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连续相场模型在微观结构演化过程模拟中的应用 被引量:3
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作者 张刘超 卢艳丽 +1 位作者 陈铮 周影影 《材料导报》 EI CAS CSCD 北大核心 2013年第7期122-126,共5页
简要介绍了连续相场方法,包括:连续界面近似;有保守场变量和非保守场变量组成的相场变量;微观结构演化的化学驱动力,如体自由能、界面能、弹性畸变能、外场能量等;连续相场模型中的动力学方程,其中保守场变量在时间和空间上的演化遵循Ca... 简要介绍了连续相场方法,包括:连续界面近似;有保守场变量和非保守场变量组成的相场变量;微观结构演化的化学驱动力,如体自由能、界面能、弹性畸变能、外场能量等;连续相场模型中的动力学方程,其中保守场变量在时间和空间上的演化遵循Cahn-Hilliard的非线性扩散方程,非保守场变量遵循Allen-Cahn弛豫方程;动力学方程的常见数值解法。最后还简要介绍了几种常见的相场模型。 展开更多
关键词 连续相场模型 微观结构演化 扩散界面近似计算机模拟
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凝固过程晶粒生长动力学及拓扑转变机制的相场研究
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作者 卢艳丽 陈铮 +2 位作者 王永欣 杨晗 王永彪 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2014年第10期2377-2382,共6页
基于连续相场动力学模型,研究了凝固过程形核、长大及粗化阶段的组织形貌演化,动力学转变,以及粗化过程拓扑转变,分析了形核与长大过程的关系。研究结果表明,形核长大过程中,晶粒体积分数逐渐增大至平衡值,总表面积先增大后减小,体积自... 基于连续相场动力学模型,研究了凝固过程形核、长大及粗化阶段的组织形貌演化,动力学转变,以及粗化过程拓扑转变,分析了形核与长大过程的关系。研究结果表明,形核长大过程中,晶粒体积分数逐渐增大至平衡值,总表面积先增大后减小,体积自由能是形核的驱动力,表面能是形核的阻力。形核伴随着长大,两者是相互重叠相互竞争的两个过程。晶粒生长过程中,边数大于六的晶粒持续长大,而边数少于六的晶粒不断缩小。小晶粒消失机制有:临近切换机制;三边﹑四边及五边晶粒直接消失机制;四边交叉点分离并最终导致小晶粒消失机制;晶界直接消失机制。模拟结果与实验结果符合较好。 展开更多
关键词 多晶材料 凝固过程 形核长大 拓扑转变 连续相场
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A Comparative Study of Performance Between Operators With Work Discontinuity and Without Work Discontinuity 被引量:1
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作者 Josefa Angelie D. Revilla Iris Ann G. Martinez 《Chinese Business Review》 2014年第5期290-300,共11页
In situations where discontinuity in operation occurs, specifically in a country where coontractualization has an increasing trend, the performance level of operators after the work break is of great interest. Existin... In situations where discontinuity in operation occurs, specifically in a country where coontractualization has an increasing trend, the performance level of operators after the work break is of great interest. Existing studies have found that the performance of an operator declines after her operation is completely stopped. However, when the operator performed other tasks (may it be similar or not from her previous task) during the work break, the performance after the work break seems to be affected at different level. Contractual and regular operators from a semiconductor and textile company were considered to replicate a discontinuous and continuous operation. The processing times of contractual workers before and after several months of work break were compared. Two types of work break were seen to have significant effect on an operator's performance after the work break, Type 1: 0% to 40% similarity from previous task and Type 2: 40% to 97% similarity from previous task. One can find that when 21% of tasks performed during the work break are similar to the operator's previous task, there would be no change in her performance upon returning. On the other hand, a 5% decline in performance was observed after work break type 1 and an 8.54% improvement after work break type 2. Also, a remission rate of 18% from end of stint 1 to start of stint 2 under work break type 1 was seen, while 8% for work break type 2. This may also be true to other industries. Thus, further study is suggested. 展开更多
关键词 performance of contractual operators effects of work break remission rate
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Multipartite Entanglement Transfer from Multi-Mode Coherent State to Spin Qubits
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作者 任杰 朱士群 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第6期1035-1038,共4页
The multipartite entanglement transfer from continuous variable system to spin qubits is investigated. We select multi-mode coherent field as continuous variable field. It is found that the qubits can not gain tripart... The multipartite entanglement transfer from continuous variable system to spin qubits is investigated. We select multi-mode coherent field as continuous variable field. It is found that the qubits can not gain tripartite entanglement for states of close to GHZ state from the multi-mode coherent field. Moreover, the ability of the qubits gain the tripartite entanglement for states close to W state and bipartite entanglement from the continuous variable system is depended on the phase of multi-mode coherent field. 展开更多
关键词 entanglement transfer multi-mode coherent field
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