Mg-6.75Zn-0.57Zr-0.4Y-0.18Gd(wt.%)sheet with typical basal texture was produced by cross rolling and annealing.Room temperature tensile tests were subsequently conducted along rolling direction(RD),transverse directio...Mg-6.75Zn-0.57Zr-0.4Y-0.18Gd(wt.%)sheet with typical basal texture was produced by cross rolling and annealing.Room temperature tensile tests were subsequently conducted along rolling direction(RD),transverse direction(TD),and diagonal direction(RD45).Deformation mechanism and orientation evolution during the tension were investigated by quasi-in-situ electron backscatter diffraction observation and in-grain misorientation axis analysis.The results indicate that the activation of deformation mechanism mainly depends on the initial grain orientation.For RD sample,prismatic<a>slip plays an important role in the deformation of grains with<0001>axis nearly perpendicular to the RD.With the<0001>axis gradually tilted towards the RD,basal<a>slip becomes the dominant deformation mode.After the tensile fracture,the initial concentrically distributed{0001}pole is split into double peaks extending perpendicular to the RD,and the randomly distributed{1010}pole becomes parallel to the RD.The evolution in{0001}and{1010}poles during tension is related to the lattice rotation induced by basal<a>slip and prismatic<a>slip,respectively.TD and RD45 samples exhibit similar deformation mechanism and orientation evolution as the RD sample,which results in the nearly isotropic mechanical properties in the annealed cross-rolled sheet.展开更多
The tensile deformation behavior and corresponding microstructure evolution of the Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr(at.%)magnesium alloy with long period stacking structure(LPSO)are studied by electron backscatter diffractio...The tensile deformation behavior and corresponding microstructure evolution of the Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr(at.%)magnesium alloy with long period stacking structure(LPSO)are studied by electron backscatter diffraction(EBSD)and slip lines methods.The results show that less and very small size of twins is observed in the grains with high value of Schmid factor for twinning,which indicates that the growth of the{10–12}twinning deformation is prevented by the LPSO phase.The prismatic lines present in grains of which the prismatic slip Schmid factor is above 0.4.The favorable orientation and LPSO phase synergistically promote the activation of prismatic slip.The inhomogeneous rotation of the grains during deformation is the reason for the microcrack at grain boundary.展开更多
Importance Cochlear implantation(CI)is an effective therapy for patients with severe to profound sensorineural hearing loss.It remains controversial whether children younger than 12 months of age should undergo CI.Obj...Importance Cochlear implantation(CI)is an effective therapy for patients with severe to profound sensorineural hearing loss.It remains controversial whether children younger than 12 months of age should undergo CI.Objective To evaluate the safety and effectiveness of CI in children younger than 12 months of age.Methods We performed a retrospective study of clinical data of pediatric patients younger than 12 months of age who underwent CI and were followed up for 1 to 2 years.Patients’developmental levels were evaluated by the Gesell score before CI.Intraoperative and postoperative complications were recorded to evaluate the safety of CI.Auditory and speech abilities were scored by the LittlEARS®auditory questionnaire(LEAQ),categories of auditory performance(CAP),speech intelligibility rating(SIR),infant‐toddler meaningful auditory integration scale(IT‐MAIS),and meaningful use of speech scale(MUSS)at 1,2,3,6,9,and 12 months after CI.The associations between clinical characteristics before CI and postoperative scores at 1 year after CI were analyzed by the linear mixed‐effects model.Results Eighty‐nine children(47 boys and 42 girls)were included in this study(mean age at CI,9.2±1.6 months).Sixteen patients were diagnosed with cochlear malformation and 16 underwent bilateral CI.No severe complications occurred in any patients.The mean developmental quotient of the Gesell score was 78.00±10.03.The median LEAQ scores were 0,5,10,16,22,26 and 30 before and at 1,2,3,6,9,and 12 months after CI,respectively.These findings implied that the LEAQ score greatly improved in the first year after CI.The overall CAP,SIR,IT‐MAIS,and MUSS scores also increased with increasing duration after CI.No significant associations were detected between clinical characteristics(age,sex,implant number,pre‐CI Gesell score,and inner ear malformation)and LEAQ outcomes at 12 months after CI.Interpretation With increasing duration after CI,auditory and speech behavior dramatically improve in young children.Our findings indicate that CI is feasible for children younger than 12 months of age.展开更多
基金the financial support from the National Natural Science Foundation of China(NSFC)with projects Nos.51874367,51574291.
