A method to investigate the effect of gas bubble on cell voltage oscillations was established. The whole aluminum electrolysis cell was treated as a resistance circuit, and the dynamic simulation of the cell equivalen...A method to investigate the effect of gas bubble on cell voltage oscillations was established. The whole aluminum electrolysis cell was treated as a resistance circuit, and the dynamic simulation of the cell equivalent circuit was modeled with Matlab/Simulink simulation software. The time-series signals of cell voltage and anode current were obtained under different bubble conditions, and analyzed by spectral and statistical analysis methods. The simulation results show that higher bubble release frequency has a significant effect on the cell voltage oscillations. When the bubble coverage of one anode block exceeds 80%, the cell voltage may exceed its normal fluctuation amplitude. The simulation also proves that the anode effect detected by computer in actual production is mainly the whole cell anode effect.展开更多
The piezoelectric properties of [0001]-oriented ZnO nanowires are investigated via density functional theory （DFT）. The axial effective piezoelectric coefficient of ZnO nanowires is significantly greater than the bu...The piezoelectric properties of [0001]-oriented ZnO nanowires are investigated via density functional theory （DFT）. The axial effective piezoelectric coefficient of ZnO nanowires is significantly greater than the bulk value, and the coefficient increases as the nanowire size decreases. It is proved that the enhancement comes from both the reduction of volume per Zn-O pair and the enhancement of the Poisson＇s ratio. Further study shows that the macroscopic polarization behavior of ZnO nanowires is determined by the crystal structure parameters and the ratio of surface atoms, and an analytic expression is obtained. This work provides a deeper understanding of the size effects of the piezoelectricity of ZnO nanowires and sheds some light on the confusion reported on this subject.展开更多
The electric control of magnetic properties based on magnetoelectric effect is crucial for the development of future data storage devices.Here,based on first-principles calculations,a strong magnetoelectric effect is ...The electric control of magnetic properties based on magnetoelectric effect is crucial for the development of future data storage devices.Here,based on first-principles calculations,a strong magnetoelectric effect is proposed to effectively switch on/off the magnetic states as well as alter the in-plane/perpendicular easy axes of metal-phthalocyanine molecules(MPc)by reversing the electric polarization of the underlying two-dimensional(2D)ferroelectric a-In2Se3 substrate with the application of an external electric field.The mechanism originates from the different hybridization between the molecule and the ferroelectric substrate in which the different electronic states of surface Se layer play a dominant role.Moreover,the magnetic moments and magnetic anisotropy energies(MAE)of OsPc/In2Se3 can be further largely enhanced by a functionalized atom atop the OsPc molecule.The I-OsPc/In2Se3 system possesses large MAE up to 30 meV at both polarization directions,which is sufficient for room-temperature applications.These findings provide a feasible scheme to realize ferroelectric control of magnetic states in 2D limit,which have great potential for applications in nanoscale electronics and spintronics.展开更多
基金Project(2012BAE08B09)supported by the National Key Technology R&D Program of China
文摘A method to investigate the effect of gas bubble on cell voltage oscillations was established. The whole aluminum electrolysis cell was treated as a resistance circuit, and the dynamic simulation of the cell equivalent circuit was modeled with Matlab/Simulink simulation software. The time-series signals of cell voltage and anode current were obtained under different bubble conditions, and analyzed by spectral and statistical analysis methods. The simulation results show that higher bubble release frequency has a significant effect on the cell voltage oscillations. When the bubble coverage of one anode block exceeds 80%, the cell voltage may exceed its normal fluctuation amplitude. The simulation also proves that the anode effect detected by computer in actual production is mainly the whole cell anode effect.
基金This work was supported by the National Major Research Program of China （No. 2013CB932601）, the Major Project of International Cooperation and Exch- anges （No. 2012DFA50990）, the Program of Introducing Talents of Discipline to Universities, the National Natural Science Foundation of China （NSFC） （Nos. 51452001, 51232001, 51372020, and 51372023）, the Fundamental Research Funds for Central Universities, Program for New Century Excellent Talents in Universities, and the Program for Changjiang Scholars and Innovative Research Teams in Universities.
文摘The piezoelectric properties of [0001]-oriented ZnO nanowires are investigated via density functional theory （DFT）. The axial effective piezoelectric coefficient of ZnO nanowires is significantly greater than the bulk value, and the coefficient increases as the nanowire size decreases. It is proved that the enhancement comes from both the reduction of volume per Zn-O pair and the enhancement of the Poisson＇s ratio. Further study shows that the macroscopic polarization behavior of ZnO nanowires is determined by the crystal structure parameters and the ratio of surface atoms, and an analytic expression is obtained. This work provides a deeper understanding of the size effects of the piezoelectricity of ZnO nanowires and sheds some light on the confusion reported on this subject.
基金supported by the National Natural Science Foundation of China(11974307,61574123,11674299,and 11634011)National Key Research and Development Program of China(2017YFA0204904)+3 种基金Fundamental Research Funds for the Central Universities(2019FZA3004,WK2340000082,and WK2060190084)Zhejiang Provincial Natural Science Foundation(D19A040001)Anhui Initiative in Quantum Information Technologies(AHY170000)Strategic Priority Research Program of Chinese Academy of Sciences(XDB30000000)。
文摘The electric control of magnetic properties based on magnetoelectric effect is crucial for the development of future data storage devices.Here,based on first-principles calculations,a strong magnetoelectric effect is proposed to effectively switch on/off the magnetic states as well as alter the in-plane/perpendicular easy axes of metal-phthalocyanine molecules(MPc)by reversing the electric polarization of the underlying two-dimensional(2D)ferroelectric a-In2Se3 substrate with the application of an external electric field.The mechanism originates from the different hybridization between the molecule and the ferroelectric substrate in which the different electronic states of surface Se layer play a dominant role.Moreover,the magnetic moments and magnetic anisotropy energies(MAE)of OsPc/In2Se3 can be further largely enhanced by a functionalized atom atop the OsPc molecule.The I-OsPc/In2Se3 system possesses large MAE up to 30 meV at both polarization directions,which is sufficient for room-temperature applications.These findings provide a feasible scheme to realize ferroelectric control of magnetic states in 2D limit,which have great potential for applications in nanoscale electronics and spintronics.
