The results of experimental study of nanoscale intermetallic formation in surface layer of a metal target at ion implantation are presented. To increase the thickness of the ion implanted surface layer the high intens...The results of experimental study of nanoscale intermetallic formation in surface layer of a metal target at ion implantation are presented. To increase the thickness of the ion implanted surface layer the high intensive ion implantation is used. Compared with the ordinary ion implantation, the high intensive ion implantation allows a much thicker modified surface layer. Pure polycrystalline nickel was chosen as a target. Nickel samples were irradiated with Al ions on the vacuum-arc ion beam and plasma flow source 'Raduga-5'. It was shown that at the high intensity ion implantation the fine dispersed particles of Ni3AI, NiAl intermetallic compounds and solid solution Al in Ni are formed in the nickel surface layer of 200 nm and thicker. The formation of phases takes place in complete correspondence with the Ni-AI phase diagram.展开更多
Research activities in Japan relevant to particle beam inertial fusion are briefly reviewed.These activities can be ascended to the 1980s.During the past three decades,significant progress in particle beam fusion,puls...Research activities in Japan relevant to particle beam inertial fusion are briefly reviewed.These activities can be ascended to the 1980s.During the past three decades,significant progress in particle beam fusion,pulsed power systems,accelerator schemes for intense beams,target physics,and high-energy-density physics research has been made by a number of research groups at universities and accelerator facilities in Japan.High-flux ions have been extracted from laser ablation plasmas.Controllability of the ion velocity distribution in the plasma by an axial magnetic and/or electric field has realized a stable high-flux low-emittance beam injector.Beam dynamics have been studied both theoretically and experimentally.The efforts have been concentrated on the beam behavior during the final compression stage of intense beam accelerators.A novel accelerator scheme based on a repetitive induction modulator has been proposed as a cost-effective particle-beam driver scheme.Beam-plasma interaction and pulse-powered plasma experiments have been investigated as relevant studies of particle beam inertial fusion.An irradiation method to mitigate the instability in imploding target has been proposed using oscillating heavy-ion beams.The new irradiation method has reopened the exploration of direct drive scheme of particle beam fusion.展开更多
Biomass‐derived carbon is a promising electrode material in energy storage devices.However,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a challenge.In this ...Biomass‐derived carbon is a promising electrode material in energy storage devices.However,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a challenge.In this research,we propose a“self‐assembly‐template”method to prepare B,N codoped porous carbon(BN‐C)with a nanosandwich structure and abundant pyridinic N‐B species.The nanosandwich structure can increase powder density and cycle stability by constructing a stable solid electrolyte interphase film,shortening the Li^(+) diffusion pathway,and accommodating volume expansion during repeated charging/discharging.The abundant pyridinic N‐B species can simultaneously promote the adsorption/desorption of Li^(+)/PF_(6)^(−) and reduce the diffusion barrier.The BN‐C electrode showed a high lithium‐ion storage capacity of above 1140 mAh g^(−1) at 0.05 A g^(−1) and superior stability(96.5% retained after 2000 cycles).Moreover,owing to the synergistic effect of the nanosandwich structure and pyridinic N‐B species,the assembled symmetrical BN‐C//BN‐C full cell shows a high energy density of 234.7Wh kg^(−1),high power density of 39.38 kW kg−1,and excellent cycling stability,superior to most of the other cells reported in the literature.As the density functional theory simulation demonstrated,pyridinic N‐B shows enhanced adsorption activity for Li^(+) and PF_(6)^(−),which promotes an increase in the capacity of the anode and cathode,respectively.Meanwhile,the relatively lower diffusion barrier of pyridinic N‐B promotes Li^(+) migration,resulting in good rate performance.Therefore,this study provides a new approach for the synergistic modulation of a nanostructure and an active site simultaneously to fabricate the carbon electrode material in energy storage devices.展开更多
