Simulation study on the formation and transition properties of cluster structures in liquid metals during rapid cooling processes

For the first time, a molecular dynamics simulation study has been performed for a liquid metal system consisting of 50000 atoms to deeply investigate the transitions of microstructure configurations dudng the rapid cooling processes. Especially, the cluster-type index method has been adopted to analyze the transforming and evolving processes of clusters and cluster configurations from liquid metal atoms. It has been found that the bigger cluster configurations in the system are formed by means of connecting some small clusters (they are combined by several smaller clusters), and not taken on the multi-shells configuration accumulated with an atom as the center and the surrounding atoms arranged according to some fixed pattern. With the decrease in temperature, the probability of repetitive appearance for clusters increases largely, which reveals that clusters are indeed possessing a certain relative stability and continuity (namely hereditary effect). These results will give us an important enlightenment to understand not only the forming mechanisms and microscopic processes of the short-order sections and disorder sparse sections in amorphous structures but also the freezing processes of liquid metals.``     

Access Grid网格环境下的可视化群组协同工作环境

Access Grid通常被称作访问网格，它是一种以开放网格服务体系结构(OGSA)为基础的，结合视频会议技术、网络技术和网格技术、建立起来的群组可视化交流环境。文章首先介绍了Access Grid系统的现状、体系结构、设计实现及其关键技术，然后以中科院网络中心(CNIC)的Access Grid结点建设为例，来阐述Access Grid群组协同工作环境的工作过程。最后，介绍了Access Grid与相关技术的结合和应用前景。