Design considerations for a larger inmarsat standard ship earth station

A new standard of INMARSAT ship earth station for multi-channel operation could find particular application on large passenger ships and off-shore oil/gas platforms. This paper provides estimates of platform and ship motions and discusses general design requirements, notably of the antenna system. The discussion includes consideration of possible modulation and multiple access techniques. Single channel per carrier (SCPC) operation is advocated which permits easy integration with the present service to single channel INMARSAT Standard-A ship earth stations. Major parameter/relative cost trade-off curves needed in an overall ship earth station design optimization are presented.     

Google Earth的主要功能及其在广电行业的应用

本文简要介绍Google Earth的基本使用方法,具体说明其在广电行业的应用。     

无人运输机地面控制站显示界面的仿真系统

为实现地面控制站操作员对民用无人机的安全控制,提出了地面控制站集飞行仪表、地图综合界面显示设计方案. 采用GL Studio 和VC++ 6.0混合编程的方式,实现对飞行仪表显示界面的设计;使用VC++6.0 对Google Earth二次开发实现地面控制站地图显示功能. 将微软模拟飞行X作为飞行仪表和地图界面的数据驱动,通过UDP传输协议,实现仿真系统的综合测试. 测试结果表明,该系统设计可以为地面控制站操作员提供完整的态势信息,提高操作员的决策效率,为研究地面控制站显示界面工效问题提供新的方法.     

Calculation of ground resistance and step voltage for buried ground rod with insulation lead

Procedures for installing ground rods can be categorized into the driven ground rod methods and the buried ground rod methods. The leads of ground rods are also classified into two types—bare conductor leads and insulation leads. The analytical results herein elucidate a method for determining ground resistance, earth surface voltage, position and magnitude of the maximum step voltage for the buried ground rod with the insulation lead. The ground resistance, earth surface voltage and step voltage in the driven ground method exceed those of the buried ground rod with the insulation lead. Ground resistance, earth surface voltage and step voltage decrease as the depth of the buried ground rod increases. The position of the maximum step voltage varies with the buried depth of a ground rod with the insulation lead. The distance of the maximum step voltage from the ground rod increases with the depth of the buried ground rod. Results of this study provide a valuable reference for ground designs that protect humans and electrical equipment.     

发电厂直流系统故障在线监测仪的开发与应用

本文叙述了直流系统故障在线监测仪的工作原理及组成结构。在直流系统发生一点或多点接地时，该装置能迅速检查发生接地的直流支路编号及接地支路的极性，同时报警提示现场运行人员。本装置具有独特的预测功能，及早发现故障隐患，及时处理，以防患于未然。该监测仪已在佳木斯第二发电厂投入运行     

架空避雷线分流变电站入地电流的简易计算

高压送电线路的架空避雷线因防雷直接联接到变电站和线路杆塔的接地网,从而也将变电站内接地故障的入 地电流分流到站外,减少站内的入地电流。本文对分流作用提出一个简易的计算方法,可供变电站设计时作参考。     

Google Earth在东帝汶国家电网工程中的应用

当前越来越多的勘测设计单位承接境外电网工程,但又经常收集不到如地形图等基础资料,本文利用Google Earth提供的全球免费的地图影像平台,进行电网工程的优化设计,数据采集,生成断面图,排干定位,最后直观的显示出整个路径图,从而弥补了在国外勘测设计时基础数据的不足,同时也分析了采集Google Eanh三维影像数据进行初步排干定位的可行性,提高了勘测设计效率,对部分国内电网工程的勘测设计也有一定的借鉴作用。     

长输管道沿线高程提取技术研究

在Googel Earth卫星地图上选出长输管道线路,将线路经纬度坐标及高程借助一些工具软件迚行自动提取,并经过一番处理,在Excel中生成散点图,即里高程变化图。     

Thermal Explosions in the Early Evolution of the Earth

Exothermic regimes in the Earth's interior at an early stage of evolution are considered. Conditions are found that lead to selfaccelerating development of gravitational differentiation—separation of the heavier material forming the Earth's core from silicates in extended and heated local areas.     

一起高阻接地故障的事故分析

分析了一起220kV线路发生A相高阻接地故障,线路保护装置在先收到收讯输入变位信号的情况下,主程序处理数据速度变慢,导致高频保护拒动,并对此提出预防及整改措施。