• 한국공간구조학회논문집
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• 제23권4호
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• pp.71-79
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• 2023

In this study, a prefabricated buckling brace (PF-BRB) was proposed, and a test specimen was manufactured based on the design formula for the initial shape and structural performance tests were performed. As a result of the experiment, all standard performance requirements presented by KDS 41 17 00 and MOE 2021 were satisfied before and after replacement of the reinforcement module, and no fracture of the joint module occurred. As a result of the incremental load test, the physical properties showed a significant difference in the stiffness ratio after yielding under the compressive load of the envelope according to the experimental results. It is judged necessary to further analyze the physical properties according to the experimental results through finite element analysis in the future.

• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.535-543
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• 2017

목구조물 기둥-보 접합물로는 슬릿 가공된 부재에 강판을 삽입한 형상이 통용되고 있다. 본 연구에서는 접합부가 접착된 강절형 문형라멘프레임 및 강판 대용인 목질접합물을 제작하여 절반은 기둥부재에 일체화하고 나머지 절반은 보부재와 핀으로 접합한 반강절형 문형라멘프레임을 제작하였다. 목질 문형라멘프레임들은 강판삽입형 접합부 문형라멘프레임과 수평내력성능을 비교 분석하였다. 수평내력성능은 완전탄소성모델 분석과 구간별 강성변화율 및 단기허용전단내력으로 평가하였다. 실험결과, 강절형 문형라멘프레임의 최대내력이 강판삽입형 접합부 문형라멘프레임 보다 낮게 측정되어 항복 내력은 0.58, 종국내력은 0.48로 산출되었으나, 초기강성과 소성률은 각각 1.35, 1.1 향상된 값이 측정되었다. 반강절형 문형라멘프레임의 완전탄소성모델 분석 결과 최대내력은 강절형 문형라멘프레임보다 낮았으나 파괴 후 인성이 우수하여 종국내력은 1.05~1.07 높은 값이 산출되었다. 강판삽입형 문형라멘프레임은 반복 시험이 진행됨에 따라 강성이 급격히 감소한 반면 접합부가 목질로된 문형라멘프레임들의 강성은 서서히 감소되었다.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5947-5955
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• 2013

본 연구에서는 급속시공이 가능한 모듈러 도로포장 시스템에서 포장체 모듈 사이의 조인트에서 발생하는 축방향 변형량을 평가하고, 시멘트 페이스트, 에폭시, 폴리우레탄을 매트릭스로 하는 2성상 복합재료에 대하여 조인트 연결재료로서의 적용가능성을 검토하였다. 포장체 모듈 하부에 받침이 있는 경우와 노반에 직접 접촉하는 경우에 대해 FEM해석을 실시하여 발생 변형량을 평가하였다. 변형 유발 요인으로 자중 및 활하중, 온도변화 및 건조수축을 고려하였으며, 그 중 온도변화에 의한 영향이 가장 큰 것으로 나타났다. 2성상 복합체의 변형성능 예측은 수정 전단지연 모델을 이용하여 수행하였다. 모래 혼입 부피비율에 따른 복합체의 탄성계수와 최대 인장변형률 변화를 검토한 결과, 15~20 mm의 조인트 폭에 대해, 폴리우레탄을 사용할 경우 모래를 20~30 % 비율로 치환함으로써 소요 변형성능을 확보하면서 동시 경제적인 조인트 연결재료로 활용할 수 있는 것으로 나타났다.

• 대한정형외과학회지
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• 제54권4호
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• pp.317-326
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• 2019

목적: 인공관절 치환술 및 고관절 골절 환자에서 시행한 2가지 정맥혈전 색전증 예방요법의 준수율을 비교 분석하고자 하였다. 수술 후 발생하는 정맥혈전 색전증은 인공 슬관절 치환술이나 인공 고관절 치환술 및 고관절 골절 수술 후 발생하는 가장 심각한 합병증이다. 이에 대한 적절한 예방이 무엇보다 중요하기 때문에 항응고제 사용의 필요성 또한 증가하고 있다. 대상 및 방법: 2009년 3월부터 2011년 2월, 2012년 3월부터 2014년 2월까지 순천향대학교 부속 서울병원에서 인공 슬관절 치환술, 고관절 전치환술 및 고관절 골절로 고관절 반치환술 및 내고정술을 시행받은 환자들을 의무 기록과 영상 검사를 검토하여 각각 American College of Chest Physicians (ACCP) 가이드라인과 American College of Orthopedic Surgeons (AAOS) 가이드라인에 따라 시행한 정맥혈전 색전증 예방요법의 준수율을 후향적으로 비교 분석하였다. 결과: 인공관절 치환술 및 고관절 골절 환자에서 정맥혈전 색전증 예방을 위한 가이드라인이 적용되고 있으며 실제로 ACCP 가이드 라인에 따라 준수하고 있는 경우가 화학적 요법에서는 수술 전에 56.0%, 수술 후에는 67.0%, 물리적 요법에서는 80.5%의 준수율을 보였다. 또한 AAOS 가이드라인에 따라 준수하고 있는 경우가 화학적 요법에서는 74.1%, 물리적 요법에서는 88.3%의 준수율을 보이며 ACCP 가이드라인에 비해 높은 준수율을 보였다. ACCP 가이드라인의 수술 전 후 화학적 예방요법과 물리적 예방요법의 준수율과 AAOS 가이드라인의 화학적 예방요법과 물리적 예방요법의 준수율을 비교 분석하였으며, 인공 슬관절 치환술의 수술 전과 후, 고관절 골절 수술의 수술 전과 후, 전체 고위험군 수술에서 수술 전과 후 유의한 차이를 보였다(p<0.05). 결론: 정맥혈전 색전증 고위험군 수술에서 정맥혈전 색전증 예방요법의 가이드라인에 따른 준수율을 전반적으로 높여서 적절한 예방이 이루어지도록 해야 하며, 일선 정형외과의를 위한 통일된 방향의 가이드라인이 필요할 것이다.

