1320 results about "Acoustic speed" patented technology

The invention discloses an underwater vision-inertia-acoustic odometer positioning method fused with a DVL, and belongs to the technical field of robot navigation positioning. According to the method, firstly, an underwater image acquired by a camera and carrier motion data acquired by an IMU and a DVL are used as input information to carry out time alignment and space coordinate system conversion; performing feature point extraction on the image to construct a visual re-projection residual error, and dynamically adjusting a weight ratio of visual information based on the number of feature points and the re-projection residual error; calculating IMU data increment between adjacent frames based on pre-integration to construct an inertial residual error; calculating the displacement change between image frames according to the speed information measured by the DVL to construct a DVL residual error; establishing a nonlinear least square optimization function based on Bayesian maximum posteriori estimation; vision, inertia and acoustic speed measurement data are fused at the rear end through a sliding window mechanism, a multi-constraint joint optimization model is constructed, and the robustness and accuracy of a vision-inertia-acoustic odometer system in the underwater environment are improved.

The invention discloses a bolt pre-tightening force intelligent monitoring method and system based on acoustic characteristics, and relates to the technical field of structure monitoring, and the method comprises the steps: synchronously obtaining three types of acoustic characteristic data of resonance characteristics, sound velocity ratio and nonlinear characteristics, carrying out the interactive calibration, and generating a credibility evaluation result; according to a credibility evaluation result, dynamically adjusting weight coefficients of the three types of acoustic characteristic data in a pre-tightening force calculation weight distribution strategy; inputting the weighted three types of acoustic characteristic data into a staged fusion model by adopting a staged fusion strategy to carry out pretightening force joint calculation; and establishing a long-term monitoring database, and according to deviation analysis of historical monitoring data and a real-time resolving result, updating acquired acoustic characteristic data parameters and a weight distribution strategy to form a closed-loop calibration mechanism. The technical problems of poor dynamic adaptability of multi-source acoustic characteristic data and calculation error accumulation in bolt pre-tightening force monitoring under complex working conditions are solved.

Aspects of this disclosure relate to acoustic wave devices on stacked die. A first die can include first acoustic wave device configured to generate a boundary acoustic wave. A second die can include a second acoustic wave device configured to generate a second boundary acoustic wave, in which the second die is stacked with the first die. The first acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode on the piezoelectric layer, and high acoustic velocity layers on opposing sides of the piezoelectric layer. The high acoustic velocity layers can each have an acoustic velocity that is greater than a velocity of the boundary acoustic wave.

A pore pressure prediction method for fine-grained hybrid sedimentary rock based on variable P-wave velocity includes: carrying out a P-wave velocity test of rock under different effective stresses, determining a function form of the relationship between acoustic velocity and effective stress, fitting the parameters in the function by optimization, and establishing an evaluation model of effective stress influence term by lithology. According to the measured formation pressure data and the effective stress influence term model, the acoustic velocity background value is deduced, the logging curve is preferred, and the acoustic velocity background value logging evaluation model is established. According to the logging curves of DT and DEN, combined with the lithology identification results, the acoustic velocity background value is calculated, and then the effective stress of the formation is obtained, and then the pore pressure is determined according to the overburden pressure.

The invention discloses a coastal sound tomography data assimilation method based on stream function fitting. The method comprises the following steps: arranging a coastal sound tomography system, obtaining underwater sound data containing observation domain hydrological information, carrying out correlation peak extraction, and calculating to obtain a sound ray mutual return transmission time difference; scanning topographic information of an observation domain and temperature and profile data between stations, inputting the topographic information and the temperature and profile data into a sound velocity model for sound ray simulation, determining an actual propagation path of sound rays, and inverting path average flow; constructing a three-dimensional unstructured grid of the observation domain, and determining a projection relation between an actual propagation path of sound rays and the grid; establishing a state transition matrix by taking a sound ray path average flow as an observation vector of extended Kalman filtering and taking a coefficient matrix of a flow function least square fitting ocean numerical pattern calculation result as a state vector; and assimilating and updating by using an extended Kalman filtering algorithm, and obtaining an optimized flow field. According to the invention, the observation precision, the resolution and the spatial range of the coastal flow field can be obviously improved.

