Showing papers by "Kyungpook National University published in 1993"
TL;DR: The water contact angle of the PMMA film was markedly decreased by oxygen plasma treatment, AA grafting or protein immobilization, indicating the increase of hydrophilicity of the surface-modified PMMA films.
146 citations
TL;DR: The patterns of disorder in this structure reveal important principles of protein structure and its dynamics, and suggests that co-ordinated motion extends in groups rather than simply as uncorrelated movement around an atom center.
120 citations
TL;DR: Cells of Saccharomyces cerevisiae (ATCC 24858) were encapsulated in the calcium alginate membrane and cultured and the dry cell concentration reached 309 g/L, which was much higher than could be obtained by cell entrapment.
Abstract: Cells of Saccharomyces cerevisiae (ATCC 24858) were encapsulated in the calcium alginate membrane and cultured. Swelling of the capsule was prevented by adding 0.2 g CaCl2 to 1 L growth medium. The dry cell concentration based on the inner volume of the capsule reached 309 g/L, which was much higher than could be obtained by cell entrapment. All the cells remained inside the capsule during the cultivation. The flux of CO2 through the capsule membrane increased approximately twice by adding a nonionic surfactant to the CaCl2 solution during the step of capsule formation.
60 citations
TL;DR: A cesium continuum that fills the channels and cavities of zeolite X has been prepared, and its structure has been determined by single-crystal x-ray crystallography.
Abstract: A cesium continuum that fills the channels and cavities of zeolite X has been prepared, and its structure has been determined by single-crystal x-ray crystallography. The three-dimensional continuum is cationic to balance the negative charge of the zeolite framework. Its valence electrons, only 0.3 per Cs(+) ion, are widely delocalized over 95 percent of the cesium ions in the crystal. The continuum has a unit cell formula of (Cs(122))(86+) and contains Cs(13) and Cs(14) clusters (one per supercage) arranged like the atoms in diamond, with one Cs(2) appendix (in the sodalite cavity) per cluster.
51 citations
TL;DR: Hypereosinophilic syndrome is a cause of focal hepatic lesions seen on sonograms, CT scans, or scintigrams, characterized by the varied appearance on the different types of images and the disappearance of the lesions with treatment.
Abstract: Hypereosinophilic syndrome (eosinophilia without demonstrable cause) commonly involves eosinophilic infiltration of the liver and spleen, but few reports have described the imaging findings. Accordingly, we reviewed the imaging findings in five patients with this syndrome in whom the liver was involved.Five patients who had hypereosinophilic syndrome with hepatic involvement were included in the study. The diagnosis of hepatic involvement was based on pathologic proof in two patients and on imaging and laboratory findings in the other three. Histologic examination of the hepatic lesions showed extensive eosinophilic infiltration in two patients and centrilobular necrosis in one. All patients had chest radiography, barium studies of the gastrointestinal tract, abdominal CT, and sonography. Four patients had hepatosplenic scintigraphy. All patients were followed up for 4-24 months.All patients had mild to marked hepatomegaly with multiple focal lesions. Focal lesions were detected on sonograms in three pati...
46 citations
Journal Article•
TL;DR: Intravenously administered S-nitrosoglutathione reduced the blood pressure of anesthesized dogs and monkeys to the same extent and with essentially the same rapid onset and dissipation as sodium nitroprusside, which is the fastest-acting of those vasodilators.
Abstract: S-Nitrosoglutathione, a possible intermediate in the pharmacological mechanisms of many vasodilators, undergoes hemolysis at pH 7.4 and 37 degrees C to give oxidized glutathione and nitric oxide with a second-order rate constant of approximately 3 x 10(-4) M-1sec-1. At the dosages normally employed, this reaction is, therefore, too slow to be an obligatory step in the pharmacological mechanisms of those, usually, fast-acting drugs. Transfers of the nitroso moiety to another thiol or to certain hemoproteins are, however, both much faster and could be involved in those pharmacological mechanisms. Intravenously administered S-nitrosoglutathione reduced the blood pressure of anesthesized dogs and monkeys to the same extent and with essentially the same rapid onset and dissipation as sodium nitroprusside, which is the fastest-acting of those vasodilators.
37 citations
TL;DR: In this article, the thermal properties of poly(phenylene sulfide) (PPS) and its derivatives were investigated by differential scanning calorimetry and thermogravimetric analysis.
35 citations
TL;DR: In this article, the sensitivity of an SnO 2 (Rh) thick film with added Rh to CH 4 (1000 ppm) is about 90% at an operating temperature of 400 °C, which is higher than those of SNO 2 thick film devices with added Pt or Pd.
Abstract: SnO 2 (Rh) thick-film devices for detecting methane gas selectively have been prepared by the screen-printing technique, and their characteristics have been investigated. The sensitivity of an SnO 2 thick film with added Rh to CH 4 (1000 ppm) is about 90% at an operating temperature of 400 °C, which is higher than those of SnO 2 thick-film devices with added Pt or Pd.
