西门子SIMATIC S5-115U可编程序控制器及其复位操作

本文介绍了在船舶广泛应用的西门子SIMATIC S5-115U可编程控制器的组成和系统原理。重点闸述了SIMATIC S5-115U可编程控制器的运行方式、重新启动和复位操作。最后以表格的方式介绍了常见故障的诊断方法。     

轿车产业的历史转折

从产业层面上讲，汽车市场由“井喷”阶段转入低速增长期，降价成为市场主旋律，竞争进入白热化状态，并从售前延伸到售后。汽车产品的对外贸易，出现了出口增长大大高于进口增长的良性态势。凡此种种现象，说明中国汽车产业的发展出现了一个新的转折。     

The Shanggongshan Tunnel Kunming Zhangjiuhe River Water Diversion and Water Supply Project

Kunming is the political and economical centre of the Yunnan Province in the south -west of China and one of the most beautiful historical and cultural cities in China. It is also one of the 14 cities in China that are severely short of water. In order to solve the supply problem and to allow for future development of the local society and economy, the "Kunming Zhangjiuhe River Water Diversion and Water Supply Project" was implemented. The total investment for the project is about USD 476 million.The objective is to establish a water supply system with a capacity of 0.6 million tons of water per day.Major parts of the project are:capacity by 0. 442 billion m3 and an annual water supply of 0. 245 billion m3;tunnels, but also some siphons);pacity of 0.4 million tons per day in the initial stage and 0.6 million tons per day once completed;length of 93.43 km;sons.Project completion is planned for the end of 2006.     

提高风动工具心轴的寿命

试验表明，通过选择适当的热处理工艺，使风动工具心轴的表面获得细小马氏体＋适量残余奥氏体＋小颗粒碳氮化合物的组织，从而使心轴的寿命达到设计要求。     

中高级轿车市场下半年预测

在轿车“如火如荼”的行情中,最亮的亮点是中高级轿车,今年上半年的中高级轿车销量已达19.4万辆,超过了2001年全年的销量,同比增长95％,高于行业平均增长率3个百分点。 中高级轿车在整个轿车市场中的比重在不断增长,如1月份达到轿车总销量的17.4％,6月份达到了22.4％,半年间增长了     

电喷发动机供油系统的故障与保养(二)

燃油泵的故障位置有:燃油泵内的安全阀漏油,或弹簧失效、单向阀不密封、滤网堵塞、油泵磨损以致导致油泵电机烧坏,无法供油。