在传统电芬顿技术的基础上引入感应铁电极以改变Fe^(2+)的投加方式,构建了以铁板为感应阳极、不锈钢板为阳极、高纯度TiO_2镀膜石墨板为阴极的感应电芬顿体系。为探究感应电芬顿处理染料废水的最优运行参数及参数间的交互作用,采用响应...在传统电芬顿技术的基础上引入感应铁电极以改变Fe^(2+)的投加方式,构建了以铁板为感应阳极、不锈钢板为阳极、高纯度TiO_2镀膜石墨板为阴极的感应电芬顿体系。为探究感应电芬顿处理染料废水的最优运行参数及参数间的交互作用,采用响应曲面法建立连续变量曲面模型,优化试验并确定最佳水平范围。结果显示,经模型优化后的最佳工艺条件为:反应时间80 min,pH 2.59,电流密度30 m A·cm^(-2),在此条件下进行三组平行实验,得出染料废水的COD去除率平均值达到70.1%,而模型预测值为73.17%,实测值与预测值相对偏差为3.07%,两者能较好地吻合。展开更多
The flux-weakening performance of a permanent magnet brushless AC drive was investigated using both floating-point and fixed-point DSP controllers. A significant current oscillation was observed when the drive was ope...The flux-weakening performance of a permanent magnet brushless AC drive was investigated using both floating-point and fixed-point DSP controllers. A significant current oscillation was observed when the drive was operated at high-speed in the flux-weakening mode with the fixed-point DSP. The investigation showed that this was due to the on-line compensation of the winding resistance voltage drop and quantisation errors associated with the fixed-point architecture of the DSP. A simple look-up table scheme is proposed to eliminate the oscillation and to achieve extended flux-weakening capability.展开更多
Quorum sensing is one kind of cell-to-cell signalling system among microorganisms that works in response to their population density via autoinducers exemplified by AHL and oligopeptides. In this study, fourteen AHL d...Quorum sensing is one kind of cell-to-cell signalling system among microorganisms that works in response to their population density via autoinducers exemplified by AHL and oligopeptides. In this study, fourteen AHL derivatives were synthesised by a chemical synthesis method, and two types of AHL derivatives were measured and screened by crystal violet staining assay, which have more obvious inhibitory effects on A. ferrooxidans biofilms under arsenic environment. Their structures were verified through IR and NMR identification. The morphological changes of A. ferrooxidans under the influence of the AHL derivatives were compared. In addition, the effects of AHL derivatives(0.1 μg/mL and 1 μg/mL) on membrane formation of A. ferrooxidans under high concentration of arsenic resistance(1,600 mg/L) were explored. Solid experimental data firstly showed that a portion of logarithmic microorganisms were ruptured under the effect of high arsenic concentration. Secondly, the volume of the cell shrank and the number of extracellular polymeric substances decreased after the addition of the AHL derivatives at high concentrations. Therefore, we found here that two derivatives used at concentrations of 0.1 μg/mL and 1 μg/m L accompanied with high concentration of arsenic can both effectively restrict biofilms formation by A. ferrooxidans.展开更多
To select the proper composition and obtain an overall material?microstructure?property relationship for Cu?Fe alloy, theeffect of Fe content on microstructure and properties of Cu?Fe-based composite coatings by laser...To select the proper composition and obtain an overall material?microstructure?property relationship for Cu?Fe alloy, theeffect of Fe content on microstructure and properties of Cu?Fe-based composite coatings by laser induction hybrid rapid claddingwas investigated. Microstructure characterization of the composite coatings was tested utilizing SEM, XRD and EDS. Microhardnessmeasurement was executed to evaluate the mechanical properties of the composite coatings. The results show that for low Fe content,the composite coating presents a feature that Fe-rich equiaxed dendrites are embedded in the Cu-rich matrix. With increasing Fecontent, the Fe-rich particles are dispersed in the Cu-rich matrix. With further increasing Fe content, large amounts of Cu-richparticles are homogeneously dispersed in the interdendrite of the Fe-rich matrix. Correspondingly, the average microhardness of thecomposite coatings increases gradually with the increase of Fe content and the microhardness of Cu14.5Fe83Si2C0.5 coating is muchtwice higher than that of the substrate.展开更多
