ISSN:0001-4966    

DOI:10.1121/1.1915923

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915924

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

The paper presents an experimental and theoretical discussion of acoustic signaling between a sending station and a receiving station near a plane reflecting surface, and is applicable to fog horn and submarine signaling. The experiments were made with a small scale apparatus employing supersonic waves of a frequency of 67.5 kilocyles per second. It is shown that at grazing incidence the direct and reflected waves cancel, or partially cancel, as predicted by theory. The cancelation for propagation in air near a water surface, or other surface of high sound velocity and high density, is found to be restricted to angles very near to grazing incidence. On the other hand, theory predicts cancelation for much larger departures from grazing incidence if the reflecting surface has high density but low velocity; experimental curves for transmission over beach sand and certain other substances resemble such theoretical results very closely. Acoustic mirages caused by temperature gradients were studied experimentally, and their effects are shown to be of striking importance in modifying the above results.

ISSN:0001-4966    

DOI:10.1121/1.1915925

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915926

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

Correlation of extensive results obtained from Y‐cut plates with those obtained from X‐cut and other plates leads to the conclusion that some thickness vibrations may produce a considerable acoustical effect while their electrical effect may be absent or at least difficult to detect by ordinary methods. The cause of this condition is thought to be the relatively strong electrical effect of the shear vibration or of certain length vibrations (harmonics) that happen to be quite near the mechanical thickness frequency responsible for the detected sound waves. Obviously the latter is more effective in producing sound waves traveling normal to the plate. The effect of humidity on the wave velocity was also studied. Two dispersion regions in air were discovered.

ISSN:0001-4966    

DOI:10.1121/1.1915927

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915928

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915929

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915930

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915931

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915932

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP