159 results about "Air coupled" patented technology

A physiological sensing stethoscope suitable for use in high-noise environments is disclosed. The stethoscope is designed to be substantially matched to the mechanical impedance of monitored physiological activity and substantially mismatched to the mechanical impedance of air-coupled acoustic activity. One embodiment of the stethoscope utilizes a passive acoustic system. Another embodiment utilizes an active Doppler system. The passive and active systems can be combined in one stethoscope enabling switching from a passive mode to an active mode suitable for use in very high-noise environments. The stethoscope is suitable for use in environments having an ambient background noise of 100 dBA and higher. The passive includes a head having a housing, a flexural disc mounted with the housing, and an electromechanical stack positioned between the housing and the flexural disc in contact with the skin of a patient. The active system detects Doppler shifts using a high-frequency transmitter and receiver.

A remote, non-contact system for detecting a defect in a railroad wheel as the wheel is stationary or moving along a railroad track includes; (1) a pulsed, laser light source for generating an ultrasonic wave in the wheel, the ultrasonic wave having a direct portion and reflected and transmitted portions if the direct portion encounters a defect in the wheel, (2) an optical component in the path of the light from the light source for forming the light into a specified illumination pattern so that the generated ultrasonic wave has a specified wavefront, (3) an air-coupled transducer or a group of transducers for sensing the acoustic signal emanating from the wheel that results from the ultrasonic wave traveling through the wheel, and (4) a signal processor, responsive to the sensed acoustic signal, capable of distinguishing whether the sensed signal has a component that indicates the existence of a reflected portion in the ultrasonic wave, wherein the presence of such a component in the acoustic signal indicates the existence of a defect in the railroad wheel.

A full-face vehicular detection method for a railway tunnel lining and a device aim to avoid collision of ground penetrating radar antennas with an overhead line system and a support of the overhead line system, the detection speed is a normal running speed of a train, the antennas in full-face detection are not interfered with each other, automatic positioning is realized during detection, only ground penetrating radar signals in a tunnel need to be acquired, and a penetrating radar signal processing and analyzing method in tunnel detection is modified. The vehicular device comprises a six-channel high-speed scanning penetrating radar, a positioning portion, a laser ranging portion and data acquisition and processing software. The pulse repetition frequency of the ground penetrating radar is 3MHz, the pulse repetition frequency of each channel is 500kHz, and the scanning rate is 976scan / s. The ground penetrating radar is provided with TEM (transverse electric and magnetic field) short-horn air coupled antennas, each group of antennas realizes a double-transmission and single-receiving function, and the center frequency of the antennas is 300MHz. The ground penetrating radar antennas are mounted outside passenger train connectors, radiation surfaces of the antennas respectively face to an arch crown, arch springing and side walls, and the full-face vehicular detection method and the device are used for automatically detecting to exam the railway tunnel lining.

A scintillation block detector employs an array of optically air coupled scintillation pixels, the array being wrapped in reflector material and optically coupled to an array of silicon photomultiplier light sensors with common-cathode signal timing pickoff and individual anode signal position and energy determination. The design features afford an optimized combination of photopeak energy event sensitivity and timing, while reducing electronic circuit complexity and power requirements, and easing necessary fabrication methods. Four of these small blocks, or “miniblocks,” can be combined as optically and electrically separated quadrants of a larger single detector in order to recover detection efficiency that would otherwise be lost due to scattering between them. Events are validated for total energy by summing the contributions from the four quadrants, while the trigger is generated from either the timing signal of the quadrant with the highest energy deposition, the first timing signal derived from the four quadrant time-pickoff signals, or a statistically optimum combination of the individual quadrant event times, so as to maintain good timing for scatter events. This further reduces the number of electronic channels required per unit detector area while avoiding the timing degradation characteristic of excessively large SiPM arrays.

