• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.4
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• pp.243-254
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• 2020

Korean traditional kite has the unusual shape of the elongated rectangle with the center hole. The aerodynamic forces are numerically computed on Korean traditional kite with aspect ratio 1:1.5 by using FLUENT software. Simulating the flight of the kite with various diameters of the center hole, the present study has investigated the role of the center hole as well as the effect of diameter of the center hole. The center hole plays a role in relieving the sudden increase of tension associated with fast rewinding of the kite thread in kite fighting, thereby enabling faster rewinding of the kite thread. The proper diameter of the center hole is 1/3 of the width.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.7
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• pp.561-566
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• 2014

Our Korean traditional cultural inheritance Bangpae Kite has the stable rectangular shield shape decorated with artistic paint or poem and a good flight performance due to the central wind hole. In this paper, to analyse the wind hole effect to kite performance we performed the wind tunnel testing of the various design factor of kite model and air flow visualization passing through the wind hole. As the result of aerodynamic analysis, we knew that the wind hole of kite displays similar function of slot system for the wing high lift device. This fact demonstrates that our ancestor understood the function of slot system and applied effectively to the development of kite flight performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.9
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• pp.866-870
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• 2011

In this paper, the aerodynamic forces of a Korean Traditional Bangpae Kite with the wind hole and spanwise curved dihedral were measured by wind tunnel test. For the flat plate kite without the wind hole, the stall presents at ${\alpha}=35^{\circ}$ with $C_{Lmax}$=1.2. The Korean Traditional Bangpae Kite with the wind hole had $C_{Lmax}$=1.05 at ${\alpha}=30^{\circ}$ without the apparent stall phenomena. As the wind hole size growing, the lift and drag of kite were changed slowly after stalling angle of attack. As increasing the leading edge dihedral angle, lift curves were more increased than drag curves. As the growing of wind hole size, the effect of dihedral angle was constant affect to the lift and drag of kite.

• Korean journal of food and cookery science
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• v.29 no.4
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• pp.361-366
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• 2013

This research was performed to investigate the effect of Agarum cribrosum ethanol extracts on the levels of lipids in the serum of rats fed a high-fat diet for 10 weeks. Experimental groups were divided into basal diet only (BDG), high fat diet control (HFDCG), high-fat diet and 5% Agarum cribrosum ethanol extract powder (HF5S), and high-fat diet and 10% Agarum cribrosum ethanol extract powder(HF10S) groups. The levels of hematological variables were not significantly different among the four groups. Compared with the control group's serum total cholesterol level of 89.14 mg/dL, the levels of the HF5S and HF10S groups were significantly lowered to 77.26 and 75.47 mg/dL, respectively. Compared with the control group's LDL-cholesterol leve of 27.41 mg/dL, the LDL-cholesterol levels of the HF5S and HF10S groups were significantly lowered to 20.64 and 20.17 mg/dL, respectively. Also, compared to the control group's serum triglyceride level of 98.36 mg/dL, the triglyceride levels of the HF5S and HF10S groups were significantly lowered to 87.94 and 87.39 mg/dL, respectively. These results indicate that dietary intake of Agarum cribrosum ethanol extracts might have beneficial effects on obesity by reducing body weight and improving blood lipid profile.

• Journal of Chest Surgery
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• v.36 no.9
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• pp.683-686
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• 2003

Isolated right ventricular hypoplasia is a rare clinical entity. We describe a case of right ventricular hypoplasia, single atrium and spongy myocardium of left ventricle. The volume of right ventricle was half the volume of left ventricle and z-value of tricuspid valve was -4 preoperatively The patient, 6-year-old boy, underwent atrial partitioning with 3 mm fenestration, Postoperative course was smooth and he tolerated the biventricular state well during follow-up. Follow-up catherterization was done 27 months later The tricuspid valve grew well (z-value= -0.4) and atrial septal fenestration is closed spontaneously. This article reports a case of successful biventricular repair in a patient with isolated right ventricular hypoplasia.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.923-928
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• 1997

An MCP (Microchannel Plate) is a secondary electron multiplier to detect and amplify electrons. An MCP has many rnicrochannels whose diameters range from 10 to 100pm and whose lengths range from 40 to 100times of the diameter. Each microchannel of the MCP amplifies electrons over IOOOtimes by the secondary electron emission. Even though MCPs have high performance for electron amplification, the application of MCPs is limited to high performance electronic equipments because of their high fabricating cost and the limit of increasing their size due to the conventional fabrication process. Therefore, in this work, microchannels of the MCP are manufactured by micro-drilling to reduce the cost of the MCP and to increase their size. Alumina green body with epoxy binder was machined for fabricating microchannels using a high speed air turbine spindle and micro-drills with diamond grinding abrasives. Then alumina MCP was fabricated through the sintering of the machined alumina green body.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.175-178
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• 2017

