Characterization of the polarization sensitivity anisotropy of a near-field probe using phase measurements

Amplitude and phase measurements of the near-field generated by isolated subwavelength apertures in a gold film are presented. The near-field distribution of such a structure is complex and the measured signal strongly depends on the electric field components effectively detected by the experimental setup. By comparing this signal with 3D vectorial calculations we are able to determine which electric field components are effectively measured. The sensitivity of the phase distribution is key to this measurement. The proposed characterization technique should prove extremely useful to calibrate a Scanning near-field optical microscopy (SNOM) beforehand in order to retrieve quantitative information on the polarization of the field distribution under study.     

带有两个非共线裂纹载流薄板的温度场

对于带有两个非共线直线裂纹的无限大载流薄板,当在无穷远处通人均布电流时,由于在裂纹尖端出现绕流和焦耳热集中效应,使裂纹尖端熔化形成焊口,而达到止裂的目的。寻找电流密度与裂纹尖端处热源功率之间的关系,板内温度场的分布状态、裂纹前缘温度值等等,是推广应用电磁热效应对导电体实施裂纹止裂的关键问题。文中采用“伪电流”和“伪热流”的方法,分别得到通电后域内的电流密度分布及温度分布,给出上述问题的解析解,并给出算例。     

拉盖尔-高斯光经超表面的聚焦特性

为了研究椭圆偏振拉盖尔-高斯光经超表面的聚焦特性,重点分析了聚焦光场的电场强度以及相位分布特性。利用时域有限差分(FDTD)方法仿真椭圆偏振拉盖尔-高斯光经超表面的聚焦光场。研究表明,椭圆偏振拉盖尔-高斯光经超表面聚焦后会在聚焦光场的纵向分量电场中出现自旋角动量转化为轨道角动量的现象,通过改变超表面的数值孔径大小、拉盖尔-高斯光的偏振类型等参数可以调控涡旋光场形态分布。该现象可应用于光镊、量子加密、光学扳手等技术中。     

基于渡越-切伦科夫辐射原理太赫兹横向场频率特性的实验研究

基于渡越-切伦科夫辐射原理,单色飞秒激光脉冲聚焦到空气中形成等离子体进而辐射出径向偏振太赫兹波,径向偏振太赫兹波经过紧聚焦后在焦点处产生太赫兹波横向偏振分量。为了有效调控太赫兹横向分量的频率分布和振幅特性,首先,通过理论分析太赫兹横向场分量在外加电压下的分布规律,给出不同角度的外加电压对太赫兹横向场频率强度的影响。然后,采用对等离子体施加外部电场的方法,得到一个最佳的纵向电场角度产生高强度太赫兹横向偏振分量。对发展太赫兹波特性的基础研究以及太赫兹技术的应用具有重要的参考意义。     

某车载翻转平台设计

为满足某电磁场强测试设备需要,同时实现多套天线的波束指向一致性要求,设计了一种翻转平台。在某测试系统中,以车载电动翻转平台为载体,通过驱动车载电动翻转平台,采用包括电动调平、伺服控制、电动升降以及自动锁定等多个动作流程,实现天线波束指向的改变及稳定工作。避免了软波导、天线座的使用,可大大降低系统制造费用,提高系统有效辐射功率和系统可靠性。通过理论分析计算与软件仿真,对主要受力部件进行了强化设计,保证了翻转平台的可靠性和稳定性。     

Electro-elastic fields of piezoelectric materials with an elliptic hole under uniform internal shearing forces

The existing investigations on piezoelectric materials containing an elliptic hole mainly focus on remote uniform tensile loads. In order to have a better understanding of the fracture behavior of piezoelectric materials under different loading conditions, theoretical and numerical solutions are presented for an elliptic hole in transversely isotropic piezoelectric materials subjected to uniform internal shearing forces based on the complex potential approach. By solving ten variable linear equations, the analytical solutions inside and outside the hole satisfying the permeable electric boundary conditions are obtained. Taking PZT-4 ceramic into consideration, numerical results of electro-elastic fields along the edge of the hole and axes, and the electric displacements in the hole are presented. Comparison with stresses in transverse isotropic elastic materials shows that the hoop stress at the ends of major axis in two kinds of material equals zero for the various ratios of major to minor axis lengths; If the ratio is greater than 1, the hoop stress in piezoelectric materials is smaller than that in elastic materials, and if the ratio is smaller than 1, the hoop stress in piezoelectric materials is greater than that in elastic materials; When it is a circle hole, the shearing stress in two materials along axes is the same. The distribution of electric displacement components shows that the vertical electric displacement in the hole and along axes in the material is always zero though under the permeable electric boundary condition; The horizontal and vertical electric displacement components along the edge of the hole are symmetrical and antisymmetrical about horizontal axis, respectively. The stress and electric displacement distribution tends to zero at distances far from the elliptical hole, which conforms to the conclusion usually made on the basis of Saint-Venant’s principle. Unlike the existing work, uniform shearing forces acting on the edge of the hole, and the distribution of electro-elastic fields     

