面向问题域的需求工程应用

文章阐述了需求工程与问题域的相关概念及内在联系,分析了上下文图描述问题与问题域的不足,及面向问题域分析方法的必要性,讨论了如何用问题图的形式描述问题及其问题域,从而明确、详细地反映出需求是如何被满足的.     

钛合金螺钉加工制造研究

从钛合金螺钉加工中几个卡脖子的氢脆问题、润滑问题、裂纹问题和热处理问题出发,研究钛合金螺钉的主要加工问题的解决办法,并对其原理和方法作了介绍.     

质量问题归零中应把握的几点工作

质量问题归零是装备研制生产中的一项重要内容,正确认识和科学地对待质量问题,是确保质量问题归零的前提。把好质量问题归零的标准,利用质量问题归零的财富,对做好质量工作具有启示和借鉴作用。     

后形而上学时代伦理规范的“基础”问题——对问题与概念的分析和澄清

伦理规范的"基础"这一问题,是伦理学最为根基性的问题。当代科学与后形而上学时代特征决定着这一基础问题思考和研究的背景理论框架与核心理念,同时,对"基础"问题的理解和要求也决定着这一根本问题的方向和视域。因而,对于"后形而上学"与"基础"这两大问题的分析和澄清,是伦理规范基础问题研究的逻辑起点和必要前提。     

对台阶问题与一类不定方程问题的探讨

文献[1]研究台阶问题时提出了它的两个等价命题,笔者论证了其中的不定方程问题与台阶问题是不等价的,对一般台阶问题和这一类不定方程作了深入讨论,并彻底解决了这两类问题。     

所有权保留若干问题研究

论文研究了我国现行法律制度下,所有权保留成立要件问题,所有权保留的效力问题,所有权保留买卖中标的物的风险转移问题,同一标的物上所有权保留与其他担保方式的权利顺位的确定问题。     

关于“质量问题归零”前移的探讨

结合QQJA10-2002《航天产品质量问题归零实施要求》,探讨了航天产品质量问题归零工作前移的路子,阐述了质量问题归零工作前移的目的、意义、可行性、实施方式和效果评价,并对开展质量问题归零工作前移的相关要求、实施可能遇到的问题及对策进行了分析和说明。     

型号共性质量问题识别与治理机制探讨

共性质量问题具有关联度大、影响范围广、影响程度深等特点,历年来一直是航天科技集团公司各级单位质量工作的重点。但目前各单位对共性质量问题的认识还不统一,普遍存在共性问题识别不全面、对其深层次的原因分析不充分、治理效果不明显等问题。本文在对集团公司共性质量问题治理工作的现状进行总结的基础上,进一步明确了共性质量问题的范畴和分类,并对型号共性质量问题的识别和治理机制进行了初步的探讨和研究,提出了面向集团公司、院、厂(所)三级的针对共性质量问题识别与治理工作的相关建议,以期提高集团公司各单位共性质量问题识别和治理工作的水平。     

一种卫星成像调度的约束修正方法

约束修正是卫星成像调度的重要组成部分,负责处理成像调度方案的约束满足与优化的问题.为得到优化可行的成像调度方案,针对一类带有卫星存储器和数据下传等约束的卫星成像调度问题,提出一种新的约束修正方法.首先构建时间序有向图模型,将约束修正问题归结为点带约束成本的路径搜索问题,针对该模型提出一种基于标记更新的约束修正算法.通过针对实际问题的实验分析,表明该方法能够在规定的时间内求得问题的最优解,有效的解决了卫星成像调度的约束满足与优化问题.     

空间对接动力学半物理仿真基本问题及解决方案研究

分析了空间对接半物理(HIL,Hardware-In-the-loop)仿真系统设计难点,将空间对接半物理仿真设计问题归纳为四个基本问题,即稳定性问题、动态复现精度问题、滞后补偿器的鲁棒性问题以及适应性问题。为了解决上述问题,作者阐述了空间对接半物理仿真系统设计思想,旨在空间对接频带范围内,消除或减弱仿真硬件接口对半物理仿真系统的影响。在此基础上,确立了力和力矩传感器及其滤波器设计准则、数字控制采样频率的选取依据和运动模拟器的设计方案等。最后文章探讨了空间对接半物理仿真系统动态特性的验证方法。     

