1,720,963 research outputs found
Segregation and Diffusion of Au Films on NiAl(100)
No full text本論文中主要的工作，是利用AES (Auger Electron Spectroscopy)、TPD (Temperature Programmed Desorption)等表面科學方法，來研究金(Au)吸附在鎳鋁合金(100)表面後，經由退火(Annealing)處理，產生的擴散(Diffusion)，熱脫附(Thermo Desorption)之現象。本研究中的AES量測，運用了本實驗室所開發的gating技術，改良了傳統AES方法，使我們可以在運用程式控溫加熱的過程中，同時進行AES之量測，此實驗方法我們稱之為”程式控溫Auger電子能譜(Temperature Programmed Auger Spectra)”，簡稱為TPA。藉由控溫量測Auger電子之訊號強度變化，我們發現金在鎳鋁合金(100)表面上，當溫度升高到超過1000K之後，金的AES訊號強度會大幅下降中，此時再降溫到800K，金AES訊號又會慢慢回升到某一程度之後維持住。於是，我們進行了一系列的TPA實驗，以了解金在鎳鋁合金(100)表面上加熱後的表面擴散(Surface Diffusion)、塊材內部擴散(Bulk Diffusion)、表面重新覆蓋(Surface Segregation)等行為。同時，我們也運用了一些線性代數的數學運算，對Auger能譜進行分析，使我們可以得到更細微的資訊。摘要.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..1
目錄.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..2
1. 簡介.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..4
參考資料 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..8
2. 實驗儀器與分析工具 .. .. .. .. .. .. .. .. .. .. .. .. ..9
2.1 超高真空系統與分析工具.. .. .. .. .. .. .. .. .. .. ..9
2.2 程式控溫熱脫附 (TPD).. .. .. .. .. .. .. .. .. .. .. ..11
2.3 程式控溫Auger電子能譜 (TPA) .. .. .. .. .. .. .. .. ..13
參考資料 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..16
3. 線性代數分析.. .. .. .. .. .. .. .. .. .. .. .. .. .. ..17
3.1 向量空間之自由度.. .. .. .. .. .. .. .. .. .. .. .. ..17
3.2 以Auger能譜為基底之展開式.. .. .. .. .. .. .. .. .. ..21
4. 實驗程序.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..23
4.1 TPD實驗.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..23
4.2 AES與TPA實驗.. .. .. .. .. .. .. .. .. .. .. .. .. ..24
5. 結果與討論.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..27
5.1 金在鎳鋁合金(100)表面的熱脫附現象.. .. .. .. .. .. ..27
5.2 程式控溫Auger電子能譜(TPA).. .. .. .. .. .. .. .. ..30
5.3 Auger訊號的分解.. .. .. .. .. .. .. .. .. .. .. .. ..42
參考資料.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..54
6. 結論.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..55
7. 附錄.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..56
7.1 金/鎳鋁合金(100).. .. .. .. .. .. .. .. .. .. .. .. ..56
7.2 銀/鎳鋁合金(100)&銀/氧/鎳鋁合金(100) .. .. .. .. .. 62
誌謝.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..6
Low-kilovolt Coherent Electron Diffractive Imaging Based on a Single-Atom Electron Source
No full text在這項工作中，我們建造了一個使用單原子電子源的低能量同調電子繞射成像顯微鏡。它包括一個單原子場發射源，一組三極式的靜電透鏡、結合奈米尺度步進器的樣品台，和一個可前後移動之延遲線偵測器，使用此偵測器可以在樣品後方不同距離記錄繞射圖案。此顯微鏡的設計非常適合對3奈米厚度以下的極薄樣品進行成像。我們分析了其中用於聚焦電子束的非對稱三極式靜電透鏡，並以2千電子伏特的電子能量在樣品平面取得直徑為87奈米的聚焦束斑。利用此儀器，我們成功地記錄到對應0.62埃解析度的石墨烯樣品高角度繞射圖案，我們同時進行了數值模擬，並以此模擬結果與實驗結果進行比對。這項工作展示了操作電壓在1-10千伏時，同調電子繞射成像術在超薄二維材料、生物分子和奈米材料等方面的潛力。該儀器的最終目標是取得這些材料的高對比、原子解析度影像。In this work, a transmission-type, low-kilovolt coherent electron diffractive imaging instrument was constructed. It comprised a single-atom field emitter, a triple-element electrostatic lens, a sample holder, and a retractable delay line detector to record the diffraction patterns at different positions behind the sample. It was designed to image materials thinner than 3 nm. We analyzed the asymmetric triple-element electrostatic lens for focusing the electron beams and achieved a focused beam spot of 87 nm on the sample plane at the electron energy of 2 kV. High-angle coherent diffraction patterns of a suspended graphene sample corresponding to (0.62 Å)-1 were recorded. The simulated results were calculated to compare with the experimental results. This work demonstrated the potential of coherent diffractive imaging of thin 2D materials, biological molecules, and nano-objects at voltage between 1-10 kV. The ultimate goal of this instrument is to achieve atomic resolution of these materials with high contrast and little radiation damage
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
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