Showing papers by "Pusan National University published in 1992"
TL;DR: Results of a performance comparison indicate that the proposed timestamp-based cache coherence scheme performs significantly better than previous software-assisted schemes, especially when the processors are carefully scheduled so as to maximize the reuse of cache contents.
Abstract: A timestamp-based software-assisted cache coherence scheme that does not require any global communication to enforce the coherence of multiple private caches is proposed. It is intended for shared memory multiprocessors. The scheme is based on a compile-time marking of references and a hardware-based local incoherence detection scheme. The possible incoherence of a cache entry is detected and the associated entry is implicitly invalidated by comparing a clock (related to program flow) and a timestamp (related to the time of update in the cache). Results of a performance comparison, which is based on a trace-driven simulation using actual traces. between the proposed timestamp-based scheme and other software-assisted schemes indicate that the proposed scheme performs significantly better than previous software-assisted schemes, especially when the processors are carefully scheduled so as to maximize the reuse of cache contents. This scheme requires neither a shared resource nor global communication and is, therefore, scalable up to a large number of processors. >
70 citations
TL;DR: In this article, polyurethane (PU) ionomers were prepared using various types of polyol (PTAd, PCL, PTMG, and PPG) and isocyanate (MDI, HDI, and IPDI), together with different extender (DMPA) contents, degree of neutralization, and number average molecular weight (Mn).
Abstract: Polyurethane (PU) ionomers were prepared using various types of polyol (PTAd, PCL, PTMG, and PPG) and isocyanate (MDI, HDI, and IPDI), together with different extender (DMPA) contents, degree of neutralization, and number average molecular weight (Mn) of polyol. Modulus (E′), strength (σb), and glass transition temperature (Tg) significantly increased with the increased amount of extender and extender neutralization. Among three of the iocyanate used, PU from MDI gave the highest modulus, strength, andTg. With regard to theMn of PTAd (600, 1000, 2000), PU from PTAd 600Mn gave the highest modulus, strength, andTg, due probably to the highest hard segment content and phase mixing. On the other hand, PU from PTAd 2000Mn gave significantly improved strength over PTAd 1000Mn, and the highest elongation. The results were interpreted in terms of soft-segment crystallization, and soft-hard phase separation, which was concluded from the lowered softTg.
63 citations
TL;DR: In this paper, the effect of fiber diameter and surface treatment on the interfacial shear strength between glass fiber and matrix (epoxy and high-density polyethylene) has been investigated.
Abstract: The effect of fiber diameter and the surface treatment of fiber on the interfacial shear strength between glass fiber and matrix (epoxy and high-density polyethylene) has been investigated. Pullout experiments for measuring the interfacial shear strength have been carried out through use of microbonding and the solution microbond test methods for the epoxy and HDPE composite systems, respectively. From this study, it has been found that the interfacial shear strength decreased with the increasing fiber diameter regardless of the type of fiber surface treatment for both resin systems.
39 citations
TL;DR: The reaction of α-trimethylsilylmethyl-methyl-substituted divinyl ketones with FeCl 3 gave α-methylene-cyclopentanones as mentioned in this paper.
39 citations
TL;DR: Aldehydes are efficiently oxidized to acyl azides by azidotrimethylsilane and chromic anhydride at room temperature (aromatic), or at −10°C (aliphatic) as discussed by the authors.
34 citations
TL;DR: In this article, the effects of the chemical structure of reactive urethane acrylate prepolymers and diluents (reactive monomers) and overall composition of the prepolymer/diluent on the properties of the UV-curable polyurethANE acrylates for primary optical fiber coating were studied.
