1,720,954 research outputs found
LARGE AREA LIGHT SOURCE AND LARGE AREA LUMINAIRE
No full textA light source (25) for emitting collimated light (29) in particular for a large area luminaire (21) comprises a light guide unit (43) optionally comprising a plurality of light guide strips (91) configured for guiding light received at the at least one lateral coupling face (47), for example, by total internal reflection. The light guide strips comprise a plurality of localized light source regions (57) at a main front face (55A) for having light pass there through, wherein the light source regions (57) are provided along the light guide strip (91) within a non-source region (59). The light source (25) further comprising a plurality of light emitting units (41) for emitting light into the light guide strips (91) through respective portions of the at least one coupling face (47), and a collimation unit (45) extending along the main front face (55A) and comprising a plurality of collimating elements. Each collimating element, which may be a compound parabolic concentrator or TIR lens, comprises an input side and an output side, is optically associated to one of the plurality of light source regions (57), and is configured to receive light emerging from the associated light source region (57) at its input side and to emit collimated light (29) from a respective collimated light emitting region (61) formed at its output side. In another embodiment the light emitting units are configured to emit primary light having a spectral distribution that compensates for spectral losses accumulated by the primary light while propagating within the light guide unit. In a further embodiment the collimated light has a direction that is tilted with respect to the normal to a light emitting face of the light source. In an additional embodiment the ration of the area of the plurality of light source regions with respect to the area of the main front face and/or the area of the non-source region is less than or equal to 20%. In a further embodiment a plurality of reflective structures is associated with the light source regions
SUNLIGHT-BASED LARGE AREA LIGHT SOURCE AND LARGE AREA LUMINAIRE
No full textA light source (25) for emitting collimated light (29) in particular for a large area luminaire (21) comprises a light guide unit (43) for guiding light by total internal reflection. The light guide unit comprises a plurality of localized light source regions (57) at a main front face (55A) for having light pass there through. The light source (25) further comprises a plurality of light emitting units (41) for emitting light into the light guide strips (91) through respective portions of the at least one coupling face (47) of the light guide unit (43), and a collimation unit (45) extending along the main front face (55A) and comprising a plurality of collimating elements. At least one light emitting unit (41) is configured as a light input coupling assembly (250) to receive collected natural light from a fiber (249) and to provide the received natural light to the light guide unit (43). The light source (25) can be implemented in a sunlight-based illumination system (241) collecting and providing natural light to the light source (25)
Native oxidation of selectively disordered aluminum gallium arsenide quantum well heterostructures: Deep oxide structures for high performance lasers and waveguides
No full text"Data are presented showing that ""deep,"" device-quality native oxide structures can be formed in selected areas in \rm Al\sb{x}Ga\sb{1-x}As-GaAs quantum well heterostructure (QWH) crystals. The deep oxides are formed using a combination of improved area-selective impurity-induced layer disordering (IILD) and water vapor oxidation at an elevated temperature (525\sp\circC). The resulting oxide extends from the QWH crystal surface into the lower confining layers, penetrating the active region and forming a deep, insulating, low-refractive-index structure with a smooth interface that is free of defects and dislocations."Data are presented on devices utilizing the large lateral index step provided by the deep oxide, including high performance AlGaAs-GaAs QWH stripe-geometry laser diodes, waveguides with low bend loss, and low-threshold curved-geometry lasers. These devices display tight routing capability and suggest compact, integrable geometries for reducing the real-estate requirements (and the cost) of the optoelectronic integrated circuits and for offering less constraint in circuit design.Made available in DSpace on 2011-05-07T13:37:24Z (GMT). No. of bitstreams: 2
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Previous issue date: 1995Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:57:06Z
Item is restricted indefinitely.Restriction data tranferred 2014-07-01T11:26:45-05:00
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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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