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781.
Y. Apalkov I. Lagunov S. Grebenev M. Pavlinsky R. Sunyaev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):273-276
During 1990–1991 more than two dozens of extragalactic objects were observed by X-ray instruments aboard the Granat satellite. Among them there were AGNs and Seyfert galaxies (NGC4151, NGC5548, MCG-30-15, IC4329 etc.), quasars (3C273, 3C390.3 etc.), radio galaxies (Cen A, M87 etc.) and clusters of galaxies (Virgo, Perseus, Coma etc.). We will discuss below the preliminary results obtained with the ART-P telescope during the observations of five sources: NGC4151, 3C273, Cen A and the galaxies M87 and NGC4388 on the Virgo cluster. 相似文献
782.
E. A. Gurtovenko R. I. Kostik A. Tlamicha R. Zerull Aert Schadee A. Mészáros Y. Néeman R. H. Giese A. T. Sinclair J. Kleczek E. A. Trendelenburg Wolfgang Hillebrandt L. Sehnal W. de Graaff C. Slottje T. Courvisier H. F. van Beek B. Baud C. de Jager J. M. A. Danby B. V. Somov J. Cassinelli F. Verbunt 《Space Science Reviews》1986,44(1-2):177-188
783.
Four bipolar-FET (field-effect transistor) combinational transistor configurations are compared from the application point of view. The configurations included are FET-Darlington (cascade), emitter-open switch (cascode), parallel configuration, and FET-gated bipolar transistors (FGT). 相似文献
784.
N. Kawashima S. Sasaki A. Ushikoshi Y. Yagi T. Obayashi O. Kaneko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):159-161
Electron beam experiments in space that have been done and planned in Japan are reviewed. 200eV, 1mA electron beam is emitted from a satellite and several types of wave excitation such as UHF and ωce have been observed. The satellite potential and the energy spectrum of returning electrons are measured by Langmuir probes and electrostatic energy analyser. In rocket experiments of K-10-11, K-10-12, K-9M-57, K-9M-58, K-9M-61 and K-9M-66, several types of electron guns were used whose power ranges from 1mW to 1KW. The rocket potential was measured by Langmuir probes and floating probes and optical line emission measurement and wave measurements were also done. The rocket potential was not so high as expected from the balance with ionospheric plasma but strongly affected by the plasma production by the emitted electron beam and return electrons. 相似文献
785.
This article briefly presents the historical background, as seen by ISRO and India, to the growing problem of space debris. It describes the technical aspects of ISRO's activities in the field of space debris, and the grey areas in technical understanding, which may impede legal discussions. Analysis of the cost and technical aspects of reorbiting satellites from geostationary Earth orbit (GEO) is detailed, since this is an important area for India and other developing countries. The article also briefly describes ISRO's views of the applicability and relevance of the existing space treaties to a possible future legal regime for space debris. Debates are currently taking place in the UN and other multilateral fora on the subject of space debris and the situation is dynamic. The main aim of this article is to inform readers of ISRO's and India's position in the UN on the subject of space debris, in terms of its technical, political and legal aspects. Certain issues of importance from the legal point of view, though not of immediate urgency, are also discussed. 相似文献
786.
Y Mogami S A Baba 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,21(8-9):1291-1300
A new model explaining the gravitactic behavior of Paramecium is derived on the basis of its mechanism of gravity sensing. Paramecium is know to have depolarizing mechanoreceptor ion channels in the anterior and hyperpolarizing channels in the posterior of the cell. This arrangement may lead to bidirectional changes of the membrane potential due to the selective deformation of the anterior and posterior cell membrane responding to the orientation of the cell with respect to the gravity vector; i.e., negative- and positive-going shifts of the potential due to the upward and downward orientation, respectively. The orientation dependent changes in membrane potential, in combination with the close coupling between the membrane potential and ciliary locomotor activity, may allow the changes in swimming direction along the otherwise simple helical swimming path in the following manner: an upward shift of the axis of helical swimming occurs by decreasing the pitch angle due to channel-dependent hyperpolarization in upward-orienting cells, and an upward shift of the swimming helix occurs by increasing the cell's pitch angle due to depolarization in downward-orienting cells. Computer simulation of the model demonstrated that the cell can swim upward along the "super-helical" trajectory consisting of a small helix winding helically along an axis parallel to the gravity vector. 相似文献
787.