Abstract: Studies have been made on the effects of the chemical structure of reactive urethane acrylate prepolymers and diluents (reactive monomers) and overall composition of the prepolymer/diluent on the properties of the UV-curable polyurethane acrylates for primary optical fiber coating. We prepared several urethane acrylate prepolymers from two different isocyanates, 4,4′-dicyclohexylmethane diisocyanate (HMDI) or isophorone diisocyanate (IPDI), and two different polyols, polybutadiene diol (PBD) or polypropylene oxide diol (PPG), and 2-hydroxyethyl acrylate (HEA) with dibutyl tin dilaurate as a photoinitiator. UV-curable coating materials were formulated from the prepolymers and 2,2-dimethyl 2-phenyl acetophenone as a photoinitiator with one of four different diluents such as 1-vinyl 2-pyrrolidone (VP), lauryl methacrylate (LMA), acrylic acid 2-ethyl hexyl ester (AEHE), and acrylic acid n-butyl ester (ABE). It was found that AEHE is the desirable diluent in the formulation of the primary fiber-coating material. The desirable composition of PBD, when mixed PBD/PPG diols are used, should be about 50 wt % for optimum formulation. Most of the urethane acrylate prepolymers prepared in this study could be applied in the formulation of primary optical fiber coating and exhibited good properties of buffer functions, including low glass transition temperature, low modulus even at low temperature, say, below −40°C, high refractive index, and low viscosity. © 1992 John Wiley & Sons, Inc.
34 citations
TL;DR: Eight cases of a seldom reported complication following fracture-separation of the distal end of the humerus in children are discussed, speculated that this complication is due to avascular necrosis of the DistalEnd of the Humerus, and that fracture- separating is more common than reported.
Abstract: Fracture-separation of the distal end of the humerus in children has been reported infrequently, and may be misdiagnosed as a fracture of the condyle or a traumatic dislocation of the elbow We discuss eight cases of a seldom reported complication following fracture-separation of the distal end of the humerus This complication consists of dissolution of the trochlea within three to six weeks postinjury and a defect of the medial or central part of the condyle that develops later The fractures were severely displaced fracture-separation of the distal end of the humerus with large medial or lateral metaphyseal fragment, but initially misdiagnosed as a fracture of the medial, lateral condyle or a traumatic dislocation of the elbow in six of eight cases We performed open reduction in six cases because of initial misdiagnosis or because of difficulty in satisfactory closed reduction We speculated that this complication is due to avascular necrosis of the distal end of the humerus, and that fracture-separation of the distal end of the humerus is more common than reported
33 citations
TL;DR: Three compounds isolated from the rhizomes of Davallia mariesii MOORE showed an inhibitory effect toward protein kinase C, and detailed analyses of their 1H- and 13C-nuclear magnetic resonance spectra were carried out by the use of two-dimensional nuclear magnetic resonance techniques.
Abstract: Procyanidin B-5 (1), epicatechin-(4β→8)-epicatechin-(4β→6)-epicatechin (2), and epicatechin-(4β→6)-epicatechin-(4β→8)-epicatechin-(4β→6)-epicatechin (3), which showed an inhibitory effect toward protein kinase C, were isolated from the rhizomes of Davallia mariesii MOORE. Detailed analyses of their 1H- and 13C-nuclear magnetic resonance spectra were carried out by the use of two-dimensional nuclear magnetic resonance techniques.
30 citations
TL;DR: The structures of the new compounds (1, 6, and 7) were determined by means of spectroscopic methods including two-dimensional nuclear magnetic resonance techniques as discussed by the authors, and the structure of the five known compounds (2, 3, 4, 5, 7, 7-dihydroxychromone-7-O-β-D-glucuronide methyl ester (6), and a novel norcarotane sesquiterpene glucoside named marioside (7, 8, 9, 10, 11, 12, 14,
Abstract: Three new compounds, (-)-epicatechin-5-O-β-D-glulcopyranodside (1), 5, 7-dihydroxychromone-7-O-β-D-glucuronide methyl ester (6), and a novel norcarotane sesquiterpene glucoside named marioside (7), have been isolated from the rhizomes of Davallia mariesii MOORE together with five known compounds, (-)-epicatechin-3-O-β-D-allopyranoside (2), coumaric acid-4-O-β-D-glucopyranoside (3), caffeic acid-4-O-β-D-glucopyranoside (4), vanillic acid-4-O-β-D-glucopyranoside (5), and L-tryptophan (8). The structures of the new compounds (1, 6, and 7) were determined by means of spectroscopic methods including two-dimensional nuclear magnetic resonance techniques.
