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1.
A. V. Ivanova V. L. Afanasiev P. P. Korsun A. R. Baranskii M. V. Andreev V. A. Ponomarenko 《Solar System Research》2012,46(4):313-319
The results of the photometric observations of comet 29P/Schwassmann-Wachmann 1 are analyzed. The comet demonstrates substantial activity at heliocentric distances larger than 5 AU, i.e., outside the water ice sublimation zone. The CCD images of the comet were obtained in wideband R filters at the 6-meter telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) and at the 2-meter Zeiss-2000 telescope of the Peak Terskol Observatory. The processing of the images with special digital filters allowed the active structures (jets) to be distinguished in the dust coma of the comet. With the cross-correlation method, the rotation period of the cometary nucleus was determined as 12.1 ± 1.2 and 11.7 ± 1.5 days for the observations taken in December 2008, and February 2009, respectively. The probable causes of the difference in the estimates of the rotation period of the cometary nucleus obtained by different authors are discussed. 相似文献
2.
V. R. Lozovsky M. G. Minikh T. A. Grunt D. A. Kukhtinov A. G. Ponomarenko I. D. Sukacheva 《Stratigraphy and Geological Correlation》2009,17(6):602-614
The resolution of the Commission on the Permian System of the Interdepartmental Stratigraphic Committee (ISC) to exclude the
Ufimian Stage from the General (East European) stratigraphic scale is questioned. This resolution led to substantial changes
in the charactristics of several stage units and violated rules of the stratigraphic nomenclature. The paleontological characteristic
of the Ufimian Stage differs from that of the Kungurian Stage in its initial volume. It is shown that the Ufimian Stage is
characterized by its high correlation potential. 相似文献
3.
In the Noril’sk ore field, parkerite is a characteristic mineral of sulfide ore that metamorphosed under conditions of zeolite and prehnite-pumpellyite facies and of arsenide-calcite veins. The mineral occurs in ores containing bornite, anhydrite, magnetite, mackinawite (3–5 wt % Ni), valleriite, calcite, ankerite, native silver, native bismuth, violarite, Te-rich bismutohauchecornite, cupropentlandite enriched in Fe, Pd-rich breithauptite (1.5–2.5 wt % Pd), galena enriched in Cu (3.8 wt % Cu), and Ni arsenides and antimonides. Parkerite occurs in those place, where the primary ores have contained pockets and veins of graphic galena and chalcopyrite aggregates with associated Pt-Pd-Au-Ag minerals. Parkerite metacrysts in galena and Fe-Cu-Ni sulfides contain 6–16 and up to 5 wt % Pb, respectively. Parkerite rims replacing PGM aggregates and galena contain 1–3 wt % Pb. In calcite veins hosted in metamorphosed sulfide ores, parkerite is associated with native silver and bismuth, maucherite, cobaltite, chalcocite, and uraninite. Parkerite from these veins contains up to 0.5 wt % Pb. Thus, the Pb and Bi contents in parkerite basically depend on those of replaced minerals. Rare bismutohauchecornite is associated with parkerite. 相似文献
4.
A.F. Belenov L.M. Erukhimov P.V. Ponomarenko Y.M. Yampolski 《Journal of Atmospheric and Solar》1997,59(18):2367-2372
Quasiperiodical variations in the Doppler shift of HF signals scattered by artificial ionospheric turbulence have been investigated experimentally. It is assumed that a possible cause for these variations might be natural ionospheric MHD-waves. The amplitude of the magnetic component of such waves resulting in the observed Doppler shift magnitudes has been estimated as 1 γ. 相似文献
5.
