Research on electromagnetic relay's dynamic characteristics disturbed by uniform static magnetic field

Electromagnetic relay is a widely used apparatus which usually works in a magnetic disturbance environment. To evaluate its electromagnetic compatibility (EMC) in a static magnetic field, dynamic characteristics of a clapper relay in a uniform static magnetic field situation based on the finite element method (FEM) is studied. Influences of the magnetic field on dynamic parameters (delay time, pick-up time, end pressure, and final velocity) as well as a situation in which the relay cannot function normally are analyzed. Simulation reveals that the external magnetic field which weakens the relay’s air-gap field has a greater influence on the relay’s dynamic parameters than the one strengthening the field. The validity of the simulation is verified by measured results of coil current and armature displacement.

Static and 50 Hz Electromagnetic Fields Effects on Human Neuronal-Like Cells Vibration Bands in the Mid-Infrared Region

Human neuronal-like cells were exposed to static and 50 Hz electromagnetic fields at the intensities of 2 mT and 1 mT, respectively. The effects of exposure were investigated in the mid-infrared region by means of Fourier self deconvolu-tion spectroscopic analysis. After exposure of 3 hours to static and 50 Hz electromagnetic fields, the vibration bands of CH2 methilene group increased significantly after both exposures, suggesting a relative increase of lipid related to conformational changes in the cell membrane due to electromagnetic fields. In addition, PO2- stretching phosphate bands decreased after both exposures, suggesting that alteration in DNA/RNA can be occurred. In particular, exposure of 3 hours to 50 Hz electromagnetic fields produced significant increases in β-sheet contents in amide I, and around the 1740 cm?1 band assigned to non-hydrogen-bonded ester carbonyl stretching mode, that can be related to unfolding processes of proteins structure and cells death. Further exposure up to 18 hours to static magnetic field produced an increase in β-sheet contents as to α-helix components of amide I region, as well.

A Second-Order Eigen Theory for Static Electromagnetic Fields

The static electromagnetic fields are studied here based on the standard spaces of the physical presentation, and the modal equations of static electromagnetic fields for anisotropic media are deduced. By introducing a set of new potential functions of order 2, several novel theoretical results were obtained: The classical potential functions of order 1 can be expressed by the new potential functions of order 2, the electric or magnetic potentials are scalar for isotropic media, and vector for anisotropic media. The amplitude and direction of the vector potentials are related to the anisotropic subspaces. Based on these results, we discuss the laws of static electromagnetic fields for anisotropic media.

An eigen theory of static electromagnetic field for anisotropic media

Static electromagnetic fields are studied based on standard spaces of the physical presentation, and the modal equations of static electromagnetic fields for anisotropic media are derived. By introducing a new set of first-order potential functions, several novel theoretical results are obtained. It is found that, for isotropic media, electric or magnetic potentials are scalar; while for anisotropic media, they are vectors. Magnitude and direction of the vector potentials are related to the anisotropic subspaces. Based on these results, we discuss the laws of static electromagnetic fields for anisotropic media.

Direct Generation of Intense Compression Waves in Molten Metals by Using a High Static Magnetic Field and Their Application

Compression waves propagating through molten metals are contributed to degassing, accelerating reaction rate,removing exclusions from molten metals and refining solidification structures during metallurgical processing of materials. In the present study, two electromagnetic methods are proposed to generate intense compression wavesdirectly in liquid metals. One is the simultaneous imposition of a high frequency electrical current field and a staticmagnetic field; the other is that of a high frequency magnetic field and a static magnetic field. A mathematical modelbased on compressible fluid dynamics and electromagnetic fields theory has been developed to derive pressure distributions of the generated waves in a metal. It shows that the intensity of compression waves is proportional to thatof the high frequency electromagnetic force. And the frequency is the same as that of the imposed electromagneticforce. On the basis of theoretical analyses, pressure change in liquid gallium was examined by a pressure transducerunder various conditions. The observed results approximately agreed with the predictions derived from the theoreticalanalyses and calculations. Moreover, the effect of the generated waves on improvement of solidification structureswas also examined. It shows that the generated compression waves can refine solidification structures when they wereapplied to solidification process of Sn-Pb alloy. This study indicates a new method to generate compression wavesby imposing high frequency electromagnetic force locally on molten metals and this kind of compression waves canprobably overcome the difficulties when waves are excited by mechanical vibration in high temperature environments.

