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   26篇
  免费   0篇
航空   7篇
航天技术   6篇
综合类   2篇
航天   11篇
  2017年   1篇
  2016年   3篇
  2014年   1篇
  2013年   1篇
  2012年   1篇
  2011年   1篇
  2009年   2篇
  2008年   3篇
  2005年   3篇
  2002年   1篇
  2001年   2篇
  1996年   3篇
  1985年   1篇
  1984年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有26条查询结果,搜索用时 31 毫秒
1.
2.
Despite the importance of space to modern life, the public has lost interest in its most human aspect, exploration. This is because spacefaring nations, and especially the USA, have clung on to outmoded cold war ways of thinking about it. The US attitude of ‘command’ over its international partners will no longer work and we must instead adopt a new, inclusive paradigm in the ‘wiki’ mould. With different countries leading different facets of a global, cooperative endeavour, and contributions reciprocated in ways valuable to all participants (e.g. through access to know-how or capacity building) there is a real possibility of advancing beyond near-Earth orbit. Keeping the ISS open for the training of future long-duration crews would be the first step in a unified human drive to the Moon, involving first a robotic village and then an international base, with Mars an ultimate goal. It the USA were to reorient its thinking towards such a project it would demonstrate true leadership.  相似文献   
3.
Jacques Blamont   《Space Policy》2008,24(1):13-21
The creation of Google Earth has initiated a new market for space imaging with hundreds of millions of potential customers. The distribution of data could replace their production as the driving factor in the development of the image business, up to the point where the managers of the flow of information would control and finance the space system, as operators do with satcoms.  相似文献   
4.
基于基因算法与博奕论的翼型跨音速Euler方程气动优化   总被引:3,自引:0,他引:3  
将基因算法与博奕论中的 Nash平衡相结合 ,构建了多目标基因优化算法—— Nash基因算法 (NashGAs) ,并对初始翼型为 NACA0 0 1 2二维翼型进行给定跨音速流动下的形状增升优化。计算中应用 Bézier曲线对翼型形状进行参数化 ,避免了非流线型的不合理形状产生 ;采用有限元非结构网格 AUSM+通量分裂格式Euler方程数值解进行个体适应度值评估 ;应用动态网格技术调整计算网络 ,节约了 CPU机时 ;最后给出了优化结果  相似文献   
5.
Jacques Blamont   《Space Policy》2005,21(2):89-92
France and the USA have in the past enjoyed a close and fruitful cooperative relationship in space but there is now a growing divergence between apparent US priorities for future activity and those of other countries, for whom human spaceflight is not so important. While accepting that it cannot match the USA technologically, Europe is increasingly sceptical of the wisdom of pursuing space cooperation with its given difficulties caused by the ITAR regime, greater suspicion of anything foreign in the USA and the unwillingness of NASA ever to cede a critical path to a partner. Nor are any of the non-space ventures currently being suggested as cooperation models attractive from a European point of view. A better way forward would be to have conglomerates of nations cooperating on an equal footing and avoiding recourse to US State Department-regulated technology.  相似文献   
6.
This study investigated novices' “lived experiences” of navigation within the sport of orienteering from an enactive and phenomenological approach. The objective was to qualitatively characterize elements of task-related situations that were meaningful for orienteers. The results showed that the participants continuously made judgments about the reliability of their estimations about whether they were on “the right route” on the course. When the participants judged that they were only approximately on the right route or were unable to locate themselves, elements of the situation other than map and terrain features became meaningful for them. These results demonstrate that, for novice orienteers, navigation activity must extend beyond navigation as a logical, computational way-finding problem to include embodied, social, cultural and situated dimensions.  相似文献   
7.
Timmery S  Hu X  Mahillon J 《Astrobiology》2011,11(4):323-334
Bacillus and related genera comprise opportunist and pathogen species that can threaten the health of a crew in confined stations required for long-term missions. In this study, 43 Bacilli from confined environments, that is, the Antarctic Concordia station and the International Space Station, were characterized in terms of virulence and plasmid exchange potentials. No specific virulence feature, such as the production of toxins or unusual antibiotic resistance, was detected. Most of the strains exhibited small or large plasmids, or both, some of which were related to the replicons of the Bacillus anthracis pXO1 and pXO2 virulence elements. One conjugative element, the capacity to mobilize and retromobilize small plasmids, was detected in a Bacillus cereus sensu lato isolate. Six out of 25 tested strains acquired foreign DNA by conjugation. Extremophilic bacteria were identified and exhibited the ability to grow at high pH and salt concentrations or at low temperatures. Finally, the clonal dispersion of an opportunist isolate was demonstrated in the Concordia station. Taken together, these results suggest that the virulence potential of the Bacillus isolates in confined environments tends to be low but genetic transfers could contribute to its capacity to spread.  相似文献   
8.
A compact Dopplergraph/magnetograph placed in a continuous solar-viewing orbit will allow us to make major advancements in our understanding of solar internal structure and dynamics. An international program is currently being conducted at JPL and Mt. Wilson to develop such an instrument. By combining a unique magneto-optical resonance filter with CID and CCD cameras we have been able to obtain full- and partial-disk Dopplergrams and magnetograms. Time series of the velocity images are converted into k-ω power spectra which show clear- the solar nonradial p-mode oscillations. Magnetograms suitable for studying the long-term evolution of solar active regions have also been obtained with this instrument. A flight instrument based on this concept is being studied for possible inclusion in the SOHO mission.  相似文献   
9.
Ethical issues have for long been limited to the fields of medicine and biotechnology, whereas to-day such matters encompass a growing number of engineering activities. 21st century citizens are more equiring about technoscientific claims and accomplishments. Has their impact on society and the ecological environment been measured and quantified? With all this accumulated knowledge and progress do they have the ability and means to resolve these self-created difficulties? Or will a totally new approach have to be sought? The debates include space activity not only because of the public funding needed but also because of the possible consequences on humans as well as the terrestrial, orbital or outer environment. Since the fall of 1998, CNES has undertaken the study of the role played by space activities in to-day's society and that of the future, seeking to clarify the objectives of the former with the expectations of the latter, and how they converge. The purpose of this study is to determine precisely the ethical responsibility of the space agencies and to pursue more sociological and philosophical research on the ethical scope of space activities.  相似文献   
10.
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