900 results about "Noise elimination" patented technology

The invention relates to a three-dimensional reconstruction method based on a visual odometer and deep learning. The method comprises the following steps: obtaining related parameters of a monocular camera through camera calibration; shooting continuous image frames of the target area under the plurality of camera poses through the monocular camera to obtain image frames of the target area after distortion correction under the plurality of camera poses; estimating relative poses of the camera among different image frames by using a visual odometer according to related parameters of the monocular camera; constructing a cost body of the image frame by using a cost body generation model according to the relative pose of the camera; optimizing the cost body generation model by using the geometric consistency loss and the depth consistency loss, and generating a depth map of the image frame through the optimized cost body generation model; performing noise elimination and hole filling on the depth map of the image frame to obtain an optimized three-dimensional map; according to the method, a stable reconstruction effect can be kept in a complex environment, a low-texture region and a scene with a large visual angle span, and compared with an existing single deep learning reconstruction method, the method has higher robustness and reconstruction precision.

The invention discloses a noise elimination circuit structure, a low noise amplifier, a chip and electronic equipment. The noise elimination circuit structure comprises an input matching network; a common source stage amplification path connected with the first differential output end of the input matching network, comprising a first common source stage differential amplifier, and outputting an amplified first signal inverted from the radio frequency input signal to the ground; the common-gate amplification path is connected with the second differential output end of the input matching network, comprises a first common-gate differential amplifier and outputs an amplified second signal which is opposite to the radio frequency input signal to the ground; and the output end of the common-source amplification path and the output end of the common-gate amplification path are connected in parallel to form the output end of the noise elimination circuit structure. The common-source amplification path and the common-gate amplification path required by the noise elimination structure are realized by using one amplifier path, the utilization rate of the layout area is improved, the compactness of the layout is realized, and the amplifier can be widely applied to the field of communication or radar.

The invention relates to the technical field of water quality monitoring and analysis, in particular to an intelligent Agent collaborative decision-making system oriented to environment monitoring. Comprising the steps that original data including water quality parameters and environment data are collected in real time; performing noise elimination, missing value filling and standardization processing on the collected original data, and outputting preprocessed data; the method comprises the following steps: integrating multi-source data including historical monitoring data, pollution source information and treatment cases, performing vectorization coding on the multi-source data by adopting a BERT model, and constructing a retrieval architecture based on hierarchical indexes and inverted indexes of a hierarchical navigable small world to obtain a dynamic water quality knowledge base; and on the basis of a retrieval enhancement generation technology, associating the preprocessed data with the dynamic water quality knowledge base, predicting a water quality change trend through a time sequence prediction model, and generating an abnormality diagnosis report and a closed-loop treatment scheme. According to the invention, analysis and early warning of water quality are realized through collaborative decision-making of the intelligent Agent.

The invention discloses a building live-action three-dimensional reconstruction system based on point cloud data, and relates to the technical field of building live-action three-dimensional reconstruction, the building live-action three-dimensional reconstruction system comprises a preprocessing module, a multistage adaptive noise filtering module, a semantic and geometric joint reasoning module and a three-dimensional model generation module which are connected in sequence; the preprocessing module is used for receiving original building point cloud data, performing registration and initial space division, and outputting a registered point cloud data set. According to the building live-action three-dimensional reconstruction system based on the point cloud data, by introducing a multi-stage adaptive noise filtering and semantic geometry joint reasoning cooperation mechanism, the contradiction that noise elimination is inaccurate and feature details are easy to lose in a complex building scene in an existing method is effectively solved. The system can intelligently distinguish the real discrete noise from the inherent complex geometric features of the building, and maintains the integrity of the details such as decorative members and curved roofs to the greatest extent while ensuring the denoising effect, thereby achieving the high-fidelity point cloud data preprocessing.

The invention relates to the technical field of fracturing wellhead pressure prediction, and discloses a fracturing wellhead pressure real-time prediction method and system, and the method comprises the following steps: collection processing: collecting multi-field data in a fracturing wellhead fracturing process, and carrying out noise elimination and time-space alignment to obtain a standardized time series data set; parameter identification: based on the standardized time series data set, calculating fracture fractal dimensions, fractional order parameters, temperature-sensitive viscosity and random disturbance intensity in the fracturing process by analyzing fracture fractal features and a multi-field coupling relationship to obtain multi-field parameters; and model construction: constructing a physical model fusing fractional order characteristics and random disturbance based on the multi-field parameters. The method comprises the following steps: acquiring and processing multi-field data to obtain a standardized time series data set, extracting multi-field parameters, constructing a physical model fusing fractional order characteristics and random disturbance based on the multi-field parameters, solving by combining fracture expansion constraint conditions, and carrying out weighted fusion on pressure and residual errors of the physical model.

