合成孔径雷达在飞行器组合导航系统中的应用

合成孔径雷达(ＳＡＲ)是雷达理论和技术发展到一定阶段的基础上诞生的一种具有很高分辨率的成像雷达。它在众多领域得到了广泛的应用。在飞行器组合导航系统中,利用ＳＡＲ图像进行图像匹配,可以极大地提高系统的导航精度。本文介绍了ＳＡＲ、组合导航系统的发展及研究现状。重点介绍了ＳＡＲ在飞行器组合导航系统中的应用,并给出了具有较高精度、容错性和自主性的ＩＮＳ/ＧＮＳＳ/ＳＡＲ组合导航系统的原理、结构及仿真结果。     

软件项目估算与测量的工程实践

在开发过程中软件估算和测量非常重要,如果没有合理而准确的估算和实测数据,就不能对软件项目进行有效的管理和控制。本文阐述了在航天软件过程改进实施过程中工作产品规模、工作量和进度的估算和测量方法,分析了3个航天软件项目的测量结果,总结了项目的管理情况。并且证明基本的CO-COMO模型比较适合航天软件项目。     

空间技术中的控制理论与应用的现状及发展

本文结合我国空间事业发展现状,概述了现代控制理论在我国空间技术领域的应用现状,描述了现代控制理论对空间控制技术的应用前景,最后指出如何结合我国空间事业的发展开展现代控制理论的应用研究。     

气动伺服弹性综合的应用

在气动伺服弹性技术综合方面开展了如下的研究：气动伺服弹性的建模；控制律的综合设计；自适应控制的可行性；主动控制系统的鲁棒稳定性；以及控制律的工程评估等综合问题。这些问题的讨论，都在同一算例上实施的，实验或计算的结果，都可相互对照比较。     

基于有限元的螺栓弯曲强度分析方法

应用MSC/NASTRAN有限元分析软件,对螺栓弯曲强度进行了分析,通过与工程计算结果的对比,证明有限元模型和有限元分析方法是准确可靠的。     

俯仰运动矩形贮箱中液体的非线性晃动

首先针对俯仰运动贮箱中液体的晃动提出了变分原理和新一类Lagrange函数，以此为基础可以解析方式来研究俯仰运动贮箱中液体有限幅值晃动。以无挡板开口二维、刚性短形贮箱为例，研究了其中液体的有限幅值晃动。单就液体波动幅值而言，在一定激励频率范围内，理论计算值与实验结果具有很好的一致性。     

Simulated microgravity induce apoptosis and down-regulation of erythropoietin receptor of UT-7/EPO cells

Hematopoietic progenitor cell proliferation can be alternated on either spaceflight or under simulated microgravity experiments on the ground; however, the underlying mechanism remains largely unknown. In the present study, we have demonstrated that exposure of human erythropoietin (EPO)-dependent leukemia cell line UT-7/EPO cells to conditions of simulated microgravity with a rotary culture instrument significantly inhibited the cellular proliferation rate. Adding higher concentrations of EPO to the culture medium failed to improve the inhibitory status. Cell apoptosis was detected by fluorescence staining of cell nuclei and a flow cytometry assay using Annexin V/PI double staining. This microgravity-induced apoptosis in UT-7/EPO cells could be blocked by a pancaspase inhibitor Z-VAD-FMK. Immunoblotting demonstrated that rotary culture resulted in a reduction of the expression of Bcl-xL, an anti-apoptotic protein, and the cleavage of caspase-3. Furthermore, rotary culture reduced surface localization and protein content, as well as the mRNA expression of erythropoietin receptor (EPOR) of UT-7/EPO. Take together, the findings indicated that simulated microgravity may induce mitochondrial related apoptosis of UT-7/EPO cell through depressing the EPO–EPOR pathway.     

大型弹簧电镀锌工艺优化

采用扫描电镜(SEM)研究了发蓝、超声波酸洗前处理工艺对大型弹簧零件表面残余氧化皮的去除效果以及这两种前处理工艺对镀锌层的结合力与抗腐蚀性能的影响。结果表明,采用适当的发蓝、超声波酸洗等前处理工艺,能够有效去除零件表面顽固的残余氧化皮,较大幅度地提高镀锌层与金属基体的结合力,并提高镀锌层的抗腐蚀性能。     

高硬度薄壁筒形件数控车加工工艺

以典型零件加工为例,通过探讨高硬度薄壁零件在数控车床加工中存在的易变形、零件尺寸及表面粗糙度不易保证、断续切削时刀具易破损等技术问题,对加工难点进行分析,给出了工艺路线和加工方案,通过优化、完善夹具设计、加工程序和切削参数,使用新型刀具,并打破硬态切削的一些常规做法,从而有效解决高硬度薄壁类零件的车削加工难题。     

Upregulation of erythropoietin receptor in UT-7/EPO cells inhibits simulated microgravity-induced cell apoptosis

Hematopoietic progenitor cell proliferation can be altered in either spaceflight or under simulated microgravity experiments on the ground, however, the underlying mechanism remains unknown. Our previous study showed that exposure of the human erythropoietin (EPO)-dependent leukemia cell line UT-7/EPO to conditions of simulated microgravity significantly inhibited the cellular proliferation rate and induced cell apoptosis. We postulated that the downregulation of the erythropoietin receptor (EPOR) expression in UT-7/EPO cells under simulated microgravity may be a possible reason for microgravity triggered apoptosis. In this paper, a human EPOR gene was transferred into UT-7/EPO cells and the resulting expression of EPOR on the surface of UT-7/EPO cells increased approximately 61% (p < 0.05) as selected by the antibiotic G418. It was also shown through cytometry assays and morphological observations that microgravity-induced apoptosis markedly decreased in these UT-7/EPO–EPOR cells. Thus, we concluded that upregulation of EPOR in UT-7/EPO cells could inhibit the simulated microgravity-induced cell apoptosis in this EPO dependent cell line.