1339 results about "Low frequency band" patented technology

The invention provides an aero-engine state monitoring method and device based on sound and vibration fusion and a computer readable storage medium, and relates to the technical field of aero-engine state monitoring. The method comprises the following steps: acquiring signals respectively acquired by a vibration sensor and a sound sensor; respectively intercepting a vibration signal low-frequency component and a sound signal high-frequency component based on the frequency response characteristic difference of the sensor; performing normalization processing on the intercepted signal to eliminate amplitude difference; constructing a transition region through an interpolation method, and splicing the continuous mixed frequency spectrum to obtain a sound-vibration fusion spectrum; and establishing a health benchmark based on the normal state fusion spectrum, and realizing abnormity monitoring and alarm through characteristic difference analysis. Advantages and characteristics of a low-frequency band of the vibration sensor and a high-frequency band of the sound sensor are fully utilized, frequency response limitation of a traditional single sensor is broken through, deep fusion of sound and vibration signals is achieved, the effective detection frequency range is remarkably widened, and accuracy and robustness of recognition of early faults such as aero-engine blade breakage are improved.

The invention discloses a cascaded discrete wavelet multiband decomposition attention image denoising method and device, and the method comprises the following steps: building a CDW-MDA image denoising network which employs an encoder-sub-network-decoder structure; inputting a noise image and extracting high and low frequency band characteristic patterns under multiple scales; global and local key feature information is enhanced; evaluating the importance of texture detail components and weighting noise features of different frequency bands; enhancing selective features of the processed high and low frequency band feature maps, and fusing the high and low frequency band feature maps; and converting the fused high-low frequency band feature map to obtain a residual image, and finally obtaining a target image. According to the image denoising method, clearer texture details can be generated, blurring is avoided, and more texture detail information is reserved in the restored image; noise can be reduced while image feature textures are kept, edge information is reserved, and a better visual effect is achieved.

A terminal includes a reception unit that receives a synchronization signal block in an unlicensed band of a high frequency band higher than or equal to a frequency band of a frequency range 2 (FR2), the FR2 being in a range including a frequency range 1 (FR1) that is a low frequency band and the FR2 that is a high frequency band in a new radio (NR) system; and a control unit that identifies, based on the received synchronization signal block, an index of a candidate position for a transmission corresponding to the received synchronization signal block, from among candidate positions for transmitting a synchronization signal block, the number of the candidate positions being greater than a predetermined number.

The invention relates to the technical field of atmosphere lamp control, and discloses an audio analysis control method of a pickup atmosphere lamp and an atmosphere lamp thereof.The audio analysis control method of the pickup atmosphere lamp comprises the steps that the atmosphere lamp collects sound through a built-in sound receiving part, and the sound collected by the sound receiving part comprises music, music, music, music, music and the like; the sound is analyzed and processed through audio analysis, the audio analysis comprises sound preprocessing, the preprocessed sound is subjected to time domain feature extraction and frequency domain feature extraction to obtain the energy ratio of each frequency band of the sound, and each frequency band comprises a high-energy frequency band and a low-energy frequency band; and performing moving average filtering on the low-frequency-band energy to generate an energy envelope line. According to the invention, collected music signals are processed in real time through audio analysis, and information such as rhythm, frequency and intensity of music is extracted. The audio analysis technology ensures that light can be highly synchronized with music, and the user experience is improved.

