In unpowered trajectory of ballistic missiles,according to the role of air drag from its trajectory can be divided into freeflight trajectory and reentry trajectory in two parts.
在弹道导弹的被动段,根据受空气阻力的作用程度,其弹道可被分为自由段和再入段两部分。
参考来源 - 弹道导弹被动段弹道方程与仿真·2,447,543篇论文数据，部分数据来源于NoteExpress
文中运用了一种改进的球谐函数法，即换极法，大大简化了勒让德函数的递推计算，并进行了换极前后被动段扰动引力的仿真计算。
In this paper the improved method, also named transformation of the polar, is used to predigest the iterative calculation, and the simulation calculation has been progressed.
实验结果表明：盐酸氯丙嗪在各肠段的吸收均良好，药物在肠道内的吸收机制为被动扩散。
The results showed that CPZ was well absorbed in the whole intestinal segments, and the mechanism of its intestinal absorption was passive diffusion.
根据滚转火箭弹的动力学方程，给出了在弹体坐标系下无控低速滚转火箭弹在被动飞行段的锥形运动方程组。
The nonlinear coning motion equations in body coordinates on the force moment coefficients of low speed spinning rocket were obtained based on the dynamics equations.
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