88 results about "Noise attenuation" patented technology

The invention relates to the technical field of aircrafts, and discloses a noise-considered urban low-altitude unmanned aerial vehicle path optimization method, which comprises the steps of urban environment rasterization and environment parameter setting; constructing an unmanned aerial vehicle noise attenuation model; calculating a noise interference critical distance and building sensitivity weight assignment; solving a noise interference grid matrix; a low-altitude unmanned aerial vehicle path planning model; and improving A * algorithm design. According to the method, the urban environment is rasterized, environmental parameters are set, an outdoor noise attenuation model is established by integrating geometric divergence, atmospheric absorption, ground effect and other factors, the propagation law of unmanned aerial vehicle noise in a complex environment is accurately described, the overall noise exposure and the sensitive area noise exposure are remarkably reduced while the flight safety is guaranteed, and the unmanned aerial vehicle noise attenuation performance is improved. The calculation efficiency is improved through the critical distance, path redundancy is avoided, collaborative optimization of noise control and operation efficiency is achieved, and technical support is provided for standardized operation of urban ultra-low-altitude unmanned aerial vehicles.

The invention relates to the technical field of path planning, in particular to a multi-unmanned aerial vehicle low-noise path planning method and system, and the method comprises the steps: carrying out the modeling of a flight environment of an unmanned aerial vehicle; establishing a sound source directivity model of the unmanned aerial vehicle, and evaluating the noise influence of the flight of the unmanned aerial vehicle on the noise sensitive area according to a noise attenuation formula; and performing path planning by using an acoustically-driven artificial potential field algorithm, generating a flight path of the unmanned aerial vehicle by calculating an attraction potential field, a repulsion potential field and an interaction force among the unmanned aerial vehicles, and updating path planning in real time. According to the method, the noise characteristics are converted into a repulsive force mechanism, the noise characteristics are combined with the artificial potential field, the noise evaluation process is simplified, rapid and real-time path planning is achieved, the noise sensitive area can be dynamically avoided in real time during path planning, and the influence on the noise sensitive area is greatly reduced.

The utility model belongs to the technical field of reactors, and particularly relates to an extra-high voltage shunt reactor oil tank composite noise reduction structure which comprises a rubber plate fixedly installed in an oil tank wall, the outer side of the rubber plate is attached to the surface of the inner side wall of the oil tank wall, and a sound absorption hole-free paperboard is fixedly installed on the inner side of the rubber plate. A double-layer composite perforated plate sound absorption mechanism is fixedly installed on the inner side of the sound absorption hole-free paperboard, gaps are reserved among the rubber plate, the sound absorption hole-free paperboard and the double-layer composite perforated plate sound absorption mechanism, and a gap is reserved between two layers of perforated plates of the double-layer composite perforated plate sound absorption mechanism. The double-layer composite perforated plate sound absorption mechanism comprises a first perforated paperboard and a second perforated paperboard. The composite noise attenuation structure composed of the rubber plate and the multiple layers of insulating paper plates is arranged on the inner side wall of the oil tank, vibration waves transmitted from insulating oil are blocked and weakened through material combination of different media, vibration noise can be reduced, and the composite noise attenuation oil tank is an important measure for solving the problem of noise of an electric reactor.

The invention discloses an intelligent design system and method for an aviation airborne porous system complex flow channel shell part, and relates to the technical field of intelligent design, and the system comprises a data obtaining module which is used for obtaining a three-dimensional flow channel shell model, a working condition parameter set and a manufacturing limit; the feature extraction and arrangement band generation module is used for generating a candidate arrangement band; the hole group design and optimization module is used for generating a circumferential shallow cavity communication scheme and hole group arrangement; the acoustic impedance synthesis module is used for constructing equivalent surface complex impedance; the performance index calculation and association module is used for constructing system insertion loss and system additional voltage drop indexes; the multi-target tradeoff and solution verification module is used for obtaining a definite solution; and the design and manufacturing output module is used for taking the determined solution as parameterized computer aided design data and formulating manufacturing key points. According to the method, the arrangement area can be accurately selected in the complex flow channel, the controlled hole group can be constructed, and both noise attenuation and flow loss are considered.

