76 results about "Refraction" patented technology

The invention belongs to the technical field of underwater positioning, and discloses an underwater single-beacon Gaussian Newton positioning method and system under a linear sound profile condition. According to the method, underwater acoustic signal propagation time observation noise is modeled into Gaussian distribution, a maximum likelihood estimation problem is constructed, and then the maximum likelihood estimation problem is converted into a nonlinear least square estimation problem; and solving the gradient of the observed quantity to the position coordinates of the AUV based on a chain rule, iteratively solving a nonlinear least square estimation problem based on a Gauss-Newton method, and obtaining the position coordinates of the AUV after iterative convergence. Compared with other single beacon positioning methods which do not consider sound propagation refraction, the method of the invention can obtain a more accurate position calculation result under a linear sound profile condition, and enhances single beacon positioning, especially the practical application capability of the method in deep sea areas.

The invention discloses an acoustic temperature field reconstruction algorithm based on sparse matrix and refraction effect consideration, and belongs to the field of acoustic temperature measurement. The algorithm introduces a sparse reconstruction technology and refraction effect optimization to solve the problems of large reconstruction error of an underdetermined equation set, sensitivity to a measurement error and the like caused by the fact that the number of sound rays is smaller than a grid sectioning number in existing acoustic tomography. The method comprises the following specific steps: dividing a temperature measurement area into N grids, constructing a compressed sensing model through an observation matrix A and a sparse base psi, reconstructing a sparse signal by using an improved generalized orthogonal matching algorithm, namely IMOMP, reconstructing a temperature field through a relationship between sound slowness and temperature, and improving precision by using cubic spline interpolation. Meanwhile, the sound wave refraction effect in the non-uniform temperature field is considered, the sound ray path layout is optimized, the algorithm effectively deals with inverse problem instability, the reconstruction error is reduced, the anti-noise capability is improved, and the method is suitable for complex temperature field reconstruction and has application value for industrial temperature measurement.

The invention discloses an ionosphere advancing type disturbance short wave propagation effect numerical calculation method based on a wide-angle parabolic equation. The method comprises the following steps of 1, background ionosphere generation, 2, TID model establishment, 3, TID refraction index calculation, 4, parabolic equation wide-angle approximation, 5, step-by-step Fourier numerical solution and 6, path propagation loss calculation. According to the calculation method disclosed by the invention, refraction, diffraction and interference effects during short-wave forward propagation during ionosphere TID are considered, the short-wave coverage range can be calculated, short-wave field intensity distribution and path propagation loss can also be calculated, and the calculation method is superior to a traditional short-wave ray tracing algorithm.

The present invention relates to a method for obtaining multi-order refraction times of refracted waves at the coal-rock interface. When the source wavelength is greater than the coal thickness, the refracted waves of adjacent orders are mutually aliased, and it is difficult for conventional deconvolution methods to sparsify them. By taking advantage of the characteristics of high similarity and known order among the refracted waves of each order and drawing on the orthogonal matching pursuit algorithm, the present invention can accurately extract the refraction times of each order from severely aliased refracted wave signals. The present invention takes into account the phase differences among the refracted waves of each order. By constructing a dictionary matrix containing the phase rotation angle, the refracted waves of each order can accurately match the corresponding wavelets, obtaining accurate pulse signals and improving the accuracy of the obtained time points.

The invention discloses an oval scanning laser radar wave refraction correction error correction method, which belongs to the technical field of airborne laser sounding, is used for airborne laser radar underwater topographic survey wave refraction correction, and comprises the following steps of: performing filtering processing on sea surface point cloud by adopting a statistical outlier removal filtering method; and extracting a sea surface gradient normal vector corresponding to each point by adopting an optimized moving least square method, simplifying the measurement process of the oval scanning laser radar to be carried out under a carrier coordinate system, constructing a refraction correction model by utilizing a Snell law and a vector decomposition method, and obtaining a corrected seabed point cloud coordinate. According to the method, the sea surface point cloud data is denoised, the actually measured sea surface point cloud is fitted through the moving least square method, polynomial fitting is replaced with covariance matrix characteristic decomposition, calculation is easy and convenient, polynomial fitting errors are avoided, the process is greatly simplified through vector decomposition calculation, and only a single solution exists.

