Browsing by Issue Date, starting with "2008-05-12"

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紅嘴麵包
(2008-05-12)
管管
Anisotropy of light extraction from GaN two-dimensional photonic crystals
(2008-05-12)
Lai, Chun-Feng
;
Chi, Jim-Yong
;
Kuo, Hao-Chung
;
Chao, Chia-Hsin
;
Hsueh, Han-Tsung
Angular distribution of light diffracted out of the plane of two-dimensional photonic crystals ( PhC) has been studied in the azimuthal direction with a specially designed waveguide structure. The optical images of the light extraction patterns from the guided photoluminescence light are obtained with laser excitation in the center of the annual structure made on GaN multilayer. For increasing lattice constant, symmetric patterns with varying number of petals according to the symmetry of the PhC are observed. The appearance and disappearance of the petals can be explained using the Ewald construction in the reciprocal space. The dependence of light extraction on the lattice constant and orientation, and incident angle are investigated. (C) 2008 Optical Society of America.
High quantum efficiency dots-in-a-well quantum dot infrared photodetectors with AlGaAs confinement enhancing layer
(2008-05-12)
Ling, H. S.
;
Wang, S. Y.
;
Lee, C. P.
;
Lo, M. C.
;
電子工程學系及電子研究所
We demonstrate the high quantum efficiency InAs/In(0.15)Ga(0.85)As dots-in-a-well (DWELL) quantum dot infrared photodetectors (QDIPs). A thin Al(0.3)Ga(0.7)As layer was inserted on top of the InAs quantum dots (QDs) to enhance the confinement of QD states in the DWELL structure. The better confinement of the electronic states increases the oscillation strength of the infrared absorption. The higher excited state energy also improves the escape probability of the photoelectrons. Compared with the conventional DWELL QDIPs, the quantum efficiency increases more than 20 times and the detectivity is about an order of magnitude higher at 77 K. (c) 2008 American Institute of Physics.
Spontaneous reduction of metal ions initiated by ethylenediamine-capped CdS nanowires: A sensing mechanism revealed
(2008-05-13)
Hsu, Yung-Jun
;
Lu, Shih-Yuan
;
Lin, Yi-Feng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Dynamics of the F(2) reaction with the simplest pi-bonding molecule
(2008-05-14)
Lu, Yu-Ju
;
Xie, Tingxian
;
Fang, Jing-Wen
;
Shao, Hua-Chieh
;
Lin, Jim J.
The reaction of F(2)+C(2)H(4) has been investigated with crossed molecular beam experiments and high level ab initio calculations. For a wide range of collision energies up to 11 kcal/mol, only one reaction channel could be observed in the gas phase. The primary products of this channel were identified as F+CH(2)CH(2)F. The experimental reaction threshold of collision energy was determined to be 5.5 +/- 0.5 kcal/mol. The product angular distribution was found to be strongly backward, indicating that the reaction time scale is substantially shorter than rotation. The calculated transition state structure suggests an early barrier; such dynamics is consistent with the small product kinetic energy release measured in the experiment. All experimental results consistently support a rebound reaction mechanism, which is suggested by the calculation of the intrinsic reaction coordinate. This work provides a clear and unambiguous description of the reaction dynamics, which may help to answer the question why the same reaction produces totally different products in the condensed phase. (C) 2008 American Institute of Physics.
Class-D driving method for stereo load
(2008-05-15)
Hu, Jwu-Sheng
;
Chen, Keng-Yuan
The present invention provides a class D amplifier and method for driving a tri-wired stereo amplifier. Additionally, the class D amplifier includes a first filter, a second filter, a processor, a 2D-quantitizer, a signal generator, and a logic circuit. The class D amplifier and method of the invention can reduce cost of production and increase processing efficiency. More particularly, the class D amplifier and method of the invention are processed in an optimal feedback mode, so as to reduce the reciprocal effect between the two channels, and avoid mismatch of the two amplifiers.
On the total variation, topological entropy and sensitivity for interval maps
(2008-05-15)
Juang, Jonq
;
Shieh, Shih-Feng
;
應用數學系
;
Department of Applied Mathematics
A concept related to total variation termed H-1 condition was recently proposed to characterize the chaotic behavior of an interval map f by Chen, Huang and Huang [G. Chen, T. Huang, Y. Huang, Chaotic behavior of interval maps and total variations of iterates, Internat. J. Bifur. Chaos 14 (2004) 2161-2186]. In this paper, we establish connections between H-1 condition, sensitivity and topological entropy for interval maps. First, we introduce a notion of restrictiveness of a piecewise-monotone continuous interval map. We then prove that H-1 condition of a piecewise-monotone continuous map implies the non-restrictiveness of the map. In addition, we also show that either H-1 condition or sensitivity then gives the positivity of the topological entropy of f. (C) 2007 Elsevier Inc. All rights reserved.