33 citations
28 citations
Journal Article•
TL;DR: A historical cohort study of 6,913 individuals was undertaken to determine the associated with illness as discussed by the authors, and exposed subjects were reported to be phenol associated symptoms significantly higher than those in a nearby unexposed area (39.6% vs 9.4%).
Abstract: A accidental spills of phenol(100%) to the river Nakdong with subsequent contamination of the tap water fer about two million consumers in Taegu city of Korea were occurred in March 1991. A historical cohort study of 6,913 individuals was undertaken to determine the associated with illness. Population subjects were divided into two groups of exposed and unexposed. Exposed subjects were reported to be phenol associated symptoms significantly higher than those in a nearby unexposed area(39.6% vs 9.4%, p
26 citations
TL;DR: In this paper, the effect of various conditions on catalyst activity and isospecificity were examined, and it was found that aluminum carbinolate is formed during polymerization by reaction of triethyl aluminum cocatalyst with BC remaining in the prepared catalyst.
Abstract: Mg(OEt)2/benzoyl chloride (BC)/TiCl4 catalyst has been prepared by the chemical reaction method, and the chemical composition and X-ray structure of the catalyst were studied. The effect of various conditions on catalyst activity and isospecificity were also examined. With 13C-NMR analysis, it was found that aluminum carbinolate is formed during polymerization by reaction of triethyl aluminum cocatalyst with BC remaining in the prepared catalyst. The formed aluminum carbinolate acts as an additional donor to increase the isotactic index of polypropylene (PP). The morphology of the prepared catalyst and PP was also observed. © 1993 John Wiley & Sons, Inc.
01 Mar 1993
TL;DR: In this paper, the static and dynamic characteristics of a step-up nine-switch matrix convertor under the control strategy proposed by Venturini are analyzed fully by the recently presented circuit DQ transformation technique and signal flow graphs.
Abstract: The static and dynamic characteristics of a practicable step-up nine-switch matrix convertor under the control strategy proposed by Venturini are analysed fully by the recently presented circuit DQ transformation technique and signal flow graphs. The step-up nine-switch matrix convertor consists of nonideal voltage and current sources, such as occur in practical inductance and capacitance filters. Several static and dynamic features of the convertor, such as steady-state input/output voltage gain, input power factor and transient response, are predicted analytically and verified by computer simulations. The signal flow graph is adopted to solve the complex fourth-order equivalent convertor and thus the nine-switch matrix convertor is analysed fully in explicit form.
TL;DR: In this paper, a dry impregnation of powdered Zr(OH)4 with an aqueous solution of (NH4)2CrO4 was performed using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectrography (XPS), XRD, and differential thermal analysis (DTA).
Abstract: Chromium oxide/zirconia was prepared by dry impregnation of powdered Zr(OH)4 with an aqueous solution of (NH4)2CrO4. The characterization of prepared samples was performed using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and differential thermal analysis (DTA), and by measurement of the surface area. The addition of chromium oxide to zirconia shifted the transitions of ZrO2 from the amorphous to the tetragonal phase and from the tetragonal to the monoclinic phase to higher temperatures due to the strong interaction between chromium oxide and zirconia; and the specific surface area of the samples increased in proportion to the chromium-oxide content. Since the ZrO2 stabilizes supported chromium oxide, chromium oxide was well dispersed on the surface of zirconia, and α-Cr2O3 was only observed at calcination temperatures above 1173 K. Upon the addition of only small amounts of chromium oxide (1 wt % Cr) to ZrO2, both the acidity and acid strength of the samples increased remarkably, showing the presence of two kinds of acid sites on the surface of CrOx/ZrO2 (Bronsted and Lewis acid sites).
TL;DR: This work parameterizes pH processes with three parameters and identifies them with the relay feedback testing and proposes an on-line tuning method using the relay Feedback with hysteresis for easier implementation of nonlinear pH controllers.
Abstract: For easier implementation of nonlinear pH controllers, we propose an on-line tuning method using the relay feedback with hysteresis. Since just two or three parameters are sufficient to characterize pH processes for practical applications (Williams et al., 1990; Lee et al., 1992), we parameterize pH processes with three parameters and then identify them with the relay feedback testing. The relay feedback method is very popular in on-line tuning of PID controllers (Astrom and Hagglund, 1984; Seborg et al., 1989). This on-line tuning method would reduce the efforts to obtain titration curves with off-line experiments
TL;DR: In this article, the authors characterize approximate linearization to order m of a single input non-linear system in terms of the existence of an integrating factor of order m − 2, which is equivalent to the well-known condition that a system of vector fields be order m−1 involutive.
