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Mean free path
About: Mean free path is a research topic. Over the lifetime, 4412 publications have been published within this topic receiving 114418 citations.
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TL;DR: In this article, the local mean free path of phonons with boundary effects was introduced, and the local thermal conductivity distribution from boundary to film bulk region was obtained, and boundary scattering effect was examined by introducing a phonon Knudsen layer thickness.
Abstract: In the study, we introduced the local mean free path of phonons with boundary effects. The local thermal conductivity distribution from boundary to film bulk region was obtained, and the boundary scattering effect was examined by introducing a phonon Knudsen layer thickness. We calculated the ratio of effective thermal conductivity to the bulk one and the results are in agreement with available data.
38 citations
38 citations
TL;DR: In this paper, the effective thermal conductivity of porous Si by means of the phonon Boltzmann transport equation is computed, and it is shown that the roughness of the pore walls plays an important role.
Abstract: In this work we compute the effective thermal conductivity of porous Si by means of the phonon Boltzmann transport equation. Simulations of heat transport across aligned square pores reveal that the thermal conductivity can be decreased either by increasing the pore size or decreasing the pore spacing. Furthermore, by including the surface specularity parameter we show that the roughness of the pore walls plays an important role when the pore size is comparable with the phonon mean free path, because to the increase in the surface-to-volume ratio. Thanks to these results, in qualitatively agreement with those obtained with Molecular Dynamics simulations, we gained insights into the scaling of thermal properties of porous materials and interplay between disorder at different length scales. The model, being based on a flexible multiscale finite element context, can be easily integrated with electrical transport models, in order to optimize the figure of merit ZT of thermoelectric devices.
38 citations
TL;DR: In this article, the photon-shielding parameters of stainless steels were calculated both experimentally and theoretically, and the photon energies were obtained from seven different radioactive sources (22Na, 60Co, 241Am, 109Cd, 137Cs, 152Eu and 133Ba).
38 citations
TL;DR: In this article, the fundamental parameters associated with electronic transport, that is the scattering time, mean free path, effective mass and hence microscopic mobility for free electrons, have been estimated from the free-carrier absorption, Hall effect and dc conductivity in an optically transparent and highly conducting (degenerate) new class of amorphous oxides.
Abstract: The fundamental parameters associated with electronic transport, that is the scattering time, mean free path, effective mass and hence microscopic mobility for free electrons, have been estimated from the free-carrier absorption, Hall effect and dc conductivity in an optically transparent and highly conducting (degenerate) new class of amorphous oxides. No sign anomaly is observed in the Hall effect and the optical conductivity measured at room temperature obeys the classical Drude formula. The dc conductivity is proportional to temperature below room temperature, suggesting that the transport is in a weak-localization regime at these temperatures.
38 citations