Browsing by Issue Date, starting with "2008-02-25"

Now showing 1 - 20 of 56187

Interfacial reactions of Pt-based Schottky contacts on nGaP
(2008-02-25)
Chu, L. H.
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Chang, E. Y.
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Wu, Y. H.
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Huang, J. C.
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Chen, Q. Y.
We have investigated the interfacial reaction between platinum and InGaP in a Schottky diode structure. There was a 7.5-nm-thick amorphous layer formed at the interface between Pt and InGaP after metal deposition. After annealing at 325 degrees C for 1 min, this amorphous layer increased to 12.8 nm and the reverse leakage current also decreased. The diffusion of Pt atoms and the crystallization of amorphous layer took place after annealing at 325 degrees C for 10 min. Prolonging the annealing to 3 h led to formation of Ga(2)Pt and GaPt(3) phases in InGaP and Schottky diodes degraded after these new phases were observed. (C) 2008 American Institute of Physics.
Investigation of Pr(3+) as a sensitizer in quantum-cutting fluoride phosphors
(2008-02-25)
Lee, Te-Ju
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Luo, Li-Yang
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Cheng, Bing-Ming
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Diau, Wei-Guang
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Chen, Teng-Ming
A quantum-cutting (QC) phosphor K(2)GdF(5):Eu(3+) shows poor optical absorption and a theoretical quantum efficiency (QE) of 107% in the ultraviolet (UV) and vacuum ultraviolet (VUV) excitation spectral ranges. Pr(3+) was codoped as a sensitizer in K(2)GdF(5): Eu(3+) thus increasing the absorption in the UV and VUV spectral regions; the theoretical QE of K(2)GdF(5): Eu(3+), Pr(3+) was increased to 138%. The spectra indicate that the possible mechanisms of QC and energy transfer differ from those of phosphors containing the Gd(3+) -Eu(3+) couple. Temporally resolved measurements of fluorescence decay confirm the proposed QC mechanism for the phosphor containing the Gd(3+) -Eu(3+),Pr(3+) system. (C) 2008 American Institute of Physics.
Terahertz scanning imaging with a subwavelength plastic fiber
(2008-02-25)
Lu, Ja-Yu
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Chiu, Chui-Min
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Kuo, Chung-Chiu
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Lai, Chih-Hsien
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Chang, Hung-Chung
The feasibility to perform terahertz imaging utilizing a terahertz subwavelength plastic fiber is investigated. Dour study shows that, With a low (<1%) fractional power inside the fiber score, the bending loss of the terahertz subwavelength fiber is acceptable to enable large area scanning without seriously sacrificing the signal-to-noise ratio of the acquired image. With a transmission geometry, this feasibility is demonstrated by direct two-dimensional scanning of the terahertz subwavelength fiber output end to image different biological samples and concealed substances. (C) 2008 American Institute of Physics.
Lnfrared photocurrent response of charge-transfer exciton in polymer bulk heterojunction
(2008-02-25)
Yang, Chia-Ming
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Tsai, Pei-Yu
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Horng, Sheng-Fu
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Lee, Kuan-Chen
;
Tzeng, Shin-Rong
We study the charge-transfer exciton absorption and photocurrent response in solution-processed bulk heterojunction based on poly(3-hexylthiophene) donor and (6,6)-phenyl-C(61)-butyric acid methyl ester acceptor in the near-infrared wavelength region. While the exciton absorption exists only for wavelength below 650 nm, direct generation of charge-transfer exciton formed between the donor and acceptor extends the absorption wavelength to 950 nm. For films with micrometer thickness, the photon-to-electron conversion efficiency is about 60% at 750 nm wavelength under reverse voltage bias and the photocurrent to dark current ratio is about 8.6 at 900 nm and remains 3.6 even at 1000 nm. Photodetector with high sensitivity covering exclusively the 650-1000 nm near infrared region can therefore be made without a low bandgap material. The charge-transfer exciton absorption coefficient and photocurrent sensitivity depend on the annealing condition which controls the donor-acceptor morphology. (c) 2008 American Institute of Physics.
A computer method based on simulated annealing to identify aquifer parameters using pumping-test data
(2008-02-25)
Huang, Yen-Chen
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Yeh, Hund-Der
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Lin, Yu-Chung
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環境工程研究所
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Institute of Environmental Engineering
Conventional graphical or computer methods for identifying aquifer parameters have their own inevitable limitations. This paper proposes a computer method based on a drawdown model and a heuristic approach of simulated annealing (SA) to determine the best-fit aquifer parameters of the confined and unconfined aquifer systems. The drawdown model for the confined aquifer is the Theis solution and the unconfined aquifer is the Neuman solution. The estimated results of proposed method have better accuracy than those of the graphical methods and agree well with those of the computer methods based on the extended Kalman filter and Newton's method. Finally, the sensitivity analyses for the control parameters of SA indicate that the proposed method is very robust and stable in parameter identification procedures. Copyright (c) 2007 John Wiley & Sons, Ltd.
