同轴电缆自感系数计算的讨论

本文认为用电动势法计算同轴电缆的自感系数物理意义更加明确．     

静电场和稳恒电流磁场的两种物理图象：对电动力学教材的一点补充

本文介绍静电场和稳恒电流磁场的两种等价的物理图象．对这些图象有清晰的认识可以使学生在解决具体问题时思路清楚，避免一些错误．     

模拟静电场实验中导电介质的选择

通过比较3种静电场描绘仪器的实验结果,分析误差产生的原因,指出选择导电介质应注意的问题。     

均匀线性介质中电容器漏电电阻与电容的关系

利用漏电电阻、电容的场量表达式 ,推导出充以均匀线性介质电容器的漏电电阻与电容之间的关系为 RC=ε/σ.当已知漏电电阻 (或电容 )时 ,利用该关系可以方便地求出电容 (或漏电电阻 )     

浅谈“电流场模拟静电场”实验中的二场的比拟

本讨论了“用稳恒电流场模拟静电场”实验中的二场比拟的依据和条件。     

求解稳恒磁场的谐函数展开法

推导出稳恒磁场矢势的谐函数展开式,当稳恒电流的分布适宜于用直角坐标系表示时,可应用该展开式求解磁场,给出了应用该展开式求解稳恒磁场的例子。     

同轴电缆自感系数的计算

1 引题 一同轴电缆由中心导体圆柱和外层导体薄圆筒组成，二者的半径分别为R1和R2，若电流由中心圆柱流出由圆筒流回，可看成一回路，如图1所示．试计算单位长度该电缆的自感系数．     

静电场和稳恒电流磁场诸定律的统一性浅探

从点电荷的场强公式出发，根据狭义相对论中场强张量的变换，推导出了静电场和稳恒电流磁场的诸定律，使学生对电场和磁场的统一性有了更为深刻的认识．     

静电场和稳恒电流磁场诸定律的统一浅探

从点电荷的场强公式出发，根据狭义相对论中场强张量的交换，推导出了静电场和稳恒电流磁场的诸定律，使学生对电场和磁场的统一性有了更为深刻的认识。     

静电场模拟实验的教学研究

用稳恒电流场模拟静电场是理工科大学生的必修物理实验.在传统的物理实验教学中,一般使用等臂记录法获取实验数据,然后根据等势电压与等势圆半径的对数的线性关系,进而求出内圆柱电极半径和外环电极内半径.本文根据实验数据的特点,分别使用指数拟合法、二元线性回归法和A类不确定度法同时处理用稳恒电流场模拟静电场中得出的实验数据,给出稳恒电流场模拟静电场实验的误差分析.通过对比,对数据处理方法在实验教学中的应用进行了相关分析和研究.     

10 kV紧凑型三相同轴高温超导电缆交流损耗研究

根据10 kV紧凑型三相同轴高温超导电缆参数,在COMSOL Multiphysics有限元软件中建立电缆的二维仿真模型,基于H方程求解了电缆在额定工况稳态运行时以及不同传输电流下的磁场分布和交流损耗;在此基础上,分析了绕制半径、相间距离以及相间相对角度对交流损耗的影响.仿真结果表明,各相超导层绕制半径越小,相间距离越小,各相产生的交流损耗越小;三相的交流损耗有随着超导层结构周期性变化的特点,且当相间相对角度为0°时,各相产生的交流损耗最大.     

大型超导电缆交流损耗的计算

给出了超导电缆交流损耗的表达式。使用这些表达式 ,并基于 HT- 7U极向场线圈系统在等离子体建立时的电流波形 ,计算了 AC损耗在 PF导体上的能量沉积。最后讨论了电缆参数对AC损耗的影响     

The Design of Passive Optical Networking+Ethernet over Coaxial Cable Access Networking and Video-on-Demand Services Carrying

Abstract

Video on demand is a very attractive service used for entertainment, education, and other purposes. The design of passive optical networking+Ethernet over coaxial cable accessing and a home gateway system is proposed. The network integrates the passive optical networking and Ethernet over coaxial cable to provide high dedicated bandwidth for the metropolitan video-on-demand services. Using digital video broadcasting, IP television protocol, unicasting, and broadcasting mechanisms maximizes the system throughput. The home gateway finishes radio frequency signal receiving and provides three kinds of interfaces for high-definition video, voice, and data, which achieves triple-play and wire/wireless access synchronously.     

Resistance Calculation of Pentagonal Lattice Structure of Resistors

In this study, the effective resistance between any two lattice sites in a two-dimensional pentagonal lattice structure of identical resistors is determined by means of the lattice Green’s function method. Some numerical results of the resistance for small separations between lattice sites are presented.     

Calculation of Magnetic Configuration and Resistance for Nanomagnets

Based on a classical Heisenberg lattice model with dipole interaction and the method of spin dynamic simulation,the magnetic configurations (MC),hysteresis loop (HL) and magnetic resistance (MR) of the nanomagnets with different geometries,such as circle,square and rectangle,are studied for different directions of applied field.In the case of perpendicular field to the plane,the magnetization and MR are reversible and have not hysteresis.When the field is applied in the plane,the HL is irreversible and is qualitatively well agreeable with the current experimental results.The MR loop is also irreversible and appears two peaks distributed at two sides around zero field.The peaks of magnetic resistance are relative to the vortex state of similar configuration.Large easy-axis anisotropy will suppress the MC anisotropy,and the large magnetoresistance effect disappears.     

Coaxial Mirau interferometer

We describe a new interferometric configuration for optical coherence tomography that is based on the Mirau interferometer. It uses the photodetector included in a superluminescent diode package, which makes possible a highly miniaturized device. Other advantages of the configuration include its totally coaxial structure, confocal microscope operation, availability of the full working distance of the imaging objective, and no central obscuration. Fundamental characteristics such as resolution and dynamic range are discussed, and the result of measurement on a rough metallic surface is presented.     

Coaxial waveguide gyro-peniotron

A coaxial waveguide gyro-peniotron with largeorbit beam is proposed. The linear thoery of 3-D model is given to describe this device. The influences of the beam radius and beam current on the normalized growth rate are discussed in terms of numerical analysis.     

Coaxial Relativistic Backward Wave Oscillator and Coaxial Master Oscillator-Power Amplifier

A two and one half dimensional particle-in-cell code MAGIC has been used to investigate the nonlinear beam-wave interaction in a coaxial relativistic backward wave oscillator(RBWO) and optimize the dependence of the output power on electron beam nature parameter, slow wave structure geometry and magnetic guide field. The optimum conditions for the coaxial RBWO were obtained. The simulation results show: the coaxial RBWO can generate 3.2GW peak output power at 10.2GHz in the TM₀₂ made when an annular electron beam of 20KA is accelerated across a diode potential of 600KV and guided through a section of uniform coaxial corrugated waveguide by an axial magnetic field of 25KG, the peak efficiency is about 27% . A novel coaxial master oscillator–power amplifier was presented in this paper.     

Resistance Calculation for an Infinite Simple Cubic Lattice Application of Green's Function

It is shown that the resistance between the origin and any lattice point (l,m,n) in an infinite perfect Simple Cubic (SC) lattice is expressible rationally in terms of the known value of G ₀ (0,0,0). The resistance between arbitrary sites in an infinite SC lattice is also studied and calculated when one of the resistors is removed from the perfect lattice. The asymptotic behavior of the resistance for both the infinite perfect and perturbed SC lattice is also investigated. Finally, experimental results are obtained for a finite SC network consisting of 8×8×8 identical resistors, and a comparison with those obtained theoretically is presented.