Browsing by Issue Date, starting with "2004-01-06"

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Design of a broadband active silencer using mu-synthesis
(2004-01-06)
Bai, MR
;
Zeung, PS
;
機械工程學系
;
Department of Mechanical Engineering
A robust spatially feedforward controller is developed for broadband attenuation of noise in ducts. To meet the requirements of robust performance and robust stability in the presence of plant uncertainties, a mu-synthesis procedure via D-K iteration is exploited to obtain the optimal controller. This approach considers uncertainties as modelling errors of the nominal plant in high frequency and is implemented using a floating point digital signal processor (DSP). Experimental investigation was undertaken on a finite-length duct to justify the proposed controller. The mu- controller is compared to other control algorithms such as the H-2 method, the H-infinity method and the filtered-U least mean square (FULMS) algorithm. Experimental results indicate that the proposed system has attained 25.8 dB maximal attenuation in the band 250-650 Hz. (C) 2003 Elsevier Science Ltd. All rights reserved.
開關式H型功率驅動器開關狀態偵測電路及其應用於延時保護與延時偵測電路
(2004-01-11)
翁會禮
;
廖德誠
本創作係一種開關式H型功率驅動器開關狀態偵測電路及其應用於延時保護與延時偵測電路，其主要創新在於不用外加感測元件，而利用半導體開關元件之端電壓(例如，MOS元件之VDS、或BJT及IGBT之VCE)在開(ON)或關(OFF)截然不同之數值可對應於開或關之狀態，應用於動態偵測開關元件之開關狀態；本創作並將所偵測之結果實際應用於保護開關式半導體驅動器同一臂(Arm)之各開關元件，避免同時導通造成短路電流過大燒毀開關元件；並可提供數位控制器精確的開關延遲時間，作為數位控制器延時保護制定對策之參考；上述兩個應用可互為獨立亦可同時並行支援。
小影子
(2004-01-12)
管管
Tuning of wavelengths: Synthesis and photophysical studies of iridium complexes and their applications in organic light emitting devices
(2004-01-13)
Laskar, IR
;
Chen, TM
;
應用化學系
;
Department of Applied Chemistry
We have prepared and characterized a series of substituted 2-phenylbenzthiazole (4-CF3, 4-Me, 4-OMe, 4-F, 4-CN, and 3-F) ligands. The intermediate di-irrido and the six-coordinated mononuclear iridium(III) dopants of the above ligands have been synthesized and characterized. These complexes are thermally stable between 275 and 300 degreesC depending upon the types and volatility of substituents. They emit bright yellow to orange light. The peak emission wavelengths of the dopants can be finely tuned depending upon the electronic properties of the substituents as well as their positions in the ring. In the absorption spectra, the (MLCT)-M-1 and (MLCT)-M-3 transitions have been resolved in the range of 385-450 nm. The long tail toward lower energies are assigned to (MLCT)-M-3 and (3)pi-pi(*) transitions, which gains intensity by mixing with the higher lying (MLCT)-M-1 state through the spin-orbit coupling of iridium(III). All complexes exhibit one electron oxidation and the oxidation potential values can be correlated with the Hammett substituent constants. The electroluminescent characteristics for the substituted and the unsubstituted complexes have been compared and discussed.
Thermal properties, interactions, morphologies, and conductivity behavior in blends of poly(vinylpyridine)s and zinc perchlorate
(2004-01-13)
Kuo, SW
;
Wu, CH
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
We have investigated the physical properties and specific interaction of two regioisomeric poly(vinylpyridine)s-poly(2-vinylpyridine) (P2VP) and poly(4-vinylpyridine) (P4VP)-blended with zinc perchlorate. Analyses by differential scanning calorimetry indicate that the values of T-g of the poly(vinylpyridine)s increase significantly upon blending with zinc perchlorate. The values of Tg of P2VP and P4VP increase by 119 and 154 degreesC, respectively, relative to their corresponding pure polymers, upon blending with 40 and 30 wt %, respectively, zinc perchlorate. On the basis of the extended configuration entropy model equation, the interaction strength of the zinc salt/P4VP blend (3.60) is greater than that of the zinc salt/P2VP blend (3.55). The interaction between the polymer and the zinc ion was confirmed by infrared, X-ray photoelectron, and solid-state NMR spectroscopies, which suggest that the zinc cation coordinates to pyridine units in a metal-ligand bonding mode. In addition, the strength of the interaction between the polymer and the zinc ion is influenced by the different steric demands of the two polymer structures. A good correlation is found in the morphology of these polymer/zinc salt blends as determined by wide-angle X-ray diffraction and solid-state NMR T-1rho(H) measurements.
