Browsing by Issue Date, starting with "2005-07-22"

Now showing 1 - 20 of 66304

Plate-based biochemical assay using quantum dots as a fluorescent labeling agent
(2005-07-22)
Huang, CP
;
Liu, HW
;
Tsao, CY
;
Yin, LT
;
Chiu, SF
A biochemical assay based on fluorescence imaging analysis by confocal laser scanning as a detection technique is specified. The method involved a glass plate coated with nitrocellulose (NC), where alpha-human-IgE-biotin at various concentrations was immobilized on an NC plate. Luminescent core-shell CdSe/ZnS QD-SA conjugates were then used as a fluorescent labeling agent to be captured specifically by biotinated alpha-human-IgE immobilized in a micro-array by affinity binding between SA and biotin in a plate-based biochemical assay. A confocal laser scanner was used to detect the fluorescence signals from the alpha-human-IgE-biotin-SA-QD complex. Experimental findings reveal that fluorescence intensity of QD-SA saturated at QD concentrations above 0.4 mg/ml. Moreover, a calibration curve between the fluorescence intensity and the concentration of alpha-human-IgE-biotin is plotted. The range of detectable concentrations of biotinlated alpha-human IgE was found to be between 3.3 and 100 mu g/ml in the a-human-IgE-biotin-SA-QD complex. Therefore, the results were consistent with the binding specificity in a plate-based biochemical assay, as determined using luminescent QDs as a labeling agent. (c) 2004 Elsevier B.V. All rights reserved.
Plate-based biochemical assay using quantum dots as a fluorescent labeling agent
(2005-07-22)
Huang, CP
;
Liu, HW
;
Tsao, CY
;
Yin, LT
;
Chiu, SF
A biochemical assay based on fluorescence imaging analysis by confocal laser scanning as a detection technique is specified. The method involved a glass plate coated with nitrocellulose (NC), where alpha-human-IgE-biotin at various concentrations was immobilized on an NC plate. Luminescent core-shell CdSe/ZnS QD-SA conjugates were then used as a fluorescent labeling agent to be captured specifically by biotinated alpha-human-IgE immobilized in a micro-array by affinity binding between SA and biotin in a plate-based biochemical assay. A confocal laser scanner was used to detect the fluorescence signals from the alpha-human-IgE-biotin-SA-QD complex. Experimental findings reveal that fluorescence intensity of QD-SA saturated at QD concentrations above 0.4 mg/ml. Moreover, a calibration curve between the fluorescence intensity and the concentration of alpha-human-IgE-biotin is plotted. The range of detectable concentrations of biotinlated alpha-human IgE was found to be between 3.3 and 100 mu g/ml in the a-human-IgE-biotin-SA-QD complex. Therefore, the results were consistent with the binding specificity in a plate-based biochemical assay, as determined using luminescent QDs as a labeling agent. (c) 2004 Elsevier B.V. All rights reserved.
Sequence distribution and polydispersity index affect the hydrogen-bonding strength of poly(vinylphenol-co-methyl methacrylate) copolymers
(2005-07-26)
Lin, CL
;
Chen, WC
;
Liao, CS
;
Su, YC
;
Huang, CF
A series of poly(vinylphenol-co-methyl methacrylate) (PVPh-co-PMMA) block and random copolymers were prepared through anionic and free radical polymerizations, respectively, of 4-tert-butoxystyrene and methyl methacrylate and subsequent selective hydrolysis of the 4-tert-butoxystyrene protective groups. Analysis of infrared spectra suggests that the random copolymer possesses a higher fraction of hydrogen-bonded carbonyl groups and a larger interassociation equilibrium constant relative to those of a block copolymer containing similar vinylphenol content because of the different sequence distribution that may arise from the so-called intramolecular screening effect. In contrast, the glass transition temperature of the block copolymer, which has the lower polydispersity index, is higher than that of the random copolymer at the same composition.
