Simulation of molecular mass distributions and evaluation of O<Superscript>2−</Superscript> concentrations in polymerized silicate melts     

A. A. Ariskin  V. B. Polyakov 《Geochemistry International》2008,46(5):429-447

A new statistical model is proposed for the molecular mass distributions (MMD) of polymerized anions in silicate melts. The model is based on the known distribution of Q ⁿ species in the MeO-Me₂O-SiO₂ system. In this model, chain and ring complexes are regarded as a random series of Q ⁿ structons with various concentrations of bridging bonds (1 ≤ n ≤ 4, Q ⁰ corresponds to SiO ₄ ^4? ). This approach makes it possible to estimate the probability of formation of various ensembles of polymer species corresponding to the general formula (Si _i O_3i+1?j )^2(i+1?j)?, where i is the size of the ion, and j is the cyclization number of intrachain bonds. The statistical model is utilized in the STRUCTON computer model, which makes use of the Monte Carlo method and is intended for the calculation of the composition and proportions of polyanions at a specified degree of polymerization of silicate melts (STRUCTON, version 1.2; 2007). Using this program, we simulated 1200 MMD for polyanions in the range of 0.52 ≤ p ≤98, where p is the fraction of nonbridging bonds in the silicon-oxygen matrix. The average number of types of anions in this range was determined to increase from three (SiO ₄ ^4? , Si₂O ₇ ^6? , and Si₃O ₁₀ ^8? ) to 153, and their average size increases from 1 to 7.2. A special option of the STRUCTON program combines MMD reconstructions in silicate melts with the formalism of the Toop-Samis model, which enables the calculation of the mole fraction of the O^2? ion relative to all anions in melts of specified composition. It is demonstrated that, with regard for the distribution and average size of anion complexes, the concentration of the O^2? ion in the MeO-SiO₂ system is characterized by two extrema: a minimum at 40–45 mol % SiO₂, which corresponds to the initial stages of the gelenization of the polycondensated silicate matrix, and a maximum, which is predicted for the range of 60–80 mol % SiO₂.  相似文献   

Mercury in the bottom sediments of the marginal filter of the Razdol’naya River,Amur Bay     

D. M. Polyakov  K. I. Aksentov  M. V. Ivanov 《Geochemistry International》2008,46(6):614-621

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Speciation,Size Fractionation and Transport of Trace Elements in the Continuum Soil Water–Mire–Humic Lake–River–Large Oligotrophic Lake of a Subarctic Watershed     

Svetlana M. Ilina  Sergey A. Lapitskiy  Yuriy V. Alekhin  Jérôme Viers  Marc Benedetti  Oleg S. Pokrovsky 《Aquatic Geochemistry》2016,22(1):65-95

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HCl content has ceased to increase in the atmosphere of the Northern Hemisphere     

Yu. M. Timofeev  A. V. Polyakov  A. V. Poberovsky 《Doklady Earth Sciences》2016,470(1):994-996

According to the spectroscopy data on the HCl content analyzed in Peterhof in 2009–2016 and in a number of NDACC stations in the Northern Hemisphere, growth in the HCl content observed since 2007 and caused by changes in the stratospheric circulation stopped in 2010–2011. As follows from the experimental data, a decrease in the HCl content estimated in Peterhof at 4.4 × 10¹³ cm^–2/year or ~1.0%/year started again.  相似文献   

Tululite,Ca14(Fe3+,Al)(Al,Zn,Fe3+,Si,P,Mn,Mg)15O36: a new Ca zincate-aluminate from combustion metamorphic marbles,central Jordan     

Hani N. Khoury  Ella V. Sokol  Svetlana N. Kokh  Yurii V. Seryotkin  Elena N. Nigmatulina  Sergei V. Goryainov  Elena V. Belogub  Ian D. Clark 《Mineralogy and Petrology》2016,110(1):125-140

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Investigation of Water-Exchange Processes in the Caspian Sea on the Basis of Isotopic and Oceanographic Data     

Ferronsky  V. I.  Brezgunov  V. S.  Vlasova  L. S.  Polyakov  V. A.  Froehlich  K.  Rozansky  K. 《Water Resources》2003,30(1):10-22

Results of the sampling for temperature, salinity, and isotopic composition of water masses that was performed in the Caspian Sea at deepwater stations along a meridional profile during the international expeditions of 1994–1996 are presented. The water-exchange processes in this basin are analyzed on the basis of the distributions of salinity and isotopes in space and time.  相似文献   

Some information on testate amoebae of Iceland     

Vera Opravilová  Svetlana Zahrádková 《Limnologica》2003,33(2):131-137

In samples of mosses collected during an expedition in the year 1987 along the southern border of Iceland, in seven habitats on the slopes of Skerhöll Hill, south of the glacier Svínafellsjökull, 80 taxa of testate amoebae have been recorded. From these taxa 24 species are new to Iceland. Up to now, including our own data, on the basis of available sources 174 taxa have been reported for Iceland. In the mosses Racomitrium heterostichum and Racomitrium fasciculare an Assulina muscorum — Centropyxis globulosa-association has been recorded.  相似文献   

Principal goals and preliminary results of the studies from R/V Rift in the Caspian Sea (April–May, 2006)     

L. I. Lobkovsky  L. R. Merklin  S. A. Kovachev  A. K. Ambrosimov  V. E. Verzhbitsky  A. S. Polyakov  A. G. Roslyakov  O. V. Levchenko  A. D. Mutovkin  A. S. Zverev  A. A. Meluzov  B. N. Grin’ko  N. V. Libina  V. A. Poutans  V. Yu. Slobodyan 《Oceanology》2007,47(5):741-745

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Natural Molecular Hydrogen Seepage Associated with Surficial,Rounded Depressions on the European Craton in Russia     

Nikolay Larin  Viacheslav Zgonnik  Svetlana Rodina  Eric Deville  Alain Prinzhofer  Vladimir N. Larin 《Natural Resources Research》2015,24(3):369-383

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