Browsing by Issue Date, starting with "1996-11-21"

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Reduction of semiconductor laser amplifier induced distortion and crosstalk for WDM systems using light injection
(1996-11-21)
Ho, KP
;
Liaw, SK
;
Lin, CL
;
光電工程研究所
;
Institute of EO Enginerring
Semiconductor laser amplifiers muse both distortion and crosstalk in WDM systems due to gain saturation. A method using Light injection is experimentally demonstrated to reduce distortion and crosstalk, In a two-channel experiment with a data rate of 2.5 Gbit/s, it is found that light injection can eliminate the BER floor due to distortion and crosstalk.
Reduction of semiconductor laser amplifier induced distortion and crosstalk for WDM systems using light injection
(1996-11-21)
Ho, KP
;
Liaw, SK
;
Lin, CL
;
光電工程學系
;
Department of Photonics
Semiconductor laser amplifiers muse both distortion and crosstalk in WDM systems due to gain saturation. A method using Light injection is experimentally demonstrated to reduce distortion and crosstalk, In a two-channel experiment with a data rate of 2.5 Gbit/s, it is found that light injection can eliminate the BER floor due to distortion and crosstalk.
A modified H-2 feedforward active control system for suppressing broadband random and transient noises
(1996-11-21)
Bai, M
;
Chen, H
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
Three feedforward active noise control algorithms based on H-2, H-infinity, and modified H-2 optimal model matching principles are investigated in this study. The first two methods provide significant attenuation for broadband random noises. However, the H-2 and H-infinity methods generally result in high-gain controllers at high frequencies, which calls for some truncation measures in the frequency domain. The third method effectively eliminates the high-gain problem of the ordinary H-2 and H-infinity algorithms. In addition, this method is guaranteed to result in a causal and stable controller which is crucial in practical implementation. The algorithms are coded into controllers by using a floating-point digital signal processor. The experimental results show significant attenuation for stationary broadband random noises as well as transient impact noises in a duct. (C) 1996 Academic Press Limited
A modified H-2 feedforward active control system for suppressing broadband random and transient noises
(1996-11-21)
Bai, M
;
Chen, H
;
機械工程學系
;
Department of Mechanical Engineering
Three feedforward active noise control algorithms based on H-2, H-infinity, and modified H-2 optimal model matching principles are investigated in this study. The first two methods provide significant attenuation for broadband random noises. However, the H-2 and H-infinity methods generally result in high-gain controllers at high frequencies, which calls for some truncation measures in the frequency domain. The third method effectively eliminates the high-gain problem of the ordinary H-2 and H-infinity algorithms. In addition, this method is guaranteed to result in a causal and stable controller which is crucial in practical implementation. The algorithms are coded into controllers by using a floating-point digital signal processor. The experimental results show significant attenuation for stationary broadband random noises as well as transient impact noises in a duct. (C) 1996 Academic Press Limited
Fuzzy bicriteria multi-index transportation problems for coal allocation planning of Taipower
(1996-11-22)
Tzeng, GH
;
Teodorovic, D
;
Hwang, MJ
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
Taipower, the official electricity authority of Taiwan, encounters several difficulties in planning annual coal purchase and allocation schedule, e.g., with multiple sources, multiple destinations, multiple coal types, different shipping vessels, and even in uncertain demand and supply. In this study, these concerns are formulated as a fuzzy bicriteria multi-index transportation problem. Furthermore, an effective and interactive algorithm is proposed which combines reducing index method and interactive fuzzy multi-objective linear programming technique to cope with a complicated problem which may be prevalent in other industries. Results obtained in this study clearly demonstrate that this model can not only satisfy more of the actual requirements of the integral system but also offer more information to the decision makers (DMs) for reference in favor of exalting decision making quality.