Hydrogen bonding effect on the poly(ethylene oxide), phenolic resin, and lithium perchlorate-based solid-state electrolyte
(2004-01-15)
Chen, HW
;
Jiang, CH
;
Wu, HD
;
Chang, FC
;
應用化學系
The interaction behavior of solid-state polymer electrolytes composed of poly(ethylene oxide) (PEO)/novolac-type phenolic resin and lithium perchlorate (Li-ClO4) was investigated in detail by DSC, FTIR, ac impedance, DEA, solid-state NMR, and TGA. The hydrogen bonding between the hydroxyl group of phenolic and ether oxygen of the PEO results in higher basicity of the PEO. The higher basicity of the ether group can dissolve the lithium salts more easily and results in a greater fraction of "free" anions and thus higher ionic conductivity. DEA results demonstrated that addition of the phenolic increases the dielectric constant because of the partially negative charge on the ether group induced by the hydrogen bonding interaction between ether oxygen and the hydroxyl group. The study showed that the blend of PEO(100)/LiClO4(25)/phenolic(15) possesses the highest ionic conductivity (1.5 X 10(-5) S cm(-1)) with dimensional stability. (C) 2003 Wiley Periodicals, Inc.
Novel polymer electrolyte composed of poly(ethylene oxide), lithium triflate, and benzimidazole
(2004-01-15)
Chen, HW
;
Xu, HY
;
Huang, CF
;
Chang, FC
;
應用化學系
This work has demonstrated that the incorporation of benzimidazole derivatives, 2,2'-p-phenylene-bisindole (PPBI), enhances the ionic conductivity of a poly(ethylene oxide) (PEO)-based electrolyte by 20 times more than the plain system. Specific interactions among amino group, ethyl oxide, and lithium cation were investigated using differential scanning calorimetry (DSC), FTIR, and alternating current impedance. The DSC characterization confirms that the initial addition of PPBI is able to enhance the PEO crystallinity attributed to the interaction between the negative charge from the amino group and the lithium cation. Three types of complexes are present: complex I is present in the PEO phase, complex 11 resides at interphase, and complex III is located within the PPBI domain. Complex II plays the key role in stabilizing these two microstructure phases. FTIR spectra confirm that because of the presence of PPBI one is able to dissolve lithium salts more easily than in the plain electrolyte system and thus increase the fraction of free ions. (C) 2003 Wiley Periodicals, Inc.
Active electrostatic discharge (ESD) device for on-chip ESD protection in sub-quarter-micron complementary metal-oxide semiconductor (CMOS) process
(2004-01-15)
Ker, MD
;
Tseng, TK
;
電機學院
;
College of Electrical and Computer Engineering
A novel electrostatic discharge (ESD) protection device with a threshold voltage of similar to0V for complementary metal-oxide semiconductor (CMOS) integrated circuits in sub-quarter-micron CMOS technology is proposed. Quite different to the traditional ESD protection devices, such an active ESD device is originally standing in its turn-on state when the IC is zapped under ESD events. Therefore, such an active ESD device has the fastest turn-on speed and the lowest turn-on voltage to effectively protect the internal circuits with a much thinner gate oxide in future sub-0.1 mum CMOS technology. The proposed active ESD device is fully process-compatible to the general sub-quarter-micron CMOS process.
Integration of a stack of two fluorine doped silicon oxide film with ULSI interconnect metallization
(2004-01-15)
Cheng, YL
;
Wang, YL
;
Liu, CP
;
Wu, YL
;
Lo, KY
Recently, fluorosilicate glass (FSG) has received much attention for application in microelectronics manufacturing due to its low dielectric constant and stable gap-filling ability. Although FSG films have been demonstrated as potential inter metal dielectrics (IMD) for sub-micron devices, integrating a stack of two fluorine doped silicon oxide film deposited on a high-density plasma chemical vapor deposition (HDP-CVD) system for gap filling and a plasma-enhanced chemical vapor deposition (PECVD) system for throughput has not been fully investigated. In this research, an excellent and exceptionally stable process was demonstrated for a stack of HDP-CVD FSG and PECVD FSG layers. Cracks that result from multi-level metal technology were eliminated when higher compressive stress PECVD FSG film was implemented as a capping layer. An 11% capacitance reduction was achieved when comparing a stack of FSG films to undoped silicon oxide. No problem occurred for photo, via etching and chemical mechanical polishing of FSG film. The FSG layer stack's via resistance (Rc(-)Via) as well as a full HDP-FSG scheme is comparable. These results are very promising for the integration of FSG films as inter metal dielectric for devices. (C) 2003 Elsevier B.V. All rights reserved.