Abstract: We characterize approximate linearization to order m of a single input non-linear system in terms of the existence of an integrating factor to order m − 2, which is equivalent to the well-known condition that a system of vector fields be order m − 1 involutive. We present a constructive method to obtain the required transformation for approximate linearization, which results in substantial computational savings.
Seoul National University1, Kyungpook National University2, Keimyung University3, Pusan National University4, Soonchunhyang University5, Yonsei University6, Ewha Womans University7, Chonnam National University8, Chung-Ang University9, Chungnam National University10, Hallym University11, Hanyang University12
TL;DR: Treatment success, defined as a reduction in PASI score by at least 66%, was achieved in 76.9% of patients and the overall assessments of efficacy and tolerability by both the investigators and the patients were mostly ‘good’ or ‘very good’.
Abstract: The purpose of this study was to evaluate the efficacy of a low-dose cyclosporin therapy in psoriasis. In the multicentre study, carried out in Korea, 52 patients with moderate to severe psoriasis were treated with an initial dose of 2.5 mg/kg per day cyclosporin for 18 weeks. In 44 patients the dose was increased gradually up to 5 mg/kg per day according to the therapeutic response. Treatment success, defined as a reduction in PASI score by at least 66%, was achieved in 76.9% of patients. PASI scores reduced significantly from 20.0 to 5.4. Changes in systolic and diastolic blood pressure were not statistically significant. A 30% increase in serum creatinine in comparison with baseline was observed in five patients (9.6%) by the 18th week, but none of the patients showed an increase beyond the normal range. The overall assessments of efficacy and tolerability by both the investigators and the patients were mostly ‘good’ or ‘very good’. Our regimen of low-dose cyclosporin therapy (2.5 mg/kg per day initial...
TL;DR: The central axon of a primary afferent neuron that responded to light mechanical stimulation of the lower premolar teeth in a fast adapting fashion was intra-axonally injected with horseradish peroxidase in the cat.
TL;DR: In this article, the wear mechanism of high-speed steel coated with TiN by arc ion plating during sliding against alumina and AISI 52100 steel under lubricated conditions has been investigated experimentally.
Patent•
15 Apr 1993TL;DR: In this article, an ion senstive field effect transistor (ISFET) comping a source 1 and a drain 3 formed in a substrate, an ion sensitive gate 2 placed between the source and drain 3, a Pt electrode 6 formed on the ion sensitive film 4.
Abstract: A bio-sensor employs an ion senstive field effect transistor (ISFET) comping a source 1 and a drain 3 formed in a substrate, an ion sensitive gate 2 placed between the source 1 and drain 3, an ion sensitive film 4 formed on the ion sensing gate 2, an immobilized enzyme membrane 5 defined on the ion sensitive film 4 and, a Pt electrode 6 formed on the ion sensitive film 4. The sensor has a Pt eleletrode being capable of sensing all biological substances which generate H 2 O 2 in enzyme reaction, whereby having the high sensitivity and the rapid reaction time.
TL;DR: In this paper, the effect of hydrogen on polypropene polymerization was studied and the active sites of different isospecificities have different sensitivities to hydrogen transfer and that the more specific active sites are more sensitive to hydrogen.
TL;DR: In this article, an analysis method for the broadband rectangular microstrip antenna geometry using E-plane gap coupling is considered, and the return loss of the designed broadband antenna is computed theoretically and compared with experimental results for illustrating the usefulness of this method.
Abstract: An analysis method for the broadband rectangular microstrip antenna geometry using E-plane gap coupling is considered. The return loss of the designed broadband antenna is computed theoretically and compared with experimental results for illustrating the usefulness of this method.
Korea University1, University of California, Davis2, Louisiana State University3, Virginia Tech4, University of South Carolina5, University of Hawaii at Manoa6, Konan University7, University of Minnesota8, Niigata University9, University of Rochester10, Saga University11, Seoul National University12, Kyungpook National University13, Chuo University14, Saitama University15
TL;DR: In this paper, the third moment of the inclusive momentum distribution of particles within jets produced by e+e- annihilation at TRISTAN was studied and the QCD coupling strength alpha(s) was determined by fits to the prediction of the Next-to-Leading Logarithm Parton-Shower model.
TL;DR: In this article, the catalytic activities for the ethylene dimerization and polymerization were closely correlated with the acidity of the catalysts, and the polyethylene produced had a high melting point and density.
Abstract: Polymerization of ethylene over transition-metal exchanged montmorillonite (K 10) was studied at room temperature. It was found that over Ni2+ -Mont, dimerization of ethylene to n-butenes proceeded selectively. Over Cr3+-Mont, high polymerization occurred, and the polyethylene produced had a high melting point and density. The catalytic activities for the ethylene dimerization and polymerization were closely correlated with the acidity of the catalysts. The active sites for the ethylene dimerization consisted of nickel ion and Bronsted acid, while the active site for the polymerization was related to the Lewis acid, chromium ion.
