34 results about "Acoustical resistance" patented technology

The invention relates to the technical field of railway vehicles, and provides a sound absorption device and a railway vehicle. In the sound absorption device, a surrounding plate structure and a flexible film in sealed connection form a closed cavity, at least one through hole is formed in the flexible film, hollow pipes and the through holes are arranged in a one-to-one correspondence mode, one ends of the hollow pipes are inserted into the corresponding through holes, and the other ends of the hollow pipes penetrate through a sound absorption structure and extend to an interval space between the sound absorption structure and a cavity bottom. And a coupling resonance sound absorption system of the flexible film, the hollow pipe, the interval space and the closed cavity is formed. According to the sound absorption device, the sound resistance and the sound quality are improved through the hollow pipe, the resonance frequency is made to move to the low frequency in cooperation with dual coupling resonance of the flexible film and the hollow pipe and dual coupling resonance of the hollow pipe and the cavity, and low-and-medium-frequency noise of 100-500 Hz is efficiently absorbed; the two types of coupling resonance cooperate to broaden the sound absorption frequency band, and the sound absorption structure is attached to the flexible film to enhance the sound energy dissipation efficiency. Efficient low-frequency sound absorption can be achieved without increasing the size, the requirements for light weight and thinness of railway vehicles are met, and the noise control effect is improved.

The subject matter of the invention is an acoustic absorption structure comprising a unit structure interposed between an acoustic resistive layer and a reflective layer, the unit structure comprising walls delimiting cells, and for at least one cell, the unit structure comprising: at least one and at most three L-shaped partitions, the at least one and at most three L-shaped partitions are impermeable and spaced apart from each other, and define a straight compartment and at least one L-shaped compartment; and an angled, acoustically resistive porous separator in each L-shaped compartment, the angled, acoustically resistive porous separator having a perforation rate of less than or equal to 15%, and dividing the L-shaped compartment into a first region and a second region, thereby forming two types of resonators. This arrangement makes it possible to increase the frequency range of the processed acoustic waves. Another subject of the invention is an aircraft comprising at least one such sound absorbing structure.

The utility model relates to the technical field of electronic microphones, and discloses a vibration-proof noise-reduction silicon microphone, which comprises a metal shell, the inner wall of the metal shell is fixedly connected with a mounting seat, the inner wall of the mounting seat is provided with a noise-reduction sound-transmission assembly, the inner wall of the metal shell is fixedly connected with an elastic steel sheet, and the elastic steel sheet is provided with a vibration-reduction sound-transmission assembly. The inner wall of the elastic steel sheet is fixedly connected with four silica gel supports in a circumferential array, and a substrate is arranged in the metal shell. According to the silicon microphone capable of preventing vibration and reducing noise, noise interference can be effectively reduced and the definition and the purity of audio acquisition can be improved through the arrangement of the noise reduction sound transmission assembly and the acoustic resistance matching film, and then low-frequency vibration can be absorbed and the transmission efficiency of mechanical energy can be reduced through the action of the silica gel bracket and the micro spring; under the action of the silica gel shock pad, high-frequency shock can be reduced, and meanwhile, the elastic steel sheet can provide buffering of low-and-medium-frequency shock, so that multi-stage shock absorption can be formed, the audio quality can be remarkably improved, and the device can keep stable performance output in various environments.

This invention discloses a porous Helmholtz resonator with adaptively adjustable sound absorption frequency band, belonging to the fields of noise control and virtual reality technology. It comprises a sound-absorbing structure consisting of a rotating perforated panel, a fixed perforated panel, and a perforated porous material plate arranged sequentially from top to bottom, as well as an adaptive adjustment system composed of a sound pressure sensor, a controller, and a motor. The motor drives the rotating perforated panel to rotate via gear transmission, changing the perforation overlap area; the perforated porous material plate compensates for acoustic impedance, maintaining sound absorption performance. The controller pre-stores spectral data at different rotation angles and selects the optimal rotation angle by comparing the real-time noise spectrum with the pre-stored data. This invention achieves adaptive adjustment of the sound absorption frequency band, maintains a high sound absorption peak value over a wide parameter range, is suitable for large-area deployment, has a compact structure, and low cost, and can be used for noise control and auditory virtual scenes.

