53 results about "Residual magnetization" patented technology

The invention belongs to the technical field of geophysics, and particularly discloses a magnetization intensity vector sparse inversion method under a strong residual magnetism condition. The method comprises the following steps: firstly, subdividing an underground space, and simulating an underground magnetic anomalous body; obtaining a sensitivity matrix according to partial derivatives of observed magnetic anomaly values of the magnetic anomaly body in each unit magnetization direction, and constructing a total objective function of magnetization intensity vector inversion based on the sensitivity matrix; taking magnetization intensity amplitude as a parameter to introduce sparse constraint for the total objective function; converting the total target function into a standard L2 regularization form, and calculating a sensitivity matrix by using a singular value analysis method so as to obtain target parameters of the total target function; and finally, obtaining three components of the magnetization intensity vector from the target parameters, and further solving the magnetization intensity amplitude and the total magnetization direction. According to the scheme, the magnetization intensity inversion precision under the influence of strong residual magnetization is effectively improved.

The invention discloses a method for preparing (SmxY1-x) Co5 rare earth magnetic particles with high magnetic properties by a chemical method, and belongs to the field of rare earth magnetic materials. The invention particularly relates to a novel technology for preparing (SmxY1-x) Co5 ternary alloy magnetic powder with high magnetic properties by combining chemical liquid phase synthesis with calcium reduction reaction. A Sm (OH) 3 / Y (OH) 3 / Co (OH) 2 (at) Ca (OH) 2 crystalline state mixed precursor prepared by chemical coprecipitation and a hydrothermal reaction is uniformly subjected to a complete calcium reduction reaction with a certain amount of metal calcium particles, KCl and CaCl2 diffusion media in an argon atmosphere, and the magnetic powder is prepared. The saturation magnetization intensity and the residual magnetization intensity of the magnetic powder are improved by doping the yttrium element, but the coercive force of the magnetic powder is slightly reduced, and the method provides a new thought for preparing high-performance rare earth magnetic particles.

[Object] To provide a Peltier element with an ultra-low thermal resistance heat flux sensor that is capable of detecting heat flow passing through the Peltier element at high speed and has negligible thermal resistance.[Solving Means] It has a structure in which an anomalous Nernst heat flux sensor 20 is formed directly on one or both of an upper part and a lower part of an insulating board that forms a Peltier element 10. The present invention is favorably characterized in that each fine line (22a) of a thermoelectric generator is formed of a magnetic material having residual magnetization even in absence of an external magnetic field and is magnetized in a direction orthogonal to a length direction of the fine line, and each fine line (23a) of a connector is formed of a ferromagnetic material that is magnetized in a direction opposite to a direction in which each fine line (22a) is magnetized, a magnetic material having a Nernst coefficient with an opposite sign to that of each fine line (22a), or a non-magnetic material.

The utility model discloses a pipeline stress internal detection probe which is characterized in that the pipeline stress internal detection probe comprises a pair of L-shaped magnetic cores, two excitation coils are respectively wound on the pair of L-shaped magnetic cores along the same direction, the excitation coils are connected with a driving circuit, and when current i in the same direction is conducted in the excitation coils through the driving circuit, the excitation coils are connected with the driving circuit. A uniform magnetic field area is formed near the distance l between the two magnet exciting coils, and a plurality of magnetic sensors are arranged in the uniform magnetic field area. According to the utility model, the pulse excitation coil is used as a low-frequency pulse magnetic field generating device to magnetize the ferromagnetic pipeline. After the pipeline is magnetized, if an external magnetic field disappears (is reduced to zero), the pipe wall still shows magnetism, and the residual magnetization intensity of the pipe wall at the moment is called residual magnetism. The stress can change the residual magnetization intensity of the ferromagnetic material, so that the internal magnetic conductivity of the material can be changed. Therefore, the residual magnetization is measured through the magnetic sensor integrated in the probe, the stress is represented, and stress detection and analysis are realized.

