城区百吨硐室大爆破

市区一直被视作大爆破的禁区。文章通过实验给出了城区双侧高边坡条件下，多排硐室微差松动爆破的设计原理及施工经验。     

12kV真空断路器灭弧室结构对电场分布影响的仿真研究

本文采用COMSOL有限元软件研究了均压屏蔽罩、主屏蔽罩以及触头开距对真空灭弧室电场、电位分布的影响。结果表明:主屏蔽罩端部、动静触头端部和主屏蔽罩与触头之间的区域是场强集中处,是最容易产生击穿放电的位置,也是真空灭弧室绝缘结构优化设计的关键部位。改善真空灭弧室内部结构的对称性可以使电场分布更加均匀;主屏蔽罩端部卷边方向朝内侧,能够将场强最大值从触头附近转移到主屏蔽罩端部附近,有利于触头电弧熄灭;主屏蔽罩端部卷边半径设置为3 mm、卷边角度设置为90°,有利于降低场强最大值;主屏蔽罩坡度设置为15°能够使触头附近的场强减小;主屏蔽罩半径设置为50 mm、总长度设置为110 mm较为合适;增大触头开距可以减小灭弧室内部的电场强度,但灭弧室内部的电场分布几乎不变。本文的研究结果可为真空灭弧室的小型化设计提供理论依据。     

The Effect of External Magnetic Field on a Vacuum Arc

The effect of an external longitudinal magnetic field on the time required for anode spot formation in a high-current (5 to 12 kA) vacuum arc is experimentally studied, and the minimal value of a magnetic field inhibiting the anode spot formation is determined. The experimental results are compared with theory. The phenomenon of break of current in a low-current (100 to 300 A) vacuum discharge upon superposition of a magnetic field with transverse component on the discharge is investigated. The probability of break of current increases with the magnetic field. The possible mechanism of break of current is discussed.     

一种基于主成分分析的TDLAS高频噪声滤波

针对TDLAS高温测量时,吸收光谱容易受到探测器和硬件电路高频噪声干扰,进而影响温度测量准确度和探测灵敏度等问题,提出了一种基于主成分分析的去噪方法。首先将原始吸光度列向量进行矩阵化排列;然后通过主成分分析将其分解为主成分矩阵和得分矩阵;取合适的主成分数,利用截取部分主成分矩阵和得分矩阵重构原始数据,其中截留的主成分代表原始数据主要信息,而剔除的部分仅包含噪声信息。实验结果表明该方法用于TDLAS测量水蒸气温度,噪声去除率达81%,温度解算标准差从8.9降至5.3。     

The Movement of an Ion-exchange Microparticle in a Weak External Electric Field

The electrokinetic motion of spherical particle suspended in the electrolyte solution under influence of external electric field is studied. Due to impermeability of particle’s surface for one kind of ion species the particle exhibit behavior different to well investigated dielectric particles. Under an assumption of a weak external electric field, we derive the analytical estimation of the particle’s velocity by means of a method of matched asymptotic expansions. The analytical analysis is complemented by numerical solution, which gives the distribution of ion’s concentrations, electric potential profiles and flows streamlines. The analytical results are successfully compared with the results of numerical simulation.     

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.     

Entanglement and Entropy Squeezing for Moving Two Two-Level Atoms Interaction with a Radiation Field

In this paper, we analyzed squeezing in the information entropy, quantum state fidelity, and qubit-qubit entanglement in a time-dependent system. The proposed model consists of two qubits that interact with a two-mode electromagnetic field under the dissipation effect. An analytical solution is calculated by considering the constants for the equations of motion. The effect of the general form of the time-dependent for qubit-field coupling and the dissipation term on the temporal behavior of the qubit-qubit entanglement, quantum state fidelity, entropy, and variance squeezing are examined. It is shown that the intervals of entanglement caused more squeezing for the case of considering the time-dependent parameters. Additionally, the entanglement between the qubits became more substantial for the case of time dependence. Fidelity and negativity rapidly reached the minimum values by increasing the effect of the dissipation parameter. Moreover, the amount of variance squeezing and the amplitude of the oscillations decreased considerably when the time dependence increased, but the fluctuations increased substantially. We show the relation between entropy and variance squeezing in the presence and absence of the dissipation parameter during the interaction period. This result enables new parameters to control the degree of entanglement and squeezing, especially in quantum communication.     

