Browsing by Issue Date, starting with "1992-09-15"

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INFLUENCE OF THIN PROTECTIVE INAS LAYERS ON THE OPTICAL-QUALITY OF ALGAAS AND QUANTUM-WELLS
(1992-09-15)
TSAI, KL
;
CHANG, KH
;
LEE, CP
;
HUANG, KF
;
CHANG, Y
Influence of a thin protective but subsequently evaporated InAs layer on the regrowth of AlGaAs has been studied. It was found tha although most of the InAs could be evaporated by thermal desorption, some would react with Al0.36Ga0.64As to form InAlGaAs. These InAlGaAs islands act as potential wells for carrier recombination and dominate the photoluminescence spectrum. Transmission electron microscopy photographs show that dislocations are formed near the islands. These defects are caused by lattice mismatch between AlGaAs and InAlGaAs. These islands and defects strongly affect the optical quality of surrounding Al0.36Ga0.64As and quantum wells.
DOUBLE PHASE MODULATION APPROACH TO AN INTERFEROMETRIC SYSTEM
(1992-09-15)
CHIEN, PY
;
PAN, RP
;
PAN, CL
;
交大名義發表
;
光電工程學系
A novel method for measuring the phase difference between interfering beams in an interferometric system is demonstrated by using a double phase modulation technique. There are two modulation signals applied to the interferometric system. The first modulation signal is used to modulate the path length for pseudo-heterodyne processing. The second modulation signal is used to modulate the frequency of the laser diode for equivalent wavelength synthesis. This approach is demonstrated by using a fiberoptic Mach-Zehnder interferometer.
CONVENTIONAL FURNACE AND RAPID THERMAL ANNEALING OF COBALT FILMS ON SI(111)
(1992-09-15)
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 effects of conventional furnace annealing (CFA) and rapid thermal annealing (RTA) on the interfacial reactions of thin cobalt films on Si(111) have been investigated. The low heating rates (about 10-degrees-C s-1) associated with CFA lead to impurity segregation at the silicide-Si interface during the initial stage of interfacial reactions, while segregation is absent for high heating rates (about 100-degrees-C s-1) associated with RTA. From examination by transmission electron microscopy (TEM), RTA promotes uniform formation of silicides and epitaxial growth of twin-structure CoSi2, causing an average grain size of about 50 nm and a surface coverage area of about 70% at 500-600-degrees-C for 100-600 s. In contrast. silicidation is retarded for CFA, and grain growth is preferred to formation of epitaxial CoSi2. The electrical characterization of low doping level silicided shallow junctions correlates well with the TEM examinations of the interfacial reactions by the respective annealing schemes.
OPTIMAL INCIDENT CONDITIONS FOR A CAT-TYPE SELF-PUMPED PHASE-CONJUGATE MIRROR
(1992-09-20)
SUN, CC
;
YEH, S
;
CHANG, MW
;
HSU, KY
;
光電工程學系
We present a simplified method, based on experimental observations, for predicting the best incident conditions for obtaining the highest reflectivity of a Cat-type self-pumped phase conjugator with given crystal dimensions.
DISTRIBUTIONAL AND INFERENTIAL PROPERTIES OF PROCESS CAPABILITY INDEXES
(1992-10-01)
PEARN, WL
;
KOTZ, S
;
JOHNSON, NL
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In this paper we survey and critically comment on some basic concepts and notions relevant to the methodology dealing with process capability indices (PCI's). The emphasis is on distributional and inferential aspects. The intent is to contribute to the understanding and interpretation of these indices, if one is (unfortunately) required to use them. We regard them primarily as indicators of the expected proportion of nonconforming items, and not as having some relationship to arbitrary loss functions, as is currently the more fashionable viewpoint. New PCI's, related to the expected proportion of nonconforming items, are suggested.
