1,721,009 research outputs found
Aluminum textile-based binder-free nanostructured battery cathodes using a layer-by-layer assembly of metal/metal oxide nanoparticles
No full textDespite considerable interest in textile-based battery electrodes with large surface areas and mechanical flexibility, issues have restricted further advances in the energy performance of textile electrodes. These issues include the ineffective incorporation of conductive and/or active components into textile frameworks, the poor charge transfer between energy materials, and the formation of numerous unstable interfaces within textile electrodes. Herein, we introduce an aluminum textile-based lithium-ion battery cathode with remarkable areal capacity, high rate performance, and good cycling stability. Ligand exchange reaction-induced layer-by-layer (LbL) assembly of metal nanoparticles and small molecule linkers, with subsequent metal electroplating, perfectly converted polyester textiles to 3D-porous aluminum textiles that can be used as current collectors and high-energy reservoirs. The consecutive LbL assembly of high-energy LiFePO4 and conductive indium tin oxide nanoparticles onto the aluminum textiles using small organic linkers significantly increased the areal capacity and cycling stability (at least 580 cycles) of the resultant cathode, allowing facile charge transfer within the textile electrodes. Furthermore, the areal capacity of these textile electrodes increased from 1.07 to 3.28 mA h cm-2, with an increase in the folding number from 0 to 2. © 2021 Author(s).1
Development of a novel synthetic method for aliphatic ester dendrimers
No full textAliphatic ester dendrimers based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) growth units were successfully synthesized as a form of dendritic hybrids up to G4. Linear polystyrene supports in the dendritic hybrids were obtained through atom transfer radical polymerization at 130 degrees C for 12 h using the CuCl/PMDETA catalyst/ligand system with 4-(chloromethyl)benzyl alcohol as the initiator. An optimized molecular weight of 8700 was chosen as the support, considering the difference in solubility between the dendritic hybrids and the growth units as well as the effective characterization of the end functional groups in the H-1 NMR analysis. The dendritic repeating units were grown from the benzyl alcohol end functional group of the support via a typical esterification process in methylene chloride for 12-24 h at 25 degrees C. The resulting hybrids were purified by a simple precipitation into methanol without any chromatographic separation, utilizing the difference in solubility between the poorly soluble dendritic hybrids and highly soluble growth units. At the final step, the dendrimers were obtained via the selective cleavage of the benzyl ester group connecting the polymeric supports and the dendrimers using a paladium(II) acetate catalyst in DMF (10 equiv volume of dendritic hybrid) for 24 h under the hydrogen pressure of 6 atm. The dendritic hybrids and dendrimers obtained with 100% conversion yield were characterized by H-1 NMR, C-13 NMR, and gel permeation chromatography. It is believed that this simplified purification procedure in the proposed synthesis will be suitable for the production of high-generation dendrimers on a large scale.Korea Research
Foundation for financial support through Grant No. R08-2003-
000-10176-0 and the Ministry of Science and Technology (No.
M10414030002-05N1403-00200) in Kore
Synthesis of novel biodegradable cationic dendrimers
No full textDendrons and dendrimers with cationic amino groups at their periphery were successfully synthesized up to the third and second generation, respectively. The results obtained by (1)H NMR spectroscopy and gel permeation chromatography analysis supported the formation of the targeted dendrons and dendrimers. The dendrons were grown via ester linkages, which endowed them with biodegradability in D(2)O at 37 degrees C. The degradation rate depends upon the steric hindrance and reactivity caused by the bulkiness and compact structure of the dendrons. All of the synthesized dendrons were degraded within a month, while 60% of the ester groups in the sterically crowded dendrimers were degraded over the same time period. The cytotoxicity of the dendrons was evaluated by the MTT assay on a 293T cell line which indicated that the obtained dendrons were completely non-toxic. These non-toxic, biodegradable cationic dendrons and dendrimers are believed to have potential applications in the biomedical field.the Ministry of Science and Technology (No. M10414030002-
05N1403-00200), Korea
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
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
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