3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational acc...3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational accuracy and efficiency,the optimal choices of numerical parameters and algorithms in FE modelling were determined.The formation mechanisms of cross-section distortion and springback were revealed.The effects of pre-stretching,post-stretching,friction,and the addition of internal fillers on forming quality were investigated.The results show that the stress state of profile in stretch-bending is uniaxial with only a circumferential stress.The stress distribution along the length direction of profile is non-uniform and the maximum tensile stress is located at a certain distance away from the center of profile.As aluminum profile is gradually attached to bending die,the distribution characteristic of cross-section distortion along the length direction of profile changes from V-shape to W-shape.After unloading the forming tools,cross-section distortion decreases obviously due to the stress relaxation,with a maximum distortion difference of 13%before and after unloading.As pre-stretching and post-stretching forces increase,cross-section distortion increases gradually,while springback first decreases and then remains unchanged.With increasing friction between bending die and profile,cross-section distortion slightly decreases,while springback increases.Cross-section distortion decreases by 83%with adding PVC fillers into the cavities of profile,while springback increases by 192.2%.展开更多
Double differential cross-sections of first Born estimation for ionization of hydrogenic 2S state by electrons are assessed for various kinematics situations in the asymmetric coplanar geometry. A final state wave fun...Double differential cross-sections of first Born estimation for ionization of hydrogenic 2S state by electrons are assessed for various kinematics situations in the asymmetric coplanar geometry. A final state wave function of multiple scattering theory is followed in this study. The present outcomes are compared with those of hydrogenic ground state, 2P state and ground state experimental results. Obtained findings show a good qualitative agreement with existing results.展开更多
With exhaustion of fossil fuels and the deterioration of global environment,widespread and intensive researches have been concentrated on clean and sustainable alternative energy sources,such as metal-air batteries[1]...With exhaustion of fossil fuels and the deterioration of global environment,widespread and intensive researches have been concentrated on clean and sustainable alternative energy sources,such as metal-air batteries[1],fuel cells[2]and water splitting devices[3].Electrocatalytic oxidation of water to O2(oxygen evolution reaction,OER)is a vital chemical process involved in energy storage and conversion from renewable sources in form of molecular fuels such as H2 via water electrolysis,which has attracted a great amount of research efforts in the past few years[4,5].Nowadays,RuO2 and IrO2 are widely used as typical excellent OER electrocatalysts.However,their high-cost and scarce nature restricts the broadly commercial application of those materials[6,7].Hence,there is an urgent demand to develop low cost,highly efficient,and superb stable OER catalysts.展开更多
Flexible aqueous Ni//Zn batteries have attracted much attention as promising candidates for energy storage in the field of flexible electronics.However,the Ni-based cathodes still face the challenges of poor conductiv...Flexible aqueous Ni//Zn batteries have attracted much attention as promising candidates for energy storage in the field of flexible electronics.However,the Ni-based cathodes still face the challenges of poor conductivity,confined charge/mass transfer,and non-flexibility.In this work,we designed a hollow tubular structure consisting of a conductive silver nanowire (Ag NW) wrapped by active Ni Co layered double hydroxide (LDH),for enhancing the electrical conductivity,improving the charge/mass transfer kinetics,and facilitating the ion penetration.By optimizing the contents of Ni,Co and Ag NW,the Ni_(4)Co LDH@Ag_(1.5)NW composite shows a maximum specific capacity of 115.83 m Ah g^(-1)at 0.1 A g^(-1)measured in a two-electrode system.Highlightingly,the flexible aqueous Ni//Zn battery assembled by Ni_(4)Co LDH@Ag_(1.5)NW interwoven with multi-walled carbon nanotube cathode and Zn foil anode realizes a high power density of 160μW cm^(-2)at the energy density of 23.14μWh cm^(-2),which is superior compared with those of oxide/hydroxide based devices and even higher than those of many carbon-based supercapacitors,showing its promising potentials for flexible energy storage applications.展开更多
The ternary transitional metal oxide NiCo_2O_4 is a promising anode material for sodium ion batteries due to its high theoretical capacity and superior electrical conductivity. However, its sodium storage capability i...The ternary transitional metal oxide NiCo_2O_4 is a promising anode material for sodium ion batteries due to its high theoretical capacity and superior electrical conductivity. However, its sodium storage capability is severely limited by the sluggish sodiation/desodiation reaction kinetics. Herein, NiCo_2O_4 double-shelled hollow spheres were synthesized via a microwave-assisted, fast solvothermal synthetic procedure in a mixture of isopropanol and glycerol, followed by annealing. Isopropanol played a vital role in the precipitation of nickel and cobalt,and the shrinkage of the glycerol quasi-emulsion under heat treatment was responsible for the formation of the double-shelled nanostructure. The as-synthesized productwas tested as an anode material in a sodium ion battery,was found to exhibit a high reversible specific capacity of 511 m Ahg^(-1) at 100 m Ag^(-1), and deliver high capacity retention after 100 cycles.展开更多
