Browsing by Issue Date, starting with "2002-03-11"

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Electrical and dielectric behavior of MgO doped Ba0.7Sr0.3TiO3 thin films on Al2O3 substrate
(2002-03-11)
Lee, SY
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this letter, we present the results of the fabrication and characterization of 5 mol % MgO doped Ba0.7Sr0.3TiO3 (BST) films grown on Pt/TiN/SiO2 coated on Al2O3 substrates using the rf magnetron sputtering technique. The dielectric and electrical properties of Ba0.7Sr0.3TiO3 thin film were found to improve obviously by means of MgO doping. The leakage current density of BST thin film decreased about 1 order of magnitude on MgO doping, while BST film with MgO doping had a higher dielectric constant than that without MgO doping. The dielectric constant of the films increased with increasing annealing temperature due to the consistent increase in grain size and crystallinity. The 750 degreesC annealed, 100 nm thick film indicated a high dielectric constant of 440 at 100 kHz and the lattice constant of 3.986 Angstrom. The improvement of the electrical properties of BST films was associated with the reduced oxygen vacancies due to improved oxygenation of BST films in the presence of MgO. The MgO doped BST films exhibited a high tunability of 25% and dc resistivity of 6x10(10) Omega cm at an applied electric field of 200 kV/cm. The time-dependent dielectric breakdown studies indicated that the films had a longer lifetime of over 10 yrs on operation at the electric field of 0.4 MV/cm which is better than undoped BST film. (C) 2002 American Institute of Physics.
Field emission from well-aligned carbon nanotips grown in a gated device structure
(2002-03-11)
Tsai, CL
;
Chen, CF
;
Lin, CL
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Vertically well-aligned, high-aspect-ratio carbon nanotips have been directly grown upward on the gated device structure with 4 mum gate aperture. The nanotips rapidly nucleate and grow without any catalyst. In addition, selected area deposition of nanotips is achieved by using a Pt layer as inhibitor in the bias-assisted microwave plasma chemical vapor deposition. The field emission current of nanotips on the gated structure is 154 muA (at a gate-to-cathode voltage of V-gc=50 V). This results from the following reasons: (i) short gate-tips spacing, (ii) small gate aperture, and (iii) the high-aspect ratio of nanotips. (C) 2002 American Institute of Physics.
｢邋遢齋｣名之秘辛
(2002-03-15)
管管
Diode-pumped Q-switched Nd : YVO4 yellow laser with intracavity sum-frequency mixing
(2002-03-15)
Chen, YF
;
Tsai, SW
;
電子物理學系
;
光電工程學系
;
Department of Electrophysics
A compact high-power yellow pulsed laser has been. demonstrated by use of intracavity sum-frequency mixing in a diode-end-pumped Q-switched Nd:YVO4 dual-wavelength laser. A three-mirror configuration forming two separate laser cavities is used to optimize the gain match for simultaneous dual-wavelength emission in Q-switched operation. Under the optimum cavity-length condition, the highest yellow average power is 340 mW and the peak power is 2 kW, obtained at 12.5 W of pump power. (C) 2002 Optical Society of America.
Visual requirement representation
(2002-03-15)
Chen, DJ
;
Chen, WC
;
Kavi, KM
;
資訊工程學系
;
Department of Computer Science
Multimedia technology has played an important role in modern computing because it offers more natural and user-friendly interactions with an automated system. This is particularly true for systems utilizing graphical, icon or window-based input and output. Multimedia technology also facilitates "reuse" more naturally, since the basic components and functions of presentation and animation can be reused for several different animation scenarios. This is evidenced by the rapid prototyping capability of computer and video games where although the characters and story lines change, the basic animation remains constant. In this paper we utilize multimedia technology for eliciting requirements of software systems, particularly those systems that utilize windows- (or graphical)-based interactions with the user. Our methodology will implicitly emphasize reuse since in our approach reusable components include not only code and documents, but also voice narration, animation sequences and message mechanisms. We call such software components as multimedia reusable components (MRCs). Using MRCs. one can view software requirements instead of reading textual representation of the requirements. (C) 2002 Elsevier Science Inc. All rights reserved.
