磁流变制动器电磁装置的理论分析与计算

电磁装置是磁流变制动器中的一个十分重要的组成部分,由其形成可控的电磁场,可以使磁流变材料产生相应的制动力矩,从而控制制动器的制动性能.本文通过对电磁装置进行理论分析,对电磁装置中各参数进行选择,并通过LABVIEW软件编程,对各参数进行计算,得出优选的参数值,为进一步对电磁装置进行结构设计和控制提供理论依据和重要的数据.     

电磁防护仿生技术研究的进展与展望

为了从生物中汲取灵感,进而设计抗干扰能力强、可靠性高的电子系统,对近些年新兴的电磁防护仿生技术的发展脉络进行了详细总结.阐述了电磁防护仿生技术主要研究内容,并展示了现阶段电磁防护仿生研究已取得的成果.生物的神经系统是高度复杂的信息处理和控制系统,具有自组织和自适应的优良特性,同时也具有很高的容错能力.因此,结合神经信息处理方式、编码特点和集成电路实现,进一步探讨和分析了进行电磁防护仿生研究的新思路.     

磁力耦合机电产品电磁-结构多场联合仿真方法研究

针对磁力耦合机电产品分析和计算仅局限于单一场,无法充分反映产品电磁-结构耦合工作特性的问题,提出了一种电磁-结构多场联合仿真方法。基于结构动力学方程和麦克斯韦电磁场方程分析了激活装置输出电压,通过电磁仿真获取磁力参数,结合Adams动力学模型开展电磁-结构多场联合仿真。通过激活装置磁力矩和输出电压测试,结果表明,电磁-结构联合仿真方法计算误差可控制在5%以内。本文提出的电磁-结构联合仿真方法可提高磁力耦合机电产品计算精度,对磁力耦合机电产品性能研究具有参考价值。     

压应力下铁镓合金动态磁滞曲线的测试与分析

铁镓合金的磁滞特性和电磁损耗是材料应用的基础。基于安培定律和法拉第电磁感应定律设计了一套简易的测试装置,运用该装置准确地测试了铁镓合金棒在不同磁场频率和压应力下的磁滞曲线,分析了矫顽力和电磁损耗的变化情况。结果表明,铁镓合金棒在恒定的压应力作用下,随着磁场频率的增加,磁滞曲线面积增大,矫顽力和电磁损耗增大,铁镓合金棒在恒定的磁场频率下,随着压应力增大,磁滞曲线面积减小,矫顽力和电磁损耗增大。     

CRT电磁泄漏机理分析与接收装置的设计

在分析CRT电磁泄露的机理、深入研究电子加速场和CRT辐射源在信息泄露中的特点基础上,设计了一种接收装置,使微弱、高频电磁信号重现成为可能。     

基于仿生概念的网电空域鲁棒性研究

阐述了网电空域研究工作中以仿生方式进行电磁防护研究的基本内容,对研究内容在整个仿生领域中予以定位。定义了网电空域的基本概念,分析了空间电磁环境的安全问题,建立了电磁防护仿生研究的表象级对等模型,提出并归纳了研究策略和实现基础。根据结构和功能的关系进行相应方案的规划,并结合生物鲁棒性的研究成果,在分级冗余基础上考虑鲁棒裕度设计,描述网络简并、功能梯度和旁路易化的特征。因此,使得网电环境下电磁防护的仿生构想在技术上成为可能。     

惯性导航系统显示控制装置的电磁兼容性分析与设计

以惯性导航系统显示控制装置为研究对象，分析了它的电磁兼容性。归纳出它的主要干扰源、电磁耦合途径、敏感器件，结合电磁兼容的基本原理并有针对性的采取了改进措施。测试结果表明电磁干扰有效地被抑制了，使显示控制装置通过了国家标准电磁兼容测试中的电源线传导发射和电场辐射发射二项测试，所采取的技术措施具有通用性，对惯导系统中其它部件的电磁兼容改进具有重要的参考价值。     

行波故障测距装置现场校验技术研究

为解决行波故障测距装置的现场检测问题,本文讨论了行波测距装置的测距原理,分析了行波测距装置内双端测距的测距方法,研究了故障行波信号特性及电流互感器及二次电缆等二次传变回路对故障行波传递的影响,探究了一套针对行波测距装置的现场校验平台和方法。检测平台主要包括基于高频线性电流放大器为基础的故障行波再现装置、电磁暂态仿真软件以及GPS卫星同步装置。高频线性电流放大器作为故障行波再现装置,至少能同时输出多路高频电流且配备GPS卫星同步系统,以及考虑了二次传变回路的基于电磁暂态仿真软件的故障模拟仿真系统。检测结果验证了现场校验方法和平台的可行性和正确性。行波测距装置现场校验能够有效发现行波测距装置的技术缺陷、检测行波测距装置测距精度及可靠性。     

