• 한국구조물진단유지관리공학회 논문집
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• 제17권2호
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• pp.33-44
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• 2013

강바닥판의 구조상세에 대하여 많은 연구가 이루어지고 있으나, 대부분의 연구가 표준형의 U-rib를 대상으로 실시되었을 뿐, 강바닥판 건설초기의 개단면리브형식에 대한 연구는 미진한 것으로 조사되었다. 본 연구에서는 공용연수 31년된 개단면세로리브형식의 강바닥판 교량의 피로균열 발생 원인을 조사하기 위하여 실교통류하에서의 계측 데이터를 통하여 대상구조상세의 거동 특성을 분석하였다. 또한 상세구조해석을 통하여 대상교량을 통과하는 대표트럭하중을 추정하고, 상세영향면해석을 이용하여 대상구조상세의 응력 및 변형특성을 분석하였다. 이들 분석에 기초하여 피로균열이 발생된 대상구조상세의 보강방안을 제시하고, 이에 대한 타당성을 검증하였다. 연구결과, 개단면리브에서의 피로균열의 발생원인은 개단면부에서의 전단변형에 의한 응력증가 및 차량의 이동에 따른 교번응력의 발생에 기인하는 것으로 조사되었으며, 국부구조상세에 대한 피로설계에서는 구조상세의 거동특성이 충분히 반영된 상세해석에 근거한 설계를 실시하는 것이 중요하다는 것을 알 수 있었다.

• 한국강구조학회 논문집
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• 제17권5호통권78호
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• pp.593-604
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• 2005

본 논문에서는 개단면 리브를 갖는 보강판에 대하여 직교이방성 강성비를 매개변수로 하여, 집중하중이 작용하는 경우 발생하는 보강판의 국부 처짐 및 국부 모멘트에 대한 연구를 수행하였다. 보강판의 국부 거동을 파악하기 위하여 리브 사이에 위치한 판의 중앙점에 하중이 작용하는 경우를 고려하였으며, 전체적인 거동을 산정하기 위하여, 판의 중앙에 위치한 리브 위에 하중이 작용하는 경우를 해석하였다. 여러 가지 보강판에 대한 국부 거동을 분석한 결과, 국부 모멘트의 증가 비율은 리브 간격과 상관없이 리브 크기에 따라 일정함을 알 수 있었으며, 또한, 보강판의 전체 처짐에 대한 국부 처짐의 비율은 리브 간격과 강성비의 함수로 표현할 수 있음을 알 수 있었다. 이러한 관계식을 예제에 적용한 결과, 실제 국부 처짐이 발생하는 경우와 상당한 정확도를 나타내었으며, 또한 직교이방성 판 해석에 적용한 결과, 상당한 정확도의 증가를 나타내었다. 따라서, 본 연구에서 제안한 함수식을 이용하면, 개단면 리브를 갖는 보강판의 전체 거동으로부터 간편하게 국부 거동 결과를 예측할 수 있을 것으로 판단된다.

• 대한기계학회논문집B
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• 제41권2호
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• pp.109-115
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• 2017

전산유체해석(CFD) 기법을 이용하여 음극 지지체형 고체산화물 연료전지(SOFC)에 대한 수치해석을 수행하였다. 평판형 구조의 SOFC 에서 가스채널과 리브폭 변화에 따른 성능과 온도균일성에 관한 연구가 이루어졌다. 전산해석 툴로서는 공개소스 전산유체해석 툴박스인 OpenFOAM 을 이용하였다. 수치해석결과, 산소고갈이 일어나지 않는 범위 내에서 가스채널과 리브폭의 증가는 성능과 온도 균일성에 크게 영향을 미치지 않음을 알 수 있었다. 하지만 넓은 리브폭의 사용과 고전류밀도에서의 작동은 산소고갈로 인한 성능저하의 가능성이 있음을 확인하였다.

