North China University of Water Resources and Electric Power, affiliation not provided to SSRN, North China University of Water Resources and Electric Power, North China University of Water Resources and Electric Power, North China University of Water Resources and Electric Power, North China University of Water Resources and Electric Power, Tongji University, North China University of Water Resources and Electric Power, North China University of Water Resources and Electric Power, North China University of Water Resources and Electric Power and Henan Agricultural University