Advanced Materials Research Vols. 287-290

Abstract: TCO (transparent conducting oxide) films are widely used as photoelectric devices in flat panel displays and solar cells. Until now, ITO (indium-tin oxide) films have been used as TCO films. However, with the increase in the cost of ITO films , researchers have been searching for new materials to use as TCO films .Transparent and conductive aluminum-doped zinc oxide films were prepared by DC magnetron sputtering at different substrate temperatures. The electric and optical properties of these films were studied by Hall measurement and optical spectroscopy, respectively. All of the films that were deposited at temperatures higher than 200 °C substrate temperature demonstrated over 80% transmittance in the range of the visible spectrum. Since the surface mobility of a particle is limited at a low temperature, the growth rate of AZO thin films would be higher than that at a high temperature. And the films showed minimum resistivity of 6.77 × 10 ^-3 Ω•cm at substrate temperature of 200 °C.

Abstract: In this article, the graft copolymerization of 4-vinyl pyridine onto poly (ethylene terephthalate)(PET) via the potassium diperiodacuprate(III)–PET redox system as an initiator was investigated in an alkaline medium. The graft copolymer was characterized with Fourier-transform infrared spectra analysis. A mechanism is proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, the ratio of monomer to PET, pH, and reaction temperature and time, are investigated, and the grafting conditions are optimized. Graft copolymers with high grafting efficiency are obtained, thus indicating that potassium diperiodacuprate(III)-PET redox system is an efficient initiator for this graft copolymerization. The quaternized PET-g-PVP (QPEVP) is proved to be an excellent adsorbent to heavy metal ions.

Abstract: Electrochemical sensors based on tubular yttria-stabilized zerconia (YSZ) with the perovskite-type oxide as a sensing-electrode (SE), which is prepared by sol-gel method, were fabricated and examined for NO2 detection in the temperature range 673~973K. The results show that La_0.75Sr_0.25Cr_0.5Mn_0.5O₃, shows extreme sensitivity to NO₂. The EMF varies linearly as a function of the concentration of NO₂ (0~ 463 ppm) at 773K.

Abstract: The bioactivity of TiO₂/Ti composite membrane with different crystral phase was studied by the culture of hypothalamic neurons in vitro for the application of immunoisolation. The kind of membrane supported on porous Ti has been prepared by sol-gel technique and the crystral phase was controlled by different sintering temperature. The crystral phase of TiO₂, morphology and function of hypothalamic neurons were observed by X-ray diffraction (XRD), enzyme-linked immunosorbent assay (ELISA) and environmental sanning electron microscope (ESEM). The results showed that neurons could attach well to the TiO₂ /Ti composite membranes with rutile phase and became bipolar. The long axon and dendrite with dendrite spine were interconnected by synapses. A complicated neural net were easily observed. The secretory level of β-endorphine remained between 51.3pmol/L and 40.6pmol/L all the times. However, the neurons in membranes with anatase were transformed into an umbilicate structure without processes. The secretory function of neurons also died out in 4 days. These results indicated that the TiO₂ /Ti composite membranes with rutile phase were propitious to the neuron’s growth than the composite membranes with anatase phase and could be used as immunoisolation membranes.

Abstract: To improve the situation of stress concentration in the combustion chamber component, optimized the design of combustion chamber shell structures is required. In this paper, a new boundary element integrated optimization method is used. There are a symmetry axis structure and effective constrained optimization model for sensitivity analysis. The technology and the general shape optimization algorithm are combined. The components' shape of the combustion chamber's shell under a plane stress is optimized, and finally, the satisfactory results are obtained and the maximum tangential bore stress is reduced.

Abstract: Magnetite Fe₃O₄ nanoparticles of 30-40 nm with a low coercivity are ideal for the hyperthermia applications. The Fe₃O₄ particles were prepared by oxidizing Fe²⁺ iron with a weak oxidant NaNO₃ in a N₂-deaerated aqueous NaOH solution (pH=12-13) at various temperatures below 30 °C. The nucleation features are explored. When the reaction temperature increases, the particle size decreases and the nucleation time shortens. At the two stages of the synthesis reaction, the coercivity is mainly affected by the saturation magnetic flux density and particle size, respectively.

Abstract: Based on an explicit formula used for describing the van der Waals (vdW) interaction between any two layers of multi-layered graphene sheets (MLGSs), the vibration properties of five- and eight-layered graphene sheets are analyzed with considering the influence of vdW interaction on the natural frequences. The present study shows that for a given combination n and m the lowest natural frequency (classical natural frequency) of a MLGSs is independent of vdW interaction, but that it is very significant for the influence of vdW interaction on the other higher frequencies (resonant frequencies). The different vibration modes, including in-phase and anti-phase ones, are given for exhibiting clearly the influence of vdW interaction.

Abstract: Mathematical model of dual media reservoir fracturing wells was established and the corresponding numerical calculation program was developed based on the special relationship between porosity and permeability of dual media low permeability gas reservoirs. Through comparative analysis of numerical results of production performance pre and post fracturing, effects of cross flow coefficient and fracture penetration ratio were well studied. The results show that: after a period of production, pressure decline of the gas well decreases linearly with time, whether fracturing or not, showing pseudo-steady-state characteristics; in the early stage, pressure drop in the vertical well pre-fracturing is an order of magnitude larger than the post-fracturing well in the logarithmic coordinate; the less developed the natural fracture is, the smaller the cross flow coefficient is, and the more significant role the fracturing plays in yield increasing; when the fracture penetration ratio is between 0.25~0.50, it has less impact on production, so it is suggested that the fracture penetration ratio is controlled at about 0.25 in actual dual media dense gas reservoirs.

Abstract: Raw material cost control is becoming an important aspect in the steel enterprise’s cost management, as the raw material cost occupies a large proportion in the cost of product. Therefore, the raw material cost control model which ensures the minimum raw material cost with the qualified contents of chemical ingredients in the product is established. The arithmetic based on Lagrange multipliers is proposed to solve the described model. The model verification provides great support for reducing the cost and configuring resources optimally.

Abstract: FeS nanoparticles with uniform size have been prepared through a facile route using (sodium carboxymethyl cellulose) CMC as soft template. The nanoparticles are about 4-6 nm by observation of transmission electron microscopy (TEM). The CMC template could also stabilize the FeS nanoparticles and resist aggregation. It is important to note that the size of nanoparticles can be easily controlled by the concentration of iron and sulfur source during the synthetic process. Interestingly, the FeS nanoparticles could assemble into rod-like morphology at higher concentration. More importantly, the CMC-stabilized FeS nanoparticles exibit enhanced performance for Cr(Ⅵ) removal as compared with FeS synthesized without CMC stabilizer.