• 한국임상수의학회지
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• 제26권1호
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• pp.81-85
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• 2009

A spayed female, 8-year-old, maltese, weighing 1.84 kg with a history of acute severe vomiting, anorexia, depression for 2 day was referred. An abdominal mass was palpated with abdominal pain on physical examination. Radiographic findings included two soft tissue density masses in the mid-abdominal cavity and gas dilated colon. Ultrasonographs showed one heterogeneous hypoechoic round mass including intestinal wall. There were loss of normal wall layering and motility and absence of internal lumen of the intestinal wall. And another heterogeneous hyperechoic mass was identified to the medial side of the intestinal mass. Based on clinical signs, image findings, and the result of fine needle aspiration, intestinal obstruction due to alimentary lymphoma was diagnosed. On surgery, a cecal lymphoma and mesenteric lymphadenopathy were confirmed and the cecal mass was resected.

• 대한기계학회논문집B
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• 제20권10호
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• pp.3313-3321
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• 1996

A fundamental study in cooling and solidification process focused on ice storage was performed, including the interesting phenomena of density inversion, supercooling and dendritic ice. A numerical study was performed for natural convection and ice formation in the cooling and freezing processes with supercooling in a space between double cylinders. When water was cooled under the freezing point by a cooling wall in a cavity, solidification was not started at once, but a subcooled region was formed near the wall. Especially, when the cooling rate was low, subcooled region extended to a wide area. However, after a few minutes, supercooling is released by some triggers. Dendritic ice is suddenly formed within a subcooled region, and a dense ice layer begins to be developed from the cooling wall. Due to the difficulties, most previous studies on solidification process with numerical methods had not treated the supercooling phenomena, i.e. the case considering only the growth of dense ice. In this study, natural convection and ice formation considering existence of supercooling and dendritic ice were analyzed numerically with using finite difference method and boundary fixing method. The results of numerical analysis were well compared with the experimental results.

• Journal of Ginseng Research
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• 제16권1호
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• pp.37-43
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• 1992

Structural changes of the endosperm of Panax ginseng C.A. Meyer from fertilization to germination were investigated by light microscope. The endosperm of the ginseng seed is cellular type. Since endosperm cells adjacent embryo continuously breakdown and disappear with the elongation of embryo, the real of endosperm is gradually decreased. As the anatropous ovules of immature seed with green seed coat developes more and more, ovary cells adjacent ovary cavity become abundant by the periclinal division, their size is decreased, hypotrophy of cell wall discern, and they are gradually differentiated in seed coat. Though embryo responds strongly to basic dye at the stage of completion of endosperm formation, tissue of endosperm responds to acidic dye positively Cell wall of embryo and endosperm are composed of primary cell wall not lignified. Endosperm cells adjacent embryo begin to breakdown in the endosperm tissue of indehiscent seed before the beginning of the after-ripening. Dehiscent seed of which seed coat is opened through after-ripening represent the form as a seedling in the result of embryo developments with the formation of organs; radicle, cotyledon, plumule. Umbilifom layer represents strong positive response to the toluidine blue and the basic function. Umbiliform layer that endosperm cells breakdown and disappear is observed clearly at the periphery of the embryo cotylemon, while slightly at the periphery of the radicle.

• 대한기계학회논문집A
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• 제32권6호
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• pp.481-487
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• 2008

Rapid mold heating has been recent issue to enable the injection molding of thin-walled parts or micro/nano structures. Induction heating is an efficient way to heat material by means of an electric current that is caused to flow through the material or its container by electromagnetic induction. It has various applications such as heat treatment, brazing, welding, melting, and mold heating. The present study covers an experimental investigation of induction heating in order to rapidly raise the mold temperature. It is observed that the mold surface temperature is raised up to $200^{\circ}C$ in 2 seconds. This induction heating is applied to injection molding of a flexspline for a plastic harmonic drive, which has difficulty in cavity filling because its minimum thickness is only 0.35 mm. The induction heating is then successfully implemented on this ultra-thin wall molding by raising the mold surface temperature around the glass-transition temperature of the molding material.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2100-2105
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• 2008

A numerical analysis was conducted to predict the heat transfer characteristics of a high-temperature, high heat flux solar receiver as the end-wall angle varied. The concentration ratio of the solar receiver ranges from 200 to 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. This study deals with a solar receiver incorporating high-temperature sodium heat pipe as well as a typical one that employs a molten-salt circulation loop with the same outer dimensions. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 mm and the length was 400 mm. FLUENT, a commercial software, was employed to deal with the radiative heat transfer inside the receiver cavity and the convection heat transfer along the channels and heat pipes. The numerical results were compared and analyzed from the view point of heat transfer characteristics the solar receiver system.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.24-30
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• 1998

A directly coupled Boundary Element and Finite Element Model was applied to the dynamic analysis of a coupled acoustic silencer with vibratory wall. In this cupled BEM-FEM muffler model, the BEM model was used to discretize the acoustic cavity and the FEM model was used to discretize the vibratory wall structure. Then the BEM model was coupled with the FEM model. The results of the coupled BEM-FEM model for the dynamic analysis of the simple expansion type reactive muffler configurations with flexible walls were verified by comparing the predicted results to analytical solutions. In order to investigate the effects of the muffler's structural flexibility on its transmission loss(TL) characteristics, the results of the coupled BEM-FEM model in conjunction with the four-pole parameter theory were utilized. The muffler's TL characteristics using the BEM-FEM coupled model with flexible walls as compared to other muffler configurations was studied. Finally the muffler's TL values with respect to different wall's thickness are predicted and compared.

