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无 氧 条 件 下TiO2 薄 膜 界 面 光 催 化 反 应 的XPS 研 究  [PDF]
杨喜昆,胡显智,何 兵,楚国栋
分子催化 , 2009,
Abstract: 设 计 利 用 X 射 线 光 电 子 能 谱 仪 的 高 真 空 系 统 作 为 无 氧 条 件 下 光 催 化 反 应 和 分 析 的 场 所 , 研 究 真 空 无 氧 环 境 和 大 气 有 氧 环 境 中 紫 外 光 激 发 TiO2 薄 膜 表 面 的 光 催 化 反 应 , 并 对 无 氧 条 件 下 TiO2 薄 膜 降 解 亚 甲 基 蓝 进 行 初 步 探 索 . 结 果 表 明 , 在 大 气 有 氧 和 真 空 无 氧 条 件 下 TiO2 薄 膜 经 紫 外 光 照 后 , 表 面 的 化 学 组 成 和 化 学 状 态 均 发 生 了 变 化 ; 在 有 氧 环 境 中 TiO2 薄 膜 表 面 氧 含 量 增 加 , 而 在 无 氧 环 境 中 TiO2 薄 膜 表 面 氧 含 量 减 少 . TiO2 薄 膜 表 面 的 吸 附 氧 是 维 持 无 氧 条 件 下 光 催 化 反 应 的 重 要 原 因 , 增 加 薄 膜 表 面 吸 附 氧 的 含 量 能 提 高 TiO2 薄 膜 在 无 氧 环 境 中 的 催 化 活 性 . 此 外 , 无 氧 条 件 下 TiO2 薄 膜 降 解 亚 甲 基 蓝 光 催 化 反 应 过 程 中 , 亚 甲 基 蓝 分 子 只 是 脱 去 了 某 个 含 氮 的 基 团 , 生 成 了 中 间 产 物 , 而 并 没 有 完 全 降 解 .
Physics of ultracold Fermi gases revealed by spectroscopies  [PDF]
Paivi Torma
Physics , 2015,
Abstract: This article provides a brief review of how various spectroscopies have been used to investitage many-body quantum phenomena in the context of ultracold Fermi gases. In particular, work done with RF spectroscopy, Bragg spectroscopy and lattice modulation spectroscopy is considered. The theoretical basis of these spectroscopies, namely linear response theory in the many-body quantum physics context is briefly presented. Experiments related to the BCS-BEC crossover, imbalanced Fermi gases, polarons, possible pseudogap and Fermi liquid behaviour and measuring the contact are discussed. Remaining open problems and goals in the field are sketched from the perspective how spectroscopies could contribute.
Resonant scattering effect in spectroscopies of interacting atomic gases  [PDF]
M. J. Leskinen,J. Kajala,J. J. Kinnunen
Physics , 2009, DOI: 10.1088/1367-2630/12/8/083041
Abstract: We consider spectroscopies of strongly interacting atomic gases, and we propose a model for describing the coupling between quasiparticles and gapless phonon-like modes. Our model explains features in a wide range of different experiments in both fermionic and bosonic atom gases in various spectroscopic methods.
Nanoplasmonics: From biochemical sensors to surface enhanced spectroscopies  [cached]
P. M. Adam
Atti della Accademia Peloritana dei Pericolanti : Classe di Scienze Fisiche, Matematiche e Naturali , 2011, DOI: 10.1478/c1v89s1p015
Abstract: Plasmonics is a field connected to optics dealing with the properties and applications of surface plasmons which are modes of metal dielectric interfaces. Nanoplasmonics concerns the excitation, manipulation and detection of the surface plasmons at the nanometric scale. It has highly potential applications for ultrasensitive biochemical sensing. Surface enhanced spectroscopies are the ultimate sensor tools as they can reach single molecule sensitivity. We will present in this paper our results towards the realization of highly controllable and reproducible nanoplasmonics substrates.
Observation of a temperature dependent asymmetry in the domain structure of a Pd doped FeRh epilayer  [PDF]
C. J. Kinane,M. Loving,M. A. de Vries,R. Fan,T. R. Charlton,J. S. Claydon,D. A. Arena,F. Maccherozzi,S. S. Dhesi,D. Heiman,C. H. Marrows,L. H. Lewis,Sean Langridge
Physics , 2014, DOI: 10.1088/1367-2630/16/11/113073
Abstract: Using X-ray photoelectron emission microscopy we have observed the coexistence of ferromagnetic and antiferromagnetic phases in a (3 at.%)Pd-doped FeRh epilayer. By quantitatively analyzing the resultant images we observe that as the epilayer transforms there is a change in magnetic domain symmetry from predominantly twofold at lower temperatures through to an equally weighted combination of both four and twofold symmetries at higher temperature. It is postulated that the lowered symmetry Ising-like nematic phase resides at the near-surface of the epilayer. This behavior is different to that of undoped FeRh suggesting that the variation in symmetry is driven by the competing structural and electronic interactions in the nanoscale FeRh film coupled with the effect of the chemical doping disorder.
Investigation of dislocations in 8circ off-axis 4H-SiC epilayer

Miao Rui-Xi,Zhang Yu-Ming,Zhang Yi-Men,Tang Xiao-Yan,Gai Qing-Feng,

中国物理 B , 2010,
Abstract: This paper reports that the etching morphology of dislocations in 8circ off-axis 4H-SiC epilayer is observed by using a scanning electronic microscope. It is found that different types of dislocations correspond with different densities and basal plane dislcation (BPD) array and threading edge dislocation (TED) pileup group lie along some certain crystal directions in the epilayer. It is concluded that the elastic energy of threading screw dislocations (TSDs) is highest and TEDs is lowest among these dislocations, so the density of TSDs is lower than TEDs. The BPDs can convert to TEDs but TSDs can only propagate into the epilyer in spite of the higher elastic energy than TEDs. The reason of the form of BPDs array in epilayer is that the big step along the basal plane caused by face defects blocked the upstream atoms, and TEDs pileup group is that the dislocations slide is blocked by dislocation groups in epilayer.
Tetragonal Distortion of GaN Epilayer with Multiple Buffer Layers on Si (111) Studied by RBS/Channelling and HRXRD
Tetragonal Distortion of GaN Epilayer with Multiple Buffer Layers on Si (111) Studied by RBS/Channelling and HRXRD

DING Zhi-Bo,WANG Kun,ZHOU Sheng-Qiang,CHEN Tian-Xiang,YAO Shu-De,

中国物理快报 , 2007,
Abstract: Rutherford backscattering (RBS)/channelling and high resolution x-ray diffraction (HRXRD) have been used to characterize the tetragonal distortion of a GaN epilayer with four Alx Ga1-xN and single AIN buffer layers grown on a Si (111) substrate by metal-organic vapour phase epitaxy (MOVPE). The results show that a 1000nm GaN epilayer with a perfect crystal quality (Xmin = 1.54%) can be grown on the Si (111) substrate in virtue of multiple buffer layers. Using the RBS/channelling angular scan around an off-normal (1213) axis in the (1010) plane and the conventional HRXRD θ - 20 scans normal to GaN (0002) and (1122) planes at the 0° and 180° azimuth angles, the tetragonal distortion eT, which is caused by the elastic strain in the epilayer and different buffer layers, can be obtained respectively. The two experiments are testified at one result, the tetragonal distortion of GaN epilayer is nearly to a fully relaxed (eT = 0).
Influence of AlN buffer layer thickness on structural properties of GaN epilayer grown on Si (111) substrate with AlGaN interlayer

Wu Yu-Xin,Zhu Jian-Jun,Chen Gui-Feng,Zhang Shu-Ming,Jiang De-Sheng,Liu Zong-Shun,Zhao De-Gang,Wang Hui,Wang Yu-Tian,Yang Hui,

中国物理 B , 2010,
Abstract: We present the growth of GaN epilayer on Si (111) substrate with a single AlGaN interlayer sandwiched between the GaN epilayer and AlN buffer layer by using the metalorganic chemical vapour deposition. The influence of the AlN buffer layer thickness on structural properties of the GaN epilayer has been investigated by scanning electron microscopy, atomic force microscopy, optical microscopy and high-resolution x-ray diffraction. It is found that an AlN buffer layer with the appropriate thickness plays an important role in increasing compressive strain and improving crystal quality during the growth of AlGaN interlayer, which can introduce a more compressive strain into the subsequent grown GaN layer, and reduce the crack density and threading dislocation density in GaN film.
分子束外延Hg0.68Cd0.32Te薄膜光致发光和喇曼散射的研究  [PDF]
红外与毫米波学报 , 1998,
Abstract: 对利用MEB技术生长的Hg0.68Cd0.32Te薄膜进行了光致发光和喇曼光谱的研究,拟合薄膜光致发光谱得到的禁带宽度,与红外透射谱得到的薄膜带宽相近;其半宽仅为5meV,带尾能量小于1.3meV,显示了较高的薄膜质量。
Nuclear spin dynamics in a flourine-doped ZnSe epilayer  [PDF]
F. Heisterkamp,E. Kirstein,A. Greilich,E. A. Zhukov,T. Kazimierczuk,D. R. Yakovlev,A. Pawlis,M. Bayer
Physics , 2015,
Abstract: We study optically induced nuclear spin dynamics in a fluorine-doped ZnSe epilayer. The nuclear spin relaxation time $T_{1}$ of the $^{77}\text{Se}$ isotope under illumination is measured using an all-optical method in a magnetic field range from 10 to 130 mT and a lower limit for the spin relaxation time $T_{1}^{\text{dark}}$ without illumination is estimated. We combine optical methods with radio frequency techniques to measure Rabi oscillations, Ramsey fringes and the nuclear spin echo. The inhomogeneous nuclear spin dephasing time $T_{2}^{*}$ and the nuclear spin coherence time $T_{2}$ are measured using these techniques. While the $T_{1}$ time is on the order of several milliseconds, the $T_{2}$ time is on the order of several hundred microseconds. We find $T_{1}\gg T_{2}$ and conclude that the optically induced nuclear spin polarization can be described using the classical model of nuclear spin cooling.
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