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排序方式: 共有1317条查询结果,搜索用时 687 毫秒
811.
812.
便携式红外寻的防空导弹初制导探索 总被引:1,自引:0,他引:1
对便携式红外寻的防空导弹的初制导进行了定性研究。根据期望前置角,讨论了导弹发射出筒后的侧向力控制方案,给出了发射时下沉的补偿措施。分析了俄制针式便携式红外寻的防空导弹初制导系统的控制律并进行了讨论。 相似文献
813.
S. Ohtsuki N. Iwagami H. Sagawa M. Ueno Y. Kasaba T. Imamura E. Nishihara 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(9):1375-1380
Several ground-based observations of the Venus 1.27-μm O2 airglow were carried out from 2002 to 2005. Spectral image cubes were taken with the Okayama Astrophysical Observatory/infrared imaging spectrometer (superOASIS), the Gunma Astronomical Observatory/Cassegrain Near-Infrared Camera and NASA’s Infrared Telescope Facility/cryogenic echelle spectrograph (CSHELL). The brightest airglow features were found at around the anti-solar point, which is in agreement with previous studies. We derived the rotational temperature distributions on the nightside hemisphere from observed airglow spectra. The temperature shows a weak positive correlation with the airglow intensity. The result indicates the bright region is heated chemically and/or dynamically, and supports the existing scenario for the Venus O2 airglow. That is, the airglow is excited by the descending oxygen transported from the dayside. 相似文献
814.
非额定条件下变压器损耗测量研究 总被引:1,自引:0,他引:1
任仁良 《中国民航学院学报》1996,(6):44-50
讨论了利用单片机技术测量变压器损耗的基本方法.推导了在非额定电压下测量变压器空载损耗的数学模型及其软件结构.最后给出实践结果. 相似文献
815.
对搞好天津高校健康教育的初探 总被引:2,自引:0,他引:2
郝力行 《中国民航学院学报》1997,15(2):76-78
通过不同侧面说明在高校开展健康教育的意义,简要介绍了我市高校开展健康教育的现状,提出了促进我市高校开展健康教育的看法。 相似文献
816.
The Local Interstellar Cloud (LIC) surrounds the Solar System and sets the boundary conditions for the heliosphere. Using
both in situ and absorption line data towards ε CMa we are able to constrain both the ionization and the gas phase abundances of the LIC gas at the Solar Location. We find
that the abundances are consistent with all of the carbonaceous dust grains having been destroyed, and in fact with a supersolar
abundance of C. The constituents of silicate grains, Si, Mg, and Fe, appear to be sub-solar, indicating that silicate dust
is present in the LIC. N, O and S are close to the solar values. 相似文献
817.
为了提升复杂目标红外辐射特性建模效率及置信度问题,提出一种目标红外辐射特性的大数据知识表示及建模方法。首先利用机理分析法、主成分分析法确定目标红外辐射特性大数据维度;然后基于主成分分析的结果,进行目标红外辐射特性大数据知识表示,建立目标红外辐射特性仿真模型;最后进行模型的仿真应用,在应用过程中进一步完善目标红外辐射特性数据或知识表示。本文提供的大数据驱动的目标红外辐射特征建模方法,能够推广应用于复杂电磁环境的仿真。 相似文献
818.
贺东梅 《华北航天工业学院学报》2001,(1)
本文从电信网、广播电视网和因特网三种网络的不同特点入手,说明了三网合一的必要性和可行性,重点探讨了三网合一中关键的接入网技术。 相似文献
819.
The European Large Area ISO Survey (ELAIS) was the largest Open Time survey on the Infrared Space Observatory (ISO). It was
designed to explore obscured galaxies and hence quantify the recent star-formation history of the Universe. The final reanalysis
of the data has been completed and a band-merged catalogue with associations across many wavelengths compiled and released
the data to the global astronomical community (http://astro.imperial.ac.uk/Elais/). This paper summarises some of the key
results.
Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries:
France, Germany, The Netherlands, and the United Kingdom), and with the participation of ISAS and NASA. 相似文献
820.
The differences between the composition of Galactic cosmic rays and that of the interstellar medium are manifold, and they
contain a wealth of information about the varying processes that created them. These differences reveal much about the initial
mixing of freshly synthesized matter, the chemistry and differentiation of the interstellar medium, and the mechanisms and
environment of ion injection and acceleration. Here we briefly explore these processes and show how they combine to create
the peculiar, but potentially universal, composition of the cosmic rays and how measurements of the composition can provide
a unique measure of the mixing ratio of the fresh supernova ejecta and the old interstellar medium in this initial phase of
interstellar mixing.
In particular, we show that the major abundance differences between the cosmic rays and the average interstellar medium can
all result from cosmic ray ion injection by sputtering and scattering from fast refractory oxide grains in a mix of fresh
supernova ejecta and old interstellar material. Since the bulk of the Galactic supernovae occur in the cores of superbubbles,
the bulk of the cosmic rays are accelerated there out of such a mix. We show that the major abundance differences all imply
a mixing ratio of the total masses of fresh supernova ejecta and old interstellar material in such cores is roughly 1 to 4.
That means that the metallicity of ∼3 times solar, since the ejecta has a metallicity of ∼8 times that of the present interstellar
medium. 相似文献