[1] Univ Houston, Dept Phys, Houston, TX 77004 USA
[2] Univ Houston, Texas Ctr Superconduct, Houston, TX USA
[3] Univ Houston, Dept Mech Engn, Houston, TX USA
[4] Harbin Inst Technol, Natl Key Lab Precis Hot Proc Met, Harbin 150001, Peoples R China
[5] Harbin Inst Technol, Sch Mat Sci & Engn, Harbin 150001, Peoples R China