1,721,283 research outputs found
The effect of exciton dimensionality on resonance energy transfer: advances for organic color converters in hybrid inorganic/organic LEDs
No full textThe dependence of resonance energy transfer from Wannier-Mott excitons to an organic overlayer on exciton dimensionality is studied experimentally and by means of supporting simulations. The variation of temperature effectively tunes the balance between localized and free excitons, and allows to investigate the effect of the excitonic potential disorder on resonance energy transfer. Our theoretical calculations give insight into the experimentally observed temperature dependence of resonance energy transfer, and allow us to quantify the contribution from localized and free excitons. It is shown that free excitons can undergo resonance energy transfer at a rate that is an order of magnitude higher compared to localized excitons. In planar geometries nonradiative resonance energy transfer is dominating over radiative energy transfer and hence we propose hybrid inorganic-organic LEDs which are optimized for resonance energy transfer to an organic or QD-based color converter
Dependence of resonance energy transfer on exciton dimensionality
Get PDFWe investigate the dependence of resonance energy transfer from Wannier-Mott excitons to an organic overlayer on exciton dimensionality. We exploit the excitonic potential disorder in a single quantum well to tune the balance between localized and free excitons by scaling the Boltzmann distribution of excitons through temperature. Theoretical calculations predict the experimentally observed temperature dependence of resonance energy transfer and allow us to quantify the contribution of localized and free excitons. We show that free excitons can undergo resonance energy transfer with an order of magnitude higher rate compared to localized excitons, emphasizing the potential of hybrid optoelectronic devices utilizing resonance energy transfer as a means to overcome charge transfer related limitations
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
SOI LEDs with carrier confinement
Get PDFSilicon-On-Insulator (SOI) technology exhibits significant performance advantages over conventional bulk silicon technology in both electronics and optoelectronics. In this chapter we present an overview of recent applications on light emission from SOI materials. Particularly, in our work we used SOI technology to fabricate light emitting diodes (LEDs), which emit around 1130 nm wavelength with an external quantum efficiency of 1.4 ﾗ 10−4 at room temperature (corresponding to an internal quantum efficiency close to 1 %). This is almost two orders of magnitude higher than reported earlier for SOI LEDs. This large improvement is due to three carrier confinement mechanisms: geometrical effects, quantum-size effects, and electric field effects. Our lateral p+/p/n+ structure is powered through two very thin silicon slabs adjacent to the p+/p and n+/p junction. Such use of thin silicon films aims to reduce the p+ and n+ contact area and to confine the injected carriers in the central lowly doped p-region. With this approach, we realized an efficient compact infrared light source with high potential switching speed for on-chip integration applications
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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