547 results about "Ferromagnetism" patented technology

The invention provides a chemical restoration method for treating heavy metal-polluted terrain soil by ferromagnetic artificial nucleuses. In a ferromagnetic artificial nucleus soil restoration method, the ferromagnetic artificial nucleuses are applied to heavy metal-polluted soil; soil above a heavy metal pollution depth is overturned by cultivation equipment to uniformly mix with the ferromagnetic artificial nucleuses; and after heavy metal can be dispersed from the soil to the artificial nucleuses by a period of time, the soil containing the artificial nucleuses is overturned by using the cultivation equipment to increase the change of the artificial nucleuses contacting with other soil. After the soil overturning procedure is repeated by multiple times, the cultivation equipment provided with magnets can be used for separating the ferromagnetic artificial nucleuses, absorbed with the heavy metal, from the polluted soil; and the content of the heavy metal of the polluted soil is reduced due to shifting-out of the ferromagnetic artificial nucleuses, so that the purpose of soil restoration is gradually achieved.

The invention relates to the field of electromagnetic nondestructive testing, in particular to a curved surface self-adaptive eddy current testing probe, a nondestructive flaw detector and a testing method. The eddy current detection probe comprises a magnetic core bundle, an excitation coil and an induction coil. Wherein the magnetic core bundle is formed by densely arranging a plurality of ferromagnetic magnetic needles; and the excitation coil and the induction coil radially limit the magnetic core bundle. The excitation coil is wound on one end of the magnetic core bundle away from the detection surface and is used for connecting an adjustable power supply. The exciting coil generates an alternating magnetic field for detection in a target area by using the adjustable power supply, and magnetizes the magnetic core bundle by using the adjustable power supply, so that the detection surface of the eddy current detection probe is tightly adsorbed with the target area on the surface of a detected object. And the induction coil is wound at one end, close to the detection surface, in the magnetic core bundle and is used for inducing a signal generated by a detected object in the detection process. According to the invention, the problem that the existing electromagnetic nondestructive testing probe cannot be attached to various complex curved surfaces to cause signal attenuation and influence the measurement precision is solved.

The invention relates to the field of metal material nondestructive testing, and provides a non-ferromagnetic metal material surface profile reconstruction method based on a rotating alternating current electromagnetic field, which comprises the following steps of: determining a detection point array of a detection area, acquiring a vertical magnetic field signal z of the detection area by adopting a TMR magnetic sensing chip, and forming an initial Bz numerical matrix Bz0; performing bilateral filtering; obtaining a Bz numerical matrix Bz2 after morphological processing; obtaining a weighted Bz numerical matrix Bz3; a positive value matrix is formed, binarization processing is conducted on the positive value matrix, and a key numerical value matrix area Tkey containing crack related feature points is formed; calculating the center-of-mass coordinates of the disconnected independent areas, which are called nodes; on the basis of an improved Boruvka algorithm, new edge weight design is carried out on connecting edges between nodes, and a generated minimum spanning tree is effective representation of the surface profile of the bifurcated crack of the metal part.

The invention discloses a preparation process of special-shaped zinc powder, which comprises the following steps: cleaning spherical powder, pressing into a thin pancake, coating a ferromagnetic material part on the surface of the spherical zinc powder through magnetron sputtering, and then carrying out oriented shearing ball milling by using a high-energy ball mill and an external magnetic field, so as to obtain the special-shaped zinc powder. And the processed special-shaped zinc powder is graded through magnetic separation and a special-shaped screen to prepare the non-magnetic or weakly-magnetic 1-5 [mu] m screened special-shaped zinc powder. By means of the technology, the special-shaped zinc powder which is appropriate in sphericity degree and high in one-time ball milling qualification rate can be efficiently prepared and used for production of zinc-rich paint.

