| 摘要 |
A sensor having an active sensing material exposed to the substance to be detected and an active reference material that is shielded from the substance to be detected. Thermocouples having a set of junctions proximate to the active sensing material and another set of junctions to the active reference material for measuring the temperatures at the respective materials. The junctions are connected differentially in that a difference of the two temperatures is measured. A heater is proximate and common to the two materials. Heat pulses may be applied to the materials via the heater and the temperatures are measured. If ambient factors or substances affect the active sensing material, its thermal response will be different than that of the active reference material, and a differential pulse-like indication of temperature will be detected. This indication will have certain characteristics of amplitude, shape and time, which indicate an identification of the type and concentration of substance detected by the sensor.
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