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56results about How to "Low speed of sound" patented technology

Electroacoustic Transducer having Reduced Losses due to Transverse Emission and Improved Performance due to Suppression of Transverse Modes

ActiveUS20130051588A1Degradation in transfer functionReduce shear loadPiezoelectric/electrostrictive device manufacture/assemblyImpedence networksTransducerTransverse mode
An electroacoustic transducer has reduced loss due to acoustic waves emitted in the transverse direction. For this purpose, a transducer comprises a central excitation area, inner edge areas flanking the central excitation area, outer edge areas flanking the inner edge areas, and areas of the busbar flanking the outer edge areas. The longitudinal speed of the areas can be set so that the excitation profile of a piston mode is obtained.
Owner:SNAPTRACK

Flow measurement system with reduced noise and crosstalk

A flow measurement system including at least first and second ultrasonic transducers coupled to an existing conduit, a damping material about the conduit between the first and second ultrasonic transducers to prevent crosstalk, a damping material about the conduit upstream of the first ultrasonic transducer to attenuate system background noise travelling in the conduit at large, and a damping material about the conduit downstream of the second ultrasonic transducer to attenuate system background noise travelling in the conduit at large.
Owner:GE INFRASTRUCTURE SENSING

Silica aerogels and their preparation

Silica aerogels with improved properties are disclosed together with methods for synthesizing such aerogels. The improved properties include lower thermal conductivity (better insulating capacity), lower acoustic velocity, lower dielectric constant and improved ductility. Greater tunability of the refractive index can also be achieved. The silica aerogels are prepared by a sol-gel processing method that provides better control of the formation of aerogel structures. Generally speaking, the improvements arise from control of the synthesis to create a morphology of primary clusters and diverse-sized secondary clusters of dense silica aerogels separated by less densely packed regions. By providing a broader range of secondary clusters and / or pore sizes and loose connectivity between clusters, reductions can be achieved in thermal conductivity and flexural modulus.
Owner:MASSACHUSETTS INST OF TECH

Cyclonic liquid degassing separator and method for degassing a fluid mixture

A method and cyclonic separator are disclosed for degassing a fluid mixture comprising a carrier liquid and gaseous and / or vaporizable components, wherein: the fluid mixture is accelerated in a throat section (6, 21) of a vortex tube (1, 20) such that the static pressure of the fluid mixture is decreased and vaporizable components evaporate into a gaseous phase and the fluid mixture flows as a substantially homogeneously dispersed gas-liquid mixture through the throat section; the accelerated fluid mixture is induced to swirl within a tubular mid section of the vortex tube such that the fluid mixture is separated by centrifugal forces into a degassed liquid fraction and a gas enriched fraction; the degassed liquid fraction is induced to flow into a annular liquid outlet conduit (4, 21); and the gas enriched fraction is induced to flow into a central gas outlet conduit (3, 24). An advantage of inducing the fluid mixture to flow as a substantially homogeneously dispersed gas-liquid mixture through the throat section is that the velocity of sound in such a mixture is low, thereby increasing the Mach number and the pressure reduction in the throat section and enhancing evaporation of gas bubbles in the mixture.
Owner:SHELL OIL CO

Ultrasonic non-destructive testing method for measuring circumference residual stress at gear root

The invention provides an ultrasonic non-destructive testing method for measuring circumference residual stress at root, the method is suitable for the non-destructive measurement of residual stress at the gear root. An LCR (critically refracted longitudinal) wave which is most sensitive to the stress is motivated through the combination of an ultrasonic stress measurement system, an ultrasonic transducer and a wedge block, and the residue stress at the region is precisely computed by using acoustic time difference of the LCR wave for detecting whether the stress is near to the root. The method is capable of accurately, fast and non-destructively detecting the residue stress value.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Giant magnetostictive longitudinal-torsional coupled vibration ultrasonic transducer

