1. 1Technical R&D Center, Hankook Tire Mfg. Co. Ltd., 23-1 Jang Dong, Yusung-Ku, Tae Jeon 306-343, Korea
2. 2Department of Materials Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-Ku, Kyoto 606, Japan
3. 3School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang, Malaysia
4. 4Institute for Chemical Research, Kyoto University, Uji, Kyoto 611, Japan