Browsing by Issue Date, starting with "1992-11-19"

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THE WORST CASE ANALYSIS OF ALGORITHM ON MULTIPLE STACKS MANIPULATION
(1992-11-19)
CHIEN, BC
;
YANG, WP
;
資訊工程學系
;
Department of Computer Science
NONASSOCIATIVE PARALLEL PREFIX COMPUTATION
(1992-11-19)
CHEN, RJ
;
HOU, YS
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
Associativity of a binary operation allows many applications that are not possible with a non-associative binary operation. We propose a method to transform a binary expression into an associative one and present two related applications.
INFLUENCES OF HARMONIC COUPLING ON BIFURCATIONS IN DUFFING OSCILLATOR WITH BOUNDED POTENTIAL WELL
(1992-11-22)
KAO, YH
;
WANG, CS
;
YANG, TH
;
電信工程研究所
;
光電工程學系
DIAMOND FILM GROWTH ON CEMENTED TUNGSTEN CARBIDES STUDIED BY SEM, AES AND XPS
(1992-11-23)
CHEN, JL
;
HUANG, TH
;
PAN, FM
;
KUO, CT
;
CHANG, CS
Diamond films were deposited on cemented WC substrates using a hot filament chemical vapor deposition (CVD) system with a mixture of CH4 and H-2 as the source gases. The effect of the surface pretreatments of scratching the surface and etching to remove the surface Co from the substrate on diamond nucleation and growth was studied. The effect of CH4 Concentration on diamond growth was also examined. Scanning electron microscopy, Auger electron, X-ray photoelectron and energy dispersive spectroscopies were used to examine the film morphology, quality and compositions. The results show that a good diamond-crystal quality can be obtained by reducing the surface Co content in the substrate to below 1%. Co in the surface layer of the substrate inhibits both diamond nucleation and growth. Polishing and etching treatments to scratch the surface and to remove the surface Co of the substrates are essential to maintain the surface roughness in an appropriate range to obtain diamond films with a good quality and adhesion. A change in CH4 Concentration in the source gases from 0.5 to 0.15% can change the preferred orientation of the diamond films fro m the {100} to the {111} plane.
THE ROLE OF HYDROGEN IN DIAMOND SYNTHESIS FROM CARBON-DIOXIDE HYDROCARBON GASES BY MICROWAVE PLASMA CHEMICAL VAPOR-DEPOSITION
(1992-11-23)
CHEN, CF
;
HONG, TM
;
交大名義發表
;
材料科學與工程學系
;
National Chiao Tung University
We utilized carbon dioxide to replace hydrogen in CO2-(CH4, C2H2, C3H8) gas mixtures and studied the effect on diamond growth of adding a small amount of hydrogen to the system. The deposits were analyzed by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Our results showed that diamond film with high growth rate and good crystallinity could be obtained in these systems without supplying additional hydrogen gas. When the amount of hydrogen was increased, all the deposited film in the systems gradually displayed poorer morphology and crystallinity. This indicates that graphitic or amorphous carbon components in the diamond film increased with the addition of hydrogen, with a resulting negative effect on the quality of the diamond film. The influence of hydrogen on diamond growth is also investigated in this study by comparing growth rates and C:H:O ratios among various CO2-(CH4, C2H2, C3H8) systems.
GATE AND DRAIN CURRENTS IN OFF-STATE BURIED-TYPE P-CHANNEL LDD MOSFETS
(1992-12-01)
CHEN, MJ
;
CHAO, KC
;
HUANG, TH
;
TSAUR, JM
;
電控工程研究所
The buried-type p-channel LDD MOSFET's biased at high positive gate voltage exhibit new characteristics: 1) the ratio of the drain to gate currents is about 1 X 10(-3) to 5 X 10(-3); and 2) the gate and drain currents both are functions of only the gate voltage minus the n-well bias. Such characteristics are addressed based on the formation of the surface n+ inversion layer due to the punchthrough of the buried channel to the underlying shallow p-n junction. The measured gate current is due to the Fowler-Nordheim tunneling of electrons from this inversion layer surface and the holes generated within the high-field oxide constitute the drain current. The n+ inversion layer surface potential is found to be equal to the n-well bias plus 0.55 V. As a result, not only the oxide field but also the gate and drain currents are independent of drain voltage.
