We attempt to compute the Surface Average Heat Flow （SAHF） from long-term temperature observations of one hundred seventy-seven observational points at the depths of 0.8, 1.6, and 3.2 m, which were relatively evenly...We attempt to compute the Surface Average Heat Flow （SAHF） from long-term temperature observations of one hundred seventy-seven observational points at the depths of 0.8, 1.6, and 3.2 m, which were relatively evenly distributed in China's Mainland. We first employ Fourier transformation to remove the influence of atmospheric temperature variations from the observation series, which are classified into the type of the steady-state temperature monotonously increasing with depth （type I） and other three types. Then we compare our results obtained from the data of type I, of which the values are thought to equal to those of the mean borehole heat flow, with those obtained from traditional heat flow observations mainly distributed in North China Craton. In computations of the SAHF at the observation stations, we deduce the thermal diffusivity and volumetric specific heat of the soil by employing harmonic solutions of the heat conduction equation for the same moisture group as the first step, and then we determine the SAHF using Fourier＇s law. Our results indicate that the SAHF derived from shallow earth geothermal data can reflect the heat flow field to a large extent.展开更多
The Franz-Wiedemann law is similar to Ohm＇s law in that it applies to an important but narrow set of materials.ln 1853 R. Franz and G. Wiedemann observed that in metals the ratio of the thermal conductivity to the el...The Franz-Wiedemann law is similar to Ohm＇s law in that it applies to an important but narrow set of materials.ln 1853 R. Franz and G. Wiedemann observed that in metals the ratio of the thermal conductivity to the electrical conductivity is a constant.This observation suggests that whatever mechanism or particle is involved in the transmission of electrical current through a metal may also be responsible for the transmission of heat.ln this paper we present an inexpensive and quick experiment through which this law may be verified for copper, aluminum and zinc.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.4087404741174084)
文摘We attempt to compute the Surface Average Heat Flow （SAHF） from long-term temperature observations of one hundred seventy-seven observational points at the depths of 0.8, 1.6, and 3.2 m, which were relatively evenly distributed in China's Mainland. We first employ Fourier transformation to remove the influence of atmospheric temperature variations from the observation series, which are classified into the type of the steady-state temperature monotonously increasing with depth （type I） and other three types. Then we compare our results obtained from the data of type I, of which the values are thought to equal to those of the mean borehole heat flow, with those obtained from traditional heat flow observations mainly distributed in North China Craton. In computations of the SAHF at the observation stations, we deduce the thermal diffusivity and volumetric specific heat of the soil by employing harmonic solutions of the heat conduction equation for the same moisture group as the first step, and then we determine the SAHF using Fourier＇s law. Our results indicate that the SAHF derived from shallow earth geothermal data can reflect the heat flow field to a large extent.
文摘The Franz-Wiedemann law is similar to Ohm＇s law in that it applies to an important but narrow set of materials.ln 1853 R. Franz and G. Wiedemann observed that in metals the ratio of the thermal conductivity to the electrical conductivity is a constant.This observation suggests that whatever mechanism or particle is involved in the transmission of electrical current through a metal may also be responsible for the transmission of heat.ln this paper we present an inexpensive and quick experiment through which this law may be verified for copper, aluminum and zinc.
