• Proceedings of the KSME Conference
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• 2000.04b
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• pp.561-567
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• 2000

This paper is concerned with the viscous interaction between rotor and stator. The viscous interaction is caused by wakes from upstream blades. The rotor cascade in the experiment was composed with five blades, and cylinders were placed to make the stator wakes and their locations were about 50 percent upstream of blade chord. The locations of cylinders were varied in the direction of cascade axis with 0, 12.5, 25, 50, and 75 percent of pitch length. The static pressure distributions on the blade surfaces and the velocity distributions in the cascade flow were measured. From the experimental result it was found that the value of velocity defect by a cylinder wake might vary depending on the wake position within the cascade but the value at the cascade exit approached to some constant value regardless of the difference of wake locus. The momentum defect at the downstream from the cascade and the pressure distribution on the blade surfaces showed that the wake flowing near the blade surfaces caused the decrease of lift and the increase of drag regardless of the disappearance of flow separation.

• Journal of Korea Foundry Society
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• v.28 no.5
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• pp.231-236
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• 2008

H-NCM(Hong-Nanocast Method)has several benefits such as a lower porosity defect and high quality casting comparing to conventional die casting. Influence of casting parameters of hybrid-lower arm in rheocasting process on the slurry flow and the amount of porosity defect was investigated using experimental and simulation methods. In the present study, the Carreau model was adopted to simulate the pattern of rheological flow. Optimal casting paremeters such as injection speed and stroke variations were established. Sound products with integral microstructure and sound shape of joinning different materials of Al and steel pipe without deforming the steel pipe were obtained by the H-NCM slurry and X-ray analysis also showed integral condition throughout the entire parts.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.45-53
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• 2009

Die casting process of Mg alloys for high temperature applications was studied to produce an engine oil pan. The aim of this paper is to evaluate die casting processes of the Aluminium oil pan and in parallel to apply new Mg alloy for die casting the oil pan. Temperature distributions of the die and flow pattern of the alloys in cavity were simulated to diecast a new Mg alloy by the flow simulation software. Dies have to be modified according to material characteristics because melting temperature and heat capacity are different. We changed the shape and position of runner, gate, vent hole and overflow by the simulation results. After several trial and error, oil pans of AE44 and MRI153M Mg alloys are produced successfully without defect. Sleeve filling ratio, cavity filling time and shot speed of die casting machine are important parameter to minimize the defect for die casting Magnesium alloy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1812-1816
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• 2011

This research developed chemical flow control system(CFCS) essential for spinner equipment in nano semiconductor manufacturing process under the 100nm to prevent complex process defect due to missing spread after chemical injection. The devices developed in this research, which can be swiftly replaced in case abnormal state element changes or wafer manufacturing defect occurs, are anticipated to improve module yield as well as real-time monitoring on the state element. In addition, as a result of mounting H/W and S/W system to control detailed operation sequence in production line and executing performance check and verification, we can be exactly detected in five abnomal process type.

• Journal of Chest Surgery
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• v.24 no.11
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• pp.1149-1153
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• 1991

A modified procedure for the operative management of the corrected transposition of the great arteries with ventricular septal defect and pulmonary stenosis or atresia was performed in 4 patients. (age ; 18 months-9 years). The operation consists of a venous switch procedure (Senning), intraventricular baffling directing the blood flow from the morphologic left ventricle into the aorta via ventricular septal defect through the right ventriculotomy, and insertion of valved conduit between the morphologic right ventricle and the pulmonary artery. All the four patients had large non-restrictive ventriular septal defects and no evidence of significant mitral valve regurgitation. Both ventricles were well-developed. Three cases had pulmonary atresia, and the remainder had severe subpulmonic stenosis. Postperatively, all patients showed no findings of systemic or pulmonary venous obstruction withnormal sinus rhythm. One patient died of sepsis due to infection by Methicillin-resistant S. aureus on the thirteenth postoperative day. Follow-up is done on the survivors, and all of them are dong well with regular sinus rhythm, with their functional class I or II at 2 to 8 months after the operation.