A method that includes determining a level of sound within an acoustic environment captured by a microphone; receiving, from a headset worn by a user, data indicating an audio processing mode in which the headset is operating; determining a level of attenuation of the sound based on the audio processing mode and the level of sound; estimating sound exposure based on at least the level of attenuation and the level of sound; and transmitting the sound exposure to an application program.

The invention discloses a vibration and noise reduction transmission system and rotary excavating power equipment, and relates to the technical field of power transmission, the vibration and noise reduction transmission system comprises a driving device, a driven device and a transmission device, the transmission device is in contact connection with the driving device and the driven device, and the transmission device comprises a pressurizing part and a vibration reduction part; the pressurizing part is a hard part and is used for power transmission, the vibration reduction part is an elastic energy absorption part and is used for generating elastic deformation when the pressurizing part transmits power, and the vibration transmission frequencies of different positions of the vibration reduction part are different. Buffering of collision is achieved through elastic deformation, noise attenuation is achieved from the interior of a sound source, the noise reduction efficiency is improved, vibration energy is transmitted through an elastic structure, fatigue damage to parts is avoided, the force transmission performance and the noise reduction requirement can be considered, the vibration transmission frequencies of different positions of the vibration reduction part are different, the fixed frequency is eliminated and stabilized, and mechanical waves are isolated.

This application discloses a novel noise reduction structure for a pressure cooker, comprising: a noise reduction seat with openings at both the top and bottom, and a noise reduction cover that can be opened and closed and is disposed above the noise reduction seat. The noise reduction seat and the noise reduction cover are fitted together to form a receiving cavity covering the pressure vent cap. The noise reduction cover has a vent hole, and the inner sidewall of the noise reduction cover protrudes towards the receiving cavity corresponding to the position of the vent cap, forming a reflux wall. This embodiment, through the enveloping receiving cavity formed by the noise reduction seat and the noise reduction cover, completely covers the pressure vent cap within a closed space, forming a physical barrier layer to directly weaken noise propagation. Simultaneously, the reflux wall forces steam to swirl downwards, reducing steam velocity and impact energy before it is discharged outwards through the vent hole. This dual effect attenuates high-frequency impact noise by over 40%, and the compact integrated structure avoids the volume defects of traditional screw-on devices.

The invention relates to an acoustic insulation panel (1) based on Helmholtz single-cavity resonators, designed to effectively attenuate low-frequency noise generated by industrial equipment. The panel (1) is formed by a front wall (2) and a rear wall (3), both U-shaped, enclosing a hollow space (4) that acts as a resonator cavity. The shorter sides (2', 3') of these walls are folded inwards, forming channels that function as inlets (5) to the resonator. Furthermore, an acoustic insulation system composed of several of these panels (1) is described, in which the panels are arranged so as to allow both ventilation and noise attenuation. The associated acoustic insulation method consists of facing the resonators to maximize noise absorption at specific frequencies, ensuring a laminar air flow that improves the efficiency of the system without the need for large volumes or additional silencers.

The invention discloses a fetal heart sound small signal processing method, device, equipment and medium, and relates to the technical field of data processing.The fetal heart sound small signal processing method comprises the steps that ultrasonic echo signals, monitored by a fetus-voice meter, of the fetal heart of a fetus in a pregnant woman of 9 weeks to 14 weeks of pregnancy are obtained, the ultrasonic echo signals are converted into electric signals, and to-be-processed electric signal data are obtained; performing data self-correlation processing on the to-be-processed electric signal data according to a preset data self-correlation calculation condition to obtain a self-correlation coefficient; sequentially performing bottom noise attenuation processing, frequency shift processing and envelope calculation processing on the to-be-processed electric signal data to obtain preprocessed electric signal data; and determining a signal amplification factor according to the pre-processed electric signal data and the autocorrelation coefficient, performing data amplification processing on the pre-processed electric signal data based on the signal amplification factor to obtain amplified electric signal data, and then taking the amplified electric signal data as the processed fetal heart sound small signal. And the fetal heart sound can be clearly and accurately played when the device measures the fetus in the small gestational week.

