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복합재-알루미늄 단일겹침 하이브리드 체결부 강도 특성 실험 연구
김중진(Jung-Jin Kim),성명수(Myeong-su Seong),김홍주(Hong-Joo Kim),차봉근(Bong-Keun Cha),권진회(Jin-Hwe Kweon),최진호(Jin-Ho Choi) 한국항공우주학회 2008 韓國航空宇宙學會誌 Vol.36 No.9
본 연구에서는 탄소 복합재와 알루미늄 2024-T3 단일겹침 체결부에 대해, 체결방법을 접착, 리벳, 리벳/접착 하이브리드의 세 가지로 변화시키면서 체결방법에 따른 파손하중과 파손모드를 실험을 통해 연구하였다. 세 가지 체결방법에 대해 각각 겹침길이 3가지와 적층순서 2가지, 총 82개의 시편을 제작하였다. 접착제는 FM73m, 리벳은 NAS9308-4-03을 사용하였다. 접착 체결과 하이브리드 체결에서는 겹침길이가 커짐에 따라 파손하중이 증가하였고, 리벳 체결에서는 겹침길이에 따른 파손하중 변화가 나타나지 않았다. 단순 접착 및 리벳 체결부에서는 적층순서에 따른 일관된 경향을 발견하기 어려운 반면, 하이브리드 체결부에서는 인접층의 적층각 차이가 작은 적층판을 사용한 체결부의 파손하중이 높게 나타났다. 접착 체결과 하이브리드 체결의 주된 파손모드는 층간분리이고 리벳 체결은 국부적 베어링 파손을 동반한 리벳 파손으로 나타났다. Strength and failure of composite-to-aluminum rivetted, bonded, and rivet/bonding hybrid single-lap joints were investigated by experiment. A total of 82 joint specimens were tested with 3 different overlap lengths and 2 types of stacking sequence. FM73m adhesive film and NAS9308-4-03 rivet were used for hybrid joints. While failure loads of the bonded and hybrid joints increased as the overlap length increased, failure loads of the rivetted joints were not affected by the overlap length. Effect of the stacking sequence was not remarkable in the simple bonded or rivetted joints. Failure loads of the hybrid joints, however, showed the maximum of 30% difference depending on the stacking sequence. Major failure mode of the bonded and hybrid joints was the delamination of the composite adherend and failure mode of riveted joints was the rivet failure with local bearing.
장인산(Insan Jang),송근수(Geun-Su Song),김민근(Min-Keun Kim),최동순(Dong-Soon Choi),최항문(Hang-Moon Choi),차봉근(Bong-Kuen Cha) 대한치과교정학회 2021 대한치과교정학회 임상저널 Vol.11 No.2
This case report describes the treatment of an inversely impacted maxillary first premolar in a 12.6-year-old girl by autotransplantaion and comprehensive orthodontic treatment. Four months after surgery, brackets were placed, and orthodontic force was applied. After orthodontic treatment, the transplanted premolar showed favorable stability and occlusion with a little short root length. This case demonstrates a successful treatment modality for an inversely impacted premolar with prolonged retention of a primary molar.
차봉근,서정훈 대한치과교정학회 1990 대한치과교정학회지 Vol.20 No.1
This study was undertaken to investigate the difference of chin morphology and mandibular form in relation to different mandibular growth direction. The subject was divided into three group i.e., control group, vertical group, and horizontal group, according to the criteria of Bjork sum, and each group was composed of 15 females and 15 males. Medial axis analysis in addition to the routine cephalometric analysis using P.I.A.S. (personal image analysing system) was carried out to find out the differences of mandibular morphology on each group. The results were as follows: 1. The area of symphysis was larger in horizontal growth group than that of vertical growth group. 2. Protruding chin area was also larger in horizontal growth group than that of vertical growth group. 3. There was a close correlationship between protruding chin area and other form of mandible. 4. Antegonial notch depth and ramus posterior contour depth was deeper in vertical growth group than in horizontal growth group, and antegonial notch depth was more influenced by anterior part of notch than posterior part of notch. 5. Mental medial axis and incisal medial axis length, in relation to corpus medial axis length was larger in vertical growth group than in horizontal growth group.
