For the cyclic process of mass transfer in tray columns there are considered the hydrodynamic models of liquid flow during steam supply and during overflow of liquid from tray to tray. During steam supply, the hydrody...For the cyclic process of mass transfer in tray columns there are considered the hydrodynamic models of liquid flow during steam supply and during overflow of liquid from tray to tray. During steam supply, the hydrodynamic model is determined as perfect displacement model, and during liquid overflow, it is described as cell model. There were received the characteristics of liquid flow as follows： average residence time of liquid, degree of dispersion around the mean on the tray, number of perfect mixing cells depending on multiplication factor of exchange of liquid delay. In Y-X coordinates there is depicted a work line and theoretical stage of perfect displacement model. There were considered the conditions of mutual transfer of theoretical stage and theoretical stage with perfect displacement. The advantages of the mass transfer cyclic process to the stationary one arc stated.展开更多
目的:探讨三维可变反转角快速自旋回波(3D sampling perfection with application optimized contrasts using different flip angle evolution,3D-SPACE)序列在直肠癌术前T分期中的临床应用价值。方法:回顾性分析复旦大学附属肿瘤医院2...目的:探讨三维可变反转角快速自旋回波(3D sampling perfection with application optimized contrasts using different flip angle evolution,3D-SPACE)序列在直肠癌术前T分期中的临床应用价值。方法:回顾性分析复旦大学附属肿瘤医院2015年12月—2016年11月经肠镜活检确诊为直肠癌的患者,其术前未接受放化疗,但行直肠MRI检查。共收集178例,其中107例肿瘤轴位T2WI使用薄层小视野(field of view,FOV)T2WI序列(以下简称高分辨率T2WI序列),71例使用3D SPACE的T2WI序列(以下简称3D SPACE序列),并于2周内进行手术。将MRI所得T分期结果与病理结果进行对照分析,比较两种MRI技术评估直肠癌T分期的灵敏度、特异度、准确率。结果:高分辨率T2WI序列诊断T分期的总准确率为75.7%,3D SPACE序列诊断总准确率为83.0%。对早期T1、T2期的诊断准确率(T1:98.6%vs.88.8%;T2:87.3%vs.75.7%),3D SPACE序列均高于高分辨率T2WI序列;对T3期的诊断准确率,两者相当(85.9%vs.86.0%);而对T4期的诊断,3D SPACE序列优势不明显(95.8%vs.99.1%)。结论:3D SPACE序列可获得高信号比、高分辨率图像,提高直肠癌T分期的准确率,尤其对早期直肠癌的诊断有优势。展开更多
文摘For the cyclic process of mass transfer in tray columns there are considered the hydrodynamic models of liquid flow during steam supply and during overflow of liquid from tray to tray. During steam supply, the hydrodynamic model is determined as perfect displacement model, and during liquid overflow, it is described as cell model. There were received the characteristics of liquid flow as follows： average residence time of liquid, degree of dispersion around the mean on the tray, number of perfect mixing cells depending on multiplication factor of exchange of liquid delay. In Y-X coordinates there is depicted a work line and theoretical stage of perfect displacement model. There were considered the conditions of mutual transfer of theoretical stage and theoretical stage with perfect displacement. The advantages of the mass transfer cyclic process to the stationary one arc stated.
文摘目的:探讨三维可变反转角快速自旋回波(3D sampling perfection with application optimized contrasts using different flip angle evolution,3D-SPACE)序列在直肠癌术前T分期中的临床应用价值。方法:回顾性分析复旦大学附属肿瘤医院2015年12月—2016年11月经肠镜活检确诊为直肠癌的患者,其术前未接受放化疗,但行直肠MRI检查。共收集178例,其中107例肿瘤轴位T2WI使用薄层小视野(field of view,FOV)T2WI序列(以下简称高分辨率T2WI序列),71例使用3D SPACE的T2WI序列(以下简称3D SPACE序列),并于2周内进行手术。将MRI所得T分期结果与病理结果进行对照分析,比较两种MRI技术评估直肠癌T分期的灵敏度、特异度、准确率。结果:高分辨率T2WI序列诊断T分期的总准确率为75.7%,3D SPACE序列诊断总准确率为83.0%。对早期T1、T2期的诊断准确率(T1:98.6%vs.88.8%;T2:87.3%vs.75.7%),3D SPACE序列均高于高分辨率T2WI序列;对T3期的诊断准确率,两者相当(85.9%vs.86.0%);而对T4期的诊断,3D SPACE序列优势不明显(95.8%vs.99.1%)。结论:3D SPACE序列可获得高信号比、高分辨率图像,提高直肠癌T分期的准确率,尤其对早期直肠癌的诊断有优势。
