Based on quasicontinuum（QC） multiscale simulation method,a series of simulation models were set up for bending and compressing rod-shaped microstructure of single crystal Cu.The effects of structural parameters on t...Based on quasicontinuum（QC） multiscale simulation method,a series of simulation models were set up for bending and compressing rod-shaped microstructure of single crystal Cu.The effects of structural parameters on typical mechanical properties were analyzed,such as elastic modulus,elastic limit,yield strength,and Poisson’s ratio.According to the analysis of displacement,inner stress and strain energy,the mechanisms of deformation and failure were also revealed.The experimental result shows that the mechanical properties exhibit obvious size effect during the bending and compression process.In the bending simulation,when the span-thickness ratio is more than 10,the elastic modulus rises slightly with the increase of strain.And the smaller the beam is,the faster the elastic modulus grows.Meanwhile,when the spanthickness ratio keeps constant the elastic modulus will decrease with the growth of the beam sizes.However,in the compression model,the size effect on Poisson’s ratio is not remarkable.The dimensional change in one direction cannot influence the mechanical parameters greatly.Mechanical twins and dislocation contribute to the compression behaviour greatly.Meanwhile,the stress concentration can also be found in the inner partial area and the strain energy decreases abruptly after the crush of beam microstructure.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Funded by the National Natural Science Foundation of China(No.51575138)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China(Grant Year 2013)
文摘Based on quasicontinuum（QC） multiscale simulation method,a series of simulation models were set up for bending and compressing rod-shaped microstructure of single crystal Cu.The effects of structural parameters on typical mechanical properties were analyzed,such as elastic modulus,elastic limit,yield strength,and Poisson’s ratio.According to the analysis of displacement,inner stress and strain energy,the mechanisms of deformation and failure were also revealed.The experimental result shows that the mechanical properties exhibit obvious size effect during the bending and compression process.In the bending simulation,when the span-thickness ratio is more than 10,the elastic modulus rises slightly with the increase of strain.And the smaller the beam is,the faster the elastic modulus grows.Meanwhile,when the spanthickness ratio keeps constant the elastic modulus will decrease with the growth of the beam sizes.However,in the compression model,the size effect on Poisson’s ratio is not remarkable.The dimensional change in one direction cannot influence the mechanical parameters greatly.Mechanical twins and dislocation contribute to the compression behaviour greatly.Meanwhile,the stress concentration can also be found in the inner partial area and the strain energy decreases abruptly after the crush of beam microstructure.
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.
