31 results about "Non linear wave" patented technology

A putter type golf club head having a unique ball striking face configuration to eliminate the dimple effect of grooved putters formed with a series of grooves and intermediate land areas between the grooves extending in a longitudinal direction across the striking face. Each of the grooves is characterized by a plurality of repeating, non-linear wave forms located at the center of the striking face and extending outwardly therefrom.

The invention provides a metal plate micro-defect detection method based on nonlinear Lamb waves. The metal plate micro-defect detection method comprises the following steps of: S1, acquiring a phasevelocity frequency dispersion curve and a group velocity frequency dispersion curve of a metal plate; S2, acquiring an excitation frequency, Lamb waves of a specific mode and an incident angle of theLamb waves of the specific mode as model parameters according to the phase velocity frequency dispersion curve and the group velocity frequency dispersion curve; S3, deriving a relative nonlinear coefficient beta' according to the Lamb waves of the specific mode in the S2, wherein the relative nonlinear coefficient beta' is used for representing the depth of a defect; S4, establishing a nonlinearultrasonic test system according to the model parameters; and S5, testing the metal plate according to the nonlinear ultrasonic test system established in the step S4, judging whether the relative nonlinear coefficient beta' is reliable or not, and if so, representing the defects of the tested metal plate by utilizing the relative nonlinear coefficient beta'. According to the metal plate micro-defect detection method, the relative nonlinear coefficient beta' represents the defects of the tested metal plate, the defects of the metal plate can be effectively represented, and the detection precision is improved.

The invention discloses a nonlinear detection method for high-cycle fatigue damage of a metal sheet. The method is suitable for detection and characterization of fatigue early-stage micro-defects and micro-damages in the metal sheet, and belongs to the field of nondestructive testing. The method comprises the steps: firstly, determining the excitation frequency of a fundamental frequency wave according to a measured object and a nonlinear Lamb wave resonance condition; arranging a pair of detection probes, namely an ultrasonic transmitting probe and an ultrasonic receiving probe, in the same side direction of a test piece, and carrying out nonlinear detection on the metal sheet structure; scanning different positions of the test piece by changing the excitation time delay of an excitation signal, and extracting a fundamental wave amplitude and a second harmonic amplitude; and finally, according to the change rule of the ultrasonic nonlinear coefficient along with the detection position, achieving detection of the fatigue damage of the metal plate and characterization of the damage degree. According to the invention, a band-pass filter at a certain frequency is introduced, and an original high-pass filter is replaced by the band-pass filter, so that the received signal is purer, and meanwhile, the data processing difficulty is greatly reduced.

A putter type golf club head having a unique ball striking face configuration to eliminate the dimple effect of grooved putters formed with a series of grooves and intermediate land areas between the grooves extending in a longitudinal direction across the striking face. Each of the grooves is characterized by a plurality of repeating, non-linear wave forms located at the center of the striking face and extending outwardly therefrom.

The invention discloses a simulation method of a meshless numerical model, computer equipment and a computer readable storage medium. According to the simulation method of the meshless numerical model, the floating body and fluid interaction numerical model of the improved Riemannian solution meshless algorithm is constructed, and compared with a meshless method in the related technology, the influence of strong nonlinear factors such as rolling, breaking and splashing of a water body on a flow field is fully considered; the problems of stress instability, particle pressure field oscillation and low free surface expression precision are solved, the flow field pressure calculation precision is improved, and the effectiveness and precision of high-precision and strong-impact solid-liquid interaction are achieved in the wave making problem. Therefore, the invention can be suitable for simulating scenes where nonlinear waves and floating bodies interact, has a wider application environment, can be applied to the fields of ship and ocean engineering, offshore engineering and the like, and has a higher use value.

