This paper is devoted to solving the transient electric field and transient charge density on the dielectric interface under the electroquasistatic(EQS)field conditions with high accuracy.The proposed method is suitab...This paper is devoted to solving the transient electric field and transient charge density on the dielectric interface under the electroquasistatic(EQS)field conditions with high accuracy.The proposed method is suitable for both 2-D and 3-D applications.Firstly,the governing equations represented by scalar electric potential are discretized by the nodal finite element method(FEM)in space and the finite difference method in time.Secondly,the transient constrained electric field equation on the boundary(TCEFEB)is derived to calculate the normal component of the transient electric field intensities on the Dirichlet boundary and dielectric interface as well as the transient charge density on the dielectric interface.Finally,a 2-D numerical example is employed to demonstrate the validity of the proposed method.Furthermore,the comparisons of the numerical accuracy of the proposed method in this paper with the existing FEMs for electric field intensity and charge density on the dielectric interface are conducted.The results show that the numerical accuracy of the proposed method for calculating the normal component of transient electric field intensities on the Dirichlet boundary and dielectric interface as well as the transient charge density on the dielectric interface is close to that of nodal electric potential and an order of magnitude higher than those of existing FEMs.展开更多
TiAl intermetallic compound was synthesized and bonded together with Ti substrate synchronously by using fieldactivated and pressure-assisted synthesis （FAPAS） process. The effect of electric field on the microstruc...TiAl intermetallic compound was synthesized and bonded together with Ti substrate synchronously by using fieldactivated and pressure-assisted synthesis （FAPAS） process. The effect of electric field on the microstructure and growth pattern of the diffusion dissolution layer of TiA1/Ti interface was mainly studied. The microstructure of the diffusion dissolution layer was investigated by optical microscope （OM） and scanning electron microscope （SEM）. The elements distribution of the diffusion dissolution layer was investigated by energy dispersive spectroscopy （EDS）. The results show that a fine and homogeneous grain structure is obtained in sintered TiA1 intermetallic compound. Metallurgical bond is formed at the TiAl/Ti interface. The thickness of diffusion dissolution layer between TiAl and Ti changes with conduction time and current density.展开更多
Molecular dynamics（MD） simulation was performed to investigate the influence of external electric field on the vapottr-liquid interface of the bubble during the process of toluene separation by air flotation. The ph...Molecular dynamics（MD） simulation was performed to investigate the influence of external electric field on the vapottr-liquid interface of the bubble during the process of toluene separation by air flotation. The physico- chemical properties of vapour-liquid interface, surface tension, probability of a hydrogen bonding near the vapour- liquid interface and the viscosity of liquid phase caused by external electric field were analyzed. The results show that the angle between the water molecule dipole moment and the normal z axis in the vapour phase changes smaller when the external electric field is applied. The surface tension and the probability of hydrogen bonding near the vapour-liquid interface increase with the increase of electric field strength. And the viscosity also increases tinder an external electric field. The results confirm that the external electric field has a positive effect on the performance of bubbles in air flotation, which may provide useful guidance for the combination of electric field and air flotation technology.展开更多
A novel partial silicon-on-insulator laterally double-diffused metal-oxide-semiconductor transistor （PSOI LDMOS） with a thin buried oxide layer is proposed in this paper. The key structure feature of the device is a...A novel partial silicon-on-insulator laterally double-diffused metal-oxide-semiconductor transistor （PSOI LDMOS） with a thin buried oxide layer is proposed in this paper. The key structure feature of the device is an n＋-layer, which is partially buried on the bottom interface of the top silicon layer （PBNL PSOI LDMOS）. The undepleted interface n＋-layer leads to plenty of positive charges accumulated on the interface, which will modulate the distributions of the lateral and vertical electric fields for the device, resulting in a high breakdown voltage （BV）. With the same thickness values of the top silicon layer （10 p.m） and buried oxide layer （0.375 μm）, the BV of the PBNL PSOI LDMOS increases to 432 V from 285 V of the conventional PSOI LDMOS, which is improved by 51.6%.展开更多
