• Earthquakes and Structures
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• 제4권2호
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• pp.203-217
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• 2013

In recent decades, it has been realized that increasing the lateral stiffness of structure subjected to lateral loads is not the only parameter enhancing safety or reducing damage. Factors such as ductility and damping govern the structural response due to lateral loads. Despite the significant contribution of damping in resisting lateral loads, especially at resonance, there is no accurate mathematical representation for it. The main objective of this study is to develop a damping identification procedure for linear systems based on a mixed numerical-experimental approach, assuming viscous damping. The proposed procedure has been applied to a laboratory experiment associated with a numerical model, where a hollow rectangular steel cantilever column, having three lumped masses, has been fixed on a shaking table subjected to different exciting waves. The modal damping ratio has been identified; in addition, the effect of adding filling material to the hollow specimen has been studied in relation to damping enhancement. The results have revealed that the numerically computed response based on the identified damping is in a good fitting with the measured response. Moreover, the filling material has a significant effect in increasing the modal damping.

• 대한건축학회논문집:구조계
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• 제34권6호
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• pp.19-27
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• 2018

The stone pagoda structure is treated as a discontinuous masonry structure, and the contact surface characteristics between stones is a very important factor in the discontinuum behavior analysis. So, it is necessary to find out material and structural characteristics of stone contact surface to perform the structural analysis for safety evaluation. Accordingly, it is important to analyze the material properties of stone surface and secure the structural characteristics through various contact surface states. Therefore, in this study, various test specimens applying the filler between the surface roughness and the stone in the contact surface treatment technique of the stone pagoda were manufactured, and compression test and shear test were carried out. Also, we analyzed the material and structural characteristics of the stone contact surface through the comparison of experimental results.

• 한국구조물진단유지관리공학회 논문집
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• 제6권3호
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• pp.177-184
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• 2002

The most tunnel damage such as cracks or leakage which exist in tunnel lining commonly, is caused by the cavities where exist behind the tunnel lining, through the tunnel safety inspections. These cavities were analysed to affect a stability of a running-tunnel seriously. This study is on the development of the controlled low-strength and flowable filling material which is able to apply to the cavity behind the tunnel lining. The major materials of backfilling developed are a crushed sand and a stone-dust which exists as a cake-state and is a by-product obtained in the producting process of aggregate. It is conformed with the design standard to the physical characteristics of backfilling. The backfilling material developed is designed to reduce the fair amount of cement. According to the designed compound ratio, it is carried out the laboratory tests such as a compressive strength and a chemical analyses and is applied to dilapidated old tunnel for an application assessment.

• 터널과지하공간
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• 제17권3호
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• pp.175-185
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• 2007

불연속면을 따라 점토 등의 충전물이 포함된 경우에는 불연속면의 방향이 유리하게 작용하더라도 사면안정에 불안정성을 초래한다. 연구지역의 사면활동은 점토충전물과 풍화토의 경계를 따라 발생하였다. 이것은 물성의 차이를 보이는 경계부분이 존재했기 때문이며, 암석에서 엽리 등이 구조적 운동시 연약대로 작용하여 층간의 미끄러짐을 유도하는 현상과 매우 유사하다. 대부분의 해석에서 점토충전물이 존재할 경우에는 하나의 불연속면으로 설정하여 해석한다. 이때의 불연속면은 점토층내에서의 활동면으로 해석되므로 점토와 원지반과의 경계부의 특성이 해석에 고려되지 못하여 불연속면의 거동은 결국 점토의 물리적 성질에 많이 지배된다. 점토충전물로 인한 활동사면의 안정성 평가 결과는 충전물에 의한 불연속면의 파괴유형에 따른 강도정수에 의해 안전율에 상당한 차이를 보인다.

• 한국건축시공학회지
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• 제12권5호
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• pp.510-517
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• 2012

This study evaluated the recycling potential of in-site waste soil as pile back filling material (PBFM). We performed experiments to check workability, segregation resistance, bond strength, direct shear stress test, and dynamic load test using in-site waste soil in coastal areas. We found that PBFM showed better performance than general cement paste in terms of workability, segregation resistance, and bond strength. On the other hand, the structural performance of PBFM was slightly lower than that of general cement paste due to the skin friction force of pile by Pile Driving Analyzer and direct shear stress. However, because this type of performance degradation in terms of structure can be improved through the use of piles with larger diameter or by changing the type of pile, considering the economics and environment, we considered that recycling of PBFM has sufficient value.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1370-1376
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• 2010

