螺线管线圈加工工艺

我单位研制的继电器新品中有一种线圈的导线,要求通过额定电流为200A过负载400A,连续通电10min,冲击电流达2500A,而温升不大于45℃,经过计算知,导线面积不得小于56mm2。为满足上述要求,设计了如图1所示螺线管线圈。     

铝合金管件电磁胀形中螺线管线圈的受力研究

针对管件电磁胀形中螺线管线圈的使用寿命短、易损坏的问题,运用ANSYS Maxwell对电磁胀形过程中螺线管线圈所受到轴向与径向电磁力进行有限元仿真。研究了螺线管线圈在高于被胀形管件的情况下,随着螺线管线圈内径的不同,其所受到的电磁力的大小与方向的变化情况。并通过有限元仿真与实验结果对比发现：在螺线管线圈高于管件的电磁胀形中,当螺线管线圈内半径r=11mm时其所受到的力主要来自于管件;当螺线管线圈内半径r=8.5mm时其所受到的力主要来自于自身产生的电磁力。同时螺线管线圈所受到的轴向力是导致其失效的主要原因。     

对置螺线管线圈的多功能检测模型及灵敏度研究

为丰富螺线管型传感器对液压油污染物的检测内容,提出并制作一种基于微流体芯片的对置螺线管型多功能检测传感器。理论推导了对置螺线管线圈的金属颗粒电感检测模型和非金属颗粒电容检测模型。为进一步提高检测灵敏度,试验对比分析了硅钢片对对置螺线管线圈的电感检测和电容检测的灵敏度。试验结果表明,硅钢片能够显著提升对置螺线管线圈的金属颗粒检测灵敏度,60～70μm铁颗粒和160～170μm铜颗粒的检测信噪比分别提升127.44%、222.07%,也能提高对置螺线管线圈的非金属颗粒检测灵敏度,但不显著,140～150μm水滴和240～250μm气泡的检测信噪比分别提升21.92%、7.95%。该研究对提高螺线管型传感器的液压油污染物检测能力提供了技术支撑,对液压系统健康状态监测以及故障诊断具有重要意义。     

面向超高场核磁共振应用的微型接收线圈制作与实验研究

为实现纳升级微量样品检测,结合商业常规核磁共振3.2毫米探头,本文研究了两种类型的自谐振微型接收线圈。当无线传输能量时,探头螺旋管形成射频脉冲激励能量。而微型接收线圈对该能量进行接收后以样品为作用目标,并采集信号回传,把感应获取的磁共振信号传输到探头螺线管。与现有磁共振探头不同,本文提出Pigtail型和Stripline型微接收线圈结构。实测结果显示,线圈谐振频率达128MHz和935.7MHz,应用于3T超导核磁共振设备初步完成了蔗糖波谱的测试分析实验,表明微型接收线圈对提高谱线分辨率有重要作用。     

高分辨率核磁共振波谱仪自动匀场电路

本文简介了高分辨率核磁共振波谱仪自动匀场电路及其工作原理。给出了它的实验结果及在EM-360L波谱仪上的应用。     

低场脉冲核磁共振分析测量仪及其应用

利用低场脉冲核磁共振技术进行物质的定量分析具有快速、准确、无损的特点。本文简要介绍了低场脉冲核磁共振分析测量仪器的构成、发展历史及其在各领域中的应用，并对这一技术在我国的应用前景作了展望。     

永磁低场核磁共振分析仪原理和应用

近年来随着核磁共振技术不断进步,国内许多公司和科研机构成功研制出永磁低场磁共振分析仪,本文以NM120-Analyst型核磁共振分析仪作为这类仪器的代表,简单介绍永磁低场磁共振分析仪的结构原理,再分类讨论永磁低场磁共振分析仪在相关领域的基本应用。实践证明,该类仪器已分别在医学磁共振成像设备教学和培训、食品研究、石油勘探、新能源开发等领域中得到广泛应用。     

基于 Halbach 结构的低场核磁共振主磁体的设计与实现

随着核磁共振不断向便携性和低成本方向发展,核磁共振仪中主磁体的小型化成为了大家关注的重点。为实现核磁共振的小型化,对基于Halbach结构的低场核磁共振主磁体进行了设计与实现。首先,利用ANSYS有限元仿真软件对采用多磁条特定排列形成的Halbach结构进行仿真,对磁条的数量、大小、长度、位置等参数进行调整;其次,根据仿真确定的理想模型参数,实现了主磁体,其为直径108 mm、高170 mm的圆柱体,重4.5 kg,并对其中心磁感应强度和均匀度进行了检测;最后,根据检测结果,设计了一种匀场片矩阵,采用被动匀场的方式将磁体中心5 mm直径球形区域内的均匀度提升至451.68 ppm,中心磁感应强度为221.4 mT。设计中,较好的权衡了磁体性能和生产成本。     

