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991.
Simulation of spreading surfactant on a thin liquid film 总被引:1,自引:0,他引:1
The spreading of insoluble surfactant on a thin liquid film is modeled by a pair of nonlinear partial differential equations for the height of the free surface and the surfactant concentration. A numerical method is developed in which the leading edge of the surfactant is tracked. In the absence of higher order regularization the system becomes hyperbolic/degenerate-parabolic, introducing jumps in the height of the free surface and the surfactant concentration gradient. We compare numerical simulations to those of a hybrid Godunov method in which the height equation is treated as a scalar conservation law and a parabolic solver is used for the surfactant equation. We show how the tracking method applies to the full equations with realistic gravity and capillarity terms included, even though the disturbance in the height of the free surface extends beyond the support of the surfactant concentration. 相似文献
992.
A theoretical model is presented for the study of the magnetic properties and the coherent magnon transport via monatomic chains in ultrathin magnetic films. In particular, we studied a finite number of monatomic chains joining two slabs of ferromagnetic material. Each slab consists of five atomic layers of a cubic lattice with magnetically ordered spins coupled by the Heisenberg exchange. The system is supported on a non-magnetic substrate and otherwise considered free from magnetic interactions. The spin dynamics of the ultrathin film is studied by the matching method. The individual and the total magnon transmissions of the ultrathin ferromagnetic film, scattering coherently at the nanojunction zone, and the localized spin states in the boundary domain are calculated and analyzed. The interatomic magnetic exchange is varied on the boundary domain specifically for three cases of magnetic exchange to investigate the consequences of magnetic softening and hardening for the calculated properties. Numerical results show characteristic interference effects between the incident spinwaves and the localized spin states of the nanocontact. The calculated properties are presented for arbitrary incidence of the magnons on the boundary, for all accessible frequencies in the propagating bands, and for the interatomic magnetic exchange of the magnetic film. The localized magnon branches created by the nanocontact domain are observed in the Brillouin zone. 相似文献
993.
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995.
采用溶胶-凝胶法在玻璃基底上制备得到了高透光率,高导电性的掺铝氧化锌薄膜。研究了溶剂对薄膜晶体结构,薄膜厚度,表面形貌,光学性质和电学性质的影响,结果表明:在相同的制备条件下,薄膜的厚度随溶剂沸点的升高而降低;低沸点溶剂制备的薄膜由c轴择优取向的六角纤锌矿结构的晶体构成,且比较致密;所有薄膜可见光区的透光率在85%以上;乙二醇独甲醚为溶剂制备的薄膜电阻率最低,为3.0×1-0 4Ωm。 相似文献
996.
Bo Lu Yicheng Song Zhansheng Guo Junqian Zhang 《International Journal of Solids and Structures》2013,50(14-15):2495-2507
A semi-analytical method based on the cohesive model has been developed to investigate the progressive growth of interface delamination in an axisymmetric thin film electrode driven by diffusion-induced stresses under the assumption that the electrode remains elastic during the Li-ion diffusion process. The evolutions of the cohesive zone and debonding zone with respect to charging time have been predicted. The cohesive zone propagates in an accelerating manner and the debonding zone advances in a slowing down manner. The key parameters that control the interfacial stresses and delamination have been identified from the obtained governing equations. And according to the discussions on the key parameters, design insights into the geometry, charging velocity and material properties of the electrode have been provided. 相似文献
997.
