Browsing by Issue Date, starting with "2009-11-13"

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A Strain-Driven Morphotropic Phase Boundary in BiFeO3
(2009-11-13)
Zeches, R. J.
;
Rossell, M. D.
;
Zhang, J. X.
;
Hatt, A. J.
;
He, Q.
Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.
A Strain-Driven Morphotropic Phase Boundary in BiFeO(3)
(2009-11-13)
Zeches, R. J.
;
Rossell, M. D.
;
Zhang, J. X.
;
Hatt, A. J.
;
He, Q.
Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO(3)) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.
Glucose sensing by electrochemically grown copper nanobelt electrode
(2009-11-15)
Huang, Ting-Kai
;
Lin, Kuan-Wen
;
Tung, Sze-Ping
;
Cheng, Ta-Ming
;
Chang, I-Chun
A simple design of growing Cu nanobelt (NB) electrode for glucose sensing is presented. Cu NBs were grown directly on carbon electrodes by using electrochemical deposition. The average width, thickness and length of the NBs were about 50 nm, 20 nm and several tens of micrometers, respectively. Cyclic voltammetric (CV) experiments showed that a Cu NB electrode grown by a reduction charge of 0.5 C on a substrate of 0,018 cm(2) enhanced glucose oxidation ability. For glucose sensing, the electrode exhibited a high sensitivity of 79.8 mu A/mM and a measurable detection limit of 10 mu M in amperometric detection. (C) 2009 Elsevier B.V. All rights reserved.
Wavelength-Tunable Laser for Signal Remodulation in WDM Access Networks Using DPSK Downlink and OOK Uplink
(2009-11-15)
Yeh, C. H.
;
Chow, C. W.
;
Shih, F. Y.
;
Wang, C. H.
;
Wu, Y. F.
In this investigation, a simple wavelength-tunable laser based on a Fabry-Perot laser diode (FP-LD) and an erbium-doped fiber amplifier to serve as a downlink signal in a colorless wavelength-division-multiplexed passive optical network (PON) is proposed and experimentally demonstrated. The tuning range of the proposed laser is between 1529.48 and 1560.72 nm, and the output performance of proposed laser is discussed. Colorless operation is implemented by using an FP-LD and a reflective semiconductor optical amplifier in each optical network unit for uplink signal remodulation, respectively. In addition, error-free data signal remodulation using 10-Gb/s downlink differential phase-shift keying and 2.5-Gb/s uplink on-off keying is achieved in a 25-km reach PON.
Supramolecular Assembly of H-Bonded Side-Chain Polymers Containing Conjugated Pyridyl H-Acceptor Pendants and Various Low-Band-Gap H-Donor Dyes Bearing Cyanoacrylic Acid Groups for Organic Solar Cell Applications
(2009-11-15)
Liang, Tzung-Chi
;
Chiang, I-Hung
;
Yang, Po-Jen
;
Kekuda, Dhananjay
;
Chu, Chih-Wei
Novel supramolecular side-chain polymers were constructed by complexation of proton acceptor (H-acceptor) polymers, i.e., side-chain conjugated polymers P1-P2 containing pyridyl pendants, with low-band-gap proton donor (H-donor) dyes S1-S4 (bearing terminal cyanoacrylic acids) in a proper molar ratio. Besides unique mesomorphic properties confirmed by DSC and XPD results, the H-bonds of supramolecular side-chain structures formed by pyridyl H-acceptors and cyanoacrylic acid H-donors were also confirmed by FTIR measurements. H-donor dyes S1-S4 in solid films exhibited broad absorption peaks located in the range of 471-490 nm with optical band-gaps of 1.99-2.14 eV. Furthermore, H-bonded polymer complexes P1/S1-P1/S4 and P2/S1-P2/S4 exhibited broad absorption peaks in the range of 440-462 nm with optical band-gaps of 2.11-2.25 eV. Under 100 mW/cm(2) of AM 1.5 white-light illumination, the bulk heterojunction polymer solar cell (PSC) devices containing an active layer of H-bonded polymer complexes P1/S1-P1/S4 and P2/S1-P2/S4 (as electron donors) mixed with [6,6]-phenyl C(61) butyric acid methyl ester (i.e., PCBM, as an electron acceptor) in the weight ratio of 1:1 were investigated. The PSC device containing H-bonded polymer complex P1/S3 mixed with PCBM (1:1 w/w) gave the best preliminary result with an overall power conversion efficiency (PCE) of 0.50%, a short-circuit current of 3.17 mA/cm(2), an open-circuit voltage of 0.47 V, and a fill factor of 34%. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5998-6013, 2009
