排序方式： 共有38条查询结果，搜索用时 15 毫秒
31.
V. A. Hagen-Thorn V. M. Larionov D. A. Blinov A. A. Arkharov E. I. Hagen-Thorn E. V. Borisova L. O. Takalo A. Sillanpää 《Astronomy Reports》2013,57(10):726-733
Results are presented of multicolor observations of the blazar 3C 454.3 carried out at the Astronomical Institute of St. Petersburg State University and the Central Astronomical Observatory of the Russian Academy of Sciences in 2007–2010. The color variability of the blazar is analyzed. Several outbursts were observed. The existence of two variable synchrotron sources is inferred. The first is responsible for the small-amplitude flux variability, and the second for flares. In each flare, the relative spectral energy distribution (SED) of the variable source is found to be constant. All the SEDs are power laws, but with different spectral indexes in different flares. This indicates the impossibility of explaining the global variability only via a difference in Doppler boosting due to variations of the angle between the line of sight and the velocity of the electrons responsible for the synchrotron radiation. The polarimetric and photometric observations are used to derive the absolute SED of constant component. A comparison of the observed SEDs for different brightness levels with the SED of the constant componentmakes it possible to explain the observed color variability as due to the superposition of a bluer variable source with a constant SED and variable flux onto the constant component. 相似文献
32.
This paper, the third in a series on the design, payloads, and operation of Soviet earth resource observation satellites [see MSRS, 1984, No. 4 and 1985, No. 1], describes the collection of supplemental sub-satellite information. More specifically, it outlines how the Soviets use satellite-synchronized aerial, ground, and water-borne sensors to gather auxiliary information used in the improvement of space imagery (data verification and correction, instrument calibration, etc.). A later section demonstrates procedures for selection and preparation of field test sites (for ground truth), and design of sub-satellite information measurement complexes. Translated from: Priroda Zemli iz kosmosa, A. P. Tishchenko and S. V. Viktorov, eds. Leningrad: Gidrometeoizdat, 1984, pp. 35-38. 相似文献
33.
34.
V. M. Ryzhkov V. N. Anfilogov I. A. Blinov A. A. Krasnobaev P. M. Valizer 《Doklady Earth Sciences》2016,469(2):824-827
The results of study of phase equilibria in the MgO–SiO2–ZrO2 system at 1450–1550°C are reported. The studied system contains two eutectic points and six fields: (I) MgSiO3 + SiO2; (II) MgSiO3 + ZrO2; (III) ZrSiO4 + SiO2; (IV) MgSiO3 + Mg2SiO4; (V) ZrO2 + MgO; (VI) ZrSiO4 + ZrO2. The presence of fields (II) and (III) on the diagram shows that zircon in equilibrium with olivine and pyroxene crystallizes at very low concentrations of ZrO2 in the system. This provides a solution for one of the most important problems in zirconology of dunites: the probability of the formation and preservation of zircon in the course of the formation and evolution of dunite. 相似文献
35.
The cosmic ray flux through the atmosphere at different levels of solar activity is simulated. The Geant program package has been used to determine the atmospheric zones where the maximal contrast of the released ray energy originates between the periods of solar minimum and maximum. The geographic coordinates and altitudes of these zones have been calculated. The results can be used to search for statistical correlations between the solar activity variations and dynamics of atmospheric transparency. 相似文献
36.
37.
38.
D. G. Zamolodchikov V. I. Grabovskii G. N. Korovin M. L. Gitarskii V. G. Blinov V. V. Dmitriev W. A. Kurz 《Russian Meteorology and Hydrology》2013,38(10):701-714
Considered are the contribution of managed forests in the Russian Federation to the climate change softening and the forecast of their carbon-depositing potential in the period till 2050 under different scenarios of the forest management. The sink of CO2 to managed forests is estimated using the flow balance method. The CBM-CFS3 model worked out in the Canadian Forestry Service is used for predicting the carbon budget. It is found out that managed forests absorb 473.8 Mt of CO2 per year. The carbon sink is caused by the reduction of the volume of the forest use and by the regeneration of cutover stands of previous years. Depending on the conditions of the forest use, by 2020 the CO2 sink to managed forests will amount to 466–632 Mt/year and will be able to compensate from 21 to 29% of industrial emissions of greenhouse gases. The carbon absorption by managed forests will decrease to 105–235 Mt/year by 2050. To maintain and increase the carbon-depositing potential of managed forests, the Russian Federation needs the development of the system of purposeful activities on strengthening the protection against forest fires and on the intensification of forest reproduction. 相似文献