Detwinning is a unique deformation mechanism of nanotwinned metals with twin lamellae thickness down to a few nanometers.In this work we investigate the impact of detwinning mechanism on the tensile ductility of twinn...Detwinning is a unique deformation mechanism of nanotwinned metals with twin lamellae thickness down to a few nanometers.In this work we investigate the impact of detwinning mechanism on the tensile ductility of twinned Cu nanowires containing high density of parallel twin boundaries by means of molecular dynamics simulations.Simulation results show that the fracture strain of twinned Cu nanowires has a strong dependence on twin boundary spacing,resulting from the competition between individual deformation modes.Particularly for the twinned Cu nanowires containing the thinnest twin lamellaes,the dominant detwinning mechanism leads to a significant reduction in the tensile ductility.It is found that detwinning originates from twin boundary migration,which is a result of the glide of lattice partial dislocations on the twin planes.This work advances our fundamental understanding of the twin boundary-related mechanical properties of twinned metallic nanowires.展开更多
Better understanding of variations in the mechanical properties of cancer cells could help to provide novel solutions for the diagnosis,prevention,and treatment of cancers.We therefore developed a calculation model of...Better understanding of variations in the mechanical properties of cancer cells could help to provide novel solutions for the diagnosis,prevention,and treatment of cancers.We therefore developed a calculation model of the intracellular elastic modulus based on the contact pressure between the silicon tip of an atomic force microscope and the target cells,and cutting depth.Ovarian cells(UACC-1598) and colon cancer cells(NCI-H716) were cut into sequential layers using an atomic force microscope silicon tip.The cutting area on the cells was 8μm×8μm,and the loading force acting on the cells was increased from 17.523 to 32.126μN.The elastic modulus distribution was measured after each cutting process.There were significant differences in contact pressure and cutting depth between different cells under the same loading force,which could be attributed to differences in their intrinsic structures and mechanical properties.The differences between the average elastic modulus and surface elastic modulus for UACC-1598 and NCI-H716 cells were 0.288±0.08 kPa and 0.376±0.16 kPa,respectively.These results demonstrate that this micro-cutting method can be used to measure intracellular mechanical properties,which could in turn provide a more accurate experimental basis for the development of novel methods for the diagnosis and treatment of various diseases.展开更多
基金supported by China Postdoctoral Science Foundation(2012M511463)Heilongjiang Postdoctoral Foundation of China (LBH-Z11143)the ICAMS,Ruhr-University Bochum,Germany
文摘Detwinning is a unique deformation mechanism of nanotwinned metals with twin lamellae thickness down to a few nanometers.In this work we investigate the impact of detwinning mechanism on the tensile ductility of twinned Cu nanowires containing high density of parallel twin boundaries by means of molecular dynamics simulations.Simulation results show that the fracture strain of twinned Cu nanowires has a strong dependence on twin boundary spacing,resulting from the competition between individual deformation modes.Particularly for the twinned Cu nanowires containing the thinnest twin lamellaes,the dominant detwinning mechanism leads to a significant reduction in the tensile ductility.It is found that detwinning originates from twin boundary migration,which is a result of the glide of lattice partial dislocations on the twin planes.This work advances our fundamental understanding of the twin boundary-related mechanical properties of twinned metallic nanowires.
基金supported by the National Natural Science Foundation of China (51175124)the Self-Planned Task of State Key Laboratory of Robotics and System of Harbin Institute of Technology (SKLRS 200903C)
文摘Better understanding of variations in the mechanical properties of cancer cells could help to provide novel solutions for the diagnosis,prevention,and treatment of cancers.We therefore developed a calculation model of the intracellular elastic modulus based on the contact pressure between the silicon tip of an atomic force microscope and the target cells,and cutting depth.Ovarian cells(UACC-1598) and colon cancer cells(NCI-H716) were cut into sequential layers using an atomic force microscope silicon tip.The cutting area on the cells was 8μm×8μm,and the loading force acting on the cells was increased from 17.523 to 32.126μN.The elastic modulus distribution was measured after each cutting process.There were significant differences in contact pressure and cutting depth between different cells under the same loading force,which could be attributed to differences in their intrinsic structures and mechanical properties.The differences between the average elastic modulus and surface elastic modulus for UACC-1598 and NCI-H716 cells were 0.288±0.08 kPa and 0.376±0.16 kPa,respectively.These results demonstrate that this micro-cutting method can be used to measure intracellular mechanical properties,which could in turn provide a more accurate experimental basis for the development of novel methods for the diagnosis and treatment of various diseases.