电子计算机及外设抗辐射干扰的对策

一.引言 电磁兼容(EMC)包括电磁干扰(EMI)和电磁敏感度(EMS)两个方面。首先引起人们重视的是电磁干扰的测试技术及抑制技术,许多国家都规定了电子电气装置所产生的电磁干扰的极限值,如国标GB 9254—88《信息技术设备的无线电干扰的极限值和测量方法》,该标准规定了信息技术设备(ITE)A级和B级的干扰极限值,以限制干扰通过传导或辐射影响其它装置或系统的正常工作。而最近电磁敏感度的测试技术和对策技术正成为EMC领域的热点。     

便携式电梯曳引钢带缺陷检测装置设计

设计了一种基于视觉与电磁技术的电梯曳引钢带缺陷检测装置,其能够同时检测电梯曳引钢带的内部和表面缺陷,通过电磁检测技术检测钢带的断丝等内部缺陷,通过图像处理技术检测钢带裂纹、磨损等表面缺陷,且装置结构设计紧凑尺寸较小,结构简洁可方便检验人员携带。     

Activity recognition with hand-worn magnetic sensors

Activity recognition is a key technology for realizing ambient assisted living applications such as care of the elderly and home automation. This paper proposes a new activity recognition method that employs hand-worn magnetic sensors to recognize a broad range of activities ranging from simple activities that involve hand movements such as walking and running to the use of portable electrical devices such as cell phones and cameras. We sense magnetic fields emitted by electrical devices and the earth with hand-worn sensors, and recognize what a user is doing or which electrical device the user is employing. We frequently use a large number of different electrical devices in our daily lives, and so we can estimate high-level daily activities by recognizing their use. Our approach permits us to recognize a range extending from low-level simple activities to high-level activities that relate to the hands without the need to attach any sensors to the electrical devices.     

金属胶体纳米材料及研究新进展

简要介绍了金属胶体纳米材料奇特的电磁、光学、催化、理化及传输等性质,主要包括：电磁性质、强度性质和可塑性、传输性质,以及催化和光学性质等。这些性质的应用前景、理论解释及当前的研究进展,同时从胶体聚团的理论出发,提出这些金属纳米材料的奇特性质可能与其在合成纳米结构单元时,形成了某种类晶格点阵有关。     

Thermal and flow analysis of two-dimensional fully developed flow in an AC magneto-hydrodynamic micropump

The effect of fluctuating Lorentz force on the Ac magnetohydrodynamic micropump is studied. A two-dimensional transient fully developed laminar flow and temperature distribution are modeled. The governing Navier–Stokes and energy equations are solved numerically by a finite-difference (ADI) method. The effect of different parameters on the transient and steady flow velocity and temperature, such as aspect ratio, Hartman number, Prandtl number, and Eckert number is studied. The results obtained showed that controlling the flow and the temperature can be achieved by controlling the potential difference, the magnetic flux, and by a good choice of the electrical conductivity. The effect of Stanton number and phase angle is also included, and it is found that at high frequency, the pulsed volume is small which yield a continuous flow instead of pulsating flow, and the magnitude and direction of the flow can be controlled by the phase shift between the electrical and magnetic fields.     

Thermal and flow analysis of a magneto-hydrodynamic micropump

A study of transient fully developed laminar flow and temperature distribution in a magnetohydrodynamic (MHD) micropump is presented. The micropump is driven using the Lorentz force which is induced as a result of interaction between an applied electric field and a perpendicular magnetic field. The governing equations are solved analytically by an eigenfunction expansion method, and numerically by a finite-difference (ADI) method. The numerical and analytical results are found to be in good agreement with each other. The effect of different parameters on the transient velocity and temperature, such as aspect ratio, Hartman number, Prandtl number, and Eckert number is studied. The results obtained showed that controlling the flow and the temperature can be achieved by controlling the potential difference, the magnetic flux, and by a good choice of the electrical conductivity.     

