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arXiv 1805.03332math.AP
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Poisson-Nernst-Planck方程稳态解的有限区域效应

Finite domain effects in steady-state solutions of Poisson-Nernst-Planck equations

Doron Elad, Nir Gavish

摘要:

研究了Poisson-Nernst-Planck模型在大而有限区域的渐近极限下的稳态解。利用积分的渐近匹配,我们得到了稳态状态方程的一个近似解,其误差与区域大小成指数关系。该近似用于量化有限域效应在整个参数空间上的程度。令人惊讶的是,已经为小的施加电压(几个热电压),我们发现,有限域效应是显着的,即使是大域(数百德拜长度的规模)。即,边界附近的解,即,边界层(双电层)结构对畴尺寸敏感,即使畴尺寸比边界层的特征宽度大许多倍。我们专注于这个中间制度之间的封闭域和“基本上无限”域,并研究如何域的大小影响的解决方案的性能。最后,我们提供了一个展望更高的尺寸与应用程序的离子通道和多孔电极。

英文摘要:

Steady-state solutions of the Poisson-Nernst-Planck model are studied in the asymptotic limit of large, but finite domains. By using asymptotic matching for integrals, we derive an approximate solution for the steady-state equation with exponentially small error with respect to the domain size. The approximation is used to quantify the extent of finite domain effects over the full parameter space. Surprisingly, already for small applied voltages (several thermal voltages), we found that finite domain effects are significant even for large domains (on the scale of hundreds of Debye lengths). Namely, the solution near the boundary, i.e., the boundary layer (electric double layer) structure, is sensitive to the domain size even when the domain size is many times larger than the characteristic width of the boundary layer. We focus on this intermediate regime between confined domains and `essentially infinite' domains, and study how the domain size effects the solution properties. We conclude by providing an outlook to higher dimensions with applications to ion channels and porous electrodes.

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