• 한국건축시공학회지
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• 제19권3호
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• pp.219-228
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• 2019

본 연구의 목적은 저점도형 고성능 감수제가 혼화재료를 포함하는 시멘트 계열 재료의 유동성 및 레올로지 특성에 미치는 영향을 분석하여 기초적인 정보를 제공하는 것이다. 이에 플라이애시, 고로슬래그, 실리카흄을 치환한 시멘트 페이스트와 모르타르에 대하여 일반적인 고성능 감수제와 저점도형 고성능 감수제를 사용하여 실험을 실시하였다. 실험 결과 저점도형 고성능 감수제는 소성점도에 있어서 일반형 고성능 감수제보다 크게 저감시키는 것으로 나타났다. 이러한 결과를 바탕으로 본 연구가 향후 저점도형 고성능 감수제를 사용하는 데에 기초적인 데이터를 제공할 것으로 기대한다.

• 한국초등과학교육학회지:초등과학교육
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• 제38권1호
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• pp.73-86
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• 2019

The purpose of this study is to investigate the characteristics of problem solving strategies that gifted students use in science inquiry problem. The subjects of the study are the notes and presentation materials that the 15 team of elementary and junior high school students have solved the problem. They are a team consisting of 27 elementary gifted and 29 middle gifted children who voluntarily selected topics related to dimple among the various inquiry themes. The analysis data are the observations of the subjects' inquiry process, the notes recorded in the inquiry process, and the results of the presentations. In this process, the knowledge related to dimple is classified into the declarative knowledge level and the process knowledge level, and the strategies used by the gifted students are divided into general strategy and supplementary strategy. The results of this study are as follows. First, as a result of categorizing gifted students into knowledge level, six types of AA, AB, BA, BB, BC, and CB were found among the 9 types of knowledge level. Therefore, gifted students did not have a high declarative knowledge level (AC type) or very low level of procedural knowledge level (CA type). Second, the general strategy that gifted students used to solve the dimple problem was using deductive reasoning, inductive reasoning, finding the rule, solving the problem in reverse, building similar problems, and guessing & reviewing strategies. The supplementary strategies used to solve the dimple problem was finding clues, recording important information, using tables and graphs, making tools, using pictures, and thinking experiment strategies. Third, the higher the knowledge level of gifted students, the more common type of strategies they use. In the case of supplementary strategy, it was not related to each type according to knowledge level. Knowledge-based learning related to problem situations can be helpful in understanding, interpreting, and representing problems. In a new problem situation, more problem solving strategies can be used to solve problems in various ways.

• 한국광학회지
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• 제1권1호
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• pp.98-106
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• 1990

Lasers are used increasingly for specialized engineering applications such as drilling, profile cutting, welding and surface heat-treatment(hardening, alloying, annealing0 of metals and non-metals. The most important characteristics of lasers used for these materials-processing applications are reviewed, with special emphasis on the importance of the controlled heating process. In addition to these processes, some optical devices and supplementary equipment used in laser processing are introduced. Finally, some examples shows the wide variety of laser capability for substitution of traditional materials processing.

• Computers and Concrete
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• 제12권6호
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• pp.755-774
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• 2013

Considering the well known environmental issues of cement manufacturing (direct and indirect levels of $CO_2$ emissions), clinker replacement by supplementary cementing materials (SCM) can be a very promising first step in reducing considerably the associated emissions. However, such a reduction is possible up to a particular level of SCM utilization, influenced by the rate of its pozzolanic reaction. In this study a (4-step) structured methodology is proposed in order to be able to further adjust the concrete mix design of a particular SCM, in achieving additional reduction of the associated levels of $CO_2$ emissions and being at the same time accepted from a derived concrete strength and service life point of view. On this note, the aim of this study is twofold. To evaluate the environmental contribution of each concrete component and to provide the best possible mix design configuration, balanced between the principles of sustainability (low environmental cost) and durability (accepted concrete strength and service life ). It is shown that such a balance can be achieved, by utilising SCM by-products in the concrete mix, reducing in this way the fixed environmental emissions without compromising the long-term safety and durability of the structure.

• 영어어문교육
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• 제16권3호
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• pp.183-206
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• 2010

The purpose of this study was to investigate whether using English newspapers as supplementary teaching materials for the present textbook could increase students' English reading ability, interest in class and their willingness to take an active part in activities. Schools in rural areas, compared to urban schools, did not have the appropriate resources to teach students effectively. Understanding the disadvantages of the students in rural areas, one idea was to use newspapers to inspire the students to reach outside their local community and incorporate new styles of English and cultural aspects into their lives. The participants were 2nd grade high school students in the rural area. The experimental group received reading lessons with the textbook and English newspapers. They were also encouraged to make their own portfolios. The control group received reading lessons with the textbook and other supplementary materials. Before and after the experiment, reading comprehension tests as well as the questionnaires of interest and self-directed learning were administered. The results of this study were as follows: First, students' English reading ability was significantly improved in the experimental class using English newspapers. Second, students' interest and self-directed learning were positively increased in the same class above.

