1. Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, 599, Gwanangno, Gwanak-gu, Seoul 151-744, Republic of Korea
2. Department of Mechanical and Aerospace Engineering of Seoul National University, 599, Gwanangno, Gwanak-gu, Seoul 151-744, Republic of Korea
3. Green Growth Technology Laboratory, Korea Electric Power Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejeon 305-760, Republic of Korea