Spinal cord injuries(SCI)usually result in impairment of axonal conduction and sensorimotor function.There are no effective therapy to completely repair SCI.Axonal demyelination is very common as a pathologic change i...Spinal cord injuries(SCI)usually result in impairment of axonal conduction and sensorimotor function.There are no effective therapy to completely repair SCI.Axonal demyelination is very common as a pathologic change in SCI,and demyelination partly contributes to neural function impairment.So,it may be reasonable that remyelination of demyelinated axons become one of effective therapeutic targets for SCI treatment. Demyelination involves myelin breakdown and loss of myelin-forming cells(oligodendrocytes).The death of oligodendrocytes plays a key role in axonal demyelination in SCI.Recently a number of studies demonstrate that cell replacements could facilitate axonal remyelination and restore axonal conductive func- tion.Thus,it is expected that myelinogenetic cell transplantation(oligodendroglial lineage)will have good prospect as an effective therapy to improve axonal remyelination and restore neural function for SCI treat- ment in the near future.展开更多
The friction coefficient between tube and die in guide zone of tube hydroforming was obtained. In hydroforming, the tube is expanded by an internal pressure against the tool wall. By pushing the tube through tool, a f...The friction coefficient between tube and die in guide zone of tube hydroforming was obtained. In hydroforming, the tube is expanded by an internal pressure against the tool wall. By pushing the tube through tool, a friction force at the contact surface between the tube and the tool occurs. In guiding zone, the friction coefficients between tube and die can be estimated from the measured axial feeding forces. In expansion zone, the friction coefficients between tube and die can be evaluated from the measured geometries of expanded tubes and FE analysis.展开更多
In this paper,an elasto-viscoplastic three-dimension(3D) finite element model is developed to simulate the processing of bimetal tube with rotary swaging. Through simulation,the effects of high-frequency pulse strokin...In this paper,an elasto-viscoplastic three-dimension(3D) finite element model is developed to simulate the processing of bimetal tube with rotary swaging. Through simulation,the effects of high-frequency pulse stroking on the distribution and histories of stress,stain and loading are clarified. The stress in inner tube is compressive and higher than the minimum bonding force. Meanwhile,the stiffness of inner tube impacts outer tube extension in length.展开更多
Some materials form better than others, moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another Configuration. The forming limit of a metal sheet is generall...Some materials form better than others, moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another Configuration. The forming limit of a metal sheet is generally given in terms of the limiting principal strains under different loading conditions and represented by the so-called FLD （forming limit diagram）. In view of the difficulty to experimentally determine the forming limits, many researchers have sought to predict FLD. The formability of sheet metal has frequently been expressed by the value of strain hardening exponent and plastic anisotropy ratio. The stress-strain and hardening behaviour of a material is very important in determining its resistance to plastic instability. For these reasons, extensive test programs are often carried out in an attempt to correlate material formability with value of some mechanical properties. In this study, mechanical properties and the FLD of the AMS 5596 sheet metal was determined by using uniaxial tensile test and Marciniak＇s flat bottomed punch test respectively.展开更多
By using Total Routhian Surface （TRS） method the deformation of the nucleus ^160Yb is studied. The result shows that the triaxial superdeformed state exists with deformation parameters ε2 = 0.38 and γ = 21°, ...By using Total Routhian Surface （TRS） method the deformation of the nucleus ^160Yb is studied. The result shows that the triaxial superdeformed state exists with deformation parameters ε2 = 0.38 and γ = 21°, where proton shell correction energy plays a key role, and the sum of two quasi-proton particle energies gives an additional driving effect. The rotational energy also has an additional role in the formation of triaxial superdeformed.展开更多
Since Caenorhabditis elegans was chosen as a model organism by Sydney Brenner in 1960's, genetic studies in this organism have been instrumental in discovering the function of genes and in deciphering molecular si...Since Caenorhabditis elegans was chosen as a model organism by Sydney Brenner in 1960's, genetic studies in this organism have been instrumental in discovering the function of genes and in deciphering molecular signaling network. The small size of the organism and the simple nervous system enable the complete reconstruction of the first connectome. The stereotypic developmental program and the anatomical reproducibility of synaptic connections provide a blueprint to dissect the mechanisms underlying synapse formation. Recent technological innovation using laser surgery of single axons and in vivo imaging has also made C. elegans a new model for axon regeneration. Importantly, genes regulating synaptogenesis and axon regeneration are highly conserved in function across animal phyla. This mini-review will summarize the main approaches and the key findings in understanding the mechanisms underlying the development and maintenance of the nervous system. The impact of such findings underscores the awesome power of C. elegans genetics.展开更多
