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Magnetic Moments of Free, Size-Selected Iron, Cobalt, and Nickel Clusters
No full textIn dieser Arbeit wurde erfolgreich ein Experiment zur Messung Spin-Bahn aufgelöster magnetischer Momente von freien, massenselektierten Clustern mittels XMCD-Spekroskopie aufgebaut. Erste Messungen an kationischen Eisen-, Cobalt- und Nickelclustern im mittleren Größenbereich (Fe+10−15, Co+10−15, Ni+10−15) zeigen, dass diese Cluster anders als im Festkörper starke Ferromagneten mit vollständig gefülltem Majoritätsband und maximalen Spinmomenten von μs = 1.0 μB pro 3d Loch sind, was durch die geringe Koordination der Atome in Clustern verursacht wird. Als Ausnahme wird bei Fe+13 ein um 1.0 ± 0.4 μB pro Atom reduziertes Spinmoment beobachtet, was im Zusammenhang mit der hohen Symmetrie der Ikosaederstruktur steht. Bei sehr kleinen Clustern (Fe+2−6 und Co+2−6) kommt es vermutlich in Folge reduzierter mittlerer Bindungslängen zu unvollständig gefüllten Majoritätsbändern und verringerten Spinmomenten von μs < 1.0 μB pro 3d Loch. Die magnetischen Bahnmomente von Clustern sind im Vergleich zu Atomen bereits für sehr kleine Eisencluster stark reduziert und erreichen nur 5-25% des atomaren Wertes. Verursacht wird dies durch die Aufhebung der sphärischen Symmetrie im Kristallfeld benachbarter Atome. Bei kleinen Cobaltclustern wie Co+3 entsprechen die Bahnmomente dagegen bis zu 43% des atomaren Wertes und sind bis zur Clustergröße n ≤ 6 im Vergleich zu Eisenclustern systematisch erhöht. Ein Vergleich berechneter Spinmomente zeigt eine gute Übereinstimmung zwischen Theorie und Experiment für Eisencluster, aber eine systematische Diskrepanz für Cobalt- und Nickelcluster, wo Rechnungen die hier gemessenen Spinmomente im Durchschnitt um circa 0.5μB pro Atom unterschätzen. Die Ergebnisse von Stern-Gerlach Experimenten sind im Vergleich zu den hier gemessenen Gesamtmomenten für Eisen-, Cobalt- und Nickelcluster durchschnittlich um 0.5 μB verringert, was vermutlich durch eine unzureichende Thermalisierung der Cluster in den Stern-Gerlach Experimenten verursacht wird.In this work, an experiment for measuring spin and orbital resolved magnetic moments of free, mass selected clusters by means of XMCD-spectroscopy has been set up. First results on medium sized, cationic iron-, cobalt-, and nickel clusters (Fe+10−15, Co+10−15, Ni+10−15) show that in contrast to the bulk these clusters are strong ferromagnets with a completely filled majority spin band and a maximum spin moment of μs = 1.0 μB per 3d hole, that is induced by the low coordinated atoms of the clusters. As an exception, Fe+13 has a reduced spin moment of about 1.0 ± 0.4 μB per atom, that is related to the highly symmetric, icosahedral structure of Fe+13. For small clusters, majority spin bands are not saturated leading to reduced spin moments of μs < 1.0μB per 3d hole as a consequence of shrunken average nearest neighbour distances. A comparison of magnetic orbital moments of clusters and atoms reveals that already for small iron clusters, orbital moments are strongly reduced to 5-25% of its atomic value, induced by the breakup of spherical symmetry in the crystal field of nearby atoms. In contrast to iron clusters, orbital moments of small cobalt clusters like Co+3 correspond to up to 43% of the atomic value and a systematic enhancement compared to iron clusters is observed for clustersizes n ≤ 6. Calculations of spin moments of iron clusters achieve a good agreement between theory and experiment. For cobalt and nickel clusters, theory systematically underestimates the measured spin magnetic moments by about 0.5 μB per atom. Results from Stern-Gerlach deflection experiments are compared to our derived total magnetic momentes of iron, cobalt, and nickel clusters reduced by 0.5 μB per atom, that might be caused by an insufficient thermalization of the clusters in Stern-Gerlach experiments
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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