著者

浅見 義弘 黒部 貞一 西辻 昭

出版者

北海道大学

雑誌

北海道大學工學部研究報告 (ISSN:0385602X)

巻号頁・発行日

vol.18, pp.1-13, 1958-05-30

著者

吉田 豊 門脇 良一 畑中 雅彦 坂口 威 西辻 昭

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.111, no.4, pp.219-224, 1995-04-25 (Released:2011-01-27)

参考文献数

23

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In the past, many methods of measuring gas concentration were developed. However, limitations lixe; selectivity in the kind of gases the system can measure, range of gas quantity and pre-treatment requirements prevented the wider applications of these techniques.The objective of this research is to develop a method for measuring gas concentrations that is free from the above mentioned limitations. In this regard, the principle and the technique of measuring the sound generated by the spectral diffraction of a laser beam was investigated.This technique is fundamentally different from any other usual spectroscopic analysis: this is an indirect method which measures the acoustic pressure emitted from gas when the photo energy is supplied to it.First, miniaturized laser equipment was fabricated based on diagrams and gas flow type. Then the primary parameters in this system in terms of the sensitivity of this system are the following; the laser's power output, the chopping frequency and the acoustic cell shape. The influence of these factors on the sound generated by the beam were investigated.As an condition of this system, a CO2 laser with output power of under 5.0W, a radial cell and a chopping frequency of 20Hz were chosen. As a result of the experiments under this condition, we confirmed that acoustic signal is proportional to gas concentration of single and mixture gas.For high sensitivity analysis of measuring acoustic signal, the noise characterics in measuring system, which was occured by discharge tube of laser, microphone, acoustic cell and so on, were measured and were eliminated. The new discharge tube of laser without noise was fabricated. And we maked out for the about thirty kinds of diameter, axies lenngth and mass of acoustic cell. The chopping frequency was chosen outside for frequency of noise. It was found that the gas concentrations of Ethylene was measurable in the ranges of concentration 1ppm-10%.

著者

木村 慎也 竹谷 弘 畑中 雅彦 坂口 威 西辻 昭 和田 誠

出版者

一般社団法人電子情報通信学会

雑誌

電子情報通信学会技術研究報告. CS, 通信方式

巻号頁・発行日

vol.95, no.97, pp.9-16, 1995-06-20

被引用文献数

3

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南極では、1988年から一年間気象レーダによる雲と降水の観測が行われた。この時、ラジオ・ゾンデによる上空の気温の測定とビデオカメラ装置による地上での降雪粒子の観測も行われた。本論文では、観測されたこれらのデータと、観測されていない南極上空の粒径分布の代わりとして、粒径分布の高度変化を推定し、レーダ方程式から昭和基地上空における降雪強度変化を求めて推定した。