| Autor: |
Yapura, Carlos L., Kinra, Vikram K., Maslov, Konstantin |
| Předmět: |
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| Zdroj: |
Journal of the Acoustical Society of America; Jan2004, Vol. 115 Issue 1, p57-65, 9p, 1 Diagram, 4 Charts, 8 Graphs |
| Abstrakt: |
An ultrasonic technique for a simultaneous determination of traveling times and acoustic impedances of three-layered, platelike specimens using a normally incident longitudinal wave is presented. The acoustical properties are determined by minimizing the difference between measured and calculated resonant frequencies in the well-known least-squares sense. The resonant frequencies of the layered structure are deduced, in transmission, from the maxima of the magnitude of the transmission spectrum, or, in reflection, from the π values of the phase of the reflection spectrum. Measurements are carried out in the frequency range 1-20 MHz for teel/aluminum/steel and silver/copper/nickel specimens with individual layer thickness values ranging from 0.3 mm to 2 mm. The differences between the inverted thicknesses and those measured directly with an optical microscope range from -4 mm to +13 µm. Estimated error bounds suggest that the inverted travel times are accurate within ± ns with 95% probability. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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