1. Department
of Environmental Science and Engineering, Ewha Womans University, Seoul, 120-750, Korea
2. Department
of Physics and Science of Advanced Materials Program, Central Michigan University, Mt.
Pleasant, Michigan 48859, United States
3. Department
of Physics and Vitreous State Laboratory, The Catholic University, Washington, DC 20064, United States
4. School
of Mechanical Engineering, Yonsei University, Seoul, 120-749, Korea
5. Department
of Applied Physics, College of Applied Science, Kyung Hee University, Yongin-si,
Giheung-gi, Gyeonggi-do 446-701, Korea