1,721,014 research outputs found

    Sustainable synthesis of gold nanorods assisted by cubic-shaped seeds as intermediate particles

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    We demonstrate a simple and novel approach for continuously production of gold nanorods via seed-mediated technique. By utilizing a critical shape of seeds (e.g. cubic-shaped particle) which is prepared by incubation at 35 °C, we found that this specific seed can effectively transform into nanorods. The advantage of this synthesis route can offers stable seeds to generate nanorods, even undergo long-term aging process, and would significantly reduce the amount and frequency use of hazardous material (e.g. NaBH4) for preparing the fresh seed solution. Reliability for scalable and repeatable production of this method are discussed

    Ionic-to-electronic coupling efficiency in PEDOT:PSS films operated in aqueous electrolytes

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    Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS, is a polymeric mixed conductor used in the vast majority of devices in bioelectronics, electrochromics, energy storage/generation, neuromorphic computing, and thermoelectrics. These devices operate at the interface with electrolytes and rely on the uptake of mobile ions by the film, making the coupling between electronic and ionic charges crucial. For efficient transduction of ionic charges into electronic ones, all the ions injected into the film should lead to a change in conductivity. Although extensively studied, fundamental knowledge regarding the losses during this process is lacking. In this study, we quantify the efficiency of ion-to-electron coupling in PEDOT:PSS films by measuring the number of cations taken up by the film as well as the in situ current generated as a result of their interactions with the electrically active sites. We find that not all the injected cations are used for reducing PEDOT oligomers in thick films and some of these ions remain in the film upon de-doping. The efficiency of ion-to-electron transduction thus varies with thickness, a parameter which critically affects the distribution of PEDOT and PSS in the bulk as revealed by Raman spectroscopy, X-ray photoelectron spectroscopy and scanning transmission electron microscopy studies. Tracking the traces of ions, we provide guidelines on how to maximize the coupling between ionic and electronic charges for high performance transducers. Our approach is thus fundamental to future development and optimization of mixed conductors applied at the interface with electrolytes.The authors would like to thank Jokubas Surgailis for his assistance in EQCM-D analysis and Jonathan Rivnay for fruitful discussions

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Ionic-to-electronic coupling efficiency in PEDOT:PSS films operated in aqueous electrolytes

    No full text
    Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS, is a polymeric mixed conductor used in the vast majority of devices in bioelectronics, electrochromics, energy storage/generation, neuromorphic computing, and thermoelectrics. These devices operate at the interface with electrolytes and rely on the uptake of mobile ions by the film, making the coupling between electronic and ionic charges crucial. For efficient transduction of ionic charges into electronic ones, all the ions injected into the film should lead to a change in conductivity. Although extensively studied, fundamental knowledge regarding the losses during this process is lacking. In this study, we quantify the efficiency of ion-to-electron coupling in PEDOT:PSS films by measuring the number of cations taken up by the film as well as the in situ current generated as a result of their interactions with the electrically active sites. We find that not all the injected cations are used for reducing PEDOT oligomers in thick films and some of these ions remain in the film upon de-doping. The efficiency of ion-to-electron transduction thus varies with thickness, a parameter which critically affects the distribution of PEDOT and PSS in the bulk as revealed by Raman spectroscopy, X-ray photoelectron spectroscopy and scanning transmission electron microscopy studies. Tracking the traces of ions, we provide guidelines on how to maximize the coupling between ionic and electronic charges for high performance transducers. Our approach is thus fundamental to future development and optimization of mixed conductors applied at the interface with electrolytes

    Variations on the Author

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    “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

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    We 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

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    We 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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