14 results about "Perfectly matched layer" patented technology

The invention provides a well-ground frequency domain electromagnetic detection method and device and electronic equipment, and the method comprises the steps: setting a perfect matching layer based on stretching coordinate transformation at the outer side of a model based on a three-dimensional geologic model, constructing an overall computational domain, facing the overall computational domain, and implementing adaptive mesh generation according to posterior error estimation. And generating an unstructured tetrahedral mesh which is locally refined in a target area, and on the tetrahedral mesh, performing spatial discretization and solution on a frequency domain Maxwell equation by adopting a first-order or second-order vector finite element in an H (curl) space to realize well-ground frequency domain electromagnetic forward modeling calculation. According to the method, through cooperation of the adaptive grids and the vector finite elements under the microframework, both precision and efficiency are considered, forward modeling stability and imaging resolution are improved, and a scientific basis is provided for efficiency improvement and cost saving of mineral resource exploration and development.

The invention relates to an incident wave loading method for simulating ground electromagnetic scattering based on FDTD. The incident wave loading method comprises the steps of solving an attenuation factor at a certain depth of a PML, arranging the side face and the bottom face of a connection boundary CB on the PML, establishing a ground electromagnetic scattering model, connecting the boundary to load an incident wave, and solving an electric field value and a magnetic field value of the loaded incident wave. According to the method, the four side faces and the bottom face of the connecting boundary CB are completely arranged on the PML, incident waves penetrate through the CB to enter the PML in a non-reflection mode, the edge effect generated by truncation of the periphery of the ground is effectively reduced, and the precision of ground electromagnetic scattering calculation is improved. The truncated ground is limited in a CB boundary area, and calculation of a reflection field and a transmission field is avoided. The method does not depend on ground parameters, and electromagnetic scattering calculation of rough ground and layered ground can be achieved.

The invention relates to a high-order staggered grid viscous sound medium reverse time migration tunnel advanced detection method and system, and belongs to the field of tunnel engineering geophysical prospecting. According to the method, a viscoelastic anisotropic TTI medium anisotropy wave equation expressed by a fractional Laplace operator is deduced, and a viscoelastic anisotropic TTI medium first-order speed-stress elastic wave equation is solved by adopting a high-order staggered grid finite difference method. According to the invention, the wave field information at any moment is obtained, so that the propagation process of seismic waves in an underground medium is simulated more accurately. In order to solve the problem of reflection possibly caused by artificial boundaries, a PML (perfectly matched layer) absorption boundary processing method of a new attenuation function is adopted. According to the method, seismic waves can be effectively absorbed, reflection is avoided, and therefore simulation stability and accuracy are guaranteed. Generally speaking, the invention provides an accurate and stable tunnel advanced detection forward modeling method, and a reverse time migration algorithm is carried out in an attenuation TTI medium.

The invention discloses a broadband uniaxial anisotropic complete matching layer absorption boundary method, and belongs to the field of computational electromagnetism. The method comprises the following steps: initializing electromagnetic field component coefficients (Ex, Ey, Hz), an excitation source and W-UPML parameters; constructing a matrix equation through an AH domain differential operator to solve a magnetic field component coefficient, and converting an AH domain field value into a time domain field value in combination with a domain inverse transformation formula; and high-efficiency calculation and boundary absorption of a broadband electromagnetic field are realized by utilizing a Hermite orthogonal basis function and an attenuation factor b. Compared with a traditional method, the time step size stability limitation is avoided through AH domain transformation, and the calculation efficiency is remarkably improved; the low-frequency wave absorption performance is enhanced by the introduced attenuation factor, and the reflection error is reduced by 20dB compared with that of the traditional UPML. The method is suitable for the fields of electromagnetic simulation, seismic wave simulation and the like, and effective technical support is provided for high-precision and broadband electromagnetic field analysis.

The present invention discloses a method for calculating the absorption and scattering characteristics of nanoparticles at the quantum scale. A nanoparticle model is established in finite element software: from the outside to the inside, there are a perfectly matched layer, an external environment dielectric layer, a weak form computational domain, and a metal particle, where the position of the computational domain added to the weak form computational domain is selected to be in the middle of the external environment dielectric layer and the metal particle region; then the material parameters are set; secondly, the integration region for calculating the absorption factor is set: the weak form computational domain and the metal particle region are set as the integration region for calculating the absorption factor; finally, calculations are performed and the results are exported: a parametric sweep is added under the research module, the change ranges of the incident light wavelength and the radius of the metal nanoparticle are set and the calculations are started, a one-dimensional plot group is selected in the results to plot the absorption factor graph; a two-dimensional plot group is selected to plot the electric field distribution graph.

