Browsing by Issue Date, starting with "1997-01-14"

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On-line algorithms for the dominating set problem
(1997-01-14)
King, GH
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Tzeng, WG
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資訊工程學系
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Department of Computer Science
Convergent TCAO close-coupling calculations for electron transfer, excitation and ionization in intermediate keV He2+-H collisions
(1997-01-14)
Kuang, JY
;
Lin, CD
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物理研究所
;
Institute of Physics
Our recently developed two-centre atomic orbital (TCAO) close-coupling method is applied to He2+-H(1s) collisions in the impact energy range from 20-400 keV amu(-1). Convergent cross sections are obtained for this system by using a large number of bound and pseudostate basis functions on the target and a limited number of bound states on the projectile. Cross sections for electron transfer to 1s, 2l, 3l, 4l and 5l, for excitation to 2l, 3l, 4l and 5l and for ionization are presented and compared with available experimental data and other theoretical calculations. The accuracy of the previous TCAO close-coupling calculations is challenged and the reliability of some experimental data for this system is questioned.
The exact gossiping problem
(1997-01-15)
Tsay, YJ
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Chang, GJ
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應用數學系
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Department of Applied Mathematics
This paper studies a variation of the gossiping problem, where there are n persons, each of whom initially has a message. A pair of persons can pass all messages they have by making one telephone call. The exact gossiping problem is to determine the minimum number of calls for each person to know exactly k messages. This paper gives solution to the problem for k less than or equal to 4 or i + 2(k - i - 2) less than or equal to n less than or equal to i - 2 + 2(k - i - 1) with k/2 - 1 less than or equal to i less than or equal to k - 4.
Passive mode-locking through nonlinear polarization rotation in low-birefringence fibers
(1997-01-15)
Chang, CW
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Chi, S
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光電工程學系
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Department of Photonics
A numerical model for the generation of ultrashort soliton pulses from erbium-doped fiber ring lasers is presented. The model is used to study the pulse dynamics of a simple cavity configuration that uses a low birefringence fiber combined with crossed polarizers. Simulations show that stable pulses with a FWHM as short as 70 fs can be generated. It is also shown that coherent coupling may enhance mode-locking in a weakly linearly birefringent fiber under optimum operation conditions, and in certain cases a period doubling bifurcation occurs due to residual linear birefringence in the fibers.
Polymer dose effects on filtration followed by expression of clay slurries
(1997-01-15)
Chang, IL
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Chu, CP
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Lee, DJ
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Huang, C
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環境工程研究所
Filtration followed by expression characteristics of cationic polymer conditioned clay slurries are reported for the first time in this work. As the polymer dosage increases, the resistance to filtration greatly decreases until a specific dose has been reached, where the zeta potential is close to zero. And further increase in polymer dose conversely raises the resistance. The expression data are interpreted by the Terzaghi-Voigt combined model, from which the model parameters are evaluated. The polymer conditioning has only a mild effect on the primary consolidation process but has, however, a considerable influence on secondary consolidation characteristics. When zeta potential changes from negative to positive, both the easiness of creeping of constituent particles within the sludge cake and the fraction of moisture removal by the secondary consolidation attain a maximum., The optimal polymer dose criterion considering the filtration and expression stages separately, or in combination, is (sic). (C) 1997 Academic Press
Thickness dependence of refractive index for anodic aluminium oxide films
(1997-01-15)
Chiu, RL
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Chang, PH
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材料科學與工程學系
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Department of Materials Science and Engineering
Minimum-maximum exclusive mean (MMEM) filter to remove impulse noise from highly corrupted images
(1997-01-16)
Han, WY
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Lin, JC
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
The minimum-maximum mean (MMEM) filter is presented to remove impulse noise from highly corrupted images. Simulation results show that even if the occurrence rate of the impulse noise is very high (70%), the restoration performance is still acceptable.
