1,720,991 research outputs found
Dynamic Data Acquisition and Parameters Estimation for Traffic Prediction
No full text16th World Congress on ITS, Stockholm, Sweden, Sep.20-25, 2009.This study proposes a real-time traffic data acquisition system and prediction algorithm. The framework of the system suggests taxi fleets as probe vehicles, combining roadside detectors to collect data from urban networks extensively. Then, mathematical models of “link travel time prediction” and “route flow estimation” are built based on generalized least squares and extended Kalman filter. To verify the prediction capability of the models, this study analyzed the results from grid network simulation. The models are proven well functioning with data processing and calibration. The mean errors of flow estimation on the generated network traffic flows are within 15%
Promoting an Information Service Provider as a Core Operational Firm for ITS Deployment
No full text6th Asia Pacific ITS Forum, Taipei, Taiwan, Oct.6-9,200
An inquiry into the food web and operational model of 248 farmers' market
No full text全球食物供應不穩定的現象，使許多國家開始重視在地糧食系統，以保障食物的生產及供應安全，台灣過度依賴進口農產品及對小農不利的農業政策，促使地方農業運動逐漸在各地萌芽發展，而農夫市集直接串連產銷關係，在短時間內受到公私部門的重視，陸續發起市集運動，以解決小農生計的問題。本研究以台北248農學市集作為個案研究對象，透過參與式觀察及訪談了解248農學市集的發展與推廣方式如何協助小農解決問題。
研究結果發現248農學市集是由一群具有相同的理念的生產者所建立而成的市集，市集作為推廣在地小農理念、價值觀及農產品的平台，讓生產者與消費者面對面溝通，提供消費者無毒、安全的食物外，並教育消費者對食物多元的了解，一方面以消費支持友善的種植方式間接友善環境，並支持生產者的理念與價值觀，同時也拉近都市與鄉村的連結，加深人、食物與土地之間的關係，農夫市集的發展協助農友拓展多元的合作機會，改變生產者的角色，建立比有機認證更有保障的信任關係。The unstable global phenomenons begun to attach global food system, we need to protect the safety of food production and supply. Taiwan excessive dependence on imports of agricultural products and disadvantage agricultural policy to small farmers, both to promote local agriculture movement has gradually blossomed and developed in various places.Farmers’ marke direct serial production and sales parts, be attention to both public and private sectors in a short time. Initiated market movement successively to solve the problem of small farmers’ livelihoods. I select 248 Farmers’ Market to be this case study, through participant observation and interviews to understand the development and how to solve small farmers’ problems.
The results showed that the farmers in 248 Farmers’ Market is grouped and established by the same idea, It’s be a place to promotion local small-scale ideas, agricultural products and values, so that the producers and consumers communicate face to face. On the one hand, 248 Farmers’ Market not only to provide non-toxic, freash and safe food but also to educate consumers the knowledge of food, on the other hand, consumers direct support the farmer’s cultivation methods, indirectly support the environment and support producers of beliefs and values, as well as closer links to urban and rural areas, deepen the relationship in people, food and land.
