Browsing by Issue Date, starting with "2007-02-05"

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Fabrication and low temperature thermoelectric properties of NaxCoO2 (x=0.68 and 0.75) epitaxial films by the reactive solid-phase epitaxy
(2007-02-05)
Chang, W. J.
;
Hsieh, C. C.
;
Chung, T. Y.
;
Hsu, S. Y.
;
Wu, K. H.
The authors have fabricated NaxCoO2 thin films via lateral diffusion of sodium into Co3O4 (111) epitaxial films (reactive solid-phase epitaxy [Ohta , Cryst. Growth Des. 5, 25 (2005)]). The environment of thermal diffusion is key to the control of the sodium content in thin films. From the results of x-ray diffraction and in-plane rho(ab), the epitaxial growth and the sodium contents of these films were identified. The thermoelectric measurements show a large thermoelectric power similar to that observed in single crystals. The quasiparticle scattering rate is found to approach zero at low temperatures, consistent with the small residual resistivity, indicating high quality of the NaxCoO2 thin films. (c) 2007 American Institute of Physics.
Modified buffer layers for polymer photovoltaic devices
(2007-02-05)
Ko, Chu-Jung
;
Lin, Yi-Kai
;
Chen, Fang-Chung
;
Chu, Chi-Wei
;
光電工程學系
The influence of anode buffer layers on the performance of polymer photovoltaic devices based on blends of poly(3-hexylthiophene) and [6,6]-phenyl-C-61-buytyric acid methyl ester has been investigated. The buffer layers consist of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT-PSS) doped with different concentrations of mannitol. Improved power conversion efficiency, up to 5.2%, has been observed by reducing the resistance of PEDOT:PSS after doping. One extrapolation method has been developed to exclude the resistance from the connection of the electrodes from the total device resistance. The results confirm that the device improvement is due to the reduction of series resistance of the PEDOT:PSS after the mannitol doping. (c) 2007 American Institute of Physics.
Downregulation of angiotensin converting enzyme II is associated with pacing-induced sustained atrial fibrillation
(2007-02-06)
Pan, Chun-Hsu
;
Lin, Jiunn-Lee
;
Lai, Ling-Ping
;
Chen, Chien-Lung
;
Huang, Shoei K. Stephen
Atrial fibrillation (AF), the most common cardiac arrhythmia, is frequently accompanied by atrial interstitial fibrosis. Angiotensin II (Ang II) dependent signaling pathways have been implicated in interstitial fibrosis during the development of AF. However, Ang II could be further degraded by angiotensin converting enzyme II (ACE2). We examined expression of ACE2 in the fibrillating atria of pigs and its involvement in fibrotic pathogenesis during AF. Nine adult pigs underwent continuous rapid atrial pacing to induce sustained AF and six pigs were sham controls (i.e., sinus rhythm; SR). In the histological examinations, extensive accumulation of extracellular matrix in the interstitial space of the atria, as evidenced by Masson's trichrome stain, were found in fibrillating atria. The relative amount of collagen type I in the atria with AF was significantly increased as compared with that in the SR. Local ACE activity in the fibrillating atria was also markedly higher than that in the SR subjects. ACE2 gene and protein expression in the AF subjects were significantly decreased compared with those in the SR subjects, whereas expression of mitogen-activated/ERK kinase 1/2 (MEK1/2), extracellular signal-regulated protein kinase 2 (ERK2), and activated ERK2 were significantly greater in the AF subjects. We propose that decreasing ACE2 expression during AF may affect the Ang II-dependent signaling pathway. In addition, our results suggest that atrial fibrosis in AF may be induced by antagonistic regulation between ACE and ACE2 expression. (c) 2007 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.
