1. Department of Materials Science and Engineering, Tokyo Institute of Technology, Mail Box S8-27, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan
2. Shinwa Corporation, 1-32-2 Honcho, Nakano-ku, Tokyo 164-0012, Japan
3. Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan