共查询到20条相似文献,搜索用时 15 毫秒
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Eric Sultan Arezki Boudaoud Martine Ben Amar 《Journal of Engineering Mathematics》2004,50(2-3):209-222
The stability of evaporating very thin films of a polar liquid is investigated. The microscopic interaction with the substrate
and capillarity are taken into account in a lubrication equation. The stability of a flat interface is studied when evaporation
is limited by the diffusion of the vapour in the gas phase. The evaporation rate is computed and evaporation is shown to be
stabilizing. A stability phase diagram is obtained. A weakly nonlinear analysis leads to a film-thickness amplitude equation
that is non local in space. Physical consequences of the results are eventually discussed. 相似文献
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AbstractIn this work, the thermal stability and the oxidation and tribological behavior of nanoporous a-BC:H films are studied and compared with those in conventional diamond-like carbon (DLC) films. a-BC:H films were deposited by pulsed plasma chemical vapor deposition using B(CH3)3 gas as the boron source. A DLC interlayer was used to prevent the a-BC:H film delamination produced by oxidation. Thermal stability of a-BC:H films, with no delamination signs after annealing at 500 °C for 1 h, is better than that of the DLC films, which completely disappeared under the same conditions. Tribological test results indicate that the a-BC:H films, even with lower nanoindentation hardness than the DLC films, show an excellent boundary oil lubricated behavior, with lower friction coefficient and reduce the wear rate of counter materials than those on the DLC film. The good materials properties such as low modulus of elasticity and the formation of micropores from the original nanopores during boundary regimes explain this better performance. Results show that porous a-BC:H films may be an alternative for segmented DLC films in applications where severe tribological conditions and complex shapes exist, so surface patterning is unfeasible. 相似文献
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在等效粘度模型的基础上,考虑温度对润滑剂粘度的影响,建立了粘-温修正的等效粘度分析计算模型,并运用该模型进行薄膜润滑条件下的轴承性能分析计算,得到了不同参数下轴承性能的变化规律。 相似文献
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J. Marciak-Kozłowska Z. Mucha M. Kozłowski 《International Journal of Thermophysics》1995,16(6):1489-1497
In this paper it has been shown that, with the advent of lasers with a very short pulse duration, the effect of thermal wave propagation becomes important. To consider this effect, hyperbolic heat conduction in thin gold films was studied. It was shown that for heat fluxes of the order 108 W·cm–2, a thermal wave is generated in thin gold films. The consideration of the hyperbolicity of heat transfer enables one to describe the temperature profile with one value of fluence. 相似文献
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Nanocrystalline ZnS thin films are prepared on glass and quartz substrates by sulfurizing ZnO thin films in the H2S-containing mixture at 500 °C. These films are investigated by X-ray diffraction, scanning electron morphology, optical transmittance and photoluminescence spectra. The results show that the ZnS thin films have the hexagonal structure with a c-axis preferred orientation. Also, these nanostructure ZnS thin films with the grain size of ∼50 nm along the c-axis, exhibit the optical transparency as high as ∼80% in the visible region. It is found that sulfur replacement of oxygen sites in crystal lattices and recrystallization can take place during sulfidation, resulting in an evident increase of the grain size for the sulfurized films. Under the optimum sulfidation time of 2 h, the resultant ZnS thin films have a high crystallinity, low defect concentration and good optical properties with the band gap of 3.66 eV. 相似文献
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Ferydon Babaei 《Journal of Modern Optics》2013,60(11):886-890
The generalized ellipsometry formalism was used for a right-handed ambichiral sculptured thin film. The amplitude ratios and phase differences were calculated using an experimental dielectric function for bulk titania. The results showed that the occurrence of the circular Bragg regimes can be adduced from ellipsometry spectra. 相似文献
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A theory is formulated to describe the dynamics of a thin film flowing down an inclined plane laden with insoluble surfactant,
present in dilute concentrations. Use of lubrication theory yields a coupled pair of partial differential equations for the
film height and surfactant monolayer concentration. The contact line singularity is relieved by assuming the presence of a
thin precursor layer ahead of the advancing film. Base flow solutions for a flow of constant flux are examined over various
inclination angle, precursor-layer thickness, Peclet number, and capillary parameter ranges. Application of a transient growth
analysis highlights the presence of an instability and the vulnerability of the flow to transverse disturbances of intermediate
wavenumber. Our results reveal that several key features of the much-studied uncontaminated film flow, including stability,
are modified qualitatively by the inclusion of surfactant. 相似文献
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Ferydon Babaei 《Journal of Modern Optics》2013,60(16):1370-1375
The optical rotation and selective transmission spectra of ambichiral sculptured thin films were calculated using the transfer matrix method. The results of optical modeling showed that at lower angular rotations the optical characteristics of ambichiral sculptured thin films are the same as chiral sculptured thin films. At higher angular rotations, two circular Bragg regimes appear. An ambichiral sculptured thin film in one regime reflects left circularly polarized (LCP) light and in a second regime reflects right circularly polarized (RCP) light. The optical properties of ambichiral sculptured thin films with twist and layer defects as spectral holes are also reported. 相似文献
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Fibrous Parylene-C films with tilted columnar morphology were deposited with a physicochemical version of the oblique-angle deposition (OAD) technique. Advancing contact angles increased from 103.9° (smooth hydrophobic surface) to 168.5° (rough superhydrophobic surface) as the thickness of the film increased from ∼ 100 nm to ∼ 60 μm, reflecting changes in the morphology of the top surface. Treatment with oxygen plasma can render these fibrous films completely water wettable. These techniques allow tailoring of surface wettability to meet the demands of specific biomedical applications. 相似文献
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J.J. Vlassak 《International Journal of Fracture》2003,119(4):299-323
Solutions are presented for the elastic plane-strain problem of a crack in a coating on a compliant substrate of finite thickness. Analysis of the problem shows that substrate thickness has a significant effect on the steady-state energy release rate for channel cracks. This is so over a wide range of elastic mismatch between film and substrate, but is especially important if the substrate is more compliant than the film. Relaxation of the film stress due to elastic deformation of the substrate also plays an important role. If the substrate is clamped around the edge, as would be the case for a coated membrane, the stress in the coating cannot relax and the energy release rate for channel cracking increases significantly with decreasing substrate thickness. If the film stress is allowed to relax, however, the driving force for cracking is reduced as the substrate thickness decreases. The results from this study are used to evaluate the change in curvature of a film/substrate assembly due to channel cracking, a quantity that is of interest for the experimental determination of stresses in thin films. An expression for the elastic extension of the substrate due to channel cracking is derived making it possible to evaluate the effect of cracking on the mechanical behavior of bilayer membranes. It is expected that the present study may lead to the development of new experimental techniques for measuring the fracture toughness of thin coatings. 相似文献
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ZnO薄膜应用的最新研究进展 总被引:26,自引:3,他引:26
ZnO是一种新型的Ⅱ-Ⅵ族半导体材料。详细介绍了ZnO薄膜在太阳能电池、表面声波器件、气敏元件、压敏器件等领域的应用以及在紫外探测器、LED、LD等潜在应用领域研究开发的最新进展。 相似文献