70 results about "Finite-difference time-domain method" patented technology

The invention relates to a light spot uniformity optimization method and system for a high-precision VCSEL device, and the method comprises the following steps: carrying out the light field collection of a light-emitting surface of the VCSEL device, obtaining the intensity distribution of original light spots, analyzing the non-uniformity of each light-emitting unit, and extracting the non-uniformity characteristics of the light spots. And carrying out deviation cause analysis based on the characteristics, and identifying device structure deviation parameters. According to the method, an etching process is optimized, a corrected oxidized aperture configuration scheme is obtained, near-field light field simulation is carried out by adopting a finite difference time domain method, and optimized light field distribution is verified and predicted. And finally, adaptive compensation design is carried out on the Bragg reflector structure based on a prediction result, light field regulation and control are realized, target light spot uniformity distribution is finally obtained, and the problem that systematic analysis and feedback control on non-uniformity causes of a light emitting unit layer in a device are lacked in the prior art is solved. And local bright spots or dark areas are caused.

The invention discloses a ground penetrating radar (GPR) section horizontal interference suppression method based on a diffusion model. The method comprises the following steps: (1) constructing a standardized profile interference data set containing an actual measurement sample and a simulation sample; wherein an actual measurement sample comes from an urban road detection profile, and proper samples are screened out through mean value reduction preprocessing operation; a simulation sample is subjected to forward modeling based on a time domain finite difference method (FDTD), and various road structures and underground anomaly features are simulated; (2) a comprehensive ResBlock is introduced into the diffusion model, a lightweight Agent Agent module is introduced between ResBlocks of all layers, a space attention mechanism is deployed at the middle connection position of the Unet architecture, and a strategy based on Cosine theta schema is introduced in the forward diffusion stage; (3) training by using an improved diffusion model based on the constructed data set to obtain a trained model; and (4) sending test set data into the trained model, and completing the horizontal interference suppression test reasoning of the GPR profile. According to the method, construction of the horizontal interference data set and improvement of the diffusion model are combined together, the problems that a current traditional low-rank decomposition method is insufficient in intelligent degree, difficult to consider multi-source data and depends on manual parameter adjustment are solved, and technical support is provided for GPR high-resolution imaging and anomaly detection.

The invention provides an electromagnetic thermal multi-physical field simulation method based on an FDTD / FVTD algorithm, and belongs to the technical field of electromagnetic simulation. Performing time domain finite difference discretization on the established spatial discrete model by adopting a Yee cellular structure, and calculating electromagnetic field distribution according to a Maxwell rotation equation; constructing an adaptive steady-state judgment criterion based on the instantaneous total energy change rate, and updating electromagnetic field distribution of the spatial discrete model by adopting an FDTD explicit method; calculating the electromagnetic loss power density of the spatial discrete model, and transmitting the electromagnetic loss power density into a thermal field for calculation; based on an FVTD method, thermal field distribution of the discrete model is calculated through an explicit or implicit format, and thermal field distribution information is obtained. The FDTD method is based on explicit time domain iteration, transient behaviors such as electromagnetic wave propagation and scattering can be visually captured, and the FDTD method has broadband response capability and complex medium adaptability and is especially suitable for the high-frequency electromagnetic problem. The FVTD method strictly ensures energy conservation, directly treats boundary heat flux and is suitable for non-uniform materials and complex heat transfer boundary conditions.

The invention belongs to the technical field of computational electromagnetics, and discloses a numerical calculation method for simulating electromagnetic wave propagation characteristics in time-varying plasma, which is a three-dimensional Newton-HIE-FDTD method for efficiently simulating propagation of electromagnetic waves in time-varying plasma based on a hybrid explicit-implicit finite difference time domain method and Newton's second law of motion. The method inherits the advantages of the Newton-ADE-FDTD method, the time-varying electron density is accurately represented through the time derivative, and the abundant dynamic characteristics of the time-varying plasma can be accurately captured. On the basis, the method also fuses the advantages of an HIE-FDTD method, so that the time step length of the algorithm is only restricted by the sizes of grids in two directions, and compared with other simulation methods based on time-varying plasma, the method provided by the invention is more excellent in calculation efficiency and is more suitable for large-scale popularization and application. The method is especially suitable for analysis and simulation of electromagnetic wave propagation characteristics in time-varying plasma.

