Showing papers by "National Tsing Hua University published in 1985"
135 citations
TL;DR: Palladium catalysts on various supports were prepared for strong metal-support interaction (SMSI) studies as discussed by the authors, and the reduction and hydrogen sorption for these catalysts were investigated by a combination of temperature-programmed reduction and temperature-resolved sorption techniques.
98 citations
TL;DR: Etude du bruit en 1/f pres du seuil de percolation X c de melanges carbone-cire diverge avec une variation en loi de puissance en X-X c.
Abstract: $\frac{1}{f}$ noise near the percolation threshold ${X}_{c}$ of carbon-wax mixtures was carefully studied. The noise spectral density was found to diverge with a power-law dependence on $X\ensuremath{-}{X}_{c}$. Our results might be qualitatively explained by carrier-number fluctuations, produced by tunneling conduction, in infinite clusters.
70 citations
TL;DR: In this article, it was shown that the number of polymer particles and the rate of polymerization at steady state is dependent on 1-power of the comonomer concentration and 1/2 power of the initiator concentration.
Abstract: The emulsifier-free emulsion polymerizations of styrene in the presence of the surface active comonomer, undecylenic isethionate sodium salt (at concentration below its critical micelle concentration), and of the initiator, potassium persulfate, indicate that the number of polymer particles and the rate of polymerization at steady state is dependent on 1-power of the comonomer concentration and 1/2-power of the initiator concentration. This result suggests a homogeneous nucleation mechanism by which particles are formed from coiled-up oligomeric radical chains originally dissolved in the aqueous phase. Size distribution of the particles is rather narrow and has a uniformity very close to one (ca. 1.02) after 30% conversion. Addition of salt such as sodium sulfate to increase the ionic strength in the aqueous phase results in a formation of micelles (which can grow to become polymer particles) in addition to the formation of polymer particles through the homogeneous nucleation mechanism. Variation of the ionic strength leads to a variation in the number of polymer particles due to a competition between these two nucleation mechanisms and gives a minimum of the number of polymer particles and a maximum of the average particle diameter.
51 citations
TL;DR: A method of on‐line optimal control for fed‐batch culture of bakers yeast production by using the data from the feed rate and the specific growth rate to achieve an optimal feed rate.
Abstract: A method of on-line optimal control for fed-batch culture of bakers yeast production is proposed. The feed rate is taken as the control variable. The specific growth rate of the yeast is the output variable and is determined from the balance equation of oxygen. A moving model is obtained by using the data from the feed rate and the specific growth rate. Based on the moving model, an optimal feed rate for fed-batch culture is then achieved. 11 references.
47 citations
TL;DR: In this article, the effects of fluid properties, pool subcooling, crevice length, and gap size on the boiling behavior and critical heat flux (CHF) were studied.
Abstract: Experimental results of the pool boiling in horizontal narrow annuli are reported. The effects of fluid properties, pool subcooling, crevice length, and gap size on the boiling behavior and the critical heat flux (CHF) are also studied. The CHF decreases with decreasing gap size or increasing length of the annuli. The lower CHF of narrow crevices may be explained by the thin film evaporation. A semi-empirical correlation is established for the CHF of pool boiling in horizontal confined spaces. This correlation is compared with the CHF data of the present experiment. Satisfactory agreement is obtained.
41 citations
TL;DR: In this article, the formation and structures of epitaxial suicides are described, and lattice match criteria for the growth of suicide epitaxy are assessed, and the effects of anharmonicity in the interatomic force of overlayer on the heteroepitaxial growth and pseudomorphism are discussed.
Abstract: Recent progresses in the epitaxial growth of refractory metal suicides, FeSi2 and manganese suicides on silicon are reviewed. The formation and structures of epitaxial suicides are described. Factors affecting the suicide epitaxy are examined. The lattice match criteria for the growth of epitaxial suicides are assessed. The effects of anharmonicity in the interatomic force of overlayer on the heteroepitaxial growth and pseudomorphism are discussed. The properties and possible applications of epitaxial suicides are summarized. Prospects for the study of epitaxial suicides are addressed.
39 citations
TL;DR: By using a thermodynamic approach, the image force of the dislocation due to the semi-infinite crack in an infinite medium has been completed in this paper, which can be applied to the phase transformation toughening in zirconia.
36 citations
TL;DR: In this article, a rigorous hybrid finite element procedure for the analysis of the thermoelastic problems with mixed-mode cracks is presented, in which hybrid singular elements are used around the crack-tip and high-order isoparametric regular elements are taken elsewhere.
36 citations
TL;DR: In this paper, a preirradiation grafting of acrylic acid and methacrylic acid onto polyethylene (LDPE) films was studied, and the influences of crystallinity, dosage, and storage period on the grafting behavior were investigated from the viewpoint of practical application.
