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TRANSMISSION OF SOUND THROUGH THIN PLATES |
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Canadian Journal of Research,
Volume 17a,
Issue 9,
1939,
Page 179-193
F. H. Sanders,
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摘要:
The transmission of high frequency sound through plates of brass and nickel has been studied for angles of incidence ranging from 0 to 70 degrees, using effective plate thicknesses varying from one-twentieth of a wave-length to one wave-length. In addition to strong transmissions in the region below the normal critical angle, very sharp and intense transmission maxima are observed at angles of incidence greatly in excess of the critical angle. These transmission maxima fall within three clearly denned angular regions: (i) angles between zero and the critical angle for longitudinal waves; (ii) angles between the critical angle for longitudinal waves and the critical angle for transverse waves; and (iii) angles above the critical angle for transverse waves. In Regions (i) and (ii) the observed data are in satisfactory agreement with a recent theory advanced by Reissner, and good values of the elastic constants are obtained. By an extension of Lamb's theory for flexural vibrations in bars the results in Region (iii) can be interpreted.
ISSN:1923-4287
DOI:10.1139/cjr39a-015
出版商:NRC Research Press
年代:1939
数据来源: NRC
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2. |
AN APPARATUS FOR THE DETECTION OF MAGNETIC MATERIALS |
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Canadian Journal of Research,
Volume 17a,
Issue 9,
1939,
Page 194-195
J. S. Johnson,
G. S. Field,
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PDF (94KB)
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摘要:
An apparatus for the detection of magnetic materials is described which operates on continuous direct current instead of alternating current or interrupted direct current, as has been the case with previous detectors. This apparatus is highly sensitive and requires very little adjustment. Once installed it can be operated by a non-technician.
ISSN:1923-4287
DOI:10.1139/cjr39a-016
出版商:NRC Research Press
年代:1939
数据来源: NRC
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