We consider the inhomogeneous incompressible Navier-Stokes equation on thin domains T^(2)×∈T,∈→0.It is shown that the weak solutions on T^(2)×∈T converge to the strong/weak solutions of the 2D inhomogene...We consider the inhomogeneous incompressible Navier-Stokes equation on thin domains T^(2)×∈T,∈→0.It is shown that the weak solutions on T^(2)×∈T converge to the strong/weak solutions of the 2D inhomogeneous incompressible Navier-Stokes equations on T^(2)as∈→0 on arbitrary time interval.展开更多
The existence of local attractors in thin 2D domains far the weakly damped forced KdV equation, whose principal operator is a non-self adjoint and non-sectorial one is given.
The switching process of ferroelectric thin films in electronic devices is one of the most important requirements for their application. Especially for the different external fields acting on the film surface, the mec...The switching process of ferroelectric thin films in electronic devices is one of the most important requirements for their application. Especially for the different external fields acting on the film surface, the mechanism of domain switching is more complicated. Here we observe the nanoscale domain switchings of Bi3.15Eu0.85Ti3O12 thin film under different mechanical forces at a fast scan rate. As the force increases from initial state to 247.5 n N, the original bright or grey contrasts within the selected grains are all changed into dark contrasts corresponding to the polarization vectors reversed from the up state to the down state, except for the clusters. As the mechanical force increases to 495 n N, the color contrasts in all of the selected grains further turn into grey contrasts and some are even changed into grey contrasts completely showing the typical 90° domain switching. When another stronger loading force 742.5 n N is applied, the phase image becomes unclear and it indicates that the piezoelectric signal can be suppressed under a sufficiently high force, which is coincident with previous experimental results. Furthermore, we adopt the domain switching criterion from the perspective of equilibrium state free energy of ferroelectric nanodomain to explain the mechanisms of force-generated domain switchings.展开更多
The nanocrystalline ferroelectric LiNbO3 films on（001） Si substrates with the random orientation of polycrystalline grains and the predominance of the grains with lateral orientation of the polar axis were grown usi...The nanocrystalline ferroelectric LiNbO3 films on（001） Si substrates with the random orientation of polycrystalline grains and the predominance of the grains with lateral orientation of the polar axis were grown using the ion beam sputtering method. The remanent polarization and the coercive field are 12 μC/cm2and 29 kV/cm, respectively. The thermal annealing leads to the coarsening of the grains. The appearance of the ＂local texture,＂ which gives rise to the unipolarity of the heterostructures caused by the predominance of the one direction in the vertical component of the spontaneous polarization, is investigated.展开更多
Microstructure and magnetic domain structure of thin iron film prepared by sputtering were studied by magnetic force microscopy (MFM). Owing to the high lateral resolution of MFM magnetic structure of a single domain ...Microstructure and magnetic domain structure of thin iron film prepared by sputtering were studied by magnetic force microscopy (MFM). Owing to the high lateral resolution of MFM magnetic structure of a single domain is able to be studied. Two series of iron thin films were grown on microcrystalline glass substrate by DC magnetron sputtering. They were prepared at different Ar pressure and annealing time. The results by magnetic force microscopy show both surface topography of the films and their local magnetic domain structure. It is suggested that the pin effect by single domain wall influence magnetic properties of the iron thin films.展开更多
The microstructure change in thin NiFe/Cu/NiFe films during the magnetization process was observed by the Lorentz electronmicroscopy. TWo types of films were prepared: (1) one NiFe layer with anisotropy and the other ...The microstructure change in thin NiFe/Cu/NiFe films during the magnetization process was observed by the Lorentz electronmicroscopy. TWo types of films were prepared: (1) one NiFe layer with anisotropy and the other layer without, and (2) both NiFe layershave anisotropy normal each other. The domain wall migration and magnetization rotation processes in each of NiFe layers could be observed separately. The presence of magnetic anisotropy in the magnetic layer effectively controls the behavior of magnetic domains. Theinteraction between the two NiFe layers of the film could be observed not so strong in the present experiment.展开更多
FePt thin films and [FePt/Ag]n multilayer thin films were prepared by magnetron sputtering technique and subsequent annealing process. By comparing the microstructure and magnetic properties of these two kinds of thin...FePt thin films and [FePt/Ag]n multilayer thin films were prepared by magnetron sputtering technique and subsequent annealing process. By comparing the microstructure and magnetic properties of these two kinds of thin films, effects of Ag addition on the structure and properties of FePt thin films were investigated. Proper Ag addition was found helpful for FePt phase transition at lower annealing temperature. With Ag addition, the magnetic domain pattern of FePt thin film changed from maze-like pattern to more discrete island-like domain pattern in [FePt/Ag]n multilayer thin films. In addition, introducing nonmagnetic Ag hindered FePt grains from growing larger. The in-depth defects in FePt films and [FePt/Ag]n multilayer films verify that Ag addition is attributed to a large number of pinning site defects in [FePt/Ag]n film and therefore has effects on its magnetic properties and microstructure.展开更多
A new thin film pulse transformer for using in ISND and ADSL systems has been designed based on a domain wall pinning model, the parameters of nano-magnetic thin film such as permeability and coercivity can be calcula...A new thin film pulse transformer for using in ISND and ADSL systems has been designed based on a domain wall pinning model, the parameters of nano-magnetic thin film such as permeability and coercivity can be calculated. The main properties of the thin film transformer including the size, parallel inductance, Q value and turn ratio have been simulated and optimized. Simulation results show that the thin film transformer can be fairly operated in a frequency range of 0.001~20 MHz.展开更多
基金The research is supported by NSFC underGrant Nos.11571167,11771395,11771206 and PAPD of Jiangsu Higher Education Institutions.
