环境温湿度对蜂窝增强硅橡胶基低密度烧蚀材料硬度的影响

介绍了环境温湿度以及促进剂用量、酸酐用量对窝增强硅橡胶基低密度烧蚀材料硬度的影响。试验发现蜂窝增强硅橡胶基低密度烧蚀材料硬度沿厚度方向呈规律变化：从外向里材料硬度逐渐降低,室温存放时间长的材料硬度降低的梯度小;密度小的材料硬度降低梯度小;促进剂量多的材料硫化后材料表面硬度大,从外向里硬度降低梯度大。其酸酐用量最佳起来 环氧树脂的３０％（质量分数）。     

21世纪初固体推进剂技术展望

从高能、低特征信号、能量管理型及含硼富燃料推进剂等主要方面综述了各国近年来在固体推进剂技术方面的最新进展,分析展望了固体推进剂技术２１世纪初发展的趋势及主要技术方向,并提出了预测性的看法。     

高温相变单元管蓄热过程数值模拟

对以高温共晶盐 Li F-Ca F2 为相变材料 (PCM)和以干空气为工质的相变蓄热系统 ,采用焓方法建立了以控制体单元为对象的单管相变蓄热模型。在模拟空间站太阳能吸热 /储热器轨道运行参数下进行了数值计算。计算结果与地面模拟试验数据进行了比较 ,吻合良好。     

Composition Variations in the Solar Corona and Solar Wind

Order of magnitude variations in relative elemental abundances are observed in the solar corona and solar wind. The instruments aboard SOHO make it possible to explore these variations in detail to determine whether they arise near the solar surface or higher in the corona. A substantial enhancement of low First Ionization Potential (FIP) elements relative to high FIP elements is often seen in both the corona and the solar wind, and that must arise in the chromosphere. Several theoretical models have been put forward to account for the FIP effect, but as yet even the basic physical mechanism responsible remains an open question. Evidence for gravitational settling is also found at larger heights in quiescent streamers. The question is why the heavier elements don't settle out completely. This revised version was published online in June 2006 with corrections to the Cover Date.     

UVCS/SOHO Observations of Spectral Line Profiles in Polar Coronal Holes

Ultraviolet emission line profiles have been measured on 15-29 September 1997 for H I 1216 Å, O VI 1032, 1037 Å and Mg X 625 Å in a polar coronal hole, at heliographic heights ? (in solar radii) between 1.34 and 2.0. Observations of H I 1216 Å and the O VI doublet from January 1997 for ? = 1.5 to 3.0 are provided for comparison. Mg X 625 Å is observed to have a narrow component at ? = 1.34 which accounts for only a small fraction of the observed spectral radiance, and a broad component that exists at all observed heights. The widths of O VI broad components are only slightly larger than those for H I at ? = 1.34, but are significantly larger at ? = 1.5 and much larger for ? > 1.75. In contrast, the Mg X values are less than those of H I up to 1.75 and then increase rapidly up to at least ? = 2.0, but never reach the values of O VI.     

基于力矩比优化的航天员舱外活动仿真

提出了一种基于力矩比优化的航天员人体运动控制算法,该算法综合考虑了反向运动学、反向动力学以及人体工效学等因素,避免了单纯从动力学方面求解所带来的虚拟人体动画所隐含的力量冲突,提高了仿真结果的真实性和合理性。研究结果可为航天员舱外活动的设计和考察提供一定的理论指导和技术支持。     

太阳能火箭发动机聚光器设计方法

对工程上常用聚光器进行了性能比较,得出了适合于太阳能火箭发动机(STP)的聚光器及其具有的性能优点,研究了此种聚光器的的设计方法,并推出了相关公式和其中的关键技术,这对STP聚光器的工程设计具有重要的指导价值。      

Solar and Solar-Wind Composition Results from the Genesis Mission

The Genesis mission returned samples of solar wind to Earth in September 2004 for ground-based analyses of solar-wind composition, particularly for isotope ratios. Substrates, consisting mostly of high-purity semiconductor materials, were exposed to the solar wind at L1 from December 2001 to April 2004. In addition to a bulk sample of the solar wind, separate samples of coronal hole (CH), interstream (IS), and coronal mass ejection material were obtained. Although many substrates were broken upon landing due to the failure to deploy the parachute, a number of results have been obtained, and most of the primary science objectives will likely be met. These objectives include He, Ne, Ar, Kr, and Xe isotope ratios in the bulk solar wind and in different solar-wind regimes, and ¹⁵N/¹⁴N and ¹⁸O/¹⁷O/¹⁶O to high precision. The greatest successes to date have been with the noble gases. Light noble gases from bulk solar wind and separate solar-wind regime samples have now been analyzed. Helium results show clear evidence of isotopic fractionation between CH and IS samples, consistent with simplistic Coulomb drag theory predictions of fractionation between the photosphere and different solar-wind regimes, though fractionation by wave heating is also a possible explanation. Neon results from closed system stepped etching of bulk metallic glass have revealed the nature of isotopic fractionation as a function of depth, which in lunar samples have for years deceptively suggested the presence of an additional, energetic component in solar wind trapped in lunar grains and meteorites. Isotope ratios of the heavy noble gases, nitrogen, and oxygen are in the process of being measured.     

太阳能飞机翼肋结构拓扑优化设计

太阳能飞机翼肋结构轻薄且数量众多,其结构形式的合理性对于结构减重、机翼刚度设计等具有重要意义。基于现有太阳能飞机翼肋的结构形式,提出一种翼肋拓扑优化设计方法:首先,应用双向渐进结构优化法(BESO),以单元应力为判断指标,对太阳能飞机典型翼肋进行结构拓扑优化;其次,基于拓扑优化结果对翼肋进行结构细节设计;最后,通过有限元计算,验证翼肋的结构强度、刚度和静稳定性。通过本文方法,能够得到太阳能飞机翼肋更为合理的结构布局。     

一种弹性低密度耐高温隔热涂层

针对固体火箭发动机实际使用的热环境要求,研制了一种弹性低密度耐高温隔热涂层,通过石英 灯辐射和电弧风洞试验对其进行了防热性能考核。该涂层密度为0. 62 g/ cm3,伸长率为25%,热导率为0． 18 W/ (m·K);在401℃时DSC 失重率仅为6. 6%;验证考核表明,采用1. 0 mm 涂层时,壳体与涂层界面温度最高 为77. 3℃,壳体背温度最高为44. 5℃。