非线性磁化特性对物体磁性处理过程的影响

在瑞利磁化区中建立了剩余磁化强度随外磁场变化的数学物理模型；研究了在用等比例衰减振幅的工作磁场对物体作用时，物体剩余磁化强度与工作磁场衰减比例常数间的数学关系；讨论了物质非线性磁化特性和磁滞特性对综合消磁过程中工作磁场的要求；在一定程度上说明了不同的消磁标准对比例常数的限制。     

预应力条件下超磁致伸缩材料的温度敏感性分析

超磁滞伸缩材料Terfenol-D具有应力温度敏感特性,通过循环油浴加热的实验方法,测量超磁致伸缩材料在力热磁耦合下的磁滞回线,发现预应力的增加有效降低了温度对材料低磁场性能的影响,材料显示出了良好的低磁场下的温度稳定性能.试件在高应力120 MPa,在磁场300 kA/m下的磁化强度出现了先增大后减小的现象,磁化衰减幅度得到减弱.     

钢管整体关联消磁技术

在钢管无损检测中 ,常常利用钢管的磁异常现象进行缺陷检测。检测前 ,首先对钢管磁化 ,然后再进行检测 ,但是 ,磁化后的钢管会有剩磁 ,这种剩磁不但给后继加工 (如螺纹加工、焊接 )、安装及使用造成不便 ,也会影响仪器设备的正常工作 ,所以 ,检测后的钢管必须进行消磁处理。常规消磁技术效果差 ,不能满足实际需要 ,故提出一种新的消磁技术 ,即整体关联消磁技术 ,该技术把消磁与磁化统一起来 ,利用磁体的特性与磁感应强度的矢量特性进行消磁 ,实际使用证明 ,该技术设备简单、功耗低 ,消磁效果好     

漏磁检测中的磁化技术

在磁性无损检测中,磁化是实现检测的先决条件,它决定着被测对象能否产生出可被测量和可被分辨的磁场信号,同时也影响着检测信号的性能特性和检测装置的结构特性。因此,针对被测构件结构特点和测量目的,选择磁化方式和磁化强度是磁化的关键。     

智能控制高速复合消磁方法

文章研究一种智能控制高速复合消磁方法,通过磁敏传感器阵列自动检测各种口径铁磁质工业管件的表面剩余磁场的强度、极性和节距,为DSP信号处理器提供数据,DSP控制消磁参数,驱动复合消磁器对铁磁管件进行高速和可靠的消磁。开发的智能控制高速复合消磁设备能可靠消除各种口径铁磁质工业管件的剩余磁场,解除后续加工、安装和使用中遇到的剩磁困扰。     

由转矩测量磁性的一种特殊方法

将磁场偏开易磁化方向４５°角，测量在两个不同磁场强度时的转矩大小，通过计算得到磁性薄膜或颗粒的磁化强度和磁各向异性常数的数值．它不需要测量出转矩曲线，也不一定需要很高的磁场，使测量过程简单而方便．     

铁磁基体上覆盖层磁化分布

研究铁磁体表面上形成的覆盖层的磁化分布,得到了垂直磁化或平行磁化时铁磁体内磁化强度、覆盖层内各向异性常数和层与基体间交换常数满足的关系     

铁磁基体处覆盖层磁化分布

研究铁磁体表面上形成的覆盖层的磁化分布，得到了垂直磁化或平行磁化时铁磁体内磁化强度、覆盖层内各向异性常数和层与基体间交换常数满足的关系。     

舰船周围铁磁物体对其磁场的影响

舰船与周围铁磁物体相互磁化产生附加的感应磁场,影响舰船磁场的磁感应强度的测量,针对此问题提出一种求解附加感应磁场的磁感应强度的计算方法。该方法以舰船与铁磁物体的磁偶极子阵列作为磁场数学模型,以系数矩阵条件数为目标函数的蚁群算法来优化磁偶极子的分布位置,并把物体的磁化等效为其磁模型中各磁偶极子的磁化,借助于均匀地磁场对舰船、铁磁物体磁化产生的感应磁场的磁感应强度来求解出各自的附加感应磁场强度,最终得到舰船磁场的磁感应强度。实验结果表明:该计算方法可行,且计算精度较高。     