The invention provides a noise elimination structure, a compressor and an air conditioner, the noise elimination structure comprises a first noise elimination component which is detachably arranged on a mounting base, and at least part of the first noise elimination component is used for defining a first cavity; at least part of the second silencing component is arranged on the first silencing component in a sleeving mode, and a second cavity is formed by the second silencing component and at least part of the outer wall face of the first silencing component; wherein at least part of the first silencing part is provided with a plurality of silencing holes, so that the first cavity and the second cavity are communicated through the silencing holes, the silencing frequency band of the first cavity is different from that of the second cavity, the first cavity is communicated with the air outlet of the mounting base, and the second cavity is communicated with the air outlet of the mounting base. At least part of gas flowing out of the mounting foundation flows to the first cavity, the silencing holes and the second cavity for vibration reduction; the problems that in the prior art, compressor micro-perforation can only reduce noise in the same frequency band, and full-frequency-band noise control from low frequency to high frequency cannot be effectively achieved are solved.

The invention relates to the technical field of aluminum alloy part casting processes, in particular to a multi-parameter collaborative optimization system and method for a new energy aluminum alloy part casting process. According to the technical scheme, the multi-parameter collaborative optimization system for the new energy aluminum alloy part casting process comprises a multivariate heterogeneous data acquisition module, a multi-physics field coupling optimization module, an intelligent execution control module, a virtual-real fusion verification module and a man-machine collaborative decision module; by deploying the melt state monitoring unit, the mold dynamic thermal field sensing unit and the equipment health monitoring unit, all-around and high-precision monitoring of melt, mold and equipment states is realized, and meanwhile, space-time alignment and noise elimination are performed on multi-source data through a Kalman filtering algorithm; and generating a characteristic matrix containing a melt fluidity index, a mold temperature gradient field and an equipment health state, and providing a high-quality data basis for subsequent optimization.

The invention provides a radon gas detection method and device, electronic equipment and a storage medium. The method comprises the following steps: collecting a plurality of first electric signals from electric signals flowing through a comparator according to a preset time interval in a target time range; in response to the received interrupt signal from the comparator, determining a second electric signal corresponding to the occurrence moment of the interrupt signal from the plurality of first electric signals; determining a first noise value according to the plurality of third electric signals; the first range value is compensated according to the first noise value, a second range value is determined, the first range value is used for representing a signal peak range of particles corresponding to radon in a noise elimination state, and the plurality of third electric signals are signals different from the second electric signals in the plurality of first electric signals; determining a fourth electric signal whose signal peak value satisfies a second range value from the second electric signals; and determining the concentration value of the radon gas according to the number of the fourth electric signals. The accuracy of radon gas concentration detection can be improved.

The invention relates to an electrical equipment room environment humidity control method and system based on difference comparison. The method comprises the following steps: acquiring original humidity signal data through a humidity sensing array, and performing noise elimination processing to obtain humidity data; calculating a humidity change rate based on the humidity data, comparing the humidity change rate with a preset threshold value, and evaluating the environmental humidity complexity; establishing an equipment humidity demand evaluation model and generating an equipment humidity demand matrix in combination with the physical position, the humidity demand and the environmental humidity complexity of the electrical equipment; based on the matrix, fusing environment state parameters and equipment operation state parameters, and calculating a target comprehensive humidity value by adopting a dynamic weight distribution method; the deviation between the target comprehensive humidity value and the actual humidity data is calculated through a feedback control algorithm, and a humidity control instruction is generated to drive humidity adjusting equipment to execute operation. According to the method, through multi-dimensional parameter fusion and dynamic weight distribution, the accuracy and adaptability of humidity control in a complex environment are improved.

