differential equation

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

根据变与约束显含时间的价性，提出了定常约束与定常系统判据的同表述。

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

本文通过引入位移函数使得立准晶的轴对称弹性问题化一高阶偏微分。