We can actually know that farmers’ market can help farmers to expand the diverse of cooperation chance, change the role of producers and create more trust relationships than the organic certification
Biochemical Studies on the Aspartate Aminotransferase from Deinococcus radiodurans R1
No full text耐輻射奇異球菌（Deinococcus radiodurans R1；D. radiodurans R1）對於環境中的游離輻射、UV輻射與過氧化氫的抵抗力極高。瞭解D. radiodurans R1所擁有的特殊分子及生理層次可以幫助我們認識生物體應對輻射傷害而發展的耐受機制。本研究主要為探討耐輻射奇異球菌之天門冬胺酸轉胺酶 (Aspartate Aminotransferase；AspAT；EC 2.6.1.1）的各項性質。
天門冬胺酸轉胺酶也稱為麩胺酸-草乙酸轉胺酶（Glutamate Oxaloacetate Transaminase；GOT）。它催化麩胺酸與天門冬胺酸之間的轉胺反應，與氮的循環以及能量利用有密切關係。在耐輻射奇異球菌中，AspAT的基因稱為aspC，約1167 bp，轉殖於大腸桿菌進行表現之後，使用金屬親和性層析 ( Ni-NTA affinity chromatography ) 純化達到均質。再以Factor Xa切除Fusion Protein ( Maltose-binding Protein )，並由第二次的金屬親和性層析純化得到DrAspAT。此時蛋白質的比活性為104.6 U/mg。以逆相HPLC去除二次純化後均質所含鹽類，經質譜儀測定分子量，其值與理論值完全相符。
DrAspAT與PcAspAT (豬的細胞質)都有明顯耐熱性，至80 ℃依然還有50 % 的殘留活性。然而在X-ray輻射試驗中，DrAspAT顯示出較強的耐輻射性，且兩酵素的損害程度皆與成濃度反比。
另一方面，利用Program O模擬DrAspAT的結構以預測DrAspAT結構中重要殘基的分布，選取其中六個殘基進行定點突變，所得的突變株經酵素分析後結果都無活性殘留，證實此一模擬的結構可信度極高。
模擬所得DrAspAT結構相較於嗜中溫生物體之AspAT而言，大體相似。然而在N端的序列結構與辨認酸性基質殘基的改變，顯示出兩類生物在演化上的分歧。比對序列後發現，組成酵素的胺基酸成分似乎與其生存環境相關。DrAspAT序列中有高比例可加強構造穩定性的Proline殘基以及不含易使酵素分子被含氧自由基攻擊的Cystein 殘基存在。
透過DrAspAT的生化研究，再加上目前可獲得的研究資訊，可以一窺耐輻射奇異球菌生存策略與蛋白質分化機制的奧秘。Deinococcus radiodurans R1 is well-known for its extraordinary resistance against high-dose ionizing radiation, UV radiation and hydrogen peroxide. It is an ideal target for the study of survival strategies adopted by extremophiles under various harsh environmental conditions. This thesis aims at the characterization of an enzyme, aspartate aminotransferase (AspAT, EC 2.6.1.1), from D. radiodurans R1.
Aspartate aminotransferase, also known as glutamate oxaloacetate transaminase (GOT), catalyzed the interconversion between glutamate and aspartate. It is involved in the metabolism of nitrogen-containing biomolecules and is essential for energy metabolism. In D. radiodurans R1 AspAT is encoded by the gene aspC of about 1167 bp. AspAT from D. radiodurans R1 has been cloned, expressed in E. coli, purified and characterized. The expressed recombinant protein was purified to apparent homogeneity by Ni-NTA affinity chromatography. The fusion protein (Maltose-binding Protein) was removed by Factor Xa. The cleavage product was further purified by Ni-NTA column again to yield a homogeneous protein. Its molecular mass was confirmed by mass spectral analysis after desalting by reversed-phase HPLC through a C8 column. The purified protein had a specific activity at 104.6 U/mg. This enzyme, designated as DrAspAT, exhibits remarkable thermal tolerance and radioresistance, as compared with AspAT from porcine cytoplasmic. The radioresistance is dependent on protein concentration： the higher the protein concentration, the less damage caused by X-ray.
The molecular structure of DrAspAT was modeled by using Program O and a template structure of Thermus thermophilus AspAT (1bjw; TtAspAT ). Several catalytically important residues have been indenfied from the modeled strucute. In order to test the modeled structure site-directed mutagenesis experiment was carried out on those important residues. The results showed that all the mutant enzymes lost the enzymatic activity, thus confirming the important roles they play in catalysis.