Video coding method using image data skipping
(2008-05-15)
Shih, Yen-Chi
;
Chang, Tian-Sheuan
The present invention discloses the video coding method using image data skipping. Said method detects whether the encoded macro-block has to be skipped and terminated by a likelihood ratio test prior to mode decision. Therefore, the computation burden such as motion estimating and compensating can be properly eliminated. In one embodiment, the skipping likelihood ratio is composed of the encoded block and its predictions associated with the skipping displacement. While the decision threshold adapts according to the mode decision and detection statistics, the false detection and rate-distortion are substantially preserved.
String Matching System and Method Using Bloom Filters to Achieve Sub-Linear Computation Time
(2008-05-15)
Lin, Po-Ching
;
Lin, Ying-Dar
;
Zheng, Yi-Jun
;
Lai, Yuan-Cheng
A string matching system includes a text string, a plurality of patterns, an m-byte search window and a plurality of Bloom filters, wherein the m-byte search window stands for an m-byte sub-string in the text string under inspection. Every Bloom filter comprises sub-strings of a plurality of patterns. These Bloom filters are queried for membership of the rightmost block in the search window to determine the shift length. The acceleration efficiency of matching many bytes can be achieved simultaneously by shifting the search window for many bytes. Meanwhile, the patterns are stored into an embedded memory through a memory-efficient mechanism-the Bloom filter.
Evaluating the performance improvement of differential phase-shift keying signals by amplitude regeneration and phase-noise suppression
(2008-05-15)
Wei, Chia-Chien
;
Chen, Jason
;
Chen, Yung Jui
;
光電工程學系
;
Department of Photonics
Theoretical bit error rates of the differential phase-shift keying format with various regeneration schemes is presented. A comparison with ideal regeneration reveals that averaging the phase noise of adjacent bits is found to eliminate most penalties that are induced by phase noise. (C) 2008 Optical Society of America.
Three-dimensional simulation studies on electrostatic predictions for carbon nanotube field effect transistors (vol 177, pg 683, 2007)
(2008-05-15)
Chen, P. -Y.
;
Shao, Y. -L.
;
Cheng, K. -W.
;
Hsu, K. -H.
;
Wu, J. -S.
Crystal structure of a secondary vitamin D(3) binding site of milk beta-lactoglobulin
(2008-05-15)
Yang, Ming-Chi
;
Guan, Hong-Hsiang
;
Liu, Ming-Yih
;
Lin, Yih-Hung
;
Yang, Jinn-Moon
beta-lactoglobulin (beta-LG), one of the most investigated proteins, is a major bovine milk protein with a predominantly beta structure. The structural function of the only alpha-helix with three turns at the C-terminus is unknown. Vitamin D(3) binds to the central calyx formed by the beta-strands. Whether there are two vitamin D binding-sites in each beta-LG molecule has been a subject of controversy. Here, we report a second vitamin D(3) binding site identified by synchrotron X-ray diffraction (at 2.4 angstrom resolution). In the central calyx binding mode, the aliphatic tail of vitamin D(3) clearly inserts into the binding cavity, where the 3-OH group of vitamin D(3) binds externally. The electron density map suggests that the 3-OH group interacts with the carbonyl of Lys-60 forming a hydrogen bond (2.97 angstrom). The second binding site, however, is near the surface at the C-terminus (residues 136-149) containing part of an a-helix and a beta-strand I with 17.91 angstrom in length, while the span of vitamin D(3) is about 12.51 angstrom. A remarkable feature of the second exosite is that it combines an amphipathic alpha-helix providing nonpolar residues (Phe-136, Ala-139, and Leu-140) and a beta-strand providing a nonpolar (Ile-147) and a buried polar residue (Arg-148). They are linked by a hydrophobic loop (Ala-142, Leu-143, Pro-144, and Met-145). Thus, the binding pocket furnishes strong hydrophobic force to stabilize vitamin D(3) binding. This finding provides a new insight into the interaction between vitamin D(3) and beta-LG, in which the exosite may provide another route for the transport of vitamin D(3) in vitamin D(3) fortified dairy products. Atomic coordinates for the crystal structure Of beta-LG-vitamin D(3) complex described in this work have been deposited in the PDB (access code 2GJ5).
Dynamics and reversibility of oxygen doping and de-doping for conjugated polymer
(2008-05-15)
Liao, Hua-Hsien
;
Yang, Chia-Ming
;
Liu, Chien-Cheng
;
Horng, Sheng-Fu
;
Meng, Hsin-Fei
We perform comprehensive long-time monitoring of the p-doping and de-doping of poly(3-hexyl thiophene) under changing external conditions of oxygen, light, and temperature. They are shown to be controlled by the complex adsorption and desorption process with time scales ranging from seconds to weeks. The oxygen doping at atmospheric pressure takes several hours in the dark. The doping is dramatically accelerated to be within seconds with light of wavelength of 500-700 nm. Even at low oxygen pressure of 10(-4) torr doping occurs within minutes with light. The de-doping by oxygen desorption takes as long as weeks at room temperature and vacuum of 10(-4) torr, but when the temperature is raised to near the polymer glass temperature of 370 K, the de-doping is accelerated to minutes as the enhanced chain motion releases the trapped oxygen. Even though visible and near infrared light causes very efficient doping within seconds or minutes depending on vacuum level, such light-induced doping is not a chemical reaction and is fully reversible by thermal annealing at the end without sacrificing the mobility. For the polymer field-effect transistors, only the carrier density is changed while the mobility remains roughly a constant for all the conditions. (c) 2008 American Institute of Physics.