The invention discloses a three-dimensional (SBC-HIE-FDTD) method for efficiently calculating the propagation characteristics of electromagnetic waves in a graphene dispersive medium on the basis of a mixed explicit-implicit finite difference time domain (HIE-FDTD) method and a surface boundary condition (SBC) of the graphene, and the three-dimensional SBC-HIE-FDTD method is used for efficiently calculating the propagation characteristics of the electromagnetic waves in the graphene dispersive medium. According to the three-dimensional SBC-HIE-FDTD method for efficiently calculating the electromagnetic field in the graphene dispersive medium, the advantages of the HIE-FDTD method in thin dielectric layer modeling and the advantages of the SBC method in the aspect of zero-thickness graphene sheet modeling are fused, so that the size of a small grid caused by a graphene sheet or a thin dielectric layer does not limit the time step length any more; compared with other simulation methods based on a graphene structure, the method has the advantages that the calculation efficiency is better, and the method is particularly suitable for analysis and simulation of radio wave propagation characteristics in a terahertz graphene absorber structure.

The invention discloses a non-uniform hexahedral mesh generation method based on a region density distribution rule, and relates to the technical field of software development technologies, and the method comprises the following steps: S1, for a solving target, carrying out mesh generation by adopting triangular surface elements, and dividing regions according to different region densities to obtain the maximum and minimum mesh sizes corresponding to each region; s2, after the step S1 is executed, grid lines are sequentially generated in the Cartesian coordinate system according to the x dimension, the y dimension and the z dimension, optimization is started from the area with the minimum maximum grid size, and the maximum grid size is obtained; the method has the advantages that the conversion from a triangular surface element grid to a non-uniform hexahedral grid is realized through modules for identifying and calculating the density distribution of a triangular surface element region, generating three-dimensional grid lines of a Cartesian coordinate system, reconstructing a ray intersecting hexahedral grid, outputting the grid and the like; the problems of mesh generation and geometric target modeling of a finite difference time domain (FDTD) method are solved.

The invention relates to a lightning trip risk assessment method and system for a current collection line of a wind power plant station, and belongs to the technical field of lightning protection of a power system, and the method comprises the following steps: collecting a multi-dimensional data set of a target wind power plant station, the multi-dimensional data set comprising lightning activity parameters, landform data, equipment structure parameters and historical lightning fault data; constructing a three-dimensional electromagnetic transient model of the current collection line, wherein the three-dimensional electromagnetic transient model of the current collection line integrates an electromagnetic transient program EMTP counterattack simulation model, a time domain finite difference method FDTD induction lightning shielding model and a terrain correction electrical geometric model EGM; calculating lightning trip-out rates based on the multi-dimensional data set and the three-dimensional electromagnetic transient model of the current collection line, wherein the lightning trip-out rates comprise an impact trip-out rate, a shielding failure trip-out rate and an induction lightning trip-out rate under fan shielding; and carrying out risk grading on the tower according to the lightning trip-out rate, establishing a terrain-tower type coupling risk assessment system, and outputting a risk assessment result.

The invention provides a novel finite difference time domain (FDTD) method based on a Newton second law of motion and a bilinear transformation (BT) technology. The method is used for simulating propagation of electromagnetic waves in time-varying magnetized plasma. According to the method, the time-varying electron density is accurately represented through the time derivative, so that abundant dynamic characteristics of the time-varying magnetized plasma can be captured more accurately. A numerical result shows that compared with a Newton-ADE-FDTD method, a traditional ADE-FDTD method and a BT-FDTD method, the Newton-BT-FDTD method provided by the invention has higher precision and calculation efficiency on the time-varying magnetized plasma, especially under the condition of the time-varying magnetized plasma with dramatic electron density change. In addition, the propagation characteristics of the electromagnetic waves in the time-varying magnetized plasma are analyzed.

