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Based on our compiled catalogue of fundamental astrophysical parameters for 593 open clusters, we analyze the relations between the chemical composition, spatial positions, Galactic orbital elements, age, and other physical parameters of open star clusters. We show that the population of open clusters is heterogeneous and is divided into two groups differing by their mean parameters, properties, and origin. One group includes the Galactic clusters formed mainly from the interstellar matter of the thin disk with nearly solarmetallicities ([Fe/H] > ?0.2) and having almost circular orbits a short distance away from the Galactic plane, i.e., typical of the field stars of the Galactic thin disk. The second group includes the peculiar clusters formed through the interaction of extragalactic objects (such as high-velocity clouds, globular clusters, or dwarf galaxies) with the interstellar matter of the thin disk, which, as a result, derived abnormally low (for field thin-disk stars) metallicities and/or Galactic orbits typical of objects of the older Galactic subsystems. About 70% of the clusters older than 1Gyr have been found to be peculiar, suggesting a slower disruption of clusters with noncircular high orbits. Analysis of orbital elements has shown that the bulk of the clusters from both groups were formed within a Galactocentric radius of ??10.5 kpc and closer than ??180 pc from the Galactic plane, but owing to their high initial velocities, the peculiar clusters gradually took up the volumes occupied by the objects of the thick disk, the halo, and even the accreted halo of the Galaxy. Analysis of the relative abundances of magnesium (a representative of the ??-elements) in clusters that, according to their kinematical parameters, belong to different Galactic subsystems has shown that all clusters are composed of matter incorporating the interstellar matter of a single protogalactic cloud in different proportions, i.e., reprocessed in genetically related stars of the Galaxy. The [Mg/Fe] ratios for the clusters with thick-disk kinematics are, on average, overestimated, just as for the field stars of the socalled ??metal-rich wing?? of the thick disk. For the clusters with halo kinematics, these ratios exhibit a very large spread, suggesting that they were formed mainly from matter that experienced a history of chemical evolution different from the Galactic one. We point out that a large fraction of the open clusters with thindisk kinematics have also been formed from matter of an extragalactic nature within the last ??30 Myr. 相似文献
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A. R. Kotel’nikov V. I. Tikhomirova Z. A. Kotel’nikova N. I. Suk A. M. Koval’skii 《Geochemistry International》2009,47(6):568-577
S and Cl distribution between sodalite and fluid was experimentally studied at temperatures of 300–800°C and pressure of 0.5–3 kbar. It is demonstrated that S is preferably distributed into fluid in equilibrium with sodalite of the composition X S Sod > 0.05 throughout the whole temperature range. The distribution of S in the sodalite-fluid system is nonideal. An equation (derived from experimental data) is presented for evaluating the S mole fraction in fluid from the composition of sodalite at a known temperature. The S mole fractions in the fluid are evaluated for sodalite assemblages from nepheline syenites of the Lovozero Massif as being within the range of 0.036–0.23. The S mole fraction in the fluid is proved to increase with increasing mineral formation temperatures. 相似文献
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Modelling of rutting of two flexible pavements with the shakedown theory and the finite element method 总被引：1，自引：0，他引：1
Cyrille Chazallon Georg Koval Pierre Hornych Fatima Allou Saida Mouhoubi 《Computers and Geotechnics》2009
This paper presents a finite element program, for the modelling of rutting of flexible pavements. In its present version, the program incorporates a permanent deformation model for unbound granular materials based on the concept of the shakedown theory developed by Zarka for metallic structures under cyclic loadings and has been used to estimate the permanent deformations of unbound granular materials (UGM) subjected to traffic loading. The calculation is performed in two steps: the first step consists in modelling the resilient behaviour of the pavement in 3D, using non-linear elastic models, to determine the stress field in the pavement. Then stress paths are derived and used to calculate the permanent deformations and the displacements, using a Drucker–Prager yield surface. An application to the prediction of the permanent deformations of experimental pavements with an unbound granular base, tested on the LCPC pavement testing facility is presented. 相似文献
