巨磁阻传感器在裂解炉管渗碳层厚度检测的应用

裂解炉管在裂解石油的过程中,会发生渗碳现象。当渗碳到一定的深度,将会引起炉管材料的塑性降低和脆裂,导致重大的经济损失和诱发安全事故。文中采用铁片叠加,模拟渗碳层厚度增加,引起磁性增加的特性采用巨磁阻传感器来检测。基于涡流检测原理,进行了渗碳层模拟及探测的实验研究,得出巨磁阻传感器在弱磁场的检测中灵敏度高,可靠性好,适合炉管的渗碳层厚度检测。     

基于巨磁阻的金融机具传感器

与传统的磁敏传感器比较，巨磁阻传感器具有灵敏度高、可靠性好、测量范围宽、体积小、价格低等优点。介绍了巨磁阻传感器的工作原理和输出特性。以巨磁阻传感器为磁敏元件，研发成功国家专利产品点钞机的巨磁阻传感器。实践表明，采用巨磁阻传感器可以检测到各国不同纸币上的微小磁信号。     

各向异性磁阻传感器的原理及其应用

详细介绍了各向异性磁阻传感器的物理机理，并以HMC1002为例说明其测量原理、芯片以及电路的主要特点，给出了弱磁测量的结果与分析。将HMC1001，HMC1002与倾角传感器相结合，可用于姿态的测量。并介绍了其在场源相关性识别中的作用和应用电路。分析了各项异性磁阻传感器的优点及前景预测。     

基于Matlab在漏磁检测中进行的滤波器设计

应用Matlab方法，在漏磁检测中进行滤波器编辑，对信号进行滤波，以滤除外部环境所带来的突变信号，保证了缺陷的正确判定。     

一种管道漏磁无损检测传感器的设计与实现

针对管道缺陷检测的现状,研制了一种适用于输油、输气管道的漏磁无损检测传感器,该传感器由磁敏器件、励磁模块、导轮等部分组成,具有灵敏度高、可用性强的特点,能满足不同管径和工况的管道缺陷检测,内容涉及漏磁检测、磁敏器件的选择、永磁体的优化以及导轮的设计等。     

先进磁电子材料和器件

总结了包括巨磁阻传感器、磁电耦合器件和磁性存储器件在内的几类主要的先进磁电子器件.分别介绍了这几类器件的材料、结构、工作原理和器件性能,以及它们的用途.在此基础之上,展望了磁电子材料和器件领域的发展前景和发展方向.     

基于PYTHON的多通道漏磁检测系统设计

针对钢管漏磁检测中存在单通道探头检测效率低,缺陷定量困难,仪器不便携带等难题,根据漏磁检测原理设计了一套多通道漏磁检测系统。应用三轴磁场传感器芯片研制了四通道漏磁检测探头;采用Python语言编程控制Arduino开发板进行信号采集、处理及显示;测试系统检测性能并开展缺陷定标试验。结果表明,三轴磁场传感器不仅能高效、准确检测出钢管缺陷,而且具有较高的检测灵敏度;多通道漏磁检测系统既能实现对对钢管的实时检测和显示,且界面简单友好,携带方便。对钢管的漏磁检测具有极高的实用性和市场应用价值。     

漏磁检测多排传感器的数据修正理论及方法

漏磁检测因其显著的技术优势,被广泛应用于无损检测铁磁性构件中的缺陷,尤其是在油气管道的内检测领域。 漏磁 检测信号的空间分辨率由传感器的排布密度决定,但传感器的排布密度受其尺寸限制,尤其是对单排传感器。 因此为提升检测 信号的空间分辨率,传感器的多排、错排布置是简单易行的方法。 由于多排传感器所处位置的背景磁场不同,不同背景磁场对 检测信号的影响规律尚不清晰,因此需要对以上问题进行理论分析,并提出对多排传感器检测数据进行修正的方法。 本研究基 于磁荷理论,将缺陷检测信号划分成背景磁场和缺陷漏磁场两部分的叠加,给出了两者叠加的规律。 基于此提出了对多排传感 器的检测数据进行修正的方法,并通过 COMSOL 仿真和实验结果验证了所提方法的有效性。     

