1. Assistant Professor, Dept. of Chemical Engineering, Hankyong National Univ., 67 Sukjong-Dong, Ansung City, Kyonggi-Do 456-749, Korea.
2. Graduate Student, Dept. of Chemical Engineering, Sogang Univ., C.P.O. Box 1142, Seoul 100-611, Korea.
3. Associate Professor, Dept. of Chemical Engineering, Cheju National Univ., Ara-Dong, Cheju City, Cheju-Do 690-756, Korea.
4. Professor, Dept. of Chemical Engineering, Sogang Univ., C.P.O. Box 1142, Seoul 100-611, Korea.