scholarly journals A High-Frequency Phase Feature for the Measurement of Magnetic Permeability Using Eddy Current Sensor

2021 ◽  
Author(s):  
Mingyang Lu ◽  
Xiaobai Meng ◽  
Ruochen Huang ◽  
Liming Chen ◽  
Anthony Peyton ◽  
...  
Keyword(s):  
Magnetic Permeability ◽  
High Frequency ◽  
Impedance Measurement ◽  
Destructive Testing ◽  
Zero Crossing ◽  
Linear Feature ◽  
Signal Features ◽  
Fast Processing ◽  
Lift Off ◽  
Phase Term

Electromagnetic sensing has been used for diverse applications of non-destructive testing, including the surface inspection, measurement of properties, object characterization. However, the measurement accuracy could be significantly influenced by the lift-off between sensors and samples. To address the issue caused by lift-offs, various strategies have been proposed for the permeability measurement of ferromagnetic steels, which mainly involves different sensor designs and signal features (e.g., the zero-crossing feature). In this paper, a single high-frequency scenario for the permeability retrieval is introduced. By combining the signal of two sensing pairs, the retrieval of magnetic permeability is less affected by the lift-off of sensors. Unlike the previous strategy on reducing the lift-off effect (directly taking the phase term out of the integration) using the Dodd-Deeds analytical method, the proposed method is based on a high-frequency linear feature of the phase term. Therefore, this method has the merit of high accuracy and fast processing for the permeability retrieval (a simplified version of Dodd-Deeds analytical formulas after the integration). Experimental measurement has been carried out on the impedance measurement of designed sensors interrogating ferromagnetic dual-phase steels. For sensor lift-offs of up to 10 mm, the error of the permeability retrieval is controlled within 4 % under the optimal frequency.

scholarly journals Thickness Measurement of Metallic Film Based on a High-Frequency Feature of Triple-Coil Electromagnetic Eddy Current Sensor

2020 ◽  
Author(s):  
Mingyang Lu ◽  
Liming Chen ◽  
Xiaobai Meng ◽  
Ruochen Huang ◽  
Anthony Peyton ◽  
...  
Keyword(s):  
High Frequency ◽  
Peak Frequency ◽  
Magnetic Films ◽  
Thickness Measurement ◽  
Small Error ◽  
Metallic Film ◽  
Change Rate ◽  
Lift Off ◽  
Frequency Feature ◽  
Phase Term

Previously, various techniques have been proposed for reducing the lift-off effect on the thickness measurement of the non-magnetic films, including the peak-frequency feature and phase feature in the Dodd-Deed analytical formulation. To realise a real-time feedback response on the thickness monitoring, the phase term in the Dodd-Deeds formulation must be taken off the integration. Previous methods were based on the slow change rate of the phase term when compared to the rest of the term – the magnitude term. However, the change rate of the phase term is still considerable for a range of working frequencies. In this paper, a high-frequency feature has been found. That is, the ratio between the imaginary and real part of the phase term is proportional to the integral variable under high frequencies. Based on this proportion relationship, the phase term has been taken out; and a thickness algorithm has been proposed. By combing the measured impedance from the custom-built sensor (three coils), the thickness of the metallic film can be reconstructed. Experiments have been carried out for the verification of the proposed scenario. Results show that the thickness of the metal film can be reconstructed with a small error of less than 2 %, and immune to a reasonable range of lift-offs.

High-frequency magnetic permeability of single- and multilayered (Co41Fe39B20) x (SiO2)100–x nanocomposites

2016 ◽  
Vol 58 (12) ◽  
pp. 2453-2456 ◽  
Author(s):  
O. S. Tarasova ◽  
A. V. Sitnikov ◽  
Yu. E. Kalinin ◽  
S. N. Starostenko ◽  
A. B. Granovskii
Keyword(s):  
Magnetic Permeability ◽  
High Frequency

scholarly journals VLA Polarization Observation of the Radio Arc at 15 Ghz

1989 ◽  
Vol 136 ◽  
pp. 269-274 ◽  
Author(s):  
M. Inoue ◽  
E. Fomalont ◽  
M. Tsuboi ◽  
F. Yusef-Zadeh ◽  
M. Morris ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
High Spatial Resolution ◽  
Intrinsic Polarization ◽  
Linear Feature ◽  
Field System ◽  
Polarization Observation ◽  
Field Systems ◽  
Relativistic Particles ◽  
Accelerated Particles

Polarization measurements of the radio Arc were made with the VLA at 15 GHz. High frequency polarimetry made with high spatial resolution minimizes Faraday depolarization and reveals polarized filaments which correspond to the predominant filaments of the radio Arc. We notice a peculiar linear feature in the polarization map (“thorns”) which suggests the presence of a second magnetic field system. The total intensity maps show no evidence for an interaction between the two field systems, so the thorns may be foreground magnetized structures. However, if the two magnetic field systems do interact, it would allow a model in which the acceleration of relativistic particles takes place at their intersection. The accelerated particles would flow toward both ends of the radio Arc, and account for the intrinsic polarization observed along the entire length of the system. Thermal electrons responsible for the Faraday depolarization occuring at longer wavelengths may be supplied by the interaction of the streams of relativistic particles with relatively dense, ambient thermal clouds.

An improved adaptive stochastic resonance with general scale transformation to extract high-frequency characteristics in strong noise

2018 ◽  
Vol 32 (15) ◽  
pp. 1850185 ◽  
Author(s):  
Dawen Huang ◽  
Jianhua Yang ◽  
Jingling Zhang ◽  
Houguang Liu
Keyword(s):  
Stochastic Resonance ◽  
High Frequency ◽  
Signal To Noise Ratio ◽  
Scale Transformation ◽  
Weak Signal ◽  
Signal Features ◽  
Signal Characteristics ◽  
Periodic Signals ◽  
Sr Method ◽  
General Scale

The idea of general scale transformation is introduced in detail. Based on this idea, an improved adaptive stochastic resonance (SR) method is proposed to extract weak signal features. Different periodic signals are considered to verify the proposed method. Compared with the normalized scale transformation, the output signal-to-noise ratio (SNR) of the proposed method is increased to a greater extent. Further, the influences of some key parameters on the responses of the two methods are discussed minutely. Results show that the improved adaptive SR method with general scale transformation is obviously superior to the traditional normalized scale transformation that is used in the former literatures. For different noise intensities and time scales, the proposed approach can always obtain the optimal response of SR to enhance the weak signal characteristics.

Electronic tuning of magnetic permeability in Co2Z hexaferrite toward high frequency electromagnetic device miniaturization

2011 ◽  
Vol 98 (20) ◽  
pp. 202502 ◽  
Author(s):  
Yajie Chen ◽  
Andrew Daigle ◽  
Trifon Fitchorov ◽  
Bolin Hu ◽  
Michael Geiler ◽  
...  
Keyword(s):  
Magnetic Permeability ◽  
High Frequency ◽  
Electromagnetic Device ◽  
Electronic Tuning ◽  
Device Miniaturization
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