The Herbig Ae star V 517 Cyg     

G. V. Abramyan  S. V. Zaratsyan  N. D. Melikyan  S. Yu. Mel'nikov  V. S. Shevchenko 《Astrophysics》1990,32(1):24-29

Byurakan Astrophysical Observatory, Armenian Academy of Sciences; Astronomical Institute, Uzbek Academy of Sciences. Translated from Astrofizika, Vol. 32, No. 1, pp. 39–47, January–February, 1990.  相似文献   

Distribution of Heavy Metals in Gray Silts in the Volga Cascade of Reservoirs     

Maslov  A. V.  Nemirovskaya  I. A.  Shevchenko  V. P. 《Water Resources》2021,48(6):977-990

Water Resources - The concentrations of heavy metals in gray silts were analyzed in the Volga cascade of Reservoirs (June 2016, R/V Akademik Topchiev, Borok Village–Astrakhan City). The mean...  相似文献   

New data on the age of dolerites and basalts of Mendeleev Rise (Arctic Ocean)     

V. A. Vernikovsky  A. F. Morozov  O. V. Petrov  A. V. Travin  S. N. Kashubin  S. P. Shokal’sky  S. S. Shevchenko  E. O. Petrov 《Doklady Earth Sciences》2014,454(2):97-101

We present results of ⁴⁰Ar/³⁹Ar isotopic investigations concerning the dating of dolerites and basalts that were sampled during the Arctica-2012 polar expedition. Basalts were sampled by means of deep underwater drilling with wells up to 2 m in outcrops on the seafloor (basalts), and dolerite samples were obtained from the bottom of an escarp of Mendeleev Rise using a manipulator on the research submarine. The analysis results of the obtained mono-mineral fractions (amphibole, plagioclase, pyroxene) from the studied rocks yielded an Early Paleozoic age of the dolerites and basalts from Mendeleev Rise. The oldest ages obtained for amphibole reach 471.5 ± 18.1 and 466.9 ± 3.3 Ma, which corresponds to the Early-Middle Ordovician. The isotopic composition of argon was measured on two mass spectrometers: the Micromass Noble Gas 5400 (UK) and the Thermo Scientific Argus (Germany). The determined Early Paleozoic age of igneous rocks of Mendeleev Rise and seismic data obtained during the last Russian expedition Arctica-2012 [2] let us suppose that this continental block of the Earth’s crust has a Precambrian basement similar to the basement identified for the New Siberian islands including the De Long archipelago.  相似文献   

Stability of the multiple star system ι UMa (ADS 7114)     

A. V. Mel’nikov  V. V. Orlov  I. I. Shevchenko 《Astronomy Reports》2014,58(9):640-649

The physical and orbital parameters of the quadruple star system ι UMa (HD 76644 = ADS 7114) were determined earlier, when it was concluded based on modeling the system’s dynamics and applying theoretical stability criteria that the system was probably unstable. Here the stability of the ι UMa system is studied by calculating the Lyapunov characteristic exponents for representative sets of parameters and initial conditions. The conclusions on the system’s stability (or instability) based on various stability criteria and the calculated Lyapunov exponents are compared. The instability of the system as a whole is confirmed rigorously based on massive computations of the Lyapunov exponents. This system appears to be the only known multiple system whose instability has been rigorously established. The Lyapunov time-disruption time statistical relations are constructed, which show that the Hamiltonian intermittency of the second kind dominates. Typical disruption times are shorter than 1000 years, and the Lyapunov times are shorter than 100 years.  相似文献   

Specific features of the distribution of trace and rare earth elements in recent bottom sediments in the lower course of the Severnaya Dvina River and White Sea     

A. V. Maslov  V. P. Shevchenko  V. N. Podkovyrov  Yu. L. Ronkin  O. P. Lepikhina  A. N. Novigatsky  A. S. Filippov  N. V. Shevchenko 《Lithology and Mineral Resources》2014,49(6):433-460

