On the basis of the two geological factors rock structure and ground stress environment,a visco elastic plastic model is established to analyze the rock stability of dam foundation and dam abutment during excavation...On the basis of the two geological factors rock structure and ground stress environment,a visco elastic plastic model is established to analyze the rock stability of dam foundation and dam abutment during excavation by a kind of FE condensed method.Rock mechanics is applied in analysing the dynamic process of displacements,stresses,yielding destruction of construction base level,soft interface of dam foundation.Results of the FE analysis indicate that theories and methods in this paper are reasonable and reliable.展开更多
Lithium metal batteries are regarded as promising alternatives to lithium ion batteries due to their high specific capacity.However,lithium dendrite growth during cycling causes safety problem and rapid capacity loss....Lithium metal batteries are regarded as promising alternatives to lithium ion batteries due to their high specific capacity.However,lithium dendrite growth during cycling causes safety problem and rapid capacity loss.Here,we report a composite Li anode composed(LYF)of metallic Li and trace amounts(1 e2 wt%)of two-dimensional YF_(δ).The lithiophilic nature of YF_(δ) enables its homogeneous dispersion in metallic lithium.The LYF electrode exhibits lower resistance,higher chemical and mechanical stability,and longer cycle life compared to bare Li electrode due to uniform Li stripping and plating with YF_(δ) incorporation,which was confirmed by in-situ optical microscope observation.X-ray photoelectron spectroscopy reveals that LiF can in-situ form on the LYF electrode with reactions between Li and YF_(δ) during cycling.The spontaneous reactions are clarified by density functional theory calculations.A quasisolid-state cell with LYF anode,LiFePO_(4) cathode and cathode-supported solid electrolyte layer has been constructed with a soft interface constructed between Li anode and solid electrolyte by in-situ thermal polymerization.The cell shows a high initial discharge capacity of 147 mAh g1 at 0.5℃ at 60℃ and sustains a stable cycling over 50 cycles with the in-situ formed LiF-rich layer and soft interface.展开更多
The deformation and micro-voids formation mechanisms in ferrite / bainite（ F / B） multi-phase steel with the volume fraction of bainite less than 50% were studied by numerical simulation and experimental observation...The deformation and micro-voids formation mechanisms in ferrite / bainite（ F / B） multi-phase steel with the volume fraction of bainite less than 50% were studied by numerical simulation and experimental observation. The results show that the micro-strain concentrates at the soft / hard phase（ F / B） interface in the multi-phase steel,which should be correlated with the mechanism of incoordinate deformation. During the necking of the steel,the micro-voids initially form around the F / B interface,which also form in ferrite and bainite with the severe strain. The micro-voids in bainite are more dense and finer than those in ferrite. The failure mechanism of bainite is the coalescence of micro-voids,and the failure mechanism of ferrite is the growth and tearing of micro-voids. Due to the different failure mechanisms of ferrite and bainite,a suitable part of soft phase would be beneficial to the capability of anti-failure of F / B multi-phase steel during the ductile fracture.展开更多
文摘On the basis of the two geological factors rock structure and ground stress environment,a visco elastic plastic model is established to analyze the rock stability of dam foundation and dam abutment during excavation by a kind of FE condensed method.Rock mechanics is applied in analysing the dynamic process of displacements,stresses,yielding destruction of construction base level,soft interface of dam foundation.Results of the FE analysis indicate that theories and methods in this paper are reasonable and reliable.
基金supported by the National Natural Science Foundation of China(Grant no.51572238,51725102)and Zhejiang Provincial Natural Science Foundation of China(Grant no.LY19E020013).
文摘Lithium metal batteries are regarded as promising alternatives to lithium ion batteries due to their high specific capacity.However,lithium dendrite growth during cycling causes safety problem and rapid capacity loss.Here,we report a composite Li anode composed(LYF)of metallic Li and trace amounts(1 e2 wt%)of two-dimensional YF_(δ).The lithiophilic nature of YF_(δ) enables its homogeneous dispersion in metallic lithium.The LYF electrode exhibits lower resistance,higher chemical and mechanical stability,and longer cycle life compared to bare Li electrode due to uniform Li stripping and plating with YF_(δ) incorporation,which was confirmed by in-situ optical microscope observation.X-ray photoelectron spectroscopy reveals that LiF can in-situ form on the LYF electrode with reactions between Li and YF_(δ) during cycling.The spontaneous reactions are clarified by density functional theory calculations.A quasisolid-state cell with LYF anode,LiFePO_(4) cathode and cathode-supported solid electrolyte layer has been constructed with a soft interface constructed between Li anode and solid electrolyte by in-situ thermal polymerization.The cell shows a high initial discharge capacity of 147 mAh g1 at 0.5℃ at 60℃ and sustains a stable cycling over 50 cycles with the in-situ formed LiF-rich layer and soft interface.
基金Item Sponsored by National Basic Research Program of China(2010CB630801)
文摘The deformation and micro-voids formation mechanisms in ferrite / bainite（ F / B） multi-phase steel with the volume fraction of bainite less than 50% were studied by numerical simulation and experimental observation. The results show that the micro-strain concentrates at the soft / hard phase（ F / B） interface in the multi-phase steel,which should be correlated with the mechanism of incoordinate deformation. During the necking of the steel,the micro-voids initially form around the F / B interface,which also form in ferrite and bainite with the severe strain. The micro-voids in bainite are more dense and finer than those in ferrite. The failure mechanism of bainite is the coalescence of micro-voids,and the failure mechanism of ferrite is the growth and tearing of micro-voids. Due to the different failure mechanisms of ferrite and bainite,a suitable part of soft phase would be beneficial to the capability of anti-failure of F / B multi-phase steel during the ductile fracture.
