1,720,953 research outputs found
Magnetoelectric Effect in Lead-Free Multiferroic Composites and Thin Films
Full text linkThe functional behavior of two-phase composites consisting of piezoelectric and magnetostrictive components is a manifestation of the coupled nature of their constituent phases, known as magnetoelectric (ME) effect. It has a promise in it to a progress in the modern electronic industry by not only improving the existing properties but also reducing the size of microelectronic components. However, the demand for miniaturization has not seized because it is now accompanied by the demand of environment-friendly materials.
Therefore, the primary aims of this dissertation are to develop new lead-free multiferroic materials and to study the relationship between the intrinsic properties of piezoelectric and magnetostrictive components and the resulting ME coupling between them. The
ferroelectric component with excellent piezoelectric properties combined with the component with excellent magnetostrictive properties would lead to enhanced ME coupling and value-added understanding of the science behind it.
At first, a piezoelectric composition in the system of (1-x)(Ba,Ca)TiO3 -xBa(Zr,Ti)O3 with x = 0.5 was identified (BCT50-BZT) with piezoelectric coefficient of value greater than 500 pC/N in order to utilize it as the piezoelectric phase. The converse ME coefficient of 0.5(Ba,Ca)TiO3 - 0.5Ba(Zr,Ti)O3-15% CoFe2O4 was found to be around 6 ps/m.
It was discovered that the constituent electromechanical coupling factor and magnetomechanical coupling factor might play a role on the ME response. To understand the role of magnetostrictive phase, it was modified with a non-magnetic Al3+ ion. The composite
of 0.5(Ba,Ca)TiO3 - 0.5Ba(Zr,Ti)O3 - 50% Co(Fe1.5Al0.5O4 was found to possess 3-times larger converse ME coefficient compared to its unmodified counterpart. This enhancement was attributed to the improved effective piezomagnetic coefficient d/dH and increased
initial permeability of the Al3+ modified CFO.
Secondly, using the knowledge from the BCZT-CFO composites, NiFe2O4 (NFO) was introduced as the magnetostrictive phase which has initial magnetic permeability of 39 that is much larger than that of CFO. This provided an enhancement of around 400 % in the ME coupling in BCZT-30%NFO (converse ME coefficient of 45 ps/m) sample
as compared with that of BCZT-50%CFO(Al) (11 ps/m). Hence it gave a substantial evidence that the most important properties to be considered to improve the ME response of two-phase composites are the initial magnetic permeability of the ferrite phase and the
maximal elastic compliance of the piezoelectric phase. This discovery has a potential to open new horizons for tailoring of new ME materials.
Thirdly, a two-phase system consisting of relaxor ferroelectric Ba(Ti, Sn)O3 combined with CFO was studied. This system is a unique example of two-phase systems in which the dielectric properties were almost entirely retained even in the composite, which is in contrast to the case in other non-relaxor-magnetostrictive composites reported here. The ME coupling of the composite consisting of Ba(Ti0.7Sn0.3)O3-20%CFO was much better than the normal ferroelectric-magnetostrictive composites studied for their magnetodielectric properties, previously. The correlation of the maximum of elastic compliance versus temperature and the induced ME versus temperature curves was highlighted, providing
another evidence of the vital role electromechanical softness of the ferroelectric material on the stress/strain mediated ME coupling.
Lastly, when the connectivity was changed from (0-3) to (2-2) which is a bilayer geometry, improved local direct ME coupling was observed, due to the better interface between the magnetostrictive phase and the ferroelectric phase. Bilayered thin films of CFO and BaTiO3 (BTO) were synthesized with pulsed laser deposition on two differently
oriented substrates. TEM analyses revealed that the CFO layer had a better interface when it was grown on (111) oriented substrate in comparison to that of (100) oriented substrate. This is a discovery as there are no reports in literature on the growth bilayered
thin films on (111) oriented substrate. Direct ME coupling studied with PFM under an applied dc magnetic field. The bilayered thin film on (111) oriented substrate has an improved ME coupling in comparison to that of bilayered thin film grown on the (100) oriented substrate
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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