• Journal of Chest Surgery
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• 제45권4호
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• pp.230-235
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• 2012

Background: Although patients with a ruptured abdominal aortic aneurysm (RAAA) often reach the hospital alive, the perioperative mortality is still very high. We retrospectively reviewed thirty patients who underwent repair of RAAA to identify the factors affecting postoperative mortality in a single hospital. Materials and Methods: Between September 2007 and May 2011, thirty patients with RAAA underwent emergent surgery (n=27) or endovascular aneurysm repair (n=3). Their medical records were retrospectively reviewed regarding three categories: 1) preoperative patient status: age, gender, vital signs, serum creatinine, blood urea nitrogen, hematocrit, and hemoglobin level: 2) aneurysmal status: size, type, and rupture status; and 3) operative factors: interval time to operating room, operative duration, and amount of perioperative transfusion. Results: The 30-day postoperative mortality rate was 13.3% (4/30); later mortality was 3.3% (1/30). On multivariate analysis, the initial diastolic blood pressure (BP), interval time to operating room and amount of preoperative packed cell transfusion were statistically significantly linked with postoperative mortality (p<0.05). Conclusion: In this study, preoperative diastolic BP, preoperative packed cell transfusion amount and interval time between arrival and entry to operating room were significantly associated with postoperative mortality. It is important to prevent hemorrhage as quickly as possible.

• 한국분말재료학회지
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• 제25권4호
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• pp.302-308
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• 2018

A lean alloy is defined as a low alloy steel that minimizes the content of the alloying elements, while maintaining the characteristics of the sintered alloy. The purpose of this study is to determine the change in microstructure and mechanical properties due to the addition of silicon or tin in Fe-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P alloys. Silicon- or tin-added F-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P master alloys were compacted at 700 MPa and subsequently sintered under a $H_2-N_2$ atmosphere at $1120^{\circ}C$. The sintered density of three alloy systems decreases under the same compacting pressure due to dimensional expansion with increasing Si content. As the diffusion rate in the Fe-P-Mo system is higher than that in the Fe-P-Mn system, the decrease in the sintered density is the largest in the Fe-P-Mn system. The sintered density of Sn added alloys does not change with the increasing Sn content due to the effect of non-dimensional changes. However, the effect of Si addition on the transverse rupture strengthening enhancement is stronger than that of Sn addition in these lean alloys.

• 대한기계학회논문집A
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• 제30권9호
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• pp.1034-1040
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• 2006

Due to the need of increasing thermal efficiency, supercritical pressure and temperature have been utilized in power plants. It is well known that 9Cr1Mo steel is suitable fer use in power plants operating at supercritical conditions. Therefore, to ensure the safety and the soundness of the power plant, creep characterization of the steel is important. In this study, the creep characterization of the gCr1Mo steel using small punch creep(SP-Creep) test has been described. The applied load and the central displacement of the specimen in SP-Creep test have been converted to bearing stress and strain of uc, respectively. The converted SP-Creep curves clearly showed the typical three-stage behavior of creep. The steady-state creep rate and the rupture time of the steel logarithmically changed with the bearing stress and satisfied the Power law relationship. Furthermore, the Larson-Miller parameter of the SP-Creep test agreed with that of the tensile creep test. From the comparison with low Cr-Mo steels, the creep characteristics of 9Cr1Mo steel proved to be superior. Thus, it can be confirmed that the 9Cr1Mo steel is suitable for supercritical power plant.

• Nuclear Engineering and Technology
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• 제27권4호
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• pp.483-490
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• 1995

PKL III A 4.4 실험은 "증기발생기 세관파열사고 후 소외전원 가용의 조건 하에서 발전소가 비상냉각수 주입없이 수작동에 의해 제어될 수 있음을 확인하는 것이다. 실험 모사에 따른 NLOOP Code의 제한이나 능력의 검증을 위해, 실험에서 얻어진 PKL 설비의 거동은 NLOOP의 결과와 상호 비교되었다. NLOOP 코드는 한국원자력연구소와 독일 SIEMENS/KWU사에 의해 Westinghouse 형 발전소의 과도현상 해석용으로 개발되었으며, PKL III 설비모사를 위해 적절히 수정되었다. 자연대류에 의한RCS Loop의 냉각수 유량과 격리된 RCS Loop에서의 자연대류 중단현상을 특별히 주의깊게 연구하였다. 실험과 계산 결과의 비교는 NLOOP 코드의 의사능가 문제점들을 보여준다.보여준다.

