"29245" . . . . . "RIV/00216305:26220/14:PU111425!RIV15-MSM-26220___" . "Cs\u00E9falvay, Gabriel" . "465" . "Microstructure and Defects Evaluation of Varistors by Ultrasonic Waves in Low Frequency Range" . "4"^^ . . "Each material contains defects and in-homogeneities in a structure volume. It has influence on the properties of material (conductivity, mass density, mechanical properties). Interaction of the ultrasonic waves with defects or in-homogeneities in the solid state is not clear. Electro-ultrasonic spectroscopy can help to clarify this phenomenon. The electro-ultrasonic spectroscopy describes defects and un-homogeneities inside the sample structure. This method is quite different from electro-acoustic effect. Ultrasonic signal is in range from 20 kHz to 150 kHz. Ultrasonic signal changes geometry of the sample in elastic range only. The sizes of cracks are changing also in the sample volume. Conductivity near the area of cracks is strongly changing due to ultrasonic vibrations. It has influence on resistance of the sample which is changing along with a frequency of ultrasonic vibrations. The amplitude of the resistance change depends on the material, number of cracks, size of cracks and Eigen frequencies"@en . . . . "Microstructure and Defects Evaluation of Varistors by Ultrasonic Waves in Low Frequency Range" . "RIV/00216305:26220/14:PU111425" . "26220" . . "Microstructure and Defects Evaluation of Varistors by Ultrasonic Waves in Low Frequency Range"@en . . "4"^^ . . "CH - \u0160v\u00FDcarsk\u00E1 konfederace" . "Non-destructive testing, electro-ultrasonic spectroscopy, resistance change, crack geometry change, inhomogeneities"@en . "P(ED1.1.00/02.0068), P(ED2.1.00/03.0072)" . . "\u0160karvada, Pavel" . . . "Tofel, Pavel" . "[287E9A38C74E]" . "Each material contains defects and in-homogeneities in a structure volume. It has influence on the properties of material (conductivity, mass density, mechanical properties). Interaction of the ultrasonic waves with defects or in-homogeneities in the solid state is not clear. Electro-ultrasonic spectroscopy can help to clarify this phenomenon. The electro-ultrasonic spectroscopy describes defects and un-homogeneities inside the sample structure. This method is quite different from electro-acoustic effect. Ultrasonic signal is in range from 20 kHz to 150 kHz. Ultrasonic signal changes geometry of the sample in elastic range only. The sizes of cracks are changing also in the sample volume. Conductivity near the area of cracks is strongly changing due to ultrasonic vibrations. It has influence on resistance of the sample which is changing along with a frequency of ultrasonic vibrations. The amplitude of the resistance change depends on the material, number of cracks, size of cracks and Eigen frequencies" . "1013-9826" . . "4"^^ . . "Key Engineering Materials (print)" . "Cs\u00E9falvay, Gabriel" . . . "Microstructure and Defects Evaluation of Varistors by Ultrasonic Waves in Low Frequency Range"@en . . "1" . . "\u0160ikula, Josef" .