• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.103-104
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• 2019

The aim of the research is assessing the possibility of recovering the compressive strength of the mortar mixture replaced excessively high volume of blast furnace slag accidently. As a result of the experiment, in the case of compressive strength, painting sodium oxide showed higher compressive strength recovery effect than painting calcium oxide. As a curing temperature, 20℃ showed advanced result rather than 65℃. From the wet curing, the reaction was confirmed, deeper penetration depth was checked at 20℃ than 60℃ temperature. Therefore for the concrete mixture with excessively high volume of blast furnace slag, it is considered that painting sodium hydroxide and curing 20℃ can recover the compressive strength effectively.

• 한국가시화정보학회지
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• 제21권1호
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• pp.103-109
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• 2023

This research developed a measurement technique that can measure the oxygen temperature inside a high temperature furnace. Instead of measuring only changes in frequency components within a small range used in the existing variable laser absorption spectroscopy, laser spectroscopy technology was used to spread out wavelength of the light source passing through the gas Based on a total of 20,000 image data, research was conducted to predict the temperature of a high-temperature furnace using CNN with black and white images in the form of spectral bands by temperature of 25 to 800 degrees. The optimal model was found through Hyper parameter optimization, R2 score is 0.89, and the accuracy of the test data is 88.73%. Based on this research, it is expected that concentration measurement and air-fuel ratio control technology can be applied.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.30-35
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• 1995

This paper presents fundamental experiment for the properties of high performance concrete in its fresh and hardened state made with ground granulated blast-furnace (GGBF) slag. The result is that the effect of decreasing xoncrete temperature is to the mixing ratio of GGBF slag, but it presents disadvantage in the slump loss phase. In addition to, we know that the splitting tensile strength, compressive strength and elastic modulus of concrete mixed with high fineness GGBF slag are increased at age 28days.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제33회 KOSCO SYMPOSIUM 논문집
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• pp.151-155
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• 2006

The large amount of energy is consumed in a process for keeping the high temperature melting pool. For this reason, in addition to the wastes input to keep the high temperature melting pool, it is necessary for an auxiliary fuel and LOx to throw into the melting pool. So in this study, using a new melting furnace system, the experiments to keep the melting pool with minimal energy without throwing an auxiliary fuel and LOx was carried out. Also it is hoped that the results of the experiment will be available to analyze keeping a melting pool and behavior in a melting furnace.

• 대한기계학회논문집B
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• 제35권2호
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• pp.215-220
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• 2011

산업용 보일러의 열효율을 높이고 체적을 줄이기 위하여 0.5 t/h 급 무연소실 보일러를 개발하였다. 별도의 연소실이 없이 증발관이 화염에 노출된 구조에서 화염 안정성을 확보하기 위하여 금속섬유버너를 채택하였다. 증발관은 관군의 형태로 버너 하류에 배치되고 하류에 설치된 증발관에는 휜을 설치하여 열교환 면적을 확보하였다. 무연소실 보일러는 관군에 대한 열전달 관계식으로부터 설계하였고 본 연구에서는 시제품에 대한 실험 및 보일러 내부의 유동 및 열전달에 대한 수치해석을 수행하여 관군에 대한 관계식을 적용한 설계와 비교하였다.

• 한국건축시공학회지
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• 제14권1호
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• pp.37-44
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• 2014

건설산업에서는 탄산가스 저감을 위해 산업부산물을 다량 활용하는 기술개발을 위한 연구가 이루어지고 있다. 산업부산물 중 특히 고로슬래그 미분말은 잠재수경성에 기인하여 장기강도는 우수하나 초기강도가 낮기 때문에 많은 양을 대체하는데 한계가 있다. 이에 본 연구에서는 철강공정 중 용선예비처리 공정에서 발생하는 슬래그부산물을 활용하여 고활성 고로슬래그 미분말을 시험 제조후 고활성 고로슬래그 미분말의 모르타르 압축강도 강도발현 특성을 검토하였다. 또한, 고활성 고로슬래그 미분말 단독으로도 경화가 가능한 특징을 고려해서 2차 콘크리트 제품용 결합재로서 활용 가능성을 검토하고자 배합조건에 따른 콘크리트 제조 및 압축강도 발현특성을 검토하였다. 실험변수로써 슬래그부산물의 분말도, 치환율, 양생조건 및 W/B를 설정하였다. 그 결과 슬래그부산물을 자극제로 활용한 고활성 고로슬래그 미분말 모르타르의 압축강도 향상을 확인하였으며 고활성 고로슬래그 미분말이 단독으로도 경화가 가능하기 때문에 양생 및 배합조건을 고려하면 고활성 고로슬래그 미분말을 콘크리트 2차 제품용 결합재로서 활용 가능할 것으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.81-87
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• 2003

