Browsing by Issue Date, starting with "2005-04-20"

Now showing 1 - 20 of 66843

Tenth-order rational-harmonic frequency multiplication and detuning of optical pulse injection-locked erbium-doped fiber laser
(2005-04-20)
Lin, GR
;
Wu, JR
;
光電工程學系
;
Department of Photonics
The jitter and frequency-detuning dynamics of a 10-GHz rational-harmonic frequency-multiplied pulse train generated from an erbium-doped fiber laser (EDFL) is studied. The EDFL is self-feedback seeded and optically injection locked by a gain-switched laser diode (GSLD) with a pulse width and an average power of 1.7.6 ps and 0.2 mW, respectively, at a repetition frequency of 1 GHz. The repetition frequency of the optical pulse train can be tenth-order multiplied by a slight detuning of the repetition frequency of the GSLD to match the rational-harmonic injection-locked condition of the EDFL. As the repetition frequency is multiplied from 1 to 10 GHz, the peak power, the pulse width, and the frequency-detuning bandwidth of the injection-locked EDFL pulses decrease from 1.2 to 0.3 W, from 40 to 21 ps, and from 40 to 9 kHz, respectively. The timing jitter of the injection-locked EDFL repeated at 1 GHz remains unchanged (< 0.5 ps) within the detuning bandwidth, which inevitably increases to 1.2 ps after tenth-order multiplication. (c) 2005 Optical Society of America.
A 0.18-mu m CMOS CMFB downconversion micromixer with deep N-well technology for LO-RF and LO-IF isolation improvements
(2005-04-20)
Meng, CC
;
Hsu, SK
;
Wu, TH
;
Huang, GW
;
電信工程研究所
CMOS deep N-well technology can eliminate the physical effects of NMOS transistors and reduce substrate noise and coupling in order to reach the NMOS channel. These properties result in better LO-IF and LO-RF isolations in a Gilbert micromixer. Two identical 0.18-mu m CMOS downconversion micromixers (except at the RF input stage) with deep N-well or without deep N-well are fabricated in adjacent areas of the same wafer for the purpose of isolation comparison. A -37-dB LO-IF and -38-dB LO-RF isolation downconversion micromixer with 19-dB conversion gain and IP1dB = -20 dBm and IIP3 = -13 dBm when RF = 2.4 GHz and LO = 2.25 GHz is demonstrated here using 0.18-mu m-deep N-well CMOS technology. On the other hand, a downconversion micromixer without deep N-well has almost identical power performance but achieves only -20-dB LO-IF isolation and -21-dB LO-RF isolation. (c) 2005 Wiley Periodicals, Inc.
用於音訊編碼之快速位元分配法
(2005-04-21)
楊政翰
;
杭學鳴
一種用於音訊編碼之快速位元分配法，係在使用虛擬霍夫曼編碼書模型的條件下，先行利用籬柵圖方法對比例因子參數作最佳化，得到一組最佳的比例因子參數。之後，再使用前述獲得之最佳的比例因子參數，利用籬柵圖方法對霍夫曼編碼書參數作最佳化，得到一組最佳的霍夫曼編碼書參數。因此，可在維持近似於習知方法之壓縮效能的情況下，大幅降低位元分配所需之運算量，以利於實際應用之執行。
使用週期性結構的矩形波導及其設計方法
(2005-04-21)
莊晴光
;
吳憲順
本發明係將傳統矩形波導之部份或全部的表面以週期性結構取代。不需要在波導內使用高介電常數之材料，也不需改變矩形波導的操作模態。僅利用週期性結構在低於能階止帶頻段下之擾動特性設計出相較於同尺寸之傳統矩形波導更低截止頻率之矩形波導；另一方面，利用週期性結構在能階止帶頻段中之高阻抗表面特性，實現出以TM10為主模之矩形波導。本發明亦有關於使用週期性結構的矩形波導的設計方法。
不鏽鋼電弧銲用助銲劑
(2005-04-21)
黃和悅
;
徐享文
;
曾光宏
;
楊宗杰
;
周長彬
本發明係提供一種不鏽鋼電弧銲用助銲劑，主要利用氧化錳為底質，並選自由下列各物所組成之群：氧化鋅、氧化矽、氧化鉻、氧化鈦、氧化鉬及氧化鐵等其中至少一者來作為活化添加物與該底質混合而成，用以加深不鏽鋼構件使用電弧銲之熔銲深度，而且改善其銲道之外觀品質。
Method of fabricating copper metallization on backside of gallium arsenide devices
(2005-04-21)
Chang, Edward Yi
;
Lee, Cheng-Shih
A bi-level structure based on copper metallization technique has been applied to backside of gallium arsenide (GaAs) devices. The foundation where the structure stands on is device substrate backside, on which a layer of diffusion barrier is deposited first, and to the top of it, a layer of copper metallization is plated to enhance device performance. The barrier layer can be selected from tungsten (W), tungsten nitride (WN), or titanium tungsten nitride (TiWN) by sputtering or evaporating, which effectively prevents copper from diffusing into GaAs substrate. The layer of copper metallization, formed by employing anyone of sputtering, evaporating, or electroplating, proves to offer attractive thermal and electrical conductivity and mechanical strength and the like. Moreover, these characteristic improvements coupled with a fascinating part, low cost, would benefit and motivate global GaAs fabs.
