Browsing by Issue Date, starting with "1994-07-01"

Now showing 1 - 20 of 88241

CHARACTERISTICS OF DIELECTRIC-LINE-LOADED CONDUCTOR-BACKED SLOTLINE (CBS)
(1994-07-01)
HUANG, JW
;
TZUANG, CKC
;
交大名義發表
;
傳播研究所
;
National Chiao Tung University
The mode-coupling phenomenon prevents the conventional shielded conductor-backed slotline (CBS) from broadband applications. This paper proposes a modified CBS by adding a dielectric line of higher dielectric constant on the top of the dot region to circumvent the mode-coupling problem. The dispersion characteristics of the resultant dielectric line-loaded CBS are studied by using the full-wave space-domain Green's impedance. function approach. The theoretic results show that the particular modified CBS significantly reduces mode-coupling phenomenon and is suitable for broadband applications. Furthermore, it is possible to adjust the values of the propagation constant and the characteristic impedance by changing the thickness of the dielectric line on top of the slot region. Finally, the design curves for the dielectric line-loaded CBS are provided for potential applications.
SIMULTANEOUS NULLING FOR MONOPULSE ARRAY WITH PARTIALLY ADAPTIVE WEIGHTS
(1994-07-01)
LEE, TS
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
;
Institute of Communications Engineering
A new simple method is described for synthesizing low-sidelobe sum and difference patterns with partially adaptive weights. By partially adaptive, we mean that only part of the weights are adapted for simultaneous nulling. These adaptive weights are shared by the sum and difference channels, leading to a significant reduction in the number of variable attenuators/phase shifters used, as compared to the fully adaptive implementation. An objective function is derived that yields different configurations of the shared adaptive weights. Numerical examples are presented to ascertain the efficacy of the new method for both point and extended interference.
EFFECT OF CROSS-PHASE MODULATION ON OPTICAL-PHASE CONJUGATION IN DISPERSION-SHIFTED FIBER
(1994-07-01)
WEN, SF
;
CHI, S
;
CHANG, TC
;
光電工程學系
;
Department of Photonics
The temporal effect of optical phase conjugation in dispersion-shifted fiber is studied numerically. Frequency chirping is induced in the conjugate pulse by the signal pulse and the pump wave through cross-phase modulation, which increases with the signal power and may distort the pulse shape when the conjugate pulse propagates in the standard fiber. It is also shown that, when the signal power is low, the optical phase conjugation is nearly ideal.
REDUCTION OF STRINGY SCATTERING-AMPLITUDES THROUGH MASSIVE WARD IDENTITIES
(1994-07-01)
LEE, JC
;
交大名義發表
;
電子物理學系
;
National Chiao Tung University
;
Department of Electrophysics
It is shown that the scattering amplitudes of some degenerate massive string states can be expressed in terms of that of higher spin states at the same mass level. This phenomenon is discussed from sigma-model point of view and demonstrated explicitly by using massive Ward identities generated by zero-norm states at D = 26. The subtlety of the scalar propagating state is briefly pointed out. We also compare our on-shell gauge symmetry derived from sigma-model with off-shell gauge symmetry of covariant string field theo
FLUX-FLOW OF ABRIKOSOV VORTICES IN TYPE-II SUPERCONDUCTORS
(1994-07-01)
CHEN, JL
;
YANG, TJ
;
電子物理學系
;
光電工程研究所
;
Department of Electrophysics
The theory of flux flow developed by Bardeen and Stephen (BS) is modified and extended to the high-field case. The Clem model and Wigner-Seitz circle-cell approximation for vortices are used in our approach. The distinct boundary of the normal core of a vortex in BS theory is removed and treated naturally. Several interesting results come out as a consequence. The Lorentz force is determined by the normal current rather than the supercurrent. But the supercurrent can sustain the magnetic-field distribution of flux quanta. From energy dissipation considerations, the Lorentz force is equal to viscosity force automatically without assumption as made in BS theory. An expression for the viscosity is also obtained.
DEPOSITION OF MOLYBDENUM CARBONITRIDE THIN-FILMS FROM MO(NBUT)2(NHBUT)2
(1994-07-01)
CHIU, HT
;
HO, WY
;
CHUANG, SH
;
交大名義發表
;
應用化學系
Mo(NBut)2(NHBut)2 is used as a single-source precursor to deposit thin films of cubic phase molybdenum carbonitride, MoC(x)N(y), (x: 0.2-0.55, y: 0.1-0.47), by chemical vapor deposition on silicon substrates. in general, the C/Mo ratios increased from 0.2 to 0.55 and the N/Mo ratios decreased from 0.47 to 0.1 with increasing the temperature of deposition from 773 to 923 K. Based on the elemental composition and the composition of the gas phase products, it is proposed that the carbon atoms were incorporated through beta-methyl activation of the ligands.