The invention discloses a method and a device for detecting and positioning an underground pipeline containing a ferromagnetic material. According to the invention, the fluxgate sensors and the position and attitude sensors are installed on the support frame, and the support frame is driven to rotate, so that rapid magnetic scanning measurement of the underground pipeline is realized, and the trend, the horizontal position and the depth of the pipeline are estimated. According to the invention, the efficiency is greatly improved by adopting a rotary scanning strategy, the problem of uneven or muddy ground is avoided, and the method is suitable for detecting a ferromagnetic target with a slender structure; the direction and depth of the pipeline are estimated by using the coordinates of the extreme points of the magnetic field, and the positions of ferromagnetic targets which are non-uniformly distributed along any straight line can be estimated; the method does not need an accurate magnetic field value, is suitable for a complex environment with strong interference, is short in estimation time, and supports real-time positioning of the pipeline; and the corresponding pipeline depth below each measurement node is estimated by using the measurement data of the plurality of measurement nodes at different heights, so that the method can be applied even if the pipeline is not horizontally buried.

The invention discloses a ferromagnetic material internal defect leakage magnetic field increasing method based on alternating current and direct current composite magnetization, which comprises the following steps of: fixing a workpiece at the center of a composite exciting coil, and synchronously applying direct current and high-frequency alternating current; after pure direct current magnetization is saturated, current is locked, and a basic leakage magnetic field is established; the surface magnetic conductivity is dynamically reduced by overlapping alternating current, and the magnetic shielding effect is weakened; a leakage magnetic field signal is scanned and collected through a differential Hall sensor array, and background magnetic field deduction, peak value comparison and adaptive filtering processing are carried out; and determining an optimal magnetization parameter combination by adopting a gradient descent method and Bayesian optimization. The system is integrated with a composite excitation coil and a signal conditioning unit, so that synchronous excitation, signal acquisition and real-time analysis are realized. The leakage magnetic field signal at the deep defect is enhanced through alternating-current and direct-current composite magnetization, the problem of signal weakening caused by traditional direct-current saturation is solved, the defect detection sensitivity and efficiency are improved, and the method is suitable for non-destructive detection scenes of ferromagnetic materials.

A cover mat includes first and second layers each having an upper surface and a bottom surface and each comprising a foam material, the second layer attached to the first layer, the second layer configured to be supported by a support surface that is separate from the cover mat, wherein a preformed relief extends into at least one of the first layer and the second layer, and a magnet located within the preformed relief and between the first layer and the second layer such that the magnet is completely encapsulated between the first layer and the second layer, and wherein the magnet is configured to secure a ferromagnetic article to the cover mat.

A method for fabricating an optoelectronic arrangement is described, comprising the following steps: - Providing a carrier (1) with a top surface (1a) and a bottom surface (1b), - Forming a plurality of contact pads (2) on the carrier (1) on the upper surface (1a), wherein each contact pad (2) is free of ferromagnetic materials, - Forming a shield (3) on the carrier (1), wherein the shield (3) at least partially surrounds each contact pad (2) in the lateral direction (L) and comprises a first ferromagnetic material, - Providing a plurality of optoelectronic components (4), each component comprising a second ferromagnetic material on a side facing the upper surface (1a) of the support (1), - Providing a magnet (5) on the lower surface (1b) of the support (1), wherein the magnet exerts a magnetic force (F), - Bringing the majority of optoelectronic components (4) closer to the upper surface (1a) and - Attaching the majority of optoelectronic components (4) to the carrier (1) on the upper surface (1a). The optoelectronic components (4) may, for example, be micro-LEDs.

The invention relates to a magnetic field sensitivity matrix rapid acquisition method based on a magnetic sensor array, and the method comprises the steps: introducing a virtual coil to replace a magnetic sensor in simulation, carrying out the calculation to obtain a virtual coil voltage sensitivity matrix, and rapidly obtaining a magnetic field sensitivity matrix through the relation between the voltage of the virtual coil and the magnetic flux density. And the magnetic field sensitivity matrix is used for imaging the defect position and size of the non-ferromagnetic metal plate by the magnetic sensor.

