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211.
212.
J. S. Kaastra F. B. S. Paerels F. Durret S. Schindler P. Richter 《Space Science Reviews》2008,134(1-4):155-190
We discuss the different physical processes that are important to understand the thermal X-ray emission and absorption spectra
of the diffuse gas in clusters of galaxies and the warm-hot intergalactic medium. The ionisation balance, line and continuum
emission and absorption properties are reviewed and several practical examples are given that illustrate the most important
diagnostic features in the X-ray spectra. 相似文献
213.
雷达对抗仿真通用系统架构研究 总被引:1,自引:0,他引:1
分析了在雷达对抗仿真系统研制过程中,建立通用的系统架构带来的好处,并从仿真系统体系结构和功能设计两个方面,提出了实现通用系统架构的基本技术思路和方法。 相似文献
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215.
Low earth orbit has become increasingly congested as the satellite population has grown over the past few decades, making orbital debris a major concern for the operational stability of space assets. This congestion was highlighted by the collision of the Iridium 33 and Cosmos 2251 satellites in 2009. This paper addresses the current state of orbital debris regulation in the United States and asks what might be done through policy change to mitigate risks in the orbital debris environment. A brief discussion of the nature of orbital debris addresses the major contributing factors including size classes, locations of population concentrations, projected satellite populations, and current challenges presented in using post-mission active debris removal to mitigate orbital debris. An overview of the current orbital debris regulatory structure of the United States reveals the fragmented nature of having six regulating bodies providing varying levels of oversight to their markets. A closer look into the regulatory policy of these agencies shows that, while they all take direction from The U.S. Government Orbital Debris Mitigation Standard Practices, this policy is a guideline with no real penalty for non-compliance. Various policy solutions to the orbital debris problem are presented, ranging from a business as usual approach to a consolidated regulation system which would encourage spacecraft operator compliance. The positive aspects of these options are presented as themes that would comprise an effective policy shift towards successful LEO conservation. Potential economic and physical limitations to this policy approach are also addressed. 相似文献
216.
对空战攻防对策力学准则进行了推广研究。导出考虑导弹杀伤半径不为零时的“圆捕获”的界栅方程,该方程表明“点捕获”界栅方程是“圆捕获”界栅方程的特例,给出了捕获区,逃逸区和界栅几何图形,该图形描述了界栅与视线距,视线变化率,视线角速度之间的关系;分析了导弹杀伤半径,导弹和目标机动能力的差值对导弹和目标空战效果的影响。 相似文献
217.
基于PC/104总线的飞机电源产品综合测试系统 总被引:1,自引:0,他引:1
详细介绍了一套基于PC/104总线和虚拟仪器技术的飞机电源产品综合测试系统的功能和软硬件实现原理。阐述了测试系统的设计原理,最后结合整个系统设计介绍了在LabVIEW环境下测试系统软件的设计和实现。 相似文献
218.
针对纳米到皮米量级星间激光测距,在地心非旋转坐标系(GCRS)下,考虑卫星轨道摄动引起的广义相对论效应,建立了星间单向以及双向星间激光相位比对模型.通过仿真研究了地球主引力场范围内轨道摄动引起的广义相对论效应对星间激光相位比对误差的影响,并通过星间激光相位比对误差计算星间激光测距误差.不同轨道高度的卫星仿真结果表明,对... 相似文献
219.
M.T. Menna A. Papitto L. Burderi T. Di Salvo F. DAntona N.R. Robba 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,38(12):2704-2706
We analyze the three outbursts of the X-ray millisecond pulsar SAX J1808.4-3658 that occurred in 1998, 2000, and 2002 observed with RXTE. With a technique based on epoch folding search we find an unique orbital solution valid over the five years of high temporal resolution data available. We revise the estimate of the orbital period, Porb = 7249.1569(1) s and of its error, which we decrease by one order of magnitude. We also give the first constraint on the orbital period derivative, . We find that in 2002 the pulse profile shape is clearly asymmetric, showing a secondary peak at about 145° from the main pulse, which is different from the sinusoidal shape reported at the beginning of the 1998 outburst. 相似文献
220.