V. V. Akimov V. G. Afanassyev I. D. Blokhintsev L. F. Kalinkin N. G. Leikov V. E. Nesterov A. M. Galper Y. V. Ozerov V. A. Rudko M. F. Runtso V. M. Zemskov M. I. Fradkin L. V. Kurnosova M. A. Russakovitch N. P. Topchiev E. I. Chuikin V. Y. Tugaenko M. Gros A. R. Bazer-Bachi J. -M. Lavigne J. -F. Olive 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):739-742
The Geminga light curve obtained with the “Gamma-1” telescope features two peaks separated by 0.5 ± 0.03 period. The light curve is pronounced for γ-quanta energies higher than 400 MeV. The pulsed flux upper limit (1σ) in the energy interval 50 – 300 MeV is 6·10−7 cm−2sec−1. For energies >300 MeV the pulsed component power law spectrum has an exponent 1.1 −0.3+1.1 and an integral flux (1.1±0.3)·10−6 cm−2sec−1. 相似文献
788.
G Reitz H Bucker R Facius G Horneck E H Graul H Berger W Ruther W Heinrich R Beaujean W Enge A M Alpatov I A Ushakov D A Zachvatkin YuAMesland 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1989,9(10):161-173
Eggs of Carausius morosus were exposed to spaceflight conditions in two spaceflight missions, the German 7 day Spacelab Mission D1 and the Soviet 12.56 day Biosatellite Mission "COSMOS 1887". During spaceflight the eggs continued their development. Eggs of five different ages representing different sensitivity to radiation and different capacity to regeneration were used to investigate the influence of cosmic radiation and/or microgravity on insect development. Using the Biostack concept--eggs in monolayers sandwiched between nuclear track detectors--and the 1 g reference centrifuge of BIORACK in D1 we were able to separate effects of heavy ions of the cosmic radiation from microgravity effects and also from combined effects of these two factors in space. After retrieval, hatching rates, embryonic and larval growth kinetics and anomaly frequencies were determined. Microgravity leads to a reduced hatching rate of eggs exposed in the early stages of development. Hatching was normal in eggs which were exposed on the 1 g reference centrifuge. Hits by heavy ions caused body anomalies. The combined action of heavy ions and microgravity resulted in an unexpectedly high frequency of anomalies. These results obtained from the Spacelab Mission D1, were confirmed in an experiment onboard of COSMOS 1887. In addition to the previous analysis, embryonic development before hatching was followed which showed no major difference between flight and the ground control specimens. Since a reconfirmation of reduced hatching rates was observed in COSMOS 1887, too, the above results suggest some microgravity induced functional impairment of the hatching activity, rather than blockage in embryonic development. 相似文献
789.
Stable isotope analysis at the molecular level: a new approach for determining the origins of amino acids in the Murchison meteorite. 总被引:2,自引:0,他引:2
M H Engel S A Macko Y Qian J A Silfer 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1995,15(3):99-106
A combined gas chromatography/isotope ratio mass spectrometry (GC/IRMS) method has been developed that permits the direct stable carbon isotope analysis of N(O)-trifluoroacetyl-isopropyl esters of individual amino acids and their respective enantiomers at nanomole abundances. Calculation of the original delta 13C values of the amino acids is accomplished via a correction for the carbon introduced during the derivatization process. Previous GC/IRMS analyses of individual amino acids in the non-hydrolyzed water extract of an interior sample of a Murchison meteorite stone revealed an enrichment in 13C relative to terrestrial organic matter, in agreement with previous findings for bulk extracts. The range of amino acid delta 13C values (+5 to +30%, PDB) suggests possible kinetic effects during synthesis. In this study, an apparent kinetic isotope effect was also observed for the amino acid products of a spark discharge experiment. These preliminary results are supportive of a similar mechanism for the abiotic synthesis of amino acids in the Murchison meteorite. 相似文献
790.
W.Q. Gan Y.P. Li X.X. Yu L. Feng 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2003,32(12):2471-2476
The M4.0/SF flare on 17 March 2002 is a good example of the early observations with RHESSI. We presenthard X-ray images, light curves and energy spectra of individual hard X-ray sources, the spatial relationship between the hard X-ray sources and the H emission regions, and comparisons of light curves observed by RHESSI and GOES. We found that the picture exhibited by RHESSI is consistent with the general cartoon of a solar flare. In particular, we showed that the hard X-ray image spectra could be explained by a power-law electron beam with a lower energy cutoff Ec. The derived Ec could be as high as 40 keV, larger than the usually value of 20 keV. 相似文献