• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.1
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• pp.11-21
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• 1998

A numerical study is made on the ice-formation for water flow inside a stenotic tube. The study takes into account the interaction existing between the laminar flow and the stenotic port in the circular tube. In the solution strategy, the present study is substantially distinguished from the existing works In that the complete set of governing equations in both the solid and liquid regions are resolved. In a channel flow between parallel plates, the agreement of predictions and available experimental data is very good. Numerical results are mainly obtained by varying the height and length of a stenotic shape and additionally for several temperatures of the wall and inlet of tube. The results show that the shape of stenotic port has the great effect on the thickness of the solidification layer in the tube. As the height of a stenosis grows and the length of a stenosis decreases, the ice layer thickness near the stenotic port is thinner due to backward flow caused by the sudden expansion of water tunnel. It is also found that the ice layer becomes more fat In accordance with Reynolds number and the temperature of the wall and inlet of tube decreased.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1269-1281
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• 1989

본 연구에서는 H를 고정하고 L을 변화시켜가며 내부의 유동구조가 어떻게 변하는가를 살펴보고, 특히 재부착이 일어나는 경우에는 급확대 부분만 존재하는 기존 실험결과와 비교분석하여 하류의 급축소부분이 전체 유동구조에 어떤 영향을 미치는가를 살펴보고자 한다. 실험에서 사용된 작동유체는 공기이며, 입구관 직경은 110mm, 급확대점과 급축소점사이의 연결부 직경은 220mm, 연결부의 길이는 L=300, 600 그리고 900mm의 3가지를 선택하였으며 기준속도는 입구관의 중심속도로 9.71 m/s이다. 입구직경(110mm)을 기준으로 한 Reynolds 수는 $R_{e}$=73,000 이고 입구관반경과 연결부반경의 차이인 계단높이(H=55mm)를 기준으로 하면 $R_{e=36}$ ,500이다. 연결부 의 급확대부분에서 입구관반경을 기준으로 한 반경확대비는 2이고 급축소부분의 반경 축소비는 1/2이다. 측정항목은 유동방향의 벽면압력분포, 유동방향의 평균속도분포 및 난류강도 등이며, L=900mm인 경우는 반경방향과 원주방향의 난류강도, Reynolds 전단응력도 측정되었다.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.3
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• pp.68-71
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• 2008

Transdermal and topical drug delivery with minimal tissue damage has been an area of vigorous research for a number of years. Our research team has initiated the development of an effective method for delivering drug particles across the skin (transdermal) for systemic circulation, and to localized (topical) areas. The device consists of a micro particle acceleration system based on laser ablation that can be integrated with endoscopic surgical techniques. A layer of micro particles is deposited on the surface of a thin metal foil. The rear side of the foil is irradiated with a laser beam, which generates a shockwave that travels through the foil. When the shockwave reaches the end of the foil, it is reflected as an expansion wave and causes instantaneous deformation of the foil in the opposite direction. Due to this sudden deformation, the microparticles are ejected from the foil at very high speeds, and therefore have sufficient momentum to penetrate soft body tissues. We have demonstrated this by successfully delivering cobalt particles $3\;{\mu}m$ in diameter into gelatin models that represent soft tissue with remarkable penetration depth.

• Journal of Digital Contents Society
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• v.9 no.4
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• pp.707-715
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• 2008

The ocean ecosystem and the marine farms were damaged after latest oil spill in Taean. They suffered heavily due to the expansion of the red tide on the coast and the sudden changes in water temperature. We should develop the way to deal with various factors to reduce the damage. In this paper, real time data with which are supplied us through many kinds of sensors on measure equipments will be processed to the visualized shape. Simple numeric data and 2D graph will be changed 2D or 3D graphic objects and animations using WPF, a new effect method in user interface area. This visualization system for environmental data shows us various pictures and offers multimedia data communication.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.711-714
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• 2008

The objective of this paper is to know the characteristics of pressure through a simplified typical carburetor used in small engines at the different throttle opening conditions. The carburetor is the device responsible for creating the right air-fuel mixture according to the different engine operating conditions. It is activated by the static or the dynamic pressure. The carburetor dummy is geometrically similar of LPG brush-cutter engine's diaphragm carburetor and is made of acrylic. Suction system gives body to crankcase vacuum using the vacuum pump and throttle opening conditions are controled by transfer device. Carburetor venturi throat and fuel charging tube diameter is each 20mm, 4.1mm. The result of the work presents an unprecedented phenomenon of suction pressure variation inside the carburetor venturi. It is predicted that these unprecedented pressure variation be caused by minor losses; sudden contraction or expansion, open or partially closed and so on.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.211-215
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• 2010

Continuous contraction and expansion of disk brake can be due to friction and temperature difference at repeated sudden braking. As serious vibration at disk is produced, the braking force will be changed ununiformly and braking system can not be stabilized. Temperature and heat flux at disk brake are investigated by structural and thermal analysis in this study. The maximum equivalent stress and displacement are shown respectively at the ventilated hole and the lower part of disk plate. At thermal analysis of initial state, temperature on disk plate is distributed from $95.9^{\circ}C$ to $100^{\circ}C$. The maximum heat flux of $0.0168W/mm^2$ is shown at the inner friction part between disk plate and pad. At thermal analysis of transient state, temperature on disk plate is distributed from $95^{\circ}C$ to $96.5^{\circ}C$ after 100 second. The maximum heat flux of $0.0024W/mm^2$ is also shown at the inner friction part between disk plate and pad. By comparing with initial state, the temperature on disk plate is more uniformly distributed and heat flux is more decreased by 7 times at transient state.