The invention relates to the technical field of focused ultrasound, in particular to a focused ultrasound path optimization method and system for a tumor bone metastasis focus. The method comprises the following steps: firstly, acquiring each candidate sound beam path of a transducer array and a unit path comprising each transducer; further obtaining an energy consumption coefficient according to the spatial distribution and acoustic resistance of voxels on the target path; further obtaining a damage coefficient according to the normal vector deviation corresponding to each skeleton interface voxel on the target path in combination with the spatial distribution of the skeleton interface voxels; further obtaining the path optimization degree according to the overall distribution of the energy consumption coefficient and the damage coefficient; and finally, selecting an optimal sound beam path based on the path optimization degree. According to the method, the energy consumption of each candidate sound beam path and the bone interface injury risk are quantified, the path optimization degree is comprehensively evaluated, automatic optimization of safe and efficient paths in bone metastasis focus focused ultrasound treatment is achieved, and the problem that in the prior art, a multi-path comprehensive optimization mechanism is lacked is solved.

An acoustic absorption structure including at least one cellular structure between an acoustically resistive layer and a reflective layer. The cellular structure includes a first face in contact with the acoustically resistive layer, a second face in contact with the reflective layer, and a multitude of cells each discharging at the level of the first and second faces, each cell being delimited by at least one partition, wherein the cellular structure comprises at least one partitioning enclosure positioned in one of the cells of the cellular structure and connected to at least one partition delimiting the cell. The partitioning enclosure separates an interior zone inside the partitioning enclosure and an exterior zone situated in the cell and outside the partitioning enclosure. The partitioning enclosure includes at least one through-orifice configured so that the interior and exterior zones communicate.

The application discloses a kind of microphone assembly and extractor hood for active noise reduction, and microphone assembly for active noise reduction includes: microphone and flow guide cover, flow guide cover is oppositely arranged with the pickup surface of microphone;There is a gap for pickup between flow guide cover and pickup surface, and the gap is communicated with the pickup hole of microphone.The application is by additionally adding flow guide cover, so that and there is a gap for pickup between flow guide cover and the pickup surface of microphone, sound can directly enter the pickup hole of microphone through the gap, since narrow gap will form acoustic resistance, most airflow flows away from the surface of flow guide cover, a small part of airflow will enter the gap, but flow speed will be reduced, and flow is smooth, without changing flow direction directly from the gap, so airflow will not enter pickup hole, airflow can directly flow out through the gap, avoid producing wind noise, drainage without introducing wind noise, without affecting microphone to collect sound signal, to improve the noise reduction effect of active noise reduction.

This invention discloses a high-resistivity piston-type loudspeaker, belonging to the field of acoustic-to-electric conversion. The invention includes a base 010, a driving component 020, a diaphragm 030, a connecting component 040, and a vibrating cavity 050. The connecting component 040 is not coplanar with the diaphragm 030, i.e., it is a concealed connection structure. The driving component 020 drives the diaphragm 030 to produce a piston-like movement. The diaphragm 030 is located inside the cavity 050, and the displacement range of the diaphragm 030 in the vertical direction is within the cavity height range formed by the support structure extending along the thickness direction of the base, thereby reducing air leakage and increasing the sound pressure level during loudspeaker operation. Based on the piston-type loudspeaker with a concealed connection structure, further optimization of the loudspeaker's diaphragm structure and support structure controls air leakage during loudspeaker operation, further increasing the acoustic impedance of the front and rear cavities and the loudspeaker's output sound pressure level.

This invention relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a bottom electrode; a piezoelectric layer; and a top electrode, wherein: the piezoelectric layer comprises a first layer and a second layer, an acoustic resistive layer is disposed between the first layer and the second layer, the inner edge of the acoustic resistive layer is located inside the boundary of the acoustic mirror in the horizontal direction, the acoustic resistive layer is different from the acoustic resistive layer; and the material of the first layer is different from the material of the second layer. This invention also relates to a bulk acoustic wave resonator assembly, a method for adjusting the electromechanical coupling coefficient of a bulk acoustic wave resonator, a method for adjusting the difference in electromechanical coupling coefficients of resonators in a bulk acoustic wave resonator assembly, a filter, and an electronic device.

