a partial differential system的用法和样例：
- An effective method for solving a partial differential equation of secondary hydrocarbon migration is put forward.
- hyperbolic partial differential system
- An element is lumped if its terminal relation is an ordinary differential equation as opposed to a partial differential equation .
- Axisymmetric elasticity problem of cubic quasicrystal is reduced to a solution of a partial differential equation with higher-order by introducing displacement function.