Sequence alignment and analysis showed that DrAspAT is similar to the AspATs from mesophilic organisms in conformation. However, the comparison result showed evolution diversity between those two kinds of AspATs by the obvious difference in the N-terminal sequence and the residues recognizing the distal carboxylate group of the substrate. Moreover, by advanced analysis for the composition of amino acids, DrAspAT contain higher percentage of proline residues and no cysteine in contrast to other mesophilic counterpars, this preference of DrAspAT may partially account for its remarkable structural stability.
As a result, analysis for biochemical studies on DrAspAT with other data about AspATs from various species could give us some clues about extraordinary radioresistance of D. radiodurans R1 and evolution direction of proteins.表目錄.. 5
圖目錄.. 6
摘要.... 8
Abstract 9
第一章 緒 論 11
第一節 轉胺酶總論 11
一 轉胺酶 11
1. 轉胺作用 11
2. 轉胺酶分類 13
二 天門冬胺酸轉胺酶 15
1. 分類 15
2. 功能 16
3. 催化機制 16
4. 結構 19
第二節 耐輻射奇異球菌 21
一 前言 21
二 適應性輻射演化 21
1. 普遍適應 22
2. 環境改變 22
3. 群島效應 22
三 嗜極菌 22
四 耐輻射奇異球菌發現歷史 23
五 耐輻射奇異球菌生理構造與遺傳物質 23
六 耐輻射性 25
1. 基因體 25
2. 物理防護 26
3. 金屬離子 26
第三節 研究目的與研究流程 28
一 應用 28
1. 製備胺基酸及胜肽 28
2. 藥物 28
3. 廢料清除 28
二 研究目的 29
1. DrAspAT定性 29
2. AspAT比較 29
3. DrAspAT之功能性殘基確認 29
4. 耐輻射奇異球菌抗輻射性的相關因子 29
三 研究流程 30
第二章 天門冬胺酸轉胺酶表現純化與特性分析 31
第一節 前言 31
第二節 材料與方法 34
一 聚合酵素鏈鎖反應 34
二 限制酶切反應 35
三 接合反應 36
四 轉形反應 36
五 DrAspAT表現 37
六 超音波破菌 37
七 蛋白質膠體電泳分析 38
八 鎳金屬親和管柱層析分析 39
九 接合蛋白質切除反應 40
一〇 蛋白質定量分析－Bradford法 40
一一 活性分析－MDH-coupling assay 41
一二 高壓液相層析與質譜分析 42
一三 西方點墨法 42
一四 熱穩定性試驗 43
一五 儲存條件試驗 43
一六 基質專一性試驗 44
一七 X-ray 輻射試驗 44
第三節 結果與討論 45
一 結果.. 45
二 討論.. 60
1. aspC基因轉殖 60
2. DrAspAT之表現 60
3. DrAspAT之純化 60
4. DrAspAT確認 61
5. 儲存條件 61
6. 基質專一性分析 62
7. 熱穩定性 62
8. X-ray 輻射耐受性 63
第三章 天門冬胺酸轉胺酶比對與分子模擬 64
第一節 前言 64
第二節 原理與方法 66
一 天門冬胺酸轉胺酶之比對分析 66
二 同源分子模擬 67
1. 原理 67
2. 方法與步驟 67
三 DrAspAT定點突變 68
第三節 結果與討論 69
一 結果 69
二 討論 76
1. AspATs 比對分析 76
2. 分子模擬 77
3. 突變酵素分析 77
第四章 結 論 與 展 望 78
第一節 DrAspAT之生化研究 78
第二節 DrAspAT之結構分析 79
第三節 展望 80
附錄一：儀器設備一覽表
附錄二：縮寫表
參考文
Study on Real-Time Traffic Data Acquisitions and Algorithms for Parameters of Traffic Flow
No full text為達到先進運輸管理系統之運作，本研究提出一即時交通資訊擷取系統，規劃以計程車車隊為主體之探測車系統，結合路側偵測系統，以對於都市地區路網系統進行廣泛而完整之交通資訊擷取，並研擬系統運作下之資料庫系統設計。根據此一資料系統架構之下，考量資料項目之取得，本研究分別建構「路段旅行時間預測」和「動態旅次OD推估」之數學模式，並以廣義最小平方法和推廣卡爾曼濾波器進行模式之演算，對於路網系統之車流狀態進行預測，藉以支援相關動態交通控制、管理之決策。
在模式驗證部分，本研究係透過Paramics軟體模擬一般化棋盤型路網系統下之交通車流，對路段旅行時間預測模式之預測結果進行分析，研究中主要藉由準確度、強健性和穩定性三個面向評估模式之預測能力。預測結果顯示，經由模式校估以及來源資料之處理過程，可得到優良之預測結果表現。對於動態旅次OD推估模式亦根據同樣的模擬結果進行試算之流程，將推估所得之旅次OD流量反應於路段流量上可得到良好之預測結果，是以評估模式之推估結果為合理。
