고성능 표면침투제가 도포된 콘크리트의 복합열화저항성 평가

유성원(Yoo, Sung Won),서정인(Suh, Jeong In),하헌재(Ha, Hyun Jae),이상민(Lee, Sang Min),박상순(Park, Sang Sun) 한국콘크리트학회 2004 한국콘크리트학회 학술대회 논문집 Vol.2004 No.11

건설안전분야 : 가열방법을 이용한 고품질 순환골재 제조를 위한 실험적 연구

유성원 ( Sung Won Yoo ),민경완 ( Gyeong Oan Min ),허윤 ( Yoon Her ),하헌재 ( Heon Jae Ha ),문재흠 ( Jae Heum Moon ) 한국안전학회(구 한국산업안전학회) 2011 한국안전학회지 Vol.26 No.5

The use of waste concrete can resolve the environmental pollution and shortage of natural aggregate. However, recycled aggregate includes substantial amount of cement paste. So, these aggregates are more porous, and less resistant to mechanical actions than natural aggregates. So, recently, the new manufacture processes of high quality recycled aggregates were suggested such as heating and solving to acid liquid. But the method of solving to acid liquid is not economical and produces additional environmental pollution. In this paper, for the purpose of manufacture of high quality recycled aggregates, the heating processes was added to the existing process of recycled aggregates. To find the optimum process, the experiment was performed by using the method of statistical experiment design, and the heating temperatures(4 levels: 300, 450, 600 and 750℃) and heating times(4 levels: 5, 20, 40, 60 minute) were main experimental variables. By the test results, the optimum manufacturing condition of coarse recycled aggregate was 600℃ and 40 minute, and for the fine recycled aggregate, a little heating made a satisfaction to the KS standard quality code.

고성능 표면침투제가 도포된 콘크리트의 물리특성

유성원(Yoo, Sung Won),서정인(Suh, Jeong In),하헌재(Ha, Hyun Jae),이상민(Lee, Sang Min),이상근(Lee, Sang Guen) 한국콘크리트학회 2004 한국콘크리트학회 학술대회 논문집 Vol.2004 No.11

극단화 사고의 전환을 위한 세계시민교육 수업 모듈 개발

하승천(Ha, Seung Cheon),유성상(Yoo, Sung-Sang) 한국국제이해교육학회 2021 국제이해교육연구 Vol.16 No.3

본 연구에서는 세계시민교육 실천을 목적으로 극단화 사고의 전환 가능성을 위한 수업 전략을 모색하고, 이에 따른 수업 모듈 예시를 개발하였다. 사회나 학교 현장에서 발생하는 극단화 사고의 특성을 반영하고 이를 유연화하는 수업 전략을 수립하기 위해 세계시민교육 영역 9개 주제로부터 8개 핵심 내용을 추출, 8개 핵심 내용으로부터 수업 모듈의 핵심 개념인 극단화 사고, 사고 전환, 극복 실천을 설계하였다. 본 연구에서의 수업 모듈을 통해, 첫째, 기존의 세계시민성과 실질적 수업 내용 및 형태의 괴리를 극복하고, 사회와 학생 행위 사이에의 논리적 간극을 줄일 수 있을 것이다. 둘째, 지식으로서 존재하는 세계시민성이 실재가 됨으로써 실질적인 세계시민성을 체득할 수 있을 것이다. 셋째, 본 수업 모듈을 통해 체득된 세계시민성은 학생들의 실천적 규범, 실제적 지식 및 이론을 제공할 수 있을 것이다. In this study, as a part of global citizenship education, an educational strategy was sought for the possibility of shifting extreme thinking and an example of module was developed based on this. In order to establish the lesson strategy that reflects the characteristics of extreme thinking that occurs in society as well as schools and makes it flexible, 8 core contents are extracted from 9 topics in the field of global citizenship education. The core concepts of the lesson module from 8 core contents were polarization thinking, shifting thinking, and practice overcoming them. Through the education instructional module in this study, first, it will be possible to overcome the gap between existing global citizenship and actual lesson content and form, and to reduce the logical gap between society and student behavior. Second, global citizenship, which exists as knowledge, will become a reality, so that ‘real’ global citizenship can be acquired. Third, the global citizenship acquired through this module will provide practical norms, knowledge, and theory applicable in practical situations for students.

