Browsing by Issue Date, starting with "1991-02-28"

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INVESTIGATION OF INDIUM DOPING AND INCORPORATION IN ALGAAS/GAAS DOUBLE-BARRIER RESONANT TUNNELING STRUCTURES
(1991-02-28)
WU, JS
;
CHANG, KH
;
LEE, CP
;
CHANG, CY
;
LIU, DG
In doping and incorporation in the barrier layers of AlGaAs/GaAs double-barrier resonant tunnelling structures (DBRTSs) have been studied. It was found that the peak-to-valley current ratio (PVCR) can be improved by the proper amount of In doping. This is attributed to the improvement in the quality of the AlGaAs barrier layers due to the high surface migration rate of In atoms that reduces group III vacancies. Also pseudomorphic In(x)(Al0.5Ga0.5)(1-x)As/GaAs (x = 0.12) strained-layer DBRTSs have been fabricated by incorporating a sufficient amount of In into the AlGaAs barrier layers. PVCRs as high as 27.5 at 77 K have been obtained. This is the first realisation of such DBRTSs with lattice-mismatched quaternary barrier layers.
EXTENDING TRANSMISSION DISTANCE OF HIGH-DENSITY WDM SYSTEMS USING POST TRANSMITTER FIBER RAMAN AMPLIFIERS
(1991-03-01)
KAO, MS
;
WU, JS
;
電信工程研究所
;
Institute of Communications Engineering
We investigate the behavior of the multichannel signals in a high-density WDM system with the consideration of stimulated Raman scattering. We provide a parameter to evaluate the depth of Raman crosstalk and analyze the transmission distance limitation imposed by Raman crosstalk. To extend the system transmission distance, a post transmitter fiber Raman amplifier is employed. The allocation of signal channels on the pump gain profile is discussed. We found that there exists an optimum pump power which results in a maximum amplifier gain. The example shows that the transmission distance limitation imposed by Raman crosstalk can be extended by 20 km for a 30-channel system with 0.25-dB/km fiber loss.
TURBULENT BOUNDARY-LAYER DIFFUSION FLAME - EFFECTS OF PROBABILITY DENSITY-FUNCTION
(1991-03-01)
CHEN, CH
;
LAN, CY
;
SHAN, DY
;
機械工程學系
;
Department of Mechanical Engineering
A turbulent diffusion flame adjacent to a solid fuel in a parallel airflow is studied analytically. The flow is assumed to be of boundary-layer type where the mean properties of flowfield are predicted by a low-Reynolds-number K-epsilon two-equation model. The chemical reaction is approximated as one-step and infinite-fast. The mean mass-fraction distribution in the boundary layer is described by probability density function (p.d.f.). Four kinds of p.d.f.s are used and they are beta, clipped Gaussian, double delta, and ten-point delta p.d.f.s respectively. The general features of each flame structure by applying corresponding p.d.f.s are quite similar. An overlap exists between fuel and oxidizer mean mass-fraction distributions. The maximal flame temperature is below the value of adiabatic one and its profile is rounded. The velocity, mixture fraction and its fluctuation, and total enthalpy are found to be almost invariant with the form of p.d.f.s. The mass fraction and temperature profiles appear nearly identical by the uses of beta and clipped Gaussian p.d.f.s. In application of double delta p.d.f., discontinuity shows up in these profiles. The modified ten-point delta p.d.f. has the maximum flame temperature due to its smallest overlap of YBAR(F) and YBAR(O) among these p.d.f.s.
ANALYSIS OF SEVERAL HIGH-ELECTRON-MOBILITY-TRANSISTOR STRUCTURES BY A SELF-CONSISTENT METHOD
(1991-03-01)
LIU, DG
;
CHIN, TC
;
LEE, CP
;
HWANG, HL
;
電控工程研究所
Three HEMT structures, the single heterostructure HEMT (SH-HEMT), the quantum well HEMT (QW-HEMT) and the delta-doped HEMT (delta-HEMT) were analyzed by solving the Schroedinger equation and Poisson equation self-consistently. The potential and the carrier distributions as well as the charge controlled by gate bias were calculated for different structural parameters. Parallel conduction in AlGaAs, which is severe for SH-HEMTs, is greatly reduced in QW-HEMT and delta-HEMT structures. The effect of layer parameters such as spacer layer thickness and quantum-well width on device performance has been studied. SH-HEMT and QW-HEMT have been fabricated for the confirmation of our analysis.
