某A00级纯电动汽车动力系统选型及仿真分析

在纯电动汽车的开发过程中,动力系统的选型对整车动力经济性及整车成本至关重要。以某A00级纯电动汽车作为研究对象,通过理论计算得出整车需要匹配的动力系统边界。随后利用Cruise软件建立仿真模型并进行仿真,通过仿真结果与整车动力经济性能指标对比来验证动力系统的选型合理性。     

Causality of future and spot grain prices between China and the US: Evidence from soybean and corn markets against the surging import pressure

As the boom of the world grain market phases out, the challenge for Chinese government has gradually moved from retarding grain exports to restraining imports. This study tries to examine the causalities of soybean and corn price movement among the United States (US) future market, Chinese domestic future market and Chinese spot markets. We find that the daily prices of all these three types of grains belong to I(1) series, and there are long-run integrations. Also Chinese soybean future prices adjust more quickly than its spot prices, while Chinese corn future prices adjust slower. This paper finds that the soybean price movement originates from the US future market, then passes through Chinese future market, and finally reaches Chinese spot market, while the corn price movement starts in Chinese spot market, then spreads to the future markets in both China and the US. Finally, this paper also provides some policy implications on how to release the pressure from the grain imports.