49 results about "Ferromagnetic resonance" patented technology

The invention provides a PT ferromagnetic resonance overvoltage suppression system and method based on graded damping. The system comprises a secondary resonance elimination module, the secondary resonance elimination module comprises a three-stage damping branch circuit which is connected in series with an open triangle of a voltage transformer, the three-stage damping branch circuit comprises a first current-sensitive resonance eliminator, a second current-sensitive resonance eliminator and a fixed resistor which are connected in parallel, and a branch circuit of the first current-sensitive resonance eliminator is connected in series with a first switch; a branch of the second flow-sensitive resonance eliminator is connected in series with a second switch, and a branch of the fixed resistor is connected in series with a third switch; the fan is used for carrying out air cooling on the first flow-sensitive resonance eliminator, the second flow-sensitive resonance eliminator and the fixed resistor; and the control module is used for controlling on or off of the first switch, the second switch and the third switch. Resonance early recognition is achieved through transient energy comprehensive criteria, three-level damping dynamic switching and fan intelligent temperature control are combined, and the three core problems of response lag, insufficient heat dissipation and weak self-adaption in ferromagnetic resonance suppression are solved.

An acoustically driven ferromagnetic resonance (ADFMR) device has a piezoelectric element comprised of piezoelectric material, first and second electrodes arranged in a vertical stack with the piezoelectric element to activate the piezoelectric element to generate an acoustic wave, a radio frequency voltage source electrically connected to the first electrode, a magnet comprised of a magnetostrictive material to receive the acoustic wave, the magnet being in the vertical stack with the first and second electrodes and the piezoelectric element, wherein the acoustic wave resonates at a ferromagnetic resonance of the magnetostrictive material, and a readout circuit to detect a change in the acoustic wave by detecting g one of an output voltage amplitude, a change in impedance or a reflection of the acoustic wave in the magnet to measure an unknown magnetic field in which the ADFMR device resides and as experienced at the magnetostrictive element.

The invention discloses a PT ferromagnetic resonance adaptive collaborative suppression method and system, and the method comprises the steps: sampling a voltage signal, a current signal and a PT secondary side voltage signal monitored by a high-voltage end sensing unit in real time, and calculating a primary side voltage change rate and harmonic content; comparing the calculated primary side voltage change rate and harmonic content with corresponding preset thresholds, controlling to input a neutral point reconstruction unit, and destroying resonance conditions by changing neutral point grounding impedance; after the neutral point reconstruction unit works, the input energy feedback unit is controlled and used for absorbing resonance energy; and when it is detected that the resonance threat is eliminated, the neutral point reconstruction unit and the energy feedback unit are controlled to be turned off in sequence, and active cooling of the high-voltage end sensing unit is started by using residual energy in the energy feedback unit. According to the method, by monitoring the voltage change rate and the harmonic content in real time, a neutral point is rapidly triggered to reconstruct and damage resonance, energy is absorbed and fed back through an energy feedback unit, and finally system safety recovery is achieved.

The invention provides a risk prediction and cooperative defense system and method for ferromagnetic resonance of a power grid. The data acquisition module is used for acquiring electrical quantity data and switch state data of a plurality of nodes of the whole network in real time; the data analysis module is used for analyzing the electrical quantity data through a preset first prediction model to calculate a first risk characteristic value, and analyzing the switch state data through a preset second prediction model to calculate a second risk characteristic value; the feature fusion module is used for calculating the risk probability and grade of the magnetic resonance of the starting iron by fusing the first risk feature value and the second risk feature value; and the early warning and execution module is used for generating early warning information and a self-adaptive regulation and control strategy according to the calculated risk probability and grade of the ferromagnetic resonance, and sending out a corresponding alarm according to the generated early warning information and the self-adaptive regulation and control strategy. Through multi-source data fusion analysis, advanced prediction of the ferromagnetic resonance risk is realized, and passive response is changed into active defense.

