首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
After introducing a mathematical definition of the tail-like equilibrium and the dipole-like equilibrium in the magnetosphere, it is shown by using physical intuition based on the Energy Principle that the incompressible assumption for the ballooning instability is more valid for the tail-like configuration when the unstable ballooning mode is strongly localized near the equator. Therefore, before the substorm onset, the near-Earth plasma sheet becomes more tail-like and more likely to be subject to the ballooning instability without the stabilizing influence of the compressibility, when the critical plasma due to the stabilizing tension force is exceeded. The onset of the ballooning instability in the near-Earth plasma sheet seems promisingly relevant to the substorm onset phenomena. Also, the effect of the stochastic plasma dynamics on the ballooning and interchange instabilities is clearly shown.  相似文献   

2.
介绍江西国防科技工业单位的三级计量技术机构进行国防计量认可复查的情况 ,指出了存在的问题 ,并对问题的解决提出了建议  相似文献   

3.
结合洪都航空工业集团科研和生产的实际情况,从型号研制与生产的角度人笔,阐述了电子档案管理存在的问题,并提出了解决办法。  相似文献   

4.
首先,介绍了修正侧风的三种基本方法和基本原理,指出了着陆下滑阶段修正侧风应注意的问题。其次,分析了侧风对着陆拉平和平瓢阶段以及对不同机种飞机着陆滑跑方向的影响及其修正方法。再次,介绍了侧风条件下不同机种飞机减速伞的使用特点。最后,重点分析了带偏侧角接地及滑跑的成因、危害、预防措施及处理方法等。侧重于实际操纵特点的介绍与分析,对侧风着陆安全具有一定的理论指导作用。  相似文献   

5.
随着现代科学技术尤其是信息技术的快速发展 ,航空产品的科研生产出现了一系列新的变化。本文结合我国国情 ,探讨了制定航空产品科研生产流程的新思路 ,并对敏捷制造和精益生产作了较详细的叙述  相似文献   

6.
7.
In order to get the maximum scientific return from available resources, the wave experimenters on Cluster established the Wave Experiment Consortium (WEC). The WEC's scientific objectives are described, together with its capability to achieve them in the course of the mission. The five experiments and the interfaces between them are shown in a general block diagram (Figure 1). WEC has organised technical coordination for experiment pre-delivery tests and spacecraft integration, and has also established associated working groups for data analysis and operations in orbit. All science operations aspects of WEC have been worked out in meetings with wide participation of investigators from the five WEC teams.  相似文献   

8.
Boynton  W.V.  Feldman  W.C.  Mitrofanov  I.G.  Evans  L.G.  Reedy  R.C.  Squyres  S.W.  Starr  R.  Trombka  J.I.  d'Uston  C.  Arnold  J.R.  Englert  P.A.J.  Metzger  A.E.  Wänke  H.  Brückner  J.  Drake  D.M.  Shinohara  C.  Fellows  C.  Hamara  D.K.  Harshman  K.  Kerry  K.  Turner  C.  Ward  M.  Barthe  H.  Fuller  K.R.  Storms  S.A.  Thornton  G.W.  Longmire  J.L.  Litvak  M.L.  Ton'chev  A.K. 《Space Science Reviews》2004,110(1-2):37-83
The Mars Odyssey Gamma-Ray Spectrometer is a suite of three different instruments, a gamma subsystem (GS), a neutron spectrometer, and a high-energy neutron detector, working together to collect data that will permit the mapping of elemental concentrations on the surface of Mars. The instruments are complimentary in that the neutron instruments have greater sensitivity to low amounts of hydrogen, but their signals saturate as the hydrogen content gets high. The hydrogen signal in the GS, on the other hand, does not saturate at high hydrogen contents and is sensitive to small differences in hydrogen content even when hydrogen is very abundant. The hydrogen signal in the neutron instruments and the GS have a different dependence on depth, and thus by combining both data sets we can infer not only the amount of hydrogen, but constrain its distribution with depth. In addition to hydrogen, the GS determines the abundances of several other elements. The instruments, the basis of the technique, and the data processing requirements are described as are some expected applications of the data to scientific problems.  相似文献   

