高阶多项式在拟合铁磁物质磁滞回线中的应用

探讨用不小于三阶的多项式去拟合磁滞回线,完成只用2个多项式拟合整个回线.区别于其他人提出的实际上是利用二次多项式达到的一条曲线分2段、整个回线分4段的拟合.     

铁磁材料的磁化曲线及磁滞回线

铁磁材料在日常生活及工业制造中应用广泛,尤其在电机、变压器和电感器的制造中,有着不可替代的作用.铁磁质的磁化特性常由磁滞回线、磁化曲线和磁导率曲线来表达,然而所用曲线横纵坐标值的含义却是不一样的,容易产生歧义,给教学、科研和工程设计带来许多困扰.对磁滞回线、磁化曲线和磁导率曲线作对比分析,并嵌入交流量的瞬时值、最大值和...     

铁磁材料磁导率测量实验研究

本文对电磁学实验中用示波器法测量铁磁材料饱和磁导率μmax的问题进行了研究。通过改变励磁电压U和取样电阻R1的阻值后分别测得μ-H关系曲线,对饱和磁导率μmax随R1变化规律进行了深入研究。     

铁磁材料磁化特性实验的数据处理及相关讨论

利用Origin6.0软件处理实验数据,描绘了铁磁材料的基本磁化曲线和磁滞回线.初步讨论矫顽力有没有解析解.     

采用BP神经网络拟合铁磁材料的磁滞回线

介绍了采用BP神经网络模拟人脑智能拟合铁磁材料磁滞回线的方法,给出了实现磁滞回线拟合的BP神经网络结构模型.拟合结果表明,该方法拟合精度较高,对解决非线性拟合问题非常有效.     

霍尔法磁化曲线与磁滞回线实验仪的退磁技巧

针对用HM-1霍尔磁化曲线和磁滞回线实验仪对实验样品铁磁材料退磁过程中退磁难的问题,采用对称退磁法.即在退磁过程中,视铁磁样品中剩磁的方向、剩磁值的多少,加上相应值的反向磁场即矫顽磁力,构成逐渐缩小且最终趋于原点的循环退磁曲线,从而达到给铁磁样品快速退磁的目的,提高了实验教学质量.     

铁磁材料磁化曲线的智能观测系统

利用单片机系统控制物理实验过程，智能地测绘起始磁化曲线和磁滞回线，从而使学生们看到完整的磁化过程，对铁磁物质的磁滞现象有个充分的认识。     

利用Origin8.0软件简化大学物理实验数据的处理

以铁磁材料磁化曲线与磁滞回线实验为例,介绍如何利用Origin8.0软件中绘图、曲线拟合、积分等功能简化对数据进行处理过程。针对处理后数据进行讨论,并将操作方法推广到其他大学物理实验中。     

基于Jiles-Atherton理论的铁磁材料塑性变形磁化模型修正

Jiles-Atherton(J-A)模型在磁化建模领域应用广泛,但不同文献给出的J-A模型并不一致,致使采用不同表达式建立的塑性变形磁化模型存在多种版本,其正确性难以甄别.通过对无磁滞磁化方程、能量守恒方程和等效磁场强度方程的梳理与比较,发现原有模型中存在将磁化强度和无磁滞磁化强度混用、将不可逆磁化能量等效于全部的磁化能量、等效磁场强度中应力磁化项界定不清等问题.在此基础上,对上述方程进行了修正,推导了基于J-A模型的塑性变形磁化修正模型.将修正模型计算结果与原模型计算结果、相关文献中的试验结果进行对比,结果表明:与原有计算模型相比,修正模型计算结果的饱和磁化强度和剩余磁化强度随塑性变形增加而减小,矫顽力随塑性变形增大而增大,达到饱和磁化强度时的外磁场强度随塑性变形增大而增大的趋势有所减弱,更符合试验结果,可更准确地反映塑性变形对材料磁化的影响.     

测量铁磁材料的交流磁化曲线及磁性参量

用数字存储示波器和计算机测量铁磁材料的交流磁化曲线及磁性参量,可以较完整、准确地了解铁磁材料的交流磁特性.     

