永磁轮毂电机的磁热双向耦合方法研究

分析我国粮食进口及价差驱动特征，并利用门槛回归模型分品种实证检验国内外粮食价差对粮食净进口量的影响，研究发现，我国粮食存在一定程度的过度进口，其根本原因是我国粮食生产成本高、缺乏竞争力；价差不仅对稻谷、小麦和大豆的净进口量变化具有显著影响，且对稻谷和小麦净进口量的影响具有门槛效应；价差对各粮食品种净进口量的影响并不相同，这可能与粮食品种本身的价格水平、贸易状况、贸易政策及国际竞争力等因素密切相关。

Research on Magneto Thermal Coupled Methodology of In Wheel Motor

This paper makes an analysis of grain imports and the driving characteristics of grain spreads in China, and uses threshold regression model to empirical test whether grain spreads at home and abroad will impact the imports respectively. The study finds that the grain imports exceed the domestic demand, because grain production costs in China are higher, and domestic grain lacks of competitiveness. Grain spreads at home and abroad do impact the imports in China. More specifically, the impacts on the net cereal imports have a threshold effect. But the impacts of spreads on the net imports of grain varieties is not the same, which may be closely related to the price level, trade status, trade policy and international competitiveness of grain varieties.