Abstract: Material analysis apparatus and method, particularly of use in detecting barely visible impact damage but also of use to detect other material characteristics. The apparatus includes a function generator (15) which provides a sinusoidal signal to an ultrasonic amplifier (14) as well as to a PC (16). The PC is connected to an infrared camera (17). The sinusoidal signal is fed into the amplifier and causes two probes (12, 13) attached to the sample of material to emit ultrasonic energy at the modulated frequency. Ultrasonic energy from the two probes then enters the sample (11) by means of a mechanical coupling and an image of the resulting thermal radiation is captured by the infrared camera and transferred to the PC for further processing and analysis.

Abstract: The present invention discloses a method and device for imaging based on the electroacoustic effect. The electroacoustic effect takes place when an ultrasonic wave passes through an electrolyte or colloidal suspension. The method and device of the present invention produces images whereby a sound wave is generated at the surface of an object, and, as the wave progresses through the body a voltage is generated in time corresponding to the electroacoustic response of the body at a point in space and time corresponding to the position of the ultrasonic wave in the body. As pulses are launched into the body at different points in space, the signal sensed by an amplifier is used to generate an image.

Abstract: The present invention relates to an adaptive transmit-focusing and a beam-forming method and apparatus. The present invention in connection with beam-forming applies adaptive patterns of delay profiles to reflected ultrasonic pulses from a group of ultrasonic pulses, received by transducer arrays, forms multiple sets of preliminary scan-line data and combines the multiple sets of preliminary scan-line data into single scan-line data. The present invention in connection with transmit-focusing performs focusing a group of ultrasonic pulses by applying a plurality of delay profiles in accordance with propagation velocities within an object region to be ultrasonic imaged. The present invention reduces transmit-focusing and beam-forming errors generated from applying a single pattern of delay profile, and provides clear ultrasonic images.

Abstract: A method and system for determining material properties of a cross-section of an anisotropic sample material. An ultrasonic signal is applied to the surface of the anisotropic sample material, which comprises multiple constituent material layers, such that a characteristic medium wave is induced within each of the constituent materials. Each of these characteristic medium waves is sampled over a time interval to obtain a test waveform. This resultant test waveform is then spectrum analyzed utilizing cepstrum noise filtration, such that the material properties of said anisotropic sample material may be determined.

Abstract: An ultrasonic inspection method for determining acceptability of material for microstructurally sensitive applications comprises providing a material, directing ultrasonic energy of ultrasonic inspection to the material; scattering reflected energy in the material; determining an amount of noise generated by the ultrasonic inspection; and characterizing the material as acceptable if the amount of noise corresponds to a pre-determined noise level. The invention also sets forth a system for implementing the method, as embodied by the invention.

Abstract: An ultrasonic microscope for acquiring data from internal regions of a sample body is provided. The ultrasonic microscope includes an ultrasonic transmitter for providing a point source of ultrasonic waves for input-coupling into a sample body at a point in proportion to the dimensions of the sample body. Ultrasonically-induced excursions of a receiving tip can be detected with atomic resolution by using an ultrasonic detector that measures with high sensitivity resolution. The ultrasonic transmitter and the ultrasonic detector may be positioned relative to one another such that the ultrasonic detector can adopt several receiving positions for each transmitting position of the ultrasonic transmitter. A measurement data signal from the ultrasonic detector is stored and processed in a central processor. An image generator within the central processor uses a tomographic algorithm to reconstruct an image of at least one area inside the sample body from the measurement data.

Abstract: The present invention discloses a method and apparatus for ultrasound imaging with improved spatial sampling. The device includes a plurality of ultrasound imaging elements each having a pitch defined by the center to center spacing of the ultrasound imaging elements; and a motion mechanism operatively connected to the plurality of ultrasound imaging elements and adapted to move the plurality of ultrasound imaging elements over a distance to increase the spatial sampling of the plurality of ultrasound imaging elements. The method of the present invention includes transducing a signal from one or multiple ultrasound imaging elements within an array of ultrasound imaging elements; moving the array of ultrasound imaging elements a distance less than the pitch; and transducing at least one additional signal from the ultrasound imaging element.