CHARACTERIZATION OF SILICIDED SHALLOW N+P JUNCTIONS FORMED BY P+ IMPLANTATION INTO THIN TI FILMS ON SI SUBSTRATES
(1992-10-01)
JUANG, MH
;
CHENG, HC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
High-quality silicided shallow n+p junctions have been fabricated by P+ implantation into thin Ti films on Si substrates and by moderate implant conditions as well as subsequent high-temperature rapid thermal annealing (RTA) followed by low-temperature conventional furnace annealing (CFA). RTA minimizes the diffusion of knock-on Ti but greatly reduces the drive-in efficiency because of its short annealing time. Driving the dopants out of silicides via long-time annealing was associated with the crystallinity of silicides. The junctions formed by this scheme with respect to various implant and anneal conditions have been characterized. In addition, the distribution profile of Ti penetration was correlated with the effective generation life time obtained from the reverse I-V curves.
AN OPTIMAL VARIABLE STRUCTURE CONTROL WITH INTEGRAL COMPENSATION FOR ELECTROHYDRAULIC POSITION SERVO CONTROL-SYSTEMS
(1992-10-01)
CHERN, TL
;
WU, YC
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
An approach employing variable structure control with integral compensation is presented for an electrohydraulic position servo control system to achieve accurate servo tracking in the presence of load disturbance and plant parameter variation. Simulations show that the proposed approach may give a rather accurate servo-tracking result and is fairly robust to plant parameter variation and load disturbance.
ASYMMETRIC MODULATION INDEXES IN FULL PARTIAL RESPONSE MULTI-H PHASE-CODED MODULATIONS WITH DIFFERENT PHASE PULSE FUNCTIONS
(1992-10-01)
LEE, LS
;
HWANG, HK
;
CHEN, SH
;
傳播研究所
;
Institute of Communication Studies
A new concept of asymmetric modulation indices has recently been proposed and applied to full response multi-H phase-coded modulations (MHPM) with linear phase pulse function, and improved error probability performance has been found. In the paper, the above concept is extended in two directions. The partial response performance is analysed and compared with full response systems, and the effect of different phase pulse functions on bandwidth/power efficiency is discussed in detail. It is shown that not only is improved performance possible, but also a full range of design trade-offs, among bandwidth and power efficiencies and complexity, are available for system optimisation.
ENERGY PLANNING AND ENVIRONMENTAL-QUALITY MANAGEMENT - A DECISION SUPPORT SYSTEM APPROACH
(1992-10-01)
LIU, BC
;
TZENG, GH
;
HSIEH, CT
;
交大名義發表
;
National Chiao Tung University
This paper describes a computer-based decision support system (DSS) for evaluating quality, of life (QOL) improvement in general, and technological and environmental impacts of energy planning and consumption in particular. Based primarily on information obtained from the Environmental Protection Administration and the Energy Committee, Ministry of Economic Affairs of ROC, the variations in economic growth and overall life quality changes in Taiwan may be quantitatively assessed and performance indexes for various socioeconomic, political, environmental, energy and technological aspects constructed using historical and extrapolated time series data. The interdependent relationships and cross-impacts among energy planning, patterns of energy production and consumption, and 'trade-off' decisions in environmental quality management may be objectively tested and analysed. This approach is designed to support and enhance strategical decision-makers in a more organized and efficient manner for semi-structured tasks and/or problem solving, assisted by a micro- or personal computer.
A FRAMEWORK FOR AUTOMATIC DFA SYSTEM-DEVELOPMENT
(1992-10-01)
LI, RK
;
HWANG, CL
;
交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
Design for assembly (DFA) evaluation has proved to be a systematic approach in determining how well a product is designed from an assembly point of view. Proposed here is a framework for automating DFA evaluation procedure, a key step in achieving a concurrent design environment. Five modules required for this development are: assembly sequence generation; assembly features extraction; assembly code and other necessary operations generation; data manipulation and computation; and re-design suggestion. Partial implementation (linking DFA evaluation procedure with a feature based CAD system) of the framework is also presented.
STRONG-FIELD EFFECTS ON THE ONE-DIMENSIONAL HYDROGEN-ATOM IN MOMENTUM SPACE
(1992-10-01)
PEN, UL
;
JIANG, TF
;
電子物理學系
;
Department of Electrophysics
The time evolution of the ground state of a one-dimensional hydrogen atom in the intense laser pulse is studied directly in momentum space. A finite matrix representation of operators is developed to solve nonperturbatively the time-dependent Schrodinger equation. We find that some numerical limitations in coordinate space of above-threshold ionization (ATI) can be overcome, and clear physical interpretations of the numerical data are possible. Both the ATI and harmonic-generation spectra are obtained. The correlations between these two multiphoton phenomena are discussed.
