1,720,957 research outputs found
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
New Classes of III-Nitrides for Light Emitters and Power Electronics
No full textIII-nitride semiconductors have achieved great success in wide ranging applications including solid-state lighting, power electronics, photovoltaic, biosensing, etc. III-nitride semiconductors refer to the compound semiconductors that formed by group III elements (including Gallium, Aluminum, and Indium) with Nitrogen. The III-nitride material system allows bandgap engineering from 0.7 eV up to 6.2 eV, which enables emission covering the entire visible spectrum as well as deep ultraviolet (UV) and infrared regions for III-nitride-based light emitters. The wide bandgap capability of III-nitride materials also results in higher voltage, higher operation temperatures, higher switching frequency, and higher power figure of merit (FOM) for power electronic devices, in comparison to Si-based devices. However, there are several challenges in III-nitride material system that may hinder the performance of devices, which need to be addressed: 1) charge separation (caused by large polarization fields in III-nitride materials), 2) high dislocation density (induced by lattice-mismatch), 3) Indium-phase separation. Thus, further improvements are required to enhance the performance III-nitride-based devices for light emitters and power electronics. In this work, we investigate solutions provided by new classes of III-nitride materials that may address the challenges for the traditional III-nitride material system. We study opportunities in new classes of III-nitrides, including ZnGeN2, dilute-As InGaNAs, and ScAlN for light emitters and power electronics. We simulate type-II AlInN / ZnGeN2 quantum well (QW) structures serving as active regions that significantly reduce threshold current density for ultraviolet (UV) laser diodes. We investigate the band alignment of dilute-As InGaNAs/GaN heterojunctions and present a staggered dilute-As InGaNAs-based quantum well active region design for high-efficiency red laser diodes. We calculate the fundamental properties of ScAlN alloys, such as band structure, electron mobility, power figure of merit (FOM), and band alignment with respect to GaN. A power FOM of ~62.6-87.3 GW/cm2 is calculated from lattice-matched Sc0.18Al0.82N, which is ~5-7 and ~ 8-11 times larger than those of GaN and SiC, respectively. Our findings suggest Sc0.18Al0.82N possesses large breakdown voltage and low specific on-resistance, which indicate the great potential for Sc0.18Al0.82N to be implemented in high-voltage power electronics for improved device performance. In addition, we study the properties of AlGaInN alloys that are lattice-matched to GaN. We successfully perform the epitaxial growth of lattice-matched AlGaInN alloys with good crystalline and smooth surface morphology via metalorganic chemical vapor deposition (MOCVD). We investigate the refractive index of lattice-matched AlGaInN alloys by ellipsometry measurements. We show the simulation results of InGaN/GaN quantum wells with AlGaInN barriers, where we obtain significant reduction in threshold current density for laser diodes. We successfully grow the InGaN/GaN multiple quantum wells (MQWs) and InGaN/AlGaInN MQWs via MOCVD and characterize the MQWs with X-ray diffraction (XRD). The InGaN/AlGaInN MQWs show 25% photoluminescence enhancement compared to the conventional InGaN/GaN MQWs. The research works presented in this dissertation provided insights into incorporating new classes of III-nitrides to enhance the performance of III-nitride devices, which may serve to be essential for the development of next generation III-nitride lighter emitters and power electronics
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
Analysis of InGaN Quantum Wells with AlGaInN Barriers
No full textAbstractVarious strain-compensated InGaN-AlGaInN quantum well (QW) structures are investigated by self-consistent 6-band k∙p method, which considers valence band mixing, the strain effect, spontaneous and piezoelectric polarizations and the carrier screening effect, for their spontaneous emission and gain properties. The InGaN QW with In-content of 28% is sandwiched by AlGaInN barriers, which are Al0.2Ga0.8N, Al0.56Ga0.32In0.12N, Al0.72Ga0.13In0.15N, Al0.78Ga0.1In0.12N, and Al0.82Ga0.1In0.08N, with corresponding band gaps of 3.821eV, 4.156eV, 4.465eV, 4.765eV, and 5.065eV, respectively. Both the spontaneous emission spectra and optical gain properties of strain-compensated InGaN–AlGaInN QWs reveal enhancement in comparison to those of conventional InGaN–GN QWs. The enhancement factors of spontaneous emission spectra and peak gain properties for different barrier structures are found to follow a parabolic trend. This indicates differing amounts of improvement of the radiative efficiency for light emitting diodes. This study shows that there is an optimized composition for an AlGaInN barrier layer surrounding an In0.28Ga0.72N quantum well between the bandgaps of 4.156eV and 4.465eV that will obtain the highest spontaneous emission rate and gain properties
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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