用电容器的电阻和电容特性公式计算非平行板电容器的电容

讨论了电容器的电阻和电容特性公式,计算了非平行板电容器的电阻和电容.     

用四端星形电阻网络到四端网状电阻网络的等效变换求田字形不对称电阻网络的等效电阻

本文简明推导了四端星形电阻网络到四端网状（全网）电阻网络的等效变换式,并应用它导出了田字形不对称电阻网络的等效电阻．     

基于递推-变换方法计算圆柱面网络的等效电阻及复阻抗

获得任意电阻网络等效电阻的解析解一直是科学和数学上的难题.本文采用递推-变换方法研究了一类任意m×n阶圆柱面网络的等效电阻及复阻抗问题.首先采用网络分析建立递推矩阵方程模型;其次构造对角化矩阵变换方法以便获得矩阵的特征值和特征向量,从而获得矩阵方程的通解;再次采用网络分析建立边界条件约束方程模型,进而获得矩阵方程的特解;最后利用矩阵逆变换给出支路电流的解析解,从而获得任意m×n阶圆柱面网络轴线上等效电阻的解析解,所得结果由特征根构成及单求和表达.作为公式的应用,给出了任意半无限和无限情形时的数个新的等效电阻公式,在与其他文献结论的对比研究中得到了一个有趣的新的三角函数恒等式.研究了圆柱面RLC网络的等效复阻抗问题,给出了精确的等效复阻抗公式.     

On the elimination of DC in reconstructed wavefronts from in-line holograms

New experimental results to demonstrate that the annoying DC in the reconstructed wavefronts from in-line holograms could be successfully eliminated are presented in this paper. The complete elimination of DC has been achieved by making proper use of a Mach-Zehnder interferometer. The results for an in-line hololens and an in-line Fourier transform hologram are discussed. Contribution No. 8 from Laboratories for Coherent Optics and Electrooptical Research.     

狭义相对论教学中的几个问题

本文讨论了相对论教学中几个方面的问题,包括常见例子的问题,洛伦兹变换的方便形式,同时相对性例子在另一参考系的讨论,长度测量在另一参考系看到的现象,时间延缓及运动参考系各点时间不同和光的多普勒效应的简单推导.通过不同过程在不同参考系中的讨论,掌握在运动系讨论问题的方法,以及同一过程在不同惯性系内的不同表现,而所有现象的测量结论在洛伦兹变换下保持不变.     

不同负载下直流偏磁对特高压变压器各侧绕组电流影响的计算及分析

基于特高压变压器的时域场路耦合模型, 利用磁场模型中的能量扰动原理以及电路模型中动态电感参数建立瞬态电路偏微分方程模型。对特高压变压器负载时绕组电流受直流偏磁的影响进行了仿真计算, 针对阻性、感性和容性三种不同负载类型, 对绕组电流进行了直流偏磁计算, 并对其各次谐波变化进行了分析。面对特高压变压器大电感、小电阻带来的极为漫长的过渡过程以及直流偏磁计算易被淹没的难点, 通过在电路模型中增加串联电阻, 使达到稳态的时间大大缩短, 并通过电压迭代补偿, 有效消除增大串联电阻值导致的计算偏差, 通过对比所加偏置电流值与串联绕组中的直流分量值验证了本文模型的正确性。     

A Note on the Transformation of Variables of KP Equation,Cylindrical KP Equation and Spherical KP Equation

In a recent article(Commun. Theor. Phys. 67(2017) 207), three(2+1)-dimensional equations — KP equation, cylindrical KP equation and spherical KP equation, have been reduced to the same Kd V equation by using different transformation of variables, respectively. In this short note, by adding an adjustment item to original transformation, three more general transformation of variables corresponding to above three equations have been given.Substituting the solutions of the Kd V equation into our transformation of variables, more new exact solutions of the three(2+1)-dimensional equations can be obtained.     

膨胀球面运动时的形状问题

算出了膨胀球面运动时的形状,从而说明光的波前为什么不因为长度收缩而成为椭球面.     

Aberration and the question of equivalence of some ether theories to special relativity

In the last two decades, theories explaining the same experiments as well as special relativity does, were developed by using different synchronization procedures. All of them are ether-like theories. Most authors believe these theories to be equivalent to special relativity, but no general proof was ever given. By means of agedanken experiment on light aberration, we produce strong evidence that this is the case for experiments made in inertial systems.     

A Spectroscopic Investigation of Spatial Symmetry of Radiation in the U-shaped DC Argon Plasma with Aerosol Supply

Radial distributions of plasma parameters, temperature, and electron number density, together with radial distribution of analyte absorption and emission, were investigated in order to obtain insight into the radial symmetry of low-current (≤ 10 A), atmospheric pressure, argon stabilized arc with tangential introduction of the aerosol. For plasma diagnostics, several methods were used: measurements of H_β line profile, absolute intensity measurements of the argon 430.01-nm line, and of the spectrally adjacent continuum and power interruption technique. It was found that the inevitable asymmetry in aerosol introduction has negligible influence on basic plasma parameters but influences considerably the spatial distribution of the analyte particle spectral absorption and emission.     

Growth of resistance with density of scatterers in one dimensional wave propagation

We study wave propagation in a one-dimensional disordered array of scattering potentials. We consider three different ensembles of scatterer configurations: anN-ensemble with a fixed numberN of scatterers, anL-ensemble with a varying number of scatterers distributed over a fixed lengthL, and anNL-ensemble where bothN andL are fixed. The latter ensemble allows a detailed study of the mean resistance and its variance for a fixed lengthL as the number of scatterersN increases. We find that the Landauer result, which predicts an exponential increase of the mean resistance withN, is valid only in the low-density regime. At high density the mean resistance grows exponentially with N and the concept of optical potential applies. In the crossover regime we find an interesting resonance.     

Small variations in the sheet resistance of graphene layers with compressive and tensile bending

We synthesized graphene on copper foil by chemical vapor deposition using H₂ and CH₄ gases, followed by transferring the synthesized graphene onto various substrates. Controlling the number of layers was achieved through the variation of transfer times, and the variations of sheet resistance and transmittance with the number of layers were measured. We also investigated the variation of resistance with the radius of curvature of graphene film. As the radius decreased, the resistance increased with tensile bending and decreased with compressive bending. However, the degree of changing resistance is small enough to be applicable into flexible devices. The resistance of monolayer graphene was found to be varied in the range of as small as ±3% by the tensile or compressive bending. It was further found that although the degree of changing resistance gets larger with increasing number of graphene, the tensile bending increased the resistance by less than 20% even in case of four layer graphene.