Browsing by Issue Date, starting with "1995-12-07"

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BEHAVIOR OF STEREOISOMERIC O-METHYLTYROSYL-P-NITROPHENYLALANINES WITHIN THE BETA-CYCLODEXTRIN CAVITY
(1995-12-07)
HO, TL
;
LIAO, PY
;
WANG, KT
;
應用化學系
;
Department of Applied Chemistry
Cyclisation of the L,D- and L,L-O-methyltyrosyl-p-nitrophenylalanine methyl esters is studied; in the presence of beta-cyclodextrin, reaction took place only with the L,L-isomer.
THE (N,K)-STAR GRAPH - A GENERALIZED STAR GRAPH
(1995-12-08)
CHIANG, WK
;
CHEN, RJ
;
資訊工程學系
;
Department of Computer Science
WEIGHTED INDEPENDENT PERFECT DOMINATION ON COCOMPARABILITY GRAPHS
(1995-12-08)
CHANG, GJ
;
RANGAN, CP
;
COORG, SR
;
應用數學系
;
Department of Applied Mathematics
Suppose G = (V, E) is a graph in which every vertex v is an element of V is associated with a cost c(v). This paper studies the weighted independent perfect domination problem on G, i.e., the problem of finding a subset D of V such that every vertex in V is equal or adjacent to exactly one vertex in D and Sigma{c(v): v is an element of D} is minimum. We give an O(VE) algorithm for the problem on cocomparability graphs. The algorithm can be implemented to run in O(V(2.37)) time. With some modifications, the algorithm yields an O(V + E) algorithm on interval graphs, which are special cocomparability graphs.
SPONTANEOUSLY FORMED LONG-RANGE AL-RICH AND GA-RICH ALXGA1-XAS/ALYGA1-YAS SUPERLATTICE AND OPTICAL-PROPERTIES ENHANCEMENT IN (111)A ALGAAS
(1995-12-11)
CHIN, A
;
LIN, BC
;
GU, GL
;
HSIEH, KY
;
電子工程學系及電子研究所
Spontaneously formed long-range Al-rich and Ga-rich AlxGa1-xAs/AlyGa1-yAs superlattice in(111)A was demonstrated. This was observed by cross-sectional transmission electron microscopy (TEM) in 0.75 mu m Al0.30Ga0.70As grown on (111)A GaAs substrates at 640 degrees C. In contrast, none of the above superstructure was observed by TEM on a side-by-side grown (100) oriented substrate. 15 K photoluminescence (PL) showed a 31 meV redshift and six times peak intensity enhancement in layers grown on (111)A substrates to that on (100). A reduced long-range compositional modulation can be achieved by growth at higher temperatures and is shown in the finer and moderately modulating (111)A Al0.40Ga0.60As grown at 700 degrees C. A 15 K PL linewidth of 17 meV was achieved in 700 degrees C grown (111)A A(0.40)Ga(0.60)As that is the narrowest reported linewidth for (111)A AlGaAs. (C) 1995 American Institute of Physics.
STUDIES ON CO[POLY(ETHYLENE TEREPHTHALATE-P-OXYBENZOATE)] THERMOTROPIC COPOLYESTER - THERMOMECHANICAL AND THERMODYNAMIC PROPERTIES
(1995-12-12)
SHINN, TH
;
LIN, CC
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A series of co[poly(ethylene terephthalate-p-oxybenzoate)] thermotropic copolyesters were prepared by the copolymerization of poly(ethylene terephthalate) (PET) as moiety (II) and p-acetoxybenzoic acid (POB) as moiety (I). The polymeric products obtained were subjected to solid-state polymerization. Characterization of the copolyesters by thermomechanical analysis shows that properties such as the coefficient of thermal expansion, transition temperature, and maximum softening rate temperature varied directly as a function of composition as well as did solid-state polymerization time. All thermomechanical data were found to increase with the solid-state polymerization time due to the increase in the degree of polymerization and the effect of annealing. The coefficient of thermal expansion behaves in a manner that is interpretable by the crystalline state of the copolyester. The relationship between the free-volume fraction and thermodynamic properties is further correlated for a more comprehensive discussion on its molecular arrangements. (C) 1995 John Wiley & Sons. Inc.
管管作品三首
(1995-12-15)
管管
Modification on the surface of superconducting YBa2Cu3O7-x films by microwave plasma-enhanced pulsed laser deposition
(1995-12-15)
Huang, CS
;
Tseng, TY
;
Chung, BC
;
Tsai, CH
;
Hsu, SS
Superconducting YBa2Cu3O7-x films having smooth surfaces were successfully synthesized by a microwave plasma-enhanced pulsed laser deposition (PEPLD) process. Particulates that frequently occurred in films grown by the conventional PLD process were effectively eliminated. The films were epitaxial-like. The c-axis was perpendicular to the films' surface, the a and b axes were aligned in the films' plane, and the onset and zero of the transition temperature were at T-c=90 K and T-c0=86 K, respectively. Optical emission spectroscopy indicated that the presence of oxygen plasma not only reexcited the laser-induced species via the collision process, but also produced abundant atomic oxygen in PEPLD process. The surface reaction kinetics for the formation of the thin-film process was thus greatly enhanced, which substantially improved the thin-film quality. (C) 1995 American Institute of Physics.
