Showing papers by "Kyungpook National University published in 1994"
TL;DR: A large number of research groups have studied the interaction of biomedical materials with cultured cells to improve their tissue compatibility when the materials are implanted as substitutes for organs, skin, bone, etc.
383 citations
13 Nov 1994
TL;DR: The proposed method does not depend on line information of a plate it is very robust to boundary deformation and strong enough to deal with a car's image which has many similar regions with a plate.
Abstract: An automatic recognition method of a car license plate using color image processing is presented. At first, background colors of a plate are extracted from an input car image. A neural network is used for more stable extraction. To find a plate region, a fixed ratio of horizontal and vertical length of a plate is used. To recognize characters in a plate, template matching and postprocessing techniques are used. Since the proposed method does not depend on line information of a plate it is very robust to boundary deformation. Also, this method is strong enough to deal with a car's image which has many similar regions with a plate. >
198 citations
TL;DR: It is concluded that the gross amount of docosahexaenoic acid plays only a minor role in adjusting the membrane physical properties to temperature, and factors other than lipids might be involved in the adaptation processes.
Abstract: A comparison of the structural orders of membranes of a mixed brain-cell population isolated from Cyprinus carpio L. acclimated to either summer (23-25 degrees C) or winter (5 degrees C) revealed a high degree of compensation (80%) for temperature, as assayed by electron spin resonance spectroscopy. The cells rapidly forget their thermal history and adjust the physical properties of the membranes when shifted to the other extreme of temperature either in vivo or in vitro. Phospholipids separated from both types of animals exhibit only around 10% compensation. Arachidonic and docosahexaenoic acids are the major polyunsaturated fatty acids in the brains, but the fatty acid composition of the brain total phospholipids does not vary with adaptation to temperature. Separation of phosphatidylcholines and phosphatidylethanolamines into molecular species revealed a 2- to 3-fold accumulation of 18:1/22:6, 18:1/20:4, and 18:1/18:1 species in the latter; 18:0/22:6 showed an opposite tendency. Molecular species composition of phosphatidylcholines did not vary with the temperature. The same trends of changes were seen with brains of freshwater fish from subtropical (Catla catla L.) or boreal (Acerina cernua) regions. It is concluded that the gross amount of docosahexaenoic acid (22:6) plays only a minor role in adjusting the membrane physical properties to temperature. Factors other than lipids might be involved in the adaptation processes. Due to their specific molecular architecture, molecules such as 18:1/22:6, 18:1/20:4, or 18:1/18:1 phosphatidylethanolamine might prevent the contraction of membranes in the cold and may provide an environment for some other components involved in the temperature regulation of physical properties of nerve cell membranes.
116 citations
TL;DR: A microfracture mechanism of the dental resin composites containing spherically-shaped filler particles is proposed based on the results obtained from the AE-releasing pattern, two-dimensional AE location, and fracture surface findings.
Abstract: The effects of spherically-shaped filler particles on bending strength, bending elastic modulus, and fracture toughness of resin composites were studied. The filler content was changed by 0, 20, 40, 60, and 70 wt%. Bending properties and fracture toughnesses were determined on three-point bending specimens. Acoustic Emission (AE), i.e., the elastic wave released from a localized source in the material, was detected by sensors of a high-sensitivity and low-noise resonance type during the fracture toughness test. Detected acoustic emission signals were analyzed for parameters such as amplitude, events, and locations. The fractured surf ace was examined by a scanning electron microscope.The bending strength and the fracture toughness showed almost the same trend in their increasing rates by filler content, but the elastic modulus showed a much higher increasing rate. A microfracture mechanism of the dental resin composites containing spherically-shaped filler particles is proposed based on the results obtain...
88 citations
TL;DR: Interestingly, unlike irreversible protein aggregates, the insulin powders recover essentially full biological activity on reconstitution, and are suggestive of extensive beta-sheet-mediated intermolecular interactions in precipitate states, consistent with analyses of irreversible protein aggregate/fibril states.
80 citations
TL;DR: In this article, a silicon-based SnO 2 gas sensor has been fabricated for monitoring liquified petroleum gas (LPG), commonly used as town gas, which is made by silicon IC technology together with SnO f2 thin-film processing.