A NECESSARY AND SUFFICIENT CONDITION FOR THE EXISTENCE OF A COMPLETE STABLE MATCHING
(1991-03-01)
TAN, JJM
;
資訊工程學系
;
Department of Computer Science
A STUDY OF CORROSION FATIGUE BEHAVIOR OF ANODIZED AND UNANODIZED 2024-T3 ALUMINUM-ALLOY
(1991-03-01)
TU, GC
;
HWANG, RY
;
CHEN, IT
;
交大名義發表
;
機械工程學系
The corrosion fatigue (CF) behaviour, under constant deflection bending conditions with a pulsating tension stress form, of 2024-T3 aluminium alloy, unanodized and anodized to form a thick porous film, in 3.5% NaCl solution has been investigated. It was found that E(corr) varies very little until specimen fracture under low frequency CF conditions, whereas E(corr) drops rapidly when approaching the later fracturing stage of the CF process under high-frequency conditions for unanodized specimens. However, a slow drop in E(corr) was detected from the commencement of the CF process, and lasted up to a much more rapid drop at a later fracturing stage for the anodized specimen. This behaviour presumably can be explained by the cracking of the anodic film and the theory of imperfect recovery of the surface film. It is suggested that the E(corr) monitoring technique may be useful for determining the remnant CF life for existing structural parts of this alloy or other aluminium alloys regardless of whether or not they are anodized. Furthermore, the T3 temper provides a microstructure which may retard main-crack formation and penetration in the CF process of the anodized alloy, thus mitigating partly the negative effect of the readily crackable anodic film.
CENTRALIZED EFFECT ON EXPECTED COSTS IN A MULTILOCATION NEWSBOY PROBLEM
(1991-03-01)
CHANG, PL
;
LIN, CT
;
管理科學系
;
Department of Management Science
This is a single-period single-product inventory model with several individual sources of demand. It is a multi-location problem with an opportunity for centralization. The holding and penalty cost functions, at each location, are assumed to be linear and identical. Two types of inventory system are considered in this paper: The decentralized system and the centralized system. The decentralized system is a system in which a separate inventory is kept to satisfy the demand at each source of demand and there is no reinforcement between locations; i.e., the surplus supplied location is not allowed to supply the deficient supplied location. Therefore, the total expected cost of the decentralized system is the sum of the expected cost of individual locations, as the holding cost or penalty cost of each location depends only on its own inventory level and is unrelated to any other location's inventory level. The centralized system is a system in which the surplus location is allowed to supplement the deficient one by transportation. Therefore, the holding cost or penalty cost is calculated by the net surplus or net deficient after the reinforcement. The total expected cost of the centralized system should therefore include the expected holding cost, the expected penalty cost and the expected transportation cost. Let hBAR > 0,pBAR > 0 and tBAR greater-than-or-equal-to 0 be the unit holding cost, the unit penalty cost and the unit transportation cost, respectively. This paper demonstrates that, for any probability distribution of a location's demand, the following two properties are always true: (1) tBAR < hBAR+pBAR if and only if the total expected cost in a decentralized system exceeds those in a centralized system. (2) For all i, j, i not-equal j, p(ij), the coefficient of correlation between the i-th location's demand and the j-th location's demand, is equal to 1, then for any tBAR, the total expected cost in a decentralized system is equal to those in a centralized system.
ENHANCED OXYGEN REACTIVE ION ETCHING RESISTANCE OF DIAZONAPHTHOQUINONE-POLY (FORMYLOXYSTYRENE) RESIST SYSTEM BY PHOTOACID CATALYZED PHOTO-FRIES REARRANGEMENT AND POTASSIUM-ION TREATMENT IN AQUEOUS-SOLUTION
(1991-03-01)
LOONG, WA
;
SU, AN
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
This paper presents a new process for the enhancement of oxygen reactive ion etching (RIE) resistance of a single-layer, deep UV resist system by selective incorporating of potassium ion with resist image in aqueous solution after exposure. A resist system of diazonaphthoquinone (DAQ) and poly(p-formyloxystyrene) (PFS) mixed with catalytic amount of triphenylsulfonium hexafluoroarsenate as a photoacid is exposed to deep UV. Photoacid catalyzes the photo-Fries rearrangement of PFS to form poly(p-hydroxystyrene) (PHS); DAQ rearranges to form indene carboxylic acid and grafts into PHS via S-O bond formation. A latent image is formed by selective reaction of carboxylic group with C5H11COOK in aqueous solution in exposed area which is resistant to oxygen RIE. There are no such reactions in unexposed area. The dry developed negative-tone patterns by oxygen RIE are obtained.
TEMPERATURE CYCLING EFFECTS BETWEEN SN/PB SOLDER AND THICK-FILM PD/AG CONDUCTOR METALLIZATION
(1991-03-01)
CHIOU, BS
;
LIU, KC
;
DUH, JG
;
PALANISAMY, PS
;
電控工程研究所
Thermal cycling effects on solder joint between thick film mixed bonded conductor and Sn/Pb solder are investigated. Microstructural evolution of the interfacial morphology, elemental, and phase distribution are probed with the aid of electron microscopy and x-ray diffraction. Microstructural analysis reveals the formation of intermetallic compounds Pd3Sn, Pd2Sn, Pd3Sn2, PdSn, Pd3Pb, Ag5Sn, and Ag3Sn, after thermal cycles from -55 to + 125-degrees-C. A transverse crack is observed across the joint from the conductor/substrate interface to the conductor/solder interface, which results in the failure of the joint. The microstructural analysis and stress analysis reveal that the transverse crack is initiated by the microcracks at the glass penetrated region of the substrate and propagates under a tensile stress due to the solder shrinkage. An appropriate joint geometry and a materials system with good interface strength and with negligible thermal expansion mismatch are important in the enhancement of the life time for the solder joints in thick film microelectronics.
