가토 두개골 결손 모델에서 Bioglass가 첨가된 불소화 수산화인회석의 골재생능력

안효준(Hyo-Joon Ahn),한세진(Se-Jin Han),김경욱(Kyung-Wook Kim) 대한구강악안면외과학회 2011 대한구강악안면외과학회지 Vol.37 No.5

Introduction: Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 , HA) is the main inorganic phase of human hard tissue that is used widely as the repair material for bones. When HA is applied to a bony defect, however, it can be encapsulated with fibrous tissue and float in the implanted area due to a lack of consolidation. Bioceramics as allogenic graft materials are added to HA to improve the rate and bone healing capacity. Fluoridated hydroxyapatite (Ca 10 (PO 4 ) 6 (OH,F) 2 , FHA), where F- partially replaces the OH- in hydroxyapatite, is considered a good alternative material for bone repair owing to its solubility and biocompatibility. Materials and Methods: This study was designed to determine the bone healing capacity of FHA newly produced as a nanoscale fiber in the laboratory. HA and FHA with bioglass was implanted in a rabbit cranium defect and the specimen was analysed histologically. Results: 1. At 4 weeks, fibrous connective tissue and little bone formation was observed around the materials of the experimental group I implanted HA and bioglass. Newly formed bone was observed around the materials in the experimental group II implanted FHA and bioglass. 2. At 8 weeks, the amount of newly formed and matured bone was higher in experimental group II than in experimental group I and the control group. Conclusion: These results suggest that FHA and bioglass is a relatively favorable bone substitute with biocompatibility and better bone healing capacity than pure HA and bioglass.

국내 PSC교량 대표모델 생성과 지진취약도 분석

안효준(An, Hyo Joon),장지원(Jang, Ji Won),신수봉(Shin, Soobong) 대한토목학회 2019 대한토목학회 학술대회 Vol.2019 No.10

정적 변형률 데이터를 사용한 CNN 딥러닝 기반 PSC 교량 손상위치 추정

한만석,신수봉,안효준,Han, Man-Seok,Shin, Soo-Bong,An, Hyo-Joon 한국BIM학회 2020 KIBIM Magazine Vol.10 No.2

As the number of aging bridges increases, more studies are being conducted on developing effective and reliable methods for the assessment and maintenance of bridges. With the advancement in new sensing systems and data learning techniques through AI technology, there is growing interests in how to evaluate bridges using these advanced techniques. This paper presents a CNN(Convolution Neural Network) deep learning based technique for evaluating the damage existence and for estimating the damage location in PSC bridges using static strain data. Simulation studies were conducted to investigate the proposed method with error analysis. Damage was simulated as the reduction in the stiffness of a finite element. A data learning model was constructed by applying the CNN technique as a type of deep learning. The damage status and its location were estimated using data set built through simulation. It was assumed that the strain gauges were installed in a regular interval under the PSC bridge girders. In order to increase the accuracy in evaluating damage, the squared error between the intact and measured strains are computed and applied for training the data model. Considering the damage occurring near the supports, the results of error analysis were compared according to whether strain data near the supports were included.

교량기초 종류 및 지반-구조물 상호작용을 고려한 지진취약도 분석

김선재 ( Sun-jae Kim ),안효준 ( Hyo-joon An ),송기일 ( Ki-il Song ) 한국구조물진단유지관리공학회 2020 한국구조물진단유지관리공학회 논문집 Vol.24 No.6

구조해석을 시행함에 있어 기초는 소성힌지모델로서 고정단으로 간주되고는 한다. 본 연구에서는 기초가 고정단일 때, 2m깊이의 기반암에 시공된 직접기초일 때, 그리고 기반암 심도 10m~20m 구간에 시공된 말뚝기초일 때의 기초, 교각, 교좌장치의 변위를 비교하였으며 기초에 가해지는 전단력을 비교하고, 한계 상태에 대하여 손상 확률을 계산하고 비교하였다. 고정단으로 계산되었을때 기초부 변위가 0m에 수렴하였으나, 심도 2m의 기반암 위에 시공된 직접기초는 상대적으로 변위가 발생하였고, 심도 18m의 기반암에 선단부가 관입되도록 시공된 말뚝기초는 더 큰 변위를 보였다. 또한 하부구조물인 기초의 변위가 상부구조물의 변위에도 영향을 끼치는 것으로 분석되었으나, 기초부분에 가해지는 전단력에는 세 가지 경우에 대하여 차이가 미미하였다. 교각 상단의 변위에 끼치는 영향은 직접기초와 말뚝기초간에 차이가 없는 반면, 고정단으로 가정하고 해석되었을 때와는 큰 차이가 있었다. In performing the structural analysis, the foundation is considered to be a fixed end as a plastic hinge model. In this study, the displacements of the foundation, pier, and shoe were compared when the foundation modeled as a fixed end, a shallow foundation constructed on bedrock of 2m depth, and a pile foundation constructed in the 10m to 20m depth of bedrock. The shear force was also compared, and the probability of damage was calculated and compared for the critical condition. When calculated as a fixed end, the displacement of the foundation converged to 0mm, but the shallow foundation built on the bedrock with a depth of 2m caused relatively displacement, and the pile foundation constructed to contact the bedrock with a depth of 18m caused a larger displacement. In addition, it was analyzed that the displacement of the foundation, which is the lower structure, affects the displacement of the super structure, but the difference in shear force applied to the foundation was insignificant in the three cases. There was no difference between the shallow foundation and the pile foundation in the influence on the displacement of the top of the pier, but there was a big difference from the analysis assuming as a fixed end.