示波器观测动态磁滞回线实验中曲线描绘浅析

给出了示波器观测铁磁材料物质磁滞回线的基本原理,针对实验中常见的错误,介绍了如何选取合理的数据并快速描绘磁滞回线的技巧。     

用三角波电流励磁改进交流磁滞回线实验简

改进行了交流磁滞回线实验的励磁方法。研制了三角波电流交流恒流源驱动励磁线剖励磁．使软磁环形样品被交流磁化双向交替达到饱和,磁化场H的波形仍为三角波。维持三角波电流的周期和幅值不变．可使H变化的波形和变化的速率不变。可在H匀速变化的条件下观测样舳的交流磁滞回线;能在磁化场相同的条件下观测不同样品的交流磁滞回线;还可直接观测样品的微分磁导率曲线。     

Hysteresis of the Magnetic Particle in a Dipolar Ising Model

Zero-temperature Monte Carlo simulations are used to investigate the hysteresis of a magnetic particle in a dipolar Ising model.The magnetic particle is described in a systemm of permanent dipoles,and the dipoles are located in a cubic lattice site.The effects of the shape and the size of the particle on the hysteresis loop at zero temperature are obtained.For strong exchange interactions,the shapes of magnetic hysteresis loops approach rectangle.For weak exchange interactions,the effects of the size and the shape of the particle on the loops are more remarkable than those of strong exchange interactions case.The slope of the hysteresis loop decreases with the increase of the ratio of the semi major axis to the semi minor axis of the ellipsoidal magnetic particle,and there is an increase of the slope of the hysteresis with the decrease of the size of the magnetic particle.The effects of the shape and size of the particle on the coercive force at zero temperature are also investigated.     

Susceptibility and Inverted Hysteresis Loop of Prussian Blue Analogs with Orthorhombic Structure

The magnetic susceptibility of ternary metal Prussian blue analogues with orthorhombic structure is studied using Ising model. Within the frame work of effective-field theory with correlations, the roles of the mole fraction y, uniaxial magnetic anisotropy, transverse and longitudinal magnetic field are discussed in details. The temperature dependence of the magnetic susceptibility is also investigated. The interesting phenomenon of the inverted magnetic hysteresis loop has been found. The results can help to understand the experimental work of the molecule-based ferriferrimagnet.     

Susceptibility and Inverted Hysteresis Loop of Prussian Blue Analogs with Orthorhombic Structure

The magnetic susceptibility of ternary metal Prussian blue analogues with orthorhombic structure is studied using Ising model. Within the frame work of effective-field theory with correlations, the roles of the mole fraction y, uniaxial magnetic anisotropy, transverse and longitudinal magnetic field are discussed in details. The temperature dependence of the magnetic susceptibility is also investigated. The interesting phenomenon of the inverted magnetic hysteresis loop has been found. The results can help to understand the experimental work of the molecule-based ferri-ferrimagnet.     

基于Matllab的约束最小二乘法拟合磁滞回线

由实验测得的磁滞回线数据的是一系列离散、带噪声的值。通过约束最小二乘方法对曲线进行分段拟合,使曲线的畸变程度得到了改善,准确地表达磁滞回线的特性,为磁材料的定量分析述提供了基础。     

Zero—field—cooled and field—cooled magnetizations and magnetic susceptibility of itinerant ferromagnet SrRuO3

Zero-field-cooled(ZFC) magnetization,field-cooled(FC) magnetization,ac magnetic susceptibility and major hysteresis loops of itinerant ferromagnet SrRuO3 have been measured at magnetic ordering temperatures ranging from 5 to 160K.An empirical model is proposed to calculate the measured ZFC magnetization.The result indicates that the calculated ZFC magnetization compares well with the measured one.Based on the generalized Preisach model.both the ZFC and FC curves are reproduced by numerical simulations.The critical temperature and critical exponents are determined by measuring the ac magnetic susceptibility in different bias magnetic fields at temperatures in the vicinity of the point of phase transition.     

Ferromagnetic materials under high pressure in a diamond-anvil cell:A magnetic study

A magnetic-parameter measurement system for study of ferromagnetic materials under high pressure using a diamondanvil cell is built. The factors affecting the measurement sensitivity are analyzed and the possibility of improving the sensitivity is mentioned. Based on the system, the magnetization curves of iron as a function of pressure are obtained. The start point and end point of pressure-induced magnetic transition of iron are observed at room temperature.     

一维钻石链反铁磁Ising模型磁化的模拟

采用Monte Carlo模拟方法对自旋为1/2的一维钻石链反铁磁Ising系统的磁化行为进行研究.在这个系统中,反铁磁的交换作用和三角结构导致存在自旋阻挫.重点研究不同的反铁磁自旋交换作用对系统磁行为和自旋构型的影响.模拟磁化曲线中M=M_S/3磁化平台,得到平台宽度随不同的自旋交换相互作用强弱的变化关系,以及出现磁化平台时格点的自旋构型;给出亚稳态存在的条件及亚稳态时的微观构型.研究磁滞回线随温度的变化关系.结果表明,随着温度的升高,磁滞回线逐渐减小,最终消失.