29 citations
TL;DR: In this paper, the ab initio effective valence shell Hamiltonian method is generalized to calculate molecular properties as well as the valence state energies, and the procedure requires the evaluation of effective operators for each molecular property.
29 citations
TL;DR: In this paper, the effect of ionic content and butanediol (BD) on the state of dispersion and physical properties of emulsion-cast film was determined using Autosizer, transmission electron microscopy (TEM), Instron, and Rheovibron.
Abstract: Segmented polyurethane (PU) ionomers were prepared from cycloaliphatic diisocyanate [methylene bis(4-cyclohexyl isocyanate) (H12MDI) and isophoron diisocyanate (IPDI)] and polytetramethylene glycol (PTMG) by using an anionic-type chain extender, viz., dimethylol propionic acid (DMPA). The effect of ionic content and butanediol (BD) on the state of dispersion and physical properties of emulsion-cast film was determined using Autosizer, transmission electron microscopy (TEM), Instron, and Rheovibron. With increased incorporations of DMPA in PU, particle size of emulsion decreased asymptotically, tensile modulus and strength increased, and the glass transition temperature (T g) moved toward the higher temperature. On the other hand, with increased incorporation of BD in PU, particle size of emulsion, tensile modulus, and strength of the emulsion cast film increased, and the major transition of soft segment moved toward higher temperature. With regard to the structural effect of the isocyanate, H12MD...
TL;DR: In this article, the second-order ab initio effective valence shell Hamiltonian of quasi-degenerate many-body perturbation theory was used to determine the valence state potential energy curves of SH and SH +.
TL;DR: Anilines were easily diazotized and efficiently converted to aryl halides in an one-pot reaction using sodium nitrite and halotrimethylsilane in carbon tetrachloride.
TL;DR: In this article, aqueous dispersions of polyurethane (PU) ionomers were prepared from hydrogenated diphenylmethane diisocyanate (H12MDI), poly(tetramethylene adipate) glycol (PTAd), bisphenol A propylene oxide ether glycol(LER), and dimethylol propionic acid (DMPA) as potential ionic centres.
Abstract: Aqueous dispersions of polyurethane (PU) ionomers were prepared from hydrogenated diphenylmethane diisocyanate (H12MDI), poly(tetramethylene adipate) glycol (PTAd), bisphenol A propylene oxide ether glycol (LER), and dimethylol propionic acid (DMPA) as potential ionic centres. The urethaneforming reaction was carried out in N-methyl-2-pyrrolidone (NMP) with dibutyltin dilaurate (DBT) as catalyst. The effects of DMPA and bisphenol A polyol on the particle size of the dispersions, and the physical properties of the emulsion cast films were determined. It was found that the particle size decreased with DMPA, and increased with bisphenol A polyol contents. Initial modulus and tensile strength of the emulsion cast films increased, and the elongation at break decreased with DMPA and bisphenol A polyol contents. The results were interpreted in terms of increased interchain Coulombic forces and urethane linkages with DMPA, and increased chain rigidity of PU with bisphenol A polyol incorporation.
TL;DR: In this article, the authors used hydrographic and climatic data for the Bransfield Strait in Antarctica to infer clay mineral provenance and dispersal patterns, and found that the distribution of the surface sediments of the bransfield strait exhibits distinctive geographical distributions.
