1. Department of Electrical Engineering, Faculty of Engineering, Sanyo-onoda City University, 1-1-1, Daigaku-Dori, Sanyo-Onoda, Yamaguchi 756-0884, Japan
2. Department of Applied Chemistry, Faculty of Engineering, Sanyo-onoda City University, 1-1-1, Daigaku-Dori, Sanyo-Onoda, Yamaguchi 756-0884, Japan