The invention belongs to the technical field of wave numerical water tanks, and provides a fluent UDF-based wave generation method for a numerical wave water tank. According to the method, a basic thought of a push plate type wave maker model established by a boundary element method is adopted; a new wave generation function and a new wave elimination algorithm are established, in secondary development of FLUENT software based on a Navier-stokes equation, a dynamic grid technology of FLUENT is adopted for the boundary of a wave generation plate, only speed boundary conditions are established,pressure and speed items are not coupled, and therefore the stability is higher. Similarly, wave damping layers are additionally arranged at the far ends of the wave making plate and the wave numerical water tank, and only speed items are absorbed. In research, a VOF method is applied to track free surface motion of waves. By applying the wave generation method of the wave numerical water tank, the problem of interaction between complex nonlinear waves and structures can be studied.

The invention relates to a terahertz frequency tripler based on an MIM capacitor and multiple pairs of Schottky diode structures. The terahertz frequency tripler is composed of a waveguide-to-suspension line probe, an input low-pass filter, a nonlinear diode pair balance structure, the MIM capacitor, an inductance coil, a suspension line-to-waveguide probe, a T-shaped cavity and the like. The waveguide-to-suspension line probe is used for waveguide conversion connection between an input end signal source and an output end output, the signal source is filtered by a low-pass filter, and the output signal source is coupled to the center of the balance structure through a Schottky diode to generate a nonlinear wave with triple harmonic waves; and the Schottky diode pairs adopt a multi-pair anti-parallel structure, so that even harmonics are suppressed, and the power-resistant high-voltage performance is improved. The bias voltage VDD end of the diode is added with MIM capacitor grounding and inductance, AC signals are shunted, and bias voltage interference is reduced. The cavity for placing the frequency multiplier adopts a T-shaped structure, so that the use of cantilever beams is reduced, and the noise interference is reduced. The frequency tripler structure has the advantages of being good in stability, high in frequency doubling efficiency, low in noise and the like.

The invention discloses a short-term wind speed prediction method and system. The method comprises the steps of obtaining historical wind speed data; Wherein the historical wind speed data comprises first historical wind speed data and second historical wind speed data, and the first historical wind speed data is data before the second historical wind speed data; Optimizing the neural network model through a genetic algorithm; Training the optimized neural network model through the historical wind speed data to obtain a prediction model; Performing variational mode decomposition on the secondhistorical wind speed data to obtain a plurality of second nonlinear fluctuation wind speed characteristic data; And predicting the second nonlinear fluctuation wind speed characteristic data throughthe prediction model to obtain wind speed prediction data. The method or the system can effectively improve the reliability of the wind speed prediction precision.

The invention discloses a nonlinear wave detection method for an underwater gate. The method comprises the following steps of: firstly, determining a relationship between the group velocity of lamb waves and the product of frequency plate thickness through wave velocity calculation; performing coupling optimization to reduce energy of the lamb waves leaking into water and increase energy of the lamb waves in a gate plate; adopting seven transducers to excite waves to reach a focus point at the same time, generating the maximum scattered wave at the focus point, improving the signal-to-noise ratio and obtaining a detection signal; and then extracting integer frequency multiplication components of the excited waves in a frequency spectrum, adding the frequency multiplication components to serve as the damage degree of the focus point, and sequentially changing the focus point to form a damage image of the whole gate. According to the method disclosed by the invention, the linear waves with structural scattering are removed, and the gate is detected by only adopting the nonlinear waves with damage scattering, so that the lamb waves can detect a metal plate with a complicated structure, and detection can be carried out while water retaining of the gate is not influenced; and overall damage visualization of the gate can be realized, and the damage degree of each point is quantitatively represented.