The invention relates to the technical field of medical image reconstruction, and discloses an ultrasonic tomography enhanced opto-acoustic image reconstruction method, which comprises the following steps that: each array element of a transducer sequentially transmits an ultrasonic signal, other array elements receive the ultrasonic signal, and sound velocity information of a tissue is reconstructed through an ultrasonic tomography technology; irradiating the tissue by using pulse laser, and receiving a photoacoustic signal emitted by the tissue by using a transducer; and establishing a linear equation set to describe the relationship between the initial pressure distribution and the photoacoustic signal, and iteratively solving to reconstruct the initial pressure distribution. Dual-mode imaging of ultrasonic tomography and photoacoustic tomography is realized by using the same equipment, a sound velocity distribution diagram and a photoacoustic original signal are respectively obtained, and sound velocity information of ultrasonic tomography is introduced into reconstruction of a photoacoustic image, so that the reconstruction quality of the photoacoustic image is effectively improved. Experiment and simulation results show that the method has high operability and application effectiveness.

The invention provides a smoothed particle fluid dynamics simulation wave impact structure boundary force processing method, which comprises the following steps: S1, initializing the speed, density and position of particles by establishing a numerical model; s2, dividing fluid particles and boundary particles; s3, calculating and correcting the density and speed variation of the particles according to the hydrodynamic equation and the boundary rejection effect; s4, calculating the pressure and the speed of boundary particles through a Schelerd interpolation method, and reflecting the interaction between the fluid and the solid; s5, based on the pressure and the position of the boundary particles, calculating the pressure intensity, obtaining the stress and the torque of the structure, and updating the degree of freedom; and S6, updating the particle state and entering the solution of the next time step. According to the method, when the influence of the boundary force is determined, the influence of the relative speed of fluid particles and wall surface particles is considered, meanwhile, the maximum speed in a flow field is approximately replaced by the artificial sound velocity, and the purposes of accurately simulating the interaction process of the ocean wave-ocean engineering structure and ensuring the stability of numerical simulation calculation are achieved.

The invention relates to the technical field of bolt tightening, and provides an intelligent bolt tightening control method and system based on axial force measurement. Comprising the steps of collecting bolt identification and process parameter data, collecting temperature measurement data, and obtaining sound velocity compensation parameters and elastic modulus compensation parameters. And zero-load preloading data are collected and processed to generate zero-load baseline data, and a self-calibration model is obtained. Axial force data and ultrasonic echo data are collected, and an axial force fusion estimation result is obtained. And comparing an axial force fusion estimation result with target axial force data. And when in the target interval, fine twisting control is carried out based on model predictive control and a micro-stepping strategy, and the controllable damping unit is driven to carry out energy absorption and stopping. And acquiring an axial force fusion estimation result when the target axial force is reached, processing the data in the holding stage to obtain an axial force rebound check result, and if the axial force rebound check result exceeds the limit, performing secondary twisting control. According to the scheme, refinement and traceability of the bolt tightening process are achieved.

The invention relates to a two-parameter calibration-free pulverized coal temperature measurement method based on acoustic tomography, and the method comprises the following steps: 1, arranging a plurality of loudspeaker and microphone combination modules around a measurement field domain for transmitting and receiving acoustic signals, and forming an annular acoustic sensor array; step 2, multi-frequency sound transit time and amplitude attenuation measurement; 3, constructing a tomography inversion problem model of sound velocity and sound attenuation distribution; 4, respectively realizing tomography inversion of sound velocity and sound attenuation distribution through an improved joint iterative reconstruction method SIRT, and solving pulverized coal accumulation slowness and sound attenuation coefficient distribution under each frequency; 5, calculating a corresponding multi-frequency complex wave number through the multi-frequency slowness and the sound attenuation coefficient in each grid; step 6, constructing a temperature decoupling model of a complex wave number; and 7, regarding the temperature decoupling model of the complex wave number as a nonlinear objective function optimization problem, establishing a nonlinear objective function, and performing parameter decoupling and temperature calculation.

