1. Nano-Electro Mechanical Device Laboratory
2. School of Mechanical Engineering
3. Yonsei University
4. Seoul 120-749
5. South Korea
6. Department of Electrical Engineering
7. Sejong University
8. Gwangjin-gu
9. Department of Mechanical and Aerospace Engineering
10. University of California Irvine
11. Irvine
12. USA