Browsing by Issue Date, starting with "1994-04-10"

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POLARIZATION-SELECTIVE VOLUME HOLOGRAMS - GENERAL DESIGN
(1994-04-10)
HUANG, YT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
General design of polarization-selective volume holograms is discussed in detail. The required diffraction angles for these highly polarization-selective elements are calculated. An effective index-modulation parameter is defined and used to calculate the required index-modulation value at any specified operating wavelength. Design examples of operating wavelengths at 780, 830, 1050, 1300, and 1550 nm are given. Highly polarization-selective substrate-mode grating pairs for 780-nm operation were fabricated to verify the idea. These elements are suitable for applications in optical switching networks and magneto-optic data storage systems.
STRUCTURES AND ANTIFERROMAGNETIC PR ORDERING MECHANISM OF TL(BA2-XSRX)PRCU2O7-Y COMPOUNDS BY RIETVELD ANALYSIS
(1994-04-10)
FUN, HK
;
YANG, P
;
LAI, CC
;
KU, HC
;
LEE, TJ
The crystalline structures of Tl(Ba2-xSrx)PrCu2O7-x (x=0, 0.4, 0.8, 1.0, 1.2, 1.6, 2) were obtained at room temperature (300 K) and low temperature (100 K) from X-ray powder diffraction with Cu Kalpha radiation using Rietveld analysis. Tl(Ba2-xSrx)PrCu2O7-x has an isotypical structure with TlBa2CaCu2O7(1212) at 300 and 100 K, i.e., the tetragonal system, space group P4/mmm, Z=1. The relationships between the Pr-O(1) bond lengths and the O(1)-Pr-O(1) bond angles with the antiferromagnetic ordering temperature T(n) (Neel temperature) are discussed. The mechanism of the decrease in the antiferromagnetic ordering temperature T(n) as well as the nonsuperconductivity of this system are explained using the Pr(4f) and O(2p) orbital hybridization and the Pr-O(1) bond lengths. The suggested mechanism of Pr-Pr coupling (interplanar Pr-Pr distance) for the Pr ordering by a previous study is inconsistent with our experimental results.
OBSERVATION OF MODE SELECTION IN A RADIALLY ANISOTROPIC CYLINDRICAL WAVE-GUIDE WITH LIQUID-CRYSTAL CLADDING
(1994-04-11)
CHEN, SH
;
CHEN, TJ
;
交大名義發表
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光電工程學系
;
National Chiao Tung University
Observation of mode selection in an optical fiber with nematic liquid-crystal cladding is reported. The TE01 mode is guided, while the TM01 mode leaks out. This behavior is achieved by radially oriented liquid-crystal directors in the cladding of an optical fiber with isotropic core. A theory which quantitatively accounts for the results is given.
UNDOING OF SOLITON INTERACTION BY OPTICAL-PHASE CONJUGATION
(1994-04-14)
WEN, S
;
CHI, S
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光電工程學系
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Department of Photonics
The undoing of soliton interaction by optical phase conjugation in the presence of third-order dispersion and fibre loss which is compensated for by optical amplifiers are studied. If the conjugator is applied before there are significant changes in the pulse shapes, the soliton interaction can be undone well.
DISJOINT ODD INTEGER SUBSETS HAVING A CONSTANT ODD SUM
(1994-04-15)
FU, HL
;
HU, WH
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應用數學系
;
Department of Applied Mathematics
We prove that for positive k, n and m, the set {1, 3,...,2n - 1} of odd integers contains k disjoint subsets having a constant odd sum m if and only if 9(k - 1) less-than-or-equal-to m less-than-or-equal-to 2n - 1, or 9k less-than-or-equal-to m less-than-or-equal-to n2/k and n2 - mk not-equal 2.