The purpose of this study is the development of a recycling process to recover the hydrated ability of cement hydrate which accounts for a large proportion of cementitious powder by concrete waste in order to recycle cementitious powder by concrete waste as recycle cement. Therefore, after having theoretical consideration based on the properties of high-heated concrete, we consider the properties of hydration of cementitious powder in hardened mortar under various temperature conditions. As a result of experiment, it is revealed that an effective development of recycling cement is possible since the cementitious powder by concrete waste recovers a hydraulic property during burning at $600^{\circ}C$ or $700^{\circ}C$. And it is shown that the fluidity of mortar decreases rapidly as the burning temperature of recycle cement increases. however, the improved effect of fluidity is predominant if adding the additive such as fly-ash or blast furnace slag.

• Steel and Composite Structures
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• 제23권5호
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• pp.611-621
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• 2017

This paper presents an investigation on the fire resistance of high strength fiber reinforced concrete filled box columns (CFBCs) under combined temperature and loading. Two groups of full-size specimens were fabricated. The control group was a steel box filled with high-strength concrete (HSC), while the experimental group consisted of a steel box filled with high strength fiber concrete (HFC) and two steel boxes filled with fiber reinforced concrete. Prior to fire test, a constant compressive load (i.e., load level for fire design) was applied to the column specimens. Thermal load was then applied on the column specimens in form of ISO 834 standard fire curve in a large-scale laboratory furnace until the set experiment termination condition was reached. The test results show that filling fiber concrete can improve the fire resistance of CFBC. Moreover, the configuration of longitudinal reinforcements and transverse stirrups can significantly improve the fire resistance of CFBCs.

• 열처리공학회지
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• 제16권6호
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• pp.320-328
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• 2003

A specimen of Cu-35%Sn alloy has been subjected to the unidirectional heat treatment in an attempt to examine the evolution of microstructures under varying thermal conditions. The specimen was cast in the form of a cylinder 10 mm in diameter and 200 mm in length, which was then installed in the temperature gradient field established inside a vertical tube furnace. The furnace temperature was adjusted to make the upper part at $750^{\circ}C$ and bottom end part at $300^{\circ}C$ of the specimen. The experiment was terminated by dropping it into water after the 30 minutes holding at given temperature. By the rapid cooling, the high temperature phases, ${\gamma}$ and ${\zeta}$, were retained at ambient temperature with some of ${\gamma}$ phase transformed to ${\varepsilon}$ phase, especially at the grain boundaries of ${\gamma}$ phase. The presence of ${\varepsilon}$ phase was found to determine the nature of phase transformations of the ${\zeta}$ phase undergoes upon cooling. In the close area of the ${\varepsilon}$ phase, ${\varepsilon}$ phase grew separately out of ${\zeta}$, and adds to the preexisting ${\varepsilon}$ whereas in areas away from ${\varepsilon}$, both ${\delta}$ and ${\varepsilon}$ grew simultaneously out of ${\zeta}$, and formed a lamella eutectoid structure. The transformation to ${\delta}$ was found to occur only in slow cooling. The hardness on each phase showed that the retained phases, ${\gamma}$ and ${\zeta}$, could be plastically deformed without brittle fracture while the phases, ${\varepsilon}$ and ${\delta}$, were too brittle to be deformed.

• 보존과학회지
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• 제34권6호
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• pp.581-593
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• 2018

최근 고대 제철기술 연구를 위한 복원실험이 활발하게 이루어짐에 따라 세부 기술체계나 조업방식 등에 대한 해석이 가능해지는 등 성과를 이루었다. 이에 본 연구에서는 고대 제련-단야기술 복원실험을 위한 적정 온도조건을 확인하여 고대 기술의 복원에 근접하기 위한 적정한 실험 방향을 제시하고자 하였다. 복원대상은 고대 중원지역의 출토 사례를 기본으로 하였으며 기존의 연구 자료를 참고하여 최대한 변수를 통제한 실험을 설계하였다. 저온으로 조업한 실험A와 고온으로 조업한 실험B를 실시한 결과 실험A에서 생성된 철은 탄소함량이 적고 단야조업에도 적합한 것으로 확인되었다. 또한 슬래그의 미세조직 및 성분조성과 노벽의 침식 등 전반적인 양상도 실험A가 고대 제련기술에 근접한 결과를 보였다. 실험을 통한 고대 제철기술의 복원은 유적에서 나타나는 현상의 복원될 때 이루어질 수 있으므로 고대제련-단야 기술체계의 복원을 위한 실험은 실험A와 같은 저온조업을 중심으로 진행되는 것이 적절할 것으로 판단된다.