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심미 포스트가 전치에 미치는 응력과 변위에 관한 삼차원 유한요소법적 분석
권태훈,황정원,김성훈,신상완,Kwon Tae-Hoon,Hwang Jung-Won,Kim Sung-Hun,Shin Sang-Wan 대한치과보철학회 2003 대한치과보철학회지 Vol.41 No.5
Statement of problem : Most posts are metallic, but in response to the need for a post that possesses optical properties compatible with an all-ceramic crown. an esthetic post has been developed. Although there have been many studies about the esthetic post materials, 3-dimensional finite element studies about the stress distribution of them are in rare. Purpose : The purpose of this study is to investigate comparatively the distribution of stresses of the restored, endodontically treated maxillary incisors with the esthetic post materials and the displacement on the cement layer on simulated occlusal loading by using a 3-dimensional finite element analysis model. Material and method : Four 3-dimensional finite element models were constructed in a view of a maxillary central incisor, a post, a core, and the supporting tissues to investigate the stresses in various esthetic posts and cores and the displacement on the cement layer (Model 1 ; Cast gold post and core, Model 2 ; Glass fiber post with composite core, Model 3 ; Zirconia post with composite core. Model 4 ; Zirconia post with ceramic core). Force of 300N was applied to the incisal edge and the cingulum (centric stop point) with the angle of 135-degree to the long axis of the tooth. Results : 1. The stresses and displacement on the incisal edge were higher than on the cingulum 2. The stresses in dentin were the highest in Model 2 (Glass fiber post with composite core), and the second was Model 3, the third Model 1, and the lowest Model 4. 3. The stresses in post and core were the highest in Model 4 (Zirconia post with ceramic core), and the second was Model 1, the third Model 3, and the lowest Model 2. 4. The displacement on the cement layer was the highest in Model 2 (Glass fiber post with composite core), and the second was Model 3, the third Model 1, and the lowest Model 4. Conclusion : When a functional maximum bite force was applied, the distribution of stresses or the esthetic post and core materials and the displacement on the cement layer were a little different. It seems that restoring extensively damaged incisors with esthetic post and core materials would be decided according to the remaining tooth structure.
소방공무원에서 탄력성이 외상후스트레스 증상과 해리에 미치는 영향 : 우울의 매개 효과
권태훈,현소연,정영기,임기영,노재성,강대용,하귀염,김남희,Kwon, Tae Hoon,Hyun, So Yeon,Chung, Young Ki,Lim, Ki Young,Noh, Jae Sung,Kang, Dae Ryong,Ha, Gwiyeom,Kim, Nam Hee 한국정신신체의학회 2016 정신신체의학 Vol.24 No.1
연구목적 본 연구는 소방공무원에서 탄력성이 외상후스트레스 증상 및 해리에 미치는 영향과 함께, 탄력성과 각 외상후스트레스 증상 및 해리의 관계에서 우울의 매개효과에 대해서 알아보고자 하였다. 방 법 총 115명의 소방공무원을 대상으로, 생활사건 체크리스트, 사건충격척도-개정판, 해리경험척도, 벡 우울척도, 코너-데이비슨 탄력성 척도를 시행하였다. 탄력성이 외상후스트레스 증상과 해리에 미치는 영향 및 우울의 매개효과를 확인하기 위해 구조방정식모형(Structural equation modeling)과 경로분석(path analysis)을 실시하였다. 결 과 탄력성이 높을수록 낮은 외상후스트레스 증상과 낮은 해리를 보였으며, 각 탄력성과 외상후스트레스 증상 및 해리의 관계는 우울이 완전 매개를 하는 것으로 나타났다. 즉, 탄력성이 외상후스트레스 증상 및 해리에 대해 직접적인 영향이 아닌 우울을 통해 간접적으로 각 증상을 감소시킴을 보여주었다. 결 론 본 연구는 소방공무원에서 외상후스트레스 증상 및 해리의 예방과 치료에 있어 탄력성 강화와 우울 증상 감소를 목표로 한 임상적 개입이 중요함을 시사한다. Objectives : This study aimed to investigate the effects of resilience on posttraumatic stress symptoms and dissociation and whether depression mediates the relationships between resilience and posttraumatic stress symptoms and dissociation. Methods : A total of 115 firefighters participated in the study. Data were collected via the Life Events Checklist, Impact of Event Scale-Revised, Dissociative Experience Scale, Beck Depression Inventory, and Connor-Davidson Resilience Scale. Structural equation modeling and path analysis were applied to estimate the relationships between resilience, depression, posttraumatic stress symptoms, and dissociation. Results : Greater resilience was associated with lower posttraumatic stress symptoms and dissociation, and the relationship between them was fully mediated by depression. Conclusions : Specific aspects of depression may help explain the relationships between resilience and posttraumatic stress symptoms and dissociation. Tailored prevention programs and treatments based on resilience and depression may prevent posttraumatic stress symptoms and dissociation in firefighters and improve treatments outcomes among firefighters with posttraumatic stress symptoms and/or dissociation.
