189 results about "Acoustical impedance" patented technology

The invention is directed biopsy site markers and methods of marking a biopsy site, so that the location of the biopsy cavity is readily visible by conventional imaging methods, particularly by ultrasonic imaging. The biopsy site markers of the invention have high ultrasound reflectivity, presenting a substantial acoustic signature from a small marker, so as to avoid obscuring diagnostic tissue features in subsequent imaging studies, and can be readily distinguished from biological features. The several disclosed embodiments of the biopsy site marker of the invention have a high contrast of acoustic impedance as placed in a tissue site, so as to efficiently reflect and scatter ultrasonic energy, and preferably include gas-filled internal pores. The markers may have a non-uniform surface contour to enhance the acoustic signature. The markers have a characteristic form which is recognizably artificial during medical imaging. The biopsy site marker may be accurately fixed to the biopsy site so as to resist migration from the biopsy cavity when a placement instrument is withdrawn, and when the marked tissue is subsequently moved or manipulated.

IntraOsteal UltraSound (IOUS) is the use of acoustical energy to facilitate “real-time” manipulation and navigation of a device for intraosseous placement of synthetic or biologic implants and to diagnose the condition of the tissue into which the implant is being placed. Representative applications include placement of synthetic or biologic implants, such as bone screws, through vertebral pedicles during spinal fusion surgery. Devices for use in the placement of the implants include a means for creating a lumen or channel into the bone at the desired site in combination with a probe for providing realtime feedback of differences in density of the tissue, typically differences in acoustical impedance between cancellous and cortical bone. The devices will also typically include means for monitoring the feedback such as a screen creating an image for the surgeon as he creates the channel, and / or an audible signal which different tissues are present. The system can also be used for diagnostic applications.

An acoustic wave resonator device comprising a resonant layer that comprises a series of side-by-side areas of first and second dielectric materials. In one embodiment the first dielectric material is a piezoelectric, in particular the first dielectric material can be a piezoelectric and the second dielectric material can be non-piezoelectric. In another embodiment, the first dielectric material is a piezoelectric of first polarity and the second dielectric material is a piezoelectric of opposite polarity or different polarity. Where needed, the resonant layer is supported on a reflector composed of series of layers of high acoustic impedance material(s) alternating with layers of low acoustic impedance material(s). For example, the reflector comprises AlN, Al2O3, Ta2O5, HfO2 or W as high impedance material and SiO2 as low impedance material.

An elastic wave device propagating plate waves includes a stack of an acoustic reflection layer, a piezoelectric layer, and IDT electrode on a supporting substrate. The piezoelectric layer is thinner than a period of fingers of the IDT electrode. The acoustic reflection layer includes low-acoustic-impedance layers and high-acoustic-impedance layers. The low-acoustic-impedance layers are made of SiO2, and the high-acoustic-impedance layers are made of at least one material selected from the group consisting of W, LiTaO3, Al2O3, AlN, LiNbO3, SiN, and ZnO.

The invention is a method of estimating, from data obtained by exploration of a zone of a heterogeneous medium, a model representative of a distribution, in the zone, of at least one physical quantity, the model being free of a presence of correlated noises that may be contained in the data which has application to determining the distribution in an underground zone of acoustic impedance, propagation velocities and permeabilities, etc. The method includes acquiring measurements giving information about physical characteristics of the zone; specifying a noise modelling operator which associates, with a model of each physical quantity, synthetic data that constitute a response of the model; selecting a noise modelling operator which associates a correlated noise with a noise-generating function belonging to a predetermined space of the noise-generating functions; specifying a norm or of a semi-norm in the data space; specifying a semi-norm in the space of the noise-generating functions; defining a cost function; and adjusting the model and of the noise-generating functions.

A method for manufacturing an acoustical stack for use within an ultrasound transducer comprises using a user defined center operating frequency of an ultrasound transducer that is at least about 2.9 MHz. A piezoelectric material and a dematching material are joined with an assembly material to form an acoustical connection therebetween. The piezoelectric material has a first acoustical impedance and *at least one of* an associated piezoelectric rugosity (Ra) and piezoelectric waviness (Wa). The dematching material has a second acoustical impedance that is different than the first acoustical impedance and at least one of an associated dematching Ra and dematching Wa. The piezoelectric and dematching materials have an impedance ratio of at least 2. The assembly material has a thickness that is based on the center operating frequency and at least one of the piezoelectric Ra, piezoelectric Wa, dematching Ra and dematching Wa.

