Although room temperature ionic liquids(ILs)have emerged as potential next-generation electrolytes for their wide electrochemical stability window(ESW),the trade-off between this window and viscosity has hindered thei...Although room temperature ionic liquids(ILs)have emerged as potential next-generation electrolytes for their wide electrochemical stability window(ESW),the trade-off between this window and viscosity has hindered their widespread use in energy storage devices.Here,we present for the first time that such a trade-off can be balanced by mixing two ILs with the common anion([NTf_(2)]^(-))but different cations([EMIM]^(+) and[N1114]^(+))together.The[EMIM]cation-based IL possesses low viscosity while the[N1114]cation-based IL exhibits wide ESW.Since the concentrations of each IL in the mixtures can result in different electrolyte properties,we demonstrate a systematic approach by exploring the properties of various concentration combinations.In addition,the corresponding cell voltage of their resulting graphene supercapacitors(SCs)accompanied based on the interaction between the binary ionic liquid and the electrodes,and the associated electrochemical performance were studied to determine the optimum electrolyte system for the highest SC energy density.The well-balanced viscosity/ESW trade-off is achieved in binary IL consisting 50 vol%[EMIM][NTf_(2)]and 50 vol%[N1114][NTf_(2)]as evident from the extraordinary electrode specific capacitance of 293.1 F g^(-1) and the ultrahigh SC energy density of 177 Wh kg^(-1),which approaches that of a lithium-ion battery.展开更多
An irreversible light-driven engine is described in this paper,in which the heat transfer between the working fluid and the environment obeys a linear phenomenological heat transfer law[q∝Δ(T-1)],with a working flui...An irreversible light-driven engine is described in this paper,in which the heat transfer between the working fluid and the environment obeys a linear phenomenological heat transfer law[q∝Δ(T-1)],with a working fluid composed of the bimolecular reacting system 2SO 3 F■S 2 O 6 F2.Piston trajectories maximizing work output and minimizing entropy generation are determined for such an engine with rate-dependent loss mechanisms of friction and heat leakage.The optimal control theory is applied to determine the optimal configurations of the piston motion trajectory and the fluid temperature.Numerical examples for the optimal configuration are provided,and the obtained results are compared with those derived with Newtonian heat transfer law[q∝Δ(T)].展开更多
The maximum work principle of Bishop-Hill was developed to analyze the axisymmetric co-deformation in face-centered cubic crystals(f.c.c.)for twinning on{111}112 and slip on{111}110 systems.The influence ofξ,the rati...The maximum work principle of Bishop-Hill was developed to analyze the axisymmetric co-deformation in face-centered cubic crystals(f.c.c.)for twinning on{111}112 and slip on{111}110 systems.The influence ofξ,the ratio of critical re-solved shear stress for twinning to slip,on the yield stress states and corresponding active slip or/and twinning systems for orientations in the standard stereographic triangle of cubic crystal was investigated systematically.The Taylor factors and the anisotropy of yield strength for three important orientations[100],[110]and[111]in orientation space were analyzed.It is found that the yield strength asymmetry for the case of axisymmetric de-formation of tension and compression can be explained based on the microscopic theory of crystal plasticity.The concept of orientation factor for twinning ability was proposed and the deformation mechanism map in the orientation space was established for the case of axisymmetric deformation.The deformation texture formation and development of f.c.c.crystals with low stacking fault energy for axisymmetric tension can be explained qualita-tively on the basis of analyzed results.展开更多
基金Baohua Jia and Han Lin acknowledges the Australia Research Council through the Discovery Project Scheme(DP190103186,DP220100603,FT210100806)the Industrial Transformation Training Centre Scheme(Grant No.IC180100005)The authors wish to express gratitude to the Swinburne Melbourne and Swinburne Sarawak for funding this project under the‘Melbourne-Sarawak Research Collaboration Scheme’(MSRSC)grant.
文摘Although room temperature ionic liquids(ILs)have emerged as potential next-generation electrolytes for their wide electrochemical stability window(ESW),the trade-off between this window and viscosity has hindered their widespread use in energy storage devices.Here,we present for the first time that such a trade-off can be balanced by mixing two ILs with the common anion([NTf_(2)]^(-))but different cations([EMIM]^(+) and[N1114]^(+))together.The[EMIM]cation-based IL possesses low viscosity while the[N1114]cation-based IL exhibits wide ESW.Since the concentrations of each IL in the mixtures can result in different electrolyte properties,we demonstrate a systematic approach by exploring the properties of various concentration combinations.In addition,the corresponding cell voltage of their resulting graphene supercapacitors(SCs)accompanied based on the interaction between the binary ionic liquid and the electrodes,and the associated electrochemical performance were studied to determine the optimum electrolyte system for the highest SC energy density.The well-balanced viscosity/ESW trade-off is achieved in binary IL consisting 50 vol%[EMIM][NTf_(2)]and 50 vol%[N1114][NTf_(2)]as evident from the extraordinary electrode specific capacitance of 293.1 F g^(-1) and the ultrahigh SC energy density of 177 Wh kg^(-1),which approaches that of a lithium-ion battery.
基金supported by the Program for New Century Excellent Tal-ents in University of China(Grant No.20041006)the Foundation for the Authors of National Excellent Doctoral Dissertation of China(Grant No.200136)
文摘An irreversible light-driven engine is described in this paper,in which the heat transfer between the working fluid and the environment obeys a linear phenomenological heat transfer law[q∝Δ(T-1)],with a working fluid composed of the bimolecular reacting system 2SO 3 F■S 2 O 6 F2.Piston trajectories maximizing work output and minimizing entropy generation are determined for such an engine with rate-dependent loss mechanisms of friction and heat leakage.The optimal control theory is applied to determine the optimal configurations of the piston motion trajectory and the fluid temperature.Numerical examples for the optimal configuration are provided,and the obtained results are compared with those derived with Newtonian heat transfer law[q∝Δ(T)].
基金supported by the National Natural Science Foundation of China(Grant Nos.50301016 and 59971067)the China Postdoctoral Science Foundation(Grant No.2005037003).
文摘The maximum work principle of Bishop-Hill was developed to analyze the axisymmetric co-deformation in face-centered cubic crystals(f.c.c.)for twinning on{111}112 and slip on{111}110 systems.The influence ofξ,the ratio of critical re-solved shear stress for twinning to slip,on the yield stress states and corresponding active slip or/and twinning systems for orientations in the standard stereographic triangle of cubic crystal was investigated systematically.The Taylor factors and the anisotropy of yield strength for three important orientations[100],[110]and[111]in orientation space were analyzed.It is found that the yield strength asymmetry for the case of axisymmetric de-formation of tension and compression can be explained based on the microscopic theory of crystal plasticity.The concept of orientation factor for twinning ability was proposed and the deformation mechanism map in the orientation space was established for the case of axisymmetric deformation.The deformation texture formation and development of f.c.c.crystals with low stacking fault energy for axisymmetric tension can be explained qualita-tively on the basis of analyzed results.
