1. Ballard Power Systems, 9000 Glenlyon Parkway, Burnaby, British Columbia V5J 5J8, Canada.
2. Business Development Department, Nisshinbo Holdings Inc., 1-2-3 Onodai, Midori-ku, Chiba 267-0056, Japan.
3. Division of Environmental Engineering Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
4. International Research and Education Center for Element Science, Faculty of Science and Technology, Gunma University, Gunma 376-8515, Japan.