环境试验数据和控制系统技术:过去、现在、将来

Michellich先生毕业于堪萨斯大学,获得博士学位。他1966年进入波音公司。他曾搞过土星V的仪表系统试验,S—IC级靜态点火数据处理,研究随机和瞬态数据处理程序、研究振动控制系统软件。现在他在波音航空工程实验室负责研制新的数据收集,试验控制和数据处理系统。     

Cell-to-cell interactions in changed gravity: ground-based and flight experiments

Cell-to-cell interactions play an important role in all physiological processes and are mediated by humoral and mechanical factors. Mechanosensitive cells (e.g., osteocytes, chondrocytes, and fibroblasts) can be studied ex vivo to understand the effects of an altered gravity environment. In particular, cultured endothelial cells (EC) are very sensitive to a broad spectrum of mechanical and biochemical stimuli. Earlier, we demonstrated that clinorotation leads to cytoskeletal remodeling in cultured ECs. Long-term gravity vector changes also modulate the expression of surface adhesion molecules (ICAM-1, E-selectin, VCAM-1) on cultured ECs. To study the interactions of geterological cells, we cocultured endothelial monolayers and human lymphocytes, immune cells and myeloleucemic (K-560) cells. It was found that, although clinorotation did not alter the basal adhesion level of non-activated immune cells on endothelial monolayers, the adhesion of PMA-activated lymphocytes was increased. During flight experiments onboard the Russian segment of the International Space Station, we measured the cytotoxic activity of natural killer (NK) cells incubated with labeled target cells. It was found that immune cells in microgravity retained their ability to contact, recognize, and destroy oncogenic cells in vitro. Together, our data concerning the effects of simulated and real microgravity suggest that, despite changes in the cytoskeleton, cell motility, and expression of adhesion molecules, cell-cell interactions are not compromised, thus preserving the critical physiological functions of immune and endothelial cells.     

Production of oxidants by ion irradiation of water/carbon dioxide frozen mixtures

We present new experimental results on the formation of oxidants, such as hydrogen peroxide, ozone, and carbonic acid, under ion irradiation of icy mixtures of water/carbon dioxide at different ratios and temperatures (16 and 80 K). Pure water ice layers and mixtures with carbon dioxide were irradiated by 200 keV He+ ions. We found that the CO(2)/H(2)O ratio progressively decreased to a value of about 0.1, the H(2)O(2) production increased with increasing CO(2) abundance at both 16 and 80 K, and the CO and H(2)CO(3) production increased with increasing CO(2) abundance at 16 K. At 80 K, the synthesis of CO was less efficient because of the high volatility of the molecule that partially sublimed from the target. The production of carbonic acid was connected with the production of CO(3). O(3) was detected only after ion irradiation of CO(2)-rich mixtures. The experimental results are discussed with regard to the relevance they may have in the production of an energy source for a europan or a martian biosphere.     

常见寿命分布组件初始贮存方案评估及优化

针对"长期贮存,一次使用"装备初始贮存方案评估及优化问题,分析了常见寿命分布组件的可靠度模型,建立了贮存期内组件及装备完好数量评估模型;以达标概率指标为约束条件,组件初始购置费用为优化目标,建立了组件初始贮存方案优化模型,提出了基于边际效益值的优化方法,开展了算法复杂性分析。算例分析表明,所建初始贮存方案评估模型的评估精度较高,优化后的初始贮存方案能够在满足达标概率要求的同时,使得组件购置费用最低。边际优化算法在保持计算精度的同时有效提高了计算效率。提出的模型和优化算法能够为装备保障人员制定合理的装备单元贮存方案提供决策支持。     

风洞投放试验技术的研究现状与应用综述

多体分离是航空、航天和武器系统总体部门一直极为关注的关键问题,多体间的流场干扰效应产生的气动力和力矩对悬挂物分离相容性有重要影响,基于运动动力学相似的风洞投放试验技术是预测和评估多体分离是否相容的一种非定常试验方法。根据飞行器多体分离相容性的研究需求,结合作者在风洞投放试验技术的研究成果和经验,对风洞投放试验技术的国内外研究现状进行综述。首先回顾了风洞投放试验技术的发展历史,然后对低速和高速风洞投放试验的相似准则及缩比关系进行详细地论述与分析,进而对风洞投放试验的几个关键技术进行综述,最后对风洞投放试验技术存在的问题提出思考与展望。     

一体化太阳敏感器热分析与验证方法

为保证太阳敏感器在进行光电一体化设计后的光学系统热稳定性,满足电子元器件的工作温度降额要求,采取光学模型与热模型相结合的热分析方法,得出了包括光学组件在内的整机温度分布数据.采用温度边界设定结合太阳光外热流的热平衡试验方法对产品实际温度分布情况进行验证,结果表明一体化太阳敏感器在壳体温度达到55℃,且受到1太阳常数太阳光照射时,仍满足设计要求,且测试数据和分析结果吻合.     

带有中心钝体的固体燃料冲压发动机工作性能分析

为提高固体燃料冲压发动机的燃烧特性和工作性能,提出了带有中心钝体的固体燃料冲压发动机方案,基于雷诺转捩和涡概念耗散方程建立了其湍流燃烧模型,并数值计算分析了其内流场、燃面退移速率、推力与总压损失。结果表明：带有中心钝体的冲压发动机内部流动过程较为复杂,钝体后部有四个漩涡,增强了发动机内来流空气与燃气的掺混;钝体孔隙中的高速气流与两侧的小尺度漩涡保证了钝体尾涡的稳定性;与普通固体燃料冲压发动机相比,在燃烧室中增加中心钝体能增大燃烧室内高温区面积,提高补燃室内温度,可使推进剂平均燃面退移速率提高26.11%,发动机推力提高22.12%,燃烧效率提高8.9%。     

用于石英谐振器研究的频域反射计

本文介绍一种用于精确测量石英晶体谐振频率特性的调相频域反射计系统的概念和工作原理。反射计法容许被测晶体谐振器远置于一环境试验箱中;这系统还能同时而又单独地对任一给定晶体中发生的不同谐振模(例如,SC切晶体中的b模和c模谐振)进行频率测量。这一反射计技木主要适用于对谐振器进行以下基本研究:频率一温度特性的研究;滞后现象和热冲击效应的研究;幅度一频率因数和多模激励特性的研究以及核幅射效应的研究,等等。本仪器也可应用于晶体生产过程,包括自动化生产、测试以及质量控制等。