直流磁控溅射厚度对Cu(Inx,Ga1-x)Se2背接触Mo薄膜性能的影响

采用直流磁控溅射工艺, 在一定条件下通过控制溅射时间, 在钠钙玻璃上制备了不同厚度的用于Cu(In_x, Ga_1-x)Se₂薄膜太阳电池背接触材料的Mo薄膜, 并利用X射线衍射 (XRD)、场发射扫描电子显微镜 (SEM)、四探针测试仪、台阶仪研究了厚度对溅射时间、薄膜微结构、电学性能及力学性能的交互影响. Mo薄膜的厚度与溅射时间呈线性递增关系; 随厚度的增大, Mo薄膜 (110) 和 (211) 面峰强均逐渐增大, 择优生长从(110)方向逐渐向 (211)方向转变, 方块电阻值只随 (110) 方向上的生长而急剧减小直到一特定值约2 Ω/⇑, 电导率随薄膜的 (110) 择优取向程度的降低而线性减小直到一特定值约0.96×10^-4 Ω·cm; Mo薄膜内部是一种多孔的长形簇状颗粒和颗粒间隙交织的结构, 并处于拉应力态, 其内部应变随薄膜厚度的增大而减小. 关键词： Mo薄膜 CIGS背接触 厚度 微结构     

偏分复用系统中偏振模色散补偿与偏分解复用一体化方案

本文建立了偏分复用系统中偏振模色散与信号偏振态变化引起信道串扰的数学模型, 分析了偏振模色散对偏分复用信道射频功率的影响, 并提出了适用于偏分复用系统的光域偏振模色散补偿与偏分解复用同时进行的方案: 用信道的射频功率作为反馈控制信号, 监测链路中偏振模色散和偏振态变化引起的信道串扰的大小, 用改进的粒子群优化算法对偏振控制器进行自适应控制, 同时完成偏振模色散补偿与偏分解复用. 在112 Gb/s偏分复用-差分正交相移键控(PDM-DQPSK)传输系统中仿真验证了该方案的有效性. 结果表明该方案可以使112 Gb/s-PDM-DQPSK传输系统完成自适应偏分解复用的同时, 在1 dB的光信噪比代价下, 使系统对偏振模色散的容忍度提高20 ps. 关键词： 偏分复用系统 信道串扰 偏振模色散 偏分解复用     

熔体初始温度对液态金属Ni凝固过程中微观结构演变影响的模拟研究

采用量子 Sutton-Chen多体势, 对熔体初始温度热历史条件对液态金属Ni快速凝固过程中微观结构演变的影响进行了分子动力学模拟研究. 采用双体分布函数g(r)曲线、键型指数法、原子团类型指数法和三维可视化等分析方法对凝固过程中微观结构的演变进行了分析. 结果表明: 熔体初始温度对凝固微结构有显著影响, 但在液态和过冷态时的影响并不明显, 只有在结晶转变温度T_c附近才开始充分显现出来. 体系在1×10¹² K/s的冷速下, 最终均形成以1421和1422键型或面心立方(12 0 0 0 12 0)与六角密集(12 0 0 0 6 6) 基本原子团为主的晶态结构. 末态时, 不同初始温度体系中的主要键型和团簇的数目有很大的变化范围, 且与熔体初始温度的高低呈非线性变化关系. 然而, 体系能量随初始温度呈线性变化关系, 初始温度越高, 末态能量越低, 其晶化程度越高. 通过三维可视化分析进一步发现, 在初始温度较高的体系中, 同类团簇结构的原子出现明显的分层聚集现象, 随着初始温度的下降, 这种分层现象将被弥散开去. 可视化分析将更有助于对凝固过程中微观结构演变进行更为深入的研究. 关键词： 液态金属Ni 熔体初始温度 微观结构 分子动力学模拟     

亚微秒脉冲表面介质阻挡放电等离子体诱导连续漩涡的研究

使用粒子激光图像测速技术对亚微秒脉冲激励表面介质阻挡放电激励器连续产生诱导漩涡进行了实验研究, 给出了包含脉冲重复频率和漩涡频率的双频率激励模式的具体形式. 实验过程中出现了原发型与继发型两类示踪粒子空白区, 前者由放电释热的微爆炸作用造成, 使得诱导流动远离壁面, 能够减小壁面摩擦阻力的作用; 以暴露电极左侧继发型空白区被完全吹除作为重复启动激励的临界点. 为提高控制效果应采用尽可能高的脉冲重复频率, 漩涡时间内脉冲数量应大于10, 最大诱导速度随脉冲数量增大而增大, 但动量传递效率降低. 使用亚微秒脉冲激励具备释热、体积力两种作用机理. 关键词： 双频率亚微秒脉冲 表面介质阻挡放电 连续漩涡     