THE EFFECT OF NB-ADDITION ON THE LL(2) PRECIPITATES OF RAPIDLY-SOLIDIFIED AL-CR-ZR ALLOY
(1995-12-15)
CHUANG, MS
;
TU, GC
;
交大名義發表
;
材料科學與工程學系
;
National Chiao Tung University
管管作品三首
(1995-12-15)
管管
管管作品三首
(1995-12-15)
管管
管管作品三首
(1995-12-15)
管管
Effects of oxygen-argon mixing on the electrical and physical properties of ZrTiO4 films sputtered on silicon at low temperature
(1995-12-15)
Chang, DA
;
Lin, P
;
Tseng, TY
;
材料科學與工程學系
;
電子工程學系及電子研究所
Zirconium titanate (ZrTiO4) thin films (200-260 nm) on p-type (100) Si substrates were prepared using radio-frequency sputter deposition at room temperature in atmosphere of various O-2/Ar mixing ratio (from 0/100 to 20/80). All films exhibited a (020) preferred orientation and small grain size with increasing O-2/Ar ratio, as shown by x-ray diffraction. The variations of dielectric constant, fixed oxide charge, and interface trapped charge with O-2/Ar ratio are studied with an Al/ZrTiO4/Si structure. The refractive index and dielectric constant varied in ranges 2.34-2.26 and 20-16 for the as-deposited films. Within the range investigated, crystallinity appears to have a stronger influence on the densities of charge-trapping centers in the films than oxygen stoichiometry, and the latter may determine the leakage current density. A remarkable two orders of magnitude decrease in leakage current to 5.6X10(-9) A/cm(2) at 0.1 MV/cm and an increase in breakdown field beyond 1.2 MV/cm are observed in the film deposited without oxygen after a 400 degrees C annealing in air for 1 h. The current transport in ZrTiO4 film is dominated by the Poole-Frenkel mechanism. (C) 1995 American Institute of Physics.
管管作品三首
(1995-12-15)
管管
Wide bandwidth AlAs/AlGaAs tandem Bragg reflectors grown by organometallic vapor phase epitaxy
(1995-12-18)
Lee, WI
;
交大名義發表
;
電子物理學系
;
National Chiao Tung University
;
Department of Electrophysics
Wide bandwidth AlAs/Al0.6Ga0.4As tandem Bragg reflectors were grown by organometallic vapor phase epitaxy. Quarter-wave reflector stacks designed for different wavelengths were placed in cascade in epitaxially grown structures to expand the high reflectance bands. Intermediate low-index layers were put in between every two stacks to suppress the transmission peaks in the centers of the combined high reflectance bands. While a single-stack structure showed a full width half-maximum bandwidth of 500 Angstrom, the two-stack and the three-stack structures effectively doubled and tripled this bandwidth to approximately 1000 and 1500 Angstrom, respectively. (C) 1995 American Institute of Physics.
The first exclusive regioselective fragmentation of primary ozonides controlled by remote carbonyl groups
(1995-12-18)
Lin, CC
;
Wu, HJ
;
應用化學系
;
Department of Applied Chemistry
Ozonolysis of compounds 1a-1d in CDCl3 at -78 degrees C regioselectively and stereoselectively gave the corresponding final ozonides 2a-2d as the sole product, which, after treatment with triethylamine, gave the novel convex tetraquinane era-cages 9a-9d in high yields respectively.
Synthesis of furan-, thiophene- and pyrrole-fused sultines and their application in Diels-Alder reactions
(1995-12-21)
Chung, WS
;
Lin, WJ
;
Liu, WD
;
Chen, LG
;
交大名義發表
The synthesis of 1,4-dihydrofurano[3,4-d]-3,2-oxathiine 2-oxide 8, 5,7-dimethyl-1,4-dihydrothieno[3,4-D]-3,2-oxathiine 2-oxide 9 and 1,4-dihydro-6-tosylpyrrolo[3,4-D]-3,2-oxathiine 2-oxide 10, precursors for nonclassical heteroaromatic o-quinodimethanes, and their application in the Diels-Alder reactions are reported.
Recognition of handwritten similar Chinese characters by neural networks
(1996)
Fu, HC
;
Chen, JM
;
資訊工程學系
;
Department of Computer Science
清大有種會啄人的鳥
(文史哲, 1996)
沈定濤
Effects of oxygen content on the penetration depth in YBCO thin films
(1996)
Hsieh, MC
;
Tseng, TY
;
Fu, CM
;
Wu, KH
;
Juang, JY
By varying oxygen content of the microstrip line resonator of YBa2Cu3O7-x, the effective penetration depth was studied. Based on the two-fluid model, we fit the data of the resonant frequency by means of the inductance formula. It allows us to determine the zero-temperature penetration depth of the fully oxygenated,(O approximate to 7) and oxygen deficient (O = 6.8) states in the same strip to be 483.2 nm and 789.8 nm, respectively. The ratio of the superconducting carrier densities with different oxygen contents is then derived and found to be consistent with the result of Hall measurement. A correlation between oxygen contents and charge carriers of the samples will be obtained in our work as accurately as possible.
II-VI半導體量子點和微腔液滴之超快同調光譜研究
(1996)
謝文峰
;
HSIEH WEN-FENG
;
國立交通大學光電工程研究所