294 results about "Full wave" patented technology

The invention discloses a method and device for measuring a crystal electro-optical coefficient at low voltage, and relates to the technical field of photoelectric coefficient measurement, and the method comprises the steps: employing a wavelength tunable laser as an incident light source of a crystal electro-optical coefficient detection system; before an incident light source is input into a to-be-measured laser crystal, a wave plate is added to serve as a phase compensator to generate phase delay phi 1, and meanwhile the to-be-measured laser crystal generates phase delay phi 2 under the action of direct-current voltage; when the crystal electro-optical coefficient detection system is a half-wave voltage detection system; adjusting the wavelength of the tunable laser so that 3pi / 4 is less than or equal to phi1lt; pi; when the crystal electro-optical coefficient detection system is a full-wave voltage detection system, the wavelength of the tunable laser is adjusted to enable 7pi / 4 to be smaller than or equal to phi1lt; 2pi. As the used light source is the wavelength tunable laser, phi 1 can be adjusted in a large range by changing the wavelength, so that phi 2 and the test voltage are changed, the purpose of measuring the electro-optical coefficient of the crystal at low voltage is achieved, and the test safety is improved.

The invention discloses a superconducting rectifier, a superconducting diode and a manufacturing and control method thereof, and belongs to the technical field of superconducting electronics, the superconducting rectifier comprises more than one superconducting diode, the superconducting diode comprises an insulating substrate and a superconducting nanowire, the superconducting nanowire is provided with a narrowing section, and the narrowing section is provided with a narrow section. The narrowing section is connected with a first gate line and a second gate line, the first gate line and the second gate line are symmetrically arranged, and the first gate line and the second gate line are both perpendicular to the superconducting nanowire. According to the invention, in-situ reconfigurable reversal symmetry destruction can be realized through a nanoscale hot spot controlled by a grid electrode; electrically controlled opening or closing and polarity reversal are realized by adjusting a small grid current without changing a magnetic field; the superconductive rectifier realizes electrically reconfigurable full-wave and half-wave rectification, and paves a way for development of extensible and electrically programmable superconductive electronic devices.

The utility model discloses a balun-integrated full-wave oscillator radiation unit, and aims to solve the problems that a low-frequency bowl-shaped oscillator and a high-frequency die-cast half-wave oscillator are used in the conventional high-low frequency nesting scheme, so that the requirements of miniaturization and light weight of an antenna are difficult to meet, the processing cost is extremely high, and the cost is low. And meanwhile, the high-frequency oscillator is arranged in the bowl-shaped oscillator, so that the horizontal plane wave width deformation of the high-frequency oscillator is caused, the gain is influenced, and the market demand cannot be met. The Balun-integrated full-wave oscillator radiation unit comprises a fixed support and a PCB radiation plate installed on the fixed support. The structure of the full-wave oscillator is relatively simple, assembly can be completed only by installing the single-balun integrated feed sheet in the fixing support and welding and fixing the single-balun integrated feed sheet and the PCB radiation plate, miniaturization design can be achieved through the microstrip technology, the printed circuit technology and the like due to the fact that single-face embedded coupling is adopted, the requirement of miniaturization equipment is met, machining is easy, and cost is low. The production efficiency can be greatly improved, and the production cost is reduced.

A method for performing an elastic full wave inversion (FWI) includes generating an initial P wave velocity model. The method also includes producing a subsurface seismic image or an image gather based upon the initial P wave velocity model. The method also includes estimating elastic properties based upon the subsurface seismic image or the image gather. The method also includes performing elastic full wave inversion (FWI) on the initial P wave velocity model and the elastic properties to produce updated elastic properties.