A modified interpolated cell mapping method
(1997-01-16)
Ge, ZM
;
Lee, SC
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
A modified interpolated cell mapping (MICM) method is developed for global analysis of deterministic dynamical systems with smooth basin boundaries. By improving the algorithm of the interpolated cell mapping (ICM) and including the idea of sampling mappings of cells from the generalized cell mapping (GCM), MICM gives a more complete and precise global analysis of systems than ICM. In addition, based on analysis using MICM, a method using exact mappings is proposed to remedy the inaccuracy and incompleteness of global analysis due to interpolated mappings and the assumption of the sink cell. For the three systems studied in this paper, this method locates identical attractors and basins of attraction as the integration of a grid of points (IGP) method, with a 100-fold improvement in computational efficiency. (C) 1997 Academic Press Limited.
中國最後一個太監「駕崩」
(1997-01-19)
管領風騷
Quinoxalino-fused sultines and their application in Diels-Alder reactions
(1997-01-21)
Chung, WS
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Liu, JH
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交大名義發表
;
應用化學系
;
National Chiao Tung University
The synthesis of 7,8-disubstituted quinoxalino[2,3-d]-[1,2 lambda(4)]oxathiine 2-oxides 7a-c, precursors for quinoxalino-o-quinodimethanes 3a-c, and their application in the Diels-Alder reactions are reported.
正義的怒吼熾熱了愛國的火把
(1997-01-23)
周穂穂
Determination of saikosaponins by micellar electrokinetic capillary chromatography
(1997-01-24)
Hsieh, YZ
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Huang, HY
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應用化學系
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Department of Applied Chemistry
In this study, we examine the feasibility of determining saikosaponins a, b1, b2, c and d, i.e., the bioactive components in Bupleuri Radix, using the micellar electrokinetic capillary chromatography technique. Results obtained from using different anion surfactants, bile salt or sodium dodecyl sulfate (SDS), are also compared. By using bile salt as a pseudostationary phase, the baseline separation of saikosaponins is observed; however, the detection limit is unfavorable. Whereas the baseline resolution of saikosaponins is achieved after adding gamma-cyclodextrin in the SDS running buffer. In addition, another separating method is developed with the mixed micellar system of SDS and Brij 35 containing gamma-cyclodextrin. The contents of saikosaponins in traditional Chinese medicinal prescriptions, such as Sheau Chair Hwu Tang, Bupleuri Radix plant and Chair Hwu San are analyzed by one of the above methods. The entire separation can be completed within 9 min by these methods. The R.S.D. values of the migration times are all below 1%. Moreover, the detection limits of saikosaponins vary from 7 to 33 mu g/ml.
Determination of saikosaponins by micellar electrokinetic capillary chromatography
(1997-01-24)
Hsieh, YZ
;
Huang, HY
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
In this study, we examine the feasibility of determining saikosaponins a, b1, b2, c and d, i.e., the bioactive components in Bupleuri Radix, using the micellar electrokinetic capillary chromatography technique. Results obtained from using different anion surfactants, bile salt or sodium dodecyl sulfate (SDS), are also compared. By using bile salt as a pseudostationary phase, the baseline separation of saikosaponins is observed; however, the detection limit is unfavorable. Whereas the baseline resolution of saikosaponins is achieved after adding gamma-cyclodextrin in the SDS running buffer. In addition, another separating method is developed with the mixed micellar system of SDS and Brij 35 containing gamma-cyclodextrin. The contents of saikosaponins in traditional Chinese medicinal prescriptions, such as Sheau Chair Hwu Tang, Bupleuri Radix plant and Chair Hwu San are analyzed by one of the above methods. The entire separation can be completed within 9 min by these methods. The R.S.D. values of the migration times are all below 1%. Moreover, the detection limits of saikosaponins vary from 7 to 33 mu g/ml.
