1. Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku,
Daegu 702-701, Korea
2. Graduate
School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101,
Japan
3. Department of Materials
Science and Engineering, Graduate School of Engineering, University of Fukui, Bunkyo, Fukui 910-8507, Japan
4. Department of Chemistry, Yeungnam University, Kyoungsan City, Kyoung-buk 712-749,
Korea