[1] Lanzhou Univ Technol, Coll Mat Sci & Engn, Lanzhou 730050, Peoples R China
[2] Lanzhou Univ Technol, Coll Mechanoelect Engn, Lanzhou 730050, Peoples R China
[3] Chinese Acad Sci, Tech Inst Phys & Chem, Key Lab Cryogen, Beijing 100190, Peoples R China