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991.
Knaup JM Köhler C Frauenheim T Blumenau AT Amkreutz M Schiffels P Schneider B Hennemann OD 《The journal of physical chemistry. B》2006,110(41):20460-20468
We calculate the minimum energy paths and reaction energies of the adsorption of the epoxide adhesive components diglycidylesterbisphenol A (DGEBA), diethyltriamine (DETA), and the adhesion promoter 3-aminopropylmethoxysilane (AMEO) at two different sites on a model of the native Al2O3 surface, using the nudged elastic band algorithm in conjunction with self-consistent charge-density functional based tight binding. Our results show that the chosen combination of methods is well suited to obtain an overview of the reaction mechanisms and kinetics of the adsorption of organic molecules on inorganic surfaces. The obtained MEP-s show that there is preference for the adsorption of the adhesion promoter, AMEO, over the resin, DGEBA, while the adsorption of the curing agent, DETA, is unfavorable. Our approach also gives an insight into the ranges of the mechanical and electronic influences of the adsorption process on the interface, which neither full ab initio methods nor force field approaches can provide. These results will help to develop a quantum mechanics-molecular mechanics multiscale embedding scheme for more detailed studies of organic/inorganic hybrid interface reactions. 相似文献
992.
López-Pastor M Ayora-Cañada MJ Valcárcel M Lendl B 《The journal of physical chemistry. B》2006,110(22):10896-10902
Water and methanol associations in ionic liquids (ILs) have been studied by means of FTIR spectroscopy. Spectra at different concentrations of water or methanol in ILs were obtained by means of on-line dilution using a flow injection analysis system. Spectral features in the OH stretching region revealed that most of the water and methanol molecules tended to be isolated from each other and to interact with the anion of the IL via H bonding. By means of two-dimensional correlation spectroscopy, the formation of methanol and water dimers was also detected. Multivariate curve resolution was used to recover pure spectra and concentration profiles of the different species. Methanol dimers form at concentrations higher than 0.8% (w/w) in the three studied ILs, 1-ethyl-3-methylimidazolium tetrafluoroborate (emimBF4), 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4), and 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6). Self-association of water molecules takes place in emimBF4 and bmimBF4 at a molar ratio similar to that of methanol molecules; however, water dimers cannot be detected in bmimPF6, the most hydrophobic IL studied. No evidence was found that bigger water clusters are formed in these ILs at the studied cosolvent concentrations. 相似文献
993.
Bernhard von Ludwig 《Mathematische Annalen》1916,77(3):362-389
Ohne Zusammenfassung 相似文献
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Extremal Rational Functions on Symmetric Discrete Sets and Superlinear Convergence of the ADI Method
There is a very fruitful interaction between numerical linear algebra and logarithmic potential theory. For instance, we may
describe weak asympotics for a polynomial extremal problem occurring in the convergence analysis of conjugate gradients (CG)
or of Ritz values; here the link with a constrained minimal energy problem allows to quantify the effect of superlinear convergence. 相似文献
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