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61.
M. I. Verigin G. A. Kotova V. V. Bezrukikh V. V. Bogdanov A. V. Kaisin 《Geomagnetism and Aeronomy》2011,51(1):39-48
Based on the thermal plasma measurements in the Earth’s inner plasmasphere on the INTER-BALL-2 and MAGION-5 satellites it
has been indicated that the plasmaspheric ion temperature as a rule decreases during the main phase of magnetic storms; in
this case the plasma density increases or remains at the level typical of undisturbed conditions. The physical mechanism by
which the ion drift during a magnetic storm results in a temperature decrease is described. It is shown that the third adiabatic
invariant also remains in processes with a characteristic time shorter than the period of charged particle drift around the
Earth for cold equatorial plasma. The constructed model of the drift shell displacement from the Earth caused by a decrease
in the magnetic field in the inner magnetosphere during the development of a magnetic storm satisfactorily describes the decrease
in the proton temperature near the equatorial plane. 相似文献
62.
Based on 148 analyses, we report the petrochemical characteristics of Riphean and Vendian coarse-grained sedimentary rocks of the Uchur–Maya region in eastern Siberia, which is referred to the Proterozoic continental-margin domain. Various methods of petrochemical study applied to Precambrian sandstones are examined. Normative mineral compositions of specific groups of arenites, particularly basal potassic arkoses, are considered. Differences in sandstone compositions at certain stratigraphic levels are shown, and the evolution of chemical composition of rocks is traced through sections of sedimentary cover (Maya Plate) and margin region (Yudoma–Maya Trough). The work presents results of the application of data on mineralogical and chemical compositions of arenites for the restoration of paleodynamic environments in Late Proterozoic sedimentation basins at the southeastern margin of the Siberian Platform. 相似文献
63.
Evolution of a large-scale river plume is studied numerically using the Massachusetts Institute of Technology general circulation model. The model parameters were set close to those observed in the area of the Columbia River mouth. The fine-resolution grid along with the non-hydrostatic dispersion included in the model allowed for the reproduction of detailed inner plume structure, as well as a system of internal waves radiated from the plume’s boundary. It was found that not only first-mode but also second- and third-mode internal waves are radiated from the plume at the latest stages of its relaxation when the velocity of the front propagation drops below an appropriate wave phase speed of internal baroclinic mode. The model output shows that the amplitude of these high-mode waves is of the same order as the leading first-mode waves, which in combination with the specific vertical structure (location of the maximum structure function beyond the pycnocline layer) creates favourable conditions for the generation of shear instabilities. High-resolution model output also reveals evidence of a fine internal structure of the plume characterized by the presence of secondary fronts inside the plume and secondary internal wave systems propagated radially from the lift-off area to the outer boundary. These structures intensify the mixing processes within the propagating plume with predominance of the entrainment mechanism developing on the lower boundary between the plume’s body and underlying waters. The scheme of horizontal circulation in the plume was reproduced by the methodology of Lagrange drifters released near the mouth at different depths.
相似文献64.
Oksana Sytar Marian Brestic Abhay Kumar M. N. V. Prasad Nataliya Taran Iryna Smetanska 《洁净——土壤、空气、水》2013,41(11):1129-1137
In this study, Fagopyrum esculentum (common buckwheat) sprayed with nickel (Ni) (0, 0.5, 1.0, 3.0, and 5.0 mM) for different duration has been investigated for Ni accumulation, malondialdehyde (MDA), total phenolics, and phenolic acids. Ni accumulation significantly increased in dose‐dependent manner. Plants exposed for 72 h, showed visible damages as chlorosis and irreversible necrosis. The MDA and total phenolic contents increased at 24 h of Ni treatments. HPLC data revealed that phenolic acids are in good correlation with concentration and durations of treatments. After 24 and 48 h the contents of chlorogenic, p‐hydroxybenzoic, hesperetic, p‐anisic, and caffeic acids increased in Ni treated leaves. On the other hand, p‐hydroxybenzoic, hesperetic, p‐anisic, p‐coumaric, caffeic acids contents decreased after 72 h of Ni exposure. Vanillic and cinnamic acid followed same pattern and increased significantly at 3.0 and 5.0 mM after 48 h of Ni exposure. It may suggest that buckwheat can be possible hyperaccumulators of Ni, because of high Ni accumulation in tissues through foliar treatment. Furthermore, the analyzed phenolic acids have potential role as antioxidants, which provide tolerance to buckwheat against Ni treatment. 相似文献
65.
