全文获取类型
收费全文 | 230篇 |
免费 | 25篇 |
国内免费 | 5篇 |
专业分类
航空 | 43篇 |
航天技术 | 157篇 |
航天 | 60篇 |
出版年
2023年 | 5篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 15篇 |
2013年 | 13篇 |
2012年 | 18篇 |
2011年 | 23篇 |
2010年 | 16篇 |
2009年 | 16篇 |
2008年 | 19篇 |
2007年 | 5篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 7篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1984年 | 2篇 |
排序方式: 共有260条查询结果,搜索用时 546 毫秒
81.
空间环境是诱发卫星异常和故障的主要原因之一。光学遥感器作为卫星最重要的有效载荷之一,在空间会受到空间辐射环境的影响。因此在研制光学遥感器的同时,需要同时考虑空间辐射环境因素,文章就空间光学遥感器天然辐射效应数据库的设计和应用进行了介绍。 相似文献
82.
83.
为提升SRAM型FPGA电路块存储器和配置存储器抗单粒子翻转性能,本文提出一种脉冲屏蔽SRAM单元结构。该结构通过在标准的六管单元中加入延迟结构,增大单元对单粒子事件响应时间,实现对粒子入射产生的脉冲电流屏蔽作用。以64k SRAM作为验证电路进行单粒子翻转性能对比,电路的抗单粒子翻转阈值由采用标准六管单元的抗单粒子翻转阈值大于25 MeV·cm 2·mg -1 提升至大于45 MeV·cm 2·mg -1 ,加固单元面积较标准六管单元增大约21.3%。30万门级抗辐照FPGA电路通过脉冲屏蔽单元结合抗辐照SOI工艺实现,其抗辐照指标分别为:抗单粒子翻转阈值大于37.3 MeV·cm 2·mg -1 ,抗单粒子锁定阈值大于99.8 MeV·cm 2·mg -1 ,抗电离总剂量能力大于200 krad(Si)。 相似文献
84.
To improve the computational efficiency and hold calculation accuracy at the same time,we study the parallel computation for radiation heat transfer. In this paper, the discrete ordinates method(DOM) and the spatial domain decomposition parallelization(DDP) are combined by message passing interface(MPI) language. The DDP–DOM computation of the radiation heat transfer within the rectangular furnace is described. When the result of DDP–DOM along one-dimensional direction is compared with that along multi-dimensional directions, it is found that the result of the latter one has higher precision without considering the medium scattering. Meanwhile, an in-depth study of the convergence of DDP–DOM for radiation heat transfer is made. Analyzing the cause of the weak convergence, we relate the total number of iteration steps when the convergence is obtained to the number of sub-domains. When we decompose the spatial domain along one-,two- and three-dimensional directions, different linear relationships between the number of total iteration steps and the number of sub-domains will be possessed separately, then several equations are developed to show the relationships. Using the equations, some phenomena in DDP–DOM can be made clear easily. At the same time, the correctness of the equations is verified. 相似文献
85.
Calculation of high-temperature insulation parameters and heat transfer behaviors of multilayer insulation by inverse problems method 总被引:1,自引:0,他引:1
In the present paper, a numerical model combining radiation and conduction for porous materials is developed based on the finite volume method. The model can be used to investigate high-temperature thermal insulations which are widely used in metallic thermal protection systems on reusable launch vehicles and high-temperature fuel cells. The effective thermal conductivities(ECTs) which are measured experimentally can hardly be used separately to analyze the heat transfer behaviors of conduction and radiation for high-temperature insulation. By fitting the effective thermal conductivities with experimental data, the equivalent radiation transmittance, absorptivity and reflectivity, as well as a linear function to describe the relationship between temperature and conductivity can be estimated by an inverse problems method. The deviation between the calculated and measured effective thermal conductivities is less than 4%. Using the material parameters so obtained for conduction and radiation, the heat transfer process in multilayer thermal insulation(MTI) is calculated and the deviation between the calculated and the measured transient temperatures at a certain depth in the multilayer thermal insulation is less than 6.5%. 相似文献
86.
M.V. Podzolko I.V. Getselev Yu.I. Gubar I.S. Veselovsky A.A. Sukhanov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Charged particle fluxes on the trajectory of future Russian space research mission to Jupiter and its satellite Europa are investigated. The existing experimental data and models of Jupiter’s main magnetic field and radiation belts are summarized. Preliminary results of computations of energetic particle fluxes and radiation doses for each stage of the flight are given. Special attention is paid to estimation of radiation conditions in Europa’s orbit and on its surface; influence of the satellite on spatial distribution of the fluxes of charged particles of various energies is studied. 相似文献
87.
P.A. Curran R.L.C. Starling A.J. van der Horst R.A.M.J. Wijers M. de Pasquale M. Page 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The complex structure of the light curves of Swift GRBs (e.g. superimposed flares and shallow decay) has made their interpretation and that of the blast wave caused by the burst, more difficult than in the pre-Swift era. We aim to constrain the blast wave parameters: electron energy distribution, p, density profile of the circumburst medium, k, and the continued energy injection index, q. We do so by comparing the observed multi-wavelength light curves and X-ray spectra of a Swift sample to the predictions of the blast wave model. 相似文献
88.
89.
王家胜 《中国空间科学技术》1987,(6)
本文从点源的Sommerfeld型积分表达式出发,给出了计算在部分烧蚀介质层中或附近的水平线天线辐射场的公式。也给出了一些具有实用意义的计算例,卉-进行了有关讨论。 相似文献
90.
红外诱饵等空间特定目标是对抗红外探测的主要手段之一。随着双色制导技术的发展,红外探测灵敏度不断提升,目标识别能力不断增强,这对空间特定目标表面的双波段红外辐射的逼真性提出了要求。通过改变空间特定目标表面发射率控制其红外辐射强度的大小,使用数值仿真的方法进行计算,从而提出了对空间特定目标表面红外辐射特性的调控方法。此外根据所确定的表面发射率、可见光吸收及红外发射比例以及内热源功率,选择合适的表面材料以及热功率施加方法,在保证空间特定目标表面机械性能的同时,使空间特定目标满足光照及阴影区的双波段红外辐射特性要求,并进行模型的制作以及热真空实验,证明了理论计算的准确性。 相似文献