• Journal of Chest Surgery
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• v.14 no.2
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• pp.140-143
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• 1981

Thymolipoma is extremely uncommon benign mediastinal tumor consisting of fatty and thymic tissue. Only 50 verified cases have been reported in the world literatures. This one case is the first reported example of surgically treated thymolipoma associated with spontaneous pneumothorax. A thirty-two year old male patient had been in good health until two days prior to admission, when he noted sudden dyspnea associated with an aching pain over the left precordium. The dyspnea and chest pain had become progressively worse. The physical examination revealed that left hemithorax was tympanic sound on percussion and absence of breathing sound on auscultation and point of maximal impulse was located on the 4th intercostal space at the left sternal border. Emergency closed thoracostomy was performed under the impression of tension type spontaneous pneumothorax of the left lung. After closed thoracostomy, point of maximal impulse was not changed inspire of full expansion of the left lung and chest X-ray was strongly suggested pericardial effusion or cardiomegaly which couldn`t account for by clinical course and hemodynamic evidence. EKG, echocardiogram, bronchofiberoscophy, bronchogram and diagnostic thoracentesis was performed. On Dec. 8, 1980, operation was performed under the impression of mediastinal tumor in the anterior mediastinum. At left posterolateral thoractomy, a large fatty mass, measuring 35 x 27 x 13 Cm in dimension and weighing 3350 gm, was resected and multiple bullae on the apicoposterior segment of the left upper lobe was resected and continuously sutured. The pathologic diagnosis of the fatty mass was thymolipoma. The postoperative course was uneventful and discharged in good general conditions.

• Journal of Chest Surgery
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• v.14 no.2
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• pp.135-139
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• 1981

Thymolipoma is extremely uncommon benign mediastinal tumor consisting of fatty and thymic tissue. Only 50 verified cases have been reported in the world literatures. This one case is the first reported example of surgically treated thymolipoma associated with spontaneous pneumothorax. A thirty-two year old male patient had been in good health until two days prior to admission, when he noted sudden dyspnea associated with an aching pain over the left precordium. The dyspnea and chest pain had become progressively worse. The physical examination revealed that left hemithorax was tympanic sound on percussion and absence of breathing sound on auscultation and point of maximal impulse was located on the 4th intercostal space at the left sternal border. Emergency closed thoracostomy was performed under the impression of tension type spontaneous pneumothorax of the left lung. After closed thoracostomy, point of maximal impulse was not changed inspire of full expansion of the left lung and chest X-ray was strongly suggested pericardial effusion or cardiomegaly which couldn`t account for by clinical course and hemodynamic evidence. EKG, echocardiogram, bronchofiberoscophy, bronchogram and diagnostic thoracentesis was performed. On Dec. 8, 1980, operation was performed under the impression of mediastinal tumor in the anterior mediastinum. At left posterolateral thoractomy, a large fatty mass, measuring 35 x 27 x 13 Cm in dimension and weighing 3350 gm, was resected and multiple bullae on the apicoposterior segment of the left upper lobe was resected and continuously sutured. The pathologic diagnosis of the fatty mass was thymolipoma. The postoperative course was uneventful and discharged in good general conditions.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.100.2-100.2
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• 2011

The dynamical evolution of the Earth's magnetosphere loaded with a transiently enhanced ring current is studied by numerical magnetohydrodynamic (MHD) simulation. Two cases with different values of the primitive ring current are considered. In one case, the initial ring current is strong enough to create a magnetic island in the magnetosphere. The magnetic island readily reconnects with the earth-connected ambient field and is destroyed as the system approaches a steady equilibrium. In the other case, the initial ring current is not so strong, and the initial magnetic field configuration bears no magnetic island, but a wake of bent field lines, which is smoothed out through the relaxing evolution of the magnetosphere. The relaxation time of the magnetosphere is found to be about five to six minutes, over which the ring current is reduced to about a quarter of its initial value. Before reaching a steady state, the magnetosphere is found to undergo an overshooting expansion and a subsequent contraction. Fast and slow magnetosonic waves are identified to play an important role in the relaxation toward equilibrium.

• Animal cells and systems
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• v.15 no.3
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• pp.243-249
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• 2011

The genetic diversity and population history of the Asian shore crab, Hemigrapsus sanguineus, were investigated with a nucleotide sequence analysis of 536 base pairs (bp) of the mitochondrial cytochrome c oxidase subunit I gene (COI) in 111 samples collected from four populations in Korea and one in Japan. In total, 28 haplotypes were defined by 27 variable nucleotide sites in the COI region examined. The observed haplotypes had a shallow haplotype genealogy and no geographical associations. Most of the populations had high haplotype diversity (0.656-0.788) and low nucleotide diversity (0.00165-0.00244), and significant negative values for Fu's $F_S$, suggesting rapid and recent population growth from an ancestral population and sudden population expansion. The pairwise fixation indices ($F_{ST}$) estimated with the exact test and the migration rates indicate that substantial gene flow occurs among these populations as a result of sea currents, except between the Yellow Sea coast of Korea (BUA) and the Pacific Ocean coast of Japan (JPA). These two populations (BUA and JPA) showed significant genetic differentiation and low migration rate.