The paper discusses results of the lithogeochemical examination of recent bottom sediments in the lower course of the Severnaya Dvina River and White Sea. It has been established that the average concentration of several trace elements (Hf, Sc, Co, Y, Ni, V, Cr, Zr, Ba, and others) therein correlates with the content of the silt-pelite fraction. Maximal concentrations of the majority of above elements are confined to the silty-clayey sediments at the Basin/Dvina Bay boundary. They localized near the coastal zone only for some clastophile (Zr, Cr, and others). Typical values of the hydrolyzate module, chemical index of alteration, and Al₂O₃/SiO₂ ratio in the aleuropelitic and pelitic sediments of the Severnaya Dvina River delta, Dvina Bay, and the Dvina Bay Basin boundary suggest that these sediments are confined to sufficiently cold climate settings. Data points of sediment composition in discriminant paleotectonic diagrams are scattered over a large field probably due to high contents of the weakly weathered plagioclases, micas, and amphiboles, as well as the hydrogenic process promoting the accumulation of Fe and Mn. The PAAS-normalized spectra of rare earth elements (REE) in bottom sediments of the Pinega and Severnaya Dvina rivers, marginal filter of the latter river, Dvina Bay, and the Dvina Bay Basin boundary are similar to the REE distribution in clayey rocks of the ancient platform cover (except for a slight positive Eu anomaly). The REE systematics and distribution pattern of compositional data points of recent bottom sediments in the Gd_N/Yb_N-Eu/Eu* and Eu/Eu*-Cr/Th diagrams and values of several indicator ratios of trace elements suggest that the studied rocks were formed by the mixing of clastic materials from geochemically contrast provenances: northwestern provenance (Kola-Karelia geoblock), which is mostly composed of the Archean and Early Proterozoic crystalline complexes, and the southeastern provenance (northwestern periphery of the Mezen syncline), which is almost totally composed of Phanerozoic sedimentary rocks. The latter provenance likely played a crucial role in the geochemical signature of recent bottom sediments over a significant area of the White Sea.  相似文献   

USE OF SPACE IMAGERY IN COMPILING ENVIRONMENTAL-PROTECTION MAPS (with reference to the Soligorsk potash-mining district)     

V. A. Sushchenya  L. A. Shevchenko  V. I. Somova 《地理信息系统科学与遥感》2013,50(1):15-32

The authors apply remote sensing data to the mapping of natural envionment with a focus on environmental protection. The technique is illustrated with particular reference to a largely swampy potash-mining deposit in Belorussia which is the largest potash producer of the USSR, accounting for 54% of its total output in 1983. Translated from: Kartografirovaniye po kosmicheskim snimkam i okhrana okruzhayushchey sredy (Mapping from Space Imagery and Protection of the Environment), edited by Ye. A. Vostokova et al., Moscow: Nedra, 1983, pp. 177-195.  相似文献   

Statistical characteristics of the Northwestern Pacific abyssal irregularities and their potential impact on the tsunami propagation     

G. V. Shevchenko  V. N. Patrikeev 《Russian Journal of Pacific Geology》2012,6(6):444-447

A set of echograms obtained during the course of the Pacific Transects project in the second half of 1980 was digitized with a similar step within a distance of 1 mile. Based on the processing of these materials, the spectral and statistical characteristics of the irregularities of the bottom topography of the Northwestern Pacific were obtained. It was shown that the decrease of the spectral density within the wavelength range from 2 to 100 miles is well consistent with the k^?2 law with the subdivision of the spectrum into two ranges: the small-scale (2–8 miles long and 50 m high) and medium-scale (10–40 miles long and 120 m high) ones. The dampening decrement of the tsunami wave due to the interaction with the irregularities of the bottom topography accounted for γ = 0.2 hr^?1 for the forward scattering and 0.1 hr^?1 for the back scattering. The forward scattering provides the transformation of the initial single pulse into the wave train, the delay of the maximum wave with respect to the arrival time of the tsunami, and the increase in the duration of the oscillations.  相似文献   

Major and Trace Elements in Water and Suspended Matter of the Northern Dvina River and Their Annual Discharge into the White Sea     

Gordeev  V. V.  Kochenkova  A. I.  Starodymova  D. P.  Shevchenko  V. P.  Belorukov  S. K.  Lokhov  A. S.  Yakovlev  A. E.  Chernov  V. A.  Pokrovsky  O. S. 《Oceanology》2021,61(6):994-1005