Abstract: The method of preirradiation grafting of acrylic acid and methacrylic acid onto polyethylene films was studied. The trapped radicals and hydroperoxides or diperoxides appeared to be able to induce graft polymerization. Mohr's salt was added to depress homopolymerization. The influences of crystallinity, dosage, and storage period on the grafting behavior were investigated from the viewpoint of practical application. At elevated temperature, the degree of grafting increased rapidly with reaction time initially, and then leveled off to the value of final percent grafting. Dosage and storage periods had greater extent of influence on the final percent grafting of LDPE than on that of HDPE. Electrical properties, transport properties, and mechanical properties were measured to compare the differences between acrylic-acid-and methacrylic-acid-grafted copolymer films. It was found that the properties of methacrylic-acid-grafted copolymer film was superior to those of acrylic-acid-grafted copolymer film, especially in electrical conductivity. The KOH diffusion test confirmed that grafting occurred not only on the surface but also in the interior of the polymer matrix, and the grafting is believed to proceed from the surface to the interior of the matrix.
35 citations
TL;DR: In this paper, the negative-parity states of N =88 isotones are studied systematically in terms of the interacting boson approximation, and the effect of p bosons on the energy spectra and electromagnetic transitions is discussed.
TL;DR: In this paper, the degradation of AISI 1090 steel was mechanically tested after precharging or dynamically charging with hydrogen at high fugacity, and the degradation was manifested as an early onset of plastic instability in the form of shear bands leading to premature fracture.
Abstract: Spheroidized AISI 1090 steel was mechanically tested after precharging or dynamically charging with hydrogen at high fugacity. The degradation of properties was greater for plane-strain tensile tests or notched bend tests than for tensile tests of round bars. In precharged specimens the degradation was manifested as an early onset of plastic instability in the form of shear bands leading to premature fracture. In dynamically charged specimens, hydrogen caused brittle fracture in a mode I manner. The results are compared with those in other hydrogen embrittlement studies and discussed in relation to theories for the onset of plastic instability.
TL;DR: In this paper, the rate constants of the reaction between OH and H2S in He, N2, and O2 over the temperature range 245-450 K have been determined using the discharge flow-resonance fluorescence technique.
Abstract: The rate constants of the reaction between OH and H2S in He, N2, and O2 over the temperature range 245–450 K have been determined using the discharge flow-resonance fluorescence technique. At 299 K, k1 = (4.4 ± 0.7) × 10−12 cm3 molecule−1 s−1. The temperature dependence of the rate constant can be fitted either by k1 = 5.6 × 10−12 exp(−57/T) or by k1 = (3.8 × 10−19)T2.43 exp(732/T) to within 8 and 9%, respectively. However, the non-Arrhenius behavior can be confidently confirmed. The absence of the pressure dependence and the third-body effect at low temperature suggest that the complex formation mechanism is not important over the temperature range of our study.
TL;DR: In this article, an assumed hybrid-displacement finite element model is presented to deal with the flutter problems of thin cracked panels, and the aerodynamic properties of rectangular-shaped hybrid crack elements around the crack tip embedded with proper stress singularities are derived.
Abstract: An assumed hybrid-displacement finite element model is presented to deal with the flutter problems of thin cracked panels. Based on a modified Hamilton's principle for nonconservative systems with relaxed continuity requirements for deflections and normal slopes at the interelement boundary, the aerodynamic properties of rectangular-shaped hybrid crack elements around the crack tip embedded with proper stress singularities are derived. Interelement compatibility conditions are satisfied through the use of a Lagrangian multiplier technique and the assumption of interelement boundary deflections. First, for verification purposes, the flutter analyses of noncracked panels are illustrated. Excellent agreement between the computed results and referenced solutions is observed. To investigate the nature of the fluttering instability, both the divergent- and oscillatory-type fluttering instabilities are discussed in detail. Several typical types of cracked panels found in aeronautical structures in arbitrarily directed supersonic flows are then studied. The influences of crack lengths and flow directions on the evaluation of the critical speed and type of instability are also drawn. Finally, the important role of the hybrid crack element in dealing with flutter problems of thin cracked panels is demonstrated.
TL;DR: On essaie d'identifier une nouvelle phase ordonnee de surstructure dans l'alliage Fe-0, 1% Al-29, 9% Mn-2,9% Cr en poids as mentioned in this paper.
TL;DR: The design algorithm of a differential group programmable logic array (DGPLA) to generate the precise binary logarithm function is suggested and can reach an optimal condition such that the number of bits in a PLA is minimized, while the error is still kept as small as possible.
Abstract: The design algorithm of a differential group programmable logic array (DGPLA) to generate the precise binary logarithm function is suggested. It can reach an optimal condition such that the number of bits in a PLA is minimized, while the error is still kept as small as possible. Thus, the space in the PLA is saved, estimated at only 15.94 percent of the space for a readonly memory (ROM) counterpart.