文摘We consider the inhomogeneous incompressible Navier-Stokes equation on thin domains T^(2)×∈T,∈→0.It is shown that the weak solutions on T^(2)×∈T converge to the strong/weak solutions of the 2D inhomogeneous incompressible Navier-Stokes equations on T^(2)as∈→0 on arbitrary time interval.
文摘The existence of local attractors in thin 2D domains far the weakly damped forced KdV equation, whose principal operator is a non-self adjoint and non-sectorial one is given.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51272158 and 11302185)the Scientific Research Fund of Hunan Provincial Education Department,China(Grant No.13C901)the Hunan Provincial Natural Science Foundation,China(Grant Nos.14JJ3081 and 13JJ1019)
文摘The switching process of ferroelectric thin films in electronic devices is one of the most important requirements for their application. Especially for the different external fields acting on the film surface, the mechanism of domain switching is more complicated. Here we observe the nanoscale domain switchings of Bi3.15Eu0.85Ti3O12 thin film under different mechanical forces at a fast scan rate. As the force increases from initial state to 247.5 n N, the original bright or grey contrasts within the selected grains are all changed into dark contrasts corresponding to the polarization vectors reversed from the up state to the down state, except for the clusters. As the mechanical force increases to 495 n N, the color contrasts in all of the selected grains further turn into grey contrasts and some are even changed into grey contrasts completely showing the typical 90° domain switching. When another stronger loading force 742.5 n N is applied, the phase image becomes unclear and it indicates that the piezoelectric signal can be suppressed under a sufficiently high force, which is coincident with previous experimental results. Furthermore, we adopt the domain switching criterion from the perspective of equilibrium state free energy of ferroelectric nanodomain to explain the mechanisms of force-generated domain switchings.
文摘The nanocrystalline ferroelectric LiNbO3 films on（001） Si substrates with the random orientation of polycrystalline grains and the predominance of the grains with lateral orientation of the polar axis were grown using the ion beam sputtering method. The remanent polarization and the coercive field are 12 μC/cm2and 29 kV/cm, respectively. The thermal annealing leads to the coarsening of the grains. The appearance of the ＂local texture,＂ which gives rise to the unipolarity of the heterostructures caused by the predominance of the one direction in the vertical component of the spontaneous polarization, is investigated.
文摘Microstructure and magnetic domain structure of thin iron film prepared by sputtering were studied by magnetic force microscopy (MFM). Owing to the high lateral resolution of MFM magnetic structure of a single domain is able to be studied. Two series of iron thin films were grown on microcrystalline glass substrate by DC magnetron sputtering. They were prepared at different Ar pressure and annealing time. The results by magnetic force microscopy show both surface topography of the films and their local magnetic domain structure. It is suggested that the pin effect by single domain wall influence magnetic properties of the iron thin films.
文摘The microstructure change in thin NiFe/Cu/NiFe films during the magnetization process was observed by the Lorentz electronmicroscopy. TWo types of films were prepared: (1) one NiFe layer with anisotropy and the other layer without, and (2) both NiFe layershave anisotropy normal each other. The domain wall migration and magnetization rotation processes in each of NiFe layers could be observed separately. The presence of magnetic anisotropy in the magnetic layer effectively controls the behavior of magnetic domains. Theinteraction between the two NiFe layers of the film could be observed not so strong in the present experiment.
基金the National Natural Science Foundation of China (No. 60571010)the Open Foundation of the Key Laboratory of Ferroelectric and Piezoelectric Materials and Devices of Hubei Province in Hubei University
文摘FePt thin films and [FePt/Ag]n multilayer thin films were prepared by magnetron sputtering technique and subsequent annealing process. By comparing the microstructure and magnetic properties of these two kinds of thin films, effects of Ag addition on the structure and properties of FePt thin films were investigated. Proper Ag addition was found helpful for FePt phase transition at lower annealing temperature. With Ag addition, the magnetic domain pattern of FePt thin film changed from maze-like pattern to more discrete island-like domain pattern in [FePt/Ag]n multilayer thin films. In addition, introducing nonmagnetic Ag hindered FePt grains from growing larger. The in-depth defects in FePt films and [FePt/Ag]n multilayer films verify that Ag addition is attributed to a large number of pinning site defects in [FePt/Ag]n film and therefore has effects on its magnetic properties and microstructure.
文摘A new thin film pulse transformer for using in ISND and ADSL systems has been designed based on a domain wall pinning model, the parameters of nano-magnetic thin film such as permeability and coercivity can be calculated. The main properties of the thin film transformer including the size, parallel inductance, Q value and turn ratio have been simulated and optimized. Simulation results show that the thin film transformer can be fairly operated in a frequency range of 0.001~20 MHz.