On the complexity of point-in-polygon algorithms
(1997-02-01)
Huang, CW
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Shih, TY
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土木工程學系
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Department of Civil Engineering
Point-in-polygon is one of the fundamental operations of Geographic Information Systems. A number of algorithms can be applied. Different algorithms lead to different running efficiencies. In the study, the complexities of eight point-in-polygon algorithms were analyzed. General and specific examples are studied. In the general example, an unlimited number of nodes are assumed; whereas in the second example, eight nodes are specified. For convex polygons, the sum of area method, the sign of offset method, and the orientation method is well suited for a single point query. For possibly concave polygons, the ray intersection method and the swath method should be selected. For eight node polygons, the ray intersection method with bounding rectangles is faster. (C) 1997 Elsevier Science Ltd.
Modeling techniques for large-scale PCS networks
(1997-02-01)
Lin, YB
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資訊工程學系
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Department of Computer Science
Over the past few years there has been rapid growth in the demand for mobile communications that has led to intensive research and development of complex PCS (personal communication services) networks. Capacity planning and performance modeling are necessary to maintain a high quality of service to the PCS subscriber while minimizing costs. Effective and practical performance models for large-scale PCS networks are currently available. Two new performance models are presented in this article which can be solved using analytical techniques. The first is the so-called portable population model, based on the flow equivalent assumption (the rate of portables into a cell equals the rate of portables out of the cell). The model provides the steady-state portable population distribution in a cell that is independent of the portable residual time distribution, which can be used by simulations to reduce the necessary execution time by reaching the steady state more rapidly. Additionally, this model can be used to study the blocking probability of a low (portable) mobility PCS network and the performance of portable deregistration strategies. The second model is the so-called portable movement model which can be used to study location tracking and handoff algorithms. The model assumes that the arriving calls to a portable form a Poisson process, and portable residual times have a general distribution. This model can be used to study location-tracking algorithms and handoff algorithms. it is shown that under some assumptions, the analytic techniques are consistent with the simulation model.
Unsteady vortex roll structures in a mixed convective air flow through a horizontal plane channel: A numerical study
(1997-02-01)
Yu, CH
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Chang, MY
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Huang, CC
;
Lin, TF
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機械工程學系
A three-dimensional unsteady numerical simulation was conducted to investigate the buoyancy induced vortex how structures in a forced air flow through a bottom heated horizontal plane channel. In particular, a third-order upwind finite difference scheme was chosen to solve the Navier-Stokes and energy equations. In the ranges of the Reynolds number Re from 20 to 50 and Rayleigh number Ra up to 31 000, several roll structures were predicted. In the steady flow at high Re and low Ra after the initial transient the longitudinal rolls possess spanwise symmetry and grow regularly to a fully developed state as it proceeds downstream. While in the time periodic flow at low Re and high Ra the rolls may tilt towards the right side wall and the flow is asymmetric or they may tilt to both sides and are symmetric, depending on the particular case studied. This roll tilting causes the rolls to terminate as they encounter the side walls. Meanwhile, new space is provided in the region near the other side of the duct or near the central vertical plane for the generation of new cells. It is also noted that the rolls are wavy in axial direction. Moreover, the rolls change their sizes during moving downstream and no fully developed state can be discerned. Based on the present data, correlating equations for the onset of convection and Hopf bifurcation were proposed. Copyright (C) 1996 Elsevier Science Ltd.
Resist-related damage on ultrathin gate oxide during plasma ashing
(1997-02-01)
Chien, CH
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Chang, CY
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Lin, HC
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Chang, TF
;
Chiou, SG
This paper presents an important observation of plasma-induced damage on ultrathin oxides during O-2 plasma ashing by metal ''antenna'' structures with photoresist on top of the electrodes, It is found that for MOS capacitors without overlying photoresist during plasma ashing, only minor damage occurs on thin oxides, even for oxide thickness down to 4.2 nm and an area ratio as large as 10(4), In contrast, oxides thinner than 6 nm with resist overlayer suffer significant degradation from plasma charging, This phenomenon is contrary to most previous reports, It suggests that the presence of photoresist will substantially affect the plasma charging during ashing process, especially for devices with ultrathin gate oxides.