The invention discloses a multi-medium sound field control system based on an AI algorithm, which belongs to the field of intelligence and comprises a data acquisition module, a sound field modeling module, an AI optimization control module, a self-adaptive adjustment module, a hardware execution module and the like. The data acquisition module is used for sampling and acquiring acoustic signals in air, water and a solid medium; the sound field modeling module is combined with a finite difference time domain method and a graph neural network to accurately simulate sound wave propagation; the AI optimization control module fuses near-end strategy optimization and a differential evolution algorithm to generate an optimal excitation parameter; the adaptive adjustment module is based on a model migration and contrast learning mechanism; the hardware execution module generates a controllable sound field by using a piezoelectric transducer array; and the feedback evaluation module passes back measurement data through laser vibration measurement and a microphone array to realize closed-loop correction of control parameters. The method has the advantages that high-precision sound wave modeling, intelligent control parameter optimization and dynamic self-adaptive adjustment capacity are achieved, and the real-time performance, stability and the like of sound field control in the multi-medium environment are improved.

The invention discloses a ground penetrating radar pipeline intelligent inversion method based on multi-scale deep learning, and belongs to the technical field of ground penetrating radar pipeline data inversion. The method aims at solving the problems that a traditional inversion method is low in resolution, high in calculation complexity, depends on prior information and the like. The method comprises the specific steps that underground simulation model data sets are constructed in batches; forward modeling calculation is carried out based on time domain finite difference, and a matching data pair of the radar B-scan image and dielectric constant distribution is generated; constructing a multi-scale deep neural network comprising a residual attention module, a dual-path space attention module, a multi-scale feature fusion module and a reconstruction module; through end-to-end training and model test optimization, an optimal model is finally stored to realize inversion output from original radar data to dielectric constant distribution. According to the method, through a multi-scale feature extraction and fusion mechanism, the recognition precision of pipelines of different sizes is effectively improved, the inversion efficiency is greatly improved, and an efficient and accurate technical scheme is provided for underground pipeline detection.

The invention discloses an arbitrary structure fast electromagnetic scattering analysis method based on time domain finite difference, and the method comprises the steps: obtaining the triangular patch data of a scatterer model, generating an extended bounding box, and improving the adaptability of a complex structure; an initial grid point set is generated by adopting an interpolation method based on a preset grid side length, and grid data is screened and optimized, so that grid division is more accurate, and calculation redundancy is effectively reduced; the optimized grid data is mapped into a three-dimensional array, and a material type and electromagnetic parameter distribution are defined, so that efficient modeling of a complex target is realized; the electromagnetic scattering characteristics are calculated based on time domain finite difference iterative calculation in combination with the surface equivalence principle and the Poynting theorem, the calculation precision and stability are improved, meanwhile, the calculation process is optimized to reduce the storage requirement and the calculation time, and therefore efficient and accurate electromagnetic scattering analysis of any structure is achieved, the calculation efficiency is improved, and the engineering application requirement is met.

The invention discloses an aflatoxin B1 detection method based on a BIC terahertz metamaterial sensor, and designs a continuous domain bound state (BIC) terahertz metamaterial sensor based on an electromagnetic theory and a time domain finite difference method. Terahertz enhanced spectrums of aflatoxin B1 solutions with different concentrations are collected, and analysis finds that the amplitude of a transmission peak of aflatoxin B1 at about 1.5 THz is gradually reduced along with the increase of the concentration of the aflatoxin B1 solution, and the frequency of the transmission peak gradually moves to a low frequency along with the increase of the concentration of the aflatoxin B1 solution; a PLS and LS-SVM quantitative model of aflatoxin is established, analysis finds that the LS-SVM model has a better effect, and the detection limit of aflatoxin B1 is 2.04 * 10 <-7 > mu g / ml. By adopting the method disclosed by the invention, rapid, nondestructive and high-sensitivity detection of the aflatoxin B1 in the grains can be realized.

