Papers by Keyword: Multilayer

Abstract: The laminar cooling process has complex features, such as nonlinear, time-varying parameters, frequent changes of working conditions, and its difficult to achieve precise modeling and the traditional closed-loop control. A multi-layer virtual experiment platform with hybrid programming of configuration is proposed in the paper. Not only does this platform keep the environment similar to the industrial field, but also saves money on purchasing the hardware system.

Abstract: Thermal load oozing out through the door is the main aspect of the temperature zone heat loss of continuous diffusion furnace. In this paper, multi-layer gas curtain is designed to seal the furnace door in order to reduce heat loss and ensure furnace temperature to meet requirements in regulation. The unsteady flow is presented to better reflect complex time-varying velocity and temperature of curtain gas. Flow and temperature field of continuous diffusion door with multi-layer air curtain are numerically analyzed by Renault model and experimentally tested. And the influence parameters are tuned and optimized based on the theoretic numerical analysis and experiment results.

Abstract: Segmentation of motion in an image sequence is one of the most challenging problems in image processing, while at the same time one that finds numerous applications. In this paper, we propose a robust multi-layer background subtraction technique which takes advantages of local texture features represented by local binary patterns (LBP) and photometric invariant color measurements in RGB color space. Due to the use of a simple layer-based strategy, the approach can model moving background pixels with quasiperiodic flickering as well as background scenes which may vary over time due to the addition and removal of long-time stationary objects. The use of a cross-bilateral filter allows to implicitly smooth detection results over regions of similar intensity and preserve object boundaries.

Abstract: In order to improve a biocompatibility of a NiTi shape memory alloys used as a long-term implant, surface was covered by protective multi-layers coating. First, alloy was passivated in autoclave, and then hydroxyapatite was deposited using electrophoresis at room temperature. In result of that multi-layer was formed on the top of the surface consisted of titanium oxide and hydroxyapatite. Phase identification done with use of grazing incidence beam X-ray diffraction proved sequence of obtained coatings. Applied procedure for multi-layer deposition allowed avoiding of the B2 parent phase decomposition. Moreover, the martensitic transformation occurs in two-steps.

Abstract: A multilayer TiO₂ film featured with gradual scattering structure was developed and used as photoelectrode for dye-sensitized solar cells. This structure of film consists of P25 nanoparticles and TiO₂ aggregate which was synthesized by micro-emulsion method as scattering centers The scattering centers were deposited by gradually increasing the amount from the film’s bottom to its top. The special films were used for the studies on the photovoltaic performance of N719 and Zn-3, and their photoelectric conversion efficiencies were 7.34% and 4.04%, respectively. Furthermore, more improvement of the conversion efficiency is realized for Zn-3 than for N719 by using our newly developed multilayer films as photoelectrode compared with ordinary photoelectrode.

Abstract: In recent years there have been many studies attempting to increase the mechanical properties and reliability of structural ceramic materials; the forming methods used for this purpose are based on multi-layered materials to induce residual stress between interface layers. In this work were made monolithic and multi-layered materials manufactured by casting in plaster of Paris molds using zircon and alumina as raw materials, mechanical and microstructure characterizations were compared, founding that, indeed, the laminar designs can substantially improve the mechanical properties of manufactured materials by the compressive stress between the interface layers.

Abstract: In order to synthesize the multi-layer radar absorbing materials (RAM) with a thin thickness and wide bandwidth, accelerating genetic algorithm (GA) with constraints and elitist strategy is employed to design the multi-layer RAM satisfied by a special value of reflection loss to electromagnetic wave. Given predefined available materials with frequency-dependent permittivity and permeability, the GA technique determines the optimal material choice for each layer and its thickness. The algorithm was successfully applied to the synthesis of double-layer to four-layers RAM coatings in the frequency range of 2-18GHz,and the optimization results was evaluated.

Abstract: A brief review on various possibilities of studying internal interfaces in metals by various methods of Mössbauer (nuclear gamma-resonance) spectroscopy is presented. Specific features of investigations of different interfaces in various materials are considered, such as equilibrium boundaries of recrystallization origin in coarse-grained materials, non-equilibrium boundaries in submicro-and nanocrystalline materials and interlayer boundaries in multilayered structures.

Abstract: The CrN and Cr/CrN multilayer coatings with different modulation ratios were deposited onto stainless steel and cemented carbide substrates by arc ion plating technology. The phase composition, surface and cross-sectional morphology were analyzed by using X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscope (SEM). The micro Vickers was used to test the hardness. The results indicated that the coatings were mainly composed of Cr, CrN and Cr2N phase. No columnar grain growth was observed in Cr/CrN multilayer coatings, and the crystalline orientation of the Cr/CrN multilayer was different from CrN film. There exists an optimal modulation ratio of 10:10 to the coating deposition, under which the surface was compact and smooth with a relatively lower roughness. The coatings hardness increased with decreasing modulation ratio and the hardness of CrN+Cr2N was lower than that of single CrN phase.

Abstract: In this paper, the multi-layered gradient materials consisting of polarized polymers and small molecules were prepared and the damping properties were studied by DMA. The predicted and experimental results showed that, it was possible to obtain damping material with broad efficient damping range by two-layered hybrid materials, the value in the middle of two peaks could be improved by increasing the number of layers of the multi-layered hybrids and there was a higher minimum value. On the other hand, with increased number of the layers of the multi-layered hybrid materials, the temperature dependence of could be improved. For five-layered gradient materials, it was almost rectangular transition range with values for the area under the linear curve. Thus, it would be feasible in theory and experiment to broaden the efficient damping range by multi-layered gradient materials based on organic hybrids, which provided a new approach and solid basis for developing high performance damping materials with a broad and high damping range.