1,721,044 research outputs found

    Envelope Solutions for Random Phase Plasmons(非線型非平衡統計力学研究会報告,基研研究会報告)

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    この論文は国立情報学研究所の電子図書館事業により電子化されました

    セツドウオウケタキドウノコウカニヨルヨワイランリュウノリロンノホセイ

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    京都大学0048新制・課程博士理学博士甲第1340号理博第285号新制||理||177(附属図書館)3891UT51-48-E557京都大学大学院理学研究科物理学第一専攻(主査)教授 田中 茂利, 教授 巽 友正, 教授 富田 和久, 教授 松原 武生学位規則第5条第1項該当Kyoto UniversityDA

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Pulse Expansion and Doppler Shift of Ultrahigh Intense Short Pulse Laser by Slightly Overdense Plasma

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    The interactions between ultrahigh intense laser and overdense plasmas were investigated by the use of a 1-1/2 dimensional electromagnetic relativistic particle-in-cell code, EMPAC. When the effective electron plasma frequency is reduced below the laser frequency by increasing the inertial electron mass due to the relativistic effect, the ultrahigh intense short pulse laser can penetrate the overdense plasma, but is completely reflected after propagating to a certain extent, except for a portion of the absorbed laser. The pulse length of the reflected laser is expanded more than that of the incident laser by a modulation due to the anomalous penetration, and the pulse expansion factor can be predicted by the schematic model. The frequency of the reflected laser can be calculated by the Doppler shift formula coupled with a relativistic dispersion relation, and is good agreement with the simulation result. The anomalously penetrating pulse shows soliton-like behaviors in the plasma after the incident laser has vanished

    Pulse Expansion and Doppler Shift of Ultrahigh Intense Short Pulse Laser by Slightly Overdense Plasma

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    The interactions between ultrahigh intense laser and overdense plasmas were investigated by the use of a 1-1/2 dimensional electromagnetic relativistic particle-in-cell code, EMPAC. When the effective electron plasma frequency is reduced below the laser frequency by increasing the inertial electron mass due to the relativistic effect, the ultrahigh intense short pulse laser can penetrate the overdense plasma, but is completely reflected after propagating to a certain extent, except for a portion of the absorbed laser. The pulse length of the reflected laser is expanded more than that of the incident laser by a modulation due to the anomalous penetration, and the pulse expansion factor can be predicted by the schematic model. The frequency of the reflected laser can be calculated by the Doppler shift formula coupled with a relativistic dispersion relation, and is good agreement with the simulation result. The anomalously penetrating pulse shows soliton-like behaviors in the plasma after the incident laser has vanished.journal articl

    Variations on the Author

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    “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

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    We 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
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