Region partition(RP) is the key technique to the finite element parallel computing(FEPC),and its performance has a decisive influence on the entire process of analysis and computation.The performance evaluation index ...Region partition(RP) is the key technique to the finite element parallel computing(FEPC),and its performance has a decisive influence on the entire process of analysis and computation.The performance evaluation index of RP method for the three-dimensional finite element model(FEM) has been given.By taking the electric field of aluminum reduction cell(ARC) as the research object,the performance of two classical RP methods,which are Al-NASRA and NGUYEN partition(ANP) algorithm and the multi-level partition(MLP) method,has been analyzed and compared.The comparison results indicate a sound performance of ANP algorithm,but to large-scale models,the computing time of ANP algorithm increases notably.This is because the ANP algorithm determines only one node based on the minimum weight and just adds the elements connected to the node into the sub-region during each iteration.To obtain the satisfied speed and the precision,an improved dynamic self-adaptive ANP(DSA-ANP) algorithm has been proposed.With consideration of model scale,complexity and sub-RP stage,the improved algorithm adaptively determines the number of nodes and selects those nodes with small enough weight,and then dynamically adds these connected elements.The proposed algorithm has been applied to the finite element analysis(FEA) of the electric field simulation of ARC.Compared with the traditional ANP algorithm,the computational efficiency of the proposed algorithm has been shortened approximately from 260 s to 13 s.This proves the superiority of the improved algorithm on computing time performance.展开更多
Hybrid catalysts based on iron phthalocyanine(FePc)have raised much attention due to their promising applications in electrocatalytic oxygen reduction reaction(ORR).Various hybridization strategies have been developed...Hybrid catalysts based on iron phthalocyanine(FePc)have raised much attention due to their promising applications in electrocatalytic oxygen reduction reaction(ORR).Various hybridization strategies have been developed for improving their activity and durability.However,the influence of different hybridization strategies on their catalytic performance remains unclear.In this study,Fe Pc was effectively distributed on molybdenum disulfide(MoS_(2))forming Fe Pc-based hybrid catalysts,namely Fe Pc-MoS_(2),Fe Pc*-MoS_(2),and Fe Pc-Py-MoS_(2),respectively,to disclose the related influence.Through direct hybridization,the stacked and highly dispersed Fe Pc on MoS_(2)resulted in Fe Pc-MoS_(2),and Fe Pc*-MoS_(2),respectively,in which the substrate and Fe Pc are mainly bound through van der Waals interactions.Through covalent hybridization strategy using pyridyl(Py)as a linker,Fe Pc-Py-MoS_(2)hybrid catalyst was prepared.Experimental and theoretical results disclosed that the linker hybridization of Fe Pc and MoS_(2)facilitated the exposure of Fe-N4 sites,maintained the intrinsic activity of Fe Pc by forming a more dispersed phase and increased the durability via Fe-N bonding,rendering the Fe Pc-Py-MoS_(2)an excellent ORR hybrid catalyst.Compared with van der Waals hybridized Fe Pc-MoS_(2)and Fe Pc*-MoS_(2)in alkaline media,the linker hybridized Fe Pc-Py-MoS_(2)showed an obviously enhanced ORR activity with a half-wave potential(E_(1/2))of 0.88 V vs RHE and an ultralow Tafel slope of 26 m V dec-1.Besides,the Fe Pc-Py-MoS_(2)exhibited a negligible decay of E_(1/2) after 50,000 CV cycles for ORR,showing its superior durability.This work gives us more insight into the influence of different hybrid strategies on Fe Pc catalysts and provides further guidance for the development of highly efficient and durable ORR catalysts.展开更多
“区域综合开发”已成为国内基础设施建设的主要模式。在此模式下,各企业间的竞争不再单纯的是技术和价格的竞争,更多的是考验企业“资源整合、现金为王”的综合能力。基于此,本文对P P P、F+E P C、延迟支付等多种商业模式进行分析,以...“区域综合开发”已成为国内基础设施建设的主要模式。在此模式下,各企业间的竞争不再单纯的是技术和价格的竞争,更多的是考验企业“资源整合、现金为王”的综合能力。基于此,本文对P P P、F+E P C、延迟支付等多种商业模式进行分析,以期推动建设项目商业模式的发展。展开更多