Determination of the interaction within polyester-based solid polymer electrolyte using FTIR spectroscopy
(2007-02-09)
Wu, I-Der
;
Chang, Feng-Chih
;
應用化學系
;
Department of Applied Chemistry
Characterization and interaction behavior between Li+ ion and C=O groups of a series polyester electrolyte have been thoroughly examined using Fourier transform infrared (FTIR). The "free/Li+ bonded" C=O absorptivity coefficient of the LiClO4/polyester can be determined quantitatively using FTIR spectrum ranging from 1800 to 1650 cm(-1) at 80 degrees C. Results from curve fitting show that the "free/Li+ bonded" C=O absorptivity coefficient is 0.144 +/- 0.005. The C=O group of polymer electrolyte shows strong interaction with Li+ ion and a limit value of 95% "Li-divided by bonded" C = O is approached in the polymer electrolyte system when the Li+ ion equivalent fraction is about 0.28. The molecular structure of polyester electrolyte does not affect significantly the efficiency of interaction between Li+ ion and C=O. (c) 2007 Published by Elsevier Ltd.
Metal nanocrystals as charge storage nodes for nonvolatile memory devices
(2007-02-10)
Yeh, P. H.
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Chen, L. J.
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Liu, P. T.
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Wang, D. Y.
;
Chang, T. C.
The memory effects of the metal nanocrystals were found to be more pronounced than those of the semiconductor nanocrystals. Various metal nanocrystals as charge storage nodes are reviewed. The memory effects have strong relationship with the work function, and the work function can be modulated by changing the metal species. By tunneling dielectrics engineering, the optimum I-GWrite/Erase/I-G Retention ratio can be obtained. (c) 2006 Elsevier Ltd. All rights reserved.
利用NMOS來保護混合電壓輸入輸出介面之電路
(2007-02-11)
柯明道
;
蔡佳昇
本發明係一種利用NMOS來保護混合電壓輸入輸出介面之電路，用以使不同電壓間的積體電路介面能順利溝通，由於習知技術的混合電壓輸入輸出介面電路複雜，為了使不同電壓間的積體電路介面能順利溝通而設計出十分複雜的保護混合電壓輸入輸出介面的電路，由於繁雜的設計，要組成保護混合電壓輸入輸出介面的電路所需使用的材料與種類與本發明相較之下的相對的較多，出於節省成本與提高混合電壓更大範圍(兩電壓間的差距更大)的考量，本發明係設計將NMOS和閘極追蹤電路加在傳統的輸入輸出介面上，這樣的輸入輸出介面可以容忍高於內部電壓源2~3倍值得訊號。
Copper phthalocyanine buffer layer to enhance the charge injection in organic thin-film transistors
(2007-02-12)
Chen, Fang-Chung
;
Kung, Li-Jen
;
Chen, Tung-Hsien
;
Lin, Yung-Sheng
;
光電工程學系
Copper phthalocyanine (CuPC) has been used as the buffer layer for source and drain electrodes to improve the performance of organic thin-film transistors. The mobility was improved by almost onefold after the modification. By incorporating with CuPC, the contact resistance was reduced, deduced from the line-transfer method. The higher hole current observed in the hole-only diode after adding CuPC further confirms the improvement of hole-injection efficiency. It is concluded that the device improvement is attributed to the reduction of contact resistance, which resulted from the Fermi level pinning at the induced gap states at the Au/CuPC interface. (c) 2007 American Institute of Physics.
Stability of continuous-wave laser-crystallized epilike silicon transistors
(2007-02-12)
Lin, Yu-Ting
;
Chen, Chih
;
Shieh, Jia-Min
;
Pan, Ci-Ling
;
材料科學與工程學系
Stability of high-hole-mobility thin-film transistors (TFTs) on single-grainlike silicon channels formed by continuous-wave laser crystallization during hot-carrier stressing (HCS) was studied. As channel layers become thicker, laser-mediated channel crystallinity increases, increasing channel roughness. On such epilike polycrystalline silicon substrates, the poorer interface quality for thicker channels, even those with lower tail-state densities of grain traps, is responsible for the extensive charge trapping and creation of deep-state densities in the fabricated TFTs due to HCS. Hence, on a thin channel with a thickness of 50 nm and ultrasmooth surfaces, HCS hardly degrades the electrical parameters of the devices. (c) 2007 American Institute of Physics.
