Numerical simulation and experiments were introduced to develop AA4045/AA3003 cladding billets with different clad-ratios. The temperature fields, microstructures and mechanical properties near interface were investig...Numerical simulation and experiments were introduced to develop AA4045/AA3003 cladding billets with different clad-ratios. The temperature fields, microstructures and mechanical properties near interface were investigated in detail. The results show that cladding billets with different clad-ratios were fabricated successfully. Si and Mn elements diffused across the bonding interface and formed diffusion layer. With the increase of clad-layer thickness, the interfacial region transforms from semisolid-solid state to liquid-solid state and the diffusion layer increased from 10 to 25 μm. The hardness at interface is higher than that of AA3003 side but lower than that of the other side. The bonding strength increased with the clad-layer thickness, attributing to solution strengthening due to elements diffusion. The cladding billets were extruded into clad pipe by indirect extrusion process after homogenization. The clad pipe remained the interfacial characteristics of as-cast cladding billet and the heredity of clad-ratio during deformation was testified.展开更多
The effect of high-speed direct-chill(DC) casting on the microstructure and mechanical properties of Al–Mg_2Si in situ composites and AA6061 alloy was investigated. The microstructural evolution of the Al–Mg_2Si com...The effect of high-speed direct-chill(DC) casting on the microstructure and mechanical properties of Al–Mg_2Si in situ composites and AA6061 alloy was investigated. The microstructural evolution of the Al–Mg_2Si composites and AA6061 alloy was examined by optical microscopy, field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). The results revealed that an increase of the casting speed substantially refined the primary Mg_2Si particles(from 28 to 12 μm), the spacing of eutectic Mg_2Si(from 3 to 0.5 μm), and the grains of AA6061 alloy(from 102 to 22 μm). The morphology of the eutectic Mg_2Si transformed from lamellar to rod-like and fibrous with increasing casting speed. The tensile tests showed that the yield strength, tensile strength, and elongation improved at higher casting speeds because of refinement of the Mg_2Si phase and the grains in the Al–Mg_2Si composites and the AA6061 alloy. High-speed DC casting is demonstrated to be an effective method to improve the mechanical properties of Al–Mg_2Si composites and AA6061 alloy billets.展开更多
Objective:To explore the effects of histone deacetylase 6(HDAC-6) on the PD cell model induced by proteasome inhibitor lactacystin.Methods:Human neuroblastoma SK-N-SH cells were cultured.The wild type pcDNA3.1-alpha-s...Objective:To explore the effects of histone deacetylase 6(HDAC-6) on the PD cell model induced by proteasome inhibitor lactacystin.Methods:Human neuroblastoma SK-N-SH cells were cultured.The wild type pcDNA3.1-alpha-synuclein eukaryotic expression plasmid was transferred into the cells which then were divided into control group,group L,group T and group T+L.The eells of group L were added with 5 umol/L lactacystin dissolved in dimethylsulfoxide(DMSO) to induce PD cell model with abnormal protein aggregation,the cells of control group were treated with 5 umol/L DMSO,the cells of group T were treated with 5 umol/L selective HDAC-6 inhibitor tubacin dissolved in DMSO,and the cells of group T+L were treated with 5 umol/L lactaeystin and 10 umol/L tubacin dissolved in DMSO.The expression levels of alpha-synuclein oligomers,HSP-27 and HSP-70 were detected by Western blot and the cell survival rate of all the groups was detected by MTT colorimetric assay,and compared 24 h after the cells were treated.Results:The expression levels of alpha-synuclein oligomers,HSP-27 and HSP-70 of the cells of group L were significantly higher than the control group,and the cell survival rate was significantly lower(P<0.05);the expression level of alpha-synuclein oligomers of the cells of group T+L was significantly higher than group L,but the expression level of HSP-27 and HSP-70 were significantly lower,and so as the cell survival rate(P<0.05);the differences of the expression level of alpha-synuclein oligomers,HSP-27 and HSP-70 and the cell survival rate of the cells of group T and the control group were not statistically significant(P>0.05).Conclusions:The expression level of alphasynuclein oligomers can be improved and the cell survival rate can be reduced by the PD cell model induced by lactacystin and treated with selective HDAC-6 inhibitor tubacin,which means that alpha-synuclein oligomers of the PD cell model induced by lactacystin can be inhibited and the cell survival rate can be improved by HDAC-6,and the mechanism may be related to the increased of HSP-27 and HSP-70.展开更多
基金Project(2015B090926013)supported by the Science and Technology Program of Guangdong Province,ChinaProject(20170540307)supported by the Natural Science Foundation of Liaoning Province,China
文摘Numerical simulation and experiments were introduced to develop AA4045/AA3003 cladding billets with different clad-ratios. The temperature fields, microstructures and mechanical properties near interface were investigated in detail. The results show that cladding billets with different clad-ratios were fabricated successfully. Si and Mn elements diffused across the bonding interface and formed diffusion layer. With the increase of clad-layer thickness, the interfacial region transforms from semisolid-solid state to liquid-solid state and the diffusion layer increased from 10 to 25 μm. The hardness at interface is higher than that of AA3003 side but lower than that of the other side. The bonding strength increased with the clad-layer thickness, attributing to solution strengthening due to elements diffusion. The cladding billets were extruded into clad pipe by indirect extrusion process after homogenization. The clad pipe remained the interfacial characteristics of as-cast cladding billet and the heredity of clad-ratio during deformation was testified.
