• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
• /
• pp.200.1-200.1
• /
• 2010

Solar energy is one of the most promising energy resources in the future. For the application and dissemination of solar energy technologies in various fields, reliable data sets of solar irradiation are needed for engineers, researchers, businessmen, and policy makers. Global horizontal solar radiation is needed for the use of flat plate collector, solar domestic hot water system, photovoltaic devices and passive systems like green house. In many countries, solar radiation data accumulated for more then 40 or 50 years and typical weather data are published with average of more then 30 years. In Korea, those global total radiations are measured for about 30 years. With the connections of computer network, measured data could be transmitted to the central control system at key station through Ethernet lines. The data acquisition systems are connected to be automatically controlled by the monitoring network. Global horizontal solar radiation data 16 locations were measured and averaged from 1982 to 2008.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
• /
• pp.26-29
• /
• 2006

A flat plate-column connection is susceptible to brittle punching shear failure, which may result in the necessity of shear reinforcement. In present study, experimental tests were performed to study the capacity of slab-column connections strengthened with lattice, stud rail, shear band and stirrup under gravity and cyclic lateral load. Among them, the capacity of the specimens with lattice are superior to the others due to the truss action of the lattice bars and dowel action of the longitudinal bars as well as the shear resistance of the web re-bar. On the other hand, the strengths of the specimens with stud rail, shear band and stirrup are lower than the estimated strength by the ACI, therefore design formulas of the ACI are needed to revise.

• 콘크리트학회논문집
• /
• 제18권5호
• /
• pp.595-602
• /
• 2006

본 연구의 목적은 중력 하중에 저항하도록 설계된 플랫 플레이트 외부 접합부의 이력 거동을 평가하는 데 있다. 이러한 목적을 위하여 2/3의 크기가 조정된 PT 슬래브-기둥 외부 접합부 2개와 RC 슬래브-기둥 외부 접합부 1개를 대상으로 실험적 연구를 수행하였다. 여기서 각각의 PT 실험체는 서로 다른 강선 배치 형태를 띄고 있다. 중력 하중은 동일하게 설정하였고, 지속적인 정적 하중 하에서 유사 정적 횡하중을 적용하였다. 한편 모든 실험체는 ACI 318-05과 ACI 352.1R-89에 근거하여 기둥 폭 내에 하부 철근을 배근 하였다. 또한 PT 외부 접합부의 이력 거동에 대한 일반적인 결론을 얻기 위하여 기존 연구자들의 실험 결과와 함께 비교하였다. 이번 연구를 통하여 강선의 배치는 PT 접합부의 이력 거동을 결정하는 중요한 변수임을 확인하였다. 즉 횡변형 성능, 에너지 소산 능력, 파괴 메커니즘, 그리고 연성 능력이 강선의 배치에 따라 다르게 나타났다. 또한 ACI 352.1R-89에서 구조적 일체성을 위해 제공된 하부 철근의 양은 모멘트 역전에 의해 발생된 정모멘트를 저항하는데 있어서도 적절하다는 것이 밝혀졌다. 또한 실험체의 전단 강도는 강선의 포스트 텐션에 의한 평균 콘크리트 압축 응력($f_{pc}$)의 효과가 고려된 식이 그렇지 않은 식보다 전단 강도를 정확히 예측하는 것으로 나타났다.

• Advances in concrete construction
• /
• 제14권3호
• /
• pp.195-204
• /
• 2022

As a brittle failure mode, punching-shear failure can be widely found in traditional RC slab-column connections, which may lead to the entire collapse of a flat plate structure. In this paper, a novel RC slab-column connection with inner steel truss was proposed to enhance the punching strength. In the proposed connection, steel trusses, each of which was composed of four steel angles and a series of steel strips, were pre-assembled at the periphery of the column capital and behaved as transverse reinforcements. With the aim of exploring the punching behavior of this novel RC slab-column connection, a static punching test was conducted on two full-scaled RC slab specimens, and the crack patterns, failure modes, load-deflection and load-strain responses were thoroughly analyzed to explore the contribution of the applied inner steel trusses to the overall punching behavior. The test results indicated that all the test specimens suffered the typical punching-shear failure, and the higher punching strength and initial stiffness could be found in the specimen with inner steel trusses. The numerical models of tested specimens were analyzed in ABAQUS. These models were verified by comparing the results of the tests with the results of the analyzes, and subsequently the sensitivity of the punching capacity to different parameters was studied. Based on the test results, a modified critical shear crack theory, which could take the contribution of the steel trusses into account, was put forward to predict the punching strength of this novel RC slab-column connection, and the calculated results agreed well with the test results.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
• /
• pp.867-870
• /
• 2008