가설검증 방식을 통한 UWB Rake 수신기의 기준신호 선택 기법

이준용,유성열,윤성준,하동헌,Lee Joon-Yong,Yoo Sungyul,Yoon Sung-Jun,Ha Dong-Heon 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.2c

초광대역(UWB) 통신시스템의 응용 시나리오는 많은 경우 비가시적(non-LoS) 환경에서의 응용을 가정하고 있다. UWB 신호가 매질을 투과하여 방사될 경우 신호의 왜곡현상이 발생하며, 이는 수신부 상관기의 기준신호와 수신된 신호와의 상관계수를 감소시켜 성능을 저하시키는 요인이 된다. 본 논문에서는 가설검증 방식을 이용한 UWB Rake 수신기의 기준신호 선택 기법을 소개한다. 가설을 세우기 위한 파형의 선택을 위해 벡터 양자화 기법인 Linde-Buzo-Gray(LBG) 알고리듬을 사용하였다. 개시된 알고리듬을 성능을 non-LoS 환경에서 측정된 데이터를 이용해 평가하였다. Many application scenarios of ultra-wideband(UWB) radio assume non-line-of-sigit(non-LoS) signal propagations. Through-material propagation of UWB signal introduces a distortion of the waveform as well as attenuation, which will introduce a decrease of the correlation coefficient between the correlator template and the received signal. A hypothesis test approach to selection of the template waveform for UWB rake receivers is posed. Linde-Buzo-Gray(LBG) algorithm is used to select the candidate waveforms which are used to setup the hypothesis test. The performance of the algorithm is tested using a set of indoor non-LoS propagation measurement data.

TiO₂/Epoxy 나노복합재의 발열 특성에 관한 연구

안석환(Seok-Hwan Ahn),하유성(Yoo-Sung Ha),문창권(Chang-Kwon Moon) 한국해양공학회 2013 韓國海洋工學會誌 Vol.27 No.5

Recently, various nanoparticles have been used filler in polymer matrices. The particles of nano size are whether high or not cross-link density in polymer affects the thermal and mechanical properties of one. The properties change as a result of chemical reactions between the nanoparticles and the surface of the polymer. There are two models for nanocomposites: "repulsive interaction" and "attractive interaction" between the nanoparticles and matrix. In this study, the variation in the curing mechanism was examined when nano-size TiO₂ was dispersed into an epoxy (Bisphendol A, YD-128) with different curing agents. The results of this study showed that the exothermic temperature and Tg in the case of the nanoparticles used (Jeffamine) (D-180) at room temperature were reduced by an increase in the TiO₂ contents because of the "repulsive interaction" between the nanoparticles and the matrix. The tensile strengths were increased by increasing amounts of TiO₂ until 3 wt% because of a dispersion strengthening effect caused by the nanoparticles, because of the repulsive interaction. However, such tensile properties decreased at 5 wt% of TiO₂ because the TiO₂ was agglomerated in the epoxy. In contrast, in the case of the nanoparticles that used NMA and BDMA, the exothermic temperature and Tg tended to rise with increasing amounts of TiO₂ as a result of the "attractive interaction". This was because the same amounts of TiO₂ were well dispersed in the epoxy. The tensile strength decreased with an increase in the TiO₂ contents. In the general attractive interaction model, however, the cross-link density was higher, and tensile strength tended to increase. Therefore, for the nanoparticles that used NMA, it was difficult to conclude that the result was caused by the "attractive model."

탄소섬유를 이용한 Polyethylene배관의 전기융착 기술

안석환(Seok-Hwan Ahn),하유성(Yoo-Sung Ha),문창권(Chang-Kwon Moon) 한국해양공학회 2013 韓國海洋工學會誌 Vol.27 No.5

Fuel gas is an important energy source that is being increasingly used because of the convenience and clean energy provided. Natural gas is supplied to consumers safely through an underground gas pipe network made of a polyethylene material. In electrofusion, which is one of the joining methods used, copper wire is used as the heating wire. However, it takes a long time for fusion to occur because the electrical resistance of copper is low. In this study, therefore, electrofusion was conducted by replacing the copper heating wire with carbon fiber to reduce the fusion time and improve the production when joining large pipes. Fusion and tensile tests were performed after the electrofusion joint was made in the polyethylene pipe using carbon fiber. The results showed that the fusion time was shorter and the temperature inside the pipe was higher with and increase in the current value. The ultimate tensile strength of specimens was higher than that of virgin polyethylene pipe, except for polyethylene pipes joined using a current of 0.8 A. The best fusion current value was 0.9 or 1.0 A because of the short fusion time and lack of transformation inside the pipe. Thus, it was shown that carbon fiber can be used to replace the copper heating wire.