• Journal of Chest Surgery
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• v.16 no.3
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• pp.310-315
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• 1983

The combined anomaly of pulmonary stenosis with atrial or ventricular septal defects is usually associated with decreased pulmonary blood flow and right to left shunt, and result in generalized cyanosis. Non-cyanotic pulmonary stenosis patients have generally been considered to have isolated pulmonary stenosis with intact septa. We are going to report a case of pulmonary stenosis with septal defects who have no frank cyanosis at rest because of the predominant intracardiac shunt from left to right. Recently, we managed surgically a case of pulmonary valvular stenosis combined with secundum type atrial septal defect, type II ventricular septal defect, and patent ductus arteriosus. The clinical manifestations of this patient were exertional dyspnea, frequent upper respiratory infection, chest discomfortness and lethargy since late childhood and these had been progressively aggravated. Pulmonary valvular stenosis, atrial septal defect and ventricular septal defect were closed through simply right atriotomy and patent ductus arteriosus through pulmonary arteriotomy. Immediate postoperative course was uneventful and one year follow up is excellent.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.345-348
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• 2006

In sheet metal forming process using press and draw die some defect can be made because of the high pressure of air pocket between draw die and the product. The purpose of this study is to develop a program to decide an optimal combination of air vent hole size and number to prevent those defect on product. The air inside air pocket is considered as ideal gas and the compression and expansion is assumed as isentropic process. The mass flow is computed in two flow condition: unchocked and chocked condition. The present computation obtains required cross-sectional area of air vent hole for not exceeding the user specified pressure such as the pressure for yielding strength of the product or the pressure for unchocked flow. To validate the program the present results are compared with the results of other researchers and commercial CFD code.

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.224-232
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• 2005

The high-pressure die-casting is one of the most effective methods to produce a large amount of products in short cycle time. This process, however, has a problem that the gas porosity defect appears easily. The generation of gas porosity is known mainly due to the air entrapment during the injection stage. Most of numerical simulations for the molten metal flow pattern observations have done in the treating of one phase fluid flow but the gas-liquid interface is essentially multi- phase phenomenon. In this paper, the two-phase fluid flow numerical simulation methods have been adapted to predict the gas porosity generations in the molten metal. The accuracy and the usefulness of the new simulation module have been emphasized and verified through some comparison experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.596-602
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• 2018

Nanoimprint lithography (NIL) is an emerging technology that enables cost-effective and high-throughput nanofabrication. In ultraviolet (UV) NIL, low-cost and high-speed production can be achieved using a non-vacuum environment at room temperature and low pressure. However, there are problems with the formation of bubble defects in such an environment. This paper investigates the shape of the mold cavity and the bubble defect formation in UV NIL in a non-vacuum environment. The bubble defect formation was simulated using two-dimensional flow analysis and the VOF method for commonly used cavity mold shapes (rectangular, elliptical, and triangular). The characteristics of the resist flow front and various contact angles were also analyzed. The shape of the mold cavity had a very significant effect on the bubble defect formation. For all cavity shapes, a smaller contact angle with the mold and larger contact angle with the substrate decreased the possibility of bubble defect formation. The elliptical shape was the most effective for preventing bubble defect formation.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.303-303
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• 2010

비정질 실리콘 박막 태양전지의 수광부인 i-layer는 비정질의 특성 상 많은 defect을 함유하고 있다. 이러한 defect들은 빛에 의하여 생성된 전자정공 재결합에 있어서 주도적으로 작용하게 된다. $H_2$는 이러한 defect들의 생성을 줄여주어 박막의 특성을 향상시켜주는 것으로 알려져 있다. 본 논문에서는 비정질 박막 태양전지의 수광부로 사용되어지는 i-layer의 $H_2$ gas flow rate의 변화에 따른 태양전지의 특성을 simulation해 보았다. $H_2$는 1:0에 1:5까지 변화시켰고 그에 따른 태양전지의 QE, LIV, DIV 곡선을 통하여 특성을 알아보았다. 또한 추가적으로 i-layer의 두께에 따른 효율의 변화도 simulation해 보았다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.289-292
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• 2006

In this paper, the hybrid algorithm of Support Vector Machine md Artificial Neural Network is used for the defect diagnostics algorithm for the aircraft turbo-shaft engine. The results of learning of ANN, especially, accuracy or speed of convergence are sensitive to the number of data, so a comparison between design point and off-design area, especially, Mach number and fuel flow variable area, is essential research. From application results for diagnostics of gas turbine engine, it was confirmed that the hybrid algorithm could detect well in the of-design area as well as design point.

