14results about "Impedence" patented technology

A method in which an acoustic sensor disposed in a polishing apparatus can be accurately calibrated is disclosed. In this method, polishing sounds of a substrate are acquired using an acoustic sensor; and then at least two distinctive sounds, having distinctive frequencies respectively, are selected from the acquired polishing sounds. Further, the at least two distinctive sounds are output from a sound source coupled to any of a polishing table, the acoustic sensor, and a substrate holder to cause the at least two distinctive sounds to be input to the acoustic sensor. Next, output values of the acoustic sensor are calibrated, such that the output values of the acoustic sensor relative to the at least two distinctive sounds come within an allowable range.

This disclosure relates to porous matrices for acoustic impedance matching and improved touch sensing and fingerprint imaging. The invention discloses the use of acoustic impedance matching to improve the accuracy of ultrasonic touch sensing and fingerprint imaging. Acoustic impedance mismatch between the ultrasonic transducer array and the sensing plate can be reduced to maximize energy transfer and minimize parasitic reflections. Reduction of acoustic impedance mismatch can be achieved using: (i) a composite epoxy resin having a higher acoustic impedance than epoxy resin alone; (ii) one or more matching layers having an acoustic impedance approximately equal to the geometric mean of the acoustic impedance of the sensing plate and the acoustic impedance of the transducer array; (iii) holes or perforations in the sensing plate; or (iv) a geometry formed in the sensing plate. Furthermore, an absorbent layer can be used to suppress parasitic reflections.

The application provides a method for reducing and controlling the sound wave impedance of isotropic material, belongs to the technical field of material sound wave impedance, and solves the problem of difficulty in detecting gas characteristics.The technical scheme comprises the following steps: step one, selecting isotropic material;step two, obtaining the motion equation of the isotropic material;step three, using a plane wave to solve a differential equation, and obtaining the sound wave impedance Z of the material according to a sound wave impedance definition formula;step four, rotating a vector Omega = {0, eta omega, 0} to represent rotating the material along an x2 axis, and rotating a vector Omega = {0, 0, eta omega} to represent rotating the material along an x3 axis;step five, changing the sound wave impedance of the material under the condition of rotating the axis.The beneficial effects of the application are as follows: the application can introduce the Coriolis force caused by rotation into the motion equation of the isotropic material, find the relationship between the sound wave impedance and rotation, and use rotation to reduce and control the sound wave impedance.

A resonator-boosted ultrasonic transducer device is provided for communication of ultrasonic signals. The device employs a micromachined ultrasonic transducer (MUT), such as a piezoelectric MUT (pMUT) or capacitive MUT (cMUT), and a matching network in electrical communication with the MUT. The matching network employs a microelectromechanical (MEMS) resonator having a working frequency selected to increase a voltage difference across electrodes of the MUT. The matching network is connected in series between the MUT and input source circuitry for transmission of outgoing ultrasonic signals. The matching network is connected between the MUT and load impedance circuitry to increase voltage from the MUT during reception of incoming ultrasonic signals. The matching network can be selected to configure the frequency of bandwidth of the device as desired for a particular application.

A sensor for measuring the viscoelastic properties of a material comprises a rigid support (10) and a membrane (11) fixed to the support (10), the material being intended to come into contact with an outer face (111) of the membrane (11). The sensor further comprises an active assembly (12) having at least one piezoelectric element bonded to an inner face of the membrane (11), the active assembly (12) being configured to generate the oscillation of the membrane (11) according to a resonance mode greater than or equal to the second resonance mode of the membrane (11). Method for measuring the viscoelastic properties of a material and method for monitoring milk coagulation using such a sensor. Figure for the abstract: Fig. 2

The application relates to a wheel hub resonant cavity noise reduction performance evaluation method, electronic equipment and a medium, and belongs to the wheel hub production technical field, wherein the method comprises the following steps: equivalent propagation of an acoustic wave in a tire cavity to a plane wave, calculating acoustic impedance of each resonant cavity according to obtained geometric parameters of the resonant cavity; calculating total acoustic impedance after parallel connection of the resonant cavities based on the acoustic impedance; equivalent of a main cavity to a straight pipe with equal cross-sectional area and length equal to the circumference of the main cavity, calculating a transmission loss curve of the acoustic wave varying with frequency when the acoustic wave propagates a cycle distance in the straight pipe based on the total acoustic impedance and obtained geometric parameters of the main cavity, and evaluating the wheel hub resonant cavity noise reduction performance based on the transmission loss curve. The application can calculate the transmission loss curve of the acoustic wave varying with frequency in the tire cavity by inputting characteristic dimensions of the tire cavity, and further accurately predict the noise reduction effect of the resonant cavity after actual installation.

