1. PhD Student, School of Environmental Science and Engineering, Pohang Univ. of Science and Technology, San 31 Hyoja Dong, Pohang 790-784, Korea.
2. PhD, Dept. of Chemical Engineering, Pohang Univ. of Science and Technology, San 31 Hyoja Dong, Pohang 790-784, Korea.
3. Professor, Dept. of Chemical Engineering, Pohang Univ. of Science and Technology, San 31 Hyoja Dong, Pohang 790-784, Korea.