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941.
942.
C Fernandez B Baune F Gimenez A Thuillier R Farinotti 《Journal of chromatography. A》1991,572(1-2):195-202
The enantiomers of zopiclone were determined in human plasma using a sequential achiral-chiral liquid chromatographic method. Zopiclone was separated from the biological matrix and quantified on an achiral silica column. The limit of detection was 5 ng/ml. The eluent fraction containing zopiclone was collected, evaporated, reconstituted with the mobile phase and injected onto a chiral cellulose carbamate column where the enantiomeric ratio was calculated. This validated method, applied to a pilot study, suggests that pharmacokinetics of zopiclone is stereoselective. 相似文献
943.
In this paper, a multiple-objective linear problem is derived from a zero-sum multicriteria matrix game. It is shown that the set of efficient solutions of this problem coincides with the set of Paretooptimal security strategies (POSS) for one of the players in the original game. This approach emphasizes the existing similarities between the scalar and multicriteria matrix games, because in both cases linear programming can be used to solve the problems. It also leads to different scalarizations which are alternative ways to obtain the set of all POSS. The concept of ideal strategy for a player is introduced, and it is established that a pair of Pareto saddle-point strategies exists if both players have ideal strategies. Several examples are included to illustrate the results in the paper. 相似文献
944.
945.
Single crystals of poly(p-xylylene) were grown in dilute α-methylnaphthalene solution and studied by bright-field and high-resolution electron microscopy (HREM). The crystallization process was discussed in terms of the dependence of crystal form on crystallization conditions. A 0.15 nm resolution was achieved from high-resolution images of a frozen liquid crystalline phase. High-temperature electron diffraction patterns confirmed the existence of the liquid-crystalline phase in agreement with previous work of Lieser. The HREM images show the molecular packing in the smectic B phase. © 1992 John Wiley & Sons, Inc. 相似文献
946.
947.
Edwin JaoStephane Bogen Anil K SaksenaViyyoor Girijavallabhan 《Tetrahedron letters》2003,44(27):5033-5035
Unsaturated lactam derived from (S)-pyroglutaminol undergoes a totally stereoselective cycloaddition reaction with (2-(acetoxymethyl)-3-allyl)trimethylsilane in the presence of Pd(P(OiPr)3)4 in refluxing toluene. This step was efficiently used to introduced the 5,5-fused framework desired for the preparation of novel proline surrogates. 相似文献
948.
Edwin Langmann 《Communications in Mathematical Physics》2004,247(2):321-351
We construct a quantum field theory model of anyons on a circle and at finite temperature. We find an anyon Hamiltonian providing a second quantization of the elliptic Calogero-Sutherland model. This allows us to prove a remarkable identity which is a starting point for an algorithm to construct eigenfunctions and eigenvalues of the elliptic Calogero-Sutherland Hamiltonian.Work supported by the Swedish Natural Science Research Council (NFR). 相似文献
949.
Electron pulse radiolysis at ?298°K of 2 atm H2 containing 5 torr O2 produces HO2 free radical whose disappearance by reaction (1), HO2 + HO2 →H2O2 + O2, is monitored by kinetic spectrophotometry at 230.5 nm. Using a literature value for the HO2 absorption cross section, the values k1 = 2.5×10?12 cm3/molec·sec, which is in reasonable agreement with two earlier studies, and G(H) G(HO2) ?13 are obtained. In the presence of small amounts of added H2O or NH3, the observed second-order decay rate of the HO2 signal is found to increase by up to a factor of ?2.5. A proposed kinetic model quantitatively explains these data in terms of the formation of previously unpostulated 1:1 complexes, HO2 + H2O ? HO2·H2O (4a) and HO2 + NH3? HO2·NH3 (4b), which are more reactive than uncomplexed HO2 toward a second uncomplexed HO2 radical. The following equilibrium constants, which agree with independent theoretical calculations on these complexes, are derived from the data: 2×10?20?K4a?6.3 × 10?19 cm3/molec at 295°K and K4b = 3.4 × 10?18 cm3/molec at 298°K. Several deuterium isotope effects are also reported, including kH/kD = 2.8 for reaction (1). The atmospheric significance of these results is pointed out. 相似文献
950.