Aluminium is widely used as an antimicrobial coagulant,food additive,and cookware.However,many reports indicate that aluminium may be a critical factor in many amyloid diseases,such as Alzheimer’s disease and Parkin...Aluminium is widely used as an antimicrobial coagulant,food additive,and cookware.However,many reports indicate that aluminium may be a critical factor in many amyloid diseases,such as Alzheimer’s disease and Parkinson’s disease.Unfortunately,the underlying mechanism is still poorly understood,which limits efforts to prevent and treat these diseases.In this paper,using an ab initio method,we studied the interaction of Al-backbone ring structure with theπ-electron-rich sidechains of His,Phe,Trp,and Tyr.We found that in the absence of water,the Al-backbone ring can stably bind with those sidechains.In the presence of water,the Al-backbone ring can bind to the His sidechain and cannot bind to the other sidechains.As revealed by further investigations,this could be attributed to the fact that there was a coordinate bond of the Al-backbone ring with the His sidechain,while there were theπ-πstacking and cation-π-like interactions with the other sidechains.These findings potentially provide a molecular understanding of Al-related toxicity,and may be helpful in designing drugs for those aforementioned aluminum-linked diseases and encourage treatment of Al-polluted water.展开更多
The large 2219 Al alloy rings used to connect propellant tank components of a satellite launch vehicle to each other are conventionally manufactured by radial-axial ring rolling at 460°C with 50% deformation,but ...The large 2219 Al alloy rings used to connect propellant tank components of a satellite launch vehicle to each other are conventionally manufactured by radial-axial ring rolling at 460°C with 50% deformation,but often suffer from coarse elongated grain and low ductility. An improved process(hot ring rolling at460°C with 30% deformation, then air cooling to 240°C, followed by ring rolling at 240°C with 20% deformation) was tested for ring manufacturing. The corresponding microstructure evolution and mechanical properties of the produced rings were studied. The results show that the improved process can successfully be applied to manufacture the large 2219 Al alloy rings without formation of macroscopic defects,resulting in a product with fine and uniform grains after heat treatment. The fracture mechanism of both rings was mainly intergranular fracture. With the resulting grain size refinement due to the improved process, more homogeneous slip occured and the crack propagation path became more tortuous during the tensile testing process. Thus, the elongation in all three orthogonal directions was greatly improved,and the axial elongation increased from 3.5% to 10.0%.展开更多
基金Supported by National Natural Science Foundation of China(Nos.11174310 and 11290164)the Key Research Program of Chinese Academy of Sciences(No.KJZD-EW-M03)
文摘Aluminium is widely used as an antimicrobial coagulant,food additive,and cookware.However,many reports indicate that aluminium may be a critical factor in many amyloid diseases,such as Alzheimer’s disease and Parkinson’s disease.Unfortunately,the underlying mechanism is still poorly understood,which limits efforts to prevent and treat these diseases.In this paper,using an ab initio method,we studied the interaction of Al-backbone ring structure with theπ-electron-rich sidechains of His,Phe,Trp,and Tyr.We found that in the absence of water,the Al-backbone ring can stably bind with those sidechains.In the presence of water,the Al-backbone ring can bind to the His sidechain and cannot bind to the other sidechains.As revealed by further investigations,this could be attributed to the fact that there was a coordinate bond of the Al-backbone ring with the His sidechain,while there were theπ-πstacking and cation-π-like interactions with the other sidechains.These findings potentially provide a molecular understanding of Al-related toxicity,and may be helpful in designing drugs for those aforementioned aluminum-linked diseases and encourage treatment of Al-polluted water.
基金supported financially by the Joint Funds of the National Natural Science Foundation of China(No.U1637601)the Fund of Jiangsu Province for the Transformation of Scientific and Technological Achievements(No.BA2015075)the Project of Innovation-driven Plan for Postgraduate in Central South University(No.2016ZZTS048)
文摘The large 2219 Al alloy rings used to connect propellant tank components of a satellite launch vehicle to each other are conventionally manufactured by radial-axial ring rolling at 460°C with 50% deformation,but often suffer from coarse elongated grain and low ductility. An improved process(hot ring rolling at460°C with 30% deformation, then air cooling to 240°C, followed by ring rolling at 240°C with 20% deformation) was tested for ring manufacturing. The corresponding microstructure evolution and mechanical properties of the produced rings were studied. The results show that the improved process can successfully be applied to manufacture the large 2219 Al alloy rings without formation of macroscopic defects,resulting in a product with fine and uniform grains after heat treatment. The fracture mechanism of both rings was mainly intergranular fracture. With the resulting grain size refinement due to the improved process, more homogeneous slip occured and the crack propagation path became more tortuous during the tensile testing process. Thus, the elongation in all three orthogonal directions was greatly improved,and the axial elongation increased from 3.5% to 10.0%.