ORIENTATION-DEPENDENT X-RAY ABSORPTION FINE-STRUCTURE (XAFS) OF THE BI-SR-CA-CU-O SYSTEM
(1992-12-01)
CHOU, CH
;
PONG, WF
;
SHI, JB
;
KU, HC
;
LIN, IN
Using the transmission and fluorescence modes at the National Synchrotron Light Source (NSLS) X-23A2 beam line, we have measured polarized XAFS spectra of the Bi, Pb L3-edges and the Cu K-edge for the (Bi1.85Pb0.15)Ca2.2Sr1.8Cu3O10+delta sample and unpolarized XAFS spectra of the Bi, Pb L3-edges and the Cu K-edge for Bi2Ca1.2Sr1.8Cu2O8+delta, Pb0.2Bi1.9Sr1.9Cu1O6+delta and (PbxBi2-x)Sr2Ca2Cu3Oy (x = 0, 0.2, 0.4) samples. All XAFS spectra were measured at room temperature. The incommensurate modulations in the Bi-O layers are discussed in terms of the XAFS technique. The XAFS spectra of Bi L3-edge do not vary substantially for different sample orientation with respect to the X-ray polarization vector E. There is evidence for the existence within the Bi-Sr-Ca-Cu-O system of Bi atoms having the oxidation number exceeding 3. Pb ions predominantly substitute for Bi ions in the Bi-Sr-Ca-Cu-O system because there is no significant difference between the XANES spectra of the Pb and Bi L3-edges, respectively. The oxidation numbers of substituted Pb in Bi-Sr-Ca-Cu-O system differ much from those of Pb in PbO2 in which the oxidation number of all Pb atoms is 4. In agreement with other investigators, our results on the polarized XANES spectra of the Cu K-edge indicate that a satellite about 7 eV above the main K-XANES peak in both polarizations is a multielectron excitation to the final-state configuration 1s3d9epsilonp1, and that a shoulder on the rising absorption edge, present for many Cu compounds and generally assigned to a shake-down multielectron excitation, is a transition to a final state of the Cu compounds. We have also deduced that the structure of the Cu-O planes in the Bi-Sr-Ca-Cu-O samples is ordered.
SIZE EFFECT ON THE ELECTRICAL-CONDUCTION AND NOISE OF RUO2-BASED THICK-FILM RESISTORS
(1992-12-01)
CHIOU, BS
;
SHEU, JY
;
WU, WF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Temperature dependence of sheet resistance for a generic RuO2-based resistor with a composition of 20 wt.% RuO2-80 wt.% glass (63 wt.% PbO-25 wt.% B2O3-12 wt.% SiO2) is evaluated. A combined tunnel/parallel conduction model is employed to describe the resistance behavior with respect to the temperature variation. The geometry of the resistive film, such as the aspect ratio and thickness, cast a significant effect on the electrical characteristic of the thick film assembly. It is observed that shorter resistive films exhibit smaller resistivity as compared to that of the longer film. Thinner resistive films have smaller resistivity as compared to the thicker ones. In addition, 1/f noise is the dominating contribution in the thick film resistor. The presence of 1/f noise can be qualitatively explained with the aid of the tunneling mechanism.
EFFECT OF COPPER ADDITIVE ON THE MICROSTRUCTURE AND ELECTRICAL-PROPERTIES OF POLYCRYSTALLINE ZINC-OXIDE
(1992-12-01)
CHIOU, BS
;
CHUNG, MC
;
交大名義發表
;
電子工程學系及電子研究所
;
National Chiao Tung University
Nonohmic behavior is obtained for polycrystalline ZnO with copper as the only additive in the range 0.3 less-than-or-equal-to x less-than-or-equal-to 1 wt%. The effect of copper on the microstructure and electrical behavior of ZnO:Cu ceramics is investigated. The leakage current decreases and the breakdown electric field increases as the copper concentration increases. The large apparent dielectric constant of ZnO:Cu ceramic (k > > k(ZnO), k(ZnO) is the dielectric constant of pure ZnO) is attributed to the grain boundary barrier layer effect. A Schottky barrier height of 0.27-0.46 eV is obtained for various copper-added samples, depending on sintering temperatures.