Disclosed in the present application are a speaker device, a vehicle audio system, and a vehicle. The speaker device comprises a housing, a speaker mechanism and an acoustic resistance mechanism, wherein the housing is provided with an opening and a sound outlet; the speaker mechanism is arranged in the housing and, together with the housing, forms a cavity, both the opening and the sound outlet being in communication with the cavity; and the acoustic resistance mechanism is arranged in the opening. Sound waves emitted by the speaker mechanism radiate outward from the sound outlet through the cavity; by providing the housing with the opening in communication with the cavity and providing the acoustic resistance mechanism at the opening, Helmholtz resonance in the cavity is mitigated, and the acoustic structure of the cavity is changed, such that peaks and valleys in the frequency response are suppressed, thereby flattening a frequency response curve, improving sound quality. By means of the application of the speaker device, the vehicle audio system has good sound quality. By means of the application of the speaker device or the vehicle audio system, the vehicle has good sound quality.

The invention discloses a structural dry-wet response conversion and underwater noise calculation method based on an acoustic impedance matrix, and the method comprises the steps: obtaining the vibration mode of an overall structure, obtaining a mode shape matrix, carrying out the forced response test of the overall structure, and obtaining the node vibration response of the overall structure. A modal participation coefficient is calculated through inversion or a regularization method, a modal with the modal participation coefficient being 0 is eliminated, response expression is updated, an immersed surface acoustic radiation impedance matrix is calculated, a modal participation coefficient vector after immersion is calculated, underwater vibration response of the structure is calculated, and underwater acoustic radiation is calculated according to immersed surface vibration response distribution and an acoustic radiation acoustic resistance matrix. According to the vibration response of the structure in the light medium and the acoustic impedance matrix of the underwater immersion surface of the structure, the prediction of the underwater vibration response and sound field distribution of the structure is realized; the method can overcome the problems of high difficulty in underwater testing, low fluid-solid coupling calculation efficiency and the like, and is a new method for conveniently and efficiently obtaining the underwater vibration sound response of the structure.

The invention discloses a three-way limiting type sound barrier vibration isolation support, and belongs to the technical field of building vibration reduction and isolation. The support comprises a vibration isolation rubber support upper connecting plate, a vibration isolation rubber support lower connecting plate and a vibration isolation rubber support body formed by overlapping and vulcanizing a plurality of layers of steel plates and rubber. The innovation lies in that a horizontal limiting mechanism is arranged between the upper connecting plate and the lower connecting plate, the mechanism is composed of an inner anti-shearing frame and an outer anti-shearing frame, a friction pair is formed by a polytetrafluoroethylene plate and a stainless steel plate on the mechanism, and horizontal limiting and sound bridge blocking are achieved; the horizontal limiting mechanism is further provided with a vertical limiting mechanism composed of a limiting guide groove and an anti-shearing bolt. The upper connecting plate is provided with a pre-pressing limiting mechanism enabling the support body to be in a pre-compression state. Horizontal and vertical limiting functions are integrated, horizontal vibration and vertical vibration are effectively isolated, meanwhile, a noise transmission path is cut off, and the comfort and safety of building structures such as a subway upper cover are remarkably improved.

A micro-electromechanical systems (MEMS) package comprising: a MEMS package comprising a substate and a lid coupled to the substrate; a piezoelectric valve coupled to the substrate and comprising a number of movable members operable to be deformed in opposite directions upon application of a voltage to modify an acoustic resistance of an acoustic port; and a first stopper defined by the substrate and a second stopper defined by the lid, the first stopper and the second stopper being aligned with the number of movable members and operable to prevent an undesirable deflection of the number of movable members.

The present application relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a bottom electrode; a piezoelectric layer; and a top electrode, wherein: the piezoelectric layer comprises a first layer and a second layer, the second layer is above the first layer in a thickness direction of the resonator; the resonator further comprises a connecting-end acoustic resistance layer provided at an electrode connecting end of the top electrode, an inner edge of the connecting-end acoustic resistance layer is inside an acoustic mirror boundary in a horizontal direction; an outer end edge of the first layer and / or the second layer is inside an outer edge of the connecting-end acoustic resistance layer in the horizontal direction. The present application also relates to a bulk acoustic wave resonator assembly, a filter and an electronic device.

