Browsing by Author "Lin, YJ"

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A novel large displacement electrostatic actuator: pre-stress comb-drive actuator
(2005-09-01)
Chiou, JC
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Lin, YJ
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電控工程研究所
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Institute of Electrical and Control Engineering
This investigation proposes a novel large vertical displacement electrostatic actuator, called the pre-stress comb-drive actuator (PCA), which exhibits no pull-in and no hysteresis characteristics. The proposed PCA consists of a set of comb fingers fabricated along the composite beam and substrate. One end of the composite beam is clamped to the anchor, whereas the other end is elevated vertically by the residual stress. The actuation occurs when the electrostatic force, induced by the fringe effect, pulls the composite beam downward to the substrate. A post-heat treatment process was employed to increase the initial lift height of the PCA to obtain a large actuation stroke. A mathematical model, based on a newly developed modeling approach, is introduced to estimate the static characteristic of the PCA. A PCA was fabricated using the PolyMUMPs process based on the proposed design concept. Following packaging and applying a post-heat treatment process, a 110 mu m initial tip height and a 90 mu m vertical motion range were achieved. Neither pull-in nor hysteresis was observed. The simulation results were closely matched with the observations. This work also studies the frequency response and measurement of the maximum vibration of the PCA.
Analysis and DSP implementation of a broadband duct ANC system using spatially feedforward structure
(2001-04-01)
Bai, MR
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Lin, YJ
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機械工程學系
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Department of Mechanical Engineering
The active control technique for broadband attenuation of noise in ducts, using spatially feedfoward structure. is investigated from the viewpoints of both acoustic analysis and exists an ideal controller for this problem. The ideal controller is a function of the finite control engineering. According to the previous work by Munjal and Eriksson [1], there source impedance and is thus independent of the boundary conditions. Despite the simplicity the ideal controller cannot be practically implemented due to the difficulty of calibration of electro-mechanical parameters. To overcome the problem, the controller is implemented via an equivalent formulation modified from the controller originally proposed by Roure [2]. The modified controller is implemented on a DSP platform, using a FIR filter, an IIR filter and a hybrid filter. The experimental results showed that the system achieved 17.2 dB maximal attenuation in the frequency band 300 similar to 600 Hz. Physical insights and design considerations in implementation phase are also discussed in the paper.
Characterization of polysilicon thin-film transistors with asymmetric source/drain implantation
(2005-08-01)
Shieh, MS
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Lin, YJ
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Yu, CM
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Lei, TF
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電子工程學系及電子研究所
The effect of asymmetry tilt angle ion implantation on polysilicon thin-film transistors (TFTs) device characteristics are investigated. This asymmetric source/drain (S/D) TFTs structure exhibits low leakage current and suppressed kink effect due to the relief of higher electric field near the drain junction side. It is shown that the optimal implantation tilt angle is 30 degrees in our annealing condition. And the anomalous off-state current is more than two orders of magnitude lower than that of the conventional TFTs. By well controlled the LDD region, this structure can act as a conventional structure in the on-state and the turn-on current will not be degraded. Besides, the device under severe hot carrier bias stress shows better hot carrier endurance. (c) 2005 Elsevier B.V. All rights reserved.
Convenient synthesis of tavacpallescensin and occidol.
(1997-04-13)
Ho, TL
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Lin, YJ
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應用化學系
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Department of Applied Chemistry
Deployment of personalized e-catalogues: An agent-based framework integrated with XML metadata and user models
(2001-07-01)
Liu, DR
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Lin, YJ
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Chen, CM
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Huang, YW
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資訊管理與財務金融系註：原資管所+財金所
In e-commerce applications, supporting electronic catalogues (e-catalogues) to provide product-search services on the Internet is emerging as an important function of electronic brokers ( e-brokers). However, as the Internet expands, an increasing number of virtual stores are selling products on-line. The explosive growth of information is creating difficulties for customers searching for the product information they desire. In this work, an integrated framework is proposed to develop personalized e-catalogues. The proposed framework integrates XML-based metadata models, user models and agents. The XML-based metadata model can facilitate resource-discovery and format translation, and can flexibly model the definitions of diverse product attributes in heterogeneous data resources. The proposed user model can model a user's shopping interests to resources, categories and products. This work integrates the agent technology with the proposed metadata model and user model to develop a personalized e-catalogue system. The novel system effectively provides an integrated search for heterogeneous product information, as well as supporting personalized product search and browsing for each user based upon their profiles. (C) 2001 Academic Press.