The invention discloses a water quality index multi-step prediction method integrating wavelet decomposition and a deep neural network. The method comprises the following steps: 1) filling missing values of monitoring historical data of original water quality indexes by using a linear interpolation method; (2) carrying out discrete wavelet transform on the data after the missing values are filled up; 3) constructing an encoder based on the bidirectional gating circulation unit, constructing a decoder based on the unidirectional gating circulation unit and the full connection layer, extracting the correlation between the hidden layer state of each step of the decoder and the states of all the hidden layers of the encoder in combination with an attention mechanism, constructing a neural network model in combination with the encoder and the decoder, and taking a plurality of decomposition sequences obtained after wavelet decomposition as input. The method has the advantages that the characteristics of nonlinearity and complex fluctuation of water quality data are fully considered, the noise influence is weakened, the influence degree of historical data in each step is adaptively extracted, the water quality indexes of multiple weeks in the future are predicted in a one-step and end-to-end mode, and the method has practical application value for water resource management and ecological guarantee.

The invention discloses a nonlinear waveform synchronous and asynchronous NOMA system design method, which comprises the following steps: step 1, establishing a synchronous and asynchronous NOMA system model of a nonlinear waveform MSK-type signal to obtain a received signal, the received signal comprising normalized time delay, transmitting power and response length; step 2, sampling the received signal by adopting an oversampling technology to obtain a received signal sampling value and a matrix form thereof; step 3, according to the Shannon theorem, obtaining the index throughput for measuring the performance of the synchronous and asynchronous systems; step 4, establishing an optimal system design problem taking the maximum throughput as a target according to the throughput expression; and step 5, analyzing the normalized time delay, the transmitting power and the relationship between the response length and the throughput. According to the nonlinear waveform synchronous and asynchronous NOMA system design method provided by the invention, the system can reach the maximum throughput by setting the normalized time delay and the transmitting power of the two users, and the optimal design of the system is completed.

The invention belongs to the field of plate wave early-stage damage nondestructive testing, and particularly relates to a damage positioning imaging method and system based on a nonlinear Lamb wave zero-frequency component, and the method specifically comprises the steps: 1, preparing a model to be detected; 2, transmitting a fundamental wave at a signal excitation point of the model, receiving a zero-frequency signal at the damaged position of the model by a signal receiving point, and obtaining a boundary point at the damaged position of the model; 3, signal excitation and signal receiving are carried out at multiple positions on the model, and a boundary dot matrix is obtained; and 4, performing model damage position positioning imaging according to the boundary dot matrix. The boundary of the material damage is determined by utilizing the high reflection characteristic of zero frequency to the early local damage of the material, so that the position of the material damage is positioned and imaged, the positioning method is simple and efficient, the detection of the early local damage can be as simple as the detection of the macroscopic damage (such as local 1cm cracks) of the material by utilizing linear fundamental waves, and the detection accuracy is high. And related bottlenecks of mixed wave and second harmonic technologies are overcome.

An apparatus and method for wavelength conversion of a signal, for example, a dual-polarization signal, is disclosed. The apparatus implements a single-loop counter-propagating wavelength conversion scheme which provides both up-conversion and down-conversion of the signal within the same loop. Nonlinear wavelength conversion devices in the loop provide both up-conversion and down-conversion of the polarization components of the signal within the loop depending on whether the polarization component travels through the nonlinear conversion device in a clockwise or a counter-clockwise direction. The wavelength-converted signal is available to be extracted from the wavelength-conversion loop. An all-optical wavelength-division multiplexing transponder based on the wavelength-conversion scheme is also disclosed.

The present invention relates to a device and a method for pulse modulation of laser pulses of tunable laser sources. The invention relates specifically to an arrangement for spectral and / or temporal laser beam manipulation of tunable lasers using nonlinear wave interaction. By using a variable, lens based beam forming section it is possible to manipulate a laser pulse provided by a tunable laser source (i.e. tunable in pulse energy, temporal pulse length and / or wavelength) or different laser sources (i.e. different with respect to pulse energy, temporal pulse width and / or wavelength) in such a manner, that nonlinear wave interaction can occur in the most efficient way. The beam forming section according to the invention allows for adjusting the waist of the laser beam and the focal position of the laser beam inside a cell comprising a nonlinear medium.

The present invention is directed to a nonlinear controller for nonlinear wave energy converters (WECs). As an example of the invention, a nonlinear dynamic model is developed for a geometrically right-circular cylinder WEC design for the heave-only motion, or a single degree-of-freedom (DOF). The linear stiffness term is replaced by a nonlinear cubic hardening spring term to demonstrate the performance of a nonlinear WEC as compared to an optimized linear WEC. By exploiting the nonlinear physics in the nonlinear controller, equivalent power and energy capture, as well as simplified operational performance is observed for the nonlinear cubic hardening spring controller when compared to an optimized linear controller.

The present invention relates to a method for non-supervised change detection of multi-spectral remote sensing images based on information expansion, comprising the following steps: 1) band spectrum information expansion based on nonlinear wave band generation: respectively performing multi-spectral images of the previous time phase and the next time phase Extend the band spectral information of any two original bands to obtain the newly expanded nonlinear artificial spectral band; 2) Expand the band space information based on multi-scale morphological reconstruction: the original band and the nonlinear artificial spectral band are respectively reconstructed through space After obtaining the feature set of spatially extended bands by operation, the differential operation is performed to obtain the difference band set; 3) Unsupervised multi-class change detection. Compared with the prior art, the invention has the advantages of realizing limited original band expansion and spatial information reconstruction, realizing automation of multi-type changes, non-supervised detection and the like.

The invention discloses a wedge plunger wave making device suitable for making high-order nonlinear waves, the wedge plunger wave making device comprises a servo system, a motion module, a wave absorbing device and a water tank, the servo system is composed of a servo motor, a driver, a controller and a man-machine interaction interface, one side of the servo motor is provided with a transmission device through a fixing support, and the other side of the servo motor is provided with a driving device; the bottom end of the transmission device is in transmission connection with a movement module, mounting grooves are oppositely formed in the two sides of the water tank, water baffles are slidably connected into the mounting grooves in a sleeved mode and located behind the movement module, and a wave absorbing device is installed at the tail end, away from the water baffles, of the water tank. Wedge body movement rules corresponding to different waveforms are embedded into the servo controller, the servo motor is controlled to drive the wedge body to accurately do vertical movement through the driver, and the movement speed and position of the movement module and the torque change of the motor can be clearly displayed on a human-computer interaction interface. The device is used for monitoring the working condition of wave making equipment in real time.

The invention discloses a three-dimensional space-time fluctuation analysis method for tunnel safety assessment, which uses three-dimensional space-time fluctuation analysis to solve the safety factor of the tunnel lining at any position and at any time, that is, input the safety evaluation wave near the site, and solve the tunnel under the action of a strong earthquake The fracture angle and pressure of the surrounding rock can be used to determine the safety factor of the tunnel lining at any position and at any time. The invention solves the safety factor of the tunnel lining by using the nonlinear wave theory and the layered shear analysis method, which can effectively overcome the problem that the quasi-static method in the standard method cannot fully consider the time, frequency and amplitude of the ground motion, and has the advantages of clear physical meaning. The method of the invention is real-time and comprehensive, can obtain a tunnel safety factor closer to the actual one, and can be effectively applied to the design and construction of the tunnel.

The present invention is directed to a nonlinear controller for nonlinear wave energy converters (WECs). As an example of the invention, a nonlinear dynamic model is developed for a geometrically right-circular cylinder WEC design for the heave-only motion, or a single degree-of-freedom (DOF). The linear stiffness term is replaced by a nonlinear cubic hardening spring term to demonstrate the performance of a nonlinear WEC as compared to an optimized linear WEC. By exploiting the nonlinear physics in the nonlinear controller, equivalent power and energy capture, as well as simplified operational performance is observed for the nonlinear cubic hardening spring controller when compared to an optimized linear controller.

