As a popular anode material for lithium-ion batteries,anatase TiO2 nanoparticles with exposed{001}facets usually exhibit exceptional lithium storage performance owing to more accessible sites and fast migration of lit...As a popular anode material for lithium-ion batteries,anatase TiO2 nanoparticles with exposed{001}facets usually exhibit exceptional lithium storage performance owing to more accessible sites and fast migration of lithium ions along the good crystalline channels.However,there are few researches on the lithium storage capability of TiO2 nanocrystals with other high-energy facets owing to lack of effective synthesis method for controlling crystal facets.Herein,anatase TiO2 nanocrystals with exposed{010}-and[111]-facets are successfully prepared by using the delaminated tetratitanate nanoribbons as precursors.The electrochemical properties of these TiO2 nanocrystals with high-energy surfaces and the comparison with commercial TiO2 nanoparticles(P25)are studied.It is found that the cycle and rate performance of TiO2 nanocrystals is highly improved by reducing the particle size of nanocrystals.Moreover,TiO2 nanocrystals with exposed{010}-and[111]-facets exhibit better lithium storage capacities in comparison with P25 without a specific facet though P25 has smaller particle size than these TiO2 nanocrystals,indicating that the exposed facets of TiO2 nanocrystals have an important impact on their lithium storage capacity.Therefore,the synthesis design of high-performance TiO2 materials applied in the next-generation secondary batteries should both consider the particle size and the exposed facets of nanocrystals.展开更多
Assisted by framework of multimedia total exposure model for hazard waste sites(CalTOX),potential influences of scenario-uncertainty on multimedia health risk assessment(MHRA) and decision-making were quantitatively a...Assisted by framework of multimedia total exposure model for hazard waste sites(CalTOX),potential influences of scenario-uncertainty on multimedia health risk assessment(MHRA) and decision-making were quantitatively analyzed in a primary extent under the Chinese scenario case by deliberately varying the two key scenario-elements,namely conceptual exposure pathways combination and aim receptor cohorts choice.Results show that the independent change of one exposure pathway or receptor cohort could lead variation of MHRA results in the range of 3.6×10-6-1.4×10-5 or 6.7×10-6-2.3×10-5.And randomly simultaneous change of those two elements could lead variation of MHRA results at the range of 7.7×10-8-2.3×10-5.On the basis of the corresponding sensitivity analysis,pathways which made a valid contribution to the final modeling risk value occupied only 16.7% of all considered pathways.Afterwards,comparative analysis between influence of parameter-uncertainty and influence of scenario-uncertainty was made.In consideration of interrelationship among all types of uncertainties and financial reasonability during MHRA procedures,the integrated method how to optimize the entire procedures of MHRA was presented innovatively based on sensitivity analysis,scenario-discussion and nest Monte Carlo simulation or fuzzy mathematics.展开更多
In the present work,samples of Al-Si-Cu piston alloy after T6 heat treatment were exposed for 2 h at temperatures ranging from 400 to 550°C.The evolution of surface roughness and microstructure of the alloy durin...In the present work,samples of Al-Si-Cu piston alloy after T6 heat treatment were exposed for 2 h at temperatures ranging from 400 to 550°C.The evolution of surface roughness and microstructure of the alloy during thermal exposure was studied by combination methods of roughness profiles,optical and scanning electron microscopy as well as XRD analysis.It is found that the roughness and mass of the alloy increase with the raise of the thermal exposure temperature,and the increasing rates of them are slow as the exposure temperature is below 500°C,but accelerates abruptly when the temperature is higher than 500°C.The variation of surface roughness of the alloy is closely related to phase transformation and oxidation during the thermal exposure.展开更多
基金Projects(21573023,51572031)supported by the National Natural Science Foundation of ChinaProject supported by the Grants-in-Acid for Doctor Research Funds+1 种基金Project supported by “1331 Project” for Innovation Team Construction Plan Funds of Jinzhong University,ChinaProject supported by “1331 Project” for 2018 Key Innovation Team Construction Plan Funds of Shanxi Province,China
文摘As a popular anode material for lithium-ion batteries,anatase TiO2 nanoparticles with exposed{001}facets usually exhibit exceptional lithium storage performance owing to more accessible sites and fast migration of lithium ions along the good crystalline channels.However,there are few researches on the lithium storage capability of TiO2 nanocrystals with other high-energy facets owing to lack of effective synthesis method for controlling crystal facets.Herein,anatase TiO2 nanocrystals with exposed{010}-and[111]-facets are successfully prepared by using the delaminated tetratitanate nanoribbons as precursors.The electrochemical properties of these TiO2 nanocrystals with high-energy surfaces and the comparison with commercial TiO2 nanoparticles(P25)are studied.It is found that the cycle and rate performance of TiO2 nanocrystals is highly improved by reducing the particle size of nanocrystals.Moreover,TiO2 nanocrystals with exposed{010}-and[111]-facets exhibit better lithium storage capacities in comparison with P25 without a specific facet though P25 has smaller particle size than these TiO2 nanocrystals,indicating that the exposed facets of TiO2 nanocrystals have an important impact on their lithium storage capacity.Therefore,the synthesis design of high-performance TiO2 materials applied in the next-generation secondary batteries should both consider the particle size and the exposed facets of nanocrystals.
基金Projects(50978088,51039001,51178172,51009063) supported by the National Natural Science Foundation of ChinaProject(NCET-08- 180) supported by the Program for New Century Excellent Talents in University from the Ministry of Education of China
文摘Assisted by framework of multimedia total exposure model for hazard waste sites(CalTOX),potential influences of scenario-uncertainty on multimedia health risk assessment(MHRA) and decision-making were quantitatively analyzed in a primary extent under the Chinese scenario case by deliberately varying the two key scenario-elements,namely conceptual exposure pathways combination and aim receptor cohorts choice.Results show that the independent change of one exposure pathway or receptor cohort could lead variation of MHRA results in the range of 3.6×10-6-1.4×10-5 or 6.7×10-6-2.3×10-5.And randomly simultaneous change of those two elements could lead variation of MHRA results at the range of 7.7×10-8-2.3×10-5.On the basis of the corresponding sensitivity analysis,pathways which made a valid contribution to the final modeling risk value occupied only 16.7% of all considered pathways.Afterwards,comparative analysis between influence of parameter-uncertainty and influence of scenario-uncertainty was made.In consideration of interrelationship among all types of uncertainties and financial reasonability during MHRA procedures,the integrated method how to optimize the entire procedures of MHRA was presented innovatively based on sensitivity analysis,scenario-discussion and nest Monte Carlo simulation or fuzzy mathematics.
基金Project(DLBF2018-KY-JS-066-J)supported by China North Engine Research InstituteProject(XAGDXJJ17008)supported by the Principal Fund of Xi’an Technological University,ChinaProjects(19JK0400,19JK0402)supported by the Education Fund of Shaanxi Province,China。
文摘In the present work,samples of Al-Si-Cu piston alloy after T6 heat treatment were exposed for 2 h at temperatures ranging from 400 to 550°C.The evolution of surface roughness and microstructure of the alloy during thermal exposure was studied by combination methods of roughness profiles,optical and scanning electron microscopy as well as XRD analysis.It is found that the roughness and mass of the alloy increase with the raise of the thermal exposure temperature,and the increasing rates of them are slow as the exposure temperature is below 500°C,but accelerates abruptly when the temperature is higher than 500°C.The variation of surface roughness of the alloy is closely related to phase transformation and oxidation during the thermal exposure.