The invention discloses an LED lamp strip rhythm flickering control method and system, a storage medium and a program product, and the method comprises the steps: calculating a relative entropy value among a high-frequency band, a middle-frequency band and a low-frequency band; establishing an energy flow diagram, and determining a dominant frequency band according to an energy flow topological structure in the energy flow diagram; a phase tracking function is constructed, and hierarchical level division is carried out on the beat mark points; establishing a recursive segmentation window, calculating a spectrum centroid trajectory, and extracting an inflection point sequence; establishing a corresponding relation between the polar coordinate angle and the color parameter of the LED lamp strip and a corresponding relation between the polar radius and the brightness parameter; a spatial propagation mode of the LED lamp strip is designed based on the topological structure of the energy flow diagram, so that the propagation direction of the light effect along the LED lamp strip is kept consistent with the energy flow direction between the frequency bands, and the propagation speed is adjusted according to the energy flow intensity; and generating a driving control sequence of the LED lamp strip according to the gradient function. The emotional progression and tension change of music are captured, and the LED lamp strip is accurately controlled to flicker according to the emotional progression and the tension change.

The invention discloses a machine learning optimization method of a low-frequency sound absorption structure based on three-dimensional printing, and belongs to the technical field of artificial intelligence acoustics, the low-frequency sound absorption structure is prepared from a photosensitive resin material through photocuring three-dimensional printing, and comprises a side seam, an extension cavity, a circular through hole, a resonance cavity, a first partition plate, a second partition plate and a third partition plate, the method has good expansibility and can be adjusted according to different noise control requirements; through a machine learning optimization method, structure parameters can be quickly adjusted to cope with a noise control task on the premise of ensuring a small size, so that a remarkable sound absorption effect is obtained at a specific low-frequency band; according to the method, a machine learning method based on a multi-layer perceptron and a genetic algorithm is adopted, geometric parameters of the low-frequency sound absorption structure are optimized, simulation calculation is carried out by using a commercial finite element solver COMSOL Multiphysics, and the sound absorption performance of the structure is further verified and optimized.

The invention discloses a data exchange method and system for low-frequency-band wireless networking, particularly relates to the technical field of wireless networking communication, and is used for solving the problem that the data exchange efficiency of the low-frequency-band wireless networking is low. Information correction is carried out by selecting the optimal transmission path and combining feedback of the adjacent nodes, the stability and accuracy of data transmission are improved, the nodes evaluate the information state according to the information receiving quality and the environment change and select a proper correction strategy, and in the path transmission process, real-time error evaluation is used for calculating the error metric of each path, so that the accuracy of data transmission is improved. And according to the selected correction strategy, in combination with a forward error correction and automatic retransmission mechanism, error control is performed when the path quality becomes poor, and the path and the correction strategy are dynamically adjusted in low-frequency-band wireless networking, so that the fault-tolerant capability and the robustness of the network are improved, and transmission errors caused by signal attenuation or interference are effectively reduced. The reliability of data transmission is enhanced, the system adapts to a complex wireless environment, and the risk of information loss and misinformation transmission is reduced.

The invention discloses a broadband oscillation identification method and system based on a multi-band Nyquist criterion, and the method comprises the steps: dividing the frequency of broadband oscillation into a low frequency band, a middle frequency band and a high frequency band with overlapped frequency bands, and obtaining the oscillation signals of a monitoring node in a power grid in different frequency bands; respectively calculating the equivalent impedance of the non-overlapped frequency band of each frequency band and the equivalent impedance of the overlapped frequency band in the two adjacent frequency bands so as to construct the equivalent impedance of the low frequency band, the middle frequency band and the high frequency band with the overlapped frequency bands; establishing a Nyquist criterion of each frequency band based on a transfer function of dynamic characteristics of each frequency band in an open-loop state of the system; a generalized Nyquist criterion of the overlapped frequency bands is constructed by using the multi-frequency-band coupling matrix; constructing a comprehensive decision function according to the recognition result of the generalized Nyquist criterion on the system stability, the broadband oscillation comprehensive characteristic quantity and the change rate of the high-frequency-band impedance module value along with the frequency; and according to the value of the comprehensive decision function and a threshold value, a broadband oscillation identification result is determined, and the broadband oscillation identification capability is improved.

