1. College
of Physics and Lab of New Fiber Materials and Modern Textile, Growing
Base for State Key Laboratory, Qingdao University, Qingdao 266071, China
2. Department of Materials Science/CENIMAT-I3N,
Faculty of Sciences and Technology, New University of Lisbon and CEMOP-UNINOVA, Campus de Caparica, 2829-516 Caparica, Portugal