Abstract
The mechanism of smell detection in animals has not fully been explained. Yet, we can create engineering equivalents. And then, we can open a new field of application such as for keeping environmental security from hazardous or toxic gases, for searching mineral resources by detecting very rare components in the air, and for identifying individuals by their smells. One of the most promising sensors of smell is semiconductor gas sensor. Animal's sense of smell shows high resolution and wide dynamic range. The key of having such features is to catch the changes of smell components. And if we recall the fact that animals do respiration through their noses, we may get an idea that the information about the smell might be encoded in the transient responses of the olfactory cells. Then the authors are focusing their attention on extracting time axis information using a single gas sensor. As the first step they investigated the possibility of gas identification from the transient sensor responses caused by ON-OFF operation of gas components. As the results, gas identification can be performed by extracting two parameters from the responses. One of them approximately corresponds to the diffusion coefficient, and the other represents the effectiveness of the gas to the sensor. Different gas species will be plotted on different place in the two dimensional space which have the two parameters as the axes. Once the gas species has been identified, the concentration of it also can be determined from the concentration-resistance curve for each gas species.
