Browsing by Issue Date, starting with "2012-09-05"

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Symbol-based iterative decoding of convolutionally encoded multiple descriptions
(2012-09-05)
Wu, C. -F.
;
Chang, W. -W.
;
傳播研究所
;
Institute of Communication Studies
Transmission of convolutionally encoded multiple descriptions over noisy channels can benefit from the use of iterative source-channel decoding. The authors first modified the BCJR algorithm in a way that symbol a posteriori probabilities can be derived and used as extrinsic information to improve the iterative decoding between the source and channel decoders. The authors also formulate a recursive implementation for the source decoder that processes reliability information received on different channels and combines them with inter-description correlation to estimate the transmitted quantiser index. Simulation results are presented for two-channel scalar quantisation of Gauss-Markov sources which demonstrate the error-resilience capabilities of symbol-based iterative decoding.
交大e-News第125期
(2012-09-05)
Secretariat
;
國立交通大學秘書室
Effects of thiophene units on substituted benzothiadiazole and benzodithiophene copolymers for photovoltaic applications
(2012-09-05)
Ding, Ping
;
Zou, Yingping
;
Chu, Cheng-Che
;
Xiao, Dequan
;
Hsu, Chain-Shu
Two conjugated copolymers, poly{4,7-[5,6-bis(octyloxy)]benzo(c)(1,2,5)thiadiazole-alt-4,8-di(2-ethylhexyloxyl)benzo[1,2-b:3,4-b]dithiophene} (P1) and poly(2-{5-[5,6-bis(octyloxy)-4-(thiophen-2-yl)benzo(c)(1,2,5)thiadiazol-7-yl] thiophen-2-yl}-4,8-di(2-ethylhexyloxyl)benzo(1,2-b:3,4-b)dithiophene) (P2), composed of benzodithiophene and 5,6-dioctyloxybenzothiadiazole derivatives with or without thiophene units were synthesized via a Stille cross-coupling polymerization reaction. These copolymers are promising for applications in bulk heterojunction solar cells because of their good solubility, proper thermal stability, moderate hole mobility, and low band gap. The photovoltaic properties of these copolymers were investigated on the basis of blends of the different polymer/(6,6)-phenyl-C71-butyric acid methyl ester (PC71BM) weight ratios under AM1.5G illumination at 100 mW/cm2. The device with indium tin oxide/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)/P2:PC71BM (1 : 2 w/w)/Ca/Al gave a relatively better photovoltaic performance with a power conversion efficiency of 1.55%. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Quantum Switching of pi-Electron Rotations in a Nonplanar Chiral Molecule by Using Linearly Polarized UV Laser Pulses
(2012-09-05)
Mineo, Hirobumi
;
Yamaki, Masahiro
;
Teranishi, Yoshiaki
;
Hayashi, Michitoshi
;
Lin, Sheng Hsien
Nonplanar chiral aromatic molecules are candidates for use as building blocks of multidimensional switching devices because the pi electrons can generate ring currents with a variety of directions. We employed (P)-2,2'-biphenol because four patterns of pi-electron rotations along the two phenol rings are possible and theoretically determine how quantum switching of the it-electron rotations can be realized. We found that each rotational pattern can be driven by a coherent excitation of two electronic states under two conditions: one is the symmetry of the electronic states and the other is their relative phase. On the basis of the results of quantum dynamics simulations, we propose a quantum control method for sequential switching among the four rotational patterns that can be performed by using ultrashort overlapped pump and dump pulses with properly selected relative phases and photon polarization directions. The results serve as a theoretical basis for the design of confined ultrafast switching of ring currents of nonplanar molecules and further current-induced magnetic fluxes of more sophisticated systems.
Metallic conduction and large electron-phonon-impurity interference effect in single TiSi nanowires
(2012-09-05)
Hsu, Wei-Che
;
Chen, Chao-Chun
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Lin, Yong-Han
;
Lin, Huang-Kai
;
Chiu, Hsin-Tien
We report on the first electrical characterizations of single-crystalline TiSi nanowires (NWs) synthesized by chemical vapor deposition reactions. By utilizing the focused-ion-beam-induced deposition technique, we have delicately made four-probe contacts onto individual NWs. The NW resistivities have been measured between 2 and 300 K, which reveal overall metallic conduction with small residual resistivity ratios in the NWs. Surprisingly, we find that the effect due to the interference processes between the elastic electron scattering and the electron-phonon scattering largely dominates over the usual Boltzmann transport even at room temperature. Such prominent electron-phonon-impurity interference effect is ascribed to the presence of large amounts of disorder and high Debye temperatures in TiSi NWs.