The invention belongs to the technical field of tunnel detection of railway engineering systems and particularly relates to a method and a rail vehicle for full-section comprehensive detection of railway tunnels. The rail vehicle comprises a rail vehicle floor board, a cab and a carriage. Line-scan cameras are arranged on an arch frame which is arranged on the rail vehicle floor board, air-coupled shield antennas, and a GPS (global positioning system) mainframe, ground penetrating radar and infrared thermal imagers are arranged on the rail vehicle floor board. A GPS receiver is arranged at the top end of the cab, a laser scanner is arranged at the tail of the top plate of the carriage, and an industrial personal computer is arranged in the carriage. By multiple detection systems, one-time full-section detection of tunnel lining states and tunnel bottom damages can be realized, high detection accuracy, high efficiency, shortening of maintenance time and saving of maintenance cost are realized, influences on normal transportation of the railway tunnels are low, and loss caused by stopping of transportation is reduced.

Formed Laser Sources (FLS) using pulsed laser light for generation of ultrasonic stress waves are combined with air-coupled detection of ultrasound to provide for the hybrid non-contact, dynamic and remote ultrasonic testing of structural materials, especially railroad tracks. Using this hybrid technique, multimode and controlled frequency and wavefront surface acoustic waves, plate waves, guided waves, and bulk waves are generated to propagate on and within the rail tracks. The non-contact, remote nature of this methodology enables high-speed, fill access inspections of rail tracks. The flexibility and remote nature of this methodology makes possible the detection of critical cracks that are not easy, or impossible to detect, with current inspection techniques available to the railroad industry.

Acoustic thermography uses a housing configured for thermal, acoustic and infrared radiation shielding. For in-situ applications, the housing has an open side adapted to be sealingly coupled to a surface region of a structure such that an enclosed chamber filled with air is defined. One or more acoustic sources are positioned to direct acoustic waves through the air in the enclosed chamber and towards the surface region. To activate and control each acoustic source, a pulsed signal is applied thereto. An infrared imager focused on the surface region detects a thermal image of the surface region. A data capture device records the thermal image in synchronicity with each pulse of the pulsed signal such that a time series of thermal images is generated. For enhanced sensitivity and / or repeatability, sound and / or vibrations at the surface region can be used in feedback control of the pulsed signal applied to the acoustic sources.

There is an air coupled ultrasonic contactless method and an installation for non-destructive determination of defects in laminated structures with a width (W) and a multiplicity of n lamellas with intermediate N−1 bonding plants (B), whereas at least one transmitter (T) in a fixed transmitter distance (WTS) radiates ultrasound beams at multiple positions and at least one receiver (R) in a sensor distance (WSR) is receiving re-radiated ultrasound beams at multiple positions relative to the laminated structure (S). The method images the position and geometry of for example lamination defects and allows for inspection of laminated structure (S) of arbitrary height (H) and length (L), and an individual assessment of specific bonding planes (e.g. B1, B2, B3), as well in situations with constrained access to the faces of the sample parallel to the bonding planes.

A hybrid inspection system and method are provided which utilize both an air-coupled transducer and a liquid-coupled transducer in order to enjoy the advantages offered by both types of transducers. The hybrid inspection system may include a first probe that includes the air-coupled transducer, such as a capacitive machined ultrasonic transducer, which is configured to emit ultrasonic signals and to air couple the ultrasonic signals into a workpiece. The hybrid inspection system may also include a second probe that includes the liquid-coupled transducer, such as a piezoelectric transducer, configured to receive the ultrasonic signals emitted by the air-coupled transducer of the first probe via a liquid coupling between the transducer and the workpiece.

The invention discloses a laser ultrasonic thickness measuring method and a laser ultrasonic thickness measuring device capable of being used for field detection. The laser ultrasonic thickness measuring method is characterized in that a laser beam is sent out by a laser to excite an ultrasonic wave on the surface in a specific position of a measured object; meanwhile, an excited wave signal and an echo wave signal produced on the surface in the position are received by an air coupling sensor on the same side of the measured object as the laser; and the propagation distance of the ultrasonic wave is calculated according to the time difference between the excited wave signal and the echo wave signal, and a longitudinal wave propagation velocity of the measured object, so that thickness measurement of the specific position is realized. The device mainly comprises the laser, a main supporting seat, the air coupling sensor, a supporting rod, a centering device, a signal processing system and a display system. The device has a simple and light structure, and can meet the requirements of field detection; and through the adoption of the non-contact type detection method, the thicknesses of high temperature and high-corrosive measured objects can be measured.

