Application of China–Brazil Earth resources satellite in China

The launch and successful operation of Chinese–Brazil Earth resources satellite (CBERS-1) in China has accelerated the application of space technology in China. These applications include agriculture, forestry, water conservation, land resources, city planning, environment protection and natural hazards monitoring and so on. The result of these applications provides a scientific basis for government decision making and has created great economic and social benefits in Chinese national economy construction. In this paper we present examples and provide auxiliary documentation of additional applications of the data from Earth resource monitoring.     

Infrared radiation signature of exhaust plume from solid propellants with different energy characteristics

The infrared radiation signature of the plume from solid propellants with different energy characteristics is not the same. Three kinds of double-base propellants of different energy characteristics are chosen to measure the infrared spectral radiance from 1000 cm 1 to 4500 cm 1 of their plumes. The radiative spectrum is obtained in the tests. The experimental results indicate that the infrared radiation of the plume is determined by the energy characteristics of the propellant. The radiative transfer calculation models of the exhaust plume for the solid propellants are established. By including the chemical reaction source term and the radiation source term into the energy equation, the plume field and the radiative transfer are solved in a coupled way. The calculated results are consistent with the experimental data, so the reliability of the models is confirmed. The temperature distribution and the extent of the afterburning of the plume are distinct for the propellants of different energy characteristics, therefore the plume radiation varies for different propellants. The temperature of the fluid cell in the plume will increase or decrease to some extent by the influence of the radiation term.     

基于使命任务分解的航空电子跨平台通信组织与仿真

在先进的综合化航空电子系统设计中,跨平台通信的组织将直接体现使命任务的需求。通过功能流程框图将航空电子系统使命任务各个阶段分解为功能组件,给出了一种功能组件之间跨平台信息交互的组织方法,并采用移动自组织通信的方式实现。将某任务片段中的空中图像信息传输作为模拟案例,使用OPNET软件进行仿真研究。仿真结果表明,该方法根据任务的特性设定平台之间的动态通信过程,与没有经过使命任务分解设计的对照组相比,在同等发射功率下能够有效地降低误码率。     

应答式无线报警系统

应答式无线报警系统是一套规范化无线报警设备,它采用了MCS—51单片微机作为控制,从而使系统具有电路简单、性能可靠、控制灵活、成本低廉、操作简单、信息指示直观明了等特点,具有较强的科学性和先进性。     

Influence of thermal inhibitor position and temperature on vortex-shedding-driven pressure oscillations

Vortex-acoustic coupling is one of the most important potential sources of combustion instability in solid rocket motors (SRMs). Based on the Von Karman Institute for Fluid Dynamics (VKI) experimental motor, the influence of the thermal inhibitor position and temperature on vortex-shedding-driven pressure oscillations is numerically studied via the large eddy simulation (LES) method. The simulation results demonstrate that vortex shedding is a periodic process and its accurate frequency can be numerically obtained. Acoustic modes could be easily excited by vortex shedding. The vortex shedding frequency and second acoustic frequency dominate the pressure oscillation characteristics in the chamber. Thermal inhibitor position and gas temperature have little effect on vortex shedding frequency, but have great impact on pressure oscillation amplitude. Pressure amplitude is much higher when the thermal inhibitor locates at the acoustic velocity anti-nodes. The farther the thermal inhibitor is to the nozzle head, the more vortex energy would be dissipated by the turbulence. Therefore, the vortex shedding amplitude at the second acoustic velocity antinode near 3/4L (L is chamber length) is larger than those of others. Besides, the natural acoustic frequencies increase with the gas temperature. As the vortex shedding frequency departs from the natural acoustic frequency, the vortex-acoustic feedback loop is decoupled. Consequently, both the vortex shedding and acoustic amplitudes decrease rapidly.     

单向碳／碳复合材料的蠕变内应力

用应力降落法测定单向ＰＡＮ基碳纤维Ｔ３００增加热碳基复合材料在１９００－２３５０℃蠕变内应力σ０，结果及分析表明，对单向Ｃ／Ｃ复合材料，σ０不是一个材料常数，而是温度Ｔ、初始力σｓ及结构因子Ｓ的函数，即σ０＝σ０（ｔ，σｓ，Ｓ）。     

自适应两步滤波器及其在导弹被动制导中的应用

两步滤波器由Ｋａｌｍａｎ滤波器和Ｇａｕｓｓ－Ｎｅｗｔｏｎ迭代算法所构成，它适用于一类由线性动态模型和非线性测量模型所组成的非线性系统。本文将这种滤波器与时变测量噪声统计估值器相结合，得到一种自适应两步滤波器，在测量噪声统计特性无法验前已知的情况下，此滤波器仍然性能良好。最后，本文将自适应两步滤波器应用于导弹的被动制导问题，数字仿真结果证明了这种算法的有效性。     

关于航空气象建设发展的几点思考

今年，特别是8月份以来，世界各地接二连三的空难事故给人民的生命财产带来极大的损失，同时也对各国航空业造成极大的冲击。分析今年伤亡人数超过100人的五起空难事故，发现2月3日阿富汗喀布尔市坠机事故和8月24日秘鲁亚马逊市坠机事故当时都出现恶劣天气现象，恶劣天气很可能就是造成飞行事故的直接原因。据国际航空组织统计分析，天气原因是造成飞行事故和航班延误的首要原因，其概率远大于机械原因、环境因素、人为因素等各类原因，由此可见，准确的天气预报对保证飞行安全、提高航班正常率具有重要意义。     

XML技术在航空电子接口控制中的应用前景

对航空电子系统内部的信号与信息进行描述、配置与管理是航空电子综合设计中的重要内容。本文通过对可扩展置标语言(XML)的技术特点及其在设备管理专业领域已有的应用分析,探讨了XML技术对于航空电子接口设计与管理中的应用前景;并对XML技术与数据库技术在航电设计中的区别与联系,以及XML在接口控制文件(ICD)编制、管理和分发中的应用进行了论证。     

基于EWMA的计算机辅助质量控制系统

对传统的质量控制算法和常规计算机质量控制算法进行了比较,把它们统一起来,并提出了一个变形了的EWMA质量控制算法,推导验证了其无偏估计量,分别针对抛弃和非抛弃两种形式求出了各自递推表达式。最后设计了一个基于EWMA计算机辅助质量控制系统,并据此进行了实验仿真。