Use of statistical methods to find the polysaccharide structural characteristics and the relationships between monosaccharide composition ratio and macrophage stimulatory activity of regionally different strains of Lentinula edodes
(2007-02-12)
Lo, Tiffany Chien Ting
;
Jiang, Yi Huei
;
Chao, Anne Lien Ju
;
Chang, Cheng Allen
;
生物科技學系
Multiple linear regression analysis was used to deduce the correlation between the monosaccharide composition ratios of 10 regionally different strains of Lentinula edodes and their in vitro macrophage stimulatory activities. Arabinose, xylose, mannose and galactose were identified as the monosaccharides that could be related to macrophage stimulatory activities. Additional principal component analysis and factor analysis methods were used to treat the same monosaccharide composition ratio data and the compositions of arabinose, xylose, mannose and galactose were found to be important. Interestingly, glucose, although presented in large compositions in all strains presumably forms the backbone of the polysaccharide structures, is not selected as the determinant factor for either structural characteristics or that of the in vitro macrophage stimulatory activities. (c) 2006 Elsevier B.V. All rights reserved.
Single photon emission from an InGaAs quantum dot precisely positioned on a nanoplane
(2007-02-12)
Hsieh, Tung-Po
;
Chyi, Jen-Inn
;
Chang, Hsiang-Szu
;
Chen, Wen-Yen
;
Hsu, Tzu Min
This work demonstrates single photon emissions from a site-controlled quantum dot (QD) grown on a self-constructed nanoplane. The size of the nanoplane on the micron-sized multifacet structure is accurately controlled by a low surface reducing rate (similar to 16 nm/min). Single QD spectral lines were resolved and identified. The antibunching behavior reveals that single photons are emitted from the positioned QD. (c) 2007 American Institute of Physics.
Improved hardness amplification in NP
(2007-02-12)
Lu, Chi-Jen
;
Tsai, Shi-Chun
;
Wu, Hsin-Lung
;
資訊工程學系
;
Department of Computer Science
We study the problem of hardness amplification in NP. We prove that if there is a balanced function in NP such that any circuit of size s(n) = 2(Omega(n)) fails to compute it on a 1/poly(n) fraction of inputs, then there is a function in NP such that any circuit of size s(n) fails to compute it on a 1/2 - 1/s'(n) fraction of inputs, with s'(n) = 2(Omega(n2/13)). This improves the result of Healy et al. (STOC'04), which only achievess s' (n) = 2(Omega(n1/2)) for the case with s(n) = 2(Omega(n)). (c) 2006 Elsevier B.V. All rights reserved.
Photodissociation dynamics of nitrobenzene and o-nitrotoluene
(2007-02-14)
Lin, Ming-Fu
;
Lee, Yuan T.
;
Ni, Chi-Kung
;
Xu, Shucheng
;
Lin, M. C.
Photodissociation of nitrobenzene at 193, 248, and 266 nm and o-nitrotoluene at 193 and 248 nm was investigated separately using multimass ion imaging techniques. Fragments corresponding to NO and NO2 elimination from both nitrobenzene and o-nitrotoluene were observed. The translational energy distributions for the NO elimination channel show bimodal distributions, indicating two dissociation mechanisms involved in the dissociation process. The branching ratios between NO and NO2 elimination channels were determined to be NO/NO2=0.32 +/- 0.12 (193 nm), 0.26 +/- 0.12 (248 nm), and 0.4 +/- 0.12(266 nm) for nitrobenzene and 0.42 +/- 0.12(193 nm) and 0.3 +/- 0.12 (248 nm) for o-nitrotoluene. Additional dissociation channels, O atom elimination from nitrobenzene, and OH elimination from o-nitrotoluene, were observed. New dissociation mechanisms were proposed, and the results are compared with potential energy surfaces obtained from ab initio calculations. Observed absorption bands of photodissociation are assigned by the assistance of the ab initio calculations for the relative energies of the triplet excited states and the vertical excitation energies of the singlet and triplet excited states of nitrobenzene and o-nitrotoluene. Finally, the dissociation rates and lifetimes of photodissociation of nitrobenzene and o-nitrotoluene were predicted and compared to experimental results. (c) 2007 American Institute of Physics.