BIOCHEMICAL SENSOR AND METHOD OF MANUFACTURING THE SAME
(2012-09-06)
ZAN Hsiao-Wen
;
Tsai Chuang-Chuang
;
Meng Hsin-Fei
;
Yeh Chun-Cheng
;
Dai Ming-Zhi
A biochemical sensor and a method of manufacturing the same are disclosed. The biochemical sensor includes a substrate, a gate arranged on one side of the substrate, a gate insulating layer arranged on one side of the gate opposite to the substrate, an active layer arranged on one side of the gate insulating layer opposite to the gate, a source and a drain arranged on one side of the active layer opposite to the gate insulating layer, and a biochemical sensing layer arranged on one side of the active layer opposite to the gate insulating layer and between the source and the drain.
Ag-Nanoparticle-Decorated SiO2 Nanospheres Exhibiting Remarkable Plasmon-Mediated Photocatalytic Properties
(2012-09-06)
Chen, Kuang-Hsiu
;
Pu, Ying-Chih
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Chang, Kao-Der
;
Liang, Yi-Fan
;
Liu, Chia-Ming
We demonstrated for the first time that Ag-nanoparticle-decorated SiO2 nanospheres (NSs) may display noticeable photocatalytic activities upon surface plasmon resonance (SPR) excitation. The samples were prepared by reacting SiO2 NSs with AgNO3 in the seed-mediated growth process, from which the Ag particle size and decoration density can be readily controlled. The dependence of the SPR-mediated photocatalytic performance of Ag-decorated SiO2 NSs on the Ag morphology was investigated and presented. The as-prepared Ag-decorated SiO2 NSs showed a significantly red shifted and relatively broad SPR absorption when compared with the individually dispersed Ag nanoparticles. Owing to the considerably broad SPR absorption that spanned from the visible to the near-infrared region, Ag-decorated SiO2 NSs surpassed N-doped P-25 TiO2 powder and individually dispersed Ag nanoparticles in photocatalytic activity, demonstrating their potential as an active photocatalyst in nearly all the current photocatalysis applications. Furthermore, the result of performance evaluation under natural sunlight shows that the present Ag-decorated SiO2 NSs can be used as highly efficient photocatalysts that may practically harvest energy from sunlight. The current study provides a new paradigm for designing plasmonic metal nanostructures that can effectively absorb the entire solar spectrum and beyond for solar fuel generation.
Light extraction efficiency of GaN-based LED with pyramid texture by using ray path analysis
(2012-09-10)
Pan, Jui-Wen
;
Wang, Chia-Shen
;
光電系統研究所
;
影像與生醫光電研究所
;
生醫電子轉譯研究中心
We study three different gallium-nitride (GaN) based light emitting diode (LED) cases based on the different locations of the pyramid textures. In case 1, the pyramid texture is located on the sapphire top surface, in case 2, the pyramid texture is locate on the P-GaN top surface, while in case 3, the pyramid texture is located on both the sapphire and P-GaN top surfaces. We study the relationship between the light extraction efficiency (LEE) and angle of slant of the pyramid texture. The optimization of total LEE was highest for case 3 among the three cases. Moreover, the seven escape paths along which most of the escaped photon flux propagated were selected in a simulation of the LEDs. The seven escape paths were used to estimate the slant angle for the optimization of LEE and to precisely analyze the photon escape path. c (C)2012 Optical Society of America
Enhancing threshold voltage of AlGaN/GaN high electron mobility transistors by nano rod structure: From depletion mode to enhancement mode
(2012-09-10)
Xuan, Rong
;
Kuo, Wei-Hong
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Hu, Chih-Wei
;
Lin, Suh-Fang
;
Chen, Jenn-Fang
This paper presents an approach in fabricating normally off AlGaN/GaN high electron mobility transistors (HEMTs). The fabrication technique was based on the carbon-doped GaN epitaxy layers on silicon substrate and the nano rod structure of the gate region in AlGaN/GaN HEMTs. Using this method, the threshold voltage of AlGaN/GaN HEMTs can be shifted from -2 V in a conventional depletion-mode (D-mode) AlGaN/GaN HEMT to 2 V in an enhancement-mode (E-mode) AlGaN/GaN HEMT. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4752113]
