特殊的电像法研究多个导体球的相互作用

推广了一般导体和点电荷电像,用迭代电像法计算了两个导体球之间的作用力与电容,并做了推广以及精确性分析.进一步给出了多个导体球的一般计算方式.作为多导体球问题的例子给出了第三个无静电荷的导体球对两导体球体系的影响.给出了导体作用数值计箅的具体方式,并且为导体相互作用实质提供了清晰的物理图像.     

圆柱形导体壳的霍尔效应

提出了一种同轴电缆结构的霍尔效应装置.若中心导体通电流,则在通电的导体壳内外表面之间产生霍尔电势差.讨论了导体壳电势差与中心导体的电流强度、导体壳的电流强度以及导体壳结构之间的关系,发现导体壳很薄时霍尔电势差最大.     

基于高温超导带材的三通道导体载流特性的仿真研究

本文基于三通道扭曲堆叠导体和准各向同性导体, 提出了三通道准各向同性导体. 在有限元仿真软件中使用自洽模型对两种导体进行建模, 分析并对比了两种三通道导体的临界电流、 临界电流各向异性、 工程电流密度与导体半径之间的关系. 仿真结果表明三通道准各向同性导体在背景场条件下具有使用价值, 同时也为提高两种三通道导体工程电流密度提出了建议。     

有限长导体棒的电荷分布的数值模拟

利用有限差分法对有限长导体棒电荷面密度进行了数值模拟.数值模拟结果说明,有限长带电导体棒面电荷分布不仅与导体表面的曲率半径有关,还与导体的总体形状以及导体周围环境中其他导体的分布有关.     

损耗对CICC导体设计影响的模拟研究

聚变装置上低温超导磁体的管内电缆导体(Cable-in-Conduit Conductor,CICC)运行在大电流和快速变化磁场环境中,导体的合理设计是其能否稳定运行的关键。由于工程上CICC导体的设计是一个多次尝试和优化的过程,为此提出了基于稳定性和损耗机理的导体设计思想;推导了关于CICC导体结构参数矩阵方程;建立了导体数值仿真的基本设计模型。同时进行了导体的模拟设计,并将仿真设计结构与工程设计情况进行了比较和分析,结果证明二者吻合的较好。     

用双极坐标求解带电导体圆柱和无限大接地导体平板间的电势

利用双极坐标求解了带电导体圆柱和无限大接地导体平板间的电势分布,并对带电导体圆柱表面的电荷分布及无限大接地导体平板表面的电荷分布作了讨论.     

接近速度对空气静电放电特性的影响

 通过理论分析和实验测量，研究了导体接近速度对空气放电的影响。理论计算了两导体相互接近时导体的自（互）电容系数、导体电势差、导体电势差随导体间的间隙（放电间隙）的变化率和导体电势差的时间变化率。实验研究了5 kV和10 kV放电电压下放电电流峰值和耦合电压峰-峰值随接近速度的变化关系。接近速度直接决定了空气击穿时导体电势差的时间变化率，同时也就决定了不同速度下的空气放电特性；接近速度影响了火花击穿的时间延迟，从而对空气放电产生了时间效应。     

电流连续的细导体段模型的磁场及电感

传统的载流细导体段模型是分析导体闭合回路磁场的基本模型,尽管不满足电流连续性定律,但适用于导体闭合回路的磁场分析.然而,对于工程中只关注导体闭合回路中某一局部的多分支导体段并联的电流分配问题,传统模型将不能完整地反映各分支导体段之间磁场的相互作用.为此,现有文献提出的位移电流模型,满足了电流连续性定律,较好地解决了上述问题,但是,仍然存在理论不完整、不自洽以及计算公式复杂等问题.本文提出载流细导体段的传导电流模型,确保了载流细导体段在段内、段端及段外的电流连续性.推导出物理内涵更加深刻的总磁场微分方程和矢量磁位计算公式.提出载流细导体段传导电流模型磁场能量和电感的计算公式,极大地降低了计算复杂度,弥补了现有文献的不足.本文算例从模型、公式、计算等方面验证了本文理论和计算公式的正确性.     

