二元合金多晶粒的枝晶生长的等温相场模型

基于Ginzburg-Landau理论和单晶粒的枝晶生长模型，发展了一个单相场控制的多个晶粒的枝晶生长模型. 采用相场和溶质场耦合的方法，以Al-2%Cu合金为例模拟了二元合金等温凝固过程中多个晶粒的生长过程. 结果表明，这个模型的计算结果展现了多个晶粒枝晶的竞争生长，能较真实的再现凝固过程中的枝晶的生长过程.     

多柔体系统动力学符号演算的研究

多柔体系统动力学涉及繁杂的数学运算,对系统动力学方程和系数矩阵进行手工推导是低效而不可靠的．采用数值化方法进行系统动力学分析将包括许多虚运算和重复计算,使得计算效率和精度受到了影响．同时对约束和外力的变化适应性较差．本文在通用计算机符号演算软件ＭＡＴＨＥＭＡＴＩＣＡ环境下,研究了多柔体系统动力学的计算机符号演算方法,提出将多柔体系统动力学建模和数值分析的问题在ＭＡＴＨＥＭＡＴＩＣＡ环境中一体化解决,并通过实践说明这一方法是可行的和有效的．     

尼龙66-盐与碳纤维复合-固态缩聚的研究

本工作借助偏光显微镜,扫描电子显微镜和热分析方法(DSC,TGA)研究了尼龙66盐与碳纤维复合-固态缩聚反应历程及纤维-树脂之间的界面效应。发现对尼龙66盐的“原位固态缩聚”存有如碳纤维表面的成核结晶和催化效应之类的界面效应。讨论了碳纤维的界面效应对尼龙66基体的外延结晶和熔融行为及其热氧化稳定作用的影响。     

Multi-phase field simulation of competitive grain growth for directional solidification

The multi-phase field model of grain competitive growth during directional solidification of alloy is established. Solving multi-phase field models for thin interface layer thickness conditions, the grain boundary evolution and grain elimination during the competitive growth of SCN-0.24-wt% camphor model alloy bi-crystals are investigated. The effects of different crystal orientations and pulling velocities on grain boundary microstructure evolution are quantitatively analyzed. The obtained results are shown below. In the competitive growth of convergent bi-crystals, when favorably oriented dendrites are in the same direction as the heat flow and the pulling speed is too large, the orientation angle of the bi-crystal from small to large size is the normal elimination phenomenon of the favorably oriented dendrite, blocking the unfavorably oriented dendrite, and the grain boundary is along the growth direction of the favorably oriented dendrite. When the pulling speed becomes small, the grain boundary shows the anomalous elimination phenomenon of the unfavorably oriented dendrite, eliminating the favorably oriented dendrite. In the process of competitive growth of divergent bi-crystal, when the growth direction of favorably oriented dendrites is the same as the heat flow direction and the orientation angle of unfavorably oriented grains is small, the frequency of new spindles of favorably oriented grains is significantly higher than that of unfavorably oriented grains, and as the orientation angle of unfavorably oriented dendrites becomes larger, the unfavorably oriented grains are more likely to have stable secondary dendritic arms, which in turn develop new primary dendritic arms to occupy the liquid phase grain boundary space, but the grain boundary direction is still parallel to favorably oriented dendrites. In addition, the tertiary dendritic arms on the developed secondary dendritic arms may also be blocked by the surrounding lateral branches from further developing into nascent main axes, this blocking of the tertiary dendritic arms has a random nature, which can have aninfluence on the generation of nascent primary main axes in the grain boundaries.     

用透明电解槽研究镧,钕在氯化物熔盐中的溶解过程

采用透明电解槽技术首次观察了金属镧、钕分别在LaCl_3_KCl、NdCl_3+KCl以及KCl+NaCl熔盐中的溶解过程。实验发现镧、钕在各自熔盐中溶解时均产生黑色的金属雾。在电解条件下,镧、钕的溶解扩散受到很小的抑制。金属钕的溶解扩散明显快于金属镧的溶解扩散。形成的镧、钕金属雾主要由低价离子和部分金屈粒子(或原子)组成。     

差分电化学质谱方法（DEMS）的回顾：Ⅰ.DEMS原理和发展

差分电化学质谱是将电化学和质谱技术相结合而发展起来的一种现代榻化学现场测试手段，它可现场检测电化学反应中的挥发气体产物及动力学参数，中间体及其结构的性质等。     

尖晶石LiMn2O4锂充放电池的电化学研究

本文报导尖晶石型ＬｉＭｎ２Ｏ４化合物的制备方法，用循环伏安法和交流阻抗技术研究了Ｌｉ／有机电解液／ＬｉＭｎ２Ｏ４电池的电化学行为，用分形理论首次考察和进一步讨论电极材料的阻抗行为随锂离子嵌入或脱嵌电极时的变化。     

La和Nd在其氯化物熔体中的电化学腐蚀

稀土金属在其氯化物熔盐中的自腐蚀是导致电解制备稀土金属时电流效率降低的一个重要原因。但由于实验技术上的困难,有关这方面的研究报道不多。本文将在水溶液体系中常用的电化学弱极化测量腐蚀速度及电化学参数的方法用之于La、Nd在其氯化物熔盐体系中的腐蚀,表明同样适用。     

聚合硫酸铁钛混凝剂的制备及红外、紫外-可见光谱分析

复合混凝剂由于其具有优异的混凝性能而受到越来越广泛的关注,但与钛离子络合的铁基复合混凝剂的制备和表征还鲜有报道。研究以Ti(SO₄)₂为配合物,PO3-₄为稳定剂和络合剂制备了聚合硫酸铁复合混凝剂钛(PFTS)。主要利用红外光谱(FTIR)、紫外-可见光谱(UV/VIS)表征分析了PFTS在不同Ti/Fe,P/Fe,OH/Fe物料配比下对化学基团,分子结构变化的影响。结果表明,Ti4+和PO3-₄的加入,不是以单一离子形态存在,而是生成了诸如Ti—O,—Fe—P—Fe—和—Ti—P—Ti—等有助于增大聚合物分子量的基团键,而一定比例的Ti/Fe和P/Fe配比有助于物料单体相互络合生成诸如—Fe—P—Ti—的基团键和Fe₆(OH)6+₁₂,[Fe_x(OH)_y]₂H₂PO(6x-2y-1)+₄等类型的中聚体结构,此比例在P/Fe为0.2—0.3,Ti/Fe为1∶8比较恰当。过高的P/Fe比,Ti/Fe比和OH/Fe会生成TiO₂,Ti₃(PO₄)₄和FePO₄沉淀或高聚体络合物,不利于混凝性能的发挥。