Abstract: A silicon-based SnO 2 gas sensor has been fabricated for monitoring liquified petroleum gas (LPG), commonly used as town gas. The gas sensor is made by silicon IC technology together with SnO f2 thin-film processing. The whole chip with a size of 9 mm x 9 mm consists of nine sensors (three by three array). each sensor is supported by a thin membrane of SiO 2 /Si 3 N 4 /SiO 2 layers that provides a low thermal mass and prevents heat conduction through the surrounding substrate material. Tin oxide thin film is prepared by thermal evaporation of metallic tin granules and subsequent thermal oxidation of the metallic film at 600 °C. To form the SnO 2 (Pt) thin film, a layer of Pt with a thickness of several tens of angstroms is sputtered onto the tin oxide film and heat treated at 500 °C in air for several hours in order to stabilize its electrical response. The fabricated SnO 2 (Pt) microsensors exhibit about 85 and 92% sensitivities to 5000 ppm C 3 H 8 and 5000 ppm C 4 H 10 (the main components of LPG) at 250 °C, respectively, and show a rapid response time of less than 5 s.
72 citations
TL;DR: The predicted estimates of the target angles are updated by the most recent output of the sensor array to improve the tracking performance of the algorithm for crossing targets and the least square solution is modified to avoid abnormally large angular innovations when the targets are very close.
Abstract: We modify a multiple target angle tracking algorithm presented by Sword, et al. (1990). The predicted estimates, instead of the existing estimates, of the target angles are updated by the most recent output of the sensor array to improve the tracking performance of the algorithm for crossing targets. Also, the least square solution is modified to avoid abnormally large angular innovations when the target angles are very close. The improved performance of the proposed algorithm is demonstrated by computer simulations. >
43 citations
Journal Article•
TL;DR: Thallium biokinetics are different during pharmacologic stress testing with adenosine, dipyridamole and dobutamine than during exercise, and Diagnostic criteria for quantitative analysis of myocardial perfusion imaging must therefore be specific for the type of stress used.
Abstract: UNLABELLED There are currently four common types of stress used with thallium-201 imaging in the diagnosis of coronary artery disease and risk assessment. The objective of this study was to examine the thallium biokinetics during exercise, adenosine, dipyridamole and dobutamine stress testing in 15 healthy volunteers. METHODS Each subject underwent planar 201Tl imaging during maximal treadmill exercise testing, adenosine infusion (140 micrograms/kg/min for 6 min), dipyridamole infusion (142 micrograms/kg/min for 4 min) and dobutamine infusion (40 micrograms/kg/min). RESULTS Absolute myocardial thallium activity was greater after pharmacologic testing than exercise, (p < 0.001 each). Thus, the activity was 505 counts/pixel with adenosine, 491 counts/pixel with dipyridamole, 517 counts/pixel with dobutamine and 409 counts/pixel with exercise. The myocardial thallium clearance was lower with pharmacologic testing than exercise; 9.7%/hr with adenosine, 9.9%/hr with dipyridamole, 11.3%/hr with dobutamine and 13%/hr with exercise (p < 0.01 each). The thallium uptake and clearance in the lung and liver were also greater with pharmacologic stress testing than exercise (p < 0.05). CONCLUSIONS Thus, thallium biokinetics are different during pharmacologic stress testing with adenosine, dipyridamole and dobutamine than during exercise. Diagnostic criteria for quantitative analysis of myocardial perfusion imaging must therefore be specific for the type of stress used.
42 citations
TL;DR: An approach using a Hopfield neural network to the stereo correspondence problem for extracting the 3D structure of a scene by transforming constraints into an energy function, whose minimum value corresponds to the best solution of the problem, on the Hopfield network.
42 citations
University of Rochester1, 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, Rutgers University10, Saga University11, Korea University12, Seoul National University13, Kyungpook National University14, Chuo University15, Saitama University16
TL;DR: In this paper, the authors present cross section measurements for inclusive jet production in almost real photon-photon interactions at TRISTAN using the AMY detector, compared with leading-order QCD calculations for different parameterizations of the parton density in the photon.
37 citations
TL;DR: In this paper, a series of TiO2-SiO2 catalysts were prepared by coprecipitation from the mixed solution of titanium tetrachloride and sodium silicate.
TL;DR: In this article, a study of the reaction π − p → ƒ 1 (1285) π− p at 18 GeV / c, with ǫ 1 ( 1285) → K + K 0 π- This reaction is almost entirely mediated by the natural-parity exchange, presumably à 2 (1270 or ϱ exchange.
TL;DR: Simulation results show that the proposed nonlinear self-tuning regulator for controlling the pH value of weak acid streams by a strong base provides good performance for realistic situations such as multicomponent weak acid and strong base systems.
TL;DR: The authors have performed one-stage penile reconstruction in five patients since 1989, using an innervated radial forearm osteocutaneous flap, and all patients showed aesthetically acceptable results and good sensory recovery.
