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Dr Bess Reijnen 《Space Policy》1989,5(2)
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文章简要介绍了碳/环氧复合材料薄壁细长管件的研制情况,着重介绍了工艺方案选定、选材和材料特性试验、成型工艺及解决主要技术难点等内容。制品经地面环模和飞行试验考验,取得了满意效果。 相似文献
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Dr G. K. C. Pardoe 《Space Policy》1986,2(1)
This report on the commercial benefits of space does not seek to cover in depth all user sectors, but rather to establish an overview of what can be expected by users from the use of space. The growth of applications of technology to projects in the space field has been so rapid and broad, that it has overtaken the level of awareness by many sectors of the community of the benefits that space applications can offer. There is therefore a great need to broaden and deepen the level of awareness by many in the world community of what space is all about. These opportunities apply as much to the developing countries of the world as the developed ones. 相似文献
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集中涡法在计算旋成体大迎角气动特性中的应用 总被引:1,自引:0,他引:1
本文用集中涡法计算了尖头旋成体在大迎角时的气动特性。基于实验数据,选取了一组比较合适的自由积分参数,建立了初始分离角和雷诺数之间的经验关系式,从而在计算中较好地考虑了雷诺数的影响。马赫数的影响是通过Gthert法则进行修正予以考虑的。旋涡运动的微分方程组是用变步长的四阶龙格-库塔法来求解的。根据不同的积分位置分别选择三种不同的积分初始步长,以提高计算速度。本文对F_3A16和F3.5A7两种模型作了计算,计算结果和实验结果吻合得较好。 相似文献
115.
Emission heights of coronal bright points on Fe XII radiance map 总被引:1,自引:0,他引:1
H. Tian C.-Y. Tu J.-S. He E. Marsch 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2007,39(12):1853-1859
The study of coronal bright points (BPs) is important for understanding coronal heating and the origin of the solar wind. Previous studies indicated that coronal BPs have a highly significant tendency to coincide with magnetic neutral lines in the photosphere. Here we further studied the emission heights of the BPs above the photosphere in the bipolar magnetic loops that are apparently associated with them. As BPs are seen in projection against the disk their true emission heights are unknown. The correlation of the BP locations on the Fe XII radiance map from EIT with the magnetic field features (in particular neutral lines) was investigated in detail. The coronal magnetic field was determined by an extrapolation of the photospheric field (derived from 2-D magnetograms obtained from the Kitt Peak observatory) to different altitudes above the disk. It was found that most BPs sit on or near a photospheric neutral line, but that the emission occurs at a height of about 5 Mm. Some BPs, while being seen in projection, still seem to coincide with neutral lines, although their emission takes place at heights of more than 10 Mm. Such coincidences almost disappear for emissions above 20 Mm. We also projected the upper segments of the 3-D magnetic field lines above different heights, respectively, on to the tangent x–y plane, where x is in the east–west and y in the south–north direction. The shape of each BP was compared with the respective field-line segment nearby. This comparison suggests that most coronal BPs are actually located on the top of their associated magnetic loops. Finally, we calculated for each selected BP region the correlation coefficient between the Fe XII intensity enhancement and the horizontal component of the extrapolated magnetic field vector at the same x–y position in planes of different heights, respectively. We found that for almost all the BP regions we studied the correlation coefficient, with increasing height, increases to a maximal value and then decreases again. The height corresponding to this maximum was defined as the correlation height, which for most bright points was found to range below 20 Mm. 相似文献
116.
气动补偿空速管是与飞行安全性和飞机飞行的高度分层密切相关的重要器件,在改进现役飞机和设计新机空速系统中起着重要作用。本文依据多年来大量的气动计算和风洞实验所得到的结果,叙述了气动补偿空速管的原理、分类、设计思想、特点、风洞校准、气动计算、使用和发展等情况。 相似文献
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