Materials Science Forum Vol. 724

Abstract: The effects of external stress field f on band gap E_g(D, f) of ZnO nanowires (NWs) in a diameter range of D = 0.6 - 2.0 nm are investigated using first-principles density-function theory for the future application as nanogenerators. It is shown that the E_g(D,0) values decreases with the increasing diameter of ZnO NWs without the stress field. Moreover, E_g(D, f) decreases with increasing of f due to the rapid drop of conduction band maximum of ZnO NWs when D is constant. These findings imply that E_g(D,f) functions of ZnO NWs can be modulated by manipulating D and f, which may be help for design of ZnO nanogenerators with a higher generation output voltage.

Abstract: NiO-doped Al₂O₃ was synthesized with 20 wt% of nickel nitrate using the sol-gel process. P123 as an organic additive added to increase surface area of powder. The phase transformation, thermal evolution and surface morphology of the powder were characterized by XRD, TG-DTA and FE-SEM. The 20 wt% NiO-doped Al₂O₃ /10 wt% Ni composite membrane was prepared by hot press sintering (HPS) following with a mechanical alloying process. Hydrogen permeation flux for 20 wt% NiO-doped Al₂O₃ /10 wt% Ni membrane was obtained as 0.1 mol/m² s at 673K.

Abstract: To obtain alumina powder with large surface area, the precursor sol was prepared by hydrolysis of aluminum isopropoxide and then mixing with trehalose dihydrate. The porous alumina powders were prepared by drying and calcination at 500-900 °C. The specific surface area went up to over 340 m²/g in the alumina powder calcined at 500 °C. The mean pore diameter of the alumina powder was increased by the addition of treahalose dihydrate. The porous alumina powder was successfully prepared by the addition of trehalose dihydrate to the precursor sol.

Abstract: Bluecoke is a new type carbon product that prepared by low temperature carbonization process, which take lignite, long flame coal, not sticky and weak glue coal as raw material. At the same time tar and coke oven gas as by-products can be obtained. Two new technologies of Bluecoke production were introduced based on summary of way of producing Bluecoke by low metamorphic coal, namely the rich oxygen carbonization and the microwave carbonization. Both ways have their advantages and disadvantages. By contrast, the quality of coke and the content of valid gas are better using microwave carbonization, which to follow-up industry chains development significantly.

Abstract: Sn doped SiO₂ nanoparticles have been synthesized using a reverse micelle technique combined with metal alkoxide hydrolysis and condensation. The size of the particles and the thickness of the coating can be controlled by manipulating the relative rates of the hydrolysis and condensation reactions of tetraethyl orthosilicate (TEOS) within the micro-emulsion. The properties of the Sn doped SiO₂ nanoparticles were studied as a function of various processing parameters such as R and H value. The average size of synthesized Sn doped SiO₂ nanoparticles was about in the size range of 20-40 nm and core particle (Sn) 1-5 nm. The Sn doped SiO₂ nanoparticles were characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM).

Abstract: Low pressure membranes such as microfiltration (MF) and ultrafiltration (UF) have been widely used for water and wastewater treatment. However, most MF and UF membranes are made of polymeric materials, leading to limited resistance to external streeses. Ceramic membranes are also used but they are more expensive than the polymeric membranes. In this study, novel inorganic membranes were developed for water treatment applications. Colloidal silica and kaolin were used to form dynamic membranes. Stainless steel filter was used as supports for the dynamic membranes. Laboratory-scale systems were used to evaluate their potential and performance. Water permeability and turbidity removal were monitored to confirm their initial efficiency and long-term stability.

Abstract: This paper investigated synthesis of Lanthanum oxide nanoparticles by precipitation method. Effects of reactant concentration, precipitator and dispersant agent on properties of Lanthanum oxide particles were studied. Lanthanum oxide particles were characterized by XRD and SEM. Experimental results showed that ammonium bicarbonate and PEG20000 were appropriate precipitation and dispersant respectively. The optimum process conditions were as follows: concentration of Lanthanum nitrate was 0.18mol/L, concentration ammonium bicarbonate of was 0.6mol/L, reaction temperature was 30. The average particles size of Lanthanum oxide powders with spherical shape gained was about 188 nm.

Abstract: For the problem it is easy for the film to generate fog and drop in greenhouse, Polyethylene/Ethylene Vinyl Acetate (PE/EVA) composite greenhouse film was prepared by co-blending and extrusion. The impact of preparation parameters and the dosage of anti-fogging and anti-dropping masterbatch on the mechanical properties and non-dropping properties of the film has been investigated by versatile mechanical testing machine, atomic force microscope (AFM), contact angle tester, water bath acceleration method. The results show that the elongation at break and tensile strength of the composite film, contact angle of water and the film have decreased after added the anti-fogging and anti-dropping masterbatch. The addition of the anti-fogging and anti-dropping masterbatch can increase the non-dropping property of the greenhouse film greatly.

Abstract: Porous Si₃N₄ ceramics were fabricated by using different species β-Si₃N₄ as seeds, 5 wt.% Y₂O₃ and Lu₂O₃ as sintering additives. Effects of three types of β-Si₃N₄ seeds and two types of sintering additives on the microstructure and mechanical properties of porous Si₃N₄ ceramics were investigated. The results showed rod-like β-Si₃N₄ grains with finer and high aspect ratio developed in the porous microstructure. The microstructure and mechanical properties of specimens added with Lu₂O₃ and β-Si₃N₄ seeds were better than which of those added with Y₂O₃ and β-Si₃N₄ powder. The flexural strength and average aspect ratio of porous Si₃N₄ ceramics were in the range of 297349 MPa and 5.757.26 with the porosity range of 41.07%44.40%.

Abstract: The electroplating of nickel on the copper sheet for lead tap, which is one of the important parts of the secondary battery, has been conducted to improve functional properties such as electrical, thermal and mechanical properties. Materials used for secondary battery parts were known manufactured as cladding methods with different kind metal bonding by cold-roll process. In this study, the nickel was electroplated on the copper sheet and cold rolled and heat treated to evaluate the functional properties and to determinate the grain growth orientation and to investigate the texture formation. Grain growth direction and texture formation were analyzed by the X-ray pole figure. The influence of texture on the mechanical properties could be quantitatively confirmed by the results from the orientation distribution function and the tensile test. The heat-treated textures of the cold-rolled hybrid copper sheet were also investigated.