점진적 Distraction Technique을 이용한 상악골의 전방이동
박영욱,차봉근,김지혁 대한악안면성형재건외과학회 2000 Maxillofacial Plastic Reconstructive Surgery Vol.22 No.6
Several surgical and/or orthodontic procedures have been used in maxillary protraction. Currently procedures with the use of distraction osteogenesis have been studied by many investigators and applied to various clinical situations and this procedure is rapidly becoming an alternative technique to treat craniofacial growth disturbances and dysplasias. So we performed distraction osteogenesis for 12-year old young patient with maxillary hypoplasia, and 7-year old young patient with severe maxillary deficiency due to unilateral cleft lip & palate. First we performed incomplete Le Fort I osteotomy(pterygomaxillary dysjunction and no maxillary downfracturing) and then tried to protract the maxilla by way of extraoral device, Delaire type face mask. During the follow-up period of 12 months and 13 months respectively, we could attain the successful results by analysis of lateral cephalometrics in facial profiles. So we suggest that this maxillary distraction technique is one of the excellent therapeutic choices in the treatment of growing children with maxillary deficiency.
Cha, Bong-Keun,Lee, Suk-Keun 대한치과교정학회 2000 대한치과교정학회지 Vol.30 No.6
부갑상선 호르몬이 과도하게 분비되는 경우 전반적인 골의 탈석회화에 의해 골막성 골흡수 및 골의 동통 등의 증상이 발현될 수 있다. 본고에서 소개된 환자의 경우 광범위한 치근 흡수를 동반한 부정교합 환자로, 임상 및 두부 방사선 계측사진 분석에서 상악 열성장과 하악 과성장이 동반된 골격성 Ⅲ급 부정교합으로 진단되었으며, 병리검사결과 부갑상선 호르몬 및 성장 호르몬의 수치가 증가된 것으로 보아 부갑상선 기능항진증으로 판단되었다. 방사선 사진 분석 결과 광범위한 치근의 흡수를 관찰할 수 있었으며 골다공증과 유사하게 골소주 형태가 매우 성기면서 ground glass 양상을 보였다. 이와 같이 부갑상선 기능항진증에 의해 골질뿐만 아니라 치근이 영향을 받은 것은 매우 드문 경우로 생각된다. 또한 부갑상선 기능항진증에 의해 내장두개의 골침착이 감소될 수 있다는 동물실험 결과를 볼 때 Ⅲ급 부정 교합의 원인이 상악 열성장인 점과 연관하여 매우 흥미고운 점으로 지적된다. 따라서 부갑상선 기능항진증의 다양한 증상 및 양태에 대한 조기진단 및 이에 대한 지식은 교정진단 및 치료에 중요한 역할을 할 수 있다고 생각된다. Excessive production of parathyroid hormone causes bony disorder such as periosteal bone resorption and bone pain due to excessive skeletal demineralization, A Class III facial deformity case with generalized root resorpion presented here was turned out to be due to hyperparathyroidism. Clinical and cephalometric analysis revealed a straight skeletal profile with a retruded maxilla and a prognathic mandible. The x-ray findings demonstrated generalized root resorption of entire dentition to different degree. There also appeared osteoporosis like immature trabecular structure with the evidence of ground glass appearance. Serum test showed elevated level of parathyroid hormone and growth hormone. Change of cranial growth by hyperparathyroidism can be dependent upon a decreased bone apposition in viscerocranial growth site and abnormalities in cranial suture growth. It is possible to hypothesize that growth retardation of maxilla at least partially be accounted for hyperparathyroidism. Therefore, regarding to the definite etiology of skeletal Class III and orthodontic treatment planning considering root resorption and osteoporosis, the early diagnosis for the hyperparathyroidism should be carefully carried by clinical and laboratory studies.