English  |  正體中文  |  简体中文  |  全文筆數/總筆數 : 64745/64745 (100%)
造訪人次 : 20510858      線上人數 : 358
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
搜尋範圍 查詢小技巧:
  • 您可在西文檢索詞彙前後加上"雙引號",以獲取較精準的檢索結果
  • 若欲以作者姓名搜尋,建議至進階搜尋限定作者欄位,可獲得較完整資料
  • 進階搜尋


    請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/7300


    題名: 一價和多價叢集原子的熱穩定現象;Thermal stability of metallic clusters: mono- and polyvalent metals
    作者: 林文德;Wen-De Lin
    貢獻者: 物理研究所
    關鍵詞: 原子叢集;分子動力學;cluster;molecular dynamics
    日期: 2003-07-04
    上傳時間: 2009-09-22 10:54:40 (UTC+8)
    出版者: 國立中央大學圖書館
    摘要: 利用分子動力學的方法研究溫度對原子叢集的影響,和利用理論上的Gupta-type potential來表示原子之間的作用力,可以了解隨著不同的原子數,顯示出不同的熱力學特性,可以藉此來瞭解為何叢集原子系統不同於大體系統的原因。 The Brownian-type molecular dynamics simulation is re-visited and applied to study the thermal and geometric properties of four mono- and two polyvanent metallic clusters. For the thermal property, we report the specific heat at constant volume and study the solidlike-liquidlike transition by scrutinizing the characteristic of Cv For the geometric property, we calculate the relative root mean square bond-length fluctuation delta as a function of increasing temperature. The thermal change in delta reflects the movement of atoms and hence is a relevant parameter in understanding the phase transition in clusters. The simulated results for the Cv of alkali and aluminium clusters whose ground state structures exhibit icosahedral generally show one phase transition. In contrast, the tetravalent lead, even if predicted to be icosahedral at T=0 K, displays two phase transitions, a pre-melting process before undergoing the pregressive melting. In connection with the latter scenario, it is found here that those clusters identified to be lesser stable according to the second energy difference can qualitatively be classified to be the clusetrs with the possibility of undergoing pre-melting process. To delve further into the thermal behavior of clusters, we have analyzed also the thermal variation of delta(T) and attempted to correlate it with Cv(T). It turns out that the pre-melting or/and melting temperature of a cluster extracted from Cv do not always agree quantitatively with that drawing from delta . This implies that a quantitative understanding of the phase transformation in microstructures will need further effort to search for more useful cluster parameters.
    顯示於類別:[物理研究所] 博碩士論文

    文件中的檔案:

    檔案 大小格式瀏覽次數
    0KbUnknown543檢視/開啟


    在NCUIR中所有的資料項目都受到原著作權保護.

    社群 sharing

    ::: Copyright National Central University. | 國立中央大學圖書館版權所有 | 收藏本站 | 設為首頁 | 最佳瀏覽畫面: 1024*768 | 建站日期:8-24-2009 :::
    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - 回饋  - 隱私權政策聲明