Advanced Materials Research Vols. 284-286

Abstract: There were little works about electrochemical corrosion behaviors that appeared in high H₂S and CO₂ containing environment. In this work, the electrochemical behaviors of tubular steel API-P110 in buffered acidic NaCl solutions saturated with high H₂S and CO₂ containing gases, were investigated by potentiodynamic sweep technique. Analysis of the results shows corrosion density declines with increasing CO₂ content in H₂S/CO₂. The corrosion potential of steel moves towards more negatively with the increase of CO₂ content in H₂S/CO₂. In pH 2.9 solution, Passivity appears in high H₂S and CO₂, but no passivity shows in due to decreasing in high H₂S. In pH 5.3 solution, cathodic liming density comes out and increases with the increasing CO₂ content in H₂S/CO₂, however, no cathodic liming density comes out in H₂S.

Abstract: Various non-chemical water treatment methods have been utilized to solve fouling problems. All of these methods have never been scientifically proven to be a valid tool for controlling scales, and one of reasons could be the lack of understanding of the operational principle and treatment mechanisms. The present study focuses on characteristics of calcium carbonate crystal size distribution in solution and crystal structure on the surface under the electromagnetic field in order to comprehend the mechanisms of the Electromagnetic treatment device (ETD). An electromagnetic treatment setup was built for treating scaling water, and a series of fouling tests were carried out with and without ETD, analyzing the particles size distribution in solution by Dynamics Light Scattering (DLS) technology and making Scanning Electron Microscope (SEM) photos. The main results were as follows：The number of precipitate nucleation in solution was few and the particle growth was slow without ETD. In opposition to the case untreated, a rapid particle growth was observed and the number of nucleation was expected to be more, due to the ETD effectively increasing the ions and crystals collision frequency and effectiveness by utilizing the induced electric field. It was implied that the particle growth was promoted mainly by coagulation process but not nucleation growth in all the experimental temperature range. In the high temperature, the crystal phase of calcium carbonate could be changed from aragonite type without ETD to calcite with ETD. In the lower temperature, all the precipitated crystals in solution were calcite and there were little differences between with ETD and without ETD.

Abstract: Three Fe-P-O catalysts were prepared by different methods. The as-prepared catalysts were comparatively characterized by N₂ isothermal adsorption-desorption, XRD, SEM and Py-IR techniques. The reactivity of these catalysts was tested in the benzylation of benzene with benzyl chloride. So-gel prepared Fe-P-O catalyst showed the highest activity among these catalysts and could keep high reactivity even after six reactions cycled because it is not only the large-surface-area superfine particle but also has a large amount of weak and medium Lewis acid sites.

Abstract: Direct electrochemical reduction of Cr₂O₃ pellets in molten CaCl₂-NaCl mixture salt was investigated by 3.0V applied potential for 12h at 550°C in the improved cell. The electrolysis products were characterized by SEM, EDS and XRD. This study showed that the reduction production was effected by the position of Cr₂O₃ pellets. Complete reduction of Cr₂O₃ pellets was achieved near the crucible. Incomplete reduction of Cr₂O₃ pellets was achieved near the anode and the complex compound was formed.

Abstract: Hierarchical bis(8-hydroxyquinoline) nickel(NiQ₂) complex has been synthesized with a facile method in a mixed solvent system at 120 °C for 12 h. The molecular formula of the products is speculated by the C, H and N element analysis and thermal gravimetric analysis, and Fourier-transformation infrared spectroscopy was also utilized to measure its structure, which further confirm the molecular formula of the products. The observation of field emission scanning electron microscopy shows that the morphology of bis(8-hydroxyquinoline) nickel complex is flower-like structure. According to the result, it is found that the photoluminescence of bis(8-hydroxyquinoline) nickel complex is stronger than that of 8-hydroxyquinoline, which indicate that inorganic elements played key roles in their luminescence properties.