The invention discloses a liquid crystal display screen gray scale control method based on adaptive brightness compensation, which relates to the technical field of liquid crystal display screen control, and comprises the following steps: collecting environmental spectrum distribution information and a pixel gray scale voltage response curve of a liquid crystal display screen in real time, and carrying out fusion processing to form a time sequence joint feature vector; through multi-mode synchronous sampling and time sequence joint feature vector generation, ambient light and screen content changes are accurately captured, target adjustment values of backlight power and gray scale voltage are dynamically predicted, and response lag and overshoot are avoided. Through spectral domain balancing and a self-adaptive damping scheduling mechanism, cooperative control of backlight and gray scale is optimized, high-frequency oscillation is suppressed, and linear response of a low-frequency band is ensured. Meanwhile, Gamma mapping and global color gamut calibration are dynamically refreshed, accurate adjustment of area-level brightness and gray scale is achieved, and continuity of the display effect and visual experience of a user are improved.

The invention discloses a frequency division control radio frequency power supply solid-state impedance matcher and a method thereof, and aims to solve the problems that a traditional mechanical impedance matcher is slow in response, low in adjustment precision and difficult to adapt to a dynamic load. According to the system, an all-solid-state impedance matcher is adopted, impedance dynamic adjustment is achieved through a matching network composed of an adjustable inductance module and a switched capacitor module, closed-loop control is constructed in combination with a radio frequency signal detection module and a digital signal processor, and a frequency division control strategy is adopted, and the high-frequency band realizes high-precision matching through a control strategy of coarse adjustment of the adjustable inductance module and fine adjustment of the switched capacitor module. The device has the advantages of high response speed, wide frequency band coverage and the like, and is particularly suitable for industrial plasma application scenes with remarkable dynamic impedance characteristics.

The invention provides a grid-connected converter multi-band control device and method for suppressing broadband oscillation. The device comprises a cascade multi-scale controller and a broadband oscillation controller. According to the invention, cooperative damping control is carried out on different controllers of the grid-connected converter by adjusting the software control mode of the grid-connected converter. Oscillation signals of different frequency bands are collected, oscillation frequency bands are divided into a low frequency band, a middle frequency band and a high frequency band, damping controllers are arranged in the different frequency bands, broadband oscillation of the grid-connected converter is restrained, and broadband oscillation caused by interaction between the grid-connected converter and a power grid and interaction between converters under different power grid intensities and different working points can be restrained. And the stability of a grid-connected converter single-machine / multi-machine system is comprehensively improved. Moreover, the method is suitable for equipment and scenes such as a wind power grid-connected converter, a photovoltaic grid-connected converter, a flexible direct current transmission converter, a flexible alternating current system converter and the like.

The invention discloses an overlapped finite element method-based underwater target low and medium frequency sound scattering field forecasting method, which comprises the following steps of: generating a virtual node in an overlapped finite element, distributing a group of quadratic complete shift polynomial basis functions in a local analysis domain of each field node to construct local field approximation, and multiplying the local field approximation by a unit decomposition function of the overlapped finite element, constructing a high-order overlapping finite element approximation function; the method comprises the following steps: cutting off an infinite fluid domain by using an artificial boundary, and introducing a Dirichlet-to-Neumann mapping technology to realize a non-reflection boundary condition. For the problem of underwater target sound scattering in middle and low frequency bands, an overlapped finite element numerical calculation model of elastic target sound scattering is established. According to the method, high-order field variable approximation is realized by using the standard low-order finite element grid, the numerical dispersion error and the numerical anisotropy are effectively inhibited, and the low and medium frequency sound scattering field of the elastic target in the infinite water area can be accurately forecasted.

