1,721,047 research outputs found
Optical and electrical properties characterisation of photovoltaic spatial-light modulators
No full textLiquid crystal photovoltaic spatial-light modulators use photovoltaic layers as an integrated power source to switch from a transparent to an opaque state depending on the ambient illumination. We use non-invasive cross-polarised intensity measurements, to fit photovoltaic parameters, namely photo-generated voltage and photoconductivity, in a sealed device and map their variation across its surface. This methodology was used to estimate the effect of light intensity on these devices and to monitor changes of the photovoltaic parameters over a nine-month period.</span
Integrated organic donor-acceptor bulk heterojunctions for self-activated liquid crystal light modulators
No full textOptically addressed spatial light modulators (OASLM) are promising for holographic applications and optical limiters. Self-activated OASLMs can operate as autonomous energy devices, opening the route to stand-alone laser protection devices and smart windows. They are mainly based on liquid crystal (LC) devices, integrated with inorganic photovoltaic substrates such as LiNbO3:Fe or dye-sensitized TiO2. While robust, they also suffer from several restrictions such as high costs, low performances and/or small device area. In this work, we propose a new type of an autonomous modulator. Blends of electron-donating (D) conjugated polymers and electron-accepting (A) fullerene molecules were used as a photovoltaic thin films and integrated into liquid crystal device. Such D/A bulk heterojunctions are the major building block of solution-processed organic solar cells and are known to convert incident light into electrical energy. In our case, the organic layer generates a photovoltaic field that is used to control the LC alignment under illumination. We carried out cross-polarized intensity measurements on this photovoltaic-LC device to demonstrate the expected occurrence of a light-dependent birefringence change, without an applied voltage. In this way, by combining solution-processed organic photovoltaic thin films with optical responsive liquid crystals, our work paves the way to low cost and large area self-sustained optical devices.</p
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
Dataset in support of the article 'Optical and electrical properties characterisation of photovoltaic spatial-light modulators'
No full textSupporting information and data related to the paper "Optical and electrical properties characterisation of photovoltaic spatial-light modulators",
The dataset contain a .pdf named "Optical and electrical properties characterisation of photovoltaic spatial-light modulators - Supporting information" that displays the methods to assemble photovoltaic units and PSLMs, along with Figure S.1, Figure S.2, Figure S.3. A .txt named "readme_SI" explains how the dataset is organised and provide information related to the publication.
The dataset also contain a .zip folder named "Optical and electrical properties characterisation of photovoltaic spatial-light modulators - Data" that contain all the data measured that has been fitted and presented in the article. A .txt named "readme" explains how the folder is organised and provide information related to the publication.
For any futher information, please contact me at [email protected].</span
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
Mapping quality and parameters of photovoltaic liquid crystal modulators
No full textPhotovoltaic light modulators integrate liquid crystals and solar cells and offer an exciting prospect for autonomous, smart displays and visors. Illumination produces a photovoltage that modifies the liquid crystal alignment and light transmission. However, determining their properties, for example, the voltage dropped across the liquid crystal, different pretilts or anchoring energies, inherent to asymmetric cell designs, poses significant challenges. We have successfully applied to such photovoltaic modulators a new measurement methodology based on wide-area cross-polarized intensity measurements, coupled to an Ericksen-Leslie model. We have implemented it in a versatile optical analyzer, driven by a Matlab graphical user interface
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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