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CMS Virtual Visit from Taiwan - 30 July 2015
No full textGuides: Chia-Ming Kuo, Wei-Yin Liu, Pen-Hsuan Wang, Cheng-Wei Ye
The Applications of Fiber Bragg Grating Sensors in the Transient Strain Measurements of Structural Components Under Impact Loadings
No full text光纖具有優良的機械性質、高靈敏度，以及不受電磁干擾等優點，促使了光纖感測技術的研發在近年來蓬勃發展。尤其以布拉格光纖光柵感測器最為受到重視，其在靜態與低頻的動態量測能力已受到肯定，且有大量應用在各種工程結構量測的成功實例，不過對於高頻及暫態方面的量測能力，還有待進一步的研究與開發。 在布拉格光纖光柵的理論分析上，本文利用模態耦合理論探討反射頻譜響應，模擬布拉格光纖光柵在靜態與動態應變場下的行為特性，顯示感測靈敏度隨著頻率增加而下降，以及增加應變頻率與振幅會造成感測訊號失真的現象，並建立失真臨界的概念，探討布拉格光纖光柵的動態感測範圍與限制，可作為實際應用時的參考依據。 在布拉格光纖光柵的實驗量測上，本文利用本實驗室開發的能量調變感測系統，針對各種結構件承受動態撞擊負載而產生的暫態波傳訊號進行應變量測，包括直立圓桿構件、中空圓管構件及懸吊鋼索構件，也和應變規進行同步量測並相互比較。此外再分析實驗結果的頻譜響應，並和理論及有限元素法相互對照，多方驗證了布拉格光纖光柵感測器優異的動態應變量測能力，也對結構件的暫態波傳特性有所了解並建立相關應用。Recently, the optical fiber sensing technologies, especially fiber Bragg grating (FBG) sensors, have been rapidly developed due to the advantages such as excellent mechanical properties, high sensitivity and electromagnetic immunity. The measurement ability of FBG sensors in static and low frequency responses has been demonstrated, and there are many successful engineering applications. However, further investigations are needed for FBG to improve the measurement ability in high frequency and transient responses. In the theoretical analysis of FBG, the coupled-mode theory is used to present the reflected spectra and to simulate the responses under static and dynamic strain fields. The results indicate that the sensitivity declines with the increase of input frequency and the increase of frequency and amplitude of strain result in signal distortion. The concept of distortion that limit the practical applications is established to discuss the dynamic sensing range of FBG. In the experiments of FBG, the power modulated sensing system is established to measure the transient responses of dynamic strain for structural components under impact loadings, which include solid rod, hollow tube and suspended cable. The strain gage is also used to measure simultaneously with the FBG sensors to compare the results obtained from two different techniques. In addition, the frequency spectra of experimental results are analyzed and compared with theory and finite element method. According to the available results, it is proved that FBG sensors have excellent ability for dynamic strain measurement. At the same time, the transient wave propagation properties of structural components are analyzed in detail and the associated applications are established.摘要 Ibstract II錄 III目錄 VII目錄 IX一章 緒論 1-1 研究動機 1-2 文獻回顧 4-3 論文內容簡介 7二章 光纖及光纖光柵之基本原理 9-1 基本光纖光學 9-2 光纖光柵基本原理 11-3 光纖光柵之分類 12-3-1 短週期式光纖光柵 13-3-2 長週期式光纖光柵 13-4 光纖光柵之製作 14-5 光彈效應與熱光效應 18-5-1 光彈效應 18-5-2 熱光效應 21-6 共振波長飄移理論 22-6-1 共振波長飄移原理 22-6-2 平面應力下之情況 24-6-3 單軸向應力下之情況 25三章 布拉格光纖光柵之模擬與分析 31-1 模態耦合理論 31-2 基本頻譜特性 35-3 靜態應變場下之頻譜響應 36-4 動態應變場下之頻譜響應 37-4-1 步階函數應變波傳 37-4-2 穩態正弦函數應變波傳 38四章 直立圓桿構件之暫態應變量測 64-1 圓桿共振頻率之理論與數值解析 64-1-1 縱向伸展模態 64-1-2 橫向彎曲模態 65-2 訊號分析工具之基本理論 67-3 能量調變型光纖光柵量測系統 68-4 實驗架設說明 69-5 實驗儀器設備與元件 70-5-1 寬頻光源 71-5-2 光隔離器與光環行器 71-5-3 濾波器 71-5-4 光耦合器 71-5-5 光頻譜分析儀 72-5-6 光二極體 72-5-7 應變規信號制約放大器 72-5-8 示波器 73-6 實驗結果與頻率分析 73五章 中空圓管構件之暫態應變量測 107-1 中空圓管共振頻率之理論與數值解析 107-1-1 縱向伸展模態 107-1-2 橫向彎曲模態 107-2 實驗架設說明 108-3 實驗結果與頻率分析 109六章 懸吊鋼索構件之暫態應變量測 135-1 鋼索共振頻率之理論與數值解析 135-2 鋼索受撥擊實驗 136-2-1 實驗架設說明 136-2-2 實驗儀器設備與元件 136-2-3 實驗結果與頻率分析 137-3 長度200mm之鋼索受撞擊實驗 139-3-1 實驗架設說明 139-3-2 實驗結果與頻率分析 140-4 長度280mm之鋼索受撞擊實驗 141-4-1 實驗架設說明 141-4-2 實驗結果與頻率分析 141-5 弦與梁之共振特性探討 143-6 光纖受撥擊實驗 144-6-1 實驗架設說明 144-6-2 實驗結果與頻率分析 144-7 鋼索張力量測實驗 146-7-1 實驗架設說明 146-7-2 實驗結果與頻率分析 147-8 存在缺陷之鋼索受撞擊實驗 148-8-1 實驗架設說明 148-8-2 實驗結果與頻率分析 148-9 鋼索斷裂實驗 149-9-1 實驗架設說明 149-9-2 實驗結果與討論 150七章 結論與未來展望 203-1 結論 203-2 未來展望 204考文獻 206錄A 色散偏移光纖規格 212錄B 光敏光纖規格 214錄C 寬頻光源特性 215錄D 光頻譜分析儀規格 216錄E 光二極體規格 218錄F 應變規信號制約放大器規格 219錄G 示波器規格 221錄H 應變指示器規格 22
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
Plastic tribute to Van Gogh
No full text(Signalé par notre collègue Cecilia Montero, Cf. Shangai Daily du 11 mai 2016) More than 4 million plastic bottles are positioned to recreate Vincent van Gogh’s famous painting The Starry Night at the Embrace Cultural and Creative Park in Keelung, Taiwan. The mosaic, titled The Starry Paradise, covers 53 hectares and opened to the public last month to mark the 125th anniversary of the Dutch painter’s death. Wang Cheng-wei, the artist responsible for the creation, collected the bottles from r..
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
Talar Osteosarcoma Treated with Limb-Sparing Surgery: A Case Report
No full textOsteosarcomas commonly occur in the metaphyses of long bones , such as the femur, tibia, and humerus1, whereas only about 1% involve the bones of the foot2. Approximately 75% of osteosarcomas of the foot arise in the calcaneus or metatarsals1. Osteosarcoma of the talus is very rare. Amini and Colacecchi first reported such a case in 1980 and treated the patient with an above-the-knee amputation3
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