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90 results about "Point source" patented technology

A point source is a single identifiable localised source of something. A point source has negligible extent, distinguishing it from other source geometries. Sources are called point sources because in mathematical modeling, these sources can usually be approximated as a mathematical point to simplify analysis.

Random finite fault source model establishment method

The invention discloses a stochastic finite fault source model establishment method, which comprises the following steps of S1, determining a geometrical shape of a seismic fault based on regional geological data and seismic monitoring data, and estimating a non-planar fault parameter and a fault plane average sliding amount in combination with historical data and an empirical formula; s2, estimating distribution and sliding strength of concave-convex bodies and obstacles on the fault surface according to historical seismic inversion data, and obtaining the sliding amount of each sub-fault by randomly disturbing the average sliding amount; s3, the discrete fault plane serves as a sub-fault unit, and after an initial fracture point and the average fracture speed are determined, random fracture initial time conforming to normal or power law distribution is generated based on a random number method; s4, calculating the seismic oscillation time history of each sub-fault by adopting a random point source method, superposing contributions, introducing the influence of a shallow velocity structure V30, and generating a three-dimensional seismic oscillation field; and S5, comparing actual strong earthquake record adjustment parameters, and outputting a multi-risk-level earthquake motion parameter evaluation result after iterative optimization. According to the method, by fusing randomness and empirical data, the simulation precision of the seismic source model on the uncertainty of the seismic process is improved, the influence of the potential maximum-magnitude earthquake possibly occurring in the active fault zone in the future can be effectively estimated, the seismic oscillation simulation precision and the calculation efficiency can be improved, and the method is suitable for engineering structure aseismic design and seismic disaster evaluation.
Owner:JIANGXI TONGJI CONSTR PROJECT MANAGEMENT CO LTD +1

Measurement precision correction method for digital geological compass

The invention relates to a measurement precision correction method for a digital geological compass. The method comprises the following steps: determining the magnetic field stability of a target position according to the difference between total magnetic field intensities in a first interval; determining a magnetic field interference coefficient at the moment according to a difference value between the total magnetic field intensity at each moment and the total magnetic field intensity at the target moment; determining the integrating degree of the point source model at the previous moment according to the difference between the magnetic field interference coefficients at each adjacent moment and the duration of the interval between each adjacent moment and the initial moment; determining a target duration according to the magnetic field interference coefficient in the second interval and the duration of the interval between each moment and the initial moment, and correcting the magnetic field data of each axis of the compass according to the target duration and the difference between the magnetic field data of each axis at the target moment and the magnetic field data of the axis in the first interval; and carrying out azimuth calibration on the compass according to the corrected magnetic field data of each axis and the longitude and latitude of the target position. The method can improve the accuracy of geological survey.
Owner:HULUNBUIR MOUNTAIN GOLD MINING CO LTD

Rapid and accurate tracing and positioning method and system for point source high-risk gas leakage

The invention discloses a point source high-risk gas leakage rapid and accurate traceability positioning method and system, and relates to the technical field of gas leakage source localization, and the method comprises the steps: determining a mesoscale turbulence diffusion model according to on-site geographical environment information and high-risk gas characteristics, the position of the virtual monitoring point is optimized by verifying the validity of the virtual monitoring point in an actual scene; and then batch numerical simulation is carried out to obtain an associated data set, a neural network model is trained according to the associated data set, a leakage source positioning model is obtained, the predicted actual leakage source position is output according to the gas concentration collected by each actual monitoring point, and accurate traceability of the leakage source is realized. According to the scheme, the diffusion phenomenon is accurately simulated through the optimized diffusion model, so that the obtained data is more practical, and the traceability precision is indirectly improved; and based on a machine learning method of an artificial neural network, the correlation between the concentration distribution and the leakage source position is established, and accurate and rapid traceability positioning of the leakage source is realized.
Owner:CHINA SPECIAL EQUIP INSPECTION & RES INST

Method for optimizing geometric parameters of ultrasonic transducer for online thickness measurement of cable insulation layer

