1. Key Laboratory of Analytical Science and Technology of Hebei Province College of Chemistry & Environmental Science Hebei University Baoding Hebei 071002 P. R. China
2. Institute for Superconducting & Electronic Materials School of Mechanical, Materials and Mechatronics Engineering University of Wollongong Wollongong NSW 2522 Australia
3. Fengfan Company Limited Baoding Hebei 071057 P. R. China