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1.
固体火箭冲压发动机的若干技术问题 总被引:2,自引:0,他引:2
简述了固体火箭冲压发动机类型及工作原理,总体评价了固体火箭冲压发动机发展时快时慢的原因,弹-机一体化设计、贫氧推进剂、进气道、转级机构、补燃室等设计中应注意的问题,提出了应加强的研究工作,即开展高能低沉积燃烧产物贫氧推进剂研究;完善多种燃气流量调节装置方案,提高其可靠性;进一步开展一次燃烧和二次掺混燃烧的理论和实验研究,提高燃烧效率;尽快建立自由射流等试验研究手段,开展相关的研究工作;适时开展固体燃料冲压、固体超燃冲压及膏体冲压等发动机的研究,不断拓宽应用领域。 相似文献
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美军重点发展的小型精确制导武器 总被引:4,自引:0,他引:4
在近四次主要局部战争中,美军依靠大量使用精确制导武器,取得了良好的作战效果。在四次战争中美军所使用的精确制导武器数量所占比例分别为:1991年海湾战争7.6%;1999年科索沃战争35%;2001年阿富汗战争60%;2003年伊拉克战争68.3%。由此可以看出,精确制导武器的使用比例逐渐上升, 相似文献
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举目环顾,航天界17位两院院士、许多重量级的权威专家难得地聚首一堂。这些中国航天科技领域的顶级大师坐到一起原来是在办一件将对中国航天事业产生重大影响的大事——为中国的运载火箭升级换代筹划把关。这是记者3月16日在新一代运载火箭基本型总体方案论证报告评审会上看到的情景。 相似文献
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Ryojiro Akiba Fwu-Ren Liann Hiroki Matsuo Kuninori Uesugi Mitsuru Ichikawa 《Acta Astronautica》1980,7(6):797-805
Missions to Halley's comet in 1985–1986 are discussed. They include pre-perihelion encounter, post-perihelion encounter, the utilization of Venus swing-by, one round mission in which the spacecraft goes the round of the Sun before the encounter and missions to the point beneath the perihelion of Halley's orbit. Technological feasibility of the small spacecraft is also discussed on the basis of the use of the improved version of M-3S launch vehicle. 相似文献
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火星探险是21世纪最重要的太空挑战任务,火星也是最具魅力的星球。物理学家霍金曾经说过:除非我们移民太空,否则,我不认为人类在1000年后还能幸存,因为会有太多意外事故降临到栖身于这颗行星的生命身上。不过我是个乐天派,我相信人类会走出去,找到适合居住的其他世界。火星,这个红色星球,就 相似文献
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从机理上对浮游精炼法进行了理论分析,认为增加熔剂量可以提高除气效果,但过量的熔剂又可能会给铝液带来二次反应夹杂;[H]含量达到平衡浓度前,增加除气时间可以提高除气效果;随着静置时间的延长,[H]含量有一个先减少后增大的趋势。采用旋转吹气一熔剂法净化铝液,以净化后铝液的[H]含量为考察目标,按照均匀理论设计了净化参数的多因子实验。对实验结果进行逐步回归和线性回归分析,确定了旋转吹气一熔剂法工艺规范:精炼剂加入量0.2%;除气时间10min;静置时间15min。 相似文献
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With the vast experience gained by Aerospace Community in the last five decades, the natural future course of action will be to expand Space Exploration. Our understanding of Moon is relatively better with a number of unmanned satellite missions carried out by the leading Space Agencies and manned missions to Moon by USA. Also a number of unmanned satellite missions and surface rover missions were carried out to Mars by those Space agencies generating many new details about Mars. While the future exploration efforts by global community will also be centered obviously on Moon and Mars, it is noteworthy that already NASA had declared its plans for establishing a Surface Base on Moon and developing the technical infrastructure required. Surface Bases on Moon and Mars give rise to a number of strategic, technical and ethical issues both in the process of development, and in the process of establishing the bases. The strategic issues related to Moon and Mars Surface Bases will be centered around development of enabling technologies, cost of the missions, and international cooperation. The obvious path for tackling both the technological development and cost issues will be through innovative and new means of international cooperation. International cooperation can take many forms like—all capable players joining a leader, or sharing of tasks at system level, or all players having their independent programmes with agreed common interfaces of the items being taken to and left on the surface of Moon/Mars. Each model has its own unique features. Among the technical issues, the first one is that of the Mission Objectives—why Surface Bases have to be developed and what will be the activity of crew on Surface Bases? Surface Bases have to meet mainly the issues on long term survivability of humans on the Mars/Moon with their specific atmosphere, gravity and surface characteristics. Moon offers excellent advantages for astronomy while posing difficulties with respect to solar power utilization and extreme temperature variations. Hence the technical challenges depend on a number of factors starting from mission requirements. Obviously the most important technical challenge to be addressed will be in the areas of crew safety, crew survivability, adequate provision to overcome contingencies, and in-situ resource utilization. Towards this, new innovations will be developed in areas such as specialized space suits, rovers, power and communication systems, and ascent and descent modules. The biggest ethical issue is whether humankind from Earth is targeting ‘habitation’ or ‘colonization’ of Moon/Mars. The next question will be whether the in-situ resource exploitation will be only for carrying out further missions to other planets from Moon/Mars or for utilization on Earth. The third ethical issue will be the long term impact of pollution on Moon/Mars due to technologies employed for power generation and other logistics on Surfaces. The paper elaborates the views of the authors on the strategic, technical and ethical aspects of establishing Surface Bases and colonies on Moon and Mars. The underlying assumptions and gray areas under each aspect will be explained with the resulting long-term implications. 相似文献