The present invention discloses a high polarization isolation dual-polarization tightly coupled ultra-wideband phased array antenna. It includes a dipole unit, a coaxial feed line, a metal reflective floor, a fishbone cross-shaped patch and a cross-shaped metal wall; the dipole unit includes a horizontal and two vertical dielectric substrates, and the vertical dielectric substrates are orthogonal to each other; two groups of coplanar and mutually perpendicular butterfly-shaped dipole units are printed on the lower surface of the horizontal dielectric substrate; a fishbone cross-shaped patch is embedded at the intersection of the ends of the dipole units, and there is a gap between the patch and the end of the dipole; a patch with an etched groove line is printed on one side of the vertical dielectric substrate; the patch is connected to the dipole; the microstrip line on the upper surface of the horizontal dielectric substrate is connected to the inner conductor of the coaxial feed line, and the dipole is connected to the outer conductor of the coaxial feed line; the fishbone cross-shaped patch is in contact with the cross-shaped metal wall. The present invention realizes high polarization isolation and low cross-polarization of the dual-polarization tightly coupled ultra-wideband phased array in a lower frequency band without the need for a complex feeding network.

The invention discloses an electromagnetic compatibility test data automatic acquisition and analysis method and system. The method comprises the following steps: automatically acquiring electromagnetic compatibility test data as an input signal and extracting a target signal; respectively extracting an amplitude component and a change rate component of the target signal, combining to obtain a complex eigenvalue, and performing time integration on the complex eigenvalue to obtain an eigenvector component of the target signal; dividing a frequency space into a low-frequency band and a high-frequency band, and calculating the power density of each frequency point of the target signal in a segmented manner; and carrying out quantitative analysis on the electromagnetic compatibility to obtain an electromagnetic compatibility score. According to the method, the target signal can be accurately extracted from the mixed input signal in real time, the multi-dimensional features are extracted from the target signal, the time domain and frequency domain features of the target signal are comprehensively described, the frequency spectrum power density is accurately calculated in a segmented and adaptive manner, the accurate quantitative analysis of the electromagnetic compatibility level is realized, and the accuracy of the electromagnetic compatibility is improved. And the accurate evaluation requirements of different test scenes on the compatibility level can be met.

The invention provides an adaptive coordination method for dynamic droop parameters of heterogeneous battery modules, which comprises the following steps of: identifying transfer function parameters of each heterogeneous module in real time, and solving the problem of pole alignment of different orders of systems by adopting a virtual pole supplementation technology; based on a modal decoupling theory, decomposing a multi-objective optimization problem into three independent sub-problems of low-frequency-band SOC equalization, middle-frequency-band power regulation and high-frequency-band transient suppression; multi-band parallel gradient projection optimization is realized through a pre-calculation constraint feasible region and a versioning synchronization mechanism, and thread competition is effectively avoided; and the fusion weight is adaptively adjusted according to the convergence quality of each frequency band, and a coordinated droop parameter is generated. According to the method, the problem that the frequency domain response of the heterogeneous battery module is not matched is fundamentally solved, the technical breakthrough from static pole assignment to dynamic adaptive adjustment is realized, and the stability and efficiency of the heterogeneous energy storage system are improved.

An electronic device performs sub-band decomposition on a to-be-coded audio to obtain a to-be-coded low frequency signal corresponding to a low frequency band and a to-be-coded high frequency signal corresponding to a high frequency band. The device performs compression coding on the to-be-coded low frequency signal to obtain low frequency coded data of the to-be-coded low frequency signal. The device determines high frequency prediction information according to the to-be-coded low frequency signal. The device performs feature extraction on the to-be-coded high frequency signal to obtain high frequency feature information. The device determines high frequency compensation information of the to-be-coded high frequency signal according to a difference between the high frequency feature information and the high frequency prediction information. The device also performs encapsulation processing on the low frequency coded data and the high frequency compensation information to obtain audio coded data of the to-be-coded audio.

