• Journal of Trauma and Injury
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• 제19권2호
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• pp.135-142
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• 2006

Purpose: We planned to determine the diagnostic capability of focused assessment with sonography for trauma (FAST) in cases of blunt abdominal injury (BAI). Methods: A retrospective analysis of FAST sheets was performed from April 2002 to December 2004. During the study period, 135 BAI patients were evaluated with FAST at the Emergency Department of Bundang CHA Hospital. Of this group, twenty-eight patients were excluded, leaving 107 patients for analysis. Abdomen CT (computerized tomography) or exploratory laparotomy confirmed the presence of hemoperitoneum. At the secondary survey, patients underwent a three-view FAST examination (LogicQ; General Electric, Waukesha, USA) by an emergency physician, followed within 2 hours by an abdomen CT or exploratory laparotomy. The FAST examination was considered positive if it demonstrated evidence of free intra-abdominal fluid. Results: There were 45 true-positive FAST examination, 57 true-negatives, 1 false-positive, and 4 false negatives (sensitivity 91.8%, specificity 98.3%, positive predictive value 97.8%, negative predictive value 93.4%). The area under the ROC curve was 0.951 for the FAST examination. Conclusion: FAST is a highly reliable method for screening patients suspected of having BAI for the presence or absence of hemoperitoneum.

• Journal of Chest Surgery
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• 제29권9호
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• pp.1028-1030
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• 1996

동정맥류 조성술은 말기 신장질환자의 치료에 이용하는 혈액투석을 위하여 매우 중요한 역할을하며 적절한 조성술 및 장기간의 개존상태 유지는 외과의사에게 흉미있는 문제이다 동정맥루 조성술후에 발 생한 림프관종은 매우 희귀하며 림프액의 축적으로 생 긴것므로 추측된다. 림프관종은 선천성으로 혹은 수술이나 방사선조사 등과 같은 후천적 원인으로 나타나는 양성종양이며 림프조직이 분포하는 신체의 어느부분에서도 생 길 수 있다. 동맥류와 세심한 감별을 요하며 치료는 수술적 제거이다. 저자들은 59세 여자환자에서 Gore-tex이식편을 사용하여 좌측전완동맥-요측퍼정맥 동정맥루 조성술 시행후 좌측 상 완에 발생 했던, 동맥류로 오인된 거대 림프관종을 수술적 치험하였기에 보고하는바이다.

• Corrosion Science and Technology
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• 제12권5호
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• pp.227-232
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• 2013

A number of components installed in the secondary system of nuclear power plants are exposed to aging mechanisms such as FAC (Flow-Accelerated Corrosion), Cavitation, Flashing, and LDIE (Liquid Droplet Impingement Erosion). Those aging mechanisms can lead to thinning of the components. In April 2013, one (1) inch small bore piping branched from the main steam line experienced leakage resulting from wall thinning in a 1,000 MWe Korean PWR nuclear power plant. During the normal operation, extracted steam from the main steam line goes to condenser through the small bore piping. The leak occurred in the downstream of an orifice. A control valve with vertical flow path was placed on in front of the orifice. This paper deals with UT (Ultrasonic Test) thickness data, SEM images, and numerical simulation results in order to analyze the extent of damage and the cause of leakage in the small bore piping. As a result, it is concluded that the main cause of the small bore pipe wall thinning is liquid droplet impingement erosion. Moreover, it is observed that the leak occurred at the reattachment point of the vortex flow in the downstream side of the orifice.

• 설비공학논문집
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• 제12권9호
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• pp.843-852
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• 2000

The flow characteristics and the heat transfer rate on a surface by interaction of a pair of vortices were studied experimentally. The test facility consisted of a boundary-layer wind tunnel with a vortex introduced into the flow by half-delta winglet protruding from the surface. In order to control the strength of the longitudinal vortices, the angles of attack of the vortex generators were varied from $\pm20\;degree\;to\;\pm45$ degree, but spacings between the vortex generators were fixed to 4 cm. The 3-dimensional mean velocity measurements were made using a five-hole pressure probe. Heat transfer measurements were made using the thermochromatic liquid to provide the local distribution of the heat transfer coefficient. By using the method mentioned above, the following conclusions were obtained from the present experiment. The boundary layer was thinned in the regions where the secondary flow was directed toward the wall and thickened where it was directed away from the wall. The peak augmentation of the local heat transfer coefficient occurred in the downwash region near the point of minimum boundary-layer thickness.

• 한국전산유체공학회지
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• 제7권3호
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• pp.17-26
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• 2002

Computational fluid dynamic(CFD) analysis has been frequently applied to the waste incinerators to understand the flow performance for various design and operating parameters. Since the computational modeling inevitably requires many simplifications and complicated sub-models, validity of the results should be carefully evaluated. In this study, major computational modeling and procedure of usual simulation methods for the grate-type waste incinerators were assessed. Usual simulation method does not explicitly incorporate the waste combustion, simply by assuming the combustion gas properties from the waste bed which is treated as an inlet plane. However, effect of this arbitrary assumption on the overall flow pattern is not significant, since the flow pattern is dominated by strong pattern of jet flows of the secondary air. Thus, this method is valid in understanding the effect of flow-related parameters. In analyzing the results, deriving conclusive information directly from temperature and chemical species concentration should be avoided, since the model prediction for the gaseous reaction and the radiation reveals significant discrepancies against the actual phenomena. Use of quantitative measures such as residence time is very efficient in evaluating the flow performance.