• Journal of Chest Surgery
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• 제56권2호
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• pp.120-125
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• 2023

Background: Multiple rib fractures are common in blunt chest trauma. Until recently, most surgical rib fixations for multiple rib fractures were performed via open thoracotomy. However, due to the invasive nature of tissue dissection and the resulting large wound, an alternative endoscopic approach has emerged that minimizes the postoperative complications caused by the manipulation of injured tissue and lung during an open thoracotomy. Methods: Our study concentrated on patients with multiple rib fractures who underwent surgical stabilization of rib fractures (SSRF) between June 2018 and May 2020. We found 27 patients who underwent SSRF using video-assisted thoracoscopic surgery. The study design was a retrospective review of the patients' charts and surgical records. Results: No intraoperative events or procedure-related deaths occurred. Implant-related irritation occurred in 4 patients, and 1 death resulted from concomitant trauma. The average hospital stay was 30.2±20.1 days, and ventilators were used for 12 of the 22 patients admitted to the intensive care unit. None of the patients experienced major pulmonary complications such as pneumonia or acute respiratory distress syndrome. Conclusion: Minimally invasive rib stabilization surgery with the assistance of a thoracoscope is expected to become more widely used in patients with multiple rib fractures. This method will also assist patients in a quick recovery.

• 한국수자원학회논문집
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• 제46권9호
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• pp.947-956
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• 2013

급경사 산지하천 수충부의 호안은 대부분 콘크리트 옹벽으로 되어있다. 표면이 매끄러운 콘크리트 옹벽호안은 유속을 더 강화시키기 때문에 수충부 홍수피해의 원인이 되기도 한다. 본 연구에서는 개수로의 한 측벽에 설치한 정사각형 단면의 세로돌출줄눈이 흐름저항에 미치는 영향을 파악하기 위해 수리실험을 수행하였다. 돌출줄눈의 설치간격은 무차원 돌출줄눈 간격 ${\lambda}_{nv}$를 기준으로 조도유형 d형과 k형을 포함하도록 설계하였다. 흐름의 Froude 수는0.81~1.12의 범위였다. 흐름저항은 돌출줄눈의 설치간격과 유량에 좌우되었다. ${\lambda}_{nv}$가 9일 때 흐름저항이 가장 큰 것으로 나타났다. 세로돌출줄눈은 유량이 증가하면 d형 조도에서는 흐름저항을 감소시켰으나 k형 조도에서는 흐름저항을 증가시켰다. 흐름저항의 증가폭은 ${\lambda}_{nv}$이 9~12의 범위에서 상대적으로 더 크게 나타났다. 세로돌출줄눈에 의한 흐름저항은 대부분 형상저항에 의한 것이며 그 등가조도높이는 수심규모로 발생할 수 있고 흐름저항에 미치는 영향이 매우 크다. 측벽의 세로돌출줄눈은 흐름저항을 증가시키고 최대유속의 발생위치를 수로의 횡단면 중앙방향으로 이동시키는 수단으로 사용될 수 있을 것이다.

• Journal of Chest Surgery
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• 제12권4호
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• pp.411-417
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• 1979

During the period of 4 years from August 1, 1975 to August 1, 1979, authors have experienced 100 cases of multiple rib fractures by nonpenetrating injury at Department of Thoracic Surgery, Paik Foundation Hospital in Seoul, Korea. 1. The ratio of male to female patients with multiple rib fracture was 2.6:1 with male predominance and 84% of the total cases were between 20 and 50 years of age. 2. The most common cause of multiple rib fracture was traffic accident and falls accounted for the next largest group. 3. The most common site of rib fracture was 4th rib to 7th rib level on both hemithorax [52%]. 4. Associated injuries were cerebral contusion in 26%, clavicular fracture in 22%, long bone fracture in 22%, pelvic bone fracture in 10%, and scapular fracture in 8%. 5. Early complications and/or result of the multiple rib fractures were lung contusion in 23 cases, subcutaneous emphysema in 21 cases, hemothorax in 21 cases, hemopneumothorax in 6 cases, and flail chest in 12 cases. 6. The flail chests were managed by strapping the chest with adhesive plaster, external traction of flail segment with towel clip, ventilatory assistance for marginal clinical indications, and in cases of complicated with intrathoracic hemorrhage, wire fixation of flail segment through open thoraco-tomy. 7. The principles of therapy for hemothorax and/or pneumothorax were rapid reexpansion of the lungs by thoracentesis [11%] and closed thoracostomy [22%], but open thoracotomy had to be done on 3 cases because of massive bleeding or intrapleural hematoma and diaphragmatic rupture. 8. The over all mortality was 4% [4 among 100 cases] and the cause of all deaths was head injury.