Although plating is a necessary process for SMT components, it alters the magnetic characteristics and inductance level of Ni-Cu-Zn ferrite components. The results of this work show that the following three factors in...Although plating is a necessary process for SMT components, it alters the magnetic characteristics and inductance level of Ni-Cu-Zn ferrite components. The results of this work show that the following three factors in plating affect these components, and the effects are different for Ni- and Sn-plating： （1） Plating layers exert stresses and react with the residual stress of components to change the inductance level, and the effect of the tin layer is greater than that of the nickel one; （2） The plating current induces a magnetic field inside the components directly and indirectly, and this remains as remanence inside the components and reduces the inductance level, and the effect level of Ni-plating is greater than that of Sn-plating; （3） The plating solution corrodes the interface of the termination and ferrite core of the components to release the residual stress, and causes an increase in inductance, and the effect of Sn-plating is greater than that of Ni-plating. In addition, the inductance level is the result of the net effect of these three factors, and if the sintering temperature is increased to change in the type of residual stress, the net effect will be changed.展开更多
We study the ferrimagnetic properties of spin 1/2 and spin-1 systems by means of the effective field theory. The system is considered in the framework of bond dilution mixed Blume-Capel mode/ （BCM） with random singl...We study the ferrimagnetic properties of spin 1/2 and spin-1 systems by means of the effective field theory. The system is considered in the framework of bond dilution mixed Blume-Capel mode/ （BCM） with random single-ion anisotropy. The investigation of phase diagrams and magnetization curves indicates the existence of induced magnetic ordering and single or multi-compensation points. Special emphasis is placed on the influence of bond dilution and random single-ion anisotropy on normal or induced magnetic ordering states and single or multi-compensation points. Normal magnetic ordering states take on new phase diagrams with increasing randomness （bond and anisotropy）, while anisotropy induced magnetic ordering states are always occurrence no matter whether concentration of anisotropy is large or small. Existence and disappearance of compensation points rely strongly on bond dilution and random singleion anisotropy. Some results have not been revealed in previous papers and predicted by Néel theory of ferrimagnetism.展开更多
Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. Different compositions of ferrite, Zn_((1-x))Cu_xFe_2O_4(x=0.0, 0.25, 0.50, 0.75), characterized by XRD, reveal single phase inverse spine...Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. Different compositions of ferrite, Zn_((1-x))Cu_xFe_2O_4(x=0.0, 0.25, 0.50, 0.75), characterized by XRD, reveal single phase inverse spinel in all the samples. With increasing copper content, the crystallite size increases. The surface morphology of all the samples, studied by SEM, shows porous structure of particles. The prepared samples were also analyzed by FT-IR and TEM. Catalytic activity of the samples was studied on lanthanum oxalate decomposition by thermogravimety.The rate constant k has the highest value with x=0.75 and 5%(mole fraction) of the catalyst and is attributed to high copper content, the mixed sites Cu^(2+)-Fe^+ and/or Cu^+-Fe^(2+) ion pairs besides the one component sites Cu^(2+)-Cu^+, Fe^(3+)-Fe^(2+), as a result of mutual charge interaction. In other words, the increasing activity of mixed oxides is attributed to increase in the content of active sites via creation of new ion pairs. With increasing Zn content, particle size increases. Variation of catalytic activity of ferrite powders is due to the changes of the valence state of catalytically active components of the ferrites, which oxidizes the carbon monoxide released from lanthanum oxalate.展开更多
In general, it is important to operate the; airgap length uniformly for improving the system efficiency independent of the flatness of the reaction plate in a railway propulsion system by a linear induction motor （LI...In general, it is important to operate the; airgap length uniformly for improving the system efficiency independent of the flatness of the reaction plate in a railway propulsion system by a linear induction motor （LIM）. And it is possible to operate the LIM propulsion system efficiently without a change of the LIM capacity through the airgap length control on the sloped rail. So, in this research, the authors introduce an airgap control system to control the airgap length which depends on the flatness of the secondary reaction plate when the LIM is operated, and design a rotary small-scaled LIM and its airgap control system before manufacturing the real system. Then, the authors analyze some characteristics of the LIM （thrust and normal force, input current, efficiency and power factor）, and through the LIM control modeling, the authors finally analyze an effect of the airgap-length control of the LIM by the airgap control system.展开更多
