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本文在电磁感应法的基础上,通过与亥姆霍兹线圈串联使电容达到谐振的改进方法,测量了不同电容参数下的亥姆霍兹线圈磁场分布,并利用Origin软件拟合分析了亥姆霍兹线圈磁场与中心轴线位置的关系.实验结果表明,基于电磁感应的改进方法测得的亥姆霍兹线圈磁场精确度在一定程度上均大于传统电磁感应法的测量结果,3种电容选择中,串联电容为0.099×10-6F时,精确度最高,拟合的亥姆霍兹线圈磁场与中心轴线位置的关系式与理论状态下的公式基本吻合.改进方法的实验效果明显,精确度高,科学可行,是一种值得推广的测量亥姆霍兹线圈磁场的改进方法. 相似文献
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利用DH4501D实验仪探究了亥姆霍兹线圈轴线上和轴线外的磁场分布问题.首先通过对单个线圈不同电流下的磁场分布的实验值与理论值对比发现电流大的磁场更接近理论值,更适合用来研究磁场分布问题.然后利用较大电流分别研究了单个线圈以及亥姆霍兹线圈轴线上和轴线外的磁场分布的规律及产生原因.最后利用磁场分布拟合了真空磁导率并与理论... 相似文献
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亥姆霍兹线圈磁场的均匀性分析 总被引:28,自引:8,他引:20
引入磁场均匀度的概念,对亥姆霍兹线圈磁场的均匀性进行了定量分析,并通过计算机模拟,得出了同一精度下,形成亥姆霍兹线圈均匀磁场的最佳条件. 相似文献
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一类二维时变磁场激发涡旋电场的静电场类比计算 总被引:1,自引:1,他引:0
通过二维涡旋电场与二维静电场分布的比较,求解椭圆柱区域磁场随时间变化所激励的涡旋电场的场强转变为求解电场的势,从而使问题简化。 相似文献
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本文认为在感生电场的情况下,磁场的强弱变化可以引起磁场自身的横向运动,使得线圈中电子相对于磁场发生运动,从而等效为一个动生电场,受到洛伦兹力的作用.借助磁感线模拟磁场的运动方式,得到圆形回路中任意一点与磁场相对运动速度的表达式,进而推得该"等效动生电场"中的洛伦兹力.以螺线管为例,验证该方法可以解释感生电场所满足的规律.将感生电场与动生电场的产生原因统一为导体中电子与磁场的相对运动,相应电动势的非静电力统一为洛伦兹力. 相似文献
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感生电场的计算在大学物理教科书中,一般都是以具有轴对称性磁场变化为特例.在那里,感生电场的方向是不证自明的,真的是这样吗?本文力图说明,对称性并不能取代方向性的说明,方向性问题严格说来需要解边值条件下的微分方程,但在大学物理教学层面上可以有简单的办法处理. 相似文献
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介绍一种计算感生电场的数值方法,它既可用于计算柱形分布均匀变化磁场所产生的感生电场,也可计算分布在任意界面上的变化磁场所产生的感生电场,并给出了一些计算实例. 相似文献
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We examine whether a charge supported statically in a gravitational field radiates, and find the answer to this question to be positive. Based on our earlier results we find that the important condition for the creation of radiation is the existence of a relative acceleration between the charge and its electric field, where such an acceleration causes the curving of the electric field and the creation of a stress force due to this curvature. This stress force is the reaction force, which creates the radiation. Later we find that this condition do exist for a charge supported statically in a gravitational field, where the electric field of the charge falls in the gravitational field, it curves, and the stress force raised in this curved field, creates electromagnetic radiation. 相似文献
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《Journal of Electrostatics》2014,72(5):387-395
In this work, analysis of the human body exposed to high voltage electric and magnetic fields is presented. The distribution of the electric field is obtained by using Laplace's equation. This relates the surface charge induced on the body to the potential in a reciprocal Laplace problem, which is then calculated by charge simulation method coupled with genetic algorithms to determine the appropriate arrangement of simulating charges inside the human body. The magnetic field intensity along the vertical center line of the human is calculated. Exposure to external electric and magnetic fields at power frequency induces electric field, magnetic field and currents inside the human body. The presented model for simulating electric and magnetic fields are a three dimensional field problem and introduced different types of charges to simulate the different elementary geometrical shapes of human body. The particular strength of the charge simulation method in this application is its ability to allow a detailed representation of the shape and posture of the human body. The results have been assessed through comparison induced current, electric field, magnetic field and there distribution over the body surface, as estimated in other experimental and computational work. 相似文献
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Interband luminescence in a parabolic quantum well is studied in applied electric and magnetic fields. It is shown that the luminescence peak is displaced towards higher frequencies with increasing magnetic field strength, while an increase in the electric field strength causes a displacement of the emission peak towards the long-wave region and a decrease in its amplitude. The theoretical results are compared with the experimental data. The existence of a new electromagnetic-wave emission channel (electrically induced luminescence) associated with indirect optical transitions is predicted. The frequency dependence of the electrically induced radiation is computed, taking into account the interaction of an electron with acoustic and optical phonons. It is found that the half-width of the luminescence peak increases with the electric field strength. 相似文献
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We present electronic and optical properties of the hydrogen terminated gallium arsenide nanoparticles using time dependent density functional theory (TD-DFT). The electronic and optical properties of the GaAs nanoparticles were calculated at presence of the uniform external electric field in the range from 0 to 0.51 V/Å. The induced electric filed can decrease the HOMO–LUMO gap of the nanoparticles and the mount of these reductions increases with gain of the electric field strength. 相似文献