1. Department of Materials Science
and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon
305-701, Republic of Korea
2. Graduate School of EEWS (WCU), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu,
Daejeon 305-701, Republic of Korea
3. Department of Materials Science
and Engineering, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea