辊弯成形仿真分析与参数优化(英文)

辊弯成形工艺是一种在常温下将平板金属材料通过连续转动的成形辊成形为所需截面的加工方法.本文通过有限元模型建立了一套避免重大产品质量缺陷的设计方法.通过对真实产品的仿真,在设计中考虑了两个辊弯成形主要缺陷,即边波和回弹.设计结果表明,该设计方法能够有效地控制这两大质量问题.     

Proton — an alternative launch system

Marconi Space Systems Ltd is a member of one of the two consortia bidding for INMARSAT's second-generation satellite system due to come into service from 1988. The Marconi consortium, which also includes Ford Aerospace and Communications Corp (USA) and Aérospace (France), had come close to opening negotiations in Moscow for using the Proton launcher to place the second-generation satellites into geostationary orbit before they were forced to abandon the idea. Dr Alastair C. Durney, a member of the editorial board of Space Policy, describes the pros and cons of Proton based on this experience. INMARSAT is expected to award contracts in early 1985.     

The USSR and space power plants

The American idea of a Solar Power Satellite was proposed for the first time in 1968 by Peter Glaser in a famous article in Science. This concept has since been the subject of many theoretical studies, and of some limited practical studies (mainly about microwave energy transmission) in the USA with funding from NASA and the Department of Energy (DOE). Some evaluations have been also conducted in Western Europe, particularly within the European Space Agency (ESA). But very little is generally known about the attitude towards SPS of the second main space power: the USSR. Soviet literature on SPS is much less abundant, but it does exist. Very interesting articles on the subject have been written by leading Soviet space experts. Some of these articles are analysed here, and the practical meanings of the ex[ressed opinions, generally very favourable, are investigated in view of the growing Soviet space capability.     

Environmental protection in space: a quantitative policy study

Survey data were collected in the USA from a national sample of chief executive officers. The first goal of the research was to identify national policies and strategies to control orbital debris, without imposing undue negative impacts on the US private and governmental space sectors. The second goal was to test a theoretical model, developed to predict the willingness of respondents to accept a national space environmental safety programme. National and International implications were drawn.     

抽屉原则与自由差集

运用抽屉原则的一般形式和整数集合中的自由差集能够解决一类组合理论中的一些实际问题。     

基于韦尔奇功率谱的雷达辐射源信号识别

应用韦尔奇功率谱原理提取信号识别特征参数,根据提取出的参数特点设计信号识别流程模型。从多种信号中检测识别线性调频信号、相位编码信号、频率编码信号。分析了特征的适用范围和信号环境。仿真分析该特征提取算法和识别方法的可行性。     

复合材料胶接工艺和胶接接头内应力分析

复合材料胶接连接工艺已被人们所肯定,在实践应用中反映出复合材料胶接接头中内应力是影响其胶接性能和耐久性的重要因素之一,文中简述了胶接工艺特点扣应具备的主要条件,胶接接头形成和胶接接头内应力分析等内容.