• Journal of Chest Surgery
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• v.7 no.1
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• pp.93-100
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• 1974

This is a case report of successful surgical correction of coarctation of the aorta associated with the patent ductus arteriosus and the persistent left superior vena cava. The patient was a 15 year old girl and congenital heart anomaly was suspected at the sixth month after birth. Afterward there has been no embarrassing symptoms until the day of operation except slight dyspnea on exertion, The diagnosis of coarctation of the aorta and the patent ductus arteriesus detected by physical signs and X-ray studies including aortography. In the first place, coarctation of the aorta was corrected with following procedure: partial resections of the aortic wall just above and below the coarctating line of the aorta and removal of diaphragmatic structure of coarctation performed by. cross clamping aorta above and below coarctation, and then the defect of the aortic wall was closed by lateral aortorrhapic suture with atraumatic needle 3-0 silk continuously [Fig. 6]. In the second place, the patent ductus arteriosus was closed with double ligation method. The persistent left superior vena cava left as it has been, because there has been no evidence of hemodynamic abnormal shunt. After operation, excellent result was obtained; blood pressure in the upper and lower extremities was normalized and subjective complains of hypertension in the upper extremity was disappeared.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.57-64
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• 1994

The purpose of this paper is to find minimum surface shape of pneumatic structure using the finite element method. The pneumatic membrane structure is a kind of large deformation problem and very flexible composite material, which mean geomatric nonlinearity. It is not to resist for compression and resultant moment. As the displacement due to internal pressure is getting bigger, it should be considered the direction of forces. It becomes non-linear problem with the non-conservative force. The follower-force depends on the deformation and the direction of force is normal to each element. The solution process is obtained the new stiffness matrix (load correction matrix) depending on deformation through each iterated step. However, the stiffness matrix have not the symmetry and influence on the time of covergence. So in this paper Newton-Rhapson method for solving non-linear problem and for using symmetic matrix, the load direction is changed in each iterated step using the transformation matrix.

• Journal of computational fluids engineering
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• v.8 no.3
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• pp.1-6
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• 2003

Three-dimensional endwall flow within a linear cascade passage of high performance turbine blade is simulated with a 3-D Wavier-Stokes CFD code (MOSA3D), which is based on body-fitted coordinate system, pressure-correction and finite volume method. the endwall flow characteristics, including the development and generation of horseshoe vortex, passage vortex, etc. are clearly simulated, consistent with the generally known tendency The effects of both turbulence model and convective differencing scheme on the Prediction performance of endwall flow are systematically analyzed in the present paper. The convective scheme is found to have stronger effect than the turbulence modei on the prediction performance of endwall flow. The present simulation result also indicates that the suction leg of the horseshoe vortex continues on the suction side until it reaches the trailing edge.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.127-133
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• 2000

A numerical study of the flow of incompressible fluid in a polar cavity is presented. Irregular grids is proposed by applying the interior division principle to the variables on polar coordinate grid formation. Stability analysis and the pressure correction method of SOLA algorithms were discussed in detail on cylindrical coordinates. The results present that unsteady flow behavior appears over $Re=3{\times}10^4$ on polar cavities but nearly steady state at $Re=10^4$. Furthermore, with increasing Reynolds numbers, vortices behaviors indicate more complicated flow phenomena and more severe temporal fluctuation of total kinetic energy and time variation of velocity components at arbitrary pick-up points are detected in case of $Re=5{\times}10^4$.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.461-468
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• 2002

Prediction method of floor impact noise for light and heavy weight impact is described. Sound pressure level is predicted based on the impedance method. For floating floor system, noise reduction is studied assuming 1-D mass-spring system. It is found that comparisons of predictions and measurements show good agreements. However, certain correction factor is needed to predict noise reduction of floating floor system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.7
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• pp.907-915
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• 2000

The preconditioned Krylov subspace methods were applied to the incompressible Navier-Stoke's equations for convergence acceleration. Three of the Krylov subspace methods combined with the five of the preconditioners were tested to solve the lid-driven cavity flow problem. The MILU preconditioned CG method showed very fast and stable convergency. The combination of GMRES/MILU-CG solver for momentum and pressure correction equations was found less dependency on the number of the grid points among them. A guide line for stopping inner iterations for each equation is offered.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.241-249
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• 1985

