• Structural Engineering and Mechanics
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• 제78권4호
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• pp.387-401
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• 2021

This paper provides a methodology to analyze the seismic performance of different component designs in hybrid masonry structures (HMS). HMS, comprised of masonry panels, steel frames and plate connectors is a relatively new structural system with potential applications in high seismic areas. HMS dissipate earthquake energy through yielding in the steel components and damage in the masonry panels. Currently, there are no complete codes to assist with the design of the energy dissipation components of HMS and there have been no computational studies performed to aid in the understanding of the system energy dissipation mechanisms. This paper presents parametric studies based on calibrated computational models to extrapolate the test data to a wider range of connector strengths and more varied reinforcement patterns and reinforcement ratios of the masonry panels. The results of the numerical studies are used to provide a methodology to examine the effect of connector strength and masonry panel design on the energy dissipation in HMS systems. We use as test cases two story structures subjected to cyclic loading due to the availability of experimental data for these configurations. The methodology presented is however general and can be applied to arbitrary panel geometries, and column and story numbers.

• 한국지반공학회논문집
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• 제23권10호
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• pp.13-22
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• 2007

최근 액상화 이후의 구조물 거동에 관심이 높아지면서, 액상화 지반의 과잉간극수압 소산에 대한 연구가 활발히 이루어지고 있다. 본 연구에서는 포화된 수평모래지반에 대한 원심모형실험을 수행하여 액상화 이후의 과잉간극수압 소산거동을 계측하고 계측결과를 바탕으로 견고화층의 비선형적인 두께 변화에 대한 예측모델을 제안하였다. 기존의 침강이론과 압밀이론에 이 예측모델을 결합함으로써 과잉간극수압 소산을 모델링하는 새로운 소산 예측모델을 개발하였다. 개발된 소산모델은 원심모형실험 결과와 비교하여 견고층 두께 증가와 과잉간극수압 소산양상을 잘 모사하는 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 연약지반처리위원회 학술세미나
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• pp.42-58
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• 2000

본 연구의 목적은 연약지반의 압밀계수 측정에 있어 Piezocone 관입시험을 이용할 때 관입시험자체의 정확성과 시험결과들에 미치는 여러 가지 지반공학적 영향요소들을 고려하려는데 있다. 본 연구의 연구실험방법으로는, Piezocone 관입을 위한 연약모형지반 조성을 위하여 초대형 Slurry Consolidometer에 Free Stress 상태의 Slurry를 45일간 압밀시킨 후 Automatic Computer Control Calibration Chamber (LSU/CALCHAS; Louisiana State University Calibration Chamber System)에 옮긴후 다시한번 압밀시키는 Two-Stage Consolidation Method를 사용하였다 동시에 연약모형지반내에 8개의 Piezometer를 설치하여 Piezocone 관입시 유발되는 지반 내에서의 과잉간극수압의 변환을 측정하였다. 총 25개의 Piezocone 시험중 4개는 Standard 10$\textrm{cm}^2$ Piezocone이고, 나머지 21개는 Miniature Piezocone이 사용되었다. 모형지반은 여러 가지 Boundary Condition들과 Stress Condition 그리고 Stress History등을 고려하여 조성되었다. 또한 Dissipation Test직후의 압밀특성을 확인하기 위하여 0.01초당 한 개이상의 실측점을 측정할 수 있는 Digital-Oscilloscope를 이용하였다. 특히 Dissipation Test, 즉시 Piezocone의 Filter Element에 잡히지 않는 과잉간극수압의 Initial Drop 존재에 관한 기존의 추측을 실제 실험치로 확인할 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.365-368
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• 2003

Despite of the simple equipment and operation, DMT has been widely used to obtain various soil parameters and those parameters have been successfully applied to geotechnical design practice. Among them, the estimation of horizontal coefficient of consolidation is so useful that many researchs recently have been carried out. However, simulation of the penetration of the DMT blade is complex due to the inherent difficulty on analyzing a plane strain deformation of the soil around blade. Therefore, empirical and semi-empirical methods that use the theoretical solution developed fur piezocone with some assumptions have been used to estimate the coefficient of consolidation from Dilatometer dissipation test. In this paper, coefficients of consolidation c$\_$h/ which were obtained using equivalent radius that is same area with the DMT blade and optimization technique are compared with those obtained from Oedometer test and other interpretation methods. It was found that a new method used in this study can give more precise horizontal coefficient of consolidation than other methods do.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.130-134
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• 2008

The increasing size of very large scale integration (VLSI) circuits, high transistor density, and popularity of low-power circuit and system design are making the minimization of power dissipation an important issue in VLSI design. Test Power dissipation is exceedingly high in scan based environments wherein scan chain transitions during the shift of test data further reflect into significant levels of circuit switching unnecessarily. Scan chain or cell modification lead to reduced dissipations of power. The ETC algorithm of previous work has weak points. Taking all of this into account, we therefore propose a new algorithm. Its name is RE_ETC. The proposed modifications in the scan chain consist of Exclusive-OR gate insertion and scan cell reordering, leading to significant power reductions with absolutely no area or performance penalty whatsoever. Experimental results confirm the considerable reductions in scan chain transitions. We show that modified scan cell has the improvement of test efficiency and power dissipations.

