Browsing by Issue Date, starting with "2007-07-16"

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Electro-optical properties of poly(1-(difluorophenyl)-2(4-alkylcyclohexyl phenyl)acetylene) organic light-emitting diodes
(2007-07-16)
Huang, Chun-Hao
;
Lee, Chih-Wen
;
Hsu, Chain-Shu
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Renaud, Cedric
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Nguyen, Thien-Phap
For organic light-emitting diodes (OLEDs) applications, we have investigated novel polymers, using substituted polyacetylenes (PA), poly(I (fluorophenyl)-2-(alkylcyclohexylphenyl)acetylene) (PDPA-nF) (n =1 or n = 2) which exhibit air stability, better solubility in common organic solvent and higher luminescence than polyacetylene. In this study, we have used poly[(1-(3,4-difluorophenyl)-2-(4-pentylcyclohexylphenyl) acetylene)] (PDPA-2F) as an emitter in OLEDs and their performance was determined by measuring the cuffent-voltage-luminance characteristic. The devices have a maximum brightness of 827 candela (cd)/M-2 at 12 V and a maximum current efficiency of 0. 7 8 cd/A at 9 V with a maximum luminescence at 536 nm. Influence of the metal electrode on the charge injection was studied using several cathode configurations (Ca, Al and Au) for the devices. Furthermore, the charge injection and transport processes were correlated to the presence of traps inside the polymer, determined by deep level transient spectroscopy (DLTS). (c) 2007 Elsevier B.V. All rights reserved.
在無線通訊系統下適應性RTO的預測方法
(2007-07-16)
羅文嶽
因為舊有的TCP傳輸控制方法直接應用在無線通訊上會產生錯誤,例如一些錯誤的控制數據估測導致誤判為網路壅塞,本發明提出一個為適應性RTO(Retransmission Time Out)控制方法來修正。這個控制方法可以動態改變來回傳輸時間的預測値來適應現在的頻寬狀況。因為正確的RTO數値可以藉由新的適應性的來回傳輸時間的預測値來計算出來,所以可以解決由於因頻寬變動造成不正確的RTO數値所造成誤判網路狀況和不必的重新傳輸問題,從而增加TCP在無線系統下的效能。
表情轉換比對之人臉表情辨識技術
(2007-07-16)
連振昌
;
張揚凱
;
黃仲陵
本發明係提供一種表情轉換比對之人臉表情辨識技術,其係以訓練方式得到各種表情間的特徵轉換矩陣,並可依實際需求調整特徵轉換矩陣的維度大小以控制系統的準確度及運算時間,再以特徵轉換矩陣建立出各種表情模型,將該表情模型應用於臉部表情辨識比對上。在過程中並不需要接觸或穿戴任何裝置,且可有效降低運算量,節省運算時間達到即時辨識之功效。
堆疊式源／汲極與薄通道之複晶矽薄膜電晶體結構，及其製作方法
(2007-07-16)
張國明
;
林俊銘
本發明提供堆疊式源/汲極複晶矽薄膜電晶體結構之製造方法,其簡化了習知製作堆疊式源/汲極複晶矽薄膜電晶體結構之光罩數量且可有效降低汲極附近的高電場並具有降低漏電電流的功效。本發明步驟包括:(1)將非晶矽層再結晶為複晶矽層(02)之步驟;先於基板上沈積一非晶矽層,再進行一般曝光微影以及利用RIE蝕刻技術以定義出具有高區間與低區間之非晶矽島狀物,其中蝕刻後之非晶矽薄通道區剩餘厚度約5-200nm,然後再進行退火以使該非晶矽層再結晶為複晶矽層(02);(2)定義閘極區(05)、源/汲極區(07)與通道區之步驟;(3)佈植步驟;以及(4)接線步驟。
供降低糖尿病患者血糖之複合物
(2007-07-16)
張正
;
林穎男
一種供降低糖尿病患者血糖之複合物,其具有運鐵蛋白與金屬離子(或氧化金屬離子),當運鐵蛋白將金屬離子(或氧化金屬離子)送進細胞時,可促使細胞吸收葡萄糖,並且降低金屬離子(或氧化金屬離子)單獨存在時的生理毒性。另外,本發明之複合物具有降低胰島素抗阻性的作用,可進一步用於治療第二型糖尿病之高血糖及降低胰島素抗阻性。
化合物半導體元件之銅金屬化之歐姆接觸電極
(2007-07-16)
李承士
;
張翼
;
陳克弦
一種化合物半導體元件之銅金屬化之歐姆接觸電極,經過電子束蒸鍍沈積鈀(Pd)層、鍺(Ge)層及銅(Cu)層於化合物半導體元件上所組成,接著利用浮離製程(Lift-off)去除多餘之金屬及光阻,最後進行快速高溫退火過程而形成歐姆接觸電極。其中低電阻値之歐姆接觸電極係利用調整鈀層、鍺層及銅層之厚度及配合退火溫度而形成,可應用於銅金屬化製程,有效增加化合物半導體元件的散熱特性,且使生產成本降低。
以半導體量子點加強螢光效率之高分子發光二極體
(2007-07-16)
韋光華
;
周嘉宏
本發明為提供可製成高分子發光二極體之奈米複材,而奈米複材是導入具表面改質之硫化鎘(量子點)於樹枝狀聚茀發光高分子而形成,並可有效地提升螢光發光效率及電激光效率,製成發光二極體元件後亦能增加元件之穩定性及電性。
Modeling international investment decisions for financial holding companies
(2007-07-16)
Trappey, Charles V.
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Shih, Tsui-Yii
