Authors produced rapidly solidified T15 high speed steel powders by high pressure(5~ 6MPa) N_a atomization and liquid N_2 cooling,observed and analyzed the morphology and structure of the powders;at the same time,prep...Authors produced rapidly solidified T15 high speed steel powders by high pressure(5~ 6MPa) N_a atomization and liquid N_2 cooling,observed and analyzed the morphology and structure of the powders;at the same time,prepared bulk microcrystalline T15 high speed steel materials by hot extruding or HIPing and hot rolling of the powders,observed and measured the microstructure and performance of the bulk materials.It was shown that rapid solidification may change the solidification characteristics and structure of T15 high speed steel powder and improve the qualities and properties of T15 high speed steel materials.展开更多
This paper used 3 types of graphite with different physical structures as the porous matrix to prepare composite phase change materials(PCMs),and investigated their photo-thermal conversion performance and application...This paper used 3 types of graphite with different physical structures as the porous matrix to prepare composite phase change materials(PCMs),and investigated their photo-thermal conversion performance and application in battery thermal management.Multiple structure graphite minerals,including microcrystalline graphite(MG),scale graphite(SG),and expanded graphite(EG)were used as porous matrix,while stearic acid(SA)acts as the phase change material.The vacuum impregnation method was applied to prepare SA/MG,SA/SG,SA/EG,and SA/MG1,and SA/EG1was/were prepared by the ethyl alcohol method.Results show that the thermal conductivities of all composite phase change materials were 10.82 to 22.06 times higher than that of the pure SA.Thermogravimetric(TG)analysis showed that the loadages of SA were 43.61%,18.74%,and 92.66%for SA/MG,SA/SG,and SA/EG respectively.The load rates of SA were 18.98%and 18.88%for SA/MG1 and SA/EG1,respectively.For the 3 types of graphite materials of different dimensions,the BET(Brunauer,Emmett,and Teller)surface area determines the maximum load of SA.The Fourier-transform infrared(FTIR)and X-ray diffraction(XRD)results indicated that there was good compatibility between the SA and the supports.The SA/EG1 has better thermophysical properties in heat energy storage and release process.The thermal infrared images show that SA/EG1 has higher sensitivity to the temperature changes.SA/EG1 has better photo-heat conversion performance than SA/SG and SA/MG1 attributed to the multilayer structure of EG.SA/EG has better thermal management performance in the Li-ion batteries discharge process.展开更多
A microwave-assisted heating approach was developed to fabricate SnO2·TiO2 nano-composite in an aqueoas sohaion of sulphuric acid in the presence of SnO2 nano-powder and titanium sulfate. Powder X-ray diffraction...A microwave-assisted heating approach was developed to fabricate SnO2·TiO2 nano-composite in an aqueoas sohaion of sulphuric acid in the presence of SnO2 nano-powder and titanium sulfate. Powder X-ray diffraction （ XRD ） pattern indicates that the products were a composite with both of anatase-type TiO2 and tetrahedrul SnO2. The prnducts were also characterized by transmission electron microscolry （ TEM ）, photoluminescence （PL） spectra. The photo-catalytic property of the as-prepared sample has ulso been studied. The result indicates that the as-prepared sample is a good photo-catadyst.展开更多
采用水热法制备PbTe微晶,研究水热法合成PbTe微晶工艺过程中碲源、反应时间、反应温度、碱加入量、还原剂及表面活性剂等对PbTe微晶形貌的影响,分别采用X射线衍射(X-ray diffraction,XRD)和扫描电镜(scanning electron microscope,SEM)...采用水热法制备PbTe微晶,研究水热法合成PbTe微晶工艺过程中碲源、反应时间、反应温度、碱加入量、还原剂及表面活性剂等对PbTe微晶形貌的影响,分别采用X射线衍射(X-ray diffraction,XRD)和扫描电镜(scanning electron microscope,SEM)对制备的PbTe进行表征.结果表明,控制不同的合成工艺可制备得到立方体、花状和树突状等多种形貌的PbTe微晶.展开更多
文摘Authors produced rapidly solidified T15 high speed steel powders by high pressure(5~ 6MPa) N_a atomization and liquid N_2 cooling,observed and analyzed the morphology and structure of the powders;at the same time,prepared bulk microcrystalline T15 high speed steel materials by hot extruding or HIPing and hot rolling of the powders,observed and measured the microstructure and performance of the bulk materials.It was shown that rapid solidification may change the solidification characteristics and structure of T15 high speed steel powder and improve the qualities and properties of T15 high speed steel materials.
基金supported by the National Natural Science Foundation of China(Nos.52274252 and 51874047)the Special Fund for the Construction of Innovative Provinces in Hunan Province(Nos.2020RC3038 and 2022WK4004)+1 种基金the Changsha City Fund for Distinguished and Innovative Young Scholars(No.kq1802007)the Key Science and Technology Project of Changsha City(No.kq2102005).
文摘This paper used 3 types of graphite with different physical structures as the porous matrix to prepare composite phase change materials(PCMs),and investigated their photo-thermal conversion performance and application in battery thermal management.Multiple structure graphite minerals,including microcrystalline graphite(MG),scale graphite(SG),and expanded graphite(EG)were used as porous matrix,while stearic acid(SA)acts as the phase change material.The vacuum impregnation method was applied to prepare SA/MG,SA/SG,SA/EG,and SA/MG1,and SA/EG1was/were prepared by the ethyl alcohol method.Results show that the thermal conductivities of all composite phase change materials were 10.82 to 22.06 times higher than that of the pure SA.Thermogravimetric(TG)analysis showed that the loadages of SA were 43.61%,18.74%,and 92.66%for SA/MG,SA/SG,and SA/EG respectively.The load rates of SA were 18.98%and 18.88%for SA/MG1 and SA/EG1,respectively.For the 3 types of graphite materials of different dimensions,the BET(Brunauer,Emmett,and Teller)surface area determines the maximum load of SA.The Fourier-transform infrared(FTIR)and X-ray diffraction(XRD)results indicated that there was good compatibility between the SA and the supports.The SA/EG1 has better thermophysical properties in heat energy storage and release process.The thermal infrared images show that SA/EG1 has higher sensitivity to the temperature changes.SA/EG1 has better photo-heat conversion performance than SA/SG and SA/MG1 attributed to the multilayer structure of EG.SA/EG has better thermal management performance in the Li-ion batteries discharge process.
文摘A microwave-assisted heating approach was developed to fabricate SnO2·TiO2 nano-composite in an aqueoas sohaion of sulphuric acid in the presence of SnO2 nano-powder and titanium sulfate. Powder X-ray diffraction （ XRD ） pattern indicates that the products were a composite with both of anatase-type TiO2 and tetrahedrul SnO2. The prnducts were also characterized by transmission electron microscolry （ TEM ）, photoluminescence （PL） spectra. The photo-catalytic property of the as-prepared sample has ulso been studied. The result indicates that the as-prepared sample is a good photo-catadyst.
文摘采用水热法制备PbTe微晶,研究水热法合成PbTe微晶工艺过程中碲源、反应时间、反应温度、碱加入量、还原剂及表面活性剂等对PbTe微晶形貌的影响,分别采用X射线衍射(X-ray diffraction,XRD)和扫描电镜(scanning electron microscope,SEM)对制备的PbTe进行表征.结果表明,控制不同的合成工艺可制备得到立方体、花状和树突状等多种形貌的PbTe微晶.