A wearable audio device can include at least one speaker to provide an initial audio output signal; at least one sensor arranged to: sense at least one characteristic of the initial audio output signal, sense noise external to the wearable audio device, and provide at least one sensor signal related to at least one characteristic of the sensed initial audio output signal and at least one characteristic of the sensed noise; at least one input arranged to accept an input related to a desired level of attenuation of the noise; a processor arranged to: receive the at least one sensor signal and the selected desired level of attenuation, select at least one coefficient from a coefficient table based on the at least one sensor signal or the selected desired level of attenuation, and provide an attenuation signal related to the selected at least one coefficient; and at least one filter arranged to receive the attenuation signal from the processor and produce a filtered audio signal based on the attenuation signal, wherein the at least one speaker is configured to provide an attenuated audio output based on the filtered audio signal.

A method that includes determining a level of sound within an acoustic environment captured by a microphone; receiving, from a headset worn by a user, data indicating an audio processing mode in which the headset is operating; determining a level of attenuation of the sound based on the audio processing mode and the level of sound; estimating sound exposure based on at least the level of attenuation and the level of sound; and transmitting the sound exposure to an application program.

The invention belongs to the technical field of house decoration, and particularly relates to a sound insulation wall for house decoration, which comprises a wall body base layer, a sound insulation functional layer is fixedly connected to the surface of one side of the wall body base layer, and the side, deviating from the wall body base layer, of the sound insulation functional layer is covered with a decorative surface layer; the counterweight base is fixedly arranged on the side, away from the sound insulation functional layer, of the bottom of the wall base layer, a butt joint block is fixedly arranged on one side of the counterweight base, an inner cavity is formed in the other side of the counterweight base, and the inner cavity and the butt joint block are located at the same height position and matched with each other; and the butt joint positioning mechanism comprises a threaded rod, a movable block, a clamping arm and a transverse column, and the threaded rod is assembled in the inner cavity through a bearing. According to the invention, full-dimensional dead-corner-free noise reduction is realized, the noise attenuation amplitude can be greatly improved, the construction noise can be controlled within an environmental protection standard limit value, the interference to the surrounding environment is effectively reduced, and the environmental protection compliance of construction is improved.

The table top range hood comprises a machine body and a draught fan, the machine body is provided with a first flow guide cavity, a second flow guide cavity and a third flow guide cavity which are sequentially communicated, the first flow guide cavity, the second flow guide cavity and the third flow guide cavity are arranged in a U shape, and an inlet of the draught fan is communicated with the third flow guide cavity; oil smoke is suitable for sequentially flowing through the first flow guide cavity, the second flow guide cavity and the third flow guide cavity when the fan works. According to the technical scheme, the first flow guide cavity, the second flow guide cavity and the third flow guide cavity are designed to be arranged in a U shape to form the U-shaped flow channel, the U-shaped flow channel is provided with the corner part, the flowing direction of oil smoke needs to be changed for multiple times in the conveying process, the propagation path of noise is also changed, noise attenuation is achieved, and the noise reduction effect is improved. And therefore, the noise of the table top range hood can be reduced.

The utility model discloses an insulation noise reduction structure of an extra-high voltage oil-immersed shunt reactor, which comprises a plurality of layers of insulation partition plates, a cork rubber pad, a non-adhesive laminated wood fastener, a hot-pressed polyester resin plastic laminated board fastener and a lastrum laminated wood bracket, and the two adjacent layers of insulation partition plates are separated by the cork rubber pad. And the insulating partition plate is fixed on the box wall of the extra-high-voltage oil-immersed shunt reactor through the cork rubber pad, the non-adhesive laminated wood fastener, the hot-pressed polyester resin plastic laminated board fastener and the Lushi laminated wood bracket. The insulation noise reduction structure has enough mechanical strength and certain flexibility, integrates the advantages of reliable mechanical structure, reliable insulation, noise absorption and the like, and solves the problems of high ground potential field intensity and low noise attenuation in a high-voltage line end outgoing line area. The low-noise electric reactor has the advantages of being capable of improving the ground insulation strength of the high-voltage line end and absorbing and attenuating noise, and is suitable for the design of low-noise electric reactors with the grade of 750 kV to 1100 kV.