The invention discloses a negative conical wave-absorbing honeycomb, which comprises a negative conical impedance matching layer, an absorbing layer and a reflecting layer, and is characterized in that the negative conical impedance matching layer, the absorbing layer and the reflecting layer respectively comprise at least one honeycomb layer, and the honeycomb apertures of the negative conical impedance matching layer, the absorbing layer and the reflecting layer are sequentially decreased; the negative tapered impedance matching layer surface includes at least one negative tapered slot. According to the scheme of the invention, when electromagnetic waves are incident to the honeycomb, the negative conical shape design ensures that two surfaces are always in an oblique incidence state in the polarization direction, scattering of the electromagnetic waves is enhanced, reflection is reduced, impedance matching with airwaves is enhanced, the electromagnetic waves are made to be incident into the material to the greatest extent, and the electromagnetic waves are prevented from entering the material to the greatest extent. Multiple times of reflection and refraction of electromagnetic waves in the negative conical structure are increased, electromagnetic wave energy radiated out is effectively reduced, and efficient broadband absorption of the electromagnetic waves is achieved.

The invention belongs to the field of material detection and evaluation, and discloses a phased array-critical refraction longitudinal wave-based plane stress detection method, which comprises the following steps: estimating a material sound velocity range, optimizing a phased array ultrasonic delay rule, obtaining a change curve of different excitation sound velocities and critical refraction longitudinal wave amplitudes, and extracting an optimal excitation sound velocity; critical refraction longitudinal waves are excited in the sample with the optimal excitation sound velocity, and processing such as interpolation and filtering is carried out on signals received by array elements of a receiving probe; obtaining the amplitude and sound time of critical refraction longitudinal waves, and calculating the sound velocity of the critical refraction longitudinal waves and the sound time difference of different array elements for receiving the critical refraction longitudinal waves; establishing the change relation of the critical refraction longitudinal wave sound velocity, the amplitude and the sound time difference along with the stress. According to the method, the critical refraction longitudinal wave acoustic time-stress relation in a traditional stress test method is improved into the critical refraction longitudinal wave acoustic time-stress-array element spacing relation, and the problems that in the traditional method, material adaptability is poor, acoustic time calculation stability is poor, and stress test reliability is low are effectively solved.

The waveplates herein (A) can have high performance across a broad wavelength range and broad range of incident angles; (B) can be thin; and (C) can withstand a high temperature. The waveplates can include ribs 12 on a substrate 11 with a channel 13 between each pair of adjacent ribs 12. Each rib 12 can include the following layers in the following order moving outward from the substrate: a bottom-medium-layer BM (nBM), a high-layer H (nH), then a top-medium-layer TM (nTM). Each rib 12 can be located on a bottom-low-layer BL (nBL). A top-low-layer TL (nTL) can be located on a face TMF of the top-medium-layer TM farthest from the substrate 11. Relationships between indices of refraction of these layers can be nBL<nBM<nH and nTM<nTM<nH.

The invention relates to the technical field of ocean and land geophysical exploration, and particularly discloses a multiple refraction wave suppression method and device, and the method comprises the steps: converting seismic data into a common detection point gather, and obtaining common detection point gather data; performing Radon transformation on the common detection point gather data to obtain Radon domain data, and calculating multi-channel similarity of the Radon domain data in the Radon domain; calculating a weighting function in a multi-refracted wave existence window, and processing the Radon domain data by using the weighting function to obtain processed data; performing Radon inverse transformation on the processed data to obtain a multiple refraction wave prediction model; and the multiple refracted waves are suppressed through a self-adaptive subtraction method. According to the method, the similarity characteristics of the multiple refracted waves in the Radon domain are utilized, weighting processing is carried out in a window where the multiple refracted waves exist, the prediction precision of the multiple refracted waves is enhanced, finally, the multiple refracted waves are eliminated through adaptive subtraction, the multiple refracted waves in seismic data can be effectively suppressed, and the signal-to-noise ratio of the data and the imaging quality are improved.

