Thermal conductivity measurements over variable lengths on nanostructures such as nanowires provide important information about the mean free paths (MFPs) of the phonons responsible for heat conduction. However, nearly all of these measurements have been interpreted using an average MFP even though phonons in many crystals possess a broad MFP spectrum. Here, we present a reconstruction method t...

The thermal conductivity of superconducting MgB 2 was studied in both the superconducting and normal state region. The latter is almost equally determined by the electronic-and the lattice thermal conductivity. In the superconducting state, however, the lattice thermal conductivity is larger. The electronic thermal conductivity below T c was derived from the experimental data considering the Ba...

We consider the heat equation with spatially variable thermal conductivity and homogeneous Dirichlet boundary conditions. Using Method of Fokas or Unified Transform Method, we derive solution representations as limit solutions constant-coefficient interface problems where number subdomains interfaces becomes unbounded. This produces an explicit representation solution, from which can compute de...

This study examines the influence of radial thickness on the thermal conductivity of thin metallic wires. While size effects on the electrical conductivity of thin wires have been discussed in the literature, research into size effects on thermal conductivity still requires investigation. At such small length scales, the assumption that the reduced electrical conductivity can be simply related ...

The aim of this work is to determine the thermal conductivity of mesoporous silicon (PoSi) by fitting the experimental results with simulated ones. The electrothermal response (resistance versus applied current) of differently designed test lines integrated onto PoSi/silicon substrates and the bulk were compared to the simulations. The PoSi thermal conductivity was the single parameter used to ...

Absorption of photons in a metal is varied up to the photon energy spectrum. For example, larger wavelength photons generally can be more easily absorbed when they pass through an absorber while shorter ones tend to penetrate. This spectral variation of photon energy absorption takes place angularly due to the angular variation of the synchrotron radiation power. In this note, the effects of ph...

Thermal conductivity κ(T ) and thermoelectric power S(T ) studies on (Y,Gd)Ba2(Cu1−xMnx)3O7−δ (x 0.02) superconductors are presented here. Thermal conductivity for all the samples exhibits a hump below the superconducting transition temperature Tc. The peak height of the hump decreases with the Mn content in both the Yand Gd-based systems, barring GdBa2(Cu0.99Mn0.01)3O7−δ. The peak height reduc...

The maximal value of thermal conductivity κmax of the perfect wurzite GaN crystal containing isotopes of natural abundance is estimated. Our upper limit of κ = 4800 W/Km at Tmax = 32 K is smaller than calculated by Liu and Balandin κ = 6000 W/Km and higher than obtained by Slack et al κ = 3750W/Km. The phenomenological dependence κ ∝ T obtained by Mion et al for the temperature interval 300− 45...