Water splitting is an important approach for energy conversion to obtain hydrogen and oxygen. Apart from solar water splitting, electrochemical method plays a key role in the booming field, and it is urgent to develop...Water splitting is an important approach for energy conversion to obtain hydrogen and oxygen. Apart from solar water splitting, electrochemical method plays a key role in the booming field, and it is urgent to develop novel and efficient catalysts to accelerate water splitting reaction. Recently, newly emerging self-supported materials, especially three dimensional（3D） carbon substrate electrochemical catalysts, have attracted great attention benefiting from their fantastic catalytic performances, such as large surface area,enhanced conductivity, tunable porosity, and so on. This review summarizes the outstanding materials used for hydrogen evolution reaction and oxygen evolution reaction. And catalysts that acted as both anode and cathode in two-electrode systems for overall water splitting are introduced systematically. The opportunities and challenges of 3D carbon substrate materials for electrochemical water splitting are proposed.展开更多
This study constructed a mathematic model of a variable frequency centrifugal chiller using Simulink software. By running the simulation, it was discovered that when the other factors are constant, the EER(Energy Effi...This study constructed a mathematic model of a variable frequency centrifugal chiller using Simulink software. By running the simulation, it was discovered that when the other factors are constant, the EER(Energy Efficiency Ratio) of the chiller increases with decreases in the temperature of the cooling water and increases in the temperature of the chilled water. The effect of changes in the cooling water temperature on the EER of the chiller is stronger than that of changes in the chilled water temperature. In addition, as the chiller load decreases, the EER increases until reaching a maximum, after which it decreases. Furthermore, the EER of chillers working under a constant flow rate is slightly higher than that of those working under varying flow rates.展开更多
基金supported by the National Natural Science Foundation of China (61525402, 61775095 and 5161101159)Jiangsu Provincial Key Research and Development Plan (BE2017741)
文摘Water splitting is an important approach for energy conversion to obtain hydrogen and oxygen. Apart from solar water splitting, electrochemical method plays a key role in the booming field, and it is urgent to develop novel and efficient catalysts to accelerate water splitting reaction. Recently, newly emerging self-supported materials, especially three dimensional（3D） carbon substrate electrochemical catalysts, have attracted great attention benefiting from their fantastic catalytic performances, such as large surface area,enhanced conductivity, tunable porosity, and so on. This review summarizes the outstanding materials used for hydrogen evolution reaction and oxygen evolution reaction. And catalysts that acted as both anode and cathode in two-electrode systems for overall water splitting are introduced systematically. The opportunities and challenges of 3D carbon substrate materials for electrochemical water splitting are proposed.
基金supported by a Grant-in-Aid for Scientific Research through grant number KM200610016003 from the Beijing Municipal Commission of Education
文摘This study constructed a mathematic model of a variable frequency centrifugal chiller using Simulink software. By running the simulation, it was discovered that when the other factors are constant, the EER(Energy Efficiency Ratio) of the chiller increases with decreases in the temperature of the cooling water and increases in the temperature of the chilled water. The effect of changes in the cooling water temperature on the EER of the chiller is stronger than that of changes in the chilled water temperature. In addition, as the chiller load decreases, the EER increases until reaching a maximum, after which it decreases. Furthermore, the EER of chillers working under a constant flow rate is slightly higher than that of those working under varying flow rates.
