1,720,954 research outputs found
Near to eye projection systems
No full textAR displays experience limited FOV, low efficiency and high weight partly due to the use of SRGs. Investigated here are improvements to HUDs, replacing gratings with novel structures and high throughput fabrication. Design and fabrication improved upon current systems for diffractive elements and materials. Fabrication produced these in a high transparency, high refractive index glass. Structures were evaluated and improvements over conventional gratings found, enabling improved optics for novel augmented reality devices.A new type of diffractive structure was produced, demonstrating to our knowledge the structure of this kind in transparent materials. Silicon oxynitride deposition for low-absorption hydrogen-free layers with a tuneable refractive index range greater than other methods, was demonstrated at ambient temperatures.<br/
Anisotropic Ta2O5 photonic crystal waveguide etching using inductively coupled plasma etching
No full textAchieving smooth and vertical sidewall profile in the 2D photonic crystals (PhCs) is crucial for the photonic crystal waveguides (PCWs) in integrated optical devices, since “volcano” shaped PhCs lead to light leakage and the drift of photonic bandgap. This paper optimizes the inductively coupled plasma reactive ion etching (ICP-RIE) process for improving the sidewall profile of Ta 2 O 5 PCW with minimum PhC dimension of 300 nm pitch and 185 nm diameter. A set of experiments was generated by statistical software (minitab) to efficiently investigate the region of interest in the process space by varying RF platen power, ICP power, % C 4 F 8 in gas mixture ( C 4 F 8 and O 2 ), and chamber pressure. Subsequently, the most suitable experimental conditions were identified and used as the central run for analyzing the influence of individual parameters on ICP etching of Ta 2 O 5 . Key findings include the importance of maintaining a 50% C 4 F 8 in total gas flow and trade-offs related to ICP and RF power adjustments. Pressure has a negligible impact on sidewall angle but exerts a more pronounced influence on etch rate and micromasking. A delicate balance among these parameters is crucial for optimal etching results. The recommended recipe (50 W RF platen power, 2000 W ICP power, 10 mTorr pressure, 50% C 4 F 8 in total gas flow) achieves an etch rate of 113.325 nm/min with a smooth and vertical sidewall in PhCs. The entire etching exploration process was conducted on a Ta 2 O 5 layer deposited on a Si substrate. Additionally, this recipe was applied to etch Ta 2 O 5 with a 2 μ m SiO 2 layer interposed between the Ta 2 O 5 layer and the Si substrate, yielding favorable results and preserving the integrity of the PhC sidewall.</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
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
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
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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