Abstract: Reconstruction of the penis may be indicated in cases of traumatic or surgical amputation of the penis, congenital absence of the penis, micropenis, male pseudohermaphroditism, or transsexualism. Despite recent advances in microsurgery, which have improved the results of total penile reconstructions to a great extent, this operation remains one of the biggest challenges to reconstructive plastic surgeons. The authors have performed one-stage penile reconstruction in five patients since 1989, using an innervated radial forearm osteocutaneous flap. At follow-up (up to 46 months), all patients showed aesthetically acceptable results and good sensory recovery. The most common complications were related to the urethra, involving two fistulae and one urethral stricture.
TL;DR: In this article, a non-dimensional parameter, S cf, is proposed to estimate the wear rate of ceramics and is defined as S cf = P√(1+μ 2 )a K IC S cf is given as a function of normal pressure, fracture toughness of materials, crack length (the degree of surface defect of materials) and friction coefficient in the contact region.
TL;DR: In this article, the α-cyclodextrine (CD) is shown to be a prospective organic support for polymerization catalysts of olefins, and it was shown that the polyethylene (PE) polymerization could be initiated even with ordinary trialkylaluminium and the thermal properties of PE were improved.
Abstract: It is shown that α-cyclodextrine (CD) is a prospective organic support for polymerization catalysts of olefins. By supporting methylaluminoxane, trimethylaluminium and Cp 2 ZrCl 2 on CD separately or successively, the ethylene polymerization could be initiated even with ordinary trialkylaluminium and the thermal properties of PE were improved
TL;DR: The results suggest that degradation and invasion of brain basement membrane and responses to paracrine neurotrophins andParacrine transferrins are important properties in brain metastasis of murine and human malignant melanoma cells.
Abstract: Mouse and human melanoma cells metastatic to the brain express degradative enzyme activities that are used for invasion of brain basement membrane and parenchyma. Compared to poorly metastatic or lung- or ovary-metastatic murine melanoma lines, the brain-metastatic sublines secreted higher levels of a variety of degradative enzymes. Brain-metastatic murine and human melanoma cells also degraded subendothelial basement membrane and reconstituted basement membrane at rates higher than other metastatic melanoma cells. In some cases these degradative activities in mouse and human melanoma cells can be induced by paracrine factors known to be present in the brain parenchyma, such as nerve growth factor (NGF). NGF stimulates the expression of degradative enzymes, such as the endo-Β-glucuronidase heparanase, that are important in basement membrane penetration but this factor does not stimulate melanoma cell growth. The growth of brain-metastasizing melanoma cells appears to be stimulated by other paracrine growth factors, such as paracrine transferrin. Melanoma cells metastatic to brain express higher numbers of transferrin receptors and respond and proliferate at lower concentrations of transferrin than do melanoma cells metastatic to other sites or poorly metastatic melanoma cells. The results suggest that degradation and invasion of brain basement membrane and responses to paracrine neurotrophins and paracrine transferrins are important properties in brain metastasis of murine and human malignant melanoma cells.
12 Jun 1994
TL;DR: The authors investigate burst-level bandwidth reservation schemes in ATM LANs and compare the performance of REQ/ACK and on-the-fly reservation schemes for a client-server model with a single ATM switch and derive an analytical model for the mean burst transfer delay, blocking probability and throughput.
Abstract: The authors investigate burst-level bandwidth reservation schemes in ATM LANs and compare the performance of REQ/ACK and on-the-fly reservation schemes for a client-server model with a single ATM switch. To compare performance, they derive an analytical model for the mean burst transfer delay, blocking probability and throughput. They discuss the dependence of these performance parameters on the propagation delay-to-burst duration ratio and peak rate-to-link speed ratio. They show that, for moderate propagation delay-to-burst duration ratio, the on-the-fly scheme is more desirable since the REQ/ACK scheme has limited achievable throughput for fast reservation traffic due to unused bandwidth during the REQ-ACK cycle. Also, for a given burst length (in bits), the delay performance of REQ/ACK scheme is more sensitive to increase in the peak rate than the on-the-fly scheme. >
TL;DR: In this article, a new control scheme named optimum quantum sequence control (OQSC) was proposed, which always minimizes the output voltage ripple of the quantum series resonant converter (QSRC) for all possible sequences.
Abstract: A new control scheme named optimum quantum sequence control (OQSC) which always minimizes the output voltage ripple of the quantum series resonant converter (QSRC) for all possible sequences is proposed. This control scheme is so general that it is irrelevant to all circuit conditions such as magnitudes of circuit elements as well as input/output voltage so far as it is operating in the continuous conduction mode (CCM). Furthermore, the dynamic range of QSRC is much extended by the OQSC. This feature is verified by simulations and experiments with good agreements. >
TL;DR: An accidental spill of phenol into the Nakdong river with subsequent contamination of the tap water for about two million consumers in Teagu city of Korea occurred in March 1991 and a historical cohort study of 6,913 individuals was undertaken to determine association with illness.
