With the wide application of laser welding technology in automobiles and rail transportation, the non-destructive testing technology for laser welding seams is also getting better. Aiming at the laser welding seam of ...With the wide application of laser welding technology in automobiles and rail transportation, the non-destructive testing technology for laser welding seams is also getting better. Aiming at the laser welding seam of two-layer metal sheet below 3 mm, the possibility of laser welding seam detection by air-coupling ultrasonic detection technology is discussed. By numerical analysis and experimental analysis,Lamb wave is excited on aluminum plate in air. Through the propagation simulation of Lamb wave in laser weld specimen, the influence of laser weld width and weld quality on reflectivity and transmittance is analyzed. The propagation law of Lamb wave in laser weld specimen is clarified. The results show that the quality of laser weld can be evaluated by the mode of Lamb wave A0.展开更多
The laser generated ultrasound in solids in a thermoelastic regime is studied by solving thermoelastic wave equations. Analytic expressions of two-dimensional far-field ultrasonic displacements including the effects o...The laser generated ultrasound in solids in a thermoelastic regime is studied by solving thermoelastic wave equations. Analytic expressions of two-dimensional far-field ultrasonic displacements including the effects of thermal diffusion and optical penetration were obtained by means of the integral transform method. The meaning of the expressions is discussed. The effects of optical absorption coefficient on the directivity of laser generated ultrasound in non-metallic solids are also discussed. The directivity patterns of both longitudinal waves and shear waves are presented.展开更多
AIM:To assess the predictive value of baseline parameters of ultrasound biomicroscopy(UBM) for angle widening after prophylactic laser peripheral iridotomy(LPI) in patients with primary angle-closure suspect(PACS).MET...AIM:To assess the predictive value of baseline parameters of ultrasound biomicroscopy(UBM) for angle widening after prophylactic laser peripheral iridotomy(LPI) in patients with primary angle-closure suspect(PACS).METHODS:Angle-opening distance(AOD),trabecular iris angle(TIA),iris thickness,trabecular-ciliary process angle,and trabecular-ciliary process distance were measured using UBM performed before and two weeks after LPI.Iris convexity(IC),iris insertion,angulation,and ciliary body(CB) size and position were graded.Uni-and multivariate regression analyses were used to determine factors predicting the change in AOD(ΔAOD500,calculated as an angle width change before and after LPI) in all quadrants and in subgroup quadrants based on IC.RESULTS:In 94 eyes of 94 patients with PACS,LPI led to angle widening with increases in AOD500 and TIA(P<0.01).Multivariable regression analysis showed that IC(P<0.001),CB position(P=0.007) and iris insertion(P=0.049) were significantly predictive for ΔAOD500.All quadrants were categorized into extreme IC(27.8%),moderate IC(62.3%),and absent IC(9.9%) subgroups.The AOD500 increased by 220% and no other predictive factor was found in the extreme IC quadrants.The AOD500 increased by 55%,and baseline iris angulation was predictive for smaller changes in ΔAOD500 in the moderate IC quadrants.CONCLUSION:In PACS patients,quadrants with greater iris bowing predict substantial angle widening after LPI.Quadrants with a flatter iris,anteriorly positioned CB,and basal iris insertion are associated with less angle widening after LPI.Quadrants with iris angulation as well as a flatter iris configuration predict a smaller angle change after LPI.展开更多
目的:分析彩色多普勒超声在双波长激光治疗婴幼儿血管瘤的应用价值。方法:回顾性分析2021年3月至2023年3月收治的血管瘤患者临床资料,所有患者在行Cynergy双波长激光治疗前均接受彩色多普勒超声检查,根据不同的血流信号和皮损深度,观察...目的:分析彩色多普勒超声在双波长激光治疗婴幼儿血管瘤的应用价值。方法:回顾性分析2021年3月至2023年3月收治的血管瘤患者临床资料,所有患者在行Cynergy双波长激光治疗前均接受彩色多普勒超声检查,根据不同的血流信号和皮损深度,观察治疗效果及并发症发生情况。结果:198例血管瘤患儿纳入分析,共计212处皮损,其中根据血流信号分为无血流信号73例(34.3%)、稀少血流信号76例(35.8%)、中等血流信号63例(29.9%),有效率为100%,96.1%,85.7%,三组比较差异有统计学意义(P<0.05);根据皮损深度分为<1.2 mm 69例(32.5%),1.2~3.0 mm 88例(41.5%),>3 mm 55例(26.0%),有效率为100%,94.3%,83.6%,三组比较差异有统计学意义(P<0.05);在所有纳入的患者中,有21.7%的患儿出现不良反应。结论:彩色多普勒超声在双波长激光治疗婴幼儿血管瘤中具有重要的应用价值,可以实时监测治疗过程,并帮助临床医师预估疗效。展开更多
文摘With the wide application of laser welding technology in automobiles and rail transportation, the non-destructive testing technology for laser welding seams is also getting better. Aiming at the laser welding seam of two-layer metal sheet below 3 mm, the possibility of laser welding seam detection by air-coupling ultrasonic detection technology is discussed. By numerical analysis and experimental analysis,Lamb wave is excited on aluminum plate in air. Through the propagation simulation of Lamb wave in laser weld specimen, the influence of laser weld width and weld quality on reflectivity and transmittance is analyzed. The propagation law of Lamb wave in laser weld specimen is clarified. The results show that the quality of laser weld can be evaluated by the mode of Lamb wave A0.