Fuzzy bicriteria multi-index transportation problems for coal allocation planning of Taipower
(1996-11-22)
Tzeng, GH
;
Teodorovic, D
;
Hwang, MJ
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
Taipower, the official electricity authority of Taiwan, encounters several difficulties in planning annual coal purchase and allocation schedule, e.g., with multiple sources, multiple destinations, multiple coal types, different shipping vessels, and even in uncertain demand and supply. In this study, these concerns are formulated as a fuzzy bicriteria multi-index transportation problem. Furthermore, an effective and interactive algorithm is proposed which combines reducing index method and interactive fuzzy multi-objective linear programming technique to cope with a complicated problem which may be prevalent in other industries. Results obtained in this study clearly demonstrate that this model can not only satisfy more of the actual requirements of the integral system but also offer more information to the decision makers (DMs) for reference in favor of exalting decision making quality.
Instantaneous normal mode analysis of liquid Na
(1996-11-22)
Wu, TM
;
Tsay, SF
;
物理研究所
;
Institute of Physics
The instantaneous-normal-mode (INM) densities of states for liquid Na in four realistic thermodynamic states are obtained by molecular-dynamics simulation. The exponent functions derived from the INM densities of states are found to fit well with a binomial of frequency for the imaginary-frequency lobe and a three-term polynomial for the real-frequency lobe. Through the study of the size dependence for the participation ratios of INMs, we show that for both the real-frequency and the imaginary-frequency lobes, INMs of low frequencies are extended modes and INMs in the high-frequency end are localized modes. However, each lobe has a broad transition region in frequency from the extended to localized INMs. (C) 1996 American Institute of Physics.
Instantaneous normal mode analysis of liquid Na
(1996-11-22)
Wu, TM
;
Tsay, SF
;
物理研究所
;
Institute of Physics
The instantaneous-normal-mode (INM) densities of states for liquid Na in four realistic thermodynamic states are obtained by molecular-dynamics simulation. The exponent functions derived from the INM densities of states are found to fit well with a binomial of frequency for the imaginary-frequency lobe and a three-term polynomial for the real-frequency lobe. Through the study of the size dependence for the participation ratios of INMs, we show that for both the real-frequency and the imaginary-frequency lobes, INMs of low frequencies are extended modes and INMs in the high-frequency end are localized modes. However, each lobe has a broad transition region in frequency from the extended to localized INMs. (C) 1996 American Institute of Physics.
Finding inheritance hierarchies in interval-valued fuzzy concept-networks
(1996-11-25)
Chen, SM
;
Horng, YJ
;
資訊工程學系
;
Department of Computer Science
This paper extends the work of Itzkovich and Hawkes (1994) to present the concepts of interval-valued fuzzy concept-networks and to present an algorithm for finding the collection of inheritance hierarchies in interval-valued fuzzy concept-networks, where the similarity relations and the generalization relations between concepts are represented by interval values in [0, 1]. The proposed method is more flexible than the one presented in Itzkovich and Hawkes (1994) due to the fact that it allows the grades of similarity relations and the generalization relations between concepts to be represented by interval-values rather than crisp real values between zero and one.
Nonoptical tip sample distance control for scanning near-field optical microscopy
(1996-11-25)
Chuang, YH
;
Wang, CJ
;
Huang, JY
;
Pan, CL
;
光電工程研究所
We propose and demonstrate a novel nonoptical technique for regulation of tip-sample distance in a scanning near-field optical microscope (SNOM). The fiber tip for the SNOM is attached to one prong of a quartz tuning fork. The fork is dithered with a gated sinusoidal signal. The vibration of the freely oscillating fiber tip, which manifests as the induced piezoelectric voltage on the fork electrodes, is monitored during the half-period of the gated sinusoid for which the fork is not driven. The time-multiplexing scheme, thus, allows the tuning fork to serve as a dither and a sensor with high Q factor, simultaneously. The gating technique could also potentially allow the SNOM to be used for the investigation of surface relaxation dynamics with high spatial resolution and submillisecond time resolution. (C) 1996 American Institute of Physics.