Anti-HCV activities of selective polyunsaturated fatty acids (vol 318, pg 275, 2004)
(2005-04-22)
Leu, GZ
;
Lin, TY
;
Hsu, JTA
;
生物科技學系
;
Department of Biological Science and Technology
New soluble poly(2,3-diphenylphenylene vinylene) derivatives for light-emitting diodes
(2005-04-22)
Yang, SH
;
Chen, JT
;
Li, AK
;
Huang, CH
;
Chen, KB
Soluble poly(2,3-diphenylphenylene vinylene) (DP-PPV) derivatives, poly(2,3-diphenyl-5-(4-heptyloxy-4'-oxytrimethylenediphenyl)phenylene vinylene) (P1), poly(2,3-diphenyl-5-[4-(4-pentylcyclohexyl)phenoxyl-propyl-p-phenylene vinylene) (P2) and poly(2,3-diphenyl-5-(2-(1, 4, 5-triphenyl-1H-2-imidazoloyl)-1-oxytrimethylene phenyl) phenylene vinylene) (P3), were synthesized. P1 and P2 contain liquid crystal side groups; while P3 contains a charge transport group. The polymers showed solid state UV-Visible absorption and photoluminescence in the range of 370-380 and 480-510 nm, corresponding to blue green emission. Similar to many other reported systems, the solution fluorescence spectra of P1 and P2 showed slight solvent dependency and blue-shifted with respect to those of the films. These were not the case for P3 which showed little solvent dependency and little blue shift in solution. Two-layer light-emitting devices with a simple ITO/PEDOT/polymer/Ca (Al) configuration were fabricated and characterized. (c) 2004 Elsevier B.V. All rights reserved.
Anticontrol and synchronization of chaos for an autonomous rotational machine system with a hexagonal centrifugal governor
(2005-04-22)
Ge, ZM
;
Lee, CI
;
機械工程學系
;
Department of Mechanical Engineering
Anticontrol and synchronization of chaos for an autonomous rotational machine system with a hexagonal centrifugal governor are studied in the paper. Two different procedures for the design of the controller are proposed to anticontrol the governor system effectively. Finally, five methods are studied for chaos synchronization. (c) 2004 Elsevier Ltd. All rights reserved.
Polypeptide-shelled poly(propylene imine) dendrimers and their complexing properties towards copper(II) ions
(2005-04-22)
Appelhans, D
;
Komber, H
;
Kirchner, R
;
Seidel, J
;
Huang, CF
Polypeptide-shelled poly(propylene imine) dendrimers were realized by ring-opening polymerization of alpha-amino acid N-carboxyanhydrides, initiated by dendrimers as core molecules. Polypeptides with 2nd generation core were used as model compounds to investigate interior complexes between metal ion and surface-modified dendrimers. Microcalorimetric measurements outlined the formation of approximate 1:1 complexes between Cu-II and polypeptide-shelled dendrimers and the influence of polypeptide chain compositions on differential molar heats of complexation.