The invention discloses a ground penetrating radar high-quality imaging method based on an image recovery diffusion model, and the method comprises the steps: constructing a simulation image through an open source simulation tool gprMax based on a finite difference time domain method (FDTD), and constructing a contrast high-frequency clutter-free and low-frequency clutter data set through preprocessing and fusing actual measurement clutter simulation; a double-layer routing attention mechanism is introduced on a basic model to enhance association between features, conditional information is fully utilized, discrete wavelet transform is used to effectively separate low-frequency and high-frequency information, information loss is reduced, and the high-frequency information is enhanced through an adaptive wavelet transform high-frequency enhancement module. According to the method, good improvement is achieved on a synthetic data set, acceptable effects are achieved on multiple evaluation indexes including root mean square error (MSE), peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), perceptual image similarity (LPIPS) and depth image structure and texture similarity (DISTS), and a certain underground target structure can also be recovered in actual measurement data.

The application provides a transient ground potential rise induced coupling determination method through cable shielding layer, and belongs to the technical field of cable shielding layer.The application establishes a distributed parameter partial element equivalent circuit model of a grounding network, solves transient ground potential distribution by using a finite difference time domain method, obtains equivalent transfer impedance frequency characteristics of a braided shielding layer by using a four-port S parameter vector network analysis method and a variational asymptotic homogenization multi-scale algorithm, solves core line common mode voltage and differential mode voltage by establishing a multi-conductor transmission line equation group, constructs an artificial intelligence prediction model based on a topology perception graph neural network, solves a large-scale sparse admittance matrix by using a multilevel fast multipole method to obtain full network induced voltage distribution, and establishes a quantitative relationship model between ground potential rise and core line induced voltage, so that the technical problems that cable core line induced voltage caused by transient ground potential rise is difficult to accurately predict and effectively suppress are solved.

The present invention discloses a transmission tower line simulation method, apparatus, device, and storage medium. A partial element equivalent circuit method is used to establish a partial element equivalent circuit model for a first subsystem consisting of a lightning channel, a tower, and overhead line segments directly connected to the tower. A one-dimensional time-domain finite difference method is used to establish a multi-conductor transmission line model for a second subsystem consisting of overhead line segments not directly connected to the tower. Interface node analysis equations are established between the first and second subsystems to jointly solve for the node voltages and branch currents of a high-voltage overhead transmission line system with a grounding wire. This method addresses the technical problems of large errors in tower surge assessments caused by traditional transmission tower models that fail to consider the mutual coupling between the lightning channel, tower, and transmission line, and inaccurate analysis of lightning surge impacts caused by the TEM-based MTL model's inability to accurately capture the true propagation behavior of electromagnetic waves on transmission line towers during lightning strikes.

The invention provides a plasma flow field parameter inversion method and system based on a 1D-CNN, and relates to the technical field of electromagnetic inverse scattering, and the method comprises the steps: building a plasma flow field model of a hypersonic speed target, calculating the information of a scattered field under the action of electromagnetic waves through a current density convolution-time domain finite difference method, and calculating the information of the scattered field under the action of the electromagnetic waves; solving a far field electric field component according to a near-far field extrapolation formula; sample data of multiple groups of far-zone time domain electric field components are obtained by changing inversion parameters, and a data set is constructed after the sample data are preprocessed; training a pre-built 1D-CNN model according to the data set until a preset training condition is met, and obtaining a parameter inversion model; and performing inversion according to the parameter inversion model to obtain plasma flow field parameters of the hypersonic speed target.

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.

