2008年 Analysis of Radiation Induced Phenomena in a Polymer Electrolyte Membrane with Positron Annihilation Technique 9th International Workshop on Positron and Positronium Chemistry, Y. Honda, N. Kimura, P. K. Pujari, G. Isoyama, and S. Tagawa, H. Miyauchi, Y. Shibahara, Y. Akiyama, Y. Izumi, and S. Nishijima