The invention provides an optimization method for geometric parameters of an ultrasonic transducer for online thickness measurement of a cable insulation layer, and belongs to the field of ultrasonic transducer optimization design. According to the method, a cable is dispersed into a plurality of spatial positions according to cable vibration characteristics, and the optimization problem of the ultrasonic transducer is formed; decision optimization indexes of the average amplitude, the minimum amplitude, the amplitude variance and the cost of secondary reflection signals at multiple spatial positions are established, then the amplitudes are converted into surface receiving sound pressure, quantitative calculation of the sound pressure is achieved through a distributed point source method, a decision matrix is established, and the surface receiving sound pressure is calculated. And then selecting a relatively optimal transducer geometric parameter scheme by adopting a multi-weight comprehensive approximation ideal solution sorting method. According to the method, the problem of low signal amplitude in the traditional thickness measurement process can be effectively solved, and the construction of a better online measurement system can be supported, so that the development cost and time are reduced, and a new thought is provided for the optimization design of an ultrasonic measurement system in a complex environment.
Owner:GUANGXI UNIV

Gas pipeline leakage heat radiation prediction method based on terrain and temperature correction

The invention relates to a gas pipeline safety protection problem, in particular to a gas pipeline leakage heat radiation prediction method based on terrain and temperature correction. The method comprises the following steps: acquiring pipeline design parameters and surrounding environment data, calculating a gas leakage flow rate Q according to the pipeline design parameters and the surrounding environment data, and calculating a heat release rate Q'according to the gas leakage flow rate Q; constructing a landform correction factor calculation model according to absorption, heat conduction and reflection characteristics of a surface material around the pipeline; importing the landform correction factor calculation model into the basic multi-point source model for iteration until convergence, and obtaining the total radiation intensity obtained by convergence; and correcting the total radiation intensity obtained by convergence based on the difference value between the actual temperature and the standard environment temperature to obtain the final total radiation intensity. The method can accurately predict the thermal radiation intensity distribution of the gas pipeline under the conditions of complex terrains and different environment temperatures, and further accurately assesses the damage range and the influence area of thermal radiation in a fire blast accident.
Owner:CHANGZHOU UNIV

Discrete point source bus set envelope fitting and optimization design method for expanding light source to realize uniform illumination

The invention belongs to the technical field of optical lenses, and particularly relates to a discrete point source bus set envelope fitting and optimization design method for expanding a light source to realize uniform illumination. Dispersing the expansion source into point light sources, and obtaining a cluster bus set based on an accurate mathematical model of the point light sources; according to an envelope principle, selecting an outmost contour including all features as much as possible, and fitting the outmost contour by using a polynomial under a polar coordinate system to serve as an initial generatrix of the light distribution lens; a root mean square error of an irradiance distribution numerical value obtained by running a two-dimensional ray tracing program is used as an evaluation index to optimize and fit various coefficients of a polynomial, finally, the lens suitable for achieving uniform illumination through extended source light distribution is obtained, and the problem that mathematical modeling of an extended source light distribution light path is difficult is solved; through verification, the performance is good, the irradiation uniformity is gradually improved to 92.7% from 76.8% of an initial structure, the edge irradiance gradient is improved to 0.45 from the initial 0.27, and the edge dispersion problem is effectively weakened.
Owner:EAST CHINA JIAOTONG UNIVERSITY

Method for calculating dispersion of point source explosion of pollutants based on local micro-meteorological environment

The present application relates to the field of pollutant diffusion simulation and disaster emergency, in particular to a calculation method of pollutant point source explosion diffusion based on local micro-meteorological environment, comprising the following steps: S1. Data acquisition and preprocessing: obtaining local micro-meteorological data, point source pollutant parameters and terrain data, and performing data preprocessing; S2. Explosion parameter inversion: based on pollutant characteristics, initial release conditions and micro-meteorological environment parameters, key parameters of explosion shock wave and pollutant release are inverted; S3. Micro-meteorological-explosion-diffusion coupling simulation: a coupling model of micro-meteorological field, explosion shock wave field and pollutant diffusion field is constructed to simulate the interaction process; S4. Result output and visualization: the calculation results are sorted and analyzed, key information is output, and graphical display is performed. The present application realizes fine input and dynamic coupling of local micro-meteorological elements, establishes a linkage model of explosion shock wave and local airflow, and constructs a parameter adjustment mechanism for different local scenes.
Owner:XIANGYANG ZHIHANG LOW ALTITUDE TECHNOLOGY (SHENZHEN) CO LTD

Earth surface deformation forward and reverse modeling method and system based on mogi model

The invention provides an earth surface deformation forward and reverse modeling method and system based on a mogi model. The method comprises the steps of obtaining an observation data file and a mogi point source parameter constraint file; determining deformation parameters of observation points from the observation data file, and obtaining regional optimal mogi point source parameters based on nonlinear least square inversion by combining the mogi point source parameter constraint file; position parameters of observation points are determined from the observation data file, mogi forward modeling is carried out based on regional optimal mogi point source parameters, and a theoretical earth surface deformation field is obtained; and calculating a residual index according to the theoretical earth surface deformation field and the deformation observation value of the observation point, and outputting the theoretical earth surface deformation field and the residual index which meet a preset evaluation requirement.
Owner:WUHAN UNIV

Intelligent calculation method and system for space-time heterogeneous aberration

The invention relates to the technical field of calculation imaging, in particular to a space-time heterogeneous aberration intelligent calculation method, system and device and a computer storage medium. According to the invention, the optical sensor is placed on the rear focal plane of the micro-lens array to collect the four-dimensional light field information of the three-dimensional point source, and the sub-aperture image is extracted, so that a rich data basis is provided for aberration modeling. According to the method, scene Gaussian and aberration Gaussian parameters are initialized based on sub-aperture images, the scene Gaussian parameters are transformed by using an S3 Splitting mechanism and projected to a two-dimensional image plane to generate a rendered image, joint optimization is carried out through combination of a spatial domain and frequency domain loss function and an Adam optimizer, and accurate modeling and correction of space-time heterogeneous aberration are realized. And finally, the target scene is directly projected to generate a corrected high-resolution clear image in a Gaussian mode, complex optical hardware is not needed, and the problems that in the prior art, the spatial resolution is reduced, the time resolution is reduced, space-time heterogeneous aberration cannot be processed, and generalization is not high are effectively solved.
Owner:TSINGHUA UNIVERSITY

An Experimental Method for Measuring the Attenuation Coefficient of Broadband Laser Ultrasonic Lamb Waves in Metal Sheets

The present invention discloses a method for actually measuring the attenuation coefficient of broadband laser ultrasonic Lamb waves in metal thin plates, belonging to the field of nondestructive testing. Data acquisition stage: Use a nanosecond laser to set a point source excitation on the surface of an aluminum alloy thin plate, and then use a scanning laser Doppler vibrometer (SLDV) to measure the wave field and collect linear wave field data. Data processing stage: Use the time-frequency analysis of continuous complex wavelet transform to obtain the time-frequency spectrum of the one-dimensional wave field signal. Determine the effective analysis range, including the time upper limit and the frequency upper limit. Extract the amplitude data represented by the intercept line. Attenuation characteristic analysis stage: Extract the peaks of the amplitude data at multiple distance points to obtain discrete points of the amplitude change with distance at a specific frequency. The present invention provides a method for actually measuring the attenuation characteristics of broadband laser ultrasonic Lamb waves. The solution of the attenuation coefficient provides an important theoretical reference for the calculation of the effective detection range and the selection of the filtering frequency of damage scattered waves.
Owner:JIANGSU UNIV

MLESAC and SVD-based coordinate transformation correction method for 3D point cloud space volume identification

The invention relates to a coordinate transformation correction method for 3D point cloud space volume identification based on MLESAC and SVD. The coordinate transformation correction method comprises the following steps: preprocessing original point cloud data; extracting a reference plane, and constructing a mixed probability model through an MLESAC algorithm; calculating an optimal rotation matrix and an optimal translation vector by using the normal vector on the reference plane and the normal vector on the three-dimensional coordinate system and adopting an SVD (Singular Value Decomposition) algorithm; according to the obtained optimal rotation matrix and translation vector, rotation transformation and translation transformation are carried out on all point sources in the source point set P, and the point sources are made to fall on a target plane; and outputting the corrected point cloud, verifying the standard deviation of the distance from the corrected reference plane to the target plane, and ensuring that the standard deviation is close to zero. The beneficial effects of the invention are that through robust registration and accurate transformation, the problem of point cloud space coordinate offset caused by installation deviation of 3D scanning equipment is solved, and the accuracy and efficiency of cargo volume measurement are significantly improved.
Owner:JIANGSU JINGXING TECHNOLOGY CO LTD

An electromagnetic eddy current defect imaging method and system based on parameter level sets