Twenty-one patients with Double Chambered Right Ventricle [DCRV] associated with Ventricular Septal Defect [VSD] were treated by open heart surgery under cardiopulmonary bypass with moderate hypothermia in the Department of Thoracic and Cardiovascular Surgery, Hanyang University Hospital between June 1982 and October 1984. The following results were obtained 1. The symptoms and physical signs, specific for DCRV, could not be identified. 2. The radiologic findings on simple chest X-ray, specific for DCRV, could not be identified. 3. Electrocardiographic findings, specific for DCRV, could not be identified. 4. Cardiac catheterization was found to be the most important diagnostic method, revealing pressure gradient between proximal chamber and distal chamber in the right ventricle. The average pressure gradient between two chambers showed 48.1523.29 mmHg[varying from 15mmHg to 94mmHg]. 5. Cardiac angiography was found to visualize the anomalous muscle bundles in right ventricle [in 17 cases, 81%] but the evidence of pressure gradient between two chambers within right ventricle is considered necessary for the diagnosis of DCRV. 6. Via surgical observation, anatomical and pathologic findings of the anomalous muscle bundles, associated DCRV were identified. 7. As the direct pressure was measured on the operating table before and after surgery, the average pressure gradient across the muscle bundles showed 40.5219.75mmHg [varying from 16 to 89mmHg] preoperatively and 8.909.72mmHg [varying from 0 to 32mmHg] postoperatively, indicating significant surgical correction of the obstruction present. 8. The presence of anomalous muscle bundles, dividing the right ventricle into two separated chambers, and the presence of the pressure gradient over 15mmHg are considered necessary for the diagnosis of DCRV.

• Journal of KSNVE
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• v.11 no.1
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• pp.57-67
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• 2001

Proposed in this paper is a method of measurement of the flow rate in a pipe. The sound waves which are propagated within a pipe are characterized by that the wavenumber in the axial direction is changed according to the flow rate, and these characteristics are used in the present method of measurement of the flow rate. The amount of change in wavenumber of sound waves according to the flow rate can be obtained from the relationship among acoustic pressure signals within a pipe, which are measured by using a microphone array. The flow rate can be obtained by using the amount of change in wavenumber of sound waves and the relational equation of the flow rate. With respect to errors that can occur during the measurement of the flow rate, the types of errors and the method of correction of those errors are presented. This method of measurement of the flow rate has application limitation conditions due to the sensor interval, assumption of sound waves as plane waves, etc. The numerical simulation and experiments for measuring the flow rate of air in a pipe are performed in order to verify the applicability of this method of measurement of the flow rate. The experimental results are shown to be similar to those of the numerical simulation. And the flow rate measured is shown to be consistent with the actual value within 5% error bound.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.11 s.116
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• pp.1124-1131
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• 2006

This paper presents a novel method to determine sound power level(PWL) emitted by a travelling vehicle for road traffic noise simulation. The PWL is evaluated by the equivalent sound pressure level (SPL) measured by close proximity method and the sound power correction factor derived from the maximum SPL measured by pass-by method and the propagation attenuation of vehicle noise during the pass-by measurement. Using the method, we derive the empirical formula for PWL estimation in 1/1-octave and overall frequency bands for 8 vehicles (automobile, SUV, small truck, large bus, trailer, 3 dump trucks) tested at two road surfaces (dense graded asphalt, 30mm transverse tinning concrete) of Korean highway test road. The suggested approach, if securing sufficient data to represent the acoustic characteristics of all vehicle types, has il strong merit to be able to evaluate sound power levels for any combination of vehicle categories and traffic volumes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.421-427
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• 2006

This paper presents a novel method to determine sound power level(PWL) emitted by a travelling vehicle for road traffic noise simulation. The PWL is evaluated by the equivalent sound pressure level(SPL) measured by close proximity method and the sound power correction factor derived from the maximum SPL measured by pass-by method and the propagation attenuation of vehicle noise during the pass-by measurement. Using the method, we derive the empirical formula for PWL estimation in 1/1-octave and overall frequency bands for 8 vehicles(automobile, SUV, small truck, large bus, trailer, 3 dump trucks) tested at two road surfaces(dense graded asphalt, 30mm transverse tinning concrete) of Korean highway test road. The suggested approach, if securing sufficient data to represent the acoustic characteristics of au vehicle types, has a strong merit to be able to evaluate sound power levels for any combination of vehicle categories and traffic volumes.