1,721,044 research outputs found
Effects of non-resonant intense laser, electric and magnetic fields on exciton binding energy and absorption spectra in the Gaussian double quantum well
No full textThe present study examines the impact of external fields, including electric, magnetic, and non-resonant high-frequency intense laser fields, on the binding energies of the heavy hole excitons and interband absorption in GaAs/AlxGa1-xAs\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} Gaussian-shaped double quantum well. The study also considers the role of structural parameters such as the well width and the well depth. The results obtained show that the geometrical shape of the structure and the applied external fields are very effective tools on the excitonic binding and excitonic absorption spectra. From the results obtained, it was observed that the band gap of semiconductor materials can be changed by changing the structure parameters along with the external fields in accordance with the purpose. This tunability enables the development of devices with optimized performance and new functionalities, driving innovation in various fields of technology
Non-resonant intense laser field and electric field effects on the optical characterization of Rosen-Morse quantum wells with different potential functions
No full textThe present study examines the electronic and optical properties of Rosen-Morse quantum wells, which exhibit hyperbolic and exponential potential profiles, subjected to intense laser fields and electric fields. Calculations are performed within the framework of the effective mass and parabolic band approximations. To determine the eigenvalues of electrons confined in these potentials, the diagonalization method was employed, utilizing orthonormal base functions that are solutions of an infinite square quantum well. To calculate the total absorption coefficient, including linear and nonlinear terms for transitions between the lowest two energy levels, a combination of the standard density matrix formalism and the perturbation expansion method was employed. Our results indicate that intense laser field is a valuable tool for controlling the confinement potential of low-dimensional systems, enabling the appropriate tuning of these systems. While the electric field applied only to symmetrical structures breaks the symmetry and causes the peaks in the absorption spectrum to shift to red, a blue shift of the absorption peaks was achieved with the combined effect of the selected geometric shapes of the quantum wells and the electric field. Therefore, it is hoped that the obtained results will provide important improvements in device applications with a suitable choice of both fields and structure parameters
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
The anisotropy effects on the shallow-donor impurity states and optical transitions in quantum dots
No full textIn this work, we theoretically investigate the anisotropy effects on impurity states
and optical transitions in quantum dots. In particular, we investigate the role of the impurity
position on the binding energy and optical response of the ellipsoidal quantum dots. Theoretical
calculations have been carried out using the effective mass approach. The results show
that the impurity binding energies and the optical transitions between the impurity states are
significantly affected by the impurity position and aspect ratio of the ellipsoidal quantum
dots. In general, we conclude that the anisotropy degree of quantum dots can be used as a
tunability parameter for the electronic structure and optical response of the systems based on
the quantum dots
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
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