The invention discloses a method for inverting the velocity of a cementing medium after casing based on ultrasonic Lamb waves, and relates to the field of geophysical logging. According to the method, ultrasonic Lamb wave logging and ultrasonic pulse reflection logging are carried out at all depth points through a post-casing scanning imaging logging instrument, waveform records at all the depth points are obtained, the thickness of a casing in the specified direction at all the depth points and acoustic impedance of a post-casing cementing medium are calculated in an inversion mode, and then the thickness of the casing in the specified direction at all the depth points and the acoustic impedance of the post-casing cementing medium are calculated on the basis of the ultrasonic Lamb wave logging waveform records. For each specified orientation of each depth point, Fourier transform is carried out on the full waveform of the near-bending Lamb wave and the full waveform of the far-bending Lamb wave, the phase difference of the far-bending Lamb wave and the far-bending Lamb wave is calculated, group delay processing is carried out, the working frequency band of the imaging logging instrument is scanned after combination, and the phase difference of the far-bending Lamb wave and the near-bending Lamb wave is calculated; and frequency values corresponding to the minimum values of the group delays at all the directions of all the depth points are obtained, and after a frequency set is obtained, the wave velocity and the medium type of the cementing medium after casing are determined according to the frequency values at all the directions in the frequency set, the frequency number of the minimum values and the acoustic impedance value.

The invention relates to an interconnection line parameter extraction method based on a layered medium Green function improved moment method and a program product, and the method comprises the following steps: setting a sweep frequency parameter and a layered medium structure parameter, constructing a layered medium Green function, and carrying out the calculation to obtain an approximate solution of the layered medium Green function; establishing an electric field integral equation under the layered medium, and performing discretization processing to obtain a corresponding matrix equation; and performing iterative solution on the matrix equation to obtain the overall current distribution of the model, calculating the current value and impedance / admittance value of a port, performing electromagnetic calculation in a frequency sweep mode to obtain different port parameter values, and finally obtaining a parameter-frequency curve to complete the extraction of the port parameters. Compared with the prior art, the stratified medium Green function is fused into the frame of the enhanced electric field integral equation, electromagnetic simulation calculation of the full wave band from 0 frequency to 20 GHz can be achieved, and the method has the advantage of being high in calculation and solving efficiency.

The invention relates to the technical field of switching power supplies, and discloses a gallium nitride charger based on a 494 PWM chip, which comprises a power panel, a rectification circuit module, a half-bridge gallium nitride driving module, a transformer, a 494 chip control module, a totem pole driving module, an isolation driving transformer, a full-wave rectification module, a filter circuit module and a conversion circuit module, the core is that the 494 chip control module generates a PWM signal, and the PWM signal sequentially passes through the totem pole driving module for current amplification and the isolation driving transformer for electrical isolation and signal coupling to drive the two gallium nitride transistors in the half-bridge topology for high-frequency alternate switching. According to the invention, the high-speed switching characteristic of the gallium nitride device is fully exerted, and the charger can work at a higher frequency, thereby reducing the switching loss, reducing the size of a magnetic element, and achieving the high power density and high overall conversion efficiency while improving the power level to a kilowatt level.

To provide a controller in which total harmonic distortion (THD) can be improved.SOLUTION: A controller (700) includes: a first external terminal receiving a first voltage (Vmult) with a full-wave rectified waveform; a second external terminal receiving a first detection voltage (Vis), as a negative voltage, generated by a current flowing through a sense resistor (Ris) connected to a ground potential application terminal; an error amplifier circuit (710) generating a second voltage (V2) by amplifying an error between a second detection voltage (Vs) corresponding to an output voltage (Vdc) and a reference voltage (Vref1); an arithmetic circuit (733) generating a third voltage (V4) by multiplying the first and second voltages; an inverting amplifier (734) generating a fourth voltage (V5) by inverting and amplifying the first detection voltage; and a comparator (735) comparing the third voltage and the fourth voltage.SELECTED DRAWING: Figure 11

