【摘 要】
：
采用分子动力学方法对液态金属Na在四种不同冷速下的快速凝固过程进行了模拟跟踪研究.采用双体分布函数g(r)曲线、Honeycutt-Andersen键型指数法和原子团类型指数法对凝固过
论文部分内容阅读
采用分子动力学方法对液态金属Na在四种不同冷速下的快速凝固过程进行了模拟跟踪研究.采用双体分布函数g(r)曲线、Honeycutt-Andersen键型指数法和原子团类型指数法对凝固过程中微观结构的变化进行了分析.结果表明:冷却速率对微结构的转变有决定性影响,当冷速为1.0×1014和1.0×1013K/s时,系统形成以1551和1541键型或以缺陷多面体基本原子团(13 1 10 2)和二十面体基本原子团(12 0 12 0)为主体的非晶态结构;当冷速为1.0×1012和1.0×1011K/s时,系统则形成以1441和1661键型或以体心立方基本原子团(14 6 0 8)为主体的晶态结构.同时发现:不同冷速对液态金属Na在液态和过冷态时微观结构的影响甚小;但不同冷速对其固态(非晶态利晶态)时的微观结构有显著的影响,且要在液-固转变点(分别在玻璃转变温度Tg和晶化起始温度Tc)附近或以后才能充分展现出来.根据这一特点,有可能建立另一种确定液态金属Tg和Tc的新方法.原子团类型指数法比键型指数法更有利于研究液态、非晶态等无序体系和一些晶化体系的具体结构特征.
其他文献
利用有机大分子CTAB的自组装体为模板来调制正硅酸乙酯(TEOS)的水解缩聚,于气-液界面上制备出非担载的SiO2无机膜.对取膜时间进行了选择,考察了仿生制备SiO2膜过程中物料配比
Fractionations of rare earth elements (REEs) and the forming mechanisms in plants were studied using Triticum aestivum as plant material with application of exo
Herbal medicinal materials have been used worldwide for centuries to maintain health and to treat disease. However, adulteration of herbal medicines remains a m
The use of rare earth for inducing plant resistance was reviewed. The important developments in recent years were described, and rare earth can alleviate the po
In 2009, the Consortium for the Barcode of Life (CBOL) recommended the combination of rbcL and matK as the plant barcode based on assessments of recoverability,
Hydroxyapatite has a high affinity to biological macromolecules, especially to proteins. Bovine serum proteins were extracted to be used as stablizer to prepare
Half of altogether 60 cylindrical implant devices mode of titanium-aluminum-vanadium alloy( Ti-6Al-4 V) were plasma-sprayed with a hydroxyapatite-coating and th
μs脉冲电场诱导细胞产生的可逆电穿孔效应和不可逆电穿孔效应已有一定研究,但其所诱导的细胞凋亡效应却往往被忽略,诱导凋亡效应的脉冲电场与产生可逆/不可逆电穿孔效应脉冲
用密度泛函理论(densityfunctiontheory,DFT)和X射线近边结构(X-rayabsorptionnearedgestructure,XANES)模拟计算了不同酸度(pH=7.0,7.5和8.0)下Zn(II)在水锰矿表面的吸附.优