An underwater acoustic sensor network node positioning error correction method combined with acoustic velocity inversion, which method relates to the technical field of acoustic velocity inversion. The method comprises: deploying an acoustic source point and underwater acoustic sensor nodes which are at fixed positions, the underwater acoustic sensor nodes collecting acoustic velocity data sent by means of the acoustic source point, and by means of acoustic velocity data at different underwater acoustic sensor nodes, using an acoustic velocity field inversion algorithm to construct an acoustic velocity field model; collecting real-time acoustic velocity data at the different underwater acoustic sensor nodes, and obtaining acoustic velocity characteristic information at the different underwater acoustic sensor nodes and water characteristic information at the different underwater acoustic sensor nodes; performing comprehensive analysis on the acoustic velocity characteristic information and the water characteristic information, and evaluating the positioning accuracy of the acoustic velocity field model in respect of the underwater acoustic sensor nodes; and comparing quantized positioning accuracy results for the underwater acoustic sensor nodes with a preset threshold, and when there is a relatively large error in the positioning accuracy, generating an error signal. The method is conducive to improving the precision of underwater acoustic wave propagation and the accuracy of underwater acoustic sensor network node positioning, and evaluating the positioning accuracy of an acoustic velocity field model in respect of underwater acoustic sensor nodes.

The invention belongs to the technical field of insulation board detection, and particularly relates to an intelligent detection method and device for the bonding area ratio of an insulation board, and the method comprises the steps: collecting an infrared image of an external insulation system of a building external wall, determining a plurality of segmentation thresholds according to local regions with different sizes of pixel points, obtaining a temperature characteristic value according to the size relation between the pixel value of the pixel point and each segmentation threshold value, dividing the infrared image into a plurality of super-pixel blocks according to the pixel value and the temperature characteristic value, and calculating the temperature anomaly degree according to the number of all the super-pixel blocks contained in each heat insulation board and the concentration trend and difference of the pixel value. And determining the bonding strength of the target insulation board according to the position and area ratio of the target sub-block of which the sound velocity is within the sound velocity range of the bonding part and the bonding state is bonded in the target insulation board of which the temperature abnormal degree is greater than a preset threshold value, and judging whether the target insulation board is qualified by combining the vertical height. According to the invention, the accuracy of insulation board quality detection is improved.

The invention relates to the technical field of underwater acoustic navigation, and provides an underwater acoustic navigation method and system, a medium, equipment and a computer program. The underwater acoustic navigation method comprises the following steps: calculating a sound ray total displacement value by adopting a sound ray tracking algorithm based on underwater carrier position information, transponder position information, and one-way propagation time and a sound velocity profile of a signal between an underwater carrier and a transponder; constructing an acoustic navigation observation model based on the underwater carrier position information, the transponder position information, the total displacement value of the sound rays, and depth and elevation anomalies at the underwater carrier; defining a weighting function according to the one-way propagation time and the dynamic value of the signal between the underwater carrier and the transponder; and solving the acoustic navigation observation model and the weighting function to obtain position information and speed information of the underwater carrier for acoustic navigation. According to the method, the navigation algorithm can be optimized from the two aspects of the acoustic navigation observation model and the weighting function, and the accuracy of acoustic navigation is greatly improved.

The invention relates to the technical field of fluid measurement, in particular to a multimode signal fusion and self-adaptive processing ultrasonic flowmeter and a measuring method. The multimode signal fusion and self-adaptive processing ultrasonic flowmeter comprises an ultrasonic transducer, a signal generation driving module, a signal receiving and conditioning module, a control module, a signal processing module, a signal quality evaluation module and a sound velocity calculation and compensation module. According to the method, the time difference method and Doppler method signals are fused, the self-adaptive processing strategy is adopted to improve the measurement precision of the low-flow-velocity fluid and the impurity-containing fluid, the measurement precision of the low-flow-velocity fluid can be remarkably improved, the adaptability to complex fluid is enhanced, the overall measurement reliability is improved, the Doppler method precision is optimized, and the intelligent degree is high.