The cell circuit design and test of inductive adder pulse generator for kicker magnet are presented in the paper.The 3.3kV IGBT,a large dimension nanocrystalline core and a 2.5kV 50uF energy storage capacitor are used...The cell circuit design and test of inductive adder pulse generator for kicker magnet are presented in the paper.The 3.3kV IGBT,a large dimension nanocrystalline core and a 2.5kV 50uF energy storage capacitor are used. The multi-channel trigger IGBT driver board is designed.IGBT failures under short circuit condition and protection scheme are explored.The multi-cell prototype is designed.The waveforms of experiments are presented.It turns out that the rise and fall time of the output pulse is fast and the pulse width is adjustable.The maximum current of pulse reaches 2kA.It satisfies the higher requirement of beam injection technology.展开更多
文摘在传统电芬顿技术的基础上引入感应铁电极以改变Fe^(2+)的投加方式,构建了以铁板为感应阳极、不锈钢板为阳极、高纯度TiO_2镀膜石墨板为阴极的感应电芬顿体系。为探究感应电芬顿处理染料废水的最优运行参数及参数间的交互作用,采用响应曲面法建立连续变量曲面模型,优化试验并确定最佳水平范围。结果显示,经模型优化后的最佳工艺条件为:反应时间80 min,pH 2.59,电流密度30 m A·cm^(-2),在此条件下进行三组平行实验,得出染料废水的COD去除率平均值达到70.1%,而模型预测值为73.17%,实测值与预测值相对偏差为3.07%,两者能较好地吻合。
文摘The flux-weakening performance of a permanent magnet brushless AC drive was investigated using both floating-point and fixed-point DSP controllers. A significant current oscillation was observed when the drive was operated at high-speed in the flux-weakening mode with the fixed-point DSP. The investigation showed that this was due to the on-line compensation of the winding resistance voltage drop and quantisation errors associated with the fixed-point architecture of the DSP. A simple look-up table scheme is proposed to eliminate the oscillation and to achieve extended flux-weakening capability.
基金Project(31660026)supported by the National Natural Science Foundation of ChinaProject(lzujbky-2016-152)supported by the National Basic Research Program of China
文摘Quorum sensing is one kind of cell-to-cell signalling system among microorganisms that works in response to their population density via autoinducers exemplified by AHL and oligopeptides. In this study, fourteen AHL derivatives were synthesised by a chemical synthesis method, and two types of AHL derivatives were measured and screened by crystal violet staining assay, which have more obvious inhibitory effects on A. ferrooxidans biofilms under arsenic environment. Their structures were verified through IR and NMR identification. The morphological changes of A. ferrooxidans under the influence of the AHL derivatives were compared. In addition, the effects of AHL derivatives(0.1 μg/mL and 1 μg/mL) on membrane formation of A. ferrooxidans under high concentration of arsenic resistance(1,600 mg/L) were explored. Solid experimental data firstly showed that a portion of logarithmic microorganisms were ruptured under the effect of high arsenic concentration. Secondly, the volume of the cell shrank and the number of extracellular polymeric substances decreased after the addition of the AHL derivatives at high concentrations. Therefore, we found here that two derivatives used at concentrations of 0.1 μg/mL and 1 μg/m L accompanied with high concentration of arsenic can both effectively restrict biofilms formation by A. ferrooxidans.
基金Projects(51471084,61475117)supported by the National Natural Science Foundation of ChinaProject(13ZCZDGX01109)supported by Tianjin Municipal Science and Technology Commission of ChinaProject(20122BBE500031)supported by the Key Technology Project of Jiangxi Province in China
文摘To select the proper composition and obtain an overall material?microstructure?property relationship for Cu?Fe alloy, theeffect of Fe content on microstructure and properties of Cu?Fe-based composite coatings by laser induction hybrid rapid claddingwas investigated. Microstructure characterization of the composite coatings was tested utilizing SEM, XRD and EDS. Microhardnessmeasurement was executed to evaluate the mechanical properties of the composite coatings. The results show that for low Fe content,the composite coating presents a feature that Fe-rich equiaxed dendrites are embedded in the Cu-rich matrix. With increasing Fecontent, the Fe-rich particles are dispersed in the Cu-rich matrix. With further increasing Fe content, large amounts of Cu-richparticles are homogeneously dispersed in the interdendrite of the Fe-rich matrix. Correspondingly, the average microhardness of thecomposite coatings increases gradually with the increase of Fe content and the microhardness of Cu14.5Fe83Si2C0.5 coating is muchtwice higher than that of the substrate.
