1,720,965 research outputs found
Energy Storage materials Based On Iron Phosphate
No full textSeveral iron phosphates were synthesized by solution-based techniques and tested as cathodes in non aqueous lithium cells. The addition of phosphate ions to a solution of iron (II) produced crystalline Fe3(PO4)2. This material is easily oxidized by air to form an amorphous phase that is able to reversibly intercalate lithium. The amorphous compound was identified to be a mixture of FePO4 and Fe2O3. A new synthetic route was developed to prepare pure amorphous FePO4. Amorphous LiFePO4 was obtained by chemical lithiation of FePO4. The material was heated at 500°C under reducing atmosphere to obtain nano-crystalline LiFePO4. This latter material showed excellent electrochemical performance when used as cathode of lithium cells
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
Analysis and distribution of volatile gases from catalytic pyrolysis of Sulcis low-rank coal
Full text linkCatalytic pyrolysis of Sulcis low-rank coal over naturally occurring olivine, and home-made 15 wt%Ni/γ-Al2O3 catalyst was conducted for the upgrading of coal pyrolysis volatile gases in the temperature range ambient-900 °C under atmospheric pressure. Raw coal and mixtures of coal-additive (90:10 wt%) were slowly heated in temperature programmed mode using a laboratory-scale quartz furnace coupled in parallel to Fourier transform infrared (FTIR) spectrometer and GC chromatograph for quantitative analysis of flue gas. Coal pyrolysis with and without additives was also conducted by TG/DTG/DSC analysis at different heating rate (β = 15, 20, 30 °Cmin−1). DSC results clearly indicated some extra exothermic events during catalytic coal pyrolysis. Quantitative gaseous products distribution with temperature showed yields significantly and selectively improved with additives. Generally, more CO and CO2 were emitted under catalytic coal pyrolysis. Meanwhile, nickel catalyst exerted a marked positive effect on H2 yield overall in the temperature range 400–500 °C. The light hydrocarbons such as methane, ethane, propane and n-hexane substantially remaining unchanged, whereas a remarkable increase of emitted ethene was originated from catalytic pyrolysis. A deeper SO2 evolution was observed over olivine, whereas the N-containing compounds (NH3, NOx) were also modified in catalytic pyrolysis. Formaldehyde was also monitored, which represents a fragment originating from polycyclic aromatic side chains. Reaction kinetic study by a model-free isoconversional method indicated a complex multiple-step mechanism of coal pyrolysis, exception made for conversion values between 5% and 50% where a single-step reaction path was operating. The calculated average Ea and the pre-exponential factor were markedly reduced by the presence of additives. Meanwhile the compensation effect was also existing
Matrix removal by thermal fluorination in the graphite furnace atomic absorption analysis of high purity aluminum
No full textTrace Cd, Co, and Pb elements distribution during Sulcis coal pyrolysis: GFAAS determination with slurry sampling technique
No full textAppropriate 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
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