标题： 一种Langevin动力学的数值玩具模型提供了胶体微滴蒸发的实时可视化 显示英文标题

标题： A numerical toy model of Langevin dynamics provides real-time visualization of colloidal microdroplet evaporation

摘要： 我们开发并测试了一种简化但通用的纳米颗粒聚集的数值模型，该模型使用了朗之万动力学。 该模型特别能够模拟蒸发（或冷凝）微滴中的聚集过程。 它在图形处理单元（GPU）上运行，这使其足够快，可以用于实时概念化任务。 我们通过在电磁陷阱中进行的两种实验结果验证了建模结果。 首先，我们的模型帮助我们阐明了在复合微滴蒸发过程中经常观察到的散射“恢复”现象。 此外，我们能够模拟我们的实验，其中微滴被干燥以形成纳米颗粒（NP）聚集体，然后进行软着陆。 因此我们可以将模型预测与扫描电子显微镜成像进行比较。 该模型测试了多达$2.5\times 10^5$种不同类型的纳米颗粒。 可以考虑多种类型的相互作用：粒子间：伦纳德-琼斯势和库仑力；外部：分散介质粘度、离心力、重力、表面张力和界面运动。 纳米颗粒的布朗运动可以自由控制。 核心程序配有后处理脚本，用于提取统计的纳米颗粒聚集体属性——分形维数和径向分布函数。 代码已发布在公共存储库中。 展示了多种不同的演化情景。 显示英文摘要

摘要： We have developed and tested a simplified but versatile numerical model of nanoparticles' aggregation using Langevin dynamics. The model is particularly capable of simulating aggregation in an evaporating (or condensing) microdroplet. It runs on a graphics processing unit (GPU), which makes it sufficiently fast for real-time conceptualization tasks. We have verified the results of modeling against the findings from two types of experiments we conducted in electrodynamic traps. Firstly, our model helped us to elucidate the phenomenon of scattering `revival', often observed during the evaporation of composite microdroplets. Further on, we were able to mimic our experiments, in which the microdroplets were dried up to form nanoparticle (NP) aggregates, and then soft-landed. Thus we could compare model predictions with SEM imaging. The model was tested for up to $2.5\times 10^5$ nanoparticles of several coexisting types. Several types of interactions can be accounted for: inter-particle: Lennard-Jones and Coulomb; external: dispersion medium viscosity, centrifugal force, gravity, surface tension, and interface movement. Brownian motion of nanoparticles can be freely controlled. The core program is accompanied by scripts extracting statistical NP aggregates properties in post-processing -- fractal dimension and radial distribution functions. The codes are made available in public repositories. Several diverse evolution scenarios are presented.