This invention discloses an electromagnetic eddy current defect imaging method and system based on parameter level sets. The method includes optimizing the parameters of an array of eddy current sensors; acquiring data from the metal component under test to obtain eddy current response signals under different excitation-reception conditions; reconstructing the three-dimensional defects based on a parameter level set reconstruction algorithm; setting the location of discrete point sources, the conductivity values ​​of the metal and defects, and the initial coefficient parameters of the basis functions; inputting the eddy current response signals into the level set reconstruction algorithm model to obtain the defect reconstruction objective function based on the parameter level set; calculating the Jacobian matrix and iteratively solving the objective function using the Gauss-Newton method, performing iterative updates, and determining whether the defect reconstruction has converged based on whether the deviation between the reconstruction results before and after the iteration is less than a threshold; and obtaining the final defect imaging result. This invention is easy to implement and does not require a mechanical scanning device; it can acquire information on internal surface defects of metal components through computational imaging.
Owner:TSINGHUA UNIVERSITY

Method for identifying and quantifying atmospheric carbon monoxide plume based on multi-source satellite cooperation

The present application provides a multi-source satellite cooperative-based atmospheric carbon monoxide plume identification and quantification method, comprising: training a ViT model using TROPOMI data to realize global CO plume intelligent rough screening, and generating a first-level mask by SAM after detecting an event; introducing GaoFen-5 AHSI data for a first-level event, performing matching filtering to invert a CO enhancement field and driving SAM to generate a second-level mask; introducing WorldView-3 data for a second-level event, inverting a CO enhancement field through a logarithmic radiation ratio and driving SAM to generate a third-level mask. Finally, according to the resolution of each level of satellite, the IME method is used to estimate the emission rate of each level of point source. The present application constructs a three-level cooperative automatic detection system of 'global scanning-regional detailed investigation-local precise investigation', effectively improves the automation level and attribution ability of CO point source detection, and is suitable for emission verification of key industries and facilities.
Owner:ANHUI UNIV

Round pipeline electric field reconstruction method and device based on mirror image method ray tracing and medium

The invention relates to the technical field of channel modeling, and particularly discloses a circular pipeline electric field reconstruction method and device based on mirror image method ray tracing and a medium, and the method comprises the steps: building a multi-path model through a mirror image method, setting the radius a of a circular pipeline, the coordinates # imgabs0 # of a transceiver at any position in the circular pipeline and the reflection frequency i, all propagation paths of a geometrical optical propagation model in a two-dimensional polar coordinate system are obtained, the electric field intensity is calculated, the circular waveguide function is calculated, the intensity component of each mode of the circular waveguide at different positions is calculated, the intensity component of each mode of the circular waveguide is calculated, the intensity component of each mode of the circular waveguide is calculated, the intensity component of each mode of the circular waveguide is calculated, the intensity component of each mode of the circular waveguide is calculated, the intensity component of each mode of the circular waveguide is calculated, the intensity component of each mode of the circular waveguide is calculated, the intensity component of each mode of the circular waveguide is calculated, and electric field reconstruction is carried out to obtain field distribution E 'Rx (rho, phi, z) at any position in the circular pipeline. According to the method, a geometrical optical model related to circular reflection is established and combined with a circular waveguide model, electromagnetic wave propagation characteristics between point sources at any position can be obtained, and fluctuation of path loss under the multi-mode condition can be explained.
Owner:SOUTHWEST JIAOTONG UNIV

Ship underwater water pressure field depth conversion method and system

The invention discloses a ship underwater water pressure field depth conversion method, which comprises the steps of constructing a ship electrostatic field conversion model based on a point charge model; the influence of the interface effect on a ship pressure signal under the shallow sea environment condition is equivalent to the influence of the interface effect on a ship corrosion related electrostatic field, and a model considering the influence of the medium effect on the ship electrostatic field is established; according to the electrostatic field model, a parallel equivalent source is constructed for a ship water pressure field along the longitudinal directions of a port and a starboard of a ship body based on a source-sink model, and a three-dimensional flow field problem is converted into an equivalent source model distribution problem; establishing a pressure signal inversion method of a point source on the basis of considering the influence of an interface effect on a ship pressure field signal and a source-sink model; the pressure signal model is solved, and then the pressure value of any field point is inverted; a multi-source coupling inversion system with physical interpretability is established, and the signal reconstruction precision under different water depth conditions is remarkably improved by introducing a constraint optimization algorithm; and the actual engineering requirements are met.
Owner:NAVAL UNIV OF ENG PLA