The application discloses a hybrid electromagnetic simulation method suitable for a multi-scale fine structure antenna, and comprises the following steps: firstly, a multi-scale fine structure antenna model to be simulated is created, and the range of the size of the model in a calculation space is determined; a convolutional perfectly matched layer suitable for a hybrid implicit-explicit finite difference time domain method is constructed, and the range of the entire calculation space containing the convolutional perfectly matched layer is determined, then a non-uniform grid is set, a fine region and a transition region from fine to coarse are determined; the three are combined, an excitation source of an electric field is added, then a convolutional perfectly matched layer absorption term, a magnetic field value and an electric field value at the next moment are obtained; finally, the excitation source of the fine structure direction is updated, and a time step is updated. The application proposes a method of efficiently combining a hybrid implicit-explicit finite difference time domain method with a non-uniform grid technology and a convolutional perfectly matched layer, which not only improves the calculation precision, but also significantly simplifies the implementation process and improves the calculation efficiency.

The invention relates to a mixed absorption boundary electromagnetic wave numerical simulation method, belongs to the technical field of computational electromagnetics, and solves the technical problem that a Mur absorption boundary condition cannot be directly used for a coordinate telescopic medium, and the simulation method comprises the following steps: establishing a mixed absorption boundary electromagnetic wave numerical calculation model; setting CPML (Convolution Complete Matching Layer) parameters; calculating electromagnetic field distribution in the model; calculating a parameter I A, a parameter II B and a parameter III C required by the mixed boundary; calculating the electric field of the boundary of the outermost layer of the CPML; calculating a magnetic field at the next moment; and a step of iteration. The Mur absorption boundary is seamlessly combined with the CPML, and an electromagnetic field in a coordinate telescoping medium is solved by using time domain finite difference FDTD. The method is used for mixed absorption boundary electromagnetic wave numerical simulation in the coordinate telescopic medium.

The invention provides an optimal frequency selection method for online monitoring bolt torque based on ultrasonic guided waves, belongs to the technical field of intelligent sensing systems, and solves the problems that the frequency of the ultrasonic guided waves in bolt connection detection is mostly determined according to experience and cannot fully excite all dynamic characteristics of the system, so that the real performance of the system cannot be comprehensively reflected by a measurement result, and the reliability of the system is influenced. The method comprises the following steps: establishing a two-dimensional frequency domain finite element model based on physical field simulation software; perfect matching layers are added to the two sides of the established two-dimensional frequency domain finite element model; placing a piezoelectric wafer as an excitation source in a transmission area of the two-dimensional frequency domain finite element model added with the perfect matching layer, and generating an ultrasonic guided wave signal; setting a contact pair and a boundary pair in a contact area of the two-dimensional frequency domain finite element model; frequency scanning analysis is carried out on the basis of the content, and the excitation center frequency corresponding to the change curve peak value of the total transmission energy TE is selected as the optimal excitation center frequency.

The application belongs to the field of electromagnetism, and particularly relates to a kind of time domain finite difference method open field simulation high-order perfectly matched layer implementation method and system, aims at solving how to avoid the problem of cascade solution and parameter coupling in PML under the same algorithm consumption as existing high-order PML. The method comprises: constructing PML tensor, the inverse of which is the weighted sum of the inverses of multiple complex frequency shift PML sub-tensors; constructing PML auxiliary variables based on PML tensor and Maxwell equations, including electric field component coupling auxiliary variables and magnetic field component coupling auxiliary variables; updating PML auxiliary variables using recursive convolution method or auxiliary differential equation method, and updating electric field intensity components and magnetic field intensity components according to the updated PML auxiliary variables. The time domain finite difference method open field simulation high-order PML implementation method and system provided in the application effectively overcome the defects of existing high-order PML cascade solution complexity and parameter coupling under the same algorithm consumption.