Effect of CuO-based oxide additives on Bi2O3-ZnO-Nb2O5 microwave ceramics
(2001-05-01)
Chen, SY
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Lin, YJ
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材料科學與工程學系
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Department of Materials Science and Engineering
Different kinds of CuO-MO, mixtures were used to investigate their role in the microstructure evolution, sintering densification and microwave properties of Bi-2(Zn1/3Nb2/3)(2)O-7 (BZN) ceramics. Without the addition of CuO-MO, mixtures, pure BZN ceramics have to be sintered above 900 degreesC. However, a comparable bulk density to that of pure BZN ceramics sintered at 950 degreesC can be achieved for 2 wt% 0.29BaCO(3)-0.71 CuO-added at 850 degreesC and 0.15CuO-0,85MoO(3)-added BZN ceramics at 800 degreesC, which was attributed to the liquid-phase sintering. A higher dielectric constant along with a smaller Q factor was obtained in 0.29BaCO(3)-0.71CuO-added BZN ceramics because of the formation of the BaBi2Nb2O9 phase. On the other hand, a larger Q factor of similar to 1500 can be obtained at about 850 degreesC for 1 wt% 0.15CuO-0.85MoO(3)-added BZN ceramics. However, as the 0.2CuO-0.8GCO(2) mixture was used, a partial transformation of pseudo-tetragonal Bi-2(Zn1/3Nb2/3)(2)O-7 to cubic (Bi1.5Zn0.5)(Zn0.5Nb1.5)O-7 phase was induced possibly because both Zn2+ and Ge4+ have similar ion radius and electronegativity. With increasing 0.2CuO-0.8GeO(2) content, a decrease in microwave properties was also obtained due to an inhibition of sintering densification since a eutectic liquid phase was not formed.
Fuzzy logic control of aggregate production planning using genetic algorithms
(1999-12-01)
Hsu, HM
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Lin, YJ
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工業工程與管理學系
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Department of Industrial Engineering and Management
In general, a successful application of fuzzy logic control depends on fuzzy rules, the structure of the rules, and membership functions. This research presents a fuzzy logic control (FLC) model for aggregation production planning by using a genetic algorithm (GA) to simultaneously search the membership functions and inference rule set. It is shown that the genetic algorithm enables us to generate an optimal combination of the membership functions and the rule set. The approach presented in this research is illustrated by using Holt's paint factory data. The comparison of our results with those of Rink and Turksen shows that the proposed approach is the more favorable one. Significance: This research presents a fuzzy logic control (FLC) model for aggregation production planning by using a genetic algorithm (GA) to simultaneously search the membership functions and inference rule set.
Modeling and verification of the double frequency effect using a MEMS device
(2006-07-01)
Chiou, JC
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Lin, YJ
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電控工程研究所
;
Institute of Electrical and Control Engineering
The derivation, verification, and implication of the nonlinear dynamic and frequency response of electrostatic actuator due to the double frequency effect (DFE) were reported in this study. In particular, an extra mode called half mode was observed and measured in various studies. However, a complete in-depth discussion of the effect was not reported in the past. In the present study, a second-order dynamical equation was adapted firstly to model the dynamic and frequency response of electrostatic actuator where typical harmonic input signal with a dc bias was used. Secondly, by solving the equation, complex waveform in dynamic response and an extra half mode in frequency response due to the double frequency effect can be observed and discussed. To verify the simulated result, an electrostatic driving device was fabricated using PolyMUMPS(C) process. Note that in frequency response, when dc bias is equal to the amplitude of ac signal, simulated and experimental results indicated that the amplitude of half mode was one-fourth of first mode.
