Temperature dependence of the properties of thermoelectric materials measured under steady-state isothermal conditions

2013 ◽  
Author(s):  
Jay R. Maddux ◽  
Patrick J. Taylor
1972 ◽  
Vol 27 (1) ◽  
pp. 138-140 ◽  
Author(s):  
George A. Sullivan ◽  
Sune Larsson ◽  
Per T. Thernquist

Abstract Steady-state distributions of Au, Ag and Cu tracers in Pb wafers subjected to temperature gradients have been determined. The effective heats of transport were + 5.8 ± 1.1 for Ag, - 0.5 ± 0.3 for Au, and of the order of + 35 for Cu (all in kcal/mole, positive values denoting the impurity migrating to the cold side of the Pb wafer). No significant temperature dependence of the heats of transport could be detected. The results are difficult to reconcile with existing theories of the intrinsic and electronic contribution to the heat of transport.


A line source technique has been developed for non-steady-state measurements of the therm al conductivities of liquids over an extended range of temperature. The accuracy of the method, which is an absolute one, has been critically exam ined. T hermal conductivities of liquid benzene, toluene, diphenyl, o-,m - and^p-terphenyl, estimated to be accurate to + 0*25 % , have been obtained. These results are discussed in terms of the effect of structure on the transport properties of liquids and the relation between the coefficient of thermal expansion and the temperature dependence of thermal conductivity.


1997 ◽  
Vol 109 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Michael Pusch ◽  
Uwe Ludewig ◽  
Thomas J. Jentsch

The chloride channel from the Torpedo electric organ, ClC-0, is the best studied member of a large gene-family (Jentsch, T.J. 1996. Curr. Opin. Neurobiol. 6:303–310.). We investigate the temperature dependence of both the voltage- and chloride-dependent fast gate and of the slow gate of the “double-barreled” ClC-0 expressed in Xenopus oocytes. Kinetics of the fast gate exhibit only a moderate temperature dependence with a Q10 of 2.2. Steady-state popen of the fast gate is relatively independent of temperature. The slow gate, in contrast, is highly temperature sensitive. Deactivation kinetics at positive voltages are associated with a Q10 of ∼40. Steady-state open probability of the slow gate (popenslow(V)) can be described by a Boltzmann distribution with an apparent gating valence of ≈2 and a variable “offset” at positive voltages. We note a positive correlation of this offset (i.e., the fraction of channels that are not closed by the slow gate) with the amount of expression. This offset is also highly temperature sensitive, being drastically decreased at high temperatures. Paradoxically, the maximum degree of activation of the slow gate also decreases at higher temperatures. The strong temperature dependence of the slow gate was also observed at the single channel level in inside-out patches. The results imply that within a Markovian-type description at least two open and two closed states are needed to describe slow gating. The strong temperature dependence of the slow gate explains the phenotype of several ClC-0 point-mutants described recently by Ludewig et al. (Ludewig, U., T.J. Jentsch, and M. Pusch. 1996. J. Physiol. (Lond.). In press). The large Q10 of slow gating kinetics points to a complex rearrangement. This, together with the correlation of the fraction of noninactivating channels with the amount of expression and the fact that the slow gate closes both protochannels simultaneously suggests that the slow gate is coupled to subunit interaction of the multimeric ClC-0 channel.


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