Magnetic Measurement Method Research Articles

Fiber optic magnetic field sensor based on a magnetic-fluid-induced phase-shift FLRD

A magnetic field sensing system based on a phase-shift fiber loop ring-down (FLRD) technique and multi-mode interferometer (MI) coated with magnetic fluid (MF) is proposed and demonstrated. The MI is constructed by splicing a segment of no-core fiber between two sections of single-mode fibers, which is then immersed in MF to serve as a sensing head with the advantages of simple fabrication and specific magnetic sensitivity. Due to the magnetic refractive index tunable properties of the MF, the magnetic-field-dependent loss will be introduced in the fiber loop by the sensing head. Such magnetic-induced loss would be accumulated during the round trip of the optical carrier and reflected on the phase information of the modulated signal. The phase-shift changes with the applied magnetic field strength, enabling magnetic field sensing through phase-shift measurements. The sensing system is experimentally demonstrated and a sensitivity of 0.704×10−3deg/Gs in the linear region is achieved. Moreover, the stability and repeatability of the system are verified, leading to a promising method for magnetic field measurements.

Research on measuring method of self-mixing interference magnetic field based on Faraday effect

In this paper, the magnetic field measurement method of laser self-mixing interference based on the Faraday effect is proposed. The polarization plane of the linearly polarized light is changed by the terbium gallium garnet crystal with the influence of the magnetic field. The light modulated by the magnetic field reentered into the laser cavity through the Brewster window and formed the self-mixing effect. The theoretical analysis of the self-mixing interference model based on the Faraday effect is conducted, which explains essential features of the experimental results. The magnetic field is measured by the peak-to-peak value of self-mixing interference signal. The experimental results show that the relative error of the magnetic field measurement is within ±1.6%. The measurement method has the advantage of simple and compact structure with strong anti-interference ability.

UAV-Based Environmental Magnetic Field Measurement Method Using a TMR Sensor

UAV-Based Environmental Magnetic Field Measurement Method Using a TMR Sensor

Study on the sealing performance of high-pressure flanges by a magnetic measurement method of bolt axial force

Under high-pressure conditions, flange sealing often fails due to inadequate bolt pre-tension, leading to unstable pressurization or leakage. Assessing the integrity of high-pressure flange sealing presents challenges, constrained by operational conditions, complex equipment integration, and associated costs. This study introduces a method to evaluate flange sealing using magnetic measurements of bolt axial forces. A novel device developed using the magnetoelastic method efficiently and conveniently measures these forces under various internal pressures. The results show a linear relationship between magnetic signals and bolt axial forces at nominal pressures, whereas excessively high pressures cause anomalous changes in magnetic signals, indicative of bolt plastic deformation. Finite element simulation analyzed the changes in bolt axial force and gasket contact stress due to internal pressures, leading to an empirical formula that correlates these variables under varying pressures. The study also explored the impact of uneven pre-tensioning and gasket material on sealing contact stress. A sealing contact surface model, established based on actual roughness profile parameters, enabled the simulation and formulation of an exponential relationship between contact stress and sealing clearance. This foundation facilitated the creation of a leakage prediction model that incorporates bolt axial force parameters, thus enabling a quantitative assessment of flange sealing performance. This research provides a practical approach to evaluating the sealing performance of operational high-pressure flanges.

Deep learning based tracking reconstruction and magnetic field measurement research in the muon g-2 experiment

The Run1 result of the Fermilab muon g-2 experiment have shown a 4.2 standard deviation between the experimental measurement and theoretical prediction of aμ, strongly indicating a new physics signal. The Fermilab experiment already accumulated 21 times more data compared to the BNL experiment. The J-PARC muon g-2 experiment will collect 3.5 times the statistics compared to Fermilab. With the increases in the collected data volume, and limited by the speed and accuracy, the existing tracking reconstruction and magnetic field measurement method may not fully satisfy the requirement of the experiment. The breakthrough of the deep learning inspires new analysis method in the muon g-2 experiment. In this proceeding, we will present some preliminary research on the tracking reconstruction based on Recurrent Neural Network (RNN), Graph Neural Network (GNN) and the magnetic field measurement based on Physics Informed Neural Network (PINN). The preliminary results show that the deep learning method has enormous potential in these topics.