본 논문에서는 공을 쳐서 구멍에 넣는 당구 게임을 제작하면서 실제 물리 현상과 같은 충돌 구현을 위해 사용한 여러 가지 상황에서의 원형 물체의 2차원 탄성 충돌 모델 구현 방법에 대하여 연구하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.2
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• pp.145-151
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• 1994

앞 턱 부위가 짧고 후방으로 위치해 있을 때 턱의 높이를 증가시키고 전방으로 돌출시키는 축조 이부성형술의 방법으로는, 매식체 삽입술, 골 절단술, 골 절제술 또는 이들을 동시에 시행하는 혼합술등이 행해져 왔다. 그러나 매식체 삽입술에서는 감염 또는 매식체의 유동성 등의 합병증의 발병이 빈발하고 매식체의 밑 부위에 골이 흡수된다든지 연조직의 변화를 예측하기 어렵다든지 하는 복잡한 문제점들이 종종 보고되고 있다. 따라서 매식체를 이용하지 않는 골 절단술이나 골 절제술만을 이용한 다양한 방법의 이부성형술이 많이 시행되고 있다. 하악골이 전후방 관계로 발육부전인 환자에게 양측 하악지 시상분할술을 시행하여 전방 이동시킨 후 앞 턱의 위치를 좀더 개선하기 위하여 $Michel{\'{e}}t$ 테크닉의 변형법을 이용한 이부성형술을 추가로 시행하였다. 이 방법의 이부성형술은 턱의 수직적, 수평적 길이를 증가시키기 위하여 하악결합면 부위에 장부와 장붓구멍 모양을 한 골 절단술을 시행하고 광범위한 연조직경을 보존하여 골편으로의 혈류 차단을 최소화하였으며 나사를 이용한 견고한 고정을 용이하게 하였다. 이 술식은 턱을 수직적으로 증가시킬 때 두 골편 사이의 공간에 골 이식을 시행할 필요가 없으며, 금속판을 이용하지 않아도 정확한 위치에 골편을 고정하기가 용이하고, 또한 고정용 나사가 향후 골형성 부위에 위치하게 된다는 장점을 경험하게 되어 이에 한 증례를 보고하는 바이다.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.674-679
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• 1998

Small water leak experiment was carried out in liquid sodium atmosphere using a specimen of ferrite steel, which will be expected to be a material of the heat transfer tube of liquid metal fast breeder reactor. Self-plugging phenomena of leak path could be explained by the products of reaction and corrosion by sodium-water reaction. Also, re-opening mechanism of self-plugged path could be explained by the thermal transient and vibration of heat transfer tube. As a result, perfect re-opening time of self-plugged leak path was observed to be 129 minutes after water leak initiation. Re-opening shape of a specimen was appeared with double layer of circular type, and re-opening size of this specimen surface was about 2 mm diameter on sodium side.

• Neonatal Medicine
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• v.15 no.2
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• pp.160-165
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• 2008

Purpose : Cephalhematomas rarely lead to serious complications, such as skull fractures and intracranial hematomas, so CT and/or MRI scans are indicated only in cases in which depressed fractures are suspected or neurologic symptoms develop. Nevertheless, we have experienced several cases of cephalhematomas associated with intracranial hematomas in the absence of remarkable neurologic symptoms. The aim of this study was to evaluate the correlation between cephalhematomas and intracranial hematomas and determine the need for neuroimaging in infants with cephalhematomas. Methods : Infants who were admitted to the NICU with cephalhematomas and underwent neuroimaging (CT and/or MRI) between January 2002 and July 2006 were evaluated. Neuroimaging was done when the symptoms suggested the development of an intracranial hematoma. Results : Among 54 infants with cephalhematomas, 18 infants underwent neuroimaging. Six of 18 infants (33.3%) had intracranial hematomas, 4 infants had epidural hematomas, and 2 infants had subdural hematomas. Four of these 6 infants had neurologic symptoms or depressed skull fractures; 2 infants had no neurologic symptoms or depressed skull fractures. The neuroimaging was done to evaluate the cause of an excessive elevation of serum bilirubin and unexplained anemia. There were no remarkable differences between the infants with and without intracranial hematomas with respect to gestational age, birth weight, head circumference, diameter of the cephalhematoma, neurologic symptoms, and other clinical signs and symptoms. Conclusion : Based on this study, intracranial hematomas are common complications of cephalhematomas, thus more careful inspection and neuroimaging may be needed in cases of cephalhematomas in newborns.