differential equation

Starting with Lagrange equations of the first kind, pure differential equations of multibody systems with rheonomic constraints are established.

根据变换方程与约束方程显含时间的价性，提出了定约束与定判据的同表述。

Axisymmetric elasticity problem of cubic quasicrystal is reduced to a solution of a partial differential equation with higher-order by introducing displacement function.

过引入位移函数使得立方准晶的轴对称弹性问题化为求解一高阶偏微分方程。