1. Contribution from Toyota Central R&D Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan, Korea Institute of Ceramic Engineering and Technology, Seoul, 153-801, Korea, Graduate School of Engineering, Nagoya University, Nagoya, Aichi, 464-8603, Japan, and CREST-JST, Kawaguchi, Saitama, 332-0012, Japan