1,721,075 research outputs found
A STUDY OF LATTICE DAMAGE IN SILICON INDUCED BY BF2+ ION-IMPLANTATION
No full textLattice damages induced by BF2+ ion implantation in single-crystalline silicon have been analyzed using secondary-ion mass spectrometry, ion channeling technique in Rutherford backscattering spectroscopy, and transmission electron microscopy. Concentration depth profiles of boron and fluorine showed the same values of projection range 400 angstrom at all doses for 50-keV energy. A considerable amount of damage was formed in the silicon lattice and the surface region of the substrate was amorphized when the dosage exceeded a critical value, which was determined to be 8.0 x 10(14)/cm2 experimental dose. The amorphized layer showed a clear boundary to the crystalline silicon, which contains severly damaged regions identified to be microamorphous clusters. He2+ ion channeling data revealed that the integrated damage in implanted layers increases linearly with dosage up to the critical dose and increases with a much smaller rate with further increase in the dosage. It is suggested that the integrated damage shows a smaller damage rate once the surface was amorphized because there can be no further increase of lattice damage in the amorphous layer. The calculated values of the integrated damage based on a model for damage formation agree well with the measured ones
Effects of reinjection on the scaling property of intermittency
No full textWe study the effect of the reinjection probability distribution (RPD) on the scaling property of intermittency via the renormalization group approach. When the lower bound of reinjection is below the tangent point, the critical exponent has the well known form of (z - 1)/z independent of the RPD. On the other hand, when the lower bound of reinjection is at the tangent point, the critical exponent is (z + gamma - 2)/z if the RPD is of an algebraic form with exponent gamma and is (z - 1)/z if the RPD is fixed at the tangent point. The results are confirmed by numerical simulations
GEOMETRIC PHASE IN A SYSTEM OF 2 QUARTER-TURN OPTICAL FIBERS
No full textThe value of the geometric phase observed with two disconnected uniformly wound quarter-turn optical fibers and a linear polarizer between them is quite different from that measured with a uniformly wound half-turn optical fiber, although evolution curves in the propagation vector sphere for the above-mentioned cases are the same. We try to analyze the experimental data by applying the geodesic rule separately to each evolution curve for the two quarter-turn fibers, and the theoretically obtained values are in good agreement with the experimental data
INFLUENCE OF TIAS PRECIPITATE FORMATION ON MORPHOLOGY DEGRADATION OF THE TISI2/AS-DOPED POLYSILICON SYSTEM
No full textThe formation of TiAs precipitates between TiSi2 with C54 structure and arsenic-doped polysilicon and the influence of TiAs and silicon resulting from the reaction TiSi2 + As --> TiAs + 2Si on layer morphology degradation have been studied. The formation of TiAs precipitates has been revealed by X-ray diffraction in a sample annealed at 900-degrees-C for 60 min and a sequential increase in sheet resistance with increasing annealing time has been observed. Cross-sectional scanning electron microscopy of the sample annealed for 60 min has shown irregular-shaped protrusions. Point analyses by Auger electron spectroscopy and cross-sectional transmission electron microscopy of the same sample have shown the presence of TiAs precipitates and extra silicon near the TiSi2 - polysilicon interface under the protrusion area. From the results it has been found that TiAs precipitates and extra silicon resulting from the reaction TiSi2 + As --> TiAs + 2Si lead to morphology degradation of this system
Rapid Thermal Annealing of GaAs Films on (001) Si Substrate Grown by Solid Phase Epitaxy Technique
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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
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