54 results about "Maxwell's equations" patented technology

The invention discloses a composite shielding material effect experiment data analysis method, and particularly relates to the field of material shielding effect analysis, and the method comprises the following steps: measuring key data such as dielectric constant, magnetic conductivity, conductivity and thickness of each layer of a composite shielding material through an electromagnetic performance measurement instrument; establishing an electromagnetic wave propagation model for describing propagation of electromagnetic waves in the multilayer medium based on a Maxwell equation, and defining boundary conditions of a test sample; time domain and frequency domain characteristics of an electromagnetic interference source are simulated through Fourier transform, and actual input interference is simulated. And analyzing the dynamic response of the electromagnetic wave propagation model under transient and steady-state interference signals to form an electromagnetic wave interference response propagation model. Through comparison with actual shielding effectiveness test data, model parameters are adjusted, and it is ensured that model calculation errors are within an acceptable range. A full-band shielding effectiveness prediction map of the composite shielding material is generated based on the model, and theoretical support is provided for material design and optimization.

The invention discloses a state evaluation and fault early warning method and system based on superconducting current limiter modeling, an electromagnetic heat multi-physical field coupling model of a superconducting current limiter is constructed based on finite element software, and the method comprises the following steps: constructing a three-dimensional geometric structure of a solenoid-shaped superconducting current limiter, and setting a peripheral electromagnetic environment boundary; establishing an electromagnetic field control equation based on a Maxwell equation set and the nonlinear resistivity characteristic of the superconducting material, and coupling a solid heat transfer control equation to form a multi-physical field interaction model; optimizing grid division to balance calculation precision and solving efficiency; body parameters of the superconducting current limiter including the initial critical current Ic0 and the critical temperature Tc and working condition parameters including the environment temperature and the transmission current It are input, the parameters are dynamically adjusted according to the actual operation scene, and the voltage U at the two ends during normal operation is calculated through a model; by collecting voltage measured values Up at the two ends of the superconducting current limiter during actual operation in real time, whether the voltage measured values Up exceed a threshold value set according to the voltage U or not is judged, and an early warning mechanism is triggered.

The invention discloses a multi-mode online detection method and system for transformer oil, and relates to the technical field of online monitoring of transformer oil, and the method comprises the steps: deducing a dielectric constant based on a Maxwell equation and an electric displacement invariant principle in combination with a real-time voltage; segmenting, marking and sharpening a real-time visual image by combining a curvature prior smoothing approximation algorithm with a segmentation mark sharpening method; performing denoising enhancement on the real-time thermodynamic image by adopting a filtering mapping enhancement method to generate a real-time enhanced thermodynamic image, and deducing the temperature based on region screening and colorimetric mapping; deriving an acid value based on the gray value of the second target visual image in combination with a fluorescence standard curve, obtaining the actual height of an oil column in a third target visual image through an improved edge detection and scale scaling method, and calculating the change height of the oil column to reflect the viscosity; an aging index is generated through analysis of a logic regression device, and whether to adjust a monitoring interval or send an early warning prompt is dynamically decided based on an early warning decision mechanism, so that online self-adaptive detection and early warning of the transformer oil are realized.

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 relates to a multi-physics field coupling method for a smelting process of a ferronickel heating furnace, and relates to the multi-physics field coupling method for the ferronickel heating furnace, the method comprises the following steps: establishing a ferronickel heating model, importing the ferronickel heating model into ICEM software for grid division, and finally importing a grid into FLUENT; according to the method, based on a Maxwell's equation and an Ohm's law, an electrothermal conversion algorithm, an electromagnetic induction algorithm and a multiphase heat transfer and mass transfer algorithm are compiled in combination with a user-defined function (UDF), so that a mathematical analysis model for mutual coupling of multiple physical fields, multiphase flows and furnace body thermal stress in smelting of the submerged arc furnace is established. The model is combined with a radiation model, a turbulence model, a multi-phase flow model and a static structure model, a heat and mass transfer mechanism among an electric arc, a molten pool and a furnace body is disclosed, an influence mechanism of a furnace body structure and a multi-physical field on furnace body temperature distribution is explored, and an action mechanism between the furnace body temperature and thermal stress is clarified, so that the deformation position and deformation amount of the furnace body are predicted.

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.

A method of conical anisotropic rigorous coupled wave analysis for grating and a computing device are disclosed. The method includes: obtaining a target geometric phase δ′g for the anisotropic-material-based grating; obtaining a slow axis azimuth angle ϕc(x) of the anisotropic-material-based grating according to the target geometric phase δ′g; obtaining a permittivity tensor of the anisotropic-material-based grating, wherein the anisotropic-material-based grating has an ordinary index no and an extraordinary index ne, the anisotropic-material-based grating has a slow axis polar angle θc and slow axis azimuth angle ϕc(x), and the permittivity tensor is based on no, ne, θc and ϕc(x); applying the permittivity tensor into Maxwell equations; obtaining electromagnetic field for the anisotropic-material-based grating by using boundary conditions of at least two layers or sublayers of the anisotropic-material-based grating to obtain a diffraction efficiency for the anisotropic-material-based grating.

