Under the precondition of incompressible flow, fluid spiral motion in SK static mixer tube was resolved into axial beeline motion and circumferential rotation motion.

在流体不可压缩的假设前提下，将流体在SK型静态混合器中的螺旋形运动分解成轴向直线运动和环向旋转运动。

Results. Circumferential fusions exhibited significantly steeper motion gradients at the proximal adjacent level compared with TDR during flexion.

结果：屈曲时，外周融合与TDR相比，近侧相邻节段显示出的运动倾斜度明显较陡。