HIGH-ORDER HARMONIC-GENERATION IN ATOMIC-HYDROGEN AT 248-NM - DIPOLE-MOMENT VERSUS ACCELERATION SPECTRUM
(1992-12-01)
JIANG, TF
;
CHU, SI
;
電子物理學系
;
Department of Electrophysics
We present a study of the high-order harmonic-generation (HG) spectra of atomic hydrogen at 248 nm based on the Fourier transform of the expectation values of the induced dipole moment and acceleration. The calculations were performed by extending a fast-Fourier-transformation split-operator technique (in spherical coordinates) to the solution of the time-dependent wave functions in intense laser fields. It is seen that the acceleration form provides a more satisfactory and accurate framework for the study of the photoemission HG spectrum at very intense fields, particularly when ionization becomes appreciable.
CHARACTERISTICS OF THE GAIN AND SIGNAL-TO-NOISE RATIO OF A DISTRIBUTED ERBIUM-DOPED FIBER AMPLIFIER
(1992-12-01)
WEN, SF
;
CHI, S
;
光電工程學系
;
Department of Photonics
The effects of the stimulated Ramam scattering (SRS) on the gain and signal-to-noise ratio (SNR) of the DEDFA with 100-km fiber length and with bidirectional pumps are numerically studied. It is found that the gain and SNR are significantly enhanced by the SRS with practical parameters. For 1.55-mum signal and 10-muW initial signal power, there are 8.8-dB gain enhancement and 3.3-dB SNR enhancement for 1.48-mum pump wavelength and 75-mW initial pump power. The characteristics of the gain and SNR enhancements due to SRS are studied for different signal wavelength, signal powers, pump wavelengths, pump powers, and effective fiber cross sections. The results show that the gain and SNR are decreased by SRS only for the unpractical high pump power and/or small effective fiber cross section.
A NEW METHODOLOGY FOR 2-DIMENSIONAL NUMERICAL-SIMULATION OF SEMICONDUCTOR-DEVICES
(1992-12-01)
CHIN, SP
;
WU, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A new methodology for obtaining the self-consistent solution of semiconductor device equations discretized in the finite-difference scheme is proposed, in which a new discretized Green's function solution method is used to solve the two-dimensional discretized Poisson's equation and a surface mapping technique is developed to treat arbitrary surface boundary conditions. As a result of the proposed new solution method, the two-dimensional potential distribution can be expressed in terms of charge density distribution and bias conditions. Using the derived potential distribution, the SLOR-nonlinear iteration for the current continuity equations of both carriers can be performed by incorporating with a new algorithm to get the self-consistent solution of full set of semiconductor device equations without any outer iteration. Comparisons between the proposed method and the Gummel's method in Si-MESFET simulation are made. It is demonstrated that the convergent rate of the proposed method can be speeded up to 4-8 times over the Gummel's method. The proposed new iterative method can be incorporated with the conventional solution method such as the Gummel's method to get a stable and efficient computation scheme for device simulation.
ONLINE METHOD FOR MEASUREMENT OF THE DISPERSION COEFFICIENT OF RADIONUCLIDE MIGRATION USING A COLUMN METHOD
(1992-12-01)
LIU, WC
;
LO, JG
;
TSAI, CM
;
環境工程研究所
;
Institute of Environmental Engineering
An On-line method to obtain breakthrough curves from a conservative tracer generated in crushed rock columns has been introduced. The breakthrough curve can be used to evaluate some important hydrologic Parameters for studying radionuclide migration in groundwater system. These parameters include the dispersion coefficient, average flow yelocity, effective porosity, and retardation factor of the columns tested. A conservative radiotracer, I-131, was used to generate the breakthrough curves, and linear regression analysis was applied to obtain the optimum value of dispersion coefficient. The effects of the injected volume of radioactive tracer, average flow velocity, and effective diameter of packed material on the dispersion coefficient as well as the stability of the packed material, and their in-situ application are discussed.
ON EQUIVALENT SYSTOLIC DESIGNS OF LU DECOMPOSITION AND ITS ALGEBRAIC REPRESENTATION
(1992-12-01)
HOU, YC
;
TSAY, JC
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
Algorithms which are to be mapped onto interconnecting processing elements in order to design a systolic array are conventionally represented by graphs or networks. This paper introduces the concept of algebraic representation and uses a generating function to represent a systolic array.
