1. School of Materials Science & EngineeringNorth Minzu University Yinchuan 750021 P. R. China
2. Key Lab. of Powder Material & Advanced CeramicsNorth Minzu University Yinchuan 750021 P. R. China
3. International Scientific & Technological Cooperation Base of Industrial Waste Recycling and Advanced MaterialsNorth Minzu University Yinchuan 750021 P. R. China
4. Center for Joint SurgerySouthwest Hospital Third Military Medical University (Army Medical University) Chongqing 400038 P. R. China
5. School of Chemistry & Chemical EngineeringNorth Minzu University Yinchuan 750021 P. R. China