1. Program
of Materials Science and Engineering, University of California—San Diego, La Jolla, California 92093-0418, United States
2. Department
of Structural Engineering, University of California—San Diego, La
Jolla, California 92093-0085, United States
3. Department
of NanoEngineering, University of California—San Diego, La Jolla, California 92093-0448, United States