The invention relates to a multifunctional wavefront regulation and control metasurface based on a dual-frequency transmission type and a method thereof, the multifunctional wavefront regulation and control metasurface comprises a plurality of metasurface units, and each metasurface unit comprises a dielectric layer; the bottom layer is arranged on the lower side face of the dielectric layer and comprises a lower outer opening ring and a lower inner opening ring, and the lower inner opening ring is located on the inner side of the lower outer opening ring; the top layer is arranged on the upper side surface of the dielectric layer and comprises an upper outer opening ring and an upper inner opening ring, and the upper inner opening ring is located on the inner side of the upper outer opening ring; wherein the central axis of the bottom layer, the central axis of the top layer and the vertical central line of the dielectric layer are overlapped, an opening of the lower outer split ring and an opening of the upper outer split ring are symmetrically arranged in a 180-degree mode, and the lower inner split ring and the upper inner split ring are symmetrically arranged in a 180-degree mode, so that various different functions such as OAM wave beams in different modes, wave beam splitting, focusing lenses and abnormal refraction can be realized.

The invention belongs to the technical field of image processing, and particularly relates to a self-adaptive phased array C scanning imaging method for a surface thread curved surface, which sequentially comprises the following steps of: (1) establishing a curved surface coordinate; step (2), generating propagation prior; step (3), executing a step of cTFM imaging; and step (4), executing a step of RPCA decomposition imaging. According to the method, thread appearance point cloud is synchronously collected through a contourgraph and an encoder, a spiral expansion coordinate domain and a curved surface coordinate index table are established through double quaternion spiral expansion, and geometric continuous modeling of the rotating and feeding process is achieved; in the coordinate domain, a propagation prior lookup table containing refraction time intervals is generated based on a rapid propulsion method, and the refraction propagation path of sound waves between the wedge block and the detected body is accurately described.

The application belongs to the field of oil and gas geophysical exploration, and discloses a kind of geophone combination to improve the calculation method of signal-to-noise ratio degree of single shot data, and the signal-to-noise ratio of geophone combination is improved multiple times compared with geophone single point G , the surface wave suppression amplitude value of geophone combination b 1, the refraction wave suppression amplitude value b 2, the reciprocal of the signal-to-noise ratio of geophone combination suppression random interference wave b 3, the amplitude ratio of surface wave and refraction wave k , the surface wave suppression coefficient, refraction wave suppression coefficient and random interference wave suppression coefficient of geophone combination are obtained, and finally the formula of the signal-to-noise ratio improvement multiple of geophone combination compared with geophone single point is obtained.The application is suitable for calculating the degree of signal-to-noise ratio of single shot data improved by geophone combination, the calculation result is clear, the reliability is strong, the calculation method is fast, and the quantitative basis can be provided for the selection of geophone combination number and group distance in seismic acquisition engineering technical design.

The invention provides a variable-frequency phase-change wave-absorbing gasket and a preparation method thereof. The phase-change wave-absorbing gasket comprises a solid wave-absorbing shell and a phase-change wave-absorbing material filled in the solid wave-absorbing shell; the phase-change wave-absorbing material comprises the following raw materials in parts by mass: 30-60 parts of a wave-absorbing agent, 40-70 parts of heat-conducting powder and 5-15 parts of a composite phase-change matrix, and the composite phase change matrix has more than two phase change points. The phase-change wave-absorbing material is composed of the wave-absorbing agent, the heat-conducting powder and the composite phase-change matrix, so that the phase-change wave-absorbing material can be subjected to multi-stage phase change along with temperature change, and reflection, refraction and absorption paths of electromagnetic waves in the material are increased through particle distribution and lattice arrangement change, so that the absorption effect on the electromagnetic waves is enhanced, and the service life of the material is prolonged. The wave-absorbing frequency band of the phase change wave-absorbing gasket is widened; and meanwhile, the phase change wave-absorbing gasket has high heat absorption capacity, heat generated during operation of equipment can be fully absorbed, and the phase change wave-absorbing gasket adapts to application scenes needing efficient heat dissipation.

The present application relates to the field of eutrophication lake water ecological restoration, and discloses a device and system for improving underwater light conditions of a lake. Natural light on the water surface is introduced into the underwater area near the device through refraction and reflection by using a light path system, effectively improving the underwater light intensity. A wave dissipation system is arranged below the light path system to prevent disturbance of the water body and sediments by small waves, to a certain extent, reducing the influence of sediments and resuspension on water transparency, and further improving the underwater light conditions. The light path system, the wave dissipation system and the underwater fixing system are sequentially fixed and connected from top to bottom, and the height of the light path system and the wave dissipation system is adjusted through the underwater fixing system with the rise and fall of the water surface, improving the applicability of the device. The device has the characteristics of simple structure, convenient operation, good performance, easy installation and recycling, etc. It can effectively reduce the adverse effects of insufficient underwater light of the lake and wave disturbance on the growth of submerged plants.