InSb伪币检测传感器的研究

】文中介绍了以磁阻效应为工作原理的ＩｎＳｂ伪币检测传感器的设计和制作。这种传感器的主要特点是高分辨率、非接触、体积小、重量轻和使用寿命长。性能测试结果表明，在０．３Ｔ磁场内，磁阻灵敏度为１．８～３。     

桥梁缆索断丝微磁检测技术研究

基于铁磁材料的剩磁现象,建立了桥梁缆索断丝缺陷漏磁场分析有限元模型,分析了断口处钢丝表面及空气中的漏磁场分布规律,计算了空气层中漏磁场的强度,为微磁探伤技术的应用提供了理论依据;搭建了基于微磁原理的缆索断丝检测试验平台,采用三维磁阻式传感器对缺陷缆索的模拟试件进行了探伤实验,试验结果证实了缆索钢丝中剩磁场的存在及断丝处漏磁场的可检性,分析了不同断丝数量及不同断丝位置的漏磁信号特征,验证了理论分析的正确性及微磁检测方法的可行性;基于微磁原理的缆索断丝无损检测系统,可省略笨重的激磁单元,为实现检测装置的节能化与轻量化设计提供了科学依据。     

A Giant-Magnetoresistance Sensor for Magnetic-Flux-Leakage Nondestructive Testing of a Pipeline

This paper presents the method of magnetic-flux-leakage (MFL) detection and the characteristics of a giant-magnetoresistance (GMR) sensor. An experimental apparatus that uses a GMR sensor for oil-pipeline inspection is described. A permanent-magnet assembly was used to excite MFL signals. The signal from the GMR sensor is preamplified with an appropriate gain. The result shows the magnetic-flux-leakage method based on a GMR sensor can detect small defects in an oil pipeline.     

基于GMR的二维焊缝检测传感器的设计与实现

简述了基于GMR的二维焊缝检测传感器。为解决焊接加工自动化过程中焊缝的跟踪检测，将GMR焊枪悬浮高度传感器、焊缝检测传感器以及相应的微处理器有机集成，从而使传感器实现小型化智能化，减少对工件检测的死区范围。该传感器与自动焊接机组成的焊缝跟踪系统，焊缝跟踪精度高、响应速度块，减少了焊缝轨迹空间捕捉算法的复杂挫。     

基于GMR的三维智能传感器的设计与实现

简述了基于GMR的三维焊缝检测传感器.为解决焊接加工自动化过程中空间焊缝的跟踪检测,将GMR焊枪悬浮高度传感器、焊缝检测传感器以及相应的微处理器有机结合并集成,用于检测跟踪三维焊缝.基于这种三维智能传感器的焊缝跟踪系统,能够根据空间焊缝的多变性而采用不同的检测方法,大大减小了焊缝检测的盲区.实验结果表明:焊缝跟踪精度高并能够检测出空间复杂三维焊缝,达到设计要求.     

GMR array uniform eddy current probe for defect detection in conductive specimens

The usage of eddy current probes (ECP) with a single magnetic field sensor represents a common solution for defect detection in conductive specimens but it is a time consuming procedure that requires huge amount of scanning steps when large surface specimens are to be inspected. In order to speed-up the nondestructive testing procedure, eddy current probes including a single excitation coil and an array of sensing coils present a good solution. The solution investigated in this paper replaces the sensing coils for giant magneto-resistors (GMRs), due to their high sensitivity and frequency broadband response. Thus, the ECP excitation coil can be driven at lower frequencies than the traditional ones allowing defects to be detected in thicker structures.In this work an optimized uniform eddy current probe architecture including two planar excitation coils, a rectangular magnetic field biasing coil and a GMR magnetometer sensor array is presented. An ac current is applied to the planar spiral rectangular coil of the probe, while a set of GMR magnetometer sensors detects the induced magnetic field in the specimens under test. The rectangular coil provides the DC uniform magnetic field, assuring appropriate biasing of the GMR magnetometers of the probe, setting-up the functioning point on the linear region and at the same branch of the GMR static characteristics. The differences on the images obtained for the same specimen for each GMR are reduced if all sensors are biased on the same working point. Elements of the automated measurement system used to inspect the plate under test using the proposed eddy current probe, including a validation procedure based on a 2D template matching algorithm and the corresponding experimental results are included in the paper.     

