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624 results about "Saturation (magnetic)" patented technology

Seen in some magnetic materials, saturation is the state reached when an increase in applied external magnetic field H cannot increase the magnetization of the material further, so the total magnetic flux density B more or less levels off. (It continues to increase very slowly due to the vacuum permeability.) Saturation is a characteristic of ferromagnetic and ferrimagnetic materials, such as iron, nickel, cobalt and their alloys.

Fe-Si-Nb-B-Cu-Er amorphous alloy and preparation method and application thereof

The invention relates to a Fe-Si-Nb-B-Cu-Er amorphous alloy and a preparation method and application thereof, and belongs to the technical field of metal materials. The atomic percent expression of the Fe-Si-Nb-B-Cu-Er amorphous alloy disclosed by the invention is (Fe < 83 > Si < 3 > Nb < 4 > B < 9 > Cu < 1 >) < 100-x > Er < x >, wherein x is equal to 3.5 to 4.5. The rare earth element Er is added to optimize the soft magnetic performance of a Fe-Si-Nb-B-Cu amorphous alloy system, the coercive force of the Fe-Si-Nb-B-Cu amorphous alloy system is reduced, the preparation method is simple and easy to implement, and the Fe-based amorphous alloy with the excellent soft magnetization performance is obtained. The magnetization intensity of the amorphous alloy is sharply increased along with increase of a magnetic field under a low magnetic field and then gradually reaches saturation, typical soft magnetic performance is presented, and the amorphous alloy has wide application space in the field of magnetic materials.
Owner:ELECTRIC POWER RES INST OF GUANGDONG POWER GRID CO LTD

Stator assembly, compressor and refrigeration equipment

The invention discloses a stator assembly, a compressor and refrigeration equipment, and relates to the technical field of motors. The stator assembly comprises a stator core formed by stacking a plurality of amorphous alloy sheets, the stator core comprises a yoke part, a tooth part and a shoe part, and the stator core is formed by stacking a plurality of amorphous alloy sheets, so that the iron loss of the stator assembly can be reduced. For a motor, the area of a stator slot is expected to be as large as possible to increase the winding wire diameter so as to reduce copper loss, and the smaller the minimum width of a tooth part is, the better is, but the smaller the width of the tooth part is, the more likely to cause magnetic field saturation. In order to reasonably design the minimum tooth width of the tooth part so as to reduce the problem of magnetic voltage drop increase caused by magnetic field saturation, the minimum tooth width Wt of the tooth part is set in a range of 2piD / 9Q to 2piD / 3Q, so that the area of the stator slot can be effectively increased, the problem of magnetic voltage drop increase caused by magnetic field saturation can be improved, the magnitude of current can be reduced, and the service life of the stator slot can be prolonged. The working efficiency of the motor is improved.
Owner:ANHUI MEIZHI COMPRESSOR CO LTD

Magnetic saturation evaluation method and magnetic saturation evaluation system for magnetic component in strong magnetic field environment

The invention relates to a magnetic saturation evaluation method and system for a magnetic component in a strong magnetic field environment, and the method comprises the steps: constructing a target component model of a to-be-tested magnetic component according to a target geometric parameter and a target material parameter, and respectively setting excitation and boundary conditions of the target component model according to the target working current parameter and the target working environment magnetic field parameter, and performing simulation. The method comprises the following steps: acquiring simulated BH data of a target position in a target component model and corresponding simulated working environment magnetic induction intensity, and determining that the target component model reaches a magnetic saturation state according to the simulated BH data of the target position; and taking the corresponding simulated working environment magnetic induction intensity as a simulated saturated external magnetic field threshold value of the to-be-tested magnetic component. According to the embodiment of the invention, analog simulation of the saturation external magnetic field threshold of the to-be-tested magnetic component in the magnetic field environment is realized, and important support can be provided for model selection application and design optimization of the magnetic component in the high-intensity magnetic field environment.
Owner:CHINA ELECTRONICS RELIABILITY AND ENVIRONMENTAL TESTING INSTITUTE ((THE FIFTH INSTITUTE OF ELECTRONICS MINISTRY OF INDUSTRY AND INFORMATION TECHNOLOGY) (CHINA SAIBAO LABORATORY) +1