The invention discloses a giant magnetostictive longitudinal-torsional coupled vibration ultrasonic transducer which comprises a transducer main body, a coil support and a shell, wherein the shell comprises a top plate, a base plate as well as a plurality of giant magnetostictive bar installation pipes, a plurality of giant magnetostictive bars, a first magnetic conduction sheet, a second magnetic conduction sheet, an upper cover plate, a lower cover plate, a fastening element, a magnetic element and a coil; the plurality of giant magnetostictive bar installation pipes are arranged between the top plate and the base plate; the plurality of giant magnetostictive bars are respectively installed in the giant magnetostictive bar installation pipes; the coil is reeled on the coil support; the coil and the fastening element are coaxial; and an ultrasonic frequency alternating current is introduced into the coil so as to generate an alternating magnetic field to drive the giant magnetostictive bars to generate longitudinal-torsional coupled vibration. According to the giant magnetostictive longitudinal-torsional coupled vibration ultrasonic transducer provided by the embodiment of the invention, parts are reduced; and the structure of the transducer is simplified, so that the structure of the transducer is compact, and the ultrasonic energy can be transmitted efficiently.
Owner:深圳市青鼎装备有限公司

Argyrodite thermoelectric material and preparation method thereof

The invention relates to an argyrodite thermoelectric material, the chemical formula of which is Ag8Sn(1-x)NbxSe6, x=0-0.05. The preparation method of the argyrodite thermoelectric material is characterized by, with simple substances being raw materials, carrying out material blending according to stoichiometric ratio of the chemical formula; after vacuum packaging, melting reaction quenching and thermal treatment quenching, grinding ingots into powders; and carrying out vacuum high-temperature hot-pressure sintering, and after slow cooling, obtaining a block material, which is the argyrodite thermoelectric material. Compared with the prior art, the high-performance thermoelectric material, which is low in heat conduction and high in thermoelectric performance, is prepared, and the method for preparing the thermoelectric material, which is high in density, high in mechanical strength and high in thermoelectric performance, is explored; the thermoelectric material has very low lattice thermal conductivity (0.2-0.4 W / m.K) in a whole-temperature range; when the temperature is 900 K, thermoelectric peak of the thermoelectric material reaches 1.2; when the temperature is 300-850 K, the average thermoelectric figure of merit zTave of the thermoelectric material is infinity-0.8; and the argyrodite thermoelectric material is a potential thermoelectric material.
Owner:TONGJI UNIV

Fluted linear shaped charge with simultaneous initiation

This patent relates to lined shaped explosive devices, in particular it relates to linear Shaped Charges (SC), more particularly it relates to a Fluted or Scalloped Linear Shaped Charge. The fluted linear SC, unlike a standard linear SC produces hydrodynamic penetration, higher jet velocities, higher mass jets and deeper penetration. The fluted linear device disclosed herein produces greater compression and convergence of the liner material because of the partial radial collapse of the concave flutes. Further, the fluted linear SC is equipped with a simultaneous initiation of the full length of the explosive driving the liner, providing smooth detonation wave front along the full length of the fluted linear liner.
Owner:COLLIER NICHOLAS

High-speed rotary ultrasonic torsional processing device

The invention discloses an ultrasonic processing device, in particular to a high-speed rotary ultrasonic torsional processing device which comprises an output shaft and a transmission shaft. A rare-earth rod and tubular piezoelectric ceramic are mounted in an inner bore of the output shaft from inside to outside along an axial direction sequentially. An induction coil is wound on the output shaft, a coil former and an outer sleeve are arranged on the outer side of the transmission shaft, a closed coil storage chamber is formed by the coil former and the outer sleeve, and an excitation coil is disposed in the coil storage chamber. The ultrasonic torsional processing device which is manufactured on the basis of rare earth magnetostriction materials and piezoelectric ceramic materials is connected with a spindle of a machine, is subjected to two-dimensional ultrasonic mechanical vibration while driving a tool head to rotate at high speed, and thus, ultrasonic torsional processing of workpieces is achieved. Besides, the device realizes high-speed rotary ultrasonic torsional processing, ultrasonic frequency band is wide, ultrasonic energy is high, running state is stable, ultrasonic vibration amplitude can be regulated by changing magnetic field intensity and prepressure, and accordingly requirements of different processing precisions can be met.
Owner:ZHONGBEI UNIV

Aerogel honeycomb sandwich board

The invention relates to an aerogel honeycomb sandwich board. The aerogel honeycomb sandwich board is composed of an upper-layer panel (3), a lower-layer panel (3) and a middle aerogel honeycomb core body. The aerogel honeycomb sandwich board is resistant to fire and flames, achieves heat insulation, and is good in sound insulation performance, high in strength and resistant to compression; the aerogel honeycomb sandwich board is good in anti-impact performance, low in mass and environmentally friendly, and has good application prospects.
Owner:SUZHOU ZIAN METAL PROD