The invention relates to the technical field of ocean engineering surveying and mapping, and particularly provides an ocean engineering surveying and mapping terrain correction method based on multi-beam sounding. The method comprises the following steps: constructing a tremor-sound velocity coupling model through multi-source data synchronous acquisition, and generating a sound velocity dynamic correction term; fusing the static sound velocity profile, the internal wave disturbance term and the sound velocity correction term, and establishing a time-shifting sound velocity field of spatio-temporal evolution; realizing dynamic space homing calculation through a double-shaft decoupling rotation matrix based on a hull attitude and a time shifting sound velocity field; tunnel effect noise is suppressed by adopting an airspace adaptive filtering technology; the terrain deformation rate is calculated in combination with continuous cycle data, and a deformation threshold value is dynamically set through soil mechanical parameters to trigger graded safety early warning; and outputting the high-precision three-dimensional terrain model without the sound velocity error and the noise interference. According to the method, the problems of geological activity interference compensation deficiency, tunnel effect noise suppression insufficiency, large dynamic environment homing error and the like in traditional surveying and mapping are solved, and the reliability of complex sea area topographic survey is remarkably improved.

The invention relates to the field of civil engineering structure health monitoring, in particular to a subsea tunnel damage intelligent monitoring and identification method based on acousto-optic collaborative perception. The method sequentially comprises the steps of deploying a three-dimensional acousto-optic sensing network, actively detecting sound waves, reconstructing a local sound velocity distribution cloud picture, identifying a sound velocity abnormal region, performing optical fiber response focusing sampling and establishing an intelligent damage diagnosis model. According to the method, the three-dimensional acoustic array and the distributed optical fiber grid are simultaneously deployed in the subsea tunnel structure, functional complementation is realized between the three-dimensional acoustic array and the distributed optical fiber grid, seamless cooperative sensing of crack coarse positioning and strain fine positioning is further realized, acoustic active detection, trigger type optical fiber high-frequency sampling and a temperature-strain decoupling algorithm are adopted, and the positioning precision of the subsea tunnel structure is improved. Seawater noise and thermal expansion interference are effectively eliminated, 'dry cracks' and'water seepage cracks' are accurately distinguished, real-time monitoring is carried out on a subsea tunnel structure, whole-process identification of micro-damage-expansion-failure is achieved, and an active early warning mechanism is established.

The invention relates to the technical field of material mechanical property testing, in particular to a method for measuring residual stress of a metal component. According to the technical scheme, the method for measuring the residual stress of the metal component comprises a working process for measuring the residual stress of the metal component; according to the method, a technical path of multi-modal data assimilation is adopted, and a mechanical release mechanism of a drilling method and an ultrasonic stress measurement technology are deeply fused to calibrate and correct mass sound velocity data obtained by carrying out rapid ultrasonic scanning on the whole component on site, so that the precise measurement of the residual stress state of the metal component is realized, and the measurement precision is improved. According to the method, data authority and high credibility of a drilling method in a key area are reserved, the advantages of high efficiency and wide coverage of full-field measurement of an ultrasonic method are brought into full play, and efficient and accurate stress information is provided on the premise that components are not excessively damaged.

The invention provides a system for improving positioning precision under a complex underwater acoustic channel and an optimization method, and relates to the field of underwater positioning. The system for improving the positioning precision under the complex underwater acoustic channel comprises a time delay estimation module, a sound velocity profile data module, a sound ray correction module, a slope distance value precision module and a precision improvement module, and the time delay estimation module is mainly used for obtaining more accurate time delay data; the sound velocity profile data module is mainly used for acquiring sound velocity profile data of a positioning area. According to the method, a real sound ray path is estimated by using a sound ray correction method, measurement errors of bubbles in water, sound velocity change and position and propagation time are considered, the positioning precision is further improved, and the comprehensive optimization method enables the system to accurately reflect the real position of a target in a complex underwater environment, so that the positioning accuracy is improved. The overall performance of underwater target positioning is remarkably improved, and the actual requirement of high-precision positioning is met.