Chemical transformations of 4,6-dimethyl-2 beta-hydroxy-8-oxo-3,5,7-trioxatetracyclo[7.2.1.0(4,11).0(6,10)]dodecane
(1997-02-01)
Chem, JH
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Wu, HJ
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交大名義發表
;
應用化學系
;
National Chiao Tung University
Reactions of 4,6-dimethyl-2 beta-hydroxy-8-oxo-3,5,7-trioxatetracyclo-[7.2.1.0(4,11).0(6,10)] dodecane 1 with nucleophiles have been studied. Reaction of 1 with alcohols, triethylsilane, allyltrimethylsilane,and methylthiotrirnethylsilane in CH2Cl2 in the presence of TiCl4 gave the substitution products 2, 7a, 7b, and 7c in 80-90% yields. The substitution reaction took place chemoselectively on the hemiacetal group of 1. Reaction of 1 with cyanotrimethylsilane in CH2Cl2 in the presence of TiCl4 gave compound 8 and the rearranged product 9. The structure of 9 was proven by X-ray analysis.
The design of a 3-V 900-MHz CMOS bandpass amplifier
(1997-02-01)
Wu, CY
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Hsiao, SY
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
A new bandpass amplifier which performs both functions of low-noise amplifier (LNA) and bandpass filter (BPF) is proposed for the application of 900-MHz RF front-end in wireless receivers, In the proposed amplifier, the positive-feedback Q-enhancement technique is used to overcome the low-gain low-Q characteristics of the CMOS tuned amplifier, The Miller capacitance tuning scheme is used to compensate for the process variations of center frequency, Using the high-Q bandpass amplifier in the receivers, the conventional bulky off-chip filter is not required, An experimental chip fabricated by 0.8-mu m N-well double-poly-double-metal CMOS technology occupies 2.6 x 2.0 mm(2) chip area, Under a 3 V supply voltage, the measured quality factor is tunable between 2.2 and 44. When the quality factor is tuned at Q = 30, the measured center frequency of the amplifier is tunable between 869-893 MHz with power gain 17 dB, noise figure 6.0 dB, output 1 dB compression point at -30 dBm, third-order input intercept point at -14 dBm, and power dissipation 78 mW.
Characterization of an isozyme of beta-glucosidase from sweet almond
(1997-02-01)
Li, YK
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Chang, LF
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Shu, HH
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Chir, J
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交大名義發表
A sweet almond beta-glucosidase (EC 3.2.1.21) isozyme was purified from commercial crude product. The process of purification consisted of a Protein-Pak Q anion exchange chromatography following by a Superdex 75 HR gel filtration separation. The purified enzyme is a monomeric glycoprotein with molecular weight of 58 kDa and pI = 4.55 which is distinguished from reported isozymes. The enzyme has a pH optimum in the range of 5.2-5.6 when p-nitrophenyl-beta-D-glycopyranosides are used as substrate and is stable up to 50 degrees C at that pH range. The purified protein also exhibits profound beta-galactosidase and alpha-L-arabinosidase activity. The study of substrate specificity revealed that lacking of hydroxymethyl group at C-5 of glycosides resulted in higher affinity for substrate binding to enzyme, whereas the chemical step of hydrolysis (k(cat)) was prevented significantly. The pH activity profile displayed a bell-shaped curve for all measured p-nitrophenyl-beta-D-glycopyranosides with apparent pK(1) and pK(2) values of 4.4-4.7 and 6.2-6.4, respectively. This isozyme was strongly inhibited by delta-gluconolactone (K-i = 160 mu M) and 4-phenylimidazole (K-i = 17.8 mu M) reversibly at pH 6.2. Among the tested glycoses, the binding affinity of N-acetyl-beta-D-glucosamine to the enzyme (K-i = 52 mM) was 6 times stronger than that of glucose and its epimers.