Luminescence and energy transfer of Eu- and Mn-coactivated CaAl2Si2O8 as a potential phosphor for white-light UVLED
(2005-07-26)
Yang, WJ
;
Luo, LY
;
Chen, TM
;
Wang, NS
;
應用化學系
A series of Eu2+- and Mn2+-coactivated CaAl2Si2O8 phosphors have been synthesized at 1400 degrees C under a reduced atmosphere and their luminescence properties have been investigated as a function of activator and coactivator concentrations. We have discovered that energy transfers from Eu2+ to Mn2+ by directly observing significant overlap of the excitation spectrum of Mn2+ and the emission spectrum of Eu2+ as well as the systematic relative decline and growth of emission bands of Eu2+ and Mn2+, respectively. The critical distance and average separation of Eu2+ and Mn2+ have also been calculated. By utilizing the principle of energy transfer, we have also demonstrated that with appropriate tuning of activator content CaAl2Si2O8:Eu2+ Mn2+ phosphors exhibit great potential to act as a phosphor for white-light ultraviolet light-emitting diodes (UVLEDs).
Miscibility behavior and interaction mechanism of polymer electrolytes comprising LiClO4 and MPEG-block-PCL copolymers
(2005-07-26)
Chiu, CY
;
Hsu, WH
;
Yen, YJ
;
Kuo, SW
;
Chang, FC
We have used DSC, FTIR spectroscopy, and ac impedance techniques to investigate in detail the miscibility behavior, interaction mechanism, and ionic conductivity of polymer electrolytes composed of lithium perchlorate (LiClO4) and monomethoxypoly(ethylene glycol)-block-poly(c-caprolactone) (MPEG-PCL) diblock copolymer. The existence of the PCL phase in the MPEG-PCL block copolymer tends to retard the crystallinity of MPEG and results in a higher ionic conductivity for the LiClO4/MPEG-PCL based polymer electrolyte. DSC analyses indicate that the phase separation occurs for some compositions of the LiClO4/MPEG-PCL blends. In addition, FTIR spectroscopy studies reveal the complicated interactions that occur within the LiClO4/MPEG-PCL blend system upon varying the LiClO4 content and increasing the temperature. For the LiClO4/MPEG-PCL blend system, the relative intensity of the "complexed" carbonyl stretching band of the PCL block tends to increase when either the LiClO4 concentration or the length of the PCL block increases. For some compositions of LiClO4/MPEG-PCL, when the temperature is increased from 120 to 180 degrees C, the relative intensity of the "complexed" C=O group increases; this phenomenon is different from that observed for the LiClO4/PCL homopolymer blend.
CdS nanoparticles induce a morphological transformation of poly(styrene-b-4-vinylpyridine) from hexagonally packed cylinders to a lamellar structure
(2005-07-26)
Yeh, SW
;
Wei, KH
;
Sun, YS
;
Jeng, US
;
Liang, KS
Mercaptoacetic acid-modified CdS nanoparticles disperse selectively in the poly(4-vinylpyridine) domains of poly(styrene-b-4-vinylpyridine) (S4VP) block copolymer as a result of the formation of hydrogen bonds. This process in turn induces the morphological transformation of S4VP from a hexagonally packed cylinder structure into a lamellar structure, as evidenced from transmission electron microscopy, atomic force microscopy, and small-angle X-ray scattering studies. This transformation is consistent with that suggested by a theoretical prediction of the phase diagram of the mixed diblock copolymer/nanoparticle system.
Preparation and supramolecular self-assembly of a polypeptide-block-polypseudorotaxane
(2005-07-26)
Lee, HF
;
Sheu, HS
;
Jeng, US
;
Huang, CF
;
Chang, FC
We have successfully prepared a new class of self-assembled biomaterial: a polypeptide-block-polypseudorotaxane diblock copolymer. This diblock copolymer is comprised of an a-helical polypeptide rod, based on gamma-benzyl-L-glutamate, and an originally coiled segment P(EO19-r-PO3); it forms inclusion complexes with a-cyclodextrins (alpha-CDs) to give crystalline polypseudorotaxanes. Formation of the polypseudorotaxane converts the conformation of P(EO19-r-PO3) from a flexible chain into a rodlike structure, which results in a novel block copolymer exhibiting a rod-rod conformation. Intrinsic interactions (e.g., the polypseudorotaxane's channel-type crystallization, the polypeptide's secondary structure, and microphase separation) within and between these rod-rod diblock copolymers contribute to their hierarchical self-assembly behavior, which we characterized using DSC, H-1 NMR spectroscopy, C-13 CP/MAS NMR spectroscopy, WAXS, and SAXS. The data obtained from the WAXS and SAXS studies clearly indicate the formation of juxtaposed bilayer-like nanostructure featuring hexagonally packed PBLG stacks and channel-type polypseudorotaxane moieties.
