1,720,956 research outputs found
Surface Gold Atoms Determine Peroxidase Mimic Activity in Gold Alloy Nanoparticles
Full text link: The development of peroxidase mimic nanocatalysts is relevant for oxidation reactions in biosensing, environmental monitoring and green chemical processes. Several nanomaterials have been proposed as peroxidase mimic, the majority of which consists of noble metals and oxide nanoparticles (NPs). Yet, there is still limited information about how the change in the composition influences their catalytic activity. Here, the peroxidase mimic behaviour of gold NPs is compared to a traditional nanoalloy as Au-Ag and to the Au-Fe and the Au-Co nanoalloys, which were not tested before as oxidation catalysts. Since the alloys of gold with iron and cobalt are thermodynamically unstable, laser ablation in liquid (LAL) is exploited for the synthesis of these NPs. Using LAL, no chemical stabilizers or capping agents are present on the NPs surface, allowing the evaluation of the oxidation behaviour as a function of the alloy composition. The results point to the importance of surface gold atoms in the catalytic process, but also indicate the possibility of obtaining active nanocatalysts with a lower content of Au by alloying it with iron, which is earth-abundant, non-toxic and low cost. Overall, Au nanoalloys are worth consideration as a more sustainable alternative to pure Au nanocatalysts for oxidation reactions
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
Hyperdoping of Epitaxial Ge:P Layers by UV Nanosecond Laser Processing
No full textopenThis thesis investigates the potential of Pulsed Laser Melting (PLM) for achieving efficient n-type hyperdoping in epitaxial Ge:P layers and for overcoming the activation limits of conventional doping techniques. Epitaxial Ge:P wafers grown by Low Energy Plasma Enhanced Chemical Vapor Deposition (LEPECVD) were processed by nanosecond ultraviolet laser pulses at varying energy densities and, in selected cases, subjected to Rapid Thermal Processing (RTP) to assess the thermal stability of the metastable hyperdoped layers. The structural, electrical, and optical properties of the processed samples were analyzed through Secondary Ion Mass Spectrometry (SIMS), Van der Pauw–Hall measurements, Fourier-transform infrared spectroscopy, Atomic Force Microscopy (AFM), and Conductive Atomic Force Microscopy (C-AFM). The results demonstrate that PLM enables active dopant concentrations far exceeding the solid solubility limit, while preserving the crystalline quality and surface morphology of the epitaxial layers. Electrical characterization revealed activation fractions up to ~80% of the incorporated phosphorus, representing a substantial improvement over as-grown conditions. Thermal stability studies indicated a rapid deactivation of dopants above 175 °C, highlighting the necessity of low-thermal-budget integration strategies. Furthermore, a depth-resolved characterization methodology based on C-AFM was developed and validated, enabling nanoscale profiling of active dopant distributions in beveled cross-sections. The technique exhibited excellent agreement with SIMS data, establishing C-AFM as a powerful complement to conventional electrical characterization. Overall, this work confirms the effectiveness of PLM for controlled hyperdoping of germanium and introduces a novel methodology for high-resolution depth-resolved dopant activation analysis, paving the way for the integration of hyperdoped Ge:P layers into advanced photonic and electronic devices.This thesis investigates the potential of Pulsed Laser Melting (PLM) for achieving efficient n-type hyperdoping in epitaxial Ge:P layers and for overcoming the activation limits of conventional doping techniques. Epitaxial Ge:P wafers grown by Low Energy Plasma Enhanced Chemical Vapor Deposition (LEPECVD) were processed by nanosecond ultraviolet laser pulses at varying energy densities and, in selected cases, subjected to Rapid Thermal Processing (RTP) to assess the thermal stability of the metastable hyperdoped layers. The structural, electrical, and optical properties of the processed samples were analyzed through Secondary Ion Mass Spectrometry (SIMS), Van der Pauw–Hall measurements, Fourier-transform infrared spectroscopy, Atomic Force Microscopy (AFM), and Conductive Atomic Force Microscopy (C-AFM). The results demonstrate that PLM enables active dopant concentrations far exceeding the solid solubility limit, while preserving the crystalline quality and surface morphology of the epitaxial layers. Electrical characterization revealed activation fractions up to ~80% of the incorporated phosphorus, representing a substantial improvement over as-grown conditions. Thermal stability studies indicated a rapid deactivation of dopants above 175 °C, highlighting the necessity of low-thermal-budget integration strategies. Furthermore, a depth-resolved characterization methodology based on C-AFM was developed and validated, enabling nanoscale profiling of active dopant distributions in beveled cross-sections. The technique exhibited excellent agreement with SIMS data, establishing C-AFM as a powerful complement to conventional electrical characterization. Overall, this work confirms the effectiveness of PLM for controlled hyperdoping of germanium and introduces a novel methodology for high-resolution depth-resolved dopant activation analysis, paving the way for the integration of hyperdoped Ge:P layers into advanced photonic and electronic devices
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
Ex-situ incorporation of Al in Ge by sputter deposition and pulsed laser melting: a new approach to fabricate hyper-doped Ge:Al alloys
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