Nonoptical tip sample distance control for scanning near-field optical microscopy
(1996-11-25)
Chuang, YH
;
Wang, CJ
;
Huang, JY
;
Pan, CL
;
交大名義發表
We propose and demonstrate a novel nonoptical technique for regulation of tip-sample distance in a scanning near-field optical microscope (SNOM). The fiber tip for the SNOM is attached to one prong of a quartz tuning fork. The fork is dithered with a gated sinusoidal signal. The vibration of the freely oscillating fiber tip, which manifests as the induced piezoelectric voltage on the fork electrodes, is monitored during the half-period of the gated sinusoid for which the fork is not driven. The time-multiplexing scheme, thus, allows the tuning fork to serve as a dither and a sensor with high Q factor, simultaneously. The gating technique could also potentially allow the SNOM to be used for the investigation of surface relaxation dynamics with high spatial resolution and submillisecond time resolution. (C) 1996 American Institute of Physics.
青蘿蔔白蘿蔔紅蘿蔔
(1996-11-27)
介根氏
Comprehensive convergence study of TCAO close-coupling method for the excitation and ionization in keV H+-H collisions
(1996-11-28)
Kuang, JY
;
Lin, CD
;
物理研究所
;
Institute of Physics
Convergence of the two-centre atomic orbital (TCAO) close-coupling calculations for the excitation and ionization of atomic hydrogen by keV proton impact is carefully examined using various large basis sets on each centre; It is shown that reliable cross sections for the weak channels can only be obtained with a large number of basis states on the target and a limited number of bound states on the projectile. Cross sections for excitation to 2l, 3l, 4l and 5l states and for ionization are presented and compared to available experimental data and to other theoretical calculations.
The regular and chaotic motions of a symmetric heavy gyroscope with harmonic excitation
(1996-11-28)
Ge, ZM
;
Chen, HK
;
Chen, HH
;
機械工程學系
;
Department of Mechanical Engineering
The non-linear motion of a symmetric gyro mounted on a vibrating base is investigated, with particular emphasis on its long-term dynamic behaviour for a wide range of parameters. A single modal equation is used to analyze the qualitative behavior of the system. External disturbance appears as vertical harmonic motion of the support point and linear damping is assumed. The complete equation of motion is a non-linear non-autonomous one. The stability of the system has been studied by damped Mathieu equation theory and the Liapunov direct method. As the system is subjected to external disturbance, the Melnikov method is used to show the existence of chaotic motion. Finally, the bifurcation of the parameter dependent system is studied numerically. The time evolutions of the non-linear dynamical system responses are described in phase portraits via the Poincare map technique. The occurrence and the nature of chaotic attractors are verified by evaluating Liapunov exponents and average power spectra. The effect of the gyroscope's spinning speed is also studied, and it is shown that the gyroscope's spin velocity oz has a significant effect on the dynamic behavior of the motion. (C) 1996 Academic Press Limited
The regular and chaotic motions of a symmetric heavy gyroscope with harmonic excitation
(1996-11-28)
Ge, ZM
;
Chen, HK
;
Chen, HH
;
交大名義發表
;
機械工程學系
The non-linear motion of a symmetric gyro mounted on a vibrating base is investigated, with particular emphasis on its long-term dynamic behaviour for a wide range of parameters. A single modal equation is used to analyze the qualitative behavior of the system. External disturbance appears as vertical harmonic motion of the support point and linear damping is assumed. The complete equation of motion is a non-linear non-autonomous one. The stability of the system has been studied by damped Mathieu equation theory and the Liapunov direct method. As the system is subjected to external disturbance, the Melnikov method is used to show the existence of chaotic motion. Finally, the bifurcation of the parameter dependent system is studied numerically. The time evolutions of the non-linear dynamical system responses are described in phase portraits via the Poincare map technique. The occurrence and the nature of chaotic attractors are verified by evaluating Liapunov exponents and average power spectra. The effect of the gyroscope's spinning speed is also studied, and it is shown that the gyroscope's spin velocity oz has a significant effect on the dynamic behavior of the motion. (C) 1996 Academic Press Limited
Comprehensive convergence study of TCAO close-coupling method for the excitation and ionization in keV H+-H collisions
(1996-11-28)
Kuang, JY
;
Lin, CD
;
物理研究所
;
Institute of Physics
Convergence of the two-centre atomic orbital (TCAO) close-coupling calculations for the excitation and ionization of atomic hydrogen by keV proton impact is carefully examined using various large basis sets on each centre; It is shown that reliable cross sections for the weak channels can only be obtained with a large number of basis states on the target and a limited number of bound states on the projectile. Cross sections for excitation to 2l, 3l, 4l and 5l states and for ionization are presented and compared to available experimental data and to other theoretical calculations.
