1. College of Environmental Science and Applied Chemistry (BK 21), Kyunghee University, Kyungki 449-701, Korea, Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-2-dong, Songpa-gu, Seoul 138-736, Korea, and Department of Chemistry, Inha University, 253 Yonghyundong Namgu, Inchon 402-751, Korea