perfect differential

This model, based on a perfect group of partial differential equations, taking phase vectors as variables, is educed as a discrete one and, at last, is changed into real physics-space.

该模型从一组相空间中理想的偏微分控制方程出发，用相矢量为变量，导出其离散形式，再通过变换到实际的物理空间，得到最后要的电离层TEC参数的相空间解析预测模型。

By solving the nonlinear dynamic differential equations in perfect elastic collision process between a ball and a bar rotating about a fixed axis, this paper deals with the transformation of the kinetic energy and the potential energy of compressive deformation in the collision process.

通过求解球与定轴转动杆完全弹性碰撞过程的非线性动力学微分方程组，研究了碰撞过程中动能与压缩变形能之间的相互转换。

Caused to hear poorly or not at all. These quantities are not perfect differential.

使得听力微弱或者完全听不见。这些量不是全微分。

These quantities are not perfect differential.

这些量不是全微分.