Determination of optimal phenanthrene, sulfate and biomass concentrations for anaerobic biodegradation of phenanthrene by sulfate-reducing bacteria and elucidation of metabolic pathway
(2009-11-15)
Tsai, Jen-Chieh
;
Kumar, Mathava
;
Chang, Sue-Min
;
Lin, Jih-Gaw
;
環境工程研究所
Anaerobic biodegradation of phenanthrene (PHE) was investigated using an enrichment culture consists predominantly of sulfate-reducing bacteria (87 +/- 6%). Aqueous biodegradation experiments were designed using the rotatable central composite design with five levels. The designed concentrations were 2-50 mg L(-1) for PHE, 480-3360 mg L(-1) for sulfate, and 5-50 mg L(-1) for initial biomass. Experimental results indicated that the biomass concentration was the most significant variable, followed by the sulfate and PHE concentrations. The desirability functions methodology (DFM) was applied to find out the maximum specific PHE removal rate (R(s)). The maximum R(s) of 9.0 mg g(-1) VSS d(-1) within the designed ranges was obtained when the initial PHE, sulfate and biomass concentrations were 18.5, 841 and 50 mg L(-1), respectively. The R(s) observed in the present study was higher than the values reported in the previous studies. Subsequently, a confirmation study was performed under the optimal conditions. and the results matched well with the R(s) estimated using DFM. Samples collected during PHE biodegradation experiments inferred the formation of two novel metabolic intermediates, 2-methyl-5-hydroxybenzaldehyde and 1-propenyl-benzene, and subsequently degraded to p-cresol, phenol and hydrocarbons. (C) 2009 Elsevier B.V. All rights reserved.
A facile approach to fabricate Ni inverse opals at controlled thickness
(2009-11-15)
Huang, Yi-Jui
;
Lai, Chun-Han
;
Wu, Pu-Wei
;
Chen, Li-Yin
;
材料科學與工程學系
A vertical electrophoretic deposition method was employed to fabricate polystyrene (PS) colloidal crystals with negligible defects and considerable surface uniformity. Subsequently, the interstitial voids within the colloidal crystals were electroplated with Ni, followed by selective removal of the PS microspheres. With careful adjustment in the processing parameters. we were able to obtain Ni inverse opals at predetermined thickness in relatively short time. The inverse opals revealed superb structural stability and surface uniformity. Because the electrophoresis and electrodeposition were both carried out in a solution state, this fabrication scheme enables facile construction of inverse opals on conductive substrates over conventional approaches. (C) 2009 Elsevier B.V. All rights reserved.
Radial groundwater flow to a finite diameter well in a leaky confined aquifer with a finite-thickness skin
(2009-11-15)
Yang, Shaw-Yang
;
Yeh, Hund-Der
;
環境工程研究所
;
Institute of Environmental Engineering
A mathematical model that describes the drawdown due to constant pumpage from a finite radius well in a two-zone leaky confined aquifer system is presented. The aquifer system is overlain by an aquitard and underlain by an impermeable formation. A skin zone of constant thickness exists around the wellbore. A general solution to a two-zone leaky confined aquifer system in Laplace domain is developed and inverted numerically to the time-domain solution using the modified Crump (1976) algorithm. The results show that the drawdown distribution is significantly influenced by the properties and thickness of the skin zone and aquitard. The sensitivity analyses of parameters of the aquifer and aquitard are performed to illustrate their effects on drawdowns in a two-zone leaky confined aquifer system. For the negative-skin case, the drawdown is very sensitive to the relative change in the formation transmissivity. For the positive-skin case, the drawdown is also sensitive to the relative changes in the skin thickness, and both the skin and formation transmissivities over the entire pumping period and the well radius and formation storage coefficient at early pumping time. Copyright (C) 2009 John Wiley & Sons, Ltd.
