光束通过在静电场作用下的α-碘酸锂单晶产生的垂直于c向的散射带

激光束通过c向静电场作用下的α-碘酸锂单晶时,观察到与c向正交而且张角很大的散射带,其强度在透射光斑的两侧并不对称。当入射光的电向量垂直于c向时,散射光的电向量则平行于c向;而前者平行于c向时,后者则垂直于c向。如果入射光的电向量既不垂直也不平行于c向,则出现电向量分别平行和垂直于c向的两条散射带,在特定条件下它们相重合。本工作详细研究了散射带的偏振态、强度分布的类准周期结构及其弛豫行为等。我们认为这种散射带很可能是由于晶体中载流子沿c向运动产生的某种效应所引起。同时用显微镜观察了解电场作用下α-腆酸锂单 关键词：     

Finite Element Analysis of the Dominant Mode Variation in Groove Guide

In this paper, the dominant mode in groove guide is analyzed by finite element method. For the guide with a shallow groove, the electric field lines (abbreviated as E lines) are perpendicular to the parallel plate, which is different from the literatures, and the dominant mode distribution is irrelevant to the groove width; for the guide with a narrow but deeper groove, the E lines are parallel to the plate region, which represents the characteristics of lower attenuation, for the guide with a deeper and wider groove, a complicated E lines are obtained. These results reveal that the dominant mode distribution in groove guide is varied, which replenish our understanding of groove guide, and the results have important values in design, manufacture, and application of groove guide.     

有耗介质层上多导体传输线的电磁耦合时域分析方法

目前,针对空间电磁场作用有耗介质层上传输线的电磁耦合,仍缺乏有效的数值分析方法.因此,本文提出一种高效的时域混合算法,很好地解决了有耗介质层上传输线电磁耦合建模难的问题.首先,对经典传输线方程进行改进,推导了适用于有耗介质层上多导体传输线电磁耦合分析的修正传输线方程.然后,结合时域有限差分方法和相应插值技术,求解修正传输线方程,获得多导线及其端接负载上的电压和电流响应,并实现空间电磁场辐射与多导线瞬态响应的同步计算.最后,通过相应计算实例的数值模拟,与CST软件的仿真结果进行对比,验证了时域混合算法的正确性和高效性.     

Measurement of large parallel and perpendicular electric fields on electron spatial scales in the terrestrial bow shock

Large parallel (相似文献   

Field-induced light deflection in lithium niobate and lithium tantalate: the possible configurations

Field-induced light deflection by ferroelectric domain walls in lithium niobate (LN) and lithium tantalate (LT) is theoretically studied. The phenomenon can occur not only when both the incident wave vector k and the electric field E are parallel to the z-axis—as demonstrated by experiments made so far—but also when E and/or k are perpendicular to z. In particular, for E parallel to x and k parallel to y, the deflection phenomenon is predicted to have the same characteristics as in triclinic or monoclinic ferroelastics: the large deflection angle is related to the natural birefringence, whereas the deflection amplitude is proportional to the small tilt angle of the neutral lines, which is here induced by the electric field. In periodic domain structures, interference between deflected waves occurs, and the deflected intensity is expected to be largely enhanced when the Bragg condition is satisfied. This transverse configuration is thus specially attractive to characterize periodically-poled crystals.     

Excessive hydrogen and deuterium Balmer lines broadening in a hollow cathode glow discharges

Results of a Doppler spectroscopy study of hydrogen and deuterium Balmer lines in the stainless steel and copper hollow cathode glow discharge, operated in pure hydrogen, deuterium and mixtures of inert gases with hydrogen, are reported. For all gases and gas mixtures plasma observations perpendicular to electric field revealed the excessively large Doppler broadening. By changing mode of glow discharge operation, the Doppler broadened line profiles in helium-hydrogen mixture are recorded parallel to the discharge electric field as well. The excessively broadened part of the H line profile is shifted towards blue or red wavelength by changing the direction of electric field vector. The presence of large excessive Balmer lines broadening in pure hydrogen and in its gas mixture with neon as well as shifting of the excessively broadened part of line profile by means of electric field is in contradiction with the resonance transfer model proposed by Mills et al. in several publications, see e.g. [IEEE Trans. Plasma Sci. 31, 338 (2003)].     

