231 results about "Acoustic impedance" patented technology

The invention provides a machine tool machining parameter adjustment method and system, relates to the technical field of machine tool machining parameter adjustment, and aims to infer local acoustic impedance of a workpiece material in real time by emitting sound waves and receiving echo signals on the workpiece material in front of cutting of a cutter and extracting acoustic features. And when the local acoustic impedance is continuously higher than a preset normal reference value and exceeds a preset threshold value, determining that a local abnormal region exists, and generating an early warning signal. And before the tool makes contact with the local abnormal area, the machining parameters are adjusted in advance according to the early warning signal. And real-time feedback signals in the cutting process are continuously monitored, and the machining parameters are further adjusted based on the real-time feedback signals and the early warning signals. The problems that in the prior art, due to uneven local hardness of a workpiece material, a tool is unexpected to be abraded, and machining size deviation is accumulated can be effectively solved.

The invention discloses a wind turbine generator blade damage judgment method and detection system based on voiceprint detection, and belongs to the technical field of wind turbine generator blade detection. The damage judgment method comprises the following steps: acquiring environmental parameters of a wind power plant, and establishing a sound velocity correction model based on the environmental parameters; acquiring a blade resonance sound signal, and correcting the blade resonance sound signal based on the sound velocity correction model to obtain a blade resonance sound signal with a high signal-to-noise ratio; performing FFT spectrum analysis on the blade resonance sound signal with the high signal-to-noise ratio, identifying the peak position of the first three-order natural resonance frequency of the blade, and performing analysis to obtain the current modal frequency, damping ratio and sub-band energy distribution entropy value of the blade; historical baselines of the modal frequency, the damping ratio and the sub-band energy distribution entropy of the blade in the healthy state are obtained, and the modal frequency offset, the damping ratio change rate and the acoustic impedance spectrum entropy of the blade are obtained; and wind turbine generator blade damage determination is carried out by using a high-precision time difference detection technology.

The invention relates to the technical field of material corrosion and protection, discloses a TP2 copper corrosion behavior testing method based on temperature regulation and control, and aims to solve the problem that in the prior art, various physical and chemical parameters in the corrosion process are difficult to synchronously obtain under the same microscale, so that a local corrosion dynamics mechanism cannot be deeply revealed. The core of the system is a coaxial three-function composite probe integrated with thermal, acoustic and electrochemical sensing units, and the coaxial three-function composite probe is matched with a synchronous laser heating module and a multi-physical field synchronous control system. During testing, the probe scans on the surface of a sample, local thermal disturbance is applied to each pixel point, and the interface temperature, acoustic impedance and corrosion rate data of the point are synchronously collected. According to the invention, through high integration in structure and accurate synchronization in time, the space mismatch error of multi-source measurement is eradicated, and multi-physical field distribution images which are accurately corresponding to each other can be obtained in situ and losslessly.

An acoustic matching structure is used to increase the power radiated from a transducing element with a higher impedance into a surrounding acoustic medium with a lower acoustic impedance. The acoustic matching structure consists of a thin, substantially planar cavity bounded by a two end walls and a side wall. The end walls of the cavity are formed by a blocking plate wall and a transducing element wall separated by a short distance (less than one quarter of the wavelength of acoustic waves in the surrounding medium at the operating frequency). The end walls and side wall bound a cavity with diameter approximately equal to half of the wavelength of acoustic waves in the surrounding medium. In operation, a transducing element generates acoustic oscillations in the fluid in the cavity. The transducing element may be an actuator which generates motion of an end wall in a direction perpendicular to the plane of the cavity to excite acoustic oscillations in the fluid in the cavity, and the cavity geometry and resonant amplification increase the amplitude of the resulting pressure oscillation. The cavity side wall or end walls contain at least one aperture positioned away from the center of the cavity to allow pressure waves to propagate into the surrounding acoustic medium.