Magnetic saturation detector with single and multiple transverse windings

Magnetic saturation detectors for power converters are presented herein. An energy transfer element has an input power winding wrapped around a center post. Single or multiple transverse windings are positioned perpendicular to the input power winding and coupled to receive a transverse current that provides a transverse magnetic flux density within the energy transfer element. The transverse magnetic flux density produces a transverse voltage waveform. A voltage detection circuit is configured to receive the transverse voltage waveform and detect a change in the sign of the slope of the transverse voltage waveform. The change in the sign of the slope indicates magnetic saturation. The voltage detection circuit is configured to detect an occurrence of an extremum in the transverse voltage waveform. The extremum indicates the change in the sign of the slope.
Owner:POWER INTEGRATIONS INC

Defect detection system based on bias alternating current magnetization modulation TMR sensor

The invention discloses a defect detection system based on a bias alternating current magnetization modulation TMR sensor, and the system is characterized in that through the cooperation of an alternating current and direct current magnetization module, a TMR sensor and a defect prediction module, the alternating current and direct current magnetization module is used for simulating an alternating current and direct current superimposed magnetic field test environment, and a reverse alternating current and direct current magnetic saturation magnetic field is formed; the TMR sensor obtains defect signal characteristics of a to-be-detected workpiece and sends the obtained defect signal characteristics of the to-be-detected workpiece to the defect prediction module, and the defect prediction module achieves full-scale detection of defects from 20 micrometers to millimeter by analyzing peak values (micron-scale narrow defects) and waveform widths (millimeter-scale defects) of alternating-current waveforms. The balance of high sensitivity and wide range of the same sensor is realized, and meanwhile, the dual requirements on precision and efficiency in actual detection are met. Meanwhile, through alternating current and direct current magnetic field cooperative modulation, the measuring range TMR sensor is expanded to 300 Gs, and the full range from weak magnetic leakage to strong magnetic leakage is covered.
Owner:NANCHANG HANGKONG UNIVERSITY

Modified high-performance non-magnetic hard alloy and preparation process thereof

The invention belongs to the field of hard alloy materials, and provides a modified high-performance non-magnetic hard alloy and a preparation process thereof. The surface of a WC particle is chemically plated with a Ni-P-B-Cr-Cu amorphous shell layer, and a binding phase is converted into Ni3P and Ni3B nanophase through two-stage sintering. The WC alloy comprises the following components in parts by weight: 85-95 parts of WC, 12-25 parts of a binding phase and 0.5-1.4 parts of a grain growth inhibitor, the nanophase accounts for 35-50% of the volume of the binding phase and 35-50% of the total volume of the binding phase, and the grain size is 80-125 nm; the average grain size of WC is 0.6-1.0 [mu] m; and the thickness of an interface P enrichment layer is 8-15 nm (the coverage rate is 85-95%). Through interface engineering and controlled crystallization from amorphous to nanocrystalline, the relative magnetic conductivity is 1.001-1.015, the hardness HRA is 90.5-93.0, the strength TRS is 2.2-3.0 GPa, the toughness KWP is 300-450 N / mm, and the magnetic saturation strength is 0.02-0.15 T. The problem of decoupling of the magnetic property and the mechanical property of a traditional non-magnetic hard alloy is solved, and the non-magnetic hard alloy is suitable for magnetic sensitive environments such as semiconductor equipment, precise measurement, MRI tools and oil service logging.
Owner:CHENGDU GOLDEN WOLFRAN CARBIDE CO LTD

Method and system for controlling low inductive reactance and low transient impulse voltage

The invention belongs to the technical field of low-voltage power distribution, and particularly relates to a control method and system for low inductive reactance and low transient impulse voltage, the magnetic flux density and the change rate of a magnetic core are collected in real time through a sensor, a dynamic threshold value is calculated based on the magnetic flux density, and the critical point of the magnetic core entering a nonlinear magnetization area is accurately identified. And comparing the magnetic flux density monitored in real time with a dynamic threshold value, generating a deviation signal and judging the state of the magnetic core. Once it is confirmed that the magnetic core is in a non-linear magnetization state, an adjustment mechanism is triggered immediately, winding current distribution is adjusted to change the magnetic flux path length of the magnetic core, and periodic pulse signals are applied to prevent depth saturation of the magnetic core. In addition, by monitoring the adjusted magnetic core magnetic flux density recovery rate, demagnetization processing parameters and pulse signal strategies are optimized, and continuous and efficient operation of the system is ensured. According to the method, the transient voltage suppression capability and stability of the system are remarkably improved, and the overall performance and reliability are enhanced.
Owner:HUANGBANG CHUANGKE (HUIZHOU) INTELLIGENT TECH CO LTD