Highly efficient red-electrophosphorescent devices based on polyfluorene copolymers containing charge-transporting pendant units
(2005-07-28)
Wu, FI
;
Shih, PI
;
Tseng, YH
;
Chen, GY
;
Chien, CH
We have systematically examined the photoluminescence (PL) and electroluminescence (EL) behavior of blends comprising two efficient red phosphors doped, respectively, into the blue-emitting polyfluorene derivatives PF-TPA-OXD and PF-OXD. The host polymers, which contain both hole- and electron-transporting or merely electron-tran sporting side chains, are capable of facilitating charge injection and transport. After determining the HOMO and LUMO energy levels of these materials, we were able to match the dopant with its most suitable host to achieve the direct formation and confinement of an exciton at the dopant. This configuration also leads to a reduction in the electrical excitation of the host polymer, which in turn decreases the degree of exciton loss arising from nonradiative decay of the host triplet. Using this approach, we were able to realize the production of high-performance red-electrophosphorescent devices. For Os(fppz)-doped devices, we obtain a balanced charge recombination in conjunction with higher current and luminance when using PF-TPA-OXD as the host matrix; this device reached a maximum external quantum efficiency of 8.37% with a peak brightness of 16 720 cd/m(2). The absence of charge-transporting pendant units, i.e., the device fabricated from poly [9,9-dioctylfluorene-2,7-diyl] (POF), led, however, to relatively poor electroluminescence characteristics (5.81% and 2144 cd/m(2)).
Incorporating hidden Markov models for identifying protein kinase-specific phosphorylation sites
(2005-07-30)
Huang, HD
;
Lee, TY
;
Tzeng, SW
;
Wu, LC
;
Horng, JT
Protein phosphorylation, which is an important mechanism in posttranslational modification, affects essential cellular processes such as metabolism, cell signaling, differentiation, and membrane transportation. Proteins are phosphorylated by a variety of protein kinases. In this investigation, we develop a novel tool to computationally predict catalytic kinase-specific phosphorylation sites. The known phosphorylation sites from public domain data sources are categorized by their annotated protein kinases. Based on the concepts of profile Hidden Markov Models (HMM), computational models are trained from the kinase-specific groups of phosphorylation sites. After evaluating the trained models, we select the model with highest accuracy in each kinase-specific group and provide a Web-based prediction tool for identifying protein phosphorylation sites. The main contribution here is that we have developed a kinase-specific phosphorylation site prediction tool with both high sensitivity and specificity. (c) 2005 Wiley Periodicals, Inc.
Discovering common structural motifs of ribosomal RNA secondary structures in prokaryotes
(2005-08-01)
Huang, HD
;
Horng, JT
;
Wu, LC
;
Fang, SF
;
生物資訊及系統生物研究所
Certain structural motifs, like tetra-loops, in ribosomal RNA are known to functionally implicate in virtually every aspect of protein synthesis. Ribosomal RNA molecules were also widely used as a tool in molecular evolutionary studies because of their ubiquity, size and low evolutionary rate. In this study, we adapt a data mining approach to discover common structural motifs, and then we use a machine learning approach to identify discriminating CSMs from groups of organisms. Finally, we construct phylogeneitc trees to investigate the evolution of ribosomal RNA by serving the CSMs discovered as targets, which are used to estimate the evolutionary relatedness between organisms. The aim of this study is to discover common structural motifs (CSMs), i.e., those single-strain regions shared in ribosomal RNA secondary structures by several organisms, which are related to specific domains or functions. We discover a set of common structural motifs from several data sets of Archaea and Bacteria. Significant CSMs are then induced by a decision tree. Furthermore, phylogenetic trees are constructed based on CSMs and primary sequences of SSU 16 S ribosomal RNA.
