• Proceedings of the Korea Water Resources Association Conference
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• 1997.05a
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• pp.192-198
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• 1997

The spatial variation of saturation tendency can be calculated from the Digital Elevation Model (DEM) employing the multiple flow direction algorithm on the platform of Geographic Resources Support Analysis System (GRASS). It is expected that a bettter understanding of dynamical runoff processes in hillslope hydrological scale is obtained through tracing various runoff path such as infiltration excess overland flow component, strutation excess overland flow component and subsurface runoff component. A procedure is suggested to consider the effect of a tile system on calculating the topographic index. A small agricultural subwatershed (3.4 km2) is used for this study.

• Journal of Soil and Groundwater Environment
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• v.6 no.2
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• pp.69-81
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• 2001

The constitutive relation among capillary pressure, saturation and relative permeability should be predetermined in order to simulate immiscible water-gas flow in porous media. The relation between saturation and relative permeability becomes more important when the capillary force can be disregarded and viscous friction force governs the flow. In this study, a 2-dimensional finite difference numerical model was developed, in which the variation of viscosity with pressure and that of relative permeability with water saturation can be treated. Seven cases of parallel plate tests were performed in order to obtain the characteristic equation of relative permeability which would be used in. the developed numerical model. It was not possible, however, to match the curves of relative permeability from the plate tests with the existing emperical models. Consequently a logistic equation was proposed as a new emperical model. As this model was composed of the parameter involving aperture size, any aperture size of fracture can be applied to the model. For the purpose of verification, the characteristic equation of relative permeability was applied to the developed numerical model and the computed results were compared with those of plate test. As a result of application of numerical model, in order to check the field applicability, to single fracture surrounding an underground storage cavern, the simultaneous flow of water and propane gas was able to be simulated properly by the model.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.155-162
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• 2003

The soil-water characteristic curve (SWCC) represents the essential constitutive relationship for solving various problems in unsaturated soil mechanics. A reliable and convenient experimental method is needed for the determination of the SWCC in engineering applications. This study introduces and proves that the suction-saturation experimental measurement based on the flow pump technique is a convenient and accurate method for obtaining the SWCC. The flow pump technique provides complete control over the test conditions and is capable of detecting all the important elements of the SWCC. In particular, it is capable of defining continuous drying and wetting curves, the moment of air occlusion, and the hysteretic behavior of unsaturated soils. Not only the optimal testing procedure but also the analysis technique for the flow pump technique has been established in this study. Especially, the method of the suction drop measurement was developed to measure the SWCC. This method is a convenient and time saving method without losing accuracy.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.197.2-197.2
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• 2011

Preliminary analysis on the modeling conditions and the simulation results is conducted only to evaluate the correctness of the simulation configuration further to apply for the LASGIT project. Except for the unrealistic modeling conditions for the relations of capillary pressure and relative permeability against water saturation used previously, the simulation results successfully demonstrate Helium propagation typical for two-phase flow. Further elaborated simulation with more realistic parameters should complete the weak points of the preliminary work.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.4
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• pp.301-306
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• 1992

In order to determine the optimal conditions for the process of acetic acid fermentation, the kinetics of Acetobacter aceti fermentation in submerged batch cultures were studied at different agitation speeds and air flow rates. The maximum cell concentration was noted after about 48 hr fermentation and the time course of Acetobactey aceti fermentation showed a distinct feature of growth-associated product formation. At agitation speeds 700, 500, and 300 rpm fixed on air flow rate 1 v/v/M, specific grow rates were $3.97\times10^{-2},\;3.82\times10^{-2},\;and\;2.04\times10^{-2\} \;hr^{-1}$, saturation constants were 61.4, 64.6, and 69.4mg/ml. and volumetric oxygen transfer coefficients were 0.9337, 0.4468, and 0.1701 $min^{-1},$ respectively. At air flow rates 1.25, 1.00, and 0.75 v/v/M fixed on agitation speed 500 rpm, specific growth rates were $3.90\times10^{-2},\;3.82\times10^{-2},\;and\;2.37\times10^{-2}\;hr^{-1}$, saturation constants were 63.4, 64.6, and 64.9 mg/ml, and volumetric oxygen transfer coefficient were 0.4923, 0.4468, and 0.3509 $min^{-1},$ respectively.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.505-509
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• 2013

