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设计一种应用于中频真空电弧实验的外施纵向磁场励磁系统。该系统由中频电流互感器感应主回路电流,产生二次电流为亥姆霍兹线圈励磁,从而在线圈轴线中心处产生与主电流同相位的纵向磁场,模拟纵向磁场线圈触头产生的磁场,且磁场通过变比可调。首先从理论出发,建立亥姆霍兹线圈轴线中心处磁感应强度与二次电流的关系,详细介绍系统重要参数的设计过程。其次针对电流互感器铁心磁导率高且漏感小的特点,简化其等效电路,并经计算证明实验电流为最大时电流互感器的铁心未饱和,一次电流与二次电流的相位差满足设计要求。最后对励磁系统性能进行测试实验,在交流实验中,假设了回路电流的数学模型并根据实验数据求解磁感应强度,B/I值计算结果与理论值一致,验证了设计方法的有效性和实用性。 相似文献
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亥姆霍兹线圈及麦克斯韦线圈磁场分布及均匀性比较 总被引:1,自引:0,他引:1
基于毕奥-萨伐尔定律,运用椭圆积分,推导出圆环电流在空间任意一点产生的磁场公式,进而分析了亥姆霍兹线圈和麦克斯韦线圈在中心处磁场各分量的分布模型,绘出了空间分布。分析结果表明,麦克斯韦线圈磁场不均匀度小于0.0001的区域半径约是亥姆霍兹线圈的20倍。 相似文献
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该文研究了两种常见亥姆霍兹线圈产生磁场的均匀性,并根据装置线圈所产生磁场作用下的生物组织治疗温度分布分析了磁场均匀性对治疗效果的影响。其中,文中的磁纳米粒子(MNPs)以磁流体形式注射进肿瘤区域并假定以注射点为中心呈现高斯分布。该文在多种约束条件下应用改进粒子群算法优化了磁场的频率和强度、磁纳米粒子粒径,以及磁纳米粒子体积分数等参数,而涉及的约束条件包括治疗最高安全温度、治疗磁场安全范围上限、MNPs粒径范围,以及MNPs产热有效条件等。同时,该文以累积等效分钟数来评估圆形和正方形亥姆霍兹线圈及理想磁场在不同血液灌注率下的细胞热损伤程度。研究结果表明,正方形亥姆霍兹线圈相比于圆形线圈能产生更大范围的匀强磁场,这使其磁热疗效果更接近于理想磁场情况。同时,考虑温度依赖的血液灌注率相比定值情况具有更高的治疗温度。 相似文献
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We propose the novel magnetic compensation method which is suitable to compensate gradient magnetic fields. The method is to be applied to a conventional large-scale, tri-axial active magnetic shielding system such as a spacecraft magnetic testing facility. The essences of this method are the adoption of compensation coils which have degrees of freedom in their coil orientations, and their installation position, which is chosen to have certain distances from the center of the shielding area. The method works with at least four compensation coils. In this research, we actually demonstrated the method with a scaled-down experiment. Disturbance magnetic field (B) at the target zone was suppressed from 21.33 nT to −1.54 nT and magnetic field uniformity (ΔB) within the test zone was improved from 2.3 nT to 0.015 nT. In terms of magnetic field gradient, improvement from over 4 nT/m to below 0.5 nT/m was achieved. 相似文献
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通过对现有磁性磨粒光整加工设备的结构以及加工机理的分析总结,得出了使用电磁铁作为磁场源的磁性磨粒光整加工设备的磁场影响因素。利用Ansoft Maxwell 3D对线圈在磁轭磁芯回路中的三种不同布置位置的磁场分布进行了仿真计算,并对计算结果中磁感应强度分布场图和关键路径上磁感应强度分布曲线进行了对比分析,结果表明线圈布置在磁轭磁芯回路的两侧或者后侧时,加工间隙的磁感应强度较大。这种利用仿真计算软件指导磁场形成部件设计的方法,为磁场形成部件的设计提供了理论依据,为后续设计提供了更多的可行性方案。 相似文献
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To realize a general-purpose magnetic field sensor having a detection sensitivity of the order of 10?12 T/Hz at room temperature, a problem of removing the effect of the Earth's magnetism from the sensor must be solved because its magnitude is 4.5 × 104 times larger than that in the range to be detectable. For this purpose, a well-known approach of exciting the sensor in the opposite direction to the Earth's magnetism to cancel out the value has been adopted. This paper aims at realizing a magnetic field sensor free from the Earth's magnetism by introducing a method called “zero magnetic field.” In practice, such a sensor was developed and the tested results confirmed that the detection performance was maintained without losing the high sensitivity. 相似文献
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为了提高永磁磁轴承的轴向承载力和刚度,在对理想Halbach磁场进行分析的基础上,利用分段磁环构成的近似Halbach磁场设计了一个新型的轴向永磁磁轴承.通过有限元软件对这种磁轴承进行了建模仿真,计算了最大承载力以及刚度,并分析了磁环的厚度与高度比值对磁轴承刚度的影响.仿真结果表明,采用Halbach磁场的轴向磁轴承最大可以提供2×106N/m的刚度,高于相同永磁材料用量条件下传统轴向磁轴承的刚度.考虑到这种磁轴承的结构要比传统结构复杂,因此这种磁轴承更适合在对刚度要求高的场合应用. 相似文献
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Thermomagnetic instability in superconducting wires composing multistrand cables is a problem in the development of cables with large current capacity. This paper elucidates the quenching properties of ac superconducting wires in a distributed magnetic field applied to the strands in the cable, and the stabilization of the ac superconducting wires considering the effect of the longitudinal magnetic field or the fraction of copper embedded in each strand. First, the degradation of the quench current of CuNi/NbTi superconducting wires in a distributed magnetic field is exhibited with simple test samples. Second, the quench properties of the strand in a (6 + 1)3 cable and the optimal twist pitch of the cable for high stabilization are discussed. Last, the effect of copper on the quench properties of the strand and the appropriate fraction of copper for suppression of quench current degradation in a distributed magnetic field are discussed. © 2001 Scripta Technica, Electr Eng Jpn, 135(4): 26–34, 2001 相似文献
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用于室温磁制冷机的高场强永磁磁路设计 总被引:1,自引:0,他引:1
把基于磁热效应的室温磁制冷技术应用到空调及家用冰箱上,除了开发出具有巨磁热效应的磁致冷材料(磁工质)外,高场强永磁磁路的设计与制造也是其关键。由于在空调及家用冰箱上采用结构复杂、价钱昂贵的超导磁体或电磁铁是不合适的,而传统永磁体回路的设计方法很难使永磁体产生较高的场强。本文在中空圆柱型磁场源(hollowcylindricalfluxsource)的基础上,设计出了用于室温磁制冷机(往复式和旋转式)的高场强永磁磁路,在磁路工作气隙为20mm时,工作气隙中心的场强分别为1 86T和1 97T。 相似文献
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