1,721,113 research outputs found
Reactivity of Carbon Dioxide on Nickel: Role of CO in the Competing Interplay between Oxygen and Graphene
No full textThe catalytic conversion of carbon dioxide to synthetic fuels and
other valuable chemicals is an issue of global environmental and economic impact.
In this report we show by means of X-ray photoelectron spectroscopy in the millibar
range that, on a Ni surface, the reduction of carbon dioxide is indirectly governed by
the CO chemistry. While the growth of graphene and the carbide-graphene
conversion can be controlled by selecting the reaction temperature, oxygen is mainly
removed by CO, since oxygen reduction by hydrogen is a slow process on Ni. Even
though there is still a consistent pressure gap with respect to industrial reaction
conditions, the observed phenomena provide a plausible interpretation of the
behavior of Ni/Cu based catalysts for CO2 conversion and account for a possible
role of CO in the methanol synthesis process
X‐ray Photoelectron Spectroscopy. An Introduction to Principles and Practices. Von Paul van der Heide.
No full text
Hydroxylation of Platinum Surface Oxides Induced by Water Vapor
No full textWith its high stability
and well-tuned binding strength for adsorbates,
platinum is an excellent catalyst for a wide range of reactions. In
applications like car exhaust purification, the oxidation of hydrocarbons,
and fuel cells, platinum is exposed to highly oxidizing conditions,
which often leads to the formation of surface oxides. To reveal the
structure of these surface oxides, the oxidation of Pt in O2 has been widely studied. However, in most applications, H2O is also an important or even dominant part of the reaction mixture.
Here, we investigate the interaction of H2O with Pt surface
oxides using near-ambient-pressure X-ray photoelectron spectroscopy.
We find that reversible hydroxylation readily occurs in H2O/O2 mixtures. Using time-resolved measurements, we show
that O–OH exchange occurs on a time scale of seconds
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
ChemInform Abstract: X‐Ray Photoelectron Spectroscopy for Investigation of Heterogeneous Catalytic Processes
No full textVariations 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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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