1. Center for Advanced Research of Energy Technology, Hokkaido University, N13, W8, Kita-ku, Sapporo 060-8628, Japan
2. Hokkaido National Industrial Research Institute, 2-17, Tsukisamu-Higashi, Toyohira-ku, Sapporo 062, Japan
3. Graduate School of Engineering, Kyushu University, Fukuoka 812-8581, Japan