19 results about "Diffraction" patented technology

The invention discloses an annular plate-containing concentric cylinder wave diffraction hydrodynamic force evaluation method, an annular plate-containing concentric cylinder comprises an inner cylinder, an outer cylinder and a perforated annular plate arranged between the inner cylinder and the outer cylinder, the method is characterized by comprising the following steps: establishing a cylindrical coordinate system at the intersection point of a still water surface and the center of the cylinder, and the z axis is vertically upward; the drainage basin is divided, the outer area of the outer cylinder is set as the outer area, the annular space area between the inner cylinder and the outer cylinder is set as the inner area, and the inner area comprises the area above the annular plate and the area below the annular plate; setting an opening boundary condition, defining a porous effect parameter of the opening annular plate as sum, and setting a related speed potential boundary condition; deriving an outer domain velocity potential and an inner domain velocity potential, and coupling velocity potential solutions through inner and outer domain boundary conditions; and solving the hydrodynamic load and the free surface elevation according to the velocity potential. The invention provides a wave diffraction hydrodynamic force evaluation method without a plurality of characteristic roots for a concentric cylinder structure containing a single-layer horizontal perforated ring plate. According to the method, the inner domain is further divided into two drainage basins, so that the trouble of a plurality of feature roots is avoided, a brand new feature function is established, and the solving efficiency can be greatly improved.

The invention discloses a conjugate differential interference self-correction method for a large-size plane variable-pitch grating, and belongs to the technical field of optical measurement, and the method comprises the steps: enabling the variable-pitch grating to be in a Littrow auto-collimation state, and measuring the positive and negative first-order diffraction wavefront of the variable-pitch grating through a laser topography interferometer; performing differential operation on the positive and negative first-order diffraction wavefronts; moving the variable-pitch grating by a displacement alpha along the positive direction of the X axis, measuring positive and negative first-order diffraction wavefronts at the moment, and performing differential operation; moving the variable-pitch grating by a displacement alpha along the negative direction of the X axis, measuring positive and negative first-order diffraction wavefronts at the moment, and performing differential operation to obtain a second displacement differential wavefront; and performing interference pseudo-shearing operation by using the initial differential wavefront, the first displacement differential wavefront and the second displacement differential wavefront, and solving a variable pitch parameter by using a least square method. According to the invention, the measurement efficiency and precision of the large-size planar two-dimensional variable-spacing grating are obviously improved.

The present invention provides a method and device for extracting deep-earth non-stationary diffraction fields, relating to the technical field of deep-earth resource exploration. The method comprises the following steps: obtaining seismic shot gather data of deep-earth viscoelastic media; performing a reflection wave continuation non-additive transformation on the seismic shot gather data to obtain shot gather reflection continuation gather data; constructing a sparse regularization-constrained least squares problem for solving the adaptive prediction filter coefficients based on the shot gather reflection continuation gather data, a plane wave destruction filter, and an adaptive prediction filter; solving the least squares problem to obtain the target adaptive prediction filter coefficients; and extracting non-stationary diffraction wave data of deep-earth viscoelastic media based on the target adaptive prediction filter coefficients, the shot gather reflection continuation gather data, and the plane wave destruction filter. This method can effectively preserve the spectral and amplitude characteristics of the diffraction waves of deep-earth viscoelastic media, providing technical support for high-precision imaging of deep oil and gas, hot dry rocks, and other deep-layer structures.

The present application relates to a method for analyzing the surface load of a finite-size structure under the action of a far-field explosion wave, wherein the method comprises: determining shock wave parameters at a location of the finite-size structure based on explosion pressure parameters and environmental parameters, calculating the stagnation load on the surface of the structure and a first decay time history of the reflected overpressure based on the shock wave parameters; calculating the propagation speed of a diffraction wave on the surface of the structure based on the environmental parameters and the first decay time history, calculating the first moment when the diffraction wave reaches the target point and the second moment when the shock wave stagnates based on the speed and position parameters of the target point on the surface of the structure; calculating the second decay time history of the diffraction wave with respect to the reflected load based on the reflected overpressure on the surface of the structure at the first moment, the stagnation load at the second moment, the first moment, and the second moment; and determining the load time history of the target point based on the difference between the first decay time history and the second decay time history.

The present invention provides a diffraction wave separation method and device under non-uniform spatio-temporal sampling, which relates to the technical field of seismic exploration. The method includes: acquiring common-offset seismic data of a target area, where the common-offset seismic data includes wave signals of multiple sampling points, and among them, the position intervals between sampling points of different seismic traces are non-uniform, and / or the time intervals between different sampling points of the same seismic trace are non-uniform; calculating the plane wave slope of each sampling point of the common-offset seismic data by using the finite difference method to obtain plane wave slope data; determining the reflection wave travel time curve of each sampling point according to the plane wave slope data; and separating the diffraction waves of the common-offset seismic data according to the reflection wave travel time curves of each sampling point. The present invention realizes accurate separation of diffraction waves under non-uniform spatio-temporal sampling and improves the accuracy of seismic data analysis.

