水分子在不同电荷态的重离子作用下的离化作用

运用舍时密度泛函理论和局域密度近似方法，计算了水分子H2O在速度为12．5a0／fs的重离子C^＋和C^2＋作用下产生的各种电荷态的水分子离子的几率，平均逃逸电子敷和偶极矩的变化随时间的演化，计算结果表明，在重离子势最大时，电偶极矩的变化最大；重离子远离分子时，重离子的电荷态越高，产生高电荷态分子的几率反而越小。     

碳分子线基态特性理论研究

从第一原理出发,利用密度泛函理论B3LYP系统研究了碳分子线Cn(n＝3～10)的电子结构特性.对优化结果分析发现,由于离域效应的作用,当n为奇数时,分子线基态为单重态,反之,当n为偶数时,三重态为其稳定的基态.对其电子结构分析可得,随着n的增加,体系能量逐渐降低;同时本文确定了分子线体系最高占据轨道HOMO能量EH、最低未占据轨道LUMO能量EL与n的关系式,即EHn-2＜EHn＜EHn+2,ELn-2＞ELn＞ELn+2.因而碳分子线的费米能级会表现出特有的奇偶性.该工作将有利于准确认识分子器件的伏安特性,设计出良好性能的分子器件.     

NUMERICAL ANALYSIS OF QUASICONFORMAL MAPPINGS BY CIRCLE PACKINGS

Thurston proposed that conformal mappings can be approximated by circle packing isomorphisms and the approach can be implemented efficiently. Based on the circle packing methods the rate of convergence of approximating solutions for quasiconformai mappings in the plane is discussed.     

Nonlocality Property of Three—Mode Correlated Fields

Four three-mode correlated states are generated by two beam splitters.We show that,by means of parity measurement,those light fields exhibit the nonlocality represented by the violation of the Bell inequality.The conditions fo the maximum violation are also studied.     

两类拟共形映射的掩盖定理

In this paper we define two classes of quasiconformal mappings,and study their covering properties by methods of module.We obtain some new results.In the meantime,we give new methods to prove Koebe 1/2 covering theorem on convex conformal mappings.     

超声波声孔效应中气泡动力学的研究

在超声快速制取组织细胞病理切片的过程中，发现激励信号对切片制取效果有明显的影响.为了掌握超声激励信号对组织细胞的影响规律，达到快速制取病理切片的最佳状态，从气泡空化模型入手，通过改变激励信号频率、声压、气泡初始半径和液体黏滞系数等参量，研究了声孔效应中气泡动力学激励机制.数值计算表明：空化泡振动随激励声压增强而升高，随液体黏滞系数增强而减弱；一定频率范围内空化泡振动能保持在膨胀、收缩和振荡的稳定空化状态，存在空化泡稳态振动的最佳激励频率；一定初始半径能保证空化泡产生稳定的振动，存在空化泡稳态振动幅度最大的初始半径.实际操作中，在频率、声压、初始半径和黏滞系数综合作用的若干空化阈内，声孔效应使超声快速法制取细胞组织切片获得最佳效果. 关键词： 声孔效应 超声空化 气泡振动 稳态空化域     

借形解题的几点注意

借形解题是以“形”研究“数”,它使我们可以借助直观,从整体上、本质上透视问题,十分有利于问题的解决.但是,如果忽视了图形的正确性、存在性、完整性和简洁性往往会使解题陷入困境或导致错误.1注意图形的正确性例1设t>0,求坐标平面上的两点A t 1t,t-1t,B(-1,0)之间的距离的最     

A New Holographic Entropy Bound from Conformal Field Theory at the Killing Horizon

A new holographic entropy bound is obtained by using conformal field theory at the Killing horizon.The entropy bound is tighter than the well-known bounds,such as the Bekenstein,Bekenstein-Mayo and‘t Hooft bounds.The result shows that the entropy of a system decreases when quantum effects are included.Therefore,the quantum effect will increase the degree of order of the system.