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141.
Nathan T. Scharf Annegret Stark Markus M. Hoffmann 《Journal of solution chemistry》2013,42(10):2034-2056
A calorimetric study of dissolution of the ionic liquids (ILs) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C2mim][NTf2]), 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C6mim][NTf2]), and 1-hexyl-3-methylimidazolium tris(trifluoromethylsulfonyl)methide ([C6mim][CTf3]) into chloroform (CHCl3) is presented with particular focus on [C2mim][NTf2]. The interpretation of the calorimetric data for [C2mim][NTf2] was aided by additional NMR self-diffusion measurements and viscosity measurements that through the Stokes–Einstein equation provided information about the average size of the species present. It is evident that the main equilibrium species are ion pairs and aggregates. An estimate for the enthalpy contribution from aggregate formation for [C2mim][NTf2] was found to be ?2.09 kJ per mol of added IL at 288.2 K and slightly decreasing in magnitude to ?1.11 kJ·mol?1 at 318.2 K. While all three ILs release heat upon dissolution into CHCl3, different temperature trends are observed demonstrating the fine balance of competing contributions from breaking IL interactions, cavity formation for the solutes to reside in, and the establishment of new solute–solvent interactions. 相似文献
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We discuss a stationary energy model from semiconductor modelling. We accept the more realistic assumption that the continuity equations for electrons and holes have to be considered only in a subdomain Ω0 of the domain of definition Ω of the energy balance equation and of the Poisson equation. Here Ω0 corresponds to the region of semiconducting material, Ω \ Ω0 represents passive layers. Metals serving as contacts are modelled by Dirichlet boundary conditions. We prove a local existence and uniqueness result for the two‐dimensional stationary energy model. For this purpose we derive a W1,p ‐regularity result for solutions of systems of elliptic equations with different regions of definition and use the Implicit Function Theorem. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The asymmetric hydrosilylation of acetophenone with Ph2SiH2 has been investigated in the presence of (S)-amphos as the chiral ligand in combination with the cyclooctadiene-rhodium(I), -iridium(I), -palladium(II), and -platinum(II) chloride complexes.
High activity and optical yields up to 50% ee have been obtained. The product configuration induced by the rhodium system is (S), in all other cases it was (R). 相似文献
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We consider several tensorial wave equations, specifically the equations of Maxwell, Yang–Mills, and Weyl fields, posed on a curved spacetime, and we establish new energy inequalities under certain one-sided geometric conditions. Our conditions restrict the lapse function and deformation tensor of the spacetime foliation, and turn out to be a one-sided and integral generalization of conditions recently proposed by Klainerman and Rodnianski as providing a continuation criterion for Einstein's field equations of general relativity. As we observe it here for the first time, one-sided conditions are sufficient to derive energy inequalities for certain tensorial equations, provided one takes advantage of some algebraic properties enjoyed by the natural energy functionals associated with the equations under consideration. Our method especially applies to the Bel–Robinson energy for Weyl fields, and our inequalities control the growth of the energy in a uniform way, with implied constants depending on the one-sided geometric bounds, only. 相似文献