• Journal of the Korean Society of Visualization
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• v.8 no.2
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• pp.31-39
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• 2010

Hysteresis is an effect by which the order of previous events influences the order of subsequent events. Hysteresis phenomenon of supersonic internal flows with shock waves has not yet been clarified satisfactorily. In the present study, experiments are carried out on internal flow in a supersonic nozzle to clarify the hysteresis phenomena for the shock waves. Flow visualization is carried out separately on the straight and divergent channels downstream of the nozzle throat section. Results obtained were compared with numerically simulated data. The results confirmed hysteresis phenomenon for shock wave in the Laval nozzle at a certain specific condition. The relationship between hysteresis phenomenon and the range of the rate of change of pressure ratio with time was shown experimentally. The existence of hysteretic behavior in the formation, both the location and strength, of shock wave in the straight part of the supersonic nozzle with a range of pressure ratio has also been confirmed numerically.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.524-531
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• 2011

The cryogenic vessel, storing a liquified solutions as LOX and $LN_2$, consists of a external vessel, internal vessel, thermal insulator and internal support. The internal support should be satisfied with mechanical strength not only to support weight of internal tank but also to maintain uniform space between external and internal tank in spite of external mechanical shock. However, excessive structure design of internal supports is able to increase the amount of heat conduction and the rate of vaporization. The thermal insulator, filled with space between a external and internal vessel, reduces the rate of heat transfer and guarantees the standing time of cryogenic vessel. Especially powder type of insulator has low thermal conductivity and reduce the specification of structure design. In order to evaluate the effect of insulator on structure design, the experiment set-up simulated cryogenic vessel was tested in shock environment according to thermal insulator. As a result, the behavior of internal support under external shock was understood and the design criteria was able to be suggested.

• Journal of Veterinary Science
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• v.24 no.6
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• pp.77.1-77.7
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• 2023

Antibiotics are known to be able to cause hypersensitivity reactions through various mechanisms. We present a case of drug-induced immune thrombocytopenia (DITP) and anaphylactic shock occurring simultaneously in a dog after the administration of two classes of antibiotics, namely trimethoprim-sulfamethoxazole (TMP-SMX) and amoxicillin-clavulanate (AMC). The patient recovered completely from DITP on discontinuation of TMP-SMX and the anaphylactic shock caused by AMC was treated with intensive care. DITP is a rare adverse drug reaction (ADR), and anaphylactic shock is a life-threatening ADR. This is the first case report of a dog manifesting two types of hypersensitivity reactions caused by two antibiotics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.357-361
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• 2010

When high-pressure gas is exhausted through nozzle exit to the atmosphere, expanded supersonic jet is formed with the Mach disk at a specific condition. In two-dimensional supersonic jets, the hysteresis phenomenon of the reflected shock waves is found to occur under quasi-steady flow conditions. Transitional pressure ratio between the regular reflection and Mach reflection in the jet is affected by this phenomenon. In the present study, experiments are carried out on internal flow in a supersonic nozzle to clarify the hysteresis phenomena for the shock waves and to discuss its interdependence on the rate of the change of pressure ratio with time. Flow visualization is carried out separately on the straight and divergent channels downstream of the nozzle throat section. The influence that the hysteresis phenomena have on the location of shock wave in a supersonic nozzle is also investigated experimentally.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.6
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• pp.36-44
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• 2021

Numerical analysis was performed on the shock wave-boundary layer interaction generated in the internal flow path of the curved interstage of the scramjet engine flight test vehicle. For numerical analysis, the turbulence model k-ω SST was used in the compressibility Raynolds Averaged Navier Stokes(RANS) equation. Representatively, the separation bubbles on the upper wall of the nozzle, the interaction between the concave shock wave and the boundary layer, and the shock wave-shock wave interaction at the edge were captured. The analysis result visualizes the shock wave-boundary layer interaction of the curved internal flow path to enhance understanding and suggest design considerations.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.285-289
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• 2017