플렛 플레이트 구조시스템은 층고절감, 공기단축, 공간의 가변성 등 많은 장점들을 가지고 있다. 하지만 건물이 고층화 되어감에 따라 일반 RC 기둥을 사용할 경우 기둥의 크기가 과도하게 커지는 단점이 있다. 이러한 이유로 CFT 기둥의 사용이 증가하고 있지만 CFT 기둥-RC 무량판 접합부의 이력거동을 명확하게 규명하기 위한 기존 실험 연구는 국내외적으로 매우 부족한 실정이고 실험연구를 통해서는 한계가 있다. 본 연구에서는 비선형 유한요소해석을 실시하여 접합부의 이력거동을 분석하였다. 해석결과 유효폭 내에 배근되는 철근비가 증가하면 접합부의 모멘트 강도는 증가하지만 연성능력을떨어졌고 중력하중비가 증가할 경우 접합부의 모멘트강도와 연성능력이 모두 감소하였다. 전단머리의 길이가 0.27m 이상인 경우에는 길이가 증가할 때 다른 변수에 비해 접합부의 모멘트 강도와 연성능력에 주는 영향이 상대적으로 작았다. 슬래브두께가 증가할수록 초기강성 및 모멘트 강도가 증가하였다.

• 한국전산구조공학회논문집
• /
• 제31권6호
• /
• pp.315-329
• /
• 2018

최근 국내에서는 고층 벽식 아파트 건설 시, 하부 주차공간과 공용공간 확보를 위하여 RC 전이슬래브 시스템을 사용하는 경우가 증가하고 있다. 하지만 두께가 얇은 RC 무량판 슬래브를 위해 개발된 설계방법 및 구조성능평가 방법을 두께가 매우 두꺼운 전이슬래브 구조설계에 그대로 사용하고 있다는 문제점이 있다. 따라서 합리적인 전이슬래브의 구조설계를 위해서는 RC 전이슬래브 시스템의 2면 전단거동 양상에 대한 명확한 분석이 필요하다. 이에 따라 본 연구에서는 전이슬래브의 두께, 콘크리트 강도, 전단경간비, 철근비 등 다양한 설계변수에 따라 비선형 FEM을 이용하여 전이슬래브의 2면 전단거동을 분석하였다. 또한 비선형 FEM 해석결과와 기존의 2면 전단강도 평가식으로 예측한 전단강도를 비교분석하여 기존 평가식의 전이슬래브 2면 전단강도 평가 유효성을 검토하였다.

• Mycobiology
• /
• 제39권4호
• /
• pp.272-277
• /
• 2011

Chemical mutagenesis of basidiospores of Hypsizygus marmoreus generated new mushroom strains. The basidospores were treated with methanesulfonate methylester, an alkylating agent, to yield 400 mutant monokaryotic mycelia. Twenty fast-growing mycelia were selected and mated each other by hyphal fusion. Fifty out of the 190 matings were successful (mating rate of 26.3%), judged by the formation of clamp connections. The mutant dikaryons were cultivated to investigate their morphological and cultivation characteristics. Mutant strains No. 3 and No. 5 showed 10% and 6% increase in fruiting body production, respectively. Eight mutant strains showed delayed and reduced primordia formation, resulting in the reduced production yield with prolonged cultivation period. The number of the fruiting bodies of mutant No. 31, which displayed reduced primordial formation, was only 15, compared to the parental number of 65. Another interesting phenotype was a fruiting body with a flattened stipe and pileus. Dikaryons generated by mating with the mutant spore No. 14 produced flat fruiting bodies. Further molecular biological studies will provide details of the mechanism. This work shows that the chemical mutagenesis approach is highly utilizable in the development of mushroom strains as well as in the generation of resources for molecular genetic studies.

