Mechanical and electrical properties of nanocomposite materials composed of a SiJN4 matrix and nanometer-sized Sic particles are described. Composites containing less than 10 vol% Sic particles have the same order of resistivity and dielectricity as the non-Sic material as well as highly improved mechanical properties. The composites are promising materials for use under harsh conditions. [

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A system for measuring the sound velocity in a liquid is described, which uses an interdigital transducer (IDT) for a leaky surface acoustic wave. The IDT on a piezoelectric substrate effectively operates as a radiator and a detector of the bulk wave at a liquid-solid interface. The measurement is accomplished by a frequency sweeping method under the condition of the fixed sound path length. The output curve is obtained as a function of the frequency at the IDT in the form of the interference between the input and the output signal reflected from the reflector. The measurement resolution of the present system is within 0.1%.

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A system for measuring sound velocity in liquid is constructed using an interdigital transducer for leaky Lamb waves on a 128° rot. Y-X cut LiNbO3 substrate. The leaky Lamb wave device is composed of a 1-mm-periodicity interdigital transducer and a counter electrode on each surface of the 0.5-mm-thick piezoelectric substrate. The device is operable for 8 modes in the frequency range of 2∼25 MHz at a water-solid interface. The measurement principle of this system uses the interference between a rf pulse signal and a reflected signal. The system successfully measures the absolute sound velocity in some liquid samples. The measurement resolution of the system is within 0.1%.