根據預測誤差，探討探測車回傳資料對於整體車流之代表性在模式預測準確度之影響，分析結果顯示，在車流中探測車佔有率達到5%以上，本研究所提出之路段旅行時間預測模式即可反應良好之預測能力。In order to establish an advanced traffic management system (ATMS), this study proposes a real-time traffic data acquisition system. The framework of system has its basis of taxi fleets as probe vehicles, and combines roadside detectors to collect traffic data from urban network extensively. According to the physical architecture, the study builds the mathematic models of “travel time prediction for road section” and “dynamic OD estimation”. The algorithms are based on generalized least squares (GLS) and extended Kalman filter (EKF) respectively. Through the prediction model, the traffic flows at various conditions are predicted to support decision-making of traffic control and management.
To verify the models, for travel time prediction, this study analyzes the prediction results of grid network simulation from the Paramics, which is a traffic simulation package, and evaluates prediction capability by indices of precision, robustness and stability. The model proves a good prediction resulting in data calibration and processing. For the dynamic OD estimation, the study estimates traffic volume from predicted OD flows, which generates the mean error is within 10%. Accordingly, it concludes that the model is reasonable. Also, considering the representation of probe vehicles in the traffic flow, the model has good prediction capability, when the proportion of probe vehicles is above 5% of all vehicles.第一章 緒論 1
1.1 研究背景與動機 1
1.2 研究目的與範圍 2
1.3 研究方法 3
1.4 研究內容與流程 4
1.5 論文章節說明 6
第二章 文獻回顧 8
2.1 探測車輛於交通資料擷取系統之應用與相關研究 8
2.2 旅行時間預測方法 10
2.3 動態旅次OD推估問題 12
2.3.1 指派依據之動態旅次OD推估方法 13
2.3.2 非指派依據之動態旅次OD推估方法 16
第三章 方法論 19
3.1 最小平方法 19
3.1.1 基本關係式 19
3.2 卡爾曼濾波理論 21
3.2.1 系統基本描述 21
3.2.2 卡爾曼濾波器之求解 24
3.2.3 推廣卡爾曼濾波器 28
第四章 市區棋盤型路網環境下之交通資訊擷取系統 31
4.1 路網環境與實體系統架構 31
4.2 即時交通資訊擷取系統 32
4.2.1 主動交通資訊擷取 32
4.2.2 被動交通資訊擷取 35
4.3 資料庫系統與模式演算架構 37
第五章 市區棋盤型路網環境下動態旅行時間預測與旅次OD推估模式之建立 42
5.1 動態旅行時間預測模式 42
5.2 動態旅次OD推估模式 46
5.2.1 數學模式建構 47
5.2.2 系統演算流程 50
第六章 模式驗證與數值分析 54
6.1 模擬資料背景說明 54
6.1.1 Paramics V4.0基本介紹 55
6.1.2 路網與車流資料設定 56
6.2 動態路段旅行時間預測模式之校估與驗證 59
6.2.1 評估指標說明 60
6.2.2 模式校估與演算 61
6.2.3 背景資料處理與分析 68
6.2.4 敏感度分析與探測車佔有率之探討 72
6.3 動態旅次OD推估模式之數值演算 76
6.3.1 路網下旅次OD系統與路徑流系統 76
6.3.2 案例演算 79
6.3.3 演算結果分析 81
第七章 結論與建議 84
7.1 結論 84
7.2 建議 87
參考文獻 8
Establishment and Evaluation of Ca9-22 Cell Platform for Screening Food Factors with Anti-oxidative Potential
