1. a Department of Polymer Chemistry , Faculty of Engineering Kyoto University , Kyoto , Japan
2. b Research Laboratory, Mitzubishi Rayon Co., Ltd. , Ohtake, Hiroshima-ken , Japan
3. c Research and Development Department , Matzushita Denko Co., Ltd. , Kadoma, Osaka-fu , Japan
4. d Non-metalic Materials Division, Toyota Motors Co., Ltd. , Toyota, Aichi-ken, Japan