MESSAGE COMPLEXITY OF HIERARCHICAL QUORUM CONSENSUS ALGORITHM
(1994-04-22)
CHANG, HK
;
YUAN, SM
;
資訊工程學系
;
Department of Computer Science
The hierarchical quorum consensus (HQC) algorithm, which is a generalization of the standard quorum consensus algorithm for managing replicated data, can reduce the quorum size to N0.63. This paper analyzes the message complexity of HQC. Moreover, an asymptotic analysis on the ratio of the message complexity to the quorum size is presented. It is shown that the ratio converges to a constant.
A FUZZY MULTICRITERIA DECISION-MAKING METHOD FOR TECHNOLOGY-TRANSFER STRATEGY SELECTION IN BIOTECHNOLOGY
(1994-04-25)
CHANG, PL
;
CHEN, YC
;
管理科學系
;
Department of Management Science
This paper discusses the potential application of fuzzy set theory to technology transfer strategy selection in the area of biotechnology management. An algorithm for technology transfer strategy selection is proposed. The algorithm is based on the concepts of fuzzy set theory and the hierarchical structure analysis. The linguistic variables and fuzzy numbers are used to aggregate the decision makers' subjective assessment about criteria weightings and appropriateness of alternative transfer strategies versus selection criteria to obtain the final scores called fuzzy appropriateness indices. We also propose a revised method for ranking fuzzy numbers with index of optimism which was proposed by Kim and Park. Our revised method is based on the stage of data input for computing the total index of optimism in multi-person decision making problem, instead of giving the index of optimism independently by a decision maker on the stage of information output. This new look at the index of optimism reflects the pooled risk-bearing attitude of multi-judge. The index of optimism is determined by the evaluation data conveyed by the decision makers at the beginning of the data input stage. Finally, we use the revised method to rank the fuzzy appropriateness indices for choosing the best technology transfer strategy.
EFFECTS OF ZRO2 ON THE TEXTURING AND PROPERTIES OF MELT-PROCESSED Y1BA2CU3O7-DELTA
(1994-04-25)
JUANG, JY
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WU, CL
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WANG, SJ
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CHU, ML
;
WU, KH
The addition of ZrO2 is found to be very effective as the nucleation sites to promote the oriented growth of Y1Ba2Cu3O7-delta (YBCO) during peritectic solidification. Extended regions of well-textured YBCO grains with superior superconducting properties of the YBCO bulk are readily obtained by a single-step melt process at much lower process temperatures. At 77 K, the platelike Josephson weak-link behaviors observed in pure melt-processed YBCO have been effectively eliminated, indicating that the coherency between the spherulitic superconducting YBCO grains may have been greatly improved by ZrO2 additions.
魯迅的「藥」
(1994-04-27)
管管
SPONTANEOUSLY BROKEN SYMMETRY IN STRING THEORY
(1994-04-28)
LEE, JC
;
物理研究所
;
Institute of Physics
By using zero-norm states in the spectrum, we explicitly demonstrate the existence of an infinite number of high energy symmetry structures of the closed bosonic string theory. Each symmetry transformation (except those generated by massless zero-norm states) relates infinite particles with different masses, thus they are broken spontaneously at the Planck scale as previously conjectured by Gross and Evans and Ovrut. As an application, the results of Das and Sathiapalan which claim the sigma-model is nonperturbatively nonrenormalizable were reproduced from a stringy symmetry argument point of view.
SYNTHESIS AND THERMAL-BEHAVIOR OF SIDE-CHAIN LIQUID-CRYSTALLINE POLYMETHACRYLATES CONTAINING TOLANE-BASED MESOGENIC SIDE-GROUPS
(1994-04-30)
HSIEH, CJ
;
WU, SH
;
HSIUE, GH
;
HSU, CS
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應用化學系
The synthesis and characterization of nine polymethacrylates containing 4-alkoxy-4'-tri-fluoromethyltolane, 4-alkoxy-4'-cyanotolane, and 4-alkoxy-4'-nitrotolane side groups were described in this study. The phase behavior of the prepared monomers and polymers was characterized by differential scanning calorimetry, optical polarizing microscopy, and x-ray diffraction. All of the obtained monomers exhibit no mesophase, while most of the synthesized polymers reveal enantiotropic mesomorphism. The polymethacrylate containing 4-propanyloxy-4'-nitrotolane side groups was the only one which shows no mesomorphic behavior. Both the spacer length and the nature of terminal groups have profound influence on the phase transition temperatures and thermal stability of the mesophase. The polymers with longer spacers tend to form a more ordered mesophase with a wider temperature range. Among three polymers with the same spacer length, the polymer with a trifluoromethyl terminal end group is inclined to form a more ordered mesophase than the other two polymers. No side chain crystallization occurred for all obtained polymers. (C) 1994 John Wiley & Sons, Inc.
