日本音響学会誌

超音波キャビテーション腐食に対する直流電流の効果

高橋純夫, 熊本乙彦

原稿種別: 本文
1973 年 29 巻 12 号 p. 713-718
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_713

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Many experiments have been performed by various investigators concerning the erosion of metals caused by the ultrasonic cavitation, there being many factors which affect this phenomenon. The authors conducted the following experiment in this paper. The cylindrical testpiece of aluminum, 18 mm in diameter and 20 mm in length, is set in front of the radiating surface of a stainless-steel solid-horn driven by a bolt-clamped Langevin-type piezoelectric (PZT) transducer. The dc voltage or the dc pulse voltage is applied between the testpiece and the radiating surface of the horn, with the testpiece as cathode or anode. The weight loss of the testpiece by erosion under irradiation of ultrasound and application of voltage, is measured. The erosion first increases slightly then decreases rather sharply with the increase of the dc current in case the testpiece is cathode (Fig. 3). The behavior is more complex when the testpiece is anode : the erosion first increases slightly, then decreases and finally increases almost linearly as the dc current increases (Fig. 7). Also an experiment with dc pulse current has been performed with the testpiece as cathode, but no difference is observable between the dc current and the dc pulse current, provided that the total amount of current is the same (Fig. 3 and Fig. 6). When the dc voltage is applied, with the testpiece as anode and without ultrasonic irradiation, a linear increase in erosion is observed with the increase of the dc current (Fig 7). It is concluded that the large difference in erosion of the aluminum testpiece acording as the testpiece is cathode or anode, is mainly due to the effect of the electrolytic erosion, while the mechanical effect of the cavitation is equally reduced in both cases the testpiece is cathode and anode. Although the mechanism is not ascertained as yet, the reduction of the mechanical effect of cavitation is presumably due to the electrolytic production of large gas bubbles preventing cavitation.

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時間的に変化する周波数スペクトルのオンラインカラー表示

越川常治, 中野康明, 小林正治, 中山剛, 潮田真

原稿種別: 本文
1973 年 29 巻 12 号 p. 719-726
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_719

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The construction, function, displaying method, and example of display of a three-dimensional on-line displaying system for sound spectrogram are shown. In this system, frequency analysis (FFT) is done by a computer, and its results (frequency spectrogram) are displayed on a color picture tube changing the magnitude of frequency component to colors. Following two systems are presented : 1) A system using a large-type computer HITAC-5020 in which the data-input and analysis are carried out by means of "off-line", and the data-output and display of the analyzed results are carried out by means of "on-line". 2) A system using a small-type-computer HITAC-10 in which all steps from input to display are carried out by means of "on-line". It is shown that former system 1) is suitable for displaying the abundant data and latter 2) is suitable for handling the input data required to obtain quick response. Two methods of display are shown. One is the moving-pattern method in which the spectrograms are displayed continuously an electric news-sign-board. The other is a method Combined with the above-mentioned one and the standing-pattern displaying method in which the analyzed results to be given intermittently and slowly are able to display continuously and slowly in the same timing as the analyzed results. The arrangement of color is decided so that each color assigned to each step of intensity is sensed continuously and at equal intervals on the sensory response. In this system, 15 steps of color are used, and red color is selected in order to correspond to the highest step of intensity and blue color to the lowest one. A fragment of the effect of these systems is shown with an example of analysis and display for the sailing sound of tanker.

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パルス計数法による筋電図からの神経指令の抽出

今泉敏, 比企静雄

原稿種別: 本文
1973 年 29 巻 12 号 p. 727-729
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_727

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海洋における超音波利用の沿革

橋本富寿

原稿種別: 本文
1973 年 29 巻 12 号 p. 730-733
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_730

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ソニックブームの影響

五十嵐寿一

原稿種別: 本文
1973 年 29 巻 12 号 p. 734-737
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_734

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新NHKホールパイプオルガンの音響設計

望月広幸

原稿種別: 本文
1973 年 29 巻 12 号 p. 738-742
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_738

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空調機騒音データのミニコンピュータによるオンライン処理システム

立花重春, 後藤康之

原稿種別: 本文
1973 年 29 巻 12 号 p. 743-747
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_743

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東京都の建設工事振動調査

永田穂

原稿種別: 本文
1973 年 29 巻 12 号 p. 748-754
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_748

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全ソ連邦音響学大会に出席して

菊池喜充

原稿種別: 本文
1973 年 29 巻 12 号 p. 755-758
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_755

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IEC SC60A(録音)のミュンヘン会議に出席して

松岡進

原稿種別: 本文
1973 年 29 巻 12 号 p. 759-762
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_759

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IEC/SC29D/WG4のRotterdam会議

井出正男

原稿種別: 本文
1973 年 29 巻 12 号 p. 763-764
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_763

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ワウ・フラッター

境久雄

原稿種別: 本文
1973 年 29 巻 12 号 p. 765-769
発行日: 1973/12/01
公開日: 2017/06/02

DOIhttps://doi.org/10.20697/jasj.29.12_765

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