1,720,988 research outputs found
Advanced CVD technology for 2D materials: graphene and transition metal di-chalcogenides
No full textGraphene, one of the most important two dimensional (2D) materials, has been attracting increasing interest and new applications in nano-scale electronic and photonic applications through the unprecedented electronic and optical properties it offers. However, the zero bandgap of graphene has restricted its use in some optoelectronic applications. Recently, transition metal dichalcogenides (TMDCs), two-dimensional layered materials, such as MoS2, MoSe2, WS2 and WSe2 have become a noteworthy complimentary material to graphene sharing many of its properties. They may however offer properties that are unattainable in graphene since TMDCs offer tuneability allowing a bandgap transition from indirect to direct with the single layer. This has led to use of TMDCs in applications such as transistors, photodetectors and electroluminescent devices. Chemical vapour deposition (CVD) technology has the advantage of offering conformal, scalable, and controllable thin film growth on a variety of different substrates. In this talk we describe our recent development in 2D materials, in particularly graphene and TMDCs, by the CVD technology and discuss their potential applications
Fabrication of thin film solar cell materials by APCVD
No full textThin film solar cells are currently being implemented commercially as they reduce the amount of semiconductor material required for each cell when compared to silicon wafers, thereby lowering the cost of production. Currently two direct band gap chalcogenide thin-film technologies, CdTe and CuInGa(S,Se)2 (CIGS), yield the highest reported power conversion efficiencies of 16.5% and 20.3%, respectively. In addition, Cu2ZnSnS4 (CZTS) is one of the most promising chalcogenide thin film photovoltaic absorber materials; with an optimal band gap of about 1.5 eV. More importantly, CZTS consists of abundant and non-toxic elements, so research on CZTS thin-film solar cells has been increasing significantly in recent years. Moreover, Sb2S3 based chalcogenide thin films have been proposed for use in photovoltaic applications. The preparation of chalcogenide thin films solar cells commonly use physical vapour deposition methods including thermal/e-beam evaporation, sputtering, and pulsed laser deposition, electrochemical deposition, spray pyrolysis, solution-based synthesis, followed by the sulfurization or selenization annealing process. In this paper, we report a non-vacuum process, using atmospheric pressure chemical vapour deposition (APCVD), to fabricate chalcogenide thin film solar cell materials as well as transparent conductive oxide (TCO) thin films. The optical, electrical, and structural properties of these materials were characterized by UV-VIS-NIR, four-point probes, SEM, EDX, XRD, Micro-Raman
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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