The invention provides a nano-plastic detection device and method based on a magnetic adsorption-thermal cracking mass spectrometry technology, and solves the technical problem that the variety, content and physicochemical properties of nano-plastic in a water matrix are difficult to rapidly and accurately capture in the prior art. The pyrolysis device comprises a closed heating cavity, a resistance wire is wound on the closed heating cavity, the closed heating cavity is communicated with a carrier gas inlet pipe, a water vapor outlet pipe and a pyrolysis gas outlet pipe, and a sample groove is formed in the closed heating cavity; the sample introduction device comprises a sample introduction pipeline, and the sample introduction pipeline penetrates into the closed heating cavity in a sealed manner and is communicated with the sample groove; the groove bottom of the sample groove is a filter layer, the filter layer comprises a filter membrane layer, the filter membrane layer is connected to a ferromagnetic metal sheet, the aperture of filter holes of the filter membrane layer is smaller than the particle size of the nano-plastic, the heat-resistant temperature of the filter membrane layer is higher than the boiling point of the nano-plastic, and the ferromagnetic metal sheet is provided with a filtrate channel; the suction filtration device comprises a suction filtration head; the suction filtration head is communicated with the sample groove through a filter layer; the method can be widely applied to the technical field of nano-plastic pollution detection.

The invention discloses a method for enhancing coalbed methane recovery efficiency by an external magnetic field, which comprises the following steps of: arranging a plurality of electrified coils or magnetic field generators connected with a power supply in a coalbed to generate an alternating magnetic field in the coalbed; cH4 molecules show diamagnetism under the action of a magnetic field, a repulsive effect is generated in a coal seam, and the adsorption effect of CH4 and a coal body is weakened; and on the other hand, as the coal body contains ferromagnetic or paramagnetic minerals, the alternating magnetic field excites the annular eddy current in the coal body through electromagnetic induction so as to generate Joule heat. Therefore, coal matrix expansion and microfracture expansion can be induced by temperature rise of the coal body, the permeability of the coal body is further improved, and more channels are provided for CH4 desorption and flowing; the clean, efficient and environment-friendly coal bed gas exploitation method is provided on the basis of superposition of multiple production increasing mechanisms, and a new technical approach is provided for exploration and development of unconventional oil and gas resources.

The invention relates to a seabed trapezoidal foldable electromagnetic coil device, which belongs to the technical field of ocean electromagnetic detection and comprises a main bearing beam, an expandable transmitting coil assembly, a receiving coil assembly, a transmission connecting rod, a hinged rotating seat, a sliding connecting seat and a push-pull driving rod. The transmitting coil is of a symmetrically-distributed trapezoidal structure, the receiving coil is in sliding fit with the main bearing beam through the sliding connecting base, the push-pull driving rod is in linkage with the receiving coil to move and the transmitting coil to be unfolded / folded, the device frame is made of a macromolecule non-magnetic material, and the ferromagnetic driving component is arranged in an avoiding mode. Receiving coil plane magnetic field balance is achieved through the non-uniform magnetic field design of the trapezoidal transmitting coil, coil space optimization configuration is completed through a linkage mechanism, folding portability and anti-interference performance of a multi-layer coil are achieved at the same time, direct coupling of a primary field of the transmitting coil to receiving is effectively restrained, the stability and the signal-to-noise ratio of a detection signal are improved, and the detection precision is improved. The method is suitable for complex seabed transient electromagnetic detection scenes carried by AUV / ROV.

The utility model provides a tube plate welding seam magnetic defect detector, which relates to the technical field of seam magnetic defect detectors and comprises a magnetizing device, a first mounting rack is fixedly connected to the bottom of the magnetizing device close to the left side, and a connecting shaft is rotatably connected between the inner surface walls of the first mounting rack. A second probe is fixedly connected to the outer surface of the connecting shaft, a second rotating shaft is rotationally connected to the position, close to the bottom, of the inner surface wall of the second probe, second rolling wheels are fixedly connected to the positions, close to the two ends, of the outer surface of the second rotating shaft, and a first probe is fixedly connected to the position, close to the right side, of the bottom of the magnetizing device. According to the device, the angle and the position of the second probe are flexibly adjusted, so that the device can quickly and accurately identify and display various defects on the surface and the near surface of a ferromagnetic material in a tube plate welding seam, the operation is simple, time and labor are saved, and the efficiency of magnetic powder detection can be effectively improved.

