新型电场传感器应用于输电线电场测量

基于高性能的微电子机械系统(MEMS)工频电场传感器系统开展了高压架空输电线下电场测量应用研究.为了获得电场分布规律,基于模拟电荷法,建立了输电导线的二维电场计算通用模型.传感器系统核心敏感芯片基于电荷感应原理,采用MEMS技术加工制作.在0~1000kV/m工频电场范围内,传感器系统的总不确定度为1.53%,分辨力达到了20V/m.仿真与测试结果表明:35kV与10kV输电线下的电场计算结果与传感器系统的测量结果偏差分别为6%和10%,并与传统的Narda EFA-300电磁场分析仪测量结果具有较好的一致性.     

Algebraic and geometric invariant of a pair of non-coplanar conics in space

It is easy to construct the geometric invariant of a pair of non-coplanar conics in space. It is the crossratio of the 4 intersection points of the two conics with the common line of the two conic planes. In this paper, the algebraic invariant of a pair of non-coplanar conics is derived from the invariant algebra of a pair of quaternary quadratic forms by using the dual representation of space conics. Then, the relationship between the algebraic invariant and the geometric invariant is established.     

Transport control in fusion plasmas by changing electric and magnetic field spatial profiles

For magnetically confined plasmas in tokamaks, we have numerically investigated how Lagrangian chaos at the plasma edge affects the plasma confinement. Initially, we have considered the chaotic motion of particles in an equilibrium electric field with a monotonic radial profile perturbed by drift waves. We have showed that an effective transport barrier may be created at the plasma edge by modifying the electric field radial profile. In the second place, we have obtained escape patterns and magnetic footprints of chaotic magnetic field lines in the region near a tokamak wall with resonant modes due to the action of an ergodic magnetic limiter. For monotonic plasma current density profiles we have obtained distributions of field line connections to the wall and line escape channels with the same spatial pattern as the magnetic footprints on the tokamak walls.     

Dispersion in electroosmotic flow generated by oscillatory electric field interacting with oscillatory wall potentials

An analytical study is presented in this article on the dispersion of a neutral solute released in an oscillatory electroosmotic flow (EOF) through a two-dimensional microchannel. The flow is driven by the nonlinear interaction between oscillatory axial electric field and oscillatory wall potentials. These fields have the same oscillation frequency, but with disparate phases. An asymptotic method of averaging is employed to derive the analytical expressions for the steady-flow-induced and oscillatory-flow-induced components of the dispersion coefficient. Dispersion coefficients are functions of various parameters representing the effects of electric double-layer thickness (Debye length), oscillation parameter, and phases of the oscillating fields. The time–harmonic interaction between the wall potentials and electric field generates steady as well as time-oscillatory components of electroosmotic flow, each of which will contribute to a steady component of the dispersion coefficient. It is found that, for a thin electric double layer, the phases of the oscillating wall potentials will play an important role in determining the magnitude of the dispersion coefficient. When both phases are zero (i.e., full synchronization of the wall potentials with the electric field), the flow is nearly a plug flow leading to very small dispersion. When one phase is zero and the other phase is π,?the flow will be sheared to the largest possible extent at the center of the channel, and such a sharp velocity gradient will lead to the maximum possible dispersion coefficient.     

Generation of picosecond radiation by semiconductors under electric field and electron beam pulses

The results of characteristic’s investigation of the compact ps light generator are represented. Generator consists of two main components—high voltage pulse generator and a laser head (coaxial camera with electrodes and semiconductor target). High voltage and e-beam pulse’s influence on monocrystal ZnSe and CdS targets was investigated in pressure range from 10⁻¹ to 5 torr. It was shown that pressure increase leads to e-beam pulse duration shortening. The output power of ZnSe (480 nm) and CdS (525 nm) targets in lasing regime has exceeded 10 kW at room temperature.     