Abstract: Clay minerals of the surface sediments of Bransfield Strait, Antarctica, exhibit distinctive geographical distributions: kaolinite has the highest concentration near the shore of the South Shetland Islands in the northern strait (20%); chlorite, near Smith Island in the northwestern strait; illite, on the continental shelf off the Antarctic Peninsula in the southern strait (80%); and smectite, close to the Penguin and Bridgeman islands in the northeastern strait (25%). This distribution pattern, combined with hydrographic and climatic data for the strait, are used to infer clay mineral provenance and dispersal patterns.
TL;DR: The frequency dependent a.c. conductivity in KTiOPO 4 single crystal, in the range from 10 Hz to 100 kHz, has been measured as a function of temperature between 200°C and 700°C.
TL;DR: A simplified chiral recognition mechanism involving face-to-edge π-π interaction was proposed in this article to account for chromatographic data previously rationalized by invoking two competing, opposite sense chirality recognition mechanisms.
TL;DR: In this article, the effects of peroxide(1,3-bis(t-butyl-peroxy-isopropyl)benzene) and coagent [pentaerythritol triacrylate (PETA), triallyl isocyanurate (TAIC)] alone and together, were studied with regard to the thermal, mechanical, and rheological properties.
TL;DR: The relationship between dietary intake and the frequency of cardiovascular disease in Japan during the 20th century is reviewed.
Abstract: The relationship between dietary intake and the frequency of cardiovascular disease in Japan during the 20th century is reviewed.
TL;DR: Selenium dioxide is depolymerized and activated by trimethylsilyl polyphosphate in carbon tetrachloride as mentioned in this paper, which effectively aromatizes substituted cyclohexenes and cycloenadienes under mild reaction conditions.
TL;DR: In this article, 1-(2-carbomethoxyacrylyloyl)-5-fluorouracil (CMA-FU) was synthesized from 2,4-bis(trimethylsilyloxy)-5fluoropyrimidine (BTMSF) and poly(MAOEFU) was obtained by radical polymerization with 2,2′-azobisisobutyronitrile (AIBN) in cyclohexanone at 60°C.
Abstract: The monomers 1-(2-carbomethoxyacryloyl)-5-fluorouracil (CMA-FU) and 1-(methacryloyloxyethyl)-5-fluorouracil (MAOEFU) were synthesized from 2,4-bis(trimethylsilyloxy)-5-fluoropyrimidine (BTMSF). Poly(MAOEFU) was obtained by radical polymerization with 2,2′-azobisisobutyronitrile (AIBN) in cyclohexanone at 60°C. Copolymerizations of CMAFU or MAOEFU with methyl methacrylate (MMA) or styrene (St) were carried out with AIBN at 60°C. The copolymer compositions were analyzed by infrared (IR) spectroscopy for poly(CMAFU-co-St) and poly(CMAFU-co-MMA), or by ultraviolet (UV) spectroscopy for poly(MAOEFU-co-MMA), respectively. The monomer reactivity ratios r 1 and r 2 were determined by the Kelen-Tudos method: r 1 (CMAFU)=0.01 and r 2 (St)=7.46; r 1 (CMAFU)=0.01 and r 2 (MMA)=35.08; r 1 (MAOEFU)=0.77 and r 2 (MMA)=1.13. These values imply that the copolymerizations were significantly affected by the steric hindrances of monomers containing 5-fluorouracil (5-FU). Toxicity of the monomers and polymers synthes...
TL;DR: In this paper, an upper bound for the final-stage extrusion load and the deformed configuration for the three-dimensional backward extrusion of internally elliptic-shaped tubes from round billets is proposed.
TL;DR: This experimental carcinogenesis animal model allows the detailed quantitative and functional analysis of the infiltration of immunocompetent cells into epidermal tumors.
