1,721,159 research outputs found
White light-emitting LED using electrospun Alq3/P3BT composite microfibers
No full textWe prepared a white light-emitting LED by electrospinning small organic molecules (Alq3) and polymer (P3BT) composite microfibers directly onto a blue LED. The formation of the composite microfiber was optically characterized using the photoluminescence and Raman spectroscopy at the single strand level. We found that the 23:1 weight ratio of Alq3 and P3BT produced optimized white emission when combined with the intrinsic blue emission from the LED due to the fluorescence resonance energy transfer from the Alq3 to the P3BT. The environmentally friendly Alq3/P3BT organic composite microfibers efficiently demonstrated the photo conversion of blue LED into pure white LED. © 2014 Elsevier B.V.1561sciescopu
Supplementary_material – Supplemental material for Performance group weighting factors for rapid seismic loss estimation of buildings of different usage
No full textSupplemental material, Supplementary_material for Performance group weighting factors for rapid seismic loss estimation of buildings of different usage by Shreedhar Khakurel, Rajesh P Dhakal, Trevor Z Yeow and Sandip K Saha in Earthquake Spectra</p
Heterogeneous modulation of exciton emission in triangular WS2 monolayers by chemical treatment
No full textChemical treatments were recently shown to be very effective in enhancing the exciton emission of monolayer transition metal dichalcogenides (1L-TMDs) by suppressing the exciton quenching caused by structural defects. However, the effects of these chemical treatments varied greatly depending on the synthesis method and the type of 1L-TMD; therefore, the exact origin of the emission enhancement is still elusive. Here we report the spatially heterogeneous effects of bis(trifluoromethane) sulfonimide (TFSI) and benzyl viologen (BV) treatment on the optical properties of triangular 1L-WS2 grown by chemical vapor deposition (CVD). Nanoscale photoluminescence (PL) and Raman spectral maps showed that TFSI had a minimal effect on the inner region of the triangular WS2 grain, whereas the PL of the edge region was enhanced up to 25 times; further, BV reduced the PL, also more strikingly in the edge region. Systematic variation of the spectral weights among neutral excitons, trions, and bi-excitons indicated that p-doping and n-doping with TFSI and BV, respectively, occurred in both the inner and edge regions; however, the PL enhancement was attributed mainly to the reduction of structural defects caused by TFSI treatment. Our observation of the spatially heterogeneous effects of chemical treatment suggests that the inner and edge regions of CVD-grown 1L-WS2 are populated with different types of structural defects and helps in clarifying the mechanism by which chemical treatment enhances the optical properties of 1L-TMDs. This journal is ©The Royal Society of Chemistry 20176
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
Gold nanoparticle hybridized rubrene nanofibers made by electrospinning: enhancement of optical and structural properties
No full textWe prepared gold nanoparticle (Au NP) hybridized organic rubrene nanofibers (NFs) using a convenient
electrospinning method. Au NPs of size 2–3 nm were incorporated throughout the light emitting
rubrene NFs, which was confirmed by high resolution transmission electron microscopy. Au NP
hybridized rubrene NFs showed a distinct nanoporous surface, compared to the smooth surface of
rubrene NFs. Nanoscale confocal spectroscopy was performed on a single NF level and the results
showed that the photoluminescence (PL) of the hybrid NFs made with 15 wt% Au NP mixture solution
was 2.5 times higher than the PL of the rubrene NFs. And the optical extinction (scattering and
absorption) of hybrid NFs increased monotonically with increasing Au NP concentrations. These
enhanced optical properties of hybrid NFs were attributed to localized surface plasmon resonance of the
embedded Au NPs. Structural modification from the monoclinic phase to the orthorhombic phase of the
rubrene structure was obtained by XRD analysis indicating a better ordering along the rubrene ab plane
of the hybrid NFs.1441sciescopu
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
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