Abstract: The present invention provides a mounting assembly, for use with an ultrasound transducer attached to an ultrasound machine, for determining the spacial relationship between a succession of 2D image slices of a target of a subject, generated by the ultrasound machine. The mounting assembly comprises: (i) means to mount an ultrasound transducer; (ii) means to engage a surface of the subject in the proximity of the target, the means to engage a surface being moveably attached to the means to mount an ultrasound transducer; and (iii) sensing means, in communication with the means to engage a surface, to measure the movement of the means to engage a surface during acquisition of the succession of 2D image slices. Preferably, the sensing means comprises a tilt sensor and a displacement sensor.

Abstract: An ultrasonic diagnostic apparatus wherein a three dimensional space is scanned by ultrasonic beams and echo signals are received simultaneously in parallel to produce ultrasonic information. During operation, transmitting/receiving conditions are selected from a plurality of transmitting/receiving conditions. Operation is then switched at a predetermined period between the selected transmitting/receiving conditions so that the three dimensional space is scanned by ultrasonic beams and echo signals are alternately received, at the predetermined period, under the selected transmitting/receiving conditions. Image information for each selected transmitting/receiving condition is obtained and respective ultrasonic images corresponding to each transmitting/receiving condition are simultaneously displayed.

Abstract: A novel method of non-destructive die crack inspection of a plastic encapsulated integrated circuit (PEIC) uses a scanning acoustic microscope, such as a C-mode scanning acoustic microscope. To generate scan of a die surface of the PEIC, the width of a data gate of the microscope is set to scan only the die surface. Then, the data gate is moved to cover only die subsurface reflection area on a screen of the microscope, and scan of the die subsurface is generated.

Abstract: An ultrasound imaging method forms an image of an object using signals reflected from the object after transmitting an ultrasound pulse to the object. In the method, at a first step, a predetermined first spread spectrum signal is converted to the ultrasound signal at one or more transducers and the ultrasound signal is transmitted to the object. At a second step, pulse compression is performed on a reflected signal of the ultrasound signal reflected from the object to form a pulse compressed signal. And the pulse compressed signal is processed to produce a receive-focused signal and the image of the object from the receive-focused signal is generated.

Abstract: An electronic scanning ultrasonic object-detection apparatus 1 of the present invention comprises; phase control signal generation means 2 for generating a plurality of phase control signals having different transmission frequencies; ultrasonic wave transmission means 3 for transmitting ultrasonic waves of a transmission frequency different from each other by a plurality of arrays, based on the plurality of phase control signals; ultrasonic wave receiving means 4 for receiving reflected waves from an object of the ultrasonic waves with a plurality of receiving elements, judging a signal of the reflected waves received by all the receiving elements as a mail image to thereby output a mail image signal, and judging signals of other reflected waves as side images to thereby output a side image signal; and object-detection means 5 for detecting a position of an object based on the mail image signal output by the ultrasonic wave receiving means 4, and detecting existence of a side image based on the side image sig

Abstract: An ultrasound system determines the relative movement in a first direction (F1) of first matter, such as blood flow, and second matter, such as an artery wall, in a subject under study (S). A beam (B1) of ultrasound waves defining a plurality of beam positions (BP1 and BP2) and beam axes (A1and A2) are moved in scan directions having components parallel to direction F1. First and second blocks of data representing the first and second matter, respectively, are generated. A processor (20) performs an estimation of speckle size on first data to obtain a first result, and performs analysis of the second block of data to obtain a second result. The two results are analyzed to obtain a measure of the relative movement of the first and second matter.

Abstract: This invention relates to a method and apparatus for imaging acoustic fields in high-frequency acoustic resonators. More particularly, the invention is directed to a scanning RF mode microscope system that detects and monitors vibration of high frequency resonators that vibrate in the frequency range of approximately 1 MHz to 20 GHz. The system then maps with sub-Angstrom resolution vibration modes of such devices and obtains quantitative measurements of the piezoelectric properties of the materials.

