• 한국가시화정보학회지
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• 제8권2호
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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.

• 한국군사과학기술학회지
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• 제14권3호
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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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• 제24권6호
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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.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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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.

• 한국추진공학회지
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• 제25권6호
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• pp.36-44
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• 2021

스크램제트 엔진 비행시험체의 굽어진 중앙동체 내부 유로에서 발생하는 충격파-경계층 상호작용에 대한 수치해석을 수행하였다. 수치해석에는 압축성 Raynolds Averaged Navier Stokes(RANS) 방정식에 난류모델 k-ω SST을 사용하였다. 대표적으로 노즐 윗 벽면의 박리기포, 오목한 충격파와 경계층의 상호작용, 모서리의 충격파-충격파 상호작용이 포착되었다. 해석 결과는 굽어진 내부 유로의 충격파-경계층 상호작용을 가시화하여 이해를 높이고 설계 유의점을 제시하였다.

• Journal of Yeungnam Medical Science
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• 제34권2호
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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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• 제57권5호
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• pp.465-469
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• 2004

저자들은 패혈증이나 혈액응고장애가 이상이 없는 소방이 형성된 흉막삼출 환자에서 비교적 안전한 것으로 알려진 urokinase의 주입 후에 발생한 혈흉과 이로 인한 hypovolemic shock을 경험하였기에 문헌 고찰과 함께 보고하는 바이다.

• 한국추진공학회지
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• 제24권3호
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• pp.31-40
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• 2020

다수의 충격파에 대한 구조와 거동특성은 노즐 출구 마하수가 1.75인 모델에 대하여 유한체적기법을 사용하여 수치해석적으로 조사하였다. 먼저 이미지를 기반으로 한 충격파 진동특성을 Matlab 프로그램을 사용하여 분석한 후 특정 위치에서 벽면 정압변화를 분석하였다. 또한 다수 충격파들의 진폭 및 주파수도 조사하였다. 충격파 위치들 사이의 상호상관은 첫번째 충격파와 두번째 충격파는 서로 관련이 있는 반면에 다른 충격파들은 진동특성에서 위상 지연을 나타내었다. 벽면 압력변동의 RMS값은 충격파 위치에서 최대이며 유동의 다른 부분에서는 낮은 OS 표준편차값을 나타내었다.

• Journal of Yeungnam Medical Science
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• 제31권1호
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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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• 제67권6호
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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.