1. Metals and Materials Engineering Department, Sun Moon University, 100, Kalsan-ri, Asan 336-708, South Korea e-mail:
2. Mechanical Engineering Department, Sun Moon University, 100, Kalsan-ri, Asan 336-708, South Korea e-mail:
3. Metals and Materials Engineering Department, Sun Moon University, 100, Kalsan-ri, Asan 336-708, South Korea;
4. Environmental Engineering Department, Sun Moon University, 100, Kalsan-ri, Asan 336-708, South Korea e-mail: