1. Department of Materials Science and Engineering; Frederick Seitz Materials Research Laboratory; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
2. Department of Materials Science and Engineering; Department of Energy Engineering; Hanyang University; Seoul 133-791 Republic of Korea
3. Department of Mechanical Engineering; Civil and Environmental Engineering; Center for Engineering and Health, and Skin Disease Research Center; Northwestern University; Evanston IL 60208 USA
4. AML, Department of Engineering Mechanics; Center for Mechanics and Materials; Tsinghua University; Beijing 100084 China
5. Functional Materials and Microsystems Research Group; School of Electrical and Computer Engineering; RMIT University; Melbourne VIC 3000 Australia