No full text自由基 (Free radicals) 在細胞中可擔任訊息傳遞介質以維持細胞的正常運作，但是過高的自由基會導致氧化壓力產生，而許多疾病的進程已被證實與氧化壓力有相關聯性，因此找尋潛在抗氧化能力的食材是目前重要的研究課題。抗氧化活性評估方法，不外乎利用體外試管實驗，例如清除DPPH (1,1-diphenyl-2-pricrylhydrazyl)自由基能力、還原力測定等，但是這些分析方法僅是針對消除某幾種特定自由基所設計，且為單純化學反應的評估，無法正確反應生物體的狀況；若以動物體為模式，則消耗時間、金錢、人力且違反3R (Replace, Reduce, Refine) 原則，因此發展一個可快速大量篩檢且即時偵測抗氧化能力的細胞平台是必要的。首先，利用生物技術方法建立一個含有抗氧化反應 (Antioxidant responsive element, ARE) 與分泌型報導基因 (Secretory luciferase reporter gene) 的質體，運用PCR與DNA定序等方式確認其質體的建立後，將其轉殖入人類舌癌細胞Ca9-22中，以抗生素400 μg/mL Neomycin篩選成功轉殖的細胞株。當待測物誘發轉錄因子--NF-E2相關因子二 (Nuclear factor-erythroid 2-related factor-2) 轉運至核內並結合到ARE片段上，將會啟動下游報導基因的轉錄及轉譯，藉由收集培養液即時偵測Nano-Glo Luciferase冷光蛋白的表現量，以代表待測物能誘發抗氧化的能力。本研究已成功建立此細胞平台，並已確認其穩定度與靈敏度，將來可以利用此細胞平台作為抗氧化潛力食材因子的篩選工具。Reactive oxygen species (ROS) act as signaling intermediates for many normal cellular processes, but elevated ROS has been linked to over 150 diseases, including atherosclerosis, diabetes, cancer, and neurodegenerative diseases. These free radicals generated from living body or environment are sources of oxidative stress. Severe oxidative stress leads to DNA damage or/and cell death. Nuclear factor-erythroid 2-related factor-2 (Nrf2) is a key transcription factor that plays a central role in cellular defense against oxidative and electrophilic damages by induction of anti-oxidative enzymes, including heme-oxygenase 1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO1). The objective is to establish a cell platform to screen food factors with potential anti-oxidative function. Our strategy is to construct a plasmid that contains antioxidant responsive element (ARE) driven promoter and secretory form of luciferase reporter genes, and followed by transfecting the plasmid to oral cancer cell line Ca9-22. We selected stable lines with the reporter plasmid insertion in chromosome and evaluate the efficacy of the cell platform by Bracteanolide A, a natural compound that we have previously identified as a strong antioxidant, which could prevent cell from oxidative stress and strongly drive Nrf2 and downstream target genes. We have successfully constructed this cell platform and confirm its stability and sensitivity. In the future, it could be a good tool toward screening food factors with potential antioxidant acitivities.口試委員會審定書………………………………………………………………………i
謝誌……………………………………………………………………………………...ii
中文摘要 iv
Abstract v
目錄 vi
表目錄 xi
圖目錄 xii
第一章 文獻回顧 1
第一節 氧化壓力傷害與疾病 1
(一)、內生性氧化壓力 2
(二)、外生性氧化壓力 2