Dry sliding wear behaviors of Al-25Si-2.5Cu-1Mg alloys prepared by powder thixocasting
(2005-04-25)
Chen, CM
;
Yang, CC
;
Chao, CG
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The wear performance of an Al-25Si-2.5Cu-1Mg alloy prepared by powder thixocasting was studied using a pin-on-disc machine. LM13 and an Al-25Si-2.5Cu-lMg alloy prepared by conventional ingot metallurgy were also investigated for comparison. The sliding tests were performed under ambient conditions and without lubricant. During the tests, the applied load was increased stepwise until wear seizure occurred. Experimental data reveal that the powder thixocast alloys exhibit better wear performance than that of conventional alloys, especially under heavy load conditions and following T6 treatment. This work demonstrates the potential of the new method, powder thixocasting, for fabricating hypereutectic Al-Si-X alloys with a high wear resistance. Moreover, the variation in the wear rate with the applied load for the alloy can be divided into three regions. The mechanisms associated with these wear regions were discussed based on the investigations of the worn subsurface and the wear debris. (c) 2005 Elsevier B.V. All rights reserved.
Transient analysis of reactant gas transport and performance of PEM fuel cells
(2005-04-27)
Yan, WM
;
Soong, CY
;
Chen, FL
;
Chu, HS
;
機械工程學系
The dynamic performance of PEM fuel cells is one of the most important criteria in the design of fuel cells with application to mobile systems. To study this issue, we extend our previous steady model of gas reactant transport to an unsteady one and employ it to examine the transient transport characteristics and the system performance of the PEM fuel cells. With the assumption of the two-dimensional mass transport in the cathode side of PEMFC, the effects of the channel width fraction, lambda = l(c)/l(b), the porosity of the gas diffuser layer, epsilon(1), and the surface overpotential of the catalyst layer, eta, on the transient characteristics of the resultant current density and mass transport are focused in this work. It is disclosed that an increase in lambda, or eta may lead to a faster dynamic response for the fuel cell when the PEM fuel cell system is started up. Results of a typical case demonstrate that, although the dynamic response time may be as long as 10 s due to the mass transport lag, the fuel cell system needs only less than 0.4 s to reach the 90% response. (c) 2005 Elsevier B.V. All rights reserved.
Burglarproof security system
(2005-04-28)
Wu, Bing-Fei
;
Chen, Chao-Jung
;
Peng, Hsin-Yuan
A burglarproof security system is disclosed, wherein a video for a target object is recorded and transmitted to a mobile device at the far end at the first time via a wireless communication. The mobile device has a display device for displaying the video, so that a user can monitor and assure the safety of the target object.
二次元アレイ導波管構造
(2005-04-28)
荘晴光
;
陳志強
【課題】マイクロ波集積回路の小型化を達成できる二次元アレイ導波管構造を提供する。【解決手段】本発明の二次元アレイ導波管構造は、第一金属層、第二金属層と誘電体層（dielectric layer）を有する。誘電体層は、第一金属層と前記第二金属層の間に位置し、第一金属層と前記第二金属層を隔てる。第一金属層及び第二金属層は、それぞれ複数の第一ユニットセル及び複数の第二ユニットセルによって、ローとコラム方向に沿って二次元アレイ導波管構造を形成する。各第一ユニットセルは、主体と複数の接続アームによって構成され、各第二ユニットセルは、金属線ループによって構成される。第二金属層は第一金属層の下方に位置し、且つ、各第二ユニットセルはそれぞれ一対一の方式で各第一ユニットセルに対応し、完全なユニットセルを形成する。【選択図】図１ａ
Characterization and conductive coating of phosphors for improved brightness
(2005-04-30)
Chang, CH
;
Chiou, BS
;
Chen, KS
;
Ho, JC
;
電子工程學系及電子研究所
In this study, the phosphors used in CRTs are coated with In2O3 conductive layer derived from the hydrolysis of indium chloride. The conductive coating retards/eliminates charging-up on the phosphor surface during the bombardment of the electrons and improves the cathodoluminescent brightness of the phosphor. However, the non-emissive conductive coating also degrades the cathodoluminescent brightness when it is too thick. The cathodoluminescent brightness increases initially with the amount of coating, reaches a maximum at 10 wt.% InCl3, and decreases with further increase of coating. It is found that with a 10 wt.% InCl3 coating, the brightness of phosphor increases by 20% at 500 V and 1 mu A. (c) 2004 Published by Elsevier B.V.