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Lighter-than-air vehicles are being studied and developed as solutions to problems in transportation and in communications and service. These vehicles include balloons, balloon-airship systems and airships. Tethered balloons of streamline form have been developed for both military (surveillance) and civil (telecommunications) applications. These are capable of flying at 4600 m altitude in 100 km/hr winds and supporting payloads up to 1678 kg. Other applications include use of natural shaped balloons for logging in forested areas and for transport of cargo from ship-to-shore. Free balloons have been flown up to 51, 812 m and 7624 kg have been carried to 34,440 m. Balloon-like remotely piloted airships are being studied and developed as high altitude geo-stationary platforms for telecommunication and surveillance. Many new and lower cost benefits would result from the successful development of this type. The carrying of heavy large-volume cargoes promises to be an important and unique application for airships which are designed to achieve precise hovering while being loaded or unloaded. Several types are being studied for this purpose. Other new applications include use of airships for airport feeder passenger transport, and as large long endurance naval patrol vehicles. Technology programs must be developed which will enable new airships to be designed and built. These would include studies in aerodynamics, materials, structures, propulsion, and operational techniques. The advancement of these new concepts is handicapped by the lack of an established industry, confidence, and the complexity and cost of development. Yet where success has been achieved, it has been worth the risk. Government support is required to achieve these goals. 相似文献
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朱明贤 《华北航天工业学院学报》2005,15(4):29-31
以人为本思想内涵丰富,以人民为本是以人为本的种概念;“人”和“人民”各有其特定的涵义;在内涵上,“人”要比“人民”更丰富,在外延上,“人”要比“人民”宽泛得多;在中国现阶段,就落实以人为本来看,也有其特定的要求和针对性。因此,人为本中不能解读为以人民为本。 相似文献
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互联网搜索巨头谷歌公司9月14日表示将同X奖基金会合作举办一项挑战赛,并向把机器人送到月球人漫游并发回高分辨率图像资料和数据的公司提供3000万美元的奖金。该公司已在其网站上设立了“谷歌月球”(Google Moon)网页,上面有麻脸般的月球表面的图像。这些图像由以往探月任务拍摄的照片加工而成,包括1969年阿波罗11号登月时拍摄的照片。 相似文献
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朱明贤 《北华航天工业学院学报》2005,15(4):29-31
以人为本思想内涵丰富,以人民为本是以人为本的种概念;"人"和"人民"各有其特定的涵义;在内涵上,"人"要比"人民"更丰富,在外延上,"人"要比"人民"宽泛得多;在中国现阶段,就落实以人为本来看,也有其特定的要求和针对性.因此,人为本中不能解读为以人民为本. 相似文献
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On board the orbital complex “Salyut-6-Soyuz” during long-term near 0-gravity space flight the technological experiments on synthesis of the superconducting MoGa5, MO3Ga and Nb3Sn intermetallic compounds by means of liquid-phase diffusion and on bulk crystallization of the hypoeutectic superconducting Pb-Sn alloy and magnetically ordered Gd3Co and (Gd0.2Tb0.8)3Co compounds have been performed. During the process of the liquid-phase diffusion considerable changes of the formation of the reaction layers (mechanisms, phase composition, thickness, etc.) in the superconducting Mo-Ga and Nb-Sn systems were observed. MoGa5, Nb6Sn5 and NbSn2 phases were found in the ground-based samples while in the flight samples the formation of MoGa5, Mo3Ga, Nb3Sn and Nb6Sn5 phases was observed. As a result of the changes of the phase composition of the diffusion layers in the flight samples two superconducting transitions at 18.3 and 5.7 K were established (only one transition at 6.9K was measured for the ground-based sample) (Savitsky et al., Izv. Akad. Nauk SSSR, Metals5, 224–232, 1982; Zemskov et al., Izv. Akad. Nauk SSSR, Physics49, 673–680, 1985). Considerable increasing of the critical current measured for the Pb-Sn flight sample has been observed (Savitsky et al., Dokl. Akad. Nauk SSSR257, 102–104, 1981; Zemskov et al., 1985). Better homogeneity and crystal structure perfection of the flight Gd3Co and (Gd0.2Tb0.8)3Co samples have been established by means of the micro-zonde and low-temperature X-ray technique (Savitsky et al., Acta Astronautica11, 691–696, 1984; Zemskov et al., 1985). Different behaviour of the ground-based and flight samples in the process of magnetization and the displacements of the temperatures of the magnetic phase transitions have been observed. 相似文献
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简介了工艺文件更改的控制方法,讨论了工艺文件更改单的签署、填写以及电子文档的管理等问题,并对其具体内容作了阐述。 相似文献
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7月9日,中南地区空管体制改革大会胜利召开,拉开了民航空管体制改革的帷幕,中南地区空管局率先完成了一体化改革。随着改革的不断深化,中南空管将步入新一轮发展期,面对新的管理体制和运行模式,中南空管局党委一班人 相似文献