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871.
Malini Aggarwal H.P. Joshi K.N. Iyer M.N. Jivani 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Solar dependence of electron and ion temperatures (Te and Ti) in the ionosphere is studied using RPA data onboard SROSS C2 at an altitude of ∼500 km and 77°E longitude during early morning hours (04:00–07:00 LT) for three solar activities: solar minimum, moderate and maximum during winter, summer and equinox months in 10°S–20°N geomagnetic latitude. In winter the morning overshoot phenomenon is observed around 06:00 LT (Te enhances to ∼4000 K) during low-solar activity and to Te ∼ 3800 K, during higher solar activity. In summer, it is observed around 05:30 LT, but the rate of Te enhancement is higher during moderate solar activity (∼2700 K/hr) than the low-solar activity (∼1700 K/hr). During equinox, this phenomenon is delayed and is observed around 06:00 LT (∼4200 K) during all three activities. 相似文献
872.
873.
Alexander Ruzmaikin Jae N. Lee Dong L. Wu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
We determine the spatial-time patterns of zonally averaged carbon monoxide (CO) in the middle atmosphere by applying Principle Component Analysis to the CO data obtained from the Microwave Limb Sounder (MLS) measurements on the Aura satellite in 2004–2012. The first two principal components characterize more than 90% of the CO variability. Both principal components are localized in the low thermosphere near the mesopause. The first principal component is asymmetric relative to the poles. It has opposite signs in the Northern and Southern Hemisphere at mid to high latitudes and strongly oscillates with an annual periodicity. The second principal component has the same sign in both hemispheres and oscillates mainly with a semi-annual frequency. Both principal components are modulated by the 11-year solar cycle and display short-term variations. To test possible correlations of these variations with the short term solar ultraviolet (UV) variability we use the simultaneous measurements of the UV solar radiance from the Solar-Stellar Irradiance Comparison Experiment (SOLSTICE) on the Solar Radiation and Climate Experiment (SORCE) satellite to investigate the correlation between CO in the middle atmosphere and solar UV in 2004–2012. Using a wavelet coherence technique a weak, intermittent 27-day signal is detected in high-frequency parts of the CO principal components. 相似文献
874.
Jia Huang James D. Biggs Yuliang Bai Naigang Cui 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(9):2823-2833
Current control approaches for solar sail station-keeping on libration point orbits have not considered the degradation of the sail’s optical properties. However, significant optical degradation could lead to poor station-keeping performance or even complete failure. This paper presents an integrated guidance and control strategy to address this problem by updating the reference orbit based on in situ estimation. An exponential optical degradation model is incorporated into the solar radiation acceleration model, and an on-line reference orbit update approach is incorporated into the station-keeping, coupled with an active disturbance rejection controller. The reflection coefficient is estimated on-line and the reference orbit is updated discretely when the optical properties have degraded by a prescribed amount. This strategy provides discrete updates to the reference orbits such that the perturbation due to the optical degradation is maintained within a small range. These smaller perturbations can be dealt with by the controller’s robustness and station-keeping can be sustained for long durations even in the presence of large optical degradation. 相似文献
875.
地空导弹防太阳辐射的论证、设计与试验 总被引:1,自引:0,他引:1
介绍了太阳辐射的基本概念、能量分布情况及其对地空导弹武器装备的影响,给出了论证地空导弹武器环境适应性时太阳辐射强度取值的依据、降低太阳辐射影响的措施和太阳辐射试验的参数取值依据以及对试验设备的要求,可供从事环境适应性论证、设计与试验工作的人员参考。 相似文献
876.
E.I. Astafyeva E.L. Afraimovich A.V. Oinats Yu.V. Yasukevich I.V. Zhivetiev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
We analyzed the dynamics of global electron content (GEC) for the period 1998–2005 and compared the estimated GEC with variations of the 10.7-cm solar radio emission and with and with GEC values obtained with IRI-2001. We found a strong resemblance between the curves’ shapes for the experimental and modeled GEC: strong semiannual variations are discernible in these series and both curves tend to increase the absolute GEC value during the period of maximum of solar activity. However, there are some significant distinctions, such as absence of 27-day fluctuations in the series of GEC computed by the IRI-2001. On the contrary, observational GEC reflects well dynamics of solar activity: 27-day variations of GEC are very similar to the ones of the index F10.7, but GEC undergoes a lagging of about of 30–60 h as compared to value of the F10.7 index. The relative amplitude of 27-day variations decreases from 8% at the rising and falling solar activity to 2% at the period of its maximum. 相似文献
877.
