Influence of heating effect in Thomson scattering diagnosis of laser-produced plasmas in air

A state diagnosis of laser-produced plasma in air generated by a 1064 nm pulse laser was investigated by the Thomson scattering(TS)method.The evolutions of the electron temperature and electron density were obtained as a function of the time delay which ranged from 300-3200 ns.The heating effect produced by the 532 nm probe beam with different energies on the air plasma at different interaction times was further studied using a time-resolved optical emission spectroscopy technique.The influence of the probe beam on the electron density was found to be negligible,whereas its influence on electron temperature is evident.In addition,the heating effect of the probe beam on the plasma strongly depends on the energy of the probe beam,and gradually weakens with increasing time delay.Our results are helpful for further understanding the TS method and its application in plasma diagnostics.

Measurement and analysis of the extreme ultraviolet emission band of laser-produced antimony plasmas

The temporal evolution of extreme ultraviolet(EUV)emission spectra of laser-produced antimony(Sb)plasmas has been measured in the 7-16 nm wavelength region using spatio?temporally resolved lase-produced plasma spectroscopy technique.The spectral profiles involve an intense quasi-continuous band with superimposed intense characteristic radiation and are different with the increase of delay time.The spectral structures were also analyzed according to Hartree-Fock calculations with configuration interaction effects and contributed from 4d^4/;4d-4p,and 4d-5f unresolved transition arrays of Sb7*-Sb131.A steady-state collisionalradiative model was used to estimate the electron temperature and density range of Sb plasmas.This work would enrich the spectral data of highly-charged ions and provided a possible selection for developing EUV light sources.

择期颈椎手术患者围术期发生主要不良心脏事件的影响因素

目的探讨择期颈椎手术患者围术期发生主要不良心脏事件(major adverse cardiac events,MACE)的影响因素。方法回顾性分析河北北方学院附属第一医院2017年3月至2021年3月收治的426例行择期颈椎手术患者的临床资料。收集患者的基本信息,包括性别、年龄、体质量指数(body mass index,BMI)、基础疾病,并根据基础疾病计算Charlson合并症指数(Charlson comorbidity index,CCI),收集术前血清肌钙蛋白I(cardiac troponin I,cTnI)水平和围术期MACE发生情况以及手术相关指标,包括颈椎手术类型、手术方式、入路方式、手术时间、麻醉时间、术中出血量、术后疼痛视觉模拟量表(visual analogue scale,VAS)评分、电解质紊乱情况。计数资料以例(%)表示,组间比较采用χ^(2)检验;应用Logistic回归模型对颈椎手术患者围术期发生MACE的影响因素进行多因素分析。结果426例患者中围术期发生MACE 54例(12.68%),其中不稳定型心绞痛4例(7.41%)、急性心肌梗死4例(7.41%)、严重心律失常33例(61.11%)、急性心力衰竭13例(24.07%)。多因素Logistic回归分析结果显示,年龄增加(50~59岁:比值比=1.34,95%置信区间:1.14~1.78;60~69岁:比值比=1.48,95%置信区间:1.20~1.86;70~79岁:比值比=1.71,95%置信区间:1.34~2.57;80~89岁:比值比=1.95,95%置信区间:1.46~2.85)以及女性、CCI评分>3分、术前cTnI>0.04μg/L、术后VAS评分>5分和电解质紊乱均为颈椎手术患者围术期发生MACE的影响因素(比值比分别为1.84、2.12、2.34、2.57、2.20,95%置信区间分别为1.34~2.68、1.50~3.41、1.63~3.72、1.53~4.01、1.43~3.69,均P<0.05)。结论择期颈椎手术患者围术期MACE的发生率较高,年龄增加、女性、高CCI评分、术前血清cTnI水平较高、术后疼痛和电解质紊乱均为择期颈椎手术患者围术期MACE发生的影响因素。