The application discloses a mirror image multimodal direct extraction method for measuring acoustic liner acoustic impedance, and relates to the technical field of acoustic liner acoustic impedance measurement. The method is that a broken line array microphone is arranged on the opposite wall of an acoustic liner to simultaneously collect axial and lateral sound field information of a sound field, a multimodal Prony algorithm is used to realize full-modal decomposition of a three-dimensional multimodal sound field, a trust region method is introduced to solve an equation set, and finally, the acoustic liner acoustic impedance is analytically extracted. In this way, the lateral spacing of the array can be significantly improved, more sound field information can be obtained, the lateral modes can be better distinguished, the precision of the acoustic impedance extraction is significantly improved, the 3 kHz upper limit of the NASA method can be broken, the acoustic impedance extraction frequency under the three-dimensional multimodal aerodynamic sound field is greatly improved, and the extraction problem under nearly 10 kHz is solved.

This invention relates to the field of transformer measurement and testing, specifically to a method and system for detecting core loosening in amorphous alloy transformers. First, vibration, current, and temperature data are simultaneously acquired, and wavelet packet decomposition is used to extract the vibration energy characteristics of fine frequency bands. Then, a magnetostrictive model is constructed by combining the load current and its rate of change to obtain the equivalent excitation potential energy, and the nonlinear effects of load and temperature are decoupled by calculating the structural response impedance spectrum. Based on this, the trapezoidal integral method is used to calculate the hysteresis loop area of ​​impedance changing with temperature, quantifying the thermo-mechanical nonlinear loss of the core, and finally obtaining normalized detection indicators for graded early warning. This invention can effectively eliminate interference from varying operating conditions, accurately capture the loosening characteristics of the core caused by thermal accumulation effects, and significantly improve the robustness and accuracy of monitoring.

Improving the accuracy of ultrasonic touch sensing and fingerprint imaging using acoustic impedance matching is disclosed. Acoustic impedance mismatches between an ultrasonic transducer array and a sensing plate can be reduced to maximize energy transfer and minimize parasitic reflections. A reduction in acoustic impedance mismatches can be accomplished using (i) a composite epoxy having a higher acoustic impedance than epoxy alone, (ii) one or more matching layers having an acoustic impedance that is approximately the geometric mean of the acoustic impedance of the sensing plate and the acoustic impedance of the transducer array, (iii) pores or perforations in the sensing plate, or (iv) geometric structures formed in the sensing plate. In addition, parasitic reflections can be suppressed using an absorbent layer.

This invention discloses a mechanical impedance testing device and method for an internally pressurized elastic straight tube structure, comprising a fixing mechanism, a first elastic straight tube, a second elastic straight tube, a docking cover plate, and an output mechanism. The fixing mechanism includes a left support frame and a right support frame. The first and second elastic straight tubes have identical structures and are horizontally and symmetrically arranged between the left and right support frames. The two sides of the docking cover plate are respectively connected to the input ends of the first and second elastic straight tubes, and a through hole is opened in the middle of the docking cover plate to connect the internal chambers of the first and second elastic straight tubes. The output mechanism is located between the output end of the second elastic straight tube and the right support frame, and includes an upper adapter plate, a three-dimensional force plate, and a lower adapter plate arranged sequentially. This device and method not only avoid the stiffness influence of the introduced decoupling airbag but also avoid the influence of fluid pressure transmission inside the elastic tube, thus improving the accuracy of the test results.

Disclosed is a monitoring device. More specifically, the present invention relates to a monitoring device including a microphone array for detecting, in consideration of surrounding situations, sources of noise exceeding a threshold that may occur on outdoor roads, factories, and the like, and a noise control system using same. According to an embodiment of the present invention, a conventional CCTV camera, which is installed on a road to monitor vehicles in motion, is provided with a weather observation means and an outdoor noise measurement means, and there is an effect of detecting, by means of same, a sound source that generates noise greater than or equal to a threshold by determining surrounding conditions such as weather.

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 present application aims to provide an unauthorized intrusion sensing device, which comprises: a plurality of bodies (110) arranged at selected positions of a sensing area; a plurality of blocking ropes (120) connecting the bodies (110) to each other in a horizontal direction and arranged in a manner that they are spaced apart by a predetermined interval in a vertical direction for blocking unauthorized intrusion; and a detection unit (130) formed to be capable of pulling a plurality of the blocking ropes (120) in a specified direction to keep them in a tensioned state, thereby detecting a change amount generated due to shaking or cutting of the blocking ropes (120) during unauthorized intrusion. The present application has the effect that the ropes are pulled in a specified direction to keep them in a tensioned state with a weak tension, thereby enabling immediate detection and sensing of the shaking or cutting state of the ropes occurring during unauthorized intrusion to take prompt subsequent measures.

According to the invention, a sensor (1) of acoustic waves propagating through a liquid is optically sensitive to variations in the density of the liquid that are produced by pressure variations related to the passage of an acoustic wave. The sensor is designed to be threaded through a wall (102) of a pipe, for example of a water distribution network. The sensor may be used to detect leaks of the liquid at distance from a location of installation of the sensor, or to adjust an intensity of an acoustic wave used to detach a deposit present on a surface making contact with the liquid.