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 method for locating and characterizing one or more electromagnetic radiation sources. The method comprises the steps of: measuring one or more electrical signals received from one or more sources placed in an observation area in front of the sampling device; time reversal of the measured one or more electrical signals; inputting the one or more time-inverted electrical signals into an electromagnetic field resolver, the electromagnetic field resolver modeling the sampling device and being configured to solve a Maxwell equation; determining a reconstructed electromagnetic field by operating an electromagnetic field resolver with the one or more time-reversed electrical signals as one or more input signals; identifying one or more focuses in the reconstructed electromagnetic field, thereby locating one or more modeling sources in the simulated observation region; and directly or indirectly obtaining respective far-field radiation patterns of the one or more modeled sources from the reconstructed electromagnetic field.

The present invention discloses an electromagnetic wave finite-difference time-domain (FDTD) method and system based on anisotropic media conditions, relating to the field of electromagnetic detection. Starting from Maxwell's equations, the method involves the constitutive relationship of the medium in tensor representation, which is given anisotropic properties. The method creatively introduces transverse wave vector parameters into the classic one-dimensional FDTD method, replacing the transverse partial derivatives in Maxwell's equations that do not belong to the propagation direction with the corresponding transverse wave vector parameters. This method can realize a one-dimensional solution for two-dimensional or three-dimensional electromagnetic problems. By setting the corresponding transverse wave vector parameters, the field intensity distribution of the electromagnetic wave can also be calculated under different conditions of normal incidence or oblique incidence.

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 invention discloses an efficient simulation method and system for extinction characteristics of a micro-nano structure based on a time domain discontinuous Galerkin technology, and the method comprises the steps: building an electromagnetic field discrete model of the micro-nano structure based on a Maxwell equation set in combination with the time domain discontinuous Galerkin technology; reasonable tetrahedron / hexahedron mixed grid discretization is adopted for a calculation area, and multi-scale high-efficiency time domain solution of the micro-nano structure is realized by introducing discontinuity of field quantities among numerical flux processing units. When the method is used for processing the multi-scale problem of the micro-nano structure, the number of subdivision 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 analyzing the problem of a complex micro-nano light field.

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 present invention provides a method for optimizing the magnetic field uniformity of a Helmholtz coil device based on a differential evolution algorithm, comprising the following steps: Step S1: Construct an improved Helmholtz coil device model; Step S2: Derive and construct a partial differential equation of the magnetic field of the improved Helmholtz coil device according to Maxwell's equations; Step S3: Use the differential evolution algorithm to optimize the improved Helmholtz coil device to determine the optimal values of the coil spacing and the radius of the newly added central coil of the improved device under different application scenarios, so as to achieve the optimal magnetic field uniformity of the improved Helmholtz coil device. Applying this technical solution can determine the optimal values of the coil spacing and the radius of the newly added central coil of the improved Helmholtz coil device, and achieve the optimal magnetic field uniformity of the improved device.

During operation, a computer system may acquire magnetic resonance (MR) signals associated with a sample from a measurement device or memory. Then, the computer system may access a predetermined set of coil magnetic field basis vectors associated with a surface surrounding the sample, where coil sensitivities of coils in the measurement device are represented by weighted superpositions of the predetermined set of coil magnetic field basis vectors using coefficients, and where the predetermined coil magnetic field basis vectors are solutions to Maxwell's equations. Next, the computer system may solve, on a voxel-by-voxel basis for voxels associated with the sample, a nonlinear optimization problem for MR information associated with the sample and the coefficients using: a forward model that uses the MR information as inputs and simulates response physics of the sample, the MR signals and the predetermined set of coil magnetic field basis vectors.

The present invention belongs to the field of electromagnetic particle simulation, and relates to a method, system, device and medium for electromagnetic particle simulation in a vacuum confluence area, including the following processes: S1: Construct a particle simulation domain for the electric field and magnetic field in the vacuum confluence area, inject particles into the particle simulation domain, and perform regional decomposition on the particle simulation domain to obtain a plurality of sub-domains; S2: Obtain the charge density and current density of grid points in each sub-domain; discretize the Maxwell equations into the form of the Cx = D equation, substitute the charge density and current density of grid points in each sub-domain into the Cx = D equation, and use the GMRES algorithm to solve the Cx = D equation to obtain the electric potential and vector magnetic potential distributions in each sub-domain; S3: Solve to obtain the electric field strength and magnetic induction intensity of grid points in each sub-domain, obtain the electric field and magnetic field received by the particles, so as to determine the particle positions at the next time step in each sub-domain; S4: Update the electric field and magnetic field received by the particles in each sub-domain at the next time step.

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.