• 대한골관절종양학회지
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• 제10권2호
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• pp.120-123
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• 2004

근위 경골부에 발생한 악성종양의 사지구제술은 화학요법의 발달로 인해 대표적인 치료 방법이 되었다. 다양한 술식의 보고에도 불구하고, 종양 절제 후 종양 대치물을 이용한 사지구제술에 있어 슬개건의 부착 부위가 상실되어 슬관절의 신전력을 재건 하기가 어려운 것이 공통적인 문제로 지적 되고있다. 본 연구는 경골 근위부의 종양을 절제한 후 저온열처리 한 다음 원위 대퇴골을 절제하여 저온열처리 자가경골 및 종양대치물과 결합하고, 슬개골을 자가경골과 결합된 원위 대퇴골에 고정하여 슬관절 신전력을 재건 한 2례를 보고하고자 한다.

• Advances in concrete construction
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• 제2권4호
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• pp.249-259
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• 2014

Mortar is a masonry product which is matrix of concrete. It consists of binder and fine aggregate and moreover, it is an essential associate in any reinforced structural construction. The strength of mortar is a special concern to the engineer because mortar is responsible to give protection in the outer part of the structure as well as at a brick joint in masonry wall system. The purpose of this research is to investigate the compressive strength and tensile strength of mortar, which are important mechanical properties, by replacing the cement and sand by stone dust. Moreover, to minimize the increasing demand of cement and sand, checking of appropriateness of stone dust as a construction material is necessary to ensure both solid waste minimization and recovery by exchanging stone dust with cement and sand. Stone dust passing by No. 200 sieve, is used as cement replacing material and retained by No. 100 sieve is used for sand replacement. Sand was replaced by stone dust of 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50% by weight of sand while cement was replaced by stone dust of 3%, 5%, and 7% by weight of cement. Test result indicates that, compressive strength of specimen mix with 35% of sand replacing stone dust and 3% of cement replacing stone dust increases 21.33% and 22.76% respectively than the normal mortar specimen at 7 and 28 days while for tensile it increases up to 13.47%. At the end, optimum dose was selected and crack analysis as well as discussion also included.

• 대한의용생체공학회:의공학회지
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• 제29권3호
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• pp.212-221
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• 2008

The total hip replacement (THR) has been used as the most effective way to restore the function of damaged hip joint. However, various factors have caused some side effects after the THR. Unfortunately, the success of the THR have been decided only by the proficiency of surgeons so far. Hence, It is necessary to find the way to minimize the side effect caused by those factors. The purpose of this study was to suggest the definite data, which can be used to design and choose the optimal hip implant. Using finite element analysis (FEA), the biomechanical condition of bone cement was evaluated. Stress patterns were analyzed in three conditions: cement mantle, procimal femur and stem-cement contact surface. Additionally, micro-motion was analyzed in the stem-cement contact surface. The 3-D femur model was reconstructed from 2-D computerized tomography (CT) images. Raw CT images were preprocessed by image processing technique (i.e. edge detection). In this study, automated edge detection system was created by MATLAB coding for effective and rapid image processing. The 3-D femur model was reconstructed based on anatomical parameters. The stem shape was designed using that parameters. The analysis of the finite element models was performed with the variation of parameters. The biomechanical influence of each parameter was analyzed and derived optimal parameters. Moreover, the results of FE A using commercial stem model (Zimmer's V erSys) were similar to the results of stem model that was used in this study. Through the study, the improved designs and optimal factors for clinical application were suggested. We expect that the results can suggest solutions to minimize various side effects.

• STI Policy Review
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• 제8권2호
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• pp.75-93
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• 2017

Recently, global competition in the manufacturing sector is driving firms in the manufacturing sector to conduct product innovation projects to maintain their competitive edge. The key points of product innovation projects are 1) what the purpose of the project is and 2) what expected results in the target market can be achieved by implementing the innovation. Therefore, this study focuses on the performance of innovation projects with a business viewpoint. In this respect, this study proposes the "achievement rate" of product innovation projects as a measurement of project performance. Then, this study finds the best strategies from various innovation activities to optimize the achievement rate of product innovation projects. There are three major innovation activities for the projects, including three types of R&D activities: Internal, joint and external R&D, and five types of non-R&D activities - acquisition of machines, equipment and software, purchasing external knowledge, job education and training, market research and design. This study applies decision tree modeling, a kind of data-mining methodology, to explore effective innovation activities. This study employs the data from the 'Korean Innovation Survey (KIS) 2014: Manufacturing Sector.' The KIS 2014 gathered information about innovation activities in the manufacturing sector over three years (2011-2013). This study gives some practical implication for managing the activities. First, innovation activities that increased the achievement rate of product diversification projects included a combination of market research, new product design, and job training. Second, our results show that a combination of internal R&D, job training and training, and market research increases the project achievement most for the replacement of outdated products. Third, new market creation or extension of market share indicates that launching replacement products and continuously upgrading products are most important.

• Journal of Medicine and Life Science
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• 제20권2호
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• pp.60-66
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• 2023

Gentamicin-loaded bone cement used in total joint arthroplasty is indispensable, as it provides stability by directly binding the surfaces of implants and bones. Depending on multiple factors, including the material of the bone cement used, common complications, such as aseptic loosening, osteolysis, and infection can occur postoperatively. In clinical practice, Doujet bone cement is easy to handle (pre-packed all-in-one system), and has shown low failure rates and non-inferior results compared with similar available products. We conducted a retrospective comparative study to analyze the clinical and radiological results of each bone cement group to establish the safety and usefulness of Doujet bone cement. From July 2020 to July 2022, we enrolled 198 patients in this study after an average follow-up period of 37 months (range, 6-48 months). In 99 patents, Doujet^® bone cement (Injecta, Gunpo, Korea) was used for total knee arthroplasty (TKA), while Refobacin^® bone cement (Biomet, Warsaw, IN, USA) was used in 99 patients. The average range of motion (ROM) of the knee increased by 2.4° (from 127.0° preoperatively to 129.4° postoperatively) in the Doujet group, and by 0.1° (from 128.7° to 128.8°) in the Refobacin group (P=0.701). The Western Ontario and McMaster Universities (WOMAC) osteoarthritis index scores decreased from 44.1 to 7.8 in the Doujet group, and from 44.2 to 6.3 in the Refobacin group (P=0.162). Complications, such as osteolysis or post-operative wound infection, did not occur in more than two cases in both groups. The WOMAC and ROM of the knee in both groups had no clinical differences. Both Doujet and Refobacin similarly showed low complication rates after TKA.

• 대한골관절종양학회지
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• 제2권1호
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• pp.8-17
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• 1996

The purpose of this study is a comparative evaluation of range motion, especially extension deficit between the group of total patellectomy and that of intact patella, after reconstruction of the patellar tendon in the prosthetic replacement of a proximal tibia. Between 1990 and 1994, 15 patients who had a primary malignancy on proximal tibia were operated on. All patients were evaluated clinically and radiographically. Two patients were excluded because one had a deep infection treated with arthrodesis of the knee and the other was a composite allograft. The mean follow-up of the 13 patients was 27 months(15-47), including 10 osteosarcomas, 1 chondrosarcoma, 1 malignant fibrous histiocytoma and 1 malignant giant cell tumor. Eleven patients had a resection of the proximal tibia and 2 had an extracapsular total knee resection with distal femur. Reconstruction of the defect was done in 8 cases with a custom-made Link Endo-Model Total Rotation Knee Joint Prosthesis, and in 5 with How Medica Modular Resection System (HMRS). We used two methods to reconstruct the ligamentum patellae. Fixation of the patellar tendon to the prosthesis only with suturing and/or stapling(group SS) was done in 7. Transposition of gastrocnemius muscle to enhance fixation and to cover the prosthesis(group TG) was done in 6. Regardless of fixation methods, total patellectomy was done in 5 either to lengthen the patellar tendon or to make primary skin closure easier or for both. In 8 cases, patella was left intact or resurfaced with polyethylene prosthesis. Active extension was measured while the patient was in a sitting position. There is no statistically meaningful difference in terms of extension deficit (Wilcoxon rank test, p=0.8800) between patellectomy group and intact patella group, and between group of fixation only with suturing and that of gastrocnemius transposition. Two cases of extension deficit over 30 degree were seen in group SS and in the group of intact patella. Conclusively, total patellectomy could be an option without increasing the risk of extension deficit when primary skin closure is difficult or patellar tendon is a little bit short to be fixed. There is no rating in the Enneking system of functional evaluation that this finding into consideration.