• 대한수의학회지
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• 제48권1호
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• pp.93-98
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• 2008

A 6-year-old female Boston terrier dog was presented with seizure episode, forelimb paraparesis, excessive panting, and ataxia. On physical and neurological examination, episcleral vessel engorgement, delayed postural reaction, delayed pupillary light reflex (both direct and consensual), and crossed forelimb were noted. Serum biochemical profiles were not remarkable other than mildly elevated hepatic enzymes. On cerebrospinal fluid analysis, elevated protein concentration was observed. In magnetic resonance imaging scans, the left frontal brain lesion with ring enhancement strongly suggested the presence of intracranial tumor. Concurrently, secondary hydrocephalus and syringomyelia were also observed. The dog was euthanized at 4 months after initial presentation because of aggravated neurological signs. This case was definitely diagnosed as an intracranial anaplastic oligodendroglioma based on postmortem histopathologic examination.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.414-418
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• 2005

A finite element model is developed for the numerical simulation of bed elevation change in a curved channel. The SU/PG (Streamline-Upwind/Petrov-Galerkin) method is used to solve 2D shallow water equations and the BG (Bubnov-Galerkin) method is used for the Exner equation. For the time derivative terms, the Crank-Nicolson scheme is used. The developed model is a decoupled model in a sense that the bed elevation does not change simultaneously with the flow during the computational time step. The total load formula with is used for the sediment transport model. The slip conditions are described along the lateral boundaries. The effects of gravity force due to geometry change and the secondary flows in a curved channel are considered in the model. For the verification, the model is applied to two laboratory experiments. The first is $140^{\circ}$ bended channel data at Delft Hydraulics Laboratory and the second is $140^{\circ}$ bended channel data at Laboratory of Fluid Mechanics of the Delft University of Technology. The finite element grid is constructed with linear quadrilateral elements. It is found that the computed results are in good agreement with measured data, showing a point bar at the inner bank and a pool at the outer bank.

• 한국해양공학회지
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• 제24권5호
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• pp.8-15
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• 2010

The flow around a two-dimensional, rectangular cylinder that is freely falling in a channel was simulated using the immersed boundary method with direct forcing to determine the interactions between the fluid and the structure. The results of the present study were in good agreement with previous experimental results. Regardless of the H/L ratio (where H and L are the height and width of the rectangular cylinder, respectively), the flow structures had essentially the same pattern as the two symmetrical circulations that form about the horizontal center of the cylinder, with those centers located at each lateral position near the wake. When the cylinder approaches very close to the bottom, a jet-like flow appeared between the bottom of the rectangular cylinder and the channel. When the jet-like flow goes through the channel, surrounding fluids are sucked into this jet, forming the secondary vortices.

• 한국군사과학기술학회지
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• 제6권4호
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• pp.124-131
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• 2003

When a secondary gaseous flow is injected vertically into a supersonic flow through circular nozzle, a complicated structure of flow field is produced around the injection area. The interaction between the two streams produces a strong bow shock wane on the upstream side of the side-jet. The results show that bow shock wave and turbulent boundary layer interaction induces the boundary layer separation in front of the side-jet. This study is to analyze the structure of flow fields and distribution of surface pressure on the flat plate according to total pressure ratio using a supersonic cold-flow system and also to study the control force of affected side-jet. The nozzle of main flow was designed to have Mach 2.88 at the exit. The injector has a sonic nozzle with 4mm diameter at the exit of the side-jet. In experiments, The oil flow visualization using a silicone oil and ink was conducted in order to analyze the structure of flow fields around the side-jet. The flow fields are visualized using the schlieren method. In this study, a computational fluid dynamic solution is also compared with experimental results.

• Journal of Korean Neurosurgical Society
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• 제30권1호
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• pp.81-84
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• 2001

Pneumocephalus is exceedingly rare in the absence of trauma or recent surgery. It is most commonly seen after severe head injury, with disruption of the dura and subsequent cerebrospinal fluid leakage. Intracranial air has also been reported as a complication of shunting. This may be secondary to intermittent shunt failure or a persistent communication between the extracranial and intracranial space that permits the entrance of air. In the present case, air appeared to enter the ventricular system through the fistula that connected the frontal sinus. This air replaced the CSF being drained into the peritoneal cavity by the shunt. The decrease of intracranial pressure after a shunt might play a role in causing pneumocephalus. We report a case of tension pneumocephalus after shunting for hydrocephalus as a life-threatning complication.