1. School of Materials Science and Engineering; South China University of Technology; Guangzhou 510640 China
2. Laboratory for Advanced Fibers; Empa; Swiss Federal Laboratories for Materials Science and Technology; Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
3. Center for X-ray Analytics; Empa; Swiss Federal Laboratories for Materials Science and Technology; Ueberlandstrasse 129 8600 Dübendorf Switzerland