The present application relates to the technical field of nondestructive testing of nuclear power equipment, and provides a nuclear power metal welded joint nondestructive testing method based on ultrasonic phased array imaging and application, comprising calculating the ultrasonic longitudinal wave velocity and transverse wave velocity of the nuclear power metal material; calculating the defect acoustic scattering response distribution under different angles of the organic glass wedge; using an ultrasonic array detection system, identifying bright spot abnormal points in an ultrasonic phased array scanning image and full matrix capture data corresponding to the positions; using a time reversal operator decomposition algorithm to perform signal denoising processing, obtaining denoised ultrasonic array signals; calculating the propagation time of the sound waves emitted by each element of the ultrasonic phased array after refraction through the glass wedge to each grid point, obtaining the Hilbert transform value of each grid point corresponding to the propagation time, and generating an ultrasonic imaging graph of the region; performing delay multiplication superposition and vector coherence factor denoising processing on the imaging data, and obtaining a welded joint nondestructive testing imaging result.

The utility model relates to a device for preventing water surface reflection for fishing. The device comprises a first linear reflection shading plate, a second linear reflection shading plate, a first connecting air column, a first wave light shading plate, a second wave light shading plate and a second connecting air column, the first linear reflection shading plate and the second linear reflection shading plate are arranged on the water surface in a floating mode. The first connecting air column is arranged between the first linear reflection shading plate and the second linear reflection shading plate; the first wave light shading plate is connected with one side of the first linear reflection shading plate and forms an included angle with the first linear reflection shading plate; the water surface wave refraction prevention device is connected with one side of the second linear reflection shading plate, and an included angle is formed; and the second connecting air column is arranged between the first wave light shading plate and the second wave light shading plate. According to the utility model, secondary injury generated when sunlight is reflected on the water surface can be thoroughly blocked, and the reflected light is not only high in intensity, but also easy to cause accidental injury to a human body due to the special propagation path and angle of the reflected light.

The utility model relates to the technical field of silencers, and discloses a labyrinth type silencer which comprises an installation body and a silencing body, the installation body comprises an air inlet hole, a connecting column, an installation shell, a plurality of through holes and two clamping blocks, and the silencing body comprises a silencing outer shell, a plurality of air outlet grooves, a plurality of outer silencing plates, an inner silencing plate, two connecting grooves and a clamping strip. According to the silencer, when sound enters the interior of the silencer body through the air inlet holes, the outer silencing plate and the inner silencing plate in the silencer body form a complex labyrinth type structure, so that gas needs to be turned for multiple times when flowing in the silencer, the complexity of an airflow path is increased, and the noise is reduced. Along with a series of complex paths of airflow in the silencer, sound waves can be gradually attenuated in the multiple reflection and refraction processes, so that the efficient silencing effect is achieved, the silencing efficiency is improved, meanwhile, the smoothness of air flowing is ensured, and using equipment cannot be blocked.

This invention belongs to the field of lidar detection and provides a dynamic underwater target localization method based on lidar. The main steps include: S1: The lidar simultaneously emits a blue-green beam and multiple near-infrared beams surrounding the blue-green beam; S2: Obtaining the pointing angles of the multiple near-infrared beams and the blue-green beam emitted by the lidar, and multiple water surface distance signals received by the lidar from the near-infrared beams returning via the water surface; S3: Calculating the normal vector of the wavefront cell where the blue-green beam intersects with the air-water interface, and determining the position of this intersection point; S4: Calculating the angle of refraction of the blue-green beam through the water surface; S5: Obtaining the three-dimensional coordinates of the underwater target. This invention captures dynamic water surface reflection characteristics using near-infrared beams, accurately obtains wavefront position and angle information, and simultaneously emits blue-green beams for dynamic underwater target detection, thereby achieving high-precision localization of underwater targets.

