• 항공우주시스템공학회지
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• 제17권4호
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• pp.118-125
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• 2023

풍동시험은 유도무기체계 개발에 있어서 필수적인 과정 중 하나이며, 시험 조건 및 용도에 따라 다양한 풍동설비가 존재한다. Ludwieg Tube는 극초음속 유도무기 체계개발에서 매우 유용하며, 고 받음각 시험 및 풍동시험 결과의 반복성, 일관성이 필요한 가운데 풍동시험 설비의 능력보강이 필요하였다. 본 논문에서는 국방과학연구소 Ludwieg Tube가 가졌던 문제점과 노즐, 진공탱크 및 모형지지부 성능개량을 통한 문제해결 방안을 제시하고 풍동시험 간 압력 측정 결과를 바탕으로 해결 방안을 증명하였다.

• 한국진공학회지
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• 제1권1호
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• pp.16-23
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• 1992

Conductance calculation is essential in designing a vacuum system. Since mathematical solution is nearly impossible except for a few simple cases, it has been so usual to calculate the conductance for a series connection of components using an approximate formula by Oatley. However, Oatley's formula has a fundamental flaw of totally neglecting the effect of gas beaming. In this study, a new technique is suggested for calculating the conductance with the same accuracy as the Monte Carlo method but with much less computing time, and applied to a system of tube connections in series. The effects of gas beaming in the calculation of conductance is analyzed quantitatively by comparing the conductance calculated by this method with those from Oatley's formula.

• Journal of Chest Surgery
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• 제56권5호
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• pp.362-366
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• 2023

The stomach has become the most commonly used site for grafts to replace the esophagus in esophageal cancer surgery because of its good blood supply and ability to enable single-reconstruction anastomosis. However, anastomotic failure is a serious complication after esophageal cancer surgery. Unlike anastomotic leakage due to local ischemia, gastric tube necrosis is a life-threatening condition with a high mortality rate. Gastric tube necrosis involves extensive ischemia due to a decreased blood supply, and an urgent operation is mandatory in most cases. Endoscopic vacuum therapy (EVT) has been used for anastomotic leakage after esophageal surgery. In recent years, it has been successfully used for more extensive disease, including large esophageal perforation as an indication for reoperation. Hence, we report a case of extensive gastric tube necrosis treated by EVT after an Ivor Lewis operation.

• Nuclear Engineering and Technology
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• 제38권5호
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• pp.455-458
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• 2006

The HANARO reactor has a vertical hole for a cold neutron source (CNS) in the heavy-water reflector tank, i.e., the CNS hole, which was considerably deformed during its welding to the horizontal cold neutron (CN) beam tube. This paper presents an investigation of the form of the CNS hole for the optimal design of the a vacuum chamber for the CNS. In addition, the installation method of the vacuum chamber into the CNS hole for minimizing the water thickness between the vacuum chamber and the nose of the CN beam tube is proposed.

• Journal of Chest Surgery
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• 제53권4호
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• pp.205-210
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• 2020

Esophageal anastomotic leak is the most common and serious complication following esophagectomy. However, the standard treatment for anastomotic leaks remains unclear. Recently, endoscopic vacuum therapy has become an important non-surgical alternative treatment method for patients with esophageal anastomotic leak. This treatment involves the endoscopic placement of a sponge connected to a nasogastric tube into the defect cavity or lumen. Subsequently, continuous negative pressure is delivered to the cavity through the tube. Several studies have reported a treatment success rate of 80% to 100%. In this study, we review the mechanism of action, the method of performing the procedure, its safety and efficacy, and prognostic factors for failure of endoscopic vacuum therapy in the management of patients with anastomotic leak, and on this basis attempted to confirm the possibility of establishing a standardized treatment protocol using endoscopic vacuum therapy.