Numerous experimental and theoretical studies on recycled aggregate concrete have been carried out in China in the past 10 years.This paper provides a comprehensive review of the related findings of research on the me...Numerous experimental and theoretical studies on recycled aggregate concrete have been carried out in China in the past 10 years.This paper provides a comprehensive review of the related findings of research on the mechanical properties of RAC in China.The influences of the RCA on the strength and deformation characteristics of concrete,the statistical characteristics for the strength of RAC,fracture energy,stress-strain relationships under uniaxial compression,uniaxial tension as well as pure shear,and the residual strength of RAC after exposure to high temperatures,the bond between RAC and different kinds of steel rebar were also reviewed.Furthermore,some recent studies on the numerical simulation of the failure mechanism for RAC at the meso-structure level were discussed.展开更多
A novel approach of iso-scallop trajectory generation for smooth manifold surfaces has been developed. Firstly,by defining homeomorphism mapping relations and differentiable structures,the smooth manifold surface is m...A novel approach of iso-scallop trajectory generation for smooth manifold surfaces has been developed. Firstly,by defining homeomorphism mapping relations and differentiable structures,the smooth manifold surface is mapped into several Euclidean planes,thus its trajectory generation can be decomposed into planar curve-filling tasks. Secondly,in the generation of direction-parallel trajectories,the calculation of the cutting interval and the curvature is given,depending on the generation of the first curve in the projection view. Thirdly,after automatic adherences of inverse projection curves,the filled curves are mapped into the original surface inversely to form trajectories. Although the required trajectories are iso-scallop,the trajectory intervals are variable according to the curvature changes at the projection point,which is advantageous to improving the trajectory quality. The proposed approach has appealing merits of dimensionality reduction,which decreases the algorithm complexity. Finally,numerical and machining examples are given to illustrate its feasibility and validity.展开更多
Erratum to:SCIENCE CHINA Life Sciences,November 2015 Vol.58 No.11:1084–1088doi:10.1007/s11427-015-4962-9In the first paragraph of the manuscript,the name of Charles Harrington was printed in error,should be Charles S...Erratum to:SCIENCE CHINA Life Sciences,November 2015 Vol.58 No.11:1084–1088doi:10.1007/s11427-015-4962-9In the first paragraph of the manuscript,the name of Charles Harrington was printed in error,should be Charles Sherrington.展开更多
文摘Spinal cord injuries(SCI)usually result in impairment of axonal conduction and sensorimotor function.There are no effective therapy to completely repair SCI.Axonal demyelination is very common as a pathologic change in SCI,and demyelination partly contributes to neural function impairment.So,it may be reasonable that remyelination of demyelinated axons become one of effective therapeutic targets for SCI treatment. Demyelination involves myelin breakdown and loss of myelin-forming cells(oligodendrocytes).The death of oligodendrocytes plays a key role in axonal demyelination in SCI.Recently a number of studies demonstrate that cell replacements could facilitate axonal remyelination and restore axonal conductive func- tion.Thus,it is expected that myelinogenetic cell transplantation(oligodendroglial lineage)will have good prospect as an effective therapy to improve axonal remyelination and restore neural function for SCI treat- ment in the near future.
基金supported by grants-in-aid for the National Core Research Center Program from MEST/KOSEF
文摘The friction coefficient between tube and die in guide zone of tube hydroforming was obtained. In hydroforming, the tube is expanded by an internal pressure against the tool wall. By pushing the tube through tool, a friction force at the contact surface between the tube and the tool occurs. In guiding zone, the friction coefficients between tube and die can be estimated from the measured axial feeding forces. In expansion zone, the friction coefficients between tube and die can be evaluated from the measured geometries of expanded tubes and FE analysis.
基金National Natural Science Foundation of China(No.51175413)
文摘In this paper,an elasto-viscoplastic three-dimension(3D) finite element model is developed to simulate the processing of bimetal tube with rotary swaging. Through simulation,the effects of high-frequency pulse stroking on the distribution and histories of stress,stain and loading are clarified. The stress in inner tube is compressive and higher than the minimum bonding force. Meanwhile,the stiffness of inner tube impacts outer tube extension in length.
