1,720,986 research outputs found
Preparation and Application of Polymer Fibers Immobilized Catalysts
No full textThe development of highly active and recoverable catalysts has been the subject of research in recent decades. A systematic introduction of techniques for preparing polymer fibers immobilized catalysts, and a brief description of the it' s application are discussed. Compared with conventional non-polymer fibers immobilized catalysts, polymer fibers immobilized catalysts can meet high specific surface area,easy processing, easy separation and so on, and therefore possess a high catalytic activity and excellent cycle performance. Advances in techniques for preparing polymer fibers and methods for immobilizing catalysts significantly promote the progress of high-performance immobilized catalysts with polymer fibers for the carriers, so that the catalysts will exhibit important significance in air purification, sewage treatment, large-scale chemical production and other fields
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
Incorporation of 1,4-cyclohexanedicarboxylic acid into poly(butylene terephthalate)-b-poly (tetramethylene glycol) to alter thermal properties without compromising tensile and elastic properties
No full textThermal and tensile properties of thermoplastic elastomers (e.g. poly(butylene terephthalate)-b-poly(tetramethylene glycol) (PBT-PTMG)) are usually tuned by changing the composition of hard and soft segment parts. Simply increasing the amount of soft segment results in a lower melting temperature and better elastic properties, but the thermal stability and tensile properties are inevitably sacrificed. In this work, by incorporation of an aliphatic ring structure (i.e. 1,4-cyclohexanedicarboxylic acid) (CHDA) to partially replace the aromatic ring (i.e. terephthalic acid) in PBT-PTMG, the properties of the material can be tuned in such a way that the melting temperature decreases, while the thermal stability, tensile and elastic properties are not compromised. Moreover, manipulation of the stereo-chemistry of the CHDA unit discloses the "elastic" nature of the non-planar ring structure. Samples with a greater amount of cis-CHDA tend to have better tensile and elastic properties compared with their trans-CHDA counterparts
Controlling the status of corn cellulose solutions by ethanol to define fiber morphology during electrospinning
No full textResidual ethanol was used as an activation agent to control the status of corn cellulose (CN cellulose) solution and thereby the morphology of CN cellulose fibers after electrospinning. A suitable amount of ethanol could combine with the CN cellulose chains to reduce their ionic absorbance, improving the migration ability of ions in the cellulose-N,N-dimethylacetamide (DMAc)/LiCl-ethanol system. As a result, the entanglement of the molecular chains of CN cellulose in solution was reduced. Excess ethanol reduced the migration ability of ions and enhanced the strong entanglement of CN cellulose in solution. By thus adjusting the status of the CN cellulose solution, the fiber morphology and diameter distribution after electrospinning could be controlled. Based on the experimental results, this approach represents an important and effective approach using ethanol as an activation and adjusting agent for CN cellulose to achieve formation of high-quality electrospun fibers
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
How does epoxidized soybean oil improve the toughness of microcrystalline cellulose filled polylactide acid composites?
No full textChemical effect is mainly utilized to induce the accumulation of epoxide soybean oil (ESO) on the surface of microcrystalline cellulose (MCC) particles as the formation of flexible layer to produce superior toughness of polylactide acid (PLA) composites. MCC is firstly maleated to produce appropriate chemical reactivity with ESO and thus ESO is induced to form a flexible layer around MCC particles by chemical reaction happened in melt-blending, which is proved by the results from XPS and contact angle measurements. This flexible layer increases the interfacial adhesion and provides an easy deformation region. As a result, high toughness is provided. The elongation and impact strength of PLA/ESO/MCC ternary composites can be respectively improved to 38.5% and 31.7 KJ/m(2). This particular structure also helps to increase plasticization effect leading to a slightly decrease in T-g. The whole process elaborates a simple but an effective methodology to improve the toughness of PLA/cellulose composite in virtue of chemical effect. Toughness of PLA/ESO/MCC composites can be also controlled by the degree of chemical reaction (adjusted by the substitution degree of MA on MCC). Fully biodegradable PLA/ESO/MCC composite with high toughness is finally fabricated. (C) 2013 Elsevier Ltd. All rights reserved
- …