Operation optimization of Thiobacillus thioparus CH11 biofilter for hydrogen sulfide removal
(1996-11-29)
Chung, YC
;
Huang, CP
;
Tseng, CP
;
環境工程研究所
;
生物科技學系
Members of the autotrophic species, Thiobacillus thioparus CH11, were isolated from swine wastewater and immobilized with Ca-alginate to produce pellet packing materials for a novel biofilter system that controls hydrogen sulfide emission. The effect of operating parameters, including retention time, temperature, and inlet gas concentration, on the removal efficiency and capacity was evaluated. Criteria necessary for a scale-up design of the biofilter were established and the sulfur balances at various loadings were tabulated. High and satisfactory H2S removal efficiency levels were maintained during operation and the optimal retention time was found to be 28 a corresponding to a H2S removal efficiency greater than 98%. The pH drop was insignificant in this biofilter. The optimal inlet S-loading can be noted as 25 g m(-3) h(-1) that is at the upper end of linear correlation between inlet loading and removal capacity. We suggest that the Thiobacillus thioparus CH11 immobilized with Ca-alginate is a potent method to control hydrogen sulfide emissions. Copyright (C) 1996 Elsevier Science B.V.
Mechanism of transesterification and cyclization of epoxy-polycarbonate blends catalyzed by quarternary ammonium salt
(1996-11-30)
Li, MS
;
Ma, CCM
;
Lu, MS
;
Lin, ML
;
Chang, FC
The reaction of oxirane with carbonate using quarternary ammonium salts as catalyst has been studied. Curing is caused by the transesterification reaction of the oxirane cycle with the carbonate group that proceeds by an ''insertion'' mechanism in the stoichiometric system. The ratio of the reactants is two oxirane groups to one carbonate group. In the nonstoichiometric system, the epoxide content is more than the stoichiometric quantity required. A cyclization reaction is followed by the transesterification reaction. To identify the finished products, a model reaction was proposed using diphenyl carbonate and phenyl glycidyl ether which results in the formation of 4-phenoxymethyl-1,3-dioxolane-2-one (PMD). The mechanism of forming the cyclic structure is assumed to proceed through the chain scission of the network in which the molecular chain crosslinked with carbonate group by a transesterification reaction. (C) 1996 John Wiley & Sons,Inc.
藝術發源地
(1996-11-30)
不詳
Mechanism of transesterification and cyclization of epoxy-polycarbonate blends catalyzed by quarternary ammonium salt
(1996-11-30)
Li, MS
;
Ma, CCM
;
Lu, MS
;
Lin, ML
;
Chang, FC
The reaction of oxirane with carbonate using quarternary ammonium salts as catalyst has been studied. Curing is caused by the transesterification reaction of the oxirane cycle with the carbonate group that proceeds by an ''insertion'' mechanism in the stoichiometric system. The ratio of the reactants is two oxirane groups to one carbonate group. In the nonstoichiometric system, the epoxide content is more than the stoichiometric quantity required. A cyclization reaction is followed by the transesterification reaction. To identify the finished products, a model reaction was proposed using diphenyl carbonate and phenyl glycidyl ether which results in the formation of 4-phenoxymethyl-1,3-dioxolane-2-one (PMD). The mechanism of forming the cyclic structure is assumed to proceed through the chain scission of the network in which the molecular chain crosslinked with carbonate group by a transesterification reaction. (C) 1996 John Wiley & Sons,Inc.