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
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.