无限长均匀带电直线组电场分布的复势解法

给出无限长均匀带电直线的复势,接着讨论平行直线排列与平行环形排列两种情况下,无限长均匀带电直线组的复势与电场,并由此得出相应的电场线与等势线方程.     

Magnetic field line random walk in non-axisymmetric turbulence

Including a random component of a magnetic field parallel to an ambient field introduces a mean perpendicular motion to the average field line. This effect is normally not discussed because one customarily chooses at the outset to ignore such a field component in discussing random walk and diffusion of field lines. A discussion of the basic effect is given, indicating that any random magnetic field with a non-zero helicity will lead to such a non-zero perpendicular mean motion. Several exact analytic illustrations are given of the effect as well as a simple numerical illustration.     

Polarization direction characters of local electric field around dielectric coated gold nanowire

The local electric field components in the dielectric wall with a long gold nanowire in its core are calculated based on quasi-static theory. The calculated results show that the complete polarized incident light does not only stimulate same directional complete polarized local electric field. The same directional polarized electric field only locates close to the poles of the core wire and is parallel or perpendicular to the polarized direction of the incident radiation. On the other hand, incident light also stimulates perpendicular directional polarization, which densely locates close to the poles of the core wire in the direction with an included angle π/4 or 3π/4 makes with polarization direction of incident light. Furthermore, local electric field components in the wall also depend on the dielectric constant of dielectric wall and surrounding medium. When dielectric constant of the wall is less than that of surrounding, the areas of perpendicular directional polarized local field in the wall reduce and shift greatly. At the same time, more parallel directional polarized local field focus in the poles of the wall along the incident polarization. PACS 78.67.Bf; 73.20.Mf; 36.40.Gk; 78.66.Bz; 73.20.Mf     

Electric field effects on an optically-pumped HCOOH FIR laser and Zeeman laser theory

Electric field effects have been investigated on the output power of six far-infrared (FIR) laser lines from H¹²COOH optically-pumped by a CO₂ laser with its polarization arranged perpendicular to the Stark field. Optoacoustic signals observed on the pump lines were hardly affected by the applied electric field up to 0.6 kV/cm. By neglecting the electric field effects on the pump transitions, Zeeman laser theory has been applied to the FIR laser transitions. Numerical calculation predicts the observed FIR output power as a function of electric field. Experessions for oscillation frequency and intensity in homogeneous limit are given, which may be applicable to any FIR Stark laser so far as the pump transition is free from electric field effects.     

Transmission optique,en lumiere polarisse,de couches tres minces de potassium,sous incidence oblique

The transmission factors of potassium thin films have been determined for incidence angles of 0°, 45°, 70°, the electric field E being either parallel or perpendicular to the incidence plane. These factors present important differences according to the polarization. Evidence has been found for the existence of two anomalous absorption bands. These bands can be connected with the existence of two plasma frequencies, which are associated with an electric field component parallel or perpendicular to the thin film.     

Behaviour of nematic liquid crystals doped with ferroelectric nanoparticles in the presence of an electric field

A planar nematic liquid crystal cell (NLC) doped with spherical ferroelectric nanoparticles is considered. Polarisation of the nanoparticles are assumed to be along the NLC molecules parallel and antiparallel to the director with equal probability. The NLC molecules anchoring to the cell walls are considered to be strong, while soft anchoring at the nanoparticles surface is supposed. Behaviour of the NLC molecules and nanoparticles in the presence of a perpendicular electric field to the NLC cell is theoretically investigated. The electric field of the nanoparticles is taken into account in the calculations. Freedericksz transition (FT) threshold field in the presence of nanoparticles is found. Then, the director and particles reorientations for the electric fields larger than the threshold field are studied. Measuring the onset of the nanoparticles reorientation is proposed as a new method for the FT threshold measurement.     