The invention discloses a diffracted wave impedance inversion method based on full wave field information, and the method comprises the steps: carrying out the diffracted wave separation of full wave field original seismic data, and obtaining reflected wave seismic data and diffracted wave seismic data; converting an interval velocity body obtained by processing the full-wave-field original seismic data to obtain an interval velocity low-frequency impedance body; determining a corresponding relation between the full-wave-field original seismic data and the synthetic seismic data in-phase axes, and extracting a comprehensive wavelet; under the constraint of the logging data and the interval velocity low-frequency impedance body, based on the comprehensive wavelet, a post-stack impedance inversion method is adopted to perform inversion on the full-wave-field original seismic data, and a full-wave-field absolute impedance body is obtained; under the constraint of a layer velocity low-frequency impedance body, based on the comprehensive wavelet, a post-stack impedance inversion method is adopted to invert the reflected wave seismic data, and a reflected wave relative impedance body is obtained; and removing the reflected wave relative impedance body from the full wave field absolute impedance body to obtain the diffracted wave absolute impedance body. According to the method, the wave impedance inversion precision of the heterogeneous reservoir can be improved.

The invention provides a composite material damage imaging method and system, and belongs to the technical field of material detection.The composite material damage imaging method comprises the steps that original signals are processed through a frequency domain analysis method, and environmental noise in the signal acquisition process is filtered out; establishing a full wave field data energy curve based on the original signal after the environmental noise in the signal acquisition process is filtered out, and analyzing the attenuation characteristic and the global distribution condition of wave field energy; compensating the original signal based on the attenuation characteristic, obtaining a compensation wave field based on the compensated original signal, and selecting a time window of damage imaging based on the global distribution condition of the energy of the compensation wave field; constructing a damage index based on a wave field gradient, and calculating a wave field damage matrix; and calculating a spatial distribution matrix of damage indexes by adopting an MS effective value based on a time window and a wave field damage matrix of damage imaging, and performing image fusion based on the spatial distribution matrix to create a final damage image. According to the method, the influence of strong incident wave components on damage identifiability is inhibited, and accurate identification of multiple damages is realized.

The invention discloses a communication method based on a low-noise high-dynamic full-wave radio frequency channel amplification circuit, and relates to the field of wireless communication and radio frequency integrated circuits. The method comprises the following steps: firstly, sampling a baseband signal and constructing a multi-dimensional time sequence feature vector containing a historical state and a change rate; predicting a signal envelope peak value in a future time window by using a lightweight long short-term memory network (LSTM); a dynamic bias control signal is then generated based on reverse mapping and parasitic parameter compensation. Digital delay is introduced into a radio frequency main path, so that bias voltage is pre-loaded to a grid electrode of an amplifier before a radio frequency signal arrives, and negative delay control is realized; and finally driving the amplifier through asymmetric filtering. According to the invention, the problem of signal truncation distortion caused by response lag in the traditional dynamic bias technology is solved, the amplifier is in a deep AB-class or B-class state of low quiescent current for a long time while ensuring no distortion in a high dynamic range, the power consumption and the thermal noise are greatly reduced, and the signal-to-noise ratio of the system is improved.

The invention discloses a large-aperture super-structure lens and refraction lens mixed optical system design evaluation method, which comprises the following steps: (1) carrying out ray tracing optimization design based on a phase surface of a large-aperture super-structure lens and a refraction lens to obtain a target phase equation of the phase surface of the super-structure lens; (2) establishing a metasurface unit database forming the metasurface lens, and arranging metasurface units to fit a target phase of the large-aperture metasurface lens; (3) evaluating the phase fitting degree and the imaging quality of the optical system by using a large-aperture super-structure lens full-wave simulation substitution method, and evaluating the imaging quality of the optical system by using a ray tracing method; evaluating the image quality indexes of the super-structure lens and the hybrid optical system, and if the image quality indexes meet the technical requirements, completing the design of the folding and super hybrid optical system; and if the technical requirements are not met, returning to the step (1) to carry out design optimization. By using the method provided by the invention, the imaging quality of the super-structure lens in the hybrid system can be effectively evaluated.

The invention discloses an electromagnetic field shaping method based on multi-port excitation-structure cooperation, and belongs to the technical field of electromagnetic wave propagation and electromagnetic device design. According to the method, a unified analysis relation among the multi-port excitation amplitude phase, the variable structure and the target field distribution is established, the limitation that an existing IMPM method is only suitable for single-port-structure field forming is broken through, and collaborative optimization of the structure and multi-port excitation is achieved; according to the method, through the conversion relation between the impedance matrix and the scattering matrix, full-wave simulation is prevented from being repeatedly called in the optimization process, the calculation cost is greatly reduced, and efficient target field construction and optimization are achieved; according to the method, the auxiliary discrete ports are adopted to obtain the field response under the action of the structure, and the linear superposition relation of the field response of the ports is utilized to realize the rapid calculation and reconstruction of the target field distribution, so that the universality and reusability of the method are improved, and the method is suitable for different platforms such as a waveguide device and a free space antenna.

The invention discloses an intelligent design method for a dual-frequency wide-angle high-transmission metasurface, which comprises the following steps of: performing layered sampling on geometric structure parameters of a metasurface unit, performing equal-interval sampling on incident angles, performing full-wave electromagnetic simulation on a parameter sample group to obtain transmission electromagnetic response data, and constructing a database; a multi-layer perceptron neural network is used for learning a nonlinear mapping relation among geometric structure parameters, incident angles, frequencies and transmission coefficient amplitude values, and an independent test sample is used for evaluating the prediction precision and generalization ability of the trained multi-layer perceptron neural network under wide angles and dual frequency bands. A substitution model is constructed based on the trained multi-layer perceptron neural network, the substitution model is embedded into a global optimization process, structural parameters are iteratively optimized in combination with a heuristic search algorithm, an optimal design meeting a dual-band high-transmittance index is obtained, the precision and efficiency of metasurface design are remarkably improved, and the performance of the metasurface design is improved. While the wide-angle double-frequency high transmission performance is ensured, the design period is greatly shortened.

The invention discloses a signal enhancement super-permeable membrane for multi-system and multi-band wireless communication and a preparation method thereof. Relates to the technical field of electromagnetic regulation. The signal enhancement ultra-permeable membrane is composed of a large number of equilateral metal pattern units, a PET film layer and an electric smelting quartz glass dielectric layer. Each metal pattern unit is of an axially symmetric I-shaped metal structure with adjustable length and rotation angle; the transmission phase and amplitude modulation of incident electromagnetic waves can be realized by adjusting the length of the metal wire, the radian of the metal ring and the rotation angle. Full-wave simulation shows that the metal units with different sizes are orderly arranged on the PET film and are deployed on the two sides of the electric smelting quartz glass, so that macroscopic regulation and control of incident electromagnetic waves with different frequency bands can be realized respectively, and the signal gain peak value exceeds 30dB; signal enhancement of multi-band wireless communication can be realized by adjusting structural parameters of the unit structure.

The application discloses a data transmission method, system and equipment of an array receiving acoustic logging instrument, a panoramic acoustic imaging logging instrument adopts a method of underground large data storage and two-way data transmission with a ground system, function implementation is realized by combination of a data acquisition module, a main control module and a data storage module, demodulation of a command sent by the ground system is realized, six acoustic transducer transmission modes are realized, a large amount of data of 96 full wave trains received in each mode is transmitted and stored underground, instrument state data and part of logging data are sent to the ground system, underground large data storage and two-way data transmission with the ground system are realized, and the problem that data cannot be transmitted to the ground system in real time and stored in real time due to limitation of a long cable data transmission rate in actual application is solved.

The invention provides a method for processing and imaging sound wave remote detection data in a well, and belongs to the field of oil-gas exploration. The method comprises the following steps of: firstly, evaluating full wave train data by adopting an energy statistical method, eliminating data with problems, and recovering damaged data by utilizing a POCS interpolation method; then, completing reflection wave extraction based on polarization characteristics of direct waves and reflection waves, and performing optimization through multi-stage filtering processing and amplitude restoration; and then, optimizing a speed extraction method in dynamic correction by using a competition-cooperation particle swarm algorithm, and providing an accurate stacking speed for common sound source gather stacking. And finally, utilizing a frequency-wavenumber domain migration method to realize well-side fracture cavity imaging. According to the method, through an innovative data processing algorithm and flow optimization, imaging of the well-side fracture-cavity body is achieved, and a reliable technical means is provided for oil-gas exploration of a complex reservoir.

