[1]School of Mathematics and Statistics Northeast Normal University Jilin 130024, P. R. China;
[2]School of Mathematical Science Huaiyin Normal University Huaian 223300, P. R. China;
[3]Department of MathematicsHarbin Institute of Technology Weihai 264209, P. R. China;
污染环境; 单种群模型; 生存分析; 随机; 平均值; 持久性; 单种群系统; 充分条件;