Abstract: An accidental spill of phenol (100%) into the Nakdong river with subsequent contamination of the tap water for about two million consumers in Teagu city of Korea occurred in March 1991. A historical cohort study of 6,913 individuals was undertaken to determine association with illness. Population subjects were divided into two groups of exposed and unexposed. Exposed subjects were reported to have significantly more phenol associated symptoms than those in a nearby unexposed area (39.6% vs. 9.4%, p < 0.01). Especially, in the related symptoms, highly significant differences were noted in the number of subjects reporting gastrointestinal illness such as nausea, vomiting, diarrhea, or abdominal pain. During the accident, study subjects who experienced peculiar taste or odor in the tap water were significantly more in the exposed areas (92% vs. 34.3%).
02 Oct 1994
TL;DR: In this paper, a simple and exact measurement method of rotor resistance and rotor time constant of induction motor is proposed, where a DC current is injected to the magnetizing inductance, and then magnetizing current is discharged to the rotor, so that the voltage is taken at the stator.
Abstract: Rotor time constant is essential for high performance motor control in the induction motor. A simple and exact measurement method of rotor resistance and rotor time constant of induction motor is proposed. A DC current is injected to the magnetizing inductance, and then the magnetizing current is discharged to the rotor, so that the voltage is taken at the stator. Then the measured stator voltage has information of rotor time constant as a function of magnetizing current. In this paper, rotor time constant obtained from conventional method and the proposed method are compared. The accuracy of the measurement is tested with a vector controller by a linear relation between the input torque command and output torque at steady state. >
TL;DR: In this article, the application of some polymers as nucleating agents for polypropylene has been examined and it was found that polycyclopentene was a superior nucleating agent to typical organic nucleiating agents.
Abstract: The application of some polymers as nucleating agents for polypropylene has been examined. Among various polymeric nucleating agents, polycyclopentene was found to be a superior nucleating agent to typical organic nucleating agents. When polycyclopentene was added to polypropylene, the crystallization temperature and the degree of crystallinity of polypropylene increased. In addition, the crystallization rate and the number of spherulites increased whereas the size of spherulites decreased remarkably. As a result of polycyclopentene addition, the transparency of polypropylene film could be improved considerably. © 1994 John Wiley & Sons, Inc.
TL;DR: In this article, a temperature stable high dielectric ceramic capacitor was made by compositional fluctuation control, which showed the most temperature stable characteristic at the composition of 0.5:0.3 volume fraction when the mixing method is parallel.
Abstract: In this study, a temperature stable high dielectric ceramic capacitor was made by compositional fluctuation control. Dielectric property was examined by controlling mixing method and volume fraction of PMN, 0.9PMN-0.1PT, and 0.8PMN-0.2PT, each of which is the relaxor material of-10°C, 50°C, and 100°C maximum of dielectric constant respectively. It shows the most temperature stable characteristic at the composition of 0.5:0.2:0.3 volume fraction when the mixing method is parallel. And it shows flat dielectric constant of 10,000 in the range of-10°C to 100°C.
TL;DR: The positions of Xe atoms encapsulated in the cavities of fully dehydrated zeolite A of unit-cell composition Cs3Na8HSi12Al12O48 (Cs3-A) have been determined as mentioned in this paper.
Abstract: The positions of Xe atoms encapsulated in the cavities of fully dehydrated zeolite A of unit-cell composition Cs3Na8HSi12Al12O48 (Cs3-A) have been determined. Cs3-A was exposed to 255 atm of xenon at 400 °C for 7 days, followed by cooling at pressure to encapsulate Xe atoms; a second crystal was treated similarly at 450 atm, and a third at 1020 atm. The resulting crystal structures of Cs3-A(2.5Xe) (crystal 1, a = 12.245(2) A, R1 = 0.056, R2 = 0.059), Cs3-A(4.5Xe) (crystal 2, a = 12.258(2) A, R1 = 0.061, R2 = 0.058), and Cs3-A(5.25Xe) (crystal 3, a = 12.236(2) A, R1 = 0.061, R2 = 0.057) were determined by single-crystal X-ray diffraction techniques in the cubic space group Pm3m at 21(1) °C and 1 atm. The approximately 2.5, 4.5, and 5.25 Xe atoms per unit cell, respectively, are distributed over three crystallographically distinct positions. At the center of each sodalite unit in crystals 1, 2, and 3, respectively, are 0.5, 0.75, and 0.75 Xe atoms at Xe(1); in addition, off center in crystal 3 are 0.25 Xe a...
