108 results about "Magnetic parameter" patented technology

The invention discloses a high-precision power supply output correction method based on a digital pre-distortion technology, and relates to the technical field of power electronics, and the method comprises the steps: integrating an electricity-heat-magnetism real-time combined observer, and inputting parameters including a power supply output voltage, a current, a power device junction temperature, a magnetic element surface temperature, an environment temperature, and an input voltage ripple; using a hierarchical memory depth pre-distortion compensator to generate an anti-phase pre-distortion signal containing long time domain thermal constant compensation and short time domain capacitance energy storage compensation based on modeling engine output; based on a double-ring adaptive updating module, an inner ring updates electrical parameters, including on resistance and dead time, by taking a switching period as a reference, and an outer ring updates thermomagnetic parameters, including thermal resistance and a magnetic core saturation point, in a minute-level period; and the DAC is connected in series with a pre-distortion signal output end through an anti-interference execution channel, and comprises a noise shaping DAC and a driving stage for delay matching. According to the invention, through an electric-thermal-magnetic three-field combined observation architecture, the limitation of traditional single physical field monitoring is broken through.

The embodiment of the invention provides a transformer loss monitoring method and a transformer loss monitoring system, and the monitoring method comprises the steps: dynamically updating winding resistance, excitation reactance and iron core magnetic conductivity according to an electromagnetic parameter and a temperature parameter in a state vector space through employing a complex frequency domain parameter identification algorithm which introduces a fusion expansion Cole-Cole model; the no-load loss and the load loss are decoupled through an improved all-electric difference method, the dynamically updated excitation reactance and the iron core magnetic conductivity are used for decoupling the no-load loss, and the dynamically updated winding resistor is used for decoupling the load loss; and taking the decoupled loss data and the associated parameters in the state vector space as the input of an LSTM-Transform hybrid model loaded on the edge calculation module, and predicting and outputting the load loss trend in the future time period. According to the transformer loss monitoring method, the real-time performance, the accuracy and the adaptability of transformer loss monitoring are improved.

The invention discloses a transient electromagnetic and magnetic method data joint inversion method. The method comprises the following steps: acquiring transient electromagnetic observation data and magnetic method observation data; converting the transient electromagnetic observation data into transient electromagnetic moment data; based on the transient electromagnetic moment data and the magnetic method observation data, a joint inversion objective function is constructed, and the joint inversion objective function comprises a data fitting residual term and a model constraint term; performing parameter coupling on the model constraint term by using a multivariate Gaussian mixture model to obtain a coupled model constraint term; and combining the data fitting residual term and the coupled model constraint term into a final objective function, and minimizing the final objective function through an optimization algorithm to obtain an electrical parameter and a magnetic parameter of the underground medium. According to the method, transient electromagnetic and magnetic method data joint inversion is realized, the problem of low three-dimensional inversion calculation efficiency is solved by introducing transient electromagnetic moment, and electrical and magnetic parameters are coupled by utilizing rock physics constraint, so that the inversion result is more accurate, and the structure is more consistent.

The invention relates to the technical field of 8G, and discloses a nuclear fusion plasma real-time control method and system based on a quantum neural network and 8G communication. The method comprises the following steps: transmitting plasma multi-dimensional electromagnetic parameters at a rate greater than or equal to 1Tbps through an 8G terahertz communication network; quantum dimension reduction (the dimension compression ratio is greater than or equal to 98%) and classical time sequence prediction are executed at the edge quantum computing nodes; a control instruction is transmitted to the superconducting magnet array through the photon integrated interface, so that the adjustment of a magnetic field smaller than or equal to 1nm is realized; physical layer quantum encryption is adopted to guarantee communication security, and the secret key distribution rate is larger than or equal to 20 Mbps.

