Browsing by Issue Date, starting with "1997-04-13"

Now showing 1 - 20 of 83839

Convenient synthesis of tavacpallescensin and occidol.
(1997-04-13)
Ho, TL
;
Lin, YJ
;
應用化學系
;
Department of Applied Chemistry
Synthesis of anisotropic polymer films for display applications
(1997-04-13)
Hsu, CS
;
Chen, HL
;
應用化學系
;
Department of Applied Chemistry
Laser-excited luminescence study of aqueous solution properties of the Eu3+-D02A system
(1997-04-13)
Chang, CA
;
Chen, YH
;
生物科技學系
;
Department of Biological Science and Technology
Effects of polymer dosage on alum sludge dewatering characteristics and physical properties
(1997-04-14)
Wu, CC
;
Huang, CP
;
Lee, DJ
;
環境工程研究所
;
Institute of Environmental Engineering
The proper use of polymers as conditioners is a critical aspect of dewatering processes. In this study, we investigate their physical properties, i.e. size, density and fractal dimension and correlate them with their dewatering characteristics (bound water content, CST and SRF) on alum sludge with cationic polymer conditioning. Using CST measurement to determine the optimum polymer dose may lead to an over-dosing for polymer conditioned sludge. Bound water depletion and interstitial water formation significantly affect the moisture content during polymer conditioning. Moreover, the magnitude of bound water content reflects net change in moisture content, which is decreased by bound water depletion and increased by water formation. Flee size and density measurement suggest poor dewatering performance and increased bound water content are attributable to enlargements in flee size and decreases in flee density. Experimental results indicate that increases in bound water and decreases in flee density are caused by variations of both flee size and aggregation configuration type, not degree of flee compactness.
The AS-quenched microstructures of Fe-9Al-30Mn-1.2C-xSi alloys
(1997-04-15)
Hwang, CN
;
Liu, TF
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The AS-quenched microstructures of Fe-9Al-30Mn-1.2C-xSi alloys
(1997-04-15)
Hwang, CN
;
Liu, TF
;
交大名義發表
;
材料科學與工程學系
;
National Chiao Tung University
Nitridation of fine grain chemical vapor deposited tungsten film as diffusion barrier for aluminum metallization
(1997-04-15)
Chang, KM
;
Yeh, TH
;
Deng, IC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A novel tungsten nitride (WNx) film for diffusion barrier applications has been prepared by nitridation of a fine grain chemical vapor deposited tungsten (CVD-W) film. The fine grain CVD-W is deposited at 300 degrees C in a low pressure chemical vapor deposition reactor with a SiH4/WF6 flow rate of 12.5/5 seem under a total gas pressure of 100 mTorr. The subsequent nitridation process is executed in nitrogen plasma at 300 degrees C without breaking vacuum. The thickness of WN, layer as examined by secondary ion mass spectroscopy is 50 nm after 5 min exposure to nitrogen plasma. X-ray photoelectron spectroscopy spectra shows that the atomic ratio of tungsten to nitrogen in WNx, layer is 2:1. According to the analysis by Auger electron spectroscopy and the measurement of n(+)p junction leakage current, the Al/WNx/W/Si multilayer maintains excellent interfacial stability after furnace annealing at 575 degrees C for 30 min. The effectiveness of W2N barrier is attributed to stuffing grain boundaries with nitrogen atoms which eliminates the rapid diffusion paths in fine grain CVD-W films. (C) 1997 American Institute of Physics.
Thermodynamic parameters of iron-cyanide adsorption onto gamma-Al2O3
(1997-04-15)
Huang, CP
;
Cheng, WP
;
環境工程研究所
;
Institute of Environmental Engineering
In this study, we describe the adsorption of ferricyanide (Fe(CN)(6)(3-)) on gamma-Al2O3 by a modified Langmuir adsorption isotherm. The modified Langmuir isotherm developed herein can accurately predict the apparent equilibrium constant (K-app) at different pH values and temperatures. In the experimental pH range of 5-6.5, adsorption capacity and apparent equilibrium constants decrease as the temperature increases. Because surface protonation increases as pH decrease, a more positively charged site on the surface increases the attraction force that exists between gamma-Al2O3 and the adsorbate. According to the Gibbs-Hehmholtz equation, these apparent equilibrium constants at various temperatures and pH conditions can be applied to determine enthalpy changes (Delta H-0) for the adsorption at different pH conditions. The result indicates that enthalpy change at different pH values is near -5 kcal/mol which indicates that the enthalpy change is in the order of hydrogen bonding and confirms the exothermic nature of the adsorption process. The results also indicate that other thermodynamic parameters change of ferricyanide adsorption. The positive entropy change (Delta S-0) has been explained from the viewpoint of exchange reaction in this study. The negative free energy change (Delta G(ads)(0)) for ferricyanide adsorption shows the spontaneous nature of the adsorption process. (C) 1997 Academic Press.
