Bipolar junction transistors(BJTs) are often used in spacecraft due to their excellent working characteristics. However,the complex space radiation environment induces primary knock-on atoms(PKAs) in BJTs through coll...Bipolar junction transistors(BJTs) are often used in spacecraft due to their excellent working characteristics. However,the complex space radiation environment induces primary knock-on atoms(PKAs) in BJTs through collisions, resulting in hard-to-recover displacement damage and affecting the performance of electronic components. In this paper, the properties of PKAs induced by typical space heavy ions(C, N, O, Fe) in BJTs are investigated using Monte Carlo simulations. The simulated results show that the energy spectrum of ion-induced PKAs is primarily concentrated in the low-energy range(17eV–100eV) and displays similar features across all tested ions. The PKAs induced by the collision of energetic ions have large forward scattering angles, mainly around 88°. Moreover, the distribution of PKAs within a transistor as a function of depth displays a peak characteristic, and the peak position is linearly proportional to the incident energy at a certain energy range. These simulation outcomes serve as crucial theoretical support for long-term semiconductor material defect evolution and ground testing of semiconductor devices.展开更多
目的研究正常阴道分娩和选择性剖宫产对女性下尿路解剖和控尿功能的近期影响.方法选择2003年1～12月在我院作产前检查的24例孕妇为研究组,再进一步均分为正常阴道分娩亚组和选择性剖宫产亚组,以20名非妊娠健康女性为对照组.研究组于孕38...目的研究正常阴道分娩和选择性剖宫产对女性下尿路解剖和控尿功能的近期影响.方法选择2003年1～12月在我院作产前检查的24例孕妇为研究组,再进一步均分为正常阴道分娩亚组和选择性剖宫产亚组,以20名非妊娠健康女性为对照组.研究组于孕38～40周和产后6～8周、对照组于排卵期分别进行前庭超声和尿动力检查,分析尿道膀胱连接部移动度(UVJ-M)、静态最大尿道关闭压(MUCP)、功能性尿道长度(FL)和腹压漏尿点压(VLPP)在分娩前、后的变化以及与非妊娠女性的差异.结果各组VLPP均＞90 cm H2O.分娩前、后的UVI-M均较非妊娠女性明显增加(P＜0.01),分娩后均较分娩前轻度下降(P＞0.05),两种分娩方式分娩后UVJ-M的差异无显著性(P＞0.05).分娩后MUCP均较分娩前及非妊娠女性显著增加(P＜0.01),两种分娩方式分娩后MUCP的差异无显著性(P＞0.05).分娩前FL较非妊娠女性明显增加(P＜0.01),两种分娩方式分娩后FL的差异无显著性(P＞0.05),且与非妊娠女性的差异亦无显著性(P＞0.05).结论正常阴道分娩和选择性剖宫产近期内不降低女性下尿路的控尿功能,但是妊娠末期膀胱颈活动度明显增加,并持续到分娩后,是压力性尿失禁的危险因素之一,这种改变是否会随着时间而加重有待长期随访.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11974091,51973046,U22B2044,and 21673025)the Open Projects of State Key Laboratory of Intense Pulsed Radiation Simulation and Effect (Grant No.SKLIPR2020)。
文摘Bipolar junction transistors(BJTs) are often used in spacecraft due to their excellent working characteristics. However,the complex space radiation environment induces primary knock-on atoms(PKAs) in BJTs through collisions, resulting in hard-to-recover displacement damage and affecting the performance of electronic components. In this paper, the properties of PKAs induced by typical space heavy ions(C, N, O, Fe) in BJTs are investigated using Monte Carlo simulations. The simulated results show that the energy spectrum of ion-induced PKAs is primarily concentrated in the low-energy range(17eV–100eV) and displays similar features across all tested ions. The PKAs induced by the collision of energetic ions have large forward scattering angles, mainly around 88°. Moreover, the distribution of PKAs within a transistor as a function of depth displays a peak characteristic, and the peak position is linearly proportional to the incident energy at a certain energy range. These simulation outcomes serve as crucial theoretical support for long-term semiconductor material defect evolution and ground testing of semiconductor devices.
文摘目的研究正常阴道分娩和选择性剖宫产对女性下尿路解剖和控尿功能的近期影响.方法选择2003年1～12月在我院作产前检查的24例孕妇为研究组,再进一步均分为正常阴道分娩亚组和选择性剖宫产亚组,以20名非妊娠健康女性为对照组.研究组于孕38～40周和产后6～8周、对照组于排卵期分别进行前庭超声和尿动力检查,分析尿道膀胱连接部移动度(UVJ-M)、静态最大尿道关闭压(MUCP)、功能性尿道长度(FL)和腹压漏尿点压(VLPP)在分娩前、后的变化以及与非妊娠女性的差异.结果各组VLPP均＞90 cm H2O.分娩前、后的UVI-M均较非妊娠女性明显增加(P＜0.01),分娩后均较分娩前轻度下降(P＞0.05),两种分娩方式分娩后UVJ-M的差异无显著性(P＞0.05).分娩后MUCP均较分娩前及非妊娠女性显著增加(P＜0.01),两种分娩方式分娩后MUCP的差异无显著性(P＞0.05).分娩前FL较非妊娠女性明显增加(P＜0.01),两种分娩方式分娩后FL的差异无显著性(P＞0.05),且与非妊娠女性的差异亦无显著性(P＞0.05).结论正常阴道分娩和选择性剖宫产近期内不降低女性下尿路的控尿功能,但是妊娠末期膀胱颈活动度明显增加,并持续到分娩后,是压力性尿失禁的危险因素之一,这种改变是否会随着时间而加重有待长期随访.