The invention discloses a sheet air coupled ultrasonic Lamb wave total-focusing imaging detection method. Different from traditional ultrasonic array signal acquisition, only aiming at a single soundvelocity medium, propagation time of sound waves in air needs to be taken into consideration for acquisition of air coupled array signals. Therefore, the sound velocity ca in the air and the propagation speed cg of the Lamb wave in a plate are measured by using a standing wave method and a wave velocity method respectively. The acquired air coupled ultrasonic Lamb wave array signals exist in the form of a three-dimensional matrix Nti x Ntj x A, the acquired air coupled ultrasonic Lamb wave array signals are subjected to division of an imaging grid region, according to the arrangement positionof a probe, the defect position, and the sound wave propagation speed, the delay time of each scanning path is calculated, and delay superposition total-focusing imaging of the signals is realized according to a delay rule of the sound waves. According to the method, the high-quality ultrasonic total-focusing technology is expected to be expanded to the sheet air coupled ultrasonic Lamb wave imaging detection, so that the defect detection capability is effectively improved.

A high throughput, positive pressure, gravity operated dewatering system for hydraulic fluids, lubricating fluids, and petroleum based fluids comprises a gravity operated dewatering chamber receiving the industrial fluid and a source of positive pressure drying air coupled to the dewatering chamber.

Methods for reducing clicking of ultrasonic air-coupled transducers in which a mechanical filter that attenuates audible frequencies relative to ultrasonic frequencies is placed in the path of the ultrasonic waves as the travel from the transducer to a target such as an object in the vehicle compartment.

The invention relates to a device suitable for measuring the sound field characteristics of an air-coupled ultrasonic detection transducer, which solves the problem of calibration of the sound field characteristics of the air-coupled ultrasonic transducer and realizes automatic measurement of the focal length, focal area length and focal area width of the transducer's sound field. and sound beam spread angle characteristics. The sound field measurement device of the present invention includes: a scanning mechanism, an ultrasonic transceiver and signal acquisition system, a motion control system, a sound axis alignment mechanism, and a micro-hole silencer. The ultrasonic transceiver mode of the measurement system is a transmit-receive mode, and is carried out in a closed transparent chamber. During measurement, the receiving transducer is installed on a fixed bracket, and the measured air-coupled transducer is installed through the acoustic axis alignment mechanism. The sound beam axis is adjusted to coincide with the Z-axis. The pulse sound field emitted by the air-coupled ultrasonic transducer is received by the receiving transducer with a micro-hole silencer attached. The peak value of the pulse echo signal is calculated by the computer through the data acquisition card, and this voltage peak is used as the sound pressure of the acoustic signal. amplitude. The computer drives the ultrasonic transducer to perform spatial scanning motion relative to the receiving aperture through the motion control system, and the spatial sound field sound pressure distribution of the air-coupled ultrasonic transducer can be measured.

The invention discloses an air-coupled transducer based on an air-based 1-3 type piezoelectric composite material. The transducer comprises a 1-3 type piezoelectric composite material wafer, electrodes, a transmission layer, a damping layer, an impedance matching circuit, a transducer shell and a BNC (bayonet nut connector) interface, wherein the electrodes are plated on the surface of the 1-3 type piezoelectric composite material wafer and are concentrically adhered to a matching layer and the damping layer; meanwhile, lead wires led out of the upper and lower electrodes are connected with the BNC interface through the impedance matching circuit. By adopting an air filling mode, instead of a mode of combining a polymer and piezoelectric columns, the 1-3 type piezoelectric composite material taking air as a base body is formed; the sound impedance of the 1-3 type piezoelectric composite material is close to that of the air, so that the energy transmission rate between the transducer and the air can be increased; meanwhile, a fiber material with the sound impedance which is higher than that of the piezoelectric composite material and lower than that of the air is used as the matching layer, so that ultrasonic waves transmitted into the air during excitation are further increased.

A system to perform measurements on liquids, meat, viscous sugar or starch-based materials, and other foodstuffs using air-coupled ultrasound is provided. The technique uses ultrasonic transducers (advantageously capacitive transducers with polymer membranes), to generate ultrasonic signals in air, and to receive these signals after they have passed through the material under test. An ultrasonic pulse-compression process is then applied to increase the sensitivity of signals transmitted through the materials.