In this study, usability and stability in the caisson filling material were reviewed that copper salg(one million tons per one-year) were produced by smelter. In order to complete these studies, chemical and physical comparing analyses were performed by sea-sand materials as to the materials suitability, After construction, the structural displacement of caisson was measured by the instrument and was examined for stability. As a result of analysis, it was determined that copper slag is eco-friendly, and can be used as recycled alternative to aggregates materials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.81-84
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• 1995

A reliable bonding between two silicon wafers, regularly grooved and non-grooved, was done by the direct boning technology, It is Presented that high structural duality was realized not only at the bended interface but in the bulk, commensurate with the filling of artificial grooves, which would be attributed to the dislocation-gettering capability of groove free-surfaces during annealing. The groove filling would be explained with mass-transport phenomena assisted by the dislocation movement from initial contact boundaries toward groove surfaces. Intrinsic voids can be easily removed by aid of the grooves. The proposed method yielded also an intimate bonding not only between {111} wafers strongly misoriented and slightly inclined to {111} basal plane but even between {111} and {100} orientation wafers.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권3호
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• pp.6-13
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• 2016

The effect of blast oxygen furnace (BOF) slag used as filling materials on the soil environment was studied using column tests that simulated the flow of the BOF slag leachate through the soil layer. The Cu, Mn, Zn, Ni, and F contents of the leachate affected soil were similar to that of the controls (i.e., soils that were not affected by the leachate). The As, Cd, and Pb contents were lower in the leachate affected soils than the controls. The changes in these contaminants contents can be attributed to the interactions between anions such as alkalinity generating anions (e.g., CO₃²⁻, HCO₃⁻, OH⁻) or calcium ions with heavy metals or F, which consequently affected the fate of heavy metals and F in the leachate affected soils. The germination and growth of Spinapis alba in the soils affected by the leachate and the controls were also similar. However, the proportion of alkalophilic bacteria in the soils affected by the leachate significantly increased, and this can be explained by the increased soil pH due to the alkaline leachate. Overall, this study shows that the alkalinity of the BOF slag leachate, rather than the presence of heavy metals and F in the leachate, needs to be considered when the BOF slag is to be reused as structural filling materials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.3-6
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• 2001

In common globular proteins, the native form is in its most stable state. However, the native form of inhibitory serpins (serine protease inhibitors) and some viral membrane fusion proteins is in a metastable state. Metastability in these proteins is critical to their biological functions. Our previous studies revealed that unusual interactions, such as side-chain overpacking, buried polar groups, surface hydrophobic pockets, and internal cavities are the structural basis of the native metastability. To understand the mechanism by which these structural defects regulate protein functions, cavity-filling mutations of a 1-antitrypsin, a prototype serpin, were characterized. Increasing conformational stability is correlated with decreasing inhibitory activity. Moreover, the activity loss appears to correlate with the decrease in the rate of the conformational switch during complex formation with a target protease. We also increased the stability of a 1-antitrypsin greatly via combining various stabilizing single amino acid substitutions that were distributed throughout the molecule. The results showed that a substantial increase of stability, over 13 kcal/mol, affected the inhibitory activity with a correlation of 11% activity loss per kcal/mol. The results strongly suggest that the native metastability of proteins is indeed a structural design that regulates protein functions and that the native strain of a 1-antitrypsin distributed throughout the molecule regulates the inhibitory function in a concerted manner.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.3-6
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• 2001

In common globular proteins, the native form is in its most stable state. However, the native form of inhibitory serpins (serine protease inhibitors) and some viral membrane fusion proteins is in a metastable state. Metastability in these Proteins is critical to their biological functions. Our previous studies revealed that unusual interactions, such as side-chain overpacking, buried polar groups, surface hydrophobic pockets, and internal cavities are the structural basis of the native metastability. To understand the mechanism by which these structural defects regulate protein functions, cavity-filling mutations of ${\alpha}$1-antitrypsin, a prototype serpin, were characterized. Increasing conformational stability is correlated with decreasing inhibitory activity. Moreover, the activity loss appears to correlate with the decrease in the rate of the conformational switch during complex formation with a target protease. We also increased the stability of ${\alpha}$1-antitrypsin greatly via combining various stabilizing single amino acid substitutions that were distributed throughout the molecule. The results showed that a substantial increase of stability, over 13 kcal/mol, affected the inhibitory activity with a correlation of 11% activity loss per kcal/mol. The results strongly suggest that the native metastability of proteins is indeed a structural design that regulates protein functions and that the native strain of e 1-antitrypsin distributed throughout the molecule regulates the inhibitory function in a concerted manner.