A nanocrystalline current transformer with DC component resistance and its use method

The present invention discloses a nanocrystalline current transformer with DC component resistance and a method for using the same, comprising: a current transformer having a magnetic core hole extending from front to back in the middle of the front side of the current transformer. The device is provided with a secondary-side disconnection detection and protection mechanism, which effectively prevents the internal magnetic field imbalance of the transformer caused by the disconnection of the secondary circuit, avoids the core magnetic flux saturation and the generation of potential high electromotive force, thereby protecting the transformer itself and peripheral equipment, and reducing the risk of power system failures such as fire or short circuit. At the same time, a live conductor centering fixing mechanism is provided to ensure the stable centering position of the conductor in the transformer core hole, optimize the magnetic field distribution, reduce magnetic leakage, significantly improve the accuracy and stability of current measurement, and reduce measurement fluctuations introduced by conductor shaking, providing more accurate data support for harmonic analysis, fault detection, and power quality monitoring of the power system.
Owner:SHANDONG HUANBANG ELECTRONIC TECH CO LTD

Method for low-temperature one-step synthesis of strong magnetic hydrophobic fe3o4 nanoparticles, fe3o4 nanoparticles and application

The application relates to a method for one-step synthesis of strong magnetic hydrophobic Fe3O4 nanoparticles at low temperature and the Fe3O4 nanoparticles and application, and belongs to the technical field of nano material preparation. The method comprises the following steps: adding a ferrous sulfate solution into a mixed solution of sodium hydroxide and sodium nitrate, heating and stirring to react, adding oleic acid in the reaction process, and obtaining black Fe3O4 crystals after the reaction is completed. The saturation magnetization of the obtained strong magnetic hydrophobic Fe3O4 nanoparticles can reach 85.69 emu / g at most, and the water contact angle can reach 148.95 DEG. The one-step synthesis reaction only needs to use oleic acid as a regulator, avoids an extreme high-temperature and high-pressure environment, does not need to use a toxic chemical solvent, the condition is mild, the process is simple, the operation condition is easy to control, and the method has a wide application prospect.
Owner:CENT SOUTH UNIV

Ferromagnetic material internal defect leakage magnetic field increasing method based on alternating current and direct current composite magnetization

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.
Owner:NANCHANG HANGKONG UNIVERSITY

Marine deepwater weakly cemented sandstone saturated water nuclear magnetic T2 spectrum correction method

The invention discloses an ocean deepwater weakly cemented sandstone saturated water nuclear magnetic T2 spectrum correction method, which comprises the following steps: 1, making a standard rock sample, and drying the rock sample until the quality is kept stable; 2, saturating the dried rock sample to a completely saturated state by using a turbid liquid, and carrying out nuclear magnetic T2 spectrum measurement to obtain a nuclear magnetic T2 spectrum of the weakly cemented rock sample under the condition that pores contain tiny solid impurities; 3, after displacing and drying the rock sample in the previous step, carrying out saturated water treatment by utilizing pure water, and then carrying out nuclear magnetic T2 spectrum measurement to obtain a nuclear magnetic T2 spectrum of the rock sample in a state that the pores contain the pure water; 4, constructing the nuclear magnetic T2 spectrums in the two states into a data set, and inputting the data set into a deep neural network model for training; and 5, correcting the nuclear magnetic T2 spectrum under the condition that the pores contain the tiny solid impurities by using the trained deep neural network model. According to the method, the nuclear magnetic T2 spectrum is corrected by using the deep neural network model, and the problem of signal attenuation distortion caused by impurity interference is effectively solved.
Owner:CHENGDU UNIVERSITY OF TECHNOLOGY

Oil saturation delimiting method with jointly processing of nuclear magnetic resonant response (NMR) data of oil and rock samples in in natura condition

