1,720,971 research outputs found
Investigation of the relation between growth mechanism and material properties of amorphous silicon solar cells
No full textThin film silicon solar cells are produced by using plasma deposition techniques. With this technique a thin film layer of silicon, most commonly amorphous silicon (a-Si: H), can be deposited on a substrate. The material properties depend largely on the plasma properties and the growth mechanism. The investigation of the correlation between material properties and the ion bombardment, which are important for electronic device operation, is the sole aim of this thesis. Expanding Thermal Plasma Chemical Vapour Deposition (ETP-CVD) is used for the deposition of a-Si: H layers. With this deposition technique, growth rates in excess of 1nm/s can be achieved. Through this, the production cost of solar cells can be reduced because of the increase in the production output. The growth mechanism of a-Si:H layers deposited with this technique has been extensively investigated and it has been shown that SiH3 radicals contribute to about 90% of the growth. The growth mechanism of a-Si: H layers can be manipulated by applying a bias to the substrate. In this way, the contribution of ions to the growth and the ion energy can be varied. To induce ion bombardment during film growth, a non-sinusoidal pulse-shaped signal is applied to the substrate and the material properties, which include optical properties, structural properties, and electrical properties, are measured. Denser a-Si:H films are obtained with increasing ion energy, indicating material densification. Higher growth rate is observed because of the production of more radicals around the substrate. An increase in photoconductivity is obtained up to 100V, which correlates with the decrease in the Tauc band gap and the densification of the material. Increase in the ion bombardment leads to decrease in the microstructure, which indicates reduction of voids in the material. However, defect density and Urbach energy increases with the ion bombardment due to the creation of weak bonds which end up as defects in the a-Si:H films. The optimized layers of the measured samples are incorporated into solar cells. Solar cells that are produced with pulse-shaped bias voltage up to 50V yielded a conversion efficiency of 6.2%. The efficiency is lower at higher voltages, which is mainly caused by smaller Voc and FF because of high defect densities present in the intrinsic layers at higher voltages.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc
A Relaxed Kaanov iteration for the p-poisson problem
No full textDiening L, Fornasier M, Tomasi R, Wank M. A Relaxed Kaanov iteration for the p-poisson problem. Numerische Mathematik. 2020;145:1-34.In this paper we introduce and analyze an iteratively re-weighted algorithm, that allows to approximate the weak solution of the p-Poisson problem for 1<p2 by iteratively solving a sequence of linear elliptic problems. The algorithm can be interpreted as a relaxed Kaanov iteration, as so-called in the specific literature of the numerical solution of quasi-linear equations. The main contribution of the paper is proving that the algorithm converges at least with an algebraic rate
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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