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We report the result of the study on the oxygen stoichiometry in Y1:2:3 superconducting systems by the positron experiment. The correlations between local electron density n e and the oxygen stoichiometry and Tc have been directly given, which indicates that n e has a strong dependence on the oxygen stoichiometry and the anomalous changes were found near O T transition. The results proved that there generially exists a electronic weak localization in a tetragonal phase.

We present positron lifetime data of YBa 2 Cu 3 O 6+ x (x=0.92, 0.43) compounds for different photo-irradiation time. It is given that change of the local electron density and vacancy concentration with photoirradiation time. It is found that there is transform at the electronic structure of CuO chains. We also have discussed the effect of photoirradiations time on the electronic structure of YBa 2 Cu 3 O 6+ x systems and their charge reservoir layer and CuO 2 plane conduction.layer. The positron experimental results support the model of photoinduced oxygen-diffusion mechanism.

Na2 1 1At and2 1 1At−Te colloid injections were prepared. By comparison with tissue distribution of Na2 1 1At and2 1 1At−Te colloid injections it has been demonstrated that the2 1 1At−Te colloid is stable in vivo. It has been shown that the radiohalogen,2 1 1At, has huge and extensive radiobiological effects in studying on the changes in histopathology, enzyme histochemistry, chromosome aberration, micronucleus frequency of bone-marrow polychromatic erythrocytes and the injury effect of2 1 1At on experimental Ehrlich ascites cells.