• Fire Science and Engineering
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• v.27 no.5
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• pp.1-7
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• 2013

Fire at building can occur enormous damages to life, properties, and environment and the risk of fire breakout is going up higher because of application of combustible materials than before. Therefore, the steel industries are trying to develop fire resistant steel in order to sustain the load bearing capacity of steel structures during fire situation. In this paper, to give the basis data-bases for evaluation of structural stability of steel structures applied fire resistant steel, FR 490, the tests of mechanical and thermal properties at high temperature were conducted and the comparisons are done with the SM 490 that has the same mechanical one.

• Fire Science and Engineering
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• v.23 no.3
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• pp.31-39
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• 2009

Recently, fire resistance in high-rise building is becoming major problem socially. So it is need of hour to study on fire resistance in buildings. This study estimates fire resistance performance to utilized CFT (Concrete filled steel tube, below CFT) column in the high structure. But it is difficult quantitative evaluation about fire resistant performance of CFT. Therefore, this study made CFT specimen that determine the factor which is strength of concrete and then CFT column was exposed to heating controlled as closely as possible the ISO-834 standard fire curve. Also, tried to analyze internal temperature through nonlinear transient heat flow analysis. And, presumed extant compressive strength on the basis of this.

• 식품문화 한맛한얼
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• v.1 no.4
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• pp.23-28
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• 2008

고추는 우리나라 국민의 식생활에 있어 빠져서는 안 될 조미채소로 쌀 다음으로 농업총생산액이 가장 높으며 전체 채소 중 가장 많은 재배면적과 생산액을 차지하는 중요한 환금성 작물중의 하나다. 고추의 원산지는 열대 아메리카(미국 남부로부터 아르헨티나 사이에 분포)로 고온성 작물에 속하며 우리나라에 고추가 도입된 내력은 광해군 6년(1614년) 이수광이 저술한 "지봉유설"에 고추를 가리키는 '남만초'의 기록이 있고 그 도입경로가 왜국인 까닭에 '왜개자(倭芥子)'라고도 불렸으며 이것을 재배한다는 기록으로 보아 그 이전에 도입된 것으로 추정된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.617-624
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• 2021

Concrete-filled steel tubular columns can improve the strength and deformation capacity of structures, thereby enabling the development of efficient structures. The Korean design standard (KDS41) regarding concrete-filled steel tubular structures, established by the architectural institute of Korea in 2005, was revised in 2009 and 2016. The objective was to understand the compressive strengths and deformation capacity of stub columns for concrete-filled square steel tubes under uniaxial compression and validate the KDS41's standard code for necessary corrections. Experiments were conducted on 26 specimens with parameters, such as the width-thickness ratio of cold-formed square tubes. The following values of the stub columns for concrete-filled square steel tubes were obtained: compressive strengths, relationship between the axial load and axial displacement, and failure modes. An analysis of these results enabled an understanding of the concrete-filled effect and the influence of the wide-thickness ratio. The compressive strengths of filled concrete saw a 9% increase compared to a state of uniaxial stress, which must be noted in a future edition of KDS41. After benchmarking the results regarding square steel tubes generated by cold forming to the guidelines provided by the KDS41, the KDS41's value of 2.26 for the limiting width-to-thickness ratio for the compact section was found to be inflated. With a safety concern, this paper proposes a more conservative value of 1.35.

• Geotechnical Engineering
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• v.11 no.2
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• pp.51-70
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• 1995

Types of foundation of high rise buildings are primarily determined by loads transmitted from super structure, soil bearing capacity and available construction technology, The use of deep foundation of the buildings considered in this study due to the fact that rock of enough bearing capacity is not found down until 90~l00m. When a concentration of high soil pressure must be distributed over the entire building area, when small soft soil areas must be bridged, and when compressible strata are located at a shallow depth, mat foundation may be useful in order to have settlement and differential settlement of variable soils be minimized. The concept of mat foundation will also demonstrate some difficulties of applications if the load bearing demand directly carried down to the load -bearing strata exceeds the load -bearing capacity. This paper introduces both the analysis and design of mat type foundation for high rise buildings as well as the method-ology of modelling of the soil foundation, especially, engineered to redistribute the stress exceeding the soil bearing capacity. This process will result in the wide spread of stresses over the entire building foundation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.39-39
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• 2020