This application relates to the field of LNG cryogenic pressure vessel welding technology, specifically disclosing a multi-level collaborative control method for magnetic blow in 7Ni steel welding based on a quantified remanent magnetization threshold. Addressing the problems of severe magnetic blow and poor all-position welding stability caused by the high permeability, high coercivity, and difficulty in demagnetizing 7Ni steel, the method uses a remanent magnetization threshold of ≤50Gs to construct a collaborative control system encompassing pre-welding quantitative management, welding polarity and ground wire optimization, welding parameter and sequence constraints, real-time monitoring and automatic demagnetization closed-loop during welding, and post-weld quality verification. This application can effectively suppress all-position magnetic blow, avoiding defects such as arc deviation, incomplete penetration, slag inclusion, and porosity; achieving a first-pass yield of ≥97.5% for the main weld of the LNG storage tank, with a joint impact energy of ≥80J at -196℃ and a hardness of ≤300HV10, meeting cryogenic service specifications and applicable to the industrial welding production of large 7Ni steel LNG storage tanks.

A passive magnetic bearing assembly (10) for a vacuum pump and a vacuum pump having such a bearing are disclosed. The invention relates to a passive magnetic bearing assembly having a plurality of pairs of ring magnets (20, 30) arranged in a stack, one of the ring magnet pairs being arranged on a stator side (4) of the bearing and the other of the ring magnet pairs being arranged on a rotor side (2). The ring magnets are radially magnetized and each rotor ring magnet comprises at least a first harmonic of magnetic inhomogeneity, where the magnetic inhomogeneity is measured as a ratio between a 0-peak variation of remanence [Delta] Bi and an average remanence BR0, the first harmonic of magnetic inhomogeneity being less than 3%.

The invention discloses an oil and gas pipeline internal detection device and method based on the coupling effect of residual magnetism and eddy current, and relates to the technical field of pipeline internal detection. A magnetization node is used to perform saturation magnetization on the pipeline to be detected. When the magnetization node stops magnetizing, the magnetization intensity of the pipeline to be detected decreases from the saturation magnetization intensity to the residual magnetization intensity, and is in a residual magnetization state. An induced eddy current field is generated in the pipeline to be detected by the detection node. The defects of the pipeline to be detected are detected based on the coupled magnetic field formed by the residual magnetization intensity and the induced eddy current field. By magnetizing the pipeline to be detected to the magnetic saturation state, the uneven distribution of the relative magnetic permeability of the pipeline can be eliminated, and the probability of missed detection and false detection of pipeline defects caused by the uneven relative magnetic permeability can be reduced. At the same time, the skin effect of the eddy current detection technology can be suppressed, and the effective detection of internal and external surface defects can be realized. The detection node can obtain the composite signal of residual magnetism and eddy current, and the sensitivity of defect perception is improved, thereby improving the eddy current perception ability based on the residual magnetism effect.

The present application provides a magnetic layer having a coercive force Hc of 2.00 kOe or more and a residual magnetization Mrt per unit area of 2.00 memu / cm2 or more, which is achieved without using a non-magnetic underlayer for promoting in-plane orientation of the magnetic layer and without performing heat deposition 2 The above in-plane magnetization film, in-plane magnetization film multilayer structure, hard bias layer, magnetoresistance effect element, and sputtering target. The in-plane magnetization film has: a preliminary magnetic layer (12A) containing Co, Pt, and a non-magnetic grain boundary material and having a thickness of 1 to 32 nm; and a magnetic layer main portion (12B) formed on the preliminary magnetic layer (12A) and containing Co, Pt, and a non-magnetic oxide, the above non-magnetic grain boundary material of the preliminary magnetic layer (12A) containing at least one of a Zn oxide and a Ta oxide.

A method of producing a SmFeN-based anisotropic magnetic powder is provided, the method including preparing a SmFeN-based anisotropic magnetic powder before dispersing comprising Sm, Fe, W, and N, and dispersing the SmFeN-based anisotropic magnetic powder before dispersing using a resin-coated metal media or a resin-coated ceramic media to obtain a SmFeN-based anisotropic magnetic powder. Also provided is a SmFeN-based anisotropic magnetic powder comprising Sm, Fe, W, and N and having an average particle size of less than 2.5 μm, a residual magnetization or of not less than 130 emu / g, and an oxygen content of not higher than 0.75% by mass.

