Collective Behavior and Spatiotemporal Dynamics in Chemical Systems

在这个由化学系化学结构、动力学和机制计划资助的项目中，西弗吉尼亚大学的Kenneth Showalter教授和他的学生将研究三个主要研究方向：(I)自推进粒子的动力学和集体行为，(Ii)降水反应中的传播目标和螺旋波，以及(Iii)耦合化学振荡器群体中的同步行为。在第一个项目中，研究了自推进颗粒群体中的集体行为，例如在过氧化氢溶液中的铂-二氧化硅颗粒，以确定颗粒间相互作用的机制。基于酶催化和表面催化反应的新型自推进颗粒系统正在被开发，并正在表征n-聚颗粒聚集体的运动。在第二个项目中，研究了最近发现的NaOH-AlCl3反应沉淀前沿的传播波。引起传播波行为的正反馈正在被描述，并正在发展表现出传播波的新的降水系统。第三个项目涉及对耦合化学振荡器的种群和网络的研究。在无催化剂的Belousov-Zhabotinsky反应混合物中，利用光敏的负载催化剂的粒子，对同步振子和非同步振子共存的嵌合体状态进行了实验和计算研究。此外，还研究了用脉冲时序相关塑性算法控制的振荡器仿生网络中的链路权重自优化问题。所有这三条线的研究都有望为化学系统中的集体行为和时空动力学提供新的重要信息，并为生物系统中的动态行为提供有价值的见解。对自推进粒子的研究将提供对生物单细胞生物体(如细菌和藻类)的推进和相互作用的机械见解。对目标波和螺旋波在降水系统中传播的研究将为化学波的传播提供新的机制，这种机制依赖于介质的结构特征，非常类似于许多生物系统中的波传播。同步和非同步耦合化学振子共存的新状态以及化学振子网络中的自优化研究为深入了解生命系统中普遍存在的基本动力学行为提供了新的视角。该研究项目预计将通过将研究和教学整合到大学课程中而产生广泛的本地影响。这项工作的影响通过国际理论物理中心参与的外联活动进一步扩大，这些活动将实践研究经验带给亚洲、非洲和中南美洲发展中国家的科学家。

In this project, funded by the Chemical Structure, Dynamics and Mechanisms Program of the Division of Chemistry, the Professor Kenneth Showalter of West Virginia University and his students will investigate three main lines of research: (i) the dynamics and collective behavior of self-propelled particles, (ii) the propagating target and spiral waves in precipitation reactions, and (iii) the synchronization behavior in populations of coupled chemical oscillators. In the first project, studies of collective behavior in populations of self-propelled particles, such as Pt-silica particles in hydrogen peroxide solutions, are carried out to determine the mechanism of inter-particle interactions. New self-propelled particle systems based on enzyme catalysis and surface catalyzed reactions are being developed and the motion of n-mer particle aggregates is being characterized. In the second project, studies of recently discovered propagating waves in the precipitation front of the NaOH-AlCl3 reaction are conducted. The positive feedback giving rise to the propagating wave behavior is being characterized and new precipitation systems exhibiting propagating waves are being developed. The third project involves studies of populations and networks of coupled chemical oscillators. The theoretically predicted chimera state, with coexisting subpopulations of synchronized and unsynchronized oscillators, is studied experimentally and computationally by using light-sensitive, catalyst-loaded particles in catalyst-free Belousov-Zhabotinsky reaction mixtures. Self-optimization of link weights in biomimetic networks of oscillators controlled with an algorithm for spike-timing dependent plasticity is also being studied. All three lines of research are expected to yield new and important information about collective behavior and spatiotemporal dynamics in chemical systems and offer valuable insights into dynamic behavior in biological systems. The studies of self-propelled particles will provide mechanistic insights into the propulsion and interaction of biological unicellular organisms, such as bacteria and algae. The studies of propagating target and spiral waves in precipitation systems will offer new mechanisms for chemical wave propagation that rely on structural features of the medium, much like wave propagation in many biological systems. The studies of new states of coexisting synchronized and unsynchronized coupled chemical oscillators and self-optimization in networks of chemical oscillators provide insights into basic dynamical behaviors pervasive in living systems. The research program is expected to have a broad local impact from the integration of research and teaching into the university curriculum. The impact of the work is further broadened through outreach activities involving the International Center for Theoretical Physics that bring hands-on research experiences to scientists in developing countries in Asia, Africa, and South and Central America.