Self-assembly through competitive interactions of miscible diblock copolymer/homopolymer blends: Poly(vinylphenol-b-methyl methacrylate)/poly(vinylpyrrolidone) blend
(2008-02-26)
Chen, Wan-Chun
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Kuo, Shiao-Wei
;
Jeng, U-Ser
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Chang, Feng-Chih
;
應用化學系
We have investigated a new type A-b-B/C blend system, poly(vinylphenol-b-methyl methacrylate)/ poly(vinylpyrrolidone) (PVPh-b-PMMA)/PVP, where PVPh-b-PMMA block (A-b-B) copolymer, PVPh/PVP (A/C), and PMMA/PVP (B/C) blends are all miscible through hydrogen bond interaction or dipole-dipole, interaction. Because of the significantly stronger hydrogen bond interaction between PVPh and PVP than that between PVPh and PMMA, this miscible PVPh-b-PMMA copolymer becomes immiscible up on blending with 20-60 wt % PVP (27-56 wt % PMMA in the blend system) and can self-assemble to form ordered morphologies. Results from small-angle X-ray scattering (SAXS) and TEM consistently indicate that different compositions of PVPh-b-PMMA/PVP blends induce different microphase separation structures such as hexagonal and lamellar phases. However, sharp and multiple orders of diffraction are absent from the SAXS profiles, indicating relatively. limited sizes of the ordered domains. Large polydispersity in the molecular weight of PVP and small differences in the interaction parameters of the three components of PVPh, PMMA, and PVP are attributed to be the main reasons that limit the microphase separation in this blend system.
Variation of helical twisting power in self-assembled sugar-appended Schiff base chiral rod-coil amphiphiles
(2008-02-26)
Lin, Tz-Feng
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Ho, Rong-Ming
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Sung, Chien-Hung
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Hsu, Chain-Shu
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應用化學系
A series of sugar-appended Schiff base chiral rod-coil amphiphiles with various alkoxy chain lengths have been synthesized in order to elucidate the variation of the helical twisting power (HTP), that is, the inverse of the pitch length, of the helical texture in the self-assembly of the amphiphiles. The HTP induced by chiral sugar in the self-assembled helical morphology was dependent upon the alkoxy chain length. Increasing the alkoxy chain length caused the self-assembled morphology to change from platelet-like texture to helical-twist morphology with varying pitch length and then revert to the platelet-like texture. This result demonstrates that the HTP reaches a maximum as the alkoxy chain length changes. The transformation from platelet-like to helical-twist morphology is induced by significant steric hindrance, when the effective size of adjacent alkoxy chains reaches the threshold of helical twisting and bending, resulting in the formation of a chiral smectic C phase. However, as the alkoxy chain length increases further, the disordering of the alkoxy chain conformation in the smectic-like layered structure may give rise to a structural imperfection that reduces the steric-hindrance effect. Eventually, the steric-hindrance effect may reach a compromise with the structural imperfection to produce a platelet-like morphology, leading to the formation of a low-order smectic phase.
Efficient red-emitting electrophosphorescent polymers
(2008-02-26)
Yang, Xiao-Hui
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Wu, Fang-Iy
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Neher, Dieter
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Chien, Chen-Han
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Shu, Ching-Fong
We report the synthesis and characterization of a series of electrophosphorescent polymers with a polyfluorene backbone, containing a red-emitting iridium complex and carrier-transporting units as the substitutes of the C-9 position of fluorene. Different specimens and contents of the hole-transporting moieties were found to influence the electroluminescent properties of the polymers. Incorporation of a hole-transporting/electron-blocking interfacial layer and utilization of an efficient electron injection cathode led to the saturated red-emitting electrophosphorescent polymer devices with the peak luminance efficiency and power conversion efficiency of 9.3 cd A(-1) and 10.5 lm W-1, respectively. The efficiencies were 8 cd A(-1)/8 lm W-1 and 5.9 cd A(-1)/4.6 lm W-1, respectively, at 100 and 1000 cd m(-2).
我的服務學習心路：當科學志工遇上志工
(2008-02-26)
郭嘉真
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開放教育推動中心
;
Open Education Office
課程日期： 2008年02月26日(三) 演講人：郭嘉真小姐內容摘要：本主題是國科會科學志工計畫召集人郭嘉真與交大學生分享她開拓國內科學志工的經歷。郭學姐開闢果國的「科學志工」，並與國外科學志工團體接軌。她從無到有，開創新領域、新方向的心路歷程，值得本校學弟妹效法學習。內容：影音實況影音(*.flv檔)
策反疑雲
(2008-02-27)
陳信翰
Electroluminescent polymer structure
(2008-02-28)
Wei, Kung-Hwa
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Chou, Chia-Hung
One type of electroluminescence polymer that include at least one side-chain-tethered polyhedral oligomeric silsesquioxane that will form self-assembled structure and may build a free volume among the polymers to prevent the polymers from stacking and enhance luminescence efficiency and thermal stability.