新型压电传感器在加工工艺监测中的应用

工艺流程连续跟踪监测技术是自动化企业追求“无次品生产”的关键，而这一关键的核心又完全有赖于选择相应的传感器。实践证明，压民式传感器因其具有质量稳定、性能可靠、灵敏度高，加之其动态范围大、频率响应宽以及硬而耐磨，尺寸小，易于安装和抗过载安全性好等优点而格外胜任此项工作。     

Miniature sensor suitable for electronic nose applications

A major research effort has been devoted over the years for the development of chemical sensors for the detection of chemical and explosive vapors. However, the deployment of such chemical sensors will require the use of multiple sensors (probably tens of sensors) in a sensor package to achieve selective detection. In order to keep the overall detector unit small, miniature sensors with sufficient sensitivity of detection will be needed. We report sensitive detection of dimethyl methylphosphonate (DMMP), a stimulant for the nerve agents, using a miniature sensor unit based on piezoresistive microcantilevers. The sensor can detect parts-per-trillion concentrations of DMMP within 10 s exposure times. The small size of the sensor makes it ideally suited for electronic nose applications.     

Finite-element method modeling in 4 and 16 sensors electric-charge tomography systems for particles moving in pipeline

Tomography determines the distribution of materials by the use of sensors that captures information on the materials in regions of interests such as cross-section of pipelines or process vessels. In this paper, system equation for the 4 and 16 sensor systems is derived based on the Cartesian coordinate system, the elements’ technique of the finite-element method, Gauss’s and Coulomb’s theories. The derived equation relates the electric charge distribution in a pipeline cross-section and the installed sensors at the periphery of the pipeline. From the developed system equation, sensitivity matrices for the two systems resulting from the assumed spatial electric-charge distribution on the pipeline cross-section were made. The developed sensitivity matrices of the two systems were in turn used for the reconstruction of the tomography images or concentration profiles of the moving particles across the pipeline cross-section. This research is carried out in order to explore the possibilities of reducing the 8 to 32 electrodynamic sensor systems that are normally used in electric charge tomography systems. A comparison between the reconstructed images of the 4 and 16 sensor systems was made, and the results show that the 16 sensor system produced more accurate images than the 4 sensor system. Nevertheless, the 4 sensors’ system could be used in quantitative applications.     

基于时空局部学习的集成自适应软测量方法

集成软测量方法已被广泛应用于流程工业关键质量参数实时估计。但是,常规集成建模方法在基模型构建过程中往往局限于挖掘样本之间的空间关系,忽略了样本间的时序关系,从而导致过程局部状态挖掘不充分、基模型间多样性不足等问题。其次,传统软测量方法由于缺乏自适应机制而无法有效处理过程时变特征,从而导致模型性能发生退化。为此,提出一种基于时空局部学习(STLL)的集成自适应软测量方法。该方法首先通过移动窗口、即时学习技术分别挖掘样本间的时序关系和空间关系,并采用统计假设检验实现冗余状态剔除,进而构建多样性的时空局部高斯混合回归(GMR)模型。然后,基于在线选择性集成策略实现局部预测结果的自适应融合。此外,引入双重自适应机制以缓解模型性能退化问题。实验结果显示,相较于非自适应全局GMR模型、时间局部学习集成GMR模型、空间局部学习集成GMR模型,所提方法在金霉素发酵过程中的预测精度分别提升了70.3%,14.9%,27.8%;在脱丁烷塔过程中,分别提升了31.9%,21.2%,19.3%。     

Coherent optical fiber interferometric sensor for incipient cavitation index detection

Optical fiber sensors (OFSs) are nowadays widely adopted in many different fields and applications. Cavitation in pipeline systems is one of the main concerns of engineers because of its serious consequences for the lifetime of pipelines and on the performance of hydraulic devices. Among other useful parameters the incipient cavitation index is one of the most important because it represents the very beginning of the phenomenon. The present paper discusses the possibility of using optical fiber technology to detect cavitation in a pipeline. The experimental system exploits an interferometric fiber optical sensor based on a coherent demodulation scheme, avoiding the need for working point stabilization systems and coping with the polarization fading. Several dispositions and geometries for the sensors have been tested to select the most efficient solution. The results are then compared with cavitation indexes calculated following the standard procedure, using accelerometer measurements, to prove the optical fiber sensors’ effectiveness.