FMS자료를 활용한 국내 PSC 대표교량의 지진취약도 분석

장지원(Jang, Ji Won),안효준(An, Hyo Joon),신수봉(Shin, Soo Bong) 대한토목학회 2020 대한토목학회 학술대회 Vol.2020 No.10

RC 슬래브교의 신축이음 손상과 바닥판 응답과의 상관관계 분석

정현진 ( Hyun-jin Jung ),안효준 ( Hyo-joon An ),박기태 ( Ki-tae Park ),정규산 ( Kyu-san Jung ),김유희 ( Yu-hee Kim ),이종한 ( Jong-han Lee ) 한국구조물진단유지관리공학회 2021 한국구조물진단유지관리공학회 논문집 Vol.25 No.6

우리나라 노후화 교량 중 많은 부분을 차지하는 RC 슬래브 교량은 대부분이 교량 안전 관리 및 유지관리의 대상인 1, 2종 교량에 포함되지 않는다. 또한 고속도로 교량에서 가장 높은 손상율을 차지하는 부속시설은 신축이음과 교량 받침부이다. 특히, 신축이음부를 통한 누수는 콘크리트 교량의 열화를 유발하고 균열 및 철근부 노출 등의 원인이 된다. 따라서 본 연구에서는 RC 슬래브교의 신축이음부 유간 밀착 손상이 바닥판 응답에 미치는 영향을 분석하였다. 양단 신축이음의 유간이 밀착된 경우 바닥판의 교축방향 변위가 발생되지 못해, 양쪽 단부 콘크리트에서 균열이 발생하였다. 또한, 응답 결과를 바탕으로 손상시나리오 별 신축이음부의 교축방향 변위와 바닥판 양단 콘크리트 응력과의 상관관계를 분석하고, 손상발생이 교량 거동에 미치는 영향을 파악하였다. 신축이음 장치 양면손상이 발생한 경우 변위와 응력과의 상관관계는 차량이 모든 차선을 지날 때 0.18로 낮은 상관성을 보였다. 무손상 상태와 비교했을 때도 바닥판 처짐은 차량이 지나는 동안 0.34~0.53, 차량이 지나간 후 0.17~0.43으로 낮은 상관성을 보였다. 이는 단부 콘크리트의 균열 발생으로 바닥판 전체 거동에 변화가 생긴 것을 의미한다. 따라서 바닥판 응답 데이터 기반 상관관계 분석과 이를 활용한 데이터 기반의 손상탐지가 가능하며, 이를 통해 바닥판 손상 및 열화의 원인이 되는 신축이음부의 조기 보수 및 보강, 사전관리에 기여하여 많은 도움이 될 것으로 기대된다. RC slab bridges account for the largest portion of deteriorated bridges in Korea. However, most RC slabs are not included in the first and second classes of bridges, which are subject to bridge safety management and maintenance. The highest damaged components in highway bridges are the subsidiary facilities including expansion joints and bearings. In particular, leakage through expansion joints causes deterioration and cracks of concrete and exposure of reinforced bars. Therefore, this study analyzed the effect of adhesion damage at expansion joints on the response of the deck in RC slab bridges. When the spacing between the expansion joints at both ends was closely adhered, cracks occurred in the concrete at both ends of the deck due to the resistance rigidity at the expansion joints. Based on the response results, the correlation analysis between displacements in the longitudinal direction of the expansion joint and concrete stress at both ends of the deck for each damage scenario was performed to investigate the effect of the occurrence of damage on the bridge behavior. When expansion joint devices at both sides were damaged, the correlation between displacement and stress showed a low correlation of 0.18 when the vehicles proceeded along all the lanes. Compared with those in the intact state, the deflections of the deck in the damaged case at both sides showed a low correlation of 0.34 to 0.53 while the vehicle passed and 0.17 to 0.43 after the vehicle passed. This means that the occurrence of cracks in the ends of concrete changed the behavior of the deck. Therefore, data-deriven damage detection could be developed to manage the damage to expansion joints that cause damage and deterioration of the deck.

