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Proximity Effect and Interfacial Resistance in Nb/Ni Multilayer.
No full text我們主要在研究超導與鐵磁物質的介面性質，我們選用的鐵磁材料是具有磁性的鎳金屬(Ni)，而超導材料是選用元素鈮(Nb)，鈮是元素超導中，超導轉變臨界溫度(TC)最高的，而且也是元素超導中少數為二類超導體的材料。這也給了我們許多空間去研究超導與鐵磁間的介面現象。流平行膜面(CIP)量測可以得到樣品的超導轉變臨界溫度與上臨界磁場(HC2)，在本文討論中是用Ni(50nm)/Nb(x)/Ni(50nm)三層膜的系統來看臨界溫度隨著鈮厚度的變化，數據中得到當鈮的厚度減少時，超導臨界溫度會降低的比純鈮系統快，我們可以根據介面效應的機制來擬合並得到一個超導臨界厚度(dSC~45nm)且分析其介面效應的強度，因為旁邊鐵磁層的磁交換場對庫柏電子對有拆散作用，所以當鈮的厚度在臨界厚度以下，即使溫度降至我們量測系統的最低溫度(1.7K)，超導特性也不會出現。C2的樣品是[Ni(50nm)/Nb(x)]6/Ni(50nm)多層膜的結構，在不同磁場下量測電阻與溫度的關係，定義出超導轉變臨界磁場，量測上分為磁場垂直膜面與平行膜面，但主要要看平行膜面時HC2隨著鈮厚度轉變，HC2與溫度的關係會有二維到三維的特性改變，維度轉換大概的範圍坐落在100nm~130nm間，這也是界面效應的影響；而磁場垂直膜面的量測可讓我們定義出超導的相干長度。後一個部份是電流垂直膜面(CPP)量測，可以直接給我們介面電阻的相關訊息，因為幾何因素電阻值會是CIP量測的百萬分之一倍，所以我們利用超導量子干涉儀(SQUID)作為皮伏特計(pico-volt meter)。我們有四組樣品，利用基本的線性分析可以得到四個物理量，分別是：超導態鈮與鎳的介面電阻(ARS/F)、正常態鈮與鎳的介面電阻(ARN/F)、鎳的電阻率(ρNi)以及正常態鈮的電阻率(ρNb)。由我們的分析得知，介面效應的強度除了磁性層的交換場大小，也與超導/鐵磁間電子波函數的傳輸透明度有關，而此能障(barrier)是由介面電阻來主導，因此我們可藉以上量測來定性及定量的分析鈮/鎳系統的介面效應。We have studied the proximity effect in superconduct Nb / ferromagnetic Ni (S/F) multilayer system. The superconducting critical temperature (Tc) variation of F/S/F trilayer samples with fixed Ni thickness (dNi) and varied Nb thickness (dNb) were measured by conventional current-in-plan (CIP) measurement. As the dNb was reduced below 100 nm, the Tc rapidly decreased monotonically. The critical thickness, below which superconductivity vanishes, with fixed dNi was derived by fitting the data in terms of proximity theory. We got a critical thickness of Nb about 40nm when sandwiched in 50nm of Ni, below this thickness there is no superconductivity even if our samples were cooled down to 0.3K. ccording to the Ginzburg-Landau (G-L) equation, the upper critical magnetic field (HC2) is a function of temperature (T). We changed the dNb to see how the dimension of Nb thin film affected the HC2(T) behavior. From our results, the 2-dimensional to 3-dimensional crossover was about 100~130nm for Nb/Ni multilayers. The superconductivity was strongly suppressed due to the pair-breaking effect from the Ni film. Even though the thickness of Nb was larger than perpendicular coherence length, the HC2 had square-root behavior dependence on T.urrent-perpendicular-to-plan (CPP) measurements