1,354,283 research outputs found
Temperature-Dependent Electromagnetic Surface Wave Supported by Graphene-Loaded Indium Antimonide Planar Structure
No full textIn this study, the propagation characteristics of EM surface waves supported by the graphene-coated indium antimonide (InSb) planar waveguide have been investigated theoretically and numerically. The modeling of graphene has been performed by use of Kubo formalism whereas the relative permittivity of indium antimonide has been calculated using Drude’s model. The results for transverse electric (TE) and transverse magnetic (TM) polarized surface waves have been computed analytically and numerically. The major challenge is to model the atomically thick graphene sheet over the InSb grounded slab. To get the temperature-dependent characteristic equation for the electromagnetic surface waves, the surface current boundary conditions’ approach has been employed. The numerical results have been computed for both the TE and TM polarization states and reported that the TE does not support the propagation of surface waves. The dispersion relation, effective mode index, phase speed, propagation length, and field profile have been computed in Mathematica under TM polarization. The graphene and indium antimonide have been found active for low and high Terahertz regions, respectively. As temperature increases, the plasma frequency of the InSb increases due to this reason with the increase of temperature and the resonance frequency, leading to a shift in the dispersion curve. Moreover, with the increase of temperature, the effective wave number of transverse magnetic polarized surface waves also increases. Resultantly, the confinement of such surface waves supported by graphene-loaded InSb increases. It is shown that with the variation of temperature of indium antimonide, the surface waves propagating across the interface can be tuned in the Terahertz region and can be exploited for thermo-optical sensing, near-field communications waveguides, and graphene-based temperature sensor designing
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
An Arabic Optical Braille Recognition System
No full textTechnology has shown great promise in providing access to textual information for visually impaired people. Optical Braille Recognition (OBR) allows people with visual impairments to read volumes of typewritten documents with the help of flatbed scanners and OBR software. This project looks at developing a system to recognize an image of embossed Arabic Braille and then convert it to text. It particularly aims to build fully functional Optical Arabic Braille Recognition system. It has two main tasks, first is to recognize printed Braille cells, and second is to convert them to regular text. Converting Braille to text is not simply a one to one mapping, because one cell may represent one symbol (alphabet letter, digit, or special character), two or more symbols, or part of a symbol. Moreover, multiple cells may represent a single symbol
Variations on the Author
No full text“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
Hybrid Dyakonov Surface Waves at Uniaxial Crystal-Temperature-Sensitive Material Interfaces
No full textA theoretical investigation of the temperature-dependent hybrid surface waves guided by the uniaxial crystal-temperature-sensitive material (TSM) interface is carried out in the present study. The uniaxial crystal is realized as a metamaterial having a direction-dependent permittivity tensor, with the optical axis (OA) parallel to the interface. Indium antimonide (InSb) is characterized as TSM, and the temperature-dependent electromagnetic (EM) characteristics of InSb are modeled using the extended Drude model. Analytical and numerical calculations have been performed to obtain the characteristics equation for the temperature-dependent hybrid surface waves. The contour plot technique has been implemented in Mathematica for the computation of dispersion relation. The influence of the temperature and propagation angle on the dispersion curve, effective mode index, phase speed, and propagation length was analyzed. It is reported that the proposed interface supports the two types of surface waves (i.e., (i) pure Dyakonov surface waves (DSWs) for the temperature range (i.e., T∈200,240 K) and (ii) hybrid plasmons waves for the temperature range (i.e., T∈290,360 K)). The computed results can be used to design temperature-assisted optical waveguides, thermo-optical sensors, and chemical sensing/communication devices
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Modeling of graphene wrapped indium antimonide nanowire as thermo-optical waveguide
No full textIn this research work, the fiber modes supported by the graphene-wrapped indium antimonide nanowire have been examined theoretically. The indium antimonide (InSb) is a semiconductor material, which has temperature-sensitive optoelectronic properties. To model the nanowire of InSb, Drude's model has been used for better results. The Kubo's formalism based on the random phase approximation is used for the modeling of graphene. The impedance boundary conditions (IBCs) are used to compute the characteristic equations. The real and imaginary part of permittivity of InSb as function of THz frequency under different values of temperature has been computed. It is reported that the InSb shows the temperature dependent metal-insulator phase transition i.e., for temperature T ≤ 200 K it behaves as insulator and for T > 200 K it acts as metal. The numerical results for dispersion relation, propagation band, propagation losses, cut off frequency range, effective mode index and field profiles have been presented for insulator as well as metallic phase of InSb. Moreover, the impact of chemical potential, radius, and temperature on fiber mode characteristics has been analyzed. The computed numerical results can be applied for designing tunable temperature assisted nano waveguides, thermo-optical sensing probes, thermal imaging and near-field communication devices in THz frequency range
Characteristics of polaritonic interactions at chiral loaded temperature-sensitive material (TSM) interfaces
No full textPolaritonic interactions are pivotal in advancing sensing technologies, optical devices, and waveguides. This study presents a theoretical investigation into polaritonic interactions at the interface of chiral-loaded temperature-sensitive materials (TSMs). Indium antimonide (InSb), known for its temperature-dependent phase-transition optical properties, is utilized as the TSM. The electromagnetic (EM) behavior of InSb is described using the extended Drude model, while the isotropic chiral medium is characterized through coupled constitutive relations. By applying tangential boundary conditions for EM field continuity at the chiral-InSb interface, the dispersion relation governing hybrid polaritons is derived. Numerical computations performed in Wolfram Mathematica, utilizing the contour plot technique, reveal the dispersion characteristics, effective mode index, and field distributions under varying temperatures. The findings demonstrate the existence of two distinct polaritonic regimes: (i) hybrid polariton-phonon coupling at temperatures below 200 K, and (ii) hybrid polariton-plasmon coupling at temperatures exceeding 260 K. Additionally, the effects of chirality and temperature on the dispersion curves, effective mode indices, and field profiles are systematically analyzed. Results reveal that polaritonic surface modes can be dynamically tuned by manipulating external temperature and material chirality. These insights hold significant promise for the development of temperature-responsive terahertz-infrared sensors, enantiomeric detectors, thermo-optical surface waveguides, and near-field imaging systems
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
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