A study on the characteristics of hydrated La2O3 thin films with different oxidation gases on the various annealing temperature

In order to investigate the structural and electrical properties of La₂O₃ films deposited by O₂ and O₃, films were hydrated in DI-water and annealed at 600 and 900 °C. La₂O₃ films deposited by O₃ showed better hydration resistance than those deposited by O₂. The thickness of both hydrated films decreased after annealing at 600 °C and increased after annealing at 900 °C. The dielectric constants of the La₂O₃ films deposited by O₃ were greater than films deposited by O₂ after annealing at 600 °C and slightly less after annealing at 900 °C. The leakage current density of the La₂O₃ films deposited by O₃ was lower than those by O₂ after annealing at 900 °C. To this end, La₂O₃ films deposited by O₃ showed better dissolution resistance than O₂ for hydration experiment as a function of dipping time.     

Magnetic properties of insulating RTiO3 thin films

The magnetic properties of epitaxial RTiO₃ (R?=?Y, Eu) thin films are reported. The films were grown on various substrates with different lattice mismatches using the pulsed laser deposition technique. Ferromagnetic YTiO₃ thin films could only be grown on LaAlO₃ (110) substrates, while EuTiO₃ films could be grown on various substrates. The magnetic properties of the grown films are discussed in light of the structural characterization.     

Efficient and ripple-mitigating dc–dc converter for residential fuel cell system

Proton exchange membrane fuel cell (PEMFC) systems for residential application require efficient and ripple-mitigating power conditioning system (PCS). The key point to reach it, is the design and control of the dc–dc converter. Based on the theoretical and experimental analysis of the traditional converter, this paper proposes a novel parallel-series full bridge (P-SFB) dc–dc converter, and improves its phase shifting scheme. This paper also proposes a novel controller for low frequency ripple current suppressing applied on the converter. The experimental results verify that, the dc–dc converter achieves a peak efficiency of 95.5%. Therefore PCS’s maximum efficiency reaches 92.9%. And the input current ripple is reduced significantly with the new controller.     

Selective CO Gas Detection of Zn2SnO4 Gas Sensor

The ability of semiconductor gas sensors to differentiate between gases is essential but difficult to obtain. In this study, Zn₂SnO₄ was made to be CO selective and the possible mechanism for the selectivity was studied.The electrical and the gas-sensing properties of uncoated and CuO-coated Zn₂SnO₄ were investigated. In order to obtain an ohmic contact to Zn₂SnO₄, a ZnO layer was stacked on top of Zn₂SnO₄ and co-fired. CuO was coated by immersing the sintered sample in Cu-containing solution. Both uncoated and CuO-coated samples showed the higher sensitivity to 200 ppm CO gas than to 200 ppm H₂ gas. However, the CuO-coated Zn₂SnO₄ showed much enhanced sensitivity and thus good selectivity for CO gas (S _CO/S _{H 2} 6) compared to the uncoated sample. The excellent selectivity of Zn₂SnO₄-based materials for CO gas was explained by the difference in the mechanisms of CO and H₂ oxidation.     

Preparation of nano-zeolite tubular membrane for ethylbenzene separation from ternary mixed xylene by microwave functional coating method

The ethylbenzene separation from mixed xylene is one of the critical issues in the chemical industry. In this study, separation of ethylbenzene from ternary xylene mixtures system [ethylbenzene (EB), para-xylene (PX) and meta-xylene (MX)] was performed using a nano-zeolite coated tubular membrane system. Nano-zeolite membranes with different Si/Al ratios (Si/Al = 30, 100 and ∞) were prepared by a microwave hydrothermal method and the separation performance was compared. MFI-type nano-zeolite membranes were synthesized on alumina tubes from the randomly oriented seed layers by dip coating and functional coating using 3-chloropropyltrimethoxysilane, respectively. After the microwave-assisted secondary growth, it was observed that thinner layers of nano-zeolites were prepared by functional coating (3–4 μm) compared to the typical dip coating (6–8 μm). Ethylbenzene separation tests were performed using a comparatively high EB-containing ternary mixture feed (EB/PX/MX = 80/5/15 molar ratio). The silicalite-1 (Si/Al ratio = ∞) membrane with a functional layer shows the best ethylbenzene separation factor of 3.11 from the high EB-containing ternary mixture feed (ethylbenzene flux: 1,010.6 mol/m² s Pa ×10^?10).     

In situ line measurement of mean aggregate size and fractal dimension along the flame axis by planar laser light scattering

An in situ laser light scattering method has been developed for line measurement of aggregate size and morphology. Planar multiangular light scattering measurements were interpreted by using Rayleigh–Debye–Gans scattering theory for fractal aggregates to simultaneously obtain the mean radius of gyration and the fractal dimension along the flame axis, which are the parameters characterizing size and morphology of aggregates. The developed system was applied to study the evolution of silica aggregates produced in a methane/air premixed flat flame. To confirm the suitability of the present method as a line measurement of the growth of aggregates, we compared the results with those obtained by conventional point measurements and it was found that the two results agreed well each other. The comparison of size parameters has been also made with those obtained by thermophoretic sampling and TEM observation.     

Mobile phase composition for resolving whey proteins in reversed-phase high performance liquid chromatography

Reversed-phase high-performance liquid chromatography was successfully developed for the simultaneous and rapid separation for the main whey proteins, α-Lactalbumin and β-Lactoglobulin. This method consisted of a linear gradient of the two mobile phases of 0.1% trifluoroacetic acid in water and 0.1% trifluoroacetic acid in acetonitrile. The total run time for this separation was approximately 30 min, and α-Lactalbumin was eluted followed byβ- Lactoglobulin. The injection volume was fixed at 20 μl and the flow rate was 1 ml 1/min. The optimum mobile phase composition and gradient conditions to separate α-Lactalbumin and β-Lactoglobulin (A+B) were experimentally obtained at the 15 μm particle with a pore size of 300 Å on the linear-gradient mode.