While profile, the cross section was composed of annulus and rectangle, was extruded, the flow mechanism the plastic melt in the die was analyzed and the design method of die land was given.

本文分析了异型(圆环型与矩形的组合)材成型时塑料熔体在模头中的流动机理，并给出了模口成型长度的设计方法。

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According to the approximation of the velocity profile of turbulent flow in cylindrical pipes, flow rate measurement based upon the maximum velocity of circular cross-section is proposed.

根据已知圆管紊流流速分布的近似模地，研究了使用管道轴线处的最大流速测量流量的方法。

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