著者

清水 優史 龍前 三郎

出版者

一般社団法人 日本生体医工学会

雑誌

医用電子と生体工学 (ISSN:00213292)

巻号頁・発行日

vol.31, no.1, pp.53-60, 1993 (Released:2011-10-14)

参考文献数

18

被引用文献数

1

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To simulate blood pressure measurement done by medical doctors, a new type stethoscope, which is a commercialy available stethoscope equipped with an eddy-current displacement sensor and a microphone, is developed. Using this stethoscope and impedance plethysmograph, pulse wave-forms and sounds distal to the cuff and volume change of the artery under the cuff were measured in various experiments. In some experiments, common blood pressure measuring process is adopted and, in other experiments, cuff-pressure is kept constant. From the experimental results, the following facts are known. 1) Blood flow rate coming from upstream in the collapsed artery under the cuff is not affected by arterial pressure distal to the cuff. 2) Always the same sounds are produced when experimental conditions are kept constant. 3) When sounds are heard there exist always steep wave fronts. From these facts, the true mechanism of Korotkoff sound generation is known to be hydrolic-jump formation at the wave front during pressure wave propagation through collapsed artery segment under the cuff.

著者

清水 優史 谷田 好通

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.48, no.434, pp.1936-1944, 1982-10-25 (Released:2008-03-28)

参考文献数

9

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血圧測定のよりどころであるコロトコフ音の発生機構のうち最低血圧でのそれを, 実験及び理論計算により明らかにした. コロトコフ音は外圧によりいくぶん圧平された管部を圧力波が出播する際, 波の先頭部に形成される圧力不連続面(衝撃波面)が管を急激に膨張させることにより生ずる. この衝撃波面は管法則の非線形性に起因する波の追いつき現象により作られ, その強さは管の圧平の度合と圧平部長さにより決定される.

著者

清水 優史

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.50, no.460, pp.3107-3115, 1984-12-25 (Released:2008-03-28)

参考文献数

9

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The genesis of Korotkoff sound at high cuff pressure has been made clear by the model expreimental study using the thin walled silicon rubber tube being modified to have zero internal cross sectional area as an artery ehen compressed by the relatively higher external pressure than the internal one. The sound is generated by the steep pressure wave front formed in the course of pressure wave propagation through the completely collapsed tube segment under the cuff. The amplitude of the pressure wave penetrating into the collapsed tube segment and that of the steep wave front reaching to the distal end of the segment, measured from the artery also weakens correspondingly and, at some Peb, the sound becomes unaudible. The pressure wave form depends strongly on the transmural pressure at the distal end of the collapsed segment.

著者

清水 優史

出版者

バイオメカニズム学会

雑誌

バイオメカニズム学会誌 (ISSN:02850885)

巻号頁・発行日

vol.36, no.3, pp.132-137, 2012 (Released:2016-04-15)

参考文献数

4

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長い首が呼吸の妨げになっていると言われるキリンの呼吸に関するパラメータを測定する目的で,腹部表面の呼吸に伴う変位をステレオカメラシステムを使用して測定することが試みられた.その中で縞模様が有効なターゲットになることが知られた.ステレオカメラシステムによるターゲットの変異計測から,呼吸量を推定する方法の精度が,人の実験によって調べられた.その結果,カメラを腹部の半分を見られる適当な位置に設置すれば,ある程度の精度で測定が可能と考えられる結果が得られた.

著者

清水 優史

出版者

一般社団法人 日本機械学会

雑誌

IIP情報・知能・精密機器部門講演会講演論文集 2002 (ISSN:24243140)

巻号頁・発行日

pp.165-166, 2002-03-22 (Released:2017-06-19)

著者

嶋脇 聡 龍前 三郎 清水 優史

出版者

社団法人 日本流体力学会

雑誌

日本流体力学会誌「ながれ」 (ISSN:02863154)

巻号頁・発行日

vol.19, no.4, pp.280-281, 2000-08-30 (Released:2011-03-07)

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The flow downstream to a contraction in a tube with bleeding flow was investigated by numerical analysis. The bleeding flow was orthogonally induced with tube axis from circumferential entrance. In the analysis, axisymmetrical and laminar flow was assumed.The calculated results were analyzed with respect to the following three parameters.· ratio Qb/Q of bleeding flow rate Qb to that of flow from contraction Q. · relative position of reattachment point of stream from the contraction and bleeding point.· ratio d/D of diameter of the contraction d to that of down stream tube D. From the results, it was clarified that all these parameters had the influence on the flow downstream to the contraction and pressure loss caused by bleeding flow. The pressure loss by bleeding flow could be lowered by decreasing of Qb/Q, setting the bleeding point far downstream to the contraction, and by increasing of d/D. Moreover, by normalizing the dimension of settings by Reynolds number in the contraction, the similarities of flow and of pressure distribution alone the tube wall were shown.