The utility model belongs to the technical field of loudspeakers, and discloses a loudspeaker housing and a loudspeaker, the loudspeaker housing comprises a first housing and a second housing, the first housing comprises a first bottom plate, a first wall plate and a first boss, the first wall plate and the first boss are enclosed on the first bottom plate to form a first accommodating groove, and the second bottom plate is provided with a second accommodating groove. The first shell comprises a first bottom plate, a first wall plate and a first boss, the second shell comprises a second bottom plate, a second wall plate and a second boss, the second wall plate and the second boss define a second containing groove on the second bottom plate, the second boss is provided with a communicating groove, the first boss and the communicating groove define a pressure relief hole, at least part of the pressure relief hole extends in an arc line or a broken line, and the loudspeaker comprises the loudspeaker shell. According to the utility model, the first boss and the communicating groove are enclosed to form the pressure relief hole, so that the pressure relief hole is not limited by the thickness of the side wall of the loudspeaker shell, the processing cost of the pressure relief hole is lower, the size adjustment is more convenient, the acoustic resistance adjustment range at the pressure relief hole is effectively improved, and the acoustic resistance adjustment at the pressure relief hole is simpler and more convenient.

An ultrasonic sensor includes a piezoelectric body, an acoustic impedance matching layer, a stress balancing layer, and a damping body, the stress balancing layer is in contact with the piezoelectric body, the stress balancing layer has a hardness greater than that of the damping body, and the stress balancing layer has an acoustic impedance less than 5 MRayl.

Acoustic absorption structure comprising compartmentalized cells combining several types of resonators. The invention relates to an acoustic absorption structure comprising a honeycomb structure (62), interposed between an acoustically resistive layer (64) and a reflective layer (66), which includes walls (68) delimiting cells (70) and, for at least one cell (70): at least one and at most three L-shaped partitions (72, 72'), impermeable and spaced apart, which delimit a straight compartment (70.1) and at least one L-shaped compartment (70.2, 70.3), in each L-shaped compartment (70.2, 70.3), an inclined acoustically resistive porous partition (80, 80') which has an openness ratio less than or equal to 15% and divides the L-shaped compartment (70.2, 70.3) into first and second zones (80.1, 80.2, 80.1', 80.2') forming two types of resonators. This arrangement increases the frequency range of the processed acoustic waves.The invention also relates to an aircraft comprising at least one such acoustic absorption structure. Figure 7.

The present application relates to the technical field of sound barriers, and provides a wide-frequency optimization method and system for a composite sound barrier and a computer, the wide-frequency optimization method comprising: obtaining a cavity shape correction amount, a neck end effective length correction amount and a thermal viscous acoustic resistance, and constructing a resonator parameterization module; obtaining a target frequency band; obtaining a frequency matching degree term, a bandwidth coverage degree term and a structure compactness term, and composing a multi-objective optimization function; based on the resonator parameterization module and the multi-objective optimization function, using a particle swarm optimization algorithm improved by introducing acoustic structure experience rules and feasible solution priority rules to obtain final resonator size data sets; based on the final resonator frequency, determining a labyrinth passage length, and based on the target frequency band, determining a labyrinth passage cross-sectional size, to design a labyrinth phase modulation plate unit; and constructing a composite sound barrier. Through the above method, a composite sound barrier with low-frequency performance, light structure and wide-frequency coverage can be efficiently designed.

A piezoelectric microelectromechanical system microphone comprises a support substrate, a cantilever sensing element including a piezoelectric material attached to the support substrate and configured to deform and generate an electrical potential responsive to impingement of sound waves on the cantilever sensing element the cantilever sensing element divided into a plurality of cantilevers having gaps between side edges of adjacent cantilevers, and a compliant material disposed in at least a portion of the gaps between adjacent cantilevers to improve the performance of the piezoelectric microelectromechanical system microphone.

