火箭发射防雷问题

雷电效应对火箭发射可能产生破坏作用，在雷雨季节运载火箭发射时，所采取的一些防雷电措施，在本文中作了介绍。     

导弹垂直发射中二次流流场计算

本文应用Ｇｏｄｕｎｏｖ方法对导弹垂直发射系统的内流场进行了数值模拟，详细描述了导弹点火后二次流的形成及其对弹体的影响，为导弹的设计和发射系统的热防护提供参考。     

新型四余度功率电传推力矢量控制技术

通过对现有不同类型功率电传(PBW—Power by wire)系统进行分析,根据航天运载器使用特点,提出了理想PBW系统的概念,并基于负载敏感原理提出了新型PBW系统方案。在此基础上,针对载人航天等高可靠性应用场合,提出了四余度PBW系统方案。通过仿真研究证明所提出的新型PBW系统具有比传统PBW系统更好的综合性能,是最接近于理想PBW系统的设计方案。通过对四余度PBW系统在故障情况下的工作情况进行仿真研究表明,四余度PBW系统具有两次故障工作、三次故障安全的余度等级。文中所提出的系统方案在未来大推力固体火箭发动机和氢氧发动机推力矢量控制系统中具有广泛的应用前景。     

垂直射流混合的三维湍流数值模拟

采用三维ＳＩＭＰＬＥ程序和ｋ－ε双方程湍流模型对三维受限垂直射流进行数值模拟,研究了不同的几何变量和流动参数对射流穿透和混合的影响。模拟结果表明,三维垂直射流最显著的流动特征是形成了流向旋涡。射流与来流的混合程度取决于旋涡的位置、作用范围和强弱。单股射流随动量比、旋涡强度和尺度的增加,混合增强。对于单排多股射流,喷孔间距直接影响旋涡涡心位置。密排射流,旋涡过于靠近下壁面,旋涡无法影响上面来流;但喷孔排列也不能过于稀疏,否则涡对靠的太近,旋涡对侧面影响不大。Ｓ／Ｈ和动量比不变,改变孔径Ｄ对射流穿透几乎无影响。这一重要结论说明Ｓ／Ｈ和Ｊ是决定多股受限射流穿透深度的最重要的量。     

Expectations for Crater Size and Photometric Evolution from the Deep Impact Collision

The NASA Discovery Deep Impact mission involves a unique experiment designed to excavate pristine materials from below the surface of comet. In July 2005, the Deep Impact (DI) spacecraft, will release a 360 kg probe that will collide with comet 9P/Tempel 1. This collision will excavate pristine materials from depth and produce a crater whose size and appearance will provide fundamental insights into the nature and physical properties of the upper 20 to 40 m. Laboratory impact experiments performed at the NASA Ames Vertical Gun Range at NASA Ames Research Center were designed to assess the range of possible outcomes for a wide range of target types and impact angles. Although all experiments were performed under terrestrial gravity, key scaling relations and processes allow first-order extrapolations to Tempel 1. If gravity-scaling relations apply (weakly bonded particulate near-surface), the DI impact could create a crater 70 m to 140 m in diameter, depending on the scaling relation applied. Smaller than expected craters can be attributed either to the effect of strength limiting crater growth or to collapse of an unstable (deep) transient crater as a result of very high porosity and compressibility. Larger then expected craters could indicate unusually low density (< 0.3 g cm⁻³) or backpressures from expanding vapor. Consequently, final crater size or depth may not uniquely establish the physical nature of the upper 20 m of the comet. But the observed ejecta curtain angles and crater morphology will help resolve this ambiguity. Moreover, the intensity and decay of the impact “flash” as observed from Earth, space probes, or the accompanying DI flyby instruments should provide critical data that will further resolve ambiguities.     

导弹发射车带主机发电的方法

根据一般导弹发射车电源供电的形式和集中供电存在的弊端，提出了导弹发射车主机发电的研究课题，即利用导弹发射车自身行驶用的汽车发动机作为原动力，通过能量转换，变成导弹发射车所需的一次电源。介绍了实现主机发电的技术难点，及为解决这些技术难点所采取的技术措施。实际应用表明，主机发电除具有重量轻、体积小外，还保持了原有的操作位置，克服了集中供电的不足。     

半主动寻的中程舰空导弹复合制导控制技术概述

介绍了采用垂直发射捷联惯导＋修正指令＋半主动寻的复合制导体制，并对所涉及的一系列制导与控制方面的技术关键及难点进行了讨论。     

便携式防空导弹扩展使用探讨

结合便携式超低空防空导弹的特点，论述了扩展使用的必要性，并参考国外同类导弹的应用情况，提出了扩展使用的设想及实现的初步方案。在扩展使用的实现途径中，根据实战需要和技术发展状况，提出了采取分阶段实现的原则，并重点分析了制约便携式防空导弹向高级阶段发展的口盖、弹筒约束解除、捕获能力、光轴指向等问题及解决问题的初步方案。     

箱式垂直发射系统燃气流的排导

阐述了箱式垂直发射系统燃气流合理排导的必要性。在对内导流和外导流两种燃气流排导方式进行分析比较的基础上，指出了燃气流外排导的局限性。认为燃气流内排导由于具备结构简单、空间利用率高、通用性强、安全性高等优点，适合于垂直发射燃气流的合理排导；尤其是同心筒式发射装置燃气流的排导将成为箱式眚发射系数燃气流排导的发展方向。     

Use of principal component analysis in the identification of the spatial pattern of an ionospheric total electron content anomalies after China’s May 12, 2008, M = 7.9 Wenchuan earthquake

This paper uses principal component analysis (PCA) to determine the spatial pattern of total electron content (TEC) anomalies in the ionosphere post the China’s Wenchuan Earthquake of 12 May, 2008 (UTC) (M_w = 7.9). PCA and image processing are applied to the global ionospheric map (GIM) with transforms conducted for the time period 08:00–10:00 UT on 12 May 2008. Results show that at a height of approximately 200 km the anomaly is widespread and less intense; however, it becomes more localized with height reaching maximum intensity and localization at an altitude of 300 km. The spatial distribution is remarkably similar to that reported for a TEC anomaly previously identified as a precursor anomaly on May 9, 2008 for the same time period. Potential causes of the results are discussed with emphasis given to vertical acoustic gravity waves based on the spatial pattern identified.