Thermodynamic parameters of iron-cyanide adsorption onto gamma-Al2O3
(1997-04-15)
Huang, CP
;
Cheng, WP
;
交大名義發表
;
環境工程研究所
;
National Chiao Tung University
In this study, we describe the adsorption of ferricyanide (Fe(CN)(6)(3-)) on gamma-Al2O3 by a modified Langmuir adsorption isotherm. The modified Langmuir isotherm developed herein can accurately predict the apparent equilibrium constant (K-app) at different pH values and temperatures. In the experimental pH range of 5-6.5, adsorption capacity and apparent equilibrium constants decrease as the temperature increases. Because surface protonation increases as pH decrease, a more positively charged site on the surface increases the attraction force that exists between gamma-Al2O3 and the adsorbate. According to the Gibbs-Hehmholtz equation, these apparent equilibrium constants at various temperatures and pH conditions can be applied to determine enthalpy changes (Delta H-0) for the adsorption at different pH conditions. The result indicates that enthalpy change at different pH values is near -5 kcal/mol which indicates that the enthalpy change is in the order of hydrogen bonding and confirms the exothermic nature of the adsorption process. The results also indicate that other thermodynamic parameters change of ferricyanide adsorption. The positive entropy change (Delta S-0) has been explained from the viewpoint of exchange reaction in this study. The negative free energy change (Delta G(ads)(0)) for ferricyanide adsorption shows the spontaneous nature of the adsorption process. (C) 1997 Academic Press.
Nitridation of fine grain chemical vapor deposited tungsten film as diffusion barrier for aluminum metallization
(1997-04-15)
Chang, KM
;
Yeh, TH
;
Deng, IC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A novel tungsten nitride (WNx) film for diffusion barrier applications has been prepared by nitridation of a fine grain chemical vapor deposited tungsten (CVD-W) film. The fine grain CVD-W is deposited at 300 degrees C in a low pressure chemical vapor deposition reactor with a SiH4/WF6 flow rate of 12.5/5 seem under a total gas pressure of 100 mTorr. The subsequent nitridation process is executed in nitrogen plasma at 300 degrees C without breaking vacuum. The thickness of WN, layer as examined by secondary ion mass spectroscopy is 50 nm after 5 min exposure to nitrogen plasma. X-ray photoelectron spectroscopy spectra shows that the atomic ratio of tungsten to nitrogen in WNx, layer is 2:1. According to the analysis by Auger electron spectroscopy and the measurement of n(+)p junction leakage current, the Al/WNx/W/Si multilayer maintains excellent interfacial stability after furnace annealing at 575 degrees C for 30 min. The effectiveness of W2N barrier is attributed to stuffing grain boundaries with nitrogen atoms which eliminates the rapid diffusion paths in fine grain CVD-W films. (C) 1997 American Institute of Physics.
A PD-like self-tuning fuzzy controller without steady-state error
(1997-04-16)
Chao, CT
;
Teng, CC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a PD-like self-tuning fuzzy controller (STFC) based on the tuning of scaling factors. A two-stage tuning method including a direct tuning stage and indirect tuning stage is proposed. For most linear controlled plants, application of the direct tuning stage alone is enough to yield satisfactory system responses. The proposed STFC can automatically detect the operating ranges of input variables and then adjust the scaling factors. In the indirect tuning stage the back-propagation algorithm can be directly applied to fine-tune the scaling factors when a more complicated plant is controlled. Furthermore, a simple but efficient method for fully compensating for steady-state error, which is the main problem in a PD-like fuzzy logic control system, is proposed so that tuning for fuzzy logic rule bases is unnecessary. Simulation results with linear time-invariant systems and a nonlinear unstable system as the controlled plants show that the proposed technique yields zero steady-state error responses very quickly without overshoot or oscillatory behavior. (C) 1997 Elsevier Science B.V.
A PD-like self-tuning fuzzy controller without steady-state error
(1997-04-16)
Chao, CT
;
Teng, CC
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
This paper presents a PD-like self-tuning fuzzy controller (STFC) based on the tuning of scaling factors. A two-stage tuning method including a direct tuning stage and indirect tuning stage is proposed. For most linear controlled plants, application of the direct tuning stage alone is enough to yield satisfactory system responses. The proposed STFC can automatically detect the operating ranges of input variables and then adjust the scaling factors. In the indirect tuning stage the back-propagation algorithm can be directly applied to fine-tune the scaling factors when a more complicated plant is controlled. Furthermore, a simple but efficient method for fully compensating for steady-state error, which is the main problem in a PD-like fuzzy logic control system, is proposed so that tuning for fuzzy logic rule bases is unnecessary. Simulation results with linear time-invariant systems and a nonlinear unstable system as the controlled plants show that the proposed technique yields zero steady-state error responses very quickly without overshoot or oscillatory behavior. (C) 1997 Elsevier Science B.V.