DEMOCRATIZATION AND INSTITUTIONALIZATION - PROBLEMS, PROSPECTS, AND POLICY IMPLICATIONS OF POLITICAL-DEVELOPMENT IN THE REPUBLIC OF CHINA ON TAIWAN
(1991-03-01)
YUNG, W
;
交大名義發表
;
National Chiao Tung University
管管作品兩首
(1991-03-01)
管管
荷
(1991-03-01)
管管
荷
(1991-03-01)
管管
KEV ION-BEAM-EXPOSED POLY(METHYLISOPROPENYLKETONE) AND POLY(PHENYLISOPROPENYLKETONE)
(1991-03-01)
LOONG, WA
;
PENG, NT
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
The exposure characteristics of poly(methylisopropenylketone) (PMIPK) and poly(phenylisopropenylketone) (PPIPK) exposed to 40 and 80 keV H+ and B+ ion beams have been studied. It is found that the electron-rich phenyl group in PPIPK has increased stopping power for the bigger B+ ion, but not for the smaller H+ ion. For the same reason, the main chain scissioning of PPIPK is slower than that of PMIPK when they are exposed to B+, but not to H+, under the same exposure conditions. Linear relationships are found with simulation parameter A which stands for exposure efficiency of the ion beam as a function of exposure doses (keV x ion fluence) for a specific ion-exposed polymer within the used energy range.
COVARIANCE ANALYSIS ALGORITHM FOR INTERCONNECTED SYSTEMS
(1991-03-01)
CURLEY, RD
;
CHENG, VHL
;
LIN, CA
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We present in this paper a covariance analysis algorithm for propagation of signal statistics in arbitrarily interconnected nonlinear hybrid systems, applied to six-degree-of-freedom systems specifically in our work. The algorithm uses statistical linearization theory to linearize the nonlinear subsystems, and the resulting linearized subsystems are considered in the original interconnection framework for propagation of the signal statistics. We shall refer to some nonlinearities commonly encountered in six-degree-of-freedom space-vehicle models to illustrate the limitations of this method, along with problems not encountered in standard deterministic simulation analysis. Moreover, we shall exhibit the performance of the algorithm numerically by comparing results from such techniques to results from Monte-Carlo analysis results, both applied to a simple two-dimensional space-intercept problem.
EVIDENCE OF STRAIN-INDUCED MARTENSITIC-TRANSFORMATION IN FE-MN-AL AUSTENITIC ALLOY-STEELS AT ROOM-TEMPERATURE
(1991-03-01)
CHEN, FC
;
LI, P
;
CHU, SL
;
CHOU, CP
;
機械工程學系
DEEP PHASE-MODULATION APPROACH TO AN OPEN-LOOP FIBER OPTIC GYROSCOPE
(1991-03-01)
CHIEN, PY
;
PAN, CL
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A new approach to an open-loop, all-fiber gyroscope with wide dynamic range and linear scale factor is described. For signal processing, the Sagnac phase lift is converted into a phase shift in the low-frequency electrical signal by using a deep sinusoidal phase-modulation waveform followed by gate-switching. With the duty cycle of the gating signal selected to be in the range between 20 and 70%, the scale factor is stable with respect to change in the amplitude of the phase modulation signal by as much as 15%. The basic principle of this technique and experimental results are reported.
SYNTHESIS AND SUPERCONDUCTING PROPERTIES OF TL-BA-CA-CU-O FILMS
(1991-03-01)
LIOU, SH
;
CHAN, VK
;
FOONG, F
;
LEE, WY
;
GOU, YS
The TI-Ba-Ca-Cu-O superconducting films were synthesized by sputtering either from a single target or from two oxide targets in a symmetric configuration. Films with zero resistance T(c) of up to 122 K were obtained after various post annealing treatment at 870 - 950-degrees-C under oxygen atmosphere. We have studied morphology, structure, magnetic and superconducting properties of these films. Films prepared by two different sputtering techniques have similar results which depend mostly on the film compositions and their annealing conditions. We found that the induced magnetic flux in the film decreases rapidly with increasing temperature, indicating the weak flux pinning.
管管作品兩首
(1991-03-01)
管管
A TEMPORALLY RESOLVED POSITION SENSING DEVICE FOR AUTOFOCUSING
(1991-03-01)
SHIE, JS
;
CHANG, GD
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A position-sensing method for autofocus purpose is demonstrated, based on the triangular ranging principle applied to a photoconductive Haynes-Shockley device. This method provides a linear variation of the minority-carrier transit time in the sensor with respect to the inverse of the object distance, or to the image distance to be adjusted from the focal point. Hence it can provide a convenient autofocusing control with a fully digital signal processing circuit. The principle of the autofocus triangular ranging is justified, and its resolution is analyzed with a p-type silicon photoconductor. The result shows that our method indeed can provide a high resolution and practically low cost autofocusing device for the camera industry.