호박(Cucurbita spp.)은 박과 호박속 식물로 원산지는 열대 남아메리카로 추정되며 1년생 혹은 다년생 초본으로서 우리나라를 포함한 전 세계에서 널리 분포하고 있다. 호박은 비타민A와 비타민C가 풍부하고 이뇨작용 효과가 탁월해 피부를 좋게 하고 부기를 빼주는 것으로 보고되고 있다. 본 연구에서는 농업유전자원센터에서 보유한 호박속 자원의 내력과 형태적인 특성을 그룹화하여 자원 활용을 위한 기초자료를 제공하고자 하였다. 농업유전자원센터에서 보유한 호박속 등록자원은 총 5종(C.pepo, C. moschata, C.maxima, C.argyrosperma, C .ficifolia) 1,640자원으로 주요 원산지는 한국 589자원(35.9%), 미국 122자원(7.4%), 러시아 79자원(4.8%), 멕시코 49자원(4.2%), 터키 56자원(3.4%)이었으며 국내 원산의 경우 강원도에서 수집된 자원이 66자원으로 가장 많았다. 전체 1,640 자원 중 재래종은 733자원(44.7%)을 차지하였으며 다음으로는 육성품종이 133자원(8%)으로 많았다. 생장형이 조사 된 301자원 대부분이 덩굴성이며 준왜성 16자원, 왜성 14자원이 있었다. 호박은 과실 모양과 색, 잎 모양, 줄기 모양 등 생육 특성이 매우 다양하게 조사 되었으며 과경 등 몇 가지 특징은 완벽하지 않지만 종(species)을 구분하는 간이적인 지표로 사용되는 것으로 조사되었다. 흰가루병 저항성 자원은 조사 된 1,170 자원 중 우리나라 재래종인 참호박(IT104575)을 포함한 7자원이 조사되었다. 293개 자원의 과실당도는 2.2~15.4brix까지 다양했으며 당도 12brix 이상 자원은 IT200650을 포함하여 6자원이 조사되었다. 본 연구에서 조사된 호박속 자원의 내력 및 생육 특성은 육종소재의 기초 정보로서 이용되고 있으며 자원 내력정보의 보완, 형질과 기능성 물질 분석 등 추가적인 연구를 통해 연구소재의 기초 정보로서 활용의 가치가 더 커질 것으로 보인다.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.49-51
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• 2007

수분은 변압기 내부의 절연물의 절연내력에 악영향을 끼치므로, 변압기 열화진단의 중요한 요소이다. 이러한 수분을 검출하기 위한 여러 가지 방법들(Karl-Fischer법, Dew-Point법, RVM 등)이 개발되어졌고, 현재도 많은 연구가 진행되어 지고 있다. 본 논문에서는 회복전압측정법(RVM : Return Voltage Measurements)과 FDS(Frequency Domain Spectrum)를 이용하여 변압기의 여러 구성물(절연지, 전극, 절연유 등)들과 수분과의 반응 메커니즘을 분석하였다. 눈으로 확인할 수 없는 부분을 규명함으로서 앞으로 변압기 열화진단법들의 개발에 기여하고자 하였다.

• The Journal of Engineering Geology
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• v.30 no.2
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• pp.185-198
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• 2020

High-density rapid expansion material is a method that increases the solid volume of injection materials due to hydration and foam reactions at the same time as spraying. It is an effective method for securing ground stability, restoring subsidence, and loading during construction of structures. In this regard, through the mechanical experiments of injection materials, the stability of the foundation ground of the structure and the effect of increasing the endurance using site construction were analyzed. The results of the experiment showed that the unit weight of soil decreased by 10.5% after injection of the filling material, and the allowable support for the structure was deemed safe, and the subsidence by each section after ground improvement was determined to be safe at 2.28, 1.55 and 0.46 cm, respectively, with an acceptable subsidence of less than 5 cm. After the field test, five inclinometers were installed on the top floor of the target building to measure the displacement of the X and Y axes. As a result of the measurement, no displacement related to the phenomenon of inequality or subsidence cracks of the structure was measured for about 16 months (509 days) after construction. This can be judged to be a sufficient increase in the stability of the ground after the injection of rapid expansion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.440-447
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• 2020

Masonry structures are used as bearing walls in small buildings, but they are generally considered non-bearing walls. They are used as partition walls that divide the interior spaces of the frame structures of buildings. In addition, wetting techniques that use mortar as an adhesive between blocks or bricks in construction are vulnerable to climatic conditions, especially cracks in mortar, which can cause conduction collapse of the walls in seismic loading. The purpose of this research was to propose a dry concrete block construction method that complements the weak axial shear stiffness and improves the weakness of the wet construction method as well as to investigate its structural behavior. In this study, the material properties of concrete blocks were examined, and the seismic performance of the proposed dry assembly structure was verified by structural behavior tests on horizontal cyclic loads. First, in these study results, concrete blocks can be applied to the dry block construction method instead of wet construction methods because they secure more than C-type blocks in KS regulations. Second, the structural performance of the wall against a horizontal cyclic load indicates that the resisting force of the assembly block wall is increased by increasing the horizontal length of the wall, forming several diagonal cracks. Finally, the proposed dry block wall structure requires a seismic performance assessment considering that the ratio of the shape of the wall by height and length is considered a major influence variable on the structural behavior under a horizontal load.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.391-400
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• 2019

In the case of fire, a structure loses its original stiffness due to the temperature rise, and the load bearing capacity decreases. The loss of structural strength increases with increasing fire time of the structure. To prevent the collapse of buildings, it is very important to understand whether or not the members are damaged. On the other hand, there is insufficient data to be a guideline for diagnosing and evaluating the residual strength of the members in Korea. Therefore, this study examined the resistance performance by Finite-Element-Analysis of composite beams, which are composite structures among structural members. Composite beam modeling was carried out based on the model used in the Electrical Penetration Room (EPR) in cooperation with KEPCO. The heat transfer analysis and structural analysis of the critical phase were performed using ANSYS, a finite element analysis program. ANSYS was used to perform heat transfer analysis and structural analysis at the static analysis. To analyze the residual performance, the temperature distribution of the composite beam and the maximum displacement result of the heat-affected structure analysis were derived and the experimental data and the structural analysis result data were compared and analyzed.