1,721,236 research outputs found
Preparation and characterization of a nano-sized Mo/Ti mixed photocatalyst
No full textNano-sized molybdenum-doped TiO(2) (Mo/Ti) mixed oxide photocatalysts were prepared with the Mo(5+) content varying from 0 up to 2.5 mol%, to shift the absorption onset into the visible region and to enhance the efficiency of photocatalytic activity by retarding the (e(-)-h(+)) recombination. Prepared Mo/Ti mixed oxides were characterized by ultraviolet and visible spectroscopy (UV/VIS), transmission electron microscopy-electron diffraction pattern (TEM-EDP), X-ray diffraction(XRD), energy dispersive X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS). Photonic efficiency was also investigated with the degradation rate of dichloroacetate (DCA) and light intensity measured by actinometry. TEM-EDP and XRD patterns showed that particles were in the form of anatase with the diameter of ca. 4 nm. The appreciable red-shift in the UV/VIS absorption spectra was monitored at each preparation stage - aging and dialyzing. The red-shift varied with addition of Mo, in the case of 2.5% Mo/Ti the UV/VIS absorption started at around 0.22 eV less than in nano-sized pure TiO(2) (about 3.42 eV). EDAX verified that the amount of Mo in the prepared mixed oxides was as required, and XPS analysis revealed that Mo(V) existed in the TiO(2) lattice. The measured photonic efficiency increased to 0.28 with DCA at 0.5 mol% Mo, and then decreased as the Mo content increased above 0.5 mol% Mo. This could be explained in terms of the changing prevailing phenomena - electron trapping and recombination - as the amount of dopant increased in terms of the distance between the trapped sites of the charge carriers. (C) 2000 Elsevier Science B.V. All rights reserved.The authors wish to thank the Ministry of Science and Technology of Korea for financial support as a project for National Research Laboratory and Prof. J.Y. Lee at Material Engineering in Korea Advanced Institute of Science and Technology (KAIST) for the analysis by TEM–ED
Reduction of disability after stroke is a more informative predictor of long-time survival than initial disability status
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A study on the relationship of sexual activity to physical diseases among the elderly aged 65 and over in Taiwan
No full textLong-term mortality assessment using biological measures among elderly people: ten-year follow-up of 597 healthy elderly cohort in Taiwan
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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
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