铁路卫星通信网的系统功能设计

本文主要从系统设计的角度阐述对铁路卫星通信网的系统功能及其实现方式的考虑。     

通信网技术的发展及其市场预测

本文详细地评述了发展通信网所涉及的一些关键技术以及国外通信网的现状和发展趋热;并简要地介绍了我国通信网的发展情况;最后,对通信网市场进行了预测。     

Individual differences in sensitivity to nicotine: implications for genetic research on nicotine dependence

Recent evidence suggests that cigarette smoking has a heritability index around 53%. While related research on underlying mechanisms also supports the idea that genetic factors contribute to nicotine dependence--as well as to cofactors such as substance use and mood disorders--the nature of the behavioral traits and biological capacity for reinforcement that constitutes vulnerability to nicotine dependence is not well understood. The present review explores the problem of why some people become highly nicotine dependent, others develop a pattern of occasional use, and still others avoid the drug entirely despite extensive exposure and widespread experimentation with tobacco in the population. Recent research--both infrahuman and human--suggests that vulnerability to nicotine dependence is related to high initial sensitivity to nicotine and that the development of tolerance is more rapid and self-administration more extensive in such individuals. Relevant findings from neuroscience and biobehavioral research are reviewed in order to identify variables and methodologies that might improve the reliability and validity of behavioral and molecular genetic studies on cigarette smoking. The integration of research in these areas may lead to new insights in the understanding of nicotine dependence as well as to improved techniques for prevention and treatment.     

N—80油井套管的生产工艺及发展

介绍了N-80油井套管目前的生产状况,采用的钢种及有关生产工艺,以及今后的发展方向.     

卫星通信高速数据传输纠错技术新进展

本文扼要介绍最近卫星通信高速数据传输中采用纠错编译码技术的新进展,说明120Mb/s TDMA/DSI系统中BCH(128,112)码,45Mb/s IDR R3/4 Viterbi译码,以及70Mb/s卷积码与Reed-Soloman码级联等三种典型纠错的生成多项式,并行编译码技术及性能。它们对于卫星通信传输高速数字图像信号是非常有用的。     

GSM风靡全球

GSM是欧洲开发的数字蜂窝移动电话标准。现已扩展到欧洲以外的亚洲、非洲、南美、中东以及澳大利亚等地区。有关专家预测,到2000年,欧洲的GSM移动电话用户将达到190O万甚至可达2300万。其发展前景甚为乐观。本文主要介绍当前GSM在世界各地的发展,并以表格的形式展示各地区的经营现状。     

纤维光学技术及其军事应用(待续)

本文介绍了纤维光学技术的研究进展及其在各类军事装备和军事环境中的应用。本文分四部分:1.纤维光学技术的研究进展;2.纤维光学技术在陆军各领域的应用;3.舰船上的光纤通信和水下光纤通信;4.空军和机载光纤通信及光纤雷达。