Abstract: The present invention relates to a method and apparatus for focusing ultrasonic waves that are propagated from a phased array toward a spherically-bounded object so that they arrive at a pre-selected focal point at the same time and in phase and thereby significantly improve, nondestructively, the detectability of possible flaws in and structural characteristics of the object. The disclosed method comprises calculating the location of a plurality of preferred refraction points on a surface of the spherical work piece using an iterative process. Each of the preferred refraction points correspond to one of the elements of the phased array mechanism. The locations of the preferred refraction points depends upon the location of the pre-selected focal point and the locations of the phase elements.

Abstract: Method and apparatus using bending wave vibration to calculate information relating to a contact on a contact sensitive device. The contact sensitive device has a member capable of supporting bending waves, and a device attached to the member measures bending wave propagation in the member to determine a measured bending wave signal. The measured bending wave signal is processed to calculate information relating to the contact. The contact sensitive device may comprise a transparent touch sensitive plate mounted in front of a display device. A stylus (e.g., pen) may be used for writing text or other matter on the touch-sensitive plate. The plate may also be an acoustic device. Three transducers are mounted on the plate. At least two of the transducers are sensing transducers and are thus sensitive to and monitor bending wave vibration in the plate.

Abstract: A method and apparatus for nondestructive inspection of packaged integrated circuits and defect detection in the integrated circuits. In a scanning acoustic microscopy system, a packaged integrated circuit under test 31 is placed in a tank containing an acoustic transmission medium such as de-ionized water. An acoustic reflector 29 is placed beneath the integrated circuit 31. A pulse-echo mode transducer 17 is used to scan the area containing the integrated circuit 31 with ultrasonic energy. The reflective signal energy is captured by the transducer 17 and the signals are digitized and stored. A computer system analyzes the reflective signal amplitude, and presents a visual image based on where the reflective signal was strong and where it was weak. In a preferred embodiment the image is presented so that the signal from the reflective plate is shown as a dark region where the reflection was weak or zero.

Abstract: An acoustic microscope system is provided for analyzing the properties of a olid sample with fluid coupling. The system includes a transducer comprising a curved active piezoelectric element and an insulating backing member having a curved surface on which the piezoelectric element is mounted, a casing for backing member, and electrical input/output leads connected to the piezoelectric element. A pulser receiver, connected to the leads of the transducer, generates coherent test pulses of short duration and receives echoes from the solid sample resulting from these pulses and having a received echo waveform comprising multiple arrivals including direct reflection from the interface between the fluid and the solid sample. A wave recorder records the received echo waveform so as to enable the determination therefrom of information relating to the characteristics of the solid sample.

Abstract: The laser optoacoustic imaging system described herein utilizes time-resolved measurement of profiles of laser-induced transient pressure (acoustic) waves. The pressure waves are emitted by acoustic sources preferentially generated in absorbing tissues of diagnostic interest. This technique allows visualization of absorbed light distribution in turbid, layered and heterogeneous tissues irradiated by laser pulses in vivo. The laser optoacoustic tomography can be used for the characterization of structure and properties of normal tissue, and for the detection of tissue pathological changes. The optical heterogeneities that can be imaged with the laser optoacoustic imaging system include abnormal tissues such as tumors, injured tissues, blood vessels and other layered tissues. Further, three dimensional images of organs and portions of organs can be obtained.

Abstract: A non-destructive method of identifying a type of compound in a sample using an acoustic microscope, particularly, identifying the type of compound used in an integrated circuit package by comparing attributes of the tested molding compound with known attributes of known compounds to identify the compound being evaluated. The attributes that are compared include voltage, attenuation, peak frequency, average frequency, and the velocity of reflected sound.

Abstract: An apparatus and method are disclosed for producing acoustical reflected images from selected planes within an integrated circuit package to detect flaws within the package.

