1,721,055 research outputs found
‐tolerant oxide
No full textAbstract not availableYanying Wei, Qing Liao, Zhong Li, Haihui Wang, Armin Feldhoff and Juergen Car
A CO(2)-stable hollow-fiber membrane with high hydrogen permeation flux
No full textAbstract not availableYan Chen, Qing Liao, Zhong Li, Haihui Wang, Yanying Wei, Armin Feldhoff and Jurgen Car
A dual-phase ceramic membrane with extremely high H(2) permeation flux prepared by autoseparation of a ceramic precursor
No full textA novel concept for the preparation of multiphase composite ceramics based on demixing of a single ceramic precursor has been developed and used for the synthesis of a dual-phase H2 -permeable ceramic membrane. The precursor BaCe0.5 Fe0.5 O3-δ decomposes on calcination at 1370 °C for 10 h into two thermodynamically stable oxides with perovskite structures: the cerium-rich oxide BaCe0.85 Fe0.15 O3-δ (BCF8515) and the iron-rich oxide BaCe0.15 Fe0.85 O3-δ (BCF1585), 50 mol % each. In the resulting dual-phase material, the orthorhombic perovskite BCF8515 acts as the main proton conductor and the cubic perovskite BCF1585 as the main electron conductor. The dual-phase membrane shows an extremely high H2 permeation flux of 0.76 mL min(-1) cm(-2) at 950 °C with 1.0 mm thickness. This auto-demixing concept should be applicable to the synthesis of other ionic-electronic conducting ceramics.Shunfan Cheng, Yanjie Wang, Libin Zhuang, Jian Xue, Yanying Wei, Armin Feldhoff, Jîrgen Caro and Haihui Wan
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
Gas to liquids: natural gas conversion to aromatic fuels and chemicals in a hydrogen-permeable ceramic hollow fiber membrane reactor
No full textThe performance of a dense ceramic hydrogen-permeable membrane reactor for the nonoxidative methane dehydroaromatization (MDA), according to the equilibrium reaction 6CH₄ ⇆ C₆H₆+ 9H₂ with a 6 wt % Mo/HZSM-5 bifunctional catalyst was investigated. A U-shaped ceramic hollow fiber membrane of the composition La₅.₅Wₒ.₆Mo₀.₄O₁₁.₂₅−δ (LWM₀.₄) has been used for the in situ removal of H₂ to overcome thermodynamic constraints. The yield of aromatics (benzene, toluene, naphthalene) in the MDA could be increased in the beginning of the aromatization reaction by ∼50%–70%, in comparison with the fixed-bed reactor, because 40%–60% of the H₂ abstracted have been extracted at 700 °C with a weight hourly space velocity (WHSV) of 840 cm³ gcat¯¹ h¯¹. These advantages of the membrane reactor operation decrease with time on stream, since the removal of H₂ boosts not only CH₄ conversion and yield of aromatics, but also catalyst deactivation by deposition of carbonaceous deposits. However, the catalyst system could be regenerated by burning the coke away with air.Jian Xue, Yan Chen, Yanying Wei, Armin Feldhoff, Haihui Wang, and Juergen Car
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
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