文摘Mg-6.75Zn-0.57Zr-0.4Y-0.18Gd(wt.%)sheet with typical basal texture was produced by cross rolling and annealing.Room temperature tensile tests were subsequently conducted along rolling direction(RD),transverse direction(TD),and diagonal direction(RD45).Deformation mechanism and orientation evolution during the tension were investigated by quasi-in-situ electron backscatter diffraction observation and in-grain misorientation axis analysis.The results indicate that the activation of deformation mechanism mainly depends on the initial grain orientation.For RD sample,prismatic<a>slip plays an important role in the deformation of grains with<0001>axis nearly perpendicular to the RD.With the<0001>axis gradually tilted towards the RD,basal<a>slip becomes the dominant deformation mode.After the tensile fracture,the initial concentrically distributed{0001}pole is split into double peaks extending perpendicular to the RD,and the randomly distributed{1010}pole becomes parallel to the RD.The evolution in{0001}and{1010}poles during tension is related to the lattice rotation induced by basal<a>slip and prismatic<a>slip,respectively.TD and RD45 samples exhibit similar deformation mechanism and orientation evolution as the RD sample,which results in the nearly isotropic mechanical properties in the annealed cross-rolled sheet.
基金The authors would like to thank Key Project of ChineseNational Programs for Fundamental Research and Develop-ment(973 program)National Natural Science Foundationof China(NSFC)through project nos.2013CB632202 and 51574291 respectivelythe outstanding graduate project ofAdvanced Non-ferrous Metal Structural Materials and Manu-facturing Collaborative Innovation Center.`
文摘The tensile deformation behavior and corresponding microstructure evolution of the Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr(at.%)magnesium alloy with long period stacking structure(LPSO)are studied by electron backscatter diffraction(EBSD)and slip lines methods.The results show that less and very small size of twins is observed in the grains with high value of Schmid factor for twinning,which indicates that the growth of the{10–12}twinning deformation is prevented by the LPSO phase.The prismatic lines present in grains of which the prismatic slip Schmid factor is above 0.4.The favorable orientation and LPSO phase synergistically promote the activation of prismatic slip.The inhomogeneous rotation of the grains during deformation is the reason for the microcrack at grain boundary.
基金Special Fund of The Pediatric Medical Coordinated Development Center of Beijing Hospitals Authority(No.XTYB201828)the Capital Health Research and Development of Special Project(2016-1-5014)。
文摘Importance Cochlear implantation(CI)is an effective therapy for patients with severe to profound sensorineural hearing loss.It remains controversial whether children younger than 12 months of age should undergo CI.Objective To evaluate the safety and effectiveness of CI in children younger than 12 months of age.Methods We performed a retrospective study of clinical data of pediatric patients younger than 12 months of age who underwent CI and were followed up for 1 to 2 years.Patients’developmental levels were evaluated by the Gesell score before CI.Intraoperative and postoperative complications were recorded to evaluate the safety of CI.Auditory and speech abilities were scored by the LittlEARS®auditory questionnaire(LEAQ),categories of auditory performance(CAP),speech intelligibility rating(SIR),infant‐toddler meaningful auditory integration scale(IT‐MAIS),and meaningful use of speech scale(MUSS)at 1,2,3,6,9,and 12 months after CI.The associations between clinical characteristics before CI and postoperative scores at 1 year after CI were analyzed by the linear mixed‐effects model.Results Eighty‐nine children(47 boys and 42 girls)were included in this study(mean age at CI,9.2±1.6 months).Sixteen patients were diagnosed with cochlear malformation and 16 underwent bilateral CI.No severe complications occurred in any patients.The mean developmental quotient of the Gesell score was 78.00±10.03.The median LEAQ scores were 0,5,10,16,22,26 and 30 before and at 1,2,3,6,9,and 12 months after CI,respectively.These findings implied that the LEAQ score greatly improved in the first year after CI.The overall CAP,SIR,IT‐MAIS,and MUSS scores also increased with increasing duration after CI.No significant associations were detected between clinical characteristics(age,sex,implant number,pre‐CI Gesell score,and inner ear malformation)and LEAQ outcomes at 12 months after CI.Interpretation With increasing duration after CI,auditory and speech behavior dramatically improve in young children.Our findings indicate that CI is feasible for children younger than 12 months of age.