1. Nanomechanical Systems
Research
Division, Korea Institute of Machinery and Materials, Daejeon 305-343, Republic of Korea
2. Department of Nanomechatronics, University of Science and Technology, Daejeon 305-350,
Republic of Korea
3. Graduate
School of Nanoscience
and Technology (WCU), KAIST, Daejeon 305-701,
Republic of Korea