我们基于Athena++磁流体动力学代码开发了尘埃多流体模块。该模块可以计算与气体耦合的任意数量的尘埃动力学行为。同时，我们设计了二阶精度全隐式求解器和尘埃浓度扩散的自洽处理方法，确保了尘埃-气体系统的伽利略不变性。该尘埃多流体模块与Athena++的现有功能相兼容，包括不同的曲线坐标系、网格细化，剪切盒子和快速轨道平流算法等。该模块特别有利于研究原行星盘中的气体-尘埃动力学和行星形成过程。 我们使用该尘埃多流体代码开展了多项研究工作，其中包括原行星盘中尘埃受气体湍流作用影响下的动力学行为。我们发现在原行星盘的垂直剪切不稳定性与罗斯贝波不稳定性的作用下，尘埃能够通过穿流不稳定性形成大质量的尘埃团块，促进原行星盘中的星子形成。 ​

超新星遗迹是恒星演化末期，发生爆炸后，抛射出来的恒星物质，以及爆炸时产生的激波与星际介质相互作用形成的结构。超新星遗迹被认为是银河系中“膝区”宇宙射线的一个重要来源。超新星爆炸把重元素（如铁、金等）送入星际空间。超新星遗迹可以通过其动力学过程影响周围介质的结构和演化。超新星遗迹N132D，是大麦哲伦星云中在X射线能段最亮的超新星遗迹。我们在N132D的两个位置测量了激波的膨胀的速度。其中一个区域由激波速度推导出的温度与从X射线能谱拟合得到的温度之间的明显差异可以通过离子和电子之间的温度部分平衡，绝热膨胀的冷却效应来解释。在另一区域这两个效应不能解释这种温度差异，因此我们讨论了宇宙线粒子加速解释这个差异的可能性。同时利用我们测量的激波半径和速度，以及激波一维演化模型，我们可以限制超新星遗迹周围介质的密度分布，超新星爆炸能量，以及抛射射物质量。

Introduction: Optimization and simulation are the most important analytical techniques, and this talk will provide a concise guide to optimization vs. simulation in decision-making. Specifically, we will start with an urban postal service redesign problem in Norway. Due to recent technological advancements, more diversified customer demand, and increasingly harder competition, a strategic reform of urban postal service systems was undertaken in Norway in 2013, called post-in-shop. Decisions need to be made to replace traditional post offices with small-sized postal service counters in retail stores to improve accessibility, operational efficiency, and cost-effectiveness. To solve this problem, a two-stage method is proposed. First, two location models are employed to determine the optimal facility locations, and a simulation model is then built to evaluate the urban postal service system with different location and demand allocation plans under a realistic and stochastic environment. This case study will show both the strengths and the weaknesses of optimization and simulation and how they can be complementarily applied in decision-making. Furthermore, some other application scenarios using combined simulation and optimization methods, e.g., waste management, vaccine distribution, and smart manufacturing, will be briefly introduced.