燃气发生器喷注器内氧腔三维流动分析

采用计算流体力学方法数值模拟了某型液体火箭发动机燃气发生器氧腔内部流动,详细分析了氧腔内部的三维流动特性。从压力分布等方面分析了造成喷嘴流量分布不均匀的原因,并据此对发生器结构进行了改进,结果表明喷嘴流量分配均匀性得到了明显改善。     

Ariane transfer vehicle in service of man in orbit

The Ariane transfer vehicle (ATV), an Ariane 5 borne, unmanned propulsion vehicle, is designed to transport the logistics needed to resupply the International Space Station (ISS) and the man tended free flyer (MTFF) step 2 with pressurized and unpressurized cargo and to dispose the waste. The ATV is an expendable vehicle and is disposed of by a safe atmospheric burn up. In accordance with the AR5 schedule it should be operational in 1996 for missions toward ISS and beyond the year 2000 for MTFF 2 missions. The main constituents of the proposed ATV are the modified AR5 third stage L5, an upgraded VEB steering the launcher as well as the ATV and the P/L-adaptor providing mechanical and umbilical links to the payload. The mechanical part of the RVD-kit will be placed on the payload-module, the main RVD sensors are located on the adaptor and the needed computer intelligence will be integrated on the VEB. To minimize the development, and recurring costs, the ATV concept fully complies to the idea of maximum use of existing hardware and software, mainly from the AR5, Hermes and Columbus programs thus minimizing development and recurring costs. The ATV is compatible to ISS, MTFF and OMV and is able to transport logistic modules compatible with NSTS and U.S.-expendable launchers.     

Entrapment of bacteria in fluid inclusions in laboratory-grown halite

Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins.     

Inflection points in the development of energy in space

Basing his comments around a report on the Space Power Systems 1997 conference, ‘Energy and Space for Humanity’, held in Montreal, 24-28 August 1997, Richard Boudreault describes the progress made in getting the concept of power from space accepted by the terrestrial utilities. Increasing worries about the sustainability of current power sources together with deregulation of power distribution make space power more attractive. However, the high cost of access to space is a barrier, though this is starting to fall.     

Power law distribution in statistics of failures in operation of spacecraft onboard equipment

The possibility of using the statistics of recurrence time for extreme events is studied in this paper having in mind the problems of control and prediction of failures in spacecraft operation. The information about failures onboard satellites of various types presented by the US National Geophysical Data Center was analyzed. It was found that the probability density of recurrence intervals followed a power law of the Pareto type with an index equal to 2.3. The obtained result is consistent both with the theory of normal catastrophes and with the principle of self-organization of criticality for metastable active heterogeneous environment. A practical consequence of the obtained result consists in the fact that predictions of these extreme events should not rely on traditional models with the second-order Pearson statistics. To make predictions, the models are necessary that take into account the power law distribution of recurrence intervals for failures on satellites. The failures should be considered in these models as extreme events connected with manifestation of the space environment factors.     

航空航天复合材料非热压罐成型研究进展

介绍了复合材料非热压罐成型的研究进展,包括非热罐成型用的树脂体系、预浸料技术、纤维自动铺放技术以及双真空袋成型工艺等,探讨了非热压罐技术的发展现状和前景。     

航天科技集团公司2006年工作要点

中国航天科技集团公司党组一号文件部署了集团公司2006年九个方面的工作要点。现将这九个要点归纳为四大板块,同时将每个要点的详细内容逐一呈现,以便读者学习、领会与掌握。     

Achievements of CASC in 2016

<正>2016 was an important year for China’s space industry.October 8,2016 marked the 60th anniversary of the creation of the nation’s space industry.Through 60 years’unremitting effort of generations of space personnel,China’s space industry develops and grows stronger and has achieved splendid results representing by"two bombs and one satellite",manned spaceflight and lunar exploration,which greatly enhanced the national strengths in defense,economy,science and technology     

VFW技术在发动机试验系统多余物检测中的应用

论述了发动机试验工艺系统多余物产生机理、多余物控制的基本要求,提出了一种基于VFW技术建立的便携式简易内窥镜多余物图像检测系统.主要对软件设计思路进行了论述,并详细介绍了该系统在现有试车台工艺系统多余物控制中的应用,该技术的应用实现了多余检测过程的数字化管理,提高了试验系统单元部件多余物检测效率.并使检测手段便捷化.