Advanced Materials Research Vols. 706-708

Abstract: ZnO with ZnO/ZnMgO super lattice buffer layers grown by molecular beam epitaxy on Si (100) substrates at room temperature were studied by reversing the epitaxial sequence of ZnO or ZnMgO in the super lattice buffer layers, tuning the oxygen power and the vacuum pressure. The crystal quality was improved by supper lattice buffer layers started with ZnO, using higher oxygen power, and proper vacuum pressure in the growth chamber.

Abstract: A novel aromatic Schiff base ligand has been designed and its interfacial phase behavior as well as the in situ coordination with Cu(II) ion was investigated. A series of measurement methods, such as surface pressure-area isotherms and atomic force microscopy measurement, have been used to characterize the deposited monolayer and multilayer films. It has been found that both the ligand and the corresponding complex formed stable monolayer or multilayer films at the air/water interface, which could be subsequently transferred onto solid substrates to construct Langmuir-Blodgett films. It was interesting to note that there existed a novel phase transition when the ligand was spread on pure water surface. During this phase transition, the two dimensional flat film changed into a three dimensional fiber-like nano-architectures. However, upon coordinating with Cu(II) ions, only flat films were obtained. Such distinct difference was suggested to be mainly due to the change of molecular conformation and/or the hydrophobicity in the process of supramolecular assembly at the air/water interface.

Abstract: Depositing TiN Film on the surface of 4Cr5MoSiV1 with multi-arc ion plating technology method. And 350°C, 450°C, 550°C and 650 °C short oxidation test and 550 °C cyclic oxidation test. By scanning electron microscopy (SEM) and electron spectrometry (EDS) to analysis micro-structure and phase structure of test samples, study TiN film on oxidation resistance, and utilize indentation method to measure mechanical properties. Results show: In a short time under oxidizing conditions, at 550 °C the TiN film still has a good oxidation resistance. The film still have a sufficient bonding strength below 600 °C.

Abstract: Potential benefits of advanced composite materials, such as 3D composites, include reduced weight, superior stiffness, and good design flexibility [. 3D composites is weaved the fibers into preform firstly and then impregnated to a part. The impregnation quality is a key factor to the part performance; some imperfections resulting from it affect the integration, which limit its usages in aerospace, national defense and other areas. The infusion from both inside and outside at same time (IIOS) is suggested to improve the quality and increase the filling efficiency.

Abstract: Self-lubricant roller bearing from composite material of caprolactam, carbon fiber, and graphite was made. And its molding process was discussed. Its friction and deformation performance was studied. Moreover, different varieties of yarns were spun in the spinning machine for contrast tests. The results show that: The yarn from the machine with this bearing has better quality and without any oil-polluted yarn. And oil cost is only 0.05% of a ordinary oil bearing. As well as its labor is reduced. Thus it can bring greater economic value for enterprises.

Abstract: The equilibria phase of the ternary systems NaCl-CsCl-H₂O was studied at 50°C by the isothermal evaporation method. The equilibrium phase diagrams were plotted in line with the experimental data. It suggest that the phase diagram of NaCl-CsCl-H₂O is the simple eutectic type where one invariant point is found to have the compositions of 12.3% NaCl, 54.1% CsCl and 33.6% H₂O by mass, respectively. The study provide fundamental thermodynamic data of brine system that contains sodium and cesium, and has practical significance for the brine’s comprehensive utilization.

Abstract: Chitosan-based films containing lavender essential oil (LEO) (0, 0.5%, 1.0%, 1.5% (v/v)) were prepared to evaluate their physical and antibacterial activities. In order to study the impact of the incorporation of LEO into chitosan matrix, the solubility, mechanical property, water vapor permeability, and antibacterial activity of the films were investigated. Fourier transform infrared chromatography (FTIR) was carried out to explain structure–property relationships. Results showed that the solubility and water vapor permeability of the chitosan-based film decreased by LEO incorporation. Films containing LEO showed better mechanical property. FTIR spectra demonstrated good interaction between functional groups of chitosan with LEO. With the concentration of LEO increased from 0 to 1.5 %, the inhibitory zone of four bacterial strains (Escherichia coli, Staphylococcus aurous, Bacillus magaterium, Bacillus subtilis) increased. It can be concluded that chitosan films containing LEO can be used for development of active food packaging materials.

Abstract: To predict soluble solids content (SSC) of jujube fruits, a hyperspectral imaging technique has been used for acquiring reflectance images from 200 samples in the spectral regions of 900-1700nm. Hyperspectral images of jujubes were evaluated from the regions of interest using principal component analysis (PCA) with the goal of selecting five optimal wavelengths (1034, 1109，1231，1291 and 1461nm). Prediction model of SSC (Rp=0.9027, RMSEP=1.9845) were built based on BP neural network. This research has demonstrated the feasibility of implementing hyperspectral imaging technique for sorting jujube fruit for SSC to enhance the product quality and marketability.

Abstract: The polypropylene luminescent fiber containing Sr₂MgSi₂O₇: Eu²⁺, Dy³⁺ phosphors was prepared by melt-spinning method. Crystal phase structure, spectral features and afterglow properties of the luminescent fiber were tested and analyzed. The results show that the fiber has independent superposition phase features of both Sr₂MgSi₂O₇: Eu²⁺, Dy³⁺ and polypropylene; the range of its excitation light wavelength locates among 250~450 nm; it can emit blue light of 460 nm wavelength; its initial luminescent intensity is more than 600 mcd/m², and afterglow time lasts 7 h; the process of afterglow decay consists of fast stage and slow stage.

Abstract: Two kinds of exfoliated graphite have been prepared from graphite flake and graphite powder, and their preparation conditions were respectively optimized by orthogonal experiments and parallel experiments. The effect of graphite size on the characteristics of exfoliated graphite was researched. The microstructure of two kinds of exfoliated graphite was measured by SEM. The results show that the optimal preparation conditions for exfoliated graphite flake are as following: the mass-volume ratio of graphite to mixed acid is 1: 4, the volume ratio of nitric acid to phosphoric acid is 1: 2, the mass ratio of graphite to potassium permanganate is 1: 0.1, and the reaction temperature is 25°C. For exfoliated graphite powder, the optimal mass ratio of graphite powder to potassium permanganate is 1: 0.22, and the consumption of oxidant for exfoliated graphite powder is more than that for exfoliated graphite flake. The longitudinal expansion of graphite flake is more apparent than that of graphite powder and leads to a worm-like fluffy rope.