We present an advanced approach for the thermodynamic modeling of metal hydrides within the Calculation of Phase Diagrams (CALPHAD) framework. As the traditional CALPHAD method requires significant and time-consuming ...
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A comprehensive understanding of phonon transport is essential to develop effective solutions for heat dissipation. Gallium nitride (GaN), a representative of third-generation power semiconductors, has been extensivel...
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A comprehensive understanding of phonon transport is essential to develop effective solutions for heat dissipation. Gallium nitride (GaN), a representative of third-generation power semiconductors, has been extensively studied regarding its thermodynamics and lattice dynamics. However, the temperature-dependent phonon properties, especially the anharmonicity at high temperatures, are poorly understood. Here, by combining inelastic neutron scattering (INS) experiments and calculations including the temperature effect based on machine learning potentials, we report the high-order phonon anharmonicity in GaN over a wide temperature range. Our calculations agree well with the experimental phonon dispersion, density of states and entropy, underlining the significance of anharmonicity of GaN at elevated temperatures. Moreover, considering the four-phonon processes, the calculated thermal conductivity is suppressed by 20%, and the anisotropy is also reduced gradually with increasing temperature. Such behavior arises mainly from the large four-phonon scattering channels between 20 and 30 meV, where the critical scattering rule for the three-phonon process is largely restricted at high temperatures. Our study highlights the importance of high-order phonon anharmonicity for thermal transport in GaN and provides a theoretical reference for thermal management in other related semiconductors.
The recent development of perovskite-based lasers showcased the outstanding optical properties of the material such as high absorption coefficient and high quantum yield. The lasers were demonstrated in the form of na...
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To investigate the effect of separate Al_(2)Ca and Mg_(2)Ca phases on the corrosion properties of Mg−Al−Ca−Mn alloys,OM,SEM,immersion and electrochemical tests were conducted on the as-cast and ECAP Al_(2)Ca-containin...
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To investigate the effect of separate Al_(2)Ca and Mg_(2)Ca phases on the corrosion properties of Mg−Al−Ca−Mn alloys,OM,SEM,immersion and electrochemical tests were conducted on the as-cast and ECAP Al_(2)Ca-containing(2Ca)and Mg_(2)Ca-containing(4Ca)*** the beginning of corrosion,the two as-cast alloys are corroded slowly compared with ECAP *** prolonging the corrosion time,the corrosion of ECAP alloys becomes slighter than that of as-cast alloys,which is mainly ascribed to the dispersion and refinement of the second phase in ECAP ***,the corrosion degree of 2Ca alloys is always slighter than that of 4Ca alloys,suggesting that Al_(2)Ca phase is more beneficial to the enhancement of corrosion resistance of Mg−Al−Ca−Mn based alloys than Mg_(2)Ca ***,based on the examinations of corrosion surface and electrochemical testing results,different corrosion mechanisms caused by the distributions and morphology of Al_(2)Ca and Mg_(2)Ca phases are discussed.
To address the electromagnetic wave pollution issue induced by widespread applications of electronic devices and 5 G technology, multifunctional epoxy composites reinforced with both 0-D magnetite (Fe 3 O 4 )@polyanil...
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To address the electromagnetic wave pollution issue induced by widespread applications of electronic devices and 5 G technology, multifunctional epoxy composites reinforced with both 0-D magnetite (Fe 3 O 4 )@polyaniline with a core–shell structure and 1-D carbon nanofibers were prepared by the in situ polymerization method. The nanocomposites exhibit good mechanical properties, thermal stability, and electromagnetic wave absorption performance. The reflection loss can be −55.73 dB at 7.17 GHz, and the effective absorption bandwidth can reach 1.96 GHz at 3.2 mm. The excellent electromagnetic wave absorption performance is related to the magnetic loss (eddy current loss, magnetic resonance) and dielectric loss (interfacial polarization loss, dipolar polarization loss, and conduction loss). Moreover, when the mass ratio of 0-D Fe 3 O 4 @polyaniline to 1-D carbon nanofiber is 48:1, the tensile strength is improved to 47.8 MPa compared with epoxy composites with only Fe 3 O 4 @polyaniline particles. Meanwhile, the thermal stability and thermal conductivity of the multifunctional epoxy composites were systematically analyzed as well. This work provides a new idea to prepare the multifunctional epoxy composites with excellent electromagnetic wave absorption performance.
The promotion of electric vehicles brings notable environmental and economic advantages. Precisely estimating the state of health (SOH) of lithium-ion batteries is crucial for maintaining their efficiency and safety. ...
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The protection of rusted carbon steel in acid corrosion environments is of great significance for equipment to keep safe *** this work,we presented a method to protect the rusted steel by ru st conversion treatment an...
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The protection of rusted carbon steel in acid corrosion environments is of great significance for equipment to keep safe *** this work,we presented a method to protect the rusted steel by ru st conversion treatment and epoxy *** acid was selected as rust conversion *** acid,D-limonene and nano-ZrO_(2)were used to improve the corrosion resistance of epoxy *** Raman spectra,Xray diffraction and 3 D confocal images were used to characterize the rust conversion *** hesion test showed that the loss of wet adhesion of the optimal coating was relatively low due to the addition of tannic acid,limonene and nano-ZrO(2).The corrosion resistance of five different coatings was investigated by scanning electron microscopy(SEM)and electrochemical *** show that after 264 h acid immersion,the low frequency resistance of the optimal coating consisting of rust conversion treatment and additives is 10^(7)Ωcm^(2),three orders magnitude higher than that of the pristine ***,SEM indicates that the optimal coating possesses a smooth surface and an unbroken interface between substrate and ***,the corrosion-resistant mechanism of the hybrid coating is proposed.
Energy storage materials for electric vehicles and energy storage systems must be able to supply high capacity quickly, which requires efficient Li-ion transport within the anode active material. The transport of Li i...
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To fabricate sandwich-structure composite of porous metal with nonporous surface layer, the nonporous skin layer was formed on surface of open-cell type nickel foam from aluminum powder by friction stir powder increme...
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