Photodissociation dynamics of nitrobenzene and o-nitrotoluene
(2007-02-14)
Lin, Ming-Fu
;
Lee, Yuan T.
;
Ni, Chi-Kung
;
Xu, Shucheng
;
Lin, M. C.
Photodissociation of nitrobenzene at 193, 248, and 266 nm and o-nitrotoluene at 193 and 248 nm was investigated separately using multimass ion imaging techniques. Fragments corresponding to NO and NO2 elimination from both nitrobenzene and o-nitrotoluene were observed. The translational energy distributions for the NO elimination channel show bimodal distributions, indicating two dissociation mechanisms involved in the dissociation process. The branching ratios between NO and NO2 elimination channels were determined to be NO/NO2=0.32 +/- 0.12 (193 nm), 0.26 +/- 0.12 (248 nm), and 0.4 +/- 0.12(266 nm) for nitrobenzene and 0.42 +/- 0.12(193 nm) and 0.3 +/- 0.12 (248 nm) for o-nitrotoluene. Additional dissociation channels, O atom elimination from nitrobenzene, and OH elimination from o-nitrotoluene, were observed. New dissociation mechanisms were proposed, and the results are compared with potential energy surfaces obtained from ab initio calculations. Observed absorption bands of photodissociation are assigned by the assistance of the ab initio calculations for the relative energies of the triplet excited states and the vertical excitation energies of the singlet and triplet excited states of nitrobenzene and o-nitrotoluene. Finally, the dissociation rates and lifetimes of photodissociation of nitrobenzene and o-nitrotoluene were predicted and compared to experimental results. (c) 2007 American Institute of Physics.
Novel epoxy nanocomposite of low D-k introduced fluorine-containing POSS structure
(2007-02-15)
Wang, Yen-Zen
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Chen, Wen-Yi
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Yang, Chao-Chen
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Lin, Chen-Lung
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Chang, Feng-Chih
A nanoporous additives, polyhedral oilgomeric silisesquioxane containing eight functional hexafluorine groups, octakis(dimethylsiloxyhexafluoropropyl ether)silsesquioxane (OF) has been synthesized and blended with the UV-cured epoxy resin. The OF containing (10%) epoxy has significantly lower dielectric constant (2.65) than the plain epoxy (3.71). The incorporation of fluorine containing additives is well-known to reduce dielectric constant due to lower its polarizability. In addition, the presence of the bulky POSS structure is able to create additional free space or pores and further reduces the dielectric constant of the epoxy matrix. (c) 2007 Wiley Periodicals, Inc.
The effect of centaurein on interferon-gamma expression and Listeria infection in mice
(2007-02-15)
Chang, Shu-Lin
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Yeh, Hsu-Hua
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Lin, Yu-Shiun
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Chiang, Yi-Ming
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Wu, Tung-Kung
We previously found that centaurein enhanced IFN-gamma transcription in T cells. Here, we demonstrate that centaurein increased the IFN-gamma expression in T and NK cells and the serum IFN-gamma level in mice. Centaurein elevated the transcription of T-bet but not GATA-3, which is consistent with its effect on that of IFN-gamma but not IL-4. Additionally, centaurein effectively protected mice against Listeria infection. Moreover, centaurein per se or in combination with antibiotics could treat Listeria infection. Our mechanistic studies suggest that centaurein augments IFN-gamma expression via a transcriptional up-regulation of T-bet and that centaurein protects against or treats Listeria infection via a modulation of IFN-gamma expression. (c) 2006 Elsevier Inc. All rights reserved.
