1,720,970 research outputs found
Magnetotransport properties of (Ge,Mn) ferromagnetic semiconductor grown on GaAs(001)
No full text利用低溫分子束磊晶的方法，在兩種砷化鎵基板上成長具奈米微結構之鍺錳鐵磁性半導體：磊晶型砷化鎵基板(Ga-GeMn)及非晶質砷覆蓋之砷化鎵基板(As-GeMn)。
在Ga-GeMn試片，鍺錳薄膜中含有自組性高錳奈米圓柱微結構，其成長會垂直表面，故平整面度不同會使奈米圓柱成長呈現平行或交錯狀。磁性量測含兩個相：居里溫度150K之鐵磁高錳奈米圓柱及低濃度錳原子在鍺母體之順磁相。由磁性傳輸特性量測，此P型薄膜具有異常性霍爾效應，並存在不同的磁阻特性：低溫的巨磁阻特性，高溫的磁場二次方之常態磁阻及低磁場具有額外正磁阻。藉由此P型半導體與高錳奈米圓柱之能帶結構，我們也提出一磁性傳輸特性模擬計算之方法，定性地解釋實驗上薄膜之異常性霍爾效應來自高錳奈米圓柱及低磁場具有額外正磁阻(稱為霍爾磁阻)。
在As-GeMn試片，砷原子擴散改變薄膜之成長機制，由二維變成三維成長：居里溫度50K之奈米析出相與鐵磁性之Ge3Mn5聚集相。施體錳與受體砷主導薄膜之電子傳輸特性並發現其補償效應，磁性傳輸量測發現其高非等向性磁阻特性來自於弱局部化現像。此N型鐵磁半導體與金屬性奈米析出物形成蕭基位能障，此位能障始電子傳輸在等向性量測時具穿隧磁阻效應。By low temperature Molecular Beam Epitaxy (MBE), (Ge,Mn) thin films with ferromagnetic nanostructures are grown on two kind of GaAs substrates: epiready GaAs(001) (Ga-GeMn) and GaAs(001) with amorphous As capping layer (As-GeMn).
In the Ga-GeMn samples, we observe self-organized Mn-rich nanocolumns which, depending on the initial surface morphology, are either parallel or entangled. Magnetic measurements evidence two magnetic phases: ferromagnetic nanocolumns with Curie temperature around 150K, and the Ge matrix made paramagnetic by diluted Mn. From measurements of magnetotransport, this p-type layer exhibits anomalous Hall effect (AHE) and various magnetoresistivity (MR): negative Giant MR at low temperature, parabolic ordinary MR, and an additional positive MR at low field. The simulation of magnetotransport properties has been initiated, with some assumptions on the energy-band diagram of p-type Ge semiconductor and Mn-rich nanocolumns, and shows the way that AHE in the inclusions induces AHE in the whole layer, and a mechanism of MR which accounts for this contribution (which we call Hall MR).
In the As-GeMn samples, the outdiffusion of As atoms changes the growth mechanism, from a 2D spinodal decomposition to a 3D one with the formation of nanoprecipitates with Tc=50K and of ferromagnetic Ge3Mn5 clusters. Compensation effect between Mn (donor) and As (acceptor) dominates the transport behaviors. A highly anisotropic MR is observed in n-type (Ge,Mn) films and shown to be due to weak localization effects. Another contribution is tentatively attributed to tunneling MR due to the Schottky barrier, which forms at the interface between the metallic Mn-rich inclusions and the n-type Ge semiconductor
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
- …