Green hydrogen production via seawater electrolysis holds a great promise for carbon-neutral energy production. However, the development of efficient and low-cost bifunctional electrocatalysts for seawater electrolysi...Green hydrogen production via seawater electrolysis holds a great promise for carbon-neutral energy production. However, the development of efficient and low-cost bifunctional electrocatalysts for seawater electrolysis at an industrial level remains a significant challenge. Herein, we report a facile approach based on one-dimensional (1D) cobalt carbonate hydroxide (CCH) nanoneedles (NNs) as skeleton and zeolitic imidazolate framework-67 (ZIF-67) as a sacrificial template to construct a self-supported NiCo layered double hydroxide (NiCo LDH) heterostructure nanocage (CCH@NiCo LDH) anchoring on the carbon felt (CF). The NiCo LDHs have hollow features, consisting of ultrathin layered hydroxide nanosheets. Benefiting from the structural advantages, unique carbon substrate and desirable composition, three-dimensional (3D) NiCo LDH nanocages exhibit superior performance as a bifunctional catalyst for overall seawater splitting at an industrial level and good corrosion resistance in alkaline media. In the alkaline seawater (1 M KOH + 0.5 M NaCl), it exhibits low overpotentials of 356 mV for hydrogen evolution reaction (HER) and 433 mV for oxygen evolution reaction (OER) at 400 mA·cm^(−2), much better than most of reported non-noble metal catalysts. Consequently, the obtained CF electrode loading of CCH@NiCo LDH exhibits outstanding performance as anodes and cathodes for overall alkaline seawater splitting, with remarkably low cell voltages of 1.56 and 1.89 V at current densities of 10 and 400 mA·cm^(−2), respectively. Moreover, the robust stability of 100 h is also demonstrated at above 200 mA·cm^(−2) in alkaline seawater. Our present work demonstrates significant potential for constructing effective cost-efficient and non-noble-metal bifunctional electrocatalyst and electrode for industrial seawater splitting.展开更多
基金the National Natural Science Foundation of China(Nos.52005244,U20A20275)the Natural Science Foundation of Hunan Province,China(Nos.2021JJ30573,2023JJ60193)the Open Fund of State Key Laboratory of Advanced Design and Manufacture for Vehicle Body,China(No.31715011)。
文摘3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational accuracy and efficiency,the optimal choices of numerical parameters and algorithms in FE modelling were determined.The formation mechanisms of cross-section distortion and springback were revealed.The effects of pre-stretching,post-stretching,friction,and the addition of internal fillers on forming quality were investigated.The results show that the stress state of profile in stretch-bending is uniaxial with only a circumferential stress.The stress distribution along the length direction of profile is non-uniform and the maximum tensile stress is located at a certain distance away from the center of profile.As aluminum profile is gradually attached to bending die,the distribution characteristic of cross-section distortion along the length direction of profile changes from V-shape to W-shape.After unloading the forming tools,cross-section distortion decreases obviously due to the stress relaxation,with a maximum distortion difference of 13%before and after unloading.As pre-stretching and post-stretching forces increase,cross-section distortion increases gradually,while springback first decreases and then remains unchanged.With increasing friction between bending die and profile,cross-section distortion slightly decreases,while springback increases.Cross-section distortion decreases by 83%with adding PVC fillers into the cavities of profile,while springback increases by 192.2%.
文摘Double differential cross-sections of first Born estimation for ionization of hydrogenic 2S state by electrons are assessed for various kinematics situations in the asymmetric coplanar geometry. A final state wave function of multiple scattering theory is followed in this study. The present outcomes are compared with those of hydrogenic ground state, 2P state and ground state experimental results. Obtained findings show a good qualitative agreement with existing results.
基金financially supported by the National Natural Science Foundation of China(U1707603,21521005,21975013,21901017)the National Key Research and Development Program of China(2017YFA0206500,2018YFA0702000)+2 种基金Beijing Natural Science Foundation(2172042)PetroChina Innovation Foundationthe Fundamental Research Funds for the Central Universities。
文摘With exhaustion of fossil fuels and the deterioration of global environment,widespread and intensive researches have been concentrated on clean and sustainable alternative energy sources,such as metal-air batteries[1],fuel cells[2]and water splitting devices[3].Electrocatalytic oxidation of water to O2(oxygen evolution reaction,OER)is a vital chemical process involved in energy storage and conversion from renewable sources in form of molecular fuels such as H2 via water electrolysis,which has attracted a great amount of research efforts in the past few years[4,5].Nowadays,RuO2 and IrO2 are widely used as typical excellent OER electrocatalysts.However,their high-cost and scarce nature restricts the broadly commercial application of those materials[6,7].Hence,there is an urgent demand to develop low cost,highly efficient,and superb stable OER catalysts.