Abstract: A non-destructive method of identifying a type of molding compound in a sample using an acoustic microscope, particularly, identifying the type of molding compound used in an integrated circuit package by comparing attributes of the tested molding compound with known attributes of standard molding compounds to identify the molding compound being evaluated. The attributes that are compared include voltage, attenuation, peak frequency, average frequency, and the velocity of reflected sound.

Abstract: A display system for non-destructive inspection of integrated circuit packages is disclosed for producing acoustical reflected images from selected planes within an integrated circuit package to detect flaws within the package.

Abstract: An acousto-optic damage detector and locator uses acoustic energy propagated through a structure to modulate light transmitted through an optical fiber whereby the character of acoustic signals detected by the fiber varies according to the physical condition of the portion of the structure through which the pulses propagate to determine the existence, location and extent of faults within the structure.

Abstract: A method and equipment are described for performing measurements while drilling for oil or gas, in particular VSP-measurements employing a seismic source together with sensors such as hydrophones and/or geophones connected to a memory- and calculation device for storing and processing the seismic signals. The seismic source (2) is placed at or in the vicinity of the surface of the earth whereby signals generated by the source are detected by the hydrophones (3,5) or the geophones located in the vicinity of the source (2) at the surface and in the drill string (4). The geophones or the hydrophones (5) in the drill string transmit the detected signals to a memory- and calculation unit (6) in the drill string that processes and transmits the signals completely or partly to a central data processing unit (10) on the rig (7).

Abstract: A device for identifying fingerprints by use of ultrasound having an electronic evaluating circuit, a hollow cylinder of length L with a cover and a base plate, wherein the ultrasonic speed through the liquid equals c' and the cover is made from a material with ultrasonic speed c". The outer side of the cover is planar to serve as a supporting surface for the fingerprint. The inner side is either convex (c'>c') or concave (c'<c") with a spherical radius R and the condition L=R/.vertline.(c"/c')-1.vertline. must be satisfied. The individual ultrasonic receiver is arranged in the center of the base plate and extends over the smallest possible surface area. At least one annular transmitter is arranged concentrically around the individual ultrasonic receiver.

Abstract: Ultrasonic wave converged by an acoustic lens is made incident onto a sample and wave reflected from the sample is received and converted into received electric signal by a transducer. A part of this electric signal is picked up by a gate section and the signal thus picked up is applied to an attenuator where it is converted into a variable ratio of input to output. The strength of the signal thus gain-adjusted is compared with a threshold value by a comparator. Responsive to the comparison result thus obtained, the gain of the attenuator is adjusted to make the input/output ratio of the attenuator a desired value. A computer calculates the focus position of the acoustic lens from a gain curve of the attenuator changing when the acoustic lens is moved from a position, remote enough from its focus position, to the sample. Drivel signal responsive to the result thus calculated is applied to a Z-drive control section.

Abstract: A process and apparatus for visualization of internal stresses in solid mrials by an acoustic microscope (10) connected to an (5) having a circular or spherical transmitting and receiving surface (8) for transmitting ultrasonic waves to and receiving reflected waves from a sample (3) to be examined in a body of liquid (2), such as water, a motor drive unit (7) having a movable arm thereon (6) connected to the acoustic lens (5) for supporting and moving the for scanning the sample, the motor drive (7) being connected to the (10) for being operated thereby to perform the scanning, a computer (16) having a visual display unit (18), and an oscilloscope (20) for indicating the reflected waves.

Abstract: A high speed method for presenting display of images obtained from a volumetric scanner in which multiple slices of object space are displayed simultaneously in real time thereby enabling a viewer to study relationships between various parts of the object. The slices are selectable by the viewer manipulating an icon on the display screen. Accordingly C-scans or B scans may be selected as well as I scans in which the scan plane has a selected orientation. Multiple I scans may be selected and viewed in perspective so that the viewer has an impression of a three dimensional display. Color and spectral doppler is incorporated with the scans to provide additional information of dynamic properties.

Abstract: In an ultrasonic microscope apparatus, an ultrasonic pulse transmitter-receiver emits an ultrasonic wave irradiated on a sample, receives an echo from the sample, and emits an electric output signal in accordance with the received echo. A scanner is provided for scanning the sample by relatively moving the ultrasonic pulse transmitter/receiver and the sample, and, a detection circuit is provided for detecting an echo component included in the output signal from the ultrasonic pulse transmitter-receiver and for emitting a detected signal. A picture quality adjuster receives the detected signal, adjusts brightness and contrast of the detected signal, and outputs the adjusted signal as an image signal. An adjustment controller adjusts the adjustment amount of brightness and contrast in the picture quality adjuster in accordance with the brightness and contrast values of the image signal output from the picture quality adjuster.

Abstract: An acoustic lens system is constructed so that at least one surface of acoustic lenses constituting the acoustic lens system is an aspherical surface, which has such a shape that curvature moderates progressively in separating from the axis of the acoustic lens system, and an acoustic beam stop is provided therein. As a result, aberrations can be favorably corrected even when the angle of view and the numerical aperture are increased and this brings about the acoustic lens system suitable for an objective lens of an acoustic system for securing an image of an object having a two-dimensional size in particular.

Abstract: The present invention is a means and method for identification and recognition of an item by ultrasonic imaging of material microfeatures and/or macrofeatures within the bulk volume of a material. The invention is based upon ultrasonic interrogation and imaging of material microfeatures within the body of material by accepting only reflected ultrasonic energy from a preselected plane or volume within the material. An initial interrogation produces an identification reference. Subsequent new scans are statistically compared to the identification reference for making a match/non-match decision.

Abstract: An apparatus and method for non-destructive examination of an interface within a body between two separate elements of the body wherein an acoustic microscope (124) has an ultrasonic transmitter (114) for directing ultrasonic waves at an angle to a body (1) and an interface (122) within the body between an outer part (3) and an inner part (2), an acoustic receiver (116) in spaced relationship to the transmitter (114) for receiving acoustic leaky waves from the interface (122), and a supporting device for supporting the transmitter and receiver for simultaneous scanning movement relative to the body at the same scanning speed. The body to be examined may be supported immersed in a liquid such as water (120) in a tank (121) so that the ultrasonic waves from the transmitter are directed at a predetermined angle depending on the materials of the separate elements and-pass through the liquid and the outer part before impinging on the interface in the body to be examined.

Abstract: An ultrasonic sensor for use in an ultrasonic micro spectrometer includes a concave surface transducer having a concave ultrasonic wave transmitting/receiving surface and a plane transducer having a plane transmitting/receiving surface. The concave surface transducer is capable of transmitting converging ultrasonic waves toward a specimen, wherein the waves are reflected from the surface of the specimen and are received by the plane transducer which outputs electric signals corresponding to the intensity of the reflected ultrasonic waves. Based on a signal output from the ultrasonic sensor, a digital oscilloscope and FFT analyzer forms a distribution of spectral intensity indicating the intensity of the reflected wave as a function of frequency. The digital oscilloscope and FFT analyzer further forms a distribution of spectral phase indicating the spectral phase of the reflected waves as a function of frequency.

Abstract: A method of measuring thin film properties of materials using interference of ultrasonic waves in the frequency range of 2-15 MHz. An ultrasonic interferometer produces interference "fringes" from which the film thickness can be accurately determined. The film may consist of any solid material having known sonic properties and thickness of the order of the sonic wavelength. The device utilizes a narrow-band source of ultrasound and guided-wave propagation to accurately define the optical path of the ultrasonic waves producing the interference. The interferometer is also useful to measure certain material properties in thin specimens, thereby allowing the material to be characterized locally.