Research Progress on Slag Resistance of Refractories with Electromagnetic Field

As the essential material for high temperature industrial production and technological development such as metallurgy,refractory has an important influence on the safety and efficiency of production for high-quality steels.Slag corrosion is one of the main reasons causing the wear of refractories.The slag resistance of refractories can be enhanced by regulation and control of the composition and structure,while applying the external electromagnetic field can achieve the good performance.Electromagnetic field can not only change the thermo physical properties of slags,but also have a significant effect on the slag resistance of refractories.Suitable electric field can slow down the slag corrosion while the influence of conductivity of refractories is obvious;The magnetic field with millitesla level have a significant impact on the high temperature properties of the slags,and the alternating magnetic field can accelerate the slag corrosion of the refractories,while the static magnetic field has a promising potential to improve the slag resistance of the refractories.Furthermore,the interaction mechanism between refractories and slags under magnetic field needs to be clarified in order to develop the magnetic resistance against slag corrosion of refractories.

Cellular Psychology Assumption: Based upon Exterior Algebra, It Contributes to Explaining the Variability of the Bioeffects of Magnetic and Electromagnetic Fields

According to its own purposes, including survival, the cell reacts to the conditions of its medium. Such a vital phenomenon implies relational energetics. It includes unconscious psychic energy whose regulating model is the Life and Sense archetype. Its relational power could result from a natural algebraic property of extension. This extension can extend any organic magnitude to 4D event. Thus it allows some perception of the extracellular structure variations. This perception applies to moving forces of the cell signaling activators, through psychic energy. This psychical energy includes a potential, the cell attitude or status, and psychic moving forces, or tendencies. Insofar as the psychic potential is sensitive to proton structures, and the psychic moving forces are excitable by electron exchanges, a phase shift between us may occur. Medium stimulation by adequate magnetic fields could modulate this phase shift in a therapeutic direction.

Cellular Perception: When the Cell Model Includes a Sense Order which Ensues from a Philosophy of Nature, the Signaling and Epigenetics Effects which Can Result from Exposure to Magnetic Fields Are Described Better

Academic biology-medicine refers to a couple of philosophies, Organicism and Mechanism, which translates into an association of Cybernetic diagrams and molecular Reductionism. This association presents logical difficulties which make it unsuitable to describe correctly biological effects of electromagnetic fields, EMF. But these logical difficulties may be overcome when renewing the organic cell idea by means of a Philosophy of Nature which juxtaposes causality order and sense order in the cell. The signalsome, the set of descriptive components resulting from the genome, is constantly reorganized. This remodeling may become epigenetic when the phenotype becomes transformed by experience of perceptions in a given medium, because the perception of overall information coming from the extracellular medium becomes functional within the system. In that cellular perception, it is stated that the significance base which contributes to the sense order results from the qualitative topological structure of the extracellular medium. Therefore the EMF interactions target is not only the membrane and its molecules;it is also the structure of the extracellular medium which bathes the membrane. Knowing that the sense order modulation constitutes the global soil of the (localized) causality order, it is possible to obtain a same EMF bioeffect on a membrane molecule by treating a culture of cells in its bath or by treating only the extracellular aqueous medium. Consequently, the double bioeffect resulting from EMF exposure is described simply, because the sense order, such as it results from the qualitative structuring of the medium, forms the significance base which directs the causal mechanics of the cellular answer.

Numerical Simulation of Level Magnetic Field

According to Maxwell electromagnetic field theory and magnetic vector potential integral equation,a mathematical model of LMF(Level Magnetic Field)for EMBR(Electromagnetic brake)was proposed,and the reliable software for LMF calculation was developed.The distribution of magnetic flux density given by numerical simulation shows that the magnetic flux density is greater in the magnet and magnetic leakage is observed in the gap.The magnetic flux density is uniform in horizontal plane and a peak is observed in vertical plane.Furthermore,the effects of electromagnetic and structural parameters on magnetic flux density were discussed.The relationship between magnetic flux,electromagnetic parameters and structural parameters is obtained by dimensional analysis,simulation experiment and least square method.

