Lithium-sulfur(Li-S)battery has attracted intensive attention in the realm of energy storage owing to its high theoretical capacity and energy density.However,the shuttle effect of soluble lithium polysulfides(LiPSs)b...Lithium-sulfur(Li-S)battery has attracted intensive attention in the realm of energy storage owing to its high theoretical capacity and energy density.However,the shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes results in rapid capacity degradation.Herein,a strategy which combines the design of both chemical interaction and microstructure of interlayer was proposed to suppress the shuttle effect.The chemical interaction between different functionalized MOFs and LiPSs was systematically studied to find the best candidate.Furthermore,an interlayer with ordered structure was constructed via the layer-by-layer assembly of metal-organic frameworks(MOFs)on graphene(UiO-66-NH_(2)@graphene)to create sinuous channels which can better impede the diffusion process of LiPSs by the strong adsorption of MOF toward LiPSs.Consequently,in comparison to the battery with a bare separator,the ordered interlayer increased the initial discharge capacity of battery by 28.98%at 1.0 C and lowered the capacity decay rate remarkably from 0.10%to 0.067%per cycle,indicating that the design of chemical interaction and microstructure paves the way for high-performance Li-S batteries.展开更多
Mineral resources are the most important natural resources for developing countries. Bauxite is an indispensable mineral resource for industrial production. Potential assessment of bauxite is an important issue in Ind...Mineral resources are the most important natural resources for developing countries. Bauxite is an indispensable mineral resource for industrial production. Potential assessment of bauxite is an important issue in Indochina Peninsula. In this paper, the factors affecting the mineralization of the lateritic bauxite are analyzed. The collected spatial data are processed and the information is extracted to obtain the spatial extent of favorable constraints. Then, the spatial distribution of potential bauxites on the Bolaven Plateau has been investigated with a Boolean modeling process in GIS environment on the basis of some constraints such as rock, elevation, topographical features and vegetation coverage. Finally, based on the hydrogeological conditions and alteration information of Fe3+ and OH-, the bauxite mapping has been carried out. There are twenty bauxite metallogenic areas delineated, with a total area of 750 km2, which is 5% of the entire study area. This has greatly reduced the scope of the field investigation. Seven of the twenty predicted areas were validated in the field and six of them were found to have bauxite mineralization. Using the methods proposed in this study, the potential bauxite for the entire Bolaven Plateau could be achieved much more cheaply than the traditional methods. This study also provides a good idea for the prediction of laterite bauxite in the other regions of the Indochina Peninsula.展开更多
In this paper,we discuss an algebraic multigrid(AMG)method for nearly incompressible elasticity problems in two-dimensions.First,a two-level method is proposed by analyzing the relationship between the linear finite e...In this paper,we discuss an algebraic multigrid(AMG)method for nearly incompressible elasticity problems in two-dimensions.First,a two-level method is proposed by analyzing the relationship between the linear finite element space and the quartic finite element space.By choosing different smoothers,we obtain two types of two-level methods,namely TL-GS and TL-BGS.The theoretical analysis and numerical results show that the convergence rates of TL-GS and TL-BGS are independent of the mesh size and the Young’s modulus,and the convergence of the latter is greatly improved on the order p.However the convergence of both methods still depends on the Poisson’s ratio.To fix this,we obtain a coarse level matrix with less rigidity based on selective reduced integration(SRI)method and get some types of two-level methods by combining different smoothers.With the existing AMG method used as a solver on the first coarse level,an AMG method can be finally obtained.Numerical results show that the resulting AMG method has better efficiency for nearly incompressible elasticity problems.展开更多
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(Nos.51920105004 and 51902060)the Foundation for Young Talents in Higher Education of Guangdong,China(No.2018KQNCX065)National Natural Science Foundation of Guangdong,China(No.2019A1515010842).
文摘Lithium-sulfur(Li-S)battery has attracted intensive attention in the realm of energy storage owing to its high theoretical capacity and energy density.However,the shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes results in rapid capacity degradation.Herein,a strategy which combines the design of both chemical interaction and microstructure of interlayer was proposed to suppress the shuttle effect.The chemical interaction between different functionalized MOFs and LiPSs was systematically studied to find the best candidate.Furthermore,an interlayer with ordered structure was constructed via the layer-by-layer assembly of metal-organic frameworks(MOFs)on graphene(UiO-66-NH_(2)@graphene)to create sinuous channels which can better impede the diffusion process of LiPSs by the strong adsorption of MOF toward LiPSs.Consequently,in comparison to the battery with a bare separator,the ordered interlayer increased the initial discharge capacity of battery by 28.98%at 1.0 C and lowered the capacity decay rate remarkably from 0.10%to 0.067%per cycle,indicating that the design of chemical interaction and microstructure paves the way for high-performance Li-S batteries.
基金supported by the China Geological Survey(No.121201010000150013)the National Natural Science Foundation of China(No.41102225)
文摘Mineral resources are the most important natural resources for developing countries. Bauxite is an indispensable mineral resource for industrial production. Potential assessment of bauxite is an important issue in Indochina Peninsula. In this paper, the factors affecting the mineralization of the lateritic bauxite are analyzed. The collected spatial data are processed and the information is extracted to obtain the spatial extent of favorable constraints. Then, the spatial distribution of potential bauxites on the Bolaven Plateau has been investigated with a Boolean modeling process in GIS environment on the basis of some constraints such as rock, elevation, topographical features and vegetation coverage. Finally, based on the hydrogeological conditions and alteration information of Fe3+ and OH-, the bauxite mapping has been carried out. There are twenty bauxite metallogenic areas delineated, with a total area of 750 km2, which is 5% of the entire study area. This has greatly reduced the scope of the field investigation. Seven of the twenty predicted areas were validated in the field and six of them were found to have bauxite mineralization. Using the methods proposed in this study, the potential bauxite for the entire Bolaven Plateau could be achieved much more cheaply than the traditional methods. This study also provides a good idea for the prediction of laterite bauxite in the other regions of the Indochina Peninsula.
基金supported in part by NSF-10771178 and NSF-10672138 in Chinathe Basic Research Program of China under the grant 2005CB321702+1 种基金the Key Project of Chinese Ministry of Education and the Scientific Research Fund of Hunan Provincial Education Department(208093,07A068)the Provincial Natural Science Foundation of Hunan(07JJ6004)。
文摘In this paper,we discuss an algebraic multigrid(AMG)method for nearly incompressible elasticity problems in two-dimensions.First,a two-level method is proposed by analyzing the relationship between the linear finite element space and the quartic finite element space.By choosing different smoothers,we obtain two types of two-level methods,namely TL-GS and TL-BGS.The theoretical analysis and numerical results show that the convergence rates of TL-GS and TL-BGS are independent of the mesh size and the Young’s modulus,and the convergence of the latter is greatly improved on the order p.However the convergence of both methods still depends on the Poisson’s ratio.To fix this,we obtain a coarse level matrix with less rigidity based on selective reduced integration(SRI)method and get some types of two-level methods by combining different smoothers.With the existing AMG method used as a solver on the first coarse level,an AMG method can be finally obtained.Numerical results show that the resulting AMG method has better efficiency for nearly incompressible elasticity problems.
