阐述交流二自由度混合磁轴承(AC 2 degrees of freedom hybrid magnetic bearings,AC-2DOF-HMB)的结构和工作原理,采用等效磁路法建立了交流磁轴承径向悬浮力数学模型。在此基础上,设计交流磁轴承的控制系统,以TMS320F2812为控制系统的...阐述交流二自由度混合磁轴承(AC 2 degrees of freedom hybrid magnetic bearings,AC-2DOF-HMB)的结构和工作原理,采用等效磁路法建立了交流磁轴承径向悬浮力数学模型。在此基础上,设计交流磁轴承的控制系统,以TMS320F2812为控制系统的CPU研制了硬件,采用参数自整定模糊PID控制规律设计磁轴承控制器,基于C2000环境,用C语言和汇编语言结合开发了相关控制软件程序,并进行实验调试,实现交流混合磁轴承稳定悬浮。研究表明:所设计的交流混合磁轴承数字控制系统不仅能满足磁轴承的性能要求,而且便于参数调试,易于实现各种先进的控制策略。展开更多
The present paper summarizes the results of previous studies, including the structure and principle of the rotary ring flume for researching the fine sediment movement, the mechanism of the flume, method of eliminatin...The present paper summarizes the results of previous studies, including the structure and principle of the rotary ring flume for researching the fine sediment movement, the mechanism of the flume, method of eliminating the influence of the centrifugal force and sediment movement experiments with periodic alternating current. Also included are the experiment-based relationship among sediment concentration, bed shear stress and silt carrying capacity, a proposed erosion-deposition function and bed erosion-deposition calculation together with the results of verification.展开更多
Organic afterglow materials are highly desirable for optoelectronic applications,but they usually suffer from complex preparation process,low quantum efficiency,and short lifetime due to the ultrafast deactivation of ...Organic afterglow materials are highly desirable for optoelectronic applications,but they usually suffer from complex preparation process,low quantum efficiency,and short lifetime due to the ultrafast deactivation of the highly active excited states involved.Here,we succeeded in achieving solventfree thermal syntheses of high-efficiency afterglow CDs@zeolite composite materials by simply grinding the solid raw materials of zeolite and precursor CDs at room temperature,followed by thermal crystallization.This method afforded maximum embedding of CDs into growing zeolite crystals,as well as strong host–guest interaction to surpass the nonradiative transition of CDs,thus producing composite materials with ultralong dual emission of thermally activated delayed fluorescence and room temperature phosphorescence with a record high lifetime of 1.7 and 2.1 s,respectively,and the quantum yield of 90.7%.Furthermore,in a preliminary experiment,we applied the composite materials in alternatingcurrent light-emitting diode supplementary lighting,which exhibited a promising potential in optoelectronic applications.展开更多
A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper. Several factors including the kind, concentration, and volume of acid, the dosa...A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper. Several factors including the kind, concentration, and volume of acid, the dosage of potassium bromide, the temperature and concentration of concomitant substances were investigated in detail. The experimental results indicated that this method was simple, rapid, and sensitive. The linear range was 8.367 × 10(?4) to 2.789 × 10(?2) mol L(?1), the relative standard deviation (R.S.D.) was lower than 0.96%, and the spiked recoveries of aniline in environmental water samples were in the range of 99.4–106.9% under the optimal conditions. The results indicated that the present method could be used as an alternative method for aniline determination in realworld water samples.展开更多
The main objective of this paper is three-fold.First, to provide an overview of the current status of the power electronics technology, one of the key actors in the upcoming smart grid paradigm enabling maximum power ...The main objective of this paper is three-fold.First, to provide an overview of the current status of the power electronics technology, one of the key actors in the upcoming smart grid paradigm enabling maximum power throughputs and near-instantaneous control of voltages and currents in all links of the power system chain. Second, to provide a bridge between the power systems and the power electronic communities, in terms of their differing appreciation of how these devices perform when connected to the power grid. Third, to discuss on the role that the power electronics technology will play in supporting the aims and objectives of future decarbonized power systems. This paper merges the equipment, control techniques and methods used in flexible alternating current transmission systems(FACTS) and high voltage direct transmission(HVDC) equipment to enable a single, coherent approach to address a specific power system problem, using ‘best of breed’ solutions bearing in mind technical, economic and environmental issues.展开更多