Experiment on low-frequency electromagnetic waves propagating in shock-tube-generated magnetized cylindrical enveloping plasma

We propose a method of applying a static magnetic field to reduce the attenuation of the magnetic field component(SH) of low-frequency electromagnetic(LF EM) waves in dense plasma. The principle of this method is to apply a static magnetic field to limit electron movement, thereby increasing the equivalent resistance and thus reducing the induced current and SH. We consider the static magnetic field acting on the plasma of the entire induced current loop rather than on the local plasma, where the induced current is excited by the magnetic field component of LF EM waves. Analytical expressions of SH suitable for magnetized cylindrical enveloping plasma are derived by adopting an equivalent circuit approach, by which SHis calculated with respect to various plasma parameter settings. The results show that SH can be reduced under a static magnetic field and the maximum magnetic field strength that mitigates blackout is less than 0.1 T. Experiments in which LF EM waves propagate in a shock-tubegenerated magnetized cylindrical enveloping plasma are also conducted. SH measured under the magnetic field(the magnetic field strength B0 acting on the magnetic field probe was about0.06 T) reduces at f=10 MHz and f=30 MHz when ne≈1.9×1013 cm-3, which is consistent with theoretical results. The verification of the theory thus suggests that applying a static magnetic field with a weak magnetic field has the potential to improve the transmission capacity of LF EM waves in dense plasma.

水下磁传感器定位定姿数值验证实验研究

[目的]旨在构建一种水下磁传感器校准装置设计方案。该装置由电磁线圈和组合导航设备构成,能够搭载水上机动平台在水面航行,实现水下磁传感器位置和姿态的高精度校准。[方法]根据电磁线圈的姿态方位信息及其在水下磁传感器处产生磁场的测量值,采用非线性最优化算法计算水下磁传感器的位置和姿态,并建立全系统的数学模型进行数值验证实验,将电磁线圈的方位和姿态测量精度、磁传感器的噪声和测量误差以及地磁场干扰的影响纳入考虑。[结果]实验结果表明,磁传感器在水下30 m深度时,装置的定位误差均值不大于0.06 m,姿态误差均值不大于0.20°。磁传感器自身精度是影响校准精度的主要因素。[结论]校准装置能够同时实现水下磁传感器位置和姿态的高精度校准,具有较高应用价值,可广泛用于水下磁性目标探测、资源勘探、医学等领域,尤其适用于姿态发生偏移的水下磁传感器校准。

“电磁场”课程体系和教学内容的改革与实践

阐述了似稳场与准静态场概念上的差异,针对电气工程与电子信息类专业普遍是在大学物理“电磁学”课程之后开设“电磁场”课程的现状,提出减少“电磁场”与“电磁学”在教学内容上的重复,在教材和教学上简化纯粹静态场内容,突出对准静态电场、磁场概念的讲解,并在准静态场的范畴中引入标量电位和矢量磁位、标量磁位以及电阻、电容与电感参数,以提高学生理解和解决实际工程问题的能力。

磁场对间充质干细胞成骨的生物学效应

背景:间充质干细胞具有自我复制和多向分化潜能,在骨组织再生领域备受关注。磁场作为非侵入性的物理刺激因素能够有效调控间充质干细胞的黏附、增殖、成骨向分化和矿化等生物学行为,在骨组织再生医学领域具有广泛的应用前景。磁场的效应取决于磁场强度、频率和暴露时间等参数。由于窗口效应,磁场促进骨再生的适宜参数范围仍有待明确。目的:回顾不同类型磁场和不同磁场参数对间充质干细胞成骨分化的影响及可能机制,并归纳总结促增殖和成骨向分化的适宜参数范围。方法:以“magnetic field,static magnetic field,pulsed electromagnetic field,mesenchymal stem cells,proliferation,osteogenic differentiation,bone regeneration,bone repair”为英文检索词,以“磁场,静磁场,脉冲电磁场,间充质干细胞,增殖,成骨分化,骨再生”为中文检索词,分别检索PubMed数据库和中国知网,主要检索时间范围为2010年1月至2021年9月,同时纳入少量远期经典文献。通过文题及摘要进行初筛,排除重复性、低相关性和低价值的研究,最终纳入56篇文献进行综述。结果与结论:(1)中等强度静磁场、低频或低强度脉冲电磁场促进间充质干细胞增殖和成骨向分化的效果良好,而高频脉冲电磁场产生明显的抑制作用;(2)磁场调控效果与总暴露时间呈正相关,但其效应并不随单次间歇暴露的时间延长而增加;(3)干细胞类型、分化阶段和细胞密度等磁场外因素对磁场的生物学效应也具有复杂的影响,临床上应给予关注;(4)磁场对质膜、细胞骨架和离子通道等细胞靶点产生作用,作用机制主要包括磁机械相互作用、电动力相互作用和自由基对效应。

