1. Department of Chemical & Biomolecular Engineering, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea
2. Advanced Materials Division, KRICT, Sinseongno 19, Yuseong-gu, Daejeon 305-600, Korea
3. R&D Center, SK Energy, 140-1 Wonchon-dong, Yuseong-gu, Daejeon 305-712, Korea