THE EFFECTS OF FLUORINE PASSIVATION ON POLYSILICON THIN-FILM TRANSISTORS
(1994-05-01)
CHERN, HN
;
LEE, CL
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LEI, TF
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The fluorine implantation on polysilicon was found to improve the characteristics of polysilicon thin-film transistors (TFT's). The fluorine passivates the trap states within the polysilicon channel. As compared with the H-2-plasma passivation, the fluorine implantation passivates more uniformly both the band tail-states and midgap deep-state, while the H-2-plasma treatment is more effective to passivate deep states than tail states. A fluorine-implanted device can be further improved its performance if an H-2-plasma treatment is applied. In contrast to the H-2-plasma passivation, the fluorine passivation improves the device hot-carrier immunity. Combining the fluorine passivation and H-2-plasma passivation, a high performance TFT with a high hot-carrier immunity can be obtained.
SUPPRESSION OF THE BORON PENETRATION INDUCED SI/SIO2 INTERFACE DEGRADATION BY USING A STACKED-AMORPHOUS-SILICON FILM AS THE GATE STRUCTURE FOR PMOSFET
(1994-05-01)
WU, SL
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LEE, CL
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LEI, TF
;
CHEN, JF
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CHEN, LJ
This letter reports that the boron penetration through the thin gate oxide into the Si substrate does not only cause a large threshold voltage shift but also induces a large degradation in the Si/SiO2 interface. An atomically flat Si/SiO2 interface can be easily obtained by using a stacked-amorphous-silicon (SAS) film as the gate structure for p+ poly-Si gate MOS devices even the annealing temperature is as high as 1000-degrees-C.
BUOYANCY-INDUCED FLOW TRANSITION IN MIXED CONVECTIVE FLOW OF AIR THROUGH A BOTTOM HEATED HORIZONTAL RECTANGULAR DUCT
(1994-05-01)
HUANG, CC
;
LIN, TF
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
A detailed numerical simulation was carried out to study the buoyancy induced flow transition in a mixed convective flow of air through a bottom heated horizontal rectangular duct. The unsteady three-dimensional Navier-Stokes and energy equations were directly solved by a higher order finite difference numerical scheme without using any turbulence modeling. Results were particularly presented for Re = 500 and A = 2 covering a wide range of Gr/Re2 from steady laminar longitudinal vortex now to unsteady chaotic flow. The results indicate that the increasing buoyancy causes the steady laminar flow for Gr/Re2 < 4 to become a periodic laminar flow for 4 less-than-or-equal-to Gr/Re2 < 19, then to a quasiperiodic flow for 19 less-than-or-equal-to Gr/Re2 < 25 and finally to a chaotic flow in the downstream for 25 < Gr/Re2 less-than-or-equal-to 40. Thus, the buoyancy induced laminar to turbulent flow transition follows the Ruelle-Taken route. An empirical equation was proposed to correlate the locations for Hopf bifurcation.
A NEW METHOD FOR HANDLING MULTICRITERIA FUZZY DECISION-MAKING PROBLEMS
(1994-05-01)
CHEN, SM
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
;
Department of Computer Science
This paper presents a new method for handling multicriteria fuzzy decision-making problems, in which the characteristics of the alternatives are represented by interval-valued fuzzy sets, and some techniques are developed to calculate the degree of similarity between interval-valued fuzzy sets. The proposed method is more flexible than the one we presented earlier (Chen et al., 1989) because it allows the criteria values of the alternatives to be represented by real intervals rather than crisp real values between zero and one.