This invention discloses a method for detecting aflatoxin B1 based on a BIC terahertz metamaterial sensor. Based on electromagnetic theory and the time-domain finite-difference method, a continuous-domain bound-state (BIC) terahertz metamaterial sensor was designed. Using this BIC terahertz metamaterial sensor, terahertz enhanced spectra of aflatoxin B1 solutions of different concentrations were acquired. Analysis revealed that the amplitude of the transmission peak of aflatoxin B1 around 1.5 THz gradually decreased with increasing aflatoxin B1 solution concentration, while the frequency of the transmission peak gradually shifted to lower frequencies with increasing aflatoxin B1 solution concentration. PLS and LS-SVM quantitative models for aflatoxin were established. Analysis showed that the LS-SVM model performed better, and the detection limit for aflatoxin B1 was found to be 2.04 × 10⁻⁶. ‑7 μg / ml. This invention enables rapid, non-destructive, and highly sensitive detection of aflatoxin B1 in grains.

The invention discloses a preparation method of a near-infrared achromatic super lens based on a nanoimprint technology, and relates to the technical field of micro-nano manufacturing. The preparation method comprises the following steps: 1, designing a target super lens by using finite element simulation software based on a time domain finite difference method, a particle swarm algorithm and a scalar diffraction algorithm; 2, preparing a silicon female die corresponding to the super lens according to the designed target super lens parameters by using electron beam lithography and deep reactive ion etching; 3, carrying out surface fluorination treatment on the silicon female die; and 4, preparing a corresponding sub-mold according to the silicon female mold, carrying out imprinting by using a nano imprinting technology and the sub-mold, and finally, etching the a-Si layer on the surface of the substrate through deep reactive ion etching by taking imprinting glue as an etching mask to obtain the super lens. According to the invention, the nanoimprint technology can be used for manufacturing the near-infrared achromatic superlens, so that the near-infrared achromatic superlens gets rid of dependence on a high-precision photoetching machine.

The invention belongs to the technical field of lunar and deep space exploration, and relates to a simulation method, device, equipment, medium and program for a lunar seismic exploration task, which are used for realizing seismic source-propagation-observation full-link closed-loop simulation, and the method comprises the following steps: establishing a two-dimensional non-uniform lunar soil wave field propagation numerical model based on a finite difference time domain method; the whole process that lunar seismic waves are generated from a seismic source and spread in different circle layer media in the moon is simulated, and a theoretical acceleration signal at a preset station position is output; establishing an MEMS lunar seismograph system model for simulating the working characteristics of the MEMS lunar seismograph in the extreme environment of the lunar surface; the theoretical acceleration signal is input into an MEMS lunar seismometer system model for simulation calculation, and a simulation output voltage signal containing noise and instrument response characteristics is obtained; and calculating the cross correlation coefficient of the signals under different lunar earthquake station layout schemes based on the simulation output voltage signal, and further quantitatively evaluating the detection efficiency of the different station layout schemes.

The invention discloses an optical mode decomposition method for a complex medium structure under a special point light source and a related device, and relates to the technical field of nano photonics and optical engineering.The method comprises the steps that a finite difference time domain method is adopted, and a three-dimensional geometric model of the complex medium structure is established; based on the three-dimensional geometric model, performing numerical simulation by adopting a finite difference time domain method, and determining electromagnetic field distribution information of the complex medium structure under the irradiation of a special point light source; performing multi-stage decomposition on the electromagnetic field distribution information to obtain a plurality of multi-pole sub-modes; respectively determining two-dimensional far-field radiation information of each multi-pole sub-mode based on the plurality of multi-pole sub-modes; and combining the two-dimensional far-field radiation information of each multi-pole sub-mode to obtain a comprehensive three-dimensional far-field radiation pattern. The optical characteristics of the complex medium structure under the irradiation of the special point light source can be effectively analyzed, and the multipole mode contribution and interaction of the complex medium structure under the irradiation of the special point light source can be accurately reflected.