A method of producing a SmFeN-based anisotropic magnetic powder is provided, the method including preparing a SmFeN-based anisotropic magnetic powder before dispersing comprising Sm, Fe, W, and N, and dispersing the SmFeN-based anisotropic magnetic powder before dispersing using a resin-coated metal media or a resin-coated ceramic media to obtain a SmFeN-based anisotropic magnetic powder. Also provided is a SmFeN-based anisotropic magnetic powder comprising Sm, Fe, W, and N and having an average particle size of less than 2.5 μm, a residual magnetization σr of not less than 130 emu / g, and an oxygen content of not higher than 0.75% by mass.

To provide an R-T-B-based rare earth magnet achieving both residual magnetization and coercive force.SOLUTION: The present invention relates to an R-T-B-based rare earth magnet in which R is a rare earth element, T is Fe and / or Co, and B is boron. R includes Nd. The R-T-B-based rare earth magnet includes a main phase having an R2T14B-type crystal structure and a grain boundary phase present around the main phase. The average grain size of the main phase is 0.1-1.0 μm. The main phase has a core portion and a shell portion present around the core portion. The ratio (concentration of Nd in shell portion / concentration of Nd in core portion) of the concentration of Nd (atom%) in the shell portion and in the core portion of the main phase is 1.654-1.714.SELECTED DRAWING: Figure 2

The application relates to a residual residual magnetism detection method and a detection device, and belongs to an automatic detection method and equipment. The residual residual magnetism detection method comprises the following steps: placing a detection sample on a conveying mechanism, conveying the detection sample to a detection mechanism through the conveying mechanism; under a zero magnetic environment, the detection mechanism detects the residual residual magnetization of the detection sample; after the detection is completed, the detection sample moves to a belt of a sorting mechanism; and according to the detection result of the detection mechanism, the detection sample is classified through the sorting mechanism. The detection method can detect the residual residual magnetization of parts in a production process and / or after processing is completed, can timely monitor and sort, and is high in detection efficiency and accuracy.

The invention provides an online evaluation method and system for the magnetizing inrush current suppression capability of a transformer, and relates to the technical field of power system operation evaluation, and the method comprises the steps: collecting the fracture voltage data of a primary winding of the transformer, and calculating the initial residual magnetism amount of an iron core through a magnetic flux reconstruction algorithm; an improved harmonic superposition method is adopted to decompose a transformer input transient primary side current waveform, a harmonic component is obtained through screening, and a distortion coefficient of the harmonic component is calculated; substituting the distortion degree coefficient and the initial residual magnetism quantity of the iron core into the established hysteresis loop model to obtain a working point track of the transformer iron core at the moment of input; and based on the dynamic change characteristic of the working point track, the working point track is corrected by combining the micro magnetic conductivity parameter of the iron core material, and an evaluation index of the magnetizing inrush current suppression capability of the transformer is obtained. According to the method, the dynamic characteristics and the nonlinear loss characteristics of the inrush current harmonic waves are quantified, the inrush current risk when the transformer is put into operation is effectively reduced, and the safety and the stability of power system operation are enhanced.

Provided is a magnetic recording medium that is capable of increasing the reproduction output.A magnetic recording medium is a tape-shaped magnetic recording medium and includes a recording layer. A nucleation magnetic field Hn of the magnetic recording medium satisfies a relationship of Hn≥0 [Oe], and the magnetic recording medium satisfies a relationship of the following formula (1).(Mrt)0.5×f⁡(Hs)≥0.7(1)(wherein, in the formula (1), Mrt represents a product of a residual magnetization amount Mr of the magnetic recording medium and a thickness t of the recording layer. Hs represents a saturation magnetic field of the magnetic recording medium. In a case where Hs≤8500 [Oe], f(Hs)=1.00, and in a case where Hs>8500 [Oe], f(Hs)=1 / (1+(Hs−8500) / 8500).).