The invention provides a mitral valve regurgitation severity assessment method based on PCG signals, which comprises the following steps: firstly, synchronously acquiring signals from a heart sound area and an environmental background by adopting a dual-channel audio acquisition technology, eliminating environmental noise and operation interference (such as clothes friction and non-uniform pressing force of a stethoscope) through a self-adaptive noise elimination algorithm, and calculating the severity of the mitral valve regurgitation severity; and carrying out segmentation processing on continuous heart sound signals of the de-noised heart sound by adopting a dynamic time window segmentation strategy to generate short-time heart sound fragments, evaluating the quality of the short-time heart sound fragments in real time by using a model based on a lightweight convolutional neural network, and filtering low-quality fragments. Then, nonlinear features are directly extracted from the short-time heart sound fragments through a deep neural network model based on a clique block, after each effective fragment is subjected to four classifications, classification results of all the fragments are integrated through a majority voting mechanism, and final mitral valve regurgitation severity judgment is generated. The classification robustness is effectively improved through multi-fragment information fusion, and the random error of single-fragment analysis is reduced.

The invention discloses an induction heating path optimization method suitable for a heterogeneous noise elimination structure, and particularly relates to the field of induction heating path optimization of the heterogeneous noise elimination structure, and the method comprises the steps: building a grid coordinate in a target region, collecting the heat conductivity coefficient, the specific heat capacity, the thermal resistance value and the induction coil gap value of each grid node in the grid coordinate, generating a thermal response model; and performing heat conduction calculation on the thermal response model and a preset heating power curve, calculating a temperature rise value of each grid node in a fixed preset heating time, marking the grid nodes of which the temperature rise values reach or exceed a safe temperature threshold and the adjacent grid nodes as heat concentration areas, and generating risk area data after gathering the heat concentration areas. A risk assessment and dynamic reordering mechanism based on local thermal characteristic difference is introduced in a heating path planning process, so that advanced identification and real-time avoidance of a heat concentration area are realized.

The present application relates to pipeline system damping and noise reduction technical field, provide a kind of active noise cancellation pressure relief valve, comprising: valve body, with the liquid inlet cavity and pressure relief cavity being communicated are formed;Bypass pipe, with liquid inlet cavity is communicated;Piezoelectric actuator and pressure relief component, pressure relief component includes adjusting piece, pressure relief elastic piece and pressure relief valve core, pressure relief valve core and pressure relief elastic piece are set in pressure relief cavity, adjusting piece is movably arranged on valve body, piezoelectric actuator is arranged on adjusting piece, pressure relief elastic piece is pressed between piezoelectric actuator and pressure relief valve core;Piezoelectric actuator is configured to drive pressure relief elastic piece, to eliminate the transient noise caused by pulsating pressure when pressure relief valve core moves.The active noise cancellation pressure relief valve provided by the present application introduces active noise cancellation technology into the active noise cancellation pressure relief valve pulsating noise control by arranging piezoelectric actuator, can be adjusted by pressure relief elastic piece The force exerted on the pressure relief valve core can eliminate the transient noise caused by pulsating pressure when the pressure relief valve core moves.

The invention provides a control method and a control system for building an independent acoustic space of an automobile cabin, which are applied to the technical field of sound field control of the automobile cabin, and are used for inputting a multi-channel vibration signal acquired in real time into a deep learning noise prediction model to obtain an in-automobile background noise prediction value at a future moment; the prediction noise is filtered by the secondary path estimation model and then is used as a feedforward reference signal for active noise reduction, and the prediction noise and a residual signal collected by a bright area error microphone are jointly used for weight updating of an adaptive filter; the updated filter generates a reverse-phase noise elimination signal and the reverse-phase noise elimination signal is played by a secondary loudspeaker in real time so as to counteract background noise of the bright area; and closed-loop adjustment of the noise reduction effect is formed based on the sound pressure level contrast ratio of the bright and dark areas, so that the independent acoustic space is kept stable in the time-varying environment of vehicle driving. According to the method, the low noise of the bright area and the isolated sound field of the dark area in the vehicle are realized by fusing deep learning noise prediction and active noise control, and the personalized auditory experience in the vehicle can be remarkably improved.