The invention relates to the technical field of seismic exploration data processing methods, and particularly discloses a velocity analysis method and device using imaging domain diffraction energy envelope, and the method comprises the steps: carrying out the migration imaging of a seismic data volume at a batch displacement velocity, and obtaining a pre-stack migration velocity; performing imaging envelope calculation by using the pre-stack migration velocity; and carrying out interactive speed analysis on a result of the imaging envelope calculation, and selecting a proper pre-stack migration speed. The invention provides an imaging gather envelope calculation method based on image cross-correlation, velocity analysis is carried out according to the focusing degree of diffracted energy at different velocities, technical support is provided for accurate velocity interpretation of an underground geologic body, and the problem that conventional migration velocity analysis depends on a reflected wave field and is not accurate is solved. And the diffracted waves are more sensitive to the reaction of the speed.

The application discloses a bridge site area concealed geological anomaly body exploration method based on a hole-in-fall weight seismic source, a receiving survey line is laid out in a bridge drilling construction survey area, a standard penetration test or a conical dynamic penetration probe ramming rock-soil layer vibration is used as a seismic exploration seismic source in in-situ drilling test, a plurality of three-component seismic detectors are laid out along a bridge longitudinal section or a transverse section axis where the drilling is located and receive the vibration signals, single-shot seismic records are formed by collating, a diffraction wave event horizon generated by a concealed geological anomaly body is identified, a diffraction wave is extracted by using time-frequency conversion and a polarization parameter is solved, a diffraction wave propagation space line is constructed based on a rectangular coordinate, a diffraction wave propagation path nearest point coordinate of a detector pair is determined by using a space straight line projection method, and an inversion result profile is formed by a discrete grid point number statistical heat map, a diffraction wave occurrence position is identified, and the concealed geological anomaly body is explained.

The present invention provides a grating wave output pupil expander and an augmented reality display module, which relates to the technical field of augmented reality display modules. The grating wave output pupil expander includes a waveguide flat plate, the waveguide flat plate includes opposite first and second plate surfaces, an input grating and an output grating are arranged on the first plate surface, and the input grating and the output grating are arranged at intervals; a light reflection structure is further arranged on the waveguide flat plate, the light reflection structure has a reflection layer, the reflection layer is respectively connected to the first plate surface and the second plate surface, and the reflection layer is used for reflecting the diffracted light traveling in the direction of the input grating toward the direction of the output grating. When light propagates in the grating wave output pupil expander, a diffraction phenomenon will occur. Part of the diffracted light will move in the direction of the input grating and gradually move away from the output grating. The light reflection structure can reflect this part of the diffracted light toward the direction of the output grating, so as to be reused again, avoid waste of light energy, and ultimately the light energy received by the human eye retina is more and the brightness is higher.

An X-ray diffraction device and a method for processing signals from the X-ray diffraction device are disclosed that can identify charge-sharing events and photon coincidence events by analyzing the time delay between first and second pulses generated by a first and second detector cell, respectively, and by analyzing the energies of the first and second pulses, respectively.

The present invention relates to the field of special equipment detection. The purpose is to provide a method for correcting the depth of defects in TOFD detection of a longitudinal weld of a cylinder. The method can significantly improve the depth positioning accuracy of defects by correcting the display depth, bringing convenience to subsequent defect repair. The technical scheme is: a method for correcting the depth of defects in TOFD detection of a longitudinal weld of a cylinder, which is carried out according to the following steps: 1) Calculate the process parameters according to the flat plate butt weld, and use two probes arranged at an interval distance to perform TOFD detection on the longitudinal weld of the cylinder according to the process parameters to obtain the propagation time t0 of the straight wave, the propagation time t1 of the diffraction wave of the upper end point of the defect, and the propagation time t2 of the diffraction wave of the lower end point of the defect; 2) Select the process parameters required for defect depth calculation: the center distance between the two probes 2S, the outer radius R of the cylinder, and the inner radius r of the cylinder; 3) Calculate the display depth of the defect; 4) Calculate the correction amount Δh of the defect depth; 5) Defect depth correction.

The invention discloses a design method of a parabolic cylinder mixed curled edge reflecting surface, and relates to the technical field of antenna reflecting surface design. According to the method, a parabolic cylinder with a concave edge projection contour is constructed in a central main reflection area, and a mixed curled edge formed by mixing an elliptic curve and an equivalent parabola through a mixing function is constructed on the peripheral edge of the parabolic cylinder. The method comprises the following steps: calculating equivalent parabolas of different azimuth angles under a cylindrical coordinate system taking the center of a reflecting surface as an original point, establishing a local coordinate system at a connection point, respectively constructing an elliptic curve and an equivalent parabolic equation, and finally generating a mixed hemming curve equation through a mixed function. According to the invention, the continuity of the reflecting surface at the joint of the main area and the curled edge can be obviously improved, the edge diffraction is effectively reduced, the diffracted wave is guided backwards to the back surface of the reflecting surface, the disturbance to a quiet area field is reduced, and the test precision and reliability of a compact range test system are improved.