The invention discloses an array type multichannel acoustic imaging device and an abnormal sound source positioning display method, and the device comprises a main microphone array which is used for collecting sound signals of a target region; the camera device is used for collecting an image of the target area; the thermal imaging device is used for collecting a thermal image of the target area; the first data processing and analyzing module is used for identifying an abnormal sound signal of the target area and preliminarily estimating the position of an abnormal sound source; acquiring sound field distribution of the abnormal sound source and generating a sound field image by using an acoustic imaging algorithm; the second data processing and analyzing module is used for inputting the change rate of the sound wave parameters of the unit area and the temperature into a second neural network model, obtaining the sound velocity of the unit area in the sound field image, calculating the temperature of the unit area, fusing the sound velocity of the unit area with the temperature of the corresponding unit area in thermal imaging and determining the abnormal temperature; and the display screen is used for displaying the sound field image marked with the abnormal temperature. The abnormal sound source can be effectively distinguished and positioned, and the abnormal temperature can be displayed.

Method and system for characterizing a medium by ultrasound. A method for the ultrasonic characterization of a medium comprising a step of generating a series of incident ultrasonic waves, a step of generating an experimental reflection matrix Rui(t) defined between the input emission basis (i) and an output reception basis (u), a step of determining a de-scanned reflection matrix R' of the medium between a virtual input transducer calculated from an input focus of the experimental reflection matrix and a virtual output transducer calculated from an output focus of the experimental reflection matrix, these virtual transducers being at the same depth. The method includes a step of extracting an optimal positional deviation or an optimal speed of sound model from this focal spot image. Figure for the abstract: FIGURE 5

The invention relates to the technical field of metal ultrasonic detection, and discloses a method for performing nondestructive flaw detection on a casting by using ultrasonic waves and a flaw detection system.The method comprises the following steps that rapid modeling and acoustic reference calibration are performed on equipment and a workpiece, and a unified coordinate system, a sound velocity delay reference and an optimal sound beam path are obtained; acquiring and caching multi-view ultrasonic echoes in real time to obtain a high-integrity original data stream; implementing adaptive noise diffusion based on the data stream, and constructing a diffusion data stack matched with scattering characteristics; performing scattering compensation inverse diffusion and super-resolution fusion on the diffusion stack to obtain a high-resolution purified echo image; performing closed-loop regulation and control on image quality indexes, and optimizing scanning parameters in real time; and combining the optimized image and scanning parameters, and adopting a segmentation network and online increment fine tuning to realize defect identification and automatic grading. The system has high resolution, real-time performance and self-adaptive closed-loop control, and the reliability and the accuracy of casting defect detection are remarkably improved.

The invention discloses a hydropower station diversion tunnel longitudinal crack depth detection method, which comprises the following steps: arranging ultrasonic measuring points above and below a diversion tunnel longitudinal crack to obtain a reinforced concrete sound velocity representative value; arranging ultrasonic measuring points within the length range of the crack; performing ultrasonic detection, and judging the depth of the crack through ultrasonic waves; adjusting the position of the ultrasonic measuring point according to the depth of the fracture until the ultrasonic shape is in a suitable state; and calculating the depth of each detection point of the longitudinal crack. According to the technical scheme, by means of the method for detecting the longitudinal crack depth of the reinforced concrete in the diversion tunnel of the hydropower station through the ultrasonic waves, crack depth detection and calculation of the circular tunnel are completed, and in order to judge the development condition and the stability state of the crack, the crack depth can be regularly detected in the overhaul period of a hydropower station generator set; therefore, monitoring of longitudinal crack expansion and extension is realized.

