Fine tailoring the shape of nanosheets is still a big challenge as the difficult synthesis for highly controlled ultrathin nanosheets.Here we report a facile strategy for tailoring the shape of ultra-thin NdF_(3) nano...Fine tailoring the shape of nanosheets is still a big challenge as the difficult synthesis for highly controlled ultrathin nanosheets.Here we report a facile strategy for tailoring the shape of ultra-thin NdF_(3) nanosheets via a hot injection method.In this method,NdF_(3) nanosheets with only about 2 nm in thickness synthesized first via a hot injection method.The shape of the NdF_(3) nanosheets was able to be tailored from flower-like to the round or the triangular shapes simply by decreasing the reaction temperature from 300℃to 280℃or 260℃.The driven force of the NdF_(3) nanosheets’shape tailoring by the temperature could be that a lower crystal growth rate will guarantee the more stable facets exposed at lower temperature,while under the condition of slow precursor injection,a higher temperature will lead to a further decrease in the crystal growth rate.This shape control method of NdF_(3) nanosheets is highly robust,which could be promoted to other materials.展开更多
By exploring the reasons leading to problems in university-enterprise cooperation,the paper explains the collaboration necessity in talents training between demonstrative software school and enterprises,puts forward c...By exploring the reasons leading to problems in university-enterprise cooperation,the paper explains the collaboration necessity in talents training between demonstrative software school and enterprises,puts forward conventional solutions and probes into the feasible modes of introducing resources from different channels.In addition,analysis is also made into possible stages in which problems might arise.展开更多
Auxetic materials are cellular materials with a unique property of negative Poisson’s ratio.The auxeticity and performance of these metamaterials utterly depend on the geometrical parameters and loading direction.For...Auxetic materials are cellular materials with a unique property of negative Poisson’s ratio.The auxeticity and performance of these metamaterials utterly depend on the geometrical parameters and loading direction.For the first time,the quasi-static uniaxial compression performance of fused filament fabricated re-entrant diamond auxetic metamaterial is evaluated in the x-direction(in-plane)and z-direction(out-of-plane).The most commonly used thermoplastic feedstock,Acrylonitrile butadiene styrene,is considered a material of choice.The effect of influential geometrical parameters of the re-entrant diamond structure and printing parameter is systematically studied using Taguchi’s design of experiments.Grey-based multi-objective optimisation technique has been adopted to arrive at the optimal structure.Efforts are made to improve the stiffness and strength of the structure with fibre reinforcements.Micro glass fibre reinforcements have enhanced specific strength and stiffness in both in-plane and out-ofplane directions.A sevenfold and thirteen times increase in specific strength and energy absorption is evident for glass fibre-reinforced structures in out-of-plane directions compared to in-plane ones.Proper tuning of geometrical parameters of the re-entrant diamond structure can result in a Poisson’s ratio of up to-3.49 when tested in the x-direction.The parametric study has illustrated the tailorability of the structure according to the application requirements.The statistical study has signified each considered parameter’s contribution to the compression performance characteristics of the 3D printed re-entrant diamond auxetic metamaterial.展开更多
The typical method for preparing the porous carbon used in supercapacitors(SCs)is time-consuming and energy-intensive.We report a fast and efficient route to synthesize and tailor the structure of porous carbon by a J...The typical method for preparing the porous carbon used in supercapacitors(SCs)is time-consuming and energy-intensive.We report a fast and efficient route to synthesize and tailor the structure of porous carbon by a Joule heating technique(JHT)using phenolic resin and precursors.During the JHT process,the time and energy needed are both significantly reduced because the precursor is heated to the target temperature at a rate of 1100 K/s,so the porous carbon is formed with the release of small molecules and the etching of the substrate by K_(2)CO_(3).JHT has a higher energy efficiency than traditional carbonization methods in a tube furnace and allows for precise control of the pyrolysis process,thus achieving better control of the material’s structure and properties.Samples obtained by JHT contain abundant pores and a large specific surface area(1652.7 m^(2)/g),which give an excellent specific capacitance of 476.0 F/g and rate capability(75.1%capacitance retention at 64.0 A/g in an aqueous alkaline electrolyte).Furthermore,in electrolytes of 17.0 mol/kg NaClO_(4)(water-in-salt)and 1.0 mol/L TEABF4/AN,the symmetric SCs have a maximum energy density of 33.3 and 50.8 Wh/kg at power densities of 220.4 and 376.4 W/kg,respectively.The cells also have good long-term stability,with a nearly 100%Coulombic efficiency,and a capacitance retention of 93.1%in a water-in-salt electrolyte after 10000 cycles,and 88.9%in an organic electrolyte after 8000 cycles.This study shows that JHT has the potential to serve as an ultra-fast method to prepare porous carbons for energy storage.展开更多
文摘Fine tailoring the shape of nanosheets is still a big challenge as the difficult synthesis for highly controlled ultrathin nanosheets.Here we report a facile strategy for tailoring the shape of ultra-thin NdF_(3) nanosheets via a hot injection method.In this method,NdF_(3) nanosheets with only about 2 nm in thickness synthesized first via a hot injection method.The shape of the NdF_(3) nanosheets was able to be tailored from flower-like to the round or the triangular shapes simply by decreasing the reaction temperature from 300℃to 280℃or 260℃.The driven force of the NdF_(3) nanosheets’shape tailoring by the temperature could be that a lower crystal growth rate will guarantee the more stable facets exposed at lower temperature,while under the condition of slow precursor injection,a higher temperature will lead to a further decrease in the crystal growth rate.This shape control method of NdF_(3) nanosheets is highly robust,which could be promoted to other materials.