The invention relates to the technical field of electromagnetic measurement and state monitoring, and discloses a global state sensing system and method for an electromagnetic voltage transformer. The technical problems that in the prior art, data robustness is insufficient and actual working condition changes of a power grid are difficult to adapt due to the fact that accurate resonance circuit parameters are depended and a single calculation path is adopted are solved. According to the method, ferromagnetic resonance phenomena under various faults are simulated based on electromagnetic transient simulation, phenomenon data are obtained, and influence factors are analyzed to obtain influence rule data. And taking the rule data as input, and adopting a comprehensive solving method combining programming calculation, system structure chart calculation and electromagnetic transient software simulation to obtain a high-reliability state quantity time sequence. Based on the time sequence, a nonlinear model which takes loss into account and does not depend on precise resonant circuit parameters is derived, and explicit mathematical functions of primary current and transient overvoltage of the voltage transformer are obtained.

The application discloses a kind of single crystal resonator ferromagnetic resonance line width fast screening device for magnetic tuning filter, belong to microwave component testing field, the testing device includes resonator (1), resonator (2), adjustable DC power supply (3) and vector network analyzer (4);Wherein, the resonator (2) after orientation is placed in resonator (1), the resonator (1) is connected with vector network analyzer (4) and adjustable DC power supply (3) respectively by data line, the application also discloses the method for using the above device to carry out single crystal resonator ferromagnetic resonance line width fast screening for magnetic tuning filter;The screening device of the application can realize the screening of one sample in 30 seconds, and the testing accuracy is good, can meet the demand of batch product screening test, is favorable for improving the tuning efficiency of magnetic tuning filter, reduces production cost, has very strong practical value.

Methods and apparatuses (devices, methods, etc.) for determining gestures, e.g., hand gestures, from a wrist and / or forearm worn array of magnetometers. These methods and apparatuses may use a trained machine-learning agent to identify gestures from magnetic signals that have been preprocessed to optimize gesture detection. The trained machine learning agent may apply a hierarchical classification that first identifies a first category of gestures from a second category of gestures and then classifies between the individual gestures within each category. The methods and apparatuses described herein may be of particular use with acoustically driven ferromagnetic resonance (ADFMR) sensors.

The invention relates to the technical field of ferrite single-crystal materials, in particular to a treatment method for improving the ferromagnetic resonance line width of spinel NiZn ferrite single-crystal pellets, which comprises the following steps: annealing the spinel NiZn ferrite single-crystal pellets under the conditions of high oxygen pressure and high temperature, slowly cooling to room temperature, and releasing the pressure after the annealing is finished, thereby obtaining the spinel NiZn ferrite single-crystal pellets. According to the method, the NiZn ferrite single crystal pellets are subjected to annealing treatment by adopting a high-oxygen-pressure high-temperature annealing treatment process, the pellet processing stress can be released under the condition of inhibiting Zn element volatilization, the ferromagnetic resonance line width of the NiZn ferrite single crystal pellets can be effectively reduced, and subsequent pellet surface polishing treatment is also facilitated.

The application relates to a quick-disassembly waveguide structure for testing the line width of ferrite ferromagnetic resonance, belonging to the field of microwave and millimeter wave band magnetic material parameter testing. The quick-disassembly waveguide structure comprises a main waveguide tube and a quick-disassembly resonant cavity, and the main waveguide tube comprises a first rectangular waveguide, a second rectangular waveguide, a connecting bridge, a waveguide flange and a positioning pin. The quick-disassembly waveguide structure for testing the line width of ferrite ferromagnetic resonance is characterized in that the rectangular waveguide, the waveguide flange, the connecting bridge and the coupling sheet of the resonant cavity are integrally connected to form the main waveguide tube, the quick-disassembly resonant cavity is placed in the gap formed by the connecting bridge, and the quick-disassembly resonant cavity is achieved; the sample loading method of 'filling medium in the cavity and loading the sample through the medium sheet' is adopted, and the loading problem of the 30GHz and above millimeter wave band ferrite FMR test sample is solved.

The invention discloses a method for synthesizing a ZnFe2O4 photocatalyst based on ferromagnetic resonance absorption effect mediation. The synthesis method comprises the following steps: dissolving Zn (NO3) 2.3 H2O and Fe (NO3) 3.9 H2O in deionized water, and stirring to obtain a mixed solution; adding a NaOH solution to adjust the pH value; continuously heating and stirring, filtering after low-power short-time microwave heating, washing with water until the pH value of supernate is 7, and naturally drying; and continuously calcining the dried product, and then carrying out low-power short-time microwave heating to obtain the ZnFe2O4 photocatalyst with the specific surface area of 49.3-50.6 m < 2 > / g, the visible light absorption range of 580 nm and the saturation magnetization of 46.5-47.33 emu / g. The obtained photocatalyst is large in specific surface area, high in visible light absorption capacity, low in photogenerated charge recombination efficiency, easy to separate and recycle, high in photocatalytic capacity and capable of effectively removing norfloxacin in wastewater.

