VO2-based radiative thermal transistor with a semi-transparent base

International audienc

Effective interface thermal resistance and thermal conductivity of dielectric nanolayers

International audienceAnalytical expressions for the effective interface thermal resistance (ITR) and thermal conductivitykof dielectricnanolayers are derived and analyzed, based on the analytical solution of the phonon Boltzmann transportequation under the gray relaxation time approximation. This is achieved by using accurate expressions for thetemperature and one-dimensional heatflux propagating across nanolayers supporting a diffusive phonon scat-tering at their interfaces. It is shown that the effective ITR between two layers can be symmetric on their thermalproperties, such that its asymptotic value in the ballistic regime is higher than that in the diffusive one. In theballistic-diffusive regime, the effective ITR depends strongly on the ratio=λLl/, between the layer thicknessLand mean free pathlof phonons. Our predictions for the effective ITR in the ballistic regime are in goodagreement with those of the diffuse mismatch model, while they differ by about 16%in the diffusive regime. Onthe other hand,kincreases withλuntil reaching saturation for bulk layers and agrees rather well with previouspredictions reported in the literature. The obtained results could be useful for analytically describing the heattransport in dielectric nanothinfilms and superlattices, in which the gray approximation is vali

Evolution of the Thermal Conductivity of Sintered Silver Joints with their Porosity Predicted by the Finite Element Analysis of Real 3D Microstructures

International audienceSilver paste sintering is a very promising technology for chip bonding in future power electronics modules owing to its high melting temperature and the good electrical and thermal properties among other classic solder alloys. However, in its sintered form, these joints contain nanometric/submicrometric pores that affect their thermal performance. The present study gives insight into the relationship between the material thermal conductivity and the real three-dimensional porous structure using finite element modelling. It is shown that over a certain pore fraction threshold (∼ 13%), the pore morphology has a non-negligible influence on the thermal conductivity. Results are also compared to predictions obtained by analytical models available in the literature

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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