航空电子设备NSEE试验评价方法

本文定义了航空电子设备大气中子单粒子效应(NSEE)硬失效、硬错误与软错误等大气中子辐射可靠性表征参数,提出了一套航空电子设备抗大气中子单粒子效应危害能力的试验评价方法,包括试验应力终止条件与起始条件的确定方法、M_NSEE预估方法、试验程序、试验评价方法等,并通过某航空用卫星导航接收机试验案例证明了该方法在工程应用中的可操作性与有效性,通过掌握数字信号处理(DSP)、静态随机存储器(SRAM)、现场可编程门阵列(FPGA)的NSEE敏感特性,可为航空用卫星导航接收机NSEE危害防控提供针对性的技术支持.本文为我国航空电子产品大气中子单粒子效应试验评价奠定了理论与应用基础,同时也为其他电子信息产品在大气中子单粒子效应试验评价方面提供了重要依据和参考.      

Using the radial basis function neural network to predict ionospheric critical frequency of F2 layer over Wuhan

Neural networks (NNs) have been applied to ionospheric predictions recently. This paper uses radial basis function neural network (RBF-NN) to forecast hourly values of the ionospheric F₂ layer critical frequency(f_oF₂), over Wuhan (30.5N, 114.3E), China. The false nearest neighbor method is used to determine the embedding dimension, and the principal component analysis (PCA) is used to reduce noise and dimension. The whole study is based on a sample of about 26,000 observations of f_oF₂ with 1-h time resolution, derived during the period from January 1981 to December 1983. The performance of RBF-NN is estimated by calculating the normalized root-mean-squared (NRMSE) error, and its results show that short-term predictions of f_oF₂ are improved.     

Survival and death of the haloarchaeon Natronorubrum strain HG-1 in a simulated martian environment

Halophilic archaea are of interest to astrobiology due to their survival capabilities in desiccated and high salt environments. The detection of remnants of salty pools on Mars stimulated investigations into the response of haloarchaea to martian conditions. Natronorubrum sp. strain HG-1 is an extremely halophilic archaeon with unusual metabolic pathways, growing on acetate and stimulated by tetrathionate. We exposed Natronorubrum strain HG-1 to ultraviolet (UV) radiation, similar to levels currently prevalent on Mars. In addition, the effects of low temperature (4, −20, and −80 °C), desiccation, and exposure to a Mars soil analogue from the Atacama desert on the viability of Natronorubrum strain HG-1 cultures were investigated. The results show that Natronorubrum strain HG-1 cannot survive for more than several hours when exposed to UV radiation equivalent to that at the martian equator. Even when protected from UV radiation, viability is impaired by a combination of desiccation and low temperature. Desiccating Natronorubrum strain HG-1 cells when mixed with a Mars soil analogue impaired growth of the culture to below the detection limit. Overall, we conclude that Natronorubrum strain HG-1 cannot survive the environment currently present on Mars. Since other halophilic microorganisms were reported to survive simulated martian conditions, our results imply that survival capabilities are not necessarily shared between phylogenetically related species.     

纳米Co粉在NC基高分子体系中的分散性

为了提高纳米Co粉在含能粘合剂中的分散均匀性,并改善改性双基推进剂的综合性能,对纳米Co粉在以硝化棉(NC)为粘合剂的改性双基推进剂中的分散方法进行了研究。先将化学法制备的纳米Co粉通过超声波分散方法预分散到乙醇和乙酸乙酯的混合溶剂中,然后采用微胶囊分散工艺将2.0%～3.0%的纳米Co粉分散到以NC为粘合剂的双基推进剂基体中,得到粒径为5～15μm的球形颗粒。用光学显微镜和TEM研究了纳米Co粉在推进剂基体中的分散状态。研究表明,先采用超声波将Co粉预分散到有机溶剂中,再采用微胶囊工艺可将Co粉完全分散到以NC为粘合剂的双基推进剂基体中。     

空间实验室大面积太阳电池阵技术研究

介绍了空间实验室大面积太阳电池阵的方案构型，并进行了模态分析、热结构耦合分析和动力学仿真分析。生产出了全尺寸的集成演示样机，进行了展开试验、主展开机构的模态试验，以及半刚性太阳电池板和二自由度驱动机构的振动试验。计算和试验结果表明，技术方案是可行的。     

柔性多体撞击系统的精细H∞控制研究

本文在柔性多体撞击系统动力学方程的基础上 ,将撞击看成是一种扰动 ,设计了一个稳定的控制器以使撞击扰动对控制输出的影响达到最小的目的 ,在分析过程中采用 H∞ 控制原理对该问题进行了研究。在计算中 ,将精细积分法应用于状态动力学方程和 Riccati方程的求解中 ,使计算精度得到大幅度提高。最后通过数值例题说明了本文方法的有效性     

气动计算软件集成系统中的远程控制

随着我国航空航天技术的飞速发展,气动计算软件集成技术日趋成熟,但用户在并行计算中需要手动输入的操作较多。鉴于此,通过编程开发了基于TCP／IP协议的FTP客户端应用程序,实现了对网格文件的信息采集、过滤并将其和参数、脚本文件等批量自动上传的功能。根据批处理文件中的命令,调用Windows平台自带的客户端Telnet,向远程集群管理节点发出命令,远程启动服务器集群的并行计算任务。最后,在客户端实现了远程控制服务器集群上的计算流体力学软件Fluent进行并行计算。结果表明：使用该远程控制系统能够减少用户输入操作,提高计算效率,保证数据的实时更新。     

Numerical study of intrachamber processes dynamics at nozzleless solid propellant rocket engine actuation

The results of the comprehensive numerical analysis for dynamics of intrachamber processes that appear at nozzleless solid propellant rocket engine (SPRE) actuation are presented. A complete cycle of rocket engine operation is analyzed. We solve a conjugate problem involving the igniter actuation; heating, ignition and following combustion of a solid propellant charge; a combustion product flow in the combustion chamber; depressurization of the combustion chamber, and the subsequent motion of the rocket engine blank; variation of the combustion surface geometry at the expense of the gradual and nonuniform burnout of solid propellant web.     

基于CCSDS MO服务参考模型公共服务接口设计

为提高飞行器任务运控系统的可重用性和可扩展性,对基于CCSDS(空间数据系统咨询委员会)MO(任务运营)服务参考模型的系统设计和实现方法进行了研究。针对MO服务参考模型的核心服务层,以我国飞行器任务运控系统的需求为出发点,在分析了MO服务参考框架、MO服务定义、运控功能服务定义和公共服务组成的基础上,对MO各公共服务的接口进行了分析与设计。采用面向对象方法学、设计模式等理念,设计并实现了相关公共服务接口。通过向运控功能服务提供API(应用程序接口),可以支持系统应用层开发。这为建立符合CCSDS MO服务参考模型的飞行器任务运控系统,并实现系统的可扩展性和可重用性提供了支持。