| 摘要 |
PROBLEM TO BE SOLVED: To measure trace constituent gas included in mixed gas with high precision. SOLUTION: By applying a voltage having a chaotic property on a heater coil 12B, fluctuation of a surface temperature of an n-type semiconductor 12A occurs, and an adsorption/desorption reaction peculiar to the kind and the concentration of gas corresponding to the fluctuation occurs, therefore, an output voltage VRI from a semiconductor gas sensor 12 is equipped with a chaotic property, Existence of chaos is confirmed by a spectral analysis, an auto- correlation analysis and a Liapunov index analysis, and a characteristic quantity of an chaos attractor in mixed gas is extracted, and a gas kind and a gas concentration value are operated by a neutral network. The chaos attractor has a different shape and magnitude corresponding to the gas kind and its concentration value of component gas in the mixed gas, and the chaos has initial sensitivity reflecting sensitively to slight difference of initial conditions, therefore, extremely slight difference of a gas atmosphere is amplified, and the gas kind and the concentration value of the component gas in the mixed gas can be operated accurately.
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