The present invention discloses a system and method for measuring the remanent magnetism of ferromagnetic materials, belonging to the field of electromagnetic parameter measurement technology. The system includes a fluxgate sensor array, a data integrator, and a host computer; the fluxgate sensor is used to measure the magnetic induction intensity and transmit it to the host computer; the host computer is used to obtain the residual magnetization intensity matrix and the magnetic induction intensity matrix, thereby calculating the conversion matrix, and combining the uniqueness of the conversion matrix to verify the uniqueness of the remanent magnetization intensity of the desired ferromagnetic material; under the premise that the geomagnetic field can be ignored, according to the constitutive relationship B=μ0(H+M), the magnitude and direction of the remanent magnetization component of the material can be obtained and displayed in real time from the remanent magnetization intensity. The measurement system and measurement method proposed in the present invention measure the remanent magnetism of ferromagnetic materials by combining a magnetic field sensor with a COMSOL Multiphysics model, and have the advantages of simple operation, real-time display, reliable results, applicability to measuring the remanent magnetism of ferromagnetic materials with irregular shapes or uneven remanent magnetism distribution, and clear and novel principles.

The application discloses a device and a method for rapidly measuring residual magnetism of a tooth surface, and belongs to the technical field of residual magnetism measurement. The device comprises a probe gear module and a signal processing module. The probe gear module comprises a probe gear for driving a meshing rotation of a detected gear, and a Hall sensor array uniformly arranged on each tooth surface of the probe gear. The Hall sensor array is uniformly arranged on each tooth surface of the probe gear. The probe gear is meshed with the detected gear and drives the detected gear to synchronously rotate. During the rotation, each tooth surface of the probe gear is sequentially meshed with a tooth surface of the detected gear. Meanwhile, three-axis Hall sensor array elements located at the meshing point position collect residual magnetism signals of corresponding positions of the detected tooth surface of the detected gear. Point-by-point collection and measurement of residual magnetism of all tooth surfaces of the detected gear are realized. The application does not need a complex scanning mechanism, and can complete rapid measurement of multiple tooth surfaces and multiple points through gear meshing rotation. The application has the advantages of high measurement efficiency, full direction information, easy industrial integration and the like.

This sintered magnet comprises a first phase having a main phase of Sm-Fe-N-based crystal grains with a Th2Zn17-type structure and a second phase consisting of an alloy containing at least one or more elements selected from Group 2 elements and rare earth elements, the alloy having a temperature range of 180-620°C, wherein a residual magnetization is 10.0 kG or more.

The application discloses a kind of self-adapting gyro wheel probe based on magnetic hysteresis phase change, boiler detection system and method, probe includes flexible wheel shell, granular filling cavity in wheel shell, hard magnetic granular material filled in cavity, excitation coil assembly fixed in gyro wheel axis of rotation and control circuit.Control circuit applies positive pulse current in detection position, so that hard magnetic granular material is magnetized and forms chain-shaped obstruction structure, and gyro wheel is switched from flexible state to rigid state;After positive pulse stops, particle relies on self remanence and intergranular mechanical friction force to keep obstruction state, and applies reverse pulse current to remove obstruction after detection is completed.The application utilizes the remanence effect of hard magnetic particles to realize rigid self-retention after power failure, shortens the coil energization time to the order of pulse width, reduces the heat output, and can work stably in a 300-450℃ boiler environment without active cooling, while avoiding the interference of continuous electromagnetic field on detection signal.

To suppress temperature variations on the substrate while improving adhesion between the substrate and the metal mask. [Solution] The substrate holder comprises a main body having residual magnetization and generating a temperature gradient when current is supplied, and a main surface provided on one side of the temperature gradient in the main body, which attracts the metal mask on the substrate with the magnetic force of the residual magnetization.

The present invention relates to the field of filter element detection technology, and in particular to a silver-based composite filter element detection method and system. The present invention draws a magnetization curve according to an initial magnetic induction intensity value, a plurality of first magnetic induction intensity values, and a second magnetic induction intensity value. By analyzing the magnetization curve, the magnetic response data of the silver-based fiber under different external magnetic field intensities can be quickly obtained. The external magnetic permeability of the silver-based fiber is calculated according to the plurality of second magnetic induction intensity values ​​and the first magnetic induction intensity value. Compared with traditional chemical analysis methods such as atomic absorption spectroscopy, the calculation of the external magnetic permeability can usually be completed more quickly, making the evaluation of the silver content of the silver-based fiber more accurate. The magnetic susceptibility of the silver-based fiber is obtained according to the magnetization curve. The relative amount of the silver content can be indirectly inferred by calculating the magnetic susceptibility. The silver content is calculated according to the magnetic susceptibility, the external magnetic permeability, the residual magnetization intensity, and the plurality of saturation magnetization intensities, so that the silver content can be calculated in more detail and accurately.

The application provides a method for simultaneously improving the remanence and coercivity of a micrometer-scale NdFeB-based permanent thick film. The method is to introduce a combined layer during the growth of the NdFeB-based thick film, and the combined layer is arranged between hard magnetic layers, and the arrangement structure of the combined layer is: isolation layer / soft magnetic layer / isolation layer. The non-magnetic layer in the combined layer acts as an isolation layer to increase the coercivity to a certain extent, and the soft magnetic layer improves the remanence through long-range interaction between the hard magnetic layer and the thick film. The isolation layer is preferably Ta, and the soft magnetic layer is preferably Fe. When the combined layer is inserted into 7 layers, and the thickness of the soft magnetic layer is 80 nm, the remanence of the permanent thick film reaches 1.2 T, and the coercivity is maintained at above 1.5 T. The method provides performance guarantee for the use of the NdFeB-based permanent thick film in MEMS and micro permanent magnet motors.

Provided is a rare earth magnet capable of improving both residual magnetization and coercive force. The rare earth magnet of the present disclosure includes: a main phase; and a grain boundary phase present around the main phase. A total composition in atomic ratio is represented by the formula R1xT(100−x−y−z)(B(1−s)Cs)yMz, R1 is one or more elements selected from the group consisting of Nd, Ce, La, Pr, Gd, Tb, Dy, and Ho, T is one or more elements selected from the group consisting of Fe, Co, and Ni, M is one or more elements selected from the group consisting of Ga, Al, Cu, Au, Ag, Zn, In, and Mn and unavoidable impurity elements, and 12.0≤x≤20.0, 5.00≤y≤20.0, 0≤z≤2.0, and 0.07≤s≤0.17 are satisfied. The main phase has a crystal structure of R2Fe14B type, and R is a rare earth element.

The present application provides a film that can achieve a coercive force Hc of 2.00 kOe or more and a residual magnetization Mrt per unit area of 2.00 memu / cm 2 The in-plane magnetization film has a thickness of 20 nm or more and 80 nm or less, contains 45 at% or more and 80 at% or less of the metal Co, contains 20 at% or more and 55 at% or less of the metal Pt, contains 3 vol% or more and 25 vol% or less of the oxide with respect to the entirety of the in-plane magnetization film, and has an average particle diameter in the in-plane direction of the magnetic crystal grains of 15 nm or more and 30 nm or less.

Provided is a rare earth magnet obtained by subjecting an R—Fe—B-based alloy containing R, wherein R represents a rare earth element containing Nd, Fe, and B to hot plastic processing. The rare earth magnet has a structure of a main phase containing an R2Fe14B compound, an axis of easy magnetization is oriented in a minor axis direction of a crystal grain of the main phase, a thickness dimension in a direction of the axis of easy magnetization is from 0.07 mm to 0.2 mm, and a decrease rate of residual magnetization is 5% or less, wherein the decrease rate (%) of residual magnetization is a rate of decrease in residual magnetization with respect to when residual magnetization of the rare earth magnet having the thickness dimension of 0.5 mm is defined as 100%.

A method for preparing high magnetic performance (Sm x Y 1‑x )Co5 rare earth magnetic particles by chemical method belongs to the field of rare earth magnetic materials. Specifically relates to a kind of new technology using chemical liquid phase synthesis combined with calcium reduction reaction, preparation of high magnetic performance (Sm x Y 1‑x )Co5 ternary alloy magnetic powder. Through chemical coprecipitation combined with hydrothermal reaction, Sm(OH)3 / Y(OH)3 / Co(OH)2@Ca(OH)2 crystalline state mixed precursor is prepared, and a certain amount of metal calcium particles, KCl and CaCl2 diffusion medium are uniformly mixed in argon atmosphere to occur complete calcium reduction reaction, and the magnetic powder is prepared. The incorporation of yttrium element improves the saturation magnetization and remanence of the magnetic powder, but the coercivity of the magnetic powder is slightly reduced. This method provides a new idea for preparing high-performance rare earth magnetic particles.

The invention provides a neodymium-iron-boron material recycling process, and belongs to the field of neodymium-iron-boron waste material recycling. The preparation process comprises the following steps: preparing a mixed leaching solution; carrying out ball-milling roasting, stirring and leaching; preparing a composite extracting agent; adding a composite extraction agent for extraction and separation; and carrying out heating reaction with metal calcium and regenerating the neodymium-iron-boron magnet. Metal elements in the neodymium iron boron material are leached out through the mixed leaching solution, then rare earth ions are extracted out through the composite extraction agent, rare earth elements are separated from non-rare earth elements, all the metal elements are recycled in a precipitation mode, and the recovery rate of the neodymium iron boron material is increased. The neodymium-iron-boron magnet is obtained through regeneration such as calcination, mixing and heating reaction with metal calcium particles, mixing and smelting with ferroboron, crushing and grinding, compression molding and vacuum sintering, the oxygen content is extremely low, and non-ferromagnetic rare earth metal or alloy is not added, so that the residual magnetization intensity and the saturation magnetization intensity of the regenerated neodymium-iron-boron magnet can be effectively improved; and the effect of improving the practicability of the regenerated neodymium-iron-boron magnet is achieved.

The invention discloses a zinc-doped manganese cobaltate-based magnetic refrigeration material and a preparation method and an isothermal residual magnetization measurement method thereof, the chemical general formula of the magnetic refrigeration material is as follows: x is more than or equal to 0.1 and less than or equal to 0.4, and when the magnetic field is 5T, the RCP value of the material is up to 82.13 J / kg. The preparation method comprises the following steps: oscillating, ball-milling, drying and grinding the raw materials prepared according to the stoichiometric ratio; pre-sintering the product twice, naturally cooling and grinding; mixing and grinding polyvinyl alcohol and the pre-sintered product, and tabletting and molding; calcining to remove polyvinyl alcohol; and sintering for 10-30 hours at the temperature of 980-1150 DEG C to obtain the zinc-doped manganese cobaltate-based magnetic refrigeration material.

The invention discloses a motor, a compressor and refrigeration equipment. The motor comprises a stator assembly and a rotor assembly. The stator assembly comprises a stator iron core; the rotor assembly is rotatably arranged in the stator assembly, the rotor assembly comprises a rotor iron core and a rotor magnet, the rotor iron core is provided with a plurality of magnet grooves, the plurality of magnet grooves are arranged at intervals along the circumferential direction of the rotor iron core, each magnet groove extends in the axial direction of the rotor iron core, the outer diameter of the stator iron core is D1, the number of pole pairs of the rotor assembly is P, the number of the rotor magnets under each pole is a, the total width of the rotor magnets is L1, the length of the rotor magnets in the axial direction of the rotor iron core is h, and the residual magnetization intensity of the rotor magnets is br, and the motor is small in size and large in output torque, and meanwhile, the efficiency and the power density of the motor can be improved.

Provided are a magnetic recording medium including a non-magnetic support and a magnetic layer containing a ferromagnetic powder, a magnetic tape cartridge including the magnetic recording medium, and a magnetic recording reproduction device. The magnetic field 0.3 of the magnetic recording medium is between 4.0 kOe and 8.0 kOe (both inclusive). The magnetic recording medium is a magnetic tape or a magnetic disk. The magnetic field 0.3 is a value on the high magnetic field side of the two values on the horizontal axis at which the value on the vertical axis is 0.3, in a graph in which the residual magnetization obtained by measurement with a vibrating sample magnetometer as the vertical axis value is plotted against the value of the applied magnetic field in the longitudinal direction of the magnetic tape or in the radial direction of the magnetic disk on the horizontal axis, and the differential curve obtained by differentiating these plots is normalized to a maximum value of 1 on the vertical axis.

To provide a method for manufacturing a magnetoplumbite-type hexagonal ferrite magnetic powder capable of making a ferrite-based bond magnet exhibit excellent residual magnetization.SOLUTION: A first embodiment of the invention is a method of producing a magnetoplumbite-type hexagonal ferrite magnetic powder, including a firing step of firing a mixture containing a raw material powder and a metal chloride to obtain a fired product, and a pulverizing step of pulverizing the fired product to obtain a powder, in which a molar ratio of an amount of Cl contained in the metal chloride to an amount of Fe contained in the raw material powder is 0.002 or more and 0.020 or less.SELECTED DRAWING: None