｢邋遢齋｣名之秘辛
(2002-03-15)
管管
Effect of ruthenium doping on the optical and photorefractive properties of Bi12TiO20 single crystals
(2002-03-15)
Marinova, V
;
Hsieh, ML
;
Lin, SH
;
Hsu, KY
;
電子物理學系
Bi12TiO20 (BTO) single crystals nominally pure and doped with ruthenium are grown by top-seeded solution growth method. The effect of ruthenium concentration on optical and photorefractive properties is studied. Strong influence of doping on these properties is observed. It is shown that optical transmission of crystal samples with higher ruthenium content is shifted to the near IR spectral region, while the absorption coefficient is considerably increased. The optical activity of Ru doped crystals is further reduced in comparison with undoped BTO. Photochromic effect is observed in strongly doped crystal. Photorefractive properties are experimentally investigated using two-beam coupling. Response time and diffraction efficiency are changed with ruthenium content. (C) 2002 Elsevier Science B.V. All rights reserved.
｢邋遢齋｣名之秘辛
(2002-03-15)
管管
｢邋遢齋｣名之秘辛
(2002-03-15)
管管
An efficient multiple-path routing protocol for ad hoc networks
(2002-03-15)
Jiang, MH
;
Jan, RH
;
Wang, CF
;
資訊工程學系
;
Department of Computer Science
An ad hoc network is a cooperative engagement of a collection of mobile hosts that requires no intervening of any centralized access point or existing infrastructure, Each mobile host, operating as a specialized router, forwards packets from other mobile hosts. The possibility of fast movement of mobile hosts means network topologies may change frequently. Thus, applying traditional routing schemes to ad hoc networks is inappropriate. In this paper, we present an efficient routing protocol called the multiple next hops (MNH) routing protocol, which is based on the ad hoc on-demand distance vector (AODV) routing protocol for ad hoc networks. The proposed MNH protocol establishes multiple paths for a route discovery procedure, thus conserving network bandwidth and reducing route reconstruction times when routing paths fail. Numerical experiments are given to show the effectiveness of the MNH routing protocol. (C) 2002 Elsevier Science B.V. All rights reserved.
A fuzzy seasonal ARIMA model for forecasting
(2002-03-16)
Tseng, FM
;
Tzeng, GH
;
科技管理研究所
;
Institute of Management of Technology
This paper proposes a fuzzy seasonal ARIMA (FSARIMA) forecasting model, which combines the advantages of the seasonal time series ARIMA (SARIMA) model and the fuzzy regression model. It is used to forecast two seasonal time series data of the total production value of the Taiwan machinery industry and the soft drink time series. The intention of this paper is,to provide business which are affected by diversified management with a new method to conduct short-term forecasting. This model includes both interval models with interval parameters and the possible distribution of future value. Based on the results of practical application, it can be shown that this model makes good forecasts and is realistic. Furthermore, this model makes it possible for decision makers to forecast the best and worst estimates based on fewer observations than the SARIMA model. (C) 2002 Elsevier Science B.V. All rights reserved.
Layered silicates/fluorinated polyimide nanocomposites for advanced dielectric materials applications
(2002-03-18)
Jiang, LY
;
Leu, CM
;
Wei, KH
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Structured silicates/fluorinated polyimide nanocomposites display excellent water-absorption retardation behavior. This leads to lower leakage-current densities and lower dielectric constants under higher humidity conditions than those of the pristine fluorinated polyimides. Part of the chemical structure of the lavered silicate used in this work is shown in the Figure.
CPn model on fuzzy sphere
(2002-03-18)
Chan, CT
;
Chen, CM
;
Lin, FL
;
Yang, HS
;
電子物理學系
We construct the CPn model on fuzzy sphere. The Bogomolny bound is saturated by (anti-)self-dual solitons and the general solutions of BPS equation are constructed. The dimension of moduli space describing the BPS solution on fuzzy sphere is exactly the same as that of the commutative sphere or the (noncommutative) plane. We show that in the soliton backgrounds, the number of zero modes of Dirac operator on fuzzy sphere, Atiyah-Singer index, is exactly given by the topological charge of the background solitons. (C) 2002 Elsevier Science B.V. All rights reserved.