Cyclonic liquid degassing separator and method for degassing a fluid mixture

The invention is a method and cyclonic separator for degassing a fluid mixture comprising a carrier liquid and gaseous or vaporizable components. In this method, the fluid mixture is accelerated in a throat section of a vortex tube such that the static pressure of the fluid mixture is decreased and vaporizable components evaporate into a gaseous phase and the fluid mixture flows as a substantially homogeneously dispersed gas-liquid mixture through the throat section; the accelerated fluid mixture is induced to swirl within a tubular mid section of the vortex tube such that the fluid mixture is separated by centrifugal forces into a degassed liquid fraction and a gas enriched fraction; the degassed liquid fraction is induced to flow into an annular liquid outlet conduit; and the gas enriched fraction is induced to flow into a central gas outlet conduit.
Owner:SHELL OIL CO

Method for preparing double-layer anti-reflection film for silicon solar cell

The invention relates to a method for preparing a double-layer anti-reflection film for a silicon solar cell and belongs to the technical field of new energy materials. According to the method, a urethane acrylate modified SiO2 film is employed, the urethane acrylate has a urethane bond, the invention is characterized in that a plurality of hydrogen bonds can be formed between polymer molecular chains, the double-layer anti-reflection film has high wear resistance, adhesion, flexibility, high peel strength and excellent low-temperature resistance performance and the excellent optical performance and weather resistance of polyacrylate, a modified second layer anti-reflection film has excellent mechanical wear resistance and flexibility, and the breaking elongation is high. According to theinvention, the silver mirror reaction is used and the annealing treatment is combined, silver nanoparticles are prepared on the surface of a substrate to be a first layer anti-reflection film, the formation of the silver nanoparticles in random distribution is a result of the combined action of metal thermodynamics and kinetics, and when the rapid annealing is carried out, a silver film system acquires sufficient kinetic energy and tends to have nanoparticle structure with a small surface area.
Owner:陈君

Method for regulating and controlling residual stress of high-speed rail wheel set tread through high-energy acoustic beams

The invention provides method for regulating and controlling residual stress of high-speed rail wheel set treads through high-energy acoustic beams. The method is suitable for non-destructive reduction of wheel set tread stress. According to the method, an ultrasonic stress regulation and control system and an ultrasonic transducer are combined, so that the high-energy acoustic beams sensitive to stress is stimulated, according to high-energy ultrasonic plasticity inductive effect, high-energy ultrasonic wave dynamic energy is supplied to dislocation atoms in stress applying regions or residual stress regions so as to provide enough power, the dislocation atoms overcome resistance and slide out of crystals, so that crystal lattice distortion is reduced, and the purpose of reducing the applying stress or the residual stress is achieved. The method has an obvious effect, has no special requirements for the surface quality of the wheel set to be regulated and controlled, and is harmless to human bodies and environments, and the regulation and control time is short, the in-situ regulation and control operation can be realized, and the on-site operation is convenient and simple.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Ultrasonic nondestructive detection method of high-speed railway wheel pair tread stress

The invention provides an ultrasonic nondestructive detection method for measuring high-speed railway wheel pair tread stress. The method is applied to the nondestructive measurement of wheel pair tread residual stress. Through the combination of an ultrasonic stress measurement system, an ultrasonic transducer and a wedge, an LCR wave which is most sensitive to the stress is excited. Through an acoustic time difference of the LCR wave with and without the stress near tread, the residual stress of an area is calculated. The residual stress can be accurately and rapidly detected in a nondestructive way.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Elastic boundary wave device

ActiveCN1745516ALow speed of soundImprove electromechanical coefficientImpedence networksTemperature coefficientSpeed of sound
An elastic boundary wave device employing an SH type elastic boundary wave having a large electromechanical coupling coefficient, a low propagation loss, a small power flow angle, a temperature coefficient of frequency TCF in an appropriate range, and a simple structure which can be produced through a simple process. A dielectric is deposited on one side of a piezoelectric and an IDT and a reflector are arranged as electrodes on the boundary of the piezoelectric and the dielectric, wherein the thickness of the electrodes is set such that the sound velocity of the SH type elastic boundary wave becomes lower than the sound velocity of a slow transverse wave propagating through the dielectric and the sound velocity of a slow transverse wave propagating through the piezoelectric.
Owner:MURATA MFG CO LTD