文摘Although plating is a necessary process for SMT components, it alters the magnetic characteristics and inductance level of Ni-Cu-Zn ferrite components. The results of this work show that the following three factors in plating affect these components, and the effects are different for Ni- and Sn-plating： （1） Plating layers exert stresses and react with the residual stress of components to change the inductance level, and the effect of the tin layer is greater than that of the nickel one; （2） The plating current induces a magnetic field inside the components directly and indirectly, and this remains as remanence inside the components and reduces the inductance level, and the effect level of Ni-plating is greater than that of Sn-plating; （3） The plating solution corrodes the interface of the termination and ferrite core of the components to release the residual stress, and causes an increase in inductance, and the effect of Sn-plating is greater than that of Ni-plating. In addition, the inductance level is the result of the net effect of these three factors, and if the sintering temperature is increased to change in the type of residual stress, the net effect will be changed.
文摘We study the ferrimagnetic properties of spin 1/2 and spin-1 systems by means of the effective field theory. The system is considered in the framework of bond dilution mixed Blume-Capel mode/ （BCM） with random single-ion anisotropy. The investigation of phase diagrams and magnetization curves indicates the existence of induced magnetic ordering and single or multi-compensation points. Special emphasis is placed on the influence of bond dilution and random single-ion anisotropy on normal or induced magnetic ordering states and single or multi-compensation points. Normal magnetic ordering states take on new phase diagrams with increasing randomness （bond and anisotropy）, while anisotropy induced magnetic ordering states are always occurrence no matter whether concentration of anisotropy is large or small. Existence and disappearance of compensation points rely strongly on bond dilution and random singleion anisotropy. Some results have not been revealed in previous papers and predicted by Néel theory of ferrimagnetism.
文摘Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. Different compositions of ferrite, Zn_((1-x))Cu_xFe_2O_4(x=0.0, 0.25, 0.50, 0.75), characterized by XRD, reveal single phase inverse spinel in all the samples. With increasing copper content, the crystallite size increases. The surface morphology of all the samples, studied by SEM, shows porous structure of particles. The prepared samples were also analyzed by FT-IR and TEM. Catalytic activity of the samples was studied on lanthanum oxalate decomposition by thermogravimety.The rate constant k has the highest value with x=0.75 and 5%(mole fraction) of the catalyst and is attributed to high copper content, the mixed sites Cu^(2+)-Fe^+ and/or Cu^+-Fe^(2+) ion pairs besides the one component sites Cu^(2+)-Cu^+, Fe^(3+)-Fe^(2+), as a result of mutual charge interaction. In other words, the increasing activity of mixed oxides is attributed to increase in the content of active sites via creation of new ion pairs. With increasing Zn content, particle size increases. Variation of catalytic activity of ferrite powders is due to the changes of the valence state of catalytically active components of the ferrites, which oxidizes the carbon monoxide released from lanthanum oxalate.
文摘In general, it is important to operate the; airgap length uniformly for improving the system efficiency independent of the flatness of the reaction plate in a railway propulsion system by a linear induction motor （LIM）. And it is possible to operate the LIM propulsion system efficiently without a change of the LIM capacity through the airgap length control on the sloped rail. So, in this research, the authors introduce an airgap control system to control the airgap length which depends on the flatness of the secondary reaction plate when the LIM is operated, and design a rotary small-scaled LIM and its airgap control system before manufacturing the real system. Then, the authors analyze some characteristics of the LIM （thrust and normal force, input current, efficiency and power factor）, and through the LIM control modeling, the authors finally analyze an effect of the airgap-length control of the LIM by the airgap control system.
文摘The cell circuit design and test of inductive adder pulse generator for kicker magnet are presented in the paper.The 3.3kV IGBT,a large dimension nanocrystalline core and a 2.5kV 50uF energy storage capacitor are used. The multi-channel trigger IGBT driver board is designed.IGBT failures under short circuit condition and protection scheme are explored.The multi-cell prototype is designed.The waveforms of experiments are presented.It turns out that the rise and fall time of the output pulse is fast and the pulse width is adjustable.The maximum current of pulse reaches 2kA.It satisfies the higher requirement of beam injection technology.
