1. Contribution from the Toyota Central R&D Laboratories, Inc., Nagakute, Aichi 480-1192, Japan, Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5, Takayama, Ikoma, Nara 630-0192, Japan, and Department of Chemical Engineering, Nara National College of Technology, 22 Yata-cho, Yamatokoriyama, Nara 639-1080, Japan