Method for automatically identifying plumes of large point sources of emissions around the world based on satellite data

The application provides a method for automatically identifying smoke plumes of global large point sources based on satellite data, which is based on the column concentration data retrieved by high-resolution satellite remote sensing, selects the region around the global large point source as the research region, and obtains the local concentration enhancement data by deducting the background concentration from the original column concentration. The best global segmentation threshold in the research region is obtained, and the median of the foreground pixels is further taken as the final threshold. The pixels greater than the final threshold in the concentration enhancement image are recorded as the final pixel group, and the information of the final pixel group is traversed to screen out the initial screening plume pixels that meet the conditions, so as to screen out the plume pixels that meet the conditions. The retrieved global large point source emission plume is artificially identified, and the false positive plume is removed, so that the global large point source pollution gas emission smoke plume is finally obtained. The application can automatically identify the emission plume of the preset global emission point source during satellite observation.
Owner:ANHUI UNIV

Method and system for generating mapping table of interaction positions between crystal bars and gamma photons

The present invention provides a method and system for generating a mapping table of the interaction position between a crystal bar and gamma photons. By continuously mapping a crystal array with a point source or a general source, calculating the signals received by PMTs, and obtaining a scatter plot reflecting the interaction position of coincidence events. After removing the singular points in the two-dimensional position spectrum through digital processing, the local maximum algorithm is used for the two-dimensional position spectrum to estimate the center position of each crystal bar, and the data is binarized to obtain a binarized position map. The Euclidean distance from each pixel point to the nearest bright point is calculated for the binarized position map to obtain a distance distribution map. The local maximum values of the distance distribution map are obtained along the X direction and the Y direction respectively to divide the boundary positions of each crystal bar. In this way, each region corresponds one-to-one with the crystal bar array, and then the position mapping table of the system is determined. This method can cover all positions and there will be no divided dead zones.
Owner:BEIJING TOP GRADE HEALTHCARE MEDICAL EQUIP CO LTD

A method and device for small target infrared diffusion imaging based on point source blackbody

The present invention discloses a method and device for infrared diffusion imaging of small targets based on a point source blackbody. First, based on the principle of small target infrared imaging diffusion, a small target diffusion imaging model is constructed to obtain a theoretical diffusion area that varies with distance. The constructed small target diffusion imaging model is calibrated based on dynamic test performance to obtain a small target diffusion calibration area. The small target diffusion calibration area is then compared with the actual diffusion area of ​​the small target measured to verify whether the derived diffusion calibration area conforms to the small target imaging diffusion size. This method and device overcome the problem in the prior art that the target imaging principle is not suitable for small target imaging ambiguity. It can effectively improve the accurate measurement of small target imaging size and provide a testing basis for target recognition in future infrared imaging systems.
Owner:AEROSPACE INFORMATION RES INST CAS

Space camera point source transmittance test device and method based on reverse light path principle

The device and method for testing the point source transmittance of a space camera based on the principle of reverse light path belongs to the field of stray light testing technology, and specifically relates to the stray light test of a space camera; it solves the problem that the test device is expensive and the test accuracy and test threshold are affected by stray light in the existing stray light test of large-aperture space cameras; the device includes: a light energy detector, a flat surface light source, a lens fixture to be tested, a darkroom, and a test tank; the light energy detector is used to parse the complete PST curve in the direction of the light path from the flat surface light source to a given optical entrance and then to infinity. The device and method for testing the point source transmittance of a space camera based on the principle of reverse light path are suitable for testing the point source transmittance of a space camera.
Owner:CHANGGUANG SATELLITE TECH CO LTD

Gamma detector efficiency calibration method and device based on numerical integration

The invention provides a gamma detector efficiency calibration method, device and equipment based on numerical integration, a medium and a program product. The method comprises the following steps: acquiring point source efficiency spatial distribution of a gamma detector; voxelizing the body source model of the to-be-detected body source to obtain a plurality of voxels; obtaining position efficiency corresponding to each voxel based on matching of the position information of each voxel and a point source position in point source efficiency space distribution; obtaining the distance from each voxel to the surface of the body source model in the ray direction pointing to the detection center of the gamma detector from each voxel, so as to obtain the attenuation length of each voxel; obtaining voxel efficiency of each voxel based on the attenuation length and the position efficiency of each voxel and the material attenuation coefficient of the to-be-measured body source; and processing the voxel efficiency of multiple voxels based on a passive efficiency calibration method of numerical integration to obtain the detection efficiency of the gamma detector on the to-be-detected body source.
Owner:NUCTECH CO LTD