Design and Implementation of a Linear Active Disturbance Rejection Control-Based Position Servo Control System of an Electromotive Valve for Exhaust Gas Recirculation.

An exhaust gas recirculation (EGR) valve is used to quickly and dynamically adjust the amount of recirculated exhaust gas, which is critical for improving engine fuel economy and reducing emissions. To address problems relating to the precise positioning of an electromotive (EM) valve under slowly varying plant dynamics and uncertain disturbances, we propose a servo control system design based on linear active disturbance rejection control (LADRC) for the EGR EM valve driven by a limited angle torque motor (LATM). By analyzing the structure of the LATM and the transmission, the dynamic model of the system is derived. In addition, to solve the problems caused by slowly varying plant dynamics and uncertain disturbances, we combine the effects of uncertain model parameters and external disturbances as the total disturbance, which is estimated in real time by an extended state observer (ESO) and then compensated. In addition, accurate angular information is obtained using a non-contact magnetic angle measurement method, and a high-speed digital communication channel is established to help implement a closed-loop position control system with improved responsiveness and accuracy. Simulation and experimental results show that the proposed servo system design can effectively ensure the precision and real-time performance of the EM valve under slowly changing plant dynamics and uncertain disturbances. The proposed servo system design achieves a full-stroke valve control accuracy of better than 0.05 mm and a full-stroke response time of less than 100 ms. The controlled valve also has good robustness under shock-type external disturbances and excellent airflow control capability. The repeatability of the airflow control is generally within 5%, and the standard deviation is less than 0.2 m3/h.

Visualization evaluation of damage degree on remanufacturing cores based on residual magnetic scanning measurement

A novel residual magnetic scanning measurement (RMSM) method with easy operation, low cost and good universality based on metal magnetic memory (MMM) is proposed to evaluate the damage degree of remanufacturing cores. The two-dimensional (2-D) grayscale maps of residual magnetic field (RMF) and residual stress can be visualized, respectively, by constructing the relationship among magnetic field, stress and pixel gray value. The contour of high residual stress zone which enters the plastic stage can be extracted from the 2-D grayscale map based on the gray thresholds representing the yield strength. The defect size can also be inverted with the evaluation error below 10 % and the resolution reaching 0.2 mm. To prove the feasibility of RMSM applying into the damage evaluation on remanufacturing cores, the RMF distribution and the high residual stress zone of a damaged gear are also visualized. The 2-D grayscale maps of RMF and residual stress can clearly show the profile of gear and the plastic deformation damage zone. The RMSM method can facilitate the accurate damage evaluation on remanufacturing cores and provide the support for the subsequent repairing process design.

A Non-Steady State NMR Effect Based Time-Varying Magnetic Field Measurement Method and Experimental Apparatus

A Non-Steady State NMR Effect Based Time-Varying Magnetic Field Measurement Method and Experimental Apparatus

Magnetic property measurement method using coaxial H coil

Magnetic property measurement method using coaxial H coil

Magnetometric SQUID Systems and Magnetic Measurement Methods for Biomedical Research

Magnetometric SQUID Systems and Magnetic Measurement Methods for Biomedical Research

Extremely low-frequency magnetic spectrum measurement method based on the NV center in diamond

Abstract In this paper, we establish a set of schemes to generate, detect, and identify the multi-frequency magnetic field in the extremely low-frequency range. Based on the magnetic sensitivity of nitrogen-vacancy centers in diamond, the schemes adopt frequency closed-loop proportion-integration-differentiation locking and microwave modulation and demodulation to obtain magnetic field information. A set of multi-coil mutual inductance devices is used to generate a multi-frequency AC magnetic field. In the schemes, the DenseNet network structure is used to train and identify the magnetic field information, with a recognition rate of 99.16%. When the Net is used to identify noisy signals, it still maintains an average recognition rate of 95.18% for random frequency noisy signals. This generating, detecting, and identifying schemes of the multi-frequency magnetic field in the extremely low-frequency range based on quantum sensors in this paper provides a novel idea for the future application of quantum sensors in biomedicine.

