[1] Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA
[2] Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USA
[3] Air Force Res Lab, Aerosp Syst Directorate, Wright Patterson AFB, OH 45433 USA
[4] Hefei Univ Technol, Sch Mat Sci & Engn, Hefei 230009, Anhui, Peoples R China