PERFORMANCE OF FAST FH MFSK SIGNALS IN JAMMED BINARY CHANNELS
(1994-07-01)
SU, YT
;
CHANG, RC
;
電信工程研究所
;
友訊交大聯合研發中心
;
Institute of Communications Engineering
Soft-decision decoded performance of fast frequency-hopped (FH) M-ary FSK signals over partial band noise jammed binary channels is studied. The effects of metrics conversion, quantization, and the presence of regenerative nodes on the system's cutoff rate performance are investigated. It is found that the conversion from an M-ary metric to a binary one suffers only negligible degradations. For communication links without regenerative nodes, as expected, the infinite-bit soft-decision is the optimal metric, followed by finite-bit soft decision and then hard-decision. For those with regenerative nodes, however, the infinite-bit soft-decision is outperformed by the hard-decision, but the finite-bit soft-decision decoder still keeps its edge over the latter. The issue concerning the order of metric conversion and diversity combining is also analyzed. Numerical results indicate that the conclusion obtained by an earlier simulation report addressing a similar design alternative in fading channels is valid for jammed binary channels, as well. That is, the precombining metric conversion technique gives up only minor performance degradations when compared to the more sophisticated postcombining metric conversion technique.
MULTIOBJECTIVE DECISION-MAKING APPROACH TO ENERGY SUPPLY MIX DECISIONS IN TAIWAN
(1994-07-01)
TZENG, GH
;
SHIAU, TA
;
TENG, JY
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
This article proposes an integrated multiobjective decision-making (MODM) model to deal with energy supply mix problems in Taiwan based on its characteristics. The analytical framework integrates multiobjective programming (MOP), multicriteria decision making (MCDM), and group decision making (GDM) methods and considers decision dependencies existing in the time horizon. The integrated model has the advantages of flexibility, reasonableness, and robustness. The analyzed outputs, including alternatives, the preferred solution, and the best compromise solution, are provided as a basis for decision making.
A QUARTER-WAVE PLATE USING SUBSTRATE-MODE HOLOGRAMS
(1994-07-01)
SU, DC
;
YOO, JC
;
TSAI, YK
;
HUANG, YT
;
電子工程學系及電子研究所
Based on the phase shifts due to the total internal reflection and the grating diffraction, a new type of quarter-wave plate using substrate-mode holograms is presented. A sample of this device was fabricated to demonstrate its function.
A MULTIECHELON EVALUATION FRAMEWORK FOR CIM SYSTEMS-DESIGN
(1994-07-01)
LIU, MC
;
TSAI, TJ
;
LIANG, SK
;
LI, RK
;
工業工程與管理學系
Implementing a computed integrated manufacturing (CIM) system design involves major capita] investment which must take into consideration state-of-the-art technologies and management strategies. This multi-echelon evaluation framework employs strategic planning, conceptual design, risk analysis, sensitivity analysis, simulation and the analytical hierarchical process to evaluate the CIM system design. This approach is characterized by flexibility and assessability of the iterative evaluation cycles, subjective utility functions of decision makers, and simulation for risk analysis at different stages of the evaluation process. It provides management with a decision support tool when considering CIM implementation. A case study is presented to demonstrate this multi-echelon evaluation framework for CIM systems design.
RAMAN CHARACTERIZATIONS OF RUTHENIUM DICHALCOGENIDES
(1994-07-01)
HWANG, ST
;
HUANG, JK
;
HUANG, YS
;
電子物理學系
;
Department of Electrophysics
Raman scattering of single-crystal RuTe2 has been carried out with good frequency resolution and wide wavelength coverage. In this article, our results are presented and compared with those for other ruthenium dichalcogenides (RuSe2, and RuS2) reported previously. We found a good linear relationship between all Raman shifts and the reciprocal chalcogen mass. We also observed resonant scattering related to inter-electronic-band transitions.
NEW LARGE-ANGLE TILT IMPLANTED DRAIN STRUCTURE - SURFACE COUNTER-DOPED-LIGHTLY DOPED DRAIN FOR HIGH HOT-CARRIER RELIABILITY
(1994-07-01)
CHOU, JW
;
CHANG, CY
;
HUANG, C
;
HO, LT
;
KO, J
A new surface counterdoped-lightly doped drain (SCD-LDD) structure with large angle tilt (LAT) implantation is proposed in this study. This structure introduces an additional larger tilt angle and lower-energy BF2 implant after the n- implant, which counterdopes the n- surface concentration to achieve a gate/n- fully overlapped, buried and sloped n- region inside the gate edge. As a result, the lateral electric fields inside the gate edge are reduced and pushed deeper into the substrate. In addition to a reduction in substrate current, this profile also suppresses hot carrier injection by driving the current away from the surface and the maximum electric field; then it shifts the avalanche region further into the bulk Si. This consequently produces a more effective enhancement of hot carrier reliability than that of conventional LDD's and controlled large-angle-tilt implanted drains (LATID's) for submicron VLSI circuits under 5 V operation. In conclusion, this SCD-LDD provides one more degree of freedom in optimizing the n- region doping profiles as a new LATID structure.