The invention relates to an integrated navigation precision improvement method based on fused hydrological information, which belongs to the technical field of inertial navigation, and comprises the following steps: S1, based on hydrological information of a target navigation sea area, calculating to obtain a sound velocity profile of the target navigation sea area and wave beam angles of each water layer of the target navigation sea area; s2, based on the sound velocity profile of the target navigation sea area and each water layer beam angle, obtaining a corrected Doppler measurement speed; s3, compensating the corrected Doppler measurement speed based on the beam incident angle after equivalent refraction to obtain a compensated Doppler measurement speed; and S4, fusing the compensated Doppler measurement speed with the inertial navigation speed to obtain a corrected navigation calculation result of the ship or the underwater vehicle. According to the invention, the hydrological environment data and the inertial navigation data are fused, so that the position precision and reliability of the ship or the underwater vehicle during long-time autonomous navigation are greatly improved.

The light refraction demonstration device comprises a supporting mechanism, a test bed, a plurality of light sources and a medium groove, the supporting mechanism comprises a bottom plate, a vertical supporting plate with the lower end fixedly connected with the bottom plate and a vertical mounting plate fixedly connected with the upper end of the supporting plate, and the rear end of the test bed is connected with the front end of the mounting plate. A milky white light screen is arranged at the front end of the test bed, the medium groove is in a semi-cylinder shape and comprises two opposite semicircular walls, an arc wall and a side wall opposite to the arc wall, a groove cavity with an opening located in the side wall is formed in the medium groove, the side wall is located at the upper end, the left end and the right end of the side wall are each connected with a connecting lug, and the connecting lugs are connected with the test bed through screws. And a medium is filled in the medium groove. The problems that the light path phenomenon is hidden and difficult to distinguish and the medium is single are solved.

The invention discloses a satellite-borne laser water depth correction and extraction method considering sea surface waves, and the method comprises the following steps: carrying out the sea surface wave fitting of satellite-borne laser sea surface photon points through employing a smooth spline function, and obtaining the instantaneous wave slope and elevation value of each sea surface photon position; modeling the incident line of each photon point according to the fitting result, and matching the seabed photon points with the sea surface photon points based on the modeling line of the incident light to calculate an initial water depth value; carrying out refraction correction on the initial water depth value according to a wave angle and a photon incidence angle of a sea surface wave fitting result of a corresponding position in combination with marine environment characteristics; and performing geophysical correction on a result after refraction correction to obtain a water depth extraction result based on the average sea level. Through water depth correction considering the sea surface wave angle and the wave height, sounding errors caused by sea surface waves are effectively compensated, and the satellite-borne laser water depth extraction precision and reliability are remarkably improved.

This invention relates to a method, apparatus, electronic device, and storage medium for fast and slow shear wave surface modeling. The method involves: picking up the first arrival time of earthquakes within a preset offset range; dividing the first and second shear wave seismic data into identical ground grids; selecting multiple ground grids and determining the apparent first arrival velocity of each grid, thus determining the refracted wave offset range; determining the first shear wave refraction velocity and the first shear wave delay time at the shot and receiver points; determining the first shear wave surface velocity based on the surface data of the first shear wave seismic data; obtaining the first shear wave surface model based on the first shear wave correlation data and outputting the high-velocity top information of the shot and receiver points; determining the second shear wave refraction velocity and the second shear wave delay time at the shot and receiver points; and obtaining the second shear wave surface model based on the high-velocity top information of the shot and receiver points and the second shear wave correlation data. In other words, this invention achieves synchronous and coordinated establishment of a surface model using fast and slow shear waves.

A waveguide structure. In some embodiments, the waveguide structure, includes: a first waveguide (105), a second waveguide (120), and a third waveguide (125) on a substrate (115). The first waveguide (105) may be at a different height than the second waveguide (120). The waveguides may be configured to cause light to couple between the first waveguide (105) and the second waveguide (120), and between the second waveguide (120) and the third waveguide (125). The first, second, and third waveguides (105, 120, 125) may be composed of respective materials having a first index of refraction, a second index of refraction, and a third index of refraction respectively. The third material may include silicon and nitrogen. The second index of refraction may be greater than the first index of refraction, and less than the third index of refraction.