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Trappey, Amy J. C.
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管理科學系
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Department of Management Science
This research analyzes the internationalization process model developed by Johanson and Vahlne and derives two integer programming investment decision models that consider the risk attitudes of investment firms. Johanson and Vahlne's model provides a starting point for building a model that suits the investment approach and decision making process of financial holding companies. In practice, when firms make an international investment decision, there is a need for a model that can generate outputs based on financial measures such as profit, investment returns, and tolerable levels of risk. Thus, in this paper, Johanson and Vahlne's concepts are studied and financial managers are interviewed to derive models that match the investment decision procedures of the firms. The model helps firms manage the risks of their investments and derive accurate investment strategies based on investment objectives and constraints. (c) 2006 Published by Elsevier B.V.
Leaky wave phenomena of a conductor-back dielectric slab covered with a two-dimensionally electromagnetic band gap superstrate
(2007-07-18)
Hwang, R. B.
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電信工程研究所
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Institute of Communications Engineering
[1] This paper presents the leaky wave phenomena associated with a waveguide structure that consists of a conductor-back dielectric slab covered with a superstrate made up of a two-dimensionally ( 2-D) electromagnetic band gap ( EBG) structure. A guided wave has its energy bounced back and forth between the metallic ground plane and the EBG structure that is taken as a frequency-selective reflection mirror. Because of the finite thickness of the 2-D EBG superstrate, the guided wave will leak or radiate some of its energy into the air region above the waveguide structure to become a leaky wave. By the mode-matching method and the transverse resonance technique, the overall waveguide structure is formulated as a rigorous electromagnetic boundary value problem to yield an exact dispersion relation of the waveguide so that the complex propagation constant of a guided mode can be accurately determined, including the phase and attenuation constants. Additionally, the electric field distribution inside the waveguide and the far-field radiation pattern were also calculated to demonstrate the leaky wave phenomena of this waveguide from a microscopic point of view. On the basis of the excitation of leaky waves, the phenomenology concerning a class of directive antennas with EBG structure as superstrate was clarified in this research.
Computational study on the mechanisms and energetics of trimethylindium reactions with H2O and H2S
(2007-07-19)
Raghunath, P.
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Lin, M. C.