• 한국식품조리과학회지
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• 제19권4호
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• pp.511-520
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• 2003

This study was carried out to determine the effects of various contents of kiwifruit contents on the quality characteristics of mixed polysaccharide gels made from $\kappa$-carrageenan and locust bean gum. The color value, gelling temperature, melting temperature, break down rate, syneresis, rupture properties, TPA properties and sensory properties of mixed polysaccharide gels with various contents of kiwifruit contents were measured. As the kiwifruit contents was increased, the lightness (L), yellowness (b) and greenness (-a) of the mixed polysaccharide gels increased. There were no differences in the color values of gels during storage. As the kiwifruit content was increased, the gelling and melting temperatures of the mixed polysaccharide gels also increased. The mixed polysaccharide gels with high kiwifruit contents were difficult to melt, and it seemed that the addition of kiwifruit to the mixed polysaccharide gels could improve the thennal stability of the gels. The syneresis of the gel increased with increasing storage time, whereas the addition of kiwifruit to the gel resulted in suppression of syneresis. With regard to the rupture properties, stress, energy and strain, they were all decreased with increasing kiwifruit contents. The TPA properties, adhesiveness, hardness and chewiness increased and cohesiveness decreased with increasing kiwifruit contents. The results showed that the gel became tough and adhesive, and could be easily broken under small deformation, with increasing kiwifruit contents. The sensory evaluation showed that the green color, aroma, sweetness and sourness increased with increasing kiwifruit contents. The texture, adhesiveness, springiness and cohesiveness decreased, and brittleness and hardness increased, with increasing kiwifruit contents. The overall acceptability of the gel with 30% kiwifruit content was the highest. Thus, mixed polysaccharide gels made from kiwifruits could be useful, as the addition of kiwifruit to a mixed polysaccharide gel results in a good aroma, taste and stability, despite a lowering of the textural properties.

• 한국가스학회지
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• 제22권6호
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• pp.28-33
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• 2018

최근 들어 정부는 도시가스 미공급지역 해소 및 소규모 공급지역의 경제성 확보를 위해 준저압 공급을 확대하고 있다. 주로 중앙 저장 탱크에서 매설 배관으로 각 세대에 공급하고 있는데 타공사에 의한 매설 배관의 파손 시 가스의 누출을 차단할 방법으로 배관 파손에 의한 과류를 차단할 수 있는 밸브의 필요성이 대두되고 있다. 이 연구를 위해 System CFD Code인 Flownex를 이용하였으며 실제 과류차단밸브에 해당되는 Component를 개발 완료하였다. 본 연구를 진행하면서 Flownex의 정확도를 검증하기 위해 실험값과 비교 하였으며 2% 내외의 오차율을 확인하였고 본 연구를 위해 사용이 가능한 것으로 판단되었다. 본 연구에서는 마을 단위의 LPG 공급 배관망을 선정하여 Modeling을 하였으며 주배관에서 세대로 인입되는 가지관의 이음 부위에 임으로 과류차단밸브 Component를 설치하였다. 주 배관에서 세대까지 가장 긴 배관을 선택하여 세대 인입 직전에 배관을 임으로 파손시켜 과류가 발생하도록 시나리오를 정하였다. 배관이 파손됨에 따라 과류가 발생하게 되고 과류차단밸브가 작동하게 되는데 이 때 과류차단 밸브의 작동이 타 배관에 미치는 영향 및 오작동 유무를 분석하였다.

• Journal of Trauma and Injury
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• 제34권2호
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• pp.81-86
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• 2021

Purpose: This study investigated the clinical outcomes of trauma patients with blunt thoracic aortic injuries at a single institution. Methods: During the study period, 9,501 patients with traumatic aortic injuries presented to Trauma Center of Gil Medical Center. Among them, 1,594 patients had severe trauma, with an Injury Severity Score (ISS) of >15. Demographics, physiological data, injury mechanism, hemodynamic parameters associated with the thoracic injury according to chest computed tomography (CT) findings, the timing of the intervention, and clinical outcomes were reviewed. Results: Twenty-eight patients had blunt aortic injuries (75% male, mean age, 45.9±16.3 years). The majority (82.1%, n=23/28) of these patients were involved in traffic accidents. The median ISS was 35.0 (interquartile range 21.0-41.0). The injuries were found in the ascending aorta (n=1, 3.6%) aortic arch (n=8, 28.6%) aortic isthmus (n=18, 64.3%), and descending aorta (n=1, 3.6%). The severity of aortic injuries on chest CT was categorized as intramural hematoma (n=1, 3.6%), dissection (n=3, 10.7%), transection (n=9, 32.2%), pseudoaneurysm (n=12, 42.8%), and rupture (n=3, 10.7%). Endovascular repair was performed in 71.4% of patients (45% within 24 hours), and two patients received surgical management. The mortality rate was 25% (n=7). Conclusions: Traumatic thoracic aortic injuries are life-threatening. In our experience, however, if there is no rupture and extravasation from an aortic injury, resuscitation and stabilization of vital signs are more important than an intervention for an aortic injury in patients with multiple traumas. Further study is required to optimize the timing of the intervention and explore management strategies for blunt thoracic aortic injuries in severe trauma patients needing resuscitation.

