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1.
The chemical compositions of the atmospheres of six metal-poor stars are analyzed. Spectra with signal-to-noise ratios of no less than 100 and a resolution of R≈17 000 were obtained using the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. The abundances of Li, O, α-process elements (Mg, Si, Ca, Ti), Na, K, Sc, iron-peak elements (Cr, Mn, Fe, Ni, Cu, Zn), and s-process elements (Y, Ba) are derived. The star G251-54 ([Fe/H]=?1.55, T eff=5541 K, logg=3.58) is deficient in some elements compared to both stars with similar metallicities and the Sun. The atmosphere of G251-54 has the following elemental abundances relative to iron: [O/Fe]=+0.47, [α/Fe]≈?0.3, [Na/Fe]=?0.60, [Sc/Fe]=?0.57, [Cr, Ni, Fe]≈0, [Zn/Fe]=+0.16, [Cu/Fe]=?0.66, [Y/Fe]=?0.70, and [Ba/Fe]=?1.35. The remaining five stars have metallicities in the range ?1.6<[Fe/H]相似文献
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V. V. Ermakov S. F. Tyutikov A. P. Degtyarev V. A. Safonov V. N. Danilova S. D. Khushvakhtova U. A. Gulyaeva E. V. Krechetova 《Geochemistry International》2018,56(4):318-331
Specific responses of plants and animals to changes in the contents of microelements (Pb, Cd, Cu, Zn, As, Se, etc.) in abiotic environmental components of the Ardon River Basin (North Ossetia) were studied by new biogeochemical indication methods. In comparison to background areas, a local increase in the Pb, Cd, Cu, Zn, and As contents in soils and organisms occurs under the impact of natural and technogenic factors. The heavy metal contents in Ardon River water are generally within hygienic norms. Activation of sulfurcontaining synthesis in the leaves of willow, sea buckthorn, and coltsfoot was revealed for the maximum heavy metal content in soils. On plots adjacent to the Unal tailing dump, the contents of pigments and their proportions in leaves of coltsfoot, dandelion, and willow do not differ from those in less contaminated areas. On technogenic plots, the species richness of plants decreases, as well as the mowed biomass and projective cover of herbaceous plants (to 40%); inhibition of plant growth, chlorosis, necrosis, and lamina deformation are observed. A new metallophyte species (Cladochaeta candidissima M. Bieb.) was revealed. The increase in lead and arsenic contents in soils and plants of the Ardon floodplain is accompanied by an increase in their concentrations in the blood and hair of animals. 相似文献
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E. E. Grigorenko S. D. Shuvalov H. V. Malova V. Yu. Popov V. N. Ermakov E. Dubinin L. M. Zelenyi 《Solar System Research》2017,51(5):347-361
During the last 15 years, the Current Sheets (CSs) have been intensively studied in the tail of the terrestrial magnetosphere, where protons are the dominated ion component. On the contrary, in the Martian magnetotail heavy ions (O+ and+ 0) usually dominate while the abundance of protons can be negligible. Hence it is interesting to study the spatial structure and plasma characteristics of such “oxygen” CSs. MAVEN spacecraft (s/c) currently operating on the Martian orbit with a unique set of scientific instruments allows observation of the magnetic field and three-dimensional distribution functions of various ion components and electrons with a high time resolution. In this paper, we analyse nine intervals of the CSs observed by MAVEN in the near-Mars tail at the distances from the planet ~1.5–1R M , where R M is the radius of Mars. We analyse the spatial structure of the CSs and estimate their thickness for different magnetic configurations and relative abundance of the heavy and light ions in the sheets. It is shown that, similarly to the CSs in the Earth’s magnetotail, the thickness and complexity of the spatial structure of the Maritan CSs (i.e. the presence of embedded and / or peripheral current structures) depend on the magnetic configuration of the sheets, which, in turn, affects the fraction of the quasi-adiabatic particles in the CSs. 相似文献
4.
We studied the time dynamics of a turbulent region excited by a moving surface vessel in a field experiment. The time dependences
of the geometrical sizes of the turbulent region are obtained, and it is shown that the time dependence of the width of the
turbulent wake at the initial stage is close to the power-law function with an exponent of 0.4 for different experiments (the
depth of the wake remaining practically constant). In the semiempirical turbulence theory, we suggested a qualitative model
describing the process of the initial expansion of a ship wake as a diffusion of a one-dimensional layer of turbulized liquid
due to a pulsed source. 相似文献
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D. M. Ermakov E. A. Sharkov I. V. Pokrovskaya A. P. Chernushich 《Izvestiya Atmospheric and Oceanic Physics》2013,49(9):974-985
The trajectory characteristics and the intensity evolution of the Alberto tropical cyclone (TC) in the integral water-vapor field are analyzed in detail using a software-algorithmic complex designed for constructing highly detailed global radio-thermal fields of the ocean-atmosphere system based on microwave satellite measurements. This complex was developed by the authors earlier and allows one to obtain global animated radio-thermal fields with a time step of 1.5 h and a spatial resolution of 0.2°. Special attention is paid to the problem of revealing the energy sources of three consecutive intensifications of this TC. The analysis of satellite data with the use of the animation method developed by the authors shows for the first time that these sources are regions with an increased (exceeding the critical level) integral water-vapor content located in different geographical areas lying along the complex trajectory of the TC with a variable intensity. The first region was located in the equatorial intertropical convergence zone, the second was located above the Gulf Stream water area, and the third resided in the area affected by the Azores High. 相似文献
8.
Geological interpretation of seismic sections calculated using modern methods of processing data of deep seismic sounding
of the 1960s was carried out. Images and quantitative characteristics of rift structures around Andrusov ridge and elements
of the subduction zone in the southern frame of the Skiff plate were obtained. The location of structures in plan was determined. 相似文献
9.
A. V. Ermakov 《Journal of Volcanology and Seismology》2008,2(4):248-261
Supposing a leading role of free heat convection in the hydrothermal system above the magma chamber, a model of the hydrothermal system of the Akademii Nauk caldera in Kamchatka is suggested. The model is based on available geological, hydrogeological and geothermal data for the area. Three possible variants of the model are discussed. Based on temperature distribution data, the variant best corresponding to the natural conditions has been chosen. The period of hydrothermal system stabilization for all the variants is close to 7000–8000 years. 相似文献
10.
O. S. Ermakova S. A. Ermakov Yu. I. Troitskaya 《Izvestiya Atmospheric and Oceanic Physics》2007,43(1):86-94
The evolution of a turbulent layer excited by standing surface parametric waves is studied experimentally. The time dependence of the depth of the turbulized region is obtained. It is found that the thikness of the layer is described by a nonlinear dependence as distinguished from the previously obtained theoretical results. The dynamics of turbulent-layer embedding is described on the basis of a semiempirical theory and the assumption that the outer scale of turbulence is constant. Satisfactory agreement with experimental data is obtained. In the context of the proposed model, a relationship is found between the quantities characterizing the turbulence and surface waves. The dependence of the steepness of surface waves on the acceleration of the bottom is obtained experimentally. The data obtained in this study can be used for estimation of turbulence generation during a submarine earthquake. 相似文献