A method for correcting the measurement accuracy of a digital geological compass

The application relates to a measurement precision correction method for a digital geological compass. The method comprises the following steps: determining the magnetic field stability of a target position according to the difference between the total magnetic field strengths in a first interval; determining the magnetic field interference coefficient of each moment according to the difference between the total magnetic field strength of each moment and the total magnetic field strength of a target moment; determining the point source model fitting degree of a previous moment according to the difference between the magnetic field interference coefficients of each adjacent moment and the time length interval between each adjacent moment and an initial moment; determining a target time length according to the magnetic field interference coefficients in a second interval and the time length interval between each moment and the initial moment, and correcting the magnetic field data of each axis of the compass according to the difference between the magnetic field data of each axis of the target moment and the magnetic field data of the axis in the first interval and the target time length; and performing azimuth calibration on the compass according to the corrected magnetic field data of each axis and the latitude and longitude of the target position. The method can improve the accuracy of geological measurement.
Owner:HULUNBUIR MOUNTAIN GOLD MINING CO LTD

Tunnel surrounding rock seismic wave rapid simulation method and device, electronic equipment and storage medium

The invention discloses a tunnel surrounding rock seismic wave rapid simulation method and device, electronic equipment and a storage medium, and the method comprises the steps: decomposing a point seismic source function into a series of Gabor basis function linear expression forms, and obtaining a Gaussian wave packet in a Cartesian coordinate system for describing the propagation characteristics of seismic waves in a specific direction; calculating a Gaussian wave packet phase term and an amplitude term according to kinematics ray tracing and dynamics ray tracing, a given speed parameter model and a complex number initial value to obtain propagation characteristics of a single Gaussian wave packet at a single angle; repeating the propagation calculation process of the single-angle single Gaussian wave packet according to a set angle interval in a pre-selected angle range to obtain propagation characteristics of multiple multi-angle Gaussian wave packets; and superposing the propagation characteristics of the multiple Gaussian wave packets at multiple angles to obtain a point source wave field simulated by the Gaussian wave packets in a pre-selected angle range. The rapid simulation method has the advantages of high simulation precision, high calculation efficiency, small memory occupation, directivity and the like.
Owner:CHINA RAILWAY CONSTR HEAVY IND

A method, system, device and medium for simulating Rayleigh surface waves from high-speed railway earthquake sources

The present invention relates to a method, system, device and medium for simulating Rayleigh surface waves of a high-speed railway earthquake source, and belongs to the technical field of numerical simulation of earthquake waves. A high-speed train is a moving line source in a fixed direction. Based on the train moving load model, the loads applied by the four pairs of axles of each carriage to the sleepers under the track are taken as point sources, and the moving line source is decomposed into a superposition of a series of point sources. Considering the elastic effect of the track rails, a time function of the high-speed railway earthquake source is constructed based on the Euler-Bernoulli elastic beam theory. Considering the absorption and attenuation of seismic waves by the underground medium, the staggered grid finite difference method is used to solve the Kelvin viscoelastic wave equation, and at the same time, considering the free surface boundary, the wave field of the earthquake Rayleigh surface wave excited by the high-speed railway moving earthquake source is numerically simulated. It provides the basis and data for the subsequent waveform inversion based on the high-speed railway earthquake source and the inversion of the high-speed railway earthquake source surface wave dispersion curve.
Owner:CHANGAN UNIV

An analytical method for the reflection coefficient of acoustic waves excited by a fluid-porous solid interface seismic source

An analytical method for the reflection coefficient of acoustic waves excited by a fluid-porous solid interface seismic source, including Step 1: deriving the general forms of the potential functions of the fast and slow longitudinal waves and the transverse wave excited by a point source in a porous solid medium; Step 2: using the fluid-porous solid boundary conditions and the relationships between displacement and displacement potential, and stress and strain, to derive the equation relationships between the potential functions of the incident acoustic wave, the reflected acoustic wave, the transmitted fast and slow longitudinal waves, and the transmitted transverse wave excited by a point source; Step 3: solving the displacement fields of the incident and reflected acoustic waves in the fluid medium at the fluid-porous solid seabed interface excited by a point source; Step 4: deriving the analytical equation for the reflection coefficient of acoustic waves excited by a point source at the fluid-porous solid seabed interface. It can accurately characterize the reflection characteristics of acoustic waves excited by a point source at the fluid-porous solid seabed interface, and is of great significance for seabed sound field simulation, underwater target detection, and seabed resource exploration.
Owner:OCEANOGRAPHIC INSTR RES INST SHANDONG ACAD OF SCI +1