• Steel and Composite Structures
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• 제42권6호
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• pp.843-853
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• 2022

The fatigue behavior of welded open rib-to crossbeam joints (ORCJ) in orthotropic bridge structures is investigated using a traction structural stress method. The fatigue behaviors of welded open rib-to crossbeam joints have been a subject of study for decades for ensuring operational safety and future design improvement. A mesh-insensitive combination of traction structural stresses in ORCJ was obtained considering the effect of in-plane shear stress and validated by fatigue test results. The proposed method is advantageous for predicting fatigue cracks that initiate from the crossbeam cutout and propagate along the crossbeam. The investigations carried out with the proposed approach reveal that the normal structural stress decreases with the propagation of fatigue cracks, while the ratio of shear stress to normal stress increases. The effect of shear structural stress is significant for the analysis of fatigue behavior of ORCJ in multiaxial stress states.

• Journal of Trauma and Injury
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• 제30권4호
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• pp.179-185
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• 2017

Purpose: Rib fracture is the most common complication of blunt thoracic trauma. We investigated the effect of rib fracture on pulmonary function in the conservatively treated patients. Methods: From January 2000 to February 2017, we reviewed the records of 72 patients with rib fracture and pulmonary function tests were performed. According to the number of rib fractures, patients were classified into two groups: less than six fractured ribs (group A) and more than six fractured ribs (group B). The groups were compared concerning demographics, underlying diseases, associated thoracic injuries, surgery, mechanical ventilator times, days spent in the intensive care unit and pulmonary function test. Results: There were no statistically significant differences in the demographic data between the two groups. Mean hospitalization was 13.5 days in group A and 27.0 days in group B (p<0.001). There was no statistically significant difference between the two groups in the pulmonary function test. Conclusions: We conclude that pulmonary function is restored by conservative treatment in patients with rib fractures even if the number of rib fractures increases. In patients with multiple rib fractures, studies comparing open rib fixation and conservative treatment of long term pulmonary function are required.

• Journal of Trauma and Injury
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• 제30권2호
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• pp.63-65
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• 2017

Standard open procedures for resection of the first rib in thoracic outlet syndrome can prove to be quite difficult with extensive incisions. A minimal invasive procedure can also be painstaking, but provides an attractive alternative to the more radical open procedures. We report the details of the technique with direct video footage of the procedure performed in a 41-year-old man with thoracic outlet syndrome done entirely by thoracoscopic methods.

• Journal of Chest Surgery
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• 제17권1호
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• pp.110-117
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• 1984

A clinical evaluation was performed on 76 cases of chest injury experienced at department of Chest Surgery, Capital Armed Forces General Hospital during the past 3 years period from January 1981 to August 1983. 1.The most common cause of the chest trauma was gun shot by which 26 cases were injured among 44 cases [57.9%] of penetrating injury. Remaining 32 cases [42.1%] were injured by non-penetrating blunt trauma. 2.Hemopneumothorax was observed in 60 cases [78.9%], those were caused by both penetrating [65%] and non-penetrating [35%] injuries. 3.Rib fracture was found in 58.7% of total cases and with rib fracture, clavicle fracture was combined at 19.6% and sternal fracture, at 8.7%. 4.Most common symptoms were chest pain and dyspnea, and most common signs were breath sound diminution and subcutaneous emphysema. 5.Common site of rib fracture was from 4th rib to 8th rib [69.4%]. 6.In 58 cases [76.3%], patients were treated with operation including open thoracotomy [25 cases]. 7.Overall mortality was 5.3%[4 cases] and causes of death were septic shock and respiratory failure.