This kind of model could be written in ODE systems with small parameter.With singular perturbed method,the asymptotic expansion solution which is valid for the model was constructed.

• 采用了奇异摄动的方法，构造了关于小参数的幂级数展开，作为模型的形式渐近解，并用逐次逼近法证明了该解的一致有效性，从而可以将构造的解作为模型的近似解。