The invention relates to the technical field of exhaust and noise elimination, and discloses a wind power cabin exhaust silencer which comprises an exhaust pipe and a noise elimination pipe which are communicated with each other, an exhaust fan for driving gas to move towards the noise elimination pipe is arranged in the exhaust pipe, and multiple sets of sound absorption assemblies rotating synchronously are arranged in the noise elimination pipe. A gap for air to flow is formed between every two adjacent sound absorption assemblies, and an acute included angle is formed between the plane of each sound absorption assembly and the airflow direction; the sound absorption assembly comprises a first rotating frame and a second rotating frame which are sequentially arranged in the airflow direction and hinged to each other, and sound absorption plates are arranged on the side faces, making contact with airflow, of the first rotating frame and the second rotating frame. According to the silencer, by arranging the included angle adjusting assembly, the included angle between the first rotating frame and the second rotating frame in the silencing pipe is dynamically adjusted, linkage control is conducted on the included angle and the rotating speed of the exhaust fan, and the silencing performance of the silencer can be adaptively optimized according to the actual thermal load of a wind power cabin.

The invention relates to the technical field of pipeline noise elimination, in particular to a pipeline elbow noise reduction device which comprises a connecting elbow, an inner silencer is embedded in a bend of an inner cavity of the connecting elbow, a cavity exists between the inner silencer and the inner wall of the connecting elbow, and a neck bush is arranged between the inner silencer and the inner cavity of the connecting elbow. The inner silencer comprises an inflow part, an inward shrinkage part, a flow guide part and a discharge part which are integrally formed through flexible rubber, the inner diameters of the inflow part, the inward shrinkage part, the flow guide part and the discharge part are smoothly and gradually changed in the flow direction, and the outer wall of the inner silencer and the inner wall of the neck bush are seamlessly attached together. The silencer has the beneficial effects that the gradual change section design of the inner silencer maintains a laminar flow boundary layer through continuous curvature change, and flow separation is effectively reduced; the spiral flow guide fins are used for disassembling macroscopic vortex into micro-scale turbulent flow, so that energy dissipation is accelerated, and medium-high frequency noise is improved in a targeted manner; the sound absorption part is filled with an efficient sound absorption material, and a complementary silencing mechanism is formed with flow field optimization.

The invention provides a high-precision low-delay successive approximation analog-to-digital converter based on sampling noise elimination, and the analog-to-digital converter comprises a main capacitor group which generates an original combined signal according to an original sampling signal and primary sampling noise in a secondary sampling stage; the pre-quantization capacitor bank is used for driving a bottom plate switch of the pre-quantization capacitor bank according to the detection control signal, switching a capacitor weight through a weight control signal to execute pre-quantization operation on the original combined signal and outputting a swing suppression signal; the novel sampling noise elimination module is used for receiving the swing suppression signal, performing gain amplification, generating a purification amplification signal, detecting the differential swing of the original combined signal in real time, and generating a detection control signal and a pre-quantization code according to the differential swing; the successive approximation quantization module is used for generating a main quantization code and a weight control signal according to the purification and amplification signal in a quantization stage; and the digital processing module is used for fusing the pre-quantized code and the main quantized code to obtain a final digital code. And the energy efficiency and the conversion precision of analog signal conversion are obviously improved.

The invention discloses a landslide disaster early warning method based on an LSTM-SARIMA mixed data driving model. Global and local noise elimination is performed on radar displacement monitoring data by adopting a two-stage noise reduction method combining moving average and wavelet transform, so that the signal-to-noise ratio is effectively improved; the method comprises the following steps: decomposing slope displacement data into a trend term dominated by gravity and a periodic term influenced by the environment by utilizing a Hodry-Precott (HP) filtering method, and realizing differentiated analysis of a multi-factor action mechanism; a mixed prediction model combining a long short-term memory network (LSTM) and a seasonal autoregressive integrated moving average model (SARIMA) is provided, modeling and prediction are carried out on decomposed displacement components respectively, and results are fused to obtain a high-precision total displacement prediction value; an improved T-t curve is constructed based on a predicted displacement-time curve, a tangent angle index for landslide early warning is proposed according to a Saito three-stage theory, and quantitative and interpretable early warning criterion setting is realized.

The invention discloses a design method of an array type silencer adaptive to a main ventilation air path between a stator iron core of a hydraulic generator and an air cooler and the array type silencer, and relates to the technical field of suppression or reduction of noise of the hydraulic generator. The method comprises the steps of S1, obtaining aerodynamic noise data and airflow parameters of a main ventilation air path, S2, determining a silencing thought and a micro-perforated plate array core structure according to broadband vortex, discrete rotation, vortex falling and surge noise, S3, determining the boundary dimension and preliminarily calculating the airflow parameters, S4, designing plate parameters in combination with a micro-perforated resonance formula, and S5, calculating the noise of the micro-perforated plate array. S5, performing simulation optimization and S6, accurately accounting airflow parameters, and locking a scheme meeting requirements; the silencer comprises a shell and a plurality of micro-perforated plates, and the multiple layers of micro-perforated plates are arranged in series. The invention has the advantages of no sound absorption material, low wind resistance (the air volume attenuation is less than or equal to 5%, and the pressure loss is less than or equal to 200Pa), the noise of the main wind path is reduced by 5-7dB (A), the service life is long, the operation and maintenance cost is low, and the requirements of the main wind path are met.

The invention is suitable for the technical field of large-scale double-drive mill slipper bearing life prediction, and particularly relates to a large-scale double-drive mill slipper bearing life prediction method based on an adaptive enhanced VMD-BILSTM model, and the method comprises the steps: obtaining an original vibration signal, carrying out the noise reduction processing of the original vibration signal, and obtaining a preprocessing vibration signal; constructing an adaptive enhanced VMD-BILSTM model, extracting degradation features from two dimensions of a time domain and a frequency domain, compressing feature dimensions, and establishing a degradation feature matrix as the input of the adaptive enhanced VMD-BILSTM model; and adaptively determining optimal parameters of the adaptive enhanced VMD-BILSTM model by using a Bayesian network to obtain a residual service life prediction model of the sliding shoe bearing of the large-scale double-drive mill, and predicting the service life of the bearing by using the residual service life prediction model of the sliding shoe bearing of the large-scale double-drive mill. According to the method, WOA-VMD filtering processing is carried out on the original vibration signals, the influence of noise interference in the signals is reduced, the feasibility of noise elimination is proved, and the problem that [K,] parameters are difficult to select is solved.

A sound attenuation system that includes a pliable stem for an earpiece and an earpiece incorporating the stem. The stem includes a curved sound-attenuating distal flange and an attachment portion configured to receive and retain a visco-elastic foam sound-attenuating element in a spaced-apart relation to the curved sound-attenuating distal flange, and a handle portion. The sound-attenuating stem and the foam sound-attenuating element together are configured to fit into the user's ear with improved comfort and flexibility. Some embodiments include a sound-conducting stem channel extending lengthwise through the stem. Some embodiments further include a sound filter configured to insert into the sound-conducting channel in the handle portion, the sound filter including lengthwise filter channel open to the stem channel, and a cover selectably movable to occlude the filter channel or to open the filter channel to external sounds and air pressure.

The invention relates to a multi-channel acoustic black hole sound absorption structure and a silencing device, belongs to the technical field of noise control, and solves the defects of a current acoustic black hole sound absorption structure. The multi-channel acoustic black hole sound absorption structure comprises a shell, one side of the shell is open, and the open side of the shell is used for receiving incident sound waves; partition plates are arranged in the shell to divide the space in the shell into a plurality of sound absorption channels, a plurality of rib plates are arranged in each sound absorption channel, the outer ends of the rib plates are fixed to the inner side face of the shell, the rib plates are arranged perpendicular to the incidence direction of sound waves, the rib plates are arranged at intervals in the incidence direction of the sound waves, and the rib plates are arranged at intervals in the incidence direction of the sound waves. The widths of the multiple rib plates are gradually increased, the inner ends of the multiple rib plates are distributed in a set power law function mode, the inner ends of the multiple rib plates are attached to the outer side face of the perforated plate and fixedly connected with the perforated plate, and the sound absorption structure can better achieve ultra-wideband sound absorption.

The invention discloses a ship dynamic high-precision positioning and abnormal behavior recognition method, and particularly relates to the technical field of navigation positioning. The method comprises the following steps: performing time sequence synchronization and noise elimination on satellite signal propagation time ranging data, carrier phase data and ship attitude data received by a ship; outputting a reflection path coupling relation parameter by analyzing a time-varying coupling relation between the rolling and pitching states of the ship body and a sea surface specular reflection path; by establishing a multi-path deviation correction model, error correction values of satellite signal propagation time ranging data and carrier phase data are calculated; ship track motion state data are output by extracting ship space attitude change features and track geometric morphology features; and updating the ship trajectory motion state data by using the corrected satellite signal propagation time ranging data and carrier phase data to obtain ship positioning trajectory data, and outputting a ship abnormal behavior identification result. And the detection accuracy and reliability of the abnormal behaviors of the ship are improved.

The present invention discloses a rail transit sound barrier based on phononic crystal cells, which is divided into several cells of equal volume by dividing modules; a resonance cavity with an opening on one side is embedded in each cell; one side of the opening of the resonance cavity faces the sound source; the opening extends outward in a trumpet shape to increase the sound receiving area; several phononic crystal cells that do not contact each other are fixedly arranged in the resonance cavity; the resonance cavity in the present invention can achieve triple acoustic performance improvements, namely sound insulation, sound elimination and sound absorption: its overall appearance belongs to a Holmhelix resonance cavity, which is itself a good sound elimination device, which is the first sound elimination; the trumpet-like opening structure on the sound source side is conducive to the introduction of sound waves, and the phononic crystal cells are arranged inside, which is the second sound insulation of the device; the tail adopts a boss with the same size as the end of the trumpet mouth, which is conducive to the flow of sound waves, and a certain thickness of sound-absorbing rock wool is used on the inner wall of the tail, which is the third sound absorption.

The invention provides an ultrathin broadband sound absorption composite structure which comprises a plurality of silencing units, every two of the silencing units are in contact with each other on the same plane to form the three-dimensional ultrathin broadband sound absorption composite structure, each silencing unit comprises a shell, a through hole is formed in each shell, and the through holes are communicated with the silencing units. A thin film is arranged in the position, located in the center of the three-dimensional ultra-thin broadband sound absorption composite structure, of the shell, a micro-pore plate is arranged in the position, located on the periphery of the three-dimensional ultra-thin broadband sound absorption composite structure, of the shell, and the micro-pore plate or the thin film or other resonance structures are arranged in the micro-pore plate or the thin film or other resonance structures in the micro-pore plate or the thin film or other resonance structures. The ultra-thin broadband sound absorption composite structure provided with the micropore plate and the thin film is small in size, the thickness of the ultra-thin broadband sound absorption composite structure is 1 / 23 of the sub-wavelength size, the ultra-thin broadband sound absorption composite structure has the ultra-thin characteristic, the sound absorption frequency band is wide, the noise reduction effect is good, and the ultra-thin broadband sound absorption composite structure can be suitable for sound absorption and noise reduction of various small places and spaces.

The invention provides a screw compressor and a refrigerating system with the screw compressor. A second noise elimination reaction cavity is formed in the position, close to a first noise elimination reaction cavity, of an economizer pipeline for connecting the economizer and the compressor. Pressure pulsation in the economizer pipeline is mainly generated by large pressure difference between refrigerant gas in the compression containing cavity and refrigerant gas in the economizer pipeline, and the distance between the second noise elimination reaction cavity and the first noise elimination reaction cavity is controlled. Different sizes of the silencer reaction cavities are designed according to the operation condition of the compressor, so that the pressure pulsation transmitted from the compression cavity of the compressor can realize good pressure pulsation attenuation within the first-order and second-order target frequency range of the concerned rotating speed after passing through the first silencing reaction cavity and the second silencing reaction cavity; the effective pulsation attenuation frequency range is widened to a great extent so as to adapt to pressure pulsation generated by the compressor under different frequency working conditions.

The invention discloses an aeroacoustic wind tunnel corner noise elimination flow deflector, a flow deflector group and a design method, and belongs to the technical field of aeroacoustic wind tunnel test equipment. The corner flow deflector aims at solving the technical problems that an existing corner flow deflector cannot give consideration to aerodynamic performance and noise elimination performance, and a special shape design method and a combination application scheme are lacked. The noise elimination flow deflector is of an integrated structure formed by sequentially connecting a semi-oval front edge, a front straight section, an arc section, a rear straight section and a wedge-shaped tail edge, and key parameters of the upper profile and the lower profile are designed in an associated mode. The flow deflector set is formed by combining and installing at least two noise elimination flow deflectors according to a specific rule, and a uniform-section airflow channel is formed. According to the design method, coupling optimization of the noise elimination amount and the aerodynamic performance is achieved through a parameterized design process in combination with the Picrov formula, and the design method has the advantages of being high in noise elimination efficiency, small in aerodynamic loss and good in airflow uniformity, is suitable for a symmetric corner aerodynamic acoustic wind tunnel and can be widely applied to aerodynamic noise tests in the fields of aviation, automobiles and the like.