The invention relates to the technical field of nondestructive testing, and particularly discloses a non-ferromagnetic thin plate full-wall-thickness defect detection method and system, and the method comprises the steps: applying a rotating electromagnetic field generated by excitation of two paths of multi-frequency signals with orthogonal phases, and synchronously collecting spatial magnetic field response data to form original response data; the method comprises the following steps: converting a time domain signal of each spatial point into a two-dimensional time-frequency spectrum, organizing into a time-frequency-space three-dimensional joint data volume, performing high-order decomposition on the data volume to separate out a plurality of independent signal components, and calculating a spatial statistical variable coefficient and a frequency maximum centroid offset of the independent signal components to obtain a time-frequency-space three-dimensional joint data volume; a target signal component representing defect disturbance is screened out, the defect depth is calculated based on the time feature of the target component, the defect two-dimensional morphology is reconstructed by combining the space feature of the target component, and the defect three-dimensional model is generated by fusing the defect depth and the defect two-dimensional morphology through improved inverse distance weighted interpolation and curved surface smoothing; according to the invention, detection and three-dimensional shape reconstruction of defects with different depths and different orientations in the thin plate are realized.

The invention discloses a real-time video positioning method based on ferromagnetic substance magnetic field signal three-dimensional imaging simulation, and relates to the field of ferromagnetic substance detection in a medical scene nuclear magnetic resonance room, and the method comprises the steps: carrying out the segmentation fitting of a magnetic field gradient through employing a B-spline basis function; performing omni-directional calibration on the array through a rotating platform, and establishing a nonlinear mapping matrix of sensor output and real magnetic field intensity; extracting target shape features; performing optical flow estimation on the video frame, and compensating magnetic field measurement delay caused by target motion; establishing an incidence matrix of the target state vector and the measured value; reconstructing the three-dimensional space distribution of the ferromagnetic substance through an inversion method based on a perspective transformation model; and fusing the three-dimensional imaging result with the real-time video. Magnetic field measurement delay caused by target motion is compensated by performing optical flow estimation on a video frame, and a state estimation convergence speed is improved by estimating a multi-mode parallel state.

Removable straw cover securing mechanisms, beverage containers with removable straw cover securing mechanisms, and methods of manufacturing, testing, and using the same are provided herein, among things. The removable straw cover includes a magnetic or ferromagnetic component that can be mateably engaged with a corresponding magnetic or ferromagnetic element on a lid to securely secure the removable straw cover to the lid. This magnetic interaction forms a secure yet easily detachable bond, allowing for convenient use.

The invention discloses a ferromagnetic material defect identification method and system based on magnetic gradient tensor measurement, and relates to the technical field of nondestructive testing, and the method comprises the following steps: acquiring magnetic gradient tensor data of a to-be-tested piece; calculating a total horizontal derivative based on the magnetic gradient tensor data; calculating a z-direction partial derivative of each component based on the total horizontal derivative and calculating a vertical derivative based on the magnetic gradient tensor data; and identifying a defect boundary by using the magnetic gradient tensor fusion derivative detector and the magnetic gradient tensor anti-noise boundary detector, and outputting a defect profile diagram. According to the invention, the MGTFDED and MGTNRED detectors specially designed for industrial defect detection scenes are provided for the first time, and the problem that a geophysical method is not suitable for direct transplantation is solved. According to the method, the edges of various defects from surface cracks to deep buried holes and the like can be identified with high precision, and the accuracy, noise resistance and intelligent level of detection are remarkably improved.

