SMA沥青混合料粗集料用量的变化对路用性能的影响规律研究

SMA沥青路面结构混合料中粗骨料含量高是其显著特征之一,如何有效控制粗骨料含量,保证其骨架嵌挤密实结构的力学性能,其用量变化对沥青路面路用性能的影响规律如何,本文通过试验进行研究。     

对快速公交系统引导郑州城市发展的认识

快速公交（BRT）作为一种可持续交通方式,体现着“公交优先”和“以人为本”的理念,BRT以其大容量、低耗能、快速、环保和乘坐舒适安全等特点成为解决城市交通问题的有效手段之一。本文以郑州市为例,鉴于常规公交存在的一些问题,分析了发展BRT系统的必要性,并对郑州BRT系统的构成和运营情况进行了介绍,预示着BRT系统在郑州得到成功实施;最后分析了BRT系统对郑州城市旅游业、房地产行业和商业的发展带来的积极影响。     

Development of a knowledge-based hybrid failure diagnosis system for urban transit

Urban transit is a complex system that contains both electrical and mechanical entities; therefore, it is necessary to construct a maintenance system for ensuring safety during high-speed driving. Expert systems are computer programs that use numerical or non-numerical domain-specific knowledge to solve problems. This research aims to develop an expert system that diagnoses the causes of failures quickly and displays measures to correct them. For the development of this expert system, the standardization of a failure code classification and the creation of a Bill of Materials (BOM) were first performed. Through the analysis of both failure history and maintenance manuals, a knowledge base has been constructed. Also, for retrieving the procedure of failure diagnosis and repair linking with the knowledge base, we have built a Rule-Based Reasoning (RRB) engine with a pattern matching technique and a Case-Based Reasoning (CBR) engine with a similar search method. Finally, this system has been developed as web based in order to maximize accessibility.     

ZPW-2000A闭环电码化工作原理及试验方法浅议

本文介绍了ZPW-2000A闭电码化在铁路运营中的重要作用，并分别对工作原理及现场施工中的试验环节进行了分析，提出闭环检查条件应用于进出站信号机控制电路的必要性。     

群锚作用的受力浅析

通过对群锚作用下的作用机理、荷载传递进行分析,使用剪切位移—传递函数法进行荷载传递位移计算。     

霍尔罗经

利用半导体霍尔器件作为传感器直接敏感地球磁场的磁感应强度，研制成固态罗经。本文对霍尔罗经的构成、钢铁船舶对其指向的影响及同纬度自差校正理论和方法，作了较全面的论述。     

电气化铁道谐波影响及其标准综述

通过对国际电工委员会制订的IEC61000系列标准总体构架和具体内容的描述,解读供电网络谐波影响及其指标要求的实质和内涵,并以此来对照国家标准和电气化铁道供电网络谐波的内在关联,找出相互之间存在的差异和问题,以期对相关国家标准、铁道行业标准的执行和制、修订提供有益的借鉴。     

铁路信号系统雷击试验中存在的问题探讨

对铁路信号系统上道信号设备雷电电磁脉冲抗扰度进行室内动态模拟试验,是保障信号设备应用可靠性的重要环节。按照现行铁道行业标准规定的试验方法和试验检测方法进行室内动态模拟试验,存在着对防护盲区和冲击损坏积累效应漏检的问题。通过分析试验结果,说明防护盲区、冲击损坏积累效应产生的原因和漏检的可能性,并提出相应防范措施。     

港口国监督检查选船如何避免产生“马太效应”

文中从概念、历史数据、数学模型角度分析了当前港口国监督检查中的目标因素评价体系，以及其存在阶段性正反馈所导致马太效应的原因，认为这种评价体系由于缺乏科学的动态正反馈限制以及连续性计算，而将不可避免地导致具有不良记录的船舶在一段时间内无法公正地获得与其他船舶一样的对待。笔者借此文介绍了各备忘录组织所采用的“黑名单-灰名单-白名单”船旗国分类方法，并从数学角度对其进行了分析，认为其能够较好地解决正反馈限制修正以及连续性计算问题，建议仿效其建立“黑名单-灰名单-白名单”船舶分类方法，通过登轮系数修正目标因素值作为选船的依据之一，从而给具有不良记录的船舶以彻底改善船况、重新获得信用的机会。     

Multicomponent decomposition of a time-varying acoustic Doppler signal generated by a passing railway vehicle using Complex Shifted Morlet Wavelets

Complex Shifted Morlet Wavelets (CSMW) present a number of advantages, since the concept of shifting the Morlet wavelet in the frequency domain allow the simultaneous optimal selection of both the wavelet center frequency and the wavelet bandwidth. According to the proposed method, a cluster of CSMW wavelets is used, covering appropriate ranges in the frequency domain. Then, instead of directly processing the instantaneous frequency of each CSMW, an invariance approach is used to indirectly recover the individual harmonic components of the signal. This invariance approach is based actually on the same rotational approach, using the same matrix properties, which consists the core of the well known ESPRIT algorithm. Moreover, the DESFRI (DEtection of Source Frequencies via Rotational Invariance) approach is introduced to support the proposed CSMW method to semi-automated selection of the center frequency of the applied Morlet window. This approach is based on the singular values that are extracted as an intermediate product of the proposed decomposition process. By the application of the method in a multi-component synthetic signal a way to select the critical parameters of the Morlet wavelet, is investigated. The method is further tested on a time-varying acoustic Doppler signal generated by a passing railway vehicle, indicating promising results for the estimation of the variable instantaneous frequency and the multi-component decomposition of it.