The invention relates to car frame traveling type shield tunnel wall post-grouting detection equipment. The equipment comprises a car frame traveling type automatic transmission device, an air-coupled ground penetrating radar and a wall post-grouting body intelligent processing analysis software. The equipment is integrated by hardware and software, and achieves wall post-grouting layer real-time visual detection in the shield construction process. The car frame traveling type automatic transmission device mainly includes a track, a synchronous belt, a transmission mechanism, a servo extension and drive, and a reducer; by carrying a novel air-coupled radar detection device installed on a shield first section car frame, circumferential detection and grouting body layered visual display are conducted on the shield grouting body with shield driving.

The invention discloses an air-coupled low-profile circularly-polarized dielectric lens antenna. The air-coupled low-profile circularly-polarized dielectric lens antenna is composed of three layers of dielectric plates, a square metal layer is arranged on the upper surface of the dielectric plate on the top layer, and a periodic rhombus gap is further formed in the square metal layer; a metal patch in the shape of an equilateral triangle is arranged on the lower surface of the dielectric plate on the middle layer, and the center of the metal patch is overlapped with the center of the dielectric plate on the middle layer; a microstrip line for feeding extending to the center along one side of the dielectric plate on the bottom layer is arranged on the lower surface of the dielectric plate on the bottom layer; the upper surface of the dielectric plate on the bottom layer is covered with a metal layer as an earth plate, and a cross-shaped gap is formed in the central position of the earth plate. According to the air-coupled low-profile circularly-polarized dielectric lens antenna, the impedance bandwidth, gain bandwidth and circular polarization bandwidth of the dielectric lens antenna are greatly improved. Moreover, through the design of a partial reflection surface, the reflection phase of the partial reflection surface in an antenna working frequency band is reduced, so that the height of the antenna is reduced, and low profile of the antenna is realized.

The invention discloses a method for increasing air-coupled ultrasonic detection signal strength of a composite material. The method comprises the following steps: step one, placing a workpiece between a first air-coupled transducer and a second air-coupled transducer; step two, sticking two thin layers on the upper and the lower surfaces of the workpiece; step three, stimulating the first air-coupled transducer, enabling the ultrasonic waves emitted by the first air-coupled transducer to pass through upper side air, the upper side thin layer, the workpiece, and the lower side thin layer and lower side air in sequence, and reaching to the second air-coupled transducer; and step four, feeding back a signal received by the second air-coupled transducer to a computer and generating an image and data; the invention provides a method and technology for conducting impedance matching on the detected workpiece, so that ultrasonic waves reflected back and forth in the thin layers are kept in the same phase when transmitting the thin layers, so as to realize the enhanced energy transmission effect similar to the resonance and improve the detection sensitivity of a whole detection system, and thin layer materials can be recycled.

An air-coupled transducer includes a ultrasonic transducer body having a radiation end with a backing fixture at the radiation end. There is a flexible backplate conformingly fit to the backing fixture and a thin membrane (preferably a metallized polymer) conformingly fit to the flexible backplate. In one embodiment, the backing fixture is spherically curved and the flexible backplate is spherically curved. The flexible backplate is preferably patterned with pits or depressions.

The invention provides, in one aspect, a loudspeaker that has electrodynamically-driven piston mounted in one external wall and that has movable panels in one or more other external walls. Those panels are air-coupled to the piston, e.g., via air within the enclosure, such that vibrational motion of the piston causes the vibration of the panels, thereby, improving the overall air coupling of the piston to the external environment, e.g., the listening room. Further aspects of the invention provide an improved driver for use, e.g., in the aforementioned loudspeaker. The driver comprises a three-part piston having first and second diaphragms coupled back-to-back with one another and having a voice coil face-mounted (or front-mounted) within the second diaphragm.

An air-coupled ultrasonic phased array detection device, the transmission signal is sent to the air-coupled ultrasonic probe by the ultrasonic transmitter receiver, and the ultrasonic wave excited by the probe is incident into the inside of the test piece at a certain angle; The wave signal is received by the ultrasonic probe and transmitted to the signal receiver. The signal is amplified by the preamplifier and enters the data processing unit. After delay superposition and imaging processing, the imaging of the scanning result at a certain angle is completed. Scanning in multiple angles and depth directions can be completed through different emission pulse settings without moving the probe, and a wide range of detection results can be obtained from the content of the tested specimen. Because the air-coupled ultrasonic probe is used, there is no need to touch the detection surface during work, which prolongs the service life of the probe; through the parameter setting of the transmission waveform in the early stage, the length of the focal column, the size of the focus and the direction of the sound beam can be optimally controlled. It has certain advantages in terms of ratio and defect detection rate.