• 조명전기설비학회논문지
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• 제19권5호
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• pp.60-67
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• 2005

본 논문에서는 진공방전관을 이용한 고농도 중첩방전형 오존발생기를 설계$\cdot$제작하였다. 3개의 전극(중심전극, 내부전극 및 외부전극)과 1개의 방전간극(내부전극과 외부전극 사이의 방전간극)으로 구성된 중첩방전형 오존발생기는 진공방전관내에 장착한 중심전극과 내부전극에 $180{[^\circ]}$의 위상차를 가진 2개의 교류고전압을 인가하고 외부전극을 공통접지함으로써 중심전극과 외부전극사이에서 발생되는 무성방전과 내부전극과 외부전극사이에서 발생되는 무성방전이 방전간극에서 중첩되는 구조이다. 이때 방전관의 진공도, 방전전력 및 산소원료가스 유량 변화에 따른 방전특성과 오존생성특성을 연구검토한 결과 최대 8840[ppm]의 고농도 오존을 얻을 수 있었다.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1511-1517
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• 2012

진공유리 배기공정을 위해 진공챔버나 진공튜브를 이용하는데 챔버 혹은 튜브 내부 전체를 진공으로 만들기 위한 시간과 경비가 과도하게 요구된다. 이러한 문제점을 해결하기 위해 상압에서 진공배기 및 초음파 접합이 동시에 가능한 복합기를 개발하고자 하였는데, 이 경우 진동자인 피에조 온도가 과도하게 상승하여 복합기의 냉각을 최적화할 필요성이 대두되었다. 따라서, 본 연구에서는 수치해석 및 실험을 통해 자연대류 및 강제대류 냉각방식의 효과를 규명하였고 이를 통해 진공 배기 및 초음파 접합 복합기의 냉각 성능을 최적화하였다.

• 대한간호학회지
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• 제42권3호
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• pp.443-451
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• 2012

Purpose: This study was done to compare the rates of hemolysis and repeated sampling in blood samples obtained by a syringe needle versus a vacuum tube needle. Methods: A randomized, prospective study was used to evaluate the differences between the two blood sampling methods. The study group consisted of patients seen in the emergency department (ED) for blood sampling to determine electrolyte level. ED patients were randomly assigned to either the syringe group or the vacuum tube group. All blood samples were collected by experienced ED nurses and hemolysis was determined by experienced laboratory technologists. Data were analyzed using Fisher's exact test and binary logistic regression. Results: One hundred forty-five valid samples were collected (74 in the syringe group versus 71 in the vacuum tube group). 5 of 74 (6.8%) blood samples in the syringe group and 8 of 71 (11.3%) in the vacuum tube group hemolyzed. Repeated blood sampling occurred for 2 of 74 (2.7%) and 3 of 71 (4.2%) in each group respectively. There were no significant differences in rates of hemolysis and repeated sampling between two groups (B=1.97, p=.204; B=2.36, p=.345). Conclusion: Venipuncture with syringe needles can be recommended for ED nurses to obtain blood samples.

• Journal of Chest Surgery
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• 제51권1호
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• pp.76-80
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• 2018

Early diagnosis followed by primary repair is the best treatment for spontaneous esophageal perforation. However, the appropriate management of esophageal leakage after surgical repair is still controversial. Recently, the successful adaptation of vacuum-assisted closure therapy, which is well established for the treatment of chronic surface wounds, has been demonstrated for esophageal perforation or leakage. Conservative treatment methods require long-term fasting with total parenteral nutrition or enteral feeding through invasive procedures, such as percutaneous endoscopic gastrostomy or a feeding jejunostomy. We report 2 cases of esophageal leakage after primary repair treated by endoscopic vacuum therapy with continuous enteral feeding using a Sengstaken-Blakemore tube.

• 한국진공학회지
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• 제22권2호
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• pp.45-54
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• 2013

맥동관형 크라이오펌프 개발 사업 2단계를 맞아 우성진공(유)을 중심으로 상용화 시제품 개발이 성공적으로 끝나가고 있다. 최종 크라이오펌프 개발품은 흡기구 직경(내경) 16.5 (14) 인치에 질소 배기속도 3,600 L/s 이상을 목표로 하고 있다. 개발품의 성능확인을 위해 우선 몬테카를로 계산을 통해 배기속도를 예측하고 구조설계를 최적화했으며 이를 바탕으로 가공 조립된 크라이오펌프 시제품의 성능을 표준화된 장치에서 표준화된 절차를 통해 평가하여 설계 목표값과 비교했다. 시제품의 질소 배기속도는 4,600 L/s로 측정되어 설계값과 잘 일치하였으며 개발목표를 훨씬 상회하였다.