Deposition of indium tin oxide films on polycarbonate substrates by radio-frequency magnetron sputtering
(1997-04-20)
Wu, WF
;
Chiou, BS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Indium tin oxide (ITO) films have been deposited onto polycarbonate (PC) substrates by radio frequency (rf) magnetron sputtering. The influence of the oxygen content during sputtering on the film morphology, and the electrical and optical properties of the films have been investigated. Both the refractive index and the extinction coefficient decrease with increasing oxygen content. In this study, the figures of merit T-10/R-sh of the films are higher than those for low-temperature sputtered films reported in the literature. (C) 1997 Elsevier Science S.A.
Cooperative behavior of RVB, flux phase, and antiferromagnetic states
(1997-04-20)
Chiueh, HL
;
Chuu, DS
;
電子物理學系
;
Department of Electrophysics
The coexistence of RVB, flux phase, and antiferromagnetic states for the t-J model is studied within the frame work of the mean-field theory by means of the slave-boson approach. Two simple relations among these three order parameters manifesting the cooperative behavior of these states are derived. A phase diagram separating the antiferromagnetic from the non-antiferromagnetic stale is obtained. Comparison with available previous work shows that our result agrees reasonably well. (C) 1997 Elsevier Science B.V.
Deposition of indium tin oxide films on polycarbonate substrates by radio-frequency magnetron sputtering
(1997-04-20)
Wu, WF
;
Chiou, BS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Indium tin oxide (ITO) films have been deposited onto polycarbonate (PC) substrates by radio frequency (rf) magnetron sputtering. The influence of the oxygen content during sputtering on the film morphology, and the electrical and optical properties of the films have been investigated. Both the refractive index and the extinction coefficient decrease with increasing oxygen content. In this study, the figures of merit T-10/R-sh of the films are higher than those for low-temperature sputtered films reported in the literature. (C) 1997 Elsevier Science S.A.
Effects of analyte-matrix interactions on supercritical fluid extraction efficiencies of polycyclic aromatic hydrocarbons
(1997-04-21)
Hsieh, YZ
;
Chang, AC
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
The effects of different variables for analyte-matrix interactions on supercritical fluid extraction (SFE) efficiencies of polycyclic aromatic hydrocarbons (PAHs) were investigated. The results indicated that the main factors for describing a matrix, e.g., the chemical properties of the matrix surface, surface area, and pore size, could significantly influence the analyte-matrix interactions. The polarizability of an analyte was demonstrated to be yet another significant factor for influencing analyte-matrix interactions. Either elevating the temperature or adding modifiers could also increase the SFE recoveries. The underlying mechanisms of these variables are discussed.
A novel one-pot conversion of tetraacetal tetraoxa-cages to aza-cages mediated by iodotrimethylsilane in acetonitrile
(1997-04-21)
Wu, HJ
;
Chern, JH
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
Treatment of the tetraacetal tetraoxa-cages 1a-f with excess of iodotrimethylsilane in acetonitrile at 25 degrees C gave the novel tetraacetal trioxamonoaza-cages 2a-f in 75-80% yields respectively, a novel one-pot conversion of era-cages to ata-cages. (C) 1997 Elsevier Science Ltd.
A novel one-pot conversion of tetraacetal tetraoxa-cages to aza-cages mediated by iodotrimethylsilane in acetonitrile
(1997-04-21)
Wu, HJ
;
Chern, JH
;
應用化學系
;
Department of Applied Chemistry
Treatment of the tetraacetal tetraoxa-cages 1a-f with excess of iodotrimethylsilane in acetonitrile at 25 degrees C gave the novel tetraacetal trioxamonoaza-cages 2a-f in 75-80% yields respectively, a novel one-pot conversion of era-cages to ata-cages. (C) 1997 Elsevier Science Ltd.
Determination of preservatives in food products by cyclodextrin-modified capillary electrophoresis with multiwavelength detection
(1997-04-25)
Kuo, KL
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
A high-performance capillary electrophoretic method with multiwavelength detection was developed to analyze frequently used preservatives. The effects of alpha-cyclodextrin and beta-cyclodextrin on migration behaviours of nine preservatives were investigated. The preservatives were successfully separated within 9 min using a borax-NaOH buffer (pH 10.0) modified with 2 mM alpha-cyclodextrin. In optimized separation conditions, the reproducibilities of the migration times of the preservatives were satisfactory (R.S.D. values <0.99%). The correlation coefficients of the linear calibration graphs for the preservatives, ranging between 5 and 500 mu g ml(-1), exceeded 0.991. By employing this reliable capillary electrophoresis method, preservatives in three different food products were determined.
Blind identification and deconvolution algorithms using higher-order cumulants
(1997-05-01)
Ueng, FB
;
Su, YT
;
電信工程研究所
;
Institute of Communications Engineering
The use of second-order statistics in identification or deconvolution incurs error due to additive Gaussian noise. In contrast, higher-order statistics (HOS) are insensitive to Gaussian perturbation and can be used to characterize nonminimum phase (NMP) systems. In this paper we propose batch, recursive and adaptive form algorithms based on third- and fourth-order cumulants to solve the identification and deconvolution problems. A new order determination procedure is also presented. Simulation results demonstrate that our algorithms do have superior performance when compared with existing algorithms.