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931.
We show a set of transformations that allow one to obtain analytical solutions in several quantum-optical problems. We start with the ion-laser (time-dependent) interaction, continue with the problem of a slow atom interacting with a quantized field, and end with a master equation that describes the losses. In all cases, it is shown that one may find useful transformations that simplify the problems. 相似文献
932.
We report variational transition‐state theory calculations for the OH + O3→ HO2 + O2 reaction based on the recently reported double many‐body expansion potential energy surface for ground‐state HO4 [Chem Phys Lett 2000, 331, 474]. The barrier height of 1.884 kcal mol?1 is comparable to the value of 1.77–2.0 kcal mol?1 suggested by experimental measurements, both much smaller than the value of 2.16–5.11 kcal mol?1 predicted by previous ab initio calculations. The calculated rate constant shows good agreement with available experimental results and a previous theoretical dynamics prediction, thus implying that the previous ab initio calculations will significantly underestimate the rate constant. Variational and tunneling effects are found to be negligible over the temperature range 100–2000 K. The O1? O2 bond is shown to be spectator like during the reactive process, which confirms a previous theoretical dynamics prediction. © 2007 Wiley Periodicals, Inc. 39: 148–153, 2007 相似文献
933.
Reaction of α-bromo ketones with 6-amino-2-methylpyrimidin-4(3H)-one under basic conditions and in the presence of atmospheric oxygen affords novel 7-substituted 2-amino-pyrrolo[1,2-a]pyrimidine-4,6-diones that are readily hydrolyzed to afford the corresponding acrylic acid derivatives. The reaction sequence consists of an initial alkylation, followed by an unexpected condensation, elimination, and oxidation sequence to afford the products. This cascade reaction sequence represents a rapid and unprecedented route to the described small molecules. 相似文献
934.
This Letter presents an analysis method for a delay-independent absolute stability of time-delay Lur'e systems with sector and slope restrictions. The proposed method is based on the Lyapunov functions with quadratic form of states and nonlinear functions of the systems. Several criteria are derived in terms of linear matrix inequalities (LMIs). A numerical example is illustrated to show the effectiveness of the proposed method. 相似文献
935.
936.
The syntheses of cyclophosphodiesters of 5-C-(hydroxymethyl)-hexoses and hexitols and of 6-C-(hydroxymethyl)-hexoses are reported, along with that of 6-deoxy-gluco-heptose 7-phosphate. These compounds proved to be reasonable substrate mimics and show inhibitory activity against human d-myo-inositol 3-phosphate synthase. 相似文献
937.
938.
939.
940.
Ju‐Myung Song Mohammad Luqman Joon‐Seop Kim Kwanwoo Shin 《Journal of Polymer Science.Polymer Physics》2007,45(9):1045-1052
The mechanical properties and morphology of homoblends of poly(ethyl acrylate‐co‐acrylate) (PEAA) having one ion pair per ionic monomer repeat unit and poly(ethyl acrylate‐co‐itaconate) (PEAITA) having two ion pairs were investigated. It was found that the compositional variation in the ionomer homoblends did not affect the matrix or cluster glass transition temperatures of the two ionomers of the homoblends. It was also observed that the ionomer homoblends showed two ionic plateaus and that the changes in the two ionic moduli were directly related to the relative amounts of the two ionomers. The ionic moduli calculated with the model for filler‐dispersed materials were found to fit the experimental data to a great extent. Therefore, it was suggested that the PEAITA/PEAA ionomer homoblends were filler‐containing composite materials rather than miscible blends. In the X‐ray scattering study, it was observed that the morphology of the ionomer homoblends was not affected by mixing. The results obtained in this work might be useful for the modification of the storage moduli of copolymers in a certain temperature range without the alteration of their processing temperatures. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1045–1052, 2007. 相似文献