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應用化學系分子科學碩博班
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Institute of Molecular science
The reactions of trimethylindium (TMIn) with H2O and H2S are relevant to the chemical vapor deposition of indium oxide and indium sulfide thin films. The mechanisms and energetics of these reactions in the gas phase have been investigated by density functional theory and ab initio calculations using the CCSD(T)/[6-31G(d,p)+Lanl2dz]//B3LYP/[6-31G(d,p)+Lanl2dz] and CCSD(T)/[6-31G(d,p) + Lanl2dz] //MP2/[6-31G(d,p)+Lanl2dz] methods. The results of both methods are in good agreement for the optimized geometries and relative energies. When TMIn reacts with H2O and H2S, initial molecular complexes [(CH3)(3)In:OH2 (R1)] and [(CH3)(3)In:SH2 (R2)] are formed with 12.6 and 3.9 kcal/mol binding energies. Elimination of a CH4 molecule from each complex occurs with a similar energy barrier at TS1 (19.9 kcal/mol) and at TS3 (22.1 kcal/mol), respectively, giving stable intermediates (CH3)(2)InOH and (CH3)(2)InSH. The elimination of the second CH4 molecule from these intermediate products, however, has to overcome very high and much different barriers of 66.1 and 53.2 kcal/mol, respectively. In the case of DMIn with H2O and H2S reactions, formation of both InO and InS is exothermic by 3.1 and 30.8 kcal/mol respectively. On the basis of the predicted heats of formation of R1 and R2 at 0 K and -20.1 and 43.6 kcal/mol, the heats of formation of (CH3)(2)InOH, (CH3)(2)InSH, CH3InO, CH3InS, InO, and InS are estimated to be -20.6, 31.8, and 29.0 and 48.4, 35.5, and 58.5 kcal/mol, respectively. The values for InO and InS are in good agreement with available experimental data. A similar study on the reactions of (CH3)(2)In with H2O and H2S has been carried out; in these reactions CH3InOH and CH3InSH were found to be the key intermediate products.
交大e-News第006期
(2007-07-20)
Secretariat
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國立交通大學秘書室
Correlation of reaction sites during the chlorine extraction by hydrogen atom from Cl/Si(100)-2X1
(2007-07-21)
Hsieh, Ming-Feng
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Chung, Jen-Yang
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Lin, Deng-Sung
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Tsay, Shiow-Fon
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物理研究所
The Cl abstraction by gas-phase H atoms from a Cl-terminated Si(100) surface was investigated by scanning tunneling microscopy (STM), high-resolution core level photoemission spectroscopy, and computer simulation. The core level measurements indicate that some additional reactions occur besides the removal of Cl. The STM images show that the Cl-extracted sites disperse randomly in the initial phase of the reaction, but form small clusters as more Cl is removed, indicating a correlation between Cl-extracted sites. These results suggest that the hot-atom process may occur during the atom-adatom collision. (C) 2007 American Institute of Physics.
Photonic crystal circular-shaped microcavity and its uniform cavity-waveguide coupling property due to presence of whispering gallery mode
(2007-07-23)
Lee, Po-Tsung
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Lu, Tsan-Wen
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Yu, Chia-Ming
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Tseng, Chung-Chuan
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光電工程學系
In this report, we investigate a photonic crystal circular- shaped microcavity ( removing seven air holes) sustaining whispering- gallery mode ( WGM) by shifting the 12 nearest air holes according to the concept of cavity- shaping in micro- disk and micro- gear lasers. The WGM modal characteristics are investigated by three- dimensional ( 3D) finite- difference time- domain ( FDTD) simulations. From well- fabricated devices and simulated results, we obtain and identify WGM single- mode lasing with low threshold and high measured quality factor. By inserting additional waveguides, we also investigate its uniform coupling behaviors in different waveguide- cavity- waveguide geometries in both FDTD simulations and experiments. (c) 2007 Optical Society of America.
Liquid refractometer based on immersion diffractometry
(2007-07-23)
Lu, Sheng-Hua
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Pan, Shan-Peng
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Liu, Tzong-Shi
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Kao, Ching-Fen
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機械工程學系
This study presents a laser diffractometric refractometer for measuring the refractive index of liquids. The refractive index is determined by rotating a reflection grating that is immersed in the fluid under test, and measuring the first- order Littrow diffraction angle. The Littrow angle is easily detected form the interferogram formed by the diffracted beam from the grating and the reflected beam from the liquid surface. No special cell for liquids is required. The alignment and measuring processes are simpler than those of other refractometers. The results of a feasibility experiment reveal that the accuracy of the proposed approach is about 0.003 for a refractive index of around 1.3. (c) 2007 Optical Society of America.
Lasing characteristics of a GaN photonic crystal nanocavity light source
(2007-07-23)
Lai, Chun-Feng
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Yu, Peichen
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Wang, Te-Chung
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Kuo, Hao-Chung
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Lu, Tien-Chang
Lasing characteristics from photonic crystal defects fabricated on bulk GaN are investigated. The device demonstrates multimode lasing with linewidths as narrow as 2-3 angstrom, and an enhanced spontaneous emission factor beta similar to 0.045. The emission spectra indicate that the laser emission is initiated horizontally in the defect nanocavity and then coupled to the vertical radiation, possibly via photonic crystal Bloch modes or by scattering.
