1,721,038 research outputs found
Photoionization experiments in the study of energy transfer in nanostructured materials and their precursors
No full textThis thesis deals with the study of the electronic structure of substances relevant to molecular materials technology. Detailed investigations were carried out by means of core and valence photoionization spectroscopy supported by Density Functional Theory (DFT) calculations. An approach similar to the “bottom-up” strategy was adopted, starting from the study of the simpler molecular building blocks as model systems and increasing complexity to larger molecular systems and deposited films.
In the first part, three simple organic system where characterized in detail:oligothiohenes, biphenylene and pyridines. A systematic study of oligothiophenes was performed as a function of the chain length. The evolution of the spectral features is analyzed as a function of the number of thiophene rings; a tendency to a stabilization for increasing chain length is found. Theoretical computation assisted in the assignment the spectral features to the different carbon sites. For biphenylene, the characters of the non-equivalent carbons were separated in gas phase core hole spectra. In a film, the adsorbed biphenylene is characterized by important intermolecular interactions but maintains, substantially, a molecular character. The molecules choose an ordered arrangement and switch their orientation from lying to standing on the surface for increasing coverage. In the study of pyridines and fluorinated derivatives the contributions of molecular vibrations was been added in the analysis and simulation of the experiments. This study is particularly appealing in view of the sufficient reliability and low computational cost of our computational protocol.
The second part is dedicated to Transition Metal Phthalocyanines (Pc), which are systems of higher complexity than the previous ones. They are widely studied for the possibility to deposit them in molecular films suitable for a variety of technological applications. Fe and Mn Pc’s were chosen since the different metal in the molecular center gives rise to Highest Occupied Molecular orbitals (HOMO) with different atomic characters. Our analysis reveals that the electronic structure of the Pc molecules rises from the combination of orbitals of all the atoms in the molecule - carbon, nitrogen and the metal in the molecular center - and that the HOMO and HOMO-1 features depend on the hybridization between the metal atom and mostly C 2p and N 2p orbitals.
In the third part, a parallel research activity towards the development of novel light sources in view of their application for time resolved photoionization studies of energy transfer processes in novel materials. CITIUS, a new light source for ultrafast science is presented. CITIUS provides tunable, intense, femtosecond pulses in the spectral range from infrared to extreme ultraviolet (XUV). The generated pulses are produced by laser induced high order harmonic generation (HHG) in gas and then monochromatized by a time preserving monochromator. We present the results of two pump-probe experiments: one to characterize the temporal duration of harmonic pulses; the second one to demonstrate the capability for selective investigation of the ultrafast dynamics in a magnetic compound. Secondarily, the Low Density Matter (LDM) beamline of the FERMI free electron laser (FEL) is described. LDM was designed for experiments with supersonic beams of atoms, molecules or clusters to explore nonlinear multiple ionization processes and energy redistribution processes after photoexcitation. The LDM beamline is ideal for performing experiments over a broad range of topics (e.g. photofragmentation or even ultrafast demagnetization) because of its ability to take advantage of the full control of the FEL pulse polarization. The design and characterization of the LDM photon transport system is described, detailing the optical components of the beamline
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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