【摘要】 讨论了一个4维的时滞微分方程组,其中时滞τ表示一个固定的暂时的免疫期,即对于被接种的个体,经时间τ后又成了易感者.4个仓室分别为:易感者类,患急性病者类,患慢性病者类和被接种者类.通过一个无量纲化,将此模型转化成一个标准化模型,得到了它的基本再生数R0,用构造Liapunov泛函的方法得到了无病平衡位置稳定的条件.更多还原

【Abstract】 A four-dimension model with delay is constructed,where the discrete delay τ denotes a temporary immunity period of fixed length,after which the vaccinated individuals revert to the susceptible class.The total population is divided four compartments: susceptible,infectious acutely,infectious chronically and vaccinated.By discussing its normalized model,we obtain the stable conditions of the disease-free equilibium.更多还原