Growth inhibitory and apoptosis inducing effect of Perilla frutescens extract on human hepatoma HepG2 cells
(2007-07-25)
Lin, Chih-Sheng
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Kuo, Chao-Lin
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Wang, Jui-Ping
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Cheng, Ju-Sang
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Huang, Zheng-Wen
Perilla frutescens (L.) Britt. (Lamiaceae) has traditionally been used to treat diseases, including tumors, but the antitumorigenesis mechanism is unclear. We evaluated the effects of Perilla frutescens leaf extract (PLE) on proliferation and apoptosis inducing in human hepatoma HepG2 cells using a cell proliferation assay, flow cytometry, and cDNA microarrays. Gene expression and apoptosis were also assessed in HepG2 cells treated with a major constituent of PLE. rosmarinic acid (RosA). In the PLE-treated HepG2 cells, antiproliferative activity (105 mu g/mL) were observed, flow cytometry revealed significant apoptosis, and microarray data indicated that the expression of a lot apoptosis-related genes were regulated in a time-dependent manner. Compared with PLE, RosA (10 mu g/mL; a dose equivalent to 105 mu g/mL of PLE) was less effective in increasing the expression of apoptosis-related genes and apoptosis inducing in HepG2 cells. Thus, additional PLE constituents may influence apoptosis in HepG2 cells. The results of our study suggest that the PLE should be further investigated as a promising to treat hepatocellular carcinoma. (c) 2007 Elsevier Ireland Ltd. All rights reserved.
Ab initio chemical kinetics for the OH plus HNCN reaction
(2007-07-26)
Xu, Shucheng
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Lin, M. C.
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應用化學系分子科學碩博班
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Institute of Molecular science
The kinetics and mechanism of the reaction of the cyanomidyl radical (HNCN) with the hydroxyl radical (OH) have been investigated by ab initio calculations with rate constants prediction. The single and triplet potential energy surfaces of this reaction have been calculated by single-point calculations at the CCSD(T)/6-311+G(3df,2p) level based on geometries optimized at the B3LYP/6-311+G(3df,2p) and CCSD/6-311++ G(d,p) levels. The rate constants for various product channels in the temperature range of 300-3000 K are predicted by variational transition-state and Rice-Ramsperger-Kassel-Marcus (RRKM) theories. The predicted total rate constants can be represented by the expressions k(total) = 2.66 x 10(+2) x T-4.50 exp(-239/T) in which T = 300-1000 K and 1.38 x 10(-20) x T-2.78 exp(1578/T) cm(3) molecule(-1) s(-1) where T = 1000-3000 K. The branching ratios of primary channels are predicted: k(1) for forming singlet HON(H)CN accounts for 0.32-0.28, and k(4) for forming singlet HONCNH accounts for 0.68-0.17 in the temperature range of 300-800 K. k(2) + k(7) for producing H2O + NCN accounts for 0.55-0.99 in the high-temperature range of 800-3000 K. The branching ratios of k(3) for producing HCN + HNO, k(6) for producing H2N + NCO, k(8) for forming (HN)-H-3(OH)CN, k(9) for producing CNOH + (NH)-N-3, and k(5) + k(10) for producing NH2 + NCO are negligible. The rate constants for key individual product channels are provided in a table for different temperature and pressure conditions.
Computational study on the kinetics and mechanisms for the unimolecular decomposition of formic and oxalic Acids
(2007-07-26)
Chang, Jee-Gong
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Chen, Hsin-Tsung
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Xu, Shucheng
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Lin, M. C.
