Showing papers by "Kyungpook National University published in 1989"
TL;DR: In this paper, a series of ZrO2 catalysts modified with sulfur compounds were prepared by treating Zr(OH)4 with sulfate ion and by treating H2S, CS2, and SO2 followed by oxidation.
105 citations
TL;DR: An algorithm for computing such interpolating units is presented which requires a lower degree unit than other available algorithms.
73 citations
TL;DR: In this paper, the linear driving force (LDF) approximation has been used in the analysis of chromatography and packed bed adsorbers, and the main advantage of the approximation is in its greatly simplified formulas for unsteady-state diffusion in porous particles.
Abstract: The linear driving force (LDF) approximation has been used in the analysis of chromatography and packed bed adsorbers. The main advantage of the approximation is in its greatly simplified formulas for unsteady-state diffusion in porous particles. Instead of the partial differential equation, the LDF approximation gives ordinary differential equations. The LDF expressions either do not distinguish between the adsorbed phase and the diffusing phase in the particles or consider the diffusing phase only. Adsorption is one of the primary phenomena in most processes involving porous particles, and except in very fine pore structures such as in zeolite crystals, the two phases are distinguishable. In this paper, LDF approximations which take into account reaction, adsorption, as well as unsteady-state diffusion, are developed.
61 citations
TL;DR: In this paper, the surface structure and composition of the prepared thin films are investigated by electron spectroscopy for chemical analysis and X-ray diffractometry, and the electrical properties of the thin films and the effect of Pt addition on the gas sensing characteristics have also been investigated.
61 citations
TL;DR: In this paper, it was shown that resistance of monomer diffusion through the polymer film should be one of the significant parameters for the apparent polymerization rate when very high crystalline polymers, like high density polyethylene, isotactic polypropylene etc., are produced.
Abstract: By using an extremely high stereospecific catalyst, three kinds of copolymerizations were carried out with combinations of monomers which differ in the crystallinity of the homopolymers. Addition of a small quantity of comonomer to the homopolymerization systems producing very high crystalline polymers was found to cause a remarkable increase in the apparent polymerization rate as well as a marked decrease in the polymer crystallinity. Such an irregular increase in the polymerization activity was, however, not observed when a small amount of comonomer was added to the homopolymerization systems producing low-crystalline or amorphous polymers. These observations have led to the conclusion that resistance of monomer diffusion through the polymer film should be one of the significant parameters for the apparent polymerization rate when very high crystalline polymers, like high density polyethylene, isotactic polypropylene etc., are produced.
54 citations
TL;DR: In this paper, the authors calculate modifie des parametres d'un procede modele a grand temps retard afin d'ameliorer les performances du regulateur.
Abstract: Calcul modifie des parametres d'un procede modele a grand temps retard afin d'ameliorer les performances du regulateur
51 citations
TL;DR: A new window, w(t)=0.62-0.48 mod t mod +0.38 cos 2 pi t, mod tmod
Abstract: A new window, w(t)=0.62-0.48 mod t mod +0.38 cos 2 pi t, mod t mod
48 citations
TL;DR: In this paper, the two-point cluster function C2(r1,r2) was determined for a D-dimensional interpenetrable-sphere continuum model from Monte Carlo simulations.
Abstract: The two‐point cluster function C2(r1,r2) is determined for a D‐dimensional interpenetrable‐sphere continuum model from Monte Carlo simulations. C2(r1,r2) gives the probability of finding two points, at positions r1 and r2, in the same cluster of particles, and thus provides a measure of clustering in continuum‐percolation systems. A pair of particles are said to be ‘‘connected’’ when they overlap. Results are reported for D=1,2, and 3 at selected values of the sphere number density ρ and of the impenetrability index λ, 0≤λ≤1. The extreme limits λ=0 and 1 correspond, respectively, to the cases of fully penetrable spheres (‘‘Swiss‐cheese’’ model) and totally impenetrable spheres.
30 citations
TL;DR: In this article, an investigation of the equivalent pi circuit representation for the transverse slit in the wall of a transverse electromagnetic (TEM) parallel-plate waveguide is presented.
Abstract: An investigation of the equivalent pi circuit representation for the transverse slit in the wall of a transverse electromagnetic (TEM) parallel-plate waveguide is presented. For the narrow slit, approximate analytic expressions for the equivalent circuit parameters are given in terms of the centerline representation and, for the arbitrarily width slit, the equivalent circuit parameters are considered by the method of moments in terms of both the centerline representation and edge representation, and various characteristics of the equivalent pi admittance circuit representation are discussed. A critical look is taken at the validity of the previous model of th E-plane gap coupling between two rectangular microstrip patch antennas, and the improved model is considered for the narrow slit (gap) width case. >
25 citations
University of South Carolina1, Ohio State University2, University of California, Davis3, KEK4, Konan University5, University of Minnesota6, Rutgers University7, Korea University8, Niigata University9, University of Rochester10, University of Tsukuba11, Saga University12, Kyungpook National University13, Chuo University14, Tokyo Institute of Technology15, Saitama University16
TL;DR: In this paper, a possible substructure of the electron and muon is investigated in terms of chiral invariant contact interactions and also in the absence of excited lepton production.
