Propagation of Waves of Chemical Activity in Stratified Media

约翰·泰森得到了理论和计算化学计划的资助，对层状介质中化学活动的传播波进行理论研究。泰森将与帕维尔·K·布拉奇尼克合作，研究分层不均匀介质中的波传播，试图表征行波在层间边界的反射和折射。这项研究将通过分析、数值和实验技术进行。分析将通过两种互补的方法进行：运动学方法和奇异摄动理论。数值模拟还将利用互补的方法：对偏微分方程的标准有限差分近似，以及对可激发介质的元胞自动机建模。分析和数值结果将与分层化学可激发介质中波传播的实验观测相比较，即Belousov-Zhabotinsky反应。化学反应的行波在自然界中是不常见的，但并不少见。在燃烧化学、催化转化器、在肌肉组织中传播的膜去极化波、黏菌生长中产生循环AMP的波，以及表明精子受精的显著钙波中，都有大量的例子。化学波在均匀、各向同性介质中的传播研究已有多年。泰森的工作将是首次尝试研究分层非均匀介质中的波传播，分层非均匀介质是对重要生物系统更真实的模拟。

John Tyson is supported by a grant from the Theoretical and Computational Chemistry Program to perform theoretical studies of propagating waves of chemical activity in stratified media. In collaboration with Pavel K. Brazhnik, Tyson will study wave propagation in media with stratified inhomogeneities attempting to characterize the reflection and refraction of traveling waves at boundaries between layers. The study will be carried out by analytical, numerical, and experimental techniques. Analysis will be done by two complementary methods: the kinematic approach, and singular perturbation theory. Numerical simulation will also exploit complementary methods: standard finite-difference approximations to partial differential equations, and cellular automaton modeling of excitable media. The analytical and numerical results will be compared with experimental observations of wave propagation in a stratified chemical excitable medium, the Belousov-Zhabotinsky reaction. Traveling waves of chemical reaction are unusual but not uncommon occurrences in the natural world. Examples abound in combustion chemistry, catalytic converters, waves of membrane depolarization propagating through muscle tissue, waves of cyclic AMP production in slime mold growth, and a prominent Calcium wave signaling the fertilization of an egg by sperm. Chemical wave propagation has been studied for many years in homogeneous, isotropic media. Tyson's work would be the first attempt to study wave propagation in media with stratified inhomogeneities which are more realistic mimics of important biological systems.