1,721,050 research outputs found
Hydrogen interaction with Al(111) and Ti-doped Al(111) surfaces for H storage applications
No full textComplex metal hydrides are promising candidates for hydrogen storage applications.
Most of these materials consist of aluminum mixed with other elements. It was found
that titanium doping allows their use in a convenient temperature and pressure range.
Therefore the key process is the dissociation of molecular hydrogen at a Ti catalyst on the surface. Preliminary studies with pure and titanium-doped aluminum surfaces are
undertaken to gain a basic understanding of the hydrogen adsorption mechanism.
The interaction of hydrogen with an Al(111) surface was studied using Infrared Reflection
Absorption Spectroscopy (IRRAS) under Ultra High Vacuum (UHV) conditions. Hereby the formation of aluminum hydrides (alanes) in different sizes was observed depending on the hydrogen coverage of the surface. The growth of larger alanes is favored at higher H exposures. Different measurements were carried out for temperatures of 93, 180 and 259K and it was found that larger alanes form at higher temperatures.
In another step of the experiment an Al surface was doped with titanium atoms emitted from a home-built Ti-source. Ti structures with a thickness of less than one monolayer (ML) were grown at 105K and a Ti film of around one ML was deposited at room temperature. The deposition rate was determined with a quartz crystal monitor and the deposition on the surface could be verified by Auger Electron Spectroscopy (AES). Low Energy Electron Diffraction (LEED) patterns were recorded before and after different Ti-depositions and were always showing the typical hexagonal symmetry for the closed packed (111) surface of the fcc Al crystal.
To compare the vibrational modes of alanes forming on Al(111) surfaces with the ones of solid state AlH3 Fourier Transform Infrared Spectroscopy (FTIR) was performed in a different setup using a high vacuum. No matches of the frequencies could be found but the decomposition of AlH3 to Al and H could be observed at temperatures higher than 170°C.M.S.Includes bibliographical references (p. 74-76)
New extended interpolating fields built from three-dimensional fermions
Full text linkNew extended interpolating operators made of quenched three dimensional fermions are introduced in the context of lattice QCD. The mass of the 3D fermions can be tuned in a controlled way to find a better overlap of the extended operators with the states of interest. The extended operators have good renormalization properties and are easy to control when taking the continuum limit. Moreover the short distance behaviour of the two point functions built from these operators is greatly improved. A numerical comparison with point sources and Jacobi smeared sources on dynamical 2+1 flavour configurations is presented
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
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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