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Abstract Applications of isotopically distinct sulfur compounds have recently been used for tracing the fate of added sulfur in whole catchments or sub-compartments therein. Basic principles, the analytical methodology, and data evaluation for this isotope tracer technique are briefly described. We recommend that δ(34)S-values of applied and natural sulfur compounds in the investigated ecosystem should differ by more than 20‰ in order to successfully ascertain sulfur fluxes. Where possible, a high ratio of applied sulfur loads versus sulfur pool sizes in the ecosystem should also be realized in order to allow the assessment of sulfur transformations in the study area. Prospects and limitations of this isotope tracer technique are critically discussed by reviewing results from recently or currently conducted lysimeter and field experiments. 相似文献
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White DB Tippens WB Abegg R Baldisseri A Boudard A Briscoe W Fabbro B Garçon M Hermes EA Jacobs WW Kessler RS Lytkin L Mayer B Nefkens BM Niebuhr C Petrov AM Poitou J Saudinos J Tomasi-Gustafsson E van der Schaaf A van Oers WT Vigdor SE Wang M 《Physical review D: Particles and fields》1996,53(11):6658-6661
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[formula: see text] Rates of reactions in water can be modified by the presence of antihydrophobic cosolvents such as ethanol and DMSO, which lower the energies of nonpolar surfaces. The rate effects reflect changes both in the solvation of nonpolar surfaces and also in the solvation of polar groups. The effects have been sorted out for some displacement reactions, revealing the geometry of an interesting branching reaction whose two paths show different antihydrophobic effects. 相似文献
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Selzer Y Cabassi MA Mayer TS Allara DL 《Journal of the American Chemical Society》2004,126(13):4052-4053
We report temperature dependence measurements on the conductance of individual molecular wires. The results show for the first time in a molecular junction the theoretically predicted transition from coherent superexchange tunneling conductance to an activated hopping mechanism as temperature is increased. 相似文献
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Dieter H. Mayer 《Journal of statistical physics》1985,38(3-4):785-803
We derive universal scaling properties for k–1 actions on the circle whose generators have rotation numbers algebraic of degreek. As fork=2 these properties can be explained for arbitraryk in terms of a renormalization group transformation. It has at least one trivial fixed point corresponding to an action whose generators are pure rotations. The spectrum of the linearized transformation in this fixed point is analyzed completely. The fixed point is hyperbolic with a (k–1)-dimensional unstable manifold. In the casek=2 the known results are therefore recovered. 相似文献
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Dr. H. Mayer 《Monatshefte für Chemie / Chemical Monthly》1974,105(1):46-54
The crystal structure of Si5O[PO4]6 has been determined and refined by least-squares, using three-dimensional X-raydata fromWeissenberg photographs: space group R 3;a=7.869 andc=24.138 Å;Z=3; 418 independent reflections;R=6.0%. The crystal structure consists of isolated [SiO6] octahedra and [Si2O7] groups which are linked by [PO4] tetrahedra forming a three-dimensional network. The average interatomic distances are: Si[6]?O=1.768, Si[4]?O=1.607 and P?O=1.52i Å. The compound is isotypic with Ge5O[PO4]6. 相似文献