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1.
A series of hydrodynamical models of type-II supernova outbursts (SNII) has been calculated. Approximate relations connecting the total outburst energy ε, the mass of envelope ejectedM, the presupernova radiusR, and the amount of ionizing quanta radiated by the supernovaeN H with such values as the duration of the light curve plateau Δt, and absolute magnitude in the wavelength bandV and photospheric velocityU PH observed near the middle of the plateau have been established. Advantage has been taken of the relations to obtain a preliminary evaluation for the characteristics of the average SN II: ε=7×1050 erg,M=6M ⊙,R=500R ⊙,N H=2×1058. The SNIIs with plateau-like light curves seem to be accounted for by thermonuclear explosions of degenerate cores of red giant stars and result in a total disruption of the star without any stellar remnant. To the contrary, SNIIs with linear light curves have substantially different properties (in particular, they throw considerably less massive envelopes off). These SNII must signify the birth of collapsed objects—neutron stars (pulsars) or black holes. 相似文献
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T. V. Litvinova 《Lithology and Mineral Resources》2014,49(5):416-426
The electron microscopic study of stromatolites in the northern Anabar region revealed that the cyanobacterial colony represents a community of diverse microorganisms making up a very thin biofilm on the mineral layer surface. The morphology of fossilized bioparticles and their mutual arrangement in organogenic layers alternating with mineral layers play a crucial role in the formation of specific (banded, varved, clotted, and others) rock microstructures, which served as a basis for the classification of stromatolites. 相似文献
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T. M. Timakova T. P. Kulikova I. A. Litvinova T. N. Polyakova M. T. Syarki E. V. Tekanova T. A. Chekryzheva 《Water Resources》2014,41(1):78-86
Long-term changes in the quantitative and structural characteristics of bacterio-, phyto-, zooplankton, and macrozoobenthos are studied in a water body subject to pollution by effluents of pulp and paper production. The key effect on the state of biocenoses is shown to be due to anthropogenic load and the qualitative changes in the composition of industrial wastes after nature protection measures taken at the plant. Differences are revealed in the character, stages, and direction of transformations in planktonic and benthic communities. The most significant changes in biota have taken place after the commissioning of biological treatment facilities and diffusing wastewater discharge, resulting in accelerated eutrophication of the basin and redistribution of transformed biocenoses over areas within the water body. A decrease in the load during production decline demonstrated the possible deeutrophication of the ecosystem. 相似文献
4.
N. M. Kalinkina T. P. Kulikova I. A. Litvinova T. N. Polyakova M. T. Syarki E. V. Tekanova T. M. Timakova T. A. Chekryzheva 《Water Resources》2012,39(7):776-783
The situation in the Kondopozhskaya Bay of Onega Lake, polluted by wastewater of a pulp-and-paper mill is considered. The dynamics of wastewater input over 80 years is analyzed; the rate of such input varied widely in this period because of changes in cellulose production processes. A close correlation was found to exist between the characteristics of the state of aquatic organism communities and the environmental physicochemical characteristics. The pollution indices of water mass and the bed are evaluated, including biological and physicochemical data. Those indices can be used to identify polluted zones of water and bottom sediments in Onega Lake subject to the discharge of wastewaters from pulp-and-paper mill. 相似文献
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Precambrian stromatolites were studied with a complex approach including two complementary methods. The biogenic origin of ultramicrostructures examined with SEM was supported by the traditional optical microscopy. The paper addresses columnar-stratiform stromatolites of the Vendian Chencha Formation in the Ura Uplift (Baikal–Patom Highland, Central Siberia) and fossilized remains of coccoidal and filamentous microorganisms therein: cyanobacteria Eoentophysalis, hormogonian cyanobacteria Siphonophycus and, probably, Eomicrocoleus. The unraveled community of stromatolite builders includes the major organisms commonly observed in the Precambrian microbiota. Stromatolites of the Chencha Formation contained not only cyanobacteria, but also remains of eukaryotic microorganisms, including likely testate amoebae and acanthomorphic acritarchs. It is shown that the complex approach rules out incorrect determination of biota and significantly enhances concepts of the origin and formation of stromatolites, as well as the participation of microorganisms in their formation. 相似文献
7.
T. V. Litvinova 《Lithology and Mineral Resources》2009,44(4):389-398
Lamination, a characteristic feature of stromatolites, is related to thin alternation of mineral and organogenic layers. The present paper is devoted to structures of Lower Riphean stromatolites in the Fomich River area (northern Anabar Uplift) that were described for the first time and studied with an electron microscope. Two Colonnella forms with different microstructures were examined. It has been established that a banded texture is observed if an organogenic layer is mainly composed of tightclusters of filiform (theread like) particles. However, a clotted texture is recorded if the layer is represented by isolated coccomorphic (rounded) particles. The chemical composition of these tiny structures, which can accumulate several elements, is discussed and analyzed. In the past, the organogenic layer represented a biofilm that comprised a complex-function cyanobacterial community. 相似文献
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A. V. Litvinenko N. N. Filatov M. S. Bogdanova V. A. Karpechko I. A. Litvinova Yu. A. Salo 《Water Resources》2014,41(4):454-463
Stages of anthropogenic transformation of Vygozero are demonstrated. Hydrographic and hydrologic characteristics are given to the Vogozersko-Ondskoe Reservoir and its drainage area at different stages of its development. The current state and dynamics of the economic use of the reservoir and its watershed are estimated with the use of GIS-technologies (databases and GIS “Water Users of the Republic of Karelia”). 相似文献
9.
A. I. Khanchuk I. Yu. Rasskazov V. G. Kryukov N. M. Litvinova B. G. Saksin 《Doklady Earth Sciences》2016,470(2):1031-1033
Platinum is revealed by the authors in the Mn ores from the South Khingan deposit of Malyi Khingan. Its quality (grain size, aggregates) and amount are of economic interest. Platinum has higher contents of Fe, Cu, Mn, Ni, Os, and other metals. The Pt potential is related to carbonaceous metasomatites, which replaced fluidolites. 相似文献
10.
T. V. Litvinova 《Lithology and Mineral Resources》2007,42(4):384-399
The global Vendian-Cambrian epoch of phosphate accumulation is marked by the virtually synchronous appearance of giant sedimentary basins, where the largest phosphate-bearing provinces were formed in a relatively short time span. The paper is devoted to one of the main problems in phosphate geology, namely the origin of phosphate pellets. They are observed as microscopic particles in the stratified microgranular phosphorites formed during the Vendian-Cambrian epoch. Different forms of pellets from the productive formation of the Lesser Karatau were studied with the scanning electron microscope. The morphogenetic comparison of phosphate particles and microbiota found in the Vendian-Cambrian or older rocks was carried out. The distribution of major chemical elements in different pellets was studied for the first time. Based on the results obtained, regularities of the vertical and lateral distribution of phosphate pellets in the Lesser Karatau and the issue of their origin is discussed. 相似文献