This invention provides a packaging structure and fabrication method for a MEMS device. The packaging structure includes: a first carrier; a second carrier, wherein the lower surface of the first carrier is connected to the upper surface of the second carrier, and the two enclose a cavity; a first opening, which is formed on the first carrier; and a metal shielding layer, which is disposed on the first carrier, with a portion of the metal shielding layer surrounding the first opening. By providing a metal shielding layer around the first opening on the packaging substrate, it is more beneficial to absorb ESD arcs around the acoustic aperture, avoiding mechanical damage to the microphone chip caused by ESD arcs. By positioning the MEMS device directly below the first opening, the acoustic cavity, acoustic impedance, and airflow path are better designed, resulting in a higher signal-to-noise ratio (SNR).

The application discloses a piezoelectric micromechanical ultrasonic transducer, and belongs to the technical field of piezoelectric micromechanical ultrasonic transducers.The piezoelectric micromechanical ultrasonic transducer comprises a cavity-free substrate, and a Bragg reflection layer, a seed layer, a bottom electrode, a piezoelectric layer, a top electrode and a protective layer are sequentially stacked on the substrate.The Bragg reflection layer is a multilayer structure formed by alternately stacking a first acoustic impedance material layer and a second acoustic impedance material layer, and the topmost layer of the Bragg reflection layer is the second acoustic impedance material layer.The acoustic resistance of the first acoustic impedance material layer is higher than that of the second acoustic impedance material layer.The piezoelectric micromechanical ultrasonic transducer solves the problems of low structural strength, uneven stress and longitudinal acoustic wave leakage through the substrate caused by the cavity in the existing PMUT, improves the structural strength of the PMUT, avoids stress concentration and improves the Q value, and is beneficial to obtaining a high-performance and high-reliability PMUT device.

The application discloses a kind of precision calculation method and system of carbon fiber cloth surface acoustic impedance, it is related to the cross field of acoustics engineering and composite material technology, including: obtaining the fiber volume fraction of carbon fiber cloth, warp and weft weaving density, fiber diameter, single layer thickness, layer number, adjacent layer stacking angle, back cavity depth and acoustic angular frequency;According to warp and weft weaving density and fiber volume fraction, anisotropic correction coefficient and equivalent weaving density are calculated;Utilize the anisotropic correction coefficient, equivalent weaving density and other parameters to calculate acoustic resistance;Utilize acoustic angular frequency, fiber volume fraction, single layer thickness, fiber diameter, back cavity depth, layer number and stacking angle to calculate acoustic reactance;Acoustic resistance and acoustic reactance are integrated into the surface acoustic impedance of complex number form.The application can accurately adapt single layer, multi-layer stacking configuration carbon fiber cloth, with small calculation error and high calculation efficiency, and can be widely applied to aerospace acoustic lining, high-end equipment noise reduction and other scenes.

The present application relates to a noise-reducing air path structure, an air path device, and a ventilator. The noise-reducing air path structure comprises: an air path cavity; a sound-transmitting and air-blocking member, disposed in the air path cavity and configured to divide the air path cavity into an airflow part and a sound-absorbing part; and a sound-absorbing filler, disposed in the sound-absorbing part and configured to absorb sound that enters the sound-absorbing part from the airflow part through the sound-transmitting and air-blocking member. The present application achieves the effect of reducing noise while also enabling the ventilator to be miniaturized and ensuring the healthiness of the inhaled gas.

This disclosure provides embodiments of a method, apparatus, electronic device, and readable medium for measuring the acoustic impedance of materials. One specific implementation of the method includes: determining a first signal group in a first state and a second signal group in a second state for the material acoustic impedance measuring device; determining a first solution equation and a second solution equation based on the first signal group, the second signal group, and the acoustic impedance solution model corresponding to the material acoustic impedance measuring device; solving the first solution equation and the second solution equation for acoustic impedance parameters to obtain a first solution acoustic impedance and a second solution acoustic impedance; and determining the acoustic impedance of the measurement area of ​​the material to be measured based on the first solution acoustic impedance and the second solution acoustic impedance. This implementation can measure the acoustic impedance of the measurement area of ​​the material to be measured with extremely high accuracy.

