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101.
Differential cross sections are calculated for positron-hydrogen-molecule scattering below the positronium formation threshold usingK-matrix elements obtained by the Kohn variational method. The internuclear separation of the hydrogen molecule is fixed at its equilibrium value, 1.4a0. The trial function used in the Kohn calculation is very flexible. It contains separable and Hylleraas-type basis functions and also basis functions to take into account longrange polarization. The cross sections for rotational excitation are also calculated, using the adiabatic-rotation approximation. Preliminary results are presented in this paper; full details will be published elsewhere. 相似文献
102.
Electron spin resonance analysis of superoxide anion radical scavenging activity with spin trapping agent, diphenyl-PMPO. 总被引:1,自引:0,他引:1
Recently, a novel electron spin resonance (ESR) spin-trapping agent, 2-(diphenylphosphinoyl)-2-methyl-3,4-dihydro-2H-pyrrole N-oxide (Diphenyl-PMPO), was synthesized. Because it had some advantages in stability and reactivity over conventional spin-trapping agents, we applied it to the ESR analyses of superoxide anion radical scavenging activity (SOSA) of superoxide dismutase (SOD) and of well-known natural antioxidants (green tea, oolong tea, and red wine). At the same time, the results with Diphenyl-PMPO were compared with 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Our results revealed that Diphenyl-PMPO showed higher detectability than DMPO in the SOSA assays of SOD and natural antioxidants, so it could be available for the ESR analyses as an alternative to conventional spin-trapping agents. 相似文献
103.
The electrooxidation of alcohols in an aqueous disperse system with N-oxyl-immobilized poly(p-phenylene benzobisthiazole) network polymer particles (PBZTNT-N-Oxyl) as a disperse phase was performed successfully in a simple beaker-type undivided cell under a constant current condition to afford the corresponding ketones, aldehydes, and/or carboxylic acid in moderate to good yields. Recycle use of both the PBZTNT-N-Oxyl particles and the aqueous media could be achieved successfully by immobilization of additional N-oxyl moiety on the polymer particles in an appropriate interval. Notably, the shape and the particle size of PBZTNT-N-Oxyl were not appreciably changed even after 60 times recycle use. 相似文献
104.
Yanagisawa M Shimamura T Iida D Matsuo JI Mukaiyama T 《Chemical & pharmaceutical bulletin》2000,48(11):1838-1840
The crossed aldol reaction of enol esters, which are weak carbon nucleophiles, with aldehydes was effectively carried out under mild conditions by using a catalytic amount of several cationic species paired with tetrakis(pentafluorophenyl)borate. 相似文献
105.
T Hayashi M Shimamura F Matsuda Y Minatogawa H Naruse Y Iida 《Journal of chromatography. A》1986,383(2):259-269
Sensitive methods for the determination of deuterated and non-deuterated tryptophan, tryptamine and serotonin by combined capillary gas chromatography and negative ion chemical ionization mass spectrometry were developed. [3,3-2H2]-L-Tryptophan, which was used as a tracer, was synthesized for studies of their in vivo metabolism. Tryptophan was converted into its trifluoroacetylmethyl derivative after prepurification with an AG 50W-X2 cation-exchange column. Tryptamine and serotonin were extracted with 20% butanol in diethyl ether and derivatized with trifluoroacetic anhydride. These derivatives were separated and determined by selected ion monitoring. In these determinations, [2',3,3,4',5',6',7'-2H7]-D,L-tryptophan, [alpha,alpha,beta,beta-2H4]tryptamine and [alpha,alpha,beta,beta-2H4]serotonin were used as internal standards. 相似文献
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