An acoustic panel for an aircraft providing noise attenuation over a wide frequency band by combining two resonators, and acoustic panel manufacturing method. The acoustic panel includes a rear skin, a cellular structure, an intermediate layer including perforations, a cellular structure, a cellular structure and a resistive skin including perforations. The acoustic panel combines quarter-wave resonators with Helmholtz resonators to provide noise attenuation over a wide frequency range.

This invention proposes a design method for a full-band compact hybrid EMI filter circuit based on current feedback. The method includes: constructing an electromagnetic interference test circuit to obtain the common-mode EMI spectrum required for attenuation by the PWM converter, and establishing a high-frequency equivalent circuit for the PWM converter; obtaining the optimal hybrid EMI filter topology based on the high-frequency equivalent models of active and passive EMI filter circuits and the noise attenuation characteristics of the hybrid EMI filter circuit topology; designing the active EMI filter topology and its high-frequency equivalent model based on the noise cancellation principle of the active EMI filter and the common-mode EMI spectrum; designing the active EMI filter topology based on the noise cancellation principle of the active EMI filter and the common-mode EMI spectrum; designing the passive EMI filter structure based on the common-mode EMI noise spectrum after adding the active EMI filter; and designing the hybrid EMI filter circuit based on the hybrid EMI filter topology, the active EMI filter topology, the passive EMI filter structure, and the high-frequency equivalent models of the active and passive EMI filter circuits.

The application relates to a noise analysis method, in particular to a noise reduction analysis method and system based on urban green land form. The method comprises the following steps: obtaining three-dimensional data of a target green land, and determining three-dimensional form data corresponding to the target green land according to the three-dimensional data, wherein the three-dimensional form data corresponding to the target green land comprises spatial geometric form of the target green land and vegetation three-dimensional form data corresponding to the target green land; constructing a sound propagation-vegetation attenuation coupling model based on the three-dimensional form data; the sound propagation-vegetation attenuation coupling model is used for predicting expected noise at a target position according to a noise source and three-dimensional form data of the target green land; and noise at the target position is predicted based on the sound propagation-vegetation attenuation coupling model, so as to realize high-precision noise attenuation result prediction according to the three-dimensional form of the urban green land, and provide reliable data support for maintenance or planning of the target green land.

A personal acoustic device with passive noise blocking or noise attenuation characteristics for use in high noise environments or for acoustic isolation from an external environment allowing for continuous sound blocking without any power or additional infrastructure. Passive systems have limited ways to fail versus active systems such as active noise cancellation with their complexity that can fail unexpectedly or are unavailable when power is absent. The device comprises an outer cup with an inner cup connected by one or more elements for at least one of locating, retaining and limiting motion of the inner cup with respect to the outer cup, wherein the inner cup fits over a user's car.

A tangible, non-transitory, machine-readable media, includes instructions configured to cause a processor to determine a residual associated with input seismic data received from a seismic source. The residual is indicative of a difference between expected input seismic data and the input seismic data, and wherein the input seismic data is configured to be combed with an expanded window such that the expanded window comprises data generated by an earlier seismic source excitation and received before a time of a seismic source excitation that generated an input seismic trace corresponding to the input seismic data. The instructions are also configured to cause the processor to determine a deblended output based at least in part on the residual. In addition, the instructions are configured to cause a processor to update the deblended output based at least in part on a result from performing one or more recovery operations configured to recover coherent signals from non-coherent signals of the deblended output. The coherent signals comprise a matching parameter. Further, the instructions are configured to cause a processor to filter the deblended output to remove a portion of the deblended output that is before the time of the seismic source excitation or before a predicted earliest arrival time of a seismic wave travelling from the seismic source to a receiver, to generate an improved deblended output comprising less noise than the deblended output. Still further, the instructions configured to cause a processor to transmit the filtered deblended output for use in generating a seismic image. The seismic image represents hydrocarbons in a subsurface region of Earth or subsurface drilling hazards.

A multi-function fuel delivery system, a method of providing fuel delivery and a noise-attenuating and fuel injector housing device address a root cause of audible noise in a fuel delivery system by placing a sufficiently sized volume directly at the inlet of pulsed-type hydrogen injectors, thereby eliminating pressure pulsation and audible noise created by pressure pulsations. Combining a noise-attenuating function and a fuel supply rail capable of supplying hydrogen to multiple injectors, with both performed within a single volume, addresses space-related and cost-related challenges as well as other challenges of the fuel delivery system. The multi-function fuel delivery system includes a hydrogen (H2) heat exchanger, an H2 fuel manifold, and an upper fuel rail (UFR) that receives H2 that is noise-attenuated by the H2 fuel manifold and provides the noise-attenuated H2 simultaneously to a plurality of injectors.

