• 한국전산유체공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.195-199
• /
• 2005

Wave breaking phenomenon near the fore body of a ship is numerically simulated. The ship advance with uniform velocity in calm water. For the simulation, incompressible Navier-Stokes equations and continuity equation are adopted as governing equations. The simulation is carried out in staggered variable mesh system with finite difference method. Marker and Cell(MAC) method and Marker-Density method are employed to track the free surface. Body boundary conditions are satisfied with the adoption of porosity method and no-slip condition on the hull surface. The ship model has a wedge type fore-body, and the computational domain is an appropriate region around the fore-body. The computation results are compared with some experimental results. Also the difference of the free surface tracking methods are discussed.

• Journal of Chest Surgery
• /
• v.17 no.3
• /
• pp.448-455
• /
• 1984

Coarctation of the Aorta is a congenital constriction of aorta of varying degree, usually located at or near the aortic ismuth with frequent associations of other cardiac anomalies. Various modes of surgical corrections, such as resection and end-to-end anastomosis, graft interposition, angioplasty using prosthetic patch or subclavian flap have been used according to the status of coarctation and age of the patient. We have experienced two cases of surgically treated coarctation of the aorta, one of which was preductal coarctation with hypoplastic aortic arch and ventricular septal defect in a 4 year old boy, and the other case was juxtaductal type with aortic regurgitation. Subclavian flap angioplasty with additional pulmonary artery banding procedure was done in the first case and wedge resection with end-to-end anastomosis and aortic valve replacement [St. Jude valve, 23mm] 20 days later of first operation in the other case. The first case developed massive tarry stool on 3rd POD, probably due to mesenteric arteritis with resultant bowl ecrosis, and expired the next day. Recovery was uneventful with the second case.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.38-43
• /
• 2001

The interfacial adhesive joining characteristics of the foams are very important for the structural integrity of sandwich structures. Peel strength is one of the best criteria for the interfacial characteristics of the sandwich structures and peel energy is most commonly used for the interfacial characteristics. The peel strength is the first peak force per unit width of bond line required to produce progressive separation by the wedge or other crack opening type action of two adherends where one or both undergo significant bending and the peel energy is the surface active energy per unit width of bond line. In this work, to investigate the strengthening effect of resin treatment on the interfacial surface of foam material, peel strength and peel energy of epoxy resin treated polyurethane foam core sandwich structures were obtained by the cleavage peel tests and compared with those of non surface treated polyurethane foam core sandwich structures.

• Proceedings of the KOSOMBE Conference
• /
• v.1997 no.11
• /
• pp.176-179
• /
• 1997

In this paper, We developed a radiation therapy planning system using photon beams. Firstly We accomplished simulation on the regular field. Then it has been modified step by step to handle the irregular field, wedge filter, and inhomogeneous field. This system is equipped with useful user interface and database. This system is implemented in Visual C++ as a window-based application program.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.10 no.2
• /
• pp.56-62
• /
• 1990

Surface Acoustic Waves(SAW) are generated on silicon wafer and $YZ-LiTaO_3$ substrate and are detected by noncontact method. As wave sources two kinds of transducers are used : the wedge-type of 20.0 MHz and fabricated Interdigital Transducer(IDT) of 20.8 MHz. SAW are modulated by the optical chopper frequency and are syncronized with a laser beam. In signal processing, intensity variations of light due to the intensity of SAW are analyzed using lock- in amplifier. From the results, corresponding to the applied input power, the intensity variations of a deflected light by corrugations on the substrates are increased and saturation phenomenon is observed.

• Transactions of Materials Processing
• /
• v.8 no.2
• /
• pp.178-187
• /
• 1999

The Cross rolling between flat jaws, as a kind of hot forging, is the forming method to make the axisymmetric multi-step shaft by its rotation and pressure between flat jaws which move in opposite direction. The purpose of this study is to propose the optimal geometric data for shape development of the forward forming region. All data described on this paper are quantified by experiment from initial shape design to final shape development. As the result, proper geometric data are proved that lenth of the first forming area in the forward forming region is 1.5 times larger than circumference of work-piece and the progress angle changes 3 times smoothly.

• Journal of Chest Surgery
• /
• v.14 no.3
• /
• pp.218-224
• /
• 1981

Acute gastric volvulus is one of the most fatal complications of the eventration of diaphragm and require emergency surgical treatment unless it is possible to pass a nasogatric tube. This 10 year old female patient was admitted because of severe abdominal pain and marked abdominal distention before about 3 days. On chest P-A and plain abdomen, there were the elevation of the left hemidiaphragm and marked dilatation of stomach and the triad of symptoms emphasized by Bochdalek in 1904 was present. Emergency operation [wedge resection of necrotic area of stomach and gastropexy after gastric decompression and plication of diaphragm] was performed. The type of gastric volvulus was organo-axial rotation, in which the stomach rotated around the line that connects the cardia with the pylorus [Fig. 4].

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05d
• /
• pp.404-404
• /
• 1996

In order to ensure a concrete expansion anchor is suitable for a given application, the load resistance behavior of the anchor must be known. ASTM E488 provides a standard method of testing expansion anchors for static and dynamic loads. Due to the many types of anchors available commercially and the large variability of applications, the ASTM does not delineate all details or requirements necessary to comprehensively determine the dynamic load behavior of concrete expansion anchors. A test program is presented in this paper which was developed and implemented to determine the cyclic load behavior of wedge-type concrete expansion anchors. Test results are also presented along with a discussion of the behavior of anchors, and their suitability for use.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1998.04a
• /
• pp.22-22
• /
• 1998

기존의 공력 조타에 의한 비행 자세 제어 방법은 속도의 2승에 비례하는 제어력을 발생하지만, TVC(Thrust Vector Control)를 이용하면 추력 방향을 변경하여 제어력을 얻음으로써 방향 제어에 보다 월등한 성능을 발휘하는 것으로 알려져 있다. 후자의 방법으로는 저속도 경우와 공기가 희박한 고 고도에서도 충분한 제어력을 얻을 수 있다. 보다 효율적인 제어력을 얻기 위해서는 TVC 방법이 우수하지만 그 성능에 대해서는 충분한 자료가 없는 것이 현재의 상태이다. 제트 베인 방식의 TVC는 베인이 직접 고온 고속의 가스 흐름 내에서 작용하기 때문에 편향추력 발생 측면에서 아주 우수한 방식이며 추력 편향각, 추력 손실 등의 유체역학적인 특성은 제트 베인의 형상, 위치 등으로 결정된다.

• Journal of Chest Surgery
• /
• v.5 no.2
• /
• pp.135-140
• /
• 1972

Papilloma of the upper respiratory tract, particularly larynx and vocal cords are relatively common disease. However, solitary papilloma of the bronchus is extremely rare condition and only a handful cases were reported in the literature. The patient is a 39 year old housewife who has been suffering from productive cough and occasional hemoptysis in the past one year. X-ray of the chest showed complete atelectasis of the right upper lobe. Bronchography revealed a hemispherical protruding mass in the right main bronchus with complete occlusion of the upper lobe bronchus. Bronchoscopy showed a whitish friable mass in the lumen of the right main bronchus biopsy of which was reported as benign papilloma. Right upper lobectomy together with wedge resection of the portion of right main bronchus to include the tumor was done. Cut-edges of the bronchus were stitched together with interrupted fine dacron sutures. During this procedure, right main bronchus was gently clamped with non-crushing Satinsky type clamp. Patient has had uneventful recovery from surgery and was discharged without symptom. Patientis doing well three months following the operation.