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71.
卫星高压气瓶的超高速撞击试验 总被引:1,自引:0,他引:1
微流星体及空间碎片超高速撞击对在轨航天器构成了严重威胁,星上压力容器受空间碎片撞击后所产生的威胁是十分严重的,可能导致航天器发生灾难性失效,过早结束其使命。文章通过星上常用气瓶的超高速撞击试验,获取了不同弹丸撞击参数下气瓶器壁的通孔孔径,得到了在弹丸撞击速度为(6.5±0.3)km/s、无防护情况下气瓶器壁的弹道极限,并分析了导致充压气瓶灾难性失效的弹丸直径范围;通过对试验数据拟合,初步建立了弹丸正撞击速度为(6.5±0.3)km/s、无防护情况下气瓶器壁的通孔孔径预测公式,为航天器遭遇空间碎片撞击的风险评估及防护措施制定提供依据。 相似文献
72.
耐高温聚酰亚胺结构胶黏剂的研究 总被引:2,自引:0,他引:2
合成了以苯乙炔基封端的系列聚酰亚胺胶黏剂,研究了分子结构、分子量、固化工艺等因素对其耐热和粘接性能的影响规律.结果表明:合成的聚酰亚胺胶黏剂具有优异的耐热和高温粘接性能,对不锈钢试片粘接的剪切强度在316℃下≥10 MPa,在400℃下为3 MPa. 相似文献
73.
翼型表面粗糙度对结冰的影响分析 总被引:1,自引:0,他引:1
飞机的结冰表面出现微小的凹凸不平,即形成所谓的粗糙度,对飞机气动性能产生一定的影响。在考虑表面粗糙度时,针对对流换热系数的计算建立了热力学模型,同时对只有单个粗糙微元的表面进行了流场计算和表面对流换热效果分析;然后利用边界层积分方法,对某一翼型光滑表面和不同程度的粗糙表面分别进行了流场计算、对流换热系数计算以及结冰冰形的模拟仿真。结果表明:结冰表面粗糙度很大程度增强了表面的对流换热效果,导致在翼型前缘位置结冰厚度更大、冰角突出更为明显并且距离驻点区域更近。 相似文献
74.
Jian-zhao Wang Ji-nan Ma Zhuo-xi Huo Ying Xiong Dai Tian 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(5):1709-1720
The Juno spacecraft made the first in-situ observations of energetic particles in the polar region of Jupiter’s magnetosphere. After Jupiter Orbit Insertion (JOI) in July 2016, data from ~20 Juno perijoves (PJs) obtained by Juno/JEDI are accumulated, providing an excellent opportunity to study the long term spatio-temporal distribution of energetic particles in Jupiter’s radiation belt. We transform Juno’s position from a Cartesian to a magnetic coordinate system by tracing magnetic field lines based on a fourth order Runge-Kutta method. Then the fluxes of energetic electrons from PJ1 to PJ14 sorted by different locations in magnetic coordinate space and the data are well organized by the L-shell parameter. The variation of electron flux increases with L-shell. The deviation (the ratio of the 75th percentile to the 25th percentile) of 0.51 MeV electron flux varies from a factor of 1.23 near L = 9.5 to 27.57 near L = 15.5. However, the mean flux decreases by about one order of magnitude in the same region. The electron spectra at larger L-shells are softer than that at smaller L-shells. On the other hand, the electron flux decreases more rapidly with increased L-shell when the location is off the equator. Along an L-shell, the electron flux decrease at first and then increase again from equator to mid-latitude region. In addition, we compare the statistical results with the widely used GIRE2 model. JEDI data correspond well with the GIRE2 model when the L-shell is > 14.75. GIRE2 underestimate the electron flux for L-shell smaller than 13.25. These results of this analysis are applicable to estimate the effects of the radiation environment in Jupiter’s magnetosphere. 相似文献
75.
Xuefeng Tao Zhi Li Can Xu Yurong Huo Yasheng Zhang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(8):2304-2318
This paper focuses on the track-to-object association problem based on the two-line elements (TLE) set. The TLE’s short-term propagation error characteristics are analyzed to capture its uncertainty. Further, a four-step track-to-object association algorithm is designed for the optical observation data. First, for too-short arc tracklets, a circular orbit determination algorithm is proposed to calculate the inclination and the right ascension of the ascending node. Second, the TLEs are filtered based on these results. Nearly 96% of the TLEs can be filtered, which significantly improves the association efficiency. The last two steps consist of two association processes. A first-order association process is implemented first to get candidate objects, with the angles root mean square error as the metric. Then a precise association process checks the candidate objects and gives the final association result. The proposed approach is tested with simulated and observed data, respectively. With simulated data, the true positive rate is 98.7%. With the observed data, the association results were validated using the precise orbit ephemerides. 相似文献
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