A method for preparing high-dielectric, moderately saturated magnetized yttrium iron garnet ferrite belongs to the field of microwave and magnetic materials technology. This invention utilizes a method that substitutes the dodecahedral Y-site in the garnet structure. 3+ Octahedral and tetrahedral Fe 3+ The formulation and secondary granulation process result in a material with moderate saturation magnetization (1050G < 4πMs < 1250G), suitable for low-frequency microwave ferrite devices. It also possesses high dielectric constant ε' > 20, low ferromagnetic resonance linewidth ΔH ≤ 24Oe, and low dielectric loss tanδ. ε <1×10 ‑4 This can reduce the design size of the device, which is beneficial for the miniaturization and weight reduction of microwave ferrite devices.

The application discloses a 10KV resonance identification and harmonic elimination method, comprising the following steps: S1, collecting open delta voltage, and using different scales to carry out wavelet decomposition on the collected open delta voltage to extract signal components of different frequency bands; S2, establishing a signal component maximum absolute value M matrix according to the extracted signal components of different frequency bands; S3, comparing the signal component maximum absolute values of the frequency bands to complete amplitude, frequency identification and harmonic identification of waveform singularity; and S4, calculating to obtain a harmonic elimination condition and a damping resistance. The application can accurately identify resonance and select a harmonic elimination damping resistance, and has sensitivity and reliability for eliminating ferromagnetic resonance of a voltage transformer.

A method for preparing high dielectric constant, small linewidth yttrium iron garnet ferrite material belongs to the field of ferrite material preparation technology. This invention utilizes the dodecahedral Y-axis in the garnet structure... 3+ octahedral Fe 3+ Instead of using a traditional method, this invention employs a two-stage pre-calcination process and a three-stage ball milling process (low speed followed by high speed), requiring only three ball milling operations, one granulation operation, and one sintering operation to produce yttrium iron garnet ferrite materials. The two-stage pre-calcination process results in better powder activity, a higher degree of solid-state reaction completion during sintering, and superior material properties. The three-stage ball milling process, using a low-speed followed by a high-speed process, enhances the particle size uniformity of the milled powder. The resulting ferrite exhibits a high dielectric constant ε' > 20, a low ferromagnetic resonance linewidth ΔH ≤ 25Oe, and a low dielectric loss tanδ. ε <1×10 ‑4 .

Described herein are methods and apparatuses to provide accurate measurement of relatively small magnetic fields under ambient conditions while being worn on an ambulatory subject. These methods and apparatuses may allow accurate and reliable detection of biomagnetic fields from organs such as the brain, heart, and muscles, using a magnetometer, and in particular, using an Acoustically Driven Ferromagnetic Resonance (ADFMR) sensor. These methods and apparatuses may incorporate one or more of: a synthetic gradiometer, flexible and / or thin-film / foil shielding, and / or denoising.

The application discloses a kind of time and space resolution GHz spin precession detection method and system, comprising: obtaining the static synchronous radiation XMCD signal of the magnetic sample to be measured and the information of ferromagnetic resonance under specific frequency;High-frequency microwave signal is extracted from the accelerator center main microwave source and is pulsed with the same frequency (with the same frequency with the synchronous radiation X-ray pulse signal), phase delay, low-frequency modulation, power gain and microwave frequency multiplication processing after inputting plane waveguide to excite sample and generate ferromagnetic resonance;At the same time, the synchronous radiation X-ray is incident on the magnetic sample through waveguide hole, and the photoluminescence signal of the magnetic sample under different phase delays of high-frequency microwave signal relative to X-ray pulse is measured, to obtain dynamic spin precession signal;Finally, change detection position and repeat, realize spatial resolution.The application designs the detection method of system module, utilizes the advantages of synchronous radiation X-ray pulse time structure and small size light spot, realizes time and space resolution GHz spin precession detection.

