1. Department of Materials Science & Engineering, Korea Advanced Institute of Science & Technology, 373-1,
Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea
2. Korea Research Institute of Standards and Science, P.O. Box 102, Yuseong-gu,
Daejeon 305-340, Republic of Korea
3. Electrochemical Engine Center (ECEC) and Departments of Materials
Science and Engineering and Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania
16802, United States