The invention discloses a double-frequency anti-interference ultrasonic water meter and a metering method thereof, and relates to the technical field of fluid metering. A 500kHz sound velocity reference channel is constructed in a self-transmitting and self-receiving mode of a single transducer, the sound path length under solidified pure water is calibrated through a factory, the current water quality sound velocity is calculated in real time in a zero flow state, the zero offset of a 1MHz main channel is dynamically corrected, and a high-precision temperature sensor is omitted. Meanwhile, online water quality diagnosis is realized by utilizing a double-frequency cooperation mechanism: turbidity is quantized according to the amplitude ratio of 500kHz and 1MHz signals (based on the characteristics of high-frequency scattering sensitivity and high low-frequency penetrability), and bubbles are detected according to the time domain volatility of the 1MHz signals; and dynamically optimizing the flow metering precision of the main channel according to a diagnosis result by combining a sound velocity compensation model (the sound velocity is inversely proportional to the turbidity) and a graded bubble compensation model (the sound velocity or the flow is corrected according to the volatility). According to the method, medium interference is effectively overcome, measurement reliability is improved, and real-time monitoring and reporting of basic water quality (turbidity and bubbles) are achieved at low cost.

The invention discloses a polar region adaptive underwater acoustic positioning correction method based on a multi-dimensional environment coupling model, belongs to the technical field of underwater acoustic positioning, is used for polar region underwater acoustic positioning, and comprises the steps of deploying a heterogeneous sensor network, constructing an environment sensing layer and eliminating a sensor drift error. Establishing a three-dimensional sound velocity model, fusing a vortex kinetic equation, a Kriging interpolation algorithm and an adaptive Runge-Kutta method to track a sound ray trajectory; designing a time-frequency double-domain joint detection algorithm, and combining a lattice IIR filter bank to realize multipath suppression; a 9-dimensional robust UKF algorithm framework is constructed, and multi-source data fusion is realized in combination with federated filtering; and terrestrial magnetism matching and a strain energy density early warning mechanism are integrated. Compared with the prior art, the method improves the positioning accuracy and stability, can more accurately predict the sound propagation path, improves the positioning precision, achieves the dynamic real-time calculation, can quickly and accurately process the continuously changing environment data, and is suitable for the complex polar region environment.

The invention provides a multi-scale while-drilling acoustic imaging logging device and method. An eccentric acoustic logging acoustic system and an active transmitting and receiving ultrasonic logging acoustic system are oppositely embedded in the outer side face of a drill collar. The eccentric acoustic logging acoustic system measures radial and circumferential acoustic characteristics of medium and long-distance stratums in an eccentric transmitting and receiving mode; the active transmitting and receiving ultrasonic logging acoustic system measures circumferential acoustic characteristics of a near-well-wall stratum in an up-down transmitting and middle compensation receiving mode; determining real-time azimuth information of rotation of the device by using an azimuth detection module; the main control electronic bin is in communication connection with all the substructures, transmits instructions and obtains sound waves, ultrasonic pulse waves and azimuth information, and sound velocity imaging data of near-well-wall stratums and medium-long-distance stratums are formed. By applying the device, the problems of small detection range, low measurement resolution, poor imaging precision, single measurement information and the like in the prior art can be solved, and comprehensive and fine evaluation on heterogeneity and anisotropy of underground geology and accurate detection on anomalous bodies can be synchronously realized.

The invention provides a surface acoustic wave resonator, a filter and electronic equipment, and relates to the technical field of semiconductors. A piston structure is formed in the tail end area of an electrode finger strip, larger sound velocity difference is achieved by changing the sound velocity of the tail end area of the electrode finger strip, and therefore a transverse mode is reflected in different directions to avoid energy dissipation caused by resonance. And a high-sound-velocity material covers the middle area of the interdigital electrode to form a high-sound-velocity layer, and a sound barrier between the middle area and the tail end area of the interdigital electrode is constructed, so that the propagation of a transverse mode is inhibited, and the effect of inhibiting in-band transverse stray is achieved.

The invention belongs to the technical field of water conservancy monitoring, and discloses a water conservancy water level monitoring device and method, and the method comprises the steps: a monitoring point arrangement module of a monitoring mechanism reasonably arranges the number and positions of monitoring points; the flow velocity monitoring module monitors the water velocity; the meteorological data acquisition module acquires meteorological data; the echo sounder emits sound waves, and the water depth is calculated according to the sound wave propagation time and the sound velocity in water; the pressure water level gauge, the laser water level gauge and the radar water level gauge monitor the water level of water conservancy. The echo data analysis module analyzes the echo data; the comprehensive analysis module comprehensively analyzes the water level; the predictive analysis module predicts a water level trend and potential risks. The water level of water conservancy is monitored through various water level gauges, cross validation and high precision are achieved, and the sediment deposition thickness is accurately calculated by analyzing echo data; the comprehensive analysis module comprehensively evaluates the water level; the prediction analysis module integrates various monitoring equipment data and meteorological data, and predicts the water level trend and potential risks.

