ZnS：Mn薄膜电致发光器件中的局域电场

研究了在薄膜电致发光器件中，ＺｎＳ：Ｍｎ光学吸收边附近能带受电场的影响，通过对带边附近电致吸收的研究推导出薄膜电致发光器件发光层内存在局域电场。     

The Effect of Gravity on the Stability of an Evaporating Liquid Film

Evaporation of a Dichloromethane liquid film is explored with an evolution equation describing film dynamics. The film is subject to different initial conditions, smooth and uniform random perturbation. Two different gravity environments (Earth and zero gravity) and two different domain shapes (square and rectangular) have been used. The occurrence of long wave instabilities affecting film dynamics is noted in each of these cases. The evaporating Dicholormethane liquid film is destabilized via long wave instabilities in zero gravity. The thermocapillary patterns formed due to long wave destabilization show a coupling to the initial conditions and domain shape. A criterion for the occurrence of long wave instabilities based on the growth rate of perturbations is described. This equation considers a non-stationary film thickness. It predicts that long wave instabilities are always present in zero gravity environments with a growth rate that increases as the film thickness decreases due to evaporation. Our equation for growth rate of long wave instabilities may be used as an engineering design tool to confine operating parameters of zero gravity heat transfer equipment, that include or harness phase change, to safe limits.     

Effect of Surface Excess Energy Transport on the Rupture of an Evaporating Film

In most of existing works on the instabilities of an evaporating film, the energy boundary condition only takes into account contributions of the evaporation latent heat and the heat conduction in the liquid. We use a new generalized energy boundary condition at the evaporating liquid-vapor interface, in which the contribution of the transport of the Gibbs excess energy is included. We have derived the long-wave equations in which the thickness of film and the interfacial temperature are coupled to describe the dynamics of an evaporating thin film. The results of our computation show that the transport of the Gibbs excess internal energy delay the rupture of thin films due to van de Waals force, evaporating effect and vapor recoil.     

Effects of Electric Field Gradient on an Anti-Plane Crack in Piezoelectric Ceramics

An anti-plane, semi-infinite crack in polarized ceramics is analyzed using the theory of elastic dielectrics with electric field gradient. The effects of electric field gradient on electromechanical fields around the crack is examined.     

Field Effects in Thin Films of Manganites Using a Planar Field Effect Configuration

Modulation of the metal-insulator phase transition of perovskite manganite oxides is achieved by a static electric field. The field is applied using a planar field-effect configuration, which was formed on a monolayer film. In such a field-effect configuration, La_1−x A _x MnO₃ film is used as the channel and substrate acts as the gate. Both divalence-doped (La_0.7Ba_0.3MnO₃, Pr_0.7Sr_0.3MnO₃), and tetravalence-doped (La_0.7Ce_0.3MnO₃) systems demonstrate significant field effects. The field modulations are found being nonlinear and polarity dependent on the applied bias. The results obtained in La_0.7Ce_0.3MnO₃ indicates that electron doped manganites have similar features as those found in hole doped manganites. The observed field effects were discussed with the percolative phase separation picture.     

Optical Mode Characterization of the Configuration of a Thin Ferroelectric Liquid Crystal Cell Under an Applied Electric Field

Abstract

It is possible to probe directly the optic dielectric tensor configuration within a thin (about 3·5 μm) smectic layer of a ferroelectric liquid crystal (FLC) by the propagation of prism-coupled leaky Fabry-Perot optic modes. Incident monochromatic polarized light couples into the resonant modes of the system which are then observed as sharp dips in the reflected signal at specific incident angles. This work has shown that the FLC has an optic tensor profile which is consistent with the chevron formation of the smectic layers observed in X-ray scattering measurements. Also it is shown that under the application of a low d.c. applied field the optic dielectric tensor configuration distorts in a manner consistent with the retention of the chevron structure up to fields of about 10⁶ Vm^?1.     