Lift-off of a conducting sessile drop in an electric field

A conducting drop in partial wetting regime, placed on the lower electrode of a parallel-plate capacitor and surrounded by a dielectric fluid, is considered. The drop, initially flattened by gravity, is elongated by the electrostatic force and possibly lifts-off when a uniform DC electric field is applied. The electrostatic force and the lift-off condition were calculated in two previous articles, respectively, for undeformable and for slightly deformable drops in the absence of gravity (zero Eötvos number). In this paper, numerical models are put to work to study accurately the complex lift-off process resulting from the competition between gravitational, electrical and capillary forces. Large deformations of the drop surface at any value of the Eötvos number may be addressed by such a numerical procedure. Computational results allow assessing the accuracy and limits of previous analytical and asymptotic relations.     

Minimal state space search in parallel production systems

A methodology for transforming the original search space into an equivalent but minimal search space is proposed. First, the concept of dependences leads to a procedure for reduction of the search space. The search procedure using this method can produce a minimal and complete search space. It is shown that this method is applicable to parallel search as well. An added advantage of this method is that it does not exclude the use of heuristics. π-λ transformation is introduced to reduce the parallel search space     

用于空间的三反射镜光学系统设计

现代空间光学的发展需要很大的线视场、像质接近衍射极限或很大相对口径的无中心遮拦反射系统。能满足这些要求的非三反射系统莫属,虽然现在已有功能十分齐全的光学系统自动优化软件,但求出一个合理的初始结构尺寸还是十分重要的。文章主要探讨了用于空间的三反射镜光学系统设计方法。     

Control of head smear generation by diamond-like carbon films using an external electric field

Microsystem Technologies - The formation of head smears in heat-assisted magnetic recording is a significant problem that must be addressed to ensure the reliability of the head-disk interface. In...     

Electrokinetically driven concentration of particles and cells by dielectrophoresis with DC-offset AC electric field

Insulator-based dielectrophoresis (iDEP) has been successfully used for on-chip manipulations of biological samples. Despite its effectiveness, iDEP typically requires high DC voltages to achieve sufficient electric field; this is mainly due to the coupled phenomena among linear electrokinetics: electroosmosis (EO) and electrophoresis (EP) and nonlinear electrokinetics: dielectrophoresis (DEP). This paper presents a microfluidic technique using DC-offset AC electric field for electrokinetic concentration of particles and cells by repulsive iDEP. This technique introduces AC electric field for producing iDEP which is decoupled from electroosmosis (EO) and electrophoresis (EP). The repulsive iDEP is generated in a PDMS tapered contraction channel that induces non-uniform electric field. The benefits of introducing AC electric field component are threefold: (i) it contributes to DEP force acting on particles, (ii) it suppresses EO flow and (iii) it does not cause any EP motion. As a result, the required DC field component that is mainly used to transport particles on the basis of EO and EP can be significantly reduced. Experimental results supported by numerical simulations showed that the total DC-offset AC electric field strength required to concentrate 15-μm particles is significantly reduced up to 85.9% as compared to using sole DC electric field. Parametric experimental studies showed that the higher buffer concentration, larger particle size and higher ratio of AC-to-DC electric field are favorable for particle concentration. In addition, the proposed technique was demonstrated for concentration of yeast cells.     

箭载电场数据处理软件设计

本文介绍了对箭载电场仪数据的处理及分析软件。该软件是将电场仪及其搭载设备所提供的原始数据转换成可用的子午工程数据产品,主要实现原始科学数据的格式转换和附加电场的处理。文章阐述了数据处理方法及软件的具体功能,以及软件设计的核心算法,该系统功能完善。     

Entanglement of magnetic impurities through electron scattering in an electric field

We show that the entanglement between two distant magnetic impurities, generated via electron scattering, can be easily modulated by controlling the magnitude of an applied external electric field. We assume that the two magnetic impurities are fixed and located on an one-dimensional quantum wire. A ballistic electron moving through the wire is scattered off by both impurities, so the electron spin can be seen as a mediator between the spins of the impurities. Heisenberg operators are used to describe the interactions between electron and impurities spins. We use a wave guide formalism to model the ballistic electron wave function. Entanglement control is shown to be possible for three different protocols of entanglement detection. The effect of detection protocols on the entanglement extraction is discussed.     