• Journal of Veterinary Clinics
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• v.34 no.2
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• pp.90-93
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• 2017

A nine-month-old intact female Maltese dog (body weight: 1.5 kg) presented with frequent syncopal episodes (1-2/day), exercise intolerance, and dyspnea. Cardiomegaly with marked dilation of right and left atria along with ascites was indicated on radiography. Tricuspid regurgitant jets (4.36 m/s), pulmonary regurgitant jets (3.4 m/s), left-to-right shunting flow at the ductus arteriosus, and an atrial septal defect were observed on echocardiography. A bubble study with agitated saline found right-to-left shunting at the interatrial septum. Based on diagnostic studies, the dog was diagnosed with right-to-left atrial septum defect (ASD) compounded with patent ductus arteriosus (PDA). The treatment was directed to reduce the pulmonary hypertension, improve cardiac performance, and lower fluid retention. Despite medical treatment for 2 months, the dog died of sudden cardiac arrest. Herein, we describe a very rare case of right-to-left ASD compounded with PDA.

• Geomechanics and Engineering
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• v.22 no.5
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• pp.461-473
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• 2020

Natural rock mass contains defects of different shapes, usually filled with inclusions such as clay or gravel. The presence of inclusions affects the failure characteristics and mechanical properties of rock mass. In this study, the strength and failure characteristics of rock with inclusions were studied using the particle flow code under uniaxial compression. The results show that the presence of inclusions not only improves the mechanical properties of rock with defects but also increases the bearing capacity of rock. Circular inclusion has the most obvious effect on improving model strength. The inclusions affect the stress distribution, development of initial crack, change in crack propagation characteristics, and failure mode of rock. In defect models, concentration area of the maximum tensile stress is generated at the top and bottom of defect, and the maximum compressive stress is distributed on the left and right sides of defect. In filled models, the tensile stress and compressive stress are uniformly distributed. Failing mode of defect models is mainly tensile failure, while that of filled models is mainly shear failure.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.317-321
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• 2008

Piping in the Nuclear Power plants (NPP) are mostly consisted of carbon steel pipe. The wall thinning defect is mainly occurred by the affect of the flow accelerated corrosion (FAC) of fluid which flows in carbon steel pipes. This type of defect becomes the cause of damage or destruction of piping. Therefore, it is very important to measure defect which is existed not only on the welding partbut also on the whole field of pipe. Over the years, Infrared thermography (IRT) has been used as a non destructive testing methods of the various kinds of materials. This technique has many merits and applied to the industrial field but has limitation to the materials. Therefore, this method was combined with lock-in technique. So IRT detection resolution has been progressively improved using lock-in technique. In this paper, the quantitative analysis results of the location and the size of wall thinning defect that is artificially processed inside the carbon steel pipe by using IRT are obtained.

• Journal of Chest Surgery
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• v.20 no.2
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• pp.411-415
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• 1987

We have experienced a rare case of traumatic ventricular septal defect caused by fall down injury. The patient suffered from congestive heart failure after trauma and represented new developing typical murmur. Cardiac catheterization revealed a large left-to-right shunt at the ventricular level and a 4.4:1 ratio of pulmonary to systemic flow. Left ventricular angiogram also showed ventricular septal defect low in the muscular septum. At operation, the right ventricle and pulmonary artery were found to be moderately dilated. A marked systolic thrill was palpable over the right ventricle near the apex. Through a small left ventriculotomy an oval defect, 2x.3 cm with a firm scarred margin, was found in the lower muscular ventricular septum. This defect was repaired using Dacron patch and ventriculotomy was closed with long strip of Teflon felt. Postoperative course was uneventful and discharged in good condition.