28 Mar 1993
TL;DR: The authors present, for large scale TSPs, an efficient SOFM algorithm in which a winner neuron for each city is not duplicated but excluded in the next competition, which can obtain better solutions.
Abstract: Kohonen's self-organizing feature map (SOFM) has the topological characteristics that can be effectively used in solving traveling salesman problems (TSPs). B. Angeniol et al. (1988) applied SOFM in solving TSPs, but, due to the duplication of a new neuron as the winner for two different cities, their algorithm requires at least kN output neurons and 2 kN connections for N-city TSPs, where k is the number of the deletion process. The authors present, for large scale TSPs, an efficient SOFM algorithm in which a winner neuron for each city is not duplicated but excluded in the next competition. Therefore, the algorithm requires just only the N output neurons and 2N connections for N-city TSPs. Due to direct use of the output potential, the proposed algorithm can obtain better solutions. Simulation results show about 30% faster convergence and better solutions than the conventional algorithm for solving 30-city TSPs. Other simulation results for large scale TSPs with 1000 cities also show good performance of the proposed algorithm. >
TL;DR: In this paper, Carriere's discompacte, a measure of noncompactness of affine groups acting on an affine space, was used to prove that an n-dimensional closed real projective manifold M is convex or affine.
Abstract: Suppose that an n-dimensional closed real projective manifold M, n ≥ 2, develops into an affine space RPn − RPn − 1 for an (n − 1)-dimensional subspace RPn − 1 of the projective space RPn. Then either M is convex or affine or M admits a flat foliation with a transverse invariant Hilbert metric. Further, if the codimension of is n − 1, then M is convex. We prove this statement by a use of a variation of Carriere's discompacte, a measure of non-compactedness of an affine group acting on an affine space.
14 Apr 1993
TL;DR: This paper presents an architecture and techniques to menage TCP/IP Internet using OSI's common management information services (CMIS) and system management functions (SMFs) and compares services provided by SNMP with those of OSI management.
Abstract: Network management refers to monitoring and controlling network elements. There are two different prevalent communication protocols used for network management, simple network management protocol (SNMP) proposed by IAB and common management information protocol (CMIP) by ISO/OSI. In this paper, we propose an efficient approach for the integration of OSI network management and TCP/IP Internet management using SNMP. We present an architecture and techniques to menage TCP/IP Internet using OSI's common management information services (CMIS) and system management functions (SMFs). We compare services provided by SNMP with those of OSI management. The features of management information models used by SNMP and OSI management are also comparatively analyzed. Software architecture and algorithms which are necessary for the provision of management application services using SNMP are presented. >
TL;DR: Cymbella orientalis Lee, sp.
Abstract: Cymbella orientalis Lee, sp. nov., collected from the Kwangchun River, Kyungsang Pukdo, Korea, is formally described. The new taxon is characterized by its dorsal unilateral central area and areolar structure with flaps. C. orientalis is an attached freshwater species found in springs, lakes and the lower course of rivers. It was recorded from several localities within the Far East: Okinawa and Kikai Islands in the Ryukyu Islands, Tsushima Island in Japan, Beijing and Shandong in China, and Taiwan.
TL;DR: Callus regeneration was observed from flower buds of Allium senescens var.
Abstract: Callus regeneration was observed from flower buds of Allium senescens var. minor inoculated in BDS, MS or B5 medium supplemented with 4.4 μM benzyladenine alone or in combination with 4.5 μM 2,4-dichlorophenoxy-acetic acid (2,4-d), with 2,4-d and kinetin (4.5 μM/4.6 μM) or with 5.3 μM naphthaleneacetic acid. Ovules enlarged initially but the embryogenic tissue degenerated as callus development progressed from the nectar regions of the petals. Shoot buds and leaf primordia developed from the meristematic protuberances that originated from the surface of the callus. BDS medium with 4.5 μM 2,4-d and 13.3 μM BA was most suitable for shoot multiplication. The regenerated shoots were rooted in respective liquid medium without any growth regulators and successfully transferred to soil with 90% survival rate.
TL;DR: There is significant congruence relationships between the information characteristics of AIS and the contextual variables (organizational structure and task characteristics), and the influence factors, such as user participation in the development process, top management support, capability of information systems personnel, and existence of steering committees are found.
Abstract: This paper represents an exploratory effort to test empirically the interactions among the influence factors, the contextual variables, and the information characteristics of accounting information systems (AIS) at the subunit level. In this study, we found that there are significant congruence relationships between the information characteristics of AIS and the contextual variables (organizational structure and task characteristics). Also, the influence factors, such as user participation in the development process, top management support, capability of information systems personnel, and existence of steering committees, have an effect on the relationships between the contextual variables and the information characteristics such as information scope and aggregation.