国家自然科学基金41001364;重庆市自然科学基金CSTC 2011jjA00025;中央高校基本科研业务费科研专项CDJZR12190007@@@@National Natural Science Foundation of China No.41001364;Natural Science Foundation of ChongqingNo.CSTC 2011jjA00025;the Fundamental Research Funds for the Central Universities CDJZR12190007