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Heinrich Trischler Thomas Höchfurtner Martin Ruff Christian Paulik 《Kinetics and Catalysis》2013,54(5):559-565
The influence of the concentration of the co-catalysts triethylaluminium (TEAL), tri-iso-butylaluminium (TIBAL), tri-n-octylaluminium on the polymerization rate for standard Ziegler-Natta catalyst systems was studied. By comparing the influence of monomeric TIBAL with TEAL co-catalyst on the polymerization activity, the effect of TEAL dimerization was described. The use of the Eley-Ridealadsorption model instead of Langmuir-Hinselwood model is proposed for the absorption of monomeric aluminiumalkyl species and for the formation of active centers C*. It is further proposed that steric hindrance from different co-catalysts, which results in a higher molecular weight (MW) of polymers, is caused by active centers with reduced space for chain transfer reactions. 相似文献
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A mass conservative well‐balanced reconstruction at wet/dry interfaces for the Godunov‐type shallow water model
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This paper presents a novel mass conservative, positivity preserving wetting and drying treatment for Godunov‐type shallow water models with second‐order bed elevation discretization. The novel method allows to compute water depths equal to machine accuracy without any restrictions on the time step or any threshold that defines whether the finite volume cell is considered to be wet or dry. The resulting scheme is second‐order accurate in space and keeps the C‐property condition at fully flooded area and also at the wet/dry interface. For the time integration, a second‐order accurate Runge–Kutta method is used. The method is tested in two well‐known computational benchmarks for which an analytical solution can be derived, a C‐property benchmark and in an additional example where the experimental results are reproduced. Overall, the presented scheme shows very good agreement with the reference solutions. The method can also be used in the discontinuous Galerkin method. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Dietrich Gudat Martin Schrott 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Examples for 2-D shift correlations between 31P and another heteronucleus via nX-detected 2D-INJZPT or 31P-detected HMQC experiments are presented. The former technique is best suited for 31P, 15N correlations and permits the determination of intramolecular connectivities as well as of relative signs of couplings.1 The “inverse” HMQC expenment allows easy recording of the 77Se NMR spectrum of an equilibrium mixture of 2 and 33, disregarding the severe exchange broadening of the 77Se-resonances 相似文献