The invention belongs to the technical field of non-magnetic material nondestructive testing, and discloses a non-ferromagnetic material thickness and conductivity synchronous measurement method based on eddy current phase characteristics, and the method comprises the specific steps: S1, estimating the conductivity and thickness range of a to-be-tested piece based on data such as a product specification or an industrial standard; s2, determining excitation frequency according to a frequency selection criterion (high frequency enables the skin effect depth to be smaller than 1 / 3 of the thickness, and low frequency enables the skin effect depth to be larger than two times of the thickness of the sample); s3, an eddy current method is adopted to obtain the impedance variable quantity phase of the to-be-measured non-ferromagnetic material; and S4, substituting the phases into corresponding simplified model formulas respectively, and obtaining the conductivity and the thickness at the same time. Aiming at the problems of multiple calibration, blindness in excitation frequency selection, low single-parameter measurement efficiency and the like in conductivity or thickness measurement by an existing eddy current method, double-parameter output of single measurement is realized, multiple calibration and inversion calculation are not needed, the calculation is simple, rapid and accurate, the hardware cost is low, and the applicability is wide.

An electromagnetic reciprocating pump (1) and an alcohol tester. The electromagnetic reciprocating pump (1) comprises a driving device (10) and a pump body (20). The pump body (20) comprises a flexible housing (22), an accommodating cavity (C3), and a channel (213) in communication with the accommodating cavity (C3). The driving device (10) comprises a cylinder (111), a coil (112), a magnet (121), a first ferromagnetic element (113) and a second ferromagnetic element (114); the coil (112) generates magnetic fields in different directions by changing the current direction so as to drive the magnet (121) in the cylinder (111) to move back and forth in a motion direction; the first ferromagnetic element (113) and the second ferromagnetic element (114) are spaced apart at the front end and rear end in the motion direction of the magnet; the first ferromagnetic element (113) and the second ferromagnetic element (114) can attract the magnet (121), and when the magnet (121) moves to one end and is attracted by one of the first ferromagnetic element (113) and the second ferromagnetic element (114), the magnet (121) is kept at the position; the magnet (121) is used for driving the flexible housing (22) to deform so as to change the volume of the accommodating cavity (C3) to achieve fluid intake and discharge. According to the electromagnetic reciprocating pump (1) and the alcohol tester, different states of the pump body can be maintained, and the structure is simple.

The invention discloses a nondestructive testing and noise filtering method, system and device and a storage device. The nondestructive testing and noise filtering method comprises the steps that first detection data obtained when a diamond NV color center is subjected to magnetic flux leakage detection are collected; wherein the first detection data at least comprises feedback fluorescence and a scanning position corresponding to the feedback fluorescence; converting the feedback fluorescence into a fluorescence electric signal, and performing noise reduction processing on the fluorescence electric signal by using a first adaptive denoising algorithm; and calculating and analyzing the signal after noise reduction processing to obtain magnetic field information. According to the method, the leakage magnetic field of the ferromagnetic material defect is detected through the high-sensitivity NV color center magnetic sensor, and the self-developed adaptive wavelet threshold denoising method is combined, so that the environmental noise is effectively inhibited, and the weak magnetic field signal is accurately extracted; a quantum precision measurement platform is built based on the NV color center magnetic sensor, and detection of extremely tiny cracks can be achieved; the microwave frequency is supported to dynamically adjust the sensitivity so as to adapt to different detection requirements, and the detection precision and adaptability in a complex industrial environment are remarkably improved.

The utility model discloses a positioning mechanism for leather punching equipment, and relates to the technical field of leather processing, and the positioning mechanism comprises a ferromagnetic base plate which is used for supporting materials; the pressing plate and the supporting plate are parallel to each other, an electromagnet is fixedly connected to the supporting plate, and the electromagnet is used for fixing the supporting plate and the ferromagnetic substrate in a magnetic attraction mode; the pressing plate is in sliding connection with the supporting plate through an elastic assembly, and the elastic assembly exerts downward pressure on the pressing plate to press materials. According to the positioning mechanism for the leather punching equipment, the pressing plate and the supporting plate are arranged, the supporting plate is fixed to the ferromagnetic base plate through the electromagnet, pressure is applied to the pressing plate through the elastic assembly to press and fix the edge of leather, and positioning is convenient and firm.

