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1.
引言1980年,Maddox开创性地发现了中尺度对流复合体MCC,此后国内外的学者对MCS进行了大量的研究,揭示了MCS的发生环境和生成条件。Maddox通过对10个MCC个例的合成分析,得到MCC形成区、成熟区及消亡区的环境形势。他认为,MCC倾向于发生在高层(200hPa)宽广的、相对弱的西风急流的反气旋一侧的右出口区,系统初始形成在通常呈东西向的弱的大尺度锋区附近,在对流层中层(700和500hPa)有弱的短波槽在近于纬向的气流中向东移动,  相似文献   

2.
This paper examines the use of remote sensing satellites for verification in public international law. Verification always depends on the specific agreement or mission to be verified. There are no general framework rules: the means of verification and the verifying authorities vary from agreement to agreement and from mission to mission. Rapid technological development and the intensifying international cooperation have led to an increasing number of international verification missions. Whereas, in the past, verification was at the heart of intelligence and national services, the commercialization of the remote sensing industry and the information revolution have supported the creation of joint initiatives in this field. Traditionally, verification is associated with disarmament and arms control treaties, but the paper will underline that this is only one field of application for verification missions. It is important to note that there is no binding international regime specifically addressing such activity. The lack of legal certainty in this field also applies to the use of remotely sensed data as evidence in legal proceedings.  相似文献   

3.
许宏  袁仁学  孙波  战立斌  许艳超 《火箭推进》2015,41(2):87-89,97
提出了一种适合肼类推进剂航空运输的复合加强型推进剂包装容器设计,包装容器采用多层复合结构,满足了高结构强度、轻量化、有效隔热、泄漏应急处理等要求。开展了跌落试验和火焰灼烧试验,结果表明,包装容器可用于少量液体推进剂的包装防护,可有效提高对泄漏、跌落、灼烧等危险因素的防护能力,提高了液体推进剂在贮存和运输过程中的安全性和可靠性,满足危险品航空运输安全要求。  相似文献   

4.
2005年9月26日,中国航天科技集团公司召开了第一次工艺工作会议。会议由张丽辉总经理助理主持,集团公司总经理张庆伟做了重要讲话,许达哲副总经理做了工作报告。张庆伟总经理在讲话中强调:今后的工艺工作要强化“一个意识”,提高“两个能力”,把握“三个结合”,培养“四个能力”,抓好“五项工作”。他明确指出:“工艺是核心竞争力,是重要的生产力”。要完成“十一五”期间的科研生产任务,必须提高关键工艺技术的攻关能力与工艺基础能力。工艺作为制造的核心,工艺水平必须要有一个大的跨越,因此,对于工艺工作,要做好设计和工艺的结合、工艺技术与工艺管理的结合、工艺与信息化的结合。为了更好地学习、宣传、贯彻中国航天科技集团公司第一次工艺工作会议精神,本刊特辟专栏摘要刊登张庆伟总经理、许达哲副总经理的重要讲话。  相似文献   

5.
通用导弹气动力计算软件DATCOM的开发与校验   总被引:5,自引:0,他引:5  
M issile Datcom是由美国空军研发的一套用于导弹气动力估算的软件,在飞行器方案设计阶段具有较高的实用价值。在深入分析M issile Datcom软件源代码的基础上,结合研究成果对软件进行了开发,利用VC 编制了便于用户使用的图形界面,并利用某型导弹的风洞试验数据对软件进行了校验。结果表明,该软件在一定范围内能提供较高精度的气动力系数估算结果,对不同导弹气动力外形具有较强的适用性,为国内气动力工程估算提供了一套通用工具。  相似文献   

