1,720,965 research outputs found
EMC implications of implementing WBG devices in battery charger modules for electric vehicles
No full textGaN and SiC semiconductor devices have the potential of drastic downsizing of power converters in applications where size is strictly limited like in electromobility. In electric powertrains, on-board chargers need to operate in a wide voltage and power range limited by the battery and its conditions. In this context, both size and voltage-power range can be achieved through the effective utilization of GaN and SiC devices. Nevertheless, although GaN and SiC devices offer outstanding features in fast transitions, low on-resistances, and the ability to switch faster, these characteristics can generate much higher EM emissions that can affect the charger operation. Consequently, additional circuitry is required to mitigate such emissions although it can jeopardize the ultimate goal of compactness. In this paper, trasients, ringing, harmonic content, and conducted emissions in both GaN and SiC Devices and use of magnetic components is analyzed. Such analysis is conducted with experimental tests under real conditions of battery charging for Electric Vehicles
EMC implications of implementing WBG devices in battery charger modules for electric vehicles
No full textGaN and SiC semiconductor devices have the potential of drastic downsizing of power converters in applications where size is strictly limited like in electromobility. In electric powertrains, on-board chargers need to operate in a wide voltage and power range limited by the battery and its conditions. In this context, both size and voltage-power range can be achieved through the effective utilization of GaN and SiC devices. Nevertheless, although GaN and SiC devices offer outstanding features in fast transitions, low on-resistances, and the ability to switch faster, these characteristics can generate much higher EM emissions that can affect the charger operation. Consequently, additional circuitry is required to mitigate such emissions although it can jeopardize the ultimate goal of compactness. In this paper, trasients, ringing, harmonic content, and conducted emissions in both GaN and SiC Devices and use of magnetic components is analyzed. Such analysis is conducted with experimental tests under real conditions of battery charging for Electric Vehicles
Preparation of ellagic acid concentrate from strawberry pomaces and safety evaluation thereof
No full text草莓粕是在榨草莓汁以釀製草莓酒時產生的副產物，先前已建立由草莓粕中回收鞣花酸 (ellagic acid, EA)的方法。本研究目的為簡化回收鞣花酸濃縮物之流程，並以安氏試驗法(AMES test)及L5178Y TK分析法來評估鞣花酸標準品 (Ellagic acid standard, EAS)，及鞣花酸濃縮物(Ellagic acid concentrate, EAC)的安全性。在溶劑萃取鞣花酸方面，結果發現在甲醇、乙酸乙酯、丙酮和95%乙醇等四種溶劑中，EA萃取回收率以甲醇最佳約67%，其次為丙酮，約53%，再次是95%乙醇，約32%，而乙酸乙酯無法萃出EA。以甲醇及丙酮萃取2次後，再以乙酸乙酯處理萃取物以去除雜質，結果顯示EA幾乎不損失，且EA濃度度由原酸水解後草莓粕原料的0.4%提高至9.6%，乙酸乙酯用量也較原方法減少。在安全性評估方面，安氏試驗結果顯示不論添加S9與否，EAS與EAC對Salmonella typhimurium的五株菌(TA100, TA98, TA102, TA1535和TA97)都沒有顯著的致突變性(p<0.05)。EAS對L5178Y細胞之50%致死率為20 ppm，而EAC在最高濃度(10 ppm)時仍不具任何細胞毒性。EAS及EAC相較於溶劑對照組，突變頻率(mutation frequency)無顯著的差異(p<0.05)。