Rotational regimes of freely suspended liquid crystal films under electric current in presence of an external electric field

The electrohydrodynamic (EHD) vortices produced by an electric current in freely suspended liquid crystal (LC) films of N-(4-methoxybenzylidene)-4-butylaniline (MBBA), convert to a pure rotation in the presence of external electric field ( $\it{E}_{{\rm ext}}$ ) perpendicular to the current direction. Here, the direction and strength of the rotation are precisely under control by our self-made device called ??liquid-film motor??. In this paper, we present experimental observations of the EHD fluid flow when external electric field varies from zero to a value in which pure rotation on the liquid crystal (LC) film is observed. We also show experimentally that the presence of external electric field causes a great decrease in the current produced by the voltage V _J required for observing EHD vortices in freely suspended films of MBBA. The LC films begin to rotate when E _ext V _J reaches a threshold value. This threshold is investigated experimentally as a function of voltage V _J and the external electrical field $\it{E}_{{\rm ext}}$ .     

Child–robot interaction mediated by building blocks: from field observations in a public space

This study attempts to describe children's behavior from the viewpoint of microscopic adjustment of actions when they encounter an oddly shaped robot, called “Muu.” We investigated this through field observations at a workshop in a children's museum. Children of various ages and their parents participated in the workshop together. They were instructed by an experimenter to play with building blocks while talking with Muu. As a result, it was found that the children and the robot could establish rich communications with each other not when the children evaluated Muu's behavior, but when Muu evaluated the children's work. This indicates that the robot could become an “other” that might interact with children mediated by the building blocks, whereas many children and parents treated it as a “toy,” just as the building blocks were considered merely as “objects” during interactions. This work was presented in part at the 10th International Symposium on Artificial Life and Robotics, Oita, Japan, February 4–6, 2005     

Vacuum polarization by a scalar field in de Sitter spacetime in the presence of a global monopole

We analyze vacuum polarization effects associated with massive scalar quantum fields in a higher-dimensional de Sitter space in the presence of a global monopole. Because this analysis has been developed in pure de Sitter space, we are mainly interested on the effects induced by the presence of the global monopole. So, to achieve this objective, we calculate the corresponding Wightman function, which is expressed in an integral representation and explicitly depends on the parameters associated with the presence of the monopole and the cosmological constant. Admitting that the former is closed to unity, which corresponds to a realistic value predicted by Grand Unified Theories, it is possible to express this function as a sum of two terms: the first one corresponds to the Wightman function on the bulk where the global monopole is absent, and the second one is a contribution induced by the presence of the monopole.     

Mathematical model of the coordinate-sensitive photodetector with control electric field

Design principles for of a mathematical model of the semiconductor photodetector meant for the operation in specialized computer vision systems in optical section scanning are stated. Is composed a system of equations with partial derivatives describing physical processes in separate constructively prescribed segments of the photodetector structure. The general solution is obtained as a superposition of partial solutions relating to different combinations of physical actions on the structure—external light and internal electric fields—on these segments. Families of computed and experimentally obtained output coordinate characteristics of the photodetector are given. The adequacy of the model is confirmed by the similarity of these characteristics. The model can be used on different stages of projecting and operating for photodetectors of this class.     

电场侵入式理疗仪的设计与实现

设计了一款术后康复理疗仪,以生物安全型高频信号源为理疗信号,在深层进行电能与生物热能的转换。该理疗仪由电极、高频生物安全型信号源、嵌入式微控制器和电源组成。采用WinCE操作系统,应用分级式脉宽控制算法对信号频率与强度进行智能控制。测试表明,该理疗仪电磁兼容性好,安全性高,理疗效果明显。     

电场感应式料流传感器设计

针对现有开关式和压力式料流传感器存在易磨损、可靠性差的问题,设计了一种电场感应式料流传感器。该传感器采用内置电场感应式智能芯片作为感应元件监测电场电参数,利用单片机采集和处理电场电参数,通过电参数变化经内部数据处理输出胶带有料、无料信号。现场实验结果表明,该传感器能够准确检测运动或者静止的胶带上有无物料,完全满足现场实际应用的需求,具有非接触检测、无磨损、使用寿命长、信号稳定可靠的特点。     

PLC在零度带束层生产线电气改造控制系统中的应用

主要阐述了用OMRON公司的C200H可编程控制器（PLC）对汽车轮胎生产过程中的零度带束层生产线进行电气改造的工艺及原理。并对整个控制系统的设计进行了介绍。