The present invention comprises a method for jointly processing data from the nuclear magnetic resonant (NMR) response of oil and rock samples in in natura condition, and its main product is the delimitation of the oil saturation (So) present in the rock samples, i.e., the determination of the range of admissible values of the volumetric fraction of the porous volume of the rock occupied by such fluid. The method requires a small volume of oil, originating from or of a composition similar to the oil present in the rock being tested, since it is based on both the measurement of the NMR response of the rock sample and the response of the fluid sample. These two sets of data feed a statistical inference scheme that (1) determines a range of admissible values for the So of the sample, delimited by the minimum and maximum oil saturation values compatible with the two sets of data presented; (2) produces, for each of these extreme values of admissible So, a decomposition of the rock relaxation time spectrum into two complementary spectra, the first highlighting the signatures relating to oil and the second comprising the distribution of the rock relaxometric signatures that cannot correspond to such fluid under the prescribed saturation condition.
Owner:PETROLEO BRASILEIRO SA PETROBRAS

Plastic package magnetic material for chip inductor, preparation method of plastic package magnetic material and inductor

The invention discloses a plastic package magnetic material for a chip inductor, a preparation method of the plastic package magnetic material and the inductor. The plastic package magnetic material comprises 96wt%-99wt% of alloy powder, 1wt%-4wt% of a resin layer and at least two atomic layer deposition layers, the two adjacent layers in the at least two atomic layer deposition layers are made of different materials; the at least two atomic layer deposition layers are coated on the outer surface of the alloy powder, and the resin layer is coated on the outer surfaces of the at least two atomic layer deposition layers. The plastic package magnetic material provided by the invention has relatively high magnetic conductivity, high saturation and low loss in a low-frequency band while having good fluidity, insulation and voltage resistance, so that miniaturization, lightness, thinness and high performance of an inductor are realized.
Owner:SHENZHEN SUNLORD ELECTRONICS

Composite groove type stator punching sheet and motor formed by same

The invention provides a composite groove type stator punching sheet and a motor formed thereof.The stator punching sheet comprises M composite grooves distributed in the circumferential direction of the stator punching sheet, each composite groove comprises a first winding groove and a second winding groove which are distributed along the two sides of the center line of the groove, and the first winding grooves and the second winding grooves are different in structure; the inner side wall of the first winding groove comprises at least one section of arc, and the inner side wall of the second winding groove does not comprise an arc and is only enclosed by straight lines; m is an integer greater than or equal to 3. The first winding slots effectively modulate an air-gap magnetic field by utilizing smooth arc-shaped contours of the first winding slots, so that cogging torque and torque pulsation caused by magnetic conductance change are greatly reduced; the second winding groove is used for enhancing the magnetic circuit capacity and ensuring that the main magnetic flux can pass through efficiently without saturation, so that the harmonic content and the stator iron loss are greatly reduced; the first winding groove and the second winding groove complement each other in the aspects of electromagnetic performance and process advantages and are synergistically enhanced, so that a high-performance and low-cost synergistic effect is realized.
Owner:ZHUHAI LANDA COMPRESSOR

High-power inverter and control method thereof

The invention discloses a high-power inverter and a control method thereof, and belongs to the technical field of power electronics, the high-power inverter comprises a sensing enhanced magnetic assembly, the sensing enhanced magnetic assembly comprises a high-thermal-conductivity metal shell, a magnetic core arranged in the high-thermal-conductivity metal shell, a main power coil, a high-precision sensing coil and an integrated thermal probe; wherein the high-precision sensing coil is wound by clinging to a central column of the magnetic core, the main power coil is coaxially wound on the outer side of the high-precision sensing coil, and the magnetic core, the main power coil and the high-precision sensing coil jointly form an inductor core body. According to the invention, the controller can monitor the working point of the magnetic core on the magnetization curve in real time, so that the margin of the magnetic core away from the magnetic saturation state is directly judged.
Owner:XIAMEN YIKE ELECTRONICS

Transformer direct current magnetic bias temperature rise calculation method, system, medium and equipment

The invention discloses a transformer direct current magnetic bias temperature rise calculation method, system, medium and equipment, and the method comprises the steps: carrying out the classification estimation of the non-linear magnetic resistance value of each part of an iron core structure based on the magnetization characteristic of an iron core material, and obtaining the magnetic resistance estimation value of each part; building a transformer iron core magnetic circuit simulation model according to the magnetic resistance estimated value of each part to obtain a saturation magnetization characteristic phi-i curve of the transformer; a transformer circuit-magnetic circuit model is built, and winding current and iron core magnetic flux are obtained through circuit and magnetic circuit coupling calculation; establishing a transformer thermal circuit lumped parameter model under the direct current magnetic bias condition based on a thermoelectric analogy method, and fitting thermal capacity and thermal resistance parameters in the transformer thermal circuit lumped parameter model according to data of a transformer temperature rise experiment; in combination with short-circuit test data of the transformer, calculating winding loss of the transformer under direct-current magnetic bias; based on the BP loss characteristic of the iron core material, calculating the iron core loss of the transformer under the direct current magnetic bias; and temperature rise is calculated based on the transformer thermal circuit lumped parameter model.
Owner:XI AN JIAOTONG UNIV

Millisecond-level cooperative inhibition method for flexible load of harbor district based on magnetic flux jump prediction

The invention discloses a port area flexible load millisecond-level cooperative suppression method based on magnetic flux jump prediction, and the method comprises the steps: obtaining the external vibration and electrical data of a transformer, combining the Bayesian inversion of physical constraint, and reconstructing an internal three-dimensional magnetic flux field; based on time sequence evolution of the magnetic flux field, a dual-mode self-adaptive prediction algorithm is adopted, and a magnetic flux jump early warning vector containing jump time, amplitude and position is generated; and according to the early warning vector, through a multi-layer cooperative control strategy of time sequence decoupling, a control instruction for the flexible load of the harbor district is generated and executed. Advanced early warning and millisecond-level active suppression of the potential magnetic saturation risk are realized, and the operation reliability and equipment safety of a harbor district power distribution system are improved.
Owner:YANCHENG POWER SUPPLY CO STATE GRID JIANGSU ELECTRIC POWER CO

Electromagnetic radiation suppression method for flywheel energy storage system of data center

The invention relates to the technical field of flywheel energy storage electromagnetic suppression, in particular to an electromagnetic radiation suppression method for a data center flywheel energy storage system, which comprises the following steps: acquiring grounding potential data to generate a response node set, comparing a rotating speed with a power event to construct a synchronous topology, identifying a coupling path to generate a path map, and adjusting a magnetic shielding assembly. And monitoring magnetic flux change to generate an electromagnetic compatibility state report. According to the method, the sudden change potential and the recovery rate of a grounding node are analyzed, response nodes with disturbance characteristics are screened, rotating speed and load power events are fused, multi-source data response mapping in a time domain is constructed, a coupling path is recognized based on a node physical connection relation, and the magnetic saturation trend is recognized by collecting magnetic flux density and hysteresis characteristics. The excitation phase is matched to implement dynamic adjustment, the response adaptability of the shielding assembly is improved, the stability is judged according to the magnetic flux density change rate trend, the reset operation of the shielding structure is controlled, the shielding effectiveness retention is enhanced, and electromagnetic suppression in a dynamic interference scene is achieved.
Owner:SHENYANG MICRO CONTROL ACTIVE MAGNETIC LEVITATION TECH IND RES INST CO LTD

Magnetic conductance motor adopting magnetic conductance reinforcing material

The invention relates to the technical field of motors, in particular to a magnetic conductance motor adopting a magnetic conductance reinforcing material, which comprises a stator assembly and a rotor assembly which are concentrically arranged, and the rotor assembly is arranged in the stator assembly. The stator assembly is formed by radially positioning and splicing 12-24 silicon steel sheet inserts through a dovetail joint structure, traditional lamination gap loss is eliminated, T-shaped teeth (iron-nickel-based magnetically soft alloy 1J34 / 1J36) which are deeply embedded (1 / 3-1 / 2 of the tooth height) are combined, the magnetic circuit conduction efficiency is remarkably optimized through the high magnetic conductivity (larger than or equal to 60,000 H / m) and the saturation flux density (larger than or equal to 1.5 T), and the magnetic saturation risk is avoided; a non-magnetic stainless steel base body (304 / 316) is adopted on the rotor side to block a stray magnetic circuit, and a low-loss magnetic field closed loop is formed by matching the magnetism gathering design of a V-shaped neodymium iron boron insert (Br is larger than or equal to 1.2 T, Hc is larger than or equal to 900 kA / m, and the included angle is 60-90 degrees) and directional magnetism conduction of a 20-30-degree fan-shaped angle magnetic barrier insert, so that the purposes of high efficiency, low consumption, high reliability and low cost are achieved.
Owner:QUANZHOU ZHANZHENG MASCH CO LTD

Transformer magnetic powder core, transformer and preparation method of transformer magnetic powder core

The invention discloses a transformer magnetic powder core, a transformer and a preparation method of the transformer magnetic powder core, the transformer magnetic powder core comprises a main body formed by a coarse powder layer, a fine powder layer is formed on at least one matching surface, used for being in contact with another magnetic powder core of the transformer, of the main body, and the powder granularity of the coarse powder layer and the fine powder layer forms gradient distribution. A fine powder layer structure with the particle size smaller than that of a magnetic powder core body is arranged on the matching face of the magnetic powder core of the transformer, and the performance bottleneck caused by low saturation flux density, weak large-current direct-current bias capacity and size limitation of a traditional ferrite core is effectively solved through the coarse / fine powder layer particle size gradient distribution design. According to the design, by optimizing filling of the interface fine powder layer, the risk that powder falls off to form an air gap in the grinding and polishing machining process is remarkably reduced, the flatness of the matching face and the continuity of a magnetic circuit are improved, and therefore the inductance value is increased and the power loss is reduced on the basis that the comprehensive performance is guaranteed.
Owner:SHENZHEN SUNLORD ELECTRONICS

Miniaturized broadband microstrip circulator based on double-ferrite nested structure

The invention relates to the technical field of microwave ferrite devices, and discloses a miniaturized broadband microstrip circulator based on a double-ferrite nested structure, comprising a substrate, the upper surface of which is provided with a magnetic conductive sheet; a high dielectric ceramic is arranged on the magnetic conductive sheet, and a low magnetic saturation ferrite and a high magnetic saturation ferrite are sequentially nested in an inner cavity of the high dielectric ceramic; a circuit is arranged on the upper surface of the high-dielectric ceramic, and a ceramic piece and a permanent magnet are sequentially installed above the circuit. According to the circulator, a magnetic conductive sheet is additionally arranged, a structure with high dielectric ceramics as a core is constructed, the characteristic difference of two ferrite gyromagnetic materials with different magnetic saturation intensities is utilized, and the frequency resonance characteristic of a center junction is adjusted through nested arrangement, so that gyromagnetic effects under different frequencies are complementary to expand the working frequency band. Meanwhile, the high-dielectric ceramic optimizes port impedance matching and reduces electromagnetic wave reflection by virtue of a high dielectric constant, and cooperates with an internal ferrite nested structure, so that the frequency bandwidth is widened through a composite material mode, and miniaturization and broadband effects are achieved.
Owner:SHENZHEN NUOXINBO COMM CO LTD

Shale reservoir wettability dynamic determination method and system

The invention relates to the technical field of shale exploitation, and discloses a shale reservoir wettability dynamic determination method, which comprises: S1, selecting a shale plunger core, carrying out supercritical CO2 cleaning and vacuum drying, and carrying out high pressure saturation by using simulated crude oil to obtain an initial oil saturation; and S2, the saturated rock core is loaded into a high-temperature and high-pressure rock core holder, and under the simulated formation temperature and pressure condition, simulated formation water containing the paramagnetic contrast agent is injected at the constant flow speed for displacement till the water content of the outlet end reaches 98%. According to the invention, dynamic and three-dimensional space representation of wettability is realized: three modal data of nuclear magnetic resonance, resistivity and sound wave are synchronously acquired in the displacement process, so that the limitation of a traditional static method is overcome, and the dynamic process of the wettability changing along with the fluid saturation state can be captured in real time; and finally, a high-resolution three-dimensional wettability distribution map is generated, and non-uniform distribution of wettability in the core is visually revealed.
Owner:XI'AN PETROLEUM UNIVERSITY

Composite magnetic sheet filled with nanocrystalline slotted soft magnetic alloy powder and preparation method of composite magnetic sheet

The invention belongs to the technical field of magnetic shielding materials, and particularly relates to a nanocrystalline slotting and soft magnetic alloy powder filling composite magnetic sheet and a preparation method thereof. The composite magnetic sheet comprises a magnetic material layer formed by alternately compounding a nanocrystalline material layer and a double-faced adhesive tape, the magnetic material layer is provided with regularly distributed slotting structures, and the slotting structures are filled with soft magnetic alloy powder. The preparation method comprises the following steps: alternately compounding a nanocrystalline material layer and a double-faced adhesive tape to form a magnetic material layer, and performing die cutting to form a regularly distributed slotting structure; or the nanocrystalline material composite layer is subjected to die cutting to form a regularly-distributed through slotting structure, and then the structure is compounded with the composite layer which is not slotted to obtain the magnetic material layer; and then filling and fixing the slotting structure by adopting soft magnetic alloy powder to obtain the composite magnetic sheet. According to the invention, the defect of easy magnetic saturation due to local lack of magnetic materials after slotting can be avoided, and the obtained composite magnetic sheet has low loss and high saturation current at the same time.
Owner:SHENZHEN YN TECH CO LTD

