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This paper presents a basic endochronic plasticity model with isotropic hardening for small strain theory according to Valanis. The key point of this model is a convolution integral over an intrinsic time scale involving past values of the strain measure and a so-called memory kernel which leads to a smooth evolution equation for the internal variable. For the temporal discretization of the underlying constitutive equations and the resulting evolution equation we use higher order accurate variational integrators (VI). The remarkable feature is the fact that we approximate the position vector in terms of velocities according to partitioned Runge-Kutta methods (pRK). As a representative model problem serves a quasistatic, uniaxial tensile testing as well as a dynamic, elastoplastic cantilever beam with a smooth plasticity model according to the Valanis framework. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Elisabet Öberg Sascha Ott 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):164-167
Abstract Bis(trimethylsilyl)-terminated C,C-diacetylenic phosphaalkene was prepared from Mes*PCl2 and a propargylic Grignard reagent that in turn was formed from 3-bromo-1,5-bis(trimethylsilyl)penta-1,4-diyne and Rieke-Mg. 相似文献
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Sebastian Wagner Muriel Rakotomalala Frederick Chesneau Thomas Zevaco Manfred Döring 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):781-798
Abstract Organophosphorus compounds such as 6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO, 1) and its derivatives are important and versatile compounds for a broad field of applications. However, a thorough spectral assignment is often subordinate to its chemical properties. This article presents and unambiguously attributes the 1H and 13C NMR spectra of DOPO (1), selected products yielded from the Atherton–Todd reaction (2–4), DOPO-HQ (5) as well as sulfur derivatives (6–7) via a set of 1D- and 2D-NMR experiments. The complex P-C and P-H coupling patterns are discussed and compared with the derivatives possessing different chemical environments around the phosphorus atom. In addition, we compared our results with density functional theory calculations. Even though the prediction of NMR data of organophosphorus compounds via molecular modeling is limited, this study presents a method that yields good results for this class of heterocycles. This knowledge should help to quickly assign NMR spectroscopic data of other DOPO (1) derivatives and can be extrapolated to organophosphorus compounds in general. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: NMR Spectra of Compounds 1-7 (Figures S1 - S15). 相似文献
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Sebastian Schlecht Walter Frank Manfred Braun 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1585-1594
Abstract Tridentate imine ligands that are obtained from the chiral, regioisomeric amino alcohols 2-amino-1,1,2-triphenyethanol and 2-amino-1,2,2-triphenylethanol serve for the formation of bis-chelated silicon complexes. Whereas the complex based on the former amino alcohol is obtained as a diastereomeric mixture, the complex that is derived from 2-amino-1,2,2-triphenylethanol forms in a completely diastereoselective manner, and its configuration is determined as (A,R,R), according to a crystal structure analysis. The new silicon complexes are found to be efficient dopants for the conversion of nematic liquid crystals into cholesteric phases. GRAPHICAL ABSTRACT 相似文献
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Dr. Debangshu Chaudhuri Dr. Eva Sigmund Annemarie Meyer Lisa Röck Philippe Klemm Sebastian Lautenschlager Agnes Schmid Shane R. Yost Prof. Dr. Troy Van Voorhis Dr. Sebastian Bange Prof. Dr. Sigurd Höger Prof. Dr. John M. Lupton 《Angewandte Chemie (International ed. in English)》2013,52(50):13449-13452
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Christine M. J. Gallampois Emma L. Schymanski Mahmoud Bataineh Sebastian Buchinger Martin Krauss Georg Reifferscheid Werner Brack 《Analytical and bioanalytical chemistry》2013,405(28):9101-9112
Many environmental mutagens, including polyaromatic compounds are present in surface waters, often in complex mixtures and at low concentrations. The present study provides and applies a novel, integrated approach to isolate polyaromatic mutagens in river water using a sample from the River Elbe. The sample was taken downstream of industrial discharges using blue rayon (BR) as a passive sampler that selectively adsorbs polyaromatic compounds and was subjected to effect-directed fractionation in order to characterise the compounds causing the detected effect(s). The procedure relies on three complementary fractionation steps, the Ames fluctuation assay with strains TA98, YG1024 and YG1041 with and without S9 activation and analytical screening. Several mutagenic fractions were isolated by combining mutagenicity testing with fractionation. The enhanced mutagenicity in the nitroreductase and/or O-acetyltransferase overexpressing strains YG1024 and YG1041 strains suggested amino- and/or nitro-compounds causing mutagenicity in several fractions. Analytical screening of mutagenic fractions with LC-HRMS/MS provided a list of molecular formulas typically containing one to ten nitrogen and at least two oxygen atoms supporting the presence of amino and nitro-compounds in the mutagenic fractions. Figure
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