College of Humanities and Sciences Northeast Normal University Changchun 130117 P.R.China;
College of Mathematics Jilin University Changchun 130022 P.R.China;
College of Mathematics Jilin University Changchun 130022 P.R.China;
College of Mathematics Jilin Normal University Siping 136000 P.R.China;
Latent period; infected period; discontinuous treatment; globally stable; global convergence in finite time;