P(t)时,湖泊污染浓度将不断增大。在有效防控阶段,Pi(t)为单调递减函数,当Pi(t)
P (t), the pollution concentration of lakes will increase continuously. When Pi (t)
P(t)时,湖泊污染浓度将不断增大。在有效防控阶段,Pi(t)为单调递减函数,当Pi(t)
P (t), the pollution concentration of lakes will increase continuously. When Pi (t)