Advanced Materials Research Vols. 239-242

Abstract: Rare earth (RE) ternary complexes of Eu_0.5Ln_0.5(NPPD)₃×DPQ (HNPPD = 1-(naphthalen-2-yl)-3-phenylpropane-1, 3-dione; DPQ = Dipyridobenzoquinone; Ln³⁺ = Nd³⁺, Er³⁺, Ce³⁺, Dy³⁺), Eu_1-xY_x(NPPD)₃×DPQ and Eu_1-xLu_x(NPPD)₃×DPQ (x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9) were synthesized by the reaction of RECl₃×6H₂O with HNPPD and DPQ in stoichiometry. The UV-vis and fluorescence properties of the complexes were investigated. The experimental results show that the luminescence efficiency of Eu³⁺ complexes was enhanced by doping some other lanthanide ions.

Abstract: Hole doped double perovskite compounds (Sr, Na)₂FeMoO₆ with the Na content of x = 0, 0.02, 0.03, 0.07 and 0.17 have been synthesized by sol-gel method. Effects of hole doping on the crystal structure and magnetic properties of Sr₂FeMoO₆ have been investigated. XRD pattern indicates that all the samples are of single phase and belong to the space group I4/m. The degree of cation ordering in the Na-doped Sr₂FeMoO₆ compounds shows a non-monotonic variation with the doping level. The saturation magnetization of the compound increases with x for x<0.17. Similar to the electron doped Sr₂FeMoO₆, provided that the doped hole enters selectively the spin-down band, the variation of the saturation magnetization can be explained in light of the ferrimagnetic model (FIM).

Abstract: The paper addresses the assessment of the high-temperature oxidation behavior of T91 in supercritical boilers. The trend to higher steam temperatures and longer periods of full-load operation greatly increases the oxidation corrosion on the steam-side surface. The oxide films can lead to major failures and consequently to reduced plant availability. The exfoliation of the oxide scale may block the tubes somewhere in the system with the potential for causing tube explosion. The oxide scale of T91 was sampled and analyzed by the energy dispersive X-ray spectrometry (EDXS) and the X-ray diffractmeter (XRD). The mechanism of oxidation corrosion and scale exfoliation, as well as its influence factor, were described. The measures were brought forward so as to provide a scientific guidance for dealing with oxidation corrosion and oxide exfoliation on a large scale in T91 in the supercritical boiler.

Abstract: The article main discusses the development, production and application of directional multi -microtubule purging plugs which used in large or medium sized bottom blowing converter. This type of purging plug makes the gas flow in the metal pipes with very small resisting force and good air tightness. It is produced by using cold isostatic pressing, and has high strength and good corrosion resistance. Mainly employed high purity fused magnesia, flake graphite as raw material, and used phenolic resin as binder, and added titanium carbide, boron carbide as antioxidants and additives, which improved anti-oxidation, corrosion resistance and washing resistance, and the life of purging plug is highly improved accordingly.

Abstract: With polylactic acid (PLA) resin as walls and capsaicin as core substances, microcapsules were prepared based on diphase emulsion method. The microcapsule characteristics such as the particle size, inner structure and properties were investigated. The morphology and size distribution of the microcapsules were analyzed by laser particle size analyzer and scanning electron microscopy (SEM). The microcapsules had a mean diameter of about 60~120 µm. In addition, their thermal properties were measured by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was demonstrated that the melting point and thermal stability were improved or changed compared with that of the pure capsaicin. These phenomena were caused by the encapsulated PLA resin over the surface.

Abstract: The acid dipping-plating pretreatment was applied on iron substrate prior to no-cyanide copper plating process. After being pretreated in dipping solution, the thin copper film formed on iron substrate which could change the cathode electronic potential and enhance the copper plating rate in the follow-up copper electroplating. As a comparation, the iron substrate was directly electroplated in another copper plating bath without dipping-plating pretreatment (DPr). The effects of temperature and electric current density on the copper plating rate were investigated in both process with DPr and process without DPr. And the mechanism was discussed.

