Advanced Materials Research Vol. 800

Abstract: ZnMoO₄:Tb³⁺ phosphor layers were grown on monodisperse SiO₂ particles through a simple sol-gel method, resulting in the formation of core-shell structured SiO₂@ZnMoO₄:Tb³⁺ sub-microspheres. The resulting SiO₂@ZnMoO₄:Tb³⁺ core-shell particles were characterized by powder X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), transmission electron microscopy(TEM) and photoluminescence(PL). SEM and TEM analysis indicates that the obtained sub-microspheres have a uniform size distribution and obvious core-shell structure. SiO₂@ZnMoO₄:Tb³⁺ sub-microspheres show strong green emission under ultraviolet(275nm) illumination and the emission spectra are dominated by a ⁵D₄→⁷F₅ transition of Tb³⁺(543nm,green) from the ZnMoO₄:Tb³⁺ shells. The optimum concentration for Tb³⁺ was determined to be 5 mol% of Zn²⁺ in ZnMoO₄ host shells.

Abstract: Several purpose-designed adhering ways have been used for silicone adhesive adhering on silicone foam surface. The stress-strain and relaxing properties of the adhered and non-adhered silicone foam have been tested. By contrasting the effect of each adhering way to the silicone foams property and considering each adhered silicone foams SEM profile photo we found out the better adhering way C for silicone foam adhered by silicone adhesive. This adhering way C has small transmissibility, good compatibility, and little effect to the silicone foams property, so it can fit silicone foams applying demand.

Abstract: This work demonstrated the synthesis of SiO₂-P₂O₅-SnO₂-ZnO quaternary porous aerogel by sol-gel followed supercritical carbon dioxide drying, starting from tetraethoxysilane (TEOS) as precursor for SiO₂ and triethyl phosphate, tin (iv) chloride pentahydrate and zinc nitrate hexahydrate as precursor for P₂O₅-SnO₂-ZnO. It has been recorded that prepared P₂O₅-SnO₂-ZnO sol was added to silica sol, then formed the quaternary aerogel by base catalyst. The microstructure, morphology and properties of the quaternary aerogel were studied by TG/DTA, FTIR, solid-state ²⁹Si NMR, BET, scanning electron microscopy (SEM) measurement and BJH nitrogen gas adsorption. The silica aerogels tetrahedral subunit structure and the influence of the loaded oxide have been observed. The results indicated that the quaternary aerogel exhibited average pore diameter of 14.15 nm, cumulative pore volume of 2.31 ml/g, the specific surface area as high as 796.29 m²/g and bulk density of 0.275g/cm³. There were four types of Si (O_1/2)₄ tetrahedral unit structure in the quaternary aerogel. From this study, different chemical bond of P₂O₅-SnO₂-ZnO penetrated into the silica network structure.

Abstract: In this paper, Computational Fluid Dynamics (CFD) was used to simulate the magnetic device for the separation of Fe-base oxygen carrier in chemical-looping combustion system. The simulation was based on the Euler multiphase flow model and the k-ε turbulence model, which uses UDF programming to increase volume source phase. Here, commercial computational fluid dynamics software fluent platform was used to build the air reactor cold flow mathematical model, magnetic field under the conditions of different flow conditions were added for separating the Fe₃O₄ and Fe₂O₃. And the simulation results has an important understanding of the process of scientific significance, and will promote the fundamental understanding and applications of the Fe-base oxygen carrier.

Abstract: Two types of shape-stabilized phase change materials (PCMs) based on polyethylene glycol (PEG) and graphene oxide (GO) were prepared by two different methods, including a simple blending process and esterification reaction. The interactions between PEG and GO for the blending product (PEG/GO PCMs) is physical and weak, while for the grafting product (PEG-g-GO) is chemical and strong. In the PEG-g-GO composites, almost all PEG segments were restricted due to the strong chemical interactions and therefore no endothermic peak was observed in the DSC curve. As the interactions between PEG and GO in the PEG/GO composites is weak and physical, the phase change enthalpy of the PEG/GO composites is as much as 163 J/g when the PEG content is 90 wt%. The result indicates that the shape-stabilized PCMs with weak physical interactions are more proper for thermal energy storage than that with strong chemical interactions.