Abstract: The ultrasonic sound velocity measuring apparatus or ultrasonic microscope moves the sample to be measured or examined relative to a focusing acoustic probe from its focal point to a defocus point closer to the probe; subjects the intensity of a first reception signal in the peripheral portion of the transducer of the acoustic probe as obtained therefrom in response to said relative movement of the sample, the phase difference between the first reception signal and either the signal for driving the acoustic probe or the corresponding reference signal, the intensity of a second reception signal in the central portion of the transducer of the acoustic probe as obtained therefrom in response to said relative movement of the sample, and the phase difference between the second reception signal, and either the signal for driving the acoustic probe or the corresponding reference signal to more than one sampling at time intervals corresponding to positions in the defocus direction; and obtains data on the intensity a

Abstract: An acoustic lens system is constructed so that at least one surface of acoustic lenses constituting the acoustic lens system is an aspherical surface, which has such a shape that curvature moderates progressively in separating from the axis of the acoustic lens system, and an acoustic beam stop is provided therein. As a result, aberrations can be favorable corrected even when the angle of view and the numerical aperture are increased and this brings about the acoustic lens system suitable for an objective lens of an acoustic system for securing an image of an object having a two-dimensional size in particular.

Abstract: An acoustic microscope assembly for atomic level inspection of a target object includes a cantilever arm with a sharp tip on its lower surface and a zinc oxide piezoelectric thin film on its upper surface. High frequency excitation signals, having a frequency of at least 50 Megahertz, are applied to the piezoelectric thin film so as to generate high frequency acoustic signals that are transmitted through the sharp tip so as to impact on a target object. The assembly can either receive acoustic signals reflected by the target object, or it can receive acoustic signals that have propagated through the target object. One method of using this assembly is to apply a continuous wave signal to the piezoelectric thin film while scanning the target object, and measuring characteristics of the target object at various positions thereof by measuring the resonant frequency of the transmitted high frequency acoustic signals.

Abstract: A process and apparatus for visualization of internal stresses in solid materials by an acoustic microscope (10) connected to an acoustic lens (5) having a circular or spherical transmitting and receiving surface (8) for transmitting ultrasonic waves to and receiving reflected waves from a sample (3) to be examined in a body of liquid (2), such as water, a motor drive unit (7) having a movable arm thereon (6) connected to the acoustic lens (5) for supporting and moving the lens for scanning the sample, the motor drive (7) being connected to the acoustic microscope (10) for being operated thereby to perform the scanning, a computer (16) having a visual display unit (18), and an oscilloscope (20) for indicating the reflected waves.

Abstract: Ultrasonic apparatus that automatically adjusts the focus of ultrasonic waves to a desired depth within an object includes an ultrasonic probe which irradiates a focused ultrasonic beam onto an object to be inspected and a receiver which receives ultrasonic waves reflected from the object. A desired focusing depth is set and the inherent focal length of the probe and the velocity of sound within the object are detected to evaluate a distance between the probe and the object at which the focus of the probe coincides with the desired depth. The distance between the probe and the object is adjusted to coincide with the evaluated distance.

Abstract: A method is provided for determining the wetting preference of particulate solids, for example sand, dispersed in a multiphase liquid medium having a continuous phase and a discontinuous phase, for example a water-in-oil emulsion. A dispersion of the particulate solids and the liquid medium is passed through an electroacoustical cell and the electroacoustical signal is measured for varying solids content. If the signal remains substantially constant this indicates a wetting preference for the continuous phase, whereas if the signal decreases this indicates a wetting preference for the discontinuous phase.

Abstract: Foreign materials in a chemical specimen are detected by irradiating the chemical specimen with ultrasonic waves and detecting and monitoring scattered sound from the foreign materials in the chemical specimen. Even if the foreign materials are photosensitive substances which cannot be exposed to light, they can be detected.

Abstract: A scanning acoustic microscope of the present invention comprises a high frequency transmitter for transmitting high frequency signal, first electric/ acoustic conversion element for converting the high frequency signal to ultrasound, acoustic lens having an end surface to which the ultrasound is incident and a concave lens surface to which the incident ultrasound is exited, an ultrasound receiver having a flat receiving surface located in an opposed relation to the concave lens surface to allow the transmission of only that ultrasound substantially vertically incident to the receiving surface, second electric/acoustic conversion element for converting ultrasound which has been transmitted through the ultrasound receiver to an electric signal, and an image processing circuit for preparing an image in accordance with a reception signal delivered from the second electric/acoustic conversion element.