The invention belongs to the technical field of acoustics, and particularly relates to an index type open-pore rigid plate internal vector sound field calculation method, program and equipment and a storage medium. According to a Webster equation satisfied by a simple harmonic plane sound source excitation sound pressure field, circular piston radiation acoustic impedance on an infinite baffle plate is adopted to represent radiation impedance at an opening of an exponential open pore, a sound field analytical solution of any depth in the open pore of the exponential open pore rigid plate is constructed, system calculation is carried out in combination with sound source conditions, and a sound field of any depth in the open pore of the exponential open pore rigid plate is obtained. Therefore, sound field quantities such as internal accurate sound pressure and vibration velocity of the exponential type open-pore rigid plate under the vertical incidence condition can be quickly solved, and sound field distribution conditions under different section change rules and different open-pore rigid plate sizes can be calculated. According to the method, the calculation complexity is low, the influence problem caused by sound field changes under the non-free field condition can be solved, and the calculation stability and reliability under the complex boundary condition are ensured.

The present disclosure relates to a bulk acoustic wave (BAW) device with electrostatic discharge (ESD) protection. The disclosed BAW device includes a substrate (106), an ESD protection layer (106) over the substrate (106), a first bottom reflector (109-1) over the ESD protection layer (108), a first bottom electrode (112-1) over the first bottom reflector (109-1), a first top electrode (118-1) vertically aligned with the first bottom electrode (112-1), and a piezoelectric layer (116C) vertically between the first bottom electrode (112-1) and the first top electrode (118-1). Herein, the ESD protection layer (108) is electrically insulating and eligible to achieve at least a 400 V breakdown voltage with a 200 nm thickness. The first bottom reflector (109-1) includes a stack of alternating high acoustic impedance conductive layers (120A-E) and low acoustic impedance conductive layers (120A-E). The first bottom electrode (112-1) is electrically connected to the first bottom reflector (109-1). A breakdown voltage of the piezoelectric layer (116C) is no more than the breakdown voltage of the ESD protection layer (108).

The invention discloses an ultrasonic double-wave detection and monitoring method and an ultrasonic double-wave transducer, and the ultrasonic double-wave transducer comprises a piezoelectric element which is used for exciting a longitudinal wave signal and a transverse wave signal at the same time under the excitation of a single electric pulse; the backing layer is positioned on the back surface of the piezoelectric element and is used for absorbing longitudinal wave energy radiated to the back surface by the piezoelectric element; the matching layer is arranged between the piezoelectric element and the tested workpiece and is used for acoustic impedance matching; the electrical connection device is used for connecting an external excitation generator and receiving equipment; and the metal shell is used for packaging the piezoelectric element, the backing layer, the matching layer and the electrical connection device and is provided with a structure for applying pre-tightening force. According to the invention, dual-mode excitation is realized through a single piezoelectric plate structure, and the efficiency, precision and reliability of dual-wave ultrasonic detection are improved.

An acoustic resonator is provided that includes a piezoelectric layer, an interdigital transducer (IDT) including a plurality of interleaved fingers on the piezoelectric layer, a substrate, and an acoustic reflector between the piezoelectric layer and the substrate. The acoustic reflector that is on the piezoelectric layer includes alternating first layers of first materials and second layers of second materials. A first acoustic impedance of the first materials is different from a second acoustic impedance of the second materials. A ratio of a pitch of the IDT over a thickness of the piezoelectric layer is less than 10. A first thickness of at least one of the first layers is larger than a quarter of a first wavelength λ1. λ1 is an acoustic wavelength of a shear bulk wave in the at least one of the first layers at a resonance frequency of the transversely-excited bulk acoustic resonator.

