1. Analytical Engineering Laboratory of Samsung Advanced Institute of Technology, P.O. Box 111, Suwon 440-600, Korea
2. Department of Mechanical Engineering, Soongsil University, Seoul 06978, Korea
3. School of Electronics and Information Engineering, Korea Aerospace University, Goyang-si 10540, Korea
4. Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea