自锚式悬索桥边跨整体索夹的设计优化

南京长江隧道工程江心洲右汉大桥边跨索夹采用两道主缆连成一体的形式,索夹顶部设钢横梁,吊索上端与钢横梁连接,该结构形式稳定性不高,为提高稳定性,把钢横梁由顶部移到底部;同时,原钢横梁组焊件改为整体铸钢件,并调质热处理,有效地提高了钢横梁的结构安全储备。     

深圳地铁一号线续建工程车辆司机室视野分析

文章介绍了深圳地铁一号线续建工程车辆司机室视野分析及其相关的司机座椅高度、位置确定方法,司机操纵台高度设计和前窗大小计算方法。     

HXD1C机车辅助变流器系统及特性分析

阐述了HXD1C机车辅助变流器系统及主电路逻辑控制过程,分析了主电路的等效阻抗、输入电感特性及中间直流环节特性,提出一种开关电压电流估算方法,并通过仿真对主电路电压电流波形进行分析,为进一步确保辅助变流器的正常稳定运行和辅助变流器的优化改善提供参考.     

HXD1系列机车司机室蒙皮下料及成型制造工艺

介绍了HXD1型机车司机室钢结构中主要蒙皮零件的结构设计特点,对下料和成型方法等关键工艺项点进行了详细的分析说明.     

上海别克轿车发动机点火控制系统

论述了上海别克轿车发动机点火控制系统各传感器和控制模块的功能、工作原理、故障码设置及故障诊断方法。     

堆载预压法处理道路软基的效果分析

本文通过广州市一条堆载预压 7年的道路工程资料研究 ,发现软基区填方路堤在 2 .5～ 3.0m间存在一临界高度。路堤低于临界高度时 ,路基沉降量随路堤增高增加缓慢 ;路堤高于临界高度时 ,路基沉降量随路堤增高迅速增加 ;但路堤高度一定时 ,软基沉降量随软土层厚度变大增加缓慢。堆载 7年后 ,在原埋深 3.0m以上的软土的物理力学性质改善 2 7%～ 6 9% ,3.0m以下软土的物理力学性质改善 1%～ 5%。     

车身结构件多步冲压工艺数值模拟

分析了左后悬挂架形成特点，采用两步拉延方式完成成形；然后确定首次拉延的四种方案，研究不同变形形式和变形量对后继拉延所造成的成形质量的影响；通过数值模拟结果中的FLD曲线、材料厚度分布图、最大主应变分布图和拉延成形变形裕度，研究车身结构件多步冲压工艺设计。     

模块化多电平换流器型直流输电系统启动控制

为抑制模块化多电平换流器型直流输电(MMC-HVDC)系统启动时产生的过电压和过电流,有必要对该系统的启动控制策略进行设计。文章基于MMC-HVDC拓扑结构,研究了连接有源或无源网络MMC子模块电容充电方法以及限流电阻的配置方案,并由此分别提出了双端有源和向无源网络供电的MMC-HVDC系统的启动控制策略,仿真结果验证了所设计的启动控制策略的正确性。     

6K型电力机车牵引拉杆座延寿方案

分析6K型电力机车牵引拉杆座裂纹产生的原因,利用有限元软件ANSYS对6K型电力机车牵引拉杆座进行有限元分析,评估疲劳强度,并进行了实际动应力测试,结合牵引拉杆座的不同受力和结构特点分别优化出相应的延寿方案,确保6K型电力机车再延长寿命10年.     

Environmental assessment in the Prc: Third phase of the Qinhuangdao coal port

Abstract

The use of environmental impact assessment (EIA) is relatively recent in the People's Republic of China (PRC). China is committed to a reversal of the environmental degradation resulting from its industrialization and the central government has initiated a requirement for environmental planning and assessment for large development projects. Today large scale harbor developments are subject to the requirements of the National Environmental Protection Law (1979) and the Marine Environmental Law (1982). Because the third phase expansion of the coal port of Qinhuangdao would increase the ports’ capacity to handle coal by 30 to 50 million tons, an EIA was required.

Since 1981, the Environment and Policy Institute of the East‐West Center (EWC), Honolulu, has had a program of research focusing on the environmental impacts of coal transportation. On the basis of workshops in China that centered on the problems associated with planning coal transportation projects, the Ministry of Communications of the PRC invited the EWC to participate in the environmental assessment for the third phase coal port expansion at Qinhuangdao. A 10‐member team with specialities in environmental assessment and port environmental problems from five countries representing the EWC worked with a 25‐member team from four different agencies of the PRC Ministry of Communications.

This article describes the environmental regulations in the PRC that affect this harbor expansion, discusses the process by which the EWC assisted the PRC in the preparation of the environmental assessment and evaluates the assessment product against PRC regulations and U.S. standards. The most important contribution of the EWC was the provision of guidelines adapted from the EIA experience in several countries which will assist the PRC in the environmental evaluation of future pon expansion projects.