故宮的青草
(2008-02-28)
管管
Immunohistochemical analysis of a novel dehydroepiandrosterone sulfotransferase-like protein in Drosophila neural circuits
(2008-02-29)
Liu, Tzu-An
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Liu, Ming-Cheh
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Yang, Yuh-Shyong
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生物科技學系
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Department of Biological Science and Technology
Sulfotransferase (ST)-catalyzed sulfation plays an important role in various neuronal functions such as homeostasis of catecholamine neurotransmitters and hormones. Drosophila is a popular model for the study of memory and behavioral manifestations because it is able to mimic the intricate neuroregulation and recognition in humans. However, there has been no evidence indicating that cytosolic ST(s) is(are) present in Drosophila. The aim of this study is to investigate whether or not cytosolic ST(s) is(are) expressed in the Drosophila nervous system. Immunoblot analysis demonstrated the presence of dehydroepiandrosterone (DHEA) ST-like protein in Drosophila brain and a sensitive fluorometric assay revealed its sulfating activity toward DHEA. Immunohistochemical staining demonstrated this DHEA ST-like protein to be abundant in specific neurons as well as in several bundles of nerve fibers in Drosophila. Clarification of a possible link between ST and a neurotransmitter-mediated effect may eventually aid in designing approaches for alleviating neuronal disorders in humans. (C) 2007 Elsevier Inc. All rights reserved.
Surface energy and adhesion energy of solution-based patterning in organic thin film transistors
(2008-02-29)
Zan, Hsiao Wen
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Chou, Cheng-Wei
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Yen, Kuo-Hsi
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光電工程學系
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顯示科技研究所
This study elucidates the patterning of pentacene by adjusting its surface energy. The surface energy was modified by self-assembled monolayer treatment and exposure to ultra-violet (UV) light through a quartz-glass mask. Then, following pentacene deposition, dipping in water was used to remove pentacene from the UV-exposed area. The adhesion energy and the intrusion energy were analyzed to determine the mechanism of this patterning process. The variation of the intrusion energy with the surface energy was found to be the main issue in pentacene patterning. The characteristics of pentacene-organic thin film transistors were also measured to confirm the proposed method. (C) 2007 Elsevier B.V. All rights reserved.
Value systems and decision-making styles of newspaper front-line editors
(2008-03-01)
Sylvie, George
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Huang, J. Sonia
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交大名義發表
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National Chiao Tung University
As American newspapers face declining readership, quality concerns, and changing technology and public tastes, newspaper decision-making style remains relatively unexamined. This study re-examines national survey data on U.S. editors charged with choosing, justifying, editing, and publishing the news. In a search for values that underlie decision-making styles, the study uncovers five style predictors: gender experience, social values, journalistic values, and organizational values. Audience-related values were not significant predictors.
A study of total relative Displacements of permutations in paths and cycles
(2008-03-01)
Cheng, Kai-Chung
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Fu, Hung-Lin
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Chiang, Nam-Po
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Tzeng, Chien-Kuo
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應用數學系
Let G = (V, E) be a connected graph and let phi be a permutation of V. The total relative displacement of the permutation phi in G is delta(phi) (G) = Sigma ({x,y}CV) vertical bar d(x,y) - d(phi(x),phi(y))vertical bar, where d(x, y) means the distance between x and y in G, i.e., the length of a shortest path between x and y. A permutation phi which attains the minimum value of non-zero value of delta(phi)(G) is referred to as a near-automarphism of G and a permutation phi which attains the maximum value of delta(phi)(G) is referred to as a chaotic mapping of G. In this paper, we study the maximum value of delta(phi) (G) among all permutations in paths and cycles.