Fluxgate zero flux abnormal state detection and recovery circuit and method

The invention relates to a fluxgate zero flux abnormal state detection and recovery circuit and method. The fluxgate zero flux abnormal state detection and recovery circuit comprises a fluxgate probe, a feedback control circuit, a signal sampling and processing circuit, a selection circuit, a scanning circuit or a digital control and processing module. The scanning circuit and the digital control and processing module can periodically scan a compensation current amplitude from small to large, generate a periodic compensation current waveform, forcibly excite a magnetic core to exit a magnetic saturation region so as to recover a zero magnetic flux state, capture a signal of the compensation current in time, and keep normal work when the current suddenly changes or is saturated and does not work. Switching the compensation current control right of the feedback winding from a feedback signal of a feedback control circuit to a scanning signal when it is judged that the feedback winding is in the zero magnetic flux abnormal state; and when it is detected that the excitation magnetic core recovers to the zero magnetic flux state, the compensation current control right is switched from the scanning signal to the feedback signal. The reliability of the fluxgate sensor can be improved.
Owner:HEBEI UNIV OF TECH

High-stability magnetic liquid and preparation method thereof

The invention discloses a high-stability magnetic liquid and a preparation method thereof, and belongs to the field of magnetic fluid nano functional materials related to ships. The magnetic liquid comprises a metal-doped iron oxide nano-particle core, a double-layer surface modification layer composed of oleic acid and a silane coupling agent, and a composite carrier liquid formed by compounding poly-alpha olefin synthetic oil and perfluoropolyether and adding nano-diamond. The preparation method comprises the following steps: firstly, coprecipitating and calcining to obtain metal-doped iron oxide nanoparticles, then carrying out double-layer coating modification, and finally carrying out mixed ball milling, ultrasonic treatment and magnetic separation purification on the metal-doped iron oxide nanoparticles and the composite carrier liquid. The saturation magnetization intensity of the magnetic liquid reaches 92-95 emu / g, the magnetic liquid can work for a long time under the high-temperature working condition, the heat conductivity coefficient is increased by 2-3 times, and the redispersibility is excellent. The problems that a traditional magnetic fluid is low in magnetic performance, prone to failure at high temperature, poor in dispersion stability and the like are solved, and the magnetic fluid is suitable for aerospace, high-end manufacturing, ship propulsion and other extreme scenes.
Owner:CHANGCHUN NORMAL UNIV

Method and device for optimizing uniformity of central magnetic field of annular segmented iron yoke

The invention provides an annular segmented iron yoke center magnetic field uniformity optimization method and device, relates to the technical field of superconducting electrical iron yokes, and solves the technical problem that the uniformity of a superconducting magnet center magnetic field is difficult to improve in the prior art. The method specifically comprises the following steps: acquiring physical basic parameters of the superconducting magnet; establishing a two-dimensional axisymmetric calculation model, determining radial and axial calculation ranges, and generating a two-dimensional grid coordinate matrix; calculating an initial static magnetic field by using the two-dimensional grid coordinate matrix based on the Biot-Savart law and the axial symmetry characteristic; constructing an annular yoke multi-parameter optimization problem, and performing global parameter search by adopting a genetic algorithm to obtain yoke optimization parameters; based on the magnetic dipole theory and the saturation characteristic of the ferromagnetic material, a correction model of the yoke to the magnetic field is established by combining yoke optimization parameters, an additional magnetic field generated by the yoke is calculated, the additional magnetic field and the initial static magnetic field are superposed, and the total magnetic field intensity is obtained. The method is used for optimizing the uniformity of the iron yoke center magnetic field.
Owner:HEFEI XIHE SUPERCONDUCTING TECH CO LTD

