1,721,053 research outputs found
Graphene derived lanthanum carbide targets for the SPES ISOL facility
Full text linkGraphene derived lanthanum carbide targets for the SPES ISOL facility By:Corradetti, S (Corradetti, S.)[ 1 ] ; Carturan, SM (Carturan, S. M.)[ 1,2 ] ; Andrighetto, A (Andrighetto, A.)[ 1 ] ; Mariotto, G (Mariotto, G.)[ 3 ] ; Giarola, M (Giarola, M.)[ 3 ] ; Fabrizi, A (Fabrizi, A.)[ 4 ] ; Maddalena, A (Maddalena, A.)[ 5 ] ; Biasetto, L (Biasetto, L.)[ 1,4 ] CERAMICS INTERNATIONAL Volume: 43 Issue: 14 Pages: 10824-10831 DOI: 10.1016/j.ceramint.2017.05.106 Published: OCT 1 2017 View Journal Impact Abstract Lanthanum carbide based targets were produced as benchmark tests before the production of radioactive uranium carbide targets. Carbides possessing excess carbon and porosity seem to be the best candidates as target for the production of exotic beams in the SPES-ISOL facility. In addition, the capability of tailoring properties such as grains size and pores size represents a step ahead to improve the ions release efficiency. In this work, multilayered graphene was used as source of carbon for the production of LaC and the main physical properties of the produced targets were compared to standard LaCx produced using micrometric graphite. The main output of the work consisted in the reduced total porosity (28.8 vol% vs 47.8 vol%) and increased shrinkage (20.4 vol% vs 5.8 vol%) of the LaCx-Graphene samples compared to LaCx-Graphite ones. This result showed how graphene can be successfully employed as sintering aid for the sintering of carbides. Further studies are ongoing with UO2 as starting reagent for carburization within the project AUL-2013-16-176 "Study of the use of graphene as source of carbon for Uranium Carbide-Graphene nanocomposites production" now under conclusion at the European Commission DG Joint Research Centre - JRC
Raman Spectroscopy and In Situ XRD Probing of the Thermal Decomposition of Sb2Se3 Thin Films
Full text linkSb2Se3 thin films have received increasing interest for their applications in optoelectronics. However, technological intervention demands a material-specific understanding of the reactivity to different environments. Both thermal annealing and laser irradiation carried out in an ambient atmosphere are expected to induce changes in the pristine crystallographic phase of Sb2Se3, causing the creation of additional secondary phases. Here, we investigate by means of Raman spectroscopy the effect of thermal annealing and laser irradiation at different fluencies on the structural and vibrational properties of Sb2Se3 thin films. The vacuum-annealed Sb2Se3 thin films at 290 °C and subjected to laser excitation power above 2 mW exhibit a secondary phase, revealing the occurrence of selenization. Further,in situX-ray diffraction over a broad range of annealing temperatures in N2and ambient atmospheres was employed to study the structural properties of the Sb2Se3thin films.In situXRD performed in a N2atmosphere does not show the formation of the Sb2O3cubic phase upon annealing until 500 °C. Conversely, a thermally activated systematic crystallization was observed upon annealing in an ambient atmosphere with the formation of the Sb2O3phase in the temperature range between 280 and 420 °C, until the complete decomposition of the material at 500 °C. Further, the orientation of vertically stacked (hk1) planes remains unchanged under a N2atmosphere, while horizontally stacked (hk0) planes dominate the (hk1) planes under ambient atmospheres
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
Straightforward identification of monolayer WS2 structures by Raman spectroscopy
No full textTungsten disulfide (WS2) is a very promising material with great potential for optoelectronics applications. To grow WS2 monolayer samples, chemical vapor deposition (CVD) is very reliable when it comes to controlling the sample quality, but there is still a lot of debate on whether the method is controllable beyond research-only systems. Although monolayer crystals are prepared through CVD, the challenge is to efficiently characterize and differentiate monolayer crystals from bilayers and few-layers. In this work, we report a new straightforward Raman peak identification to discriminate monolayer WS2 crystals from layered and bulk samples. Our method is based on the A1g peak behavior. We show that through the comparison and analysis of other less convenient techniques that the strong splitting in A1g mode in close-to-resonance excitation energy condition is a much more convenient and fast identification method than either low-wavenumber Raman scattering characterization or atomic force microscopy
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
Electric field-assisted ion exchange strengthening of borosilicate and soda lime silicate glass
Full text linkIn this study, we investigate the effects of electric field-assisted ion exchange (EF-IE) on potassium for sodium ion exchanges of soda borosilicate and soda lime silicate glasses. The results show that applying an electric field (E-field) with the intensity of 1000 V cm-1 for few minutes produces an exchanged layer with a thickness comparable to the conventional chemical strengthening for 4 hours. There is a critical E-field that increases the mobility and, therefore, the diffusion coefficient of the potassium ions in the glasses. The increase is, perhaps, related to the evolution of the glass structure due to the penetration of potassium ions under an E-field. Vickers indentations showed that strong compression is generated in the glass by EF-IE; however, the bending strength improvement is limited because of the presence of large surface defects and the stress distribution inhomogeneit
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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