開膛手傑克的魅惑：道德懲戒、理性規訓與醫療想像
(國立陽明交通大學出版社, 2008-03-01)
陳重仁
本文試圖要回答的問題是：何以發生於西元1888年倫敦東區的開膛手連續殺人命案，到了今天依舊令人感到著迷？何以妓女的身體會成為公開處決與道德管束的對象？何以如此殘暴的公開處決會具有道德懲戒的教化寓含？何以開膛手要是個醫師？開膛手的醫師身分，為何與帝國的維繫以及追求現代化工具理性產生關連？百年來眾多有關開膛手身分與行兇動機的推斷中，皇室涉案論一直是最能增加想像空間並營造恐懼想像的推論，電影《開膛手》正是此推斷最具代表性的電影呈現。本文藉由交叉比對電影文本、解剖醫學史、解剖劇場空間呈現的權力關係，以及西方繪畫藝術與解剖醫學的互文脈絡，檢視西方民眾長久以來對屍體解剖具有的恐懼，並說明何以大體解剖延長施加於身體的刑罰，成為道德制約工具。本文試論受害者身體與醫師形象的想像與重現，是開膛手魅惑歷久彌新的主要原因，並從藝術品呈現、解剖法令制訂以及整建社會觀瞻各方面，探討何以開膛手凶案在文化想像的脈絡中具有執行道德懲戒與建立知識體系的雙重意涵。開膛手的想像營造中刻意挪用時空錯亂的醫療科普觀念，渲染現代醫療所象徵的工具理性。藉由美化開膛手具有專業醫療知識的形象，凸顯醫學象徵紀律與理性的印象，並從中玩弄醫學啟蒙辯證的內在矛盾與衝突：原本應該拿手術刀救人的醫師，在開膛手文學的集體想像中，轉換成為陰森冷酷的道德執行者。
A quaternary germanium(II) phosphate, Na[Ge-4(PO4)(3)]
(2008-03-01)
Lee, Chi-Shen
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Weng, Sheng-Feng
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應用化學系
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應用化學系分子科學碩博班
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Department of Applied Chemistry
A new germanium(II) phosphate, sodium tetragermanium tris( phosphate), Na[Ge-4(PO4)(3)], has been synthesized by a solid-state reaction. The compound is isotypic with [Sn-4(PO4)(3)] (A=Na, K, NH4). It features a [Ge-4(PO4)(3)](-) framework made up of GeO3 pyramids and PO4 tetrahedra, which are linked by shared corners, yielding a three-dimensional structure. The crystal studied showed partial inversion twinning.
Stylized rendering using samples of a painted image
(2008-03-01)
Yan, Chung-Ren
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Chi, Ming-Te
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Lee, Tong-Yee
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Lin, Wen-Chieh
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資訊工程學系
We introduce a novel technique to generate painterly art maps (PAMs) for 3D nonphotorealistic rendering. Our technique can automatically transfer brushstroke textures and color changes to 3D models from samples of a painted image. Therefore, the generation of stylized images or animation in the style of a given artwork can be achieved. This new approach works particularly well for a rich variety of brushstrokes ranging from simple 1D and 2D line-art strokes to very complicated ones with significant variations in stroke characteristics. During the rendering or animation process, the coherence of brushstroke textures and color changes over 3D surfaces can be well maintained. With PAM, we can also easily generate the illusion of flow animation over a 3D surface to convey the shape of a model.
擺脫束縛的都市經驗與文化：珠江三角洲農民工家庭研究
(國立陽明交通大學出版社, 2008-03-01)
葉蔭聰
當代中國由80年代初經濟改革開始，經歷激烈的社會變動，一些學者把這些有目共睹的觀察推進一步，討論在這些變化裡，是否有新的社會連結及政治意涵。一些人把政治熱情與幻想投注在擴張中的私營經濟部門，預言新的政治變動，其他人則對市場經濟所帶來的政治機遇不感樂觀，他們認為，各類新興的社會團體十分政治化，並視之為一種「逃避主義」。本文以幾個珠江三角洲的外來農民工家庭個案為重心，說明及探討這些工人在新的家居領域中的生活經驗；由於大部分工人住進工廠宿舍，而絕大部分工廠宿舍進行男女分隔，所以部分已婚男女民工會在工廠外租房子，與伴侶（已婚或未婚）建立臨時的親密居所，而由此衍生各類社會網絡與活動。本文嘗試超越把家庭視作「自然單元」的觀點，接合上近年研究家居領域的理論，視「家」為一組生活關係、想像空間、領域的集合體，「家」不是簡單地根著於一個地點的物理與社會單位，或一個家庭的容器，它是一處陷於各種張力的地方，包括定居與遷徙，本地實踐與全球力量，是資本主義重新編織權力關係的過程，當中最值得注意的是，弱勢者在日常生活中努力逃避開權力關係。對民工來說，工廠生涯的解放經驗不多，反而是為了一嘗現代生活及獲取經濟回報的自願囚牢，但不少人仍無法透過工廠生涯中找到相對安穩的工人階級生活，工廠的生產關係並沒有帶來工人階級家庭，相反地，農民工再次企圖擺脫自己的工人身分，嘗試從桎梏中逃離出來，創造自己的空間逃逸出政治經濟的羅網，維繫夫妻親密關係，享受同鄉及家庭生活，追求社會身分的上升，用他們自己的方法重新界定都市生活。