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31.
C. Fröhlich 《Space Science Reviews》2006,125(1-4):53-65
Since November 1978 a set of total solar irradiance (TSI) measurements from space is available, yielding a time series of
more than 25 years. Presently, there are three TSI composites available, called PMOD, ACRIM and IRMB, which are all constructed
from the same original data, but use different procedures to correct for sensitivity changes. The PMOD composite is the only
one which also corrects the early HF data for degradation. The results from the detailed analysis of the VIRGO radiometry
allow a good understanding of the effects influencing the long-term behaviour of classical radiometers in space. Thus, a re-analysis
of the behaviour of HF/NIMBUS-7 and ACRIM-I/SMM was indicated. For the former the situation is complicated by the fact that
there are no in-flight means to determine changes due to exposure to solar radiation by comparison with a less exposed radiometer
on the same spacecraft. The geometry and optical property of the cavity of HF is, however, very similar to the PMO6-type radiometers,
so the behaviour of the PMO6V radiometers on VIRGO can be used as a model. ACRIM-I had to be revised mainly due to a henceforth
undetected early increase and a more detailed analysis of its degradation. The results are not only important for solar radiometry
from space, but they also provide a more reliable TSI during cycle 21. The differences between the revised PMOD composite
and the ACRIM and IRMB are discussed by comparison with a TSI reconstruction from Kitt-Peak magnetograms. As the PMOD composite
is the only one which has reliable data for cycle 21, the behaviour of the three solar cycles can now be compared and the
similarities and differences discussed. 相似文献
32.
Y. Futaana S. Barabash A. Grigoriev D. Winningham R. Frahm M. Yamauchi R. Lundin 《Space Science Reviews》2006,126(1-4):315-332
As a part of the global plasma environment study of Mars and its response to the solar wind, we have analyzed a peculiar case
of the subsolar energetic neutral atom (ENA) jet observed on June 7, 2004 by the Neutral Particle Detector (NPD) on board
the Mars Express satellite. The “subsolar ENA jet” is generated by the interaction between the solar wind and the Martian
exosphere, and is one of the most intense sources of ENA flux observed in the vicinity of Mars. On June 7, 2004 (orbit 485
of Mars Express), the NPD observed a very intense subsolar ENA jet, which then abruptly decreased within ∼10 sec followed
by quasi-periodic (∼1 min) flux variations. Simultaneously, the plasma sensors detected a solar wind structure, which was
most likely an interplanetary shock surface. The abrupt decrease of the ENA flux and the quasi-periodic flux variations can
be understood in the framework of the global response of the Martian plasma obstacle to the interplanetary shock. The generation
region of the subsolar ENA jet was pushed towards the planet by the interplanetary shock; and therefore, Mars Express went
out of the ENA jet region. Associated global vibrations of the Martian plasma obstacle may have been the cause of the quasi-periodic
flux variations of the ENA flux at the spacecraft location. 相似文献
33.
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35.
基于质子交换膜燃料电池(PEMFC)和热驱制冷,提出一种舱外航天服生命保障系统冷热电一体化方案.在分别建立金属储氢装置、PEMFC、热驱制冷系统和辐射散热器数学模型的基础上,利用冷热电一体化的热力学分析理论和方法进行了典型案例的计算,并重点分析了核心构件热驱制冷装置的参数对舱外航天服生命保障系统性能的影响.与传统的冷热电分产舱外航天服生命保障系统比较,该系统仅消耗84.6g氢气,且不需要向空间排放工质,能源利用率高达85.29%,在工质消耗与能源利用率上有较大的优势. 相似文献
36.
飞机研发是一项大型的系统性工程,传统的飞机产品结构由于零组件数据集包含有二维图纸、三维模型、临时更改单等大量文档且更改较频繁,同时制造、维修等部门在工程数据重构中存在工作量大和转换易脱节等特点,导致产品数据管理异常复杂和困难,效率也较低。为了简化飞机产品结构管理方式,在借鉴国际主流飞机制造商经验的基础上,通过结合模块化理论和全三维设计手段。以某一型号的民用飞机为例,重点从产品结构的组织模式、数据集的构成、产品数据的更改规则对该管理方案进行了阐述。从而保证了构型数据管理的便捷性和准确性,也符合未来飞机产品研发全数字化的发展方向。 相似文献
37.
飞船返回舱再入阶段高超声速六分量测力试验研究 总被引:3,自引:0,他引:3
介绍了在气动中心超高速所激波风洞中进行的飞船返回舱再入阶段高超声速六分量测力试验研究以及马赫数、雷诺数变化对返回舱外形纵向三分量气动特性的影响研究。在试验方案和天平设计中提出和采用了“5 l”方案,即五分量主天平和单分量滚转力矩天平实现六分量测量,模型分段连接使大轴向力对小滚转力矩测量的干扰降至最低。为考核该方案的可行性,还进行了一系列验证性试验,如对比性试验和缝隙影响试验,试验研究结果表明:采用该方案是可行的,成功地测量出了返回舱模型上的小滚转力矩。 相似文献
38.
鱼雷电源组件自动检测系统的设计与实现 总被引:1,自引:0,他引:1
叙述了鱼雷电源组件自动检测系统的设计与实现,对系统总体方案及程控电源设计、导通 绝缘性测量、操舵输出下降沿过渡时间测量、系统计量标定方法和系统软件等作了介绍。 相似文献
39.
Recent data and theory for type II solar radio bursts are reviewed, focusing on a recent analytic quantitative theory for
interplanetary type II bursts. The theory addresses electron reflection and acceleration at the type II shock, formation of
electron beams in the foreshock, and generation of Langmuir waves and the type II radiation there. The theory's predictions
as functions of the shock and plasma parameters are summarized and discussed in terms of space weather events. The theory
is consistent with available data, has explanations for radio-loud/quiet coronal mass ejections (CMEs) and why type IIs are
bursty, and can account for empirical correlations between type IIs, CMEs, and interplanetary disturbances.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
40.
Kamide Y. Kihn E.A. Ridley A.J. Cliver E.W. Kadowaki Y. 《Space Science Reviews》2003,107(1-2):307-316
We report the recent progress in our joint program of real-time mapping of ionospheric electric fields and currents and field-aligned
currents through the Geospace Environment Data Analysis System (GEDAS) at the Solar-Terrestrial Environment Laboratory and
similar computer systems in the world. Data from individual ground magnetometers as well as from the solar wind are collected
by these systems and are used as input for the KRM and AMIE magnetogram-inversion algorithms, which calculate the two-dimensional
distribution of the ionospheric parameters. One of the goals of this program is to specify the solar-terrestrial environment
in terms of ionospheric processes, providing the scientific community with more than what geomagnetic activity indices and
statistical models provide.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献