(三)、氧化壓力與發炎反應 3
(四)、氧化壓力、疾病與癌症 4
第二節 氧化反應與自由基特性 5
(一)、自由基與活性分子 5
1. 超氧陰離子自由基 (Superoxide anion, O2‧−) 6
2. 過氧化氫 (Hydrogen peroxide, H2O2) 6
3. 羥基自由基 (Hydroxyl radical, ‧OH) 7
4. 單態氧 (Singlet oxygen, 1O2) 7
(二)、自由基與氧化傷害 8
1. 脂質之氧化傷害 8
2. 蛋白質之氧化傷害 9
3. 核酸之氧化傷害 10
(三)、自由基訊息傳遞 10
第三節 抗氧化反應機制 14
(一)、抗氧化物作用原理與機制 14
1. 自由基終止劑 (Free radical terminator) 14
2. 還原劑或氧清除劑 (Reductants and oxygen scavengers) 14
3. 金屬螯合劑 (Metal chelator) 15
(二)、抗氧化系統 15
1. 預防性抗氧化劑 (Preventive antioxidants) / 酵素性抗氧化系統 (Enzymatic antioxidant system) 15
2. 清除自由基抗氧化劑 (Radical scavenging antioxidants) / 非酵素性抗氧化系統 (Non-enzymatic antioxidant system) 16
3. 修復/重新製造之抗氧化劑 (Repair/De novo antioxidants) 17
(三)、抗氧化反應元素(Antioxidant responsive element, ARE) 19
(四)、NF-E2相關因子二 (Nuclear factor-erythroid 2-related factor-2) 及活化機制 20
(五)、NF-E2相關因子二之癌症預防作用 22
第四節 現有抗氧化活性測定方法 23
(一)、抗氧化體外 (In vitro) 試管實驗 23
(二)、抗氧化體內 (In vivo) 實驗 25
第五節 報導基因方法學 28
(一)、螢火蟲冷光酶 (Firefly luciferase, luc) 28
(二)、珊瑚蟲冷光酶 (Renilla luciferase, Rluc) 29
(三)、刺蝦冷光酶 (Nano-Glo luciferase, Nluc) 29
第二章 研究目的與實驗架構 31
第一節 研究目的 31
第二節 實驗架構 32
第三章 材料與方法 33
第一節 實驗試劑與設備 33
第二節 實驗方法 36
(一)、質體製備 36
(二)、質體構築 42
(三)、細胞培養 43
(四)、Secretory Nano-Glo luciferase assay 46
(五)、即時半定量mRNA表現 (Real-time semi-quantification PCR) 48
第三節 統計分析方法 50
第四章 實驗結果 51
第一節 建構即時偵測抗氧化質體 51
1.建構pGL4.18 ARE9-pNL1.3-Nano-Glo luciferase質體 51
2.以限制酶分別處理pGL4.18-ARE9與pNL1.3-Nano-Glo luciferase質體 52
3.以接合酶將pGL4.18-ARE9與pNL1.3-Nano-Glo luciferase質體片斷黏合 54
4. 以限制酶剪切方式確認總質體大小 55
5. 以廠商定序和NCBI BLAST再次確認質體正確性 56
第二節 建立可篩選抗氧化能力食材之細胞平台 58
1. Ca9-22細胞轉殖效率測試 58
2.Neomycin抗生素對於Ca9-22細胞毒殺性測試 62
3.不同劑量t-BHQ誘導抗氧化途徑反應分析 64
4.成功挑選於誘導抗氧化路徑可表現報導質體發冷光的細胞殖株 66
5.於誘導抗氧化途徑下，Ca9-22 clone細胞抗氧化相關基因mRNA表現量 68
6.以細胞免疫螢光染色法確認Ca9-22 clone細胞Nrf2抗氧化路徑可被誘導活化並轉運入細胞核 69
第三節 建立即時偵測抗氧化能力食材細胞平台之測定方式 72
1.負控制組之背景值測定 72
2.抗氧化路徑誘導下，比較報導基因冷光反應與抗氧化相關基因表現量於不同時間點被啟動的情形 73
3.建立全盤掃描式偵測方法 75
4.建立測定標準步驟與校正方法 76
第四節 即時偵測抗氧化能力之細胞平台穩定性測定 77
1.Ca9-22 clone細胞不同代數之穩定度 77
2.Ca9-22 clone細胞反覆冷凍-解凍特性 79
第五節 藉由即時偵測抗氧化能力之細胞平台篩選具抗氧化潛力食材因子 81
第五章 討論 83
第六章 結論 86
第七章 參考文獻 8
Biodiesel Synthesis and Glycerol Transesterification by Layered Double Hydroxides in Stirring Packed-Bed Reactor