基金sponsored by the National Natural Science Foundation of China(61804054)the Natural Science Foundation of Shanghai(18ZR1410400)+2 种基金the Shanghai Sailing Program(17YF1403300)the Shanghai Aerospace Science and Technology Innovation Fundation(SISP2018)the Shanghai Aerospace Science and Technology Innovation Fund(SAST2019-067)。
文摘Flexible aqueous Ni//Zn batteries have attracted much attention as promising candidates for energy storage in the field of flexible electronics.However,the Ni-based cathodes still face the challenges of poor conductivity,confined charge/mass transfer,and non-flexibility.In this work,we designed a hollow tubular structure consisting of a conductive silver nanowire (Ag NW) wrapped by active Ni Co layered double hydroxide (LDH),for enhancing the electrical conductivity,improving the charge/mass transfer kinetics,and facilitating the ion penetration.By optimizing the contents of Ni,Co and Ag NW,the Ni_(4)Co LDH@Ag_(1.5)NW composite shows a maximum specific capacity of 115.83 m Ah g^(-1)at 0.1 A g^(-1)measured in a two-electrode system.Highlightingly,the flexible aqueous Ni//Zn battery assembled by Ni_(4)Co LDH@Ag_(1.5)NW interwoven with multi-walled carbon nanotube cathode and Zn foil anode realizes a high power density of 160μW cm^(-2)at the energy density of 23.14μWh cm^(-2),which is superior compared with those of oxide/hydroxide based devices and even higher than those of many carbon-based supercapacitors,showing its promising potentials for flexible energy storage applications.
基金financially supported by the Science Foundation of Sichuan Province(Grant No.2016FZ0070)the Natural Science Foundation of China(NSFC,201476145)the technical support for Materials Characterization from The Analytical and Testing Center of Sichuan University
文摘The ternary transitional metal oxide NiCo_2O_4 is a promising anode material for sodium ion batteries due to its high theoretical capacity and superior electrical conductivity. However, its sodium storage capability is severely limited by the sluggish sodiation/desodiation reaction kinetics. Herein, NiCo_2O_4 double-shelled hollow spheres were synthesized via a microwave-assisted, fast solvothermal synthetic procedure in a mixture of isopropanol and glycerol, followed by annealing. Isopropanol played a vital role in the precipitation of nickel and cobalt,and the shrinkage of the glycerol quasi-emulsion under heat treatment was responsible for the formation of the double-shelled nanostructure. The as-synthesized productwas tested as an anode material in a sodium ion battery,was found to exhibit a high reversible specific capacity of 511 m Ahg^(-1) at 100 m Ag^(-1), and deliver high capacity retention after 100 cycles.
基金supported by the National Natural Science Foundation of China(Nos.51908408 and 21872104)Natural Science Foundation of Tianjin for Distinguished Young Scholar,China(No.20JCJQJC00150).
文摘Green hydrogen production via seawater electrolysis holds a great promise for carbon-neutral energy production. However, the development of efficient and low-cost bifunctional electrocatalysts for seawater electrolysis at an industrial level remains a significant challenge. Herein, we report a facile approach based on one-dimensional (1D) cobalt carbonate hydroxide (CCH) nanoneedles (NNs) as skeleton and zeolitic imidazolate framework-67 (ZIF-67) as a sacrificial template to construct a self-supported NiCo layered double hydroxide (NiCo LDH) heterostructure nanocage (CCH@NiCo LDH) anchoring on the carbon felt (CF). The NiCo LDHs have hollow features, consisting of ultrathin layered hydroxide nanosheets. Benefiting from the structural advantages, unique carbon substrate and desirable composition, three-dimensional (3D) NiCo LDH nanocages exhibit superior performance as a bifunctional catalyst for overall seawater splitting at an industrial level and good corrosion resistance in alkaline media. In the alkaline seawater (1 M KOH + 0.5 M NaCl), it exhibits low overpotentials of 356 mV for hydrogen evolution reaction (HER) and 433 mV for oxygen evolution reaction (OER) at 400 mA·cm^(−2), much better than most of reported non-noble metal catalysts. Consequently, the obtained CF electrode loading of CCH@NiCo LDH exhibits outstanding performance as anodes and cathodes for overall alkaline seawater splitting, with remarkably low cell voltages of 1.56 and 1.89 V at current densities of 10 and 400 mA·cm^(−2), respectively. Moreover, the robust stability of 100 h is also demonstrated at above 200 mA·cm^(−2) in alkaline seawater. Our present work demonstrates significant potential for constructing effective cost-efficient and non-noble-metal bifunctional electrocatalyst and electrode for industrial seawater splitting.