Analisis Metode Magnetik pada Daerah Manifestasi Panas Bumi Karangrejo, Kabupaten Pacitan

Geothermal energy is one of the natural resources found in Pacitan Regency, alongside mining and geotourism. Geothermal manifestations in Pacitan Regency take the form of hot springs located at two points: Tinatar in the Punung District and Karangrejo in the Arjosari District. This research primarily focuses on magnetic measurement methods at the Karangrejo hot spring manifestation to provide information about its subsurface geological conditions. Data acquisition was conducted using 2 Proton Precision Magnetometers (PPM) of the Geotron G-5 brand as both base and rover instruments. The acquired data was processed with diurnal correction, IGRF correction, separation of residual-regional anomalies, and Reduce to Pole (RTP) transformation. The research results show magnetic anomaly variations in the study area ranging from -220 nT to 200 nT. Some geological structures that could potentially be associated with the Karangrejo hot spring manifestation are north-south trending faults and northeast-southwest trending faults, while the lithology of the study area is dominated by kaolin alteration and andesite rocks. It is estimated that the Karangrejo geothermal system is a fault-hosted geothermal system resulting from fault activity.

Evaluation of electrical activity at the carpal tunnel area in response to median nerve elbow stimulation using magnetoneurography

ObjectiveTo develop a magnetic field measurement method in the carpal tunnel area in response to electrical median nerve stimulation at the elbow and evaluate its usefulness. MethodsFive healthy subjects participated. The magnetic field recording evoked by median nerve electrical stimulation at the elbow with electrical intensity that minimized the pronator quadratus and flexor carpi radialis muscle response was measured with 132-channel superconducting quantum interference device magnetoneurography. The current distributions were reconstructed from magnetic fields with the spatial filter method. The magnetic fields evoked by electrical stimulation at the index distal interphalangeal joint were also measured. ResultsAfter median nerve elbow stimulation, intra-axonal current and inward currents flowing perpendicularly to the nerve pathway were visualized. The mean ± SD inward current intensity at the center of the carpal tunnel area was significantly larger with elbow stimulation than with index distal interphalangeal joint stimulation: 1.11 ± 0.65 nAm versus 0.51 ± 0.15 nAm (p = 0.047). ConclusionsMagnetic field measurement in the carpal tunnel area with adjusted submaximal stimulation at the elbow can detect larger signals compared with digit stimulation. SignificanceThis method has the potential to be more useful for the examination of carpal tunnel syndrome patients.

Organo-Functionalized Lacunary Double Cubane Type Oxometallates: Synthesis, Structure, and Properties of [(MIICl)2(VIVO)2{((HOCH2CH2)(H)N(CH2CH2O))(HN(CH2CH2O)2)}2] (M = Co, Zn).