We examine the evolution of quark-gluon plasma（QGP） droplets with viscous hydrodynamics and analyze the pion transverse-momentum spectrum, elliptic flow, and Hanbury-Brown-Twiss（HBT） interferometry in a granular s...We examine the evolution of quark-gluon plasma（QGP） droplets with viscous hydrodynamics and analyze the pion transverse-momentum spectrum, elliptic flow, and Hanbury-Brown-Twiss（HBT） interferometry in a granular source model consisting of viscous QGP droplets. The shear viscosity of the QGP droplet speeds up and slows down the droplet evolution in the central and peripheral regions of the droplet, respectively. The effect of the bulk viscosity on the evolution is negligible. Although there are viscous effects on the droplet evolution, the pion momentum spectrum and elliptic flow change little for granular sources with and without viscosity. On the other hand,the influence of viscosity on HBT radius Rout is considerable. It makes Rout decrease in the granular source model.We determine the model parameters of granular sources using the experimental data of pion transverse-momentum spectrum, elliptic flow, and HBT radii together, and investigate the effects of viscosity on the model parameters. The results indicate that the granular source model may reproduce the experimental data of pion transverse-momentum spectrum, elliptic flow, and HBT radii in heavy-ion collisions of Au-Au at√s（NN）=200 GeV and Pb-Pb at√s（NN） =2.76 Te V in different centrality intervals. The viscosity of the droplet leads to an increase in the initial droplet radius and a decrease of the source shell parameter in the granular source model.展开更多
通过超声表面滚压处理制备出具有梯度纳米结构表层的Dievar模具钢试样。在滚压试样和未滚压试样表面进行高能离子注渗(High energy ion implantation,HEII)工艺优化试验,制备出高能离子注渗碳化钨层,并从微观组织结构、成分、硬度和高...通过超声表面滚压处理制备出具有梯度纳米结构表层的Dievar模具钢试样。在滚压试样和未滚压试样表面进行高能离子注渗(High energy ion implantation,HEII)工艺优化试验,制备出高能离子注渗碳化钨层,并从微观组织结构、成分、硬度和高温摩擦磨损性能等方面研究表面纳米化对于高能离子注渗碳化钨性能的影响。结果表明:与HEII试样相比,USRP+HEII试样的梯度纳米结构表层明显增强了高能离子注渗碳化钨的效果。相对于HEII试样,USRP+HEII试样的表面组织更加致密均匀,其注渗层深度提高了约27%;USRP+HEII试样的表面硬度为944.9 HV,分别较原始母材硬度和HEII试样表面硬度提高了约373%和27%;USRP+HEII试样的平均摩擦因数和体积磨损量在不同温度条件下低于HEII试样,说明USRP+HEII试样具有更加优良的抗高温磨损性能。展开更多
文摘The results of experimental study of nanoscale intermetallic formation in surface layer of a metal target at ion implantation are presented. To increase the thickness of the ion implanted surface layer the high intensive ion implantation is used. Compared with the ordinary ion implantation, the high intensive ion implantation allows a much thicker modified surface layer. Pure polycrystalline nickel was chosen as a target. Nickel samples were irradiated with Al ions on the vacuum-arc ion beam and plasma flow source 'Raduga-5'. It was shown that at the high intensity ion implantation the fine dispersed particles of Ni3AI, NiAl intermetallic compounds and solid solution Al in Ni are formed in the nickel surface layer of 200 nm and thicker. The formation of phases takes place in complete correspondence with the Ni-AI phase diagram.
文摘Research activities in Japan relevant to particle beam inertial fusion are briefly reviewed.These activities can be ascended to the 1980s.During the past three decades,significant progress in particle beam fusion,pulsed power systems,accelerator schemes for intense beams,target physics,and high-energy-density physics research has been made by a number of research groups at universities and accelerator facilities in Japan.High-flux ions have been extracted from laser ablation plasmas.Controllability of the ion velocity distribution in the plasma by an axial magnetic and/or electric field has realized a stable high-flux low-emittance beam injector.Beam dynamics have been studied both theoretically and experimentally.The efforts have been concentrated on the beam behavior during the final compression stage of intense beam accelerators.A novel accelerator scheme based on a repetitive induction modulator has been proposed as a cost-effective particle-beam driver scheme.Beam-plasma interaction and pulse-powered plasma experiments have been investigated as relevant studies of particle beam inertial fusion.An irradiation method to mitigate the instability in imploding target has been proposed using oscillating heavy-ion beams.The new irradiation method has reopened the exploration of direct drive scheme of particle beam fusion.
