Papers by Keyword: Surface

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Authors: Tai Long Gui, Si Da Jiang
Abstract: Using the radio frequency magnetron sputtering that directly bombardment A1N target under different sputtering-power and total pressure to deposit the A1N thin films. The crystal structure, composition, surface and refractive index of the thin films were studied by XRD, SEM, AFM and elliptical polarization instrument. The results show that the surface and refractive of the thin films strongly depends on the sputtering-power and total pressure,the good uniformity and smoothness is found at 225 W, Ar flow ratio 5.0 LAr/sccm, substrate temperature 100°Cand 1.2 Pa. All film thickness are from 60 to 80nm, and the highest N/Al mole ratio reach to 0.83.The crystal structure of the as-deposited thin-films is amorphous,then it transforms from blende structure to wurtzite structure as the rapid thermal annealing(RTA) temperature changes from 600 to 1200°C. The refractive index also increases with the RTA temperature it is increasing significantly from 800 to 1000°C. When the Annealing temperature at 1000°C, we get the best uniformity and smoothness of the surface of the film.
Authors: Sergey Dunaevsky, Evgeny Mikhailenko
Abstract: The results of "ab-initio" calculations of spin - polarized electronic structure, total energy and the local atomic magnetic moments of some manganite surfaces are presented. A slab consisting of one, three, five or, in some cases, seven layers of Mn-O atoms. is used to model the CaMnO3 (CMO), LaMnO3 (LMO) (001) surface. Total energies calculations of magnetic properties of manganites surfaces were performed using density-functional theory (DFT) and the pseudopotential method. We have found that on the surface layers without structural optimization manganese atomic magnetic moment is higher than in the bulk and “dead layers”, where all the local moments are zero, have not been found. All the above ultrathin films appeared ferromagnetic semimetals with almost complete polarization of DOS near the Fermi level.
Authors: Yue Ke, Catherine Moisson, S. Gaan, R.M. Feenstra, Robert P. Devaty, Wolfgang J. Choyke
Abstract: The effects of initial surface morphology on the early stages of porous SiC formation under highly biased photoelectrochemical etching conditions are discussed. We etched both Si-face and C-face polished n-type 6H SiC with different surface finishes prepared either by mechanical polishing or by chemical mechanical polishing at NOVASiC. For both Si-face and C-face porous SiC samples, a variety of surface and cross sectional porous morphologies, due to different surface finishes, are observed. The proposed explanation is based on the spatial distribution of holes at the interface of the SiC and electrolyte inside the semiconductor.
Authors: Zhi Qing Yuan, Bao Feng Song, Qi Long Liu, Hai Yun Jiang, Ji Ping Bin, Xian Wang, Ruo Mei Wu
Abstract: Inspired by the “lotus effect”, a porous superhydrophobic PS/PVC composites film comprised of many micro-spheres and nanofibers was obtained by a simple approach. These micro-spheres were interlinked with nano-fibers. The sizes of the micro-spheres were 0.6-3 µm, and the diameters of these nano-fibers were between 100-600 nm. The water contact angle and sliding angle on the superhydrophobic film were 155±1.8ºand 3º, respectively. When water flowed through the PS/PVC composites film for 2 h, no water bead was adhered on the superhydrophobic PS/PVC composites film, and the contact angle value was remained about 155°. Moreover, the contact angle were still higher than 150° when contacting with water with the temperatures ranging from 10°C to 60°C. The surface morphology of the PS/PVC composites film can be adjusted by changing the addition of PVC.
Authors: Jun Gang Huang, Chang You Li
Abstract: Parting surface design is the key to mold design. Taking mold design of a component as an example, this paper introduces the implementation of a parting surface design of complex multi-cavity mold supported by the surface technique of Pro/E software.
Authors: Ran Huang
Abstract: Since the first paper by Keddie et al. published on 1994 [21], the glass transition of polymer systems on surface/thin film has been an active research field and attracted many groups interests. Numerous works have been done, in both experimental and computation approaches, to investigate this subject. In this paper we reviewed the milestone findings in the last twenty years. Generally with only minor disagreements in the mechanism all the mainstream works are consistent in the conclusions that: 1) Geometric confinement in thin film or on surface reduces the glass transition temperature Tg comparing to the bulk behavior; 2) For supported film the substrate-film interaction is critical and its effect may surpass the geometry effects and rise increase on Tg; 3) Chain mobility and molecular weight are critical but the detailed phenomena vary with systems. Notwithstanding the achievement has been made, due to the controversy of glass transition itself and technology limitation on characterization on glass transitions on thin film, the research in this field is still a long-marching effort and breakthrough findings are expected for the development in materials science and engineering and feedback knowledge to understand the glass transition on the theoretical base.
Authors: Zhi Qing Yuan, Xi Hai Hao, Pu Shi, Yue Jun Liu, Guang Sheng Zeng
Abstract: A facile and inexpensive environmental-friendly method was developed to prepare a biomimetic superhydrophobic CuO surface with hierarchical micro- and nanostructures by the combination of a simple solid state reaction and a convenient dipping-coating method. The biomimetic CuO surface showed superhydrophobicity even for some corrosive liquids including salt solutions and acidic and basic solutions at a wide pH range from 2 to 13. Moreover, the superhydrophobic CuO surface showed high stability in ambient environment even exposed to ultraviolet light for 10 h.
Authors: A. Goodyear, A.P. Knights, N. Overton, Paul G. Coleman
Authors: Xin Wei Shi, Xing Rui Li, Ning Yao, Xin Chang Wang, Kai Lan Song, Shui Zhang
Abstract: TiN thin films were deposited by Arc Ion Plating(AIP) with or without Magnetic Filter(AIP or MFAIP) on silicon(Si) and high-speed steel(HSS) substrates,respectively.Scanning Electron Microscope(SEM),X-ray Diffraction(XRD),nanoindentation and microscratch tests were applied for microstructure and property investigation.SEM data showed that the AIP films are plagued with macro-particles(MPs),while the MFAIP films have no or less MPs.XRD showed that the MFAIP films have more obvious preferred orientation at (111) than the AIP films.Scratch Crack Propagation Resistance(CPRs) was introduced to evaluate the film adhesion properties in a scratch test.MFAIP films had higher adhesion.AIP films were susceptible to failure as the CPRs was lower.The MFAIP films had higher hardness than the AIP ones, due to the reason of less MPs in MFAIP films and more obvious preferred orientation.It was proposed that the MPs were effectively removed with the magnetic filter, so the properties of the MFAIP films were greatly improved.
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