Nanosized nickel oxide powders were prepared by thermal decomposition of the nickel citrate gel precursors. The thermal decomposition and powder materials derived from calcination of these gel precursors with various ...Nanosized nickel oxide powders were prepared by thermal decomposition of the nickel citrate gel precursors. The thermal decomposition and powder materials derived from calcination of these gel precursors with various ratios of citric acid （CA） to nickel at different temperatures and times were characterized by thermal analysis （TG/DTA）, scanning electron microscopy （SEM）, x-ray diffraction （XRD）, and measurement of specific surface area （BET） with porosity analyses. The optimized processing conditions of calcination temperature 400℃ for 1 hour with the CA/Ni ratio of 1.2, were determined to produce the nanosized nickel oxide pow- ders with a high specific surface area of 181 m^2/g, nanometer particle sizes of 15-25 nm, micro-pore diameter distribution between 4-10 nm. The capacitance characteristics of the nanosized nickel oxide electrode in various concentrations of KOH solutions were studied by the cyclic voltammetry （CV） exhibiting both a double-layer capacitance and a faradaic pseudocapacitance. The nanosized nickel oxide electrode shows a high cyclic stability and is promising for high performance electrochemical capacitors.展开更多
The purpose of this article was to analyze data associated with advances in wind energy across the United States. While governments, academia, and the private sector generally know patterns of wind turbine development...The purpose of this article was to analyze data associated with advances in wind energy across the United States. While governments, academia, and the private sector generally know patterns of wind turbine development (</span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> turbine size and capacity growing in recent years), there is no known independent, reliable, and/or updated summary of these variables. Using data collected by the Lawrence Berkeley National Laboratory and partners, this study used descriptive statistics to show turbine development and growth patterns from </span><span style="font-family:Verdana;">1981-2019. The newly created United States Wind Turbine Database (USWTDB</span><span style="font-family:Verdana;">) represents the most comprehensive account of wind turbine information and was updated in January 2020. Variables I am interested in here are turbine manufacturer, state of project, turbine and project capacity, and turbine size. Findings provide empirical evidence to support the common, yet previously unrefined statements that wind turbines are growing larger in number, size and capacity. This growth is varied over spatial and temporal scales. I also provide evidence to show patterns of turbine manufacturing, with GE Wind dominating much of the US wind energy landscape today. I hope this work provides a timely resource for those interested in a variety of questions surrounding wind energy development in the United States. Perhaps more importantly, this analysis will hopefully inspire others to use what the USWTDB provides and answer larger questions surrounding wind energy futures.展开更多
A kind of dielectric barrier discharge（DBD） device composed of water electrodes with 3×3forms can produce large-area low-temperature plasmas at atmospheric pressure.To reflect the discharge characteristics of D...A kind of dielectric barrier discharge（DBD） device composed of water electrodes with 3×3forms can produce large-area low-temperature plasmas at atmospheric pressure.To reflect the discharge characteristics of DBD better,a dynamic simulation model,which is based on the voltage controlled current source（CCS）,is established,then the established model in Matlab/Simulink is used to simulate the DBD in air.The voltage-current waves and Lissajous at a voltage of 10 kV,11 kV and 12 kV peak value with a frequency of 15 kHz are studied.The change of the discharge power of DBD with a different amplitude and frequency of applied voltage is also analyzed.The result shows the voltage-current waves,Lissajous and discharge power of DBD under different conditions from the simulation agree well with those of the experiment.In addition,we propose a method to calculate the dielectric barrier capacitance Cd and the gap capacitance Cg,which is valid through analyzing the variation of capacitance at different voltage amplitudes.展开更多
基金the National Natural Science Foundation of China(No.50134020)
文摘Nanosized nickel oxide powders were prepared by thermal decomposition of the nickel citrate gel precursors. The thermal decomposition and powder materials derived from calcination of these gel precursors with various ratios of citric acid （CA） to nickel at different temperatures and times were characterized by thermal analysis （TG/DTA）, scanning electron microscopy （SEM）, x-ray diffraction （XRD）, and measurement of specific surface area （BET） with porosity analyses. The optimized processing conditions of calcination temperature 400℃ for 1 hour with the CA/Ni ratio of 1.2, were determined to produce the nanosized nickel oxide pow- ders with a high specific surface area of 181 m^2/g, nanometer particle sizes of 15-25 nm, micro-pore diameter distribution between 4-10 nm. The capacitance characteristics of the nanosized nickel oxide electrode in various concentrations of KOH solutions were studied by the cyclic voltammetry （CV） exhibiting both a double-layer capacitance and a faradaic pseudocapacitance. The nanosized nickel oxide electrode shows a high cyclic stability and is promising for high performance electrochemical capacitors.
文摘The purpose of this article was to analyze data associated with advances in wind energy across the United States. While governments, academia, and the private sector generally know patterns of wind turbine development (</span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> turbine size and capacity growing in recent years), there is no known independent, reliable, and/or updated summary of these variables. Using data collected by the Lawrence Berkeley National Laboratory and partners, this study used descriptive statistics to show turbine development and growth patterns from </span><span style="font-family:Verdana;">1981-2019. The newly created United States Wind Turbine Database (USWTDB</span><span style="font-family:Verdana;">) represents the most comprehensive account of wind turbine information and was updated in January 2020. Variables I am interested in here are turbine manufacturer, state of project, turbine and project capacity, and turbine size. Findings provide empirical evidence to support the common, yet previously unrefined statements that wind turbines are growing larger in number, size and capacity. This growth is varied over spatial and temporal scales. I also provide evidence to show patterns of turbine manufacturing, with GE Wind dominating much of the US wind energy landscape today. I hope this work provides a timely resource for those interested in a variety of questions surrounding wind energy development in the United States. Perhaps more importantly, this analysis will hopefully inspire others to use what the USWTDB provides and answer larger questions surrounding wind energy futures.
基金supported by the National Natural Science Foundation of China(NSFC) under Contract No.10775055the special funds of State Key Laboratory of Advanced Elcctromag-netic Engineering and Technology,Huazhong University of Science and Technology(Grant No. 2014ZZ001)
文摘A kind of dielectric barrier discharge（DBD） device composed of water electrodes with 3×3forms can produce large-area low-temperature plasmas at atmospheric pressure.To reflect the discharge characteristics of DBD better,a dynamic simulation model,which is based on the voltage controlled current source（CCS）,is established,then the established model in Matlab/Simulink is used to simulate the DBD in air.The voltage-current waves and Lissajous at a voltage of 10 kV,11 kV and 12 kV peak value with a frequency of 15 kHz are studied.The change of the discharge power of DBD with a different amplitude and frequency of applied voltage is also analyzed.The result shows the voltage-current waves,Lissajous and discharge power of DBD under different conditions from the simulation agree well with those of the experiment.In addition,we propose a method to calculate the dielectric barrier capacitance Cd and the gap capacitance Cg,which is valid through analyzing the variation of capacitance at different voltage amplitudes.