The invention relates to the technical field of building materials, in particular to a bio-based multifunctional sound insulation wallboard and a preparation method thereof. The wallboard comprises a sound absorption layer and a sound insulation layer. The sound absorption layer is cooperatively constructed by an inactivated mycelium three-dimensional porous framework and microalgae biomass, and the sound insulation layer is a high-density complex formed by compounding bio-based raw materials such as wood fiber, straw, recycled paper pulp and shell filler. And the two are combined through a biological-physical mechanical interlocking interface formed by hypha growth, extension and embedding to form a natural acoustic gradient structure from porous low acoustic impedance to compact high acoustic impedance. According to the preparation method, an in-situ growth process of mycelium culture and microalgae coating is embedded into a hot-pressing process, a three-dimensional anchoring network is formed by actively embedding mycelia into the sound insulation layer, the microalgae permeates into pores and is subjected to hot pressing to generate biomacromolecules for bonding and filling, a porous structure is synchronously constructed by a one-step method, and firm interlayer bonding is realized. The wallboard has excellent broadband acoustic performance, stable bonding strength and low-carbon and environment-friendly benefits.

The invention discloses a preparation method of a silicon dioxide-epoxy resin composite material, the acoustic impedance of the composite material is controlled by adjusting the volume fraction of the silicon dioxide-epoxy resin composite material, an ultrasonic transducer prepared by utilizing the composite material and a preparation process thereof, and an imaging system designed by utilizing the ultrasonic transducer. By designing the matching layer and the backing layer with specific acoustic impedance, seamless fusion of ultrasonic imaging and photoacoustic imaging is realized, the transducer has ultrahigh sensitivity, broadband characteristic and high optical transparency, shows bimodal imaging capability of high contrast and high resolution, and solves the problem that a traditional transparent ultrasonic transducer is insufficient in acoustic performance.

The invention relates to a method for forming (P1) a primary stack (30) comprising: a supply step (E1) of an initial stack (10) comprising an initial substrate (11) having a front face (Fav) comprising a central zone (Zc) and a peripheral contouring zone (Zdp), and a resonant thin layer (13) of piezoelectric material; and a protection step (E2), in which a protective thin layer (17) is deposited on the initial stack (10) and covering the peripheral contouring zone (Zdp); the protective thin layer (17) being of a material having an acoustic impedance greater than 20 MRayl for longitudinal waves and / or greater than 12 MRayl for shear waves. The invention also relates to a resonant electronic device (100) and a method (P2) for manufacturing a resonant electronic device (100) from such a primary stack (30). Figure 2

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 invention relates to the technical field of laser intelligent manufacturing, and discloses a laser cladding and cutting combined machining system based on machine learning, which comprises three core units, namely a multi-mode sensing core unit, a central processing core unit and a laser machining execution core unit. The multi-mode sensing unit integrates a scanning galvanometer type thermal infrared imager and a non-contact ultrasonic transducer array, and synchronously collects a surface temperature field and internal acoustic impedance. An acoustic-thermal correlation health model is arranged in the central processing unit, and internal hidden defects are identified on line by comparing health acoustic characteristics predicted by real-time temperature with a measured value. Therefore, the feed-forward parameter planning module fuses the physical state field and the defect identification result, dynamically plans and outputs an optimal process parameter sequence, and drives a laser processing execution unit to complete adaptive processing. According to the method, closed-loop self-adaptive regulation and control are realized through acoustic-thermal multi-mode information fusion and feedforward control, formation of internal defects can be effectively predicted and inhibited, and the quality, consistency and reliability of processed finished products are remarkably improved.

This invention relates to the field of ultra-precision polishing technology, specifically to an ultrasonic cavitation microjet polishing module for polishing microstructures. The module includes an acoustic focusing nozzle, a center-penetrating piezoelectric transducer, an adaptive acoustic impedance frequency tracking system, and a liquid supply and bubble nucleation system. The acoustic focusing nozzle employs a variable cross-section acoustic amplitude rod structure, ensuring that the standing wave antinodes and nozzle outlet are confocal, thus increasing energy density. The piezoelectric transducer has a ring structure with fluid flowing through its center, achieving efficient energy conversion. The frequency tracking system adjusts the excitation frequency in real time to maintain resonance. The liquid supply system introduces cavitation nuclei through a venturi tube, reducing the cavitation threshold. This invention, through an acoustic-fluid coupling mechanism, utilizes the dual effects of macroscopic kinetic energy removal and microscopic cavitation removal to solve the problems of traditional polishing techniques, such as difficulty in processing high aspect ratio microstructures, incomplete bottom polishing, and low efficiency. It achieves high-precision polishing of microstructure surfaces, and is particularly suitable for ultra-precision machining of deep and narrow grooves.