Method of compensating for pixel migration in volume holographic optical disc (VHOD)
(2012-09-10)
Yu, Yeh-Wei
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Cheng, Chih-Yuan
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Teng, Tun-Chien
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Chen, Cheng-Hsien
;
Lin, Shiuan-Huei
Volume holographic optical disc (VHOD) technology is simpler than the angular multiplexing holographic system. However, disc rotation usually causes pixel migration, thus reducing signal quality. This study proposes a special geometrical arrangement to counteract pixel migration. Using paraxial approximation analysis, an optimal geometrical distance ratio, K, is calculated to compensate for pixel migration and improve image quality during disc rotation. The results of approximation analysis are confirmed by both simulation and experimental results. (C) 2012 Optical Society of America
Dehydroxyl effect of Sn-doped silicon oxide resistance random access memory with supercritical CO2 fluid treatment
(2012-09-10)
Tsai, Tsung-Ming
;
Chang, Kuan-Chang
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Chang, Ting-Chang
;
Syu, Yong-En
;
Liao, Kuo-Hsiao
The tin-doped can supply conduction path to induce resistance switching behavior. However, the defect of tin-doped silicon oxide (Sn:SiOx) increased the extra leakage path lead to power consumption and joule heating degradation. In the study, supercritical CO2 fluids treatment was used to improve resistive switching property. The current conduction of high resistant state in post-treated Sn:SiOx film was transferred to Schottky emission from Frenkel-Poole due to the passivation effect. The molecular reaction model is proposed that the defect was passivated through dehydroxyl effect of supercritical fluid technology, verified by material analyses of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4750235]
Sub-10-fs deep-ultraviolet light source with stable power and spectrum
(2012-09-10)
Kida, Yuichiro
;
Okamura, Kotaro
;
Liu, Jun
;
Kobayashi, Takayoshi
;
電子物理學系
In some applications of ultrafast spectroscopy that employ sub-10-fs pulses, the pulse spectrum and power need to be stable for several tens of minutes. In this study, we generate sub-10-fs deep-ultraviolet (DUV) pulses with such stabilities by chirped-pulse four-wave mixing. A power fluctuation of less than 3% rms was realized by employing stabilization schemes that employ a power stabilizer. The pulses generated in this study have been applied to transient absorption spectroscopy in the DUV with a sub-10-fs time resolution [Phys. Chem. Chem. Phys. 14, 6200 (2012).]. This sub-10-fs DUV source has a similar performance to widely used noncollinear optical parametric amplifiers. (c) 2012 Optical Society of America
Dual positive-feedbacks voltage controlled oscillator
(2012-09-11)
Huang Zue-Der
;
Wu Chung-Yu
A dual positive-feedbacks voltage controlled oscillator includes an oscillation circuit and a cross coupled pair circuit. The oscillation circuit includes a first transistor, a second transistor, an inductor and a plurality of capacitors. The gates of the first and second transistors are opposite to each other and coupled to two points of the inductor. The inductor and the capacitors are formed as a LC tank. The cross coupled pair circuit includes a third transistor and a fourth transistor. The gates of the third and fourth transistors are cross coupled to two points of the inductor. Thereby, the gate of the third transistor is coupled to the gate of the second transistor; the gate of the fourth transistor is coupled to the gate of the first transistor; the drain of the third transistor is coupled to the source of the first transistor; and the drain of the fourth transistor is coupled to the source of the second transistor.