Theoretical study of stabilities,electronic, and catalytic performance of supported platinum on modified graphene

The geometry, electronic structure, and catalytic properties for CO oxidation of Pt atom supported on pri-graphene (PG), Haeckelite (H), and Stone–Wales-defect-graphene are investigated by density functional theory (DFT) calculations. In contrast to a Pt atom on PG, defective graphene, especially the Haeckelite, strongly stabilises the Pt atom and makes it more positive and thus the CO poisoning. At the same time the catalytic activities are as high as the pristine one. Langmuir–Hinshelwood mechanisms are favoured as the starting state and are followed by the Eley–Rideal reaction. The results indicate the benefit of Haeckelite as a substrate for the Pt atom and validate the reactivity of catalysts on the atomic scale with low cost and high activity.     

Semipolar (11\bar 2\bar 2) ZnO thin films grown on LaAlO3‐buffered LSAT (112) single crystals by pulsed laser deposition

Semipolar (11\bar 2 \bar 2) ZnO was successfully grown on (112) LaAlO₃/(LaAlO₃)_0.29(Sr₂AlTaO₆)_0.35 substrate by pulsed laser deposition. The epitaxial relationship is [11\bar 23]_{\rm ZnO} // [11\bar 1]_{\rm LAO/LSAT} with the polar axis of [000\bar 1]_{\rm ZnO} pointing to the surface. For ZnO films with thickness of 1.6 μm, the threading dislocation density is ～1 × 10⁹ cm^–2, and the density of basal stacking faults is below 1 × 10⁴ cm^–1. The (11\bar 2 \bar 2) ZnO exhibits strong D⁰X emissions with a FWHM of 9 meV and very few green–yellow emissions in the low‐temperature (10 K) and room‐temperature photoluminescence spectra, respectively.

     

周期性纳米洞内边缘氧饱和石墨烯纳米带的电子特性

利用基于密度泛函理论的第一性原理方法,研究了内边缘氧饱和的周期性凿洞石墨烯纳米带（G NR）的电子特性. 研究结果表明：对于凿洞锯齿形石墨烯纳米带（ZGNRs）,在非磁性态时不仅始终为金属,且金属性明显增强;反铁磁态（AFM）时为半导体的ZGNR,凿洞后可能成为金属;但铁磁态（FM）为金属的ZGNR,凿洞后一般变为半导体或半金属. 而对于凿洞的扶手椅形石墨烯（AGNRs）,其带隙会明显增加. 深入分析发现：这是由于氧原子对石墨烯纳米带边的电子特性有重要的影响,以及颈次级纳米带（NSNR）及边缘次级纳米带（ESNR）的不同宽度及边缘形状（锯齿或扶手椅形）能呈现出不同的量子限域效应. 这些研究对于发展纳米电子器件有重要的意义. 关键词： 石墨烯纳米带 纳米洞 内边缘氧饱和 电子特性     

Interaction Between Neuroglobin and Caffeine by Multispectroscopic Methods

The interaction between neuroglobin (Ngb) and caffeine was studied by spectroscopy. UV-Vis spectra revealed that caffeine did not influence the native hexa-coordinated heme structure of neuroglobin. Fluorescence spectra indicated that caffeine could quench the intrinsic fluorescence of neuroglobin through static quenching mechanisms. The calculated thermodynamic parameters showed that the electrostatic force was the main intermolecular force in the reaction. Results also indicated that the microenvironmental changes of tryptophan and tyrosine residues within neuroglobin are inapparent. Furthermore, the circular dichroism (CD) spectra implied that caffeine could induce the formation of α-helix structure of neuroglobin.     

Lie symmetries and nonlocally related systems of the continuous and discrete dispersive long waves system by geometric approach

By using the extended Harrison and Estabrook's differential forms approach, in this paper, we investigate the Lie symmetries of the continuous and discrete dispersive long waves system, respectively. Based on this method, two closed ideals written in terms of a set of differential forms are constructed for the dispersive long waves systems. Furthermore, some invariant solutions are presented for such systems. By a direct computation, it is shown that the discrete dispersive long waves system admits a Kac-Moody-Virasoro type and a Virasoro-like type Lie algebra, respectively. Finally, we present an interesting relationship between the continuous case and a modified dispersive long waves system, which can be used to find nonlocal properties for such systems with each other.