The invention provides an electromagnetic transient simulation method and system for a magnetic valve type current transformer, and relates to the technical field of power system simulation, and the method specifically comprises the steps: collecting electromagnetic, magnetic field, control and environment data, extracting a flux density peak value, a flux density harmonic distortion rate and a current harmonic distortion rate, and constructing monitoring feature data; constructing a data prediction model, dynamically predicting electromagnetic parameters at the next moment, obtaining electromagnetic data, a flux density peak value, a flux density harmonic distortion rate and a current harmonic distortion rate correction value, performing electromagnetic transient simulation through a finite element-circuit coupling model, calculating an amplitude deviation rate and a phase deviation rate, and performing current harmonic distortion rate correction. And generating a running state comprehensive coefficient to judge the running state of the current transformer. Through multi-dimensional data acquisition, time sequence dynamic modeling and coupling simulation, the problems of poor adaptability of fixed parameters, insufficient time sequence characteristic capture and low simulation precision are solved, and the saturation characteristic simulation precision, the transient prediction accuracy and the secondary side current simulation precision are remarkably improved.

The invention discloses a peripheral nerve stimulation threshold prediction method of a magnetic resonance gradient coil and application thereof. The method comprises the following steps: firstly, designing a reference coil group with differentiated electromagnetic parameters based on a target gradient coil space structure; then combining a high-precision virtual human body anatomical model and an electromagnetic-neurodynamics coupling model, calculating the induction electric field distribution and stimulation threshold of each coil, and positioning sensitive neuron nodes; expressing a stimulation function as a weighted sum of a local magnetic vector potential component, constructing a linear equation set, and solving an optimal coefficient by adopting a least square method; and finally, establishing a linear regression model of a stimulation function and a threshold reciprocal, and defining a prediction function based on a local field. The prediction method provided by the invention has both calculation efficiency and prediction precision, can further derive a magnetic resonance coil peripheral nerve stimulation threshold curve for real-time evaluation of stimulation risks in imaging scanning, and can also introduce a coil design framework to realize electromagnetic optimization design of a high-threshold gradient coil.

The invention provides a method for plasma bombardment energy distribution detection and life prediction of a silicon carbide part, and belongs to the technical field of semiconductor processing based on deep learning. The method comprises the following steps: firstly, arranging a magnetic probe array to obtain local electromagnetic parameters, and obtaining plasma luminescence characteristics by using optical imaging and spectrum acquisition equipment; preprocessing the acquired data to obtain multi-source fusion features; designing an energy distribution reconstruction framework based on a generative adversarial network, wherein a generator is used for deducing a three-dimensional energy distribution field of plasma; and inputting the three-dimensional energy distribution field time sequence characteristics into a bombardment dynamic characteristic modeling time sequence depth network, establishing a nonlinear mapping relation between energy distribution and material aging, further obtaining life prediction parameters, and finally obtaining the remaining service life of the silicon carbide part. According to the method, a complex degradation mechanism can be reflected more accurately, and the precision and robustness of life prediction are remarkably improved.

The invention relates to the technical field of simulation modeling analysis, in particular to a simulation modeling analysis method applied to electromagnetic fluid of an alternating current contactor, which comprises the following steps: acquiring armature displacement data in real time through a displacement sensor, and constructing a dynamic mapping relation table containing hysteresis compensation coefficients; dynamically correcting the air gap permeability based on the displacement data and the compensation coefficient, generating an electromagnetic field dynamic coupling boundary condition, and realizing real-time matching of magnetic parameters and mechanical motion; in fluid field simulation, a deformable sub-grid nesting technology is adopted, elastic deformation control is carried out on grids in an electric arc area in combination with a displacement change rate, the influence of magnetic field distortion on the grids is synchronously corrected by associating hysteresis compensation coefficients, and the coupling problem of electric arc dynamic deformation and hysteresis nonlinearity is solved; and meanwhile, a non-arc region is fixed by utilizing a main grid topology keeping module, a deformation sensitive region is screened to execute local grid recombination, and high-precision dynamic simulation of an arc severe deformation region is realized on the premise of ensuring the calculation stability.

The invention discloses a grounding coplanar waveguide with low radiation loss and high signal uniformity, and belongs to the field of magnetic parameter measurement. The grounding coplanar waveguide comprises a bottom metal grounding layer, a medium substrate, a grounding through hole, a signal line, a split signal line and two side metal grounding layers. The dielectric substrate is arranged above the metal grounding layer, two-side metal grounding layers are arranged above two sides of the dielectric substrate, the two-side metal grounding layers are respectively provided with more than two columns of grounding through holes to form a through hole array, a split signal line is arranged in the middle position above the dielectric substrate, and two ends of the split signal line are respectively connected with signal lines. One end of the split signal line is connected with a signal input end, and the other end is connected with a signal output end; the bottom metal grounding layer and the two side metal grounding layers are connected through grounding through holes. According to the invention, the phenomenon of broadening of a test curve caused by non-uniform distribution of a surface magnetic field is avoided, so that the test precision is improved to a great extent, and the radiation loss at a high-frequency position of the grounded coplanar waveguide is reduced.

The invention relates to a high-temperature irreversible magnetic flux loss proportion and residual magnetism prediction method, belongs to the field of high-temperature-resistant permanent magnets, and is particularly suitable for predicting irreversible magnetic flux loss proportion and residual magnetism generated when high-temperature magnets such as SmCo and the like are subjected to high-temperature pre-stabilization treatment. The core of the method is as follows: the irreversible magnetic flux loss proportion and the residual magnetism of a magnet element subjected to high-temperature pre-stabilization treatment at a specific temperature can be accurately calculated only by inputting three key parameters of the geometric shape of the magnet, the knee-point magnetic field intensity with international standards and the residual magnetism, and the method is simple and efficient in calculation process; a reliable and easily-obtained magnetic parameter basis is provided for accurate design of a high-temperature permanent magnet magnetic circuit, and the design efficiency and reliability are remarkably improved.

The invention relates to the technical field of low-temperature environment simulation and material characteristic test, in particular to a high-speed rail traction system fault diagnosis method based on electromagnetic parameter fusion, which is used for solving the problems of material electromagnetic characteristic test distortion and fault diagnosis algorithm verification deficiency in a high and cold environment. The method comprises the following steps: constructing a multi-physical field coupling test environment, simulating temperature cycle and humidity sudden change working conditions from-50 DEG C to + 80 DEG C, and synchronously acquiring dynamic parameters of resistivity, dielectric loss and magnetic conductivity; according to the method, the limitation of a traditional static test is broken through, the real representation of the material performance degradation rule is realized, a closed-loop verification system of laboratory and field data is constructed, and the performance of the material is verified. The accuracy and environmental adaptability of fault diagnosis in a high and cold environment are remarkably improved, and reliable guarantee is provided for safe operation of a traction system under an extreme working condition.

The invention provides a gyroscope-assisted geomagnetic calibration method of layered parameter adjustment EKF, and relates to the technical field of sensor data processing and attitude calculation. According to the method, under a traditional EKF framework, a hierarchical selection mechanism for a process noise control parameter alpha and an observation noise adjustment parameter beta is introduced, a historical attitude quaternion and a geomagnetic observation value are subjected to statistical analysis through a sliding window mechanism, a mean value and a variance are calculated respectively, expert voting is carried out according to the deviation degree, and a process noise control parameter alpha and an observation noise adjustment parameter beta are obtained; parameters alpha and beta are dynamically adjusted according to the voting condition, and then the parameters alpha and beta act on a prediction noise covariance matrix Qk and an observation noise covariance matrix Rk respectively. According to the method, real-time optimization of the filter parameters is realized under the condition of not adding extra hardware and complex calculation, the precision and stability of soft magnetic and hard magnetic parameter calibration are improved, and the method has the advantages of being simple to implement, suitable for embedded deployment, high in external magnetic interference robustness and the like.

This invention discloses a multi-channel electromagnetic induction detection method and system based on uniform magnetic field constraint. A uniform magnetic field is constructed within the detection area of ​​the structure under test. Electromagnetic induction response signals are acquired through multiple channels under the constraint of the uniform magnetic field, and the spatial coordinates of each acquisition channel are marked. The raw electromagnetic induction signals acquired by each channel are preprocessed, including noise reduction filtering, envelope extraction, and amplitude normalization. A deep learning model is then used to extract structural features from the preprocessed multi-channel electromagnetic response signals. Based on the spatial position information of each acquisition channel, magnetic field uniformity parameters, and response characteristics, a channel correlation weight matrix is ​​constructed to describe the spatial consistency and physical coupling relationships between channels. A multi-channel joint optimization model is constructed, and the equivalent electromagnetic parameter distribution inside the structure under test is reconstructed through iterative solution. This invention improves the reliability, repeatability, and engineering applicability of electromagnetic induction detection results.

The invention relates to the technical field of electromagnetic valve manufacturing and quality detection, and discloses an online detection system for the pressing force of a valve element of an electromagnetic valve, and the system comprises a composite magnetic field excitation module, a multi-physical field signal acquisition module, a multi-dimensional feature resolving module and a force value estimation output module. A composite magnetic field is applied to a valve element, and an induced voltage signal, a Hall signal and a temperature signal are synchronously collected; then, three characteristic quantities of harmonic amplitude, instantaneous magnetic field intensity and instantaneous temperature are calculated; and finally, inputting the three characteristic quantities into a preset multi-dimensional mapping model, and calculating to obtain a pressing force estimated value. The invention aims to solve the problem of low measurement accuracy caused by the fact that the existing single electromagnetic parameter detection is easily interfered by temperature and excitation field fluctuation. And through multi-physical field signal fusion and multi-dimensional feature compensation, the influence of disturbance factors is effectively eliminated, and the accuracy, stability and anti-interference capability of online detection are remarkably improved.

This invention belongs to the field of electrical digital data processing technology, specifically relating to a multi-objective optimization method for improving motor torque performance. The method includes: establishing a parameterized model of the motor; extracting geometric harmonic prior features based on the harmonic analysis principle of the motor's air gap magnetic flux density, and using these as a screening criterion to obtain an initial high-quality sample set; constructing a Kriging surrogate model reflecting the mapping relationship between design variables and performance response, introducing an energy efficiency boundary risk function during the construction process; based on the Kriging surrogate model, using a multi-objective optimization algorithm to search for a Pareto front solution set, selecting potential sample points from the Pareto front solution set for simulation verification, and then adaptively updating the Kriging surrogate model until the stopping criterion is met, at which point the target motor design parameters are output. This invention can achieve accurate optimization of electromagnetic parameters by screening samples through geometric harmonic prior features and utilizing the energy efficiency boundary risk function.

The application belongs to the technical field of magnetic parameter measurement, and discloses a device and a calculation method for testing magnetic force in each direction between permanent magnets. The device uses an electric sliding table and a vertical sliding table to construct a three-dimensional motion platform, and collects the magnetic force of a tile-shaped permanent magnet under different spatial displacements in real time through a sensor. The device can not only meet the force testing needs of the inner / outer rotor permanent magnet under the axial, radial and tangential misalignment states, but also can adapt to different sizes of the inner / outer rotor permanent magnet by adjusting the clamp. Meanwhile, the magnetic force calculation method proposed by the application takes the equivalent magnetic charge model under the cylindrical coordinate system as the theoretical basis, and accurately solves the three-dimensional magnetic force of the inner / outer rotor permanent magnet under any spatial relative position through quadruple integration. With the help of the testing device and the calculation model proposed by the application, the precise measurement and theoretical verification of the magnetic force in each direction of the permanent magnet can be realized, the calculation is simple, and the degree of coincidence is high. The testing and calculation method has engineering universality and convenience.

The invention discloses an electromagnetic torque layered modeling method based on magnetic conductance space attenuation characteristics, and relates to the technical field of permanent magnet motors, and the method comprises the steps: building an electromagnetic parameter expression through motor parameters; determining magnetomotive force parameter expressions of an armature and a permanent magnet through motor pole slot cooperation and a winding mode, and thus obtaining magnetomotive force harmonic waves; according to the condition that the number of magnetic field pole pairs in the electromagnetic parameter expression is the same, an armature magnetic field source generating average torque is limited, and an armature magnetomotive force source is determined to modulate the magnetic conductance order; determining air gap space magnetic conductance through conformal transformation; spatial layering and harmonic attenuation law analysis are carried out aiming at air gap space magnetic conductance, electromagnetic layering torque considering space attenuation characteristics is calculated through magnetomotive force harmonic and magnetic conductance harmonic modulation coupling, and weighting is carried out on the electromagnetic layering torque to obtain the total torque of the motor. According to the method, the torque modeling precision of the permanent magnet vernier motor is remarkably improved.

The present invention discloses a method for processing equivalent electromagnetic parameters of reinforced concrete for analyzing the time-domain coupling characteristics of electromagnetic pulse environments. The method first obtains the S parameters of a reinforced concrete wall structure; then, the relationship between the S parameters and the reflection coefficient and transmission coefficient is calculated; then, the relationship between the relative permittivity and relative magnetic permeability and the reflection coefficient and transmission coefficient is calculated; then, the intermediate variables, the reflection coefficient and transmission coefficient, are eliminated to obtain a relationship expressing the relative permittivity and relative magnetic permeability using the S parameters; finally, the obtained equivalent electromagnetic parameters are fitted into a specific, frequency-continuous mathematical polynomial form. The present invention overcomes the multi-valued nature of the equivalent electromagnetic parameter calculation results through imaginary part compensation, and achieves frequency-domain continuous parameter calculation in the frequency band of interest through polynomial fitting. This method can effectively reduce the computational resource consumption of complex reinforced concrete building models, and provides a method for calculating the time-domain electromagnetic coupling response of large-scale buildings to external electromagnetic pulse environments.

The invention discloses a permanent magnet synchronous linear motor optimal current control method based on a magnetic equivalent circuit model, and the method comprises the steps: considering the nonlinear behavior of a motor, building an accurate MEC model suitable for a PMLSM for a stator part, an air gap part and a rotor part through the electromagnetic quantity of the motor, and building an electromagnetic parameter and thrust balance equation; therefore, an accurate motor thrust expression is obtained, and an optimal current control strategy considering thrust accuracy and coil copper loss minimization is further designed based on the motor thrust expression. According to the MEC model and the corresponding optimal current control strategy, the calculation burden can be reduced on the basis that the model precision is ensured, meanwhile, accurate control over the position and thrust is achieved, the optimal current strategy can further reduce copper loss and improve the efficiency of the system, and high research value and application value are achieved.

The invention discloses a low-frequency voltage transformer design method, a low-frequency voltage transformer, a terminal and a medium, and belongs to the field of low-frequency voltage transformers, and the method comprises the steps: S1, obtaining system design input parameters; s2, performing magnetic parameter calculation based on the input parameters; s3, designing an LC compensation network based on the obtained parameters, and calculating resonant frequency; s4, selecting a winding conductor and an insulating material, and designing a structural diagram; s5, constructing a three-dimensional model of the mutual inductor and performing multi-physics field simulation verification; s6, iterative optimization is conducted on the preliminary design according to the simulation result, the design is completed, the mutual inductor comprises a box body, a junction box and an inflation valve are arranged on the side wall of the box body, a pressing ring and an insulator are arranged at the top of the box body, an anti-explosion valve is arranged at the bottom of the box body, and a winding is arranged in the box body; by constructing a set of systematic low-frequency voltage transformer design process, the problems of poor adaptability, low design efficiency and insufficient accuracy of a traditional design method under a low-frequency condition in the prior art are solved.

This application discloses a method and apparatus for obtaining coil electromagnetic parameters. The method includes: obtaining second-level parameters of a superconducting maglev train; the second-level parameters include the levitation force and guiding force characteristics generated by the vehicle and the figure-eight coil, the drag characteristics generated by the vehicle and the figure-eight coil, and the traction force characteristics of the vehicle; determining third-level parameters of the superconducting maglev train based on the second-level parameters; the third-level parameters include the centerline dimensions of the superconducting magnetic poles, the distance between the centerline and the figure-eight coil, the distance between the centerline and the stator coil of the linear motor, the magnetomotive force of the superconducting magnetic poles, the pole pitch of the superconducting magnetic poles, the coil operating temperature, and the overcurrent and over-limit safety margin of the superconducting coil; and determining the coil electromagnetic parameters of the superconducting magnet based on the third-level parameters; the coil electromagnetic parameters include the coil operating current and the coil dimensions of the superconducting magnet. This application provides a modular design method for coil electromagnetic design, which facilitates continuous iteration and optimization between different parameter indicators.

The purpose of this invention is to provide a testing device for the electromagnetic properties of thin film materials based on a re-entrant coaxial resonant cavity, belonging to the field of electromagnetic parameter testing technology for microwave and millimeter-wave materials. The device comprises three parts: a re-entrant coaxial resonant cavity, a sample fixture, and a support base. By placing samples at the locations of strongest electric and magnetic field intensity within the resonant cavity, the complex permittivity and permeability of the thin film material can be measured. The testing of the complex permittivity and permeability of the sample is completed using only one device. Simultaneously, the sample placement gap does not interrupt the electric field lines, thus not affecting the field distribution within the cavity. This allows the device to maintain the high quality factor of the resonant cavity while reducing the cavity volume, concentrating the electric field within the resonant cavity mainly in the capacitively loaded region, improving the testing bandwidth, sensitivity, and accuracy, and reducing the requirements for sample size.

The application discloses a gravity-magnetic-electric comprehensive parameter exploration method for hot dry rock identification, and comprises the following steps: S1, acquiring gravity-magnetic-electric inversion parameters corresponding to a survey area in space, and performing grid processing on the gravity-magnetic-electric inversion parameters; S2, performing standardization processing on the grid inversion parameters; S3, calculating correlation coefficients of the density parameter and the magnetic parameter respectively by taking the resistivity as a main parameter; S4, calculating gravity-magnetic-electric comprehensive parameters; and S5, analyzing and interpreting the gravity-magnetic-electric comprehensive parameters. Through analyzing the gravity-magnetic-electric comprehensive parameters, the hot dry rock identification and delineation can be provided with higher exploration accuracy, so that the problems of low hot dry rock identification accuracy and strong randomness of identification are solved.

The invention relates to a rock ore specimen magnetic parameter measuring device and method for geological exploration, and belongs to the technical field of geological exploration, the rock ore specimen magnetic parameter measuring device comprises a tripod, a measuring device, a mounting box, a mounting plate and a floating member, the top surface of the mounting box is open, the bottom of the mounting box is provided with a first fixing member, the floating member is located in the mounting box, and the tripod is arranged on the mounting plate; the measuring device is arranged on the tripod and used for measuring magnetic parameters of the specimen; the mounting plate is embedded in the top surface of the floating part, a fixing rod is slidably arranged in the mounting plate, and a first driving part for driving the fixing rod to slide is arranged in the mounting plate; a plurality of slideways are formed in the top surface of the mounting plate, the number of the slideways is consistent with that of the tripod kickstands, the slideways are uniformly distributed along the center of the mounting plate, sliding blocks are arranged in the slideways in a sliding manner, the tripod kickstands are inserted into the sliding blocks, and a second driving part used for driving the sliding blocks to slide at the same speed at the same time is arranged on the mounting plate. The method has the advantage of improving the measurement efficiency and precision of the magnetic parameters of the specimen.

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 invention discloses an induction heating optimization method and system based on numerical simulation. The method comprises the following steps: S1, establishing a three-dimensional geometric model comprising an induction coil, a workpiece and a magnetizer; s2, electromagnetic parameters and thermal field parameters are set based on the three-dimensional geometric model; s3, performing grid division on the three-dimensional geometric model; s4, operating an electromagnetic-thermal sequential coupling solver, calculating transient distribution of an electromagnetic field and a temperature field based on the parameters set in S2 and the grids generated in S3, dynamically updating material attributes according to the current temperature field in each time step, and performing iterative solution; and S5, processing the field distribution data obtained by solving in the step S4, generating a visual result and extracting key performance indexes. According to the invention, the distribution of the magnetic field and the temperature field can be accurately optimized, and meanwhile, extremely high heating efficiency, excellent temperature uniformity and excellent process controllability are realized.

The invention provides a spin wave test image denoising method, which is a data processing method provided based on a microwave excitation-electrical detection spin wave technology, and comprises the following steps of: firstly, subtracting original data from data at a maximum magnetic field; secondly, the processed data matrix is divided into a limited number of sub-matrixes, medians under different frequencies in each sub-matrix are obtained to serve as reference signals, final spin wave transmission signals are obtained by subtracting data in the sub-matrixes, and finally spin wave magnetic parameters are obtained through fitting by means of a spin wave frequency formula. Most signals which do not change along with the change of the magnetic field are removed, and the method is suitable for removing background noise of instrument lines and devices in a spin wave transmission experiment and improving the signal-to-noise ratio of data.

The application discloses a preparation method and application of Co@G / CNT nanorod composite material with super-wide electromagnetic wave absorption performance. The preparation of the composite material is as follows: Co and Zn acetate solutions are added into a mixed solution of dimethyl imidazole and CTAB, stirring is carried out at room temperature, a hydrothermal synthesis reaction is carried out on the obtained solution, the synthesized product is washed, dried, and then calcined under Ar / H2 atmosphere, so that the target product is obtained. In the application, the in-situ growth method is used to directly induce the growth of carbon nanotubes on a carbon rod base, the generated carbon nanotubes can form a continuous conductive network, which is beneficial to adjusting the electromagnetic parameters of the material, such as dielectric constant and magnetic permeability, so that effective absorption can be realized in a wider frequency band. The magnetic metal for generating the carbon nanotubes also provides magnetic loss, and the good synergistic effect of the dielectric loss and the magnetic loss of the composite material further improves the wave absorption performance.

The invention relates to the technical field of spaceflight space electric propulsion, in particular to a magnetic reconnection electric thruster electromagnetic topology integrated simulation system which comprises a high-density spiral wave ion source simulation area, an RMF rotating magnetic field simulation area and a discharge chamber model. Wherein the high-density spiral wave ion source simulation area comprises a spiral wave ion source antenna area and a spiral wave ion source steady-state magnetic field area; the RMF rotating magnetic field simulation area comprises a plasma acceleration section steady-state magnetic field area and a rotating field antenna area; the discharge chamber model comprises a discharge model, a magnetofluid model, a particle collision model and a plasma transport model. The whole working process of the magnetic reconnection electric thruster can be simulated, the performance of the magnetic reconnection electric thruster under different electromagnetic parameter combinations can be rapidly predicted, and the problems that an existing spiral wave ion source and an RMF acceleration device electromagnetic field are difficult to match, and interference exists among multiple electromagnetic fields are solved.

The invention provides a lightning stroke transient analysis method and system for a high-voltage power transmission line. The method comprises the following steps: acquiring power transmission line parameters, material electromagnetic parameters and atmosphere lightning stroke channel parameters; acquiring a three-dimensional electromagnetic field partial differential model and performing space-time discretization based on the three-dimensional electromagnetic field partial differential model and a plurality of preset data to acquire electric field intensity, current density and magnetic field intensity; obtaining structural material parameters; acquiring simulation voltage data and simulation current data based on the data and a plurality of preset data; acquiring actually measured data, and calculating a rise time error, a wave crest amplitude error and a high-frequency component amplitude-frequency response error based on the three data; and if the preset convergence condition is met, realizing accurate simulation of the lightning stroke transient process of the high-voltage transmission line. According to the lightning stroke transient analysis method for the high-voltage transmission line, high-precision global simulation can be carried out on the lightning stroke transient process of the high-voltage transmission line, and reliable data support is provided for lightning protection design optimization.