Strawberry pomaces are the byproducts of brewing strawberry wine. In our previous study, a ellagic acid (EA) recovery process from the strawberry pomaces had well been established. The aim of this study, we try to simplify the EA recovery process from strawberry pomaces and evaluate the safety of products, ellagic acid concentrate (EAC), and ellagic acid standard (EAS) by AMES test and L5178Y TK assay. The result of modified processes for recovering ellagic acid was indicated that a more efficient method has been reached by changing the extraction steps according to the properties of solvents. The ellagic acid content of final products (EAC) was 9.6% and ellagic acid was almost fully recovered from raw materials. The results of safety evaluation indicate that neither EAS nor EAC reveal any evidence of mutagenicity sn Salmonella typhimurium five test strains (TA98, TA100, TA102, TA1535 and TA97) either in the presence or absence of S9 activation. EAS showed cytotoxicity at 20 ppm and EAC cause no cytotoxicity at highest concentration (10 ppm). EAS and EAC had no significant mutagenicity compared with negative control of DMSO solvent (p<0.05).目次………………………………….…………………………………………………..1
圖次……………………………………………………………………………………...3
表次……………………………………………………………………………………...4
中文摘要………………………………………………………………………………...5
英文摘要Abstract……………………………………………………………………….6
第一章、 研究動機…………………………………………………………………….7
第二章、 文獻整理…………………………………………………………………….9
壹、 自然界中的鞣花酸…………………………………………………………...9
貳、 鞣花酸之基本性質………………………………………………………….11
參、 鞣花酸之製備……………………………………………………………….16
肆、 鞣花酸之生理活性………………………………………………………….18
I. 抗氧化與抗癌活性…………………………………………………….18
II. 抗致突變性及抗腫瘤發生….…………………………………………20
III. 鞣花酸之美白功效…………………………………………………….21
IV. 鞣花酸之其他生理活性…………………………………………….....22
伍、 鞣花酸之生物可利用率及生物體內之代謝……………………………….23
陸、 鞣花酸之安全性…………………………………………………………….24
柒、 安全性評估方法…………………………………………………………….25
捌、 安氏試驗法 AMES test……………………………………………………..26
玖、 L5178Y TK分析法……………………………………………………….....28
第三章、 材料方法與結果...........................................................................................30
第一部份：鞣花酸濃縮物製程之改進.................................................................30
壹、 實驗架構…………………………………………………………………….30
貳、 實驗材料與器材…………………………………………………………….31
參、 實驗步驟…………………………………………………………………….32
肆、 實驗結果與討論…………………………………………………………….35
第二部份：鞣花酸標準品(EAS)與鞣花酸濃縮物(EAC)之安全性評估.............45
壹、 實驗架構………………………………………………………………….....45
貳、 安氏試驗法.....................................................................................................46
I. 實驗材料與器材….……………………………………………………46
II. 實驗步驟……………………………………………………………….52
III. 實驗結果與討論……………………………………………………….55
參、 L5178Y TK分析法.........................................................................................60
I. 實驗材料與器材……………………………………………………….60
II. 實驗步驟……………………………………………………………….61
III. 實驗結果與討論…….…………………………………………………65
第四章、 結論...............................................................................................................70
第五章、 參考文獻.......................................................................................................7
High Speed Rail Ridership Forecast Study-Model Rebuilt and Analysis
