层板推力室再生冷却通道的传热特性分析

提出液体火箭发动机层板推力室再生冷却通道传热过程的数理模型。采用通用形式控制方程处理冷却剂紊流换热和通道材料导热的共轭传热问题，计算采用LVEL紊流模型，并考虑冷却剂（氢）的热物性参数随温度和压力的变化及层板材料热物性随温度的变化。结果表明，采用大高宽比、小气壁厚度的通道设计，可显著提高再生冷却能力，降低室壁温度和温差。采用对流换热系数和热物性为常数的简化处理会引起很大误差。     

Temporal evolution of the RCS of aircraft wake vortices

Knowledge of the radar scattering characteristics is one of the key issues for the development of wake vortex detection technology. This paper studies the temporal evolution of the RCS (radar cross-section) of wake vortices. The RCS–time plot is observed to increase as a whole and step at a certain time. These properties could provide help to the design of wake vortex detection radar and the optimization of radar station layout. The special spiral structures within the wake, together with the Bragg scattering theory, are used to well explain these phenomena, and some representative radar experiments are also included to verify them.     

某型飞机燃油测量系统研究

结合部队装备部门的实际需要,针对某型飞机燃油测量系统的现状,采用以DSP为核心的燃油测量系统方案,对原系统进行了改进和升级,从而使飞机燃油测量系统的性能得到了提高.     

两米光栅—线纹自动测量仪测量不确定度的评定(一)

以不确定度的概念对两米光栅—线纹自动测量仪的测量质量、水平进行了评定，给出了该仪器测量光栅尺和线纹尺的不确定度指标。     

基于目标导向的连续型机器人路径规划

采用连续型机器人对空间约束严格的飞机油箱进行检查,研究了其在类似凸体空间内的路径规划问题,提出一种基于目标导向的规划算法.针对空间盲目搜索算法时间复杂度高问题,研究降维和区域划分策略.引入目标导向角,建立目标点与变量搜索范围的关系,优化搜索过程并设计评价函数对搜索结果寻优.进行仿真实验,结果验证了算法的可行性和有效性.     

Temporally staggered sensors in multi-sensor target tracking systems

For a multi-sensor target tracking system, the effects of temporally staggered sensors on system performance are investigated and compared with those of synchronous sensors. To capture system performance over time, a new metric, the average estimation error variance (AEV), is proposed. For a system that has N sensors with equal measurement noise variance, numerical results show that the optimal staggering pattern is to use N uniformly staggered sensors. We have also shown analytically that the AEV of the system with N uniformly staggered sensors is always smaller than that of the system with N synchronous sensors. For sensors with different measurement noise variances, the optimal staggering pattern can be found numerically. Practical guidelines on selecting the optimal staggering pattern have been presented for different target tracking scenarios. Due to its simplicity, uniform staggering can be used as an alternative scheme with relatively small performance degradation.     

醉步石海洞乡

北京时间2005年2月11日23时48分，巴黎当地时间16时48分，从遥远的法国巴黎世界地质公园大会传来了令人振奋的消息，“兴石海地质公园”成功通过世界地质公园大会委员会最后评审，成为第二批世界地质公园。     

中国第一座桥梁风洞的研制

同济大学土木工程防灾国家实验室于1994年10月建成一座可供全桥模型试验的大型桥梁风洞，试验段14m×15m×2m（长×宽×高）。风洞的总体布局及结构安排突出地强调了非航空类风洞的特点，结构上采用砖混结构与钢结构相结合的方法，并以砖混结构为主，这就大大的缩短了建造周期，降低了成本。建成后的桥梁风洞总体造型美观并具有良好的气流品质，达到或超过了原设计中的性能指标，为我国桥梁建造业填补了空白。     

载人航天器压力应急环境着火危险性试验研究

载人航天器在压力应急环境下处于低压高浓度氧环境。为了分析该环境下载人航天器在太空中飞行以及地面模拟试验中的着火危险性,研制了低压高浓度氧环境着火试验装置,并进行了燃烧试验。对载人航天器压力应急环境下材料的燃烧速度和点火能量等因素进行分析研究,得到了压力应急工况的材料着火和燃烧的规律,并给出了火灾防范的建议。