No full text石化能源帶給人們方便，卻也讓人類面臨全球暖化等危機，因此許多人投入研究綠色或是永續能源，生質柴油便是其中重要的一角。生質柴油性質與傳統石化柴油相近，又能和石化柴油混合使用，亦具有無毒、生物可分解性、成分中不含硫化物和芳香族類等優點，因此為目前為重要的替代能源之一。 本研究利用層狀複金屬氫氧化物(Layered Double Hydroxides, LDHs)家族中的Mg-Al LDH作為鹼觸媒，以甲醇和大豆油進行轉酯化反應合成生質柴油，並將生質柴油的副產物甘油轉酯化成更具經濟價值的丙三醇1,2-碳酸酯。本研究探討了Mg/Al比例、鍛燒溫度、反應溫度、觸媒使用量以及碳酸二甲酯/甘油之莫耳比值等因素對於反應性之影響，並將LDH合成於α-Al2O3小球上，填充於攪拌填充床連續式反應系統進行反應。 本研究先將Mg-Al LDH進行鍛燒，再利用去碳酸根水─甘油混合液進行層狀結構之重構，並同時於觸媒表面包覆一層甘油防止觸媒因接觸空氣失活。在大豆油之轉酯化反應中，反應溫度60oC、甲醇/大豆油莫耳比為30:1，Mg/Al=5之觸媒使用量為10wt%時，四小時內可達65.72%，升高溫度至100oC，三小時可達87.45%。在甘油轉酯化反應中，在反應溫度95oC下，碳酸二甲酯/甘油莫耳比值為16，並使用二甲基亞碸作為溶劑， Mg/Al=5之顆粒觸媒用量為總反應系統總重之10wt%時，可於7.5小時內達到93.4%的產率。在四角觸媒柱連續式攪拌反應中，當反應溫度為90oC，碳酸二甲酯/甘油為16，使用Mg/Al=5之顆粒觸媒，用量為反應物總重的約10wt%，在滯留時間22.5小時，可於11小時達到穩態，產率80.17%。Fossil fuel brings mankind lots of convenience and boosts the technology development. However, fossil fuel also brings crisis such as global warming and energy shortage. To deal with the problems, many scientists devote themselves into finding green and sustainable energies, and biodiesel is one of them. Biodiesel can be mixed with petro-diesel at any ratio and used in a diesel engine. Biodiesel contains no sulfur and no aromatic compounds. The surge of interest in biodiesel has also highlighted the reduction of greenhouse gas emission and pollution as well as nontoxic and biodegradable. In this research, we transesterificated (1) triglycerides to synthesize biodiesel and; (2) its byproduct glycerol to form a more valuable chemical, glycerol 1,2-carbonate, using layered double hydroxides (LDHs), specifically Mg-Al LDH. We studied the different Mg/Al ratios in catalyst preparation, calcination temperatures of LDH, reaction temperatures, catalyst loadings and the molar ratios of dimethyl carbonate/glycerol, etc., which are critical factors in both transesterification reactions. We had Mg-Al LDH coated on the 3mm spherical α-Al2O3 catalyst in the stirring packed-bed reactor. Mg-Al LDH was first calcined and then rehydrated with decarbonated water-glycerol solution to reconstruct the layer structure and also to protect the catalyst deactivation by air at the same time. In biodiesel synthesis, the yield reached 65.72% in 4 hours under 60oC, 87.45% in 3 hours under 100oC, when the methanol/soybean oil molar ratio was set to be 30, and 10wt% Mg/Al=5 LDH was used in the reaction. The glycerol transesterification was carried out by dimethyl carbonate/glycerol molar ratio 16 with the existence of solvent, dimethyl sulfoxide, using 10wt% Mg/Al=5 LDH on spherical α-Al2O3 at 95oC. The yield of glycerol 1,2-carbonate could reach up to 93.4% within 7.5 hours. When applying 10wt% catalyst of Mg/Al=5 LDH on spherical α-Al2O3 into the stirring packed-bed reactor, the yield of glycerol 1,2-carbonate reached to 80.17% within 11 hours under the residence time 22.5 hours, and dimethyl carbonate/glycerol molar ratio = 16 at 90oC
