1. Corporate Research & Development Asahi Kasei Corporation, 2-1 Samejima, Fuji, Shizuoka 416-8501, Japan
2. Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi 755-8611, Japan
3. Faculty of Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi 755-8611, Japan