1. Department
of Chemistry and BK21+ Program Research Team, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea
2. Department
of Chemistry, Chonnam National University, Gwangju 500-757, Republic of Korea
3. Department
of Chemistry Education, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea