36 results about "Maxwell's equations" patented technology

The invention discloses a macro-micro hybrid simulation method for electrical equipment insulation defect analysis, which comprises the following steps: S1, establishing a gas defect discharge process simulation model, and describing microscopic particle state change and electric field distribution in a gas discharge process through a particle transport equation and a Poisson equation; the method comprises the steps of S1, establishing an electromagnetic propagation process simulation model, and describing the propagation process of an electromagnetic signal generated by gas discharge through a Maxwell equation set, and S3, performing joint simulation on the model, taking equivalent current of gas discharge as an excitation source, simulating propagation of the electromagnetic signal in power equipment through a finite time domain difference method FDTD, and recording a signal value of a receiver. According to the macro-micro hybrid simulation method for analyzing the insulation defects of the power equipment, the insulation defects of the power equipment are accurately analyzed and monitored, important support is provided for state monitoring and maintenance of the power equipment, and digital transformation of the monitoring technology of the power equipment is promoted.

The invention discloses a three-dimensional electromagnetic inverse scattering imaging method of a diffusion model based on physical constraint embedding. The method comprises the following steps: 1, in a specific three-dimensional electromagnetic inverse scattering imaging environment, defining a dielectric constant of an imaging area, arranging a transmitting and receiving antenna array at the periphery, and obtaining scattering field data of a target area for constructing an input and output sample pair of a diffusion model; 2, constructing a diffusion model on the three-dimensional grid space; 3, introducing a physical consistency constraint term based on a Maxwell equation set in the training stage of the diffusion model; and 4, synthesizing the generation loss and the physical constraint loss of the diffusion model, constructing a joint optimization objective function, and carrying out iterative updating on network parameters by adopting an end-to-end back propagation algorithm until the model converges. According to the method, the spatial resolution and continuity of three-dimensional imaging are remarkably improved, the stability and robustness of inverse scattering reconstruction are improved, and the physical consistency is enhanced. And high-precision and interpretable three-dimensional electromagnetic inverse scattering imaging can be realized.

The invention relates to an in-hole transient electromagnetic response characteristic numerical simulation method based on a tunnel three-dimensional geoelectric model and an absorption boundary finite element method, and belongs to the technical field of geophysical exploration. The method comprises the following steps: constructing a tunnel full-space three-dimensional conductivity model; based on a Maxwell equation set, a vector potential and a scalar potential are introduced, a vector control equation of a transient electromagnetic field is derived in combination with Coulomb specifications, first-order absorption boundary conditions are established, and a weak form finite element equation is derived through a Galerkin weighted margin method; generating a global sparse matrix by utilizing spatial discretization and unstructured grid division, and performing iterative solution on the dynamic electromagnetic field by adopting a Newmark time discretization method; and simulating the transient electromagnetic response of geological anomalous bodies with different resistivity and the distance between the geological anomalous bodies and the receiving coil, and analyzing the attenuation characteristic and the geometric gravity center effect to obtain an electromagnetic response rule. The device can accurately simulate the electromagnetic response of abnormal bodies such as aquifers and faults in front of a tunnel face and around drill holes.

The application belongs to the field of transformers, and discloses a linear phase-shifting transformer equivalent circuit modeling and performance parameter obtaining method, analyzes the electromagnetic relationship between the primary side winding and the air gap when the linear phase-shifting transformer is in steady-state operation, and Maxwell equations of the linear phase-shifting transformer; based on the theory of one-dimensional field, the equivalent circuit of the linear phase-shifting transformer is established and solved when the longitudinal edge effect is considered. The performance parameter obtaining method is also disclosed, which comprises: solving the established equivalent circuit model to obtain the resistance and leakage reactance of the primary side winding, the excitation reactance, and the secondary side winding resistance; and calculating the performance parameters of the linear phase-shifting transformer based on the equivalent circuit solving result. The application considers the actual situation of the transformer in electromagnetic analysis, the model is more accurate, the calculation precision is high, the winding loss, efficiency and voltage regulation rate and other performance parameters of the transformer can be quickly and effectively calculated, the application is relatively convenient in actual calculation and analysis, and has high practical value.

This invention discloses a method for predicting electromagnetic radiation from cables. First, a one-dimensional conductor model of the target cable is established in a three-dimensional simulation space, and its axial direction is divided into multiple segments. Current data for each segment is solved using the finite-difference time-domain method. Then, the three-dimensional simulation space is discretized using a Yee grid, and virtual observation points corresponding to actual observation points are determined. Standard electric field and standard magnetic field update equations are established on the Yee grid based on Maxwell's equations. A field-circuit co-simulation process is established, and in each time step iteration, the current data is equivalently coupled to the standard electric field and standard magnetic field update equations to achieve synchronous updates of transmission line current and spatial electromagnetic field. Finally, this process is executed until a preset termination condition is met, and the time-domain electromagnetic field response at the virtual observation points is extracted as the time-domain electromagnetic radiation prediction result. The advantages are high prediction accuracy and high prediction efficiency.

The application relates to the technical field of permeability calculation, and discloses a permeability calculation method for a circular cross-section ferrite magnetic core in a toroidal inductor; when the magnetic field intensity is calculated, high-frequency analysis is carried out based on Maxwell equations, the characteristic that the magnetic field in the circular cross-section ferrite magnetic core in the toroidal inductor is uniform is used, and a virtual variable Bessel equation is derived based on a cylindrical coordinate system, and the magnetic field intensity calculation model is obtained by solving the equation, so that the limitation that the traditional measurement method needs to depend on a measuring device is broken. When the electric field intensity is calculated, the electric field intensity calculation model is obtained based on the relationship between the electric field intensity and the magnetic field intensity in the Maxwell equations. Based on the calculated magnetic field intensity and electric field intensity, the complex power of the toroidal inductor is calculated, and then the permeability prediction model is obtained in combination with an equivalent circuit model. The application is based on theoretical model calculation, is not limited by specific frequency bands and measuring instruments, is also applicable in a high-frequency range, and the predicted permeability is more accurate.

This application belongs to the technical field of hysteresis modeling of ferromagnetic materials, and discloses a method, system, device, and medium for simulating the hysteresis and loss characteristics of magnetic powder cores. The method includes: solving the eddy current field expression inside the metal spherical particles based on Maxwell's equations; multiplying the calculation result of the eddy current field expression by the total number of magnetic powder core particles to obtain the total eddy current loss inside the particles; dividing the surface of the magnetic powder core into equally spaced segments and setting the height of each segment. h Based on the eddy current path conduction coefficient, parameter optimization is performed using the nonlinear least squares method, combined with the skin effect, to determine the expression for the interparticle eddy current field. Based on the total eddy current loss within the particles and the interparticle loss of the metal sphere calculated according to the interparticle eddy current field expression, combined with the Preisach static hysteresis model, a simulation model of the hysteresis and loss characteristics of magnetic powder cores is constructed. This application can simulate the hysteresis and loss characteristics of granular magnetic powder core materials under high-frequency sinusoidal and non-sinusoidal excitation.

This invention proposes a method and system for simulating the vibrational displacement distribution of magnetic particles based on multiphysics coupling, comprising: Step S1: constructing a three-dimensional geometric model containing biological tissue and magnetic particles; Step S2: setting material parameters for each region; Step S3: configuring multiphysics; Step S4: performing mesh generation; Step S5: setting solver parameters; Step S6: using the finite element method to solve the force of the magnetic field on the magnetic particles in Maxwell's equations and describing the magnetic field distribution in the magnetic particle region; Step S7: using the magnetic force obtained in Step S6 as a load, inputting it into the solid mechanics field module, and solving the vibrational displacement distribution in the magnetic particle region based on the wave equation. Furthermore, the system of this invention includes: a three-dimensional geometric model group, a material library, a mesh module, and a multiphysics module. This invention accurately simulates the vibrational displacement distribution of magnetic particles within biological tissue under the action of an alternating magnetic field, revealing the coupling law between magnetic fields and solid mechanics.

The invention provides a polynomial modeling method and device based on static magnetic field rotation-free and dispersion-free characteristics, and belongs to the technical field of indoor localization, and the method comprises the steps: employing an array type magnetic sensor to collect the data of a triaxial magnetometer in a space range, and obtaining the spatial distribution information of the magnetic field intensity; analyzing the acquired magnetic field data, determining the change rule of the magnetic field intensity along with the spatial position, and performing modeling preparation on the magnetic field based on the non-spin and non-dispersion characteristic of a Maxwell equation set; establishing a magnetic field polynomial model without spinning and scattering constraints, fitting local change of the magnetic field intensity through polynomial, and embedding a differential constraint condition without spinning and scattering into the magnetic field polynomial model to ensure that the magnetic field polynomial model meets a physical law; and calculating parameters of the polynomial model of the magnetic field by using the collected magnetic field data to obtain the polynomial model of the indoor magnetic field. The invention provides a lightweight solution for real-time magnetic field positioning and navigation in a large-scale complex environment.

The present application relates to the technical field of soft magnetic material, and provides a high-frequency magnetic hysteresis characteristic prediction method and system of soft magnetic material and electronic equipment, comprising: obtaining physical parameters of the soft magnetic material and magnetic field parameters of a magnetic field where the soft magnetic material is located; inputting the physical parameters and the magnetic field parameters into a dynamic magnetic hysteresis model to obtain a predicted value of the magnetic field intensity corresponding to static magnetic hysteresis loss, a predicted value of the magnetic field intensity corresponding to eddy current loss under high-frequency excitation and a predicted value of the magnetic field intensity corresponding to abnormal loss; the dynamic magnetic hysteresis model predicts the magnetic field intensity corresponding to the static magnetic hysteresis loss based on the Preisach model, predicts the magnetic field intensity corresponding to the eddy current loss under the high-frequency excitation based on the constructed Maxwell equation set, and predicts the magnetic field intensity corresponding to the abnormal loss based on the magnetic domain theory. The present application is used to solve the defect that the magnetic hysteresis and loss characteristics of the material under the high-frequency condition cannot be accurately simulated simultaneously due to the fact that the formula of the magnetic field intensity corresponding to the eddy current loss considering the skin effect is not derived in the prior art.

The invention relates to the technical field of ocean geophysical exploration, and provides an island tail flow induced electromagnetic field simulation method based on magnetohydrodynamics. The method comprises the following steps: constructing a three-dimensional island wake flow fluid dynamic model; coupling an equation for describing seawater motion with a Maxwell equation set for describing electromagnetic field evolution, and constructing a magnetohydrodynamic control equation set; modeling the turbulence effect of seawater movement; the magnetohydrodynamics control equation set is solved, the ocean current velocity field and the induced electromagnetic field intensity are obtained, and the induced electromagnetic field intensity comprises the induced electric field intensity and the induced magnetic field intensity. The three-dimensional island wake flow hydrodynamic model constructed by the method comprehensively considers the seawater vertical layering flow velocity profile and background geomagnetic field parameters, and the constructed magnetohydrodynamic control equation set fully considers the seawater motion, so that the model can truly reflect a terrain-flow field-electromagnetic field multi-scale coupling mechanism.

The invention relates to a calculation method for reducing armoring loss of a three-core submarine cable. Aiming at the problem of loss overestimation caused by neglecting three-phase conductor magnetic field offset and spiral magnetic field influence in a traditional calculation method, the method is based on a double-coordinate system electromagnetic model, analyzes magnetic field distribution inside and outside a conductor through a Maxwell equation set, and deduces and corrects formulas of a metal sheath loss factor lambda1 and an armoring loss factor lambda2. The inhibition effect of eddy current coupling of the armoring layer and the shielding layer, magnetic field distribution of the spiral twisting structure and the same-direction twisting technology on loss is comprehensively considered; meanwhile, the mechanism that the armored steel wire and the conductor are twisted in the same direction to reduce hysteresis and eddy-current loss is disclosed. The method can effectively improve the design precision of the submarine cable current-carrying capacity by optimizing the calculation model and the process parameters, reduces the material consumption, and is suitable for the scenes with high requirements on the economical efficiency and reliability of the cable, such as offshore wind power.

The invention discloses an electromagnetic simulation method of a microstrip line and electronic equipment. According to the microstrip line electromagnetic simulation method provided by the invention, the frequency domain polarization model is constructed by decomposing a complex dispersive medium model into superposition of a plurality of Debye relaxation terms, and the frequency domain response of each unit is converted into an independent time domain update relationship by using an auxiliary differential equation method; therefore, the high calculation overhead caused by the traditional time domain convolution operation is thoroughly avoided; furthermore, the updating relations and Maxwell equations are coupled to construct a joint solving model, discretization is carried out through a time domain finite difference method, an explicit field quantity updating operator is generated, and the electric field, the magnetic field and the polarization current component can be efficiently and synchronously updated in time domain iterative calculation. According to the method, high-precision modeling of the broadband dispersion characteristic of the PCB microstrip line is ensured, and meanwhile, the simulation calculation efficiency is remarkably improved.

The invention discloses a power transmission cable sheath insulation on-line state monitoring method, mainly relates to the technical field of on-line state monitoring, and aims to solve the problems that single-parameter monitoring is difficult to reflect a multi-field coupling mechanism of insulation degradation, infrared temperature measurement is influenced by environmental radiation and surface emissivity, off-line detection needs power-off operation, and the detection efficiency is low in the prior art. And response lag is solved. Comprising the following steps: taking a graph structure state flow as input, driving a physical simulation engine based on electromagnetic-thermal-current three-field coupling, and simulating a transient charge migration path of a partial discharge pulse in an XLPE sheath; generating a transient electromagnetic fingerprint corresponding to each node by solving and correcting a Maxwell equation set; and inputting the insulation degradation electromagnetic fingerprints into a multi-agent game model based on information entropy flow, regarding each cable node as an agent with state evaluation capability, and outputting a dynamic decision signal of an insulation health state.

The present invention provides an electrical property tomography method, system, device and medium based on instantaneous linearization, wherein the method includes: measuring a magnetic resonance radio frequency field, and calculating a transmission field based on the radio frequency field; calculating point data information of the transmission field using a numerical method; based on the transmission field and the point data information of the transmission field, according to the Maxwell equations, obtaining an initial value of the permittivity and an initial value of the conductivity at each point in space, and determining constraints K, R1 and R2 based on the initial value of the permittivity and the initial value of the conductivity; based on the transmission field, the point data information of the transmission field and the constraints K, R1 and R2, obtaining an iterative equation based on the Maxwell equations combined with the Newton iteration method; determining initial values ​​of the iterative equation based on the initial values ​​of the permittivity and the initial values ​​of the conductivity, substituting the initial values ​​into the iterative equation for iterative calculation, and obtaining the permittivity and conductivity at each point in space after several iterations; and outputting an electrical property tomography image based on the permittivity and conductivity at each point in space.

The application discloses a calculation method and system for the transmission and scattering process of low-frequency electromagnetic waves in the brain, and relates to the technical field of brain detection. The method simplifies the brain tissue into a homogeneous isotropic spherical model, which significantly reduces the calculation complexity and lays a foundation for efficient solution. Then, an electromagnetic wave propagation and scattering physical model based on Maxwell's equations is constructed to accurately describe the motion law of electromagnetic waves in brain tissue. The physical model is deeply integrated into a deep learning algorithm to efficiently solve the three-dimensional electromagnetic field distribution in the brain. Finally, the propagation path, energy distribution and scattering field characteristics of electromagnetic waves are analyzed to realize the positioning and qualitative diagnosis of brain edema, tumors and other lesions, and provide key support for brain tissue health assessment. The application overcomes the efficiency bottleneck of traditional numerical methods in brain electromagnetic calculation, improves the timeliness and accuracy of brain disease diagnosis, and provides reliable technical support for bedside rapid diagnosis of acute conditions such as stroke.

The invention provides an earth main magnetic field model modeling method, a computer device and a computer readable storage medium, and the method comprises the steps: obtaining magnetic measurement data, and generating a magnetic measurement data file; inputting the associated parameters of the multiple pieces of magnetic measurement data into a preset geomagnetic model, and calculating first corrected magnetic measurement data; establishing ocean current models in different time periods; establishing a Maxwell equation set of the ocean current induced magnetic field, and solving the Maxwell equation set according to the ocean current model of each time period to obtain an ocean current induced magnetic field model of each time period; inputting the associated parameters of the multiple pieces of magnetic measurement data into the ocean current induced magnetic field model corresponding to the same time as the magnetic measurement data to obtain an ocean current induced magnetic field predicted value of each time period, and subtracting the ocean current induced magnetic field predicted values from the multiple pieces of first correction magnetic measurement data to obtain final correction magnetic measurement data; and calculating a target earth main magnetic field model by using the final corrected magnetic survey data. The method can improve the calculation precision of the target earth main magnetic field model.

The application provides a full current wave impedance apparent resistivity detection method and system, and belongs to the technical field of survey geophysics. The method realizes apparent resistivity detection of a target area by using a radio frequency magnetotelluric method (RMT). The method mainly comprises the following steps: collecting detection data, using a sensor with a frequency range covering 1 MHz to obtain orthogonal electric field components and magnetic field components at measuring points in a detection area; obtaining dielectric constants and magnetic permeabilities of a shallow surface layer; and using the detection data to calculate full current wave impedance apparent resistivities at the measuring points by using a full current wave impedance apparent resistivity model which is not limited by quasi-static conditions. In the application, the full current wave impedance apparent resistivity model considering displacement current is derived from Maxwell equations, so that the model is not limited by quasi-static conditions and will not cause distortion of apparent resistivity at high frequencies due to non-compliance with quasi-static assumptions. The model can measure both artificial source excited electromagnetic fields and natural electromagnetic fields.

The invention discloses a transition radiation polarized wave regulation and control method and system based on an isotropic material. The regulation and control method comprises the following steps: calculating an equivalent current according to an oblique incidence electronic pulse velocity vector and converting the current into a frequency and wave number space; calculating an electron radiation field equation and an interface radiation field equation according to the Maxwell equation set; solving the electron radiation field equation and the interface radiation field equation to obtain an electron radiation field and an interface radiation field; adopting a phase matching algorithm to calculate a total field on two sides of the regulation and control material interface; calculating a transverse magnetic wave far-field radiation angular spectrum and a transverse electric wave far-field radiation angular spectrum excited during electron incidence by adopting boundary phase matching; and regulating and controlling the separation of the transition radiation polarized waves in space according to the relationship between the calculated energy angular spectrum spatial distribution of the transition radiation field and the incident angle of the electronic pulse and / or the electromagnetic parameters of the regulation and control material. According to the invention, the problem that excitation of different modes of transition radiation waves and separation of different modes of radiation fields in space are difficult to autonomously regulate and control in the prior art is solved.

The invention discloses a calculation method and system for conduction and scattering processes of low-frequency electromagnetic waves in the brain, and relates to the technical field of brain detection.The method has the advantages that brain tissues are simplified into homogeneous isotropic sphere models, accordingly, the calculation complexity can be obviously reduced, and foundations can be laid for efficient solution; an electromagnetic wave propagation and scattering physical model based on Maxwell equations is constructed, and the movement law of electromagnetic waves in brain tissue is accurately described; the physical model is deeply integrated into a deep learning algorithm, and three-dimensional intracerebral electromagnetic field distribution is efficiently solved; finally, the propagation path, energy distribution and scattered field characteristics of electromagnetic waves are analyzed, positioning and qualitative diagnosis of lesions such as encephaledema and tumors are achieved, key support is provided for brain tissue health assessment, the efficiency bottleneck of a traditional numerical method in brain electromagnetic calculation is overcome, the timeliness and accuracy of brain disease diagnosis are improved, and the method is suitable for popularization and application. And reliable technical support is provided for rapid bedside diagnosis of stroke and other emergencies.

The application relates to the technical field of metallurgical continuous casting, and discloses a numerical calculation method for defining a continuous casting electromagnetic stirring area. Firstly, based on the parameters of a continuous casting machine and the cross-sectional size of a casting blank, a three-dimensional transient solidification simulation system coupling flow, heat transfer, mass transfer and a solidification model is constructed; then Maxwell equations are embedded into the system in the form of a source term through a user-defined function, bidirectional coupling calculation of an alternating magnetic field and multiple physical fields is realized, and multiple physical field distribution results are synchronously obtained; subsequently, a solidification rate dynamic calculation model is established based on a temperature field, a target stirring area is determined; finally, combined with real-time process parameters, optimal position coordinates of electromagnetic stirring are dynamically calculated through a spatial vector algorithm, the stirring shaft angle and the action range are synchronously corrected based on the solidification front morphology, and the position, direction and action range of electromagnetic stirring are cooperatively optimized and controlled. The application solves the problem that the fixed electromagnetic stirring does not match the dynamic solidification process, and can effectively improve the core quality of the casting blank.

The application discloses a micro-nano structure extinction characteristic efficient simulation method and system based on a time domain discontinuous Galerkin technology, which is based on a Maxwell equation set, combines the time domain discontinuous Galerkin technology to construct an electromagnetic field discrete model of the micro-nano structure, adopts a reasonable tetrahedron / hexahedron mixed grid to disperse a calculation region, and introduces a numerical flux processing unit to process discontinuity of field quantities between units, so that multi-scale efficient time domain solving of the micro-nano structure is realized. When the method processes the multi-scale problem of the micro-nano structure, the number of split grids can be well reduced, the calculation time complexity is O(N), the extinction characteristic in a wide frequency spectrum range can be efficiently calculated, and the method is suitable for complex micro-nano light field problem analysis.

The invention belongs to the technical field of magnetofluid dynamics, and particularly relates to a magnetofluid flow heat transfer characteristic research method which comprises the following steps: S1, constructing a multi-physics field coupling mathematical model; a Maxwell equation set and an Ohm law are combined, a magnetic diffusion term is introduced, and an electromagnetic coupling equation is established; establishing a magnetofluid flow heat transfer equation; obtaining a corrected magnetofluid flow heat transfer equation; s2, experimental measurement and data processing: establishing a measurement system; solving the corrected magnetofluid flow heat transfer equation; and S3, efficiency calculation. The collision model and the internal energy equation are introduced, so that the problem that the temperature field distribution of the magnetofluid cannot be accurately described by the conventional model is solved. According to the method, the flow heat transfer characteristics of the magnetic fluid under the high Reynolds number can be predicted, accurate temperature distribution and speed distribution of the magnetic fluid are given, and the output power of the magnetic fluid can be effectively calculated. And optimization design of the structural layout of the magnetofluid propeller is facilitated.

The application belongs to the technical field of wave propagation, and particularly discloses a numerical simulation method for propagation characteristics before and after high-power microwave atmospheric breakdown, which is based on a rotational body time-domain finite difference method to solve an electron fluid model improved based on an empirical formula, the electron fluid model including a Maxwell equation set, an electron density continuity equation, an electron fluid momentum conservation equation and an electron fluid energy equation, and the evolution processes of electromagnetic fields, electron densities and electron energies before and after high-power microwave atmospheric breakdown can be calculated by solving the improved electron fluid model. According to different atmospheric pressures and initial electron densities, the application adopts more accurate transport coefficients, so that the simulation precision can be greatly improved; and the application can also convert a three-dimensional electromagnetic propagation problem into a quasi-two-dimensional problem, so that the simulation time can be greatly shortened and the computer memory can be saved.

A multi-winding high-frequency transformer leakage inductance analytical calculation method, comprising: determining the number of leakage inductances of the secondary winding corresponding to different primary windings according to the number of primary and secondary windings of the multi-winding high-frequency transformer; dividing the leakage magnetic energy region corresponding to different leakage inductances into winding interlayer insulation region, winding insulation region, through-flow winding region and open-circuit winding region; deriving the magnetic field intensity of the winding interlayer insulation region and the winding insulation region; deriving the magnetic field intensity of the through-flow winding region and the open-circuit winding region based on Maxwell's equations; further integrating the corresponding leakage magnetic energy according to the magnetic field intensity of each region; calculating the leakage magnetic energy corresponding to each leakage inductance according to the different leakage magnetic energy calculation region of each leakage inductance, summing the leakage magnetic energy of the corresponding region, and then calculating the leakage inductance parameters according to the magnetic field energy method. The method considers the open-circuit winding unique in the leakage inductance calculation process of the multi-winding high-frequency transformer, and accurately calculates the leakage magnetic energy of the open-circuit winding.

The present application belongs to the technical field of human electromagnetic exposure safety evaluation, and in particular to a method for mapping the magnetic leakage field of a wireless power transmission system to the induced electric field in the human body. The method comprises the following steps: S1: numerical modeling of the wireless power transmission system and the human body; S2: construction of a physical information network mapping framework; and S3: optimization of the Kolmogorov-Arnold network function strategy. The present application uses finite element numerical simulation to build a fine numerical model of the wireless power transmission system and the human body; a physical information network mapping framework is established in combination with Maxwell's equations, and the electromagnetic field physical law is used to constrain the mapping prediction accuracy of the induced electric field in the human body while only a small amount of training samples are required; the Kolmogorov-Arnold network spline basis function is used to replace the original kernel function of the physical information network layer, which improves the nonlinear solution performance of the network model. The proposed method can quickly and accurately predict the induced electric field in different organs of the human body.

The invention discloses a ground penetrating radar (GPR) inversion method based on time-frequency joint physical constraint, and relates to the technical field of ground penetrating radar detection. The method comprises the following steps: firstly, acquiring GPR common offset B-scan echo data, and constructing a data set through anti-noise processing and forward simulation; decomposing data through two-dimensional discrete wavelet transform, and outputting a fusion feature map through a time-frequency joint feature fusion module; introducing a Maxwell equation set, an electromagnetic wave propagation equation and an electromagnetic field boundary equation to construct multiple constraints; and finally, outputting a relative dielectric constant distribution diagram, and carrying out visualization and precision verification on the relative dielectric constant distribution diagram for detection. According to the method, the noise immunity and the small target recognition precision are improved through time-frequency deep fusion, the result reasonability is guaranteed through physical constraints, the efficiency is optimized based on the DLFUNet network, the method is suitable for underground pipe network distinguishing, roadbed disease diagnosis and other scenes, and the problems that a traditional method is insufficient in precision and poor in physical interpretability under the low signal-to-noise ratio are solved.

The application discloses a grounding net induced apparent magnetic impedance forward method and device based on a finite difference method, and the method realizes three-dimensional forward simulation of induced apparent magnetic impedance based on the finite difference method, starts from a differential equation satisfied by a scalar potential, deduces a partial differential equation of the scalar potential, then solves the partial differential equation by using a solving method of the finite difference method, and sequentially solves differential equations of current density and induced apparent magnetic impedance according to a Maxwell equation set, so that three-dimensional forward simulation of the induced apparent magnetic impedance is realized, researchers can more conveniently, intuitively and quickly understand the spatial distribution and change rule of the induced apparent magnetic impedance, and the method has great significance for detecting and identifying corrosion and breakpoints of the grounding net.

The application discloses a kind of three-dimensional electromagnetic potential forward modeling self-adapting finite element method, comprising the following steps: S1, using Coulomb specification to convert Maxwell equation group into the control equation of scalar potential and vector potential;S2, the gradient term of the control equation in introducing Lagrange multiplier, the solving region is discretized, and linear equation set of finite element is constructed;S3, the linear equation set of finite element is solved;S4, using the error generated by current density discontinuity as posteriori error estimator, dual weighted posteriori error estimator is added, and target grid needing refinement is determined;S5, using eight sub-refinement strategy to encrypt the target grid;S6, using the grid after encryption carries out finite element forward modeling calculation.The application can enhance the stability in the solving process of finite element system equation, and also can improve the calculation efficiency by reducing the calculation amount of additional system equation caused by grid self-adapting.

The application discloses an electromagnetic characteristic analysis method and device of a target object, an electronic device and a computer readable storage medium. The method comprises the following steps: performing simulation modeling according to boundary condition information of the target object to obtain a simulation model of the target object; performing grid division on the simulation model by using a preset structure, and establishing a time-varying electromagnetic field of a Maxwell equation group based on the simulation model after the grid division; implicitly solving the time-varying electromagnetic field of the Maxwell equation group based on double iteration of physical time and virtual time; and outputting an electromagnetic characteristic analysis result of the target object when the time-varying electromagnetic field of the Maxwell equation group converges. The electromagnetic characteristic analysis method provided by the application improves the electromagnetic characteristic analysis efficiency of the target object.