provide us quantitative information about the interfacial resistance between Ni and Nb with either superconducting or normal (N) states in the S/F heterostructure. To fit the data simultaneously we had used a global fit technique and the results showed that the interface resistance of Ni and Nb, which was in superconducting and normal state, were about 4.2 fΩ-m2 and 1.5 fΩ-m2 respectively. The interface transparency parameter γB was related to the normal state interface resistance and we calculated γB ~2.1.摘要 Ibstract III錄 V目錄 IX目錄 XIII一章 簡介 1-1 文獻回顧 1-2 實驗動機 6二章 原理介紹 7-1 超導現象簡介[8] 7-2 London穿透深度(London penetration depth)[10] 10-3 Ginzburg-Landau (GL)理論[11] 11-4 基本的BCS超導理論[8] 13-5 超導電流的穿隧效應(Tunneling Effect) 16-6 第二類超導體[8] 19-7 超導(SC)/鐵磁(FM) 邊際效應擬合原理[7] 22-8 Pippard模型[13],[14] 23三章 儀器設備與實驗原理 24-1 濺鍍機(Sputter) 24-1-1 濺鍍原理 24-1-2 鍍膜環境控制。 25-1-3 磁控濺鍍。 26-1-4 濺擊產生率(S) 28-1-5 濺鍍系統。 29-2 真空排氣系統 29-2-1 抽氣流程 29-2-2 冷凍幫浦原理與簡易故障排除 30-2-3 真空計 31-3 超導量子干涉元件 (Superconducting quantum Interference Device) 31-4 物理特性量測系統 (Physical Properties Measurement System) 31-4-1 溫控 32-4-2 磁場控制 32-5 磁性量測系統 (Magnetic Properties Measurement System) 34-6 皮伏電壓計 (SQUID-based Pico-volt meter) 36-7 X-Ray 36-8 能量分布光譜儀 (Energy Dispersive Spectrum) 38-9 膜厚粗鍍儀 (Alpha Step Profilometer)[15] 39-10 薄膜形成的物理機制 40-10-1 原理簡介 40-10-2 薄膜成長的三種模式： 42-11 電流平行膜面量測(CIP) 43-12 電流垂直膜面量測(CPP) 44-12-1 CPP電阻公式 45-12-1-1 正常態CPP樣品[Ni(dNi)/Nb(dNb)]N/Ni(dNi)總電阻公式： 46-12-1-2 超導態樣品[Ni(dNi)/Nb(dNb)]N/Ni(dNi)的電阻公式 46-12-2 單位面積電阻的表示 46-12-3 CPP與CIP電阻量測比較 47四章 實驗步驟： 49-1 樣品準備 49-1-1 CIP樣品的製備： 49-1-2 CPP樣品的製備： 50-2 樣品量測 51-2-1 CIP樣品的電性量測 51-2-2 CIP樣品HC2的測量 51-2-3 CPP樣品垂直膜面的電流量測 52-2-4 CIP樣品的磁性量測 52五章 實驗數據與分析 54-1 鎳薄膜基本特性量測 54-2 CIP鎳電阻率測量 54-3 CIP電性量測 56-4 CIP HC2的量測 59-5 CPP介面電阻量測 70-5-1 [Ni(57.9nm/Nb(107.4nm)]x/Ni(57.9nm) 71-5-2 [Ni(77.7nm/Nb(11.5nm)]x/Ni(77.7nm) 72-5-3 [Ni(dNi)/Nb(27.2nm)]7/Ni(dNi) 73-5-4 [Ni(77.5nm/Nb(dNb)]7/Ni(77.5nm) 74-6 Global Fit 76-6-1 Global Fit簡介[34] 76-6-2 兩個參數(2-parameters) Global Fit 76-6-3 三個參數(3-parameters) Global Fit 77-6-3-1 77-6-3-2 79-6-4 四個參數(4-parameters) Global Fit 82-7 CIP 鈮鎳多層膜磁特性量測 85六章 結果與討論 91考文獻： 95錄Ⅰ 97錄Ⅱ 99錄Ⅲ 10
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
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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