文摘Some materials form better than others, moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another Configuration. The forming limit of a metal sheet is generally given in terms of the limiting principal strains under different loading conditions and represented by the so-called FLD （forming limit diagram）. In view of the difficulty to experimentally determine the forming limits, many researchers have sought to predict FLD. The formability of sheet metal has frequently been expressed by the value of strain hardening exponent and plastic anisotropy ratio. The stress-strain and hardening behaviour of a material is very important in determining its resistance to plastic instability. For these reasons, extensive test programs are often carried out in an attempt to correlate material formability with value of some mechanical properties. In this study, mechanical properties and the FLD of the AMS 5596 sheet metal was determined by using uniaxial tensile test and Marciniak＇s flat bottomed punch test respectively.
基金The project supported by National Natural Science Foundation of China under Grant Nos.10575036 and 10675046Natural Science Foundation of Zhejiang Province under Grant Nos.Y605476 and Y604027
文摘By using Total Routhian Surface （TRS） method the deformation of the nucleus ^160Yb is studied. The result shows that the triaxial superdeformed state exists with deformation parameters ε2 = 0.38 and γ = 21°, where proton shell correction energy plays a key role, and the sum of two quasi-proton particle energies gives an additional driving effect. The rotational energy also has an additional role in the formation of triaxial superdeformed.
基金support from the National Institute of Healththe Howard Hughes Medical Institute of the United States of America
文摘Since Caenorhabditis elegans was chosen as a model organism by Sydney Brenner in 1960's, genetic studies in this organism have been instrumental in discovering the function of genes and in deciphering molecular signaling network. The small size of the organism and the simple nervous system enable the complete reconstruction of the first connectome. The stereotypic developmental program and the anatomical reproducibility of synaptic connections provide a blueprint to dissect the mechanisms underlying synapse formation. Recent technological innovation using laser surgery of single axons and in vivo imaging has also made C. elegans a new model for axon regeneration. Importantly, genes regulating synaptogenesis and axon regeneration are highly conserved in function across animal phyla. This mini-review will summarize the main approaches and the key findings in understanding the mechanisms underlying the development and maintenance of the nervous system. The impact of such findings underscores the awesome power of C. elegans genetics.
基金supported by the National Natural Science Foundation of China (Grant No. 51178340)the Shanghai Science and Technology Committee (Grant No. 10231202000)the New Century Excellent Talentsin China Ministry of Education Project (Grant No. NCET-06-0383)
文摘Numerous experimental and theoretical studies on recycled aggregate concrete have been carried out in China in the past 10 years.This paper provides a comprehensive review of the related findings of research on the mechanical properties of RAC in China.The influences of the RCA on the strength and deformation characteristics of concrete,the statistical characteristics for the strength of RAC,fracture energy,stress-strain relationships under uniaxial compression,uniaxial tension as well as pure shear,and the residual strength of RAC after exposure to high temperatures,the bond between RAC and different kinds of steel rebar were also reviewed.Furthermore,some recent studies on the numerical simulation of the failure mechanism for RAC at the meso-structure level were discussed.
基金supported by the National Natural Science Foundation of China (Grant Nos.50835004,50905131)the Natural Science Foundation of Hubei Province (Grant No.2009CDB251)
文摘A novel approach of iso-scallop trajectory generation for smooth manifold surfaces has been developed. Firstly,by defining homeomorphism mapping relations and differentiable structures,the smooth manifold surface is mapped into several Euclidean planes,thus its trajectory generation can be decomposed into planar curve-filling tasks. Secondly,in the generation of direction-parallel trajectories,the calculation of the cutting interval and the curvature is given,depending on the generation of the first curve in the projection view. Thirdly,after automatic adherences of inverse projection curves,the filled curves are mapped into the original surface inversely to form trajectories. Although the required trajectories are iso-scallop,the trajectory intervals are variable according to the curvature changes at the projection point,which is advantageous to improving the trajectory quality. The proposed approach has appealing merits of dimensionality reduction,which decreases the algorithm complexity. Finally,numerical and machining examples are given to illustrate its feasibility and validity.
文摘Erratum to:SCIENCE CHINA Life Sciences,November 2015 Vol.58 No.11:1084–1088doi:10.1007/s11427-015-4962-9In the first paragraph of the manuscript,the name of Charles Harrington was printed in error,should be Charles Sherrington.