基金Jiangsu Key Lab of Biomass Energy and Material,Grant/Award Number:JSBEMS‐202101National Natural Science Foundation of China,Grant/Award Numbers:51902162,51902162+4 种基金National Key R&D Program of China,Grant/Award Number:2022YFB4201904Foundation of Jiangsu Key Lab of Biomass Energy and Material,Grant/Award Number:JSBEM‐S‐202101National Key R&D Program,Grant/Award Number:2022YFB4201904Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest Resources,the International Innovation Center for Forest Chemicals and Materialsanjing Forestry University。
文摘Biomass‐derived carbon is a promising electrode material in energy storage devices.However,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a challenge.In this research,we propose a“self‐assembly‐template”method to prepare B,N codoped porous carbon(BN‐C)with a nanosandwich structure and abundant pyridinic N‐B species.The nanosandwich structure can increase powder density and cycle stability by constructing a stable solid electrolyte interphase film,shortening the Li^(+) diffusion pathway,and accommodating volume expansion during repeated charging/discharging.The abundant pyridinic N‐B species can simultaneously promote the adsorption/desorption of Li^(+)/PF_(6)^(−) and reduce the diffusion barrier.The BN‐C electrode showed a high lithium‐ion storage capacity of above 1140 mAh g^(−1) at 0.05 A g^(−1) and superior stability(96.5% retained after 2000 cycles).Moreover,owing to the synergistic effect of the nanosandwich structure and pyridinic N‐B species,the assembled symmetrical BN‐C//BN‐C full cell shows a high energy density of 234.7Wh kg^(−1),high power density of 39.38 kW kg−1,and excellent cycling stability,superior to most of the other cells reported in the literature.As the density functional theory simulation demonstrated,pyridinic N‐B shows enhanced adsorption activity for Li^(+) and PF_(6)^(−),which promotes an increase in the capacity of the anode and cathode,respectively.Meanwhile,the relatively lower diffusion barrier of pyridinic N‐B promotes Li^(+) migration,resulting in good rate performance.Therefore,this study provides a new approach for the synergistic modulation of a nanostructure and an active site simultaneously to fabricate the carbon electrode material in energy storage devices.
基金Supported by National Natural Science Foundation of China(11675034,11275037)
文摘We examine the evolution of quark-gluon plasma（QGP） droplets with viscous hydrodynamics and analyze the pion transverse-momentum spectrum, elliptic flow, and Hanbury-Brown-Twiss（HBT） interferometry in a granular source model consisting of viscous QGP droplets. The shear viscosity of the QGP droplet speeds up and slows down the droplet evolution in the central and peripheral regions of the droplet, respectively. The effect of the bulk viscosity on the evolution is negligible. Although there are viscous effects on the droplet evolution, the pion momentum spectrum and elliptic flow change little for granular sources with and without viscosity. On the other hand,the influence of viscosity on HBT radius Rout is considerable. It makes Rout decrease in the granular source model.We determine the model parameters of granular sources using the experimental data of pion transverse-momentum spectrum, elliptic flow, and HBT radii together, and investigate the effects of viscosity on the model parameters. The results indicate that the granular source model may reproduce the experimental data of pion transverse-momentum spectrum, elliptic flow, and HBT radii in heavy-ion collisions of Au-Au at√s（NN）=200 GeV and Pb-Pb at√s（NN） =2.76 Te V in different centrality intervals. The viscosity of the droplet leads to an increase in the initial droplet radius and a decrease of the source shell parameter in the granular source model.
文摘通过超声表面滚压处理制备出具有梯度纳米结构表层的Dievar模具钢试样。在滚压试样和未滚压试样表面进行高能离子注渗(High energy ion implantation,HEII)工艺优化试验,制备出高能离子注渗碳化钨层,并从微观组织结构、成分、硬度和高温摩擦磨损性能等方面研究表面纳米化对于高能离子注渗碳化钨性能的影响。结果表明:与HEII试样相比,USRP+HEII试样的梯度纳米结构表层明显增强了高能离子注渗碳化钨的效果。相对于HEII试样,USRP+HEII试样的表面组织更加致密均匀,其注渗层深度提高了约27%;USRP+HEII试样的表面硬度为944.9 HV,分别较原始母材硬度和HEII试样表面硬度提高了约373%和27%;USRP+HEII试样的平均摩擦因数和体积磨损量在不同温度条件下低于HEII试样,说明USRP+HEII试样具有更加优良的抗高温磨损性能。