文摘By exploring the reasons leading to problems in university-enterprise cooperation,the paper explains the collaboration necessity in talents training between demonstrative software school and enterprises,puts forward conventional solutions and probes into the feasible modes of introducing resources from different channels.In addition,analysis is also made into possible stages in which problems might arise.
文摘Auxetic materials are cellular materials with a unique property of negative Poisson’s ratio.The auxeticity and performance of these metamaterials utterly depend on the geometrical parameters and loading direction.For the first time,the quasi-static uniaxial compression performance of fused filament fabricated re-entrant diamond auxetic metamaterial is evaluated in the x-direction(in-plane)and z-direction(out-of-plane).The most commonly used thermoplastic feedstock,Acrylonitrile butadiene styrene,is considered a material of choice.The effect of influential geometrical parameters of the re-entrant diamond structure and printing parameter is systematically studied using Taguchi’s design of experiments.Grey-based multi-objective optimisation technique has been adopted to arrive at the optimal structure.Efforts are made to improve the stiffness and strength of the structure with fibre reinforcements.Micro glass fibre reinforcements have enhanced specific strength and stiffness in both in-plane and out-ofplane directions.A sevenfold and thirteen times increase in specific strength and energy absorption is evident for glass fibre-reinforced structures in out-of-plane directions compared to in-plane ones.Proper tuning of geometrical parameters of the re-entrant diamond structure can result in a Poisson’s ratio of up to-3.49 when tested in the x-direction.The parametric study has illustrated the tailorability of the structure according to the application requirements.The statistical study has signified each considered parameter’s contribution to the compression performance characteristics of the 3D printed re-entrant diamond auxetic metamaterial.
文摘The typical method for preparing the porous carbon used in supercapacitors(SCs)is time-consuming and energy-intensive.We report a fast and efficient route to synthesize and tailor the structure of porous carbon by a Joule heating technique(JHT)using phenolic resin and precursors.During the JHT process,the time and energy needed are both significantly reduced because the precursor is heated to the target temperature at a rate of 1100 K/s,so the porous carbon is formed with the release of small molecules and the etching of the substrate by K_(2)CO_(3).JHT has a higher energy efficiency than traditional carbonization methods in a tube furnace and allows for precise control of the pyrolysis process,thus achieving better control of the material’s structure and properties.Samples obtained by JHT contain abundant pores and a large specific surface area(1652.7 m^(2)/g),which give an excellent specific capacitance of 476.0 F/g and rate capability(75.1%capacitance retention at 64.0 A/g in an aqueous alkaline electrolyte).Furthermore,in electrolytes of 17.0 mol/kg NaClO_(4)(water-in-salt)and 1.0 mol/L TEABF4/AN,the symmetric SCs have a maximum energy density of 33.3 and 50.8 Wh/kg at power densities of 220.4 and 376.4 W/kg,respectively.The cells also have good long-term stability,with a nearly 100%Coulombic efficiency,and a capacitance retention of 93.1%in a water-in-salt electrolyte after 10000 cycles,and 88.9%in an organic electrolyte after 8000 cycles.This study shows that JHT has the potential to serve as an ultra-fast method to prepare porous carbons for energy storage.