245kV 가스절연개폐장치의 내진성능 실증을 위한 시험 및 해석
김유경(Yu-Gyeong Kim),권태훈(Tae-Hoon Kwon),정영진(Yeong-Jin Jeong),김홍태(Hong-Tae Kim),김영중(Young-Joong Kim) 대한기계학회 2013 大韓機械學會論文集A Vol.37 No.5
가스절연개폐장치(GIS)는 안정적인 전력공급을 위한 대규모 설비이다. 최근 전력설비의 내진성능 검증이 중요해짐에 따라 진동대를 이용한 실제적 내진 시험이 요구되고 있지만, 진동대 규모의 한계로 해석에 기반한 평가가 주로 진행되고 있다. 그러나 해석법은 실제 거동을 모사하기 어려워 결과의 신뢰도가 낮으므로 타당한 해석법 개발이 필요하다. 본 연구에서는, 시험과 해석을 병행하여 대형 전력기기인 245kV GIS의 내진성능을 검증하였고, 결과를 비교 분석하여 대형 구조물용 내진 해석 기법의 타당성을 평가하였다. 245kV GIS는 해석과 시험법에서 충분한 안전성을 보였고, 해석의 결과는 시험과 10% 이내의 차이를 보였다. 높은 신뢰성의 원인으로 질량, 강성, 입력 가속도를 분석하였다. 본 연구는 내진 시험을 수행 할 수 없는 대형 전력기기의 내진성능 실증에 활용될 수 있을 것으로 기대된다. Gas insulated switchgear is large-sized electric equipment for providing a reliable supply of electric power. Recently, seismic tests of electric equipment using a shaking table have been mandated because seismic performance has become an increasingly important issue. However, basic analysis methods continue to be used because some electric equipment is too large for shaking table facilities. Thus, a reliable analysis method should be developed for large-scale electric equipment. This study aims to evaluate the seismic qualification of a 245kV GIS in accordance with IEEE-693 and to validate the analysis method by comparing it with test results. Both the test and the analysis showed that the 245kV GIS has proper seismic safety. Furthermore, the differences between the analysis and the test results are less than 10% for an accurately given mass, stiffness, and input acceleration. It is expected that this study can be used for the seismic qualification of large-scale electrical structures.
245㎸ 초고압차단기의 내진성능 실증을 위한 시험 및 해석
김유경(Yu-Gyeong Kim),권태훈(Tae-Hoon Kwon),정영진(Yeong-Jin Jeong),김홍태(Hong-Tae Kim),김영중(Young-Joong Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
Gas Insulated Switchgear (GIS) is a huge size of electric equipment for providing reliable electric power. As the seismic performance of electric equipments becomes increasingly important, the actual seismic qualification by shaking table test is required. In this study, design of the representative test model is performed for seismic qualification of 245㎸ GIS. Prior to the actual seismic test, modal and response spectrum analyses are carried out to predict the structural behavior of proposed model. Using the proposed test model, seismic qualification test is conducted in accordance with IEEE-693 standard. The seismic performance of the test model is qualified via the seismic test and analysis. To check the validity of the test model, results of both analysis and test are compared from the dynamic and structural point of views. From the results, it is concluded that the 245㎸ GIS meets the criteria for seismic qualification with a proper safety margin. It is expected that the developed test model can be used for the seismic performance on the whole GIS system.