1. Department of Textile Engineering, Division of Material Science & Technology, I.L.R.I., Kyung Hee University, Yongin-shi, Kyungki-Do 449-701, Korea; Telecom. R&D Center, Samsung Electronics Co., Ltd., Suwon P.O. Box 105, Kyungki-Do, 440-600 Korea; Division of Polymer Research, Korea Institute of Science and Technology, Cheongryang P.O. Box 131, Seoul, 130-650 Korea; and School of Electrical Engineering, Seoul National University, 151-742 Korea