EFFECTS OF IMPURITY AND MAGNETIC-FIELD ON THE QUANTUM TRANSPORT IN A NARROW CONSTRICTION
(1992-10-01)
CHU, CS
;
交大名義發表
;
電子物理學系
;
National Chiao Tung University
;
Department of Electrophysics
The effects of impurities and magnetic fields on the quantized conductance G of a narrow constriction are studied. Both the cases when the impurity is inside and outside the effective width of the constriction are considered. We show that a strong attractive scatterer outside the effective width of the constriction can give rise to a dip structure in G. The occurrence of such a dip structure depends on the transverse location of the impurity. This is different from the effect of a weak scatterer inside the constriction which causes a dip structure in G only when the Fermi level is just below a transverse subband bottom. Our finding suggests a possible new scattering mechanism for quantum transport in narrow constriction systems. In addition, we demonstrate that in applying a perpendicular magnetic field, the backscattering of electrons from an impurity is suppressed, leading to better conductance quantization.
THE EFFECT OF SI AND CU ON THE INTERACTIONS BETWEEN AL FILMS AND A TIW BARRIER LAYER
(1992-10-01)
CHANG, PH
;
CHEN, HM
;
LIU, HY
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The effect of doping 1 wt % Si or 0.9 wt % Cu to Al films on the interactions between Al and TiW barrier layers at 450-degrees-C was studied. It was found that the first product is always Al12W, which forms at the Al/TiW interface, irrespective of the dopant addition. However, doping 1 wt % Si to Al film enhances the Al12W formation while doping 0.9 wt % Cu retards its formation. With excess tungsten in the system, Al12W would further react with W to form Al/W compounds with higher W content. In pure Al film, both the hexagonal Al5W phase and the monoclinic Al4W phase were detected to form after prolonged annealing at 450-degrees-C. The addition of 1 wt % Si or 0.9 wt % Cu to Al prohibits the formation of Al5W, thus only the Al4W phase was observed at the W/Al12W interface in the doped Al films.
APPLICATION OF MULTICRITERIA DECISION-MAKING TO THE EVALUATION OF NEW ENERGY SYSTEM-DEVELOPMENT IN TAIWAN
(1992-10-01)
TZENG, GH
;
SHIAU, TA
;
LIN, CY
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
The energy crisis in the 1970s and the recent rise in environmental protectionism have heightened interest in the introduction of new energy systems and the development of techniques to ensure the stability of the energy supply in Taiwan, where more than 90% of the supply is imported. In this study, a multicriteria evaluation method is employed to evaluate comprehensively the alternatives for new energy-system development. Energy technology, environmental impacts, sociology and economic factors were evaluated and development directions and strategy for future energy systems in Taiwan are proposed.
CORIOLIS ANTIPAIRING EFFECTS ON GROUND-STATE MOMENTS OF INERTIA
(1992-10-01)
LIN, L
;
TSAI, SF
;
電子物理學系
;
Department of Electrophysics
Anti-pairing effects of the Coriolis force are treated by applying the Bogoliubov transformation in a single-particle basis of the rotating reference system. The approach leads to state dependent anti-pairing forces. In the cranking model approximation, the calculated ground-state moments of inertia show improved agreements with experimental observations for the rare-earth nuclei.
DECODING METRICS FOR SLOW FREQUENCY-HOPPED DPSK SYSTEMS
(1992-10-01)
SU, YT
;
電信工程研究所
;
友訊交大聯合研發中心
;
Institute of Communications Engineering
;
D Link NCTU Joint Res Ctr
A variety of soft-decision decoding metrics for slow frequency-hopped, differential phase shift keyed spread-spectrum systems are studied. The computational cut-off rates in the presence of partial band noise jamming for these metrics are analysed. The usefulness of various degrees of side information, the effectiveness of limiting and quantisation when side information is not available, and the importance of a judicious choice of the quantisation step size are demonstrated. Monte-Carlo type simulations for the system encoded by Odenwalder's (7, 1/2) code are conducted, the resulting BERs reveal that close approximations can be attained by estimations calculated from a known closed-form formula.