• Computers and Concrete
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• 제22권2호
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• pp.183-196
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• 2018

The rheological behaviour of high strength self compacting concrete (HS-SCC) studied through an experimental investigation is presented in this paper. The effect of variation in supplementary cementitious materials (SCM) $vis-{\grave{a}}-vis$ four different types of processed crushed sand as fine aggregates is studied. Apart from the ordinary Portland cement (OPC), the SCMs such as fly ash (FA), ground granulated blast furnace slag (GGBS) ultrafine slag (UFS) and micro-silica (MS) are used in different percentages keeping the mix -paste volume and flow of concrete, constant. The combinations of rheology, strength and durability are equally important for selection of mixes in respect of high-rise building constructions. These combinations are referred to as the rheo-strength and rheo-durability which is scientifically linked to performance based rating. The findings show that the fineness of the sands and types of SCM affects the rheo-strength and rheo-durability performance of HS-SCC. The high amount of fines often seen in fine aggregates contributes to the higher yield stress. Further, the mixes with processed sand is found to offer better rheology as compared to that of mixes made using unwashed crushed sand, washed plaster sand, washed fine natural sand. The micro silica and ultra-fine slag conjunction with washed crushed sand can be a good solution for high rise construction in terms of rheo-strength and rheo-durability performance.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.23-24
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• 2021

The use of recycled concrete aggregates (RCA) as a substitute for natural aggregates in new concrete produces both economic and environmental advantages. Most of the RCA applications for pavements have been primarily applied to support layers for roads and airfields. This paper summarizes a work completed at the University of Illinois in partnership with the O'Hare Modernization Program to examine the effect of coarse and fine RCA on the concrete's fresh and hardened properties for airfield rigid pavement applications. Ten different RCA concrete mixtures were prepared with the incorporation of different percentages of RCA fines as well as replacement of cement with high volume percentages of supplementary cementitious materials such as Class C fly ash and ground granulated blast furnace slag to improve the workability and long-term properties of RCA concrete. All the mixes on this stage included 100% recycled coarse aggregates and the Two-Stage Mixing Approach was used as a mixing procedure. Based on the results obtained in the research, mixes with high percentages of recycled fine and coarse aggregates could be used for construction of airfield concrete pavements in conjunction with supplementary cementitious materials

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.127-128
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• 2022

In order to realize carbon neutrality in the international society, research on supplementary cementitious materials(SCMs) has been actively conducted as a way to reduce carbon dioxide emissions in the cement industry. However, the use of SCMs causes problems of initial hydration delay and strength reduction due to the reduction of tricalcium silicate(C3S) in the cement clinker. Therefore, in this study, the initial hydration and basic characteristics of cement mortar were confirmed by adding a C-S-H based hardening acceleration to blended cement mixed with Portland cement, blast furnace slag, fly ash, and limestone power. As a result of the heat of hydration and compressive strength test, it was confirmed that when hardening acceleration was added, the initial reactivity was high, so the heat of hydration was promoted, and the initial strength was increased. It is considered to be due to C-S-H seeding effect. Therefore, it is judged that the use of C-S-H based hardening acceleration can supplement the problem of initial hydration delay of blended cement in Korea.

• 핵의학기술
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• 제26권1호
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• pp.15-26
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• 2022

최근 한국원자력안전기술원의 방사성폐기물의 자체처분을 심사하는 과정에서 많은 보완을 거치게 되고, 기관별로 자체처분 최종 승인 과정에 도달하는데 어려움을 겪고 있다. 이에 따라 최근 보완사항의 사례를 분석하여 자체처분의 처리 효율을 높이고 안전성을 강화하고자 한다. 2018년부터 2021년까지 20개 기관별 방사성폐기물 자체처분 절차서 및 계획서 작성 시 보완 요청된 사항들을 비교 검토 하였다. 이와 관련하여 원자력안전법 규정을 기준으로 심사 처리기간 산출 및 심사 과정에서 발생한 보완요청 사항들을 정리하여 방사성폐기물 자체처분 시 서류에 필요한 세부 작성안들을 도출하였다. 한국원자력안전기술원의 대표적인 보완요청사항들은 방사성폐기물의 종류 및 핵종별 보관기간 산출, 포장 용기 등에 대한 내용, RASIS 보고 방법, 자체처분 예정 저장 방법 최종 처분업체 확인, 폐필터의 보관기간 산출, 방사성마크 부착 등이 중요하게 부각되고 있다. 최신 보완사항들을 반영한 가이드라인의 기대효과로는 서류 작성에 필요한 시간단축 및 업무처리 효율성의 증대와 방사성폐기물 보관실의 저장효율성 향상 및 경제적 비용절감이 있었다. 이 연구에서 제시한 방사성폐기물 자체처분 가이드라인을 현장에 적용한다면, 고충을 겪고 있는 관계자들의 업무효율 향상에 도움이 될 것으로 사료 된다.

• 한국의상디자인학회지
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• 제8권2호
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• pp.61-71
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• 2006

The purpose of this study is to present a contents production process for costume design analysis by take advantage of the image media of Chinese historical backgrounds. The production process of contents for lectures on fashion design analysis can be summarized as follows: The contents for the design analysis of Chinese costumes can be divided into major media and supplementary media. Major media can be completed through the processes including the selection of Chinese historical backgrounds. images and media (video, DVD title or VOD), verification of image capture parts, image captures, and applications of PPT files. Supplementary media consist of production of analysis materials for each item and TPO, report preparation methods and discussions, and printed matters to be used at the stage of image comparison and verification. This way, a process applicable to the design analysis of Chinese costumes can be presented.