一种基于DBF的双基地雷达系统的性能分析与实验研究

讨论了一种基于数字波束形成的脉冲追赶式双基地雷达系统的构成和基本工作原理．对该双基地雷达的性能进行了理论分析，并通过实验结果进行了验证。     

真空行业现状及未来国内市场

简单扼要的概述了真空行业的发展历史，以较详细的统计数据阐述了2002年行业经济运行情况，并通过对相关行业“十五”发展规划的研究，对今后5～10年真空设备的市场进行了分析预测。     

我国WCDMA系统产业化现状及挑战

我国移动通信制造业在2G上晚了十年，未能取得相应的市场份额。但在3G领域，已经逐渐同步业界先进水平。如何改变现有市场格局，我国移动通信业面临全新的机会和重大的挑战，本就我国WCDMA系统产业化现状做了简要论述。     

两个基于身份的数字签名方案的安全性改进

分析了文献[1]提出的两个基于用户身份的数字签名方案，发现其一般签名方案存在安全性缺陷，在此基础上建立了多重签名方案，但此方案也是不安全的。本文给出了改进的签名和多重签名方案。     

快速搜寻卫星数字压缩信号

在没有专业仪器，没有明确参照物的条件下，如何快速定位接收天线，搜索到卫星信号，是电视工程技术人员经常遇到的问题，本文就此问题提出了一个新的解决办法，即利用已知卫星的位置来定位其它卫星的位置。     

数字电视及其标准

电视技术的数字化是电视领域发展的必然趋势，它给电视技术带来了质的飞跃。在对比分析了电视模拟技术与电视数字技术的区别的基础上，对数字电视的相关技术及其标准进行了介绍，并提出了作者的看法与见解。     

准连续波体制雷达最大熵方法的算法选择

准连续体制作为一种新型雷达体制以其固有的优越性给雷达界带来了巨大的冲击。其数字信号处理系统的开发是进一步完善该体制雷达的关键。本文针对数字信号处理系统中最大熵谱外推电路的算法选择进行了研究。     

数字电视技术的内涵及发展趋势

以有线电视为重点介绍了电视信号的数字化概念、优点及数字电视发展的趋势     

Failure analysis of three reconditioned rail car couplers

Three reconditioned rail car couplers, arbitrarily identified as couplers, failed during service due to cracking of the front face. The three couplers were reportedly upgraded by quenching and tempering to enhance strength and toughness. The objective of this investigation was to determine the mode of crack propagation and the root cause of the observed failures. Verl E. (Bud) Kahle, P.E., was a professional failure analyst for more than forty years. After receiving his Bachelor of Science degree in physical metallurgy from Washington State University 1957, Bud was employed by the General Electric Company at a facility in Hanford, Washington. He later was employed by the Aerojet General Corporation and eventually was head of the Southern Pacific Materials Science Laboratory in Sacramento. After retirement from Southern Pacific he owned and operated his own firm, Kahle Metallurgical Consulting Services, for fifteen years. He came to be known as “the man with the answers” to clients in a variety of industries. Bud was a Life Member of ASM International. Many of Bud’s clients remarked on the high quality of his failure analysis case histories and encouraged him to have them published. After Bud passed away in 1999, his wife, Suzanne, approached ASM International to see if the society would be interested in publishing any of his work. Mrs. Kahle was able to supply a large number of reports, which Bud had carefully archived over the years. Journal of Failure Analysis and Prevention Associate Editor Michael Stevenson read through the collected case histories, selected the ones to be included in this issue, and edited them for journal publication. ASM International wishes to thank Mrs. Kahle for providing these case histories for publication.