The enhancement of near-field radiative heat transfer(NFRHT)has now become one of the research hotspots in the fieldsof thermal management and imaging due to its ability to improve the performance of near-field thermo...The enhancement of near-field radiative heat transfer(NFRHT)has now become one of the research hotspots in the fieldsof thermal management and imaging due to its ability to improve the performance of near-field thermoelectric devices and near-field imaging systems.In this paper,we design three structures(multilayer structure,nanoporous structure,and nanorod structure)based on high-entropy alloys to realize the enhancement of NFRHT.By combining stochastic electrodynamicsand Maxwell-Garnett's description of the effective medium,we calculate the radiative heat transfer under different parametersand find that the nanoporousstructure has the largest enhancement effect on NFRHT.The near-field heat transfer factor(q)of this structure(q=1.40×10^(9)W/(m^(2)·K))is three times higher than that of the planestructure(q=4.6×10^(8)W/(m^(2)·K)),and about two orders of magnitude higher than that of the SiO2plate.Thisresult providesa freshidea for the enhancement of NFRHT and will promote the application of high-entropy alloy materials in near-field heat radiation.展开更多
It is difficult to obtain nanoscale grain size and strong texture in hot-deformed magnets simultaneously,which is responsible for the low magnetic properties of nanocrystalline magnets.In this study,a strong texture w...It is difficult to obtain nanoscale grain size and strong texture in hot-deformed magnets simultaneously,which is responsible for the low magnetic properties of nanocrystalline magnets.In this study,a strong texture was realized in a nanocrystalline Nd-Fe-B magnet via a high-stress low-temperature rapid deformation.Strong texture formation is ascribed to the high stress,which promotes the preferential growth of grains by increasing strain energy anisotropy.The nanocrystalline formation is ascribed to the low deformation temperature(below the melting point of the Nd-rich phase)and short deformation time.The effects of deformation temperature and applied stresses on the microstructure and magnetic properties were investigated in detail.Thus,the highest maximum energy product of 43.3 MGOe is obtained.展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.52101233,51931007,and 52071279)the Hebei Natural Science Foundation(No.E2022203010)the Innovation Capability Improvement Project of Hebei Province(No.22567605H).
文摘The enhancement of near-field radiative heat transfer(NFRHT)has now become one of the research hotspots in the fieldsof thermal management and imaging due to its ability to improve the performance of near-field thermoelectric devices and near-field imaging systems.In this paper,we design three structures(multilayer structure,nanoporous structure,and nanorod structure)based on high-entropy alloys to realize the enhancement of NFRHT.By combining stochastic electrodynamicsand Maxwell-Garnett's description of the effective medium,we calculate the radiative heat transfer under different parametersand find that the nanoporousstructure has the largest enhancement effect on NFRHT.The near-field heat transfer factor(q)of this structure(q=1.40×10^(9)W/(m^(2)·K))is three times higher than that of the planestructure(q=4.6×10^(8)W/(m^(2)·K)),and about two orders of magnitude higher than that of the SiO2plate.Thisresult providesa freshidea for the enhancement of NFRHT and will promote the application of high-entropy alloy materials in near-field heat radiation.
基金supported by the National Natural Science Foundation of China(51931007,51971196,52071279,52101234)。
文摘It is difficult to obtain nanoscale grain size and strong texture in hot-deformed magnets simultaneously,which is responsible for the low magnetic properties of nanocrystalline magnets.In this study,a strong texture was realized in a nanocrystalline Nd-Fe-B magnet via a high-stress low-temperature rapid deformation.Strong texture formation is ascribed to the high stress,which promotes the preferential growth of grains by increasing strain energy anisotropy.The nanocrystalline formation is ascribed to the low deformation temperature(below the melting point of the Nd-rich phase)and short deformation time.The effects of deformation temperature and applied stresses on the microstructure and magnetic properties were investigated in detail.Thus,the highest maximum energy product of 43.3 MGOe is obtained.
