摘要:

An experimental study has been made of the propagation of ultrasound in liquids under both free‐field and guided‐wave conditions. Free‐field measurements have been made from 1 to 20 Mc in low absorbing liquids, employing both circular and square sound sources. These measurements indicate that the correction for diffraction loss predicted by existing theories is applicable only so long as this loss is smaller than the true absorption. Attenuation measurements also have been made in liquids confined in various cylindrical and rectangular metallic waveguides. For a given configuration, the observed variation with path length of the attenuation follows closely that predicted theoretically for propagation in a solid sample of the same dimensions. Some consideration is given to possible sources of this result which differs somewhat from the predictions of current theories.

ISSN:0001-4966    

DOI:10.1121/1.1908458

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

A computer simulation program for visual “pattern recognition” has been tested on an array of extremely degraded spoken digits. The program develops its own set of operators, as a function of its experience with inputs presented to it; so it does not depend upon preanalysis of a specific problem. The program gave (on an array of five different numbers) 100% success on words that had been presented to it for “training” purposes, and 100% success on words spoken by speakers different from those used in training. Results with alphabetic patterns, in which 5‐, 10‐, and 26‐letter arrays were all learned to 100% success, suggest that larger arrays of spoken words may give similar results.

ISSN:0001-4966    

DOI:10.1121/1.1908460

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

The complex shear modulus of Hycar rubber has been determined from acoustical measurements, over a wide range of frequencies and temperatures. From these data and the density of the rubber, the speed of transverse waves has been computed. Results are compared with values inferred in a previous paper, when the rubber was used as the bottom material in a model‐scale test of shallow‐water propagation. Discrepancies are about 15%.

ISSN:0001-4966    

DOI:10.1121/1.1908462

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP

摘要:

A procedure is outlined for computing the remainder of Robey's Reactive Impedance Integral for the self and mutual impedance of rings on an infinitely long rigid cylindrical baffle. It is assumed that numerical integration has been carried out to a given point. The remainder of the infinite integral is then computed in terms of the well known sine and cosine integrals which have already been tabulated in the literature.

ISSN:0001-4966    

DOI:10.1121/1.1908466

出版商:Acoustical Society of America    

年代:1961

数据来源: AIP