The invention relates to the technical field of collagen intelligent monitoring, and particularly discloses an intelligent collagen monitoring method and system integrated with a microsensor. Enzyme response hydrogel with switchable states is anchored to the skin through a microneedle array, a high-frequency acoustic impedance analysis module is used for continuously probing the acoustic impedance change of the hydrogel, and the collagen monitoring accuracy is improved. Identifying a collagen degradation event; once collagen degradation is detected, the system activates the micro-regeneration unit, a cleaning solution and a regeneration solution are conveyed through a microfluidic channel, a broken peptide chain is removed, a hydrogel cross-linked network is reconstructed, and functional regeneration of the sensing unit is realized; the system further comprises a regeneration state confirmation and cycle reset mechanism, and the reliability of each monitoring cycle and the consistency of data references are ensured. According to the method, the limitation of a traditional monitoring method is overcome, multiple times of recycling of a single sensor is achieved, the credibility and consistency of long-term monitoring data are improved, and the method has important significance on skin health management and senescence research.

This disclosure describes systems, methods, and apparatus for improving the cooldown time, or efficiency of cooling systems, for a low-frequency one or multi-stage pulse-tube refrigerator. More specifically, actuation is performed on the driving frequency of the oscillating pressure and flow, on flow resistance of valves in the acoustic network that terminate the LF-OPTR or LF-DIPTR, and / or on the asymmetric flow resistance of the bypass valves in a LF-DIPTR's flow network. The actuation of these parameters is informed by measurements of the output pressure or output-input differential pressure at the steady flow compressor, the temperature of each stage of the refrigerator, and the temperature difference between the final stage and upper stages of the refrigerator, to name a few non-limiting examples.

The utility model discloses a cover body assembly which comprises a cover body, the cover body is provided with a gas inlet channel and a fuel gas channel, the two ends of the fuel gas channel are correspondingly provided with a gas inlet and a gas outlet, the gas inlet is communicated with the gas inlet channel, and the gas outlet is used for being communicated with a combustion cylinder. Wherein the fuel gas channel is provided with at least one section of narrowing part, the cross sectional area of the narrowing part is smaller than that of the fuel gas channel, and / or the fuel gas channel is provided with at least one section of expansion part, and the cross sectional area of the expansion part is larger than that of the fuel gas channel. Therefore, the change of acoustic impedance can be caused in the acoustic propagation process, and the reflection and interference phenomena of sound waves are generated, that is, the noise generated in the rapid flowing process of fuel gas can be reflected, interfered and the like at the narrowing part or the expansion part, so that the noise generated in the use process of the heat exchanger can be reduced. In addition, the utility model further discloses the heat exchanger with the cover body assembly.

The invention relates to the technical field of power generation devices, and provides a nuclear fuel built-in loop free piston thermo-acoustic generator which comprises a thermo-acoustic engine, a control drum, a neutron reflecting layer and a piston type generator, the thermo-acoustic engine comprises a low-temperature heat exchanger, a heat regenerator and a reactor core which are arranged in sequence, and the reactor core is provided with a channel for working medium gas to circulate; the control drum is arranged on the peripheral side of the thermoacoustic engine; the thermoacoustic engine and the control drum are both arranged in the neutron reflecting layer, the piston type generator is provided with a main piston air cylinder, the main piston air cylinder is in acoustic communication with the outlet end of the thermoacoustic engine through an expansion cavity side resonance tube, and the piston type generator is used for converting part of acoustic power into electric energy and adjusting the acoustic impedance phase angle. The reactor core is directly used as a heat source to be arranged in the thermoacoustic engine, so that the reactor core directly replaces a hot end heat exchanger in the traditional technology, the arrangement of a middle heat transfer structure is avoided, the structure is simple, and the problem of low heat transfer efficiency caused by the heat transfer structure is avoided.

