目的:利用医学影像构建个性化主动脉弓模型,对主动脉弓血流动力学特性进行较为系统的分析。方法:通过心脏三维图像得到包括小血管的较为完整的主动脉弓几何模型,采用Carreau黏度模型和其他控制方程建立主动脉弓血流动力学模型,通过有限...目的:利用医学影像构建个性化主动脉弓模型,对主动脉弓血流动力学特性进行较为系统的分析。方法:通过心脏三维图像得到包括小血管的较为完整的主动脉弓几何模型,采用Carreau黏度模型和其他控制方程建立主动脉弓血流动力学模型,通过有限元数值求解得到主动脉弓的血流动力学数值结果,并进行血流动力学特性分析。结果:降主动脉出口与入口流量之比为94.32%,其余小血管出口流量之和仅占5.68%;在大血管中,血流的压强并不是均匀分布的,不同点的压强之差在收缩期可能达到4.54 mm Hg(1 mm Hg=133.322 Pa);主动脉弓中剪切力最大处位于几个小血管分叉的上方;在收缩期的下降期主动脉弓大血管中涡流也非常明显。结论:该研究有助于加深对主动脉弓血流动力学特性的理解,对研究动脉血管疾病有一定的启发。展开更多
Honey was serially diluted with different percentages of glucose, fructose and water and each was analysed rheologically at room temperature of 27°C. Pure honey exhibits thixotropic time-dependent rheological beh...Honey was serially diluted with different percentages of glucose, fructose and water and each was analysed rheologically at room temperature of 27°C. Pure honey exhibits thixotropic time-dependent rheological behaviour, the behaviour of glucose and fructose solutions in water (a Newtonian solvent) tends towards near Newtonian. The rheological profiles of pure and adulterated honey samples were determined using RV DV-III Ultra Programmable Rheometer at low rates of share. A Structural Kinetic Model was developed which provided good correlations with the rheological data. The new model was used to classify samples using their average molecular weights as one of the distinguishing parameters. Also the order of the kinetics in the new model suggests the number of active components in the “honey” undergoing deformation as 3. Carreau-Yasuda model was also improved upon to provide an independent assessment of average molecular weight of samples.展开更多
文摘目的:利用医学影像构建个性化主动脉弓模型,对主动脉弓血流动力学特性进行较为系统的分析。方法:通过心脏三维图像得到包括小血管的较为完整的主动脉弓几何模型,采用Carreau黏度模型和其他控制方程建立主动脉弓血流动力学模型,通过有限元数值求解得到主动脉弓的血流动力学数值结果,并进行血流动力学特性分析。结果:降主动脉出口与入口流量之比为94.32%,其余小血管出口流量之和仅占5.68%;在大血管中,血流的压强并不是均匀分布的,不同点的压强之差在收缩期可能达到4.54 mm Hg(1 mm Hg=133.322 Pa);主动脉弓中剪切力最大处位于几个小血管分叉的上方;在收缩期的下降期主动脉弓大血管中涡流也非常明显。结论:该研究有助于加深对主动脉弓血流动力学特性的理解,对研究动脉血管疾病有一定的启发。
文摘Honey was serially diluted with different percentages of glucose, fructose and water and each was analysed rheologically at room temperature of 27°C. Pure honey exhibits thixotropic time-dependent rheological behaviour, the behaviour of glucose and fructose solutions in water (a Newtonian solvent) tends towards near Newtonian. The rheological profiles of pure and adulterated honey samples were determined using RV DV-III Ultra Programmable Rheometer at low rates of share. A Structural Kinetic Model was developed which provided good correlations with the rheological data. The new model was used to classify samples using their average molecular weights as one of the distinguishing parameters. Also the order of the kinetics in the new model suggests the number of active components in the “honey” undergoing deformation as 3. Carreau-Yasuda model was also improved upon to provide an independent assessment of average molecular weight of samples.
