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961.
J.M. Bosqued C. Maurel H. Rème J.A. Sauvaud R.A. Kovrazhkin Yu.I. Galperin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(4):135-138
We present a detailed study of the distribution and of the internal structure of the inverted-V electron precipitation commonly detected in the 500 – 2000 km altitude range aboard the AUREOL-3 satellite. These structured precipitations are statistically observed inside the auroral oval with a maximum occurence in the nightside sector. They correspond to primary electron fluxes peaked at energies generally below 10 keV. It is shown that, as predicted by kinetic theories, most inverted-V structures present a clear relationship between the field-aligned current density carried by the 1 – 20 keV primary electrons and the potential drop inferred from particle distribution functions. Furthermore the study demonstrates the existence of strong electron heating, related to the energy gain, when the current density exceeds some threshold of about 1 – 5 μA(m)?2. 相似文献
962.
V I Trofimov A Victorov M Ivanov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(1-2):333-337
Two tasks must be accomplished to provide planetary protection for Mars return missions: (1) sterilization of the scientific module to be landed on Mars and (2) reliable sterilization of all material returned to Earth, while ensuring the scientific integrity of martian samples. This paper examines similarity and differences between these two tasks, and includes a discussion of technological implementation conditions and the nature of terrestrial and hypothesized martian microflora. The feasibility of a number of chemical and physical (ultraviolet and ionizing radiation and heating) methods of sterilization for use on the ground and onboard are discussed and compared. A combination of different methods will probably be selected as the most appropriate for ensuring planetary protection on the return mission. 相似文献
963.
964.
The magnetizing inductance of the isolated Cuk converter introduces an undesirable pair of closely spaced complex zeros and poles, or a glitch, in the control-to-output transfer function. Limited analysis and experimentation in the past have shown that sufficient increase in the magnetizing inductance or manipulation of the ratio of the capacitances of the energy transfer capacitors can reduce the glitch. In this work, the isolated Cuk converter with coupled input and output inductors has been studied and the dependence of the glitch on various circuit parameters has been determined analytically. A condition has been derived for the ratio of the capacitances of the two energy transfer capacitors which completely eliminates the glitch at a given operating point. With this condition satisfied, it is shown that the energy transfer capacitors can be easily damped by a simple RC network to eliminate the glitch from a wide range of operation about an operating point 相似文献
965.
A Tani M Kiyota I Aiga K Nitta Y Tako A Ashida K Otsubo T Saito 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(4-5):181-188
Trace contaminants generated in closed facilities can cause abnormal plant growth. We present measurement data of trace contaminants released from soils, plants, and construction materials. We mainly used two closed chambers, a Closed-type Plant and Mushroom Cultivation Chamber (PMCC) and Closed-type Plant Cultivation Equipment (CPCE). Although trace gas budgets from soils obtained in this experiment are only one example, the results indicate that the budgets of trace gases, as well as CO2 and O2, change greatly with the degree of soil maturation and are dependent on the kind of substances in the soil. Both in the PMCC and in the CPCE, trace gases such as dioctyl phthalate (DOP), dibutyl phthalate (DBP), toluene and xylene were detected. These gases seemed to be released from various materials used in the construction of these chambers. The degree of increase in these trace gas levels was dependent on the relationship between chamber capacity and plant quantity. Results of trace gas measurement in the PMCC, in which lettuce and shiitake mushroom were cultivated, showed that ethylene was released both from lettuce and from the mushroom culture bed. The release rates were about 90 ng bed-1 h-1 for the shiitake mushroom culture bed (volume is 1700 cm3) and 4.1 approximately 17.3 ng dm-2 h-1 (leaf area basis) for lettuce. Higher ethylene release rates per plant and per unit leaf area were observed in mature plants than in young plants. 相似文献
966.
A brief review of publications on the problem of two fixed centers is given, including its generalizations and astronomical applications. A comparison of the Darboux potential with that of Eve Gredeaks is made. An account of the basic points of development of modern high-precision theories of the motion of planetary satellites, based on the Gredeaks’ intermediate orbit, is given.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 3, 2005, pp. 194–200.Original Russian Text Copyright © 2005 by Lukyanov, Emeljanov, Shirmin.Dedicated to the memory of Professor Evgenii Petrovich Aksenov 相似文献
967.
I V Getselev P P Ignatiev N A Kabashova N N Kontor A R Moszhukhina G A Timofeev T G Khotilovskaya 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1992,12(2-3):441-444
Based on the available measurement data, simulations of radiation conditions during spacecraft flights in the interplanetary space and in the Earth's and Jupiter's radiation belts has been carried out. The > or = 10 MeV and > or = 30 MeV solar flare proton fluence forecast has been proposed for Cycle 22. Radiation conditions due to both magnetospheric electrons and protons and to solar flare protons, magnetic rigidity cutoff being taken into account, have been evaluated on spacecraft trajectories in the Earth's and Jupiter's magnetospheres. 相似文献
968.
B. Cordier F. Lebrun F. Mirable J. Paul P. Mandrou L. Bouchet J. P. Rogues G. Vedrenne R. Sunyaev E. Churazov M. Gilfanov N. Khavenson A. Dyachkov B. Novikov R. Kremnev V. Kovtunenko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):611-616
After more than two years of successful in-orbit operations, the γ-ray coded aperture SIGMA telescope has accumulated 800 hours of live-time observations of the Galactic Center region, including the remarkable hard source identified with the X-ray source 1E 1740.7–2942. The long-term behavior of the soft γ-ray emission of 1E 1740.7–2942, as determined from the SIGMA survey, supplemented with previously available soft γ-ray data, leads to its identification with a singular radio source, which consists of a double sided radio jet emanating from a compact variable core whose variability is correlated with that of the soft γ-ray source. The compact radio core, which lies well inside the improved soft γ-ray (40–150 keV) error circle (27″ radius) derived from the high-resolution SIGMA survey, is also inside the ROSAT and TTM error circle derived respectively in the soft and hard X-ray bands. 相似文献
969.
970.
A generalized small-signal analysis approach that is based on both the Taylor's series expansion and the state-plane diagram is presented. A generalized discrete small-signal model for a double-ended DC-to-DC resonant converter operating in the continuous conduction mode is also given. Based on the model derived, the frequency responses for two transfer functions, namely, the line-to-output and the control-to-output transfer functions, are obtained. The technique is verified by applying it to the conventional series resonant converter whose small-signal analysis is known 相似文献