低特征信号绝热层用硅氧烷树脂研究

简述了用于固体火箭发动机低特征信号绝热层研制的发展现状。对多种硅氧烷树脂（ＲＴＶ）进行了筛选和信号透过率，热失重，力学及粘接笥能试验。试验结果表明，与使用ＥＰＤＭ绝热层材料相比，使用ＲＴＶ绝热层材料，火箭发动机燃烧室羽流具有较高的信号透过率；ＲＴＶ还具有较好的热性、力学及粘接性能，适于用作低特征信号绝热层的基体材料。     

MONITORING OF ENERGETIC PARTICLE ENVIRONMENT INSIDE THE CHINA-BRAZIL EARTH RESOURCE SATELLITE

On 14 October 1999, the Chinese-Brazil earth resource satellite (CBERS-1) was launched in China. On board of the satellite there was an instrument designed at Peking University to detect the energetic particle radiation inside the satellite so the radiation fluxes of energetic particles in the cabin can be monitored continuously. Inside a satellite cabin, radiation environment consists of ether penetrated energetic particles or secondary radiation from satellite materials due to the interactions with primary cosmic rays.Purpose of the detectors are twofold, to monitor the particle radiation in the cabin and also to study the space radiation environment The data can be used to study the radiation environment and their effects on the electronics inside the satelhte cabin. On the other hand, the data are useful in study of geo-space energetic particle events such as solar proton events, particle precipitation and variations of the radiation belt since there should be some correlation between the radiation situation inside and outside the satellite.The instrument consists of two semi-conductor detectors for protons and electrons respectively. Each detector has two channels of energy ranges. They are 0.5-2MeV and ≥2MeV for electrons and 5-30MeV and 30-60MeV for protons. Counting rate for all channels are up to 104/(cm2@s)and power consumption is about 2.5 W. There are also the additional functions of CMOS TID (total integrated dose) effect and direct SEU monitoring. The data of CBMC was first sent back on Oct. 17 1999 and it's almost three years from then on. The detector has been working normally and the quality of data is good.The preliminary results of data analysis of CBMC not only reveal the effects of polar particle precipitation and radiation belt on radiation environment inside a satellite, but also show some important features of the geo-space energetic particle radiation.As one of the most important parameters of space weather, the energetic charged particles have great influences on space activities and ground tech nology. CBMC is perhaps the first long-term on-board special equipment to monitor the energetic particle radiation environment inside the satellite and the data it accnmulated are very useful in both satellite designing and space research.     

一种通用的设备转动惯量测量方法

在航天领域的控制系统半实物仿真试验中,经常需要获取某些参试设备的转动惯量以进行姿控系统设计.通常这些设备的形状不规则并且内部质量分布不均,仅采用基于外部形状的三维建模方法难以获得较为精确的转动惯量.本文以某项目地面气浮仿真试验中参试设备转动惯量的测量为应用背景,在GJB361A-97关于三线悬吊法测转子转动惯量的基础上.提出了一种通用的不规则设备的转动惯量测量方法,该方法通过简单的测量步骤对形状不规则、质心不确定、质量分配不均、内部构造复杂等参试设备的转动惯量加以精确测量.测量结果表明,该方法所测转动惯量完全能够满足姿控系统设计的相关指标要求.     

驱动轮结构参数对月球车牵引性能影响研究

研究在月球表面环境下月球车的牵引通过性能,对保证其正常探测工作具有重要意义.根据牵引性能的评价指标,在模拟月壤-车轮土槽测试系统上对不同结构参数的驱动轮牵引性能进行对比试验.结果表明,当增大驱动轮宽度和直径时,其挂钩牵引力和效率系数都呈增大趋势;增大驱动轮的轮刺高度,挂钩牵引力增大;当滑转率小于20%时,效率系数随着轮刺高度的增大而增大,而当滑转率大于20%时,效率系数随着轮刺高度的增大而减小;增大驱动轮轮刺密度时,其挂钩牵引力和效率系数随之先增大后减小.      

基于位置信息的HMIPv6快速切换方案

针对RSVP在HMIPv6下域间(inter-handover)切换延时过大,不能满足实时业务的要求。本文提出一种基于位置信息的HMIPv6快速切换方案,即移动节点进行域间切换时,根据移动节点的运动轨迹预测即将去往的接入路由器,从而提前注册及预留资源。     

热处理及晶粒组织对2A55超高强铝锂合金板材各向异性的影响

采用室温拉伸力学性能测试、X射线织构检测、EBSD分析等方法,对比研究了10 mm与2 mm厚度2A55超高强铝锂合金板材的平面各向异性,阐释热处理制度与晶粒组织对板材各向异性的影响。结果表明,热处理后板材屈服强度最高的取向为轧向（0°）与横向（90°）;Taylor因子能较好地预测固溶态与T6态时效板材屈服强度的各向异性,织构是平面各向异性的重要原因;厚板更高含量的织构与长条状的晶粒形貌导致其各向异性强于薄板;时效热处理使10 mm厚度板材各向异性减弱,使2 mm厚度薄板各向异性增强;T3态、T8态板材的各向异性分别强于T4态、T6态,时效前的预变形增强了板材的平面各向异性。     

微量气味成分的自由基簇射技术脱除

研究了密闭体系中微量气味污染物的脱除作用与机理。采用电晕放电自由基簇射技术，实现了人工环境下氧化性自由基的产生；以电子自旋共振技术（ESR）对气态羟基自由基实施了捕集和检测，验证了在羟基自由基的存在下NH3被氧化为N2。通过U—I获得反应能耗和污染物去除效率为：NH3脱除效率为90．6％时，能耗1．0W。研究表明：自由基簇射技术产生的氧化性自由基可有效去除密闭生存环境中产生的NH3等微量有害气味成分，将在空间站等密闭生存系统内空气净化中有很好的应用前景。     

五边平行进近冲突风险定量分析模型

针对飞机五边平行进近时飞行冲突,提出了一种五边平行进近飞行冲突定量分析模型。模型通过飞机在任意时刻的标称位置坐标与因不确定性因素导致的航迹偏移量之和,形成飞机任意时刻真实位置坐标,基于此推导出飞机在五边平行进近时冲突风险计算公式。在分析不确定性因素导致航迹偏离时,提出了一种基于布朗运动的随机过程来描述因干扰因素导致飞机随机运动的方法。在建立模型后,使用蒙特卡罗仿真方法计算了飞行冲突概率,结果理想。     

自动细分多齿分度台的研制

采用可编程多轴运动控制卡实现对细分多齿分度台的自动控制,通过在细分机构中加入光栅作为位置反馈,提高了细分角度的准确度,从而提高了仪器的整体准确度。     

“超黄蜂”直升机飞行事故探讨

对"超黄蜂"发生的一起严重飞行事故,理论结合实践,从影响直升机飞行状态的关键系统和动部件入手,探讨飞行事故原因,分析了由于空中出现意外情况,飞行员操纵不当,直升机进入涡环,飞行员不自觉改出涡环,迫降失败。本事故的教训对"超黄蜂"(或直八)、"海豚"(或直九)直升机的飞行和维护保障都有一定的意义。