The invention relates to a method and a device for controlling the propagation of sound waves in the vicinity of a wall, the method and the device implementing, by means of a control law, a master device for controlling a set of Nc elementary cells (1) mainly composed of a loudspeaker (11), a set of Nm microphones (10) connected to the loudspeaker and a control unit (12), the control law determining an electrical signal to be sent to each loudspeaker (11) to obtain a target generalized acoustic impedance determined for each loudspeaker, so that a portion of the sound waves is absorbed by the membrane of each loudspeaker (11).

This invention provides an acoustically transparent skull based on the transfer matrix method. The skull includes a matching layer, a coupling layer, and a biomimetic skull. The biomimetic skull matrix has acoustic windows and a stepped groove design for easy and quick assembly, disassembly, and repositioning. The matching layer module is made of epoxy resin-nano-alumina composite material, and its thickness is designed according to a quarter wavelength of the target frequency band. This effectively optimizes acoustic impedance matching and reduces energy loss, becoming a key breakthrough in improving the transmission efficiency of transcranial ultrasound and expanding its application in non-invasive medical fields. This invention focuses on the field of biomechanics and medicine, addressing the problem of low transmission efficiency in transcranial ultrasound technology caused by differences in acoustic impedance of the skull. It can be used to compare the sound transmission effects of single or multiple matching layers at different frequencies. In the future, ultrasound can be more widely used for diagnosis, treatment, neuromodulation, and health / mental status monitoring of astronauts.

The application provides a broadband high sound absorption ceramic nanofiber and a preparation method thereof, and belongs to the technical field of ceramic nanofibers. The ceramic nanofiber takes amorphous silicon aluminum oxide as a matrix skeleton, and the fiber is internally dispersed with micro-nano composite units composed of a porous zinc oxide core and an interfacial gap region around the core. The composite units are in-situ formed by using the differential volume shrinkage between the core-shell structure ZIF-8@SiO2 precursor particles and the silicon aluminum skeleton during heat treatment. The gap region and the porous core in the fiber reduce the equivalent density and the dynamic bulk modulus of the skeleton, improve the acoustic impedance matching between the fiber and air, reduce the surface reflection of sound waves, increase the specific surface area of the fiber, improve the tortuosity of the sound wave propagation path, strengthen the viscous friction and heat conduction dissipation, and are beneficial to expanding the effective sound absorption frequency band.

Provided is an elastic wave device in which peeling of an acoustic reflective film from a piezoelectric layer can be suppressed.　An elastic wave device 1 of the present invention comprises: an acoustic reflective film 4 that contains one or more high-acoustic impedance layers 6a, 6b which have relatively high acoustic impedance and one or more low-acoustic impedance layers 5a-5c which have relatively low acoustic impedance; a piezoelectric layer 7 that is provided on the acoustic reflective film 4 and that has a first main surface 7a and a second main surface 7b which are opposite from each other; and an IDT electrode 8 that is provided on the first main surface 7a of the piezoelectric layer 7 and that has a plurality of electrode fingers (a plurality of first and second electrode fingers 18 and 19). The low-acoustic impedance layers and the high-acoustic impedance layers are alternately layered. The one or more low-acoustic impedance layers 5a, 5b are low-density silicon oxide layers which have a density of less than 2 g / cm3. The low-density silicon oxide layers each have a third main surface 5x and a fourth main surface 5y which are opposite from each other. The acoustic reflective film 4 further contains at least one adhesion layer 11 which is provided between a high-acoustic impedance layer and at least one from among the third main surface 5x and the fourth main surface 5y of a low-density silicon oxide layer. The density of the adhesion layer 11 is higher than the density of a low-density silicon oxide layer which is in contact with the adhesion layer 11, and is lower than the density of a high-acoustic impedance layer which is in contact with the adhesion layer 11.