磁光式之近場光學光儲存元件
(2005-08-01)
徐文祥
;
謝漢萍
;
孫翊庭
本發明係提供一種磁光式之近場光學光儲存元件，係先利用犧牲層製作空氣軸承結構；再定義一初始小孔，並以電鍍法縮小該孔至奈米等級，再以兩次之厚膜光阻層配合兩次電鍍製程，製作高深寬比之金屬線圈結構與金屬內連線；可有效利用面積與降低電阻，最後利用微影製程中對不同區域的不同曝光量控制，定義單層光阻形成具有特定尺寸且不同厚度之結構，接著配合回流(reflow)即可利用一連續製程製作出結合超半球固態浸沒式透鏡(solid immersion lens)、奈米微孔、金屬線圈、空氣軸承之磁光(MO)讀取頭，而不需精密昂貴的設備，並可批次大量生產，免去組裝的步驟，並且不用高精密度之儀器即可製作，達到高資料儲存與複寫。
超半球固態浸沒式透鏡之製法
(2005-08-01)
徐文祥
;
孫翊庭
本發明係提供一種超半球固態浸沒式透鏡之製法，係於一基材上塗佈正光阻層後，以第一、二片光罩進行第一、二次曝光，可經由第一次足量曝光在正光阻層上產生之圖案來進行對準，使得第二片光罩上之曝光圖案可經由對準轉移到正光阻層上的特定區域，接著進行回流(reflow)，即可形成超半球固態浸沒式透鏡(SSIL)；可使整個製程容易而不需昂貴或是複雜的設備即可完成，且方便利用後續的半導體製程額外製作其他光學元件；與已製作之超半球固態浸沒式透鏡(SSIL)作整合，所以不需組裝即可製作具有功能性的元件，進而達到易於製作，且應用面廣泛易與其他光學元件作整合，利於批次大量生產。
Optical properties of a novel yellow fluorescent dopant for use in organic LEDs
(2005-08-01)
Choy, WCH
;
Wu, YS
;
Chen, CH
;
Cheah, KW
;
電子與資訊研究中心
In this paper, the optical properties of a novel organic, 2,8-di(t-butyl)-5,11-di[4(t-butyl)phenyl]-6,12-diphenylnaphthacene (tetra(t-butyl)rubrene) have been investigated. Our results show that there are two peaks in the photoluminescence (PL) spectra of tetra(t-butyl) rubrene (TBRb) which are also confirmed in the electroluminescence (EL) spectra. Photo-quenching of the PL intensity is observed when the irradiation time increases. It is shown that oxidation is the dominant reason for photo-quenching. The absolute refractive index and absorption coefficient have also been determined and the results correlate well with the PL results. The results show that TBRb can be a good dopant to achieve the Forster energy transfer and to assist light emission. The optical properties of TBRb are similar to those of rubrene; however, the PL of TBRb is much stronger than that of rubrene. Finally, although crystalline organics have been commonly reported by heating the sample, we report crystallization of TBRb at low temperature < 230 K when the TBRb film is in an amorphous form before cooling.
Recursive EM and SAGE-inspired algorithms with application to DOA estimation
(2005-08-01)
Chung, PJ
;
Bohme, JF
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper is concerned with recursive estimation using augmented data. We study two recursive procedures closely linked with the well-known expectation and maximization (EM) and space alternating generalized EM (SAGE) algorithms. Unlike iterative methods, the recursive EM and SAGE-inspired algorithms give a quick update on estimates given new data. Under mild conditions, estimates generated by these procedures are strongly consistent and asymptotically normally distributed. These mathematical properties are valid for a broad class of problems. When applied to direction of arrival (DOA) estimation, the recursive EM and SAGE-inspired algorithms lead to a very simple and fast implementation of the maximum-likelihood (ML) method. The most complicated computation in each recursion is inversion of the augmented information matrix. Through data augmentation, this matrix is diagonal and easy to invert. More importantly, there is no search in such recursive procedures. Consequently, the computational time is much less than that associated with existing numerical methods for finding ML estimates. This feature greatly increases the potential of the ML approach in real-time processing. Numerical experiments show that both algorithms provide good results with low computational cost.