The invention discloses a near-fault broadband strong vibration simulation method, which comprises the following steps: S1, data collection and preprocessing: collecting a small vibration record in a research area as a source of an empirical Green function, and simultaneously obtaining information such as a geologic structure and stratum parameters of the area for model construction of a discrete wave number method; s2, correcting an empirical Green function, and selecting records similar to a target earthquake focus mechanism from the collected small earthquake records; and S3, calculating based on a geological structure and stratum parameters of a research area by using a discrete wavenumber method. According to the near-fault broadband strong vibration simulation method, the advantages of the two methods are fused, the description of the discrete wave number method on the medium structure at the low frequency band is accurate, the corrected empirical Green function can consider more actual factors at the high frequency band, accurate simulation of the broadband is achieved, and small vibration records are used as the empirical Green function, so that the simulation accuracy of the near-fault broadband strong vibration simulation method is improved. And information such as a real field effect is included, so that a simulation result is closer to an actual seismic oscillation condition.

A device may include a radome. A device may include a spacer coupled to the radome. A device may include a first antenna element formed on a first printed circuit board (PCB) and configured to be housed by the radome, wherein the first antenna element is a multi-band antenna element comprising: one or more low-band radiating elements, one or more mid-band radiating elements; and one or more high-band radiating elements. A device may include a second antenna element formed on a second PCB and configured to be housed by the radome, the second antenna element comprising one or more WiFi antenna elements. A device may include a third antenna element formed on a third PCB and configured to be housed by the radome, the third antenna element comprising one or more global positioning system (GPS) antenna elements.

The invention relates to the technical field of physical health data analysis, in particular to a teenager physical training method and system based on data analysis, and the method comprises the following steps: dividing a load signal into a low-frequency band, a bandwidth frequency band and a high-frequency band based on the load intensity data in teenager training, analyzing the long-term change trend and fluctuation range of the load of the low-frequency band, and calculating the long-term change trend of the load of the high-frequency band; stability parameters are calculated in combination with bandwidth frequency band signal fluctuation, the high-frequency-band short-time load change rate and change rate distribution are analyzed, and a frequency band distribution parameter set is obtained. According to the invention, through load signal multi-band decomposition and parameterization processing, independent calculation and comprehensive analysis of load characteristics are realized, the dynamic change capture capability is enhanced, and through association of cumulative load and time distribution characteristics, dynamic interaction data support is provided, and load risk points and distribution areas are accurately identified. The intensity, time and frequency adjustment strategies are optimized, load balance and action coordination are achieved, overload and deviation risks are reduced, and the scientificity and controllability of teenager training are improved.

The present invention relates to a millimeter-wave low-pass / high-pass reconfigurable filter, comprising a series-parallel reconfiguration structure, a passband compensation inductor, and a ground-direct connection reconfiguration structure, capable of achieving the interchange of a passband and a stopband of the filter in two modes, reconfigurable output in both high and low bands, low loss at the passband and good mirror signal suppression at the stopband, and hardware reuse. The millimeter-wave low-pass / high-pass reconfigurable filter of the present invention has a simple circuit structure, and is suitable for use in a multi-band millimeter-wave reconfigurable transceiver.

There is provided a ventilation-type silencer that uses a porous sound absorbing material and has high sound deadening performance in a low frequency band. A ventilation-type silencer includes an inlet-side vent pipe, an expansion section that communicates with the inlet-side vent pipe and has a cross-sectional area larger than a cross-sectional area of the inlet-side vent pipe, and an outlet-side vent pipe that communicates with the expansion section and has a cross-sectional area smaller than the cross-sectional area of the expansion section. The ventilation-type silencer includes a porous sound absorbing material that is disposed in at least a part of the expansion section, a back space that is a space in the expansion section formed on a side of the porous sound absorbing material opposite to a flow channel connecting the inlet-side vent pipe and the outlet-side vent pipe, and a partition member that partitions the back space. A region partitioned by the partition member forms an acoustic resonator, and the acoustic resonator is acoustically connected to the flow channel.