A composite electromagnetic wave-absorbing material and preparation method therefor are provided. The composite electromagnetic wave-absorbing material includes following raw materials: magnetite powder, nickel powder, copper powder, samarium oxide, gadolinium oxide, cerium oxide, carbon black powder, graphite powder, epoxy resin, barium titanate powder, antioxidant, curing agent, diluent and leveling agent. Ferrite wave-absorbing materials are used as matrixes to be compounded with nickel powder, copper powder, graphite powder, carbon black and barium titanate, and doped with mixed rare earth oxides through combination of samarium oxide, gadolinium oxide and cerium oxide to thereby obtain the composite electromagnetic wave-absorbing material which combines magnetic loss characteristics of magnetite powder, ferromagnetic behavior of nickel powder and conductivity of copper powder, helping to achieve good electromagnetic wave-absorbing performance. By introducing graphite powder, carbon black powder and barium titanate powder as fillers and doping rare earth, wave-absorbing characteristics of the composite electromagnetic wave-absorbing material are improved.

The invention relates to the technical field of magnetic suspension compressor assembly, and particularly discloses a magnetic pollution source prevention and control optimization method in a magnetic suspension compressor assembly process, which comprises the following steps: in a pretreatment stage of magnetic suspension compressor assembly, dynamically optimizing thermal cycle parameters in a low-temperature environment by adopting a self-adaptive genetic algorithm; ferromagnetic impurities hidden in microdefects of the compressor component are accurately induced to be released in advance; carrying out feature extraction and pattern recognition on the released impurity signals in combination with wavelet packet transformation and a neural network algorithm; according to the method, a low-temperature thermal cycle process optimized by a self-adaptive genetic algorithm is constructed in the pre-assembly treatment stage, ferromagnetic impurities hidden in microcracks are accurately induced to be released in advance, and accurate removal of the impurities before entering the assembly link is realized by combining wavelet packet transformation and targeted pulse demagnetization driven by a neural network; the limitation that impurities in the microdefects cannot be touched by a traditional cleaning and demagnetizing method is broken through, and the hidden danger of magnetic pollution which cannot be found by initial detection is eliminated from the source.

The invention discloses a solvent recycling device for a PU synthetic leather wet-process production line and a use method of the solvent recycling device, and relates to the technical field of mechanical engineering. Comprising a liquid inlet pipe and further comprises a feeding component, the top of the feeding component is fixedly connected with the top of the liquid inlet pipe, the feeding component comprises a pre-separation assembly, the top of the pre-separation assembly is fixedly connected with the bottom of the liquid inlet pipe, and the inner wall of the pre-separation assembly is slidably connected with a magnetic separation assembly; according to the recycling device, a radial magnetic field is generated through permanent magnet blocks annularly arrayed on the outer wall of a conical block, ferromagnetic impurities are efficiently adsorbed and prevented from entering a follow-up filtering assembly to cause blockage, non-stop maintenance is supported through the sliding design of a pull rod and a limiting ring, and the practicability is high. Adsorbed impurities can be rapidly cleaned by pulling the magnetic separation assembly, the maintenance time is shortened, and the solvent recycling device achieves the purpose of the solvent recycling device for the PU synthetic leather wet production line.

The present invention discloses an electromagnetic heating smoking device and an electromagnetic heating system, which relate to the field of electromagnetic heating technology. The electromagnetic heating smoking device includes a shell, an electromagnetic coil, a parameter acquisition module, a drive device, and a control module. When alternating current is applied to the electromagnetic coil, a changing alternating magnetic field is generated. The parameter acquisition module acquires the magnetic field strength in the heating chamber. When the magnetic field strength is less than a preset magnetic field strength, the control module controls the electromagnetic coil to move in the shell through the drive device until the new magnetic field strength reaches the preset magnetic field strength. It can be seen that the present application controls the electromagnetic coil to move in the shell through the drive device when the magnetic field strength at the position where the ferromagnetic element in the cigarette is located is less than the preset magnetic field strength, until the new magnetic field strength reaches the preset magnetic field strength. At this time, the ferromagnetic element in the cigarette is at the center of the alternating magnetic field, so as to achieve the maximum heating efficiency of the electromagnetic heating smoking device and improve the user's experience satisfaction.