• 한국약용작물학회지
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• 제7권1호
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• pp.16-21
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• 1999

파종부터 유묘출현까지 2년이 소요되는 둥굴레의 종자번식에서 육묘기간을 단축하기 위하여는 우선적으로 적절한 상배축 휴면타파 방법이 설정되어야 할 것이다. 본 시험은 둥굴레의 상배축 휴면타파 방법 을 설정 하고자 $GA_3\;1.0\;mM$을 2일 간격으로 2회 또는 4회 (4일 : 8일) 관주하거나, 4, 6, 8, 12주간 $3^{\circ}C$의 저온처리를 가한 후 유묘 출현과 생장에 관련된 형질을 조사하였던 바 그 결과를 요약하면 다음과 같다. $GA_{3}$ 처리시 자엽(子葉) 파열수(破裂數)는 처리 직후에는 4일 보다 8일 처리에서 높았으나 시간이 경과할수록 처리효과가 소멸된 반면, 상배축 신장이 이루어지지 않아 출현 유묘가 전혀 없었다. 따라서 $GA_3$을 이용한 둥굴레의 상배축 휴면타파는 실험실에서 소규모로 행할 경우는 가능하다고 할지라도 상토를 이용한 다량육묘에서는 적용이 불가능한 것으로 나타났다. 이러한 원인은 $GA_3$ 용액의 관주처리시 자엽초는 파열되나 상배축이 여러 겸의 자엽초로 싸여져 있기 때문에 $GA_3$ 용액에 노출되지 않은 결과로 해석된다. 한편 자엽초 파열과 상배축 신장이 원활히 이루어지는 저온처리는 다량육묘에 이용이 가능하다고 할 수 있다. 그러나 입묘 정도는 저온처리 기간에 의하여 영향을 받는 것으로 나타났는데 적어도 6주의 저온처리가 가하여져야 할 것으로 분석되었다.

• 한국화재소방학회논문지
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• 제13권4호
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• pp.7-12
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• 1999

석유 화학플랜트에서 다량 부산되는 가연성 고체인 EVA(ethyl vinyl acetate) 분진의 열적특성 및 산화제와의 혼촉 위험성을 조사하였다. 시차주사열량계(DSC, Differential Scanning calorimeter) 및 열중량 분석기(TGA, Thermogavimetric Analysis)를 이용하여 온도에 따른 발열개시온도 및 중량감소를 조사하였고, EVA 분진의 위험성을 살펴보고자 몇 가지 대표적인 산화제와 혼합하여 무게비에 따른 압력용기 내에서의 혼촉 위험성을 조사하였다. DSC 분석 결과 EVA 분진의 열분해에 따른 발열 peak가 220~$250^{\circ}$ 부근에서 나타나고 있으며, TGA 분석결과 EVA 분진의 분해온도는 250~$500^{\circ}$ 범위이다. 압력 용기 시험에 의한 산화제와 EVA 분진의 혼촉 위험성은 오리피스 직경이 감소할수록 증가하며, 승온속도가 증가할수록 증가한다. 또한 승온속도가 느린 경우에는 시료의 분해온도와 산화제의 분해온도가 비슷한 경우 혼촉 위험성이 크게 나타났으며, 승온속도가 빠른 경우에는 시료 및 산화제의 분해온도보다는 분자 내에 산소의 함유량이 높은 산화제가 혼촉 위험성이 크게 나타났다.

• Journal of Advanced Marine Engineering and Technology
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• 제27권6호
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• pp.797-805
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• 2003

This paper describes experimental investigations of helium-air exchange flow through single opening and partitioned opening. Such exchange flows may occur following rupture accident of stand pipe in high temperature gas cooled reactor. A test vessel with a small opening on top of test cylinder is used for experiments. An estimation method of mass increment is developed and applied to measure the exchange flow rate. A technique of flow visualization by Mach-Zehnder interferometer is provided to recognize the exchange flows. Flow measurements are made with the opening, for partition ratios H_p/H$_1$$ in the range 0 to 1. where H_p$ and H$_1$ are partition length and height of the opening. respectively. In the case of H_p/H$_1$$ of 0, flow passages of upward flow of the helium and downward flow of the air within the opening are unseparated (bidirectional), and the two flows interfere within the opening. The unseparated flow increases strength of flow resistance and therefore, the exchange flow rate is minimum through range of the partition ratios. Two flow zones, i.e., separated (unidirectional) flow zone and unseparated (bidirectional) flow zone, exist with increasing the partition length. The exchange flow rate increases with increasing the separated flow zone. It is found that a maximum exchange flow rate exists at H_p/H$_1$$ of 1. As a result of comparison of the exchange flow rates by changing the partition ratio, the fluids Interference in the unseparated zone is found to be an important factor on the helium-air exchange flow rate.