The invention discloses a circuit integration device for plasma ignition based on direct current power supply, relates to the field of plasma ignition, and aims to solve the problems that an existing plasma ignition technology cannot be directly compatible with aviation low-voltage direct current and is poor in reliability. A core electronic function module comprises a high-frequency resonance inversion topological unit, an energy driving adjustment topological unit, a full-wave rectification topological unit, a control unit, an arc striking unit and an energy storage unit. The high-frequency resonant inversion topology unit converts input direct current into high-frequency alternating current pulse; the energy driving and adjusting topological unit drives and adjusts the high-frequency resonant inversion topological unit, so that the alternating voltage output by the high-frequency resonant inversion topological unit is increased to 400-430V; the full-wave rectification topological unit converts the alternating current voltage output by the high-frequency resonance inversion topological unit into stable direct current high voltage and supplies power to the control unit, the arc striking unit and the energy storage unit.

The application provides an optical communication device and system, each wavelength range corresponds to a dummy light filling unit, when receiving signal light not working in full wave state (i.e. only part of the wavelength is on wave), since the input port of each dummy light filling unit only corresponds to receiving signal light of a specific wavelength range, only the dummy light filling unit of the on wave wavelength position can receive signal light, and then the remaining dummy light filling units not receiving signal light can send dummy light, thereby realizing automatic filling of dummy light. This dummy light filling method does not need to detect the on wave / off wave wavelength, and can quickly fill the energy of the wavelength position not on wave after part of the wavelength is on wave / off wave, thereby maintaining the stable operation of the wide spectrum transmission system.

The invention discloses a rotor position detection method for multiplexing a synchronous motor body as a rotary transformer, and the method comprises the following core steps: a, independent detection windings (2) are embedded in grooves of a stator (3), the number of detection coils contained in each phase of independent detection winding (2) is equal to 1 / 2n of the number of rotor salient poles (4), and n is a natural number smaller than 10; b, detection coil parameters of all the independent detection windings (2) are completely consistent, the electrical phase difference between the independent detection windings (2) of each phase is equal to 360-degree electrical angle divided by the phase number of the independent detection windings, and the independent detection windings (2) are uniformly distributed on the inner circumference of a stator slot; c, the independent detection windings (2) of all phases are sequentially connected in series end to end and then connected into a carrier signal generated by a carrier generator, and the real-time angle position of the rotor salient pole (4) is calculated through a precise full-wave rectifier, a potential translation circuit and a position conversion module. A solid rotor position sensor is abandoned, a synchronous motor body is reused as a core component of a rotary transformer, and sensorless rotor position detection is achieved; the device adapts to special working conditions such as high temperature, strong electromagnetic interference and full sealing; according to the invention, excitation current interference is eliminated, the detection precision is improved, position closed-loop control in a zero-speed-full-speed range is realized, the response speed is high, the control precision is high, the production cost is low, and the synchronous motor is suitable for various synchronous motors with rotor magnetic resistance anisotropy and circumferential uniform distribution, such as a new energy automobile dragging motor, a linear motor and a household appliance totally-enclosed compressor.

The invention relates to an ultra-wideband frequency selective metasurface prediction method based on a rapid prediction algorithm, and belongs to the technical field of electromagnetic engineering. Comprising the following steps: acquiring a single-layer S parameter; phase-amplitude relation modeling is carried out; and constructing a multi-layer structure and optimizing parameters. According to the prediction method provided by the invention, transmission coefficients of units under different unit parameters and different air layer thicknesses can be quickly calculated as long as S parameters of a single-layer structure are obtained; through the innovative technical means, hundreds of hours and even longer time needed by traditional full-wave simulation are greatly shortened to the level of several minutes, and therefore the time expenditure of the simulation process is remarkably reduced. By means of the improvement, the design iteration efficiency is greatly improved, clear structure adjustment guidance is provided for researchers, and resource waste and time loss caused by dependence on blind trial and error and repeated simulation in the past are avoided.

In an embodiment of the invention, a full-wave rectifier circuit includes an EC resonance circuit including an inductor and a first capacitor in parallel, a first end of which is connected to a power supply voltage VDD; a first transistor and a second transistor, the drains of which are connected to a second end of the EC resonance circuit; a third transistor, the source of which is connected to a source of the first transistor and a first current source, the gate of which is connected to a gate of the second transistor and through a first resistor to a bias signal VBN and through a second capacitor to an input signal VINN, and the drain of which is connected to VDD; and a fourth transistor, the source of which is connected to a source of the second transistor and a second current source, the gate of which is connected to a gate of the first transistor and through a second resistor to the bias signal VBN and through a third capacitor to the input signal VINP, and the drain of which is connected to VDD.

The application discloses an antenna pair with high isolation and low cross polarization level, which comprises a first radiation patch and a second radiation patch arranged as two half-circle ring structures, and the first radiation patch and the second radiation patch are connected through a first branch and a second branch; the first radiation patch and the second radiation patch work in a full-wave mode; the first branch and the second branch are arranged to overlap the resonant frequencies under differential and common mode excitation of two feed ports, and good matching is ensured, so that the isolation of the first radiation patch and the second radiation patch in the band is effectively improved; through the above arrangement, the mode Q value under differential and common mode excitation is close to the same, and the first radiation patch and the second radiation patch can further have high isolation in a wider frequency range. In addition, by introducing a first short pin group and a second short pin group, the polarization current in the x-axis direction can be effectively weakened, and the cross polarization level is reduced.

The invention discloses a three-phase staggered four-switch buck-boost integrated LLC (Logical Link Control) DCDC (Direct Current to Direct Current) isolation converter. The converter comprises a transformer based on magnetic integration design and a primary side circuit and a secondary side circuit which are connected with two sides of the transformer, the primary side circuit comprises a three-phase staggered parallel four-switch boost-buck circuit and a three-phase LLC resonant circuit, and each stage of four-switch boost-buck circuit comprises four switch tubes and a preceding-stage inductor. The front two switch tubes are located between the positive electrode and the negative electrode of the direct-current bus and form a front bridge arm, the rear two switch tubes are located between the middle bus and the negative electrode of the direct-current bus and form a rear bridge arm, and the front-stage inductor is connected between the middle point of the front bridge arm and the middle point of the rear bridge arm. The three ends of the three-phase LLC resonant circuit are correspondingly connected with the midpoints of the three rear axle arms respectively; the resonant capacitors of the LLC circuits are in angular connection, and other circuits of the LLC circuits are in star connection; the secondary side circuit is composed of a three-phase interleaved parallel full-wave rectification circuit. The invention has the advantages of wide input, high efficiency, high power density and high switching frequency.

To prevent occurrence of conduction abnormality resulting from repetition of input and interruption of AC voltage in short time with a simple configuration.SOLUTION: A power supply circuit 6 comprises a full-wave rectification circuit 62, a smoothing circuit 63, a first half-wave rectification circuit 66a, a second half-wave rectification circuit 66b, a third half-wave rectification circuit 66c, a voltage conversion circuit 64 and a control circuit 68. The voltage conversion circuit 64 operates when a voltage level of an AC detection line L3 as an output line of the third half-wave rectification circuit exceeds a first reference level and converts primary voltage as output voltage of the smoothing circuit 63 into DC secondary voltage. The control circuit 68 transmits output voltage of the first half-wave rectification circuit 66a to the AC detection line L3 when the secondary voltage is less than a second reference level based on the voltage level of the AC detection line L3 and stops transmission of the output voltage of the first half-wave rectification circuit 66a to the AC detection line L3 when the secondary voltage is less than the second reference level.SELECTED DRAWING: Figure 2