The invention relates to a manufacturing method of a magnetic sensor. The magnetic sensor includes at least one MR element and at least one magnetic field generator. The at least one MR element includes a magnetization-fixed layer and a free layer. The at least one magnetic field generating body includes a ferromagnetic part and an antiferromagnetic part that is exchange-coupled to the ferromagnetic part. A method for manufacturing a magnetic sensor includes a step of forming at least one MR element, and a step of forming at least one magnetic field generator. The step of forming the at least one magnetic field generating body includes: a step of forming at least one initial magnetic field generating body including an initial ferromagnetic part and an antiferromagnetic part that later become a ferromagnetic part; and a step for fixing the direction of magnetization of the initial ferromagnetic part using the laser and the external magnetic field so that the initial ferromagnetic part becomes a ferromagnetic part.

The application discloses a multi-directional excitation magneto-optical image registration method under hybrid driving, and the method comprises the following steps: collecting the defect magnetic field distribution information of the surface of a ferromagnetic material under multi-directional excitation through a magneto-optical imaging device to obtain a reference image and a floating image; extracting the defect contour of the two images according to a gradient operator; performing spatial transformation on the defect contour of the floating image, and then performing or operation and morphological closing operation on the defect contour of the floating image and the defect contour of the reference image to obtain a defect contour map with closed shape; obtaining the magnetic leakage field distribution map of the defect contour map through defect magnetic leakage field model forward modeling; calculating the similarity measure of the reference image and the magnetic leakage field distribution map generated by the model; and finally continuously updating the spatial transformation parameters through an optimization search algorithm, and the registration is successful when the similarity measure reaches the maximum.

Provided is a magnetic recording medium comprising a non-magnetic support and a magnetic layer containing ferromagnetic powder, and further comprising a non-magnetic layer containing non-magnetic powder between the non-magnetic support and the magnetic layer. The average pore diameter of the magnetic layer and the non-magnetic layer is 30.0 nm or less, and the standard deviation of the pore diameter distribution of the magnetic layer and the non-magnetic layer is 30.0 nm or less.

The invention relates to a magnetic sensor. This magnetic sensor is provided with: at least one MR element; a ferromagnetic layer configured to overlap the at least one MR element when viewed from the first direction; insulating layers disposed on both sides of the at least one MR element in the second direction; and an antiferromagnetic layer disposed over the at least one MR element, the ferromagnetic layer, and the insulating layer. The antiferromagnetic layer includes an antiferromagnetic portion facing the ferromagnetic layer, and a non-facing portion facing the at least one MR element and the insulating layer but not facing the ferromagnetic layer. There is no magnetic layer between the at least one MR element and the antiferromagnetic layer.

The invention discloses a ferromagnetic material displacement measurement method and device based on PWM waves and a phase method. The method comprises the steps that two paths of same-frequency PWM square wave signals are generated; applying the excitation signal to the electromagnetic induction probe, and based on the relative displacement between the electromagnetic induction probe and the ferromagnetic material, obtaining an induction signal which is output by the electromagnetic induction probe and whose phase changes with the relative displacement; converting the induction signal into a third PWM square wave signal, wherein the phase of the third PWM square wave signal is related to the phase of the induction signal; performing logic AND operation on the third PWM square wave signal and a reference signal to generate a pulse signal; and filtering the pulse signal to obtain a displacement measurement result proportional to the relative displacement. The single-chip microcomputer is adopted to generate high-frequency PWM waves, the phase method and digital logic processing are combined, magnetic field interference and signal drifting in ferromagnetic material measurement are effectively restrained, high precision and high dynamic response are guaranteed, and meanwhile system complexity and cost are remarkably reduced.