Magnetic storage unit comprising: a magnetic tunnel contact column comprising a tunnel barrier layer (22) arranged between a synthetic antiferromagnetic reference layer structure (10) and a magnetic free layer (24), wherein the synthetic antiferromagnetic reference layer structure comprises a polarizing magnetic layer (20) magnetically interacting with a stack of magnetic reference layers comprising a first magnetic reference layer (16) and a second magnetic reference layer (12), wherein the polarizing magnetic layer (20) forms an interface with the tunnel barrier layer (22) and has a ferromagnetic resonant frequency peak substantially overlapping a ferromagnetic resonant frequency peak of at least the first magnetic reference layer (16).

Spin diode device (100; 300; 500) configured to detect a microwave signal oscillating at a first target oscillation frequency or a second target oscillation frequency, the spin diode device (100; 300; 500) comprising: a magnetic tunnel contact stack (150) arranged between a lower electrode (130) and an upper electrode (140), the magnetic tunnel contact stack (150) comprising: a lower magnetic layer (102) with a lower magnetic film (312); a tunnel barrier layer (104) above the lower magnetic layer (102), wherein the tunnel barrier layer (104) comprises an insulating material; and an upper magnetic layer (106) above the tunnel barrier layer (104), wherein the upper magnetic layer (106) comprises an upper magnetic film (322); wherein each of the lower magnetic film (312) and the upper magnetic film (322) has a perpendicular magnetic anisotropy, wherein the lower magnetic film (312) comprises a first strength of perpendicular magnetic anisotropy corresponding to a first natural ferromagnetic resonance frequency, wherein the first natural ferromagnetic resonance frequency corresponds to the first target oscillation frequency, wherein the upper magnetic film (322) comprises a second strength of perpendicular magnetic anisotropy corresponding to a second natural ferromagnetic resonance frequency, wherein the second natural ferromagnetic resonance frequency corresponds to the second target oscillation frequency, where the second strength of perpendicular magnetic anisotropy differs from the first strength of perpendicular magnetic anisotropy, and where the second natural ferromagnetic resonance frequency differs from the first natural ferromagnetic resonance frequency.

The application discloses a kind of vector magnetic sensor based on acoustic wave driven ferromagnetic resonance, including processing component and two groups of interdigital transducing components, each group of interdigital transducing components includes input interdigital transducer and output interdigital transducer, and a certain space distance is arranged between input and output interdigital transducer in each group of interdigital transducing components to form delay line structure, two delay line structures are crossed same and are set at 45 ° angle, and magnetic film made of ferromagnetic material is grown in the space distance of two delay line structures, and the direction of the magnetic field sensed by two delay line structures is-45 ° with the direction of acoustic wave propagation in the delay line structure.The processing component is analyzed by collecting the electrical signal of input and output interdigital transducer in two groups of interdigital transducing components, and the size of the magnetic field measured by each delay line structure is obtained, and then the size and direction of external magnetic field are obtained by vector synthesis.The application can simultaneously detect the direction and size of external magnetic field.

The application discloses a high-flux probe type magnetic sensor full-band test system based on a matrix switch and belongs to the technical field of magnetic sensor testing, which comprises a task queue management module, a switching protection and air window control module, a stability detection and judgment module, a full-band test and quality control module and a spin torque ferromagnetic resonance analysis module. The application solves the technical problems in the prior art that due to the limited low-temperature or strong magnetic field test environment space, the sample test interval is deep and the space is compact, the traditional manual sample replacement, probe adjustment and multi-sample switching operation are extremely difficult to implement, it is difficult to balance the automation and high-precision requirements, and when the matrix switch switches the signal path, the dynamic adjustment of physical and electrical parameters easily leads to signal instantaneous distortion and unstable high-frequency measurement, thereby affecting the test result precision and reliability.

The utility model belongs to the technical field of voltage mutual inductance, and particularly relates to a voltage mutual inductance device with a cable plug type independent power supply. A voltage transformer for a power supply comprises an independent voltage iron core and an independent power supply primary coil wound on the independent voltage iron core; a phase iron core, a B phase iron core, a C phase iron core, and an A phase primary coil, a B phase primary coil and a C phase primary coil respectively wound on the A phase iron core, the B phase iron core and the C phase iron core are physically separated, the five transformers form a 5PT integrated structure through epoxy resin, and ferromagnetic resonance is effectively inhibited by combining iron core material optimization and anti-resonance design. Compact design is achieved, and narrow spaces such as a ring main unit are adapted. And the safety is improved. Magnetic field interference is avoided and metering precision is ensured.

Acoustically driven ferromagnetic resonance (ADFMR) sensor apparatuses may be tuned by the application of a tuning voltage. A tunable ADFMR sensor apparatus may include one or more tuning electrical contacts that are configured to adjust the output of the ADFMR magnetic field sensor, e.g., by applying a voltage to adjust a magnetic property of the multiferroic magnetic material of the ADFMR magnetic field sensor. Tuning may be performed in real time, or near-real time, based on an output of the ADFMR magnetic field sensor. In some cases tuning may include field zeroing and / or adjusting the range of field measurements.

The patent discloses a high-dielectric YIG ferrite material and a preparation method thereof, and belongs to the technical field of microwave ferrite materials 1.65‑x‑y Bi 1.35 Ca x+ y Zr x Sn y Fe 5‑x‑y O 12 , wherein x=0.25-0.65, and y=0-0.5.The garnet-type microwave ferrite material has high dielectric constant and medium power characteristics, and has excellent electromagnetic performance; the relative dielectric constant epsilon is about 27, the dielectric loss tan epsilon is less than or equal to 8*10 ‑4 , the spin wave line width Delta Hk is greater than or equal to 9 Oe, the ferromagnetic resonance line width Delta H is less than or equal to 105 Oe, and 4pi Ms is greater than or equal to 1900 Gs; the garnet-type microwave ferrite material can effectively reduce the design size of a microwave circulator device and meet the miniaturization requirement.

The present application belongs to the field of electronic information functional materials and microelectronic devices, and relates to a microwave ferrite material, and particularly provides an LTCC high-curie-temperature NiZn ferrite substrate material and a preparation method thereof, to solve the defects of the existing low-temperature sintering NiCuZn ferrite substrate material, such as low curie temperature, high microwave magnetic loss and dielectric loss, low saturation magnetization and low dielectric constant; the present application uses Cu-doped high Ni / Zn ratio NiZn ferrite as a main material, and uses Bi2O3-CuO composite eutectic mixture as an auxiliary material, and the two are low-temperature co-fired to form a substrate material, which not only has a low sintering temperature (about 900 DEG C), but also has excellent microwave characteristics: high curie temperature (about 302 DEG C), low ferromagnetic resonance line width (about 100 Oe), low dielectric loss (loss tangent value about 8*10 ‑4 ) and high saturation magnetization (about 4959 Guass), which not only meets the requirements of the LTCC process, but also has excellent magnetic properties of the key substrate material required by the microwave ferrite device.

The application provides a kind of portable experimental device for measuring ferromagnetic resonance linewidth angle dependence, including base and the top of vertical hydraulic rod in the center of base is movably connected with goods table through spherical connecting seat;The bottom surface of goods table is fixed with driven adjusting mechanism, top adjusting mechanism includes circular ring, arc sleeve and first connecting rod, the base is also provided with driving adjusting mechanism, bottom ring is rotatably connected in outer cylinder, the bottom of bottom ring is fixed with circular gear plate, the inside of base is also fixed with driving motor, the output shaft of driving motor is fixed with driving gear, and the circular gear plate between driving gear is meshed connection, the bottom ring is rotatably connected with rotating ring, the outer of rotating ring is fixed with second connecting rod, and the second connecting rod and the first connecting rod are installed with inclined hydraulic rod.The height and rotation angle of goods table can be adjusted by driving adjusting mechanism and driven adjusting mechanism, which is beneficial to the accurate measurement.

The present application relates to the field of low-voltage power distribution, in particular to a low-voltage ferromagnetic resonance elimination device and method, which is composed of a power module, a signal acquisition module, a main control module, a resonance elimination module and a man-machine interaction module. The input end of the power module is connected to 220V mains, and the output end of the power module is connected to the signal acquisition module, the main control module and the man-machine interaction module to supply power to the three modules. The input end of the signal acquisition module is connected to the PT open delta to acquire PT zero sequence voltage and zero sequence current. The output end of the signal acquisition module is connected to the input end of the main control module. The main control module determines whether resonance occurs and the resonance type through algorithm and logical operation. One end of the output end of the main control module is connected to the input end of the resonance elimination module to eliminate resonance when resonance occurs. The other output end is connected to the man-machine interaction module to display relevant information of resonance in real time, thereby solving the problems of incomplete elimination of resonance by existing resistance resonance elimination, computer resonance elimination crash and long-time PT short circuit.

The invention discloses a resonance monitoring method based on a secondary resonance elimination device, and relates to the technical field of resonance elimination devices, and the method comprises the steps: obtaining historical resonance information and a preset trigger voltage threshold value; based on the historical resonance information, acquiring a plurality of trigger voltage values which resonate before reaching a trigger voltage threshold value; generating a correction voltage value based on the plurality of trigger voltage values; replacing the trigger voltage threshold value with the correction voltage value; and acquiring an actually measured voltage value of the open triangle, and if the actually measured voltage value reaches the corrected voltage value, generating a zero-sequence voltage analysis instruction. The application has the effect of reducing the influence of the ferromagnetic resonance phenomenon on lines and equipment.

The application discloses a PT ferromagnetic resonance self-adaptive cooperative suppression method and system, comprising the following steps: monitoring voltage signals, current signals and PT secondary side voltage signals of a real-time sampling high-voltage end sensing unit, calculating a primary side voltage change rate and harmonic content; comparing the calculated primary side voltage change rate and harmonic content with corresponding preset threshold values, controlling the input of a neutral point reconstruction unit, and destroying the resonance condition by changing the neutral point grounding impedance; after the neutral point reconstruction unit works, controlling the input of an energy feedback unit for absorbing resonance energy; when detecting that the resonance threat is eliminated, controlling the neutral point reconstruction unit and the energy feedback unit to be turned off in sequence, and starting active cooling of the high-voltage end sensing unit by using the remaining energy in the energy feedback unit. The method can realize system safety recovery by monitoring the voltage change rate and harmonic content in real time, quickly triggering the neutral point reconstruction to destroy the resonance, and absorbing and feeding back the energy by using the energy feedback unit.

The application belongs to the technical field of generator manufacturing, and particularly relates to a resonant generator with adjustable inductance. The saturated inductance method is applied to install a stator permanent magnet on the yoke or the slot bottom of a stator, the magnetic field of the permanent magnet passes through the pole teeth and pole shoes to form a magnetic circuit, when the rotor rotates, the magnetic field of the rotor with cross magnetic poles is continuously and alternately attracted and repelled with the magnetic field of the pole shoes and pole teeth, the magnetic flux of the pole teeth is automatically, periodically and cyclically changed, thereby the inductance of the coil with the pole teeth as a magnetic core is automatically, periodically and cyclically changed, the mutual inductance resonance and coupling resonance of the coil are generated, and the ferromagnetic resonance is automatically excited. Compared with the prior art, the application has the beneficial effects that the inductance of the coil is automatically and periodically adjusted by the saturated inductance method, the mutual inductance resonance and coupling resonance of the coil are generated, the ferromagnetic resonance is automatically excited, the generator operates in the ferromagnetic resonance state, thereby the rotational magnetic resistance of the rotor is reduced, the magnetic force of the permanent magnet is led out, and the efficiency of the generator is greatly improved.

Systems and methods are provided for fabricating an assembly with a controllable magnetic state and ferromagnetic resonance. A layer of twisted bilayer graphene is positioned in contact with a transition metal dichalcogenide to form a structure with an interface between the twisted bilayer graphene and the transition metal dichalcogenide. Energy is applied to the interface to adjust one of a magnetic state associated with the interface and a ferromagnetic resonance associated with the interface.

A security ink composition comprising at least one non-luminescent undoped Y3Fe5−xMxO12-based pigment, wherein x fulfils the condition 0≤x≤1.25; M is selected from a group consisting of aluminum, gallium or calcium and mixtures thereof, and wherein an applied, preferably printed, at least one machine-readable security feature derived from said security ink composition, after drying and / or curing, has an integrated magnetic susceptibility of at least about 200×10−12m3 and presents a ferromagnetic resonance (FMR) signature for authentication purposes. A method for authentication of a machine-readable security feature derived from the security ink composition.