The application discloses a kind of key parameters of laser piston sound generator sound pressure calculation model determination method, belong to laser piston sound generator technical field, it is by the same one to be measured infrasound sensor and the acoustic coupling of three different lengths of piston cavity of piston sound generator, the response voltage of infrasound sensor is successively collected when different piston cavity length, the ratio of the response voltage of infrasound sensor when different piston cavity length is calculated, and the experimental data of the sound pressure ratio of piston sound generator when different piston cavity length is obtained;According to experimental data, the parameters to be determined in the sound pressure calculation model of piston sound generator are fitted using genetic algorithm, and the key parameters to be determined in the sound pressure calculation model of piston sound generator are obtained.The method can solve the problem of accurate determination of the change of piston cavity volume and additional acoustic impedance introduced by the acoustic coupling of infrasound sensor and piston sound generator, and improve the calculation accuracy of the sound pressure calculation model of laser piston sound generator.

An acoustic blanket absorbs acoustic energy and reduces noise in a launch vehicle. The acoustic blanket may be overlaid on a wall of a payload fairing of the launch vehicle. Materials and construction of the acoustic blanket allow for a relatively thin and light sound barrier. The acoustic blanket may comprise vertically-lapped polyester that is overlaid with a lightweight melamine foam. This combination of materials creates an acoustic impedance mismatch between layers that leads to absorption of acoustic energy across a relatively broad range of frequency bands. The acoustic blanket has a particular heat seal pattern that helps absorb noise while allowing the acoustic blanket to be relatively soft and flexible, which is useful for attaching the acoustic blanket to a curved wall of a fairing or other launch vehicle shapes. The acoustic blanket utilizes micro-perforations on multiple sides to allow for movement of air / venting while maintaining the bulk materials inside.

The application relates to the technical field of surface acoustic wave devices, in particular to a structure and method for suppressing bulk acoustic wave interference in a multilayer SAW resonator, which comprises a support substrate, a bonding layer, a piezoelectric layer and an interdigital transducer, a reflective grating and an RF signal pad arranged in sequence from bottom to top; wherein an acoustic impedance matching and attenuating layer is arranged between the RF signal pad and the piezoelectric layer, and the acoustic impedance matching and attenuating layer is a single dielectric layer or a periodic multilayer film alternately stacked by two or more dielectric materials with different acoustic characteristics, and the material of the single dielectric layer is silicon dioxide or doped silicon dioxide. The application sets the acoustic impedance matching and attenuating layer between the RF signal pad and the piezoelectric layer, so as to effectively absorb and scatter the bulk acoustic wave energy generated below the pad, convert the bulk acoustic wave energy into heat energy, significantly weaken the bulk acoustic wave intensity, and improve the overall performance and consistency of the SAW device in high-frequency communication applications.

The noise reduction device provided by the embodiment of the invention comprises a first air inlet, an air duct and a first air outlet, wherein the air duct comprises an air duct interval and a plurality of sub air ducts; the air channel interval is made of at least two different materials, and air reaches the first air outlet from the first air inlet through the multiple sub air channels. According to the embodiment of the invention, the larger air duct is divided into the plurality of sub-air ducts through the air duct interval, the air duct interval is made of at least two different materials, gas reaches the first air outlet from the first air inlet through the plurality of sub-air ducts and is exhausted, and the plurality of materials are combined to form the plurality of slender sub-air ducts; broadband noise generated by various gas flow rates can be reduced, the noise generated by various gas flow rates can be controlled at an ideal level, the contact area between gas and the partition wall surface of the air duct is increased through the multiple slender sub-air ducts, the gas flow rate in each slender sub-air duct is reduced, the vortex size is reduced, and the vortex effect is improved. When gas enters the area where the plurality of slender sub-air ducts are located, the acoustic impedance changes, and the noise level is effectively reduced.