• Structural Engineering and Mechanics
• /
• 제89권4호
• /
• pp.363-374
• /
• 2024

Significant changes have been made to estimate the punching shear capacity for edge column-slab joints in the latest editions of most current codes. The revised equations account for axial forces as well as moments conveyed to columns from slabs, which have a substantial impact on the punching resistance of such joints. Many key design parameters, such as reinforcement-ratio, concrete strength, size-effect, and critical-section perimeter, were treated differently or even ignored in various code provisions. Consequently, wide ranges of predicted punching shear strength were detected by applying different code formulas. Therefore, it is essential to assess the various current Codes' design-equations. Because of the similarity in estimated outcomes, only the ACI, EC, and SNiP are used in this study to cover a wide range of estimation ranges from highly conservative to unconservative. This paper is devoted to analyzing the techniques in these code provisions, comparing the estimated punching resistance with available experimental data, and finally developing efficient models predicting the punching capacity of edge column-slab connections. 63 samples from past investigations were chosen for validation. To appropriately predict the punching shear, newly updated equations for ACI and SNiP are provided based on nonlinear regression analysis. The proposed equations'results match the experimental data quite well.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
• /
• pp.53-56
• /
• 2008

본 연구는 주거용 고층 건물에서 폭넓게 사용되고 있는 플랫 플레이트 구조에서 장방형 기둥-슬래브 접합부를 대상으로 실시한 6개의 실험결과를 분석한 것이다. 연구의 목적은 지진하중과 같이 반복적으로 작용하는 횡하중에 대하여 기둥 단면의 형상비(${\beta}$c=$c_1/c_2$)에 따른 접합부의 이력거동을 비교 평가 하는 것이다. 기둥 형상비는 $b_o$가 일정해 지도록 0.33${\sim}$3($c_1/c_2$=1/3, 1/1, 3/1)으로 선정하였다. 슬래브 휨철근비는 1.0%, 1.5%로 변화시켰으며, 중력전단력비($V_g/V_c$) 등 접합부의 이력거동에 영향을 줄 수 있는 다른 영향인자들은 일정한 조건으로 계획하여 기둥 형상비의 영향을 고찰할 수 있도록 하였다. 실험을 통해서 뚫림전단파괴 양상과 균열 패턴, 접합부의 강성, 변형능력 등을 변수에 따라 분석하였다.

• 환경영향평가
• /
• 제19권2호
• /
• pp.127-140
• /
• 2010

This study investigates the relation between the location of a habitat and the ecological connections according to the habitat type in the riparian zone at the Nonsan Stream and Yanghwa Stream. Stream habitat is classified into nine types for the aquatic insects and fish. For vegetation and birds, habitat is classified into two types of medium-scale streams, including both physical and chemical streams are analyzed accordingly. Nowadays, The fundamental goal of the river environment restoration enterprise is the rehabilitation or the restoration of the characteristic the river scenic or environment. For instance, The Channel habitats which has physical nature environment such as flat, speedy rapids, or closed-channel wetland, pool are constructed by artificial, Consequently, make them autogenesis smoothy eco-environment. However, the river environment are controlled not only physical environment, but it also need reasonable the quality of the water to compose smoothly. Finally, understanding what influence are effecting on physical habitat environment which are made by natural factors to water quality are very important factor for the river environment restoration enterprise Therefore, In this research, we are targeting to a basin to investigate the environment of the physical channel habitat and evaluate the changing of the water quality. This results will be a important characteristic that can judge the physical habitat and reciprocality connected to the water quality or adequacy of restoration technology. Therefore in this study, as a step to quantify functions and values of habitats and definite factors to perform habitat, we selected a representative stream of sand-stream, gravel-stream to classify habitat characteristics and quantified the physical, chemical, biological characteristics.