22 citations
TL;DR: In this paper, the shape of ZnO grains in Bi 2 O 3 liquid solution is investigated as a function of temperature, and the grain shape dispersed in liquid is discussed in terms of interfacial energy minimization and growth rate during Ostwald ripening.
University of Rochester1, University of Tsukuba2, Louisiana State University3, Virginia Tech4, University of South Carolina5, Ohio State University6, University of California, Davis7, Konan University8, University of Minnesota9, Rutgers University10, Niigata University11, Saga University12, Korea University13, Kyungpook National University14, Chuo University15, Tokyo Institute of Technology16, Saitama University17
TL;DR: In this paper, the mass of the Z 0 boson, M Z, and the QCD scale parameter, Λ MS, were derived from the fit of the standard model to these measurements and those at lower energies.
01 Dec 1989
TL;DR: The adaptive image segmentation system is presented, which incorporates a genetic algorithm to adapt the segmentation process to changes in image characteristics caused by variable environmental conditions such as time of day, time of year, clouds, etc.
Abstract: We present the first closed loop image segmentation system which incorporates a genetic algorithm to adapt the segmentation process to changes in image characteristics caused by variable environmental conditions such as time of day, time of year, clouds, etc. The segmentation problem is formulated as an optimization problem and the genetic algorithm efficiently searches the hyperspace of segmentation parameter combinations to determine the parameter set which maximizes the segmentation quality criteria. The goals of our adaptive image segmentation system are to provide continuous adaptation to normal environmental variations, to exhibit learning capabilities, and to provide robust performance when interacting with a dynamic environment. We present experimental results which demonstrate learning and the ability to adapt the segmentation performance in outdoor color imagery.
TL;DR: In this paper, the authors used the Fineman-Ross and Kelen-Tudős method to calculate the monomer reactivity ratios for copolymerizations of ethylene with various α-olefins (propene, 1-butene,1-hexene and 4-methyl-1-pentene).
Abstract: The recently found catalyst system, composed of Solvay-type TiCl3 and (RCp)2TiMe2, producing extremely high isospecific polyolefins, was used for copolymerizations of ethylene with various α-olefins (propene, 1-butene,1-hexene and 4-methyl-1-pentene) to obtain monomer reactivity ratios for isospecific centers. It was found that no homopolymer was formed actually. Using the copolymer composition obtained by 13C NMR, the monomer reactivity ratios were calculated according to the Fineman-Ross and Kelen-Tudős method. For the ethylene/propene pair the same values of reactivity ratio were also obtained from the diad distribution of comonomers. The relative reactivity of these olefins was found to decrease in the following order; ethylene > propene > 1-butene > 1-hexene > 4-methyl-1-pentene.
TL;DR: In this article, a copolymerization of 8-quinolinyl acrylate (QA) with acrylamide (AM) was carried out in dimethyl sulfoxide at 70°C in order to synthesize hydrophilic polymers which are able to release 8-hydroxyquinoline (HQ).
TL;DR: In this paper, the effect of cation on the dealumination process was found to be related to the pH of the solution, and the acid attack reaction was initiated by an acid attack.
Louisiana State University1, University of California, Davis2, Virginia Tech3, University of South Carolina4, Ohio State University5, University of Minnesota6, Rutgers University7, Niigata University8, University of Rochester9, University of Tsukuba10, Saga University11, Korea University12, Kyungpook National University13, Chuo University14, Tokyo Institute of Technology15, Saitama University16
TL;DR: In this paper, the forward-backward asymmetries and total cross sections for these reactions are found to be in agreement with predictions of the standard model of the electro-weak interactions.
TL;DR: In this paper, an analysis of the structure de bande dans le domaine de temperature de l'effet de memoire reversible is presented. But this analysis is limited to phase α.
01 Jan 1989-International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry
TL;DR: In this paper, the effect of γ-irradiation at 0.1 kGy on the quality of garlic bulbs (Allium sativum L.) during storage at 3±1°C and 80±5% RH for 10 months was investigated.
TL;DR: In this paper, the reduction of Ti(III) to Ti(II) by aluminum alkyls was considered as a main reason for the catalytic activity decay in propylene polymerization.
Abstract: Ethylene-propylene copolymerizations were carried out using conventional and high activity supported Ziegler-Natta catalysts to examine the reduction of Ti(III) to Ti(II) by aluminum alkyls, which has been considered as a main reason for the catalytic activity decay in propylene polymerization. For the catalyst system cocatalyzed with DEAC, the reduction was negligible regardless of the catalyst types, while an irreversible catalyst modification such as the reduction reaction occurred significantly for the catalyst with TEA.