Pheochromocytoma can present with various symptoms including cardiogenic shock and cardiac arrest. Particularly, in cases of cardiogenic shock of unknown origin, pheochromocytoma should be considered. A 20-year-old woman without any medical history visited our emergency department due to nausea, vomiting, headache, and chest pain. Echocardiography revealed severe left ventricular dysfunction. Mechanical ventilation and veno-arterial extracorporeal membrane oxygenation (ECMO) were implemented owing to her unstable vital signs. For unstable vital sign and cardiogenic shock in a young woman without any previous medical history, pheochromocytoma was considered and diagnosed based on elevated levels of catecholamine derivatives in a 24-hour urine sample. Cardiac function recovered and ECMO was discontinued on the 5th day of hospitalization. She later underwent an elective adrenalectomy and no recurrence was found during the follow-up period. We reported a case of pheochromocytoma which was presented with cardiogenic shock in a young woman with no concomitant disease, and successfully treated with ECMO followed by an elective adrenalectomy.

• Tuberculosis and Respiratory Diseases
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• v.57 no.5
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• pp.465-469
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• 2004

Exudative pleural effusion can arise from pneumonia, tuberculosis, cancer, etc. Early drainage is needed for prevention of complications such as pleural fibrosis, thickening, bronchopleural fistulae and decline of lung function. Intrapleural Instillation of fibrinolytic enzymes has been used for 50years as an adjunct in the removal of fibrous material, hematoma and pus from the thoracic cavity. By the local fibrinolytic effect on fibrinous exudates within the pleural space, fibrinolytic agent has improved results of chest tube or pig tail drainage. But there were no controlled randomized studies, so significant controversy exists concerning the efficacy of this therpy, especially tuberculous pleurisy. Furthermore about complication, severe spontaneous bleeding has not been reported with intrapleural urokinase. Intrapleural fibrinolytic enzymes has shows no systemic complication. When it is administrated intravenously, not into intrpleural space, major bleeding is reported about 1-3% of patient, especially they had systemic disease, such as coagulation abnormalities. This case report presents a patient who suffered major hemothorax induced hypovolemic shock following the administration of 100,000 units of urokinase intrapleurally. He was 25-year old male with tuberculosis pleurisy without systemic illness demonstraion.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.3
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• pp.31-40
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• 2020

The structure and dynamics of multiple shock waves are studied numerically using a finite volume solver for a model with nozzle exit Mach number of 1.75. At first, the shock variation based on images were analyzed using a Matlab program then later to the wall static pressure variation. The amplitude and frequency variation for multiple shock waves are analyzed. The cross-correlation between the shock location suggests that the first and the second shocks are well correlated while the other shocks show a phase lag in the oscillation characteristics. The rms values of pressure fluctuations are maximum at the shock locations while the other parts in the flow exhibit a lower value os standard deviation.

• Journal of Yeungnam Medical Science
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• v.31 no.1
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• pp.17-20
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• 2014

Iatrogenic femoral artery pseudoaneurysm is a complication in patients undergoing catheterization. The risk increased when large-bore sheaths, concomitant anticoagulation therapy, and antiplatelet therapy are used during the intervention. Ultrasound-guided thrombin injection has become the treatment of choice. Rapid expansion, rupture, infection, and mass effect resulting in distal or cutaneous ischaemia or peripheral neuropathy, as well as failure of other treatment options are all indications for surgery. We report a 48-year-old man who developed hemorrhagic shock due to femoral pseudoaneurysm rupture after coronary angiography, and successfully treated by ultrasound-guided thrombin injection.

• Tuberculosis and Respiratory Diseases
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• v.67 no.6
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• pp.491-498
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• 2009

Severe sepsis and septic shock are major healthcare problems with high mortality, ranging from 20% to 60%, affecting millions of individuals around the world each year. The speed and appropriateness of therapy administered in the initial hours after severe sepsis develops have an important impact on the outcome. In 2004, an international guideline that the bedside clinician could use to improve the outcomes in severe cases of sepsis and septic shock was published. Several landmark studies recently demonstrated that therapeutic strategies may reduce mortality substantially. The "Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock: 2008", using a new evidence-based methodology system for assessing the quality of evidence and the strength of the recommendations, was updated. The revised version is based on an updated search into 2007. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improving the outcomes of critically ill patients. We review the treatment guidelines of sepsis and septic shock.