文摘阐述交流二自由度混合磁轴承(AC 2 degrees of freedom hybrid magnetic bearings,AC-2DOF-HMB)的结构和工作原理,采用等效磁路法建立了交流磁轴承径向悬浮力数学模型。在此基础上,设计交流磁轴承的控制系统,以TMS320F2812为控制系统的CPU研制了硬件,采用参数自整定模糊PID控制规律设计磁轴承控制器,基于C2000环境,用C语言和汇编语言结合开发了相关控制软件程序,并进行实验调试,实现交流混合磁轴承稳定悬浮。研究表明:所设计的交流混合磁轴承数字控制系统不仅能满足磁轴承的性能要求,而且便于参数调试,易于实现各种先进的控制策略。
文摘The present paper summarizes the results of previous studies, including the structure and principle of the rotary ring flume for researching the fine sediment movement, the mechanism of the flume, method of eliminating the influence of the centrifugal force and sediment movement experiments with periodic alternating current. Also included are the experiment-based relationship among sediment concentration, bed shear stress and silt carrying capacity, a proposed erosion-deposition function and bed erosion-deposition calculation together with the results of verification.
基金Foundation of China(grant nos.21621001,21920102005,21835002,and 21671075)the 111 Project of China(B17020)the financial supports.
文摘Organic afterglow materials are highly desirable for optoelectronic applications,but they usually suffer from complex preparation process,low quantum efficiency,and short lifetime due to the ultrafast deactivation of the highly active excited states involved.Here,we succeeded in achieving solventfree thermal syntheses of high-efficiency afterglow CDs@zeolite composite materials by simply grinding the solid raw materials of zeolite and precursor CDs at room temperature,followed by thermal crystallization.This method afforded maximum embedding of CDs into growing zeolite crystals,as well as strong host–guest interaction to surpass the nonradiative transition of CDs,thus producing composite materials with ultralong dual emission of thermally activated delayed fluorescence and room temperature phosphorescence with a record high lifetime of 1.7 and 2.1 s,respectively,and the quantum yield of 90.7%.Furthermore,in a preliminary experiment,we applied the composite materials in alternatingcurrent light-emitting diode supplementary lighting,which exhibited a promising potential in optoelectronic applications.
文摘A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper. Several factors including the kind, concentration, and volume of acid, the dosage of potassium bromide, the temperature and concentration of concomitant substances were investigated in detail. The experimental results indicated that this method was simple, rapid, and sensitive. The linear range was 8.367 × 10(?4) to 2.789 × 10(?2) mol L(?1), the relative standard deviation (R.S.D.) was lower than 0.96%, and the spiked recoveries of aniline in environmental water samples were in the range of 99.4–106.9% under the optimal conditions. The results indicated that the present method could be used as an alternative method for aniline determination in realworld water samples.
基金supported by Spanish Ministry of Economy and Competitiveness and Junta de Andalucía through the projects ENE2014-54115-R and TEP-7411
文摘The main objective of this paper is three-fold.First, to provide an overview of the current status of the power electronics technology, one of the key actors in the upcoming smart grid paradigm enabling maximum power throughputs and near-instantaneous control of voltages and currents in all links of the power system chain. Second, to provide a bridge between the power systems and the power electronic communities, in terms of their differing appreciation of how these devices perform when connected to the power grid. Third, to discuss on the role that the power electronics technology will play in supporting the aims and objectives of future decarbonized power systems. This paper merges the equipment, control techniques and methods used in flexible alternating current transmission systems(FACTS) and high voltage direct transmission(HVDC) equipment to enable a single, coherent approach to address a specific power system problem, using ‘best of breed’ solutions bearing in mind technical, economic and environmental issues.
