Papers by Author: Yoshihide Honda

Abstract: Annihilation process of positron in Nafion-117 was investigated under several kinds of conditions to elucidate degradation process of polymer electrolyte membrane. It was found that ortho-positronium stayed beside cluster wall and side chains and its lifetime reflected cluster size. Annihilation process of positron was found to be greatly influenced by the electronic state of sulfonic group. These results showed that positron annihilation spectroscopy would be good tool to detect degradation of polymer electrolyte membrane.

Abstract: An interlaboratory comparison for positron annihilation lifetime (PAL) measurements for pure nickel and fused silica was performed. Based on the reported positron (for nickel) and positronium (for fused silica) lifetimes, the uncertainties in the PAL measurements were estimated.

Abstract: Positron annihilation techniques were applied for irradiated Nafion-117 to investigate deterioration process in PEM. There were no significant changes in lifetime of positron/positronium, whereas the S-parameter showed fairly good correlation with proton conductivity.