THE JOURNAL OF THE ACOUSTICAL SOCIETY OF JAPAN

[title in Japanese]

[in Japanese]

Article type: Article
1957 Volume 13 Issue 2 Pages i-
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_i

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On the Ultrasonic Field near the Circular Piston-like Source (1) : Visualization of the Ultrasonic Field

Yasuo Torikai, Katsuo Negishi

Article type: Article
1957 Volume 13 Issue 2 Pages 117-123
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_117

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A simple method for the visualization of ultrasonic fields is described, which requires no special material except conventional photographic paper and developer. A transducer was set in a tank filled with a dilute solution of photographic developer. A sheet of photographic paper previously exposed to light uniformly was supported in the liquid and irradiated ultrasonically. After 1 minute or so, the darkened diffracion pattern appeared gradually on the paper. Then, the paper was fixed in the usual manner. The pattern obtained by using the circular piston-like source consists of concentric circles, the radii and the number of these circles varying regularly with the distrance between the paper and the transducer. The appearance of these diffraction patterns can be explained by applying the method of the Fresnel's zones, known in physical optics, to sound diffraction problems. A detailed theoretical calculation of the sound field near the source will be described in the next paper.

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On Observed Abnormal Decay Patterns for Ultrasonic Waves in Metal Rods

Jobu Awatani, Hiroshi Miyamoto

Article type: Article
1957 Volume 13 Issue 2 Pages 123-128
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_123

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Abnormal decay patterns in attenuation are investigated for longitudinal ultrasonic waves in cylindrical rods. These abnormal patterns seem to be caused by two effects. (1) One is the interference between several modes excited in the rod by a quartz crystal transducer: McSkimin's analysis can well explain the observed results. (2) The other effect is caused by residual stresses or the fiber structure which are believed to be produced in the process of forming the material: the appropriate annealing is effective for eliminating this effect for some material. A formula is derived to discriminate whether the abnormal decay is due to the interference between the first mode and the second mode or not.

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Sound Velocity and Molecular Sound Velocity in Aqueous Sugar Solutions

Otohiko Nomoto, Tadashi Kishimoto

Article type: Article
1957 Volume 13 Issue 2 Pages 129-137
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_129

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Ultrasonic velocity was measured on various sugar solutions (erythrite, fructose, mannite, rhamnose, sucrose, lactose and raffinose) by the method of ultrasonic interferometry at 1. 43Mc/sec and at temperatures between 5℃ and 30℃. Rao's molecular sound velocity was calculated for these solutions and was observed that the molecular sound velocity was a linear function of the concentration (=molar fraction of the solute) within the range of the concentrations investigated (up to about 20% in weight). The molecular sound velocities corresponding to the supercooled liquid states of the solute, as obtained by extrapolation from these straight lines, proved to be smaller than the values calculated from the additivity rules of the molecular sound velocity by employing Rao's atomic increments by about 10 to 20%. This may presumably be due to the effect of the branching of the sugar molecules.

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The Ultrasonic Doppler Method for the Cardiac Functional Test

Shigeo Stomura

Article type: Article
1957 Volume 13 Issue 2 Pages 138-143
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_138

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When an ultrasonic beam is radiated into the body by a transducer placed on the suface of the chest wall, the motion of the heart causes the so-called Doppler effect on the wave reflected from it. Thus, several kinds of beat tones whose frequencies are proportional to the speed of the heart motion are perceived at the earphones of the receiving apparatus. Designating the frequency of these beat as fd(c/s), the speed of the reflecting area as u_0(cm/sec), the ultrasonic wavelength in the body as λ(cm), the following relation holds between them. u_0=λ/2fd. Since λ is determined by the frequency of the ultrasound which is being used, the knowledge of fd makes it possible to investigate the behaviour of the reflecting region of the heart in motion. In the same way, the minute vibration of the heart surface or of the valvular structures which would be developed by the blood flow would cause the vibrational alterations in the phase of the reflected wave. Hence they can be detected as the vibrational tones of the same kind (in this case, chiefly, heart noises). The principal parts of the apparatus consist of a HF-oscillator, an ultrasonic transducer for the purpose of both transmission and reception, a detector-amplifier, an earphone and a recorder. The transducer is of barium-titanate, 1 cm in diameter. The positive electrode is separated into two concentric parts, the inner disc of 3 mm in diameter being used for transmission and the outer circular ring for reception. The sensitive range proves to be a beam of approximately 1 cm in diameter. Therefore, the investigations of the heart is performed on the distinct parts of this small extension. By supplying a frequency-selecter of bandpass type for the amplifier, it becomes possible to separate and select the movements of the particular parts of the heart. The HF-oscillator is realized by a 6V6 type tube, operating as a self-oscillator. The ultrasonic power output is calculated to be 20 mW/cm^2. In practice, the ultrasonic transducer, attached to the end of a flexible cable, is placed at the various positions on the chest wall, and the Doppler beat due to the movements of the corresponding parts are made audible or recorded. There are three kinds in these tones: 1. Higher Doppler beat. (Movements of the valves) 2. Lower Doppler beat. (Movements of the surface of the heart) 3. Doppler heart noises. (Heart noises)

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Theory of Mechanical Filter with Resonator Disk

Masashi Konno

Article type: Article
1957 Volume 13 Issue 2 Pages 143-148
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_143

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This is a theoretical treatment of a mechanical filter consisting of disc resonators vibrating in bending mode coupled by longitudinally vibrating bars. The equivalent mechanical circuit for a certain mode(i. e. , the 1st mode) of vibration of the resonator is obtained. General equivalent electrical network for the mechanical filter including the electromechanical transducers is presented. Terminal matching, specific band, and other characteristic features, which are important for the design of mechanical filters are discussed.

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[title in Japanese]

[in Japanese], [in Japanese]

Article type: Article
1957 Volume 13 Issue 2 Pages 149-153
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_149

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Error of Reverberation Time due to the Writing Speed of the Recorder

Juichi Igarashi

Article type: Article
1957 Volume 13 Issue 2 Pages 154-155
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_154

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[title in Japanese]

[in Japanese]

Article type: Article
1957 Volume 13 Issue 2 Pages 156-174
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_156

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[title in Japanese]

[in Japanese]

Article type: Article
1957 Volume 13 Issue 2 Pages 175-182
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_175

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[title in Japanese]

[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...

Article type: Article
1957 Volume 13 Issue 2 Pages 183-205
Published: June 30, 1957
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.13.2_183

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