厄尔尼诺-南方涛动(El Nino and Southern Oscillation,ENSO)对全球气候都具有重要的影响,如印度洋季风、秘鲁沿岸的渔业生产以及北美的气候等.过去的研究在ENSO的观测、理论、预报和数值模拟等方面都取得了长足的进展,但依然有很多问...厄尔尼诺-南方涛动(El Nino and Southern Oscillation,ENSO)对全球气候都具有重要的影响,如印度洋季风、秘鲁沿岸的渔业生产以及北美的气候等.过去的研究在ENSO的观测、理论、预报和数值模拟等方面都取得了长足的进展,但依然有很多问题尚待解决.本文简要地回顾了过去在ENSO的相关理论、预报、非对称性以及年代际变化、古气候下的变化以及数值模拟方面的研究:首先回顾了ENSO盛行的几组理论,具体包括Bjerknes正反馈机制、延迟振子理论、充放电振子理论、平流反射振子理论以及西太平洋振子理论.其次,系统地总结了厄尔尼诺常用的预报方法以及预报因子(如暖水体积、西太平洋风场、印度洋-太平洋风场的积分及赤道流场等),并讨论了目前预报仍然存在的局限性;非对称性和年代际变化是ENSO重要的特征,本文详细地阐述了这方面的相关研究进展及存在的问题.再次,介绍了关于ENSO的古气候研究目前所取得的成果以及主要结论,并对数值模拟方面仍然存在的问题及ENSO对其他海盆的影响进行了讨论;最后,对上述相关方面存在的不足以及亟待解决的问题进行了探讨和总结.展开更多
In this paper, the changes of surface morphology, microstructure, hardness and corrosion resistance of industrial pure zirconium before and after surface modification by high current pulsed electron beam were discusse...In this paper, the changes of surface morphology, microstructure, hardness and corrosion resistance of industrial pure zirconium before and after surface modification by high current pulsed electron beam were discussed. The microstructure evolution and surface morphologies of the samples were characterized by using X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM). The experimental results show that sample by high current pulsed electron beam treatment surface melting, martensitic phase transformation occurred, and volcanic crater morphology and fine microstructure in the remelted layer surface;with the increase of number of pulses, after processing the microhardness of the samples also with the increase, 15-pulsed sample microhardness than the original sample increased by 30.9%. Corrosion resistance of samples was studied with the impedance diagram and polarization curve. The electrochemical results show that corrosion resistance of samples by high current pulsed electron beam treatment presents different degrees of change, the 5-pulsed sample in 1 mol HNO<sub>3</sub> solution corrosion of the best, and 15-pulsed sample corrosion resistance is even lower than the original sample. Grain refinement, martensite transformation, dislocation and deformation twins are the main reasons for improving the micro hardness and corrosion resistance of the samples.展开更多
目的:分析食管癌患者放疗期间预防性使用吡非尼酮对放射性肺炎的影响。方法:回顾性收集2017年11月至2020年1月于福建医科大学附属协和医院接受调强放疗(intensity-modulated radiation therapy,IMRT)的胸段食管癌患者资料,按是否使用吡...目的:分析食管癌患者放疗期间预防性使用吡非尼酮对放射性肺炎的影响。方法:回顾性收集2017年11月至2020年1月于福建医科大学附属协和医院接受调强放疗(intensity-modulated radiation therapy,IMRT)的胸段食管癌患者资料,按是否使用吡非尼酮将患者分为吡非尼酮组和对照组,通过逆概率处理加权法(inverse probability of treatment weighting,IPTW)将各协变量在两组人群进行加权处理,分析两组人群2级及3级以上放射性肺炎的发生率。结果:共纳入170例符合要求的病例,其中吡非尼酮组40例,对照组130例。中位随访时间22.6个月,通过对年龄、吡非尼酮用药史、放疗剂量、双肺V_(5)及V_(20)等可能影响放射性肺炎发生的临床因素及肺体积剂量参数等进行IPTW法加权分析,加权后两组基线特征标准化均值差值下降99.72%,两组2级以上、3级以上放射性肺炎发生率分别为3.92%vs.14.73%(P=0.0007)及3.92%vs.10.99%(P=0.0141),差异均有统计学意义。多因素Logistic回归分析发现吡非尼酮用药史(2级P=0.0017,3级P=0.0191)、年龄(2级P=0.0336,3级P=0.0028)、放疗剂量(2级P=0.0119,3级P=0.0031)均与2级和3级以上放射性肺炎相关。吡非尼酮组未发现明显的不良反应。结论:接受IMRT治疗食管癌患者,放疗期间同步使用吡非尼酮可有效降低2级及3级以上放射性肺炎的发生,安全性好,值得开展进一步临床研究证实。展开更多