The invention relates to the technical field of seismic dispersion surface wave attenuation, in particular to a seismic surface wave attenuation method. The seismic surface wave attenuation method comprises the following steps: firstly, establishing a surface gradient model according to surface elevation information after smoothing processing; secondly, according to the change relation between the earth surface gradient model and the surface wave dispersion, surface wave dispersion characteristics are counted; thirdly, establishing a frequency dispersion surface wave model according to surface wave frequency dispersion characteristics; then, matching the frequency dispersion surface wave model with actual seismic data to obtain surface wave information in the actual seismic data; and finally, separating the surface waves through a subtraction method on the basis of the surface wave information. According to the method, surface waves are effectively attenuated on the premise of ensuring that effective reflection is not lost, and the purpose of high-fidelity noise attenuation is achieved.

A sound attenuated material handling element reduces vibration and sound in a material handling system. The material handling element may be a sound attenuated roller for use in a roller conveyer or a sound attenuated nestable tote for receiving and transporting articles in the material handling system. Reducing vibration in material handling element reduces the noise produced by the element. The sound attenuated roller includes sound attenuating material disposed inside of the roller and in contact with the inner surface of the roller body. The sound attenuated nestable tote includes sound dampening material disposed in or formed with the tote structure. The sound damping material may be integrally formed with the roller or tote in order to maximize vibration and noise attenuation. Three dimensional computer analysis may be used to determine optimized locations for placement of the sound damping material on the roller or tote.

The invention relates to the technical field of polymer composite material synthesis, and discloses a noise-reduction skin material and a preparation method thereof.According to the noise-reduction skin material and the preparation method thereof, the multi-layer structure design of a surface layer, a sound absorption layer and a sound insulation layer is adopted, and the surface layer is subjected to electrolytic oxidation treatment to generate a porous oxidation film, so that sound wave scattering and interface impedance matching are enhanced; the gradient pores are formed in the sound absorption layer, so that wide-frequency-band noise can be effectively absorbed, and the noise reduction efficiency is improved; the sound insulation layer is formed by compounding nanoscale silicon dioxide aerogel and graphene and has the characteristics of high acoustic impedance and low density, the isolation effect of the material on high-frequency noise is further enhanced, and the noise attenuation rate of the material within the frequency range of 50-5000 Hz reaches 30 dB or above.

The invention relates to the field of silencers, and discloses an exhaust silencing system which comprises a first silencer, a second silencer and a third silencer which are sequentially connected in series. The first silencer comprises a first resonant cavity and a first filling cavity which are sequentially arranged in the airflow direction, and the first resonant cavity is configured to attenuate noise of a first target frequency band; the second silencer comprises a second resonant cavity and a second filling cavity, and the second resonant cavity is configured to attenuate noise of a second target frequency band; the third silencer comprises a resistant silencing cavity and a third filling cavity, and the resistant silencing cavity is configured to attenuate noise of a third target frequency band; the first filling cavity, the second filling cavity and the third filling cavity are filled with sound absorption materials, and any two of the first target frequency band, the second target frequency band and the third target frequency band at least comprise different frequency ranges. According to the exhaust and noise elimination system, the exhaust and noise elimination system is connected in series in structure and complementary in acoustic function, and a full-band coverage noise attenuation path with complementary frequency bands is jointly formed.

To implement some methods of attenuating noise it can be useful to obtain an accurate estimate of the noise in the microphone signals. Examples of the disclosure provide a method of accurately estimating incoherent noise levels. In examples of the disclosure a primary estimation of a noise amount is made. The primary estimation of a noise amount is used to determine a direction parameter and a diffuseness parameter. The determined direction parameter and the estimated diffuseness parameter are used to estimate a predicted level difference between a first microphone signal and a second microphone signal. A level difference between the first microphone signal and the second microphone signal is determined and a noise level is estimated using at least the determined level difference and the predicted level difference.

A cooling fan assembly for a nuclear imaging system is provided, wherein the fan assembly may include: a fan; an air inlet opening; an air outlet opening; and a honeycomb structured sheet mounted across the air inlet opening whereby when the fan is in operation and air flows through the air inlet opening, the honeycomb structured sheet promotes laminar flow of air at the air inlet opening and attenuates acoustic noise generated by the fan.

This disclosure relates to the field of petroleum geophysical exploration technology, and particularly to a method, apparatus, device, and medium for strong stacking noise attenuation analysis. The method includes: dividing the original pre-stack seismic data into time windows to obtain target time windows; statistically analyzing the amplitude energy characteristics, velocity characteristics, and frequency characteristics corresponding to the original pre-stack seismic data in each target time window; constructing a dynamic feature matrix based on the amplitude energy characteristics, velocity characteristics, and frequency characteristics; fitting the feature data in the dynamic feature matrix to obtain a stacked noise model; adaptively attenuating the stacked noise model using the original pre-stack seismic data; when the denoised signal does not meet the denoising standard, returning to the step of dividing the original pre-stack seismic data into time windows to obtain target time windows, until the denoised signal meets the denoising standard; and outputting the denoised signal when the denoised signal meets the denoising standard. This invention can improve the accuracy of strong stacking noise attenuation.

The application discloses a wind-fish integration layout optimization method and device considering offshore wind power underwater noise, equipment and storage medium, relates to the seawater culture engineering technical field, and comprises the following steps: based on the linear relationship between wind speed and noise source sound source level and the noise attenuation model with underwater distance, an underwater noise propagation model of a wind turbine generator unit is established; based on the wake effect of the wind turbine generator unit, a power generation calculation model of a wind farm is established; based on a target function with the purpose of maximizing total power generation, a wind turbine generator unit spacing constraint and a noise limit constraint of a culture area, an optimization model is constructed; the wind turbine generator unit coordinates and the culture net cage coordinates are taken as inputs of the optimization model, the optimization model is solved, and the optimized layout positions of the wind turbine generator unit and the culture area are obtained, so that the single economic perspective of only considering power generation efficiency in traditional wind farm planning is broken through, the underwater noise pollution is taken as a core constraint and integrated into the layout optimization, and therefore, the contradiction between marine energy and resources is reduced.

The preparation method of the automobile cotton felt sound insulation pad with the multi-layer composite structure comprises the following steps: step 1, surface layer raw material pretreatment: 35-40 parts of polyester chips, 4-7 parts of nano silicon dioxide and 3-5 parts of a flame retardant are uniformly mixed, and modified polyester staple fibers are prepared through melt spinning, drafting and cutting, the fiber length is 38-51 mm, and the linear density is 1.5-3.0 dtex; the sound insulation and noise reduction effects are remarkable, broadband noise is covered, the middle layer is of a sound absorption cotton and sound insulation film composite structure, glass fiber / basalt fiber sound absorption cotton can efficiently absorb medium-high frequency noise (such as tire noise and wind noise), and the EVA and TPU sound insulation film can block low frequency noise. The polyurethane foaming cotton of the buffer transition layer further weakens sound wave conduction, and full-band noise attenuation is achieved in cooperation with the damping effect of the modified polyester acupuncture cotton on the surface layer.

The invention relates to a noise analysis method, in particular to a noise reduction analysis method and system based on urban green land morphology, and the method comprises the steps: obtaining the three-dimensional data of a target green land, and determining the three-dimensional morphology data corresponding to the target green land according to the three-dimensional data, the three-dimensional shape data corresponding to the target green land comprises a spatial geometric shape of the target green land and vegetation three-dimensional shape data corresponding to the target green land; constructing an acoustic propagation-vegetation attenuation coupling model based on the three-dimensional form data; the sound propagation-vegetation attenuation coupling model is used for predicting expected noise of a target position according to a noise source and the three-dimensional form data of the target green land; and performing noise prediction on the target position based on the sound propagation-vegetation attenuation coupling model, thereby realizing high-precision noise attenuation result prediction according to the three-dimensional form of the urban green land, and providing reliable data support for maintenance or planning of the target green land.