1. Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, Korea
2. Materials Processing Division, Korea Institute of Materials Science, Changwon, 641-010, Korea
3. Department of Polymer Engineering, Division of Applied Chemical Engineering, Pukyong National University, Busan 608-739, Republic of Korea
4. Department of Physics, Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea