• 한국정밀공학회지
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• 제23권7호
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• pp.101-107
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• 2006

Cold gas dynamic spray or cold spray is a novel manufacturing method for coatings. Cold spray is a high rate and direct material deposition process that utilizes the kinetic energy of particles sprayed at high velocity (300-1,200m/s). In this research, a technique to repair the damaged mold by cold spray deposition and mechanical machining was proposed. An aluminum 6061 mold with three-dimensional surface was fabricated, intentionally damaged and material-added by cold spray, and its original geometry was re-obtained successfully by Computer Numerical Control (CNC) machining. To investigate deformation of material caused by cold spray, deposition was conducted on thin aluminum plates ($100mm{\times}100mm{\times}3mm$). The average deformation of the plates was $205{\sim}290{\mu}m$ by Coordinate Measurement Machine (CMM). In addition, the cross section of deposited layer was analyzed by scanning electron microscopy (SEM). To compare variation of hardness, Vickers hardness was measured by micro-hardness tester.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제17권3호
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• pp.209-213
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• 1995

Various cutaneous as well as myocutaneous flaps have been designed for the reconstruction of tissue defects caused by the excision of oral cancer. Among these flaps, cervical island skin flap have been introduced by Farr et al and more have developed by Tashiro et al. This flap has many advantages. The flap minimizes donor size by use of cervical operation wound, flap size available is adequate for most oral defects and the procedure is relatively simple and time saving. However, this flap is not applicable in patients where there are large tissue defects and metastasis is suspected. We used this flap for it's rapid, simple, and effective, primary closure of oral defects after cancer ablation and we have found this flap very useful for the reconstruction of relatively small oral defects.

• Archives of Plastic Surgery
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• 제48권3호
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• pp.287-292
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• 2021

Background We report the efficacy of a dual-plane approach using a Dufourmentel skin flap with a purse-string suture of the de-epithelized dermis to manage pseudoaneurysm at the vascular access site for hemodialysis. Methods A retrospective analysis was conducted of 61 patients from 2013 to 2018 with pseudoaneurysms at the arteriovenous fistula or graft who were treated with rhomboid excision, vessel repair with a purse-string suture, and a full-thickness Dufourmentel skin flap. The success rate was defined as the probability of complete wound closure and intact vascular access patency without infection or other complications. Results The success rate was 93.4% at 6 months postoperatively. Complications included newly occurring pseudoaneurysms (n=2), wound dehiscence (n=1) and bleeding (n=1). There were no complications such as stenosis or thrombosis from the procedure. Conclusions A dual-plane approach using a Dufourmentel skin flap with a purse-string suture for vessel repair was shown to be a favorable option for managing stable, small (diameter <2 cm) pseudoaneurysms without infection, rapid expansion, or patency issues of the vascular access.

• 건축역사연구
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• 제30권4호
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• pp.79-90
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• 2021

Since its construction in the late 14th century, Hanyangdoseong had been carried out three major repairs and reconstructions during the 500 years of the Joseon Dynasty. In addition to the large-scale construction, small-scale construction continued until King Gojong era. In particular, in the 18th century, systematic construction management was implemented by the craftsmen and the military participated in the renovation of Hanyangdoseong in earnest, and the construction methods also developed rapidly. In the early 18th century, new construction techniques were attempted in various sections of the reconstruction work, and gradually became a common technology for repairing Hanyangdoseong in the late 18th century. The purpose of this study is to examine the characteristics and period of changes in the 18th century's construction technique, when the rapid development of Hanyangdoseong took place. To this end, the excavation results related to Hanyangdoseong, the remaining city wall, and the inscribed stones were used to identify and demonstrate the characteristics and change of the construction method.

• Structural Engineering and Mechanics
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• 제84권6호
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• pp.799-811
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• 2022

Adhesive bonding has seen rapid development in recent years, with emphasis to composite patch repairing processes of geometric defects in aeronautical structures. However, its use is still limited given its low resistance to climatic conditions and requirement of specialized labor to avoid fabrication induced defects, such as air bubbles, cracks, and cavities. This work aims to numerically analyze, by the finite element method, the failure behavior of a damaged plate, in the form of a bonding defect, and repaired by an adhesively bonded composite patch. The position and size of the defect were studied. The results of the numerical analysis clearly showed that the position of the defect in the adhesive layer has a large effect on the value of J-Integral. The reduction in the value of J-Integral is also related to the composite stacking sequence which, according to the mechanical properties of the ply, provides better load transfer from the plate to the repair piece through the adhesive. In addition, the increase in the applied load significantly affects the value of the J-Integral at the crack tip in the presence of a bonding defect, even for small dimensions, by reducing the load transfer.

• 교육녹색환경연구
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• 제17권2호
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• pp.38-47
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• 2018

본 연구는 안전성, 노후도, 경제성 등 시설 여건을 종합적으로 고려하여 개선이 필요한 중장기적인 사업물량 및 사업예산 규모를 추정할 수 있도록 하기 위해 국가수준의 시설개선 기준(수선주기)을 설정하여 체계적인 시설개선계획 수립을 통한 적정수준의 교육환경 확보에 기여할 수 있도록 하는 것을 주목적으로 한다. 적정 수선주기는 기본적으로 최근 2년간 교육청에서 실제 집행한 교육환경개선사업의 실적자료를 분석하여 직전 보수년도와 사업시행연도를 근거로 수선주기 기초자료를 산출하였다. 이를 근거로 17개 시도교육청 실무자를 대상으로 델파이 조사를 실시하여 시도교육청의 의견을 수렴하였으며 최종 적정 수선주기는 관련규정과 실적자료, 델파이조사 결과를 종합적으로 검토하여 설정하였다.

• Journal of Veterinary Science
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• 제21권6호
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• pp.90.1-90.11
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• 2020

Background: Mandibular fractures are common in camels, leading to considerable economic losses. This study explored methods of improving mandibular fractures repair, adjuvant with interdental wire, or bone plate fixation. Autologous bone marrow (BM) injection enhances osteogenesis and rapid healing. Objectives: To investigate the effect of autologous BM aspirate as an adjuvant treatment for repairing mandibular fractures in camels with interdental wire, or bone plate fixation. Methods: Thirty dromedary camels aged 5-8 years and of both sexes were randomly divided into 4 treatment groups: group 1 (n = 10) treated with stainless steel wire fixation and BM injection at the fracture line, group 2 (n = 10) treated with plate fixation and BM injection at the fracture line, group 3 (n = 5) treated with stainless steel bone wire fixation and placebo saline injection at the fracture line, and group 4 (n = 5) treated with plate fixation and placebo injection at the fracture line. The mandibular fractures were followed weekly for 12 weeks postoperatively to assess improvement and healing based on clinical evaluation, radiographic union scale, and bone turnover markers (i.e., bone alkaline phosphatase, osteocalcin, pyridinoline, and deoxypyridinoline). Results: Compared to other groups, elevated bone turnover markers in group 1 were demonstrated (p < 0.05) on the seventh postoperative day. Likewise, compared to other groups, both clinical findings and radiographic union scale significantly improved (p < 0.05) in group 1 on the 56th postoperative day. Conclusions: BM aspirate has a promising beneficial osteogenic effect on mandibular fracture repair in camels, most notably when combined with interdental wire fixation.

• 한국건축시공학회지
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• 제18권4호
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• pp.329-335
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• 2018

본 연구의 목적은 기존 콘크리트 건물의 단면확대 내진보강 기술에서 필요한 고유동 고접착성의 보강 모르타르 배합의 개발이다. 보강 모르타르의 목표성능(플로우 220mm 이상, 압축강도 30MPa, 접착강도 1MPa 이상)을 위해 물-결합재비, 잔골재-결합재비, 폴리머-결합재비, 증점제 사용 및 초속경시멘트의 혼입 등을 변수로 단계적으로 배합실험을 수행하였다. 모르타르의 접착강도는 기존 콘크리트의 다양한 면 처리 상태에 따라 평가하였다. 실험결과로부터 단면증설용 보강 모르타르의 배합을 위해 폴리머-결합재비는 10%, 초속경시멘트의 치환율은 5%가 추천될 수 있었는데, 이 배합은 초기 플로우 220 mm, 높은 초기강도 발현, 압축강도 35 MPa 그리고 접착강도 1.2 MPa 이상의 성능을 보였다.

• 한국임상수의학회지
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• 제29권1호
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• pp.8-11
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• 2012

본 조사는 골반골절을 수술적으로 교정한 31두 개에서의 결과를 분석한 것이다. 파행과 부중의 정도가 후지의 기능개선 평가에 이용되었다. 단순골절은 천장관절과 장골에서 발생하였으며, 골반골절은 관골절구의 골절을 포함하는 것과 포함하지 않는 경우가 있었다. 관골절구의 골절은 추가적인 대퇴골 머리 및 목 절제술 또는 관골절구 둘레 고정 만을 실시하였다. 단순골절은 복합골절에 비해 초기 회복시간과 완전한 회복시간 모두 짧았다. 관골절구를 포함하지 않는 골절에서는 포함한 골절에 비해 회복시간이 유의적으로 짧았다(p < 0.05). 또한 대퇴골 머리 및 목 절제술을 추가로 실시한 경우에서 실시하지 않은 것 보다 짧은 회복시간을 보였다. 소형견에서 관골절구의 골절 발생 시 대퇴골 머리 및 목 절제술을 이용한 수술적 교정은 대체 가능한 방법으로 생각된다.

• 한국구조물진단유지관리공학회 논문집
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• 제24권3호
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• pp.57-62
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• 2020

국내에 설치된 하수관거 중에서 20년을 초과한 콘크리트관의 연장은 66,334km로서 전체의 42.5%를 차지한다. 열화된 콘크리트 하수관거에서는 내부 하수의 유출로 인해 관로 주변의 동공을 확장시켜 땅꺼짐 등의 문제도 발생시키기 때문에 이에 대한 보수를 통한 유지관리가 필요한 실정이다. 본 연구에서는 초속경시멘트 및 분리저감제를 적용한 수중불분리성 모르타르를 하수관거 보수에 적용하기 위한 기초연구를 수행하였다. 배합조건에 따른 응결시험 결과 분리저감제 혼입에 따라 종결이 최대 172%정도 지연되는 것으로 나타났다. 수중분리도는 분리저감제 0.3% 이상 혼입시 pH 12 이하로 측정되었고, 현탁액량은 분리저감제 0.2% 이상 혼입시 50mg/l이하로 측정되어 국내 KCI-AD102 기준을 만족하였다. 기건조건과 수중조건에서 타설하였을 때의 강도비 평가 결과, 분리저감제 혼입시 80% 이상의 강도비를 나타내어 국내 KCI-AD102 기준을 만족하였다. 부착강도는 분리저감제 혼입시 기건조건보다 수중조건에서 타설하였을 때 높은 강도로 측정되었다. 내수성 검토는 분리저감제 혼입량에 따른 흡수율과 투수성으로 평가하였고, 각각 42.6%, 36.6%의 성능개선을 확인하였다.