Organofunctionalized tetranuclear clusters [(MIICl)2(VIVO)2{((HOCH2CH2)(H)N(CH2CH2O))(HN(CH2CH2O)2)}2] (1, M = Co; 2, M = Zn) containing an unprecedented oxometallacyclic {M2V2Cl2N4O8} (M = Co, Zn) framework are prepared by solvothermal reactions. The new oxo-alkoxide compounds are fully characterized by spectroscopic methods, magnetic susceptibility measurement, DFT and ab-initio computational methods, and complete single crystal X-ray diffraction structure analysis. The isostructural clusters are formed of edge-sharing octahedral {VO5N} and trigonal bipyramidal {MO3NCl} units. Diethanolamine ligates the bimetallic lacunary double cubane core of 1 and 2 in an unusual two-mode fashion, unobserved previously. In the crystalline state, the clusters of 1 and 2 are joined by hydrogen-bonds to form a three-dimensional network structure. Magnetic susceptibility data indicate weakly antiferromagnetic interactions between the vanadium centers [Jiso(VIV-VIV) = -5.4(1); -3.9(2) cm-1], and inequivalent antiferromagnetic interactions between the cobalt and vanadium centers [Jiso (VIV-CoII) = -12.6 and -7.5 cm-1] contained in 1.

Magnetic Sensor-Based Switching Cabinet Busbar Current Measurement Method

Traditional switchgear current measurement techniques use closed-loop current modules to accurately measure and control current, and in switchgear, there is also interphase interference, these modules usually require a large core that surrounds the entire busbar as well as a shielded shell, because the compensation current generated inside the module is proportional to the busbar current, so the power consumption can be as high as several watts. In view of this, this paper proposes a magnetic sensor-based switch cabinet busbar current measurement method, and through theoretical deduction, it is determined that the magnetic sensor with two magnetic sensitive directions opposite and vertically placed in the busbar can eliminate the interference from the busbar phase and the stray field. Through simulation analysis, it was determined that the opening hole of the switch cabinet bus row was a circular hole, and the placement of the two magnetic sensors was at the edge of the circular hole, so that the practical application of the method in the switch cabinet had certain guiding significance.

Stray Magnetic Field Measurement Method of Magnetic Hysteresis Curve of Open-Ended Sensor and Actuator Cores

In the design and development of measurement systems, such as magnetometric security systems or sophisticated devices such as satellites, it is necessary to consider the magnetic properties of all its parts and components, especially if it contains any magnetometric subsystem. The magnetic parameters of the materials are generally well described by the manufacturers in relation to their unprocessed raw state. However, their magnetic properties change as the subsequent machining or heat treatment is performed. These behavioral reactions of the material may lead to changes in its hysteresis during the magnetization cycles. This effect is necessary to consider, especially in the case of metallic ribbons, the magnetic characteristics of which are usually estimated by measurements performed on toroidal cores. Since the magnetic properties of a toroidal core differ from the magnetic properties of the preferably used open-ended samples, the corresponding measurement method needs to be used to determine its magnetic characteristics. Therefore, in the proposed article, the authors present a stray magnetic field-based method and measuring workstation intended to measure the magnetic hysteresis curves of the ferromagnetic open-ended samples used in the applications concerning the magnetometric systems and stabilization subsystems of small satellites. The physical background of the measurement method is described in detail, as well as the hardware and software used. The magnetic hysteresis curves of a small satellite electromagnetic actuator were measured as an example of an open-ended ferromagnetic component produced from amorphous ribbons, the permeability of which differs in comparison to manufacturer-stated permeability of raw amorphous material. The results are supplemented by measurements of the core characteristics of the used magnetometer probe, as well as by the characteristics of the semi-produced materials used for the production of both investigated cores. The primary advantage of the presented measurement method lies in the ability of design validation prior to the production of the final component and its assembly.

3-D Positioning Method of Pipeline Robots Based on a Rotating Permanent Magnet Mechanical Antenna

At present, the 3-D positioning of pipeline robots is limited by complex structures, large device sizes, and difficulties in the miniaturization of the sensor array. In this article, a multipoint magnetic field measurement method (MFM) is proposed for the spatial positioning of pipeline robots. The method can effectively obtain the 3-D coordinate positioning of pipeline robots in a short range, without complex sensor arrays, and without knowing the direction of the pipeline in advance. Furthermore, to address the problem in which weak magnetic field value is very susceptible to background noise and ferromagnetic interference in the environment, a dislocation superposition method (DSM) is developed to process the measured signals. In the MFM, a rotating permanent magnet mechanical antenna is used as the transmitter of low-frequency magnetic signals due to its advantages of small size, low energy consumption, and high radiation efficiency. Moreover, a single three-axis fluxgate sensor is used to measure the magnetic signal at multiple points. Finally, to verify the superiority of the proposed MFM and DSM, experiments are carried out in a seabed engineering laboratory. The test results show that the average absolute error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${x}$ </tex-math></inline-formula> -axis positioning is 0.04 m, the average absolute error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${y}$ </tex-math></inline-formula> -axis positioning is 0.01 m, and the average absolute error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${z}$ </tex-math></inline-formula> -axis positioning is 0.07 m.

Current sensor based on diamond nitrogen-vacancy color center

High precision current measurement is very important for the calibration of various high-precision equipment and the measurement of other precision detection fields. A new current sensor based on diamond nitrogen-vacancy (NV) color center magnetic measurement method is proposed to realize the accurate measurement of current. This new current method can greatly improve the accuracy of current measurement. Experiments show that the linearity of the current sensor based on diamond NV color center can reach up to 33 ppm, which is superior to other current sensors and solves the problem of low linearity. When the range of input current is 5–40 A, the absolute error of the calculated current is less than 51 μA, and the relative error is 2.42 × 10−6 at 40 A. Combined with the research content and results of the experiment, the application of the current sensor in the field of current precision measurement is prospected.

A Seawater Conductivity Measurement Method Based on Magnetic Resonance Coupling

This paper proposes a magnetic resonance coupling seawater conductivity measurement method with a dual-coil structure. The passive transceiver coil is composed of two detection coils and capacitive elements placed in seawater. The seawater conductivity measurement is realized by analyzing the relationship between the transmission loss of the resonant magnetic field between the passive transceiver coils in the seawater and the seawater conductivity. In the article, the magnetic resonance coupling measurement method is established and analyzed, the circuit model of the magnetic resonance coupling measurement system transmitted in seawater is established, the experimental device is set up for laboratory testing, and the corresponding test situation is simulated by finite element electromagnetic modelling. The test and simulation results show that the measurement method is feasible; the system has the best performance at the resonant frequency, especially for low-conductivity conditions, and better sensitivity. In addition, the resonant frequency increases, and the conductivity resolution of the measurement system for seawater increases.

The In-Plane Magnetic Field Measurement Method of SC/MR Mixed Sensor and Its Three-Axis Magnetic Sensor With Integrated Magnetic Concentrator

Superconductor/magnetoresistance (SC/MR) mixed sensor has the advantage of ultrahigh sensitivity and is thought to be a promising candidate for weak magnetic field detection. However, it has no effect on the magnetic field in the superconducting flux-to-field transformation amplifier (SFTA) plane, which limits its applications in 3-D magnetic field detection. Here, we present a new architecture of SC/MR mixed sensor with only one integrated magnetic concentrator (IMC) to realize the in-plane magnetic field measurement. Firstly, the conversion efficiency, defined as the in-plane magnetic changing to the out-plane magnetic field by the IMC and SFTA of mixed sensor, was systematically studied by the finite element analysis method, the results show that the high conversion efficiency is from the combined action of superconducting diamagnetism and magnetic concentrator of soft magnetic materials. Then, a serial prototype mixed sensors with different IMC relative configuration sizes were prepared and their experimental performances were obtained. Indeed, the mixed sensor with IMC can simultaneously measure the in-plane and out-of-plane magnetic fields, furthermore, the conversion efficiency changes as the function of the relative configuration size is consistent well with the simulation result. Finally, a three-axis SC/MR mixed sensor scheme and its corresponding three-axis magnetic field decoupling method based on this method were also proposed, showing the obvious capability of three-axis magnetic field measurement. Our work is meaningful to the development of a three-axis weak magnetic field detection.