Optical imaging using multimode waveguides and lenses

PendingCN122663505AWaveguideOptic system
An optical system includes a multimode waveguide having a non-circular cross-sectional core for transmitting light and a lens optically coupled to the multimode waveguide. The lens directs light from one or more point sources into the multimode waveguide so that the light is transmitted in one or more modes of the multimode waveguide. After transmission, the light is detected at one or more detectable points. In some cases, a back-end lens is configured to receive light output from the multimode waveguide. The back-end lens directs the light to one or more detectable points. In some cases, the front-end lens directs light from two or more point sources to the multimode waveguide at different angles with respect to a propagation axis of the multimode waveguide so that the light is transmitted via two or more different modes of the multimode waveguide, respectively.
Owner:MIRROR GUIDE IMAGING TECHNOLOGY CO LTD

Interference correction method and system for arc rail far-field support of half-curved knife device

The invention provides an interference correction method and system for a far-field support of an arc rail of a half-curved knife device, and relates to the field of wind tunnel test data processing, and the method comprises the steps: taking the arc rail as a finite-length arc section curve source around the rotating center of the half-curved knife device, and constructing a mathematical model through a basic formula of the induced velocity of a curve source micro-section to a model region; configuring characteristic parameters of the mathematical model; according to the characteristic parameters, calculating the actual wind speed and the airflow deflection angle after the model point is disturbed by the point source; carrying out aerodynamic characteristic correction according to the actual wind speed and the airflow deflection angle; the aerodynamic characteristics include velocity pressure, airflow deflection angle parameters, axial static pressure gradient and component additional influence. According to the invention, interference correction can be carried out on the arc rail far-field support of the half-curved knife device, so that the accuracy of test data is further improved.
Owner:LOW SPEED AERODYNAMIC INST OF CHINESE AERODYNAMIC RES & DEV CENT

Phase contrast microscope, phase shift quantitative imaging method, system and storage medium

The present application discloses a phase contrast microscope, a phase shift quantitative imaging method, a system and a storage medium. The microscope includes a dot matrix target ring light source, a pupil aperture, a sample stage, a zone plate objective lens, a dot matrix phase shift ring and a detector arranged in sequence. In the present application, the dot matrix target ring light source is imaged on the dot matrix phase shift ring by the zone plate objective lens, and each point source image has a uniquely corresponding phase filtering point on the dot matrix phase shift ring. Since the point source image and the phase filtering point are relatively small, after the sample is placed, most of the low-order diffracted light can pass unobstructed beside the phase filtering point, thereby maximizing the elimination of the cause of halo artifacts. Combining with a simple phase shift imaging method, the purpose of phase shift quantitative imaging is achieved.
Owner:INST OF HIGH ENERGY PHYSICS CHINESE ACAD OF SCI

Long focal length large field of view object side scanning optical system based on single point source detector

ActiveCN116107082BSustainable buildingsOptical elementsSingle point sourceSpectral bands
The application relates to a long-focus large-view-field object scanning optical system based on a single point source detector, and belongs to the optical field.The application comprises a scanning mirror group, a turning mirror, a filter, a field stop and a point source detector; the scanning mirror group comprises a main mirror, a secondary mirror and a small mirror; light of a detected target is irradiated onto the main mirror, is reflected and converged by the main mirror, is reflected by the secondary mirror, is reflected by the small mirror, is reflected and converged by the turning mirror, is transmitted through the filter and the field stop, and is irradiated onto a target surface of the point source detector; and the scanning mode of the scanning mirror group is swing scanning or 360-degree full-view field scanning at high speed.The application improves the farthest detectable distance of the system and the working efficiency of the system, improves the scanning speed and stability of the system, has simple system structure, small volume, good stability, low cost, high detection sensitivity, high reflectivity, a wide spectral band, multi-spectral detection capability and improved contrast of a detection signal.
Owner:CHINA FORESTRY STAR BEIJING TECH INFORMATION CO LTD