The invention provides a multi-group cross-correlation micro-seismic source positioning method based on dynamic quality weighting, and the method comprises the steps: constructing the dynamic quality weight of a signal based on an energy stability index, a signal-to-noise ratio index and a spatial coherence index of the signal of each receiver in a noise environment; grouping to obtain a signal of a dynamic grouping number G through a two-dimensional feature clustering method combining the three-dimensional coordinates of the receivers and the dynamic quality weights; carrying out time reversal on each group of signals, then carrying out wave field back propagation, applying a perfect matching layer to the boundary of the wave field to absorb a condition to suppress noise, obtaining wave field energy in each group, and carrying out geometric mean operation integration to obtain imaging data of each group of signals; after imaging data are integrated, space-time filtering is carried out, and an effective seismic source position is detected by combining a connected domain detection algorithm. Therefore, the method of fusing the dynamic quality weight of the signal, the dynamic grouping strategy and the perfect matching layer absorption condition geometric average imaging realizes the high-precision positioning of the micro seismic source, and solves the problems of noise sensitivity and weak seismic source leak detection.

The invention discloses a liquid filling pipeline transmission loss calculation method, system and device under the sound-solid coupling condition, a medium and a product, and relates to the technical field of pipeline noise control, and the method comprises the steps: constructing a liquid filling pipeline transmission loss calculation model of a target liquid filling pipeline under the sound-solid coupling condition, boundary conditions and excitation are applied to the liquid filling pipeline transmission loss calculation model, waveguide analysis working conditions are constructed, and vibration-sound response is calculated based on the waveguide analysis working conditions; determining vibration-sound coupling wave characteristics of the liquid-filled pipeline based on the liquid-filled pipeline transmission loss calculation model; on the basis of the vibration-sound response and the vibration-sound coupling wave characteristics, pipeline propagation wave information in the target liquid filling pipeline is obtained; and calculating the transmission loss of the target liquid-filled pipeline under the acoustic-solid coupling condition by utilizing a perfect matching layer technology based on the liquid-filled pipeline transmission loss calculation model and the pipeline propagation wave information. According to the method, the accuracy and effectiveness of calculation of the transmission loss of the liquid filling pipeline under the acoustic-solid coupling condition are improved.

This invention provides a well-to-surface frequency domain electromagnetic detection method, device, and electronic equipment. It includes constructing a holistic computational domain based on a three-dimensional geological model, setting a perfectly matched layer based on stretched coordinate transformation outside the model, and performing adaptive mesh generation based on posterior error estimation within this domain. This generates a locally refined unstructured tetrahedral mesh in the target area. On this tetrahedral mesh, first- or second-order vector finite element methods are used in H (curl) space to spatially discretize and solve Maxwell's equations in the frequency domain, achieving well-to-surface frequency domain electromagnetic forward modeling. This invention, through the synergy of adaptive meshing and vector finite element methods within a differentiable framework, balances accuracy and efficiency, improves forward modeling stability and imaging resolution, and provides a scientific basis for improving efficiency and saving costs in mineral resource exploration and development.

The present invention discloses a method for simulating the light intensity distribution of thick-resist photolithography processes. The method comprises the following steps: constructing a corresponding model in FDTD based on actual contact / proximity photolithography conditions, applying a plane wave with controllable incident angle, polarization direction, and wavelength; processing the dispersive medium using a recursive convolution method; adding a convolutional perfectly matched layer (CPML) boundary to the simulation region; performing a loop calculation to update the electric and magnetic fields at each Yee grid point within each time step until a steady state is reached; and obtaining the light intensity distribution within the photoresist using a peak detection method based on the distribution of the electromagnetic field within the grid. This method addresses the current lack of high-precision simulation models for thick-resist photolithography processes, offers high flexibility, and is suitable for simulating complex photolithography scenarios.

The application relates to a kind of based on display stable compensation viscous anisotropic reverse time migration method, system and medium, comprising: by explicit stable compensation constant fractional order viscous wave equation and perfectly matched layer absorbing boundary condition, from initial time, along time direction forward solution, obtain the seismic wave field value of all time; By explicit stable compensation constant fractional order viscous wave equation and perfectly matched layer absorbing boundary condition, along time negative direction reconstruction seismic wave field;From the maximum time, along time direction negative solution, obtain the seismic wave field value of all time at geophone point;According to seismic wave field and geophone point seismic wave field, obtain underground structure imaging result.It can stably compensate the amplitude attenuation phenomenon, does not produce high frequency abnormal value, in the case where quality factor Q changes sharply with space, amplitude compensation and migration imaging can also be accurately carried out, ensure that stratum phase axis is reasonably and correctly homing.