文摘The laser generated ultrasound in solids in a thermoelastic regime is studied by solving thermoelastic wave equations. Analytic expressions of two-dimensional far-field ultrasonic displacements including the effects of thermal diffusion and optical penetration were obtained by means of the integral transform method. The meaning of the expressions is discussed. The effects of optical absorption coefficient on the directivity of laser generated ultrasound in non-metallic solids are also discussed. The directivity patterns of both longitudinal waves and shear waves are presented.
文摘AIM:To assess the predictive value of baseline parameters of ultrasound biomicroscopy(UBM) for angle widening after prophylactic laser peripheral iridotomy(LPI) in patients with primary angle-closure suspect(PACS).METHODS:Angle-opening distance(AOD),trabecular iris angle(TIA),iris thickness,trabecular-ciliary process angle,and trabecular-ciliary process distance were measured using UBM performed before and two weeks after LPI.Iris convexity(IC),iris insertion,angulation,and ciliary body(CB) size and position were graded.Uni-and multivariate regression analyses were used to determine factors predicting the change in AOD(ΔAOD500,calculated as an angle width change before and after LPI) in all quadrants and in subgroup quadrants based on IC.RESULTS:In 94 eyes of 94 patients with PACS,LPI led to angle widening with increases in AOD500 and TIA(P<0.01).Multivariable regression analysis showed that IC(P<0.001),CB position(P=0.007) and iris insertion(P=0.049) were significantly predictive for ΔAOD500.All quadrants were categorized into extreme IC(27.8%),moderate IC(62.3%),and absent IC(9.9%) subgroups.The AOD500 increased by 220% and no other predictive factor was found in the extreme IC quadrants.The AOD500 increased by 55%,and baseline iris angulation was predictive for smaller changes in ΔAOD500 in the moderate IC quadrants.CONCLUSION:In PACS patients,quadrants with greater iris bowing predict substantial angle widening after LPI.Quadrants with a flatter iris,anteriorly positioned CB,and basal iris insertion are associated with less angle widening after LPI.Quadrants with iris angulation as well as a flatter iris configuration predict a smaller angle change after LPI.
文摘目的:分析彩色多普勒超声在双波长激光治疗婴幼儿血管瘤的应用价值。方法:回顾性分析2021年3月至2023年3月收治的血管瘤患者临床资料,所有患者在行Cynergy双波长激光治疗前均接受彩色多普勒超声检查,根据不同的血流信号和皮损深度,观察治疗效果及并发症发生情况。结果:198例血管瘤患儿纳入分析,共计212处皮损,其中根据血流信号分为无血流信号73例(34.3%)、稀少血流信号76例(35.8%)、中等血流信号63例(29.9%),有效率为100%,96.1%,85.7%,三组比较差异有统计学意义(P<0.05);根据皮损深度分为<1.2 mm 69例(32.5%),1.2~3.0 mm 88例(41.5%),>3 mm 55例(26.0%),有效率为100%,94.3%,83.6%,三组比较差异有统计学意义(P<0.05);在所有纳入的患者中,有21.7%的患儿出现不良反应。结论:彩色多普勒超声在双波长激光治疗婴幼儿血管瘤中具有重要的应用价值,可以实时监测治疗过程,并帮助临床医师预估疗效。