Controlled Vacuum Breakdown in Carbon Nanotube Field Emission

We report a physical mechanism of controlling vacuum breakdown in field emission from carbon nanotubes (CNTs). The thermal evaporation or runaway of CNT emitters is considered to be responsible for destructive vacuum breakdowns due to an overcurrent through electronically shorted circuits, where misaligned or irregularly long CNT emitters were found. The occurrence of the destructive breakdown, however, could be under control after an electrical treatment using soft breakdowns. Significant improvements of field emission stability and uniformity were achieved by optimally controlled soft breakdowns, which eliminated the short circuits and recovered the field emission with no destruction of electrodes.     

The Local Electric Field in Photorefractive and Other Semi-insulating Materials

Abstract

Debye-Huckel theory is applied to determine the local electric field around a dipole in a photorefractive semi-insulating material. The dipole can be either induced, as in the presence of an electric field, or permanent. It is shown that when the Debye screening length is large, the local electric field E is given by E_M(? + 2)/3, where E _M is the macroscopic electric field. On the other hand, when the Debye screening length is small, the local electric field is equal to the macroscopic electric field.     

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.     

The Effects of Electric Field on a Triangular Bound Potential Quantum Dot Qubit

On the condition of electron-LO-phonon strong coupling in a triangular bound potential quantum dot, we obtain the eigenenergy and eigenfuctions of the ground state and the first-excited state by using the Pekar type of variational method. This two-level system in a quantum dot can be employed as a qubit, which is a basic unit for quantum information operation and storage. Our numerical results indicate that the oscillation period of this qubit is an increasing function of the confinement length and the electric field. The influence of electric field on the period of oscillation becomes greater when the confinement length is increased. The electron probability density of the qubit is an increasing function of the electron-LO-phonon coupling constant. On the contrary, it is a decreasing function of the electric field. Meanwhile, the electron probability density varies periodically with the polar angle.     

A Two-Dimensional Mathematical Model of a Short Vacuum Arc in External Magnetic Field

A mathematical model of a short high-current vacuum arc is developed. The model involves equations of motion and continuity for electrons and ions, as well as electrodynamic equations. The boundary conditions are formulated on the cathode and anode boundaries of plasma and on the side surface of plasma. The model is based on the method of trajectories, in the case of which a set of partial equations can be reduced to a set of ordinary differential equations written for derivatives along ion trajectories. The model is used to determine the region of steady-state solutions and to calculate the distribution of the parameters of arc plasma in this region.     

Electric Field Gradient Theory with Surface Effect for Nano-Dielectrics

The electric field gradient effect is very strong for nanoscale dielectrics. In addition, neither the surface effect nor electrostatic force can be ignored. In this paper, the electric Gibbs free energy variational principle for nanosized dielectrics is established with the strain/electric field gradient effects, as well as the effects of surface and electrostatic force. As regards the surface effects both the surface stress and surface polarization are considered. From this variational principle, the governing equations and the generalized electromechanical Young-Laplace equations, which take into account the effects of strain/electric field gradient, surface and electrostatic force, are derived. The generalized bulk and surface electrostatic stress are obtained from the variational principle naturally. The form are different from those derived from the flexoelectric theory. Based on the present theory, the size-dependent electromechanical phenomenon in nano-dielectrics can be predicted.     

Intensification of the Electric Convection of Weakly Conducting Liquids by a Pulsed Electric Field

Results of an investigation of the kinematic characteristics of the electric convection of weakly conducting liquids intensified by a pulsed electric field are reported.     

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 Distribution in Multilayer Thin-film Polarizers

Abstract

The distribution of electric-field amplitude inside multilayer thin-film polarizers is evaluated for various polarizer designs. The polarizers, based on (H/2, L, H/2) as the basic stack, show higher field amplitude than those based on all quarter-wave layers. Here H and L represent quarter-wave layers of high- and low-index materials respectively. It has been pointed out that, to avoid damage to the polarizers in high-power laser systems, it is necessary to know the field distribution inside the layers both for radiation incident from the air-multilayer interface as well as the glass-multilayer interface. Some implications of the positioning of thin-film polarizers in Faraday isolators used in high-power laser chains are discussed in relation to the susceptibility of these polarizers to optical damage. The results indicate that the liquid-prism MacNeille polarizer shows a higher damage threshold, which can possibly be further improved by increasing the angle of incidence at the multilayer.     

The Electrical Conductivity of a Fully Ionized Magnetic Plasma with Screened Interaction between Charges

The method of solving the kinetic Boltzmann equation is used to calculate the electrical conductivity of a fully ionized plasma with screened interaction between charges, located in a time-constant external magnetic field. The dependence of the longitudinal, transverse, and Hall conductivity on the nonideality parameter of the plasma and on the parameter _{e 0} is established. It is demonstrated that the maximum (modulo) value of the Hall components of plasma conductivity shifts towards lower values of the intensity H of external magnetic field as the nonideality parameter increases.