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171.
利用水热法在直流磁控溅射制备的掺铝氧化锌 (AZO) 种子层上制备了不同形貌和光学性能的掺银ZnO纳米棒, 并采用XRD、扫描电镜、透射谱、光发射谱和EDS谱详细研究了Ag离子与Zn离子的摩尔百分比 (RAg/Zn) 及AZO种子层对掺银ZnO纳米棒的结构和光学性质的影响. 随着RAg/Zn的增加, 掺银ZnO 纳米棒的微结构和光学性质的变化与银掺杂诱导的纳米棒的端面尺寸变化有关. 平均端面尺寸的变化归结于种子层颗粒大小和颗粒数密度不同导致掺入的Ag离子的相对比例不同. 溅射15 min的AZO种子层上生长的ZnO纳米棒由于缺陷增多导致在可见光区的发光峰明显强于溅射10 min 的AZO种子层上、相同RAg/Zn 条件下生长的ZnO纳米棒. Ag掺杂产生的点缺陷增多导致可见光区PL波包较宽. 纯ZnO纳米棒的微结构与种子层厚度导致的结晶度和颗粒大小有关.
关键词:
ZnO纳米棒
水热法
Ag掺杂
直流磁控溅射 相似文献
172.
Rodolfo Araya Abner H. Poza Frédéric Valentin 《Numerical Methods for Partial Differential Equations》2012,28(3):782-806
This work combines two complementary strategies for solving the steady incompressible Navier–Stokes model with a zeroth‐order term, namely, a stabilized finite element method and a mesh–refinement approach based on an error estimator. First, equal order interpolation spaces are adopted to approximate both the velocity and the pressure while stability is recovered within the stabilization approach. Also designed to handle advection dominated flows under zeroth‐order term influence, the stabilized method incorporates a new parameter with a threefold asymptotic behavior. Mesh adaptivity driven by a new hierarchical error estimator and built on the stabilized method is the second ingredient. The estimator construction process circumvents the saturation assumption by using an enhancing space strategy which is shown to be equivalent to the error. Several numerical tests validate the methodology. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011 相似文献
173.
A b-colouring of a graph is a colouring of its vertices such that every colour class contains a vertex that has a neighbour in all other classes. The b-chromatic number of a graph is the largest integer such that the graph has a -colouring with colours. We show here how to compute in polynomial time the -chromatic number of an outerplanar graph of girth at least . This generalizes the seminal result of Irving and Manlove on trees. 相似文献
174.
175.
Hydrophobic bimetallic catalysts of Pt-M on styrenedivinylbenzene were prepared, where M represents successively: Ir, Rh, Pd, Cu and Ag. The total metal loading was 0.5 wt% and the weight fractions of the metal M were: 0.0,0.05,0.1,0.25,0.5,0.75 and 1.0. For each sample, the catalytic activity for H/D exchange between hydrogen and water vapor was measured. In case of monometallic catalysts, no activity was detected for M = Cu and M = Ag, and the order of the activity values for the other metals was: Pt < Ir < Rh < Pd. For each bimetallic catalyst, the activity measurements indicated a clear interaction between the platinum and the second metal, thus the activity was significantly increased for M = Ir, increased for M = Rh, decreased for M = Pd, drastically decreased for M = Cu and M = Ag. 相似文献
176.
We prove the following Hartogs-Bochner type theorem: Let M be a connected C2 hypersurface of Pn(C) (n≥2) which divides Pn(C) in two connected open sets Ω1 and Ω2. Suppose that M has at most one open CR orbit. Then there exists i∈{1,2} such that C1 CR functions defined on M extends holomorphically to Ω
i
.
Supported by the TMR network. 相似文献
177.
In view of CdS growth is very impotent for technological importance especially solar applications; synthesis of this material remains a topic of great interest for researchers by means of an economically and technically viable method. In the present paper, Cd/CdS/n–Si/Au–Sb sandwich structure has been grown by Successive Ionic Layer Adsorption and Reaction (SILAR) technique. For investigating the structural properties, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) measurements have been performed and it has been seen that films exhibit polycrystalline behavior. The capacitance–voltage (C–V) and conductance/w-voltage (G/w–V) characteristics of Cd/CdS/n–Si/Au–Sb structure have been investigated by considering series resistance and interface states effects. These measurements have been done in the −4 V, 4 V voltage range and in the frequency range of 10 kHz–3 MHz at room temperature. It is seen that, the series resistance (Rs) and interface state density have been strongly depend on frequency. The barrier height, donor concentration, diffusion potential parameters have been determined from the linear C−2–V plot. The barrier height values are obtained between 0.495 and 0.796 eV and doping density values have been ranged from 1.455 × 1014 to 1.999 × 1014 cm−3respectively. The capacitance–frequency (C–f) and conductance/w-frequency (G/w–f) characteristics of Cd/CdS/n–Si/Au–Sb structures have been measured at the various biases 0.00–0.14 V at room temperature. The energy distribution of the interface states (Nss) and their relaxation time (τ) have been determined from the forward bias capacitance–frequency characteristics. The Nss and τ values have ranged from 2.01 × 1012 cm−2 eV−1and 9.68 × 10−4 s in (Ec-0.45) eV–2.86 × 1013 cm−2 eV−1 and 3.81 × 10−4 s in (Ec-0.75) eV, respectively. 相似文献
178.
I.?BaldomáEmail authorView authors OrcID profile O.?Castejón T.?M.?Seara 《Journal of Nonlinear Science》2018,28(4):1489-1549
In this paper, we prove the breakdown of the two-dimensional stable and unstable manifolds associated to two saddle-focus points which appear in the unfoldings of the Hopf-zero singularity. The method consists in obtaining an asymptotic formula for the difference between these manifolds which turns to be exponentially small respect to the unfolding parameter. The formula obtained is explicit but depends on the so-called Stokes constants, which arise in the study of the original vector field and which corresponds to the so-called inner equation in singular perturbation theory. 相似文献
179.
A. D.?RataEmail author T.?Hibma 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,43(2):195-200
We have grown VOx thin films on different substrates
in order to investigate the influence of epitaxial strain on the
transport properties. We found that the electric conductivity is
much larger for films grown under compressive strain on SrTiO3
substrates, as compared to bulk material and VOx films grown
under tensile strain on MgO substrates. A clear crossover from
metallic to semiconducting behavior is observed when increasing
the oxygen content x. Apparently, the application of strain
induces a Mott-Hubbard insulator-to-metal transition in
VOx<1. The VOx/SrTiO3 films show an unexpected large
positive magnetoresistance effect at low temperatures, which is
not found in the VOx films grown under tensile strain on MgO or
on a substrate with a similar lattice parameter. 相似文献
180.
The strong electromagnetic coupling between surface plasmon polariton modes on opposite interfaces of a finite thickness periodically nanostructured metal film has been studied. Surface polariton dispersion and associated electromagnetic field distributions have been analyzed. It was shown that at a frequency that corresponds to the crossing of film Bloch modes of different symmetries, the radiative losses of surface polaritons that are related to the polaritons' coupling to light during propagation on the structured surface are suppressed. 相似文献