Key Program of the National Natural Science Foundation of China, No.71433008; Key Research Program of the Chinese Academy of Sciences, No.KZZD-EW-06-04; National Natural Science Foundation of China, No.41271174; National Key Technology R&D Program, No.2012BAI32B06; Beijing Planning of Philosophy and Social Science, No. 13CSC011
China has been experiencing an unprecedented urbanization process. In 2011, China's urban population reached 691 million with an urbanization rate of 51.27%. Urbaniza- tion level is expected to increase to 70% in Chi...