No full text高速鐵路具備高速度、高運能及低污染等優點，是相當具有吸引力之城際運具。自2007年台灣高鐵通車以來，即大幅縮短台灣西部走廊各大城市間的旅行時間，成就「一日生活圈」之概念。由於建設高速鐵路需要相當龐大的投資成本，若由政府主持興建，受到行政程序繁複即財政負擔的影響，將可能使通車時程不斷延宕。近年許多國家將大型公共建設轉向私有化的替代方案。台灣高鐵是世界上最大的BOT建設案，但自通車以來，營運即受到運量不足的影響，造成龐大的財務赤字。於2009年因財務困難，迫使政府不得不提供資金援助。1990年代，交通部高鐵籌備處所委託幾家顧問公司預測高鐵的運量，但大多報告皆樂觀預估運量及營收，是造成後續財務規劃不佳的成因之一。然而由於實際通車日期與當初預測時程不同，許多社會經濟條件已不可同日而語，在20年後的今日與當初所預期之條件大多不符，如GDP、人口、基本費率及行車時間皆不同。此外，台灣社會經濟環境和人文地理因素與其他國家有很大的不同，委託之顧問公司多以他們的經驗來推測需求量，但未必適用於台灣。本研究欲根據台灣高鐵的經驗，重新建構高速鐵路運量預測模式。
該模式分為兩個部分，一為直接總體需求模式，另一為總體羅吉特模式（運具分配模式）。利用歷史巨觀資料校估模式參數，並以台灣高鐵通車後之實際數據驗證模式參數。與實際運量相比，本研究所提出之高鐵運量模式預測誤差約為15%。以次模式預測20年內的高鐵運量及營收值，結果顯示，即將營運通車的高鐵新增三站(苗栗、彰化及雲林)，在民國110年的預測情境下，可增加16％運量量及11％的營收，即對營運有正面幫助。但這三站所貢獻的運量及營收將比現有高鐵嘉義站更低。在高鐵票價策略方面，本研究結果顯示現今台灣高鐵所制定之票價可幾乎創造最大之營收，因此目前票價措施算是合適。在高鐵接駁時間方面，當接駁時間越少，可有效吸引短途旅客(尤其是通勤旅客)，若高鐵站與目前傳統鐵路車站共構，可減少大量的接駁時間，民國110年計算結果顯示會約有55％的運量提升及30％的營收增加。With its virtues of high speed, large capacity, reduced levels of energy consumption, and pollution, high-speed rail (HSR) is emerging as an attractive transportation system. Due to the large investment burden required for HSR projects and the inefficiency of government-sponsored public construction projects, many countries are now turning to the alternative of privatizing their HSR projects. However, the private company often encounters financial deficit when the operating revenue cannot balance the cost. Taiwan high speed rail (THSR) is the largest BOT (Build-Operate-Transfer) case in the world. It once declared bankrupt because of financial difficulties until the government provided funding support in 2009. Some criticisms focused on the overestimated ridership forecasts made by several consultants and institutes. However, the actual operation period is different from the planned one, which involves the changes of socioeconomic, environmental, and geographic backgrounds (such as GDP, population, and fare price). Also, the employed demand forecast models may be characterized by the experiences in other countries, which can be inapplicable in Taiwan. Hence, this study seeks to rebuild HSR ridership forecast model based on the experiences of THSR and re-examine it using actual operation data.
This model is composed of two parts, direct demand forecast model (overall inter-city travel demand), and aggregate logit model (mode split model). The parameters in both models are calibrated by using historical aggregate data and verified by real ridership data after THSR opening, showing that the prediction error of the proposed models is within 15%. The current fare price of THSR can reach the nearly best revenue, implying appropriate pricing strategies. The prediction of THSR ridership and revenue for the next 20 years are conducted based on the developed models. The results show that the three stations (Miaoli, Changhua, and Yunlin) which are currently under construction may increase 16% ridership and 11% revenue in 2021, highlighting their positive effects on future operation. However, the demand generated from each of these three stations may be lower than the one currently with the lowest demand (Chiayi). If THSR stations were built on the conventional railway stations, access time can be significantly reduced, which may lead to 55% ridership and 30% revenue increase. The reduced access time may also attract more short-distance travelers (commute trips).摘要 I