Real index-guided InGaAlP red lasers with buried tunnel junctions
(2002-03-18)
Lu, TC
;
Shieh, HM
;
Wang, SC
;
光電工程學系
;
Department of Photonics
Real index-guided buried ridge InGaAlP 650 nm band lasers with p(+)-n(+) buried tunnel junctions are demonstrated. Located on top of the buried ridges, the tunnel junctions, made of InGaAs/GaAs superlattices with modulation doping, were introduced as the current injection window areas. The large band gap In0.5Al0.5P layers were directly regrown around the ridges using metalorganic chemical vapor deposition to serve as the current blocking layers. Real index optical waveguiding in the lateral direction was also provided by the smaller refractive index of In0.5Al0.5P layers. The lasers showed lower threshold current and higher slope efficiency compared to conventional complex index-guided InGaAlP lasers with GaAs current blocking layers, and had low internal loss of about 5.4 cm(-1). (C) 2002 American Institute of Physics.
Effect of annealing temperature on physical and electrical properties of Bi3.25La0.75Ti3O12 thin films on Al2O3-buffered Si
(2002-03-18)
Sun, CL
;
Chen, SY
;
Chen, SB
;
Chin, A
;
材料科學與工程學系
The effect of annealing temperature, especially at high temperatures, on the physical and electrical properties of Bi3.25La0.75Ti3O12 (BLT) thin films on Al2O3 (10 nm)/Si has been investigated. The width of memory window in capacitance-voltage curves for BLT/Al2O3/Si capacitors annealed at temperature range of 700 degreesC-950 degreesC increases with increasing annealing temperature. At the highest annealing temperature of 950 degreesC, a large ferroelectric memory window of 13 V is obtained under +/-15 V sweep voltage, and this large ferroelectric memory window should be related to the reduced leakage current. Owing to the excellent electrical properties, the high-temperature stable BLT/Al2O3/Si capacitor is compatible with current very large scale integrated technology process. (C) 2002 American Institute of Physics.
Expression, characterization, and purification of recombinant porcine lactoferrin in Pichia pastoris
(2002-03-20)
Mao, SJT
;
Wang, SH
;
生物科技學系
;
Department of Biological Science and Technology
Suppressing tumor progression and inducing cell differentiation on prostate cancer cells by human psychosomatic power
(2002-03-20)
Yu, T
;
Hwang, ML
;
Tsai, WL
;
Sheu, JJC
;
應用化學系
Expression, characterization, and purification of recombinant porcine lactoferrin in Pichia pastoris
(2002-03-20)
Mao, SJT
;
Wang, SH
;
生物科技學系
;
Department of Biological Science and Technology
Exact solution of inventory replenishment policy for a linear trend in demand - two-equation model
(2002-03-21)
Lo, WY
;
Tsai, CH
;
Li, RK
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
This study presents a model for obtaining the exact optimal solution of inventory replenishment policy problem. The proposed model, called the "two-equation model", includes two governing equations and a time-frequency algorithm: the first equation determines the optimal replenishment times for a specified number of replenishments; the second equation determines the optimal number of replenishments. The time-frequency algorithm includes two main procedures to solve the first and second equations. In contrast to many approximation approaches, this model exactly solves the first equation, a simultaneous non-linear equations system using a generalized matrix-based solver. This study also examines the classical no-shortage inventory replenishment policy for linear increasing and decreasing trend demand. According to these results, the solution given by the two-equation model is an exact solution. (C) 2002 Elsevier Science B.V. All rights reserved.
Analyses of beta-lactoglobulin as a thermal marker in raw and commercially processed hulk using a native gel electrophoresis and circular dichroic spectrum
(2002-03-22)
Chen, WL
;
Mao, SJT
;
生物科技學系
;
Department of Biological Science and Technology