리튬 유황전지용 폴리우레탄 고분자 전해질의 전기화학적 특성

김형주,신준호,김종화,김기원,안효준,안주현,Kim, Hyeong-Ju,Shin, Joon-Ho,Kim, Jong-Hwa,Kim, Ki-Won,Ann, Hyo-Jun,Ahn, Ju-Hyun 한국전기화학회 2002 한국전기화학회지 Vol.5 No.2

본 연구에서는 높은 인장강도와 탄성력을 가지는 다공성 폴리우레탄(polyurethane, PU)을 지지체(matrix)로 이용하고, 유기 전해액 ethylene carbonate(EC), propylene carbonate(PC), tetraethylene glycol dimethylether(TG)와 1M $LiCF_3SO_3$를 부피비 1:1 비율로 혼합하여 액체 전해액을 제조하였으며, 높은 이론용량을 가지는 Li/S전지에 적용하여 전기 화학적 특성을 조사하였다. 1M $LiCF_3SO_3$에 TG를 첨가할 경우 유기 전해액의 함침량이 약 $750\%$ 증가하였으며 방전용량$(1065mAh/g{\cdot}sulfur)$ 및 사이클 특성이 가장 우수하였다. 1M $LiCF_3SO_3$에 TG/EC(v/v,1:1) 및 PC/EC(v/v,1:1)를 첨가한 경우 이온 전도도는 각각 $3.15\times10^{-3}(S/cm)$ 와 $3.18\times10^{-3}(S/cm)$로 나타났다. Polyurethane was used as matrix for polymer electrolytes with liquid electrolyte consist of organic solvent as ethylene carbonate(EC), propylene carbonate(PC), and tetraethylene glycol dimethylether(TG) and 1M $LiCF_3SO_3$, which has high mechanical strength and porosity. Electrochemical properties fur polyurethane electrolytes with various liquid electrolytes were evaluated. The amount of immersed liquid electrolyte for TG with 1M $LiCF_3SO_3$ was increased to about $750\%$ by weight, and initial discharge capacity and cycle performance was better than others. Ionic conductivity for TG/EC(v/v,1:1) and PC/EC(v/v, 1:1) with 1M $LiCF_3SO_3$ was about $3.15\times10^{-3} S/cm, \;3.18\times10^{-3}S/cm$

RC 슬래브 교량의 철근 부식률에 따른 교량 안전성 분석

박주현(Park, Ju-hyun),한만석(Han, Manseok),안효준(An, Hyo Joon),민지영(Min, JiYoung),이종한(Lee, Jong-Han) 대한토목학회 2020 대한토목학회 학술대회 Vol.2020 No.10

Ni/MH 전지용 수소저장합금의 특성

안효준 국립경상대학교 공과대학 부설 첨단소재연구소 1994 尖端素材 Vol.4 No.-

In recent years a small sealed Ni/MH battery for cordless appliances has been extensively studied. The MH electrode characteristics were dependent on the fabrication method of alloys. The hydrogenation behavior of Ti-Ni powders prepared by mechanical alloying in a high energy ball mill have been investigaed by P-C-Isotherm curves, DSC(Differential Scanning Calorimetry), X-ray diffractometer, SEM(Scanning Elertron Microscope). Amorphous TiNi phase was formed 10 milling hours. The hydrogen storage capacity gradually decreased as a function of mechanical alloying time. There appears the DSC endothermic peak due to hydrogen evolution of amorphous hydride phase.

경량 고강도 Mg-Zn계합금의 조직과 내식성에 관한 연구

안효준,남태현,임수근,안인섭,허보영,김기원 慶尙大學校 1995 論文集 Vol.34 No.1

The purpose in this study is to develope of high strength and corrosion reistant Mg-Zn system alloys by controlling microstructures and by adding of Cu elements. To produce optimum tesile strength,it is imperative to obtain effective grain refinment during casting. Optimal condition for grain size refining effect was obtained at the minmum composotion of 2wt% Cu or 1.5wt%So addition to Mg-6wt%Zn alloy.Age hardening behavior was experimented at the optimal compositions of the Mg-6wt%Zn, Mg-6wt%Zn-2wt%Cu and Mg-6wt%Zn-1.5wt%Si. The hardeness increment due to age hardening was at the Mg-Zn-Si alloy system. The improvement of corrosion resistanece by the addition with Cu is related to and increasing Zn/Cu ration in the intermatallic particles in the Mg-Zn system.Further improvements obtained by T6 treatment are related to the properties of the Mg-Zn phase,whih acts as a corrosion barrier by precipitating along the grainboundaries.Filiform corrosion observed soon after pit initiation and cellular form of pit propagation later in chloride media are explained in terms of solid solution matrix structure and the properties of air formed oxide.The information obtained from the fundamental research work is utilized in suggesting ways of improving the corrosion resistance of commercial AZ91.