1. Collaborative Center for Nanotech Fibers, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan
2. Department of Functional Machinery and Mechanics, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan
3. Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716