Abstract: TiO₂/tourmaline composite photocatalyst was prepared by sol-gel method using tetrabutyl orthotitanate (Ti (OC₄H₉)₄) as a precursor. As a comparison, pure TiO₂ was prepared at the same experimental conditons without the addition of tourmaline. The obtained composite photocatalyst was characterized by X-Ray diffraction (XRD) and scanning electron microscope (SEM) and its photocatalytic activity was also investigated through the photodiscoloration of methyl orange (MO) under UV irradiation. The XRD results indicated that, in the composite photocatalyst, TiO₂ existed in the form of anatase and rutile, with the sintering temperature and tourmaline content increasing, the anatase phase trended to the transformation to rutile phase. The SEM results revealed that the nanosized particles of TiO₂ were well dispersed and immobilized on the surface of tourmaline, especially for the sample with 2% tourmaline content. Compared with pure TiO₂, the composite photocatalyst exhibited a higher photocatalytic activity. When the pure TiO₂ was used as the photocatalyst, the MO discoloration ratio only reached 55%. However, the MO discoloration ratio could approach 100% in presence of TiO₂/tourmaline composit photocatalyst under the same conditions. The effects of tourmaline content and sintering temperature on the photocatalytic activity of the composite were studied in this work and the results suggested that the sample with 2% tourmaline content and sintered at the temperature of 550°C exhibited the best photocatalytic activity. Finally, the possible mechanism for the photodiscoloration of MO was put forward.

Abstract: The self-healing polymer material which was embedded microcapsules possesses the ability to heal cracks automatically. The microcapsules were synthesized by in-situ polymerization in an oil-in-water emulsion with urea and formaldehyde as the raw shell material,and epoxy resin (E-51)/ xylene as the core material. The impact of stirring speed on the morphology and particle size of synthetic microcapsules were discussed by optical microscopy (OM), scanning electron microscopy (SEM), and Fourier-transform infrared spectrometer (FTIR).Microcapsules of 400~1500 um in diameter were produced by appropriate selection of agitation rate in the range of 300~600 r/min.

Abstract: In this study, the resins modified with trimellitie anhydride (named ZT3) or phthalic anhydride (named ZT5) during the post-crossing of chloromethyl low crosslinking macroporous poly-styrene resin were prepared, characterized and evaluated for adsorptive removal of o-aminobenzoic acid (OABA) from aqueous solutions. The structural characterization results indicated that the resins possessed predominant micropores surface area and moderate specific surface area. The adsorption performance of OABA onto ZT3 and ZT5 was studied through static and kinetic adsorption experiment with the commercial Amberlite XAD-4 as a contrast. Langmuir and Freundlich isotherm equation could fit the adsorption isotherm of OABA onto ZT3 and ZT5 perfectly. The adsorptions of OABA onto the three resins were all spontaneous exothermic processes with physical characters. Kinetic analysis showed that the adsorption reaction could be approximated by a quasi-first kinetic adsorption equation. Key words: o-aminobenzoic acid; adsorption resin; adsorption kinetic; thermodynamic; che-mical modification

Abstract: The system of PEMFC is nonlinear, people who want to control the nonlinear system directly is hard to come true the goal they want.Characteristic of fuel cells polarization curve is determined by current vary,partial pressure of gasses (hydrogen and oxygen),working temperature,humidity of membrane and so on [. NARMA_L2 controller can transfer the nonlinear system into linear system by concealing the nonlinearities. And Neural networks have been applied successfully in the identification and control of dynamic systems. In this paper, the fuel cell model would be controlled by NAMRA_L2.

Abstract: The microstructure and electrochemical properties of the Al-1Mg-0.1Sn-0.1Ga-xBi alloys were investigated by means of SEM/EDAX and electrochemical measurements, the self-corrosion was tested by using the gas-collecting method. The results show that element Bi in alloys is mainly segregated along the grain boundaries. The addition of Bi increases segregative phases which further activate the alloys to get more negative open circuit potentials, at the same time self-corrosion increases. Al-1Mg-0.1Sn-0.1Ga-0.1Bi has good comprehensive electrochemical properties, with ocp-1.693V (vs Hg/HgO) and self-corrosion rate 0.231 ml·cm^-2 ·min^-1 in 4 mol NaOH solution.