V. N. Podkovyrov L. N. Kotova A. B. Kotov V. P. Kovach O. V. Graunov N. Yu. Zagornaya 《Stratigraphy and Geological Correlation》2007,15(1):41-56
As is shown based on geochemical data and Sm-Nd isotopic systematics, accumulation of sandy deposits in the Riphean protoplatform cover of the Southeast Siberian platform was controlled by influx of primary and recycled sedimentary material derived from magmatic and metamorphic complexes of the eastern Aldan shield in the course of denudation of the Early Proterozoic accretionary orogen formed prior to 1.9 Ga. First indications of endogenic material influx into sedimentary basins are established in the Totta Formation of the Middle Riphean. They mean contribution to sedimentation of material weathered and eroded from external recycled orogens and synsedimentary volcanics that marked commencement of rifting in the platform marginal zone. Provenances of this material were situated most likely to the east and southeast off the Yudoma-Maya trough. 相似文献
66.
A. E. Stepanov V. L. Khalipov G. A. Kotova M. S. Zabolotskii I. A. Golikov 《Geomagnetism and Aeronomy》2016,56(2):181-186
The data of the ionospheric observations (the daily f plots) at the Yakutsk meridional chain of ionosondes (Yakutsk–Zhigansk–Batagai–Tixie Bay) with sharp decreases (breaks) in the critical frequency of the regular ionospheric F2 layer (foF2) are considered. The data for 1968–1983 were analyzed, and the statistics of the foF2 break observations, which indicate that these breaks are mainly registered in equinoctial months and in afternoon and evening hours under moderately disturbed geomagnetic conditions, are presented. Calculations performed using the prognostic model of the high-latitude ionosphere indicate that the critical frequency break position coincides with the equatorial boundary of large-scale plasma convection in the dusk MLT sector. 相似文献
67.
E. V. Lukyanova N. N. Akinfiev A. V. Zotov I. T. Rass N. P. Kotova V. S. Korzhinskaya 《Geology of Ore Deposits》2017,59(4):305-314
Available experimental data on the solubility of Nb2O5 and the stability constants for particles of an aqueous solution in the Nb–O–H–F system were processed. As a result, a set of thermodynamic properties for 25°C and 1 bar was obtained, in addition to the equation parameters for the HKF model (Helgeson–Kirkham–Flowers) for hydroxo and hydroxofluoride niobium complexes. F– ion is the most important factor governing the concentration of dissolved Nb: neutral hydroxo complex Nb(OH)5(aq) is formed at a low HF concentration, whereas an increase in HF results in an increase in the first Nb(OH)4F(aq) and second Nb(OH)3F2(aq) fluoride complexes. The Nb(OH)5F– oxofluoride anion determines oxide solubility in alkali F-bearing fluids. Neutralization of acidic fluoride solution can be the main factor leading to niobium deposition. 相似文献
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69.
Sulfide-mineral-bearing mill wastes are sources of high concentrations of acid, soluble metals, and As. These are serious problems for ore mining areas such as the Kemerovo and Cheljabinsk regions in Russia. This study evaluated the distribution of the mill wastes, the mobility of As from the wastes, and the potential of natural materials to attenuate As dispersion in the broader environment. Arsenic contents in wastes of the Belovo Zn-processing (Kemerovo) and the Karabash Cu-smelting plants (Cheljabinsk) are 2–3 orders of magnitude higher than the content of continental crust. Main mineral forms of As in these wastes are arsenopyrite (FeAsS) and scorodite (FeAsO4·2H2O). High dissolved As concentrations are found in water draining the wastes and in rivers adjacent to the mill sites. The water concentrations commonly exceed drinking water standards. High As concentrations in bottom sediments of the affected rivers extend a 100 m downstream of the waste drainage input. These sediments are also a source of river water contamination. Experiments were conducted to evaluate the ability of natural water to mobilize As from the wastes. The Belovo tailings released 86% of their contained As to the infiltrating water, whereas the less reactive Karabash tailings released only 22% of total As. The experimental leachates were used as influent to columns that tested the ability of limestone and natural clay to reduce the concentration of dissolved As and associated metals. Some dissolved As was precipitated with Fe, Pb and Sb initially in the limestone column. The decrease in dissolved As is consistent with the accumulation of As in yellow ferriferous sediments in the Belovo settling pond. In the pond and wetland sediments, As mobility is also decreased by the formation of sulfides and arsenides. Cubanite (CuFe2S3), klaprothite (Cu3BiS3), rammelsbergite (NiAs2), maucherite (Ni11As8), semseyite (Cu9Sb8S21), and skutterudite (CoAs3) were found in the chemically reducing lower sediments of the Belovo settling pond. 相似文献
70.