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應用化學系分子科學碩博班
The kinetics and mechanisms for the unimolecular decomposition reactions of formic acid and oxalic acid have been studied computationally by the high-level G2M(CC1) method and microcanonical RRKM theory. There are two reaction pathways in the decomposition of formic acid: The dehydration process starting from the Z conformer is found to be the dominant, whereas the decarboxylation reaction starting from the E conformer is less competitive. The predicted rate constants for the dehydration and decarboxylation reactions are in good agreement with the experimental data. The calculated CO/CO2 ratio, 13.6-13.9 between 1300 and 2000 K, is in close agreement with the ratio of 10 measured experimentally by Hsu et al. (In The 19th International Symposium on Combustion; The Combustion Institute: Pittsburgh, PA, 1983; p 89). For oxalic acid, its isomer with two intramolecular hydrogen bonds is the most stable structure, similar to earlier reports. Two primary decomposition channels of oxalic acid producing CO2 + HOCOH with barriers of 33-36 kcal/mol and CO2 + CO + H2O with a barrier of 39 kcal/mol were found. At high temperatures, the latter process becomes more competitive. The rate constant predicted for the formation of CO2 and HOCOH (the precursor of HCOOH) agrees well with available experimental data. The mechanism for the isomerization of HOCOH to HCOOH is also discussed.
A first-principles analysis for sulfur tolerance of CeO2 in solid oxide fuel cells
(2007-07-26)
Chen, Hsin-Tsung
;
Choi, YongMan
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Liu, Meilin
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Lin, M. C.
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應用化學系分子科學碩博班
The mechanism for H2S-CeO2(111) interactions in solid oxide fuel cells (SOFCs) has been investigated by using periodic density functional theory (DFT) calculations. In order to properly characterize the effect of the localization of Ce-4f states on the interactions, DFT + U calculations were applied. Adsorption of H2S, SH, and atomic S was initially examined to locate energetically favorable intermediates. The species adsorb favorably at the Ce-top, O-top, and Ce-O bridging sites, respectively. Potential energy profiles for the H2S-CeO2 (111) interactions along the three product channels producing H-2, H2O, and SO2 were constructed using the nudged elastic band (NEB) method. Calculations show that H2S weakly bounds on CeO2(111) with a small binding energy, followed by dehydrogenation processes, forming surface sulfur species with an exothermicity of 29.9 kcal/mol. Molecular-level calculations demonstrated that the SO2-forming pathway is energetically most favorable.
Computational study of reaction pathways for the formation of indium nitride from trimethylindium with HN3: Comparison of the reaction with NH3 and that on TiO2 rutile (110) Surface
(2007-07-26)
Tzeng, Yi-Ren
;
Raghunath, P.
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Chen, Szu-Chen
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Lin, C.
;
應用化學系分子科學碩博班
The reactions of trimethylindium (TMIn) with HN3 and NH3 are relevant to the chemical vapor deposition of indium nitride thin film. The mechanisms and energetics of these reactions in the gas phase have been investigated by density functional theory and ab initio calculations using the CCSD(T)/Lanl2dz//B3LYP/Lanl2dz and CCSD(T)/Lanl2dz//MP2/Lanl2dz methods. The results of both methods are in good agreement for the optimized geometries and relative energies. These results suggest that the reaction with HN3 forms a new stable product, dimethylindiumnitride, CH3-InN-CH3 via another stable In(CH3)(2)N-3 (dimethylindium azide, DMInA) intermediate. DMInA may undergo unimolecular decomposition to form CH3InNCH3 by two main possible pathways: (1) a stepwise decomposition process through N-2 elimination followed by CH3 migration from In to the remaining N atom and (2) a concerted process involving the concurrent CH3 migration and N-2 elimination directly giving N-2 + CH3InNCH3. The reaction of TMIn with NH3 forms a most stable product DMInNH2 following the initial association and CH4-elimination reaction. The required energy barrier for the elimination of the second CH4 molecule from DMInNH2 is 74.2 kcal/mol. Using these reactions, we predict the heats of formation at 0 K for all the products and finally for InN which is 123 +/- 1 kcal/mol predicted by the two methods. The gas-phase reaction of HN3 with TMIn is compared with that occurring on rutile TiO2 (110). The most noticeable difference is the high endothermicity of the gas-phase reaction for InN production (53 kcal/mol) and the contrasting large exothermicity (195 kcal/mol) released by the low-barrier Langmuir-Hinshelwood type processes following the adsorption of TMIn and HN3 on the surface producing a horizontally adsorbed InN(a), Ti-NIn-O(a), and other products, CH4(g) + N-2(g) + 2CH(3)O(a) [J. Phys. Chem. B 2006, 110, 2263].