372 research outputs found

    Synthesis of uniformly porous NiO/ZrO2 particles

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    Porous NiO–ZrO2 particles were successfully synthesized using a spray-drying method with polystyrene latex (PSL: 400 nm) as a template and starting materials that included NiO powder (7 nm) and ZrO2 sol (1.2 nm). Porous particles with an average diameter of 4.5 µm and nearly spherical, narrow pores with an average size of ∼300 nm were obtained from the precursor at a pH of 3.7. The Brunauer, Emmett and Teller (BET) surface area of the prepared particles was relatively high—about 27 m2/g. When the solution pH was increased to 9.7, the particle morphology became completely spherical, indicating that the morphology of prepared particles can be controlled by adjusting the pH. Calcinations at 900 and 1200 °C were carried out to estimate the thermal stability of the prepared particles, which had shrinkage of less than 36%. The existence of these pores means that various applications, such as electrodes and catalysts, will be possible for the prepared particles

    CuO/WO3 and Pt/WO3 nanocatalysts for efficient pollutant degradation using visible light irradiation

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    CuO/WO3 and Pt/WO3 nanocatalysts with a nanorod morphology were used for photodegradation of organic compounds using visible light irradiation. Both nanocatalysts were prepared using flame assisted spray pyrolysis method (FASP). The prepared nanocatalysts were mechanically stable during the agitation treatment for the photodegradation test due to good interconnection between WO3 and co-catalysts. The enhancement of photocatalytic activity was observed after the addition of CuO and Pt as co-catalysts. The addition of CuO would change the morphology of WO3 from nanorods to cubic. The optimal concentration of the CuO addition was 0.33 wt.%. A low Pt concentration (0.12 wt.%) was required for optimal photocatalytic activity of the Pt/WO3 nanocomposite. The addition of Pt affected neither the morphology nor the crystallite structure of WO3

    Infantile Erosive Pustular Dermatosis of the Scalp Associated with Klippel-Feil Syndrome

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    ArticleACTA DERMATO-VENEREOLOGICA. 90(2):200-201 (2010)journal articl

    Pylorus preserving pancreatoduodenectomy in a 6-year-old girl with recurrent pancreatitis due to an annular pancreas

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    AbstractThe pancreatitis caused by an annular pancreas rarely needs a surgical management in children. Here, we report a case of a 6-year old girl in whom pylorus-preserving pancreatoduodenectomy (PPPD) was performed for the pancreatitis caused by an annular pancreas. As she had previous operations for duodenal atresia and pancreaticobiliary maljunction, PPPD was chosen as a definitive surgical treatment of annular pancreas. She has been free from symptoms for 2 years after the operation

    Evaluation of the Electronic and Local Structure of Mn in Proton-Conducting Oxide, Ca(Zr,Mn)O3-δ, To Elucidate a Direct Hydrogen-Dissolution Reaction

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    The protonation mechanism in Mn-doped CaZrO3 (CZM), which involves a direct hydrogen dissolution from the surrounding H2 gas, was investigated by thermogravimetry (TG) and X-ray absorption spectroscopy (XAS). The TG results implied the formation of oxygen vacancies in a H2 atmosphere. The Mn K-edge XAS spectra indicated a reduction of the Mn ions and local structure variations around the Mn ion, but the Zr K-edge spectra were independent of the surrounding atmosphere. The amount of oxygen vacancies was smaller with respect to the reduction of the Mn ions, suggesting direct dissolution of hydrogen. Unlike many typical perovskite-type proton conductors, protonation by direct dissolution of hydrogen and not hydration was the predominant reaction in Mn-doped CaZrO3. Our experimental results demonstrated that the hydration reaction was suppressed because the oxygen vacancy was stable in the distorted ZrO6 symmetry in the CaZrO3 crystal host, whereas protonation proceeded by the direct dissolution of hydrogen stabilizing near the Mn ions in the interstitial sites at the distorted MnO6 octahedron symmetry. The experimental results showed that the structural configurations around dopants play important roles in the stabilization of protons in perovskite-type CZM materials. We demonstrated a new group of proton conductors that can overcome issues with conventional proton conductors by utilizing the direct hydrogen dissolution reaction
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