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Taylor补丁对新型动脉旁路移植流场影响的数值分析 总被引:1,自引:0,他引:1
为了研究Taylor补丁对新型(S型)动脉旁路移植术中吻合口处流场的影响,使用数值方法研究了采用Taylor补丁和未采用该补丁的两个S型旁路移植模型内流场的血流动力学差异. 对流速、壁面切应力和切应力梯度等参数进行了比较分析. 结果表明,Taylor补丁对吻合口的流场有显著影响. 采用Taylor补丁的模型其下游吻合口处的流场分布较未采用补丁的模型更均匀,二次流平均流速减小约34.48%,壁面切应力梯度减小约52.22%,从壁面切应力梯度方面分析,这将有助于改善血流动力学分布,抑制动脉粥样硬化. 但从壁面切应力值分析,其动脉底部的壁面低切应力区明显增大,平均壁面切应力值减小30.33%,这又将促使动脉粥样硬化. 因此,Taylor补丁是否对S型搭桥术具有治疗优越性,仅从血流动力学分析尚不能定论,配合数值计算结果进行动物和临床实验研究是十分必要的. 相似文献
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The electronic and optical properties of monoclinic and rhombohedral V2O3 are investigated in the framework of density functional theory (DFT) and GGA+U. It is found that, the metal-insulator transition (MIT) in V2O3 is induced by the on-site correlation effect, accompanied with a distinct orbital occupation change. The MIT is independent of the structural transition. The theoretical energy gap 0.6 eV agrees with the experimental value of 0.66±0.05 eV very well. Subsequently, the optical properties are also investigated. Interestingly, the insulating V2O3 shows minimal absorption in the infrared region, but the metallic V2O3 becomes opaque in such region. Therefore, a threshold at about 1 eV interprets the experimental charge gap (Perucchi et al., 2009) theoretically. Such infrared thermochromism makes it a potential candidate for several optical applications. 相似文献
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