Nanocrystalline La0.6Sr0.4Co0.2Fe0.8O3 − δ (LSCF) and La0.25Ba0.25Sr0.5Co0.2Fe0.8O3 − δ (LBSCF) with a high specific surface area (~ 40 m²/g) were synthesized by spray pyrolysis. The as prepared powder was characterized by X-ray diffraction, nitrogen adsorption, and high-resolution electron microscopy. Water-based dispersions of pure LSCF, LBSCF and mixtures containing gadolinium doped ceria (GDC) with agglomerate sizes of approx. 50 nm were prepared by application of ultrasonic energy. Spin coating was employed to prepare porous thin films. The thickness of the films (≤1 μm) was more than 10–20 times lower than conventional cathode layers. The interfacial polarization resistances of LBSCF cathodes are 19, 38, and 101 mΩ cm2 at 650, 600, and 550 °C, respectively. The high performance is attributed to the nanometer-sized grain dimensions, the nanoporosity, and the large specific surface area within the cathode layer. The novel approach of preparing nanoparticulate thin film cathodes suggests strong benefit for Micro Solid Oxide Fuel Cells operating below 500 °C. 相似文献
998.
M. Hartmanov M. Jergel C. Mansilla J.P. Holgado J. Zemek K. Jurek F. Kundracik 《Applied Surface Science》2009,255(22):9085-9091
Effect of the deposition temperature (200 and 500 °C) and composition of SmxCe1−xO2−x/2 (x = 0, 10.9–15.9 mol%) thin films prepared by electron beam physical vapor deposition (EB-PVD) and Ar+ ion beam assisted deposition (IBAD) combined with EB-PVD on structural characteristics and morphology/microstructure was investigated. The X-ray photoelectron spectroscopy (XPS) of the surface and electron probe microanalysis (EPMA) of the bulk of the film revealed the dominant occurrence of Ce4+ oxidation state, suggesting the presence of CeO2 phase, which was confirmed by X-ray diffraction (XRD). The Ce3+ oxidation states corresponding to Ce2O3 phase were in minority. The XRD and scanning electron microscopy (SEM) showed the polycrystalline columnar structure and a rooftop morphology of the surface. Effects of the preparation conditions (temperature, composition, IBAD) on the lattice parameter, grain size, perfection of the columnar growth and its impact on the surface morphology are analyzed and discussed. 相似文献
999.
Investigations were realized on the microstructural and morphological evolution of RF-sputtered vanadium pentoxide thin films during growth. V2O5 thin films at different stages of growth were studied by spectroscopic ellipsometry, X-ray diffraction, atomic force microscopy and scanning electron microscopy. Film grain orientation, roughness and density were found to have notable evolution during growth. Electrochemical tests in liquid and solid electrolyte state configuration showed non-linear relationship between discharge capacity and V2O5 film thickness (<1 μm), which could be attributed in parts to the observed morphological and microstructural changes during growth, mainly the existence of a gradient density through film thickness and the pronounced top surface roughness. 相似文献
1000.
Influence of Fe ions in characteristics and optical properties of mesoporous titanium oxide thin films 总被引:1,自引:0,他引:1
Yun Zhang Yue Shen Feng Gu Mingming Wu Yian Xie Jiancheng Zhang 《Applied Surface Science》2009,256(1):85-89
Fe-doped mesoporous titanium dioxide (M-TiO2-Fe) thin films have been prepared on indium tin oxide (ITO) glass substrates by sol–gel and spin coating methods. All films exhibited mesoporous structure with the pore size around 5–9 nm characterized by small angle X-ray diffraction (SAXRD) and further confirmed by high resolution transmission electron microscopy (HRTEM). Raman spectra illustrated that lower Fe-doping contributed to the formation of nanocrystalline of M-TiO2-Fe thin films. X-ray photoelectron spectroscopy (XPS) data indicated that the doped Fe ions exist in forms of Fe3+, which can play a role as e− or h+ traps and reduce e−/h+ pair recombination rate. Optical properties including refractive indices/n, energy gaps/Eg and Urbach energy width/E0 of the thin films were estimated and investigated by UV/vis transmittance spectra. The presence of Fe content extended the light absorption band and decreased the values of n, implying enhanced light response and performance on dye-sensitized solar cells (DSSC). The optimum Fe content in M-TiO2-Fe thin films is determined as 10 mol%, for its compatibility of well crystalline and well potential electron transfer performance. 相似文献