Spin splitting of conduction subbands in Al0.3Ga0.7As/GaAs/AlxGa1-xAs/Al0.3Ga0.7As step quantum wells induced by interface and electric field related Rashba effects is investigated theoretically by the method of finit...Spin splitting of conduction subbands in Al0.3Ga0.7As/GaAs/AlxGa1-xAs/Al0.3Ga0.7As step quantum wells induced by interface and electric field related Rashba effects is investigated theoretically by the method of finite difference.The dependence of the spin splitting on the electric field and the well structure,which is controlled by the well width and the step width,is investigated in detail.Without an external electric field,the spin splitting is induced by an interface related Rashba term due to the built-in structure inversion asymmetry.Applying the external electric field to the step QW,the Rashba effect can be enhanced or weakened,depending on the well structure as well as the direction and the magnitude of the electric field.The spin splitting is mainly controlled by the interface related Rashba term under a negative and a stronger positive electric field,and the contribution of the electric field related Rashba term dominates in a small range of a weaker positive electric field.A method to determine the interface parameter is proposed.The results show that the step QWs might be used as spin switches.展开更多
The folding and unfolding of the carbon chain,which is the basic constitutional unit of polymers,are important to the performance of the material.However,it is difficult to regulate conformational transition of the ca...The folding and unfolding of the carbon chain,which is the basic constitutional unit of polymers,are important to the performance of the material.However,it is difficult to regulate conformational transition of the carbon chain,especially in an aqueous environment.In this paper,we propose a strategy to regulate the conformational transition of the carbon chain in water based on the all-atom molecular dynamics simulations.It is shown that the unfolded carbon chain will spontaneously collapse into the folded state,while the folded carbon chain will unfold with an external electric field.The regulation ability of the electric field is attributed to the electric field-induced redistribution of interface water molecules near the carbon chain.The demonstrated method of regulating conformational transition of the carbon chain in water in this study provides an insight into regulating hydrophobic molecules in water,and has great potential in drug molecule design and new polymer material development.展开更多
基金This work was supported by the National Natural Science Foundation of China-State Grid Corporation Joint Fund for Smart Grid(No.U1766219).
文摘This paper is devoted to solving the transient electric field and transient charge density on the dielectric interface under the electroquasistatic(EQS)field conditions with high accuracy.The proposed method is suitable for both 2-D and 3-D applications.Firstly,the governing equations represented by scalar electric potential are discretized by the nodal finite element method(FEM)in space and the finite difference method in time.Secondly,the transient constrained electric field equation on the boundary(TCEFEB)is derived to calculate the normal component of the transient electric field intensities on the Dirichlet boundary and dielectric interface as well as the transient charge density on the dielectric interface.Finally,a 2-D numerical example is employed to demonstrate the validity of the proposed method.Furthermore,the comparisons of the numerical accuracy of the proposed method in this paper with the existing FEMs for electric field intensity and charge density on the dielectric interface are conducted.The results show that the numerical accuracy of the proposed method for calculating the normal component of transient electric field intensities on the Dirichlet boundary and dielectric interface as well as the transient charge density on the dielectric interface is close to that of nodal electric potential and an order of magnitude higher than those of existing FEMs.
文摘TiAl intermetallic compound was synthesized and bonded together with Ti substrate synchronously by using fieldactivated and pressure-assisted synthesis （FAPAS） process. The effect of electric field on the microstructure and growth pattern of the diffusion dissolution layer of TiA1/Ti interface was mainly studied. The microstructure of the diffusion dissolution layer was investigated by optical microscope （OM） and scanning electron microscope （SEM）. The elements distribution of the diffusion dissolution layer was investigated by energy dispersive spectroscopy （EDS）. The results show that a fine and homogeneous grain structure is obtained in sintered TiA1 intermetallic compound. Metallurgical bond is formed at the TiAl/Ti interface. The thickness of diffusion dissolution layer between TiAl and Ti changes with conduction time and current density.