Aleksander Jokic Elena Ponomarenko Darwin W Anderson 《Geochimica et cosmochimica acta》2003,67(14):2585-2597
X-ray absorption near-edge structure (XANES) and nuclear magnetic resonance (NMR) spectroscopy were used in combination to characterize organic carbon structures in a series of wetland soils in Saskatchewan, and XANES spectroscopy was also used to examine sulphur speciation in the soils. The organic C contents of most of the wetland soils are consistently higher by a factor of two to five times compared to adjacent well-drained soils. NMR analyses indicate that the organic matter in the wetland soils consists of predominantly aliphatic structures such as carbohydrates and long chain poly(methylene) units which are refractory structures found in plant waxes. The poly(methylene) structures have a significant capacity to sorb nonpolar organic molecules. The phenolic OH and carboxyl group content of the wetland soils studied is an additional significant factor in their sequestering ability for heavy metals or pesticides. Carbon XANES spectroscopy shows that the surface (∼10 nm) layer of particulate organic matter has a structure dominated by aromatic, carbohydrate and carboxylic acid-like material apparently derived from partially degraded lignin and cellulose polymers which are adsorbed onto clay minerals. The aliphatic structures remaining in this surface layer are probably recalcitrant (poly)methylene units. At a depth of ∼100 nm, the aliphatic content significantly increases suggesting the presence of more labile structures. The presence of these more labile aliphatic compounds may be due to slow decomposition rates in the wet, often cool environments present and to the protective action of the more refractory components in the surface ∼10 nm of the organic matter. Drying of the wetlands, either by draining or as a result of climate change, is likely to result in the rapid decomposition of these labile organic structures releasing carbon dioxide. Our data indicate that the preservation of the organic carbon compounds in these soils is a result of their presence as surface adsorbed layers on the soil mineral particles. The soils contain three different classes of sulphur compounds: reduced organic sulphur such as sulphides, low valent oxidized sulphur such as sulphoxides, and high valent oxidized sulphur such as sulphonate and sulphate. Of these, reduced sulphur species constitute between one-third and two-thirds of the total. Sulphonate structures comprise between a fifth and a third of the total. Sulphates exhibit a wide variation in content, and sulphoxides are either not detected or are present to a lesser extent (<5%). Drying of the wetlands would cause oxidation of sulphides to sulphates. 相似文献
6.
Dell Sergius Abakumov Ivan Znak Pavel Gajewski Dirk Kashtan Boris Ponomarenko Andrey 《Studia Geophysica et Geodaetica》2019,63(4):538-553
Studia Geophysica et Geodaetica - Imaging of small-scale heterogeneities is important for the geological exploration in complex environments. It requires a processing sequence tuned to... 相似文献
7.
Krek A. V. Paka V. T. Krek E. V. Ezhova E. E. Dorokhov D. V. Kondrashov A. A. Bubnova E. S. Ponomarenko E. P. Bashirova L. D. Kapustina M. V. 《Oceanology》2019,59(5):803-805
Oceanology - The 44th cruise of R/V Akademik Boris Petrov was carried out from October 5 to 30, 2018 in the Baltic Sea and Skagerrak Strait. The studies included investigation of the water column... 相似文献
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9.
The article is dedicated to the lithological-paleoecological analysis of Upper Devonian fenestral limestones from different areas of the Timan-northern Ural region, which reflect paleogeographic settings from the coastal zone to the marginal part of the shelf. It is established that their main structural elements are represented by fenestrae, peloids, calcispheres, and occasional microzoo- and phytobenthos remains. The presence of a dark micritic envelope on calcispheres is their specific textural feature. The envelope of calcispheres represents mineralized vegetable mucus, which reflects their planktonic type of dwelling. These structures include representatives of radiolarian skeletons, Charophyceae and Chlorophyceae algae, and foraminiferal tests. The trophic system consists of five levels. Carbonate sediments accumulated in relatively shallowwater and lagoonal settings occupied mostly by tidal and shallow-water subtidal microbial mats. In these lagoons, intermittently limited circulation stimulated the formation of anoxic conditions in bottom waters. Development of anoxic conditions in the bottom water layer, sulfate reduction, and freshwater influence determined the formation of a specific paleocoenosis of fenestral limestones, which could not form biogenic frameworks. 相似文献
10.
V. R. Lozovsky Yu. P. Balabanov E. V. Karasev I. V. Novikov A. G. Ponomarenko O. P. Yaroshenko 《Stratigraphy and Geological Correlation》2016,24(4):364-380
The comprehensive analysis of the data obtained on terrestrial vertebrata, ostracods, entomologic fauna, megaflora, and microflora in deposits of the Vyaznikovian Horizon and Nedubrovo Member, as well as the paleomagnetic data measured in enclosing rocks, confirms heterogeneity of these deposits. Accordingly, it is necessary to distinguish these two stratons in the terminal Permian of the East European Platform. The combined sequence of Triassic–Permian boundary deposits in the Moscow Syneclise, which is considered to be the most complete sequence in the East European Platform, is as follows (from bottom upward): Vyatkian deposits; Vyaznikovian Horizon, including Sokovka and Zhukovo members; Nedubrovo Member (Upper Permian); Astashikha and Ryabi members of the Vokhmian Horizon (Lower Triassic). None of the sequences of Permian–Triassic boundary deposits known in the area of study characterizes this sequence in full volume. In the north, the Triassic deposits are underlain by the Nedubrovo Member; in the south (the Klyazma River basin), the sections are underlain by the Vyaznikovian Horizon. The Permian–Triassic boundary adopted in the General Stratigraphic Scale of Russia for continental deposits of the East European platform (the lower boundary of the Astashikha Member) is more ancient than the one adopted in the International Stratigraphic Chart. The same geological situation is observed in the German Basin and other localities where Triassic continental deposits are developed. The ways of solving this problem are discussed in this article. 相似文献