Advanced Materials Research Vols. 875-877

Abstract: Nanocrystalline titania (TiO2) thin films prepared by spray pyrolysis deposition on to the heated glass in a temperature range of TS = 350 ÷ 450oC. Analysis of optical transmission spectral of films reveals an optical band gap of about 3.2÷3.4 eV and the transmittance above 80% for TiO2 films with thickness of 0.8÷1.6 µm. X-ray diffraction (XRD) analysis demonstrates that the films are found of anatase phase in crystal structure. The AFM photographs show the nano-size of the constituents. The crystallize size and crystalline of the samples is discussed with respect to the film thickness and deposition temperature.

Abstract: Mn2+ activated ZnO-B2O3 glasses show bright and long-lasting phosphorescence (LLP). After irradiation by 254nm light, a visible red light with dominating peak at 600nm can be observed with the naked eye in the dark for up to 12h after removal of the activating light. We examined the luminescence properties using fluorescence, phosphorescence spectra and thermostimulated luminescence (TL). This phosphorescence arises from d-d transitions of Mn2+ ions. The thermostimulated luminescence (TL) intensity increases with the increasing of Mn2+ concentration from 1×10-3 mol % to 1×10-1 mol %. The decay curve of the LLP is consistent with the TL releasing velocity raised from defects of 420K. Based on the fact, we suggest that LLP is a special kind of thermostimulate luminescence. The storage and releasing of energy is closely associated with properties of defects, while the properties of LLP are related to both the defects and luminescence centers.

Abstract: Poly(methyl methacrylate) (PMMA) latex particles stabilized by chitosan (CS) or N,N,N-trimethylated chitosan (TMC) (50% degree of quaternization) were prepared via the miniemulsion polymerization. The spherical PMMA-CS nanoparticles (342 nm) were then deposited onto sulphur-prevulcanized natural rubber (SPNR) film via the Layer-by-Layer (LbL) technique. The aims were to reduce the surface friction of rubber film and to avoid the direct contact between SPNR and human skin which might cause the allergic problem for some hypersensitive users. Results confirmed the presence of PMMA-CS particles which caused an increase in the surface roughness of SPNR from 46 to 57. However, the PMMA-CS did not exhibit the antimicrobial activity. Therefore, the antimicrobial activity against E.coli and S.aureus of the SPNR film coated with PMMA-TMC particles is investigated.

Abstract: In this work, ECAP technique was combined with cold rolling process in order to enhance mechanical properties and microstructure of pure Titanium. Coarse grain (CG) Titanium with original grain size of 150 μm had been pressed by ECAP at 425oC by 4, 8 and 12 passes, respectively. This process then was followed by rolling at room temperature with 35%, 55%, and 75% rolling strains. After two steps, mechanical properties such as strength, hardness and microstructure of processed Titanium have been measured. The result indicated significant effect of cold rolling on tensile strength, hardness and microstructure of ECAP-Titanium.

Abstract: A Self-Compacting Concrete (SCC) is by definition one that, due to its own weight, pours and sets in place in the most complex reinforced moulds. It is important to note that the material must not undergo any form of segregation, whether “dynamic”, i.e. when it occurs during flowing, or “static”, i.e. when it occurs in the mould after compaction of different materials in the concrete. In this paper, study of static resistance segregation of self-compacting concretes is presented. Experimental assessment of segregation is carried out by procedure, which is realized in this paper. This procedure is similar to column test but different cylinder geometry and splitting is carried out at the end of setting. For each of the different mixtures studied, we also measure the slump flow, the filling ratio (L-box test), the screen stability and the V-funnel flowing time. The results obtained show that in the case of SCC, specific tests must be carried out to assess static segregation, especially when slump flow is above 70 cm. This study also shows that it is possible to obtain high quality SCC (with no risk of segregation) with screen stability test values in the region of 30%, which are much greater than the usual 15% recommended pat the French association of civil engineering AFGC [1].

Abstract: Nanocrystalline TiO₂ was prepared using sol-gel hydrothermal method to be used as photoelectrode material for dye solar cells (DSC) employing continuous stirring of titanium tetrachloride (TiCl4) with hydrochloric acid (HCl) and deionized water at 70 oC for 6 hours. TiO2 nanopowder was obtained after calcinations in air at 400 oC. The samples were characterized using FESEM, TEM, XRD, BET and UV-Vis optical absorption. This paper discusses the effect of surfactant on the physicochemical properties and the efficiency of the synthesized TiO₂ photoelectrode to convert light into electricity.

Abstract: Formaldehyde, a colorless and pungent-smelling gas, had been confirmed be a huge threat to people health. The detection of formaldehyde was necessary and important at room temperature. Sprayed P3HT/InSnO composite film based on organic thin film transistors (OTFT) was fabricated to detect formaldehyde at room temperature in this paper. The results showed that P3HT/ InSnO-OTFT showed better response and recovery to HCHO compared with P3HT-OTFT at room temperature.

Abstract: The film-forming potential of isolate of seed polysaccharide from Cassia fistula was investigated. Increasing the glycerol concentration in the film increased elongation at break, film solubility and water vapor permeability but decreased tensile strength (TS). The film impregnated with the acetone extract of Atractylodes lancea was assessed for inhibition of Escherichia coli and Staphylococcus aureus. The obtained results showed that the films exhibited antibacterial activity against both bacterial strains. Disc-diffusion assay revealed that the film resulted in a larger inhibition zone around the film on Staphylococcus aureus than it did on Escherichia coli at the same extract concentrations (0.1 to 0.9 wt %). It can be seen that the film has satisfactory physical and antibacterial properties.

Abstract: The treatment technics for substrate was researched and improved by experimentations, the technics and additive research of plating for forming ornamental and functional multicomponents alloy was carried out completely, the optimum technics of plating multicomponents alloy was been found. The coatings made by optimum technics were with excellent corrosion-resistance ,wear-resistance, oxidation-resistance and with a smooth, fine, shining surface. It was proved that the 8.9% phosphorus in the coating and the coating was amorphous crystal by determinations. And it was found that the combination force between the substrate and the coating was vary good and the properties of coating to resist corrosion and abrasion were much better than that of Ni-P alloy through the tests.The coating was finery in ornamentally also.

Abstract: In order to control the FePO₄ particles size, the reaction precipitation between Fe (NO₃)₃ and H₃PO₄ was performed by the controlled crystallization technique. The influences of the feed concentration, stirring speed and reaction temperature on the agglomeration size of FePO₄ were investigated. The particles produced were amorphous and can be crystallied to pure phase FePO₄ after calcining at 550 °C for 5 hours. The agglomerates size and morphology were characterized by the laser granulometer and scanning electron microscope, respectively. The results showed that the products were spherical and the agglomerate size was in the range of 2~9 μm at the solution PH 2.30 and the other experiment conditions were as follows, the reactant concentration was ranged from 0.5 to 1.0mol/L, stirring speed from 500 to 3000 rpm and reaction temperature from 15 to 80°C. It was found that the agglomerates size increased with the increase of the reaction temperature, decreased with the increase of the feed concentration and stirring speed. Based on the discretized population balance, the particle size distribution model was developed. There was a good agreement between the calculated values and the experimental data, which indicated that this model can be used for predicting the agglomerates size distribution at any desired levels of the variables studied.