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arXiv 2009.10344cond-mat.mtrl-sci
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吸收强度的替代表示和晶体界面在辐射诱导气泡发展中的长期作用

Surrogate representation of sink strengths and the long-term role of crystalline interfaces in the development of irradiation-induced bubbles

Jing Luo, Yong Xin, Zhengcheng Zhou, Yichao Zhu, Xu Guo

摘要:

本文讨论了一个早期的尝试,用机器学习表示的代理模型代替速率方程中基于解析的汇强度项。在这里,我们强调,在多尺度建模的背景下,结合使用机器学习与尺度分析,通过它的一组精细分辨率的偏微分方程描述的(准稳定)短期个人汇行为的问题可以从平均场动力学渐近排序。因此,机器学习的训练是限制性的,也就是说,表达局部的和已经确定的,但分析上不可用的非线性函数关系之间的汇强度和其他局部连续场量。与训练的模型,一个是能够定量调查的偏见的影响所示的空隙/气泡是一个点缺陷汇,并与现有的研究情况下的结果进行了比较。此外,晶体界面上的更快的扩散机制是由局部平面速率方程来模拟的,它们与体扩散速率方程的联系是通过跨界面的点缺陷浓度的导数跳跃来制定的。因此,可以研究结晶界面作为部分汇和快速扩散通道的独特作用。方法上,目前的治疗也适用于研究更复杂的情况下观察到的长期汇行为的辐照材料。

英文摘要:

The present article addresses an early-stage attempt on replacing the analyticity-based sink strength terms in rate equations by surrogate models of machine learning representation. Here we emphasise, in the context of multiscale modelling, a combinative use of machine learning with scale analysis, through which a set of fine-resolution problems of partial differential equations describing the (quasi-steady) short-range individual sink behaviour can be asymptotically sorted out from the mean-field kinetics. Hence the training of machine learning is restrictively oriented, that is, to express the local and already identified, but analytically unavailable nonlinear functional relationships between the sink strengths and other local continuum field quantities. With the trained models, one is enabled to quantitatively investigate the biased effect shown by a void/bubble being a point defect sink, and the results are compared with existing ones over well-studied scenarios. Moreover, the faster diffusive mechanisms on crystalline interfaces are distinguishingly modelled by locally planar rate equations, and their linkages with rate equations for bulk diffusion are formulated through derivative jumps of point defect concentrations across the interfaces. Thus the distinctive role of crystalline interfaces as partial sinks and quick diffusive channels can be investigated. Methodologicalwise, the present treatment is also applicable for studying more complicated situation of long-term sink behaviour observed in irradiated materials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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