Modulation of Spin Distribution and Spin Transport by a Magnetic Field in a Quasi-One-Dimensional System with Spin--Orbit Coupling

The distributions of spin and currents modulated by magnetic field in a transverse parabolic confined two-dimensional electronic system with a Rashba spin--orbit coupling have been studied numerically. It is shown that the spin accumulation and the spin related current are generated by magnetic field if the spin--orbit coupling is presented. The distributions of charge and spin currents are antisymmetrical along the cross-section of confined system. A transversely applied electric field does not influence the characteristic behaviour of charge- and spin-dependent properties.     

四方相氧化锆纳米粉的低温合成与表征

氧化锆材料是近年来备受关注的陶瓷材料之一.它在许多不同的领域,诸如陶瓷颜料、工程陶瓷、宝石业、压电元件、离子交换器以及固体电解质方面等有着广泛的用途[1].其最常用的性质是其晶相转变时会有效改善陶瓷的脆性,因此在室温下保持其四方相是其中的关键.为此许多研究都侧重在其中加入各种添加剂,利用水热法、包裹法、形成共溶体等方法来阻止其晶格的转化[2-4].但研究也发现:在固定组成陶瓷基体中,ZrO2的相变温度随粉体颗粒直径的减小而降低,当颗粒足够小时能够提高材料强度的四方ZrO2可以保存到室温甚至室温以下.因此,减小ZrO2粉体粒度对于提高材料强度是非常有利的.本实验采用一种新的低温固相反应的方法制备氧化锆超细粉,从而使这种重要的陶瓷原料的制备有了新的思路.     

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The high speed CCD visible-light camera system has been installed to detect the dynamic characteristics of ELMs filaments on EAST tokamak. In order to convert the CCD video imaging coordinates into real space coordinates, the CCD system has calibrated using Tsai’s two-stage calibration technique. A raised spike in the grayscale profile, drawn by selecting the grayscale value of the image in the vertical direction of the ELMs filament in the CCD image, represents an ELMs filament structure whose positional coordinates are determined by the apex of the spike. The Sobel edge detection operator was used to examine the edge profile of the filament to obtain the width of the filament. By analyzing the characteristics of the filament width of the ELMs, it is found that the width of ELMs filaments continuously decreases outward from the outermost magnetic surface. This indicates that the filaments continue to dissipate energy and particles as they propagate outward. The width of filaments of Type-I ELMs is greater than that of Type-III ELMs.     

Mode equation and its solution for dielectric waveguide with parabolic cross-section

The mode equation for the dielectric waveguide with parabolic cross-section is derived using both the effective index method and WKB theory, and the expression of the mode propagation constant or effective index is solved directly from this mode equation, so that the mode-propagation properties of this kind of waveguide can be analysed conveniently with comparative accuracy.     

激光谐振腔内光学元件的热光效应

本文分析了多模激光束加热内腔元件所引起的温度场分布及热聚焦效应。计算得到的LiNbO₃寻常光和非常光的输入功率-输出功率曲线与Konvisar等人的实验结果符合,修正了他们计算的非常光曲线。在实验上,也观测了LiNbO₃的内腔热光滞后现象,并测量了内腔热光聚焦效应。 关键词：     

脉冲激光偏振方向对氮分子高次谐波的影响——基于含时密度泛函理论的模拟

采用含时密度泛函方法,结合赝势模型和电子交换相关作用的广义梯度近似,模拟了氮分子在超强飞秒激光脉冲作用下的高次谐波产生现象,并研究了激光脉冲偏振方向对氮分子高次谐波的影响.结果表明氮分子的高次谐波谱具有典型原子谐波谱的特征;谐波谱强度随着θ(激光偏振方向与分子轴向夹角)的增大而减小.这与J.Itatanl在Nature上报道的实验结果基本一致.     

单脉冲和多脉冲飞秒激光对单层光学薄膜的损伤

 利用掺钛的蓝宝石飞秒激光系统输出的单脉冲和多脉冲飞秒激光(中心波长800 nm，脉宽50 fs，靶面聚焦直径Ф 40 μm)，分别对BK7玻璃基底上厚约500 nm的单层HfO₂和单层ZrO₂薄膜进行辐照，得到了这两种薄膜在1-on-1和1 000-on-1测试方法下的激光损伤阈值。实验发现，两种方法下HfO₂单层膜的阈值均比ZrO₂单层膜的阈值高。从简化的Keldysh多光子离化理论出发，认为HfO₂薄膜材料的带比ZrO₂的宽是导致上述结果的主要原因。同时，同一种薄膜的多脉冲下的阈值比单脉冲下的低，原因是多脉冲下，飞秒激光对光学薄膜的损伤存在累积效应。     

排列形状及阵列数目对纳米导线阵列场发射性能的影响

为了进一步研究纳米导线阵列的排列形状以及阵列数目对其场发射行为的影响，利用镜像悬浮球模型对正方形以及六边形排列的纳米导线阵列的场发射行为进行计算与模拟，近似的得到纳米导线阵列的场发射增强因子满足如下的变化趋势：β=h/ρ(1/1+W)+1/2(1/1+W)²+3,其中h为纳米导线的高度，ρ为纳米导线的半径，W是以R为自变量的函数，R为纳米导线阵列的间距.结果显示纳米导线阵列的排列形状对其场发射性能的影响较小，而阵列间距则是影响场发射性能的关键因素：当R<R₀时，场发射增强因子随着阵列间距的减小而急剧减小；当R>R₀时，场发射增强因子基本不变，其中R₀为导线阵列场发射的最佳间距.进一步研究表明改变纳米导线阵列的数目基本不会改变阵列的场发射性能随间距的变化趋势，但是随着阵列数目的增加，R₀会有一定程度的减小，场发射增强因子也会降低. 关键词： 纳米导线 场发射 增强因子 阵列数目     

300kVA高温超导变压器电流引线漏热损耗的测量

电流引线是高温超导变压器的主要外部漏热来源,它的漏热量直接影响了超导变压器的经济性能,因此,引线的设计与漏热测量一直备受关注。文中构建了一个实验方案,运用量热法测量低压引线的漏热,并将试验结果与仿真预期值进行了对比和分析,从而验证了仿真设计的正确性。