新型计算机系统对计算结构力学的影响

在过去的20年中,计算机已有了爆炸性的增长,在下一个10年中,由于新型计算机结构和智能计算机的出现预期要增长得更快.下述的计算机硬/软件技术的进展会对结构力学产生很大的影响.     

低空防空系统的发展

普通脉冲雷达由于存在地物杂波干扰不能探测到低空飞行的飞机,多普勒雷达由此应运而生.雷锡恩公司首次研制了连续波多普勒雷达,并将之应用于“麻雀”和“霍克”导弹中.以后人们又研制了脉冲多普勒雷达,它兼有脉冲雷达和连续波雷达的特性.介绍雷锡恩公司研制连续波雷达中的关键技术,叙述防空问题的特殊观点.详细论述低空防空武器制导系统的基本技术问题(主要有指令、噪声和尖叫声等)和解决这些问题的主要途径.最后介绍低空防空导弹技术和雷达技术的进展以及现状.     

费用-效果分析在空间运输决策支持系统中的应用

低成本空间运输对保证正常扩大利用空间以及维持所需的地面/空间基地后勤支援是非常重要的.介绍了如何建立空间运输决策支持系统.重点介绍如何在该系统中采用费用-效果分析技术和分析程序.其目的是要提供一种计算机化的决策支持系统,使用户能按费用、进度和技术参数等来组成和评审空间运输系统结构.这种系统和用户有很强的交互作用性,能允许用户针对相同的和在变化中的判据来评审/比较多种空间运输系统方案.     

MX第一级

1980年在 Montery 召开的 JANNAF 会议上,介绍了 MX 第一级原始方案论证及制订的研制方案。这篇新资料评论了最初的两次静态试验所取得的结果。     

美国用“阿里安3”发射卫星

美国卫星商用系统公司签订了一项计划在1986年10月用“阿里安3”发射SBS-5通信卫星的合同。该公司是预定要用欧洲运载器运送载荷的第二家美国公司。另一家公司则是GTE Spacenet公司。它在1984年5月22日在阿里安的第九次飞行试验中用“阿里安1”从法属圭亚那的库鲁成功地发射了Spacenet F1宇宙飞船,这是该公司计划发射的五个Spacenet/Gstar通信宇宙飞船中的第一个。预计在84年10月底发射Space-     

基于前后相关阵的CDMA信号DOA估计及DSP实现

本文针对CDMA系统,提出使用DSP器件TMS320C6701实现对CDMA信号的波达方向估计.该算法基于对解扩前后相关阵相减,去除了干扰相关阵,然后使用传统MUSIC或ESPRIT算法进行DOA估计,克服了要求接收信号数小于阵元数的局限,能有效估计波达方向相差很小的多径信号的参数.     

指数分布阶段可靠性增长模型的Bayes融合

对满足顺序约束条件的指数分布阶段可靠性增长模型，本文利用共轭型先验分布与由工程专家经验给出的延缓纠正有效性系数，给出了Bayes融合方法，讨论了Baves融合结果的工程物理意义，最后用数值例说明了这些方法。在某型导弹的发动机的可靠性评估中应用了该方法，验证了方法的有效性。     

端羧基聚丁二烯推进剂的老化特性(第一部分:老化与交联特性)

本文研究了固化剂和防老剂对 CTPB 推进剂加速老化的影响。如果使用的固化剂在羧基当量以上,那么推进剂中过量的固化剂就起着填料的键合剂的作用,但其反应速度远远慢于粘合剂的固化速度。苯二胺类化合物(CTPB 粘合剂的稳定剂)不仅降低交联速度,而且也降低交联密度。推进剂中的少量水分,按一级反应使填料与粘合剂间的交联断裂,进而使聚合物解聚。CTPB 推进剂的交联密度约为1×10~(-3)克分子/(厘米)~3,比粘合剂的交联密度高一个数量级。     

Skylab experiment M-092: results of the first manned mission

Blood pressure at 30-sec intervals, heart rate, and percentage increase in leg volume continuously were recorded during a 25-min protocol in the M092 Inflight Lower Body Negative Pressure (LBNP) experiment carried out in the first manned Skylab mission. These data were collected during six tests on each crewman over a 5-month preflight period. The protocol consisted of a 5-min resting control period, 1 min at -8, 1 min at -16, 3 min at -30, 5 min at -40, and 5 min at -50 mm Hg LBNP. A 5-min recovery period followed. Inflight tests were performed at approximately 3-day intervals through the 28-day mission. Individual variations in cardiovascular responses to LBNP during the preflight period continued to be demonstrated in the inflight tests. Measurements of the calf indicated that a large volume of fluid was shifted out of the legs early in the flight and that a slower decrease in leg volume, presumably due to loss of muscle tissue, continued throughout the flight. Resting heart rates tended to be low early in the flight and to increase slightly as the flight progressed. Resting blood pressure varied but usually was characterized by slightly elevated systolic blood pressure, lower diastolic pressure, and higher pulse pressures than during preflight examinations. During LBNP inflight a much greater increase in leg volume occurred than in preflight tests. Large increases occurred even at the smallest levels of negative pressure, suggesting that the veins of the legs were relatively empty at the beginning of the LBNP. The greater volume of blood pooled in the legs was associated with greater increases of heart rate and diastolic pressure and larger falls of systolic and pulse pressure than seen in preflight tests. The LBNP protocol represented a greater stress inflight, and on three occasions it was necessary to stop the test early because of impending syncopal reactions. LBNP responses inflight appeared to predict the degree of postflight orthostatic intolerance. Postflight responses to LBNP during the first 48 hours were characterized by marked elevations of heart rate and instability of blood pressure. In addition, systolic and diastolic pressures were typically elevated considerably both at rest and also during stress. The time required for cardiovascular responses to return to preflight levels was much slower than in the case of Apollo crewmen.     

气象卫星云图的几何校正

气象卫星云图的几何失真较大,为了进行精确的几何校正,本文提出了经纬线网格校正方法。该方法分两步:第一步是根据气象卫星轨道参数对云图在大尺度范围内进行几何校正,即在云图上加上经纬线网格;第二步是在感兴趣的局部区域内根据经纬线网格进行精确的几何校正。实验证明,这种几何校正方法可以获得较高的精度。