基金Supported by the National Natural Science Foundation of China（No. 51408525）.
文摘Molecular dynamics（MD） simulation was performed to investigate the influence of external electric field on the vapottr-liquid interface of the bubble during the process of toluene separation by air flotation. The physico- chemical properties of vapour-liquid interface, surface tension, probability of a hydrogen bonding near the vapour- liquid interface and the viscosity of liquid phase caused by external electric field were analyzed. The results show that the angle between the water molecule dipole moment and the normal z axis in the vapour phase changes smaller when the external electric field is applied. The surface tension and the probability of hydrogen bonding near the vapour-liquid interface increase with the increase of electric field strength. And the viscosity also increases tinder an external electric field. The results confirm that the external electric field has a positive effect on the performance of bubbles in air flotation, which may provide useful guidance for the combination of electric field and air flotation technology.
基金supported by the Natural Science Foundation of Chongqing Science and Technology Commission(CQ CSTC)(Grant No.cstcjjA40008)the Fundamental Research Funds for the Central Universities,China(Grant No.CDJZR12160003)+1 种基金the China Postdoctoral Science Foundation(Grant Nos.2012M511906 and 2013T60835)Chongqing University Postgraduates’Science and Innovation Fund,China(Grant No.CDJXS12161105)
文摘A novel partial silicon-on-insulator laterally double-diffused metal-oxide-semiconductor transistor （PSOI LDMOS） with a thin buried oxide layer is proposed in this paper. The key structure feature of the device is an n＋-layer, which is partially buried on the bottom interface of the top silicon layer （PBNL PSOI LDMOS）. The undepleted interface n＋-layer leads to plenty of positive charges accumulated on the interface, which will modulate the distributions of the lateral and vertical electric fields for the device, resulting in a high breakdown voltage （BV）. With the same thickness values of the top silicon layer （10 p.m） and buried oxide layer （0.375 μm）, the BV of the PBNL PSOI LDMOS increases to 432 V from 285 V of the conventional PSOI LDMOS, which is improved by 51.6%.
基金supported by the State Key Development Program for Basic Research of China (Nos. 2006CB921607, 2006CB604908)the National Natural Science Foundation of China (No. 60625402)
文摘Spin splitting of conduction subbands in Al0.3Ga0.7As/GaAs/AlxGa1-xAs/Al0.3Ga0.7As step quantum wells induced by interface and electric field related Rashba effects is investigated theoretically by the method of finite difference.The dependence of the spin splitting on the electric field and the well structure,which is controlled by the well width and the step width,is investigated in detail.Without an external electric field,the spin splitting is induced by an interface related Rashba term due to the built-in structure inversion asymmetry.Applying the external electric field to the step QW,the Rashba effect can be enhanced or weakened,depending on the well structure as well as the direction and the magnitude of the electric field.The spin splitting is mainly controlled by the interface related Rashba term under a negative and a stronger positive electric field,and the contribution of the electric field related Rashba term dominates in a small range of a weaker positive electric field.A method to determine the interface parameter is proposed.The results show that the step QWs might be used as spin switches.
基金This work was partially supported by the Zhejiang Provincial Natural Science Foundation of China(No.LR21A020001)the National Natural Science Foundation of China(No.11774313).J.K.was supported by the Start-up fund of Zhejiang Normal University.
文摘The folding and unfolding of the carbon chain,which is the basic constitutional unit of polymers,are important to the performance of the material.However,it is difficult to regulate conformational transition of the carbon chain,especially in an aqueous environment.In this paper,we propose a strategy to regulate the conformational transition of the carbon chain in water based on the all-atom molecular dynamics simulations.It is shown that the unfolded carbon chain will spontaneously collapse into the folded state,while the folded carbon chain will unfold with an external electric field.The regulation ability of the electric field is attributed to the electric field-induced redistribution of interface water molecules near the carbon chain.The demonstrated method of regulating conformational transition of the carbon chain in water in this study provides an insight into regulating hydrophobic molecules in water,and has great potential in drug molecule design and new polymer material development.