The application discloses a micro-gap type adjustable sound absorption device, which comprises a shell and a partition plate arranged between opposite side walls of an inner cavity of the shell, the partition plate divides the inner cavity of the shell into two cavities; further comprising a rotating plate hingedly arranged at the other end of the partition plate, the rotating plate is matched with the inner cavity structure of the other end of the shell when being perpendicular to the axis of the shell, and the rotating plate does not exceed the other end port when rotating; further comprising two back cavity adjusting components arranged in the two cavities of one end of the shell, the space between the two back cavity adjusting components and the rotating plate is a first back cavity and a second back cavity. Through reasonable setting of the component structure, the inner cavity of the shell is divided into two cavities by the partition plate, and the height of the first back cavity and the second back cavity is adjusted through the two back cavity adjusting components in the two cavities, meanwhile, the rotating plate rotates along the rotating shaft to adjust the gap between the rotating plate and the inner wall of the shell, so that the acoustic reactance and the structural acoustic resistance can be matched with the air impedance at different rotating angles, and the adjustable sound absorption can be realized after the noise frequency band changes, and the structure is simple and convenient to operate.

The present application relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a bottom electrode; a piezoelectric layer; and a top electrode, wherein: an overlapping area of the top electrode, the piezoelectric layer, and the bottom electrode in a thickness direction of the resonator constitutes an effective area of the resonator; the piezoelectric layer comprises a first layer and a second layer, an acoustic resistance layer is arranged between the first layer and the second layer, the second layer is above the first layer, an inner edge of the acoustic resistance layer is on an inner side of a boundary of the acoustic mirror in a horizontal direction, an acoustic resistance of the acoustic resistance layer is different from an acoustic resistance of the piezoelectric layer; the resonator further comprises a channel or an opening that communicates the acoustic resistance layer with an outside. The present application also relates to a bulk acoustic wave resonator assembly, a method for manufacturing a bulk acoustic wave resonator, a filter, and an electronic device.

The application discloses a waterproof sound-permeable film assembly, and solves the problem of poor sound-permeable performance of the waterproof sound-permeable film assembly when the waterproof sound-permeable film assembly is subjected to assembly external force or other external force. The waterproof sound-permeable film assembly comprises a waterproof sound-permeable film, a supporting piece, an adhesive piece and a shifting piece. The waterproof sound-permeable film comprises a sound-permeable area and an annular fixing area, and the fixing area is located at an edge area of the waterproof sound-permeable film. The supporting piece is located at two sides of the waterproof sound-permeable film and has an annular structure. The adhesive piece is bonded with the fixing area and the supporting piece. The adhesive piece has an annular structure. The shifting piece is located at a side of the waterproof sound-permeable film close to an external environment, is connected with the supporting piece, and has an annular structure. When external force acts, the shifting piece and the supporting piece have a shifting action. Through the cooperative action of the supporting piece and the shifting piece, the film piece is prevented from being wrinkled when various external forces act, the sound-permeable performance is good, audio consistency is high, and the sound resistance of a high frequency band is small.

The acoustic liner comprises a surface acoustic resistance layer and a plurality of honeycomb core grids with different cavity depths, and the honeycomb core grids with different cavity depths enable the overall height of the acoustic liner to be non-uniform; communication holes are formed in the sides of at least part of the honeycomb core grids, so that one or more adjacent honeycomb core grids are communicated in sequence, and cavity depths with different folding times are constructed; the honeycomb core grids communicated with each other are further provided with partition plates used for transversely dividing the honeycomb core grids. The invention further provides a broadband noise reduction device comprising the acoustic liner and an aero-engine. The acoustic liner can achieve a better broadband noise reduction effect under the condition that the arrangement space is limited.

One subject of the present invention is a method for producing a sound resistance structure (46), a sound resistance structure and an acoustic panel, characterized in that the method comprises the steps of: producing, consolidating and cutting a first layer of reinforcing fibers embedded in a first thermoplastic resin having a first melting point to obtain an intermediate layer (54); laying a second layer of reinforcing fibers against a first face (64.1) of the intermediate layer (54); consolidating the second layer of reinforcing fibers embedded in a second thermoplastic resin to obtain an unperforated outer layer (52) bonded to the intermediate layer (54), the second consolidation temperature of the second thermoplastic resin being lower than the first melting point of the first resin; perforating the outer layer (52); and laying an inner layer (58) on a second face of the intermediate layer (54). Another subject of the present invention is a sound resistance structure obtained by the method and an acoustic panel comprising such a sound resistance structure.