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聚变装置超导磁场环境下真空测量电离规因灯丝变形、带电粒子轨迹变化等物理机制导致真空测量精度不高,不能满足工程精确测量的需求。基于磁屏蔽的理论,构建了半封闭式和开放式的两种多层磁屏蔽结构模型,利用Maxwell有限元软件,仿真研究了结构材料层不同厚度和不同磁场方向等条件下磁屏蔽效能的变化规律。结果表明,屏蔽效能随铁层材料径向厚度的增加而增大,铁层材料端部厚度对其影响较小;超导材料层厚度对屏蔽效能影响较小;磁场方向角在0°~90°范围内,屏蔽效能先减后增,并在90°(屏蔽结构轴向与磁场方向平行)时达到最大值。为电离规在复杂磁场应用条件下的屏蔽结构工程设计提供了依据。 相似文献
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夏明 《中国新技术新产品》2019,(15)
电力变压器对输电网络中的电压高低和稳定都至关重要,为了改变温升等问题对变压器工作效率、质量的影响,我们引入了磁屏蔽这一手段,并且通过分析磁屏蔽对电力变压器的磁场的影响,分析不同位置,不同厚度的磁屏蔽对温升的影响,散热系数的区别,仔细探究磁屏蔽对电力变压器温升的具体影响,对电力变压器设计进行优化,降低不利影响,完善电力变压器设计。 相似文献
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基于条纹对比度的三维测量方法由于具有垂直测量的特点,可用于测量表面有突变的复杂物体的三维信息.本文在现有方法的基础上,提出了一种改进的基于条纹对比度的三维测量方法.该方法利用投影仪将一组相移的正弦条纹依次投射在被测物体上,并使被测物体位于投影仪成像面的前方,CCD相机通过一个半透半反镜从投影方向获取物体表面的条纹图像,... 相似文献
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本文建立了两种不同铁芯结构的纵向磁场真空灭弧室触头三维模型,一种铁芯为带有断口的环状结构,另一种是由12个柱状铁芯圆周方向排列的结构,采用有限元分析方法对两种结构的三维模型进行仿真计算,分析对比两种铁芯结构对电流峰值时刻纵向磁场和电流过零时剩余磁场以及磁场滞后时间的影响,计算的过程中考虑到了涡流的影响。从仿真结果中可以得到以下结论:1.电流峰值时环状铁芯结构产生的纵向磁场大于柱状铁芯结构,但柱状铁芯结构产生的纵向磁场比环状铁芯结构的均匀;2.电流过零时两种铁芯结构的剩余磁场分布相似,但环状铁芯结构的剩余纵向磁场大于柱状铁芯结构;3.柱状铁芯结构的磁场滞后时间要小于环状铁芯结构,电流过零时剩余磁场强的区域对应的磁场滞后时间也大。 相似文献
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本文介绍了利用光截面发射器、单CCD摄像机和双定向技术实现物体表面三维自动测量的系统.文中叙述了系统的组成和测量原理,详细介绍了利用控制板的单CCD摄像机双定向技术,将三维问题简化为两次二维求解的解算过程,空间三维坐标的自动解算和实物模型的量测等.系统中使用的直接线性变换(DLT)方法具有形式简单、方便实用、解算稳定可靠的特点,在解算过程中无需相机的内外方位元素.系统所用的方法是单CCD摄像机进行物体表面三维自动测量的新途径. 相似文献
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A novel approach for analyzing conducting shields of extremely low frequency magnetic fields in linear media is presented. It consists of an integral formulation based on the cell method, expressed in terms of network-like loop currents and magnetic vector potential line integrals on the shield surface. This formulation leads to a considerable reduction of field problem variables, thus limiting the amount of allocated memory and speeding-up the numerical procedure compared to other differential and integral techniques. Eddy currents are computed first, then the magnetic vector potential and the magnetic flux density distributions are evaluated by applying the superimposition principle. A detailed comparison between this method and a three-dimensional finite element method code demonstrates the accuracy of the results and the advantages of the method. 相似文献
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Meruzhan Kerobyan Anna Gyulasaryan Suren Soghomonyan Gevorg Gabrielyan Stepan Essaian 《Journal of Modern Optics》2013,60(10):808-813
A method for measuring parallelism of transparent optical components with small aperture size is described. It uses a Haidinger-type laser interferometer adapted for the measurement of optical components with millimeter and sub-millimeter aperture size. The method is based on the measurement of the optical thickness variation when the plate under test is translated across a focused laser beam. Measurement results for optical parts with 0.8 mm–10 mm aperture size are presented. 相似文献
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We present a simple method to determine precisely the specular reflectance of optical components. The absence of transmissive elements in this method makes a wide spectral range available. High accuracy and precision are achieved with a fast, periodic change between the reference beam and the probe beam. Special efforts were made to eliminate inhomogeneities of beam intensity and detector sensitivity. With our experimental setup we obtain a precision of ±3 × 10(-4) at the wavelength of 10.6 μm and ±3 × 10(-5) at 1.06 μm for a single-bounce-measuring setup. 相似文献
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The authors propose a novel method of magnetic shaking for enhancing the performance of ferromagnetic shielding. The method employs a new type of planar coil which generates higher-order multipole fields. Ferromagnetic shielding walls placed close to the planar coil can be suitably shaken by its field, whereas unwanted leakage of the shaking field into the shielded space can be avoided due to the highly localized nature of the multipole field. The configuration of the novel planar coil is similar to a square mesh in which alternating cells are clockwise or counterclockwise current loops. The shaking effect on the shielding performance and the leakage of the shaking field are evaluated using cylindrical shields and compared with results obtained with toroidal shaking coils 相似文献
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Electromagnetic interference shielding characteristics and shielding effectiveness of polyaniline-coated films 总被引:1,自引:0,他引:1
The study aims to investigate the electromagnetic interference (EMI) shielding characteristics and shielding effectiveness (SE) of polyaniline (PANI)-coated films. Free-standing films of emeraldine salt were obtained by PANI-emeraldine base with dode-cylbenzensulfonic acid on a polyethylene terephthalate film. The four-point probe method was employed to measure the electrical resistivity for investigating the electromagnetic characteristics of PANI-coated films. In addition, the SE of the PANI-coated films was measured in two different ways: a flanged coaxial shielding effectiveness test and a shielding effectiveness on the testbed having a box-type chamber equipped with instruments for electromagnetic shielding testing under real conditions. The overall SE measured from experiments was also compared with the approximate SE value calculated from a theoretical method. The present study has shown the possibility of utilizing PANI-coated films as EMI shielding/absorption materials. 相似文献