TL;DR: In this paper, Dodziuk and Singer conjectured that H 2 p(M) = 0 if p ≠ m/2 and dim H 2 m/(2) = ∞, where H 2 is the space of L 2-harmonic forms on M.
Abstract: Let M be a complete simply-connected riemannian manifold of even dimension m. J. Dodziuk and I.M. Singer ([D1]) have conjectured that H2 p(M) = 0 if p ≠ m/2 and dim H2 m/2(M) = ∞, where H2 *(M) is the space of L2-harmonic forms on M.
21 Jun 1989
TL;DR: In this paper, the problem of finding a compensator for a feedback system which minimizes an H2-norm of a weighted sensitivity function for a nominal stable plant while preserving the stability of the feedback system when the nominal plant is perturbed to another, possibly unstable plant is considered.
Abstract: The problem considered is that of finding a compensator for a feedback system which minimizes an H2-norm of a weighted sensitivity function for a nominal stable plant while preserving the stability of the feedback system when the nominal plant is perturbed to another, possibly unstable plant. It is known that the problem of simultaneous stabilization of two plants can be reduced to an interpolation problem with units in H?. The interpolating unit may be parameterized in terms of an arbitrary strongly bounded real function U(s). This parameterization of robustly stable compensators in terms of bounded real functions is referred to as U-parameterization, and represents a direct extension of the Q-parameter theory used for the design of nominally stable feedback systems. We propose here the use of this free parameter to minimize H2-norm for a nominal plant.
TL;DR: Infusate with hemocoagulase (1 NIH thrombin unit/100 ml of BSS plus) is not toxic to retinal tissue and appeared to be a useful agent for the control of intraocular bleeding during vitreous surgery.
Abstract: The effects of hemocoagulase in injectable form (hemocoagulating enzymatic fraction of South American snake Bothrops jararaca venom provided by Ravizza) on the control of intraocular bleeding during vitreous surgery were evaluated in rabbit eyes. Intraocular infusion solution with hemocoagulase (1 NIH thrombin unit/100 ml of BSS plus) significantly reduced the bleeding time. Electroretinogram b-wave and electroretinogram c-wave showed no abnormality. Infusate with hemocoagulase (1 NIH thrombin unit/100 ml of BSS plus) is not toxic to retinal tissue and appeared to be a useful agent for the control of intraocular bleeding during vitreous surgery.
TL;DR: In this article, two cobalt layer silicates were synthesized by hydrothermal treatment at 275 c and 54 atm from corresponding stoichiometric coprecipitate of cobalt hydroxide and silica.
Abstract: Two cobalt layer silicates were synthesized by hydrothermal treatment at 275‡C and 54 atm from corresponding stoichiometric coprecipitate of cobalt hydroxide and silica. From IR absorption spectra and X-ray diffraction patterns, one sample was proved to be cobalt montmorillonite [Co[3Si[2O[5
2(OH)2, while the structure of the other was cobalt antigorite [Co3Si2O5(OH)4] of one silica layer combined with an octahedral layer of the type Co3
2+ (OH)6.
TL;DR: In this article, a scale and rotation invariant polar-logarithmic coordinate transformation is used to achieve deformation invariant pattern recognition using a computer generated hologram (CGH).
Abstract: Scale and rotation invariant polar-logarithmic coordinate transformation is used to achieve deformation invariant pattern recognition. The coordinate transformation is produced by a computer generated hologram (CGH). The mask fabricated by a photo (ultra-violet light) pattern generator for the In( r )-θ coordinate transformation is made of the CGH whose transmission function is derived by the use of the stationary phase method. The optically produced coordinate transformed input pattern is interfaced to an optical correlator. A BaTiO 3 single crystal is used as a real-time matched filter based on real-time holography.
TL;DR: The hybridizing kinetics of hydrogen adsorption on a surface was studied as a function of temperature and time and the stickingcoefficient of the two-surface state in terms of the bulk fraction /ital x/ was obtained byuse of the method of Pick and Greene.
Abstract: On the basis of the two-state model, the kinetics of hydrogen adsorption ona surface was studied as a function of temperature and time. Following thismodel, we formulated the hybridizing kinetics and obtained the stickingcoefficient of the two-surface state in terms of the bulk fraction /ital x/ byuse of the method of Pick and Greene. We calculated the chemisorption energyand the activation energy for chemisorption by use of the theoreticalcalculation condition of Davenport, Pick and Greene, and Pick. The estimatedchemisorption energy is 13.5--14.3 kcal/mol H and the activation energyfor chemisorption is 0.8--1.6 kcal/mol H. The relation between bulkfraction and heating rate was also obtained by application of theflash-desorption theory to this model.
TL;DR: In this article, the reaction of phenacyl p-bromobenzenesulfonate (brosylate) with substituted pyridines at 1-1500 atm and 35, 45, and 55°C in acetonitrile were carried out by electric conductivity method.