Effects of growth temperature on InN/GaN nanodots grown by metal organic chemical vapor deposition
(2008-05-15)
Chang, Wen-Hao
;
Ke, Wen-Cheng
;
Yu, Shu-Hung
;
Lee, Lin
;
Chen, Ching-Yu
InN nanodots grown on GaN by metal organic chemical vapor deposition using conventional growth mode as well as flow-rate modulation epitaxy at various growth temperatures (550-730 degrees C) were investigated. We found that different precursor injection schemes together with the effect of growth temperatures greatly influenced the surface morphology of InN nanodots and their photoluminescence (PL) properties. The sample grown at around 650 degrees C showed the highest growth rate. For samples grown at higher temperatures, the residual carrier concentration was reduced and the PL efficiency was improved. Furthermore, we found that the growth of InN nanodots is still sustainable even at a temperature higher than 700 degrees C while retaining their optical quality. (c) 2008 American Institute of Physics.
Cesium carbonate as a functional interlayer for polymer photovoltaic devices
(2008-05-15)
Chen, Fang-Chung
;
Wu, Jyh-Lih
;
Yang, Sidney S.
;
Hsieh, Kuo-Huang
;
Chen, Wen-Chang
The device characteristics of polymer solar cells with cesium carbonate (Cs(2)CO(3)) as an electron-injection interlayer have been investigated. It is found that the insertion of Cs(2)CO(3) at the cathode interface improves the device power conversion efficiency from 2.3% to 3.1%. In order to further understand the mechanism, the interfacial interaction between the active organic layer and the cathode was studied by x-ray photoemission spectroscopy (XPS). The results of XPS measurement indicate the fact that a portion of electrons transfer from the interlayer into the organic layer, resulting in n-type doping. The n-doping effect enhances the efficiency of electron injection and collection. Further, the maximum open-circuit voltage (V(oc)) was determined from its temperature dependence. For the device with Cs(2)CO(3), the maximum V(oc) is extremely close to the corresponding value of the energy difference between the highest occupied molecular orbital of the electron donor and the lowest unoccupied molecular orbital of the electron acceptor, suggesting a better Ohmic contact. All evidences indicated that Cs(2)CO(3) is a promising candidate as an interlayer to improve the device performance. (C) 2008 American Institute of Physics.
整合多種解析度影像之影像處理系統
(2008-05-16)
洪一平
;
葉韋賢
在整合多種解析度影像之影像處理系統中,主要以不同解析度影像擷取裝置擷取觀測場景中的影像,並利用不同解析度呈像裝置分別且整合地呈現相對於觀測場景之場景影像,。為達到兩個不同解析度影像源可無縫地被呈像出來,主要利用影像擷取裝置之間的座標轉換、呈像裝置之間的座標轉換,使得整個影像擷取、呈像可以如同單一影像擷取源、單一呈像手段般的情況。
檢測複製影像資料之視訊編碼方法
(2008-05-16)
史彥
;
張添烜
本發明係揭示一種檢測複製影像資料之視訊編碼方法。藉由似然率檢定預先決策複製影像資料及編碼過程可否終止,因此可摒除視訊編碼裝置之位移估測與位移補償等冗餘運算。實施例中,區塊複製似然率由編碼區塊及預測位移對應之預測區塊計算;為限制誤檢率以維持編碼率-失真表現,決策臨界由預測及檢測統計量動態的調整。
利用Bloom　filter達到次線性運算時間的字串比對系統及方法
(2008-05-16)
林柏青
;
林盈達
;
鄭伊君
;
賴源正
本發明係揭露一種字串比對系統,其包含一待測字串、複數個特徵字串、一M位元組搜尋視窗及複數個過濾模組。其中,M位元組搜尋視窗係用以由待測字串中擷取一M位元組字串,而每一過濾模組係包含複數個特徵字串之子字串,用以與M位元組字串進行比對,以輸出M位元組搜尋視窗之一位移長度。藉由一次移動搜尋視窗多個位元組,可達到同時比對多個位元組的加速效果。同時,利用Bloom filter這種較節省空間的儲存特徵字串方式,可以讓大量的特徵字串能存在單一晶片的內嵌式記憶體當中。
交大十二舍斷網
(2008-05-18)
蘇芳儀
;
Department of Communication and Technology
;
傳播與科技學系
十二舍斷網
《Korn》Nu-metal指標性樂團
(2008-05-18)
蔡昇峰
;
Department of Communication and Technology
;
傳播與科技學系
樂評(FLASH)