Abstract: We reported the preparation and electrochemical properties of fluorinated mesoporous carbon foams (F-MCFs) for application as electric double-layer capacitors (EDLCs). By using fluorinated resol which was obtained from the polymerization of formaldehyde, phenol, and 3-fluorophenol as the carbon source and fluorin precursor, and triblock copolymer F127 as a template, F-MCFs were prepared through evaporation induced self-assembly strategy. The F-MCFs were characterized by N₂ adsorption and desorption, transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). The results indicate that the F-MCFs possess highly ordered mesostructure with a specific surface area of 675 m²/g, a uniform pore size of 2.2 nm and a pore volume of 0.12 cm³/g. The wettability of F-MCFs was investigated by contact angle analysis. The contact angle of F-MCFs for water is 111.5^o, much lower than that of mesoporous carbon foams (MCFs) (141^o), indicating that the surface wettability of F-MCFs is improved by the introduction of fluorin into the carbon matrix. The enhancement of wettability would increase the surface contact of electrolyte and electrode and accelerate the ion transfer within the pore channel, and thus improve the electrochemical properties of F-MCFs. The electrochemical properties of the F-MCFs have been investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge in electrolyte of 6 mol/L KOH with a three-electrode system. F-MCFs present linear galvanostatic charge-discharge curve at a loading current of 10 mA, and possess good charge-discharge efficiency over 98%. The specific capacitance of the F-MCFs is 220 F/g, significantly higher than that of the MCFs (140 F/g). F-MCFs show important prospect as electrode materials for the application in EDLCs.

Abstract: In this paper, the powder of SrZnO₂ was prepared by 1050°C solid-state reaction. The catalysis of SrZnO₂ to the depolymerization of PET under microwave irradiation was studied under different temperatures. The results showed that the depolymerization rate of PET was reached 92.6% at 180°C when the reaction time was 220min. It was also found that the depolymerization rate of PET catalyzed by SrZnO₂ was more than that of without catalyst under microwave irradiation.

Abstract: Poly(Ethylene Terephthalate)(PET)/carbon black(CB) composite was prepared by melt blending using a separate feeding technique. The non-isothermal crystallization process of virgin PET and PET/CB composite were investigated by differential scanning calorimetry (DSC) and the different methods such as Jeziorny modified Avrami equation, Ozawa equation and the method developed by Mo were employed to analyze the non-isothermal kinetics of virgin PET and PET/CB composite. The results show that the CB particles dispersed in PET matrix act as heterogeneous nucleating agents, while CB particles hinder the movement of molecular chains of PET, meanwhile, the crystallization activation energy(⊿E) of PET/CB composite is much greater than that of virgin PET according to Kissinger formula, which is opposite to the low CB content condition. This indicates that CB particles reduce the rate of crystal growth. Whereas, the results obtained from the mentioned three methods simultaneously demonstrate the addition of CB greatly increases crystallization temperature and crystallinity and accelerates crystallization rate. Taking the two seemingly contradictory results, crystal growth has little effect on the crystallization rate and crystal nucleation dominate the crystallization process of PET/CB composite with very high CB content. According to Jeziorny method, the constant of crystallization rate (Z_c) increases with the increment of cooling rate and Avrami index (n) doesn’t change significantly, but the Z_c and n of PET/CB composite are greater than that of PET. Based on Ozawa method, lg[-ln(1-X_t)] and lgR don’t show a good linear relationship. The parameter F(T) increases significantly with the increasing of relative crystallinity and n is almost unchanged. Besides, the F(T) of PET/CB composite is less than that of PET, while a is greater than that of PET. Comparing with Ozawa and Avrami equation, Mo method can better describe the non-isothermal crystallization of PET and PET/CB composite.

Abstract: The microstructure and tensile properties at room temperature of as-extruded Mg_94.5Zn₄Y₁Er_0.5 alloy sheet were studied. The results show that the alloy is mainly composed of equiaxial-liked α-(Mg) grains and W phase containing lots of rare earth elements (F.C.C. structure, a=0.707nm). The elongation and tensile strength of the alloy sheet in hot extruded and transverse direction are 25.5 %, 29.9 % and 247 MPa, 240 MPa, respectively. The above results manifest that the W phase stimulate the DRX during hot extrusion, reduce the preference of basal texture of magnesium alloy, markedly improve the plastically shaping capability at room temperature.