Lead zirconate titanate piezoelectric ceramics have important applications in space and aerospace technology,but the effect and physical mechanism of charged particle radiation on their performance yet to be clarified...Lead zirconate titanate piezoelectric ceramics have important applications in space and aerospace technology,but the effect and physical mechanism of charged particle radiation on their performance yet to be clarified.In this study,we characterized PbZr_(0.52)Ti_(0.48)O_(3)(PZT)thin films,and changes in the ferroelectric properties of the films before and after electron and proton irradiation were investigated.The natural and heat treatment recoverability of the ferroelectric properties were studied,and the damages and mechanisms of different types of radiation in PZT films were also investigated.The results show that,in addition to ionization damages,electron irradiation causes certain structural damage on the PZT film,and the large structural damage caused by proton irradiation reduces drastically the ferroelectricity of the PZT film.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51802056)the Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environmentsthe Key Laboratory of Micro-systems and Micro-structures Manufacturing(Harbin Institute of Technology),Ministry of Education,China。
文摘Lead zirconate titanate piezoelectric ceramics have important applications in space and aerospace technology,but the effect and physical mechanism of charged particle radiation on their performance yet to be clarified.In this study,we characterized PbZr_(0.52)Ti_(0.48)O_(3)(PZT)thin films,and changes in the ferroelectric properties of the films before and after electron and proton irradiation were investigated.The natural and heat treatment recoverability of the ferroelectric properties were studied,and the damages and mechanisms of different types of radiation in PZT films were also investigated.The results show that,in addition to ionization damages,electron irradiation causes certain structural damage on the PZT film,and the large structural damage caused by proton irradiation reduces drastically the ferroelectricity of the PZT film.
文摘目的探讨高原隧道钢筋工弯腰作业过程中下背部肌肉的表面肌电信号(surface electromyography,sEMG)特征及其与时间负荷和弯腰次数的相关性。方法选择高原某隧道4名男性钢筋作业人员,采用表面肌电仪实时采集其正常作业时左右竖脊肌群的sEMG,对其弯腰动作的时域指标均方根值(root mean square,RMS)和频域指标中位频率(mean frequency,MF)随负荷变化特征及其与时间和弯腰次数的相关性进行分析。结果4名钢筋工左、右竖脊肌的RMS均随时间和弯腰次数增加而上升;左竖脊肌RMS与时间相关系数分别为0.663、0.717、0.771和0.478,除4号钢筋工外均具显著统计学意义(P<0.01);右竖脊肌RMS与时间相关系数分别为0.908、0.488、0.782和0.929,除2号钢筋工外均具显著统计学意义(P<0.01);左竖脊肌RMS与弯腰次数相关系数分别为0.754、0.743、0.788和0.529,除4号钢筋工外均具显著统计学意义(P<0.01);右竖脊肌RMS与弯腰次数相关系数分别为0.796、0.456、0.778和0.877,除2号钢筋工外均具显著统计学意义(P<0.01)。4名钢筋工左、右竖脊肌MF均随时间和弯腰次数增加而下降,左竖脊肌MF与时间相关系数分别为-0.522、-0.904、-0.806和-0.493,除4号钢筋工外均具显著统计学意义(P<0.01);右竖脊肌MF与时间相关系数分别为-0.577、-0.873、-0.524和-0.836,均具显著统计学意义(P<0.01);左竖脊肌MF与弯腰次数相关系数分别为-0.486、-0.819、-0.813和-0.414,除4号钢筋工外均具显著统计学意义(P<0.01);右竖脊肌MF与弯腰次数相关系数分别为-0.516、-0.856、-0.515和-0.801,且均具显著统计学意义(P<0.01)。结论隧道钢筋工在弯腰作业时,左、右竖脊肌时域指标RMS和频域指标MF的变化与时间负荷以及弯腰次数有关,sEMG可以作为评价现场作业人员局部肌肉疲劳的一种客观方法。