The control of the Kondo effect is of great interest in single-molecule junction due to its potential applications in spin based electronics.Here,we demonstrate that the Kondo effect is reversibly switched on and off ...The control of the Kondo effect is of great interest in single-molecule junction due to its potential applications in spin based electronics.Here,we demonstrate that the Kondo effect is reversibly switched on and off in an iron phthalocyanine(FePc)single-molecule junction by using a superconducting Nb tip.In a scanning tunneling microscope-based Nb-insulator-FePc-Au junction,we achieve a reversible switching between the Kondo dip and inelastic electronic tunneling spectra by simply adjusting the tip-sample distance to tune the tunnel coupling at low temperature.Further approaching the tip leads to the picking up of the molecule to the tip apex,which transfers the geometry of the single-molecule junction into a Nb-FePc-insulator-Au type.As the molecule forms an effective magnetic impurity embedded into the superconducting ground states of the Nb tip,the out-gap Kondo dip switched to an in-gap Yu-Shiba-Rusinov state.Our results open up a new route for manipulating the Kondo effect within a single-molecule junction.展开更多
Improving the separation efficiency of photogenerated carriers and broadening the light absorption range of the photocatalyst are two important factors for improving the performance of the photocatalyst.In this paper,...Improving the separation efficiency of photogenerated carriers and broadening the light absorption range of the photocatalyst are two important factors for improving the performance of the photocatalyst.In this paper,a new and efficient Z-scheme Cd S/iron phthalocyanine(Cd S/Fe Pc)core-shell nanostructure composite material is prepared by a simple solid-phase reaction method.There are two key points in the preparation of composite materials:one is that hydrogen bonding energy is closely connected with Fe Pc,another is that Fe Pc can be uniformly assembled on Cd S nanoparticles.The photocatalytic hydrogen evolution(PHE)of the Cd S/Fe Pc nanocomposite(73.01μmol/h)is 2.6 times higher than that of pure Cd S(26.67μmol/h).In addition,after 4 photocatalytic cycles,the PHE of the Cd S/Fe Pc composite is still 92.3%of the first cycle.There are three reasons for this situation:(1)The Z-scheme heterojunction is formed to improve the separation efficiency of photogenerated carriers;(2)Fe Pc expands the visible light absorption range of Cd S;(3)The large core-shell contact area is favorable for the separation of photo-induced carriers at the interfaces.This research is conducive to the further development of new photocatalytic materials with high efficiency,low cost and simple preparation.展开更多
基金Project(61273187)supported by the National Natural Science Foundation of ChinaProject(61321003)supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China
文摘Region partition(RP) is the key technique to the finite element parallel computing(FEPC),and its performance has a decisive influence on the entire process of analysis and computation.The performance evaluation index of RP method for the three-dimensional finite element model(FEM) has been given.By taking the electric field of aluminum reduction cell(ARC) as the research object,the performance of two classical RP methods,which are Al-NASRA and NGUYEN partition(ANP) algorithm and the multi-level partition(MLP) method,has been analyzed and compared.The comparison results indicate a sound performance of ANP algorithm,but to large-scale models,the computing time of ANP algorithm increases notably.This is because the ANP algorithm determines only one node based on the minimum weight and just adds the elements connected to the node into the sub-region during each iteration.To obtain the satisfied speed and the precision,an improved dynamic self-adaptive ANP(DSA-ANP) algorithm has been proposed.With consideration of model scale,complexity and sub-RP stage,the improved algorithm adaptively determines the number of nodes and selects those nodes with small enough weight,and then dynamically adds these connected elements.The proposed algorithm has been applied to the finite element analysis(FEA) of the electric field simulation of ARC.Compared with the traditional ANP algorithm,the computational efficiency of the proposed algorithm has been shortened approximately from 260 s to 13 s.This proves the superiority of the improved algorithm on computing time performance.