带状铁磁非晶体金属的磁化和磁致伸缩特性

用推广了的模型，讨论带状铁磁非晶体金属在弱磁场中的磁化和磁致伸缩特性。导出磁化强度和磁致伸缩作为磁场函数的解析式。磁场小于各向异性场的一半时，得出两个解。把此二解对各向异性轴分布求平衡并应用于三个简单模型，得出一些有意义的结果。     

磁化预处理作用下光催化降解水中有机染料

将磁化与光催化结合对酸性红B溶液进行降解．结果表明,磁化可以提高酸性红B溶液对紫外光的吸收;影响光催化过程．通过合理实验设计,研究了磁化时间、磁场强度对光催化的影响,讨论了磁化对光催化过程的作用机理,提出磁化对光催化存在协同作用．     

Fe纳米线阵列宏观磁性的Preisach模拟

采用阳极氧化铝模板法制备16nm的铁纳米线阵列膜,并研究了其宏观磁学性质.沿着纳米线长轴加场测得的磁滞回线表现出高的矫顽力和矩形比,归因于垂直于膜面的高形状各向异性.等温剩磁曲线和直流退磁曲线的测量结果表明纳米线阵列体系中存在强烈的退磁性相互作用.采用Preisach模型对相关曲线进行模拟,发现剩磁矫顽力和相互作用场的分布较窄,是一种典型的符合双势垒模型的体系.     

铁钴合金纳米线有序阵列的制备及其磁性表征

用电化学法制备了高度有序的多孔阳极氧化铝（AAO）模板，选摩尔比为1：1的CoSO4和FeSO4混合溶液为电解液，用交流电化学沉积法在多孔阳极氧化铝的柱形微孔内制备Fe0.5 Co0.5合金磁性纳米线有序阵列．分别用扫描电镜、透射电镜、X射线衍射仪对多孔氧化铝模板和纳米线阵列的微观形貌和结构进行分析，用振动样品磁强计（VSM）对样品的磁学性能进行测试．结果显示，制备的磁性合金纳米线表面光滑、均匀，纳米线中的晶粒在生长过程中有（200）晶面的择优取向．VSM测试结果表明，纳米线阵列结构具有较高的垂直磁各向异性，当外场沿纳米线轴向磁化时，纳米线阵列有很大的剩磁比（Mr／Ms=0．7）和很大的矫顽力（饱和Hc=1700 Oe），说明样品经适当热处理后，剩磁比和纵向矫顽力普遍得到提高．     

铁磁材料动态磁性的计算机辅助测量与研究

利用微机辅助测量技术来研究磁滞回线的动态磁化过程 ,分析在不同的初始磁场强度下的磁滞回线 ,并从理论上进行了深入的讨论 .     

R3Co11B4中的磁作用

用两格点分子场理论分析了钴基合金R3Co11B4(R=Pr,Nd,Tb,Dy)的自发磁化随温度变化的关系,采用数值拟合的方法计算出了描述3种磁作用的分子场系数n(RR),n(RCo)和n(CoCo),得到了居里温度,给出了交换场强度随温度变化的曲线.     

Frequency dependence of magnetization and giant magneto impedance effect of amorphous wires

The frequency dependence of magnetization process and giant magneto impedance (GMI) effect of Co-rich melt-extracted amorphous wires was studied by Kerr effect and impedance analyzer, respectively. It is demonstrated that the transverse Kerr intensity and the corresponding GMI response increase with increasing frequency, which contributes to the upgraded skin effect. However, the skin depth has a slothful trend with frequency when it is up to the megahertz range, which gives rise to the transformation of magnetization. The process is much more sensitive to the direct current magnetic field and the sensitive change of the circular permeability, and GMI response is observed as its consequence. This proves that the evolution of circumferential magnetization and the corresponding permeability with the direct current magnetic field is the essence of GMI response, and a much more sensitive magnetization promises a better GMI response.     

