Patent ID: 7926323

Claim:
A thermal conductivity measuring method using a microheater which is supported in air and provided in an ambient gas, the method comprising: calculating a heat radiation coefficient C=Ph/(Th−To) from the microheater in accordance with a power Ph applied to the microheater, a heater temperature Th, and an ambient temperature To at that moment; and obtaining a thermal conductivity λ (T) of the ambient gas from the calculated heat radiation coefficient C based on a proportional relation C=K·λ (T) between the thermal conductivity λ (T) of the ambient gas and the heat radiation coefficient C at a measurement temperature T, wherein K=(2/d)·(S), where d is a thickness of a temperature boundary layer of the ambient gas, and S is a heat radiating area of the microheater; wherein the thermal conductivity λ (T) is obtained based on the calculated heat radiation coefficient C by referring to a table in which the proportional relation between the thermal conductivity λ (T) of the ambient gas and the heat radiation coefficient C at the measurement temperature T is registered.