The invention discloses a strong premixing combustion chamber for restraining combustion noise based on a Helmholtz resonant cavity, and relates to the technical field of energy and power. Air and fuel enter the mixing cavity through corresponding connectors to be strongly premixed, premixed gas enters the hearth to be combusted through slit channels among water cooling channel branch pipes, a water cooling channel array can prevent backfire, the Helmholtz resonant cavity is connected with the hearth through a cavity neck and is provided with an air film cooling channel, the size of the Helmholtz resonant cavity needs to measure combustion noise, and a frequency spectrum is analyzed to obtain characteristic frequency. The neck length, the cross section area and the resonant cavity volume are calculated according to a Helmholtz resonance formula, and the sound absorption effect is verified in combination with a low-order thermoacoustic model. Combustion efficiency is improved through the strong premixing and slit water cooling design, tempering is prevented, NOx is reduced, the diffusion combustion problem is solved, the targeted design resonant cavity is matched with air film cooling, the defects that an existing silencing structure is large in size, poor in adaptation and low in high-temperature reliability are overcome, complex active control is not needed, cost is low, applicability is high, and the application range is wide. And cooperative control of high efficiency, low emission and unstable combustion is realized.

The invention relates to the technical field of optical fiber sensing signal processing, in particular to a DAS signal floor noise elimination method, system and equipment based on statistical analysis, and the method comprises the steps: initializing system parameters, and loading a DAS application field data matrix; performing slicing and frequency domain transformation on the DAS original data; dynamically determining a peak threshold value, and performing adaptive peak searching according to the peak threshold value; sorting the identified and screened local maximum values in a descending order, and selecting frequencies corresponding to the local maximum values as main frequency candidates; performing clustering analysis on the selected dominant frequency candidates; calculating the cumulative proportion of each main frequency in the total statistics, selecting a center frequency, and forming the multi-frequency band elimination of the monitoring unit by using band elimination frequency bands formed by different center frequencies; and adding the multi-frequency band elimination to a statistical filtering frequency band set of all the point locations, storing the statistical filtering frequency band set of all the point locations as a statistical model, and performing background noise elimination on the DAS original signal based on the statistical model.

The invention discloses a muffling device, an air conditioner and a muffling control method.The muffling device comprises a shell, an acoustic metamaterial structure and a sound conduction interface, the acoustic metamaterial structure is arranged in a muffling cavity of the shell and is constructed to be a continuous swirling flow channel capable of prolonging a sound wave propagation path in the muffling cavity, and the sound conduction interface is arranged in the shell; the sound conduction interface is arranged at the joint of the shell and the valve pipe. Noise firstly enters the shell through the sound conduction interface, so that sound wave reflection loss is avoided; in the silencing cavity, the continuous swirling flow channel of the acoustic metamaterial structure forces the propagation path of sound waves to be greatly prolonged in a limited space, so that low-frequency resonance noise is effectively inhibited; meanwhile, a physical closed environment provided by the shell isolates external aging factors, and the problems that a traditional rubber damping material loses efficacy due to hardening and the performance of sound insulation cotton is degraded are solved; according to the invention, the risk of new resonance caused by frequency deviation is fundamentally avoided, and synchronous control and long-term reliable noise elimination of low-frequency noise are realized.

The invention discloses an impedance combined type noise elimination structure parameter design method, which comprises the following steps of: firstly, determining target noise reduction quantity and target sound absorption center frequency of a resistive noise elimination section and a resonant cavity resistance noise elimination section according to noise source characteristics, and then iteratively adjusting structural parameters of the resistive noise elimination section and parameters of the resonant cavity resistance noise elimination section; and until the deviation between the sound absorption center frequency of the resonant cavity and the target sound absorption center frequency is within an allowable range, and the noise reduction amounts of the resistive noise elimination section and the resonant cavity resistant noise elimination section respectively reach the corresponding target noise reduction amounts. According to the method, parameters of the impedance combined type silencing structure can be effectively, rapidly and reasonably determined, and the problem that an existing impedance combined type silencer lacks a systematic method for coordinating multi-target constraints such as silencing performance, airflow resistance and structural strength is effectively solved.