The present invention discloses a method and apparatus for monitoring seismic waves in underground caverns caused by blasting. The method includes measuring the vibration velocity of the cavern roof along the horizontal direction and / or the longitudinal direction; suspending a right-angle reflector on the roof; emitting and receiving reflected laser light from the floor towards the reflector; acquiring the optical deflection displacement, optical path difference, and time interval of the reflected laser light before and after the blast; and obtaining the vibration velocity along the horizontal direction and the vibration velocity along the longitudinal direction using a velocity formula. Specifically, it utilizes a right-angle reflector to reflect the laser light reflected back towards the roof, and uses the optical path difference and optical deflection displacement generated by the laser light's displacement with the right-angle reflector during reflection to indirectly measure the wave velocity of the roof where the right-angle reflector is fixed; it uses a beam splitter to form two optical paths through refraction and reflection to measure the optical path difference and optical deflection displacement separately; and it uses a convex lens to solve the beam offset caused by optical deflection displacement during comprehensive measurement when measuring the optical path difference. The method is simple in structure, easy to operate, and has strong practicality and wide applicability.

According to the method for measuring the concrete crack through the inclination of the ground penetrating radar based on the mixed medium, the right-angle triangular concrete cushion block filled with the mixed medium is adopted, antenna inclination measurement is supported, and the detection accuracy is improved. And the dielectric constant of the constructed triangular pyramid is variable and is close to the dielectric constant of the concrete structure to be measured, so that the influence caused by refraction and wave velocity change when electromagnetic waves pass through layered media can be reduced. And through a layered medium backward projection imaging algorithm, the adaptability of dielectric constants of the concrete structure and the right-angle triangular concrete cushion block is improved, and the detection effect is improved.

The invention discloses an airborne laser radar sea surface point cloud water depth inversion method, and particularly relates to the technical field of airborne laser radar water depth measurement. The method comprises the following steps: acquiring an echo point cloud and a waveform energy sequence, constructing a three-dimensional point cloud energy matrix, calculating a point cloud local density gradient and a waveform attenuation coefficient, generating a composite scattering characteristic field, constructing a sea surface perturbation constraint model, and performing curved surface fitting on a sea surface echo cluster to obtain a sea surface dynamic fluctuation parameter; performing refraction path reconstruction on the underwater echo cluster to obtain a corrected underwater point cloud depth sequence; calculating a point cloud density change rate in a depth direction, performing coupling operation with the composite scattering characteristic field to generate a water body attenuation compensation coefficient matrix, and calculating a water depth value of the target area through depth statistical regression to obtain a water depth inversion result; the method can effectively weaken the influence of sea surface perturbation and water body scattering on echo signals, and improves the precision and stability of airborne laser radar water depth inversion under complex sea conditions.

The invention relates to the technical field of line fault positioning, in particular to a risk early warning method and an early warning device for a forest fire caused by a power transmission line fault, and the method comprises the steps: obtaining a transient traveling wave signal at each monitoring point, carrying out the phase-mode transformation of the transient traveling wave signal, and extracting a forward traveling wave signal of each monitoring point; the first interference degree, the traveling wave distortion degree, the superposition complexity, the second interference degree, the adjustment coefficient and the corrected decomposition layer number of each monitoring point are determined, and fault positioning is carried out on the power transmission line; and early warning the forest fire risk caused by the power transmission line fault by using a fuzzy reasoning algorithm according to the meteorological environment condition and the vegetation dense condition at the fault position. According to the method, by correcting the number of decomposition layers, the masking interference influence of pulse noise and mixed refraction and reflection traveling waves on traveling wave characteristics is eliminated, the precision of positioning the single-phase earth fault of the power transmission line is improved, and early warning is more accurately performed on the forest fire risk caused by the power transmission line fault.

This invention discloses a method for correcting the water diffuse attenuation coefficient based on the water surface lensing effect of hyperspectral resolution lidar. It constructs a water surface lensing effect model to characterize the focusing phenomenon of pulse energy, uses ECKV wave spectrum to simulate the dynamic water surface, and tracks the laser pulse penetrating the water body based on the law of light refraction. The degree of pulse energy focusing is statistically analyzed using a two-dimensional histogram. Based on the unique molecular and particle separation characteristics of hyperspectral resolution lidar, the method corrects the overestimated water diffuse attenuation coefficient in shallow water areas due to the water surface lensing effect. This invention provides a new solution for correcting the water diffuse attenuation coefficient in shallow sea areas, contributing to improved water quality monitoring accuracy in shallow water regions.