In the present paper, thermal conductivity coefficient of high-temperature molecular and atomic gases with excited electronic states is studied using both the kinetic theory algorithm developed by authors earlier and the well known simple expression for the thermal conductivity coefficient proposed by Eucken and generalized by Hirschfelder. The influence of large collision diameters of excited states on the thermal conductivity is discussed. The limit of validity of the Eucken correction is evaluated on the basis of the kinetic theory calculations; an improved model suitable for air species under high-temperature conditions is proposed.
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http://dx.doi.org/10.1063/1.4874257 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, P. R. China.
Thermoelectric technology enables the direct and reversible conversion of heat into electrical energy without air pollution. Herein, the stability, electronic structure, and thermoelectric properties of methoxy-functionalized MC(OMe) (M = Sc, Ti, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, and W) were systematically investigated using first-principles calculations and semiclassical Boltzmann transport theory. All MXenes, except those with M = Cr, Mo, and W, can be synthesized by substituting Cl- and Br-functionalized MXenes with deprotonated methanol, with stability governed by the M-O bond strength.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, Shanghai 20092, China.
In contrast to normal diffusion processes, thermal conduction in one-dimensional systems is anomalous. The thermal conductivity is found to vary with the length as κ∼L^{α}(α>0), but there is a long-standing debate on the value α. Here, we present a canonical example of this behavior in polymer-grafted spherical nanoparticle (GNP) melts at fixed grafting density and nanoparticle radius.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
We propose a mechanism to obtain chiral phononlike excitations from the bond-dependent magnetoelastic couplings in the absence of out-of-plane magnetization and magnetic fields. By mapping the hybrid excitation to its phononic analog, we reveal the impact of the lattice symmetry on the origin of the chirality. In the example of a triangular lattice ferromagnet, we recognize that the system is equivalent to the class D of topological phonons, and show the tunable chirality and topology by an in-plane magnetic field.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
Two-Dimensional transition metal dichalcogenides have been the subject of extensive attention thanks to their unique properties and atomically thin structure. Because of its unprecedented room-temperature magnetic properties, iron-doped MoS (Fe:MoS) is considered the next-generation quantum and magnetic material. It is essential to understand Fe:MoS's thermal behavior since temperature and thermal load/activation are crucial for their magnetic properties and the current nano and quantum devices have been severely limited by thermal management.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, USA.
AgSbTe is a promising p-type thermoelectric material operating in the mid-temperature regime. To further enhance its thermoelectric performance, previous research has mainly focused on reducing lattice thermal conductivity by forming ordered nanoscale domains for instance. However, the relatively low power factor is the main limitation affecting the power density of AgSbTe-based thermoelectric devices.
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