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Now showing items 6936-6955 of 39124
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(2004)The hydroxy groups of the crystal lattice of dioctahedral 2:1 phyllosilicates were investigated by means of quantum-mechanical calculation. The standard Kohn-Sham self-consistent density functional theory (DFT) method was ...
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(2003)Ikaite is a metastable hexahydrate of calcium carbonate, forming in aqueous conditions near freezing conditions. Neutron powder diffraction data of synthetic deuterated ikaite, collected at seven temperatures from 4 to 270 ...
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(2003)Hydrogen diffusion coefficients in natural orthopyroxenes and synthetic enstatite were determined by dehydration and hydration experiments at 700 and 900 °C. In natural Opx (approximately En90Fs10) small but significant ...
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(2000)Several of the supposedly anhydrous major minerals of the upper mantle have been shown to regularly contain small amounts of hydrogen. The concentrations measured in the most important minerals obtained from mantle xenoliths ...
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HYDROGEN IN SOME NATURAL GARNETS STUDIED BY NUCLEAR REACTION ANALYSIS AND VIBRATIONAL SPECTROSCOPY (2003)A suite of 11 gem-quality, optically completely clear garnet crystals with a broad variety of compositions in the space of the end members pyrope-almandine-spessartine-grossular-andradite-goldmanite were analyzed for trace ...
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(2001)The mechanisms of exchange of hydrogen between the deep interior and surface of Earth, as well as the means of retention and possible abundance of hydro-gen deep within the Earth, are examined. The uppermost several hundred ...
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(2001)Bulk and step-heating hydrogen isotope measurements of glassy and vesicular samples from three young rhyolite lavas demonstrate for the first time that magmatic H2O can be distinguished from meteoric H2O added during ...
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(2004)We present new hydrogen isotope data for separated matrix, hydrated chondrules, and other hydrated coarse silicate fragments from nine carbonaceous chondrites. These data were generated using a micro-analytical method ...
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(1998)We have investigated the changes in the ratio of stable isotopes of hydrogen when cellulose is subjected to thermal stress at the high temperatures of 180°C and 200°C, respectively. The thermal stress caused deuterium ...
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(2003)Hydrogen isotope exchange between water and orthosilicic acid (H4SiO4) was modeled using B3LYP calculations and classical transition-state theory. Configurations of 1, 2, 3 and 7 water molecules and H4SiO4 were used to ...
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(1997)Hydrogen isotope exchange between tourmaline and water has been studied experimentally over the temperature range of 800-350°C. The hydrogen isotope equilibrium fractionation factor between tourmaline and water may be ...
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(1989)A series of experiments was performed to determine the hydrogen isotope fractionation factors between water vapor and “water” dissolved as hydroxyl groups in rhyolitic and feldspathic glasses and melts. Experiments were ...
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(1996)The equilibrium hydrogen isotope fractionation factor (α) between kaolinite and water in the temperature range 330 to 0°C is 1000 ln αkaol-water = ?2.2 ? 106 T?2 ? 7.7. This monotonic expression is based on a combination ...
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HYDROGEN ISOTOPE FRACTIONATION IN LIPIDS OF THE METHANE-OXIDIZING BACTERIUM METHYLOCOCCUS CAPSULATUS (2002)Hydrogen isotopic compositions of individual lipids from Methylococcus capsulatus, an aerobic, methane-oxidizing bacterium, were analyzed by hydrogen isotope-ratio-monitoring gas chromatography–mass spectrometry (GC-MS). ...
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(2001)We determined the stable hydrogen isotope fractionation during progressive vaporization of three n-alkanes (heptane or C7, octane or C8, nonane or C9) at 24+/-1<space>°C, in an effort to understand the environmental isotopic ...
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(2003)The temperature and hydrogen isotope composition of the fumarolic gases have been studied at Kudriavy volcano, Kurile Islands, which is unique for investigating the processes of magma degassing because of the occurrence ...
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(2004)The source of water responsible for serpentinite formation is one of the oldest problems in geology. Some data on the isotopic composition of such metamorphic water can be obtained from the isotopic composition of the ...
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(2003)Distribution of hydrogen and carbon isotopes (D/H and 13C/12C) in the microbial systems CH4–H2O and CH4–CO2 was studied in differentworld’s regions. According to the distribution of these isotopes in the above systems, two ...
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HYDROGEN ISOTOPE RATIOS OF RECENT LACUSTRINE SEDIMENTARY N-ALKANES RECORD MODERN CLIMATE VARIABILITY (2004)Hydrogen isotope ratios were measured on n-alkanes (n-C12 to n-C31) extracted from recent lake surface sediments along a N-S European transect to test if modern climate variability is recorded in these biomarkers. δD values ...
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(1996)Hydrogen isotope fractionation factors were measured for coexisting brines and vapors formed by phase separation of NaCl/H2O fluids at temperatures ranging from 399-450oC and pressures from 277-397 bars. It was found that ...
Now showing items 6936-6955 of 39124