Oceanology - The results of continuous four-year-long investigations (from May 2015 to April 2019) of the elemental composition of water and suspended matter in the Northern Dvina River are given....  相似文献   

Oxygen isotope composition of water and snow-ice cover of isolated lakes at various stages of separation from the White Sea     

A. P. Lisitzin  Yu. K. Vasil’chuk  V. P. Shevchenko  N. A. Budantseva  E. D. Krasnova  A. N. Pantyulin  A. S. Filippov  Ju. N. Chizhova 《Doklady Earth Sciences》2013,449(2):406-412

This study aimed to analyze the oxygen isotope composition of water, ice, and snow in water bodies isolated from the White Sea and to identify the structural peculiarities of these pools during the winter period. The studies were performed during early spring in Kandalaksha Bay of the White Sea, in Velikaya Salma Strait and in Rugoserskaya Inlet. The studied water bodies differ in their degree of isolation from the sea. In particular, Ermolinskaya Inlet has normal water exchange with the sea; the Lake on Zelenyi Cape represents the first stage of isolation; i. e., it has permanent water exchange with the sea by the tide. Kislo-Sladkoe Lake receives sea water from time to time. Trekhtsvetnoe Lake is totally isolated from the sea and is a typical meromictic lake. Finally, Nizhnee Ershovskoe Lake exhibits some features of a saline water body. The oxygen isotope profile of the water column in Trekhtsvetnoe Lake allows defining three layers; this lake may be called typically meromictic. The oxygen isotope profile of the water column in Kislo-Sladkoe Lake is even from the surface to the bottom. The variability of δ¹⁸O is minor in Lake on Zelenyi Cape. A surface layer (0–1 m) exists in Nizhnee Ershovskoe Lake, and the oxygen isotope variability is well pronounced. Deeper, where the freshwater dominates, the values of ?18Îvary insignificantly disregarding the water depth and temperature. This fresh water lake is not affected by the seawater and is not stratified according to the isotope profile. It is found that applying the values of ?18Î and profiles of temperature and salinity may appear as an effective method in defining the water sources feeding the water bodies isolated from the sea environment.  相似文献   

Forms of some metals in the suspended sediments of the Northern Dvina River and their seasonal variations     

V. V. Gordeev  V. P. Shevchenko 《Oceanology》2012,52(2):261-270

The results of the analysis of samples of the Northern Dvina River’s suspended particulate matter obtained by the sedimentation method from large water volumes in the periods of the spring high water and summer low water are presented. By the method of sequential leaching using different reagents, four fractions have been separated: the F1 is the sorbed complex and carbonates, the F2 is the amorphous hydroxides of Fe and Mn, the F3 is the form connected with the organic matter, and the F4 is the residual or silicate-detrital (inert) form. The data have shown that all ten elements determined were grouped with respect to the ratio of the distinguished forms: F4 is the predominant form for Al and Fe (73–88% of all the forms; however, the summer sample contains only 38% of this form of iron, and F2 is the predominant form for this period with 46.6%). As to Mn, the F1, F2, and F4 are nearly equally distributed in the spring high water samples, and only the F3 form is less important (5.4%). In the summer sample, the manganese sorbed complex is predominant (53.5%); for Cu, Ni, Cr, and Co, the inert F4 form is predominant (60–70%) in the sample of the spring suspended matter. The summer low water suspended matter has a lower F4 contribution (25–45%); for Zn, Pb, and Cd, the equal distribution of the forms in the spring samples is typical, while the summer suspended matter differs by the F2 form’s predominance (53–61% for Zn and Pb). The main conclusion from the acquired data is that the geochemical mobility of all the studied elements, except for cadmium, in the summer low water suspended matter is higher than in the spring suspended matter. The more intensive biogeochemical processes in August, the high level of organic matter, and the higher contribution of phytoplankton lead to the intensification of the metals’ geochemical activity in the Northern Dvina suspended matter in the end of the summer compared to the spring high water period when the physical processes are predominant over the biogeochemical ones due to the high speeds of the freshened waters flow.  相似文献