A method for manufacturing an acoustical stack for use within an ultrasound transducer comprises using a user defined center operating frequency of an ultrasound transducer that is at least about 2.9 MHz. A piezoelectric material and a dematching material are joined with an assembly material to form an acoustical connection therebetween. The piezoelectric material has a first acoustical impedance and *at least one of* an associated piezoelectric rugosity (Ra) and piezoelectric waviness (Wa). The dematching material has a second acoustical impedance that is different than the first acoustical impedance and at least one of an associated dematching Ra and dematching Wa. The piezoelectric and dematching materials have an impedance ratio of at least 2. The assembly material has a thickness that is based on the center operating frequency and at least one of the piezoelectric Ra, piezoelectric Wa, dematching Ra and dematching Wa.

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.

It is an object of the present invention to provide an ultrasonic transducer, which is so configured as to reduce the variations in characteristics, thereby to enable the stabilization of the precision, as well as to enable the improvement of the durability, and the like, a method for manufacturing the ultrasonic transducer, and an ultrasonic flowmeter. In order to attain this object, in accordance with the present invention, the ultrasonic transducer is so configured as to include a piezoelectric element and an acoustic matching layer, wherein the acoustic matching layer is made of a dry gel of an inorganic oxide or an organic polymer, and a solid skeletal part of the dry gel has been rendered hydrophobic. With this configuration, it is possible to obtain the ultrasonic transducer having an acoustic matching layer 3 which is very lightweight and has a small acoustic impedance due to the solid skeletal part of the dry gel which has been rendered hydrophobic. Further, it is also possible to obtain the ultrasonic transducer which shows a narrow range of characteristic variations, and is stable due to the high homogeneity of the dry gel.

A device for determining the internal structure of a bone along a path directed into the bone (or other tissue) is disclosed. The device comprises a nozzle fluidically connected to a liquid reservoir for providing a liquid jet directed at the bone in the direction of the path; an ultrasonic transducer for generating ultrasonic waves through the liquid jet and for detecting echoes of the ultrasonic waves caused by changes in the acoustical impedance in the bone characterizing changes in the structure of the bone along the path; and an analyzer for interpreting the echoes into meaningful information relating to the location of the structural changes along the path.

A method of inspecting a component, the component comprising a hole with an entrance. The method comprises: directing ultrasound into the component via a liquid coupling medium; receiving ultrasound from the component via the liquid coupling medium; and processing the received ultrasound to determine a property of the component. The entrance of the hole is sealed with tape to prevent the liquid coupling medium from flowing into the entrance of the hole.The tape has an acoustic impedance within 40% of the acoustic impedance of the liquid coupling medium. By selecting a tape with an acoustic impedance relatively close to that of the liquid coupling medium (which in most cases will be water) the tape is relatively transparent to ultrasound and thus enables at least the presence or absence of a defect in a wall of the hole to be determined.

A system and method for improving the efficiency and effectiveness of the transmission of acoustical energy to process fluids during substrate processing, such as cleaning or photoresist stripping. The invention utilizes a layered stack of materials to transmit acoustical energy from a source of acoustical energy to the process fluid. The material of which each layer is constructed is chosen so as to reduce the differences in acoustical impedance between consecutive layers of the stack, providing a more gradual transition, in terms of acoustical impedance, when acoustical energy is being transmitted from the source to the process fluid. In one aspect, the invention is a system comprising: a process chamber for receiving a process fluid; an acoustical energy source; and an acoustical stack having a first transmission layer and a second transmission layer that forms an acoustical energy pathway from the acoustical energy source to the process fluid in the process chamber.

The invention relates to a method for measuring particle concentration and sizes on the basis of an ultraphonic impedance spectrum. The method comprises that steps that 1, a theoretical impedance real component spectrum is obtained through an ECAH model and theory; 2, a theoretical curve of particle size-resonant frequency and a theoretical curve of a concentration-resonant amplitude are obtained; 3, an acoustic impedance spectrum is obtained from experiments according to an ultrasonic transducer and calculation, a real time component is taken from the acoustic impedance spectrum, and an experimental impedance real component spectrum is obtained; treatment is conducted on signals obtained from the experiments through a formula in the third step, resonant frequency for measuring the object impedance real component spectrum can be obtained, the resonant frequency fR is extracted, and the concentration and the particle size of a measured object can be obtained from the curves of the particle size-resonant frequency and the concentration-resonant amplitude determined in the second step. According to the method for measuring the particle concentration and sizes on the basis of the ultraphonic impedance spectrum, a system is simple in structure and low in cost, online measurement can be achieved, and the method can be used for the laboratory science research; compared with utilizing the ultrasonic attenuation and phase velocity, the method is more suitable for measurement of particles in a high concentration two-phase mixture.

The invention discloses a method for simultaneously measuring multiple parameters of a linear visco-elastic thin layer material by employing an ultrasonic flat probe. The method comprises the steps: 1) immersing a referred base material and the linear visco-elastic thin layer material in water, placing the ultrasonic flat probe respectively right above the referred base material and the linear visco-elastic thin layer material to measure and obtain reflection echo s0(t) and s1(t); 2) performing low-pass filtering on s0(t) and s1(t); 3) performing optimum estimate on echo s11(t) which belongs to s1(t) and comes from the upper surface of the linear visco-elastic thin layer material, so as to obtain an optimum measured value Zm2 of acoustic impedance, and subtracting a corresponding s11(t) from s1(t) when the acoustic impedance is equal to Zm2; and 4) performing optimum estimate on echo s12(t) which belongs to s1(t) and comes from the lower surface of the linear visco-elastic thin layer material, so as to obtain optimum measured values delta tm2 and alpha m2 of transit time and attenuation coefficient. The method helps to avoid the fitting convergence domain problem frequently appeared in conventional measuring methods based on reflection coefficient spectrum fitting, and is suitable for measuring acoustics characteristics of thin layer materials.

The invention provides a sound absorption unit and a sound absorption device. The sound absorption unit comprises at least one quarter-wavelength tube bank body and at least one Helmholtz resonator row body which are arranged in a stacked mode in the preset direction; the quarter-wave tube bank body comprises a plurality of quarter-wave tubes arranged side by side, and each quarter-wave tube is provided with a first open end and a first closed end which are oppositely arranged; the Helmholtz resonator row body comprises a plurality of Helmholtz resonators arranged side by side, and each Helmholtz resonator is provided with a second open end and a second closed end which are oppositely arranged; the first open ends and the second open ends are adopted to jointly form a sound wave incident surface of the sound absorption unit; and in the preset frequency band, the overall acoustic impedance of the sound absorption unit is matched with the acoustic impedance of the air. The sound absorption unit can achieve a good sound absorption effect at a low frequency band, space can be saved, the preparation cost is reduced, and environmental pollution is reduced.

An ultrasonic transducer according to the present invention includes: a piezoelectric body 4 to set up ultrasonic vibrations; an acoustic matching layer 3 made of a material with a density of 50kg / m3 to 1,000 kg / m3;and an acoustic impedance of 2.5x103kg / m2 / s to 1.0x106kg / m2 / s ; a lower acoustic matching layer 9 provided between the piezoelectric body 4 and the acoustic matching layer 3; and a structure supporting member 6 that supports the lower acoustic matching layer 9 and the piezoelectric body 4 thereon and shields the piezoelectric body 4 from a fluid that propagates the ultrasonic vibrations. The ultrasonic transducer includes a protective portion, which contacts with at least a portion of a side surface of the acoustic matching layer 4. This protective portion is defined by a portion of the lower acoustic matching layer 9 and forms an integral part of the lower acoustic matching layer 9.

Disclosed is an ultrasound probe which outputs ultrasound on a basis of a drive signal which is to be received. The ultrasound probe including a composite piezoelectric layer in which a piezoelectric material and a polymer material are arranged alternately in a one-dimensional array or in a two-dimensional array, an acoustic reflection layer which has an acoustic impedance higher than an acoustic impedance of the composite piezoelectric layer and an adhesion layer which bonds the composite piezoelectric layer and the acoustic reflection layer wherein in a bonding surface of the composite piezoelectric layer that bonds with the acoustic reflection layer, a polymer material part is concaved in a direction opposite to an acoustic reflection layer side comparing to an piezoelectric material part.