Reliable container line supply chains

Container line supply chains, based on a near-frictionless international transport belief, have contributed to economic prosperity and also rendered themselves uniquely vulnerable to various risks. 9/11 terrorists attacks, the lock-out of American West Ports and the global breakout of SARS disease have gradually shown that a) the safety and reliability in the chains are facing an unprecedented challenge and b) traditional engineeringbased risk assessment methods are inadequate to deal with the threats from variational environments, especially in the era of terrorism rampancy. The purpose of this paper is, therefore, to develop a conceptual risk assessment model for container line supply chains based on a modified Formal Safety Assessment (FSA) methodology that takes risks from vulnerability rather than only hazards into account. It gives particular emphasis on the analysis of the threats with a high level of uncertainty from both safety and economic viewpoints. The advantages of the vulnerability-based risk analysis approach to the hazard-based one are clarified and both engineering-based and managerial risk assessments are also discussed.     

短波收信天线交换系统的初步设计

根据短波通信业务对收信天线交换的发展需求，简要介绍了短波收信天线交换系统的功能与结构，并对系统的功能模块进行了初步设计。     

短台阶开挖法在西安地铁地裂缝段施工的应用

通过对西安地铁2号线F5地裂缝段施工方案的可行性、施工措施、质量保证措施等的分析,经过方案比选,参考试验段施工情况和监控量测数据反馈的信息,将短台阶施工法成功应用于地裂缝段开挖.短台阶施工法能够降低施工难度,加快施工进度,节省施工成本,提高施工安全性及工作效率,是一种行之有效的开挖方法.     

城市轨道交通运营成本分析与控制

城市轨道交通可以有效缓解路面公共交通拥堵,并带动当地经济发展.但其运营成本高昂,如不通过有效手段进行控制,会给当地政府财政带来巨大压力.通过分析上海城市轨道交通的历史运营成本以及各项统计数据,针对各主要成本科目和专业进行剖析,提出有效控制城市轨道交通运营成本的措施和建议:车辆专业提高国家化率;信号专业——统一制式;客运专业——提高管理水平;申请创业优惠电价;准确预测客流量,管控票卡制作等.     

轨道车辆用橡胶弹性元件靠性试验台

为解决我国轨道车辆用橡胶弹性元件组合加载试验关键技术难题,提出了一种“搭积木”设计理念,设计了一台12通道组合加载试验台,重点介绍了试验台的设计原理与结构组成,并对典型产品进行了组合加载试验.实践证明该试验台各项设计参数完全满足试验要求,为我国轨道车辆用橡胶弹性元件的安全和可靠性研究提供了科研平台.     

基于ANSYS的深基坑承压水降压对周边环境影响分析

随着城市地下空间开发朝着深层发展,深基坑工程成为城市建设中的重要课题。当基坑达到一定深度后,不可避免地遇到承压水层的突涌问题。其中悬挂式止水帷幕的基坑,对承压水层的处理通常要求按需降压,既要保证基坑抗突涌稳定,同时也要尽可能保证对坑外承压水层产生较小的影响,特别是对于周边环境复杂、保护等级较高的基坑。利用ANSYS 10.0通用有限元软件中的热分析模块模拟基坑工程中承压水降压的过程,再通过结构模块继承承压水层水头降深结果,将其转换为土层的初始应变,最后经过结构模块的计算分析,得出准确的土体位移结果。为深基坑工程承压水降压设计以及对周边环境影响分析提供了一种新方法。     

大水位变幅下省水船闸水位分级研究*

省水船闸通过把总水头进行分级,减小每级工作水头,除节省船闸用水量外,还有利于解决高水头船闸的水力学问题,对我国西部山区河流船闸建设具有很好的适应性。在分析省水船闸运行原理的基础上,研究了理论省水率的计算方法及其随省水池级数、面积的变化规律,总结分析了影响省水船闸水位分级的主要因素。以广西右江百色水利枢纽通航船闸为依托工程,针对船闸上游水位变幅大、设计水头高、工程布置条件及运行方式复杂等特点,计算省水运行时剩余水头的变化规律。从运行水位、省水池级数和面积等方面,提出了省水池布置参数及大水位变幅下的省水船闸水位分级方式,进一步模拟计算不同运行方式下的船闸输水水力指标,论证了水位分级的科学性与合理性。     

Micro-Grinding Performance of Hard-Brittle Chip Materials in Precision Micro-Grinding Microgroove

The micro-structure on hard-brittle chip materials (HBCMs) surface can produce predominant functions and features. The micro-grinding with diamond wheel micro-tip is an efficient method to machine microstructure on HBCMs. However, different HBCMs and crystal orientation may have a significant influence on the micro-grinding performance. In this paper, the micro-grinding performance along different crystal orientation of HBCMs is investigated. First, a dressed 600^# diamond grinding wheel is used to micro-grind micro-structure on HBCMs. Then, the experiment of micro-grinding force test is completed. Finally, the quality of microgroove, the grinding ratio and the micro-grinding force are investigated and they are related to the crystal orientation of HBCMs. It is shown that the stronger resistance to the micro-crack propagation has the best quality of microgroove and the smallest grinding ratio. Moreover, the hardest single-crystal SiC has the best machinability and the micro-grinding force is 38.9%, 10.8% and 46.8% less than the one of sapphire, single-crystal Si and quartz glass, respectively. The direction to micro-grind easily is the crystal orientation 〈10\(\overline 1 \)0〉 for single-crystal SiC and sapphire. In addition, the micro-grinding force increases with the increase of the micro-grinding depth and feed rate and decreases with the increase of the grinding wheel speed.     

苏州轨道交通2号线轨道减振措施性能测试分析

在苏州轨道交通2号线隧道内采用III型轨道减振器扣件、中量级钢弹簧浮置板道床以及重型钢弹簧浮置板道床等3种减振措施的代表断面上,采用落锤法测量钢轨、轨枕、道床及隧道侧壁测点的振动时域信号,计算得到各断面上测点的传递函数,并评价分析了这3种减振措施的性能。选取对列车振动较敏感的轨道下穿居民小区路段进行地面振动测试,分析了地下列车运行对居民生活的振动影响。研究结果表明,苏州轨道交通所采取的大埋深及重型钢弹簧浮置板道床等减振措施是卓有成效的。     

基于地层损失的复合地层盾构隧道施工沉降研究

盾构隧道施工诱发地面沉降的影响因素较多,但主要因素可归结为地层损失引起的地层变形。基于现有地层损失的理论,对引起地层损失的注浆过程进行模拟,依此研究复合地层盾构隧道施工对地层沉降的影响。研究结果表明:隧道贯通时,土体最大沉降和隆起区域分别位于隧道拱顶和拱底;浆液的硬化会对地表和拱顶的沉降速率产生影响,当浆液弹性模量达到最终硬化的75%时,地表和拱顶的沉降速率达到最大值并开始逐步减小;地表和拱顶沉降随浆液的逐步硬化而趋于稳定,且拱顶沉降趋于稳定的速率更快。