文摘厄尔尼诺-南方涛动(El Nino and Southern Oscillation,ENSO)对全球气候都具有重要的影响,如印度洋季风、秘鲁沿岸的渔业生产以及北美的气候等.过去的研究在ENSO的观测、理论、预报和数值模拟等方面都取得了长足的进展,但依然有很多问题尚待解决.本文简要地回顾了过去在ENSO的相关理论、预报、非对称性以及年代际变化、古气候下的变化以及数值模拟方面的研究:首先回顾了ENSO盛行的几组理论,具体包括Bjerknes正反馈机制、延迟振子理论、充放电振子理论、平流反射振子理论以及西太平洋振子理论.其次,系统地总结了厄尔尼诺常用的预报方法以及预报因子(如暖水体积、西太平洋风场、印度洋-太平洋风场的积分及赤道流场等),并讨论了目前预报仍然存在的局限性;非对称性和年代际变化是ENSO重要的特征,本文详细地阐述了这方面的相关研究进展及存在的问题.再次,介绍了关于ENSO的古气候研究目前所取得的成果以及主要结论,并对数值模拟方面仍然存在的问题及ENSO对其他海盆的影响进行了讨论;最后,对上述相关方面存在的不足以及亟待解决的问题进行了探讨和总结.
基金the financial support from the National Natural Science Foundation of China(51878332,21976084,and 21925602)the Fundamental Research Funds for the Central Universities.
文摘In this paper, the changes of surface morphology, microstructure, hardness and corrosion resistance of industrial pure zirconium before and after surface modification by high current pulsed electron beam were discussed. The microstructure evolution and surface morphologies of the samples were characterized by using X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM). The experimental results show that sample by high current pulsed electron beam treatment surface melting, martensitic phase transformation occurred, and volcanic crater morphology and fine microstructure in the remelted layer surface;with the increase of number of pulses, after processing the microhardness of the samples also with the increase, 15-pulsed sample microhardness than the original sample increased by 30.9%. Corrosion resistance of samples was studied with the impedance diagram and polarization curve. The electrochemical results show that corrosion resistance of samples by high current pulsed electron beam treatment presents different degrees of change, the 5-pulsed sample in 1 mol HNO<sub>3</sub> solution corrosion of the best, and 15-pulsed sample corrosion resistance is even lower than the original sample. Grain refinement, martensite transformation, dislocation and deformation twins are the main reasons for improving the micro hardness and corrosion resistance of the samples.
文摘目的:分析食管癌患者放疗期间预防性使用吡非尼酮对放射性肺炎的影响。方法:回顾性收集2017年11月至2020年1月于福建医科大学附属协和医院接受调强放疗(intensity-modulated radiation therapy,IMRT)的胸段食管癌患者资料,按是否使用吡非尼酮将患者分为吡非尼酮组和对照组,通过逆概率处理加权法(inverse probability of treatment weighting,IPTW)将各协变量在两组人群进行加权处理,分析两组人群2级及3级以上放射性肺炎的发生率。结果:共纳入170例符合要求的病例,其中吡非尼酮组40例,对照组130例。中位随访时间22.6个月,通过对年龄、吡非尼酮用药史、放疗剂量、双肺V_(5)及V_(20)等可能影响放射性肺炎发生的临床因素及肺体积剂量参数等进行IPTW法加权分析,加权后两组基线特征标准化均值差值下降99.72%,两组2级以上、3级以上放射性肺炎发生率分别为3.92%vs.14.73%(P=0.0007)及3.92%vs.10.99%(P=0.0141),差异均有统计学意义。多因素Logistic回归分析发现吡非尼酮用药史(2级P=0.0017,3级P=0.0191)、年龄(2级P=0.0336,3级P=0.0028)、放疗剂量(2级P=0.0119,3级P=0.0031)均与2级和3级以上放射性肺炎相关。吡非尼酮组未发现明显的不良反应。结论:接受IMRT治疗食管癌患者,放疗期间同步使用吡非尼酮可有效降低2级及3级以上放射性肺炎的发生,安全性好,值得开展进一步临床研究证实。
