气冷内窥式高温电视监控系统

结合工程实践对典型的高温电视系统的主要部分作一介绍.反映了应用电视技术从最初关注单机技术、单纯硬件到注重在各种环境下应用的防护设计、系统设计及朝着与计算机、视频信号处理、报警技术相结合的发展趋势.该种气冷内窥式高温工业电视系统已在宝钢及多家火力发电厂投入使用.     

高密度通信信号环境模拟

随着通信技术的发展和使用的日益普及 ,新的设备面临的信号环境也日益复杂 ,为了能够充分检测通信设备和电波监测设备对复杂通信信号环境的适应性 ,必须建立高密度动态的通信信号测试环境。文中探讨采用任意波形发生器产生高密度多路通信信号测试环境的方法     

环境建设与城市发展的探讨

环境建设在城市发展中至关重要。廊坊市在处理环境建设与城市发展关系，促进廊坊协调可持续发展几个方面进行了实践探索。     

多卫星环境下的空时发射分集技术

分析了宽带码分多址多卫星通用移动电信系统(UMTS)环境前向链路中应用的一些不同分集方案空时码性能。为实现空时Turbo编码调制(STTCM)，采用了卷积码(CC)和迭代译码，并在两卫星环境下对不同发送方案进行了模拟。结果显示，在低信噪比(sNR)时，选择式发射分集(STD)的误码率(BER)和误帧率(FER)优于其他方案。随着SNR的增大，空时格码(STTC)(未编码系统)和STTCM(编码系统)的FER最佳。     

微机的运行环境及其常规性维护

本文对影响微机运行的环境因素加以简要分析，并介绍一些微机常规性维护的要点和方法，以确保微机的正常工作和数据的安全。     

Collision Probabilities for Keplerian Orbits

We present a new derivation of the probability of collisions between spherical satellites occupying Keplerian orbits. The equations follow from the central concept of the instantaneous collision rate, an expression that describes the occurrence of collisions by using a Dirac -function. The derivation proceeds by showing how this instantaneous collision rate can be averaged over orbital mean anomaly angles and, additionally, over orbital precession angles to generate expressions appropriate for intermediate and long time scales. Collision rates averaged over mean anomalies tend to be non-zero during relatively brief collision seasons, when the peak collision probability may exceed the long-term average by several orders of magnitude. Derived precession-angle averages have a functional form similar but not identical to the collision probability expression derived using the spatial density approach of Kessler (Icarus, 48: 39–48, 1981), and the two methods have been found to yield numerical results to within 1% for all cases examined.     

航天器载人试验舱的设计

介绍了载人试验舱的结构特点、有限元计算及载人试验舱几个主要的部件。     

分子筛氧气浓缩器产氧性能实验分析

根据"变压-吸附-解吸附" 压力交变原理,研制了分子筛氧气浓缩器样机.通过不同入口压力、输出流量、高空压力和温度环境实验,测试了分子筛浓缩器样机的制氧性能.结果表明,分子筛氧气浓缩器样机产氧浓度随入口压力和上升高度的增加而增加;随输出流量的增加而减少;升降速度、环境温度影响不大.系统产氧性能基本满足系统工程生理学防护要求,其性能与国外产品有可比性.     

载人舱不锈钢—铜热沉的设计

热沉不但具备模拟宇宙的“冷黑”环境功能,而且还相当于一个辐射换热器和抽气泵,由此引出热沉材料的选择原则。文章详细介绍了不锈钢－铜热沉的设计和测试结果,说明了不锈钢－铜热沉的设计为热沉的发展开辟了一条新途径。     

Solar particle events observed at Mars: dosimetry measurements and model calculations

During the period from March 13, 2002 to mid-September, 2002, six solar particle events (SPE) were observed by the MARIE instrument onboard the Odyssey Spacecraft in Martian Orbit. These events were observed also by the GOES 8 satellite in Earth orbit, and thus represent the first time that the same SPE have been observed at these separate locations. The characteristics of these SPE are examined, given that the active regions of the solar disc from which the event originated can usually be identified. The dose rates at Martian orbit are calculated, both for the galactic and solar components of the ionizing particle radiation environment. The dose rates due to galactic cosmic rays (GCR) agree well with the HZETRN model calculations.