1,721,027 research outputs found
Effect of LaNiO3 top electrode on the resistance of Pb(Zr,Ti)O-3 ferroelectric capacitor to hydrogen damage and fatigue
No full textThe polarization hysteresis characteristics of Pb(Zi,Ti)O-3 (PZT) capacitors with a Pt top electrode are degraded by annealing in a hydrogen-containing environment due to the catalytic effect of Pt. This degradation can be avoided by adopting an LaNiO3 (LNO) conductive film as a top electrode. The LNO film does not act as a catalyst for the dissociation of hydrogen molecules and it is also a good diffusion barrier to the hydrogen molecules. The resistance of the LNO film to hydrogen degradation is further enhanced by inserting a thin Pt layer between the LNO and PZT films due to the blocking ability of Pt against the out-diffusion of the Pb component from the PZT film. The polarization characteristics of LNO/Pt/PZT/Pt capacitors are well preserved after hydrogen annealing even at 400degreesC for 30 min. The use of the LNO film as a top electrode also has a significant effect on improving the fatigue property of PZT capacitors.This research was supported by the Center for Electronic
Packaging Materials of Korea Science and Engineering
Foundation
Application of Spinel-Type Cobalt Chromite as a Novel Catalyst for Combustion of Chlorinated Organic Pollutants
Full text linkVarious chromium-containing; catalysts were tested fdr the total oxidation of trichloroethylene (TCE) as a model reaction for the catalytic combustion of chlorinated organic pollutants. A spinel-type cobalt chromite (CoCr(2)O(4)) among others was proven to be a very promising catalyst showing higher activity and higher CO(2) selectivity than traditional alumina supported chromia. Even if both Cr(3+) and Cr(6+) species were observed on the surface of CoCr(2)O(4), the Cr(6+) species was stable under reducing environment. The presence of Cr(3+)-Cr(6+) pair sites and the effect of red ox treatments on the activity were investigated to explain the nature of possible active sites for TCE decomposition. Higher selectivity to CO(2) of CoCr(2)O(4) was ascribed to the abundance of its Cr(3+) species, together with its activity for water gas shift reaction
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Low temperature growth of ZnO thin film by metalorganic chemical vapor deposition
No full textPolycrystalline ZnO thin films with a preferred orientation were successfully grown by metal organic chemical vapor deposition at temperatures <= 300 degrees C. By injecting additional Ar gas through a by-pass line, good quality ZnO films were grown at low temperature. The ZnO films grown at substrate temperatures < 200 degrees C showed a porous microstructure whereas a dense undoped ZnO film showing a high conductivity and no Zn phases was grown at 210 degrees C. The ZnO film grown at low temperatures by MOCVD showed improved emission properties compared with the films grown by sputtering. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Synthesis and microstructural characterization of growth direction controlled ZnO nanorods using a buffer layer
No full textThe growth direction and morphology of one-dimensional ZnO nanostructures grown by metal-organic chemical vapour deposition (MOCVD) were modulated by changing the growth temperature of previously deposited ZnO buffer layers that were used as a template. The ZnO nanorods grown on the low-temperature deposited buffer layer were regularly inclined with respect to the substrate surface and show in-plane alignment with azimuthally six-fold symmetry. In contrast, deposition of the buffer layer at higher growth temperature led to the formation of vertically well-aligned ZnO nanorods. In addition, the ZnO nanorods grown on the buffer layer deposited at low growth temperature show a growth direction of [10 (1) over bar0], unlike the conventional ZnO nanorods showing a growth direction of [0001]. The microstructural analysis and atomic modelling of the formation of regularly inclined nanorods using transmission electron microscopy are presented
Low-temperature deactivation and oxidation state of Pd/gamma-Al2O3 catalysts for total oxidation of n-hexane
No full textFive weight percentage of Pd/gamma-Al2O3 catalysts were used for the oxidation of n-hexane. The activities of catalysts were greatly influenced by pre-treatments. The hydrogen-treated catalysts mainly with metallic palladium showed higher oxidation activities than the air-treated catalysts mostly with palladium oxide, even if the palladium oxide was known to be the active phase for high-temperature combustion of methane. The XPS and XRD analyses suggested that the oxidation state of palladium did not change during oxidation reaction at lower temperature of 180 degreesC. The reduced catalysts whose initial activities at lower temperatures were higher than the oxidized catalysts showed a gradual deactivation. This kind of low-temperature deactivation was attributed to the deposit of carbonaceous intermediates, which were evidenced through temperature-programmed analyses such as TGA and TPO. (C) 2004 Elsevier B.V. All rights reserved
Effects of buffer layer thickness on growth and properties of ZnO nanorods grown by metalorganic chemical vapour deposition
No full textWe investigated the effect of the buffer layer thickness on the structural and optical properties of ZnO nanorods grown on Si substrates by metalorganic chemical vapour deposition. Increasing the thickness of the buffer layer significantly enhanced the vertical alignment and density of the nanorods. The ZnO nanorods grown on the buffer layer with a thickness exceeding 500 nm were inclined on the substrate surface, due to the formation of a rugged morphology with a pyramidal shape on the surface of the buffer layer, which was attributed to the surface undulation resulting from the increased tensile strain. This inclination also resulted in a decrease in the intensity of the (0002) ZnO diffraction peak and the ultraviolet emission peak. This paper discusses the microstructural properties and growth mechanism of the ZnO nanorods on buffer layers with various thicknesses
Growth and characterization study of multidimensional hierarchical ZnO nanostructures
No full textZnO multidimensional hierarchical structure was successfully fabricated with the sequence of ZnO top layers/ZnO nanorods/ZnO buffer/Si(111) substrate by continuous controlling growth condition in metal organic chemical vapor deposition (MOCVD) system. Transmission electron microscopy (TEM) showed that ZnO nanorods in hierarchical structure had a single crystal hexagonal wurtzite structure with (0001)(ZnO) growth direction. Only near band edge (NBE) emissions with very weak deep level emission are observed around 3.28 eV. This indicates that ZnO hierarchical structure grown by MOCVD shows a good optical quality and less interior defects. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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