1,720,995 research outputs found
Investigation of crystal field, magnetic frustration and magnetization reversal effects in 4f and 3d oxides
Get PDFThis thesis deals with the investigation of single-ion excitations, magnetic frustration, and magnetization reversal phenomena. We have employed neutron scattering, μ+SR, and computational methods for these studies.
Inverse spinel oxide Co2VO4 belongs to the family of spinel vanadates where cobalt and vanadium ions occupy the spinel B-site equally. This system exhibits magnetization reversal for temperatures below 65 K. Magnetization studies reveal three anomalies involving collinear and non-collinear ferrimagnetism phase and magnetization reversal crossover. Neutron diffraction analysis of Co2VO4 unveils that the evolution of relative balance between the two sublattice moments leads to ferrimagnetic phase and magnetization reversal. DFT calculation and μ+SR results suggest delocalization -localization crossover as the underlying microscopic mechanism for magnetization reversal.
Rare earth oxide SrTm2O4 belongs to the family of SrLn2O4 where two inequivalent Tm3+s form two zig-zag chains along the orthorhombic c-axis. An earlier study on SrTm2O4 reports the absence of long- or short-range order down to 65 mK. The crystal fields and exchange interactions in SrTm2O4 were studied to examine the absence of order. The crystal fields in SrTm2O4 were modeled using DFT and the effective charge (EC) model. The EC model describes the system well and suggests ꞁJ,mj > = ꞁ6,0> dominates the ground state of both Tm3+s. The exchange interactions extracted from low-energy dispersing excitations using random phase approximation suggest that Tm2 chains are frustrated and Tm1 chains could form dimers. The critical ratio calculated from exchange interaction indicates SrTm2O4 cannot undergo a thermal second-order phase transition confirming the absence of order. μ+SR results show oscillations in polarization evolution spectra; these are typically associated with muon precession due to the system’s long-range order. Modeling precession frequency vs. temperature reveals that these oscillations originate due to nuclear hyperfine enhancement. Additionally, the magnetic field application induces long-range order, with Tm2 function as polarized paramagnet whereas Tm1 above 4 T transitions into XY-AFM phase
Magnetic structures of the lithium orthophosphates and the study of the Bragg glass phase of vortex matter
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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
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