Phase transformation, reaction kinetics and microwave characteristics of Bi2O3-ZnO-Nb2O5 ceramics
(2003-05-01)
Chen, SY
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Lee, SY
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Lin, YJ
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材料科學與工程學系
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Department of Materials Science and Engineering
Oxide powders of Bi2O3, ZnO and Nb2O5 were used to investigate the phase transformation, reaction kinetics and microwave properties of both Bi-2(Zn1/3Nb2/3)(2)O-7 and (Bi1.5Zn0.5)(Zn0.5Nb1.5)O-7 phases in the Bi2O3-ZnO-Nb2O5 system. Kinetic studies indicate that the formation mechanism of Bi-2(Zn1/3Nb2/3)(2)O-7 phase belongs to diffusion controlled reaction with a zero nucleation rate. In contrast, (Bi1.5Zn0.5)(Zn0.5Nb1.5)O-7 phase was interpreted as diffusion controlled reaction with a constant nucleation rate with either Bi5Nb3O15 or BiNbO4 phases as the nuclei. Furthermore, a lower activation energy and formation temperature were observed in the (Bi1.5Zn0.5)(Zn0.5Nb1.5)O-7 than Bi-2(Zn1/3Nb2/3)(2)O-7 phase. Additionally, the (Bi1.5Zn0.5)(Zn0.5Nb1.5)O-7 phase exhibits a higher dielectric constant but a lower Q value as compared with Bi-2(Zn1/3Nb2/3)(2)O-7 phase. (C) 2002 Elsevier Science Ltd. All rights reserved.
Synthesis and properties of 3-thia-9-azabicyclo[3.3.1]nonan-7-one
(1997-06-01)
Ho, TL
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Lin, YJ
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交大名義發表
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應用化學系
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National Chiao Tung University
N-Benzyl-3-thia-9-aza-bicyclo [3.3.1]nonan-7-one has been prepared from methyl 4-bromocrotonate by reaction sequence involving sodium sulfide, benzylamine, and Dieckmann condensation. Some spectral and chemical properties of this system are also reported.
Synthesis of tavacpallescensin
(1996-06-01)
Ho, TL
;
Lin, YJ
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交大名義發表
;
應用化學系
;
National Chiao Tung University
A five-step synthesis of the marine sponge metabolite tavacpallescensin 7 is reported.
Synthesis of tavacpallescensin and occidol via a common intermediate
(1999-05-07)
Ho, TL
;
Lin, YJ
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應用化學系
;
Department of Applied Chemistry
The symmetrical benzosuberone 3 has been used in the synthesis of tavacpallescensin by an Emmons-Wadsworth condensation, selenium dioxide oxidation and diisobutylaluminium hydride reduction. For the elaboration of occidol, alpha-diazotization, Wolff rearrangement and reaction with methyllithium were involved.
The design and assembly of surface-micromachined optical switch for optical add/drop multiplexer application
(2003-08-01)
Lin, YC
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Chiou, JC
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Lin, WT
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Lin, YJ
;
Wu, SD
An assembly process including: flip-chip bonding, microelectromechanical (MEMS) structure release, and atomic layer deposition (ALD) is proposed to integrate a surface micro-machined optical switch for optical add/drop multiplexer (OADM) applications. In the current optical switch designs, pre-stressed beams were used to pop up the micromirror and an electrode (substrate) under the beams was designed to perform ON/OFF function of the optical switch. In order to achieve desired popped-up angle for precise-optical switching, a flip-chip bonding technique is applied to a mechanical stopper with an accurate joint height that can be used to constrain the movement of the micromirror. A conformal thin layer of dielectric material (Al2O3) coated on the surfaces of device through an ALD coating process is used to improve vertical actuation force, as well as electrical isolation. Experiments indicate that the micromirrors fabricated by the present assembly process can achieve desired angle that meet the requirements of the proposed OADM configuration.