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The Chinese government is actively promoting green and low-carbon transformation for economic and social development, especially in the wastewater treatment industry. This article uses regression analysis to study the impact of company R&D input on patent performance and company operating income for different regulatory environments and regions. Companies in the wastewater treatment industries of the Shanghai and Shenzhen stock exchanges from 2013 to 2020 are selected as research samples. The results show that there is a partial mediating effect of patent performance between company R&D input and company operating income; the stimulative effect of company R&D input is strongest in a high external-high internal environment; this stimulative effect is also more significant in the three strategic regions when compared with other regions. The findings suggest that company R&D input can promote company operating income. Thus, wastewater treatment enterprises should establish complete R&D systems to improve their innovative output capabilities. Enterprises in more developed regions should play a leading role in undertaking technological innovation. Furthermore, the government should formulate policies to improve the capacity of companies to conduct wastewater treatment and continue down the road of green development.

The flow field structure and aerodynamic forces of trains with aerodynamic brake in cross-wind after simplifying the train’s model are studied. Three-dimensional Reynolds average N-S equations (RANS) combining k-ω turbulence model is adopted. The SIMPLE method is used to couple the pressure and velocity. Firstly, the train’s flow field’s variation discipline caused by the aerodynamic brake is analyzed. Then the side force, lift force and rollover moment acting on the train with aerodynamic brake and the one without aerodynamic brake are compared on condition of various wind direction angles. The influence of the aerodynamic brake on trains’ aerodynamic forces and derailment coefficient on condition of various wind direction are analysed. It comes to a conclusion that the derailment coefficient of the train with aerodynamic braking is truly increased but only slightly increased and all the derailment coefficients are under 0.8 which satisfy the safety request of the train’s running safety.

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