A fully integrated micromachined magnetic particle separator

A prototype micromachined magnetic particle separator that can separate magnetic particles from suspended liquid solutions has been realized on a silicon wafer. The requisite magnetic field gradients are generated by integrated inductive components in place of permanent magnets, which yields several advantages in design flexibility, compactness, electrical and optical monitoring, and integration feasibility (thus enabling mass production). Preliminary experiments have been performed on aqueous suspensions of magnetic beads. At 500 mA of dc current, approximately 0.03 Tesla of magnetic flux density is achieved at the gap between the quadrupoles, and the magnetic particles rapidly move toward the quadrupoles, separate from the buffer solution, and clump on the poles. The magnetic particles clumped on the poles are also easily released when the dc current is removed, achieving the primary purpose of a separator. The device shows that micromachined magnetic components have a high potential in biological or biomedical applications, especially in separating small amounts of cells or DNA that are marked with magnetic beads, especially when close monitoring and control of the process is important     

基于EMD和形态滤波算法的地磁测量抗干扰技术研究

针对地磁匹配定位中,地磁测量受导航载体上电气设备散杂磁场干扰问题,从理论上分析了电气设备产生散杂磁场的机理,通过实测数据总结归纳了散杂磁场特点规律。在与常规小波滤波算法比较的基础上,提出了采用经验模态分解(EMD)和形态滤波消除电气设备磁场干扰地磁测量的算法,从理论上剖析了该算法的优越性及可行性,并提出了根据散杂磁场噪声参数,科学确定需要滤波处理内禀模态函数层数的算法。通过仿真实验及误差分析证明,该算法能够自适应地处理高频交变、非线性、非平稳类磁场噪声,优于常规小波滤波算法,具有更好的降噪效果,有效提高了地磁测量精度和抗干扰性能。     

Mechanical and electrical properties of electroplated copper for MR-imaging coils

Mechanical and electrical properties of electroplated copper films were investigated to be used in an active tracking system for the patient-safe localisation of a catheter in intravascular interventions using magnetic resonance imaging. For this system spiral micro coils with high aspect ratio are fabricated on a planar polyimide foil to be wrapped around a catheter tip. Due to this special assembly method the coils and the copper, respectively, have to withstand high mechanical forces. The influence of the electroplating parameters as current density and shape, temperature and sample motion on the mechanical and electrical properties is investigated. These samples were characterised using nanoindentation, tensile tests, laser profiler and four-point prober. Results show that a low constant current density at a temperature of 40°C and sample motion generate flexible and high-Q copper coils.     

生物细胞超短脉冲电场传感器

描述了生物细胞的电模型。细胞内生物电效应的实验观察包括细胞颗粒的破裂而又不能使细胞膜受到永久性伤害,细胞内游离钙值的突然升高和基因表现的增强。在较高场强时,亚微秒脉冲的作用是感应生物细胞凋亡（编程细胞死亡）和抑制肿瘤细胞的生长。细胞内电效应的应用包括增强基因向细胞核的释放,肿瘤医疗诊断和控制细胞功能（如生物细胞“冻结”,但不一定死亡）。     

耦合胰腺β细胞的同步性分析

胰腺β细胞在分泌胰岛素时会伴随生物放电活动。描述胰腺β细胞放电行为的数学模型有很多,为了理论分析的方便,本文采用具有代表性的三维多项式模型,对两个电耦合胰腺β细胞的同步行为进行了研究。通过构造恰当的李雅普诺夫函数,利用线性矩阵不等式、求解微分不等式获得了模型相应的全局渐近同步和全局指数同步的理论判据,并借助MATLAB进行数值模拟,进一步验证了理论结果的正确。     

原子磁传感器原子气室无磁控温技术

针对原子磁传感器碱金属原子气室对无磁加热的需求,解决磁力仪共振谱线信号信噪比低的问题,使用了差分对的布线方法,采用微加工膜工艺,在陶瓷基板上制备了方形纯铜材质的无磁加热线圈.使用COMSOL Multiphysics多物理场仿真软件分析了线圈在2.2mA直流条件下产生的附加稳态磁场分布情况,结合Pro/Engineer软件构建的铜质气室固定支架及其热仿真分析结果,得到了比较理想的加热线圈固定位置.进一步分析确定了20kHz交流加热方案,最终制作完成了具有3W加热功率和0.1℃控温精度的无磁加热器.实验结果表明:该加热器瞬时磁扰动为2.24pT,满足原子气室无磁加热要求.其结果对原子磁传感器气室的设计及工作参数的优化改进具有一定的参考意义.