On purpose of studying the sluggish diffusion of high-entropy alloys, three different face centered cubic Co-Cr-Cu-Fe-Ni high-entropy alloys were prepared, and assembled into three groups of sandwich- type diffusion m...On purpose of studying the sluggish diffusion of high-entropy alloys, three different face centered cubic Co-Cr-Cu-Fe-Ni high-entropy alloys were prepared, and assembled into three groups of sandwich- type diffusion multiple annealed at 1273, 1323, and 1373 K respectively. By means of the electron probe microanalyzer technique and recently developed numerical inverse method, the composition- dependent interdiffusivities at different temperatures were effectively evaluated by minimizing the residual between the model-predicted compositions/interdiffusion fluxes and the respectively experi- mental ones. After that, the tracer diffusivities were predicted based on the assessed mobility parameters and thermodynamic descriptions with the simplified ideal solution model. The comprehensive compari- son between the interdiffusivities/tracer diffusivities in the Co-Cr-Cu-Fe-Ni high-entropy alloys and those in sub-binary, ternary, quaternary and other quinary alloys indicates that the sluggish diffusion exists in interdiffusion instead of tracer diffusion for the present Co-Cr-Cu-Fe-Ni high-entropy alloys.展开更多
SMEI(small and medium-sized company confidence index)released by Standard Charted Bank in June shows that the operation of SMEs keeps sluggish momentum for the second month consecutively.SEMI dropped to 55.2 from 56.0...SMEI(small and medium-sized company confidence index)released by Standard Charted Bank in June shows that the operation of SMEs keeps sluggish momentum for the second month consecutively.SEMI dropped to 55.2 from 56.0 last month,although there is a slight increase of average value from 55.1 to 56.6 for Q2.The enterprise展开更多
Throughout 2018, the global economy maintained a state of recovery on the whole, yet its foundation for growth is far from solid, the speed of growth is decelerating, and growth drivers are beginning to weaken. The ec...Throughout 2018, the global economy maintained a state of recovery on the whole, yet its foundation for growth is far from solid, the speed of growth is decelerating, and growth drivers are beginning to weaken. The economy faces visibly more factors of uncertainty and instability, the deep-rooted affects of the global financial crisis continue to reverberate, and various structural issues remain prominent;moving forward, the road to recovery will not be a smooth one.展开更多
Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,th...Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.展开更多
The world economy in 2024 proved surprisingly resilient despite multiple shocks. This resilience can largely be attributed to the effects of tight monetary policies and the strong performance of labor markets in major...The world economy in 2024 proved surprisingly resilient despite multiple shocks. This resilience can largely be attributed to the effects of tight monetary policies and the strong performance of labor markets in major economies. Although a recession was narrowly avoided, the intensifying strategic rivalries among major powers, rising geopolitical risks, the resurgence of trade protectionism and sluggish global growth have all cast a shadow over the economic outlook.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.51474239)the National Key Research and Development Program of China(Grant No.2016YFB0301101)+1 种基金financial support from the Huxiang Youth Talent Plan released by Hunan Province,Chinathe project supported by State Key Laboratory of Powder Metallurgy Foundation,Central South University,Changsha,China
文摘On purpose of studying the sluggish diffusion of high-entropy alloys, three different face centered cubic Co-Cr-Cu-Fe-Ni high-entropy alloys were prepared, and assembled into three groups of sandwich- type diffusion multiple annealed at 1273, 1323, and 1373 K respectively. By means of the electron probe microanalyzer technique and recently developed numerical inverse method, the composition- dependent interdiffusivities at different temperatures were effectively evaluated by minimizing the residual between the model-predicted compositions/interdiffusion fluxes and the respectively experi- mental ones. After that, the tracer diffusivities were predicted based on the assessed mobility parameters and thermodynamic descriptions with the simplified ideal solution model. The comprehensive compari- son between the interdiffusivities/tracer diffusivities in the Co-Cr-Cu-Fe-Ni high-entropy alloys and those in sub-binary, ternary, quaternary and other quinary alloys indicates that the sluggish diffusion exists in interdiffusion instead of tracer diffusion for the present Co-Cr-Cu-Fe-Ni high-entropy alloys.
文摘SMEI(small and medium-sized company confidence index)released by Standard Charted Bank in June shows that the operation of SMEs keeps sluggish momentum for the second month consecutively.SEMI dropped to 55.2 from 56.0 last month,although there is a slight increase of average value from 55.1 to 56.6 for Q2.The enterprise
文摘Throughout 2018, the global economy maintained a state of recovery on the whole, yet its foundation for growth is far from solid, the speed of growth is decelerating, and growth drivers are beginning to weaken. The economy faces visibly more factors of uncertainty and instability, the deep-rooted affects of the global financial crisis continue to reverberate, and various structural issues remain prominent;moving forward, the road to recovery will not be a smooth one.
基金support of the National Natural Science Foundation of China(Grant No.22225801,22178217 and 22308216)supported by the Fundamental Research Funds for the Central Universities,conducted at Tongji University.
文摘Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.
文摘The world economy in 2024 proved surprisingly resilient despite multiple shocks. This resilience can largely be attributed to the effects of tight monetary policies and the strong performance of labor markets in major economies. Although a recession was narrowly avoided, the intensifying strategic rivalries among major powers, rising geopolitical risks, the resurgence of trade protectionism and sluggish global growth have all cast a shadow over the economic outlook.
