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81.
    
  相似文献   
82.
Mercury has a small but intriguing magnetosphere. In this brief review, we discuss some similarities and differences between Mercury’s and Earth’s magnetospheres. In particular, we discuss how electric and magnetic field measurements can be used as a diagnostic tool to improve our understanding of the dynamics of Mercury’s magnetosphere. These points are of interest to the upcoming ESA-JAXA BepiColombo mission to Mercury.  相似文献   
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84.
    
The space shuttle external tank, which consists of a liquid oxygen tank, an intertank structure, and a liquid hydrogen tank, is an expendable structure used for approximately 8.5 min during each launch. A concept for outfitting the liquid oxygen tank-intertank unit for a 12-person lunar habitat is described. The concept utilizes existing structures and openings for both man and equipment access without compromising the structural integrity of the tank. Living quarters, instrumentation, environmental control and life support, thermal control, and propulsion systems are installed at Space Station Freedom. The unmanned habitat is then transported to low lunar orbit and autonomously soft landed on the lunar surface. Design studies indicate that this concept is feasible by the year 2000 with concurrent development of a space transfer vehicle and manned cargo lander for crew changeover and resupply.  相似文献   
85.
Since 1986, a series of microcosm experiments has been conducted at the Unit of Comparative Plant Ecology (UCPE) in an attempt to test our understanding of the principles controlling the structure and dynamics of plant communities and ecosystems. In each experiment microcosms have been seeded with a common pool of organisms, and systems have been allowed to assemble under replicated controlled conditions. Experiment variables have included mineral nutrient supply, temperature, moisture supply, soil depth, carbon dioxide concentration, mycorrhizas, rhizobia, herbivores and carnivores. Results from these experiments are presented to illustrate the value of synthesised ecosystems in ecological research.  相似文献   
86.
This paper analyzes the accuracy of orbit determination calculated by observations of short arcs. In this case, we imposed the condition that the arc length and/or the distribution of arc observations should provide a confident classification of the orbit of a small celestial body allowing one to distinguish a potentially hazardous body, also including a threat of collision.  相似文献   
87.
    
Several years of hourly daily GPS measurements of the vertical total electron content (TEC) and of the equivalent slab thickness made at different European locations are analysed by using the linear regression technique to demonstrate the response of these two ionospheric parameters to seasonal variations. It is found that both TEC and slab thickness are highly correlated with season. Analytical relationships are determined expressing the seasonal dependence of the vertical TEC and of the equivalent slab thickness as a function of the seasonal parameter cos χ at noon in each location.  相似文献   
88.
Active detectors used as radiation monitors in space are not usually able to perform Particle Identification (PID). Common techniques need energy loss spectra with high statistics to estimate ion abundances. The ALTEA-space detector system is a set of silicon strip particle telescopes monitoring the radiation environment on board the International Space Station since July 2006 with real-time telemetry capabilities. Its large geometrical factor due to the concurrent use of six detectors permits the acquisition of good energy loss spectra even in a short period of observation. In this paper we present a novel Fast Probabilistic Particle Identification (FPPI) algorithm developed for the ALTEA data analysis in order to perform nuclear identification with low statistics and, with some limitations, also in real time.  相似文献   
89.
    
Lyubimov  G. P.  Tulupov  V. I. 《Cosmic Research》2003,41(1):19-27
The enhancements of solar protons with an energy of more than 30 MeV, originating from flares in one active region and observed simultaneously aboard three spacecraft Vega-1, 2 and Prognoz-10 in July 1985, are analyzed and approximated in this work by using the reflection model [2]. The numerical values of several physical parameters (the parameters of distribution of solar cosmic ray (SCR) particles inside heliosphere traps, the coefficients of trap transparency) that are not observed by direct measurements are estimated.  相似文献   
90.
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