Hybrid S- to L-band fiber amplifier module with coupled structure
(2005-05-01)
Yeh, CH
;
Chi, S
;
光電工程學系
;
Department of Photonics
Reoxidation behavior of high-nitrogen oxynitride films after O-2 and N2O treatment
(2005-05-01)
Lin, BC
;
Chang, KM
;
Lai, CH
;
Hsieh, KY
;
Yao, JM
Reoxidation of a high-nitrogen ultrathin oxynitride (similar to 1.3nm) has been studied. The reoxidation is conducted using an alternation of nitrous oxide and oxygen gas in rapid thermal oxidation (RTO). The new finding in this study is the zig-zag characteristic of the oxidation rate by O-2 and N2O. It is clear that the N2O oxidation rate is almost independent of the concentration of nitrogen in oxynitride through out the rapid thermal oxidation process, but the O2 oxidation rate is not.
Influence of dislocation density on photoluminescence intensity of GaN
(2005-05-01)
Falth, JF
;
Gurusinghe, MN
;
Liu, XY
;
Andersson, TG
;
Ivanov, IG
The influence of dislocation density on photoluminescence intensity is investigated experimentally and compared to a model. GaN samples were grown by molecular beam epitaxy and metal-organic chemical vapour deposition. Different growth parameters and thicknesses of the layers resulted in different dislocation densities. The threading dislocation density, measured by atomic force microscopy, scanning electron microscopy and X-ray diffraction, covered a range from 5 x 10(8) to 3 x 10(10) cm(-2). Carrier concentration was measured by capacitance-voltage-, and Hall effect measurements and photoluminescence at 2 K was recorded. A model which accounts for the photoluminescence intensity as a function of dislocation density and carrier concentration in GaN is developed. The model shows good agreement with experimental results for typical GaN dislocation densities, 5 x 10(8)-1 x 10(10) cm(-2), and carrier concentrations 4 x 10(16)-1 x 10(18) cm(-3). © 2005 Elsevier B.V. All rights reserved.
Switchable dual-wavelength NRZ-to-RZ data-format transformer using non-DC-biased and synchronously modulated laser diode
(2005-05-01)
Chang, YC
;
Lin, YH
;
Liao, YS
;
Lin, GR
;
光電工程學系
The switchable dual-wavelength and wavelength-converted nonretum-to-zero-to-return-to-zero (NRZ-to-RZ) data transformation is demonstrated by externally seeding a synchronously sinusoidal-modulated laser diode with an optical pseudorandom bit sequence data at 1 Gbps. A maximum wavelength tuning range of 30 nm with an SMSR of greater than 36 dB is obtained. 1 Gbps on/off keying of single-mode RZ data pulse-train generated by externally seeding synchronously sinusoidal-modulated laser diode is demonstrated.
The molecular mechanism of actinomycin D in preventing neointimal formation in rat carotid arteries after balloon injury
(2005-05-01)
Wu, CH
;
Pan, JS
;
Chang, WC
;
Hung, JS
;
Mao, SJT
The pathological mechanism of restenosis is primarily attributed to excessive proliferation of vascular smooth muscle cells (SMC). Actinomycin D has been regarded as a potential candidate to prevent balloon injury-induced neointimal formation. To explore its molecular mechanism in regulating cell proliferation, we first showed that actinomycin D markedly reduced the SMC proliferation via the inhibition of BrdU incorporation at 80 nM. This was further supported by the G1-phase arrest using a flowcytometric analysis. Actinomycin D was extremely potent with an inhibitory concentration IC50 at 0.4 nM, whereas the lethal dose LD50 was at 260 mu M. In an in vivo study, the pluronic gel containing 80 nM and 80 lMactinomycin D was applied topically to surround the rat carotid adventitia; the thickness of neointima was substantially reduced (45 and 55%, respectively). The protein expression levels of proliferating cell nuclear antigen ( PCNA), focal adhesion kinase (FAK), and Raf were all suppressed by actinomycin D. Extracellular signal-regulated kinases (Erk) involved in cell-cycle arrest were found to increase by actinomycin D. These observations provide a detailed mechanism of actinomycin D in preventing cell proliferation thus as a potential intervention for restenosis.