Abstract: Simple method of determining emission light color in organic light-emitting diodes (OLEDs) with two emissive materials from their electroluminescent (EL) spectra has been presented. The Commission Internationale de l'Eclairage (CIE) coordinates and two EL intensity rates of OLEDs can be simulated with this method. White light OLEDs were fabricated with a blue light emission from 4,4'-bis[N-1-napthyl-N-phenyl-amino]biphenyl (NPB) and a yellow light emission from bis[2-(4-tert-butylphenyl)benzothiazolato-N,C2’]iridium (acetylacetonate) [(t-bt)2Ir(acac)], and the device shows the CIE coordinates of (0.34, 0.32) at 10 V bias, which located in white light region.

Abstract: SrAl₂O₄:Eu²⁺,Dy3+ long persistence phosphors are synthesized by combustion method. The effects of several processing conditions such as the mole ratio of urea and metal nitrates, initiating temperature, the amounts of fluxing agent(boric acid), and raw material ratio（Sr:Al）on phase composition and subsequent on the spectroscopic properties are studied. The results show that the phase composition changed from strontium-rich phase to aluminium-rich phase with the increasing of initiating temperature, the increasing of the content of urea and boric acid, and with the decreasing of Sr:Al. The results indicate that the sample has most excellent luminescence performance is not the one which has pure single phase SrAl₂O₄, but the one has little impurity phase SrAl₄O₇. Similar phenomenon is also present when synthesized by high temperature solid-state method and microwave plasma synthesis method, so the differences among three methods are also discussed in this paper.

Abstract: In this paper, the transmission characteristics of rubidium excited state Faraday anomalous dispersion optical filters at 532nm for a practical and important wavelength are analyzed and discussed. A weak magnetic field method is employed to calculate the transmission characteristics versus external magnetic field, laser pump power, cell temperature and cell length for natural Rb, ⁸⁵Rb and ⁸⁷Rb atomic vapors, respectively. The theoretical results show that the transmission property of ⁸⁵Rb atomic vapor is superior to that of Rb, ⁸⁷Rb atomic vapors in the weak magnetic field, which makes it more suitable for the magneto-optic filtering material of Faraday optical filters by comparison with natural Rb atomic vapor.

Abstract: The recovery current is an important parameter that influences the performance of the DC power supply based on the power CT in a high voltage active electronic current transformer. It is closely related to the saturation state of the core of the transformer, which harvests energy from the magnetic field generated by the current through the high voltage power line. The recovery current of three types of core material are systematically discussed in terms of their characteristics, which are the Silicon Steel, the Nanocrystalline Alloy, and the Fe-based Amorphous. The closed core of the Nanocrystalline Alloy and Fe-based Amorphous has the feature of low recovery current. Both of them can carry out a lower recovery current within 0.5A in the DC power supply; The gapped core of the Silicon Steel is able to work at the highest recovery current among the three types of cores in the same dimension, which benefits the higher input current of the DC power supply, beyond 2000A. Resultant data of analysis provides a prospective reference for design of the DC power supply with a wide range of input current by application of the combined cores.

Abstract: Using vanadyl acetylacetonate (C₁₀H₁₄O₅V) as precursor, use Tantalum Ethoxide (Ta(OC₂H₅)₅) and Tetrabutyl titanate （C₁₆H₃₆O₄Ti）as doper, by sol-gel method fabricate Ta, Ti mono doping and Ta-Ti co-doped V_1-x-yTa_xTi_yO2 thin film. XRD spectrum indicated that the film was oriented in (011) direction. XPS results indicated the valence state of V, Ta, Ti in the film is +4, at all. While Ta mono doping, single 1at.%Ta can deduce the phase transiton temperature (T_t) by 7.8°C, phase transition hysteresis (ΔT) by 1°C. When the doping rate is 6at.%, T_t=22°C, ΔT=1°C. Ti dopings has little affection to T_t but deduce ΔT obviously. Ta-Ti co-doped V_0.93Ta_0.06Ti_0.01O₂ film thin films without phase transition hysteresis were also fabricated, and its TCR is as high as -7.58%/K at 25°C.