1. The State Key Lab of High Performance Ceramics and Superfine MicrostructureShanghai Institute of CeramicsChinese Academy of Sciences Shanghai 200050 P. R. China
2. Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Department of Medical UltrasoundShanghai Tenth People's HospitalUltrasound Research and Education InstituteTongji University Cancer CenterTongji University School of Medicine Shanghai 200072 P. R. China