A nonlinear Lamb wave mixing method for the measurement of stress distribution in sheet metal. The invention discloses a stress distribution detection method based on nonlinear Lamb wave mixing technology, which is suitable for stress distribution detection and location of stress concentration areas in plate structures, and belongs to the field of non-destructive detection. Steps of the present invention: the method first determines the excitation frequencies of the two fundamental frequency waves according to the measured object and the nonlinear Lamb wave mixing resonance condition; two columns of A0 modal waves are oppositely excited at the left and right ends of the test piece, and between the excitation signals The sum frequency S0 signal is received at a certain position in the interval, and the nonlinear mixing frequency stress detection of the plate structure is carried out; by changing the excitation delay of the excitation signal, the mixing frequency scanning is performed on different positions of the specimen, and the amplitude of the mixing wave is extracted; finally, according to The change law of the sum frequency difference signal amplitude with the mixing position can realize the detection of the stress distribution of the metal plate and the location of the stress concentration area.

The present invention discloses a brain activity analysis method and apparatus, which is based on a nonlinear waveform decomposition technology, wherein the changes of the intrinsic features in brain waves are decomposed and demodulated to extract the modulation signals of the components, including the frequency-modulation signals and the amplitude-modulation signals. The present invention further uses a feature mask to determine whether to proceed further decomposition and demodulation of the extracted modulation signals. If not, the multidimensional changes of the intrinsic features are obtained according to the feature mask. Then, quantitation and identification is performed to obtain the status of brain function. The present invention not only effectively increases the accuracy of the identification but also uses the feature mask to obviously reduce the complexity and the load of computation.

The present disclosure provides a device and method of generating a nonlinear waveform signal dissipating low power and operating at a high speed. The device includes: a digital preprocessing unit configured to quantize an effective input signal to generate a linear data signal and a residual signal that is a difference between the effective input signal and the linear data signal; a nonlinear digital-to-analog conversion circuit (DAC) having a nonlinear relationship between an input and an output and configured to convert the linear data signal into a first analog signal; a linear interpolation DAC configured to convert the residual signal into a second analog signal to enable a generation of a converted analog signal by an addition of the second analog signal to the first analog signal; and an output circuit configured to output the converted analog signal as a nonlinear waveform signal.

The invention discloses a structure and method for weakening the vibration of the operating mechanism by using the axial non-linear propagation of the wave. The axisymmetric connecting piece with an axial zigzag structure made of damping material is used to weaken the action of the operating mechanism of the circuit breaker. The influence of the generated vibration and the propagation of vibration energy; the transmission path of the vibration wave is changed by adding an axisymmetric connector made of damping material with an axial tortuous structure at certain positions on the vibration wave propagation path in the operating mechanism, The vibration wave propagating in it has both axial and radial paths. The zigzag structure further weakens vibration intensity and absorbs vibration energy by increasing the refraction and reflection of vibration waves. Moreover, the combined use of the damping material and the zigzag structure of the axisymmetric connector prolongs the propagation path of the vibration wave, which further enhances the energy consumption of the vibration wave by the damping material.

The invention provides a method for estimating a sea surface scattering coefficient of a space-based high-frequency radar. The method comprises the following steps that a Fourier series of linear andnon-linear sea surface wave heights is constructed, a relation model between linear and non-linear wave height coefficients is further constructed through a perturbation method, and a relation model between a directed sea wave spectrum and a linear wave height coefficients is established; an incident field electric field intensity is constructed, the incident field electric field intensity is combined to construct components of a sea surface near scattering field electric field in an X-axis direction and a Z-axis direction through the perturbation method according to the Fourier series, and avertical polarization field intensity component model of a sea surface far scattering field magnetic field is further constructed; and a time autocorrelation model of a vertical polarization field intensity component of the sea surface far scattering field magnetic field is constructed, and Fourier transform is used to further construct a sea surface scattering coefficient model. Estimation of thesea surface scattering coefficient provides a reliable basis for parameter design of the space-based high-frequency radar for ocean remote sensing, and is also a theoretical basis for inversion workof ocean echo signals of the space-based high-frequency radar.

The invention discloses an optical fiber-space optical communication signal conversion method based on a chip integrated optical path, which realizes direct conversion between an optical fiber communication signal and a free space optical communication signal on the premise of not using a light source and a detector. The two-dimensional layered material covering the surface of the transmission waveguide is irradiated to generate free carriers, the refractive index of the transmission waveguide is changed, and optical fiber communication carrier waves are modulated, so that conversion from a free space optical communication signal to an optical fiber communication signal is realized; and on the other hand, the conversion from the optical fiber communication signal to the free space optical communication signal is realized through the non-linear wavelength conversion in the high non-linear waveguide and the grating coupler output mode. The optical direct connection link of the optical fiber communication network and the free space optical communication network is opened, the method is feasible, the structure is simple, implementation is easy, and a solid foundation is laid for the machine-fixed interconnection all-optical communication network.

The invention discloses a method and device for reducing nonlinear wave hazards in a vertical rising cyclone phenomenon, and the method comprises the steps: building an AB system model equation based on a vertical rising cyclone parameter, and obtaining a first-order respiration sub-solution expression and a second-order respiration sub-solution expression of the AB system model equation; analyzing the first-order respiration sub-solution expression, and generating state transition analysis conditions by means of group velocities among all components in the first-order respiration sub-solution; enabling the first-order respiration sub-solution and the second-order respiration sub-solution to meet state conversion analysis conditions, and constructing a nonlinear converted wave and a nonlinear complex; adding periodic disturbance to a set initial solution of an AB system model equation to obtain a relation between a given disturbance frequency and an initial frequency in the initial solution; and counteracting or exciting the nonlinear converted wave and / or the nonlinear complex based on the relationship and the state conversion analysis condition so as to reduce the nonlinear wave hazards. According to the invention, part of non-linear waves are effectively offset or weakened, so that possible damage is reduced.

An apparatus and method for wavelength conversion of a signal, for example, a dual-polarization signal, is disclosed. The apparatus implements a single-loop counter-propagating wavelength conversion scheme which provides both up-conversion and down-conversion of the signal within the same loop. Nonlinear wavelength conversion devices in the loop provide both up-conversion and down-conversion of the polarization components of the signal within the loop depending on whether the polarization component travels through the nonlinear conversion device in a clockwise or a counter-clockwise direction. The wavelength-converted signal is available to be extracted from the wavelength-conversion loop. An all-optical wavelength-division multiplexing transponder based on the wavelength-conversion scheme is also disclosed.

The invention relates to the technical field of the hydrodynamic experiment and research, particularly to a vertical-multilayer-control-based internal wave making system and a control method thereof, wherein the system and the control method are used for generating a high-precision internal wave in a water tank or a water pool. The system comprises a water tank, a computer control drive system for generating a non-linear wave control signal, a mechanical transmission system, and a vertical wave making plate; and two layers of liquid with different densities are placed in the water tank. According to the invention, two dual-plate vertical wave making machines are controlled to different non-linear vertical speed distribution information are inputted into the d two layers of liquid with different densities, thereby realizing internal wave simulation in the water tank or water pool. The accuracy and precision are high; and requirements of different tests can be met.

The invention discloses a method, a device and equipment for evolving non-linear waves of an incompressible fluid model. The method comprises the following steps: acquiring a non-linear model for describing an incompressible fluid; according to potential function transformation and the nonlinear model describing the incompressible fluid, a bilinear form of the nonlinear model describing the incompressible fluid is constructed, and the bilinear form comprises an auxiliary function; constructing an auxiliary function in a bilinear form of the nonlinear model describing the incompressible fluid; and obtaining a series of non-linear waves of the incompressible fluid model according to the constructed auxiliary function, potential function transformation and a bilinear form. The invention aims to obtain different types of nonlinear wave solutions of a nonlinear model by using an efficient method with small calculation amount, enrich the types of existing nonlinear waves in the field, apply the method to an incompressible fluid model, and visualize the evolution process of the nonlinear waves of the fluid model.