一种脉冲强电流条件下导线电阻测量方法

在超强激光辐照电容线圈靶产生强磁场实验中,在约50 ps时,线圈电流达到20 kA以上。通过该实验结果与磁场产生理论模型对比,可得出该导线电阻值比常温直流电阻高出3个量级。对导线材料电阻率与趋肤效应的分析结果表明,该电阻值在量级上是合理的。获得超快脉冲强电流条件下的导线电阻值,有助于更深入理解线圈靶产生强磁场过程。     

钴掺杂MoSe2共生长中氢气的作用分析及磁电特性研究

采用原位共生长化学气相沉积法,以Co3O4、MoO3、Se粉末为前驱物,710℃下在SiO2衬底上生长掺钴MoSe2纳米薄片,分析讨论氢气含量对其生长及调节机理的影响.表面形貌分析表明,氢气的引入促进了成核所需的氧硒金属化合物以及横向生长中需要的CoMoSe化合物分子的生成;AFM(Atomic Force Microscope)结果表明氢气有利于生长单层二维超薄掺钴MoSe2.随着Co3O4前驱物用量的增加,样品的拉曼和PL(Photoluminescence)谱图分别表现出红移和蓝移现象,带隙实现从1.52—1.57 eV的调制.XPS(X-ray photoelectron spectroscopy)结果分析得到Co的元素组分比为4.4%.通过SQUID-VSM(Superconducting QUantum Interference Device)和器件电学测试分析了样品的磁电特性,结果表明Co掺入后MoSe2由抗磁性变为软磁性;背栅FETs器件的阈值电压比纯MoSe2向正向偏移5 V且关态电流更低;为超薄二维材料磁电特性研究及应用拓展提供了基础探索.     

Interaction of localized electronic states with the conduction band: band anticrossing in II-VI semiconductor ternaries

We report a strongly nonlinear pressure dependence of the band gaps and large downward shifts of the conduction band edges as functions of composition in ZnS xTe (1-x) and ZnSe (y)Te (1-y) alloys. The dependencies are explained by an interaction between localized A1 symmetry states of S or Se atoms and the extended states of the ZnTe matrix. These results, combined with previous studies of III-N-V materials define a new, broad class of semiconductor alloys in which the introduction of highly electronegative atoms leads to dramatic modifications of the conduction band structure. The modifications are well described by the recently introduced band anticrossing model.     

基于云环境的分布式软件接口自动化测试

软件测试是保证软件质量,提供可靠服务的重要技术手段。目前基于Web Service的分布式软件越来越多,其测试技术手段也越来越受到关注。Web Service的分布性和多样性使手工测试变得非常低效,因而需要不断提高Web Service测试的自动化程度。另外,云计算因其计算成本低、可伸缩性强的特点为自动化测试提供了新的支持环境。本文结合Web Service的测试需求,首次提出了基于云环境的Web Service接口自动化测试的技术框架,分析了框架内原子Web Service、组合Web Service测试的关键技术,并研发了基于CloudStack云平台的自动化测试的原型系统。实验结果表明,本文所提出的基于云平台的WebService自动化测试方案可行且提高了测试效率。     

Perforated nanocap array: Facile fabrication process and efficient surface enhanced Raman scattering with fluorescence suppression

Recently, individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively. However, little attention has been paid to the approach to fabricating ordered reduced-symmetry metal nanostructure arrays. In this paper, a novel perforated silver nanocap array with high surface-enhanced Raman scattering (SERS) activity and fluorescence suppression is reported. The array is fabricated by electron beam evaporating Ag onto the perforated barrier layer side of a hard anodization (HA) anodic aluminum oxide (AAO) template. The morphology and optical property of the perforated silver nanocap array are characterized by an atomic force microscope (AFM), a scanning electron microscope (SEM), and absorption spectra. The results of SERS measurements reveal that the perforated silver nanocap array offers high SERS activity and fluorescence suppression compared with an imperforated silver nanocap array.     

Design of a sector bowtie nano-rectenna for optical power and infrared detection

We designed a sector bowtie nanoantenna integrated with a rectifier (Au−TiO_x−Ti diode) for collecting infrared energy. The optical performance of the metallic bowtie nanoantenna was numerically investigated at infrared frequencies (5−30 μm) using three-dimensional frequency-domain electromagnetic field calculation software based on the finite element method. The simulation results indicate that the resonance wavelength and local field enhancement are greatly affected by the shape and size of the bowtie nanoantenna, as well as the relative permittivity and conductivity of the dielectric layer. The output current of the rectified nano-rectenna is substantially at nanoampere magnitude with an electric field intensity of 1 V/m. Moreover, the power conversion efficiency for devices with three different substrates illustrates that a substrate with a larger refractive index yields a higher efficiency and longer infrared response wavelength. Consequently, the optimized structure can provide theoretical support for the design of novel optical rectennas and fabrication of optoelectronic devices.     

General Formalism for Setting Up Unitary Transform Operators from Classical Transforms via IWOP Technique

We present a general formalism for setting up unitary transform operators from classical transforms via the technique of integration within an ordered product of operators, their normally ordered form can be obtained too.     

对等网络应用中的网络统计特征分析

本文基于实测数据抽象出用户网络与资源网络,探讨了对等网络中用户、资源及其内部的相互作用关系,发掘并分析了其内在的网络统计特征. 分析结果表明,用户节点度值及权值呈分段分布,体现了其各异的活跃性;网络资源的流行度差异明显,度值和权值近似呈幂律分布. 用户网络与资源网络存在分簇结构,少数簇中含大量节点,多数簇所含节点数量较少. 用户网络中,同簇内的用户有着相似的兴趣趋向,不同簇用户间兴趣趋向存在着差异,资源网络各簇中不同类别的资源间呈现出明显的关联性.