提高电力变压器绕组对地绝缘

通过实验论证用热油循环的方法能够提高大功率变压器绕组对地绝缘。     

船用防爆电磁阀设计

根据电磁阀的应用场合及技术要求进行分析,对防爆型式、电磁铁、密封副进行优化设计,使该电磁阀在工作时具有低表面温度,并具有信号反馈功能,组装后进行了各项型式试验及性能试验。     

Development of a solenoid RF coil for animal imaging in 3 T high-magnetic-field MRI

The purpose of this study was to develop a solenoid coil for use with small animals in a 3 Tesla horizontal magnetic resonance imaging (MRI) system, and to investigate image quality by examination of parameters such as signal-to-noise ratio (SNR) and Q-factor. A receiver solenoid coil was formed by winding three separate coils of copper tape around an acryl cylinder. The cylinder was supported at each end. A euthanized rat weighing 240 g was used as a subject animal for imaging. A cylindrical plastic tube containing a solution of 0.7 g/L CuSO(4) was used as a phantom. Measured SNRs were 985 in the phantom image 995 in the rat. The Q-factor was 89 in the phantom and 84 in the rat, in the loaded condition. The homogeneity of the radiofrequency (RF) field was good and the resolution of the image was sufficient to distinguish internal organs from one another in the abdomen of a rat. This study has demonstrated that a solenoid coil may be used to produce good quality images of small animals.     

高压气体电磁阀设计

提出了一种工作压力60 MPa的高压二通气体电磁阀的设计方法,这种电磁阀具有体积小、重量轻、结构紧凑、气密性好、可靠性高、耐候性好等优点,可广泛应用航空、航天领域以及其它特殊领域的高压气源系统,具有广泛的市场前景.     

低场脉冲NMR横向弛豫信号的反演分析

从第一类积分方程的反演求解入手,推导出了适合低场脉冲核磁共振横向弛豫信号多指数反演的一种解谱算法.对解谱的具体过程进行了详细论述,并对不同信噪比、不同布点方式下的解谱结果进行了对比与分析.本算法对推广低场脉冲核磁共振分析测量技术的应用具有重要的参考价值.     

双螺线管套管结构的液压油金属颗粒检测传感器

提出一种双螺线管套管结构的液压油液金属颗粒检测传感器。理论分析表明,套管结构传感器能够耦合外部螺线管线圈磁场强度和利用双螺线管线圈之间的互感,有效增加金属颗粒通过检测区域的电感变化量。选择电感变化量、平均噪声、信噪比作为传感器检测效果评价指标,对比实验的统计结果表明,检测相同粒径的金属颗粒,套管结构传感器不但未增加检测噪声,而且在电感变化量、信噪比方面都要优于单管结构传感器,随着铁颗粒粒径的增加,其检测效果的优越性越明显。检测直径为110～120μm铁颗粒和铜颗粒时,电感变化量分别提升2. 4和1. 7倍,其检测信噪比均提升1. 8倍。颗粒检测下限实验表明,套管结构传感器能够检测直径大于30μm的铁颗粒和直径大于90μm的铜颗粒。研究对提高螺线管型电感检测传感器的检测灵敏度具有参考价值。     

Precision field averaging NMR magnetometer for low and high fields, using flowing water

The separated oscillatory field magnetic resonance technique (Ramsey technique) has been employed with flowing water as a volume averaging magnetometer. Polarization and detection were performed in high fields, external to the volume over which the magnetic field was to be averaged. An accuracy of a few parts in 10(7) at a nominal field of 18 G was obtained. The technique is applicable, using standard equipment, for the measurement of fields ranging from kilogauss down to milligauss.     

Magnetization measurements using the field gradient of a high-field solenoid

By using a high-field solenoid, the force on a magnetic sample resulting from a field gradient becomes large and measurements using the Faraday (or Curie) method are greatly simplified. By using an electronic analog dividing circuit, curves of magnetic moment or susceptibility versus field or temperature can be quickly and easily recorded. Various examples are given.     

高感电磁阀驱动恒流源的设计

电磁阀在核工业中应用广泛,安全稳定地运行是核工业发展的要求,对电磁阀的稳定驱动是电磁阀长期运行的保障.针对供电电压、温度、负载变化等因素造成电磁阀驱动电流稳定度低、可靠性差、功耗大等问题,设计一款基于STM32的可调节DC/DC恒流源驱动.该恒流源主要包括全桥DC/DC变换器电路、串联负反馈式稳流电路和STM32控制系...     

Design and optimization of coil structure based on the uniformity of core temperature field

Coil structure size parameters during electromagnetic induction heating affect the temperature field and heating rate of a carbon fiber-reinforced polymer (CFRP) shell. In this study, a finite element analysis model is established on the basis of a single-screw coil structure, and the influence of coil diameter, length, turns, and position relationship on the temperature field distribution and heating rate of the CFRP shell is studied. According to image entropy theory, the influence of coil structure size parameters on the uniformity of a temperature field distribution is analyzed. Furthermore, the accuracy of the coil structure size parameters with respect to temperature field variation is verified with a CFRP induction heating experiment. This study provides theoretical support and a verification method for the selection, design, and optimization of the coil structure size parameters of CFRP shells during induction heating.