Characteristics of stable emission GaN-based resonant-cavity light-emitting diodes
(2004-01-19)
Lin, CF
;
Yao, HH
;
Lu, JW
;
Hsieh, YL
;
Kuo, HC
The resonant-cavity light-emitting diode (RC-LED) structure was grown by MOCVD. The structure of RC-LED consisted of a 3lambda InGaN/GaN MQW LED cavity between the top TiO2/SiO2 DBR (81.7%, reflectance) and the bottom AlN/GaN DBR (90.4%) stack. A stable 410 nm emission peak and a low thermally induced red-shift effect (0.12 nm/kA/cm(2)) were measured by varying the injection current density. The light output power of the full RC-LED device was three times higher than the RC-LED without top TiO2/SiO2 DBR layers under 600 A/cm(2) inject current density. The narrow line width of 7.4 nm, emission peak localization at 410 nm, and three times higher output power were caused by the resonance effect in this vertical cavity structure. (C) 2003 Published by Elsevier B.V.
MOCVD growth of high-performance InGaAsP/InGaP strain-compensated VCSELs with 850 nm emission wavelength
(2004-01-19)
Kuo, HC
;
Chang, YS
;
Lin, CF
;
Lu, TC
;
Wang, SC
We present in this paper the metalorganic chemical vapor deposition growth and characterization of high-performance 850 nm InGaAsP/InGaP strain-compensated MQWs vertical-cavity surface-emitting lasers (VCSELs). The InGaAsP/InGaP MQWs growth condition was optimized using photoluminescence. These VCSELs exhibit superior characteristics, with threshold currents similar to 0.4 mA, and slope efficiencies similar to 0.6 mW/mA. The threshold current change is less than 0.2 mA and the slope efficiency drops by less than similar to 30% when the substrate temperature is raised from room temperature to 85degreesC. These VCSELs also demonstrate high-speed modulation bandwidth up to 12.5 Gbit/s from 25degreesC to 85degreesC. (C) 2003 Elsevier B.V. All rights reserved.
Convergent electron beam induced growth of copper nanostructures: Evidence of the importance of a soft template
(2004-01-20)
Yen, MY
;
Chiu, CW
;
Chen, FR
;
Kai, JJ
;
Lee, CY
In a transmission electron microscope, CuCl particles were irradiated by a convergent electron beam (CEB, 200 kV, 200 pA/cm(2), beam diameter of ca. 1-2 mum) to induce growth of copper nanostructures. Upon CEB irradiation, Cu nanoparticles (5-20 nm in diameter) were formed from commercial CuCl. Using synthesized CuCl encapsulated in permethylpolysilane, growth of polycrystalline copper nanowires (50-200 nm in diameter and up to 30 mum in length) was observed. Evolution of Cu nanoparticles from the synthesized CuCl was observed from the positions with apparent incomplete encapsulation. The effect of polymer encapsulation, acting as a soft template, is shown to be important to influence the nanostructure growth. The observation supports the vapor-solid reaction growth model.
快速分配音訊位元之方法
(2004-01-21)
李俊毅
;
莊孝強
;
方耀諄
;
王俊能
;
蔣迪豪
一種快速分配音訊位元之方法，主要係以整體量化增益(globalgain)以及所使用之位元量(bit)間的線性關係(linearrelationship)建立線性模型，並配合平行化之量化誤差計算而取得音頻編碼所需之位元量，藉以改善傳統包括外部(量化雜訊控制)、內部(碼率控制)雙重回圈耗功費時之運算過程，提升整體的編碼速度，並保持一定水平之音訊品質。
METHOD FOR TRANSFERRING EPITAXY LAYER
(2004-01-22)
YewChung, Wu
;
PeiYan, Lin
A method for transferring an epitaxy layer is provided. The method includes steps of (a) providing a first substrate, (b) forming a first epitaxy layer on the first substrate, (c) forming a masking layer having at least a pattern on the first epitaxy layer, (d) forming a second epitaxy layer on the masking layer, (e) bonding a second substrate to the second epitaxy layer, and (f) removing the masking layer and separating the second epitaxy layer from the first epitaxy layer, thereby the second epitaxy layer being transferred to the second substrate.
