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Volume 8 (1952)
- Issue 4 Pages 163-
- Issue 3 Pages 115-
- Issue 2 Pages 55-
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Volume 8, Issue 3
Displaying 1-9 of 9 articles from this issue
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[in Japanese]Article type: Article
1952 Volume 8 Issue 3 Pages 115-116
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSDownload PDF (307K) -
[in Japanese]Article type: Article
1952 Volume 8 Issue 3 Pages 117-122
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSDownload PDF (845K) -
Jun'ichi Saneyoshi, Kaoru NakamuraArticle type: Article
1952 Volume 8 Issue 3 Pages 123-127
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSWith respect to ultrasonic fish finding, a theory for calculation of reflecting power of fish school is developed. The reflecting power is defined by us as the ratio of the sound pressure of the reflected wave from the fish school at the position of the source to that from an infinte rigid plane situated at the position of the fish school. The calculation shows that the reflecting power is independent of the distance, and is proportional to the beam angle, the square root of the pulse length and the square root of the fish density, as far as the school extend beyond the beam angle. The model experiment is performed in air, utilizing many soft tennis balls suspenced in random distribution as the reflecting obstacles. The frequency and the wave length are 14. 2kc and 2. 4cm, respectively. The theorectical results written above are proved approximately. The absolute value of the reflecting power of fish school is also given theoretically, assuming the cause of reflection from a fish to be the air-bladders and the density difference of the fish body and the water. This was not experimentally verified in this work, and the reflecting power of a single fish is now under measurement in other laboratory for many kinds of fish.View full abstractDownload PDF (533K) -
Yasuo TorikaiArticle type: Article
1952 Volume 8 Issue 3 Pages 128-132
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSThe theoretical calculations on diffraction of light by superposed ultrasonic waves are shown and the intensity distributions on the diffraction plane of the optical system are definitely obtained. The calculations are separately performed on two cases of crosseed waves and parallel waves, and the resulting expressions, similar to each other, agree well with experimental and theoretical results by Bergmann and others. The results obtained can be directly applied to the calculation of the image formation of superposed ultrasonic waves, as shown in the next report.View full abstractDownload PDF (397K) -
Yasuo TorikaiArticle type: Article
1952 Volume 8 Issue 3 Pages 133-139
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSTheoretical calculations are performed on the image formations of superposed ultrasonic waves. Instead of the usual method developed by Hiedemann and others for visualizing ultrasonic waves, the more general phase method are applied to the visualization. In this method, the zeroth order diffraction image subjects a proper absorption and a phase retardation by the phase plate placed in the diffraction plane, instead of being perfectly screened. From the expressions for the image formation, the image shapes are obtained, and the relation between the visibility of the images and the characteristics of the phase plate is investigated. As to the image formation of surperposed ultrasonic waves, Willard discussed the case in his paper, "Improved Methods for Measuring Ultrasonic Velocity", but it is shown that appreciable errors occur from his simple consideration with the increase of sound intensity in comparison with the present exact theory. This matter will be experimentally verified in the next report.View full abstractDownload PDF (485K) -
Yasuo Torikai, Katsuo NegishiArticle type: Article
1952 Volume 8 Issue 3 Pages 139-142
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSExperimental procedure and results concerning the diffraction of light by superposed ultrasonic waves and image formation of the waves are described. The experimental apparatus used is not different from the usual ones. The results obtained are compared with the theoretical curves, showing the considerable agreements between them. Further, it is experimentally recognized that the image formation of superposed waves is effectively applied to the detection of weak ultrasonic waves and that problem is theoretically considered.View full abstractDownload PDF (611K) -
Tadamoto Nimura, Yoshiyuki WatanabeArticle type: Article
1952 Volume 8 Issue 3 Pages 143-148
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSA series of analysis for the zonal sound radiator was done. In the part I of these papers, the analysis for the zonal vibration of a prolate spheroid was developed by the use of prolate spheroidal wave functions. The directivity of radiated sound pressure and power, and radiation impedance was calculated. This analysis may be useful for the design of the public-address systems.View full abstractDownload PDF (422K) -
Tsuneji KoshikawaArticle type: Article
1952 Volume 8 Issue 3 Pages 149-153
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSThe microphone, picking up the sound pressure by some probe tube at any point in sound field or closed chamber, has been generally used. Here, the analysis on an example of such apparatus is presented, and the experimental result is compared with the analytical one.View full abstractDownload PDF (509K) -
Tanetoshi Miura, Zenji Yamaguchi, Akira Suzuki, Yoshinari TomaruArticle type: Article
1952 Volume 8 Issue 3 Pages 153-157
Published: November 30, 1952
Released on J-STAGE: June 02, 2017
JOURNAL FREE ACCESSWe measured the room noise spectra at subscribers'telephone location in Tokyo with sound level meter and filters, and couldn't detect the difference for the kinds of profession (residences, offices, shops, and factories)in singnificant level 5%. We estimated the noise spectra of various profession, of which results approximately agreed with Hoth's data. We also measured the room noise levels, and its mean value was found to be 57. 4 phon.View full abstractDownload PDF (425K)
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