[1] Andong Natl Univ, Sch Mech Engn, Andong 760749, Kyungbuk, South Korea
[2] Andong Natl Univ, Dept Mech Design Engn, Grad Sch, Andong 760749, Kyungbuk, South Korea
[3] Korea Electrotechnol Res Inst, Appl Superconduct Res Ctr, Chang Won 641120, Kyungnam, South Korea