1. National Institute of Technology (KOSEN) Ariake College 150, Higashihagio‐machi Omuta Fukuoka 836‐8585 Japan
2. Technical Development Department Hokuriku Roka Co., Ltd. 2‐4‐7, Maruyama‐machi Sabae Fukui 916‐0019 Japan
3. Department of Applied Science for Electronics and Materials Kyushu University 6‐1, Kasuga‐koen Kasuga Fukuoka 816‐8580 Japan