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11.
石墨渗铜喉衬的烧蚀特性   总被引:7,自引:0,他引:7  
介绍了石墨渗铜材料作为固体火箭发动机(SRM)喉衬与.长尾管衬套的烧蚀特性和机理。液态铜在高温高压燃气的作用下仍滞留在石墨基材内,起到抑制烧蚀的效果,改善了KS-8高强石墨的耐烧蚀性能。  相似文献   
12.
基于六自由度模型的弹载计算机闭环仿真系统研究   总被引:1,自引:0,他引:1  
提出了基于导弹六自由度模型,将弹载计算机置于导弹闭环仿真回路,从而构成对弹载计算机进行考核的半实物仿真方法。通过建立导弹六自由度模型,在分析弹载计算机信号接口和软件特点的基础上,对弹载计算机闭环仿真系统的硬件组成和工作原理进行了论述。通过采用高性能的仿真计算机、实时积分算法、智能化接口设备和基于PCI总线的数据通讯方式几个方面,保证了半实物仿真的实时性。  相似文献   
13.
石墨渗铜喉衬材料的微观结构与抗热震性能   总被引:4,自引:1,他引:4  
采用粗粒级高强石墨加压渗铜工艺,制备了石墨渗铜(CIG:copper-impregnated graphite)喉衬材料。对其微观结构与抗热震性能的关系进行了研究。结果表明,由于渗铜提高了原石墨的热导率及整体增韧的综合效果,使石墨渗铜材料比通用的5种石墨材料具有更好的抗热震性能,更好地适应了小型高性能战术导弹、航天飞行器高压强大流量SRM对喉衬材料的要求。  相似文献   
14.
The requirements of systematic exploration of the outer solar system have been intensively studied by a Science Advisory Group (SAG) of consulting scientists for the National Aeronautics and Space Administration (NASA). Comets and Asteroids were excluded from this study, as a separate group is planning missions to these bodies. This paper and accompanying articles on specific related scientific subjects written by members of the SAG, summarize the findings and recommendations of this group. These recommendations should not be interpreted as official NASA policy. Following some general introductory remarks, a brief sketch is given of the development and current status of scientific missions to the inner planets by the U.S. and the U.S.S.R. With this perspective, the development of the U.S. program for investigation of the outer solar system is described. The scientific focus of outer solar system exploration has been studied in detail. The relationship of the outer planetary bodies to one another and to the inner planets, as parts in a unified solar system evolved from a primitive solar nebula, is emphasized. Deductions from outer solar system investigations regarding the conditions of the solar nebula at the time of planetary formation have been considered. Investigations have been proposed that are relevant to studies of the atmospheric structure and dynamics, internal structure of the planets, satellite composition and morphology, and planetary and interplanetary fields and energetic particles. The mission type and sequence required to conduct a systematic exploration of the outer solar system has been developed. Technological rationales for the suggested missions are discussed in general terms. The existing NASA program for outer solar system exploration is comprised of four missions:
  1. Pioneer 10 fly-by mission to Jupiter and beyond, currently underway, with launch on 3 March 1972;
  2. Pioneer G, intended for a similar mission with planned launch 2–22 April 1973; and
  3. Two Mariner Jupiter/Saturn fly-bys in 1977, with experiment selection scheduled for late 1972 and detailed engineering design during 1972–74.
The Science Advisory Group advocates that detailed mission planning be undertaken on the following additional missions for launches during the late 1970's and early 1980's. Together with existing plans, these would provide a balanced, effective exploration program.
  1. 1976 Pioneer Jupiter/Out-of-Ecliptic (One Mission)
  2. 1979 Mariner Jupiter/Uranus Fly-bys (Two Missions)
  3. 1979 Pioneer Entry Probe to Saturn 1980 Pioneer Entry Probe to Uranus via Saturn Fly-by (Three Missions)
  4. 1981/1982 Mariner Jupiter Orbiter (Two Missions).
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本文总结了9项有关ISO9000认证的研究,主要论述了这套国际标准为实施者所带来之利益。这9项研究分别在英国、新西兰、澳大利亚、中国香港特区、美国、巴西、加拿大、法国、德国、日本、韩国、瑞典和荷兰等地进行。研究发现,ISO9000的主要优点有:令运作方式系统化、减少损耗、增加效率和减少顾客投诉。取得ISO9000认证的公司,大多采取较严格的方法去控制分供方。不少取得证书的公司还表示,他们会进一步采用其他的质量管理方法,例如全面优质管理,ISO9000,ISO14000和优质奖的规格。  相似文献   
18.
哥本哈根位于波罗的海和北海之间的厄勒海峡西岸,集聚着充满童话气质的古堡与皇宫、乡村与庄园。不论是沉淀了古老历史的还是延续着皇族传奇的各类建筑,都鳞次栉比地坐落在这里。哥本哈根融合了古典与现代的艺术气息,阿肯艺术中心、路易斯安娜博物馆、国家博物馆、丹麦国家美术馆等众多艺术博物馆各领风骚。富有皇族气质的哥本哈根,贯穿着全年度的各种主题节庆,令狂欢从夏季一直延续到冬季。最著名的莫过于哥本哈根国际爵士音乐节,在每年7月将持续整整10天,着实是不容错过的年度盛会!  相似文献   
19.
Observations of the Galactic center region with the H.E.S.S. telescopes have established the existence of a steady, extended source of gamma-ray emission coinciding with the position of the super massive black hole Sgr A*. This is a remarkable finding given the expected presence of dense self-annihilating Dark Matter in the Galactic center region. The self-annihilation process is giving rise to gamma-ray production through hadronization including the production of neutral pions which decay into gamma-rays but also through (loop-suppressed) annihilation into final states of almost mono-energetic photons. We study the observed gamma-ray signal (spectrum and shape) from the Galactic center in the context of Dark Matter annihilation and indicate the prospects for further indirect Dark Matter searches with H.E.S.S.  相似文献   
20.
高校图书馆向社会服务的探索   总被引:3,自引:0,他引:3  
本文就高校图书馆在市场经济体制下向社会服务的重要性、可能性、服务的途径和方式进行了探讨。  相似文献   
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