Refrigerant compressor

The invention relates to a refrigerant compressor, comprising a compressor housing (1) that am be hermetically capsuled, and a compressor-motor unit (4) arranged in the housing interior (3) of the compressor housing (1), which is elastically mounted on an inner side of the compressor housing (1) by way of at least one spring element (5), wherein at least one damping element (9) made of an elastomer is provided, in order to damp the transmission of vibrations caused by the compressor-motor unit (4) to the compressor housing (1). The at least one damping element (9) is made of an elastomer tied is softer compared to polyamide (PA), polybutylene terephthalate (PBT), ethylene chlorotrifluoroethylene (ECTFE).
Owner:SECOP GMBH

Wireless passive temperature sensing system for main transformer cabinet of electric locomotive

InactiveCN112179518ARealize online temperature monitoring functionAchieve readThermometer detailsThermometers using physical/chemical changesGratingTransformer
The invention discloses a wireless passive temperature sensing system for a main transformer cabinet of an electric locomotive. The wireless passive temperature sensing system comprises a surface acoustic wave temperature sensing unit, an antenna unit and an acquisition unit, the surface acoustic wave temperature sensing unit is mounted at a to-be-measured temperature in a main transformer cabinetof the electric locomotive, and is connected with the acquisition unit through the antenna unit; and the surface acoustic wave temperature sensing unit comprises a substrate, a piezoelectric substrate, an antenna module, an interdigital transducer and a reflecting grating. The piezoelectric substrate comprises a sound wave conduction substrate and a piezoelectric film positioned on the sound waveconduction substrate; the sound wave conduction substrate is located on the substrate, and the antenna module, the interdigital transducer and the reflecting grating are located on the piezoelectricfilm; and a sound absorption layer is laid on the surface of the piezoelectric film and used for absorbing bulk acoustic wave signals in the acoustic surface waves. The system has the advantages of high frequency, low time delay, high sound velocity, high reliability, high adaptability and the like.
Owner:ZHUZHOU NAT INNOVATION RAILWAY TECH CO LTD

Non-invasive assessment of liver fat by crawling wave dispersion

Using a modified ultrasound device, crawling waves are applied to the liver over a range of shear wave frequencies. Dispersion measurements are obtained that reflect tissue viscosity and these correlate with the degree of steatosis. A device for the process has an actuator on either side of the ultrasound transducer to apply shear waves, which interfere to produce the crawling waves.
Owner:UNIVERSITY OF ROCHESTER

Small-hole type pulse tube thermoacoustic refrigerator

The invention relates to a small-hole type pulse tube thermoacoustic refrigerator, which includes a compressor, a hot-end heat exchanger, a regenerator and a cold-end heat exchanger. A compression cavity of the compressor, the hot-end heat exchanger, the regenerator and one end of the cold-end heat exchanger are connected in sequence, the other end of the cold-end heat exchanger is connected withone end of a resonant tube and one end of a pulse tube, the other end of the resonant tube is connected with a first gas reservoir, the other end of the pulse tube is connected with a second gas reservoir, and a small-hole valve is arranged between the pulse tube and the second gas reservoir. Compared with the prior art, according to the small-hole type pulse tube thermoacoustic refrigerator, low-temperature gas expanding for work is added through the pulse tube, and the small-hole valve at the hot-end of the pulse tube can adjust the refrigerating capacity; the resonant tube, under the low temperature, connected with the cold-end heat exchanger plays a phase-regulating role, and due to the low temperature, the acoustic work loss caused by viscous resistance and heat transfer is very small; and thus the efficiency of the thermoacoustic refrigerator can be improved through the structure of connecting the pulse tube and the small-hole valve to the cold-end heat exchanger of the thermoacoustic refrigerator.
Owner:TONGJI UNIV

Performance apparatus

There is provided a performance apparatus that is capable of reducing mechanical noise by a simple construction. Rotary picks are disposed in the vicinity of and in association with respective ends of a plurality of reeds, and four driving nails are formed integrally with outer peripheries of the rotary picks. A hook part is attached to the top of a plunger, and they make reciprocating motions together. The rotary pick is rotated by a driving force applied to the driving nail thereof from an engaging part formed by a lower end of the corresponding hook part. When the driving nail located symmetrically to the driving nail having received the driving force plucks the corresponding reed, the reed is sounded. The hook part is almost completely covered with a cushioning member formed of an elastic material such as rubber to absorb an impact that may occur when the driving nail of the rotary pick comes into contact with the hook part.
Owner:YAMAHA CORP

