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851.
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853.
U.M. Leloglu E. Kocaoglan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
Although it is generally agreed that the outer space should be used for the benefit of all mankind, only a fraction of the countries have the necessary technological base for accessing space. Space technology, with its implications on science, economy and well-being of citizens, is mostly chosen as one of the priority areas for technological development by developing countries. However, there is already an over-capacity in global space industry and there are doubts on necessity of additional capacity establishment by developing countries. In this study, the importance and benefits of capacity-building in these countries are emphasized and the advantages and disadvantages that developing countries have in the framework of space technology acquisition are briefly presented. The feasibility of certain levels of space technology is discussed and the necessity of combining existing indigenous capabilities with technology obtained from foreign sources in the optimal way is stressed. We have also mentioned various general mechanisms of technology transfer and argued the importance of licensing in catching-up developed countries. After considering the necessary conditions of efficiency of technology, such as establishment of regional centers of space science and technology education by United Nations, joint development of space systems, complete technology transfer packages, cooperative space projects within regional organizations, coordinated constellations and special agreements with large space agencies, which are specific mechanisms already in use, are reviewed. Some typical examples of mechanisms are also given with special emphasize on small satellite technology that makes access to space affordable for many countries. Through sharing and analyzing the experience of developing countries in their odyssey of space capacity-building, the difficulties can be negotiated and the vicious circles can be broken. This study, in our view, is a step to incite a general discussion of obstacles and opportunities for developing countries, that could help them in using their limited resources effectively, hence, enable them to offer better conditions to their citizens and to contribute space science to a larger extend. 相似文献
854.
本文论述了计算机辅助工业设计(CAID)的基本内涵,技术研究现状及其发展趋势,阐明了CAID将使工业设计朝着多元化、优化、一体化的方向发展,使人机交互方式更加自然,创新设计的手段更为先进,有效。 相似文献
855.
Oleg Polovnikov 《Aerospace Science and Technology》2000,4(8):567
At present, various radio navigation systems are employed during the automated approach of a transport vehicle to a space station. Experience has shown that emergency situations can occur in which it is necessary to revert to manual override of the automatic approach.Such situations have indeed occurred during flight operations of the space station Mir. The crews of the transport vehicles and the Mir used manual steering more than 30 times for successful docking, and four times for approach to the station.Successful manual steering demands absolute understanding of the relative orbit parameters. The decisive task of the crew is to determine these relative parameters. This is possible using visual observations from either the transport vehicle or the station using simple and reliable instruments. This article explains the algorithm for determining the relative orbits from visual crew observations, based on similarities of relative orbit families. 相似文献
856.
赵榕 《沈阳航空工业学院学报》2008,25(6)
介绍了辽宁省产业结构调整的基本情况,分析了辽宁省弱势群体的总体形势及辽宁省产业结构调整对弱势群体就业问题的影响,探讨如何通过合理的产业布局缓解弱势群体就业的严峻形势,从而提出在辽宁产业结构调整中扩大弱势群体就业规模的有效措施。 相似文献
857.
The convection of heat-generating fluid in a rotating horizontal cylinder is experimentally investigated. The threshold of convection excitation, the structure of convective flows and the heat transfer in the cylinder depending on the heat release capacity, liquid viscosity and aspect ratio of the cavity are studied. It is found that the average convection is excited by the thermovibrational mechanism —the gravity force, rotating in the cavity frame, produces the oscillations of non-isothermal fluid relative to the wall, which in turn result in excitation of mean convective flows. It is shown that the structure of convective flows depends on the dimensionless velocity of rotation. At relatively low rotation velocity the convection develops in the form of a periodic system of vortices regularly distributed along the cylinder axis. The threshold of excitation (critical value of vibration parameter) of three-dimensional vortex structures grows with rotation velocity. Above some definite rotation velocity the convection develops as two-dimensional rolls parallel to the axis of rotation. The threshold of two-dimensional structures excitation does not depend on the rotation velocity. Besides the structure of thermal convective flows the analysis of the relatively weak currents generated by the inertial waves below the threshold of convection is performed. 相似文献
858.
路丹 《郑州航空工业管理学院学报(管理科学版)》1993,(4)
在社会主义市场经济条件下,如何搞活大中型国有军工企业成为当前困扰军工企业的最重要的问题。增强营销意识,迎接市场挑战是我厂经历种种曲折后得出的珍贵经验,紧紧围绕市场需求,搞好支柱产品开发和市场开发,调整营销思路,制定营销策略已成为企业当务之急,因此,作者从管理体制、运行机制、无形资产、人员培训等方面提出改善现有营销状况的对策。 相似文献
859.
简要概述了光学采样成像系统组成及调制传递函数补偿(MTFC)概念;采用计算机仿真的方法模拟成像链路,MTFC是成像链路的一个重要环节,通过改变成像链路中的参数,研究链路中的混叠、光学遥感器噪声、量化、有损压缩对MTFC的影响。 相似文献
860.
离心式压气机耦合松弛多学科设计优化方法 总被引:1,自引:1,他引:0
为提高多学科设计优化的寻优效率,以离心式压气机为对象,开展了耦合松弛多学科设计优化方法的研究.针对松散耦合方法建立的离心式压气机的流-热-固耦合分析模型,为了避免反复迭代导致的分析、优化时间过长,构建了分层次的离心式压气机耦合松弛优化设计系统.在气动优化中采用全局寻优算法探索系统最优气动设计方案;在耦合优化阶段,综合考虑学科间耦合及相互作用,在气动优化的基础上局部寻优校验气动优化结果并得到最终设计方案.这种不同复杂层次模型的优化设计有效缩减了系统优化设计周期. 相似文献