CICC导体数值模拟设计的发展

管内电缆导体(Cable-in-Conduit Conductor,简称CICC)是大型低温超导磁体的首选导体,在大电流和快速变化磁场环境中,CICC导体能否稳定运行受多种因素影响,因而对CICC导体的稳定性以及导体的设计进行数值模拟,来简化工程上CICC导体设计研究的复杂烦琐过程,缩短工作周期。目前,国内外关于CICC数值模拟的程序,由于侧重于解决不同的问题,各有利弊。基于此,文中在系统阐述CICC数值模拟领域内的相关情况后,对它们进行了全新的总结和论述,并给出了导体数值模拟研究的一些可能发展方向。     

衍射问题一级近似的微扰理论

作者应用微扰理论首先导出了顶角接近π的平面扇形导体衍射场与θ接近π/2的橢锥导体衍射场的微扰项之表达式,因此,对其相应的简单问题——导体半平面屏的衍射与导体平面的反射,也得到了相应的微扰项之表达式。然后,按照文献[10]中所提出的原理,以内接多边形代替一般形状的导体薄片,以许多内接小橢锥面组成的曲面代替一般形状的导体表面,分别将上述微扰对多边形各顶点及曲面各内接锥顶求和。在极限情况下,求和变为积分,从而分别导出了任意形状的导体薄片(因而导体平面屏上的开孔)与导体表面衍射的一级衍射场,它们是对几何光学场的一     

Energy losses of a charged particle in a plasma in the presence of a strong electric field as a function of the sign of the charge

Institute of Radiophysics and Electronics, Academy of Sciences of the Armenian SSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 34, No. 4, pp. 347–351, April, 1991.     

On the dynamics of a particle on a hyperboloid

A free particle moving on a one-sheeted hyperboloid is discussed both at the classical and quantum levels.     

On the dynamics of a particle on a cone

A detailed study of the classical and quantum mechanics of a free particle on a double cone and a particle bound to its tip by a harmonic oscillator potential is presented.     

On the asymmetry of a random walk in the presence of a field

Any ensemble of random walks with symmetric transition probabilities will have symmetric properties. However, any single realization of such a random walk may be asymmetric. In an earlier paper, Weiss and Weissman developed a measure of asymmetry and applied it to random walks in the absence of a field, showing that the degree of asymmetry (in the diffusion limit) is independent of time and that the most probable degree of asymmetry corresponds to the maximum possible. We show in the present paper how the presence of a symmetric field can change this result, both in making the degree of asymmetry depend on time, and driving the random walk toward a more symmetric state.     

Toward the theory of spin waves on the surface of a nanotube with a superlattice in a magnetic field

Electron spin waves on the surface of a semiconductor nanotube with a superlattice in a magnetic field have been considered. The spin-wave spectra and regions of collisionless wave damping have been found. It has been shown that the spin waves do not exhibit damping on small-radius tubes with a degenerate electron gas.     

Anisotropy of the oscillation dynamics of a breather on a trap in the electroconvective twist structure of a nematic

The oscillation dynamics of dislocations with a dissociated nucleus in the electroconvective twist structure of a nematic liquid crystal has been studied. The initial state of the roll twist structure is unstable. One of the origins of this is the helical flows of the nematic in the neighboring rolls with the antiparallel axial velocity components. As a result, oscillating or “breathing” defects are formed, which have the properties of breathers and are described by the sine-Gordon equation. It has been demonstrated that the space-time anisotropy of the character of motion of the dislocations in opposite directions orthogonal to the roll structure takes place in such a nonstationary system.     

Influence of the polarity of a medium on the photonics of a merocyanine dye with a high quadratic polarizability

The influence of the polarity of a medium on the spectral and luminescent properties of 2-[(2E,4E)-6-(1,3,3-trimethyl-2,3-dihydro-1H-2-indolyliden)-2,4-hexadienyliden]malononitrile (THDM) in solutions and polymer matrices is studied at room temperature under conditions of steady-state and pulsed laser excitation. A large bathochromic shift of the absorption spectra observed upon an increase in the polarity of a solvent is caused by a strong increase in the molecular dipole moment μ due to a transition of molecules from the ground state (μ_g = 7.6 D) to an excited Franck-Condon state (μ^FC = 33.5 D). Based on the solvatochromic data, the quadratic polarizability was calculated to be β = (3.2 ± 0.6) × 10^?28 esu, which is close to the experimentally determined value β_ex = (3.9 ± 0.2) × 10^?28 esu. A strong narrowing of the fluorescence spectra in comparison with the absorption spectra is observed upon an increase in the solvent polarity. This narrowing is explained by a decrease in the bond length alternation parameter and by weakening of vibronic interactions in the singlet excited state. The dynamic solvatofluorochromism of THDM in the picosecond range is caused by reorientations of molecules of the polar environment occurring during a time period consistent with the dielectric relaxation time of these molecules.