THE HYSTERESIS OF MAGNETIZATION IN THE GENERALIZED CRITICAL-STATE MODEL - LOW-FIELD APPROXIMATION
(1994-05-01)
CHEN, JL
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YANG, TJ
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電子物理學系
;
光電工程學系
;
Department of Electrophysics
The generalized critical-state model is extended to the low-field case by a new low-field approximation. We calculate the hysteresis loops of magnetization for H(max) < H* and H(max) > H*. We obtain new behaviors of M(H) which are different from the results derived from the Bean and Kim models. Our theory qualitatively agrees with the experimental results for high-T(c) superconductors. Some important macroscopic parameters may be obtained by fitting our theory with the experimental data.
ANALYTICAL DESIGN OF SYMMETRICAL KERR-LENS MODE-LOCKING LASER CAVITIES
(1994-05-01)
LIN, KH
;
HSIEH, WF
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
Analytical expressions for the spot size and the Kerr-lens mode-locking (KLM) strength can be represented as explicit functions of the Position in the cavity, the laser power, and the stability parameter for a four-mirror figure-Z laser resonator. The results indicate that the KLM strength achieves its maximum value at the edge of the stability range. Self-amplitude modulation and group-velocity dispersion compensation can be established by a prism pair. Simultaneously obtaining a large pumping efficiency and KLM is possible for this cavity.
IMPROVEMENT OF POLYSILICON OXIDE CHARACTERISTICS BY FLUORINE INCORPORATION
(1994-05-01)
CHERN, HN
;
LEE, CL
;
LEI, TF
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The effect of fluorine on the polysilicon oxide (polyoxide) characteristics is investigated. It is found that the polyoxide leakage current and breakdown strength are improved as fluorine is incorporated into the oxide film. Experimental results show that the improvement is believed to be due to the oxide stress relaxation rather than the change of the polyoxide/polysilicon interface texture.
TRANSFER-FUNCTION BETWEEN WAVE HEIGHT AND WAVE PRESSURE FOR PROGRESSIVE WAVES
(1994-05-01)
KUO, YY
;
CHIU, YF
;
交大名義發表
;
土木工程學系
;
National Chiao Tung University
Predicting the wave height from the subsurface wave pressure based on the pressure response factor and the correction factor has fundamental difficulties. The relationship between the measured wave height and the subsurface wave pressure was directly assessed in this study without resorting to the two parameters. Laboratory experiments were performed under various wave conditions. An empirical expression of the transfer function between wave height and wave pressure was obtained from these test data by dimensional analysis and regression analysis. In intermediate and deep water depth conditions, the transfer function was only a function of a nondimensional parameter which is composed of the angular frequency, the depth of the pressure sensor under the still water level and the acceleration of gravity. Finally, the empirical expression was compared with the experimental data and observational data from Hom-ma et al. (1966), Cavaleri (1978), Lee and Wang (1984), and Bishop and Donelan (1987). The empirical formula was found to be in sufficient correlation with these data.
THEORY OF DOUBLY RESONANT INFRARED-VISIBLE SUM-FREQUENCY AND DIFFERENCE-FREQUENCY-GENERATION FROM ADSORBED MOLECULES
(1994-05-01)
HUANG, JY
;
SHEN, YR
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光電工程研究所
;
Institute of EO Enginerring
We theoretically analyze doubly resonant infrared-visible sum-frequency (DR IVSFG) and difference-frequency generation (DR IVDFG) from a monolayer of adsorbates at an interface. our calculated results with a model molecule indicate that the resonant amplitude of nonlinear optical susceptibility of DR IVDFG and DR IVSFG processes conveys information about the electron-vibration coupling in adsorbates. Moreover, owing to a dephasing-rephasing procedure involved, DR IVDFG can also be developed into a sensitive probe for investigating the coherent phase relaxation process in adsorbed molecules without the complication of inhomogeneous broadening.