Determination of optimal exciter deployment for panel speakers using the genetic algorithm
(2004-01-22)
Bai, MR
;
Liu, BW
;
機械工程學系
;
Department of Mechanical Engineering
A large multi-exciter panel speaker has been constructed in this work. In order to achieve the best design, an optimization procedure using the genetic algorithm (GA) has been developed. A total numerical model was first established for simulation, where the electrical system, the mechanical system, and the acoustical coupling in the panel speaker are accounted for within a coupled framework. Performance indices including the frequency response, the sound power, and the directional response are calculated. The simulation model also serves as the basis for the optimal design that aims at achieving omni-directional responses at high efficiencies. A GA-based optimization scheme was exploited to search for the positions of exciters and the delays of input signals which render the optimal performance. The optimal design was verified by experimental investigations. The results indicate that the optimal configuration indeed produced better performance in terms of efficiency and omni-directionality than the non-optimal one. (C) 2003 Elsevier Science Ltd. All rights reserved.
Intervention of phenonium ion in Ritter reactions
(2004-01-23)
Ho, TL
;
Chein, RJ
;
應用化學系
;
Department of Applied Chemistry
The transformation of phenylethyl chloride to 3,4-dihydroisoquinolines is shown to proceed via phenonium ion. The evidence comes from a study of dideuterated analogue 4, and the monomethylated and dimethylated compounds 2 and 3.
One-polymer active pixel
(2004-01-26)
Tzeng, KL
;
Meng, HF
;
Tzeng, MF
;
Chen, YS
;
Liu, CH
A metal-oxide field-effect transistor (MOSFET) based on an electroluminescent conjugated polymer is fabricated on a glass substrate. It is found that the mobility horizontal to the substrate is two to three orders of magnitude larger than the mobility vertical to the substrate. The high horizontal mobility is attributed to the in-plane chain alignment in amorphous spin-coated films. We demonstrate an active pixel in which the light-emitting diode and the driving MOSFET share the same active polymer. (C) 2004 American Institute of Physics.
A side-chain dendronized nonlinear optical polyimide with large and thermally stable electrooptic activity
(2004-01-27)
Luo, JD
;
Haller, M
;
Li, HX
;
Tang, HZ
;
Jen, AKY
音声信号を送信およびパックするためのデジタル符号化方法およびアーキテクチャ
(2004-01-29)
劉　▲啓▼民
;
李　文傑
【課題】高い品質とより低い計算の複雑さを有する、音声信号の送信およびパックのためのデジタル符号化方法を提供すること。【達成手段】デジタル符号化方法は、入力音声信号を、音声信号のスペクトル構成を表す周波数サンプルのシーケンスに変換し、かつ、これを、マスク閾値を参照することによって量子化パラメータを評価するためのパラメータ予測器を用いるビット割当装置に従い、量子化する。量子化された値は、いくつかのビットからなるデータへと符号化される。繰り返しのレート制御ループが、符号化されるビット数が符号化されるデータに利用可能な指定のビット数を超えると、量子化パラメータおよび量子化ステップサイズを調節する。また、入力音声信号の高周波成分を、繰り返しレート制御ループによって決定されたカットオフ周波数に従って、周波数サンプルのシーケンスを量子化する前にカットオフすることができる。【選択図】　　　図１
Schottky structure in GaAs semiconductor device
(2004-01-29)
Cheng-Shih, Lee
;
Yi, Chang
The present invention provides a Schottky Structure in gallium arsenide (GaAs) semiconductor device, which comprises a gallium arsenide (GaAs) semiconductor substrate, a titanium (Ti) layer on a surface of said gallium arsenide (GaAs) semiconductor substrate to form Schottky contact, a diffusion barrier layer on a surface of said titanium (Ti) layer to block metal diffusion, and a first copper layer on a surface of said diffusion barrier layer.