1. Ph.D. Candidate, Research Institute of Structural Engineering and Disaster Reduction, Tongji Univ., Shanghai 200092, China.
2. Professor, Dept. of Mechanical Engineering, Univ. of California, Santa Barbara, CA 93106.
3. Assistant Professor, Research Institute of Structural Engineering and Disaster Reduction, Tongji Univ., Shanghai 200092, China (corresponding author).
4. Professor, Dept. of Physics, Univ. of California, Santa Barbara, CA 93106.
5. Professor, Research Institute of Structural Engineering and Disaster Reduction, Tongji Univ., Shanghai 200092, China.