Bistatic Radar Cross Sections of Horizontally Oriented Chaff

Bistatic radar cross sections are determined for scattering from a cloud of randomly positioned resonant dipoles (chaff). Dipoles are assumed to be horizontally oriented with axes randomly oriented in the horizontal plane. The cloud is arbitrarily located relative to an illuminating source having an arbitrary (elliptical) polarization. Cloud cross section is found for an arbitrarily located receiver that views the cloud with an antenna of arbitrary polarization. Cross section applicable to the receiver's orthogonal polarization is also found.     

两轮驱动小车系统的设计实现及其路径规划

通过对两轮驱动小车运动模型的分析,设计出了两轮驱动小车的系统。讨论了在环境信息完全已知的情况下,两轮驱动小车的路径规划问题。以凌阳16位单片机SPCE061A为控制器,采用瑞士生产的4Q-DC直流电机具体实现了非完整性的两轮驱动小车系统,通过实验证实了系统设计的有效性,并且完成了期望的路径规划。     

一种新颖的幅频特性测量方法

阐述了一种仅采用信号源和频谱仪两种仪器，测量幅频特性的新颖方法，并给出了一个测量卫星转发器幅频特性的实际例子。     

信道相关性对分集合并接收性能的影响

简介分集接收的主要方式 ,定量分析信道相关性对分集接收性能的影响。特别针对 Rayleigh信道模型中最大比合并和选择合并在各分集支路相关时的性能作了仔细研究 ,给出仿真结果 ,验证各分集支路相关性越小 ,分集效果越好的结论。在最大比合并下 ,当各路平均信噪比与门限相比较小时 ,各分集支路越相关 ,输出信噪比超过门限的概率越大。     

The Role of Wave–Particle Interactions in the Dynamics of Plasma in the Polar Cusp

This paper presents a review of observations of low-frequency plasma waves together with plasma particles performed by Interball 1 and its subsatellite Magion 4 and by the Freja satellite in different cusp regions. The detailed study of the wave spectra together with the electron distribution functions indicates the correlation between the presence of lower-hybrid waves and of particles with energies higher than in the surrounding space. These experimental facts suggest that strong coupling between waves and particles is responsible for plasma heating. The Freja data with a high time resolution allow identification of the process of energy transport via a cascade from low frequency waves to high frequency waves accompanied by electron energization.     

多站连续波雷达的测速定轨方法及应用

本文较详细地介绍了多站连续波跟踪雷达的测速定轨方法，指出了传统测速定轨方法的缺点所在，提出了测速样条函数定轨方法，并应用该方法对弹道测量数据进行了计算处理。理论分析和实际计算表明：该方法精度高，在靶场数据处理中有广泛的应用价值。     

RBCC组合发动机的方案分析和工作模态

介绍了高超声速推进装置的三种工作模态,总结了高超声速推进装置的优缺点,给出了研究重点.     

Effects of prolonged space flight on rat skeletal muscle

The effect of a 20-day space flight on water, Na+, K+, Mg2+, Ca2+ and glycogen contents as well as on activities of glycogen metabolism enzymes--glycogen synthetase and glycogen phosphorylase--of rat skeletal muscles was studied. This data is regarded as an integral test characterizing the state of contractile tissue of the animals at the final stage of flight aboard biosatellites. The measurements indicate that there were no significant changes of cations and glycogen contents nor of the enzymic activities in fast-twitch muscles during the 20-day spaceflight. At the same time dehydration in these muscles was observed, which disappeared on the 25th postflight day. In slow-twitch antigravitational skeletal muscle (m. soleus) there was a decrease of K+ and increase of Na+ in the tissue contents. The changes disappeared at the end of the on-earth readaptation period. From the pattern of these observations, we can conclude that the 20-day space flight leads to some reversible biochemical changes of the rat skeletal muscles. A conclusion can be drawn about necessity of creating, aboard the spaceship, an artificial load on antigravitational skeletal muscles.     

膏体推进剂和固体推进剂药浆稳态燃烧研究

在固体推进剂ＢＤＰ燃烧模型基础上，引入膏体推进剂燃烧效应这一新参数将模型推广于膏体推进剂和固体推进剂药浆燃烧研究，模型考虑了氧化剂粒度分布，组分配比，催化剂性有和膏体推进剂燃烧热效应等对燃速的影响，以及药浆固化有前后燃速差别，还有靶线法测量了某批次复合推进剂药浆固化前后燃速变化，论文结果可用于膏体推进剂的配方和性能预测，以及利用药浆燃速预示固化后推进剂燃速，监控固体推进剂制造质量。     

中国空间用固体火箭发动机的发展

中国从１９５８年开始复合固体推进剂火箭发动机的探索和研制工作。根据航天技术发展的需求，促使复合固体推进剂火箭发动机从小到大逐步发展起来。在三十多年的研制过程中。解决了壳体材料和成型工艺、推进剂配方和装药工艺、喷管和推力向量控制技术，安全点火和高空点火技术、各种环境试验技术、无损检测和质量保证技术、地面试验和测试技术等。已形成了固体火箭发动机研究、设计、试验、生产配套的基本条件，同时为中国卫星发射提