9.
Transition between high altitude manned observatories and unmanned balloon-borne or rocket-borne experiments is achieved with high flying aircrafts, at altitudes above tropopause (>12 km), which became readily available, at reasonable cost and reliability, in the past five or ten years.This paper reviews the development of scientific uses of aircrafts, especially for astronomy and geophysics, with some emphasis placed on infrared problems, closely related to the scale height of the chief infrared absorber, i.e. telluric water vapor.Absorbers distribution vs altitude and spectral characteristics are summarized (Figures 1, 2, 3).Capabilities of various available aircrafts are compared (Table I) and the various ways to consider modifications are discussed: structural modifications or design problems to fit telescopes or light collectors on board. Tables II and III list the advantages of airborne observations, compared to other spatial carriers, and also the specific problems connected with aircrafts. Adopted solutions to these problems are exposed (Figures 4, 5, 6, 7) and costs are briefly discussed.Finally, a few examples of scientific results, gathered in the few past years from aircraft, are given, both in astronomy and in geophysics.  相似文献   

10.
11.
软件复用技术在科学计算软件中的应用研究   总被引:4,自引:0,他引:4  
首先介绍多层软件复用技术及它的两个实践形式,并讨论软件复用的应用策略;接着探讨适合科学计算软件的开发模型;然后,描述民用飞机性能计算软件的开发以说明软件复用;最后,提出软件复用在科学计算软件开发中的需注意的几点事项以及今后应用研究的方向.  相似文献   

12.
A review of the development of photographic tracking techniques in different countries during the recent 5–6 yr is given. Main results of scientific investigations based on observations with Baker-Nunn cameras are considered. New large Soviet, English, French, German cameras are described. Important international projects on photographic tracking for satellite geodesy are reviewed. Main directions of research in this domain are discussed.  相似文献   

13.
在深入学习和实践科学发展观的活动中,正确认识陕西高等职业教育的发展状况,认真分析发展环境,查找发展中存在的突出问题,提出推进陕西高等职业院校,特别是民办高等职业院校科学发展的有效措施.使陕西的高职教育真正步入"以服务为宗旨,以就业为导向,特色发展、内涵发展"的科学发展之路.  相似文献   

14.
阐述了无切口连续拉深成形的工艺分析思路和模具设计要点,并对实际生产中出现的问题进行了剖析,给出了解决问题的办法。  相似文献   

15.
在我国高职高专教育事业蓬勃发展的同时,高职高专教育教学研究室院校学报已成长为一支生力军。高职高专院校学报既是各高职院校学术交流的宣传交流窗口,又是广大教师展示科研成果与技术创新成果的有效平台。学报的论文发表与交流,既可以提高教师的业务水平,又可以进一步提升学校教学、科研的整体水平,使学校形成一个良好的学术氛围,对推动高职高专教育的发展起到良好的促进作用。虽然高职高专院校学报起步晚,底子薄,经验少,但是依据自身的优势和地方特点,坚持特色办刊的理念,多数学报已经成为了独树一帜的学术交流平台。  相似文献   

16.
行动研究是一种将行动和研究恰当融合在一起的范式研究,它强调研究者即行动者,可以促使研究者科学而理性地研究工作中遇到的问题,从而达到解决实际问题的根本目的。公共英语教师的科研实践能力是大学英语教学改革和教学质量提高的源泉。科学、有效地在教学中进行行动研究,必然会帮助公共英语教师在完成繁重教学任务的同时实现自身科研实践能力的提升。  相似文献   

17.
军工科研院所的人力资源管理   总被引:1,自引:0,他引:1  
通过对军工科研院所人力资源管理面临问题的研究,提出了相应的对策。军工科研院所要求生态、求发展,必须把人力资源的管理工作提高到战略管理的层次,人力资源政策必须同本单位的科研发展、技术创新战略同步制定。  相似文献   

18.
Four sample electronic warfare (EW) problems are described in an effort to stimulate thought on various basic issues and assumptions encountered in EW and other fields. The problems are choosing a better sensor, transmitter, sequence, and search strategy  相似文献   

19.
In radar systems, extended Kalman-Bucy filters (EKBFs) are used to estimate state vectors of objects in track. Filter models accounting for fundamental aerodynamic forces on reentry vehicles are well known. A general model structure accommodating the dynamics of reentry vehicles in both exoatmospheric and endoatmospheric flight is presented. The associated EKBFs for these various models are described and the resulting associated parameter estimation and identification problems are discussed. The effects of position, velocity, drag, and aerodynamic lift are described within a nested set of EKBF models  相似文献   

20.
Aerothermodynamics is a branch of gas dynamics which is usually considered for continuum media. But many problems of gas dynamics cannot be solved and even properly understood in the framework of continuum media, and cannot be described on the macroscopic level. The aim of this review is to consider some problems of a continuum flow regime which cannot be solved without regarding the gas as a collection of molecules. Some of these problems are important for aerothermodynamics today. Others open up new ways, new possibilities and new questions.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号