SYNTHESIS AND X-RAY-DIFFRACTION OF FERROELECTRIC LIQUID-CRYSTALLINE POLYSILOXANES CONTAINING 4'-(2-CHLORO-3-METHYL-PENTANOYLOXY)-4-ALKANYLOXYBIPHENYL SIDE-GROUPS
(1994-07-01)
HSIUE, GH
;
HSIEH, PJ
;
WU, SL
;
HSU, CS
;
應用化學系
The synthesis and characterization of side-chain liquid crystalline polysiloxanes containing (2S,3S)-4'-(2-chloro-3-methylpentanoyloxy)-4-alkanyloxybiphenyl side groups are presented. All the obtained polymers exhibit smectic mesomorphism. Those polymers containing a spacer length longer than 8 methylene units reveal respectively enantiotropic S(A), S(C)* and S(B) phases. The result demonstrates that the tendency toward the S(C)* phase increases with increasing the spacer length.
SINGLE DROPLET COMBUSTION IN A GRAVITATIONAL ENVIRONMENT
(1994-07-01)
HUANG, LW
;
CHEN, CH
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
A theoretical analysis is developed to study the combustion characteristics of a fuel droplet in a gravitational field. The normalized governing system consists of the complete conservation equations in r-z coordinates and includes finite-rate global kinetics. The Clausius-Clapeyron law is applied at the liquid-vapor interface to describe the evaporation process. A modified body-fitted grid generation technique is used to handle irregular boundaries. The effects of changing the droplet diameter (dBAR) and the gravity level (gBAR) are investigated. Under the variation of droplet diameter, flame structures, including isotherms, flame shape, velocity vector field, and mass burning rate are studied in detail. The predicted results exhibit good agreement with experimental data. When the gravity level increases, the computed results show that the flame shape is sensitive to variation in gravity. A simple correlation, mBAR = m0BAR [1 + const. (alpha/gBAR)0.52], is found. Within the elevated gravity domain of experiment, the computed data agree well with measurements obtained by Okajima and Kumagai [10].
A FINITE-ELEMENT ANALYSIS OF BENDING DIELECTRIC WAVE-GUIDES WITH REFLECTION WALLS
(1994-07-01)
CHUNG, SJ
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交大名義發表
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電信工程研究所
;
National Chiao Tung University
;
Institute of Communications Engineering
The finite-element method together with the Green's-function technique is employed to tackle the scattering problem of bending dielectric waveguides with reflection walls. The influences of the frequency, the ratio of waveguide widths, and the length of the reflection wall on the scattering characteristics of 90-degrees and 120-degrees bends are presented. (C) 1994 John Wiley & Sons, Inc.
FAULT-LOCATING AND SUPERVISORY TECHNIQUE FOR MULTISTAGED BRANCHED OPTICAL NETWORKS
(1994-07-01)
CHEN, YK
;
CHI, SE
;
光電工程學系
;
Department of Photonics
A fault-locating and supervisory technique for large multistage branched optical fiber networks is proposed. The requirement of ultra-wide dynamic range of an optical time-domain reflectometer (OTDR) to diagnose the network can be tremendously relaxed. Not only can the failure of optical splitter itself be monitored, but also any faults of the fiber links whether before, after, or between optical splitters can be located. The feasibility of this technique was experimentally demonstrated in a 128-branched network using an erbium-doped fiber-amplifier-enhanced OTDR.
IS CIRCULARITY PROBLEM FOR ATTRIBUTE GRAMMARS EXPONENTIAL-TIME COMPLETE
(1994-07-01)
WU, PC
;
WANG, FJ
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資訊科學與工程研究所
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Institute of Computer Science and Engineering
A UNIFIED APPROACH TO A CHARACTERIZATION OF GRASSMANN GRAPHS AND BILINEAR-FORMS GRAPHS
(1994-07-01)
FU, TS
;
HUANG, TY
;
應用數學系
;
Department of Applied Mathematics
ALGORITHMS FOR THE WINDY POSTMAN PROBLEM
(1994-07-01)
PEARN, WL
;
LI, ML
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工業工程與管理學系
;
Department of Industrial Engineering and Management
The Windy Postman Problem (WPP), is an interesting generalization of the classical Chinese Postman Problem (CPP), which has many real-world applications. The WPP has been shown to be NP-complete; therefore, it is difficult to solve the problem exactly. For this reason, heuristic solution procedures have been proposed to solve the problem approximately. In this paper, we first review the existing solution procedures, then introduce two new algorithms to solve the WPP near-optimally. Computational results show that the new algorithms outperform the existing solution procedures on some special class of networks.
INFLUENCE OF OXYGEN ON THE PERFORMANCE OF GAAS/ALGAAS QUANTUM-WELL INFRARED PHOTODETECTORS
(1994-07-01)
TSAI, KL
;
LEE, CP
;
CHANG, KH
;
CHEN, HR
;
TSANG, JS
The influence of oxygen on the performance of GaAs/AlGaAs quantum well infrared photodetectors (QWIP) has been studied. Photoluminescence and secondary ion mass spectroscopy were used to examine the relationship between the quality of AlGaAs and the oxygen content that were then correlated to the performance of QWIPs. It was found that oxygen is the dominant impurity in the GaAs/AlGaAs superlattice. Because oxygen atoms behave likes electron traps, which effectively reduce the carrier concentration in the material, both of the responsivity and the dark current of QWIP are reduced. The detectivities of QWIPs with lower oxygen concentrations are better than those with higher oxygen concentrations.