Polarization of line radiation in the presence of external electric quadrupole and uniform magnetic fields

The polarization of emission lines formed in a medium immersed in external electric and magnetic fields is studied. The electric field is assumed to be quadrupolar in nature, while the magnetic field is uniform. We show that the quadrupole electric field produces line splitting which is characteristically different from the Zeeman effect. While the line components emitted along the quantization axis are circularly polarized in Zeeman effect, they are, in contrast, linearly polarized in the case of a pure quadrupole electric field. The emission perpendicular to the quantization axis produces three linearly polarized components in Zeeman effect, whereas only two linearly polarized components are observed in the case of quadrupole electric fields. Lack of azimuthal symmetry in the quadrupole electric field leads to polarized line components which appear quite differently for different azimuthal angles of the line of sight.     

Anisotropy of the photo-induced persistent internal polarization of a semiconductor

A theory is presented for the anisotropy of the persistent internal polarization, i.e. for its dependence on the angle between the applied electric field and thec-axis as it has been observed with Li-doped ZnO crystals. Starting point is a Boltzmann equation with anisotropic collision and capture terms. From it, a relation is derived between the ratios of the polarizations for electric fields perpendicular and parallel to thec-axis and of the effective capture cross sections for photo electrons moving parallel and perpendicular to thec-axis.     

利用Matlab模拟点电荷系的电场线和等势面

根据电场叠加原理,利用Matlab的绘图功能,绘出二维平面内点电荷系的等势面和电场线。以三个点电荷为例,模拟了它们的电场线和等势面,并通过改变电荷的位置和电荷量的大小对电场的分布情况进行分析比较,在教学中能起到很好的演示作用。     

Radioelectric effect in a superlattice under the action of an elliptically polarized electromagnetic wave

The density of the current associated with the drag of charge carriers in a superlattice by an elliptically polarized electromagnetic wave is calculated. Two cases of the mutual orientation of the Umov-Poynting vector and the superlattice axis, i.e., their parallel and perpendicular orientations, are analyzed. It is shown that, for the parallel orientation, the radioelectric effect can change sign. The influence of the longitudinal dc electric field on the radioelectric effect is investigated under the conditions where a circularly polarized electromagnetic wave propagates along the superlattice axis. The current density is studied as a function of the electric field strength and the electromagnetic wave intensity. It is demonstrated that the direction of the electric current is changed at specific values of the dc field strength and the wave intensity.     

GaAs半导体量子箱中电子的斯塔克效应

在有效质量近似下,利用变分法研究了在GaAs半导体量子箱中电子能量的斯塔克效应.结论表明：电场平行于量子箱的中心轴时,斯塔克能移只与量子箱高度有关;电场垂直于中心轴时,斯塔克能移仅仅与它的截面尺寸有关.当电场方向与中心轴夹角为任意角时,斯塔克能移与高度和截面都有关.同时在低场和高场极限下,理论上分析了电场大小和量箱尺寸对斯塔克能移的影响.     

GaAs半导体量子箱中电子的斯塔克效应

在有效质量近似下,利用变分法研究了在GaAs半导体量子箱中电子能量的斯塔克效应.结论表明:电场平行于量子箱的中心轴时,斯塔克能移只与量子箱高度有关;电场垂直于中心轴时,斯塔克能移仅仅与它的截面尺寸有关.当电场方向与中心轴夹角为任意角时,斯塔克能移与高度和截面都有关.同时在低场和高场极限下,理论上分析了电场大小和量箱尺寸对斯塔克能移的影响.     

Two Problems about Conducting Strips

Problems concerning isolated conducting strips and conducting strips placed in a uniform electric field which is parallel to the plane of the strip or is perpendicular to the boundary of the strip are solved.     

NMR study of triglycine sulphate (TGS) in electric field perpendicular to the ferroelectric axis

The electric field applied perpendicular to the ferroelectric axis bHOP (in Hoshino, Okaya, Pepinsky notation) of the TGS crystal, results new domain structure-striped domains with walls parallel to the cHOP axis. The process is accompanied by changes of the dielectric properties. We present the results of NMR study of TGS crystal with electric field applied parallel to the cHOP or to the cHOP x bHOP directions. After 12 h application of the DC field, a decrease in amplitude of the 1H NMR central line is observed.