Enhancing the frequency response of cross-polarization wavelength conversion
(2005-08-01)
Wei, CC
;
Huang, MF
;
Chen, J
;
光電工程學系
;
Department of Photonics
This work presents a novel wavelength conversion scheme, differential cross-polarization modulation (DXPoM), using an extra birefringence delay to enhance the performance of the conventional cross-polarization modulation. Simulation and experimental results confirm that the predicted performance is enhanced. Using the proposed scheme improves rise time by over 300 %, reduces timing jitter by 50 %, and increases extinction ratio by 9 %.
製作自行聚合奈米粒之方法
(2005-08-01)
陳衛國
;
李明知
;
周武清
;
陳文雄
;
柯文政
一種用以成長奈米粒的方法，係可在任何晶格匹配度材料之緩衝層上，不需透過圖案遮罩(mask)之製作，即可自行聚合方式(self-assembled)成長包含III-V族、II- VI族或IV-IV族材料之二元、三元以上化合物之奈米粒為特徵。該方法係在基板上先成長任一種材料之緩衝層，然後於適當溫度範圍內完成週期性流量調制磊晶成長，包含：在通入第二反應物前，先通入清除氣體並調制第一反應物至較低第一莫耳流量範圍，致使通入之第二反應物得以在緩衝層上形成金屬或該高金屬含量化合物島狀物，再通入清除氣體以清除殘餘未形成金屬或高金屬含量化合物島狀物之第二反應物，再調制第一反應物至較高第二莫耳流量範圍使該金屬或該高金屬含量化合物島狀物可以形成奈米粒。最後在完成週期性流量調制磊晶成長後，於較高之成長溫度下進行再結晶化步驟，以形成結構性佳之高品質奈米粒。
Overlay metrological system for overlaid linear gratings by an interferoscatterometer
(2005-08-01)
Shyu, DM
;
Lu, MH
;
光電工程學系
;
Department of Photonics
Interferoscatterometry is an optical measurement technology based on the analysis of light scattered and interfered from a periodic structure. In this work, first we build up a model for this system by the rigorous coupled wave analysis. With the model we calculate the diffractive efficiency of overlaid linear gratings with a mirror located in the incident region. Then, from the analyses of the overlaid linear gratings we obtain the best structure which has the highest sensitivity in the interferoscatterometry. Finally, we measure a sample and get experimental signatures. In order to get the overlay between the upper and lower grating, we compare the experimental signatures with theoretical signatures which are built in a library. The application of the interference technique on the scatterometry shows a higher sensitivity and a longer measurement range. (c) 2005 American Institute of Physics.
橫向絕緣閘雙極性電晶體結構
(2005-08-01)
張隆國
;
蔡銘裕
本發明係提供一種橫向絕緣閘雙極性電晶體結構，係使該電晶體之陽極端與陰極端皆為P^＋／N^＋平行對接節段，但卻為分離且對稱式之結構，若以電子／電洞路徑而言，則為電子／電洞路徑完全分離，如此可大幅提高元件之閂鎖電流，改善元件的安全操作區域。並可使該電晶體結合三維降低表面電場原理，使其陽極端／陰極端亦為P^＋／N^＋平行對接節段，而其漂移區則分別是N^–、P^–的平行帶狀區塊，形成一橫向絕緣閘雙極性電晶體與一逆偏PIN飛輪二極體並聯的結構，若以電子／電洞路徑而言則為電子／電洞路徑部份分離，使元件除了在截止狀態時具有高耐壓特性外，在導通狀態時亦具有閂鎖現象的抗受能力。
申請隨班附讀相關事項說明
(國立陽明大學, 2005-08-01)
陽明電子報編輯小組
＜教學服務組／提供＞本校94學年度第1學期申請隨班附讀相關事項如說明，欲申請之學員，應於94年7月20日至94年9月5日前向本校教學服務組辦理申請手續.....
多媒體製作研習課程
(國立陽明大學, 2005-08-01)
陽明電子報編輯小組
＜資訊與通訊中心／提供＞為配合網路教學平台推廣，資通中心規劃一系列相關多媒體製作課程，以提供老師製作多媒體教材之參考，歡迎有興趣者報名參加.....