Generation of multi-octave-spanning laser harmonics by cascaded quasi-phase matching in a monolithic ferroelectric crystal
(2009-11-15)
Hsu, Wei-Chun
;
Lai, Ying-Yao
;
Lai, Chien-Jen
;
Peng, Lung-Han
;
Pan, Ci-Ling
We report the generation of the second to the sixth harmonics of a fundamental frequency covering two and a half octaves in a multiply-periodically poled lithium tantalate crystal by cascaded quasi-phase-matched frequency mixing. A frequency comb that is composed of these harmonics will permit the synthesis of a train of periodic subcycle subfemtosecond pulses in a compact setting. (C) 2009 Optical Society of America
Identification of interrelationship of key customers' needs based on structural model for services/capabilities provided by a Semiconductor-Intellectual-Property Mall
(2009-11-15)
Li, Chung-Wei
;
Tzeng, Gwo-Hshiung
;
科技管理研究所
;
Institute of Management of Technology
The semiconductor industry is shifting towards innovation and acquisition of intellectual property. Semiconductor-Intellectual-Property (SIP) design, a new industry, is also rapidly growing. This challenges both providers and users to develop infrastructure and standard interfaces. Establishing an SIP Mall to provide a full array of SIP business services is a new concept used to promote growth of the SIP industry. Many foundries and governments have been involved in setting up SIP Malls; however, the major services needed for an SIP Mall to attract SIP providers and SIP users must still be clarified. In this paper, the DEMATEL (DEcision MAking Trial and Evaluation Laboratory) method was used to discover and illustrate the key services needed to attract SIP users and SIP providers to an SIP Mall. Research enabled the derivation of the interrelated services and the structural interrelationship between them using the DEMATEL method. Overall, four key services were found to be vital for an SIP Mall to attract customers and to allocate resources efficiently. (C) 2009 Elsevier Inc. All rights reserved.
Magnetism-induced ferroelectric polarization in the c-axis-oriented orthorhombic HoMnO(3) thin films
(2009-11-15)
Lin, T. H.
;
Hsieh, C. C.
;
Luo, C. W.
;
Lin, J. -Y.
;
Sun, C. P.
The magnetism-induced ferroelectricity in the E-type orthorhombic HoMnO(3) (o-HMO) films grown on Nb-doped and undoped SrTiO(3)(001) substrates was studied. The temperature dependent magnetization in these films evidently exhibits an antiferromagnetic ordering around 44 K and an anomalous second magnetic ordering along the c-axis near 35 K. Interestingly, at this anomalous transition temperature, an associated ferroelectric polarization was probed by the P-E hysteresis measurements, indicating the intimated coupling between the ferroelectric response and the reordering of Mn spins, which has never been disclosed previously by dielectric constant measurements. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3260241]
Optimal management of the machine repair problem with working vacation: Newton's method
(2009-11-15)
Wang, Kuo-Hsiung
;
Chen, Wei-Lun
;
Yang, Dong-Yuh
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
This paper studies the M/M/1 machine repair problem with working vacation in which the server works with different repair rates rather than completely terminating the repair during a vacation period. We assume that the server begins the working vacation when the system is empty. The failure times, repair times, and vacation times are all assumed to be exponentially distributed. We use the MAPLE software to compute steady-state probabilities and several system performance measures. A cost model is derived to determine the optimal values of the number of operating machines and two different repair rates simultaneously, and maintain the system availability at a certain level. We use the direct search method and Newton's method for unconstrained optimization to repeatedly find the global minimum value until the system availability constraint is satisfied. Some numerical examples are provided to illustrate Newton's method. (C) 2009 Published by Elsevier B.V.
Magnetism-induced ferroelectric polarization in the c-axis-oriented orthorhombic HoMnO3 thin films
(2009-11-15)
Lin, T. H.
;
Hsieh, C. C.
;
Luo, C. W.
;
Lin, J. -Y.
;
Sun, C. P.
