Advanced Materials Research Vols. 535-537

Abstract: A new synthetic technology of Strontium carbonate with ultrasonic is introduced in this article. Ultrasonic wave synthetic technology is a fast and novel method. Spherical SrCO3 powders were synthesized by changing the solvent and reaction conditions using the ultrasonic wave method. The SrCO3 powders were characterized by the XRD and SEM.The results show that the asprepared products were Spherical structure and with high dispersity, the average particle size of the SrCO3 powders synthesized by the ultrasonic wave synthetic technology is 0.3nm~ 0.5nm. Some reaction parameters were investigated during the process.

Abstract: In order to improve their optical property, multi-walled carbon nanotubes (MWNTs) were decorated with europium doped yttria oxide (Y2O3:Eu3+) nanoparticles by co-deposition method, and the products were examined by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and luminescence spectroscopy. Experimental results illuminate that MWNTs can be decorated by the Y2O3:Eu3+ nanoparticles at annealed temperature of 600 and 750°C, respectively. The optical property of MWNTs/Y2O3:Eu3+ nanohybrids shows the most excellent when the MWNTs concentratin is 0.5 wt.% and the molar ratios of Eu to Y is 5:95.

Abstract: Large-scale synthesis of high quality PbSe nanocrystals was conducted with the one-pot method. By this “greener” synthesis route, the use of traditional dangerous pyrophoric trioctylphosphine (TOP) and tributylphosphine (TBP) reagents was avoided. The crystal size and shape were controlled by the reaction time, reaction temperature, and the use of different combinations of surfactants. X-ray diffraction (XRD) and transition electron microscopy (TEM) were used to characterize as-synthesized nanocrystals and demonstrated the rock salt cubic structures and narrow size distributions. More than 3 g of high quality PbSe nanocrystals were synthesized in one reaction by this large-scale one-pot method. The uniform size of as-synthesized nanocrystals promoted the self-assembly of PbSe nanocrystals into large-area ordered superstructures.

Abstract: A rapid solvent-free melting route has been successfully developed for the synthesis of tungsten nitrides with lamellar and solid spherical nanostructures which have considerably different surface areas (106.4 m² g^-1 contrast to 8.3 m² g^-1) by the reaction of WCl6 and NaNH2 at 220 °C for 2-5 h directly, and it is found that the heat insulating property of reaction container plays important roles in the composition, phase, and morphologies of the nitrides. The products were analyzed by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). Their thermal stability and surface area were measured by thermogravimetric analysis (TGA) and BET, respectively. Finally, the possible formation mechanism of tungsten nitrides with different morphologies was also investigated.

Abstract: Analysis of Superhydrophobic surfaces is a hot topic recently because of its potential use on drag reduction, lower flow noise, self-cleaning. This paper used VOF model and Lighthill's Acoustic Analogy to simulate the sound pressure of channel flow, and found when fluid flowed across channels, the sound pressure caused by superhydrophobic surfaces was much lower than that of plane surfaces. The macroscale structures and the air stored in the cavities could lower the turbulence kinetic energy, and that could be one of the reasons why flow causes lower flow noise across the superhydrophobic channels.

Abstract: Due to their special properties, nanomaterials had potential application value, and they could play an essential role in improving mudcake quality, assisting in film-forming, reducing lost circulation, and enhancing wellbore stability. Some nanomaterials, such as nanocomposite filtration-reducing agent, nanocomposite viscosifier, nanosized emulsion lubricant, nanometer organoclay, and so on, were introduced, and all of them had significantly influence on the process of drilling operations. As a result, the application of nanomaterials in the field of drilling fluids are very useful for cleaning borehole, maintaining borehole stability, protecting reservoir, and enhancing oil and gas recovery. Finally, the further application of nanomaterials in drilling fluids is also prospected.

Abstract: A simple method was applied to fabricate phase-pure hollow CuS microspheres. The obtained product was characterized by X-ray diffraction, scanning electron microscopy, photoluminescence spectra and UV-Vis absorption spectroscopy. Further, the catalytic activity of CuS spheres was evaluated by the decolorization of Rhodamine B in the presence of hydrogen peroxide solution at room temperature. The results indicated that the product showed a good optical propertie, and the hollow sphere CuS could be an effective catalytic material.

Abstract: Poly phosphoric acid/ Polyacrilonitrile composite nanofibers (PPA/PAN composite nanofibers) has been fabricated by the electro-spinning of PAN solutions containing different amount of PPA. The prepared nanofibers have been characterized by the using of FT-IR, SEM and XRD techniques

Abstract: Carbonaceous microspheres adsorbents prepared by hydrothermal process have been studied for RhB removal from aqueous solutions. Carbonaceous microspheres were characterized by scanning electron microscopy (SEM) and fourier-transform infrared spectroscopy (FTIR). It was found that there were abundant oxygen-containing functional groups on the surface of the carbonaceous microspheres. The equilibrium data of the adsorption and the effect of pH, initial pollutant concentration and temperature of solution on the adsorption of RhB by carbonaceous microspheres were studied. The carbonaceous microspheres exhibited excellent adsorption capacity for RhB.

Abstract: On the base of the electron energy band structure of graphene obtained by the tight-binding method, the quantized wave vector equation along the circumferential director of the spiral single-walled carbon nanotubes was established through coordinate transformation and periodic boundary condition, and an analytical expression of the electron energy band was derived. MATLAB is used to calculate the energy band curve of spiral single-walled carbon nanotubes with different structural parameters. The characteristic of the energy band curves was analyzed and discussed. The results shows that single-walled carbon nanotubes (n, m) can be identified as metallic with no band gap nearly which satisfies n-m=3q(q is integer), otherwise, the nanotubes is semiconducting and there are band gaps between conduction band and valence band. And the band gap is inversely proportional to diameter approximately for semiconducting tubes.