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1.
M. A. Vashkov’yak 《Astronomy Letters》2001,27(7):464-469
We consider the structural peculiarities of Uranus’s satellite system associated with its separation into two groups: inner equatorial satellites moving in nearly circular orbits and distant irregular satellites with retrograde motion in highly elliptical orbits. The intermediate region is free from satellites in a wide range of semimajor axes. By analyzing the evolution of satellite orbits under the combined effect of solar attraction and Uranus’s oblateness, we offer a celestial-mechanical explanation for the absence of equatorial satellites in this region. M.L. Lidov’s studies during 1961–1963 have served as a basis for our analysis. 相似文献
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This review is devoted to problems in the photochemical modeling of atmospheric processes. The physicochemical and mathematical foundations underlying the construction of photochemical models are described, a classification of the atmospheric reactions is presented, and the features of photochemical modeling are considered under various irradiance conditions for various atmospheric layers and geographical regions. Atmospheric processes that are important to photochemical models are discussed. Applications involving photochemical models are outlined. Some results are presented to illustrate the capabilities of photochemical models. Special attention is given to relatively recent directions in photochemical modeling, such as data assimilation and inverse problems. The review can be used by experts in areas related to atmospheric chemistry as a basic source of knowledge on the subject and for the development of photochemical modules for atmospheric models. 相似文献
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The tectonic evolution of the Por’ya Guba segment of the White Sea Rift System began in the late Paleoproterozoic, i.e., soon
after completion of the Svecofennian collision. The fracture system that controlled localization of the lamproite dike complex
was formed under conditions of horizontal compression combined with shear. Subsequently, this system predetermined the location
of a rift-graben segment that formed as a result of simple shear. The reactivation of the rift system in the Middle Paleozoic
proceeded in two stages. The first stage, when strike-slip movements along previously formed faults predominated, resulted
in formation of quartz-carbonate veins bearing base-metal mineralization. The veins that filled the shear fractures opened
owing to local reorientation of the stress field. The second stage fitted the transtension conditions, and the Late Devonian
alkaline ultramafic dikes of this stage introded into the already existing fracture system, which was oriented at a roughly
right angle to the predominant stress orientation. 相似文献
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We have mapped three star-forming regions (G265.14+1.45, G269.16?1.14, G291.27?0.71) in the CS(3–2) and C34S(2–1) lines using the 15 m SEST telescope (Chile), and analyzed the relative positions of methanol and H2O masers, IRAS sources, and emission maxima in the CS lines. In most cases, the maser positions are close to those of the IRAS sources. We compared the radial velocities of the maser sources and high-density CS cores, and estimated the CS column densities assuming LTE. The sizes, densities, and masses of the dense core are estimated; the masses obtained in the LTE approximation agree with the virial masses. 相似文献