A competitive algorithm in searching for many edges in a hypergraph
(2007-02-15)
Chen, Ting
;
Hwang, Frank K.
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應用數學系
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Department of Applied Mathematics
We give a competitive algorithm to identify all d defective edges in a hypergraph with d unknown. Damaschke did the d = 1 case for 2-graphs, Triesch extended the d = 1 case to r-graphs, and Johann did the general d case for 2-graphs. So ours is the first attempt to solve the searching for defective edges problem in its full generality. Further, all the above three papers assumed d known. We give a competitive algorithm where d is unknown. (c) 2006 Elsevier B.V. All rights reserved.
監控薄膜厚度變化之方法
(2007-02-16)
趙于飛
;
王夢偉
;
郭俊儀
;
柳克強
;
林滄浪
本發明係揭露一種監控薄膜厚度變化之方法,係用於一相位調變式橢圓儀。此方法包含經由相位調變式橢圓儀及一訊號擷取系統獲得一薄膜之一直流訊號、一一倍頻及一二倍頻訊號,並將前述之訊號傳遞至一電腦裝置。再經由電腦裝置之一如儀控程式之程式以換算前述之訊號得到一橢圓參數。接著,引入橢圓參數以計算薄膜之一厚度週期解,並利用一數據化之一二維厚度表示法即時監控薄膜之厚度週期解的變化。同時,透過程式呈現此方法之一監控畫面於電腦裝置之一顯示單元上。
Effect of Al-trace degradation on Joule heating during electromigration in flip-chip solder joints
(2007-02-19)
Liang, S. W.
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Chiu, S. H.
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Chen, Chih
;
材料科學與工程學系
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Department of Materials Science and Engineering
This study investigates the mechanism for the abrupt increase in temperature at later stages of electromigration in flip-chip solder joints. It is found that electromigration also occurs in Al traces when stressed by 0.6 A at 100 degrees C. Three-dimensional thermoelectrical simulation by finite element analysis was carried out to simulate the temperature distribution in solder joints with and without degradation of the Al trace. It is found that the degradation of the Al trace has substantial effect on the Joule heating of solder joints. This model can explain the serious Joule heating effect in the later stages of electromigration. (c) 2007 American Institute of Physics.
Wavelength switching transition in quantum dot lasers
(2007-02-19)
Wang, Hsing-Yeh
;
Cheng, Hsu-Chieh
;
Lin, Sheng-Di
;
Lee, Chien-Ping
;
電子工程學系及電子研究所
Control and the selection of the ground state emission and/or the excited state emission of an InAs quantum dot laser have been demonstrated. By controlling the currents injected into each section of a two-section cavity, switching between the ground state emission and the excited state emission with a separation of 100 nm was achieved. With a constant total current, either ground state lasing (similar to 1.3 mu m), excited state lasing (similar to 1.2 mu m), or dual state lasing can be obtained simply by adjusting the current ratio between the two sections. (c) 2007 American Institute of Physics.
Double-pass high-gain low-noise EDFA over Sand C+L-bands by tunable fundamental-mode leakage loss
(2007-02-19)
Hung, Chi-Ming
;
Chen, Nan-Kuang
;
Lai, Yinchieh
;
Sien, Chi
;
光電工程學系
We demonstrate a high-gain low-noise double-pass tunable EDFA over S- and C+L-bands by discretely introducing fundamental-mode leakage loss in a 16-m-long standard C-band Er3+-doped fiber. The amplified spontaneous emission at the wavelengths of longer than 1530 nm can be substantially attenuated by the ASE suppressing filters to maintain high population inversion and to squeeze out the optical gain for S- band signals. When the filters are disabled, the gain bandwidth immediately returns back to the C+L-bands. Under S-band operation, a 37 dB small signal gain and a minimum 4.84 dB noise figure at 1486.9 nm are achieved with a 980 nm pump power of 154 mW. (c) 2007 Optical Society of America.