首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   14篇
  免费   0篇
航空   11篇
航天   3篇
  2013年   1篇
  2012年   2篇
  2011年   4篇
  2010年   2篇
  2009年   2篇
  2007年   1篇
  2005年   2篇
排序方式: 共有14条查询结果,搜索用时 31 毫秒
1.
经过二十几年的研发历程,美国海军的使用试验与评估部队最近确认V-22“鱼鹰”倾转旋翼机达到了作战效能和作战适用性要求,海军陆战队也认为该项目基本上接近了可以大批量生产的阶段。美国国防采办委员会很快将对该倾转旋翼机进行评审,如果进展顺利,预计首批12架V-22将在2007年投入使用。  相似文献   
2.
近年来,欧洲飞机制造商频频利用与美国本土制造商联手的方式,竞争美国军方的一些航空装备采购计划,以避开美国武器进口限制,将其产品打入美国军用市场。最近,在美国陆军未来货运飞机(FCA)采购项目的竞争中,两家欧洲飞机制造商又采用了同样的手段。  相似文献   
3.
Lunar Reconnaissance Orbiter Overview: The Instrument Suite and Mission   总被引:6,自引:0,他引:6  
NASA’s Lunar Precursor Robotic Program (LPRP), formulated in response to the President’s Vision for Space Exploration, will execute a series of robotic missions that will pave the way for eventual permanent human presence on the Moon. The Lunar Reconnaissance Orbiter (LRO) is first in this series of LPRP missions, and plans to launch in October of 2008 for at least one year of operation. LRO will employ six individual instruments to produce accurate maps and high-resolution images of future landing sites, to assess potential lunar resources, and to characterize the radiation environment. LRO will also test the feasibility of one advanced technology demonstration package. The LRO payload includes: Lunar Orbiter Laser Altimeter (LOLA) which will determine the global topography of the lunar surface at high resolution, measure landing site slopes, surface roughness, and search for possible polar surface ice in shadowed regions, Lunar Reconnaissance Orbiter Camera (LROC) which will acquire targeted narrow angle images of the lunar surface capable of resolving meter-scale features to support landing site selection, as well as wide-angle images to characterize polar illumination conditions and to identify potential resources, Lunar Exploration Neutron Detector (LEND) which will map the flux of neutrons from the lunar surface to search for evidence of water ice, and will provide space radiation environment measurements that may be useful for future human exploration, Diviner Lunar Radiometer Experiment (DLRE) which will chart the temperature of the entire lunar surface at approximately 300 meter horizontal resolution to identify cold-traps and potential ice deposits, Lyman-Alpha Mapping Project (LAMP) which will map the entire lunar surface in the far ultraviolet. LAMP will search for surface ice and frost in the polar regions and provide images of permanently shadowed regions illuminated only by starlight. Cosmic Ray Telescope for the Effects of Radiation (CRaTER), which will investigate the effect of galactic cosmic rays on tissue-equivalent plastics as a constraint on models of biological response to background space radiation. The technology demonstration is an advanced radar (mini-RF) that will demonstrate X- and S-band radar imaging and interferometry using light weight synthetic aperture radar. This paper will give an introduction to each of these instruments and an overview of their objectives.  相似文献   
4.
Our understanding of the composition of Ceres is driven by remote sensing of its surface. We review spectral observations of Ceres over wavelengths from the ultraviolet to the radio, as well as non-spectral data such as thermal inertia, photometric properties, radar experiments, and surface variability. We also discuss the closest likely meteorite analogs to Ceres and consider the likelihood that material from Ceres could be delivered to Earth.  相似文献   
5.
在北京暖暖的春光中,满载各方赞誉的第十二届中国国际机床展览会(CIMT 2011)圆满落下帷幕。中国国际机床展览会由中国机床工具工业协会主办,自1989年创办至今已经走过了23年历程,成功举办了12届。本届CIMT 2011展会更是取得了空前的成功,展会汇聚了来自全球28个国家和地区的1400多家业界厂商,众多知名企业悉数参展,使用了中国国际展览中心(新馆)全部8个展馆和1个临时馆,展出面积达12万m2。无论展会规模、展商数量、观众人数、展品数量和水平、展会成交额,还是国家领导人及社会各界的关注程度,都创造了历届CIMT展会和全国同类展会之最。  相似文献   
6.
在飞机和发动机的研制生产中,焊接技术已经成为关键工艺方法之一。其进步与发展不仅能减轻飞机和发动机的重量,而且还能为飞机和发动机新的结构设计提供技术上的支持,促进飞机和发动机性能的整体提升。  相似文献   
7.
北京市电加工研究所专业从事精密数控电加工机床制造和精密运动控制技术开发,是一个集科研、开发、生产于一体的高新技术企业。凭借完全掌握产品的核心技术和优质的产品服务过程  相似文献   
8.
Popa R  Smith AR  Popa R  Boone J  Fisk M 《Astrobiology》2012,12(1):9-18
The boundary between ice and basalt on Earth is an analogue for some near-surface environments of Mars. We investigated neutrophilic iron-oxidizing microorganisms from the basalt-ice interface in a lava tube from the Oregon Cascades with perennial ice. One of the isolates (Pseudomonas sp. HerB) can use ferrous iron Fe(II) from the igneous mineral olivine as an electron donor and O(2) as an electron acceptor. The optimum growth temperature is ~12-14°C, but growth also occurs at 5°C. Bicarbonate is a facultative source of carbon. Growth of Pseudomonas sp. HerB as a chemolithotrophic iron oxidizer with olivine as the source of energy is favored in low O(2) conditions (e.g., 1.6% O(2)). Most likely, microbial oxidation of olivine near pH 7 requires low O(2) to offset the abiotic oxidation of iron. The metabolic capabilities of this bacterium would allow it to live in near-surface, icy, volcanic environments of Mars in the present or recent geological past and make this type of physiology a prime candidate in the search for life on Mars.  相似文献   
9.
The Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment   总被引:1,自引:0,他引:1  
The Diviner Lunar Radiometer Experiment on NASA’s Lunar Reconnaissance Orbiter will be the first instrument to systematically map the global thermal state of the Moon and its diurnal and seasonal variability. Diviner will measure reflected solar and emitted infrared radiation in nine spectral channels with wavelengths ranging from 0.3 to 400 microns. The resulting measurements will enable characterization of the lunar thermal environment, mapping surface properties such as thermal inertia, rock abundance and silicate mineralogy, and determination of the locations and temperatures of volatile cold traps in the lunar polar regions.  相似文献   
10.
[编者按]机床盛会CIMT 2009结束了,但它展示给业内的新技术、新产品却影响深远,展会上各式复合加工机床纷纷亮相.那么此次展会反映了复合加工的哪些趋势?该技术在航空航天领域的应用情况如何?带着这些问题,本刊记者采访了北京机床研究所副总师盛伯浩先生.  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