TL;DR: An efficient parallel algorithm to solve the single function coarsest partition problem and efficient parallel algorithms to find a minimal starting point of a circular string with respect to lexicographic ordering and to sort lexicographically a list of strings of different lengths are presented.
TL;DR: In this paper, a simple simulative test was developed to evaluate the stamping formability of steel sheets in plane strain stretching deformation, which was evaluated by the limiting punch height (LPH) value in the plane strain punch stretching (PSS) test.
Abstract: A simple simulative test was developed to evaluate the stamping formability of steel sheets in plane strain stretching deformation. The stamping formability was evaluated by the limiting punch height (LPH) value in the plane strain punch stretching (PSS) test compared to the minimum of the limiting dome height (LDHo) value in the hemispherical punch stretching test, the standard LDH test. The PSS test shows a stable plane strain deformation and a good reproducibility with less scattering data. Moreover, the LPH value in the PSS test ranks well the stamping formability of various sheet materials and shows good correlations with press performance.
TL;DR: In this article, the compatibilizing effect of polyarylate-polystyrene (PAR-PS) block copolymer prepared from macro-zoom initiator was examined.
Abstract: The compatibilizing effect of polyarylate-polystyrene (PAR-PS) block copolymer prepared from macroazo initiator was examined in polyarylate/polystyrene blends from the view-points of morphology, density, and thermal, mechanical, and rheological properties. PARPS block copolymer enhanced the mutual dissolution of the homopolymers. Reduced dispersed-domain size and increased density showed the efficiency of the block copolymer as a compatibilizing agent. Results from mechanical and rheological properties could also be explained by the compatibilizing effect of PAR-PS block copolymer in the blends. © 1994 John Wiley & Sons, Inc.
TL;DR: In this paper, the aqueous acetonitrile solution of N-benzyl-2-chloroaniline was cyclized and reduced to give phenanthridine, 5,5′, 6,6, 6′-tetrahydro-6,6′-biphenanthridyl, and bibenzyl.
Patent•
07 Oct 1994TL;DR: A mass manufacturing method of semiconductor acceleration and vibration sensors uses a dispensing method, a electrical plating method, or a screen-printing method or a preforming method in manufacturing a mass made of metal pastes in a desired size and amount on a mass pad of a thin metal film which is formed on a beam in a given pattern, so that it can be adapted to the mass-production of the sensors having the desired amount and size as mentioned in this paper.
Abstract: A mass manufacturing method of semiconductor acceleration and vibration sensors uses a dispensing method, a electrical plating method, a screen-printing method or a preforming method in manufacturing a mass made of metal pastes in a desired size and amount on a mass pad of a thin metal film which is formed on a beam in a given pattern, so that it can be adapted to the mass-production of the sensors having the mass of the desired amount and size.
Louisiana State University1, University of California, Davis2, Virginia Tech3, University of South Carolina4, University of Hawaii at Manoa5, Konan University6, University of Minnesota7, Niigata University8, Rutgers University9, University of Rochester10, Saga University11, Korea University12, Seoul National University13, Kyungpook National University14, Chuo University15, Saitama University16
TL;DR: Using 773 muons found in hadronic events from 142 pb-1 of data at a c.m. energy of 57.8 GeV, the cross section and forward-backward charge asymmetry for the e+e- --> bbBAR process, and the heavy quark fragmentation function parameters for the Peterson model are extracted.
Abstract: Using 773 muons found in hadronic events from 142 pb-1 of data at a c.m. energy of 57.8 GeV, we extract the cross section and forward-backward charge asymmetry for the e+e- --> bbBAR process, and the heavy quark fragmentation function parameters for the Peterson model. For the analysis of the e+e- --> bbBAR process, we use a method in which the behavior of the c quark and lighter quarks is assumed, with only that of the b quark left indeterminate. The cross section and asymmetry for e+e- --> bbBAR are found to be R(b) = 0.57 +/- 0.06(stat) +/- 0.08(syst) and A(b) = -0.59 +/- 0.09 +/- 0.09, respectively. They are consistent with the standard model predictions. For the study of the fragmentation function we use the variable [x(e)], the fraction of the beam energy carried by the heavy hadrons. We obtain [x(E)]c = 0.56(-0.05-0.03)+0.04+0.03 and [x(E)]b = 0.65(-0.04-0.06)+0.06+0.05, respectively. These are in good agreement with previously measured values.