Hydride precipitation in zirconium cladding materials can damage their integrity and durability.Service temperature and material defects have a significant effect on the dynamic growth of hydrides.In this study,we hav...Hydride precipitation in zirconium cladding materials can damage their integrity and durability.Service temperature and material defects have a significant effect on the dynamic growth of hydrides.In this study,we have developed a phasefield model based on the assumption of elastic behaviour within a specific temperature range(613 K-653 K).This model allows us to study the influence of temperature and interfacial effects on the morphology,stress,and average growth rate of zirconium hydride.The results suggest that changes in temperature and interfacial energy influence the length-to-thickness ratio and average growth rate of the hydride morphology.The ultimate determinant of hydride orientation is the loss of interfacial coherency,primarily induced by interfacial dislocation defects and quantifiable by the mismatch degree q.An escalation in interfacial coherency loss leads to a transition of hydride growth from horizontal to vertical,accompanied by the onset of redirection behaviour.Interestingly,redirection occurs at a critical mismatch level,denoted as qc,and remains unaffected by variations in temperature and interfacial energy.However,this redirection leads to an increase in the maximum stress,which may influence the direction of hydride crack propagation.This research highlights the importance of interfacial coherency and provides valuable insights into the morphology and growth kinetics of hydrides in zirconium alloys.展开更多
目的:探讨脊髓造影与CT脊髓造影在退行性腰椎侧凸性椎管狭窄(degenerative lumbar stenosis with scoliosis,DLSS)中的诊断价值,并与MRI扫描、手术所见相比较。方法:选择2004-01/2007-06在北京协和医院骨科收治、并经手术证实的DLSS患...目的:探讨脊髓造影与CT脊髓造影在退行性腰椎侧凸性椎管狭窄(degenerative lumbar stenosis with scoliosis,DLSS)中的诊断价值,并与MRI扫描、手术所见相比较。方法:选择2004-01/2007-06在北京协和医院骨科收治、并经手术证实的DLSS患者97例。所有患者均经脊髓造影和CT脊髓造影观察,其中43例同时行MRI扫描。通过脊髓造影与CT脊髓造影的影像进行分析,确定其椎管狭窄部位、病变范围和病变程度,并与术中所见及MRI比较。结果:①脊髓造影与CT脊髓造影的表现:DLSS对硬膜囊或神经根的压迫较退行性腰椎管狭窄症复杂,除与关节突肥大增生、黄韧带肥厚、椎间盘退变突出有关外,还与关节突关节半脱位、椎弓根移位压迫神经根等因素有关。②与手术所见的符合率:脊髓造影、CT脊髓造影的诊断正确率分别为87.6%和92.8%,二者联合应用的诊断正确率为95.3%;对于不同弯度的DLSS,二者的诊断正确率无明显差异。③与MRI比较:在弯度较大的DLSS中,脊髓造影与CT脊髓造影的诊断正确率高于MRI。结论:脊髓造影和与CT脊髓造影的联合应用于DLSS诊断正确率较高,对于弯度较大的DLSS诊断正确率优于MRI。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.U2230401,U1930401,and 12004048)the National Key Research and Development Program of China (Grant No.2021YFB3501503)+1 种基金the Science Challenge Project (Grant No.TZ2018002)the Foundation of LCP。
文摘Hydride precipitation in zirconium cladding materials can damage their integrity and durability.Service temperature and material defects have a significant effect on the dynamic growth of hydrides.In this study,we have developed a phasefield model based on the assumption of elastic behaviour within a specific temperature range(613 K-653 K).This model allows us to study the influence of temperature and interfacial effects on the morphology,stress,and average growth rate of zirconium hydride.The results suggest that changes in temperature and interfacial energy influence the length-to-thickness ratio and average growth rate of the hydride morphology.The ultimate determinant of hydride orientation is the loss of interfacial coherency,primarily induced by interfacial dislocation defects and quantifiable by the mismatch degree q.An escalation in interfacial coherency loss leads to a transition of hydride growth from horizontal to vertical,accompanied by the onset of redirection behaviour.Interestingly,redirection occurs at a critical mismatch level,denoted as qc,and remains unaffected by variations in temperature and interfacial energy.However,this redirection leads to an increase in the maximum stress,which may influence the direction of hydride crack propagation.This research highlights the importance of interfacial coherency and provides valuable insights into the morphology and growth kinetics of hydrides in zirconium alloys.
文摘目的:探讨脊髓造影与CT脊髓造影在退行性腰椎侧凸性椎管狭窄(degenerative lumbar stenosis with scoliosis,DLSS)中的诊断价值,并与MRI扫描、手术所见相比较。方法:选择2004-01/2007-06在北京协和医院骨科收治、并经手术证实的DLSS患者97例。所有患者均经脊髓造影和CT脊髓造影观察,其中43例同时行MRI扫描。通过脊髓造影与CT脊髓造影的影像进行分析,确定其椎管狭窄部位、病变范围和病变程度,并与术中所见及MRI比较。结果:①脊髓造影与CT脊髓造影的表现:DLSS对硬膜囊或神经根的压迫较退行性腰椎管狭窄症复杂,除与关节突肥大增生、黄韧带肥厚、椎间盘退变突出有关外,还与关节突关节半脱位、椎弓根移位压迫神经根等因素有关。②与手术所见的符合率:脊髓造影、CT脊髓造影的诊断正确率分别为87.6%和92.8%,二者联合应用的诊断正确率为95.3%;对于不同弯度的DLSS,二者的诊断正确率无明显差异。③与MRI比较:在弯度较大的DLSS中,脊髓造影与CT脊髓造影的诊断正确率高于MRI。结论:脊髓造影和与CT脊髓造影的联合应用于DLSS诊断正确率较高,对于弯度较大的DLSS诊断正确率优于MRI。