• 한국지반공학회논문집
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• 제18권2호
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• pp.137-146
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• 2002

본 연구에서는 국내 해성퇴적 연약지반의 압밀특성을 실험적으로 규명하기 위하여 현장에서의 픽에조콘을 이용한 간극수압소산시험을 수행하고 동일한 위치와 심도에서 채취한 비교란시료를 이용하여 실내에서 Howe cell 압밀시험을 포함한 역학시험과 물성시험을 수행하였다. 이를 근거로 howe cell 압밀시험으로부터 구한 수평압밀계수$(c_r)$와 피에조콘 소산시험으로부터 구한 압밀도 50%에 해당하는 소산시간$(t_{50})$의 관계를 회귀분석을 통하여 실험식을 제안하였으며 이 실험식과 기존의 여러 학자들에 의해 제안된 이론해와의 관계를 비교하였다. 이에 의하면 실린더형 공동팽창이론에 근거한 Torstensson(1977)의 이론해와 변형률경로법에 근거한 Houlsby와 Teh(1988)의 이론해에 비교적 유사한 경향을 보이는 것으로 나타났다

• 한국지반공학회논문집
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• 제19권5호
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• pp.145-154
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• 2003

본 연구에서는 정규압밀점토에서의 피에조 콘 소산시험시 측정된 초기 과잉간극수압을 팔면체 수직응력($\Delta{\sigma}_{oct}$)의 변화에 의해 발생하는 과잉간극수압($\Delta{u}_{oct}$)과 팔면체 전단응력($\Delta{\tau}_{oct},$)의 변화에 의해 발생하는 과잉간극수압($\Delta{u}_{shear}$)으로 구분할 수 있는 방법을 이용하여 초기 과잉간극수압 분포를 가정하고, 연속적인 구형 공동확장 이론과 축대칭 비혼합 선형 압밀이론에 근거한 유한차분법을 사용하여 과잉간극수압의 소산거동을 모사하였다. 이와 같은 방법에 의해 압밀계수를 가정하여 계산된 소산곡선이 실측된 소산곡선과 특정 소산도에서 일치하도록 반복 계산하는 시행착오법을 사용하여 압밀계수를 산정하는 방법을 제안하였다. 제안된 방법과 기존의 이론해를 루이지애나 주립대학교 모형 토조에서 수행된 소형 피에조 콘의 시험결과에 적용한 결과에 의하면 제안된 방법에 의해 산정된 압밀계수가 다른 이론해보다도 실내시험치와 유사한 것으로 나타났으며, 계측된 소산곡선과도 잘 일치하는 것으로 나타났다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.308-318
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• 2000

This paper introduces the acceptance criteria for reinforced concrete moment frames based on structural testing of ACI in preparing and proposes criteria for acceptable limiting drift and energy dissipation ratios of reinforced concrete shear walls for structural testing. Limiting drift and energy dissipation ratios were examined for tests on shear walls having ductile type failures. Test data were analyzed and compared to results for a suggested acceptance criteria that involves a limiting drift that is a function of aspect ratio a limiting energy dissipation ratio that is a function of displacement ductility and damping.

• 오토저널
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• 제5권1호
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• pp.89-93
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• 1983

This paper describes on experimental investigation into the heat dissipation of Diesel engine, placing emphasis on the variations of compression ratio and cooling water temperature. The engine used for this test was a vertical single-cylinder four-cycle type, having a direct injection. Engine performance and heat transfer rates was tested under the compression ratio 14.3 and 17.4. In this study, the results showed that output and transfer rates of engine decrease in accordance with the decrease of compression ratio. The effect of cooling water temperature and injection delay of fuel on the heat dissipation brings about the decrease of heat transfer rates from cylinder to cooling water.

• Corrosion Science and Technology
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• 제19권1호
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• pp.23-30
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• 2020

Heat sinks are most widely used in thermal management systems; however, the heat dissipation efficiency is usually limited. Therefore, in order to increase heat dissipation efficiency of the heat sink, the heat-dissipating paint using 2D materials (hexagonal boron nitride (h-BN) and graphene) as thermally conductive additive was designed and evaluated in the present study. The heat dissipation performance of the paint was calculated from temperature difference between the paint-coated and -uncoated specimens mounted on the heat source. The highest heat dissipation performance was obtained when the ratio of h-BN to resin was 1/10 in the paint. In addition, further reduction in the temperature of the test specimen by 6.5 ℃ was achieved. The highest heat dissipation performance of the paint prepared using graphene was achieved at a 1/50 ratio of graphene to the resin, and a 6.5 ℃ reduction was attained. In addition, graphene exhibited enhanced corrosion resistance property of heat-dissipating paint by inhibiting the growth of the paint blisters.