基金financially supported by the Science and Technology Program of Guangzhou,China(No.2015B090926013)Postdoctoral Science Foundation of China(No.2015M581348)+1 种基金Postdoctoral Science Foundation of Northeastern University(No.20150302)the Doctoral Foundation of Chinese Ministry of Education(No.20130042130001)
文摘The effect of high-speed direct-chill(DC) casting on the microstructure and mechanical properties of Al–Mg_2Si in situ composites and AA6061 alloy was investigated. The microstructural evolution of the Al–Mg_2Si composites and AA6061 alloy was examined by optical microscopy, field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). The results revealed that an increase of the casting speed substantially refined the primary Mg_2Si particles(from 28 to 12 μm), the spacing of eutectic Mg_2Si(from 3 to 0.5 μm), and the grains of AA6061 alloy(from 102 to 22 μm). The morphology of the eutectic Mg_2Si transformed from lamellar to rod-like and fibrous with increasing casting speed. The tensile tests showed that the yield strength, tensile strength, and elongation improved at higher casting speeds because of refinement of the Mg_2Si phase and the grains in the Al–Mg_2Si composites and the AA6061 alloy. High-speed DC casting is demonstrated to be an effective method to improve the mechanical properties of Al–Mg_2Si composites and AA6061 alloy billets.
基金supported by Natural Science Foundation of Guangdong Province:(gd28182334)
文摘Objective:To explore the effects of histone deacetylase 6(HDAC-6) on the PD cell model induced by proteasome inhibitor lactacystin.Methods:Human neuroblastoma SK-N-SH cells were cultured.The wild type pcDNA3.1-alpha-synuclein eukaryotic expression plasmid was transferred into the cells which then were divided into control group,group L,group T and group T+L.The eells of group L were added with 5 umol/L lactacystin dissolved in dimethylsulfoxide(DMSO) to induce PD cell model with abnormal protein aggregation,the cells of control group were treated with 5 umol/L DMSO,the cells of group T were treated with 5 umol/L selective HDAC-6 inhibitor tubacin dissolved in DMSO,and the cells of group T+L were treated with 5 umol/L lactaeystin and 10 umol/L tubacin dissolved in DMSO.The expression levels of alpha-synuclein oligomers,HSP-27 and HSP-70 were detected by Western blot and the cell survival rate of all the groups was detected by MTT colorimetric assay,and compared 24 h after the cells were treated.Results:The expression levels of alpha-synuclein oligomers,HSP-27 and HSP-70 of the cells of group L were significantly higher than the control group,and the cell survival rate was significantly lower(P<0.05);the expression level of alpha-synuclein oligomers of the cells of group T+L was significantly higher than group L,but the expression level of HSP-27 and HSP-70 were significantly lower,and so as the cell survival rate(P<0.05);the differences of the expression level of alpha-synuclein oligomers,HSP-27 and HSP-70 and the cell survival rate of the cells of group T and the control group were not statistically significant(P>0.05).Conclusions:The expression level of alphasynuclein oligomers can be improved and the cell survival rate can be reduced by the PD cell model induced by lactacystin and treated with selective HDAC-6 inhibitor tubacin,which means that alpha-synuclein oligomers of the PD cell model induced by lactacystin can be inhibited and the cell survival rate can be improved by HDAC-6,and the mechanism may be related to the increased of HSP-27 and HSP-70.