碳纤维电热元件辐射强度分布的数值模拟

建立碳纤维电热辐射管辐射强度分布的数学模型,基于MATLAB软件模拟不同类型碳纤维电热元件的辐射强度分布,并讨论其空间辐射特性。模拟结果表明：结构参数对碳纤维电热元件辐射强度分布的影响较大,随管径的变化,空间辐射强度存在一个最佳值,辐射强度分布的不均匀性随管径的增加而增加。对比不同类型电热元件的辐射强度分布特性,相同规格电热元件的辐射强度分布场基本一致,而辐射强度值随元件类型而变化。碳纤维电热元件的辐射强度明显高于普通金属加热元件,并且双侧涂覆红外涂料可使其辐射强度明显地提高。调整涂料的配方可以改变红外辐射的频谱分布以满足特殊的加热要求。试验证明：测试数据与模拟结果基本一致,为后期辐射场的设计提供了依据。     

Consumer load measurement in automated buildings

Diminishing fossil fuel supplies accompanied by rising prices is increasingly leading to consumer awareness regarding their energy consumption. With the intent to prepare for diminishing primary energy sources, sustainable alternatives (e.g. energy gained through wind or solar power and trends towards smart grids) have been introduced and found wide application. With the application of intelligent solutions, the energy consumption in buildings can be reduced significantly. One basis for these solutions, such as load and energy management for optimized energy distribution and saving, is the energy metering of components in electric systems. This contribution shall present a field bus system that, due to its local distribution and system architecture, is suitable for energy consumption measurement of its individual components. After presenting the SmallCAN bus system and its concept, a summary of the mathematic algorithm and an example application will be shown to exemplify the functionality.     

智能配电网技术在油田智慧矿区建设中的应用

油田矿区智能配电网改造建设是智慧矿区建设的重要组成部分,智能配电网的自愈控制系统是保证矿区配电网实现智能化运行的重要环节,对智能配电网技术的应用及在智慧矿区建设中的基础作用、系统接入方式、数据共享方式和信息互动方式做了较为深入的研究和方案设计。智慧矿区是数字城市与物联网相结合的产物,通过智能计算和感知测控技术的应用,使矿区配电系统与矿区管理、居民服务、公用事业和公众安全等矿区业务所组成的关键基础设施组件和服务相互联,使其更加高效和智能。     

基于Wi-Fi通信的工频电场测量系统设计

现有的工频电场测量仪通常采用光纤作为数据传输介质,光纤系统结构复杂、成本较高。测量人员手持终端与电场探头之间由光纤连接,无法实现人机分离,给测量带来不便。该文设计了一种基于Wi-Fi通信的工频电场测量系统,通过Wi-Fi无线连接方式实现工频电场测量数据的传输,可避免因测量人员离测量点太近而带来的电场畸变影响,保障现场工频电场测量的准确性。工频电场测量结果可以在现场带有Wi-Fi功能的移动终端上显示,也可以上传至云服务器,供后台工作人员实时监测和分析,实现人机分离以及数据的不间断传输。     

高阻抗电弧炉的电气特性研究

阐述了高阻抗电弧炉的组成、原理、电气运行特性及工程应用实例.现场运行数据表明这种技术可以有效提高炼钢生产率及降低电耗.     

飞行时间质谱宽能量聚焦反射器设计

离子的能量分散是影响飞行时间质谱分辨率的主要因素之一。本研究在Vlasak提出的宽能量聚焦反射器设计方法的基础上,通过同时优化飞行时间反射器各电极间的距离和电压的方法,使宽能量分布的离子具有更好的时间聚焦性能,并采用SIMION软件建立的仿真模型验证该方法的有效性。理论计算和仿真实验表明,本设计方法对极板加工和装配的误差可通过微调极板电压补偿,这有效地降低了仪器研制过程中的机械加工和装配精度的要求,从而进一步提高了方法的实用性。     

Evaluation of major historical ICR cell designs using electric field simulations

In Fourier-transform ion cyclotron resonance mass spectrometry, ions are detected by measuring image current induced in the detecting electrodes by trapped ions rotating in a magnetic field at their cyclotron frequencies. The ion trap used for this purpose is called the Penning trap. It can have various configurations of electrodes that are used to create a trapping electric field, to excite cyclotron motion, and to detect the induced signal. The evolution of this type of mass spectrometry is mainly driven by progress in the technology of superconducting magnets and in the constantly improved design of the ion cyclotron resonance (ICR) measuring cell. In this review, we focus on ICR cell designs. We consider that the driving forces of this evolution are the desire to increase resolution, mass accuracy and dynamic range, as well as to adapt new methods for creating and trapping ions.     