Amorphous nanocrystalline magnetic material and preparation process thereof

The invention discloses an amorphous nanocrystalline magnetic material and a preparation process thereof, and relates to the technical field of magnetic materials, the amorphous nanocrystalline magnetic material comprises the following components by weight: 70-85 parts of raw material iron, 5-10 parts of raw material silicon, 5-12 parts of raw material boron, 0.5-3 parts of raw material niobium, 0.1-2 parts of raw material molybdenum, 0.1-1 part of raw material copper, and the balance trace elements. According to the amorphous nanocrystalline magnetic material and the preparation process thereof, the material simultaneously meets high saturation flux density, low loss and excellent thermal stability, in addition, a double-roller quenching method and a rapid solidification and low-temperature annealing process are combined, overgrowth of crystal grains is avoided, the high-frequency stability and mechanical strength of the material are ensured, the process is simple, the cost is low, and the method is suitable for industrial production. The method is suitable for industrial production.
Owner:LOUDI CITY LITONG MAGNETOELECTRICITY SCI & TECH

Analytic calculation method suitable for magnetic saturation current of high-voltage shunt reactor under resonance working condition

The invention discloses an analytical calculation method suitable for the magnetic saturation current of a high-voltage shunt reactor under a resonance working condition. The method comprises the following steps: establishing an electromagnetic coupling equivalent circuit model under the resonance working condition of the shunt reactor considering the magnetic saturation characteristic of an iron core; dividing the magnetization characteristic of the iron core into an unsaturated section and a saturated section through piecewise linearization processing of the magnetization curves, and setting the slopes of the two sections of magnetization curves and the magnetic field intensity at the knee point of a demarcation point; according to the working state of the reactor, constructing an electromagnetic coupling equation set containing a first-order conducting term coefficient in an unsaturated state, and deducing a time domain analytical expression of winding current; constructing an electromagnetic coupling equation set considering a zero-sequence coupling effect in a saturated state, simplifying resistance parameters, and then deducing a current solution expression in an equivalent inductance matrix form; the current value of the three-phase winding of the shunt reactor is monitored in real time, when the current amplitude of the winding reaches a knee point value, state switching is triggered, the final value of the previous state is used for updating the initial condition of the next state, and the current waveform is solved.
Owner:TIANJIN UNIV +2

Large-current magnetic saturation suppression method for high-temperature-resistant magneto-sensitive element

The invention discloses a high-current magnetic saturation suppression method for a high-temperature-resistant magneto-sensitive element, which belongs to the technical field of electromagnetic measurement and comprises the following steps: acquiring a working temperature parameter and a measured current parameter of the magneto-sensitive element; performing operation by using a nonlinear coupling function to obtain a magnetic circuit control instruction; based on the instruction, adjusting the gradient composite magnetic core to obtain a magnetic conductivity distribution state; when it is monitored that the temperature value of the outer layer material exceeds a temperature threshold value, the thermally-induced deformation magnetic circuit switch is driven to deform; the movable magnetic shunt piece is driven by deformation action to cut into the main magnetic circuit to form a magnetic flux shunt path; the air gap area of the magnetic flux shunting path is used for exciting an eddy magnetic field, magnetic saturation is inhibited, and a stable magnetic field signal is output. According to the invention, a multi-stage cooperative control strategy combining gradient magnetic core dynamic adjustment, thermally induced physical shunting and eddy current suppression is adopted, so that the magnetic saturation phenomenon under high temperature and large current can be effectively suppressed, measurement drift is compensated, and the working stability and precision of the magnetosensitive element are remarkably improved.
Owner:NANJING ZHONGXU ELECTRONICS SCI & TECH

Nickel-zinc copper ferrite and preparation method and application thereof

The application relates to a nickel-zinc-copper ferrite and a preparation method and application thereof, the nickel-zinc-copper ferrite comprising main components and auxiliary components; the main components comprise Fe2O3 64-66.7 mol%, NiO 9-12 mol%, ZnO 13.5-19 mol% and CuO 3-9.5 mol% with the total mole percentage being 100 mol%; the auxiliary components comprise Bi2O3 0.3-1.5 wt%, Co2O3 0.1-0.6 wt%, CaCO3 0.03-0.08 wt% and ZrO2 less than or equal to 0.1 wt% with the total mass percentage of the main components being taken as a standard. The content of Fe2O3, ZnO, NiO and CuO is controlled, the content of the auxiliary components is matched and adjusted, the prepared nickel-zinc-copper ferrite has high saturation magnetic induction intensity, high magnetic permeability, high Curie temperature, low residual magnetic induction intensity and low specific temperature coefficient, and can be better applied to power inductance or common-mode inductance.
Owner:HENGDIAN GRP DMEGC MAGNETICS CO LTD +1