氧化锌薄膜场效应晶体管的制备及工艺研究

场效应晶体管是现代微电子技术的重要组成部分.为制备氧化锌薄膜晶体管,分析了氧化锌的p型、n型掺杂特性,对p型掺杂进行了实验分析和理论探讨,比较了各种制备氧化锌薄膜晶体管的工艺特点,展示了ZnO在未来电子和光电子领域的潜在应用.     

Effects of an Electric Field and Current on Phase Transformations in Metals and Ceramics

Theoretical and experimental results on the effects of an electric field or current on solid state phase transformations in metals and ceramics are reviewed. Examples are given of the effects on both equilibria and kinetics, and the mechanisms are considered. The available results provide a foundation, but indicate the need for more work. They do, however, indicate that electric fields and currents provide additional parameters for controlling microstructure, and offer the potential for reducing processing costs and related environmental pollution.     

Thin Helium Film on a Glass Substrate

We investigate by Monte Carlo simulations the structure, energetics and superfluid properties of thin ⁴He films (up to four layers) on a glass substrate, at low temperature. The first adsorbed layer is found to be solid and “inert”, i.e., atoms are localized and do not participate to quantum exchanges. Additional layers are liquid, with no clear layer separation above the second one. It is found that a single ³He impurity resides on the outmost layer, not significantly further away from the substrate than ⁴He atoms on the same layer.     

Spin Dynamics of a Fermi Liquid in an Electric Field

The influence of an external electric field on the spin dynamics of an electrically neutral Fermi liquid is considered, the mechanism of such an influence being the relativistic spin-orbital interaction. As a result, Leggett's equations for the spin dynamics of weakly polarized Fermi liquids are generalized to the case of non-zero external electric field. In addition, we obtained the transverse spin dynamics equation for strongly spin-polarized liquids in an electric field at zero temperature. In both situations covariant derivatives depending on the electric field are shown to be substituted for spatial gradients in line with the SU(2) gauge invariance of the microscopic Hamiltonian. The new equations are applied to the study of spin flow along a channel, where an electric field is found to bring about an additional phase shift of the order of magnitude of the phase shift in superfluid ³He-B but growing with time.     

薄膜场发射阴极中纳米线密度的理论优化

现在人们正在研究各种纳米线薄膜 ,因为它们很有可能成为新一代的场发射阴极而被应用于平面显示器等器件中。研究表明 ,除了纳米线的物理特性 ,薄膜的场发射特性也强烈地依赖于纳米线阵列的几何构造。一方面 ,薄膜阴极的纳米线阵列密度要足够大 ,使得大量的场发射源能够产生。另一方面 ,过大的密度带来的屏蔽效应将严重削弱纳米线尖端的局域电场。在本文的参数下 ,利用Ansys软件计算出了纳米线的最佳间距———使得纳米线之间的屏蔽效应可以忽略的最小距离———为纳米线高度的两倍     

电场对Au/SiO_2及Au-Ag/SiO_2表面结构与原子迁移特性的影响

利用扫描俄歇微探针（SAM）和原子力显微镜（AFM）研究了SiO2衬底上在外加直流电场作用下沉积的Au薄膜及Au－Ag复层薄膜的表面形貌、结构变化及电迁移扩散行为。结果表明：①在衬底表面施加水平方向电场辅助沉积制备的Au薄膜其表面显示出平整的椭球形晶粒，并沿外电场方向呈织构取向。与未加电场的热蒸发沉积膜相比，具有较为均匀、有序的表面微观结构。②SiO2表面Au-Ag复层薄膜在直流电场作用下，Au，Ag物种同时向负极方向作走向迁移扩散，这与Au－Ag复层薄膜在Si（111）表面电迁移时Au，Ag分别向两极扩散的特点不同，反映了衬底性质对表面原子电迁移的影响。③Au－Ag复膜在电迁移过程中还发生了表面原子聚集状态的变化，原来沉积排布的细小晶粒在电迁移扩散过程中出现不均匀长大，导致薄膜表面粗糙度显著增加。     

Two-Fraction Electron System on a Thin Helium Film

A systematic theoretical investigation of microwave absorption of 2-dimensional electron systems above a thin helium film in the presence of a cyclotron resonance magnetic field is presented. To explain the measured data, a two-fraction structure of the electron system is introduced. One component corresponds to the free electron motion, the second one takes into account electron localization near the potential minimum caused by the roughness of the substrate. Within this model the general dependence of microwave absorption becomes understandable. The details of the observed cyclotron resonance line-shift are discussed.     

