纸状显示器

常见的显示器有阴极射线管和液晶显示器 ,它们已分别应用在示波器、电视机、计算机、计算器、通信设备 (雷达、呼机、手机等 )等方面 .此外 ,还有等离子体显示器 ,用这种显示器做成的电视机 ,整机厚度只有大约 3— 4ｃｍ .最近 ,日本佳能公司的工程技术人员研制出了纸状显示器 .所谓纸状显示器就是一种薄如纸、柔性大的反射式显示器 ,它所显示的图像在没有电源输入时仍能存在 .这种显示器的显示机制 ,依据的是电泳现象 .研究人员想把常规的显示器(液晶显示器、阴极射线管 )的优点和这种纸状显示器的优点结合起来 .这类显示器已有人提出过并…     

镍掺杂ZnO的半金属铁磁性质和光学性质的研究

采用基于局域密度泛函理论的第一原理平面波超软膺势法,研究了纯净ZnO和Ni掺杂ZnO后的能带结构、电子态密度以及光学性质,结果表明:Ni掺杂ZnO后存在自旋极化,体系表现出半金属铁磁性质,可以实现自旋极化载流子的注入,并且在可见光区和紫外光区(1.98 eV～5.61 eV)的吸收系数显著提高.     

Cu_3N弹性和热力学性质的第一性原理研究

利用基于密度泛函理论的第一性原理全势线性缀加平面波方法,研究了立方反ReO3结构Cu3N在零温(0K)零压下的平衡晶格常数、体弹模量及其对压强的一阶导数,计算结果与其他实验及理论结果基本相符.同时得出Cu3N的弹性常数,Poisson比等,并分析出Cu3N在零温零压下是稳定的.通过准谐Debye模型计算Cu3N的热力学性质,得到了Cu3N的晶格常数、等压比热容、等容比热容、热胀系数与温度和压强之间的关系,同时计算出不同温度不同压强下其体弹模量及Debye温度的值。     

BeO高压相变和声子谱的第一性原理计算

采用第一性原理方法计算了BeO在零温时的高压相变和三种结构在零温零压时的声子谱.相变的计算表明,在122GPa左右的压力下BeO会发生从纤锌矿(B4)结构到氯化钠(B1)结构的相变,而闪锌矿(B3)结构在零温零压下是一种可能的亚稳态结构.采用冷声子方法计算了这三种结构的BeO在零温零压下的声子谱.计算结果表明:B1结构在零温零压下是一种不稳定的结构;尽管B4结构和B3结构具有明显的相似性,仍然可以通过声子谱来很好的区分.最后根据准简谐近似理论计算得到了BeO的高温高压相图.     

ScH_2分子的结构及分析势能函数

本文利用相对论有效原子实(RECP)和密度泛函(B3LYP)的方法对Sc原子采用SVP基组,对H原子采用6-311++G基组,对ScH_2分子的结构进行了优化,得到了它的平衡几何构型和谐振频率.使用多体项展式理论方法,导出了基态ScH_2分子的分析势能函数,该势能表面准确地再现了ScH_2(C_(2v))平衡结构,然后根据势能函数等值图讨论了反应势能面的静态特征,并利用杂化轨道理论解释了ScH_2分子的结构.     

单晶ZnO、TiO_2纳米线拉伸力学特性的分子动力学研究

采用分子动力学方法,模拟了不同加载速度、不同温度下单晶ZnO、TiO_2纳米线的拉伸破坏过程.通过模拟结果,对比、分析了两种单晶金属氧化物纳米线拉伸力学特性的差异.研究表明,1)ZnO纳米线的断裂机制为:表面微裂纹-微孔-微裂纹与微孔贯穿-断裂,而TiO_2纳米线的断裂机制为:局部屈服-颈缩-断裂;2)TiO_2纳米线的承载能力优于ZnO纳米线,而承受变形的能力劣于ZnO纳米线;3)温度较低的情况下,纳米线的抗拉性能较好;加载速度越高,纳米线的抗载性能越好,而抗变形能力越差.     

Analytical Approach to Space- and Time-Fractional Burgers Equations

A scheme is developed to study numerical solution of the space- and time-fractional Burgers equations under initial conditions by the homotopy analysis method. The fractional derivatives are considered in the Caputo sense. The solutions are given in the form of series with easily computable terms. Numerical solutions are calculated for the fractional Burgers equation to show the nature of solution as the fractional derivative parameter is changed.     

Effect of Zn Interstitials on Enhancing Ultraviolet Emission of ZnO Films Deposited by MOCVD

ZnO films are grown on Si （111） substrates by a metal organic chemical vapor deposition method. Samples with different stoichiometric composition of Zn and 0 are obtained by varying Ⅱ/Ⅵ molar ratio between 3 and 1/3 in precursors. The x-ray photoelectron spectroscopy and photoluminescenee results show that the ultraviolet emission enhances with the increasing Zn/O composition ratio of the samples. It is suggested that the supertfluous Zn atoms pile up at interstitial positions to form Zn interstitial defects. The radiated recombination of the coupling of free exeitons with donor Zn interstitial enhances the ultraviolet emission of the samples.     

Multi-Atom Entanglement Engineering in Distant Cavities via Resonant Interaction

We propose a scheme for the generation of entangled states for multiple atoms trapped in three distant cavities connected by two identical single-mode fibers. Compared with the previous schemes, the distinct advantages of the proposed scheme are： First, all the cavities in the proposed protocol can interact with each other freely, which is important in quantum communication and distributed quantum computation. Secondly, in the scheme, the atoms, cavities, and fiber mode are in resonance. Thus, the required interaction time is short, which is important in view of decoherence. In principle, the proposed scheme can be extended to generate n atoms entangled states.     

Differential and Integral Cross Sections for Electron Impact Excitation of Lithium

The differential and integral cross sections for electron impact excitation of lithium from the ground state 1s22s to excited states 1s22p, 1s23l （l=s, p, d） and 1s24l （l=s, p, d, f）at incident energies ranging from 5 eV to 25 eV are calculated by using a full relativistic distorted wave method. The target state wavefunctions are calculated by using the Grasp92 code. The continuum orbitals are computed in the distorted-wave approximation, in which the direct and exchange potentials among all the electrons are included. A part of the cross sections are compared with the available experimental data and with the previous theoretical values. It is found that, for the integral cross sections, the present calculations are in good agreement with the time-independent distorted wave method calculation, for differential cross sections, our results agree with the experimental data very well.