捷达王配气机构维修

本文概述了捷达王用EA113型发动机配气机构的构造，详述了其拆卸和维修方法。     

高速列车一系横向半主动悬挂控制研究

传统的高速列车半主动控制的控制对象是列车车体振动,往往没有考虑列车轮对的振动。轮对振动影响列车脱轨系数和轮对磨耗,关系到列车安全性和经济性。为了改善列车轮轨动力学性能,对一系横向减振器进行建模与仿真研究,通过设定不同的一系横向阻尼值,分析一系横向减振器对列车动力学性能的影响规律,并将天棚阻尼控制算法应用在一系横向半主动控制上,与被动悬挂情况进行对比。仿真结果表明,在350km/h速度级下,采用一系横向半主动控制比无一系横向减振器,列车的平稳性指标、脱轨系数和轮轨磨耗均得到改善,整体动力学性能得到提高。     

The initiation of rotational motion of a lying object caused by wind gusts

In this paper, the initiation of motion of an object lying on a horizontal floor due to the aerodynamic force produced by a time-dependent wind is considered. It is assumed in this paper that when the aerodynamic force is large enough, the body starts to rotate around the most rearward supporting contact point, or pivoting point. This motion is analyzed by studying the dynamics of the rotation of the body around a pivoting point fixed to the floor, and placed in a gravity field under time-dependent aerodynamic loads produced by a non-steady incoming flow. This rotation initiation phase, which is relevant in the case of a time-varying gusty flow, is an intermediate phase between the two stages generally considered, namely, the initial static equilibrium without motion, and the final flight. In this intermediate phase, which is studied here, the rotational dynamics of the body should be taken into account and the gust characteristics as well, in order to determine whether once initiated the motion it leads to either a frustrated motion or to a successful one. A non-linear mathematical model has been developed, and a linear approximation is deduced, which allows us to obtain the condition for a successful flight. This condition shows two limits, valid for either long or short duration gusts, respectively. Some experiments have been performed in a gust wind tunnel, and results show a satisfactory agreement. To take into account the intrinsic random character of the phenomena in practical situations, expressions for the probability of exceeding the condition for successful flight under short duration gusts are obtained, assuming common probability density functions for the random parameters involved.     

基于混杂系统理论的CTCS-3级列控系统建模与仿真

列车运行控制系统(列控系统)显著表现出离散和连续同时存在的混杂特征。建立合适的模型无论对列控系统的前期设计还是后期分析都具有重要意义。针对列控系统的混合性,提出用混合自动机对列控系统进行建模,在Matlab环境下用Simulink和Stateflow对建立的自动机模型进行仿真分析,并以两车追踪场景为例对整个过程进行了介绍。仿真结果表明了该方法的有效性和可行性。     

Attenuation and distortion of compression waves propagating in very long tube

A lot of phenomena related to propagating various waves are seen when the high-speed train goes through the tunnel, the gas pipeline is broken due to an accident or the air brake of the wagon operates. For instance, a compression wave generated ahead of a high-speed train entering a tunnel propagates to the tunnel exit and spouts as a micro pressure wave, which causes an exploding sound. In order to estimate the magnitude correctly, the mechanism of the attenuation and distortion of a compression wave propagating along a very long tunnel must be understood and the experimental information on these phenomena is required. An experimental investigation is carried out to clarify the attenuation and distortion of the propagating compression wave in a very long tube. Experimental results show that the strength of a compression wave decreases with distance. The attenuation and distortion of compression waves are affected by the initial waveform of the compression wave and by the unsteady boundary layer induced by the propagating wave. The shape of a compression wave becomes different with the propagating distance; that is, a shock wave appears just head of a wavefront and an overshoot on pressure distribution is observed behind a shock wave due to the transition of the unsteady boundary layer.     

预测控制方法在列车速度控制中的应用

随着我国铁路建设的高速发展，列车运行速度不断提高，行车密度不断加大，原有的列车速度控制方法难以满足安全行车要求。本文研究了列车速度的预测控制方法。设计了列车预测控制策略，对列车运行速度进行实时预测及优化。针对列车速度的预测控制策略设计了系统仿真程序并进行了系统仿真，结果表明，采用预测控制可以根据以后的输入对列车速度和控制策略进行有计划的调整，提高了列车速度的控制效果和控制效率，利用在线估计预测模型，采用在线滚动优化和反馈校正策略，减少了由于模型不准确带来的误差。     

顶置凸轮轴式配气机构设计的若干问题

详细介绍了一种目前使用较多助传动较为特殊的顶置凸轮轴式配气机构的运动学计算方法。同时认为在高速发动机上，以气门升程为１ｍｍ时的曲轴转角来衡量配气相位和丰满系数较为合理；高速配气机机构设计中一个不可忽视的薄弱环节是气门间隙调整螺钉头部的挤压疲劳。     

上海地铁列车运行图自动编制系统

介绍了一个基于数据库和矢量图形的列车运行图自动生成系统的设计和实现。系统实现了数据的输入、修改，并根据数据的更新自动生成地铁列车运行图。     

新世纪档案工作发展思路

面对新世纪的机遇和挑战,要坚持档案为经济建设和社会发展服务的方针,解放思想,转变服务观念,改变服务方式,不断提高档案管理工作水平。     

一种BEPT仿真系统的设计与实现

BEPT是当前现场测试和分析列控中心(TCC)生成的应答器报文的硬件工具.受经济、人力等条件的制约,列控中心的现场测试具有诸多的局限性.开发列控中心测试平台的任务之一就是要实现对BEPT的功能仿真.利用面向对象程序设计方法实现了一种BEPT仿真系统模型,它不仅实现了与TCC之间基于FSFB/2安全通信协议的实时数据交互,还实现了应答器报文的解码及解码明文分析.实验表明,该系统能够仿真BETP的主要功能,并已成功应用于列控中心测试平台中.