• Journal of Chest Surgery
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• v.22 no.4
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• pp.655-660
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• 1989

The unroofed coronary sinus syndrome is a spectrum of cardiac anomalies in which part or all the common wall between the coronary sinus and the left atrium is absent. This defect is part of a developmental complex which includes absence of the coronary sinus and termination of a persistent left superior vena cava in the left atrium. Recognition of this complex is important so that interruption or diversion of the left superior vena cava may be done to prevent subsequent central nervous system complications. Surgical correction uses an intraatrial baffle to divert flow from the left superior vena cava to right atrium and to close the atrial septal defect. This report describes a 7 years old female patient in whom the left superior vena cava was identified preoperatively and the complex [unroofed coronary sinus syndrome, common atrium, mitral valve cleft] recognized at the time of operation. Surgical correction, following repair of cleft mitral valve, utilized a Dacron patch baffle to route the left caval blood to the right atrium and included closure of the atrial septal defect

• Journal of Chest Surgery
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• v.18 no.3
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• pp.440-445
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• 1985

Cor triatriatum is a variant of abnormal connection between the pulmonary vein and true left atrium, which is separated from accessory left atrium receiving pulmonary venous blood flow by fibromuscular diaphragm. Usually it is diagnosed after operation because difficulty in visualization of the diaphragm by conventional diagnostic tools. We experienced a rare entity of congenital heart disease diagnosed as car triatriatum with atrial septal defect and partial anomalous pulmonary venous return after completing operation, which was diagnosed as ASD with PAPVR preoperatively. Anomalous right pulmonary venous opening was located at right atrium, secundum type defect of atrial septum was present, and dual chambered left atrium without connection was also seen. Excision of the diaphragm and wide patch repair of ASD including right pulmonary vein were performed with good postoperative results. Herewith, we report this case with review of literatures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.54-58
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• 1994

H$_2$ bake and GeH$_4$ clean are used as a in-situ pre-clean method in low temperature Si based epitaxial growth technology using rapid thermal processing chemical vapor deposition (RTPCVD). In this paper, the H$_2$ bake and GeH$_4$ clean processes are optimized for low surface defect density using Taguchi method. In H$_2$ bake process, the epitaxial growth temperature affects dominantly on the surface defect density, and the next affecting factors are H$_2$ bake temperature and rinse time in de-ionised water. In GeH$_4$ clean process, GeH$_4$ clean temperature affects most strongly on the surface defect density, and the minor factor is GeH$_4$flow rate. The optimum process conditions predicted fly Taguchi method agree well with tile experimental data in both in-situ clean processes.

• Journal of Chest Surgery
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• v.26 no.7
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• pp.543-547
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• 1993

Cor triatriatum is a rare entity of congenital heart disease characterized by the presence of a fibrousmuscular diaphragm that subdivides the left atrium into a proximal or "accessory" chamber and a distal or "true" left atrial chamber. In the other hand, cor triatriatum is a variant of abnormal connection between the pulmonary vein and true left atrium which is separated from accessory left atrium receiving pulmonary venous blood flow by fibromuscular diaphragm. We experienced two cases of cor triatriatum. One of them was classical, and the other case was combined with atrial septal defect and all pulmonary veins were drained into the " common pulmonary venous chamber " which connected with right atrium and there was no direct communication between the accessory chamber and true left atrium. The abnormal diaphragms were excised and the atrial septal defect was repaired with pericardial patch in case II. The postoperative courses were not eventful and the patients were discharged with good result, and have been in good condition upto now.n good condition upto now.

• Journal of Institute of Convergence Technology
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• v.3 no.2
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• pp.17-21
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• 2013

Hot cross wedge rolling process as an incremental forming has many advantages such as the material usage, the short process time, the automatic equipment line and the low forming load. However, it occurs some defects such as the surface groove, the axis warping and the Mannesmann hole. In this paper, the defect of the Mannesmann hole was carried out. Finite element analysis was utilized to reveal the stress distribution, the rotation of the specimen and the change of section profile. Cross wedge rolling experiment was also conducted on the generation of the Mannesmann hole. It was demonstrated according to the spreading angle with respect to the various types of material. In the view point of metal flow, the smaller forming angle and the larger spreading angle increase opportunities of the defect hole generations.