1,721,031 research outputs found
Synthesis and characterisation of inorganic pigments
No full textInorganic materials, with potential application as pigments, have been synthesised in a wide range of phosphate, silicate, titanate and zeolitic systems and characterised in terms of their structure and physical properties using powder x-ray and powder neutron diffraction (PXD, PND), EXAFS, UV visible spectroscopy, colour measurements electron microscopy and thermal analysis.Complex cobalt phosphate materials, (M,M')3(PO4)2 (M,M' = Co, Mg or Zn), have been prepared by precipitation from the metal ion solution with (NH4)2HPO4 followed by calcination. The cation distribution of the five and six coordinate sites was determined and Co was shown to prefer the five coordinate site in the (Co,Mg)3(PO4)2 system, and an almost random distribution in the (Co,Zn)3(PO4)2 system.CsCoPO4 was synthesised via conventional solid state synthesis for the first time and was found to adopt the zeolite ABW structure with tetrahedral CoO4 units giving an intense dark blue colouration. The material was found to undergo a phase transition to higher symmetry at ca. 171°C.The commercial pigment Manganese Violet has been synthesised and EXAFS studies of the local manganese environment has shown it to be a distorted 4+2 octahedral Mn (III) centre coordinated to phosphate oxygen atoms. Variable temperature PXD has shown that the weight loss on heating at 100-250°C is likely to be loss of surface water as the diffraction pattern remains unchanged.The blue transition metal silicates Sr2CoSi2O7 and MCuSi4O10 (M = Ca, Sr, Ba) have been synthesised. Structural characterisation shows that substitution of larger alkaline earth metals increases the lattice parameters and effects the tetrahedral geometry in the cobalt system thus influencing the colour. The colour in the copper system changes as a result of the smaller dipole between the larger metal ions and the copper centre with the copper square planar geometry being relatively unperturbed.Commercial transition metal substituted rutile materials (Ni,Sb,Ti)O2 have been studied and the colour was shown to arise from Ni(II) d-d and Sb(V) charge transfer transitions. The colour was shown to be dependent on the relative atomic ratios of Ni and Sb. The novel (Ni0.25Ti0.25Nb0.5)O2 has been synthesised and the green/yellow material was found to adopt the rutile structure with a = 4.69702(2) Å and c = 3.02411(2) Å.</p
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
The long-lived nuclear singlet state of 15N-nitrous oxide in solution
No full textA 15N nuclear singlet lifetime of over 26 min has been observed in a solution of 15N2O, by using a field-cycling NMR pulse sequence. This observation suggests applications of hyperpolarized 15N2O in medical imaging and for flow and diffusion studies
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
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