THE EFFICIENT MEMORY-BASED VLSI ARRAY DESIGNS FOR DFT AND DCT
(1992-10-01)
GUO, JI
;
LIU, CM
;
JEN, CW
;
資訊工程學系
;
電子工程學系及電子研究所
In this paper, the efficient memory-based VLSI arrays and the accompanied new design approach for the discrete Fourier transform (DFT) and discrete cosine transform (DCT) are presented. The DFT and DCT are formulated as cyclic convolution forms and mapped into linear arrays which characterize small numbers of I/O channels and low I/O bandwidth. Since the multipliers consume much hardware area, the presented designs utilize small ROM's and adders to implement the multiplications, which is based on good data arrangements exploiting the number properties of the transform kernels. Moreover, the ROM size can be reduced effectively by arranging the data in our designs appropriately. Typically, to perform 1-D N-point DFT and DCT, the arrays need N X 2L words of ROM only. Compared to the conventional distributed arithmetic architectures which should require N X 2N words of ROM, much memory can be saved if N is greater than L, which occurs in most DFT applications. To summarize, the presented arrays outperform others in the architectural topology (local and regular connection), computing speeds, hardware complexity, the number of I/O channels, and I/O bandwidth. They take the advantages of both systolic arrays and the memory-based architectures.
SOLVING THE KP HIERARCHY BY GAUGE TRANSFORMATIONS
(1992-10-01)
CHAU, LL
;
SHAW, JC
;
YEN, HC
;
應用數學系
;
Department of Applied Mathematics
We show that it is convenient to use "gauge" transformations (sometimes called explicit Backlund transformations) to generate new solutions for the KP hierarchy. Two particular kinds of gauge transformation operators, constructed out of the initial wave functions, are of fundamental importance in this approach. Through such gauge transformations, a very simple formula for the tau-function is obtained, encompassing and unifying all kinds of existing solutions. The corresponding free fermion representation and Baker functions for the new tau function can also be constructed.
SYNTHESES AND CHARACTERIZATIONS OF ALLYL CELLULOSE AND GLYCIDYL CELLULOSE
(1992-10-01)
LIN, MS
;
HUANG, CS
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
Allyl cellulose was synthesized by reacting cellulose with allyl bromide in homogeneous LiCl/DMAc solution containing NaOH powder. The degree of substitution (DS) per anhydroglucose (AHG) unit was determined by titrating the allyl cellulose with bromine in chloroform solution, and an allyl DS of 2.80 was found. Glycidyl cellulose was then prepared by reacting this allyl cellulose with peracetic acid in methylene chloride at ambient temperature for 6 days. The measured reaction rate constant was 1.33 X 10(-3) min-1. The glycidyl cellulose thus obtained with a glycidyl DS of 2.58 was determined by titrating the product with perchloric acid in conjunction with tetrabutylammonium iodide. The 2.58 of glycidyl DS was also confirmed by H-1-NMR integration. Both allyl cellulose and glycidyl cellulose were analyzed and characterized with FTIR, H-1-NMR, C-13-NMR, TGA, and GPC. During epoxidation of allyl cellulose, possible side reaction leading to ester formation was evidenced from the continuous increase of nu(C=O) at 1735 cm-1 in FTIR analyses. In addition, a bimodal distribution and a decreased molecular weight for glycidyl cellulose were found from GPC data, which might suggest a possible chain scission at the cellulosic ether linkage.
A NEW ONE-PASS PARALLEL THINNING ALGORITHM FOR BINARY IMAGES
(1992-10-01)
WU, RY
;
TSAI, WH
;
資訊工程學系
;
Department of Computer Science
A new parallel thinning algorithm for binary images is proposed. This algorithm employs template matching to remove the edge points of an object shape in a binary image iteratively. Difficulty of terminating the thinning process without excessive erosion is solved without dividing an iteration into several passes. With a newly designed set of matching templates, the proposed algorithm obtains skeletons with the properties of perfectly 8-connected, noise-insensitive, and topologically equivalent to the original object shape without excessive erosion.