The invention provides a high-speed railway riding comfort sensitive wavelength identification method, device and equipment. The method comprises the following steps: establishing a dynamic model of a train-rail-bridge space coupling random vibration system; the dynamic response of the train-track-bridge space coupling random vibration system under track irregularity random excitation is solved, and a train body vibration response power spectrum is obtained; dividing the random track irregularity spectrum into a plurality of wavelength components according to upper and lower cut-off wavelengths of different wavelengths; on the basis of the vehicle body vibration response power spectrum, comfort indexes corresponding to all wavelength components are calculated, sensitive wavelengths of full wave bands are recognized, and the riding comfort and the sensitive wavelengths are recognized. The high-speed railway riding comfort sensitive wavelength identification method effectively overcomes the defects of low calculation efficiency and insufficient identification capability in the prior art, and provides a high-speed railway riding comfort sensitive wavelength identification solution with high efficiency, accuracy, mechanism definition and strong engineering practicability.

The present disclosure provides a control device for a power factor correction circuit. The power factor correction circuit is disposed in a power supply device configured to generate a direct current output voltage from an alternating current voltage applied to a pair of power supply terminals. The power factor correction circuit is disposed between a full-wave rectifier circuit configured to generate a full-wave rectified voltage by full-wave rectifying the AC voltage and an output wiring configured to apply the output voltage. The power factor correction circuit includes an inductor inserted between the full-wave rectifier circuit and the output wiring, and a switching element configured to switch between an on state and an off state to control a current flowing through the inductor.

The present application relates to the technical field of magnetic particle flaw detection, and particularly relates to a magnetic yoke for fillet weld, a detection device and a detection method. The present application provides a detection device for fillet weld, which comprises a magnetic yoke, the magnetic yoke comprises a first trapezoidal ring and a second trapezoidal ring, the first trapezoidal ring and the second trapezoidal ring are connected through a cross beam; the first trapezoidal ring and the second trapezoidal ring are provided with openings on the same side and the short sides are arranged on the same side, the straight line distance between the long sides of the first trapezoidal ring and the second trapezoidal ring is less than the straight line distance between the short sides; the openings of the short sides and the long sides of the first trapezoidal ring and the second trapezoidal ring are provided with magnetic poles; the current comprises full-wave rectified current and alternating current, the short sides of the first trapezoidal ring and the second trapezoidal ring are connected with different currents, and the long sides are connected with different currents; two sides of the first trapezoidal ring and the second trapezoidal ring are connected with different currents. The present application aims to solve the technical problem that there is no magnetic yoke and detection device for detecting fillet weld defects in the prior art.

The application discloses a kind of based on MPVL algorithm's finite element fast sweep method and device, belong to electromagnetic full-wave simulation technical field, method includes: according to the port type and / or boundary type of electromagnetic field model, construct finite element boundary value equation and finite element variational equation;The finite element boundary value equation is substituted into finite element variational equation to obtain new finite element variational equation;According to the characteristics of wave number in new finite element variational equation, wave number or square root of wave number is extracted as the frequency-related common factor of each term in new finite element variational equation and is arranged, to obtain arrangement equation;Arrange equation is reconstructed as the matrix equation that can use MPVL algorithm to solve, and based on MPVL algorithm, the matrix equation at given expansion frequency point is solved to obtain electromagnetic field value under different excitation.The application realizes fast sweep, and sweep result has higher accuracy.

The invention relates to a casing wave relative amplitude correction method and system based on well cementation cement density, and the method does not consider the influence of the cement density change on the casing wave amplitude during the actual well cementation quality evaluation, and simulates the full-wave waveform of sound waves received in a well through the methods of real axis integration and the like. The classic elastic wave theory and the slip interface theory are combined, and the method which is high in universality and is used for correcting the wave amplitude of the casing with the actually-measured cement density to the wave amplitude of the casing with the compared cement density is determined; according to the simulation result of the sound field in the well, the correction method has a reliable theoretical basis; the actual stratum and the rock physical model are combined, calculation is convenient and simple, universality is high, and applicability is wide.