GAS PHYSICAL PROPERTY VALUE MEASURING SYSTEM, GAS PHYSICAL PROPERTY VALUE MEASURING METHOD, HEAT VALUE CALCULATING FORMULA FORMING SYSTEM, HEAT VALUE CALCULATING FORMULA FORMING METHOD, HEAT VALUE CALCULATING SYSTEM AND HEAT VALUE CALCULATING METHOD

PROBLEM TO BE SOLVED: To provide a device capable of stably measuring the physical property value of gas. SOLUTION: The gas physical property value measuring system includes: a microchip 8A containing a heating resistor; a drive circuit 303 applying a plurality of different powers to the heating resistor of the microchip 8A and generating heat from the heating resistor of the microchip 8A at a plurality of different heating temperatures; a radiation coefficient calculating module 301 calculating the radiation coefficient of the gas on the basis of a plurality of respective power values, a plurality of respective heating temperature values and the gas temperature value of the gas thermally equilibrated with the heating resistor; a sonic velocity sensor 262 detecting the sonic velocity of the gas; and a density calculating module 311 for calculating the density of the gas on the basis of the detected sonic velocity. The drive circuit 303 stops the feed of power to the heating resistor at least once during the generation of heat at a plurality of different heating temperatures from the heating resistor. COPYRIGHT: (C)2011,JPO&INPIT