宁波市科技计划项目No.2013A610190;国家自然科学基金项目No.41371205;宁波科技计划软科学项目No.2013A10096 Supported by the Science and Technology Project of Ningbo Municipality No.2013A610190,the National Natural Science Foundation of China No.41371205 and the Soft Science Project of Ningbo Municipality No.2013A10096