Wide low frequency acoustic absorber with folding space

The invention provides a wide low frequency acoustic absorber with the folding space. The acoustic absorber includes a casing, a porous material layer and a winding body structure, wherein a top plateof the casing is a rigid perforation panel, the surface of the rigid perforation panel is provided with a through hole penetrating through an inner portion of the casing, a bottom plate of the casingis a rigid back plate, a sound absorbing cavity is formed inside the casing, the porous material layer and the winding body structure are disposed in the sound absorbing cavity, the porous material layer is disposed above the winding body structure, a gap is formed between the porous material layer and the winding body structure, the winding body structure includes two opposite rigid wall surfaces, opposite surfaces of the two rigid wall surfaces are provided with rigid plates which are perpendicular to the height direction of the casing in the height direction at equal intervals, the rigid plates on the two rigid wall surfaces are staggered, and the space between the rigid wall surfaces is divided into an S-shaped air passage. The acoustic absorber is advantaged in that the porous material layer and the winding body structure are integrated into one, and the relatively good noise abatement noise reduction effect is achieved.
Owner:NANJING UNIV OF POSTS & TELECOMM

Electronic component

ActiveUS20200295731A1Reducing or preventing loss of the acoustic wave elementLeakage current is able to be further reduced or preventedImpedence networksSolid-state devicesElectronic componentPiezoelectric membrane
An electronic component includes a support member, a piezoelectric film, and an interdigital transducer. The support member includes silicon as a primary component. The piezoelectric film is provided directly or indirectly on the support member. The interdigital transducer includes a plurality of electrode fingers. The plurality of electrode fingers are provided side by side separately from each other. The interdigital transducer is provided on the principal surface of the piezoelectric film. The film thickness of the piezoelectric film is about 3.5λ or less, where λ denotes the wavelength of an acoustic wave determined by the electrode finger pitch of the interdigital transducer. In the support member, the high-impurity-concentration region is further from the piezoelectric film than the low-impurity-concentration region.
Owner:MURATA MFG CO LTD

Polycrystalline SnSe2 low-cost thermoelectric material and preparation method thereof

The invention relates to a polycrystalline SnSe2 low-cost thermoelectric material and a preparation method thereof. The thermoelectric material has a chemical formula of SnBrxSe(2-x), wherein x = 0-0.05; the preparation method of the thermoelectric material comprises the steps of: adopting a simple substance and SnBr2 as raw materials, performing proportioning according to the stoichiometric ratioin the chemical formula, performing vacuum packaging, melt reaction quenching and heat treatment quenching, grinding the quenched mixture into powder, performing vacuum high-temperature hot-pressingsintering, and performing slow cooling to obtain a block material which is the thermoelectric material. Compared with the prior art, the invention prepares the high-performance anisotropic thermoelectric material with low thermal conductivity and a high thermoelectric property, and the method is explored for preparing the anisotropic thermoelectric material which has high density, high mechanicalstrength and a high thermoelectric property; the thermoelectric material can reach a thermoelectric peak value at a temperature of 750 K, the zT in the direction parallel to hot pressing is 0.65, thezT in the direction perpendicular to hot pressing is 0.40, and therefore the thermoelectric material is a kind of thermoelectric material which has great potential.
Owner:TONGJI UNIV

Increased effective aperture for receive arrays

A sonar dome having an acoustic array housed therein. A plurality of bubbles are generated within the fluid inside the sonar dome. The generated bubbles are of an amount and size to reduce the speed of sound within the sonar dome fluid. Reduction of the speed of sound within the sonar dome fluid effectively increases the aperture of the acoustic array. The bubbles can be generated from a gas source or electrolytically. Typically, each individual bubble is less than 0.01 mm in diameter to reduce bubble velocity in the fluid.
Owner:THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY

Underwater acoustic waveguide

A system and method for generating an underwater acoustic waveguide suitable for guiding acoustic energy between a source and a receiver to enable underwater communications. Electrolysis of water by electrically powered terminals continuously creates a bubble field having a volume fraction of less than 0.01% gas. The bubble field has a lower sound speed than the surrounding water, resulting in the bubble field acting as a waveguide to transmit sound over the length of the bubble field. By maintaining small bubble radii, the bubble field can be stable for long periods of time. By keeping the volume fraction and bubble radii small, the power requirements for the terminals are minimized.
Owner:THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY
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