电场作用下铅基阳极表面氧化膜残余内应力产生机理研究

采用SEM、XRD和Raman光谱法研究电场作用下含铬溶液中铅基阳极氧化膜的残余内应力行为、内应力形成, 讨论了氧化膜内应力产生过程与氧化膜表面形貌、物质结构转变的关系。结果表明, 在氧化膜形成初期, Cr₂O₇^2- 和HCrO₄^-离子首先吸附在铅基阳极表面, 电场作用下, 其与铅基体反应并分别形成PbCrO₄和PbO, 同时产生较大内应力。电流密度的增加, 显著提高氧化膜的内应力。随着氧化时间的延长, 阳极析氧行为的加剧, 促进PbO或β-PbO₂形成。同时, 晶粒长大与内应力的不匹配, 导致内应力局部释放, 表现出氧化膜残余内应力减小。铅基氧化膜中不同氧化物组织结构的晶格参数差异, 增加了氧化膜内应力梯度变化, 致使氧化膜破裂。     

The Effects of Temperature and Electric Field on a Quantum Rod Qubit

The Hamiltonian of a quantum rod (QR) with an ellipsoidal boundary is given after a coordinate transformation, which changes the ellipsoidal boundary into a spherical one. We then study the eigenenergies and the eigenfunctions of the ground and the first excited states of an electron strongly coupled to LO-phonon under an applied electric field by using variational method of Pekar type. This QR system may be used as a two-level quantum qubit. When the electron is in the superposition state of the ground and the first excited states, we obtained the time evolution of the electron probability density oscillating in the QR with a certain period. We then investigate the effects of the temperature and the electric field on the time evolution of the electron probability density and the oscillation period. It is found that the electron probability density and the oscillation period increase (decrease) with increasing temperature in lower (higher) temperature regime. The electron probability density decreases (increases) with increasing electric field when the temperature is lower (higher). The oscillation period decreases with the increase of the electric field along the ρ _x direction.     

Size Effects on Levitation Force Between a Magnet and a Superconducting Thin Film in the Meissner State

The levitation force between a permanent magnetic disk and a thin superconducting disk in the Meissner state is calculated using the dipole–dipole interactions model. The levitation force as a function of the magnet and superconductor radii, the levitation height, and the superconductor thickness is studied under the assumption that the radius of the magnet is much smaller than the radius of the superconductor. Results showed an increase in the levitation force as a function of the radius of the superconducting disk. However, the levitation force decreases as the radius of the permanent magnetic disk increases. Demagnetizing effects are taken into account by considering the appropriate demagnetizing factor for the suggested system.     

Toner Jumping Phenomenon in an Electric Field

This article gives a short review on fundamentals of electrophotographic printing using dry toners with conductive or insulative characteristics. The toner jumping phenomenon, TonerJet® technology, toner cloud confinement, and toner cloud beam technology in electric fields are emphasized. Theory and comparison of advantages among toner developments and transport are briefly discussed. The purpose of this article is to advance the development of a novel printing technology, “toner cloud beam,” which has the possibility of using a highly simplified toner imaging mechanism. To clarify the characteristics of conductive toner, the difference between insulative and conductive toner were compared. Unique characteristics of conductive toner are focused on: the up-and-down motion between voltage applied electrodes and cloud formation by confinement at the dented part of the electrode. The present state of the novel printing mechanism is summarized.     

Electric Field Effects on the Thermodynamics of Multiferroic Chains

The thermodynamic properties of the helical spins with a magnetoelectric coupling are studied theoretically using Monte Carlo simulations. It is shown that the spin?Cspin correlations are affected by thermal fluctuations and by an electric field. Results for the temperature-dependence of the ferroelectric polarization and for the electric susceptibility are presented and analyzed with a focus on the multiferroic phase transition.