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A stochastic logistic model with delays and impulsive perturbation is proposed and investigated. Sufficient conditions for extinction are established as well as nonpersistence in the mean, weak persistence and stochastic permanence. The threshold between weak persistence and extinction is obtained. Furthermore, the theoretical analysis results are also derivated with the help of numerical simulations. 相似文献
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通过引入白噪声,提出了一类具有随机扰动的经典竞争系统,并对其生存分析进行了研究.不仅给出了保证灭绝性和弱持久性的充分条件,还得到了弱持久性和灭绝性之间的阀值.最后,给出数值模拟验证了理论分析结果. 相似文献
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In this paper, we investigate a discrete semi-ratio dependent predator-prey system with Holling IV type functional response. For general nonautonomous case, sufficient conditions which ensure the permanence and the global stability of the system are obtained. Meanwhile, we discuss the existence of the positive periodic solution and global stability of the system. 相似文献
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无溶剂热分解单源前驱体法制备有机单分子层表面修饰NiS纳米微粒 总被引:2,自引:0,他引:2
纳米微粒由于具有很多特别的物理和化学性质,在光、电、磁、机械等各个领域显示出了广阔的应用前景,所以纳米微粒的制备与性能研究是近年来化学、物理和材料科学中最热门和最前沿的课题之一。尽管目前有多种纳米微粒的制备方法见诸文献报道,但是新的纳米微粒的制备方法依然是人们追求的目标之一。无溶剂合成纳米材料是近年来开始研究的制备纳米材料的新方法,在无溶剂环境中,微粒之间的碰撞基本不发生,微粒生长过程是通过单体加成来实现的,这样就较易得到形状和尺寸单分散的纳米材料。但是采用无溶剂合成纳米材料时通常需要加入捕获剂来控制… 相似文献
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