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131.
Wormer PE Kłos JA Groenenboom GC van der Avoird A 《The Journal of chemical physics》2005,122(24):244325
The two four-dimensional diabatic potential energy surfaces (DPESs) for OH-HCl are computed that correlate with the twofold degenerate (2)Pi ground state of the free OH radical. About 20 000 points on the surface are obtained by the ab initio coupled-cluster and multi-reference configuration interaction methods. Analytic forms for the diabatic potential energy surfaces are derived as expansions in complete sets of orthogonal functions depending on the three intermolecular angles. The numeric computation of the angular expansion coefficients is discussed. The distance-dependence of the angular coefficients is represented by the reproducing kernel Hilbert space method. It is checked that both diabatic potentials converge for large intermolecular separations to the values computed directly from the electrostatic multipole expansion. The final DPESs are discussed and illustrated by some physically meaningful one- and two-dimensional cuts through them. 相似文献
132.
A rapid combustion technique for the determination of small amounts of sulphur and halogens in organic liquids is described. The technique, in the first instance, refers to the Shell-Braun quartz tube combustion unit and offers an appreciable extension of the working area of this apparatus. 相似文献
133.
Cees van Dijk Johan W. van Leeuwen Cees Veeger Jan P.G.M. Schreurs Embrecht Barendrecht 《Journal of Electroanalytical Chemistry》1982,141(6):743-759
This paper reports on a pulse polarographic study of low-potential electron-transferring proteins at the mercury electrode ★. The proteins studied were the negatively charged iron—sulphur cluster containing ferredoxins from spinach, and from Megasphaera elsdenii, the iron-containing rubredoxin and the FMN-containing flavodoxin both from M. elsdenii. Furthermore, the positively charged, four haem-containing cytochrome c3 from Desulfovibrio vulgaris strain Hildenborough was studied. It was observed that the electrode reaction of these proteins could be made much more efficient when a polymer or surfactant was added, with a charge opposite to the protein. The reduction efficiency of these proteins reaches an optimum when the net charge of the protein times its concentration is about equal to the same amount of opposite charges, which was added as a polymer or surfactant. 相似文献
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135.
Gerrit L'abb Maria Bruynseels Pieter Delbeke Suzanne Toppet 《Journal of heterocyclic chemistry》1990,27(7):2021-2027
The two structural isomers, 4 and 5 , of 1-substituted-4-iminomethyl-1,2,3-triazoles are interconvertible when heated in dimethyl sulfoxide at 80°. The equilibrium position depends on the electronic properties of the R-substituent, favoring 5 for R = alkyl, benzyl and anisyl, and 4 for p-chlorophenyl and p-nitrophenyl. An interesting application is the synthesis of 1-alkyl-1,2,3-triazole-4-carbaldehydes from 1-phenyl-1,2,3-triazole-4-carbaldehyde by Scheme I. The hydrazones 4ij and the oxime 4k do not rearrange due to an unfavorable Z-configuration around the C ? N bond, whereas the acyloximino derivative 4m is converted into the nitrile 11 . The structures of the products have been fully characterized by 13C nmr spectroscopy and the mechanistic details of the rearrangement are discussed. 相似文献
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138.
Juan F. Vega Denka G. Hristova Gerrit W. M. Peters 《Journal of Thermal Analysis and Calorimetry》2009,98(3):655-666
We investigated the effect of flow in combination with molecular architecture on crystallization for linear and branched polypropylenes
by means of dynamical mechanical spectroscopy. Compared to the linear polymer, the branched one exhibits much slower relaxation
after deformation, causing higher levels of molecular orientation and molecular stretch for the same flow conditions. Different
regimes of flow-induced crystallization are observed as a function of an increased level of molecular orientation and stretch.
These regime changes cause the structure development in the material to vary from 3-dimensional spherulitical growth to nearly
1-dimensional fiber-like growth. Intermediate behavior is observed when the flow is strong (for the linear polymer) or weak
enough (for the branched polymer), or in time when the effect of flow is exhausting. It is important to note that dynamical
mechanical measurements can be used to probe different aspects of the (flow induced) crystallization process, such as a relative
level of crystallinity and timescales of the evolution, but do not give absolute values. A correlation is found with the level
of crystallinity obtained from real-time WAXS measurements and the kinetics of linear viscoelastic properties, but this correlation
is not unique and depends on the pre-shear conditions applied. 相似文献
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