Background The aim of this study was to collect important data on the time of oxygen saturation change in relation to skin flap color alteration using non-invasive pulse oximetry to evaluate its ability to provide continuous monitoring of skin flap perfusion. Methods An experimental study on the monitoring of blood perfusion of 20 tube-island groin flaps of 10 male New Zealand rabbits was performed using pulse oximetry. The animals were randomly assigned to one of two groups representing a blockage of either arterial or venous blood flow. The oxygen saturation change and clinical color alteration were monitored from the beginning of vessel clamping until the saturation became undetectable. The result was analyzed by the t-test using SSPS ver. 10.0. Results The mean times from the vessel clamping until the saturation became undetectable were $20.19{\pm}2.13$ seconds and $74.91{\pm}10.57$ seconds for the artery and vein clamping groups, respectively. The mean time of the clinical alteration from the beginning of vein clamping was $34.5{\pm}11.72$ minutes, while the alteration in flaps with artery clamping could not be detected until 2.5 hours after clamping. Conclusions The use of neonate-type reusable flex sensor-pulse oximetry is objective and effective in early detection of arterial and vein blockage. It provides real-time data on vessel occlusion, which in turn will allow for early salvaging. The detection periods of both arterial occlusion and venous congestion are much earlier than the color alteration one may encounter clinically.

• Geomechanics and Engineering
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• v.23 no.1
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• pp.85-92
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• 2020

This study adopted soil test and laboratory physical model experiments to simulate the tailings impoundment accumulation process according to the principle of similarity. Relying on the practical engineering, it analyzed the tailings deposition characteristics on dry beach surface during the damming process, as well as the variation rules of dam saturation line. Results suggested that, the tailings particles gradually became finer along the dry beach surface to inside the impoundment. The particle size suddenly changed at the junction between the deposited beach and the water surface, which displayed an obvious coarsening phenomenon. Besides, the deposited beach exhibited the vertical feature of coarse upward and fine downward on the whole. Additionally, in the physical model, the saturation line elevated with the increase in dam height, and its amplitude was relatively obvious within the range of 1.0-4.5 m away from the initial dam. Under flood condition, the saturation line height was higher than that under normal condition on the whole, with the maximum height difference of 4 cm. This study could provide an important theoretical basis for further studies on dam failure experiments and the evolution rules of leaked tailings flow.

• Journal of the Korean Institute of Gas
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• v.22 no.1
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• pp.1-8
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• 2018

FCV is installed with a automatic valve attached in an high pressure cylinder to control the hydrogen flow. The supply of hydrogen from the cylinder into the fuel cell stack is controlled via the on/off operation of a solenoid attached to the automatic valve. The solenoid needs to provide the necessary attraction force even at any saturation temperature caused by drive of the vehicle. In this study, the simplified prediction equations for the saturation temperature are suggested. The finite element analysis was performed by steady state technique, according to the boundary condition in order to predict the saturation temperature and attraction force. Finally, the saturation temperature was validated through comparison between the analysis results and measurement results. From the results, the measured saturation temperature $5.9^{\circ}C$ lower with respect to the analysis results. And the error of attraction force ranged from 1.0 to 2.1 N at testing conditions.

• Korea-Australia Rheology Journal
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• v.21 no.1
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• pp.71-79
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• 2009

The incomplete saturation and the void formation during the resin infiltration into fibrous porous media in the resin transfer molding process cause failure in the final product during its service. In order to better understand flow behavior during the filling process, a finite-element scheme for transient flow simulation across the micro-structured fibrous media is developed in the present work. A volume-of- fluid (VOF) method has been incorporated in the Eulerian frame to capture the evolution of flow front and the vertical periodic boundary condition has been combined to avoid unwanted wall effect. In the microscale simulation, we investigated the transient filling process in various fiber structures and discussed the mechanism leading to the flow fingering in the case of random fiber distribution. Effects of the filling pressure, the shear-thinning behavior of fluid and the volume fraction on the flow front have been investigated for both intra-tow and the inter-tow flows in dual-scale fiber tow models.

• Electrical & Electronic Materials
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• v.7 no.3
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• pp.206-212
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• 1994

In this paper, We discuss the $POCI_3$ doping process according to the variation of deposition temperature, gas flow rate and doping time. The factors acted with $POCI_3$ doping are gas flow rate deposition temperature and time etc. Among them the temperature is the most important factor. For the $POCI_3$ flow rate, it should not exceed the resistivity saturation point developed on poly surface by annealing treatment. Therefore, this study suggests the optimum conditions of Poly-silicon treatments with the $POCI_3$ flow rate.