王伟志 《运载火箭与返回技术》2007,28(2):1-4,48
文章简要阐述了太阳帆的概念、主要结构和技术,参考美国L’Garde公司的太阳帆展开设计,对涉及的充气及刚化予以概述,为研究分析太阳帆的展开技术提供借鉴。 相似文献
878.
H. Mavromichalaki A. Papaioannou C. Plainaki C. Sarlanis G. Souvatzoglou M. Gerontidou M. Papailiou E. Eroshenko A. Belov V. Yanke E.O. Flückiger R. Bütikofer M. Parisi M. Storini K.-L. Klein N. Fuller C.T. Steigies O.M. Rother B. Heber R.F. Wimmer-Schweingruber K. Kudela I. Strharsky R. Langer I. Usoskin A. Ibragimov A. Chilingaryan G. Hovsepyan A. Reymers A. Yeghikyan O. Kryakunova E. Dryn N. Nikolayevskiy L. Dorman L. Pustil’nik 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
A high-time resolution Neutron Monitor Database (NMDB) has started to be realized in the frame of the Seventh Framework Programme of the European Commission. This database will include cosmic ray data from at least 18 neutron monitors distributed around the world and operated in real-time. The implementation of the NMDB will provide the opportunity for several research applications most of which will be realized in real-time mode. An important one will be the establishment of an Alert signal when dangerous solar cosmic ray particles are heading to the Earth, resulting into ground level enhancements effects registered by neutron monitors. Furthermore, on the basis of these events analysis, the mapping of all ground level enhancement features in near real-time mode will provide an overall picture of these phenomena and will be used as an input for the calculation of the ionization of the atmosphere. The latter will be useful together with other contributions to radiation dose calculations within the atmosphere at several altitudes and will reveal the absorbed doses during flights. Moreover, special algorithms for anisotropy and pitch angle distribution of solar cosmic rays, which have been developed over the years, will also be set online offering the advantage to give information about the conditions of the interplanetary space. All of the applications will serve the needs of the modern world which relies at space environment and will use the extensive network of neutron monitors as a multi-directional spectrographic detector. On top of which, the decreases of the cosmic ray intensity – known as Forbush decreases – will also be analyzed and a number of important parameters such as galactic cosmic ray anisotropy will be made available to the users of NMDB. A part of the NMDB project is also dedicated to the creation of a public outreach website with the scope to inform about cosmic rays and their possible effects on humans, technological systems and space-terrestrial environment. Therefore, NMDB will also stand as an informative gate on space research through neutron monitor’s data usage. 相似文献
879.
超轻型飞机AD100是我院自行设计的我国第一架鸭式布局旅游机。它由机身、主翼、中翼、前翼、翼尖小翼、起落架以及发动机等部件组成。飞机各个部件的轴测图或各部件组合轴测图以及全机外形图,可在IBM4341计算机上利用双三次B一样条曲面和改进的双主次Coons曲面算法,在TEK618上显示和在TEK4662绘图仪上绘制。本程序可在绘制中随意改变三维空间角度,並能绘制出飞机某部件及其切面图,以便于加工样板和绘制模线。 相似文献
880.
首先回顾了NASA的空间太阳电站1979 SPS基准系统方案及其产生与搁置的背景,强调了1995-1997年新一轮论证中所提方案的高度模块化特点,这一特点使空间太阳电站的技术可行性大为增加,其次介绍了空间电站研究的工作分解结构和所需的关键技术,最后从全球对电能的需求,有关国家的态度,关键技术的进展等几个方面,给出了对空间电站发展前景的不同评价。 相似文献