The invention belongs to the technical field of underwater positioning, and discloses an underwater single beacon virtual long baseline positioning method and system capable of estimating an unknown sound velocity. The method comprises the following steps: constructing a virtual long baseline array by combining stored dead reckoning data; constructing a virtual long baseline positioning problem by combining the relationship between the underwater acoustic signal propagation time and the position and sound velocity of the AUV; auxiliary variables are introduced, a pseudo-linear positioning equation is obtained based on algebraic conversion, and an AUV position initial solution is obtained based on a weighted least square method; and constructing a second-step linear estimation problem by exploring the relationship between the auxiliary variable and the AUV position, and solving by using weighted least squares to obtain a more accurate AUV position estimation solution. Compared with a single-beacon positioning method which does not consider sound velocity unknown, the method provided by the invention can obtain more ideal position estimation performance, and the practical application capability of an underwater single-beacon positioning system is enhanced.

The invention provides a TF-SAW resonator, a preparation method thereof and a filter, and relates to the technical field of semiconductors. The interdigital electrode comprises piston structures, sub-bus bars and metal bumps, the piston structures are positioned at two ends of the acoustic part, it can be understood that the piston structures are arranged at the tail end areas of the acoustic part on the electrode finger strips, and larger sound velocity difference is realized by changing the sound velocity of the tail end areas; therefore, the transverse mode is reflected in different directions to avoid energy dissipation caused by resonance; on a propagation path of a transverse mode, the sub bus bars and the metal bumps are sequentially arranged, clutter interference is eliminated by causing sound velocity difference, so that clutter mode interference is inhibited to the greatest extent, the Q value is improved, the insertion loss flatness in a passband is improved, and the performance of the TF-SAW resonator is further improved.

The invention provides a calculation method for propagation of underwater explosion shock waves in a non-uniform acoustic flow field, and the method comprises the steps: simulating the propagation of the underwater explosion shock waves in a non-uniform fluid through an axial symmetry calculation model of an underwater explosion load in the non-uniform fluid based on a local discontinuous Galerkin method and a continuity condition; according to the method, a calculation model special for heterogeneous fluid is constructed, and continuous conditions are combined, so that the propagation process of underwater explosion shock waves in a heterogeneous flow field containing a sound velocity discontinuous interface and a sound velocity gradient is effectively simulated. According to the method, the influence of the sound velocity spring layer interface on the underwater explosion shock wave propagation path and the load peak value can be accurately analyzed, and more reliable underwater explosion load data are provided for the action of the submarine near the sound velocity spring layer. According to the invention, the influence of the flow field sound velocity gradient on the underwater explosion load and cavitation characteristics can be effectively studied, and the design and construction scheme of the protection ship and maritime work structure is optimized according to more accurate underwater explosion load input data.

The invention provides a composite material acoustic emission source positioning system and method, and the method comprises the steps: respectively extracting the arrival time of an acoustic wave signal reaching each acoustic emission sensor, and calculating the arrival time difference between every two acoustic emission sensors; taking the time difference of arrival as a known condition, taking an acoustic emission source coordinate as an optimization variable, and combining with a pre-calibrated sound velocity characteristic of the composite material to establish an optimization model taking a root-mean-square error of a theoretical time difference of arrival and an actual time difference of arrival as a target function; and improving an original whale optimization algorithm by using a nonlinear convergence factor and a random initialization strategy, carrying out iterative solution on the optimization model by using the improved whale optimization algorithm, and when a preset iteration termination condition is met, taking an optimal solution output by the optimization model as a positioning result. The positioning accuracy of the composite material generation source is improved, and the positioning difficulty is reduced.