According to the thin-layer sound absorption superstructure composite acoustic enclosure and the using method, the acoustic enclosure is composed of the cover plate, the conformal frame, the thin-layer sound absorption superstructures and the porous sound absorption materials, the variety of the thin-layer sound absorption superstructures is not limited to one, and the broadband noise reduction effect can be achieved through the parallel superposition design of the thin-layer sound absorption superstructures and the porous sound absorption materials. Wherein the thin-layer sound absorption superstructure can absorb noise in different frequency ranges of medium and low frequency bands, the porous sound absorption material can absorb noise in medium and high frequency bands, and the working bandwidth of the composite acoustic shield after parallel connection and superposition can cover the low, medium and high wide frequency bands. The thin-layer sound absorption superstructure composite acoustic shield further has the advantages of being high in space utilization rate, high in space adaptability, small in thickness, low in surface density and high in material replaceability. Compared with an existing sound insulation cover, on the premise that the thickness is small and the surface density is low, the working frequency band is wider, the sound insulation effect is better, and the sound insulation cover has wide application prospects in noise control of various mechanical and electrical products.

An antenna assembly may include at least two PCB bases. Each PCB base may include a first multi-band antenna element, and a second multi-band antenna element, formed on each PCB base. The first multi-band antenna element and the second multi-band antenna elements can include one or more low-band radiating elements, one or more mid-band radiating elements; and one or more high-band radiating elements.

The invention relates to the technical field of applied geophysics, in particular to a logging-while-drilling shear wave velocity processing method, device and equipment and a storage medium. The method comprises the following steps: dividing a parameter range and a step length, determining a stratum parameter combination, and taking the stratum parameter combination as a data set sample feature; constructing a frequency dispersion data set according to the obtained data set sample labels; performing data cleaning on the frequency dispersion data set, and correcting error samples in the data set; establishing a neural network, training a frequency dispersion data set, and verifying the feasibility of the model; an inversion objective function is established through a joint inversion method, the shear wave velocity is inversed by adopting a low frequency band, and the mud velocity is inversed by adopting a high frequency band; an optimization method is added, so that the number of forward calculation times in inversion is reduced, and the inversion efficiency is improved; and replacing the current depth point with the next depth point, and returning to execute the optimization method until the transverse wave velocity processing of the full depth section is completed. According to the method, the rapid frequency dispersion correction under the well logging while drilling is realized, the calculation efficiency is improved, and the calculation cost is saved.

The invention relates to the technical field of electric energy meters, in particular to an intelligent electric energy meter with a power saving function. A communication module; the power supply module generates power according to the temperature difference between the surface temperature of the electric energy meter chip and the air temperature in the electric energy meter so as to provide electric energy for the communication module; and the control module is used for respectively adjusting the monitoring sampling mode of the detection module from a low-frequency sampling mode to a low-frequency full-frequency composite sampling mode according to the fluctuation ratio of the electrical load, and adjusting the data transmission mode of the communication module from a periodic transmission mode to an encrypted transmission mode based on the power generation voltage ripple of the power supply module. The signal transmission frequency band of the communication module is adjusted to be a low frequency band; wherein the alternating transmission frequency of single transmission of the periodic transmission mode is determined according to the average power generation voltage of the power supply module. The working stability of the electric energy meter is improved.

The invention provides an active and passive source surface wave frequency dispersion curve inversion method and device, and belongs to the technical field of surface engineering exploration, and the method comprises the steps: obtaining an active source surface wave seismic record and a passive source surface wave seismic record; generating an active source frequency dispersion curve based on the active source surface wave seismic record, and generating a passive source frequency dispersion curve based on the passive source surface wave seismic record; extracting a high-frequency-band frequency dispersion curve in the active source frequency dispersion curve, extracting a low-frequency-band frequency dispersion curve in the passive source frequency dispersion curve, and splicing the high-frequency-band frequency dispersion curve and the low-frequency-band frequency dispersion curve into an active and passive source surface wave frequency dispersion curve; and obtaining a one-dimensional shear wave velocity profile based on inversion of the active and passive source surface wave frequency dispersion curve. According to the method, the active source frequency dispersion curve and the passive source frequency dispersion curve are subjected to joint inversion, so that the technical problems of high solution multiplicity and poor inversion result accuracy of active and passive source surface wave frequency dispersion curve inversion in the prior art are solved.

