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6篇 您的检索式:作者名="Changhe Du"
    题名 作者 年代 出处 被引量
1Trends of Urban Air Pollution in Zhengzhou City in 1996-2008显示文摘Urban air pollution is a commonly concerned environmental problem in the world.Identification of air quality trend using long-term monitoring data is helpful to understand the effectiveness of pollution control strategies.This study,using data from six monitoring stations in Zhengzhou City,analyzed the changing trend in concentrations of SO 2,NO x /NO 2 and TSP/PM 10 in 1996-2008,based on non-parametric Mann-Kendall test and Sen's slope estimator,and evaluated the comprehensive air pollution level using Multi-Pollutant Index(MPI).It was found that the concentration of each pollutant exceeded obviously the World Health Organization(WHO) guideline value,but the changing trend varied:SO 2 and NO 2 were significantly increased mainly due to an increase in coal consumption and vehicle number,while NO x,TSP and PM 10 decreased.The air pollution was serious,and differed markedly among the three functional regions:it is the most severe in the Industrial and Residential Area(IRA),followed by the Transportation Hub and Business District(THBD),and then the High-tech,Cultural and Educational Area(HCEA).Different from NO 2 concentration that had a similar change trend/rate among the function regions,the change rate of PM 10 concentration differed spatially,decreased much more obviously in THBD than other two regions.For the whole city,the comprehensive air pollution level declined gradually,illustrating that the air quality in Zhengzhou was improved in the last decade.DU Xile LU Changhe WANG Hairong MA Jianhua 2012Chinese Geographical Science2012,22,4:6
2Evaluation and Trend Analysis of Surface Water Quality in Zhengzhou in 1998-2008显示文摘Water pollution is one of the major environmental problems,especially in urban areas.Due to rapid urban expansion and industrialization,water pollution in Zhengzhou City,the capital of Henan Province in central China has become a serious problem for its development.In this study,the surface water quality was evaluated using Nemerow Comprehensive Pollution Index (NCPI),and the change trend was calculated using methods of Mann-Kendall test and Sen's slope estimator,based on the monitoring data from 1998 to 2008.The results show that the NCPI ranged from 3 to 50 in 70% of the monitoring cases,implying that most rivers were seriously polluted.However,this serious polltuon is expected to be gradually improved,as the concentration of water pollutants and NCPI declined significantly in most rivers.Water pollution in reservoirs was much lower than rivers,and the NCPI in the three monitored reservoirs was lower than 3 in most years,and shows a downward trend.Although the surface water quality was gradually improved,great efforts are still needed to enhance the protection and improvement of surface water environment.Du Xile Lu Changhe 2012Chinese Journal of Population,Resources and Environment2012,10,4:1
3Effect of jet nozzle geometry on flow and heat transfer performance of vortex cooling for gas turbine blade leading edge 显示文摘DU Changhe LI Liang WU Xin 2016Applied Thermal Engineering2016,93,:1
4Charge storage coating based triboelectric nanogenerator and its applications in self-powered anticorrosion and antifouling显示文摘As a novel energy-harvesting device,a triboelectric nanogenerator(TENG)can harvest almost all mechanical energy and transform it into electrical energy,but its output is low.Although the micro-nano structures of triboelectrode surfaces can improve their output efficiency,they lead to high costs and are not suitable for large-scale applications.To address this problem,we developed a novel TENG coating with charge-storage properties.In this study,we modified an acrylic resin,a friction material,with nano-BaTiO_(3) particles and gas phase fluorination.The charge-trapping ability of nanoparticles was used to improve the output of TENG.The short-circuit current and the output voltage of coating-based TENGs featuring charge storage and electrification reached 15μA and 800 V,respectively,without decay for longtime working.On this basis,self-powered anticorrosion and antifouling systems are designed to reduce the open circuit potential of A3 steel by 510 mV and reduce the adhesion rate of algae on the surface of metal materials.This study presents a high-output,stable,coating-based TENG with potential in practical applications for anticorrosion and antifouling.Zhitao Zhang Yupeng Liu Min Feng Nannan Wang Changhe Du Shu Peng Yufei Guo Yongjian Liu Ying Liu Daoai Wang 2023Frontiers of Materials Science2023,17,1:0
5CFD-DEM investigation into flow characteristics in mixed pulsed fluidized bed under electrostatic effects显示文摘Static electricity has an important effect on gas–solid fluidized bed reactor fluidization performance.In the process of fluidization,electrostatic interaction between particles will obviously accelerate particle agglomerate formation,which consequently reduces the fluidization performance.Pulsed gas flow injection is an efficient method to enhance particle mixing,thereby weakening the occurrence of particle agglomerate.In this study,the two-dimensional hybrid pulsed fluidized bed is established.The flow characteristics are studied by using the coupled CFD-DEM numerical simulation model considering electrostatic effects.Influences of different pulsed frequencies and gas flow ratios on fluidized bed fluidization performance are investigated to obtain the optimal pulsed gas flow condition.Results show that in the presence of static electricity,the bubble generation position is lower,which is conducive to the particle flow.Pulsed gas flow can increase the particle velocity and improve the diffusion ability.The bubble generation time is different at different frequencies,and the frequency of 2.5 Hz has the most obvious effect on the flow characteristics.Different gas flow ratios have significant impacts on the particle movement amplitude.When the pulse gas flow accounts for a large ratio,the particle agglomerate tends to be larger.Therefore,in order to improve the fluidization effect,the ratio of pulsed gas flow to stable gas flow should be appropriately reduced to 0.5 or less.Hongwei Li Lei Wang Changhe Du Wenpeng Hong 2022Particuology2022,20,7:0
6Achieving macroscale superlubricity with ultra-short running-in period by using polyethylene glycol-tannic acid complex green lubricant显示文摘Superlubricating materials can greatly reduce the energy consumed and economic losses by unnecessary friction.However,a long pre-running-in period is indispensable for achieving superlubricity;this leads to severe wear on the surface of friction pairs and has become one of the important factors in the wear of superlubricating materials.In this study,a polyethylene glycol-tannic acid complex green liquid lubricant(PEG10000-TA)was designed to achieve macroscale superlubricity with an ultrashort running-in period of 9 s under a contact pressure of up to 410 MPa,and the wear rate was only 1.19×10^(–8)mm^(3)·N^(−1)·m^(−1).This is the shortest running-in time required to achieve superlubricity in Si_(3)N_(4)/glass(SiO_(2)).The results show that the strong hydrogen bonds between PEG and TA molecules can significantly reduce the time required for the tribochemical reaction,allowing the lubricating material to reach the state of superlubrication rapidly.Furthermore,the strong hydrogen bond can share a large load while fixing free water molecules in the contact zone to reduce shear interaction.These findings will help advance the use of liquid superlubricity technology in industrial and biomedical.Changhe DU Tongtong YU Zishuai WU Liqiang ZHANG Ruilin SHEN Xiaojuan LI Min FENG Yange FENG Daoai WANG 2023Friction2023,11,5:0
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