箱柜宜相对集中安装.     

A study of polygonal wheel wear through a field test programme

High magnitude impact loads caused by polygonal wear of the wheels have been associated with in-service failures of structural components of high-speed railways, although the mechanisms leading to wheels’ polygonalisation is not yet fully understood. In this study, a long-term field test programme is undertaken and the data are analysed to gain better understanding of the growth in polygonal wear, and its characteristics and correlation with the axle box acceleration. The field measurements on a high-speed railway involved monitoring of wheels profiles between successive re-profiling of the wheels so as to identify the rate of growth of wear in addition to the axle box acceleration. The data suggested rapid growth in wheel wear, which could be characterised by polygonal wear of nearly 18th and 19th harmonic order. It is further shown that the magnitude of axle box acceleration increased considerably with increasing wear magnitude of the wheel.     

基于灰色小波神经网络的船舶交通流预测研究

船舶交通流预测的准确性和可靠性已成为制约港口经济科学发展的瓶颈因素。文章综合利用小波变换的局部化性质与神经网络的自学习能力,并引入灰色模型以反映船舶交通流的发展趋势,使得小波神经网络在灰色模型预测结果的基础上结合船舶交通流的影响因素再预测,构成基于灰色小波神经网络的船舶交通流组合预测模型。实验结果表明,灰色小波神经网络的预测精度高于BP神经网络与小波神经网络,提高了整个预测系统的精度及其鲁棒性。     

利用Hopfield神经网络解决TSP问题

从Hopfield神经网络原理出发,结合TSP问题的要求,求得问题的最优解的次优解。并通过解决实际问题,说明了算法的有效性。     

对消式舰船有源隐身技术研究

有源对消隐身是现代隐身技术发展的一个重要方向,它能在传统隐身的基础上进一步降低受保护目标被雷达发现的概率。介绍了舰船有源对消隐身的基本原理,分析了对消波（场）的辐射特性,论述了雷达截面预估现状,探讨了雷达截面预估对舰船有源对消隐身的重要意义。     

战时战术级维修力量分配模型

针对将有限维修力量（服务台）分配给维修站（定点维修）和各需求点（伴随维修）的问题,提出了一个维修资源配置的优化决策模型,模型的目标是使整个战术区域内故障装备的不可用时间最小。     

H∞ Robust Fault-Tolerant Controller Design for an Autonomous Underwater Vehicle＇s Navigation Control System

In order to improve the security and reliability for autonomous underwater vehicle (AUV) navigation, an H_∞ robust fault-tolerant controller was designed after analyzing variations in state-feedback gain. Operating conditions and the design method were then analyzed so that the control problem could be expressed as a mathematical optimization problem. This permitted the use of linear matrix inequalities (LMI) to solve for the H_∞ controller for the system. When considering different actuator failures, these conditions were then also mathematically expressed, allowing the H_∞ robust controller to solve for these events and thus be fault-tolerant. Finally, simulation results showed that the H_∞ robust fault-tolerant controller could provide precise AUV navigation control with strong robustness.