Abstract II
目錄 IV
表目錄 VIII
圖目錄 IX
第一章 緒論 1
1.1 緒論 1
1.2 研究背景與動機 2
1.3 研究目的 4
1.4 研究範疇與限制 5
1.5 研究方法 5
1.6 研究流程與架構 6
第二章 文獻回顧 7
2.1 高速鐵路歷史簡介 7
2.2 1990年代台灣高速鐵路運量預測報告書 8
2.2.1 法國Sofrerail鐵路工程顧問公司報告書 9
2.2.2 香港MVA弘達交通顧問有限公司報告書 11
2.2.3 台灣高鐵運量預測模式小結 12
2.3 高速/城際鐵路運量預測研究 13
2.4 文獻回顧小結 16
第三章 高速鐵路運量預測模式建構 19
3.1 直接總體需求預測模式 19
3.1.1 應變數及自變數選取 19
3.1.1.1 小客車交通量 22
3.1.1.2 國道客運(巴士)交通量 23
3.1.1.3 傳統鐵路(臺鐵)交通量 23
3.1.1.4 國內航空交通量 23
3.1.1.5 國民生產毛額 23
3.1.1.6 戶籍人口數、實住人口數 23
3.1.1.7 小客車持有量 24
3.1.1.8 就業人口數(二三級就業人口數，商務通勤旅次) 25
3.1.1.9 老年人口數(返鄉旅次) 26
3.1.1.10 國內總體旅遊人次(旅遊旅次) 27
3.1.1.11 旅行成本 27
3.1.1.12 旅行時間 30
3.1.2 分段式迴歸模式 34
3.1.3 直接總體需求模式計算 37
3.1.4 多重共線性 39
3.1.5 山脊型迴歸法 40
3.1.5.1 山脊型迴歸法介紹 41
3.1.5.2 山脊型迴歸法偏差常數之選擇 42
3.1.5.3 山脊型標準化迴歸係數之變異數 44
3.1.6 衍生交通量 45
3.2 運具分配模式 50
3.2.1 個體行為運具分配模式 51
3.2.1.1 個體選擇行為模式 51
3.2.1.2 可衡量之效用 52
3.2.1.3 不可衡量之效用 52
3.2.1.4 二項個體行為運具分配模式 53
3.2.1.5 多項羅吉特模式 54
3.2.1.6 巢式羅吉特模式 55
3.2.2 總體運具分配模式 57
3.2.2.1 總體羅吉特模式型態 57
3.2.2.2 總體羅吉特模式之參數校估 58
3.2.3 臺灣總體運具分配模式 59
3.2.3.1 效用函數 59
3.2.3.2 多項羅吉特模式與巢式多項羅吉特模式的選用 60
3.2.4 運具分配模式計算 64
第四章 案例分析 68
4.1 台灣高速鐵路系統案例分析 68
4.1.1 分析範疇與假設 69
4.1.1.1 台灣高鐵既有車站 69
4.1.1.2 台灣高鐵新增車站 71
4.1.1.3 研究預測假設 72
4.1.2 台灣高速鐵路相關資料說明 74
4.2 台灣高速鐵路運量預測結果(包含新增三站) 76
4.3 敏感度分析 80
4.3.1 高速鐵路運具特性敏感度分析 80
4.3.1.1 高速鐵路接駁時間及旅行時間 80
4.3.1.2 高速鐵路旅行成本(票價) 82
4.3.2 小客車運具特性敏感度分析及油價情境分析 84
4.3.2.1 小客車旅行時間 84
4.3.2.2 高速公路收費(ETC)基本費率 84
4.3.2.3 小客車平均乘載人數 85
4.3.2.4 油價(原油價格)情境分析 86
4.3.3 國道客運運具特性敏感度分析 88
4.3.3.1 國道客運旅行時間 88
4.3.3.2 國道客運旅行成本(票價) 89
4.3.4 傳統鐵路運具特性敏感度分析 89
4.3.4.1 傳統鐵路旅行時間 89
4.3.4.2 傳統鐵路旅行成本(票價) 91
4.4 案例分析小結 91
第五章 結論與建議 93
5.1 結論 93
5.2 建議 95
參考文獻 9
Real-time multi-layer translucent material editing
No full text我們在這篇論文中要提出一套系統，他可以讓我們在固定的光源環境下，對多層次半透明物體作材質編輯。這套系統允許使用者改變一些參數，像是散射係數與吸收係數，然後可以即時地看到改變後的樣子，並且包含多次散射與單次散射。我們使用PRT技術來事先計算每個頂點上的轉移函數，然後再藉著係數與轉移函數的內積，來計算每個頂點的顏色。我們利用GPU的性能來加速，以達到即時的繪製效果。This paper present a system to do real-time multi-layer translucent material editing under static lighting with multiple scattering and single scattering. This system allow user to change parameters of BSSRDF function like , and have real-time rendering feedback. We use PRT(precomputed radiance transfer) technique to precompute the transport function of each vertex and compute color of each vertex by dot product of coefficients and transport functions. We use GPU to achieve real-time rendering performance.中文摘要ibstract ii Introduction 1 Related Work 3 Overview 5.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 multi-layer translucent material . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Algorithms 10.1 profile combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 precomputation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Implementation 16.1 Precomputation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.2 Rendering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Result 18.1 comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.2 conclusion and future work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19ibliography 2
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
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