1. Department of Materials Science Engineering, Hanyang University, Seoul 133-791, Korea
2. Departments of Civil and Environmental Engineering and Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, United States
3. Energy Lab, Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Suwon 440-600, Korea
4. Department of Materials Science and Engineering, University of Illinois at Urbana—Champaign, Urbana, Illinois 61801, United States
5. WCU Department of Energy Engineering, Hanyang University, Seoul 133-791, Korea