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A Study on Tin Dioxide Nanoparticles for Gas Sensing
No full text本研究之目的在探討一氧化碳經由不同的二氧化錫奈米顆粒體為感測材料與金梳狀電極為載體之低溫感測器試製與感測特性鑑訂。所建構之氣體偵測器具備歐姆阻抗。利用溶膠-凝膠合成法所製備之二氧化錫奈米顆粒其平均直徑為20nm至50nm。用TEM與XRD檢測感測膜時顯示出二氧化錫奈米顆粒為多晶結構且每個晶粒形狀為矩形，環狀SAD檢測圖形顯示出二氧化錫奈米顆粒體屬於多晶結構。構裝後，實驗所量測輸出之訊號顯示一氧化碳感測訊號靈敏度明顯受操作溫度影響，在350℃時達極大值。平衡輸出訊號與一氧化碳濃度(20-100 ppm）呈線性關係，且由此關係可得一校正曲線。當摻雜鈀(3.5wt %)在二氧化錫奈米顆粒體時，能使感測靈敏度提高約50%，這可能是因為摻雜負電性較錫略高之鈀導致一些缺陷產生在二氧化錫多晶結構上，如此增加更多可用的活位。這些活位能夠與更多氣體分子產生交互作用，因此訊號輸出增加。This thesis reports investigates on CO sensing due to different sizes of SnO2 nanoparticles as probing material. that were coated on a substrate of comb-type Ag electrode. Sol-gel was synthesized to imbed tin-dioxide nanoparticles with average diameter in a range of 20-50 nm. A gas detection instrument system incorporating our sensing element was set-up for performance evaluation based on signal output implementing the ohmic resistance. Transmission electron spectroscope and X-ray diffraction investigations indicated that the SnO2 nanoparticles grown by sol-gel synthesis process formed crystal clustering of rectangle-like. The scattered ring pattern further confirmed that the SnO2 nanoparticles belonged to polycrystalline structure. Performance test showed that the CO sensing signal sensitivity is obviously influenced by operating temperature, and the optimum condition appeared at 350 °C. A linearity output in respond to CO concentration between 20 and 100 ppm was obtained. This shows that it can be served as a calibration curve. Pd (3.5 wt %) doped into SnO2 nanoparticle clusters was shown to increase in sensitivity of approximately 50%. This is presumably duo to the fact that the more electronegative Pd created some defects in SnO2 polycrystals, thus creating more available active sites for CO sensing and enhanced signal condition.誌謝 …ii
摘要 ...iii
Abstract ...iv
圖目錄 ...vii
表目錄 ...ix
符號說明 …x
第一章 緒論
1-1 前言 …1
1-2 研究動機與目的 …3
第二章 文獻探討
2-1 分子反應動力學理論 …5
2-2 氣體感測器原理與種類 …13
2-3 奈米材料簡介 …28
2-4 奈米微粒簡介 …31
2-5 奈米顆粒體的製備方法 …32
2-6 二氧化錫的材料性質 …36
2-7 半導體式氣體感測器的工作原理 …38
2-8 影響感測性質之因素 …50
2-9 溶膠-凝膠法 …54
2-10 旋轉塗佈法的原理 …58
2-11 設計方法論 …59
第三章 材料與方法
3-1 實驗藥品 …66
3-2 製備SnO2凝膠 …66
3-3 電極與感測器之製備 …68
3-4 感測電路 …69
3-5 樣品之基本物性分析 …70
3-6 氣體感測實驗 …71
第四章 結果與討論
4-1 溶膠凝膠法-製程 …74
4-2 數據分析 …74
4-3 感測溫度對靈敏度的影響 …77
4-4 氣體濃度對感測度的影響 …78
4-5 催化劑的作用對感測靈敏度之影響 …80
第五章 結論與建議
5-1 結論 …83
5-2 建議 …83
參考文獻 …8
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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