6.
A recent study made by ESA has reviewed the scientific investigations to be only, or best, performed on the Moon (Return to the Moon, ESA SP-1150, June 1992), and has identified the need for a manned lunar outpost to provide support to field geologists in sampling and in-situ observations of the lunar surface, and to allow the refurbishments of surface stations and rovers. Planning and development for a manned outpost on the Moon requires an in-depth understanding and analysis of the functions this outpost is expected to perform. We therefore analyzed the impact of the proposed scientific investigations on the design of a manned lunar outpost. The specific questions raised in our study were: What are the medical, physiological and psychological risks for a crew to stay and to work on the Moon? What transit and lunar surface infrastructures (habitats and vehicles) are needed to minimize those risks?  相似文献   

7.
低温非接触式端面密封参数优化与试验验证   总被引:1,自引:0,他引:1  
针对液氧/煤油发动机使用的接触式端面密封存在端面温升大、重复使用性能不理想等问题,首先采用无限长平面平行槽的惠普尔理论构建非接触式端面密封计算模型,然后仿真计算密封结构参数对气膜刚度以及泄漏量等密封性能的影响,最后以最大气膜刚度为优化目标,对非接触端面密封结构参数进行优化设计.低温运转试验验证了优化结果的正确性和非接触式端面密封具有良好的重复使用性.  相似文献   

8.
远征三号上面级轨控发动机研制及在轨验证   总被引:2,自引:0,他引:2  
综述了国内外上面级及其轨控发动机技术发展情况。基于远征三号上面级的任务特点,提出了5 000 N轨控发动机技术方案,着重介绍了5 000 N发动机的地面试验和首次飞行应用情况,总结了远征三号上面级轨控发动机研制经验,供类似火箭发动机研制参考。远征三号上面级5 000 N发动机采用挤压式推进剂供应系统、直流式喷注器、再生冷却方案和复合材料喷管延伸段,具有结构简单、多次启动能力强、双向摇摆角度大等优势,于2018年12月29日进行了首次飞行应用。  相似文献   

9.
在今年的全国空管工作会议上,苏兰根局长再一次阐述了空管系统“三横三纵”体系建设的重要性及“三横三纵”体系建设的目标、原则和思路,并强调指出在当前和今后一段时期,空管系统要牢固树立持续安全理念,以“三横三纵”体系建设为重点,以完善一体化建设为保障,建立符合航空运输发展需求的空中交通管理系统。苏局长关于“三横三纵”体系的论述,是全面落实科学发展观,保证空管持续安全、促进空管系统又好又快发展的重要指导思想,同时也是空管一体化后,在科学分析当前空管事业发展的阶段性特征和形势做出的创新性和前瞻性的战略决策。  相似文献   

10.
Berg HE  Tesch PA 《Acta Astronautica》1998,42(1-8):219-230
We have developed a non-gravity dependent mechanical device, which provides resistance during coupled concentric and eccentric muscle actions, through the inertia of a spinning fly-wheel (Fly-Wheel Ergometry; FWE). Our research shows that lower-limb FWE exercise can produce forces and thus muscular stress comparable to what is typical of advanced resistance training using free weights. FWE also offers greater training stimuli during eccentric relative to concentric muscle actions, as evidenced by force and electromyographic (EMG) measurements. Muscle use of specific muscle groups, as assessed by the exercise-induced contrast shift of magnetic resonance images, is similar during lower-limb FWE and the barbell squat. Unlike free-weight exercise, FWE allows for maximal voluntary effort in each repetition of an exercise bout. Likewise, FWE exercise, not unassisted free-weight exercise, produces eccentric "overload". Collectively, the inherent features of this resistive exercise device and the results of the physiological evaluations we have performed, suggest that resistance exercise using FWE could be used as an effective exercise counter-measure in space. The flywheel principle can be employed to any exercise configuration and designed into a compact device allowing for exercises stressing those muscles and bone structures, which are thought to be most affected by long-duration spaceflight.  相似文献   

11.
网络信息技术的快速发展,为高校思想政治工作提供了新的手段,极大地拓展了思想政治工作的空间和渠道。思想政治教育工作者有必要深入研究学生思想活动的新情况、新特点,充分发挥网络信息技术的优势,创新思想政治工作的方法、形式和手段,进而完善高校思想政治工作体制。  相似文献   

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