The invention relates to a seismic frequency broadening method, system, equipment and medium for seismic frequency division and inverse Q filtering, and the method comprises the steps: carrying out the spectrum analysis of post-stack seismic data, and decomposing the original post-stack seismic data of a target interval into frequency division data bodies of different frequency bands through generalized S transformation; based on the deep logging curve, a Q value curve is obtained through estimation by means of a preset Q value fitting formula; establishing a three-dimensional Q-value data volume by using the Q-value curve obtained by fitting and combining a seismic interpretation result; on the basis of the three-dimensional Q-value data volume, performing inverse Q filtering processing on the obtained frequency division data volumes of the medium and high frequency bands, and combining the frequency division data volumes of the medium and high frequency bands after inverse Q filtering processing with the frequency division data volumes of the low frequency bands; and based on the combined post-stack seismic data volume, carrying out seismic frequency expansion by taking an artificially synthesized seismic record as quality control, and carrying out seismic interpretation and sedimentary unit fine description. The method can be widely applied to the technical field of oil-gas exploration and development.

A multi-band antenna includes a reflector that provides a ground plane, a first array of first radiating elements, each of the first radiating elements located on a front side of the reflector and configured to emit first electromagnetic radiation in a low frequency band, a second array of second radiating elements, each of the second radiating elements located on the front side of the reflector and configured to emit second electromagnetic radiation in a high frequency band, and an artificial magnetic conductor (AMC) plane that is located between the reflector and a radiator of the first radiating element and between the reflector and a radiator of the second radiating element. The AMC plane is configured to reflect the first electromagnetic radiation substantially in phase and to reflect the second electromagnetic radiation substantially in antiphase.

The invention discloses a cooperative control method and system for noise reduction and fire prevention of a transformer substation. The method comprises the following steps: determining the acoustic impedance mutation degree of an original composite board according to the frequency and amplitude distribution of target low-frequency noise of the transformer substation; when the acoustic impedance abrupt change degree exceeds an abrupt change threshold value, optimizing a first physical parameter of the original composite board; the heat flow density of the first composite board obtained through optimization is obtained, and if the heat flow density exceeds a fireproof threshold value, a second physical parameter of the first composite board is optimized; obtaining a noise penetration index of the target low-frequency-band noise in the second composite board obtained through optimization, and if the noise penetration index does not exceed a penetration threshold value, optimizing a third physical parameter of the second composite board; and determining final physical parameters corresponding to the acoustic-thermal performance balance point according to the acoustic impedance distribution and the thermal conductivity distribution of the third composite board obtained through optimization so as to adjust the structure of the third composite board. According to the invention, collaborative optimization of sound absorption frequency band characteristics and fireproof performance can be realized, and both noise reduction and fire prevention can reach an ideal state at the same time.

The invention discloses a magnetotelluric signal denoising method and system based on self-supervised comparative learning, and the method comprises the steps: constructing a noisy signal sample, obtaining a noise contour sample and / or a pure signal sample of the noisy signal sample, and training a pre-training denoising model based on a comparative learning framework through the noisy signal sample; a small part of data with labels is taken and sent to the trained pre-training model, values of all layers in the learning framework are fixed and compared, only a regression layer is finely adjusted, and a trained signal-to-noise mapping model is obtained; and finally, inputting the to-be-denoised signal into the signal-to-noise mapping model to obtain a denoised magnetotelluric signal. According to the method, a self-supervised contrast learning framework is introduced into a magnetotelluric signal noise reduction technology, data augmentation is realized through a time domain augmentation mode and a frequency domain augmentation mode, strong interference in the magnetotelluric signals is effectively removed, slow change information of a low-frequency band of the signals is reserved, and a good noise reduction effect is achieved.