题目1：Spreading dynamics for a time-periodic nonlocal dispersal epidemic  model with delay and vaccination

主讲人：吴事良 教授

时间：2025年5月30日（周五）下午15：00

地点：理学院308会议室

主办单位：理学院

主讲人简介：

吴事良，西安电子科技大学数学与统计学院教授、博士生导师，陕西省科技创新团队带头人。现为中国数学会理事和陕西省数学会常务理事。主要研究方向为微分方程、动力系统及应用。完成国家自然科学基金三项和陕西省杰出青年科学基金一项，在研国家自然科学基金面上项目一项；获陕西省科学技术奖一等奖两项、二等奖一项(第一完成人)，及第十一届陕西青年科技奖。部分成果发表在J. Math Pures Appl.、Trans. Amer. Math. Soc.、SIAM J. Math Anal.、Calc. Var. Partial Differential Equations、J. Differential equations、Nonlinearity、J. Dynam. Differential Equations、J. Nonlinear Science等期刊。现任SCI期刊International Journal of Biomathematics的编委。

摘要:

In this talk, we investigate the spreading dynamics for a time-periodic nonlocal dispersal epidemic model with delay and vaccination. We first establish the spreading speed of the model and an abstract framework on the existence of time-periodic traveling waves, which will help us to derive the existence of the super-critical and critical time-periodic traveling waves. Then we show that the spreading speed coincides with the minimal waves speed of time-periodic traveling waves. Further, we consider the effects of delay, periodicity, nonlocality and vaccination on the spreading speed. In the absence of delay, we find a large class of the time-periodic systems that have the same spreading speed. When delay is introduced, some numerical simulations reveal that the spreading speed initially exhibits oscillatory behavior and ultimately converges to a constant as time-period increases.

题目2：Propagation dynamics for a stage-structured population model in a shifting environment

主讲人：赵晓强 教授

时 间：2025年5月30日（周五）下午16：00

地 点：理学院308会议室

主办单位：理学院

主讲人简介：

赵晓强，加拿大纽芬兰纪念大学数学与统计系教授，该校University Research Professorship荣誉获得者。赵教授先后于1983年和1986年在西北大学数学系获学士和硕士学位，1990年在中国科学院应用数学研究所获博士学位。赵教授长期从事动力系统、微分方程和生物数学相关领域的研究，在单调动力学、一致持久性、行波解和渐近传播速度、主特征值、基本再生数的理论及应用等方面的系列工作受到同行的广泛关注和引用。迄今为止，他已在“Comm. Pure Appl. Math.、 J. Eur. Math. Soc.、 J. reine angew. Math.、 J. Math. Pures Appl.、Trans. Amer. Math. Soc.、SIAM J. Math. Anal.” 等国际知名期刊上发表论文180余篇，并在Springer出版专著“Dynamical Systems  in Population Biology”。赵教授个人主页：https://www.math.mun.ca/~zhao/

摘要:

In this talk, I will report our recent research on an integro-difference system in an unbounded domain for a population with a stage structure consisting of juveniles and adults. The environment shifts between a favorite habitat and an unfavorite habitat at two ends of the domain, which makes the growth and propagation dynamics of the population depend on the changing habitat conditions. Under appropriate assumptions, we established the existence of spreading speeds and forced traveling waves for such a model. Our analysis of the propagation dynamics is based on the corresponding limiting systems at the far ends of the domain and their relation to the model. It turns out that the habitat shifting speed greatly influences the spreading speeds of the population and may even cause the extinction of the population.