1,720,960 research outputs found
The role of composition and diameter in the crystal purity of InAsxP1−x nanowires
Full text linkTernary InAsxP1−x nanowires are widely considered promising building blocks for fundamental studies and applications in nano- and opto-electronics. However, it is admittedly challenging to maintain the necessary control over the crystal purity of nanowires. Furthermore, the crystal phase trends in ternary III–V nanowires remain generally unknown. In this work, we present wurtzite InAsxP1−x nanowires with different compositions x, ranging from 0 to 0.54, grown via chemical beam epitaxy on InP(111)B substrates using Au colloidal catalysts of different diameters. Transmission electron microscopy studies reveal that a pure wurtzite phase of the nanowires requires larger InAs fractions x for larger diameters of Au colloids (in particular, x = 0.36 for 20 nm diameter and x = 0.54 for 30 nm diameter Au colloids). We developed a model for the critical composition of thin vapor–liquid–solid III–V ternary nanowires xc corresponding to the transition from a polytypic structure at x < xc to a pure wurtzite structure at x > xc. For the InAsxP1−x material, the critical composition increases with the nanowire diameter, which explains our experimental findings. These results shed more light on the composition- and diameter-dependent polytypism, offering valuable insights for the design and crystal phase control of InAsxP1−x and other III–V ternary nanowires
Zincblende InAsxP1–x/InP Quantum Dot Nanowires for Telecom Wavelength Emission
Full text linkInAsxP1–x quantum dots (QDs) in InP nanowires (NWs) have been realized as a platform for emission at telecom wavelengths. These QDs are typically grown in NWs with the wurtzite crystal phase, but in this case, ultrathin diameters are required to achieve defect-free heterostructures, making the structures less robust. In this work, we demonstrate the growth of pure zincblende InAsxP1–x QDs in InP NWs, which enabled an increase in NW diameters to about 45 nm, achieved by employing Au-assisted vapor liquid solid growth in a chemical beam epitaxy system. We studied the growth of InP/InAsxP1–x heterostructures with different compositions to control the straight growth along the ⟨100⟩ direction and to tune the emission wavelength. Interestingly, we found that the growth mechanism for pure InAs QDs is different compared to that for InAsxP1–x alloy QDs. This allowed us to optimize different growth protocols to achieve straight growth of the final QD NWs. We successfully obtained the growth of InAsxP1–x QDs with a composition in the range of x = 0.24–1.00. By means of microphotoluminescence measurements, we demonstrate the tunability of the emission in dependence of the InAsxP1–x QD composition and morphology, remarkably observing an emission at the telecom O-band for a 10 nm thick QD with 80% of As content
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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