磁化率对大地电磁响应影响异常规律研究

为探究地下介质的磁化率性质对大地电磁观测数据的影响,本文在常规大地电磁的正演过程中引入磁化率这一物性参数,利用有限单元法实现了同时考虑电阻率和磁化率的二维大地电磁正演算法。通过建立不同模型进行正演计算,详细分析了磁性体的磁化率值、背景电阻率值、埋深等参数对大地电磁正演结果的影响,总结出两种判定地下磁性体是否会对大地电磁数据产生影响的方法：若已知地下磁性体的规模,可根据磁性体的埋深与边长的比值系数判定;若未知地下磁性体的规模,可根据地磁测资料磁异常的幅值变化判定。     

变压器铁心电磁振动仿真及影响因素研究

为了研究变压器铁心的电磁振动的多场耦合问题,使用应变能原理修正铁心磁-结构耦合关系对变压器铁心的本体振动进行仿真研究.将硅钢片磁化特性曲线导入到仿真模型中,计算得到线圈中的电流密度以及铁心闭合回路中的磁感应强度分布,实现电场与磁场的耦合.利用应变能原理对磁致伸缩力进行等效,并以等效磁致伸缩力为耦合变量对铁心进行结构瞬态动力分析,得到铁心本体的振动分布.分析铁心电磁振动的影响因素,结果表明:随着铁心预紧应力增大,硅钢片磁致伸缩增量比值增大,铁心振动加剧;随着铁心叠片方向上的弹性模量增大,铁心振动量逐渐降低.仿真结果定性地验证了装配工艺对铁心振动的影响规律.     

Magnetoresistive behavior and magnetization reversal of NiFe/Cu/CoFe/IrMn spin valve GMRs in nanoscale

The magnetoresistance behavior and the magnetization reversal mode of NiFe/Cu/CoFe/IrMn spin valve giant magnetoresistance (SV-GMR) in nanoscale were investigated experimentally and theoretically by nanosized magnetic simulation methods. Based on the Landau-Lifshitz-Gilbert equation, a model with a special gridding was proposed to calculate the giant magnetoresistance ratio (MR) and investigate the magnetization reversal mode. The relationship between MR and the external magnetic field was obtained and analyzed. Studies into the variation of the magnetization distribution reveal that the magnetization reversal mode, that is, the jump variation mode for NiFe/Cu/CoFe/IrMn, depends greatly on the antiferromagnetic coupling behavior between the pinned layer and the antiferromagnetic layer. It is also found that the switching field is almost linear with the exchange coefficient.     

Novel Plastic Encapsulation Holding Method for Automobile Glass Using Injection Molding Process

Glass positioning and holding is difficult in the process of injection molding encapsulation of automobile glass. A suction cup or soft resin is always introduced in this process. However, these materials cannot hold glass tightly, thus resulting in the unsteady quality of toughened glass and encapsulated plastic. To solve this problem, a novel holding method called magnetic high-pressure holding with twin bags is proposed to address the features of toughened glass and the encapsulation injection process. Firstly, a pair of permanent magnets is introduced as energy source, followed by the magnetization of a couple of magnetic particle bags. Contact between the single bag and the glass surface will enable the couple of magnetic particle bags to hold glass tightly and to self-adapt the freeform of the glass. Secondly, an experimental system with mechanical and control systems is designed. This system is controlled by the opening and closing force of the mold, which turns the magnetic field on or off to hold or loosen the glass. The magnetic field distributions are measured at important positions of the permanent magnets and in the magnetized particles in the experiments to determine the holding performance. Finally, the process of determining the parameters of the magnet and its attenuation is analyzed, including the minimum friction force between the glass and the particle bag during injection molding, the magnetic energy product and the magnetized filed distributions, and the re-checklng method for these parameters. The theoretical analysis and the experimental result show that this flexible holding system may produce sufficient holding force, which not only protects glass but serf-adapts the glass freeform as well. The production practice meets the technical requirements of injection molding with a defect-free surface, with no scratches and cracks on the glass and no slight glass movements in the mold cavity.