Abstract: We investigated the population and pattern of the infiltrated cells in both benign and malignant epidermal tumors which were induced chemically with benzo(a)pyrene (B(a)P) in murine skin. In benign papillomas, which were evolved by a two stage carcinogenesis regimen, a slight to mild inflammatory infiltration around the tumors was observed, and cells infiltrating into the tumor nests were rarely seen. In carcinomas, which were produced by a complete carcinogenesis regimen, a dense inflammatory infiltration was observed around the tumor nests. The infiltrated cells were characterized as T-lymphocytes, macrophages, and neutrophils. Natural killer (NK) cells were found around and in the tumor nests, but their number was small. Both T-lymphocytes and macrophages were found to invade the tumor nests in squamous cell carcinoma whose duration was more than four weeks. This experimental carcinogenesis animal model allows the detailed quantitative and functional analysis of the infiltration of immunocompetent cells into epidermal tumors.
TL;DR: The physiological genetic effect of MAOEFU and its polymers in Dro sophila melanogaster was investigated and it was found that MAO EFU, poly- (MAOEF U) and poly-co-MMA are considerably less effective than 5- fluorouracil.
Abstract: The monomer 1-(methacryloyloxyethyl)-5-fluorouracil (MAO EFU) was synthesized from 2,4-bis(trimethylsilyloxy)-5-fluoropyrimidine. Poly- (MAOEFU) and poly(MAOEFU-co-methyl methacrylate) were obtained by radical polymerization at 60°C. The monomer reactivity ratios, r1 and r2 were determined by the Kelen-Tudos method; r, (MAOEFU) = 0.77 and r2(MMA) = 1.13. The physiological genetic effect of MAOEFU and its polymers in Dro sophila melanogaster was investigated and found that MAOEFU, poly- (MAOEFU) and poly(MAOEFU-co-MMA) are considerably less effective than 5- fluorouracil.
TL;DR: Using the scanning method, for the first time extensive simulations of trails and self-avoiding walks terminally attached to an adsorbing linear boundary on a square lattice are carried out.
Abstract: Using the scanning method we carry out for the first time extensive simulations of trails and self-avoiding walks (SAWs) terminally attached to an adsorbing linear boundary on a square lattice. A bulk attraction energy is also defined for a self-intersection of a trail and a pair of nonbonded nearest-neighbor monomers of a SAW. The chains are simulated at the special point. Our critical exponents differ significantly from the exact values of Vanderzande, Stella, and Seno [Phys. Rev. Lett. 67, 2757 (1991)] for the \ensuremath{\theta}' model. Thus, their conjecture, that the \ensuremath{\theta} and \ensuremath{\theta}' points belong to the same universality class, is not supported.
TL;DR: Graft copolymerization of acrylonitrile (AN) and 4-chlorostyrene (4-Clst) onto EPDM was carried out using benzoyl peroxide as initiator.
Abstract: Graft copolymerization of acrylonitrile (AN) and 4-chlorostyrene (4-Clst) onto ethylene–propylene–diene terpolymer (EPDM) was carried out using benzoyl peroxide as initiator The effects of EPDM content, initiator concentration, solvent, mole ratio of 4-Clst to AN, reaction time, and reaction temperature on the graft copolymerization were examined It was found that the light resistance, weatherability, and thermal stability of the acrylonitrile–EPDM–4-chlorostyrene graft copolymer were considerably better than those of acrylonitrile–butadiene–styrene copolymer
TL;DR: In this article, the authors examined the growth of Cu2O on MgO substrates directly during deposition by sputtering, and observed a mosaic structure of the film may be related to the growth mechanism in which islands coalesce to form a continuous film.
Abstract: The epitaxial growth of Cu2O films is of significant interest for the unique potential they offer in the development of multilayer devices and superlattices. While fundamental studies may be carried out on epitaxial films prepared by any technique, the growth of artificially layered superlattices requires that films grow epitaxially during deposition. The present study examined the growth of Cu2O on MgO substrates directly during deposition by sputtering. Although epitaxial thin films of Cu2O could be produced, a mosaic structure was observed. The structure of the film may be related to the growth mechanism in which islands coalesce to form a continuous film.
TL;DR: In this paper, the effects of annealing and sample temperatures on the fluorescence properties of rhodamine 6G doped sol-gel glasses at low temperature were reported.