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1.
Supported metal catalysts, particularly noble metals supported on SiO2, have attracted considerable attention due to the importance of the silica–metal interface in heterogeneous catalysis and in electronic device fabrication. Several important issues, e.g., the stability of the metal–oxide interface at working temperatures and pressures, are not well-understood. In this review, the present status of our understanding of the metal–silica interface is reviewed. Recent results of model studies in our laboratories on Pd/SiO2/Mo(1 1 2) using LEED, AES and STM are reported. In this work, epitaxial, ultrathin, well-ordered SiO2 films were grown on a Mo(1 1 2) substrate to circumvent complications that frequently arise from the silica–silicon interface present in silica thin films grown on silicon. 相似文献
2.
本文运用一典型的人工神经网络模型─“反向传播”模型,对高氧化态(Ⅱ─Ⅳ)三核金属簇合物的构型分布进行了分析,得到了较好的分类、预报结果为化合物结构分析提供了新的工具。 相似文献
3.
It is shown that steady-state kinetic data do not allow the discrimination between the redox and associated mechanisms of the partial oxidation reactions. A discrimination between these mechanisms was performed using transient experiments. The obtained rate expressions are in agreement with experimental kinetic data for catalytic partial oxidation of o-xylene.
An influence of the conjugate oxidation of a catalyst surface on dynamics and kinetics of the heterogeneous catalytic oxidative reactions is considered. Computing simulation of methane oxidative coupling of methane reaction at lowered temperature and elevated pressure has been performed. It showed that the reaction order with respect to oxygen exceeding unity is consistent with the chain branching mechanism of the reaction in the presence of TiSi2 and TiB2 and showed the important role of the branching chain cycles in the low-temperature OCM reaction at elevated pressure. 相似文献
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Bilayered palladium (30 nm thick)–magnesium (350 nm thick) thin films were prepared using the pulsed laser deposition technique in the presence of various background gases (Ar, He and a mixture He + H2) under different partial pressures (47 and 27 Pa). According to the deposition atmosphere, the Pd/Mg interface shows either a sharp or an extended transition. The electrochemical hydriding properties and the mechanical stability upon cycling of the Pd/Mg film are greatly improved when an extended «intermixing» zone between the Pd and Mg layers is present. The Pd–Mg films prepared under pure helium fulfill these conditions. 相似文献
7.
L. Di Giovacchino F. Angerosa L. Di Giacinto 《Journal of the American Oil Chemists' Society》1996,73(3):371-374
Variable quantities of leaves were added to ripe olives prior to extraction to determine their effect on the quality of the
resulting olive oil. The addition of 1–3% w/w leaves improved the organoleptic quality. An increase intrans-2-hexenal aldehyde content occurred, giving the pleasant flavor of “freshly cut grass.” This compound was produced by the
enzymatic breakdown of 13-L-hydroperoxide of linolenic acid in leaf homogenates. 相似文献
8.
张慧云 《成都电子机械高等专科学校学报》2016,(3):93-95
针对当代大学生的特点,阐述了来自于建构主义的全启发式教学方法的理论,对“金属切削机床与刀具”课程内容进行问题分解,采用以启发诱导、共同协作为核心的全启发式教学方法,对该课程的教学环节进行了合理的设计。 相似文献
9.
In the present paper, a strategy for solving transient thermoviscoplastic problems is described. The general thermal and mechanical coupling phenomena are discussed by assuming material properties to be temperature-dependent and accounting for the mechanical terms in the non-stationary heat conduction equation. Time integration is carried out with an implicit scheme. An interesting version of the three-field approach is presented to obtain an accurate solution for the stress field. Finally, a global product coupling algorithm, in which the unknown nodal velocities and temperatures are solved with a two-step solution procedure is suggested. The proposed fractional step method partitions the initial coupled problem into an isothermal viscoplastic problem followed by a purely heat conduction problem at fixed configuration. Applications in metal forming analyses involving full thermomechanical coupling conclude the paper. 相似文献
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