1,720,979 research outputs found
Investigation of synthetic strategies for enhancing the energy product of spinel ferrite nanoparticles
Full text linkThis work was focused on the development of synthesis strategies for enhancing the energy product of spinel ferrite nanoparticles. The final goal was that of finding the best conditions to realize novel materials with improved magnetic properties, which could be used as building blocks for the realization of rare earth free - permanent magnet with higher energy products than commercial ferrites (i.e. strontium ferrite). To this aim, we focused on quasi-zero-dimensional magnetic materials and as possible strategies to enhance their performances we explored the coupling at the nanoscale with magnetic components endowed with complementary properties, and the modification of the intrinsic core properties by solvent mediated post-synthetic treatment.
In the first part of this work, hybrid nanocomposite magnets were designed, where the effective exchange-coupling through the interface between hard and soft magnetic constituents or between AFM and a F(i)M phases is exploited to increase the energy product of the material. In particular, metal/ferrite nano-heterostructures, NHSs, were synthesized by an optimized one-pot thermal decomposition method, which allowed us to tune the composition of the final product by tuning the synthetic parameters. The best NHSs obtained by this approach had energy product of 19 kJm-3, higher than that of the commercial hexagonal ferrite. With the aim of developing a system able to display exchange bias at room temperature, iron oxide AFM|FiM core|shell (CS) NPs doped with two divalent cations (Co(II) and Ni(II)) were also synthetized. The co-doping with cobalt and nickel revealed to be a good compromise for obtaining nanocrystals stable to further oxidation processes, and with increased anisotropy, bias and Néel temperature (260 K) than the standard CS iron oxide NPs.
The second part of the thesis was devoted to the improvement of the magnetic performances of the prepared CS AFM|F(i)M hybrid NPs and of standard cobalt ferrites NPs, by solvent mediated post-synthesis treatments. In the first case a mild oxidation of the Fe0.95O|Fe3O4, Co0.3Fe0.7O|Co0.8Fe2.2O4 and Ni0.17Co0.21Fe0.62O|Ni0.4Co0.3Fe2.3O4 CS NPs was realized by solvent mediated annealing in the presence of air, with the aim of investigating the role of the nature of the divalent ions on the structure and room temperature magnetic behaviour of the oxidized product. The Ni(II) and Co(II) amount during the oxidation process was found to play a crucial role in the formation of crystalline antiphase boundaries, leading to a mosaic texturing of the spinel structure in the NPs, characterized by enhanced exchange bias and high field magnetization with respect to the standard AFM|F(i)M NPs. The second investigated approach was the solvent mediated annealing treatment of standard cobalt ferrites NPs. This approach has proven to be an excellent strategy for increasing of the 48 % the BHmax value of the material thanks to the reduction of the lattice microstrain generated during the crystallites’ growth. The presented results provide indications on the validity of the proposed approaches. A further investigation is required to obtain materials characterized by exchange effect at room temperatures through a synthesis that can be carried out on a large scale
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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