Micro- and macro-modeling of solidification process

Nagashima的团队提出了一种新的方法来测量熔融温度附近的扩散系数和粘度变化，这是传统方法难以测量的。该方法利用了分散在熔体中的细小颗粒的瑞利散射和布朗运动。在熔融温度附近，最大粘度和最小粘度之差增大，反映了液体结构的变化。Ohnaka的团队已经弄清楚了与氧化物高温超导体具有相似相图的有机材料体系的生长机理，并开发了一个微观模型，可以模拟这种生长现象。此外，他们还提出了一种新的固/液界面颗粒吞没机理。林的小组发展了一个动力学理论，考虑了过冷液体中无刻面自由枝晶生长的微观结构和凝固现象，也考虑了Th…的动力学理论在冷却壁面附近有更多的电子生长，伴随着温度松弛和固相粗化。这一理论是基于他们对铋锡合金凝固的实验工作。Tsukada的团队揭示了CZ法生长氧化物单晶的生长条件(炉膛结构和输运现象，包括晶体中的热应力)与晶体质量的关系，特别是微裂纹的关系。本工作基于对LiNbO_3单晶生长的数值模拟和实验观察。最后，Nakayama的团队使定量研究三维电路中所需的引线微型化成为可能。即发展了一种分析拉长薄熔体凝固过程的方法，并通过实验验证了他们的方法。这些工作进一步明确了微观模拟和宏观模拟的必要性，以及它们结合起来利用各种凝固工艺改进新材料和新器件的必要性，并发展了一些新的模拟方法。较少

Nagashima's groups has proposed a new method to measure diffusion coefficient and viscosity change near melting temperature, which is difficult to measure with conventional methods. This method uses Rayleigh scattering and Brownian motion of fine particles dispersed in melt. The possibility has been demonstrated for molten KNO_3 and NaNO_3. The data showed the difference between the maximum and minimum viscosity increases near the melting temperature reflecting liquid structure change. Ohnaka's group has made clear the growth mechanism of an organic materials-system which has the similar phase diagram of oxide high temperature superconductors, and developed a micro-model, which can simulate the growth phenomena. Further, they have proposed a new mechanism for particle engulfment at the solid/liquid interface. Hayashi's group has developed a kinetic theory considering microstructure and solidification phenomena for non-facetted free dendritic growth in undercooled liquid and also for th … More e growth near a cooled wall accompanying temperature relaxation and solid phase coarsening. The theory was based on their experimental work on the solidification of Bi-Sn alloy. Tsukada's group has revealed the relationship between growth condition (furnace structure and transport phenomena including thermal stress in crystals) and crystal quality especially micro-cracks for oxide single crystal growth by the CZ method. This work in based on numerical simulation and experimental observation of growth of LiNbO_3 single crystal. Finally, Nakayama's group has made it possible to investigate quantitatively the miniaturization of leads required in three dimensional electric circuits. Namely they developed a method to analyze the solidification process of elongating thin molten alloys and validated their method with experimental works.These works have made more clear the necessity of the micro- and macro-modeling and their combination to improve new materials and devices by using various solidification processes, and some new modeling methods have been developed. Less