Abstract: The features of the present invention are 1) to apply metallization on the bonding surface of a piezoelectric ceramic with a metal likely to react with the piezoelectric ceramic material, 2) when the piezoelectric ceramic material is soldered on the bonding surface, to apply metallization with a metal likely to react with the solder material, 3) to provide between the metallizing layers formed in 1) and 2) a metallizing layer including metal which prevents reaction between the metals and their diffusion, 4) to use a mounting member for the piezoelectric ceramic which has substantially the same thermal expansion coefficient as the piezoelectric ceramic in non-polarization condition and 5) to solder in the non-polarization condition and thereafter to polarize.

Abstract: A method and apparatus for monitoring cracks of a rotatable body by detecting cracks by measuring accoustic emission signals and evaluating the depth of cracks from the result of the comparison of assumed vibrations of the rotatable body and its measured vibrations. By this method and apparatus not only the beginning of cracking of the rotatable body, but also the progress of cracking on an online basis can be detected and monitored.

Abstract: Disclosed is a rotating machinery diagnosis system with an AE technique, which comprises: an AE sensor mounted on a rotary machine for sensing an acoustic signal of the rotary machine; envelope detector means for obtaining an envelope signal from the acoustic signal from the AE sensor; waveform-feature processor means for performing signal processing so as to detect a feature of waveform of an output waveform signal from the envelope detector means; feature decision means for judging whether the feature of waveform belongs to a continuous type or a burst type and/or to a rotation-synchronous type or a rotation-asynchronous type on the basis of an output signal from the waveform-feature processor means; and diagnostic output means for outputting and displaying an output signal from the feature decision means, whereby it is possible to perform judgement simultaneously as to a plurality of kinds of abnormality.

Abstract: A tablet type coordinate input apparatus comprises a flat medium for propagating a longitudinal elastic wave, longitudinal elastic wave detecting elements disposed on part of the end-adjacent side surfaces or of the front surface of the flat medium, a longitudinal elastic wave input member having an end portion terminating in a sharp-pointed end and brought into pressure engagement at that end with any desired position on the surface of the flat medium to radiate the longitudinal elastic wave from that end, an amplifier circuit amplifying electrical signals indicative of the elastic wave detected by the detecting elements, a comparator circuit comparing the signals amplified by the amplifier circuit with a predetermined threshold voltage thereby generating delay pulse signals corresponding to the propagation times of the longitudinal elastic wave, a counter circuit counting the lengths of time elapsed from the time of radiation of the longitudinal elastic wave toward the flat medium as a result of pressure en

Abstract: A method and apparatus for detecting the occurrence of rubbing in a rotary machine, in which at least one acoustic sensor is mounted on at least the rotor part or the stator part of the rotary machine, and the output signal from the acoustic sensor is detected and then filtered to extract a frequency component having a frequency substantially equal to the rotational frequency of the rotary machine, so as to detect the occurrence of rubbing in the rotary machine as early as possible and also to locate the source of the rubbing. Even when the occurrence of abnormal metal-to-metal contact at a bearing of the rotary machine is detected, it is discriminated from rubbing so that the occurrence of the rubbing can be reliably detected.

Abstract: An electromagnetic-acoustic measuring apparatus is disclosed in which an exciting coil is wound around a body to be inspected in order to generate a magnetic field within the body in the direction parallel to a surface of the body, a transmitting coil is used to generate mechanical strain in the surface of the body by utilizing the magnetic field, a receiving coil detects the mechanical strain at the surface of the body after the mechanical strain has been propagated in the body, the exciting coil is enclosed with a separable core, the transmitting and receiving coils are supported by respective head portions of pole pieces fixed to the core, and the transmitting and receiving coils and pole pieces are water-cooled by means of cooling pipes.

Abstract: First and second magnetic poles are provided, which have end surfaces brought close and in opposition to a material to be examined. These magnetic poles are magnetized by a DC exciter coil such that the magnetic poles have opposite polarities. The first magnetic pole is provided at its end surface with a pair of cumulatively connected transmitting coils, and the second magnetic pole is provided at its end surface with a pair of differentially connected receiving coils. The transmitting coils are connected to a pulser which generates a pulse current, and the receiving coils are connected to a differential amplifier. An electromagnetic ultrasonic wave generated by the transmitting coils are received by the receiving coils, amplified by the differential amplifier, and thereafter supplied to a synchroscope and an automatic detector.