Measurement and simulation of the voltage distribution and the electric field on a glass insulator string

The electric field and voltage distribution in glass insulators used to support high-voltage lines are very important for their performance. In this paper, a 150 kV glass insulator was simulated. A three-dimensional electric field analysis program has been used for the calculations. The electric field and potential distributions in the vicinity of the insulator was examined. Finally, in order to validate the accuracy of the method, the simulation results were compared to corresponding experimental results with satisfactory agreement. The small deviation between the simulation and the experimental results shows that the simulation methodology is a useful tool for the calculation of the potential in this problem.     

一种基于负熵的舰船轴频电场信号检测方法

轴频电场是运动舰船在海水中产生的一种重要的物理场,它具有明显的线谱特征,是很难被隐身的舰船特征信号。运用Q-Q图法和Epps-Pulley方法对实测的海洋环境电场的高斯性进行了检验,检验结果表明环境电场具有良好的高斯性,在此基础上,将负熵准则应用于舰船轴频电场信号检测中,利用目标信号和环境噪声在负熵域上的显著差别,使用浮动门限将目标准确地检测出来。实测数据的处理结果证明了方法的有效性和优越性。     

电沉积技术中象形阳极的形状设计

利用ANSYS有限元软件，通过电场分析和优化设计，对电沉积技术中所用的象形阳极进行了形状设计。以电铸某喷管为例，辅助人工干预的办法，得到了带有屏蔽段的优化象形阳极，使阴极电场强度(电流密度)分布的均匀性得到了改善。该设计方法可替代传统的经验设计方法。     

基于太赫兹波的高分辨率空间电荷测试方法及系统

空间电荷的特性及分布状态直接改变介质内部电场的强弱,严重影响器件的电学性能。近年来,纳米材料和微纳电子器件飞速发展,在纳米量级乃至更小尺度上探测和掌握空间电荷的特征信息成为亟待解决的问题。为此基于脉冲电声法基本原理,设计并实现了一种基于太赫兹波和弹光取样技术的空间电荷分布测试新方法。基于应力双折射效应原理,设计制作了弹光取样传感器,并测试了性能。搭建了空间电荷测试系统,对定制硅PN结试样进行了测试,空间电荷区宽度随偏置电压的变化规律与PN结基本电学特性吻合。该方法采用全光学技术手段,克服了传统电子测试技术对系统带宽的限制,实验结果表明,该测试方法可以有效且可靠地将空间电荷测试分辨率提升至纳米量级。     

电动汽车驱动电动机的电磁场强度分布及安全分析

随着纯电动汽车的发展,从电动汽车驱动电动机对外部环境产生的电磁场强度入手,分析了在汽车主要空间范围内,电动汽车用驱动电动机所产生的电磁场强度分布及安全问题。采用AnsoftMaxwell软件,建立其二维的有限元模型,在一定空间范围对电动机进行了有限元分析,通过仿真得到电动机在电动汽车的空间电磁场分布情况。仿真结果对电动汽车电磁安全的进一步优化设计与国家相关电磁安全标准的制定具有一定的参考价值。     

Immaterial tip concept by light confinement

It is shown that the combination of TM polarized coherent evanescent light beams can lead to ( x , y ) confined light distributions. Moreover, owing to the evanescent nature of the interfering beams, the spatial distribution of the square modulus of the electric field does not vary versus the z -distance. Such an energy distribution can be used as a virtual tip, allowing the scanning of a sample without any mechanical contact with it.     

转子静偏心状态下机床电主轴电磁力有限元分析

电磁振动是电磁直驱型机床电主轴不可回避的振动来源,为了抑制电磁振动需要探讨其电磁力的频谱特征。推导了三相异步电主轴的电磁力波计算公式,重点分析了转子偏心状态下的电磁力波特点。基于Ansoft电磁场计算软件,建立了某国产电主轴的电磁场有限元分析模型,获得了电主轴的运行特性曲线。研究了转子在不偏心和偏心状态下的电磁力频谱变化规律,结果表明,静偏心会使电磁力力波成分更为丰富; 偏心的增加不会影响电磁力的阶次和频率分布,但与不平衡磁拉力的幅值和低阶力波幅值成正相关关系,将加剧电主轴的振动。