The utility model provides an air conditioner pipe with a built-in silencer, and belongs to the technical field of automobile parts. The hush pipe is arranged in the body pipeline, one end of the hush pipe is connected with the air inlet connector of the air inlet end of the body pipeline, the other end of the hush pipe is suspended, and the interval is formed between the other end of the hush pipe and the air outlet end, so that when air flow enters from the air inlet connector and enters the inner cavity of the body pipeline through the hush pipe, the air flow enters the inner cavity of the body pipeline; due to the fact that airflow enters the large inner cavity from the small inner cavity, acoustic impedance changes can be caused through changes of the section of the pipeline, noise reduction is achieved through interference counteracting of generated reflected sound waves and original sound waves, meanwhile, a plurality of protruding noise reduction joints are arranged on the outer side wall of the noise reduction pipe, reflection and scattering of the sound waves are achieved through the noise reduction joints for multiple times, and noise reduction is achieved. The airflow turbulence is reduced, the airflow velocity is maintained, the energy consumption is reduced, meanwhile, additional space occupation and pipeline arrangement are not needed, additional space occupation is avoided, a pipeline system is simplified, and later maintenance is facilitated.

The invention discloses a loudspeaker array beam forming method, electronic equipment and a storage medium, and relates to the technical field of beam forming, and the method comprises the steps: obtaining a distance value between each loudspeaker unit in a loudspeaker array and a corresponding impedance boundary, and an impedance value of the impedance boundary; matching a target beam forming filter in a plurality of preset beam forming filters according to the distance value and the impedance value; and filtering the input signal of the corresponding loudspeaker unit based on each target beam forming filter to form an output beam. In practical application, the applicable beam forming filter can be quickly matched only by acquiring the specific impedance boundary parameters of the current environment, the method can adapt to the boundary environment with limited acoustic impedance characteristics, the influence of the impedance boundary on sound wave propagation is accurately reflected, the beam pointing precision and the acoustic contrast are remarkably improved, and the method is suitable for popularization and application. And the grating lobes of the dark area are reduced, so that the optimization of the beam performance is realized on the premise of not needing on-site acoustic measurement, and the universality and the accuracy are both considered.

The present invention provides an active inductive impedance enhancement circuit applied to a power line path. It utilizes a closed-loop control technique to detect residual high-frequency signals on the power line and generates a compensation current injected into the secondary side of the main inductor accordingly. The invention actively suppresses high-frequency current flowing through the main inductor, thereby significantly enhancing its impedance against high-frequency noise.

The invention discloses a laser welding strong co-processing method and tool for a stranded conductor. The method sequentially executes five working procedures that radial compression force and axial pretension are applied to the stranded conductor to construct quasi-materialization constraint, and preheating is conducted; laser welding is executed in the local inert gas microenvironment, and the temperature of a molten pool is monitored; a sacrificial absorption layer is arranged, a deionized water restraint layer is injected, and a flexible anvil block loaded with liquid metal-based magnetorheological fluid is arranged on the back of a conductor; the magnetic field intensity is dynamically adjusted according to the material of a processing area, reflection is inhibited by using carrier liquid acoustic impedance matching in a low-impedance metal section, a backing is in a quasi-solidified state to absorb shock wave residual energy through magnetic particle chaining in a high-impedance metal section, and laser shock peening is executed; and after strengthening, the compression force is unloaded to recover micro-pores among the strands, so that the through-layer drying of stranding gaps is realized. According to the invention, multi-physical field cooperation of machinery, fluid, acoustics and thermodynamics is realized, and the process stability and service reliability of the joint are improved.