A device of detecting magnetic characteristic change for a long material includes: an exciting coil into which the long material is inserted and which magnetizes the long material in a longitudinal direction; a detecting coil into which the long material is inserted and which detects a magnetic flux generated in the long material due to magnetization by the exciting coil; and a yoke member which has a first opening portion which is positioned on one side of the long material in the longitudinal direction and into which the long material is inserted and a second opening portion which is positioned on the other side of the long material in the longitudinal direction and into which the long material is inserted, and has a shape which is substantially axially symmetrical about an axis passing the first opening portion and the second opening portion, and the exciting coil and the detecting coil are surrounded by the yoke member, the first opening portion, and the second opening portion.

A measurement apparatus includes: a memory; and a processor coupled to the memory and configured to: acquire, for each of two samples which are objects made of a same material, have different sizes, and have similar shapes, magnetization curve data measured for the sample and a shape parameter including a dimension of the sample; calculate magnetization of an inner part of each of the samples based on the acquired magnetization curve data and shape parameter of the sample by using a model representing magnetization of the object by separating the magnetization of the object into a magnetization component of a surface part and a magnetization component of an inner part of the object in accordance with a volume ratio between the surface part and the inner part of the object; and output the calculated result.

A magnetic-field-applying bias film exhibiting resistance to a high magnetic field has an exchange-coupled film including a permanent magnet layer and an antiferromagnetic layer stacked on the permanent magnet layer. The antiferromagnetic layer includes an X(Cr—Mn) layer containing Cr, Mn, and one or two or more elements selected from the group consisting of platinum-group elements and Ni. The X(Cr—Mn) layer has a first region relatively near to the permanent magnet layer and a second region relatively distant from the permanent magnet layer. Mn content in the first region is higher than Mn content in the second region.

A test and measurement instrument for determining magnetic core losses of a device under test during in circuit operation. The test and measurement instrument receives a primary current signal from a primary winding of a device under test and receives a primary voltage signal measured across a magnetic core of the device under test. Based on the primary electric current signal and the primary voltage signal, the test and measurement instrument determines a magnetic loss of the device under test. In some examples, the test and measurement instrument can use primary and secondary voltage and current inputs to determine the magnetic loss of the device under test. The magnetic loss of the device under test can be displayed on a display of the test and measurement instrument. The magnetic loss can include a total magnetic loss, a hysteresis loss, a copper loss, and/or other losses.

A test and measurement instrument for determining magnetic core losses of a device under test during in circuit operation. The test and measurement instrument receives a primary current signal from a primary winding of a device under test and receives a primary voltage signal measured across a magnetic core of the device under test. Based on the primary electric current signal and the primary voltage signal, the test and measurement instrument determines a magnetic loss of the device under test. In some examples, the test and measurement instrument can use primary and secondary voltage and current inputs to determine the magnetic loss of the device under test. The magnetic loss of the device under test can be displayed on a display of the test and measurement instrument. The magnetic loss can include a total magnetic loss, a hysteresis loss, a copper loss, and/or other losses.

A hysteresis effect-based Field Free Point-Magnetic Particle Imaging (FFP-MPI) method includes the following steps: acquiring a hysteresis loop model of Superparamagnetic Iron Oxide Nanoparticles (SPIOs); calculating to obtain a Point Spread Function (PSF) of the SPIOs on the basis of a sinusoidal excitation magnetic field and the hysteresis loop model of the SPIOs; acquiring an original reconstructed image of FFP-MPI on the basis an FFP moving track and a voltage signal; performing deconvolution on the original image with respect to the PSF considering an hysteresis effect, so as to obtain a final reconstructed image; the artifacts and phase errors of image reconstruction caused by the hysteresis effect of the SPIOs with large particle sizes are reduced, the deficiency in reconstruction by the traditional reconstruction method that ignores the hysteresis effect is overcome, the reconstruction speed and the resolution are greatly improved, and the application range of the SPIOs is expanded.

A hysteresis effect-based Field Free Point-Magnetic Particle Imaging (FFP-MPI) method includes the following steps: acquiring a hysteresis loop model of Superparamagnetic Iron Oxide Nanoparticles (SPIOs); calculating to obtain a Point Spread Function (PSF) of the SPIOs on the basis of a sinusoidal excitation magnetic field and the hysteresis loop model of the SPIOs; acquiring an original reconstructed image of FFP-MPI on the basis an FFP moving track and a voltage signal; performing deconvolution on the original image with respect to the PSF considering an hysteresis effect, so as to obtain a final reconstructed image; the artifacts and phase errors of image reconstruction caused by the hysteresis effect of the SPIOs with large particle sizes are reduced, the deficiency in reconstruction by the traditional reconstruction method that ignores the hysteresis effect is overcome, the reconstruction speed and the resolution are greatly improved, and the application range of the SPIOs is expanded.

A measurement apparatus acquires actually-measured closed magnetic path curve data, actually-measured open magnetic path curve data, and a surface magnetic property value; calculates, for each divided region obtained by sectioning and dividing the permanent magnet, by using a function including a parameter that determines distribution of magnetic property of the permanent magnet, a magnetic property value of the divided region based on an internal magnetic property value extracted from the actually-measured closed magnetic path curve data and the surface magnetic property value; calculates estimated open magnetic path curve data indicating a magnetization curve of the permanent magnet, based on a magnetic property value and the actually-measured closed magnetic path curve data; changes a value of the parameter to minimize a magnetization difference between the actually-measured open magnetic path curve data and the estimated open magnetic path curve data; and outputs a magnetic property value of each of the divided regions.

A tension measuring method installs a reel having a cylindrical coil forming part on a cable to be measured, forms a coil by winding a conductor around the coil forming part, measures a magnetic hysteresis loop of the cable by supplying a current to the coil to generate a magnetic field, and computes a tension of the cable using a parameter determined from the hysteresis loop. A magnetic field sensor and a magnetic flux sensor are provided inside a through hole in the coil forming part, and the cable is positioned inside the through hole. The magnetic field is varied so that the hysteresis loop includes a near-saturation magnetization region, to measure the hysteresis loop using the sensors. The parameter is selected from a magnetic flux or a magnetic flux density, a remanent magnetization, a coercivity, a magnetic permeability, and a hysteresis loss in the near-saturation magnetization region.

A tension measuring method installs a reel having a cylindrical coil forming part on a cable to be measured, forms a coil by winding a conductor around the coil forming part, measures a magnetic hysteresis loop of the cable by supplying a current to the coil to generate a magnetic field, and computes a tension of the cable using a parameter determined from the hysteresis loop. A magnetic field sensor and a magnetic flux sensor are provided inside a through hole in the coil forming part, and the cable is positioned inside the through hole. The magnetic field is varied so that the hysteresis loop includes a near-saturation magnetization region, to measure the hysteresis loop using the sensors. The parameter is selected from a magnetic flux or a magnetic flux density, a remanent magnetization, a coercivity, a magnetic permeability, and a hysteresis loss in the near-saturation magnetization region.