Gas-sensing system based on the cyclic temperature

A Review of Gas Measurement Set-Ups

Measurements of the properties of gas-sensitive materials are a subject of constant research, including continuous developments and improvements of measurement methods and, consequently, measurement set-ups. Preparation of the test set-up is a key aspect of research, and it has a significant impact on the tested sensor. This paper aims to review the current state of the art in the field of gas-sensing measurement and provide overall conclusions of how the different set-ups impact the obtained results.

Electronic Nose Based on Temperature Modulation of MOS Sensors for Recognition of Excessive Methanol in Liquors

An electronic nose based on metal oxide semiconductor (MOS) sensors has been used to identify liquors with excessive methanol. The technique for a square wave temperature modulated MOS sensor was applied to generate the response patterns and a back-propagation neural network was used for pattern recognition. The parameters of temperature modulation were optimized according to the difference in response features of target gases (methanol and ethanol). Liquors with excessive methanol were qualitatively and quantitatively identified by the neural network. The results showed that our electronic nose system could well identify the liquors with excessive methanol with more than 92% accuracy. This electronic nose based on temperature modulation is a promising portable adjunct to other available techniques for quality assurance of liquors and other alcoholic beverages.

Distinction of gases with a semiconductor sensor depending on the scanning profile of a cyclic temperature

A gas-sensing system based on a dynamic nonlinear response is reported to improve the selectivity in the sensor response toward sample gases. A cyclic temperature composed of fundamental and second harmonics was applied to a SnO(2) semiconductor gas sensor and the resulting conductance of the sensor was analyzed by fast Fourier transformation (FFT). The dynamic nonlinear responses to the gas species were further characterized depending on the scanning profile of the temperature. These characteristic sensor responses under the application of second-harmonic perturbation were theoretically considered based on a reaction-diffusion model for the semiconductor surface.