Hillock Sn whiskers in Sn0.3Ag0.7Cu solder are investigated in 20 seconds in corrosive climate(95% methanol and 5% nitric acid),and the growth mechanism of hillock Sn whiskers is studied.The results indicate that hill...Hillock Sn whiskers in Sn0.3Ag0.7Cu solder are investigated in 20 seconds in corrosive climate(95% methanol and 5% nitric acid),and the growth mechanism of hillock Sn whiskers is studied.The results indicate that hillock Sn whiskers are formed near the interface of Sn0.3Ag0.7Cu/Cu solder joints,and small corrosion pits provide conceive sites for Sn whiskers. Moreover,compressive stress induced by IMC reaction and oxidation for the whisker growth may be suggested as the driving force.展开更多
Background:Twin pregnancies continue to increase worldwide;however,the current clinical prenatal evaluation for the intrauterine growth of twins still relies on the growth standards of singletons.We attempted to estab...Background:Twin pregnancies continue to increase worldwide;however,the current clinical prenatal evaluation for the intrauterine growth of twins still relies on the growth standards of singletons.We attempted to establish a set of fetal biometric references for Chinese twin pregnancies,stratified by chorionicity and conception mode as spontaneously conceived monochorionic diamniotic(SC-MCDA),spontaneously conceived dichorionic diamniotic(SC-DCDA),and assisted reproductive technology dichorionic diamniotic(ART-DCDA)twins.Methods:From 2016 to 2019,the ultrasonographic fetal biometric measurements were longitudinally collected in pregnant women,including fetal weight,biparietal diameter,head circumference,abdominal circumference,femur length,and humerus length.The linear mixed models were used to test the difference of growth patterns between groups,and the growth curve of each biometric parameter was modeled by a generalized additive model for location scale and shape.Results:A total of 929 twin pregnant women and 2019 singleton pregnant women,met the inclusion criteria.Among twin pregnancies,148 were SC-MCDA,215 were SC-DCDA,and 566 were ART-DCDA twins.Overall,SC-DCDA twins grew faster than SC-MCDA twins,while slower than ART-DCDA twins(all P<0.05),and all of the three groups showed significant differences comparing with singletons,especially during the third trimester.Hence,the customized fetal growth charts of each fetal biometric parameter were,respectively,constructed for SC-MCDA,SC-DCDA,and ART-DCDA twins.Conclusions:The fetal biometric trajectories demonstrated characteristic patterns according to chorionicity and conception mode.To fill the gap,we modeled fetal biometric parameters for Chinese SC-MCDA,SC-DCDA,and ART-DCDA twin pregnancies,hoping to provide a reference for the further establishment of fetal growth reference values for Chinese twin fetuses.展开更多
基金Supported by the National Natural Science Foundation of China(No.51475220)the State Foundation of Laboratory of Advanced Brazing Filler Metals & Technology(Zhengzhou Research Institute of Mechanical Engineering)(No.SKLABFMT-2015-03)High Level Talent Plan of Jiangsu Normal University(No.YQ2015002)
文摘Hillock Sn whiskers in Sn0.3Ag0.7Cu solder are investigated in 20 seconds in corrosive climate(95% methanol and 5% nitric acid),and the growth mechanism of hillock Sn whiskers is studied.The results indicate that hillock Sn whiskers are formed near the interface of Sn0.3Ag0.7Cu/Cu solder joints,and small corrosion pits provide conceive sites for Sn whiskers. Moreover,compressive stress induced by IMC reaction and oxidation for the whisker growth may be suggested as the driving force.
基金grants from the National Natural Science Foundation of China(Nos.81673183,81874266,and 81971401)the Clinical Guidance Project of Shanghai Science and Technology Commission(No.164119622800).
文摘Background:Twin pregnancies continue to increase worldwide;however,the current clinical prenatal evaluation for the intrauterine growth of twins still relies on the growth standards of singletons.We attempted to establish a set of fetal biometric references for Chinese twin pregnancies,stratified by chorionicity and conception mode as spontaneously conceived monochorionic diamniotic(SC-MCDA),spontaneously conceived dichorionic diamniotic(SC-DCDA),and assisted reproductive technology dichorionic diamniotic(ART-DCDA)twins.Methods:From 2016 to 2019,the ultrasonographic fetal biometric measurements were longitudinally collected in pregnant women,including fetal weight,biparietal diameter,head circumference,abdominal circumference,femur length,and humerus length.The linear mixed models were used to test the difference of growth patterns between groups,and the growth curve of each biometric parameter was modeled by a generalized additive model for location scale and shape.Results:A total of 929 twin pregnant women and 2019 singleton pregnant women,met the inclusion criteria.Among twin pregnancies,148 were SC-MCDA,215 were SC-DCDA,and 566 were ART-DCDA twins.Overall,SC-DCDA twins grew faster than SC-MCDA twins,while slower than ART-DCDA twins(all P<0.05),and all of the three groups showed significant differences comparing with singletons,especially during the third trimester.Hence,the customized fetal growth charts of each fetal biometric parameter were,respectively,constructed for SC-MCDA,SC-DCDA,and ART-DCDA twins.Conclusions:The fetal biometric trajectories demonstrated characteristic patterns according to chorionicity and conception mode.To fill the gap,we modeled fetal biometric parameters for Chinese SC-MCDA,SC-DCDA,and ART-DCDA twin pregnancies,hoping to provide a reference for the further establishment of fetal growth reference values for Chinese twin fetuses.