Experimental Study on Wave Propulsion by an Oscillating Bow Fin
No full text隨著燃油價格的高漲以及全球氣候變遷意識日漸增強，節能減碳早已成為國際關注之議題，並積極尋求如何提升能源使用效率，或再生能源利用以及各種節能的方法，而航運造船領域也不例外。所謂”師法自然”，如何從歷經演化競爭存活下來的生物獲得科技創新研發的啟發也成為一門”仿生學”的學問。在船舶海洋領域，科學及工程專家著眼於海洋迴游魚類如何以低耗能、高效率方式在海裡推進，長程迴游，希望透過了解仿生運動模式達到節能的效果，並將研究成果應用於船舶在實海域的航行，經過多年的研究發展出許多創新設計與裝置，並希望透過發展出的成果達到減少船舶阻力或提升推進效率，且具有節能減碳的效果。此外，也已有一些針對使用被動或主動振動翼來擷取波能以協助船舶推進方法的探索。 本實驗研究的目的即在於尋求可應用於一般商船的節能裝置，應用自航船模的水槽實驗探討在船舶船艏處裝置振動翼，利用船舶於波浪中航行時所引致的船體起伏運動，搭配振動翼主動繞其轉軸縱搖所形成之起伏-縱搖耦合運動，擷取波能直接用以輔助船舶在波浪中推進之可行性驗證，並釐清振動翼主動控制模式。 本實驗研究驗證了應用主動式縱搖振動翼對於輔助船舶於波浪中推進有正面之效果，只要振動翼的縱搖領先起伏相位角在適當範圍內，對於船舶於波浪中推進之速度提升及節能可有顯著的效果。Scientists have found that marine mammals like dolphins and whales swim in high efficiency. Marine mammals may also swim across the ocean by using wave energy and converting it to thrust through proper control of their tail fin. Ships traveling in wave will get ship motions from wave energy. It’s considered to be feasible to find an efficient way to enhance the ship propulsion by extracting wave energy and converting it to useful propulsive thrust. Hence, many concepts of propulsion system using active or passive control of oscillating fin are investigated and applied. However, most of them are focused on small crafts but not on general merchant ships. In the present study, a pair of oscillating bow fin with NACA0016 section controlled actively in pitch are applied to a container ship travelling in head waves for validating its effectiveness. The oscillating fins are placed underneath the front part of the container ship model with bulbous bow. The experiments implement in two wavelength of regular head wave, measure the mean speed of the ship model in wave with controlling the phase angle between heaving and pitching motion of the oscillating bow fin. The target of these experiments is to change the phase angle between heaving and pitching of the oscillating bow fin motion, finding the range of phase angles which enhance the speed of the ship model in wave. These results are compared with the mean speed in wave without flapping the oscillating bow fin. The experimental results show that it’s effective to enhance the speed of the ship model and to save energy in wave propulsion by applying an oscillating bow fin as long as the phase angle between heaving and pitching motion of the fin is in the appropriate range
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
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