TL;DR: Based on the hydrogenic effective mass approximation, an image-potential method for the treatment of impurities in semiconductors with a boundary surface is developed in this paper, where the Schr\"odinger equation is separable in prolate spheroidal coordinates.
Abstract: Based on the hydrogenic effective-mass approximation, an image-potential method is developed for the treatment of impurities in semiconductors with a boundary surface. The Schr\"odinger equation is separable in prolate spheroidal coordinates ($\ensuremath{\xi}, \ensuremath{\eta}, \ensuremath{\varphi}$). Generalized spheroidal wave equations of $\ensuremath{\xi}$ and $\ensuremath{\eta}$ resulting from the separation constitute the basic equations for the study of surface effects on impurity states.
TL;DR: In this article, the authors used the unique property of the convolution integral of the shifted Legendre polynomials (SLP) to solve convolutional integral equations.
Abstract: The unique property of the convolution integral of the shifted Legendre polynomials is used to solve convolution integral equations. Three important types of integral equations: (i) first-order of the first kind, (ii) second-order of the first kind, and (iii) the integral equation of the second kind, are studied in the present paper. The basic idea in solving the integral equation is that the state variables are expressed in terms of the shifted Legendre polynomial series. Series of the algebraic equations of the expansion coefficients are obtained and are calculated recursively by the powerful proposed computational algorithm. Examples are given for illustration. Very satisfactory computational results are obtained.
TL;DR: From the fronds of Alsophila spinulosa TRYON biflavonoids Hegoflavone A (I) and B (II) were isolated and their structures were elucidated by spectroscopic analysis and chemical degradation as discussed by the authors.
Abstract: From the fronds of Alsophila spinulosa TRYON biflavonoids Hegoflavone A (I) and B (II) were isolated and their structures were elucidated by spectroscopic analysis and chemical degradation to be 2, 3-dihydro-3'''-hydroxy-6, 6'''-biapigenin (I) and 2, 3-dihydro-6, 6'''-biluteolin (II) respectively. These are the first reports of a C-6/C-6'''-linked biflavonoid in nature.
TL;DR: In this paper, the authors present new reliability optimization models which can be formulated as parametric nonlinear integer programming problems, and the solution methods are illustrated with examples and flow charts.
Abstract: In practical reliability optimization models, finding an optimal solution to the model is not the only requirement. One may also be interested in solutions that are close to optimum, or one may want to know what happens if a change is made in the model. This paper presents new reliability optimization models which can be formulated as parametric nonlinear integer programming problems. Solution methods are illustrated with examples and flow charts.
TL;DR: In this paper, the behavior of benzene hydrogenation over Ni/TiO 2 -ZrO 2 catalyst system was studied and the results showed that the activity for benzene hydroge
TL;DR: The good agreement between experiment and prediction indicated the validity of the established model and the fact that d-glucose and d-galactose are mutually exclusive for the inhibition was verified by Dixon plots.
TL;DR: This work gives explicit formulas for all components of the Riemannian connection and curvature tensor for a class of metrics which describe low-energy deformations in Kaluza-Klein theories with homogeneous fibers.
Abstract: We give explicit formulas for all components of the Riemannian connection and curvature tensor for a class of metrics which describe low-energy deformations in Kaluza-Klein theories with homogeneous fibers.
TL;DR: A facility for in vivo prompt gamma activation analysis using moderated neutron beams from a 0.1 W mobile nuclear reactor that combines the advantages of mobility with high sensitivity of detection of a toxic element under low neutron and gamma doses is described.
TL;DR: In this paper, the Shirakawa method was used to synthesize polyacetylene (PA) on a platinum surface, which has a granular morphology and high surface area (79 m2/g).
Abstract: Polyacetylene (PA) deposited on a platinum surface is synthesized by electrochemical polymerization of acetylene in a cell with platinum strip as cathode, nickel strip as anode, and nickel bromide in acetonitrile as electrolyte. The electrolytic solution is presaturated with acetylene. The PA so produced has a granular morphology and high surface area (79 m2/g), and is insoluble. Polymerization at lower temperature gives higher content in cis units. It has the same chemical structure as that produced using the Shirakawa method as examined by elemental analysis, infrared spectroscopy, x-ray diffraction, and differential scanning calorimetry.
TL;DR: It is shown that the general problem of designing a multi-attribute file system which is optimal with respect to partial match queries is an NP-hard problem and the Cartesian product file design problem is related to the Composite Number Problem.
TL;DR: In this paper, the effect of cold work and alpha annealing on the microstructure and corrosion resistance of Zircaloy-4 in 450°C steam was investigated.