The magnetism-induced ferroelectricity in the E-type orthorhombic HoMnO3 (o-HMO) films grown on Nb-doped and undoped SrTiO3(001) substrates was studied. The temperature dependent magnetization in these films evidently exhibits an antiferromagnetic ordering around 44 K and an anomalous second magnetic ordering along the c-axis near 35 K. Interestingly, at this anomalous transition temperature, an associated ferroelectric polarization was probed by the P-E hysteresis measurements, indicating the intimated coupling between the ferroelectric response and the reordering of Mn spins, which has never been disclosed previously by dielectric constant measurements. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3260241]
形成孔洞性材料之方法
(2009-11-16)
呂志鵬
;
徐國原
;
徐幸鈴
;
陳冠宇
;
洪西宗
本發明係為一種形成孔洞性材料之方法，係將一具有多孔隙之第一基材及一相容該第一基材之犧牲材混合，使該犧牲材可滲入於第一基材之孔隙內，完成第一成品，再將該第一成品混合一第二基材，並將該第一成品與第二基材加熱至犧牲材之汽化溫度上，使該第二基材分子產生變化並因黏滯力增加無法進入第一基材之孔隙，且該等犧牲材受熱產生汽化逸出該第一基材之孔隙，使第二基材無法滲入該第一基材之孔隙並形成第二成品，以保留第一基材之孔隙內之成份。
半導體電路與微探針感測元件的整合結構及其製造方法
(2009-11-16)
邱俊誠
;
張志瑋
一種半導體電路與微探針感測元件的整合結構及其製造方法，係於半導體基板一面製作半導體電路，另一面則直接蝕刻出供生理訊號感測之用的微探針構造，再利用沉積方法於微探針表面依序沉積絕緣層與導電層，最後，再使用導電材料電性連接半導體電路之電性連接墊與導電層，從而在同一片半導體基板兩面完成電路與微探針感測元件之整合，且解決了電性阻絕的問題，微探針所感測到的生理訊號準位將不會影響到半導體電路的正常工作。
應用於時脈資料回復電路的多重交替式轉態取樣方法及裝置
(2009-11-16)
林志憲
;
周世傑
;
鄭元樸
;
黃彥穎
;
李舒蓉
一種應用於時脈資料回復電路的多重交替式轉態取樣方法及裝置，其於輸入信號的轉態中心的領先側及落後側多點交替式取樣而得到線性相位增益係數，因而具有交替式取樣的快速鎖定以及線性相位增益係數之優點。
利用自動對準低溫淺接面製造具有極低臨界電壓金屬閘極／高介電常數材質之互補金氧半場效電晶體之方法
(2009-11-16)
荊鳳德
本發明提出一種利用新穎的自動對準低溫超淺接面製造具有極低臨界電壓（Vt）金屬閘極／高介電常數（κ）材質之互補金氧半場效電晶體(CMOSFETs)之方法，其中該方法係採用與超大型積體電路（VLSI）相容之前閘極製程。當等效氧化層厚度（EOT）為1.2奈米時，p型及n型金氧半導體（MOS）分別測得5.3及4.1eV之良好有效功函數、+0.05及0.03V之低臨界電壓、90及243cm 2 /Vs之高遷移率以及在85℃下小於32mV之低偏壓溫度不穩定性(10MV/cm，1hr)。
發光二極體結構及其製造方法
(2009-11-16)
張俊彥
;
楊宗熺
本發明係提供一種發光二極體（LED）結構，該發光二極體係包含一四族半導體構成之基板，一AlN成核層，形成於該四族基板上，一GaN磊晶層，形成於該AlN成核層上，一分散式布拉格反射鏡（DBR）多層結構，形成於該圖型化之GaN磊晶層上，以及一LED作用層結構，形成於該DBR多層結構上。
具有磁性單晶薄膜的單晶磁性奈米膠囊藥物載體
(2009-11-16)
陳三元
;
胡尚秀
;
劉典謨
本發明揭示一種具有磁性單晶薄膜的單晶磁性奈米膠囊藥物載體，所形成的奈米尺度的單晶氧化鐵殼層內可包含藥物或生物分子，運用磁性奈米單晶膠囊結構藥物載體具有良好的磁敏感特性，當使用磁場操控時，可以迅速精準的釋放適量藥物,也可使藥物達到完全零釋放,故可運用於藥物輸送系統。
無石英震盪器之通訊收發裝置與可自我校正嵌入式虛擬晶體震盪器時脈輸出之方法
(2009-11-16)
李鎮宜新竹市大學路1001號國立交通大學電子工程學系
;
游瑞元
一種無石英震盪器之通訊收發裝置與可自我校正嵌入式虛擬晶體震盪器時脈輸出之方法，其是由通信系統之收發兩端的其中一通訊收發裝置提供另一通訊收發裝置一參考訊號，則該通訊收發裝置可以根據此參考訊號產生一對應的參考頻率。