• Journal of Trauma and Injury
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• 제20권1호
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• pp.47-51
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• 2007

Penetrating chest trauma caused by the components of one's own car is rare in motor vehicle accidents. We experienced two cases of penetrating chest injury caused by the sideview mirror of the patient's vehicle. One was a 25-year-old man. The sideview mirror penetrated the left chest, went through the diaphragm, and ruptured the spleen. He was in shock upon arrival at the emergency room. An emergency thoracotomy and laparotomy were done. The ruptured spleen was resected, the lung and the diaphragm were debrided and repaired, and the chest wall was reconstructed. The other patient was a 57-year-old male, who was transported to our emergency room with the sideview mirror of his truck stuck into his right chest wall as the result of an accident. He also had a right Bennet's fracture and an open fracture of the right tibia. Air had been sucked into the right pleural cavity through the wound. Multiple rib fractures and lung lacerations had also occurred. Removal of the sideview mirror, repair of the lacerated lung, and reconstruction of chest wall were done immediately. Both patients recovered without complication and were discharged.

• 대한기계학회논문집B
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• 제20권3호
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• pp.1083-1095
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• 1996

Shock wave/boundary layer interaction frequently causes the shock wave to oscillate violently and thus the global flow field to unstabilize. In order to stabilize the shock wave system in the diffuser of a supersonic wind tunnel, the present study attempted to control the shock oscillations by using a passive control. A porous wall with the porosity of 19.6% was mounted on a shallow cavity. Experiment was made by means of schlieren optical observation and wall pressure measurements. The flow Mach number just upstream the shock system and Reynolds number based on the turbulent boundary layer thickness were 2.1 and 1.8 * 10$\^$6/, respectively. The results show that the present passive control method on the shock wave/boundary layer interaction in the supersonic diffuser can significantly suppress the oscillations of shock system, especially when the shock system locates at the porous wall.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.428-446
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• 1997

Restorative procedures can lead to weakening tooth due to reduction and alteration of tooth structure. It is essential to prevent fractures to conserve tooth. The resistance to fracture of the restored tooth may be influenced by many factors, among these are the cavity dimension and the physical properties of the restorative material. The placement of direct composite resin restorations has generally been found to have a strengthening effect on the prepared teeth. It is the purpose of this investigation to study the relationship between the cavity isthmus and the fracture resistance of a tooth in composite resin restorations. In this study, MO cavity was prepared on maxillary first premolar. Three dimensional finite element models were made by serial photographic method and isthmus(1/4, 1/3, 1/2 of intercuspal distance) were varied. Two types of model(B and R model) were developed. B model was assumed perfect bonding between the restoration and cavity wall and R model was left unfilled. A load of 500N was applied vertically at the first node from the lingual slope of the buccal cusp tip. This study analysed the displacement, 1 and 2 direction normal stress and strain with FEM software ABAQUS Version 5.2 and hardware IRIS 4D/310 VGX Work-station. The results were as follows : 1. Displacement of buccal cusp in R model occurred and increased as widening of the cavity, and displacement in B model was little and not influenced by cavity width. 2. There was a significant decrease of stress resulting in increase of fracture resistance in B model when compared with R model. 3. With the increase of the isthmus width, B model showed no change in the stress and strain. In R model, the stress and strain increased both in the area of buccal-pulpal line angle and the buccal side of marginal ridge, therefore the possibility of crack increased. 4. The stress and strain were distributed evenly on the tooth in B model, but in R model, were concentrated on the buccal side of the distal marginal ridge and buccal-pulpal line angle, therefore the possibility of fracture increased.

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.107-119
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• 1990

The purpose of this study was to evaluate the marginal adaptability of the amalgam restorations in applying the cavity varnish (Copalite$^{(R)}$) and dentin bonding agent (Scotchbond 2$^{(R)}$) under the scanning electron microscope. For this study, eighteen sound extracted human molars were selected. Class I cavities in 12 teeth and class V cavities in 6 teeth were prepared using an air turbine with No. 701 tungsten carbide bur and finished using a low speed handpiece with No. 557 fissure bur. The prepared specimens were then divided into three groups including 4 class I cavities and 2 class V cavities in each group and restored as follows ; Group I. All the prepared cavities were restored with amalgam only (Control). Group II. Two layers of Copalite$^{(R)}$ cavity varnish were applied to the cavities with a gentle stream of air after each application and cavities were restored with amalgam. Group III. The enamel cavity margins were etched with 37% phosphoric acid gel for 60 sec., rinsed for 30 sec. and dried. One layer of visible lightcured Scotchbond Dental Adhesive$^{(R)}$ was applied and immediately cured for 20 seconds with visible light-cure unit and cavities were restored with amalgam. All the specimens were cut at the neck of the teeth and the occlusal halves of specimens were sectioned buccolingually in the longitudinal axis centering the amalgam restorations, using the disk. The cut specimens were ground with sandpapers (400, 600, 800, 1000 grit), and cleaned for 5 minutes in the ultrasonic cleaner (Brason Co. U.S.A.). In the cut surfaces, the amalgam - tooth interfaces were examined under the scanning electron microscope (JSM, 35C type, JEOL). The obtained results were as follows ; 1. The amalgam-tooth interfaces were reduced more significantly in the Copalite$^{(R)}$ and Scotchbond 2$^{(R)}$ application group than in the control group. 2. In the class I cavities, the Scotchbond 2$^{(R)}$ application group showed the findings similar to the Copalite$^{(R)}$ application group in the cavity floor, and the marginal adaptability was better in the side wall than in the cavity floor. 3. In the class I cavities, the Scotchbond 2$^{(R)}$ application group showed better marginal adaptability in the occlusal margin than in the gingival margin. 4. The marginal adaptability was in the order of the Scothbond 2$^{(R)}$ application group, the Copalite$^{(R)}$ application group and the control group.