1. a Polymer/Bio-Composites Research Lab, Department of Polymer Science and Engineering, Kumoh National Institute of Technology, Gumi, Gyungbuk 730-701 Korea
2. b Polymer/Bio-Composites Research Lab, Department of Polymer Science and Engineering, Kumoh National Institute of Technology, Gumi, Gyungbuk 730-701 Korea
3. c Nano Materials Center, Korea Institute of Energy Research, Daejeon 305-343, Korea