Effect of the number of defect particles on the structure and dispersion relation of a two-dimensional dust lattice system

The effect of the number of defect particles on the structure and dispersion relations of a two-dimensional (2D) dust lattice is studied by molecular dynamics (MD) simulation. The dust lattice structures are characterized by particle distribution, nearest neighbor configuration and pair correlation function. The current autocorrelation function, the dispersion relation and sound speed are used to represent the wave properties. The wave propagation of the dust lattice closely relates to the lattice structure. It shows that the number of defect particles can affect the dust lattice local structure and then affect the dispersion relations of waves propagating in it. The presence of defect particles has a greater effect on the transverse waves than on the longitudinal waves of the dust lattice. The appropriate number of defect particles can weaken the anisotropy property of the lattice.     

Coupling strength effect on shot noise in boron devices

The shot noise properties in boron devices are investigated with a tight-binding model and the non-equilibrium Green’s function.It is found that the shot noise and Fano factors can be tuned by changing the structures,the size,and the coupling strength.The shot noise is suppressed momentarily as we switch on the bias voltage,and the electron correlation is significant.The Fano factors are more sensitive to the ribbon width than to the ribbon length in the full coupling context.In the weak-coupling context,the Fano factors are almost invariant with the increase of length and width over a wide bias range.     

graphene量子点的起伏效应对尺寸的敏感性研究

用第一原理研究了graphene量子点器件在不同尺寸时的输运特性,以得到起伏效应所引起的输运特性的变化,以及对尺寸的敏感性.研究结果表明无论电极与锯齿型边界的graphene量子点相连还是与扶手椅型边界的graphene量子点相连,都会受起伏效应较大的影响,并且随尺寸的不同影响程度也不同.加偏压后得到的电流也受较大影响,但两种连法受到的影响随尺寸的增加效果不同. 关键词： graphene 量子点 起伏效应     

多晶体级联钛宝石激光宽带三倍频

 用多块BBO晶体对钛宝石激光进行宽带三倍频, 比通常的两块晶体的方法效率上有所提高,实验研究了三倍频光的时间和空间特性,并从理论上分析了这种方法在激光带宽和效率等方面的优点,为ICF提高一种新的三倍频技术。     

光电反馈式静电悬浮与静电悬浮力测定

本文提出光电反馈式静电悬浮的新方法,简要讨论静电悬浮的原理、装置及其光电反馈控制过程.采用铝片和CD光盘作为悬浮体,测定了不同静电电压和不同悬浮间距时的静电悬浮力,揭示了它们之间的相互关系.结果显示这两种悬浮体均可获得足够的静电悬浮力,证明了静电悬浮的可行性.静电悬浮方法的显着特点是既适用于导电体与非导电体的悬浮,又适用于磁性体与非磁性体的悬浮,克服了传统磁悬浮技术仅适用于磁性体的局限性,可广泛应用于精密元器件的悬浮与非接触无损操作.     

弱时间简谐电场中类氢原子的变分微扰计算Ⅱ:激发态(21±1)和(32±2)

本文是文献[4]的续篇,采用基于Schrödinger方程流体动力学相似模型的变分微扰法计算了弱时间简谐电场中类氢原了H、He⁺、Li⁺²、Be⁺³、B⁺⁴激发态(21±1)和(32±2)的扰动波函数以及极化率与第一共振频率,讨论了电子云随时间的变化。结果表明,极化率与第一共振频率的计算值与精确值值符合得很好。结果再次表明,在应用变分微扰法计算极化率时,振幅微扰项∈与幅角项S是同等重要的。本文及文献[4]的工作部分地完成了Askar等人在文献[3]中宣布将要进行的工作。     

二乙酰分子内价轨道4ag+4bu的电子动量谱学研究

在高分辨率(△E＝1.15 eV,△p≈0.la.u.)电子动量谱仪上获得了二乙酰分子(diacetyl)最内价轨道4ag+4bu的电离能谱和动量谱的实验结果,并用Hartree-Fock和密度泛函理论方法做了理论计算.实验结果与理论计算符合较好.     

用离散变分方法计算几种原子的电子动量谱

用以密度泛函理论为基础的离散变分方法研究了氦原子、氩原子、钠原子和钾原子，分别得到了氦原子、氩原子、钠原子和钾原子动量空间的轨道电子云密度分布，并与实验值做了比较．     

脉冲激光对类金刚石（DLC）薄膜的热冲击效应研究

强激光辐照红外热像系统时，可造成系统的干扰和破坏，激光的波长不同，对系统的破坏效果也不同.为了保护红外系统窗口以及提高窗口的透过率，红外窗口广泛沉淀类金刚石（DLC）薄膜.当入射的激光波长位于红外系统响应波段外时，激光对系统的破坏首先是激光对DLC薄膜的破坏.以波长为1.06μm的激光为例，研究了脉冲激光对DLC薄膜的损伤机理，建立了DLC薄膜的热冲击效应模型，并通过求解热传导和应力平衡方程，得出了薄膜的温度场和应力场分布.理论分析表明，热应力破坏在脉冲强激光对DLC膜的损伤机理中占主导地位.当 辐照能量密度为E₀=100mJ·cm^-2时，在薄膜表面距光斑中心约 40μm区域内的压应 力明显超出其断裂强度，将造成膜层的剥离、脱落.理论分析与实验结果基本相符，表明建 立热冲击效应模型的正确性. 关键词： 激光辐照 类金刚石（DLC）薄膜 热冲击效应     

Investigation of outer valence orbital of CF2Cl2 by a new type of electron momentum spectrometer

Electronic states of CF2Cl2 （dichlorodifluoromethane, Freon 12） have been studied using a new type of electron momentum spectrometer with a very high efficiency at an impact energy of 1200 eV plus binding energy. The experimental electron momentum profiles are compared with the density functional theory （DFT） and Hartree-Fock （HF） calculations. The relationship between orbital assignments in different coordinate systems is discussed. A new method of difference analysis based on the new type of electron momentum spectrometer is used to clarify the ambiguities regarding the orbital ordering.