1,720,985 research outputs found
Polarization-controlled, single-transverse-mode, photonic-crystal, vertical-cavity, surface-emitting lasers
No full textWe developed a polarization-controlled, single-transverse-mode, photonic-crystal, vertical-cavity, surface-emitting laser (PC-VCSEL) by introducing elliptical air holes in the top mirror. The polarization-controlled PC-VCSELs show polarization extinction ratios of over 29 dB. The origin of the polarization stability is explained by the asymmetric polarization mode profile and the asymmetric current injection profile. (C) 2003 American Institute of Physics.This work was supported by the National Research
Laboratory Project of KISTEP, Korea. We appreciate the
technical support of the OPTICIS
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
1.5 mu m vertical-cavity surface-emitting lasers utilising low loss AlxOy/GaAs mirrors
No full textLow threshold power vertical-cavity surface-emitting lasers are fabricated by using low loss AlxOy/GaAs mirrors as output couplers. A 5 mu m-aperture laser with a low threshold CW pump power of 1.4 mW at room temperature and a 16 mu m-aperture laser operating in CW mode up to 64 degrees C are produced
Continuous room-temperature operation of optically-pumped two dimensional photonic crystal lasers at 1.6 ㎛
No full textInGaAsP microdisk lasers on AlxOy
No full textInGaAsP microdisk lasers are fabricated on AlxOy by wafer fusion, Room-temperature continuous-wave operation with threshold pump power of 1.13 mW has been achieved from a 2.2-mu m diameter microdisk laser. The lasing wavelength with incident pump power redshifts at a rate of 0.28 mm/mW which shows the improved thermal characteristics due to the high thermal conductivity of AlxOy bottom layer
Continuous room-temperature operation of optically pumped two-dimensional photonic crystal lasers at 1.6 mu m
No full textIn this letter, continuous operation is realized from two-dimensional slab photonic crystal lasers at room temperature, The laser structure is prepared by wafer fusion of an InGaAsP active layer with an AlAs layer that is wet oxidized into an Al2O3 layer subsequently. The incident threshold pump power at 0.98 mum is 9.2 mW for a similar to 10-mum-diameter hexagonal cavity lasing at 1.6 mum.The authors thank Samsung Electronics, Suwon, Kyonggi,
Korea, for the AlGaAs wafer used in the experiment
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
- …