The present invention discloses a phase retrieval wavefront detection method without support region constraint, which can achieve rapid wavefront reconstruction without prior knowledge of the support region. After arbitrarily diffracting a random estimate value to a defocused plane, the wavefront phase of the defocused plane is repeatedly obtained through iteration on the defocused plane, and finally inverse diffraction is performed back to the wavefront to be measured. The present invention replaces the traditional iteration between the wavefront to be measured and the light intensity measurement plane with direct iterative diffraction calculation on the defocused plane, increases the intensity information, improves the tolerance of the algorithm to a loose support region, and further improves the convergence accuracy of the algorithm.

The invention provides an anti-counterfeiting element, and relates to the technical field of anti-counterfeiting, and the anti-counterfeiting element comprises a base material layer; the anti-fake information layer is arranged on one side of the base material layer, and the anti-fake information layer can emit light after receiving the radio wave signal so as to display anti-fake information; the concave-convex structure is arranged on the anti-counterfeiting information layer, and the concave-convex structure can enable light emitted by the anti-counterfeiting information layer to generate a diffraction phenomenon when the anti-counterfeiting information layer emits light, so that under the condition that the anti-counterfeiting information is observed from different observation angles, the anti-counterfeiting information can present a light-emitting effect of different colors or a light-emitting effect that multiple colors are alternately changed; or a dynamic pattern transformation effect is presented. According to the anti-counterfeiting element provided by the invention, the concave-convex structure is arranged on the anti-counterfeiting information layer, so that when the anti-counterfeiting information layer emits light, the concave-convex structure can enable the light emitted by the anti-counterfeiting information layer to generate a diffraction phenomenon, and a user can obtain light-emitting effects with different colors when observing from different observation angles.

The invention provides a horizontal array passive ranging method and system based on a surface waveguide leakage effect, and the method comprises the steps: converting a time domain signal received by a horizontal array into a frequency domain, and carrying out the beam forming to obtain a spatial spectrum; performing incoherent accumulation on the spatial spectrum on a frequency axis to obtain a broadband spatial spectrum, and extracting an angle position corresponding to a spectrum peak in the broadband spatial spectrum; selecting the minimum angle corresponding to the peak value, and obtaining the azimuth angle of the sound source relative to the horizontal array through a diffraction ray theory correction formula; correcting the angle corresponding to the spectrum peak of the seabed reflection wave in the broadband spatial spectrum through the relation between the spatial angle and the azimuth angle, so as to obtain the arrival angle of the primary seabed reflection signal; and obtaining a distance estimation value of the sound source by using the estimated angle of arrival of the primary seabed reflection signal and a ray geometric formula. According to the method, the problem of distance-azimuth coupling occurring when a horizontal line array is used for sound source positioning is solved, and an accurate estimation value of the sound source distance can be given.

The invention relates to the technical field of space telescopes, and specifically provides a method for eliminating the influence of slit diffraction on wavefront detection and a spliced ​​telescope system. The exit pupil surface phases of in-focus images and out-of-focus images are solved by a GS algorithm, and the solution accuracy of the system exit pupil surface phase is optimized under the premise that the defocus amount is known, and the optimized system exit pupil surface phase is used as an optimal estimated value; then, a target function for solving the system exit pupil surface phase is constructed by a PD algorithm, and the target function is solved by an L-BFGS algorithm, and the optimal estimated value obtained by the GS algorithm is used as an initial value of the target function to calculate the system exit pupil surface phase; and a high-precision exit pupil surface phase solution is achieved by cross-iteration of the GS algorithm and the PD algorithm, and the influence of the slit diffraction on the wavefront detection accuracy of the spliced ​​space telescope is effectively suppressed.

The present disclosure provides a small-scale geological anomalous body detection method and device, and relates to the field of small-scale geological anomalous body detection. The method comprises: acquiring diffracted wave shot-gather data collected in a to-be-processed area and determining target single shot data having a distance to the center point, which is a predetermined distance; calculating a first horizontal distance between each shot point in the target single shot data and the center point and calculating a second horizontal distance between the detection point corresponding to each shot point and the center point; constructing a common-diffraction-point gather based on the first horizontal distances and the second horizontal distances; and processing the common-diffraction-point gather by using a correction algorithm of diffracted wave events to obtain a diffracted wave imaging profile.

This application provides an imaging method, apparatus, and equipment for obstacles in a shield tunneling construction area, relating to the field of geological exploration technology for shield tunneling construction. The method includes: acquiring seismic exploration data of the target shield tunneling construction area; obtaining an initial number of modes based on a configuration, performing geometric mode decomposition on the seismic exploration data to obtain multiple initial mode components; calculating a comprehensive score for each initial mode component; calculating a fitness value corresponding to the initial number of modes based on each initial mode component and its corresponding comprehensive score; adaptively optimizing the initial number of modes within a configured mode search interval based on the fitness value corresponding to the initial number of modes to obtain an optimal number of modes; if the initial number of modes is the optimal number, reconstructing the initial diffraction components to obtain a diffraction wavefield; and performing migration imaging on the diffraction wavefield to obtain the imaging result of obstacles in the target shield tunneling construction area. This application can improve the detection accuracy and stability of obstacles in front of the shield tunneling construction area.