Applied Mechanics and Materials Vol. 464

Abstract: Crystal structure and magnetic properties of hole-doped double perovskite compounds (Sr, Na)₂FeMoO₆ have been investigated by means of X-ray powder diffraction (XRD) and magnetic measurements. XRD pattern indicates that all the samples are of single phase and belong to the space group I4/m. The degree of cation ordering in the Na-doped Sr₂FeMoO₆ compounds shows a non-monotonic variation with the doping level, increasing from x=0 to x=0.03 and decreasing slightly with further increase of the doping. However, the Curie temperature of the compound decreases at low doping level and increases at high doping level.

Abstract: A simple and low-cost method based on a heat-treating of Ni (NO₃)₂/SiO₂ film has been developed for fabricating NiO nanorings. The as-prepared nanorings have an inner diameter of 150-250nm and an average wall thickness (namely wire diameter) of approximately 20 nm on the surface of SiO₂ matrix. Furthermore, a growth mechanism, namely bubble-bursting bubbles as templates was tentatively proposed for understanding the formation of the NiO nanorings.

Abstract: Direct laser forming directional solidification experiments were performed by using nickel-base superalloy as substrate and powder FGH96 as cladding material. The solidification microstructure of the cladding layer was investigated. Results showed that as-deposited microstructure was directionally solidified dendrites with the primary dendrite arm spacing of approximately 3μm and the secondary arm was small or even degenerated. According to the theory of columnar/equiaxed transition (CET) in front of the solid/liquid interface, it was found that in the single-path multi-layer cladding layers and multi-path multi-layer cladding layers, the microstructure with the same crystallographic orientation as the substrate was obtained by reasonably selecting the processing parameters. Composition segregation analysis showed a very uniform distribution of elements,and the segregation ratios were close to 1.

Abstract: Core-shell nanomaterials have been one of the most attracting research targets in the field of nanoscience and technology due to the multiple functionalities contributed from different components. In this paper, we report a facile solution synthetic method for the preparation of gold-nickel phosphide core-shell nanoparticles that have a near-spherical morphology and a size of ~20 nm. Transmission electron microscopy along with energy dispersive X-ray spectroscopy analyses reveals a core-shell structure consisting of gold core and nickel phosphide shell. The optical absorption data show that the surface plasmon resonance band of gold in the visible range is greatly decreased by coating nickel phosphide shell. The result of magnetic measurement reveals that the as-prepared core-shell nanoparticles basically exhibit paramagnetic characteristics. The obtained gold-nickel phosphide core-shell nanoparticles can be applied in application fields such as catalysis.

Abstract: The stress-strain behaviors were investigated by monotonic and cyclic stressing tests for high density aluminum foam at room temperature. The cyclic accumulations of deformation for the material were measured in varied loading levels. The effects of mean stress and stress ratio on the ratcheting strain were discussed. The experimental results show that tension response is different from the compressive response. There is obvious cyclic accumulations of deformation (i.e., ratcheting effect) under compression-compression cyclic loading even if the holistic stress-strain response is linear. And the ratcheting of aluminum foam greatly depends on mean stress and stress ratio in asymmetric stress cycling. The experimental rules and data are significant for constitutive description and numerical simulation of aluminum foam.

Abstract: This paper presents the results of optical characteristics of ITO thin film with different buffer layer thicknesses of SiO₂ and Nb₂O₅ for touch sensor application. SiO₂ and Nb₂O₅ buffer layers were deposited by using RF/DC magnetron sputtering equipment. Buffer layers were inserted between Glass and ITO layer. In order to compare with experimental results, Essential Macleod Program (EMP) was adopted. Based on EMP simulation, [Nb₂O₅/SiO₂/ITO] multi-layered thin film exhibited a high transmittance more than 85% in the visible region. The actual experimental results also showed transmittance more than 85% in the visible region, indicating the simulated results were well matched with experimental ones. The sheet resistance of ITO based film was about 300ohm/sq..

Abstract: Cellulaseassisted microwave extraction of polysaccharides from Elaeagnus angustifolia L. was researched. The four influential parameters, extraction temperature, pH value, microwave extraction power and microwave time, were optimized using the Box-Behnken design (BBD) with a quadratic regression model built by using response surface methodology (RSM). As results, the extraction conditions have significant effects on extraction yield of polysaccharide, a quadratic model was found to fit for EAP yield, and the optimal conditions was determined as following: extraction temperature of 38°C,pH value of 5.0,microwave power of 509W and irradiation time of 60 s. A maximum yield of 19.57± 0.02% for EAP was achieved in verification experiment.

Abstract: nanocomposite [(Co_91.5Zr_8.5)- or CZN films has been prepared by reactive co-sputter deposition method. Nitrogen content plays key role to tune soft magnetic properties. Experimental observation shows that, non-magnetic nitrogen content enhances magnetization and reduces coercivity. The nanostructure is composed of Co nanoclusters embedded in CoN/ZrN matrix, revealed by high resolution transmission electron microscope study. The d-spacing of single Co nanocluster was found to be ~0.22nm corresponding to (002) phase of Cobalt. X-ray diffraction result is in agreement with cubic (400) and (622) phase of CoZr. High electrical resistivity ρ_s~108μΩ-cm attained corresponding to 16% N₂ content films. Hysteresis loop squareness depends on film thickness and coercivity squareness (S^*)~0.84, obtained for ~250nm film thickness. A correlated composite nanostructure evolution is responsible for nitrogen induced magnetization and, suggests that film properties can tuned by controlling nitrogen content, in CoN/ZrN composite matrix.

Abstract: As PZT target are prepared from solid solution method. The perovskit phase evolution is investigated in this paper by DRX at different temperatures in order to show crystallization, morphology and structure of lead zirconate ceramics (PZT) target. Samples were deposited at room temperature on Aluminum (Al) and silicon (Si) substrates, and then heat-treated in a tabular furnace at 200 and 400°C during 30 min under atmospheric pressure. The films characterization were done glancing incidences X-ray diffraction (GIXRD) analysis with Fe K_α radiation (l=1.936Å ) at glancing angle of 1.5°for crystallographic characteristics; and Scanning Electron Microscopy (SEM-Zeiss ultra plus) in Ultra-High resolution imaging to observe surfaces morphology and cross-sections of thin films.We present in this paper a x-ray diffraction analysis, showing that as-deposited PZT films depend strongly on substrate nature, it presents an amorphous structure and nanocrystallizes in a pure perovskite phase PbZr_0.44Ti_0.56O₃ when it was deposited on Al substrate (followed by thermal treatement at 400°C).Ferroelectrics and piezoelectric properties are showed using Sawyer Tower circuit and impulsionel test respectively.

Abstract: The light scattering properties of the dent nanoparticles upon wafers is discussed in this paper. Taking the advantage of the Bobbert-Vlieger (BV) theorem, the scattering model between wafer and dent nanoparticles is established. The scattering process is analyzed and the scattering coefficients are derived by using of the vector spherical harmonic function. The differential scattering cross section (DSCS) of the dent nanoparticles upon the wafer is calculated which is compared with the extended Mie method proved the validity of the method and the influences of the dent position, dent scale and scattering angle on the DSCS are analyzed numerically in details. The result is shown that the effect of the dielectric is smaller than the metal. Therefore, the material of the defect and the shape can be extracted by calculate the DSCS, which provide strong theoretical foundation to the nondestructive detector engineer.