Molecular electric field mapping of some anions and cations of 2- aminopurine and 6- thioguanine

Electric fields of the anions, cations and neutral forms of 2-aminopurine and 6-thioguanine have been mapped. Certain important features of the maps are similar to those found earlier in the neutral and ionic forms of adenine and guanine. The computed electric field patterns satisfactorily explain reactive sites and biological activity of the molecules.     

Photosensitized formation of singlet oxygen by vitamins of the B group

Presented at the XV IUPAC Symposium on Photochemistry, Prague, July 17–22, 1994.     

金催化化学发光新体系——苯并吡喃化学发光分析法测定金矿中的痕量金

本文提出了一种测定矿样中痕量金的化学发光分析法,氯化6,7-二羟基-2,4-二甲基苯并吡喃-H_2O_2化学发光体系,方法的检出限为7ppb。工作曲线线性范围是10～1000ppbAu,测定的相对标准偏差小于7％。应用本法测定矿样中的金,结果良好。     

Analysis of atomic arrangement in magnetic Fe–Pt nanoparticles

The order parameter S of Fe–Pt nanoparticles is estimated from X-ray diffraction (XRD) patterns. The total intensity of a diffraction peak is obtained by Rietveld analysis as well as simply integrating the intensity. The Rietveld analysis is found to provide a plausible value of S even for a sample showing an XRD pattern with broad and overlapped peaks. Another order parameter Q, which is obtained from Mössbauer spectra, is introduced, and it is confirmed that Q is equivalent to the probability of Fe atoms being in the L1₀-type atomic arrangement. The coercivity of Fe–Pt nanoparticles is directly proportional to Q, while it vanishes at S=0.4, indicating that the magnetic property of Fe–Pt nanoparticles has a closer relationship to Q than S.