• 한국전산유체공학회:학술대회논문집
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• 2000.05a
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• pp.99-106
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• 2000

A method of two and three dimensional orthogonal grid generation with control of spacing by using the covariant Laplace equation is Presented. An important feature of the methodology is its ability to control effectively the grid spacing especially near the boundaries still maintaining good orthogonality in whole field. The method is based on the concept of decomposition of the global transformation into consecutive transformation of an approximate conformal mapping and au auxiliary orthogonal mapping to have linear and uncoupled equations. Control of cell spacing is based on the concept of reference arc length, and orthogonal correction is performed in the auxiliary domain. It is concluded that the methodology can successfully generate well controlled orthogonal grids around bodies of 2 and 3 dimensional configurations.

• Journal of computational fluids engineering
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• v.16 no.1
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• pp.73-82
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• 2011

In this paper, the vortex-induced vibration of circular cylinders is studied using the immersed boundary method on the Cartesian mesh. The Reynolds numbers considered is from 100 to 200. Using the configuration of tendemly arranged multiple circular cylinders, the vortex shedding behind of the cylinders and their flow-induced motion are investigated. The staggered MAC grid arrangement, which is the typical grid system for the incompressible flow on the Cartesian meshes, is utilized. Pressure correction method is applied for solving the divergence-free incompressible velocity field. The body motion is described by immersed boundary technique that has advantages for moving object on the fixed computational domain. It is also discussed for the computational noise in hydrodynamic forces when body motion is represented by the immersed boundary method. The Predictor/Corrector method is used for simulating the nonlinear response of the elastically mounted cylinder excited by vortex-shedding.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.588-592
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• 1992

The electrons, which are accelerated to nearly light speed from LINAC(Linear Accelerator), put into Storage Ring. And this electrons circulate in an ultra high vacuum chamber and their orbit is controlled by the electromagnets such as DIPOLE, QUADRUPOLE, SEXTUPOLE & CORRECTION MAGNET. Among them, the dipole magnet is to bend the electron and to produce Synchrotron Radiation(S.R). This paper describes the key point during manufacturing of this magnet, and introduce the field measurement results of the HEECO's successful prototype.

• Journal of Chest Surgery
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• v.13 no.2
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• pp.154-157
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• 1980

A twenty three year old, Primigravida and 32 week pregnant woman who has been complained dyspnea, chest pain, nausea and vomiting was admitted to this chest surgical department on Feb. 19, 1979. Physical findings were those of acutely ill appearance, decreased thoracic excursion and absence of breath sounds in the left hemithorax. Roentgen examination of the chest revealed reticular cystic densities in the left, particularly in lower lung field with collapse of the left lung. Correction of the diaphragmatic hernia was carried out with reduction and repair of the hernia through transperitoneal approach. On exploration, the defect of the diaphragm was 12 x 12 cm in size and was located posterolateral area of left diaphragm. Hernia contents were stomach, spleen, omentum and splenic flexure of large bowel. The baby was normal full term spontaneous delivered at 36th POD. Diaphragmatic hernia complicated by pregnancy is a rarity and mortality is extremely high. Therefore, the literatures have reviewed and the case is reported.

• Journal of Chest Surgery
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• v.20 no.4
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• pp.773-779
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• 1987

MOVC is an uncommon disease which can be corrected by surgical method if early detected. A case of a 34-year-old male with MOVC is reported. Operation was done on cardiopulmonary bypass with circulatory arrest under moderate hypothermia. The incision was done both on the RA extending to level of suprahepatic IVC and on the IVC just proximal to the right renal vein. And then, thrombectomy and membranectomy under the direct visualization was done. Total circulatory arrest was used intermittently in order to get good visual field and for preventing blood loss. The Postop. course was good except one episode of hepatic encephalopathy which was persisted for 12 hours and then controlled by conservative measures.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.209-213
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• 2003

It is advantage of accelerated vibration testing to compress service exposures to operating vibration into a reduced laboratory test by increasing the amplitude or frequency of the applied input excitations. This paper proposes an accelerated test method to estimate the high-cycle fatigue life under random excitation. The method consists of conducting a test with amplified input excitation and extrapolating linearly the lift in the accelerated condition into the real lift in field condition. The extrapolation is carried out applying the high-cycle irregular excitation fatigue theory including the rainflow counting, Miner’s damage accumulation rule, and Goodman’s mean stress correction. As a verification, those estimated lift is compared with that acquired by experiment f3r the simple case of spot welding specimen with good agreement. This testing procedure will provide an useful scheme that can reduce testing period associated with developing time schedule of new product.

• Journal of the Korean Society of Combustion
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• v.6 no.2
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• pp.15-22
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• 2001

A pressure-based, unstructured finite volume method has been applied to couple the chemical kinetics and fluid dynamics and to capture effectively and accurately the steep gradient flame field. The pressure-velocity coupling is handled by two methodologies including the pressure-correction algorithm and the projection scheme. A stiff, operator-split projection scheme for the detailed nonequilibrium chemistry has been employed to treat the stiff reaction source terms. The conservative form of the governing equations are integrated over a cell-centered control volume with collocated storage for all transport variables. Computations using detailed chemistry and variable transport properties were performed for two laminar reacting flows: a counterflow hydrogen-air diffusion flame and a lifted methane-air triple flame. Numerical results favorably agree with measurements in terms of the detailed flame structure.

• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.369-383
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• 2018

In this work, a novel hyperbolic shear deformation theory is developed for free vibration analysis of the simply supported functionally graded plates in thermal environment and the FGM having temperature dependent material properties. This theory has only four unknowns, which is even less than the other shear deformation theories. The theory presented is variationally consistent, without the shear correction factor. The present one has a new displacement field which introduces undetermined integral variables. Equations of motion are obtained by utilizing the Hamilton's principles and solved via Navier's procedure. The convergence and the validation of the proposed theoretical model are performed to demonstrate the efficacy of the model.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.3
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• pp.162-168
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• 1992

Numerical solutions to the advection equations used for long-range transport air pollution models are calculated using three numerical methods; Antidiffusion correction method(Smolarkiewicz, 1983), Positive definite advecton scheme obtained by nonlinear renormalization of the advective fluxes(Bott, 1989), and Positive definite pseudospectral method(Bartnicki, 1989). Accuracy, numerical diffusion and computational time requirement are compared for two-dimensional transport calculations in a uniform rotational flow field. The solutions from three methods are positive definite. Bartnicki(1989)'s method is most conservative but requires approximately 10 times as much computational time as Smolarkiewicz(1983)'s method of which numerical diffusion is the largest. All three methods are more conservative for a cone shape initial condition than for a rectangular block initial condition with a steep gradient.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.19-23
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• 1990

A new technique for reducing the susceptibility artifact in gradient echo imaging which uses a tailored RF pulse is proposed. It is applied to the case of imaging where artifacts and distortions arise due to the high local magnetic field inhomogeneity i. e., the susceptibility. The signal loss and void phenomena due to susceptibility in a voxel are studied and a correction method using a tailored RF pulse is proposed. Applications of this method in imaging are given and experimental results obtained using an human volunteer with a 2.0 T KAIS NMR system are presented.