The present application relates to a kind of coated optical element laser damage dominant mode determination and threshold estimation method, belong to laser optical element damage evaluation technical field.The implementation method of the present application is as follows: based on the calculation of film optical field distribution of transmission matrix method or finite difference time domain method;Temperature and stress field of film and substrate are predicted by combining finite element analysis;Compare damage threshold to determine dominant mode;And verify the accuracy of model through experiment.The present application quantifies the damage contribution of film electric field-thermal coupling model and substrate thermal analysis model by constructing them respectively, and verifies the model through small sample experiment, aims to solve the problems of complex damage competition mechanism of coated optical element film and substrate, difficult to distinguish dominant damage mode, and low efficiency and high cost of traditional experimental method.

The application discloses a complex ground surface ground penetrating radar amplitude-preserving imaging method based on an orthogonal skin mesh, and comprises the following steps: 1) constructing a ground surface model according to ground fluctuation data; constructing an electromagnetic wave underground propagation speed model according to geological exploration data; 2) generating an orthogonal skin mesh by using a Ryskin-Leal method; 3) discretizing the orthogonal skin mesh by using a finite difference time domain method; 4) performing reverse extrapolation on the received ground penetrating radar signal, and reversely propagating the electromagnetic wave field to an initial time; in the reverse extrapolation process, the spatial position of a reflection interface is calculated through a cross-correlation imaging condition, and an underground imaging profile is obtained; 5) calculating a target function gradient, and solving an inversion problem by using a conjugate gradient method to iteratively update the electromagnetic wave underground propagation speed model; and 6) generating an imaging profile of an underground structure according to the iteratively converged electromagnetic wave underground propagation speed model. The application significantly improves the precision, stability and anti-noise performance of underground imaging.

The application discloses a mine electromagnetic wave analysis method, which solves the problem that the ray tracing method cannot calculate the mine electromagnetic wave characteristics when the transmitting and receiving antennas are close to the roadway sides at the same time, and solves the problem that the finite difference time domain method cannot calculate the characteristics of the mine electromagnetic field above GHz in a large-section long roadway. Different calculation regions are divided in the simulation roadway, a data transmission interface between the ray tracing method and the finite difference time domain method is designed according to the law of conservation of energy, and the accuracy and efficiency of the mine electromagnetic wave propagation characteristics when the transmitting and receiving antennas are close to the roadway sides at the same time are improved. Guidance is provided for mine wireless communication base station planning and layout and installation position of the transmitting and receiving antennas, and the wireless transmission distance of the wireless communication system is improved under the premise that the transmitting power and the receiving sensitivity are unchanged.

The application discloses a near-bit formation detection method based on while-drilling acoustic forward-looking, and belongs to the technical field of formation detection, and comprises the following steps: S1, acquiring a while-drilling acoustic signal generated by rock breaking of a drill bit in a drilling process, performing time-frequency analysis on the while-drilling acoustic signal, and determining a while-drilling acoustic source feature in combination with theoretical analysis; S2, performing independent component analysis on the while-drilling acoustic signal, and combining with ensemble empirical mode decomposition (CEEMD) and wavelet transform to identify effective while-drilling acoustic signals from complex background noise; and S3, establishing a geophysical model of a bad geological body containing a lithology boundary surface, a fault fracture zone, a karst cave and a water-rich formation, and obtaining a propagation rule and characteristic parameters of the while-drilling acoustic signal in the model by using a time-domain finite difference numerical simulation method. Through multi-algorithm collaborative processing, the while-drilling acoustic signal with high signal-to-noise ratio and obvious characteristics is extracted from the complex background noise, and the reliability and accuracy of signal processing are improved.

The invention discloses a three-phase circuit lightning stroke identification method and device, relates to the technical field of power system positioning, and aims to accurately judge the lightning stroke type and the lightning stroke position, conveniently identify the line accident reason and quickly position the line fault caused by the lightning stroke. The method comprises the following steps: fitting a relationship between a lightning peak value on a line and a transmission distance according to a finite difference time domain method; a transient magnetic field generated by lightning stroke is induced through a PCB differential ring, and induced electromotive forces generated at the two ends of the transient magnetic field are sampled; when the induced electromotive force is greater than a set threshold value, recording current waveform data of a three-phase line; and judging an output lightning stroke type according to the current waveform data and whether the polarities of the three-phase current head waves are the same or not, and judging a lightning stroke position in combination with a relationship between a lightning peak value and a transmission distance. The lightning stroke type and the lightning stroke position can be accurately judged, and line accident reasons can be conveniently identified and line faults caused by lightning stroke can be rapidly positioned.