Abstract: The present invention relates to an acoustic microscope system having an ultrasonic probe that is driven with a high-frequency burst signal to radiate an ultrasonic signal and that detects the resulting reflected and irradiated waves, a Z-axis moving device that updates the vertical distance Z between the probe and a material of interest for each sampling position, and device for constructing a V(z) curve from the reflection signals obtained at respective sampling positions. The ultrasonic probe of the invention is provided with an acoustic lens, a first ultrasonic transducer for receiving a leaky surface skimming compressional wave reflected from a sample material on one side of the acoustic lens, and a second ultrasonic transducer also provided on the side of the acoustic lens for receiving a leaky surface acoustic wave.

Abstract: The invention pertains generally to ultrasonic imaging systems and is more particularly directed to use of such systems for nondestructive testing to measure the thickness of parts, or to examine parts suspected of having internal flaws but where access is often limited to the external surfaces. The invention makes thickness and flaw determinations of substantial accuracy without resulting to use of an expensive ultra high frequency clock to measure time.

Abstract: An ultrasonic probe includes a housing, a piezoelectric element provided in the housing, the piezoelectric element emitting an ultrasonic beam, and a refracting member rotatably provided in the housing. The refracting member has a first surface opposite to the piezoelectric element and a second surface at which the ultrasonic beam emitted from the piezoelectric element and passing through the first surface is deflected in a state where a deflection angle between an axis perpendicular to a surface of the piezoelectric element and a deflected ultrasonic beam changes as the refracting member rotates.

Abstract: An ultrasonic microscope comprises an acoustic lens for emitting an ultrasonic beam, a movable shaft for supporting a sample, and a drive circuit for moving the movable shaft and thus the sample relative to the acoustic lens in a z-direction. Two signals for eliminating x-direction and y-direction inclinations of the sample relative to the acoustic lens are supplied to the drive circuit in synchronism with an x-direction drive signal and a y-direction drive signal, so that the sample is moved in the z-direction and scanned with the ultrasonic beam in an x-y direction while the sample inclination sample to the acoustic lens is being eliminated.

Abstract: The strength of a join between a ceramic and an associated non-ceramic is determined using an ultrasonic microscope. A converging ultrasonic beam is radiated against a point on a surface of the ceramic, said point being a predetermined distance away from the join between the ceramic and the associated non-ceramic. Data on the intensities of interference waves at respective predetermined variations of the relative distance between a probe of the ultrasonic microscope and the ceramic are collected. The residual stress at the point is calculated on the basis of the cycle of echo intensities of the interference waves for the respective predetermined variations of the relative distance. The strength of the join is then determined on the basis the residual stress.

Abstract: A high-frequency signal is applied from an oscillator via a circulator to a piezoelectric transducer. An ultrasonic wave generated by the piezoelectric transducer is directed to a material through an acoustic lens. The ultrasonic wave transmitted through the material is conducted to a phase-conjugator having a nonlinear piezoelectric element consisting of a crystal of LiNbO.sub.3. A phase-conjugate wave generated by the generating section is transmitted through the material again and received by the piezoelectric transducer. The received signal is supplied to a receiver circuit via the circulator. The receiver circuit gates the received signal in accordance with a time of return of the phase-conjugate wave so as to extract a signal representing the interior of the material. The material is scanned two-dimensionally by a scanning control device so as to display a two-dimensional ultrasonic image on a television monitor.

Abstract: A heat exchanger (4) for cooling a machine, such as a mechanical gear or some other transmission component, hydraulic pump, motor or clutch, compressor, internal combustion engine or like machine, which comprises a housing (1) in which movable, mechanical elements (2), which are driven when the machine is working, are housed, and which encloses a liquid medium (3), such as a lubricating or hydraulic liquid. The heat exchanger is mounted in the outer wall (5) of the housing and comprises two chambers (6, 7) which are mutually separated by a liquid-impervous partition wall (8) which comprises part of the housing wall. The inwardly located chamber (7) is through-passed by the liquid medium (3) enclosed in the housing, while the outwardly located chamber (6) is through-passed by a cooling medium.