入侵者偵測系統及方法
(2012-09-11)
宋開泰
;
林嘉豪
;
林志昇
;
楊舒涵
本發明為一結合無線感測網路與保全機器人之入侵者偵測系統。於環境中佈建之無線感測模組，可以多重感測型式偵測各節點附近是否有入侵者或異常狀況，並透過網狀無線網路傳送給保全監控中心及保全機器人。機器人具有在環境中自主運動的能力，在偵測到異狀或警報觸發時前往問題發生點察看，並透過無線網路即時將影像資訊傳送到保全人員及主人之行動裝置上，可以及時得知現場狀況，達到保全之功效。
Hollow sphere from amphiphilic chitosan derivatives and method of preparing amiphiphilic chitosan derivative complex for medical use
(2012-09-11)
Chen San-Yuan
;
Liu Kun-Ho
;
Liu Dean-Mo
A hollow sphere from amphiphilic chitosan derivatives and a method of preparing an amphiphilic chitosan derivative complex for medical use are disclosed, and the hollow sphere from amphiphilic chitosan derivatives comprises: chitosan derivatives represented by the following formula (I), which self-assemble and form a hollow sphere in a solvent;wherein, each R1 is independently hydrogen, C1˜C4 alkyl, C1˜C6 carboxyl, sulfate group, or phosphate group, each R2 is independently hydrogen, C1˜C12 alkyl, C1˜C6 carboxyl, or C2˜C12 acyl group, and m is an integer of 100-2000.
以介電泳為基礎的微流體系統
(2012-09-11)
范士岡
一種以介電泳為基礎的微流體系統，包括：一第一電極平板，其具有一第一基板及一電極層，電極層設置於第一基板的一側面；一第二電極平板，其具有一第二基板及多數個電極，該些電極設置於第二基板的一側面，並且與電極層相對，該些電極依據一微流道圖案排列；以及一分隔結構，其設置於第一電極平板與第二電極平板之間，使得第一電極平板與第二電極平板之間形成一空間。藉此，使用者可將微流體注入至空間中，然後對不同的電極施加電壓，即可驅動微流體往不同處流動。
利用斜向沈積形成之奈米結構薄膜及其方法
(2012-09-11)
張家華
;
楊勁生
;
邱清華
;
余沛慈
;
郭浩中
本發明提出了一種利用斜向沈積技術形成之透明導電氧化物奈米結構及其方法。該方法使用電子槍來蒸鍍靶材，其蒸鍍基板設置在多個可轉動傾斜的平板上，並具有氣體控制閥控制氣體的通入，及一加熱源控制腔體內溫度，並於蒸鍍後進行退火製程，以改善薄膜結構與光電性質。
Multilayer substrate having gallium nitride layer and method for forming the same
(2012-09-11)
Chang Edward Yi
;
Hsiao Yu-Lin
;
Lu Jung-Chi
The present invention provides a method for forming a multilayer substrate having a gallium nitride layer, wherein a mesh layer having a plurality of openings is formed on a substrate, and a buffer layer, three aluminum gallium nitride layers with different aluminum concentrations and a gallium nitride layer are formed in sequence on the substrate in the openings. The three aluminum gallium nitride layers with different aluminum concentrations are capable of releasing stress, decreasing cracks on the surface of the gallium nitride layer and controlling interior defects, such that the present invention provides a gallium nitride layer with larger area, greater thickness, no cracks and high quality for facilitating the formation of high performance electronic components in comparison with the prior art. The present invention further provides a multilayer substrate having a gallium nitride layer.
升降壓式電源轉換器及其控制方法
(2012-09-11)
陳科宏
;
吳緯權
;
何心欣
一種升降壓式電源轉換器及其控制方法，其在該電源轉換器的輸入電壓接近輸出電壓時延長開關的切換週期並使用新的開關順序來改善切換損失及導通損失，並且考慮負載電流對責任週期的影響使其可在正確點切換模式，因此該輸出電壓不會因為改變模式而受影響。
STATIC RANDOM ACCESS MEMORY CELL AND METHOD OF OPERATING THE SAME
(2012-09-13)
Chiu Yi-Te
;
Chang Ming-Hung
;
Yang Hao-I
;
Hwang Wei
A static random access memory cell includes a latch unit. The latch unit includes a bi-inverting circuit and a switching circuit. The bi-inverting circuit has a first terminal and a second terminal. The switching circuit is electrically connected between the first terminal and the second terminal, wherein when the switching circuit is turned on, the switching circuit forms a feedback between the first terminal and the second terminal for latching the latch unit; and when the switching circuit is turned off, the feedback is removed to cause the SRAM cell to write a data bit to the latch unit.