基金financial support from the National Natural Science Foundation of China(51872156,22075163)the National Key Research Program(2020YFC2201103,2020YFA0210702)+1 种基金the China Postdoctoral Science Foundation funded project(2020 M670343)the Shuimu Tsinghua Scholar Program。
文摘Hybrid catalysts based on iron phthalocyanine(FePc)have raised much attention due to their promising applications in electrocatalytic oxygen reduction reaction(ORR).Various hybridization strategies have been developed for improving their activity and durability.However,the influence of different hybridization strategies on their catalytic performance remains unclear.In this study,Fe Pc was effectively distributed on molybdenum disulfide(MoS_(2))forming Fe Pc-based hybrid catalysts,namely Fe Pc-MoS_(2),Fe Pc*-MoS_(2),and Fe Pc-Py-MoS_(2),respectively,to disclose the related influence.Through direct hybridization,the stacked and highly dispersed Fe Pc on MoS_(2)resulted in Fe Pc-MoS_(2),and Fe Pc*-MoS_(2),respectively,in which the substrate and Fe Pc are mainly bound through van der Waals interactions.Through covalent hybridization strategy using pyridyl(Py)as a linker,Fe Pc-Py-MoS_(2)hybrid catalyst was prepared.Experimental and theoretical results disclosed that the linker hybridization of Fe Pc and MoS_(2)facilitated the exposure of Fe-N4 sites,maintained the intrinsic activity of Fe Pc by forming a more dispersed phase and increased the durability via Fe-N bonding,rendering the Fe Pc-Py-MoS_(2)an excellent ORR hybrid catalyst.Compared with van der Waals hybridized Fe Pc-MoS_(2)and Fe Pc*-MoS_(2)in alkaline media,the linker hybridized Fe Pc-Py-MoS_(2)showed an obviously enhanced ORR activity with a half-wave potential(E_(1/2))of 0.88 V vs RHE and an ultralow Tafel slope of 26 m V dec-1.Besides,the Fe Pc-Py-MoS_(2)exhibited a negligible decay of E_(1/2) after 50,000 CV cycles for ORR,showing its superior durability.This work gives us more insight into the influence of different hybrid strategies on Fe Pc catalysts and provides further guidance for the development of highly efficient and durable ORR catalysts.
基金supported by the National Key Research and Development Program of China(Nos.2019YFA0308500 and 2018YFA0305800)the National Natural Science Foundation of China(Nos.52022105 and 61888102)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDB28000000 and XDB30000000)。
文摘The control of the Kondo effect is of great interest in single-molecule junction due to its potential applications in spin based electronics.Here,we demonstrate that the Kondo effect is reversibly switched on and off in an iron phthalocyanine(FePc)single-molecule junction by using a superconducting Nb tip.In a scanning tunneling microscope-based Nb-insulator-FePc-Au junction,we achieve a reversible switching between the Kondo dip and inelastic electronic tunneling spectra by simply adjusting the tip-sample distance to tune the tunnel coupling at low temperature.Further approaching the tip leads to the picking up of the molecule to the tip apex,which transfers the geometry of the single-molecule junction into a Nb-FePc-insulator-Au type.As the molecule forms an effective magnetic impurity embedded into the superconducting ground states of the Nb tip,the out-gap Kondo dip switched to an in-gap Yu-Shiba-Rusinov state.Our results open up a new route for manipulating the Kondo effect within a single-molecule junction.
基金the Independent Cultivation Program of Innovation Team of Ji’nan City(No.2019GXRC011)the National Natural Science Foundation of China(Nos.21707043 and 51908242)the Natural Science Foundation of Shandong Province(No.ZR2017BEE005)。
文摘Improving the separation efficiency of photogenerated carriers and broadening the light absorption range of the photocatalyst are two important factors for improving the performance of the photocatalyst.In this paper,a new and efficient Z-scheme Cd S/iron phthalocyanine(Cd S/Fe Pc)core-shell nanostructure composite material is prepared by a simple solid-phase reaction method.There are two key points in the preparation of composite materials:one is that hydrogen bonding energy is closely connected with Fe Pc,another is that Fe Pc can be uniformly assembled on Cd S nanoparticles.The photocatalytic hydrogen evolution(PHE)of the Cd S/Fe Pc nanocomposite(73.01μmol/h)is 2.6 times higher than that of pure Cd S(26.67μmol/h).In addition,after 4 photocatalytic cycles,the PHE of the Cd S/Fe Pc composite is still 92.3%of the first cycle.There are three reasons for this situation:(1)The Z-scheme heterojunction is formed to improve the separation efficiency of photogenerated carriers;(2)Fe Pc expands the visible light absorption range of Cd S;(3)The large core-shell contact area is favorable for the separation of photo-induced carriers at the interfaces.This research is conducive to the further development of new photocatalytic materials with high efficiency,low cost and simple preparation.