农业生物的电磁环境效应研究综述

大量的实验证明静电场、静磁场和交变电磁场作用于农业生物体会产生各种各样的生物学效应，其中促进生物生长发育的效应称为正效应或兴奋效应，阻碍或破坏生物生长发育的效应称为负效应或抑制效应。该文总结了近年来国内外有关农业生物电磁环境效应研究的主要内容，及其在农业工程领域中的应用情况；指出了农业生物电磁环境效应的主要特点，并提出了对该领域进一步研究的几点建议。

磁声波对金属凝固组织的影响

提出了运用强磁场和交流电流的共同作用直接在金属液中产生声波（磁声波）的新方法,并研究了所生成的磁声波在细化合金凝固组织晶粒的效果.该方法可以从根本上解决机械声波无法在高温生产领域应用的难题.理论解析表明,运用交变电磁力在液体金属内生成的磁声波的强度和所施加的静磁场的磁感应强度和交流电流的电流密度的乘积成正比;电磁力的频率越大,生成的磁声波越接近于由机械振动产生的声波.实验中测定的磁声波压力和理论解析结果基本一致.这种方法产生的磁声波具有促进金属凝固组织晶粒细化的作用.

电偶源频率电磁测深中的E_x分量

在电偶源频率电磁测深（包括ＣＳＡＭＴ）的各场量中，电场Ｅｘ分量具有分辨率高、观测信噪比高、不需作近场改正等优点。在有地表电性不均匀引起的静态偏移情况下，可通过转换相位消除静态偏移。因此在资料处理与解释中可不局限于比值电阻率的模式，使频率电磁测深具有更大的灵活性与适应性。

静态和极低频电磁场非热生物效应的研究动态

人为电磁场对人类健康可能的影响尤其是电磁辐射与肿瘤发生的关系,日益引起人们的关注,电磁场的生物学效应得到全世界的广泛研究。我们着重介绍近5年来关于静态磁场和极低频电磁场生物效应的研究进展,包括信号转导、基因表达、染色体畸变、基因突变等细胞学和分子水平研究,以及致癌风险和健康危害评价等内容,并对该领域的未来研究进行了探讨。

静磁场在材料生产过程中的应用研究评述

在材料电磁过程研究中 ,静磁场尤其是强磁场材料科学是当今世界的研究热点。本文从静磁场作用下生成的洛仑兹力和磁化力两个角度系统地归纳总结了静磁场技术在材料生产领域的应用原理和实践。对静磁场下的洛仑兹力 ,主要介绍了流体流动、波动和对流控制、电磁振动及电磁超声波等方面的研究现状 ;对强磁场下的磁化力 ,主要介绍了其在相变、结晶配向、磁悬浮、磁对流等方面的研究进展。

电子回旋共振推力器中和器内磁场与微波电磁场计算分析

电子回旋共振推力器具有寿命长、比冲高、结构简单等特点,用于深空探测主推进具有很大的吸引力。中和器是电子回旋共振推力器的关键部件之一,其主要作用为产生电子,中和离子源发射的离子束流,它对保持电子回旋共振推力器的电位平衡有着重要作用。文中针对10 cm推力器的中和器,采用ANSYS有限元分析软件建立了磁路模型,计算了中和器内磁场分布,得出了方案中电子回旋共振面的位置。针对中和器的工作特点,设计了多种天线方案,利用ANSYS软件计算了其对应的电磁场分布。计算结果表明,设计磁场提供的电子回旋共振面位置合理,L型天线方案可实现放电击穿,产生等离子体。计算结果对电子回旋共振推力器的中和器设计与研制提供了帮助。

高频电磁水处理器处理腔的电磁场仿真分析及实验

处理腔是高频电磁水处理器的重要组成部件,为了确定何种处理腔结构对高频电磁阻垢除垢具有更佳的效果,利用准静态学方法对2种常见的处理腔即同轴式处理腔和螺线管式处理腔进行了电磁场分析,得到了同轴式处理腔主导场为电场、螺线管式处理腔主导场为磁场的结论;利用Ansoft Maxwell软件建立了有限元模型,仿真分析其内部的电磁场能量的分布,仿真分析表明:当施加相同的激励源并处理相同体积的水时,同轴式处理腔内的电磁能量大于螺线管式处理腔;最后,设计了一套高频电磁阻垢除垢系统和微型循环水系统,并自行配兑钙离子浓度为5mmol/L的碳酸钙溶液进行了实验研究,检测了溶液中电导率和生成的晶体形态,并用挂片法测定了阻垢率。实验结果表明:2种处理腔都有一定的阻垢效果,但同轴式处理腔的阻垢效果明显优于螺线管式处理腔。