• Journal of computational fluids engineering
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• v.6 no.2
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• pp.32-39
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• 2001

Hypersonic analysis on the KSR-Ⅲ payload configuration has been performed using an axisymmetric Navier-Stokes code. A numerical code based on the Harten and Yee's upwind TVD scheme with simplified curve fits in the chemically reacting equilibrium air was developed. The carbuncle phenomenon on detached shock in front of the payload is controlled by using pressure gradients to tune the dissipation. Chemically reacting equilibrium computations for the reentry flight conditions of Mach No. 10.2, 8, 4.9 are presented and compared with the results of calorically perfect gas.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.6
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• pp.600-606
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• 2009

In this paper, the coupled model with hydrogen transport and elasto-plasticity behavior is introduced. This model is implemented to the general-purpose FE code, ABAQUS, via the user-defined subroutine UMAT and UMATHT. In UMAT, the spatial gradients of hydrostatic stress and hydrogen induced deformation are calculated, and then are passed into UMATHT. Heat transfer equation within UMATHT is substituted by hydrogen transport equation including the effects of stress states and strain hardening. To validate this model, the finite element analyses coupled with hydrogen transport and mechanical loading are performed for the boundary layer specimens with low and high strength steel properties. The FE results are compared with the previous studies by Taha and Sofronis (2001).

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.2
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• pp.219-228
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• 2003

The purpose of this study were to examine the characteristics of arm types proposed in the previous study and to present sleeve patterns according size and shape of 4 arm types. 31 direct and indirect items were measured. The subjects for this study were 132 females of twenties. The results were as follows. 1. All of the direct measurements showed significant difference by the arm types. especially at the front armhole part. Such a.: the items of arm gradients, armhole sizes belong to the indirect measurements made clear difference also. 2. By the discriminant analysis, 9 items including underarm length, front armhole girth, upper arm girth, degree of elbow point-wrist point discriminated arm type by the hit ratio of 90.4% Item related to shape of arm rather than size made a sharp distinction. 3. Through the examination of existing patterns and wearing tests on the subjects among 4 groups, sleeve patterns classified by the arm type were suggested.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.62-74
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• 2001

In this study, the prediction of performances and emissions of the gasoline engine of a light passenger car has been accomplished. The method of characteristics including friction, heat transfer, area change and entropy gradients was used to analyze the flow in the intake and exhaust systems. For in-cylinder calculation, the single-zone model was adopted for the periods of the intake, exhaust, compression and the expansion of the burnt gas and the 2-zone expansion model was applied to the period of combustion process. The simulation program was verified by comparison with the experimental values both for the naturally aspirated engine and the turbocharged engine showing good agreements. Using the simulation program, multi-valve system and turbocharging were examined as a means of increasing engine Performances.

• 한국해양학회지
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• v.20 no.2
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• pp.22-27
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• 1985

To examine the summertime coastal current along the cast coast of Korea, we carried out hydrographic and current measurements in the coastal area of Chumunjin during July-August, 1982. Hydrographic results showed that isotherms, isohalines and isopycnals had a downward slope toward the coast in a layer of 0∼100m and that there existed relatively large horizontal gradients across shelf of salinity and density, mainly due to heavy precipitation in summer. It was found that there existed a strong southward flow along the coast reaching its maximal speed of about 70cm/sec in the nearshore area and that shear and speed of the observed current were coincident with orders of geostrophic current.

• Tunnel and Underground Space
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• v.7 no.4
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• pp.334-340
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• 1997

Alpha center theory which was first proposed by Stefanescu has been proved to be effective for the detection of the location of the conductive orebody. A numerical forward modeling was conducted to verify the effectiveness of this method. Field works were carried out along the three profiles in two different areas for the purpose of finding fractured zone which might be accompanied with the presence of the groundwater. And the results were modeled by alpha center method, which was later testified by wellproven 2-dimensional finite difference inversion scheme. Field data could be successfully modeled with this alpha center algorithm, especially for the smooth-varying resistivity models. For the abrupt change of the resistivity values, the alpha center coefficients have a tendency to be negative to simulate the steep resistivity gradients. This method is quite simple and easy for the future applications. The numerical calculation can be performed very quickly with the personal computers.

• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.245-250
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• 1992

This study was performed to demonstrate the presence of large granular lymphocyte(LGL) in Sprague-Dawley(SD) rats and morphologically observe NK cell and also establish the method of isolation of natural killer cell in SD rats. By percoll discontinuous density gradients centrifugation, highly enriched LGL population were shown to fraction 2(border line between 44.2% and 50.8%). LGL were shown to bind selectively to YAC1 mouse lymphoma cell. This fraction expressed very high NK cell cytolysis. Therefore, we thought that LGL have NK activity in SD rats. The Morphology of rat LGL is very similar to that of human LGL. These cells have an eccentric kidney-shaped nucleus. Their most distinctive feature was their cytoplasmic azurophilic granules. Another distinguishing feature of rat LGL was their high cytoplasmic : nuclear ratio. It was concluded that LGL played a role part in mediating natural killer activity in this species.

• Macromolecular Research
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• v.11 no.6
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• pp.467-470
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• 2003

The dielectrophoretic technique was used to prepare density gradient polymers, polystyrene doped with a dipolar modifier, diphenyl sulfide. We have measured concentration gradients of the dopant by UV/Nis spectroscopy as a function of time in a nonuniform electric field. Measured concentration data at different positions of the sample confirmed that a concentration gradient arose after a nonuniform electric field was applied to the system, these data were used to compare the concentration profile with that predicted by the dielectrophoresis equation.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1002-1007
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• 2010

This study evaluates the electro-osmotic hydraulic conductivity for the clay specimen by applying the series of the voltage gradient simultaneously with different stress conditions. The test results shows that the shrinkage of voids corresponds to the linear decrease in the electro-osmotic seepage velocity, and the changes of electro-chemical characteristics in the specimen induces the gradual decrease of the electro-osmotic seepage velocity with the constant voltage gradient.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.218-222
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• 1987

Unroofed coronary sinus syndrome is an uncommon anomaly, Unroofed coronary sinus syndrome is caused by incomplete formation of the left atriovenous fold, and it usually is associated with Left SVC. If it is not diagnosed, a residual reversed or bidirectional shunt will result, and its complications will reduce life expectancy. We experienced 3 cases of unroofed coronary sinus syndrome which combines TOF with PLSVC, partial ECD, primum type ASD. In case of Unroofed coronary sinus syndrome which combines TIF with PLSVC, preoperative diagnosis was not made. In corrective operation for TOF of this case, pump weaning was failed due to hypoxia and cardiac arrest, and he expired at operation room. At autopsy of this case, complete unroofed coronary sinus was found. In the other 2 cases, partial unroofed coronary sinus syndrome was found in operation field and corrective operation was performed successfully. We report these 3 experiences with its review. ^u ++ Noninvasive Assessment of Pressure Gradients across Prosthetic Heart Valve by Doppler Ultrasound - A comparative study of the Duromedics Bileaflet Valves in mitral position and Normal Mitral Valves -with its review.