A 2-CHIP 1.5-GBD SERIAL LINK INTERFACE
(1992-12-01)
WALKER, RC
;
STOUT, CL
;
WU, JT
;
LAI, B
;
YEN, CS
A silicon bipolar transmitter and receiver chip pair transfers parallel data across a 1.5-GBd serial link. A new "conditional-invert master transition" code and phase-locked loop are described and analyzed that provide adjustment-free clock recovery and frame synchronization. The packaged parts require no external components and operate over a range of 700 to 1500 MHz using an on-chip VCO. The line code and handshake protocol have been accepted by the Serial-HIPPI implementor's group for serially transmitting 800-Mb/s HIPPI data, an ANSI standard, and by SCI-FI, an IEEE standard for interconnecting cooperating computers.
ACTIVATION MECHANISM OF IMPLANTED BORON IN A SI SUBSTRATE
(1992-12-01)
JUANG, MH
;
CHENG, HC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The recrystallization and dopant activation in the BF2+ implanted samples with a 110 keV/5 X 10(15) cm-2 condition into a Si substrate and annealed with different heating rates to various preset temperatures for zero holding time have been studied. A higher heating rate yielded a higher carrier mobility and a better crystallinity. A statistical model was proposed to characterize the dopant activation. The activated dopant concentration n was expressed as gamma exp(-E(a)/kT). The pre-exponential term gamma is a function of critical temperature T(c) due to a finite melting point of Si, and heating rate. Both the effective activation energy E(a) and T(c) values decreased with increasing heating rate. With increasing heating rate, the gamma term rapidly decreased at low rates due to the shortened effective annealing time, but showed slight increase at high rates due to the decreased T(c) value. Low heating rates facilitated the dopant activation via the gamma term, while high heating rates enhanced the activation efficiency via the E(a) term.
A NOVEL CONTROL ALGORITHM FOR RAPID AND PRECISE POSITIONING
(1992-12-01)
SHIEH, YS
;
LEE, AC
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
This paper investigates the positioning technology of a control system using an optimal control method. In this method, the control algorithm is based on minimization of a quadratic performance index, which consists of the position error and the weighted derivative of the error during a specific time interval. Minimization of this index allows us to obtain the optimal step control input command. It is shown that the control algorithm is efficient for positioning and simple for on-line implementation. The stability of the step control system is analyzed by the root locus method, and a means of selecting both the sampling period and the weighting matrix according to the specifications of the system is presented. Comparisons of the proposed control algorithm with bang-bang control and the optimum regulator problem are made. Also, a track-seeking servo control system of an optical disk driver is used to illustrate application of the proposed control method.
A VIDEO SIGNAL-PROCESSING TECHNIQUE FOR VIBRATION MEASUREMENT OF A FLEXIBLE BEAM
(1992-12-01)
TANG, PC
;
LU, SS
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A video system is used as a single contactless multipoint displacement sensor to measure the vibration displacement of a beam. In this article, several schemes are proposed to reduce the image processing time and to increase its accuracy. The vibration displacements of the entire beam are measured with a sampling rate of 60 Hz. From these measured data, the mode shapes and vibration states can be calculated. The video system is shown to have a potential for on-line control and on-line identification of flexible beam systems.
ONLINE METHOD FOR MEASUREMENT OF THE DISPERSION COEFFICIENT OF RADIONUCLIDE MIGRATION USING A COLUMN METHOD
(1992-12-01)
LIU, WC
;
LO, JG
;
TSAI, CM
;
環境工程研究所
;
Institute of Environmental Engineering
An On-line method to obtain breakthrough curves from a conservative tracer generated in crushed rock columns has been introduced. The breakthrough curve can be used to evaluate some important hydrologic Parameters for studying radionuclide migration in groundwater system. These parameters include the dispersion coefficient, average flow yelocity, effective porosity, and retardation factor of the columns tested. A conservative radiotracer, I-131, was used to generate the breakthrough curves, and linear regression analysis was applied to obtain the optimum value of dispersion coefficient. The effects of the injected volume of radioactive tracer, average flow velocity, and effective diameter of packed material on the dispersion coefficient as well as the stability of the packed material, and their in-situ application are discussed.
FAULT-TOLERANT ROUTING IN UNIQUE-PATH MULTISTAGE OMEGA NETWORK
(1992-12-10)
CHANG, HW
;
CHUNG, KL
;
資訊工程學系
;
Department of Computer Science
In this paper, two new near one-pass packet-routing schemes are proposed to tolerate all single faults among the switching boxes or the connecting links respectively in a unique-path multistage Omega network. Working in an undirected network, our results can compete with the two-pass routing scheme, which works in a directed network, proposed by Varma.