1,720,957 research outputs found
Efficient optical parametric chirped-pulse amplification using and crystals
No full text학위논문(박사) - 한국과학기술원 : 물리학과, 2011.2, [ vi, 60 p. ]다른 borate 비선형 결정에 비해 높은 비선형광학 계수를 가지고 있는 (BiBO) 결정은 단파장 영역의 파장에 대한 광유도 데미지에 의해 파장변환 응용에 많은 제약을 받아왔다. 본 논문에서는 BiBO 결정에 발생한 광유도 데미지를 극복하기 위한 방법들에 대한 연구와 함께 BiBO 결정을 이용한 펄스처핑 광매개증폭에 관한 연구를 수행하였다. 광유도 데미지에 대한 연구를 수행하기 위하여 BiBO 결정 성장을 통해 높은 결정질을 가지는 크기 에 무게 44g의 BiBO 결정을 얻었다. 이 BiBO 결정을 이용한 청색 파장용 DPSSL 레이저 실험 중 발생한 광유도 데미지에 대한 연구를 수행하였으며, 실험을 통해 BiBO 결정에 발생한 데미지가 광굴절 효과에 의한 것임을 증명하였다. 이러한 광굴절 효과를 극복하기 위한 방법으로 높은 온도에서의 광굴절 효과를 주는 레이저 빔에 대한 굴절률 변화를 측정하여 레이저의 세기에 무관하게 결정온도 120 C 이상에서는 광굴절 효과가 나타나지 않음을 증명하였다. 이러한 결과는 BiBO 결정의 청색 영역 및 그 이하의 단파장 영역에 대한 파장 변환 응용에 있어 많은 가능성을 제시해 주는 결과라고 할 수 있다.
펄스처핑 광매개증폭계에서 문제가 되는 펌프광에 의한 광학부품의 손상을 막기 위해, BiBO 결정의 높은 비선형광학 계수를 이용하여 낮은 펌프광의 세기에 응용가능성이 높은 펄스처핑 광매개증폭 실험을 진행하였다. 기존에 펄스처핑 광매개증폭계에서 가장 널리 사용되어온 BBO 결정과의 1단의 광매개증폭 특성 비교를 통해 BiBO 결정이 낮은 펌프광에서 매우 우세한 결정임을 증명하였다. BiBO 결정과 BBO 결정의 연속적 구조로 배열한 2단의 펄스처핑 광매개증폭을 통해 펌프 세기 260 MW/에서 의 증폭 이득을 얻었으며, 에너지로 보았을 때 0.17nJ의 신호광을 이용하여 2.1mJ의 증폭된 빔을 얻었다.
본 실험을 통해 고출력의 펄스처핑 광매개증폭계에서 광학부품의 광손상을 줄이면서 안정적으로 신호광의 증폭을 이룰 수 있는 계기를 마련하였다.한국과학기술원 : 물리학과
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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