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M. M. Koval’chuk M. B. Hirnyak O. A. Baran M. I. Stodilka Ye. B. Vovchyk A. I. Bilinsky Ya. T. Blahodyr N. V. Virun S. V. Apunevych 《Kinematics and Physics of Celestial Bodies》2017,33(5):245-249
The influence of active processes on the Sun and their response on the dynamics of Earth’s artificial satellites has been investigated. The relationship between the characteristics of solar activity and variations of the periods P of the orbital motion of Earth’s artificial satellites has been found. These variations mainly indicate the variations in the Earth’s atmosphere density caused by solar activity (index F10.7) and geomagnetic activity (ΣKp index). High values of the correlation coefficients between P and F10.7 (–0.77…–0.91) and between P and ΣKp (–0.67…–0.89) exhibit significant effect of solar and geomagnetic activity on the orbital periods of satellites. 相似文献
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Babin A. N. Koval’ A. N. Tsap Yu. T. Borisenko A. V. 《Geomagnetism and Aeronomy》2018,58(8):1149-1158
This paper examines the evolution and morphology of a magnetic anomaly: the appearance and disappearance of a longitudinal magnetic flux with opposite polarity at an area of about 10 arc seconds in the umbra of the following sunspot of an NOAA 12192 active region, which was observed from 21 to 26 October 2014 in the SDO/HMI and SOLIS/VSM magnetograms. Information collected by spacecraft and under on-ground observations including data from the Sun Service of the Crimean Astrophysical Observatory of the Russian Academy of Sciences are analyzed. Based on the methods of observation and determination of longitudinal magnetic fields in SDO/HMI in line FeI 6173.34 Å it was revealed, that combinations of contours appearing due to magnetic force lines inclinations relative to the line-of-sight and line-of-sight velocities can cause a significant undervalue of the magnetic field intensity in magnetograms, but polarity does not reverse. The fine spatial structure, evolution features, close correlation with ultraviolet loops system in SDO/AIA images, “moustaches”, and no temporal and spatial correlation with flares point to a connection between the detected anomaly and the new magnetic flux emergence of opposite polarity in a spot’s umbra at an earlier decay stage. We analyze magnetic force lines reconnection and show that annigilation of the magnetic fields of opposite polarities can take place for many hours at small (~30 km) scales and this fact is verified by observation results. There are additional facts in favor of the cluster model of a solar spot by Severny-Parker.
相似文献27.
Water Resources - The results of long-term field studies are used to consider in detail the issues of hydrological regime formation in a lagoon–channel estuary of the Bol’shaya R. in... 相似文献
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A. V. Koval N. M. Gavrilov A. I. Pogoreltsev N. O. Shevchuk 《Geomagnetism and Aeronomy》2018,58(2):281-289
Numerical modeling of changes in the zonal circulation and amplitudes of stationary planetary waves are performed with an accounting for the impact of solar activity variations on the thermosphere. A thermospheric version of the Middle/Upper Atmosphere Model (MUAM) is used to calculate the circulation in the middle and upper atmosphere at altitudes up to 300 km from the Earth’s surface. Different values of the solar radio emission flux in the thermosphere are specified at a wavelength of 10.7 cm to take into account the solar activity variations. The ionospheric conductivities and their variations in latitude, longitude, and time are taken into account. The calculations are done for the January–February period and the conditions of low, medium, and high solar activity. It was shown that, during high-activity periods, the zonal wind velocities increases at altitudes exceeding 150 km and decreases in the lower layers. The amplitudes of planetary waves at high solar activity with respect to the altitude above 120 km or below 100 km, respectively, are smaller or larger than those at low activity. These differences correspond to the calculated changes in the refractive index of the atmosphere for stationary planetary waves and the Eliassen–Palm flux. Changes in the conditions for the propagation and reflection of stationary planetary waves in the thermosphere may influence the variations in their amplitudes and the atmospheric circulation, including the lower altitudes of the middle atmosphere. 相似文献
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