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Knüsel S Piguet DE Schwikowski M Gäggeler HW 《Environmental science & technology》2003,37(10):2267-2273
Trace elements trapped in glaciers are important indicators for the characterization of past biogeochemical cycles, the identification of numerous sources and their varying strength, and thus indirectly provide insight into past climate variations. However, this necessitates highly resolved and continuous records of trace elements in ice. To obtain records corresponding to these requirements, a continuous ice-core melting (CIM) device was coupled to an inductively coupled plasma sector field mass spectrometer (ICP-SFMS). Accuracy of this newly developed method was tested by replicate analysis of longitudinally cut ice-core sections (reproducibility) and by comparing results of the continuous method with the conventional decontamination and analysis procedure. The new, fast method is suited to accurately determine concentrations of a number of elements, such as Li, Na, Mg, Ca, Mn, Co, Br, Sr, Mo, and Tl. However, for 18 elements (including Al and lanthanides) observed concentrations were underestimated when analyzed using the continuous method. Possible explanations of these low concentrations are (i) incomplete dissolution of mineral dust particles contained in the ice resulting from a delayed acidification step and/or (ii) adsorption of dissolved trace elements or mineral dust particles on the surface of the ice melting device. 相似文献
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The selectivity of metal oxide gas sensors (MOG) can be improved significantly by forming composites with solid ionic conductor additives. First investigations were done using model composites of SnO2/Natrium Super Ionic Conductor (NASICON) with the result of a huge sensitivity enhancement to substances ending with R–OH, R–HO or R–COOH groups and a reduction of sensitivity to other gas components. This selectivity of the new composite to those functional groups could be confirmed by catalytic conversion measurements with FTIR-spectroscopy at three gas components, respectively. The specific conductivity of the NASICON containing composites is significantly lower than that of pure SnO2. Advanced studies show that the activation energy of the bulk-conductivity increases by approximately 30% in the presence of NASICON. In spite of high volume parts of NASICON (20%), no polarization effects were found (a complete Ohmic current–voltage behavior) and mainly the resistive part of the electrical impedance is influenced. 相似文献
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Karl Heinz Kienitz 《控制论与系统》2013,44(6):647-654
Modifications to Zadeh's theory of approximate reasoning are proposed to enhance the theory's ability to produce plausible inference results. The modifications include the introduction of a different implication definition and a certainty qualification for fuzzy propositions. Plausible reasoning is characterized by a set of reasoning patterns of practical significance. This set is then used to validate the overall approximate reasoning method. 相似文献
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S. V. Alekseenko A. V. Cherdantsev O. M. Heinz S. M. Kharlamov D. M. Markovich 《Pattern Recognition and Image Analysis》2011,21(3):441-445
The secondary instability of the surface of a liquid film sheared by an intensive gas flow was first discovered using high-speed
modification of the laser-induced fluorescence method. To study the space-temporal evolution of waves of different types,
we used image analysis tools, in particular, the Canny method. As a result, we obtained the quantitative characteristics for
both wave types and the phenomenon of the back slope instability of primary waves. 相似文献
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Daniel Lersch Gheorghe Pascovici Benedikt Birkenbach Bart Bruyneel Jürgen Eberth Herbert Hess Peter Reiter Andreas Wiens Heinz Georg Thomas for the AGATA Collaboration 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,640(1):223
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