LI Xiaochun | Department of Economics, Nanjing University. The authors express thanks to the anonymous referee for the constructive suggestions and comments. This article is sponsored by the National Social Sciences Fund Project No. 10BJL035 and Key Project of 2009 f

Department of Electronic Engineering, Shanghai Jiaotong University

Department Of Electronic Engineering Shanghai Jiaotong University

Department of Economics, Nanjing University. The authors express thanks to the anonymous referee for the constructive suggestions and comments. This article is sponsored by the National Social Sciences Fund Project No. 10BJL035 and Key Project of 2009 f

Department Of Cardiology An Zhen Hospital Capital Medical University

Department Of Anatomy Medical Center Of Fudan University

Department Of Electronic Engineering Shanghai Jiao Tong University

Department Of Electronic Engineering Shanghai Jiaotong University

Department of Electronic Engineering, Shanghai Jiaotong University

Department Of Electronic Engineering Shanghai Jiaotong University

Department of Economics, Nanjing University. The authors express thanks to the anonymous referee for the constructive suggestions and comments. This article is sponsored by the National Social Sciences Fund Project No. 10BJL035 and Key Project of 2009 f