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Modified Ceria-Zirconia Fluorite-Like Catalysts for the Combustion of Methane

Journal of Natural Gas Chemistry 2006年第3期15卷 149-163页

作者： Tatiana Kuznetsova Vladislav Sadykov Lubsan Batuev Ella Moroz Elena Burgina vladimir rogov vladimir Kriventsov Dmitrii Kochubey Boreskov Institute of Catalysis SB RAS Pr. Lavrentieva5Novosibirsk630090Russia

For dispersed ceria-zirconia-based solid solutions prepared via the polymerized complex method and annealed at 700 ℃, effects of bulk doping by Ca, Mn, Co, Bi or Nb cations and surface modification by Mn and Pt on their structural features, surface/bulk oxygen reactivity and catalytic activity in methane combustion are considered. With up to 20 mol% doping, a structural type of homogeneous solid solutions of anion-deficient fluorite with disordered anion vacancies is formed. Doping by transition metal cations or Pt increases the mobility and reactivity of the surface/bulk oxygen. A broad variation in specific rates of methane combustion for the studied systems was observed, suggesting structural sensitivity of this reaction. In general, there is no universal relationship between the oxygen mobility, the reactivity and the catalytic activity in methane combustion, which is explained by the factor of specific methane activation on surface active sites. For the Pt-promoted samples, Pt efficiency in methane activation depends on the Pt-support interaction, and the most favorable ones being mixed Pt/MnOx and Pt/NbOx clusters on the surface of the supports that exhibit high lattice oxygen mobilities.

关键词： Ce-Zr-O Ca Mn Co Bi Nb structural features oxygen reactivity oxygen mobility methane combustion

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The Effect of Tool Construction and Cutting Parameters on Surface Roughness and Vibration in Turning of AISI 1045 Steel Using Taguchi Method

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Modern Mechanical Engineering 2014年第1期4卷 8-18页

作者： rogov vladimir Aleksandrovich Ghorbani Siamak Department of Engineering Technology Machine Tools and Metal-Cutting Tools and Instruments People’s Friendship University of Russia Moscow Russia

This paper presents an experimental investigation focused on identifying the effects of cutting conditions and tool construction on the surface roughness and natural frequency in turning of AISI1045 steel. Machining experiments were carried out at the lathe using carbide cutting insert coated with TiC and two forms of cutting tools made of AISI 5140 steel. Three levels for spindle speed, depth of cut, feed rate and tool overhang were chosen as cutting variables. The Taguchi method L9 orthogonal array was applied to design of experiment. By the help of signal-to-noise ratio and analysis of variance, it was concluded that spindle speed has the significant effect on the surface roughness, while tool overhang is the dominant factor affecting natural frequency for both cutting tools. In addition, the optimum cutting conditions for surface roughness and natural frequency were found at different levels. Finally, confirmation experiments were conducted to verify the effectiveness and efficiency of the Taguchi method in optimizing the cutting parameters for surface roughness and natural frequency.

关键词： Surface Roughness Cutting Condition Natural Frequency Vibration Turning ANOVA Taguchi Method S/N Ratio

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