The invention belongs to the technical field of electronic materials, and particularly relates to an ultrahigh-temperature-resistant high-entropy ceramic carbide composite wave-absorbing material and a preparation method thereof. The composite wave-absorbing material has a three-layer structure, namely a boron nitride high-entropy ceramic layer, a low-carbon-content high-entropy ceramic carbide layer and a high-carbon-content high-entropy ceramic carbide layer. And screening the thickness and the wave-absorbing efficiency of the composite wave-absorbing material by combining an impedance matching principle and a time domain finite difference method. And putting the screened composite wave-absorbing material with the three-layer structure into a high-temperature furnace, heating to be more than or equal to 1600 DEG C in an air atmosphere, and cooling to obtain the ultrahigh-temperature-resistant high-entropy ceramic carbide composite wave-absorbing material. The average wave-absorbing efficiency of the material in the frequency band of 2-18 GHz is smaller than or equal to-8 dB, and material support is provided for electromagnetic protection requirements in the aerospace extreme high-temperature aerobic environment.

The invention discloses a field line coupling time domain modeling method, device and equipment for a bent shielded cable and a medium, and relates to the field of electromagnetic compatibility and electromagnetic field numerical calculation, and the method comprises the steps: decomposing the bent shielded cable into an inner transmission line system and an outer transmission line system according to a cable shielding layer; the shielding cable structure is removed, and FDTD is used for simulating electromagnetic field distribution generated in the area where the shielding cable is located; dividing the shielding cable according to FDTD grids, and establishing an outer transmission line equation; performing differential discretization on the outer transmission line equation by adopting an FDTD method to obtain transient voltage and current response of each point along an outer layer; extracting current along a shielding outer layer, and establishing an inner transmission line equation; and performing differential discretization on the internal transmission line equation by adopting an FDTD method to obtain transient voltage and current responses of each point along the core wire and the terminating load. According to the method, a time domain finite difference method, a transmission line equation theory and an interpolation technology are combined, and synchronous calculation of space electromagnetic field radiation and transient response of a shielding cable bending shielding outer layer and a core wire is achieved.

The application belongs to the technical field of computational electromagnetics, and discloses a numerical calculation method for simulating electromagnetic wave propagation characteristics in time-varying plasma, which is a three-dimensional Newton-HIE-FDTD method for efficiently simulating electromagnetic wave propagation in time-varying plasma based on a mixed explicit-implicit finite-difference time-domain method and Newton's second law of motion. The method inherits the advantages of the Newton-ADE-FDTD method, accurately represents the time-varying electron density through the time derivative, and can accurately capture the rich dynamic characteristics of the time-varying plasma. On this basis, the method also integrates the advantages of the HIE-FDTD method, so that the time step of the algorithm is only restricted by the grid size in two directions. Compared with other simulation methods based on time-varying plasma, the method is more efficient in calculation, and is particularly suitable for the analysis and simulation of electromagnetic wave propagation characteristics in time-varying plasma.

The invention discloses a hybrid implicit-explicit finite-difference time domain electromagnetic simulation method based on a body-centered square grid, belongs to the technical field of electromagnetic simulation, and aims at solving the problem that an existing method cannot give consideration to calculation efficiency and numerical isotropy at the same time. A mixed implicit-explicit time marching strategy is introduced, implicit updating is carried out on one space direction, explicit updating is carried out on other directions, and field quantity iteration is completed by solving a column-by-column three-diagonal linear system. According to the method, high precision and isotropy are kept, meanwhile, time step length limitation is remarkably relaxed, and the calculation efficiency of large-scale electromagnetic simulation is improved.