1,720,956 research outputs found
Bias-controlled catalytic selectivity via metal-semiconductor schottky nanodiodes
No full textThe selective oxidation of methanol serves as a model reaction for probing the fundamental principles of heterogeneous catalysis, where control over product distribution remains a central challenge. Here, we report a catalytic nanodiode platform based on a Pt/n-type TiO2 Schottky junction that enables active modulation of reaction selectivity via applied electrical bias. By systematically varying the bias direction and magnitude during methanol oxidation under oxygen-rich conditions, we demonstrate that accumulation of negative charge on the Pt surface under reverse bias leads to a consistent decrease in methyl formate selectivity, indicating a shift toward full oxidation pathways. Electrical measurements confirm the suppression of current under reverse bias, supporting the formation of an electron-rich catalytic interface. These results provide direct experimental evidence that external control of interfacial charge can influence reaction selectivity, establishing catalytic nano-diodes as a promising platform for electronically tunable heterogeneous catalysis.
Electronic Switching between Hot Electrons and Hot Holes via Schottky Junctions during Chemical Reactions
No full textHot carriers, generated through nonadiabatic energy dissipation during exothermic catalytic reactions, play a pivotal role in enhancing catalytic performance. Upon generation, hot electrons typically reside in the sp-band above the Fermi level, while hot holes are formed in the d-band below the Fermi level, following the energy distribution of the metal's electronic structure. However, it has been technically challenging to simultaneously capture and understand the flow of these two opposite charges during chemical reactions. In this study, we employed Pt/Si Schottky nanodiodes to detect reaction-induced hot carriers. The flux of hot electrons and hot holes was observed to vary depending on whether the Pt catalyst was deposited on n-Si or p-Si, respectively. Indeed, the detection probability of hot holes was lower compared to hot electrons, attributed to the shorter mean free path of hot holes. This demonstrates that for quantitative capture of hot carriers at the metal-semiconductor Schottky junction, the transport process through which the excited carrier passes the metal must also be considered. When a forward bias was applied to the Pt/p-Si nanodiode, a switch from hot hole to hot electron transfer was observed, due to the perturbation of the band structures. Our first prototype platforms, which self-control the transfer of hot carriers during the chemical reaction using Schottky junctions, may offer insights into potential applications of hot carriers in catalytic devices, energy conversion-based devices, or chemical sensors.
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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