The invention discloses a capacitive coupling device and a filter. The capacitive coupling device comprises a plurality of solid media monomers, the adjacent media units are spliced together, At leastone adjacent dielectric monome is provided with a capacitively couple structure on that splicing surface, the capacitive coupling structure includes a first blind hole and a first air coupling windowwith a surface unmetallized, The depth of the first blind hole is greater than or equal to 1 / 2 of the depth of the first air coupling window and less than the depth of the first air coupling window,a metal shielding layer is arranged on the inner wall of the first blind hole, and the first air coupling window is arranged on the two sides and the bottom of the first blind hole. Blind holes and air coupling windows are arranged on the splicing surface to realize coupling between the two cavities. The transmission zero can be formed at the low end of the pass band of the filter, and the rectangular coefficient of the filter is increased, thereby improving the filter performance and reducing the volume of the filter.

The invention discloses a large-power air coupling ultrasonic vibration transducer which comprises a bolt, a back shroud, a piezoelectric ceramic piece, an electrode piece, an amplitude transformer, a conversion sleeve, a vibrating plate and a coupling layer, wherein the coupling layer is stuck to the vibrating plate. The back shroud, the piezoelectric ceramic piece, the electrode piece and the amplitude transformer are sleeved on the bolt in sequence, the back shroud and the amplitude transformer clamp the piezoelectric ceramic piece and the electrode piece tightly through the bolt, the conversion sleeve is arranged at the front end of the amplitude transformer, and the vibrating plate and the coupling layer which is stuck to the vibrating plate are arranged at the front end of the conversion sleeve. The large-power air coupling ultrasonic vibration transducer uses a sandwich type piezoelectric transducer structure and has the advantages of being large in power capacity, high in sound field output strength and the like. The large-power air coupling ultrasonic vibration transducer can be applied to the fields of ultrasonic defoaming, ultrasonic suspension, ultrasonic medical treatment, ultrasonic dedusting, ultrasonic drying, ultrasonic gas medium sound field focusing, multi-phase sound field focusing, ultrasonic coagulation, ultrasonic nondestructive testing and the like.

The invention discloses an air coupling Lamb wave nonlinear ultrasonic stress detection method, system and device for a fiber reinforced composite material, and belongs to the field of ultrasonic stress detection. Traditional nonlinear ultrasonic stress detection has system errors, and special fiber material stress detection causes damage to the structure and performance of a material. The air coupling Lamb wave nonlinear ultrasonic stress detection method comprises: obtaining a pure Lamb wave mode by processing a to-be-detected fiber reinforced composite material, and the pure Lamb wave comprising a symmetric mode S0 and an antisymmetric mode A0; determining an antisymmetric mode A0 group velocity according to the frequency dispersion curve, and carrying out air coupling ultrasonic detection according to the antisymmetric mode A0; performing air coupling ultrasonic detection on the to-be-detected fiber reinforced composite material to obtain a relative nonlinear coefficient of the to-be-detected fiber reinforced composite material sample, namely obtaining the to-be-detected fiber reinforced composite material sample to realize stress characterization. According to the invention, the influence of a coupling agent is eliminated, the flexibility of stress detection of the fiber reinforced composite material is enhanced, and the detection efficiency is improved.

A broadband acoustic lens and method of designing same is provided for focusing an incident acoustic wave. The broadband lens includes a plurality of concentric rings, where each concentric ring of the plurality of concentric rings has a ring width, and a plurality of gaps, where each gap of the plurality of gaps has a spacing. The concentric rings are separated by a spacing corresponding to a gap of the plurality of gaps. The widths of the plurality of concentric rings and the spacings of the plurality of gaps are arranged such that the incident acoustic wave is focused to a spot within a sub-wavelength of the incident acoustic wave in air. The arrangement of the widths of the plurality of concentric rings and spacings of the plurality of gaps is aperiodic.