비정질 붕소강 섬유를 혼입한 콘크리트의 역학적 성능 및 중성자 차폐성능 평가

이준철 ( Lee Jun Cheol ),김화중 ( Kim Wha Jung ) 한국건축시공학회 2017 한국건축시공학회지 Vol.17 No.1

본 연구에서 비정질 붕소강 섬유를 혼입한 콘크리트의 역학적 성능 및 중성자 차폐성능을 평가하였다. 비정질 붕소강 섬유를 콘크리트 체적 대비 0.25%에서 1.0%까지 혼입하여 굳지 않은 콘크리트의 공기량과 슬럼프값, 경화된 콘크리트의 압축강도, 휨강도, 휨인성 및 중성자 차폐성능을 평가하였다. 실험결과, 비정질 붕소강 섬유의 혼입량이 증가할수록 콘크리트의 휨인성 및 중성자 차폐성능이 향상되는 것으로 나타났다. 이를 통해 비정질 붕소강 섬유의 혼입이 중성자차폐성능 뿐만 아니라 역학적 성능을 효과적으로 개선시켜줄 것이라고 기대된다. Mechanical properties and neutron shielding performance of concrete with amorphous boron steel fiber have been investigated in this study. The measurement of this investigation includes air contents, slump loss, compressive strength, flexural strength, flexural toughness and neutron shielding rate. Four different fiber volume fractions were selected ranging from 0.25% to 1.0% by volume for the amorphous boron steel fibers. The testing results showed that the flexural toughness and the neutron shielding rate were increase with the increase of volume fraction for amorphous boron steel fiber. Based on the result, it is concluded that the concrete with the amorphous boron steel fiber can be effectively applied to shield the neutron and to improve mechanical properties.

이종접합 나노 광촉매를 이용한 시멘트 모르타르의 물성 평가

이준철 ( Lee Jun-cheol ) 한국건축시공학회 2022 한국건축시공학회 학술발표대회 논문집 Vol.22 No.2

The properties of cement mortar with nano-heterojunction photocatalysts were investigated in this study. The following tests were conducted with the cement mortar : (1) Flow test of fresh cement mortar, (2) compressive strength and (3) acetaldehyde removal efficiency under visible light. Results indicated that the cement mortar with nano-heterojunction photocatalysts showed higher compressive strength and higher acetaldehyde removal efficiency as the mixing ratio of nano-heterojunction increased.

생물학적 CO2 전환기술 Hydrogenotrophic methanogen을 이용한 이산화탄소의 메탄 전환

이준철 ( Jun Cheol Lee ),김재형 ( Jae Hyung Kim ),박대원 ( Dae Won Pak ),이원권 ( Won Kwon Lee ) 한국공업화학회 2009 공업화학전망 Vol.12 No.5

시멘트 페이스트의 압축강도에 있어서 미생물의 영향

이준철(Lee, Jun-Cheol),김화중(Kim, Wha-Jung),천우영(Chun, Woo-Yong),이창준(Lee, Chang-Joon) 대한건축학회 2013 大韓建築學會論文集 : 構造系 Vol.29 No.7

This study investigated the effect of microorganisms on compressive strength development of cement paste. The Sporosarcina pasteurii used in this study was capable of microbial induced calcite precipitation(MICP). Four different cell concentrations were selected ranging from 10 to 10? per ml. distilled water as mixing water. From experimental results, cement paste with microorganisms showed higher strength gain compared with reference cement paste at earlier ages. From TG/DSC analysis, more calcium hydroxide was observed in the cement paste with microorganisms. The degree of hydration of the cement paste with microorganisms, evaluated by measuring non-evaporable water contents in cement paste, was also higher than that of reference cement paste. It is very likely that the strength improvement of cement paste is due to acceleration of hydration process caused by the metabolism of microorganisms. Further investigation is in progress to identify the specific mechanisms which is responsible for the improvement of compressive strength in early ages.

긴급 상황 시나리오 해석을 위한 독립 객체의 규칙 기반 및 확률적 이벤트 인식

이준철(Jun-Cheol Lee),최창규(Chang-Gyu Choi) 한국멀티미디어학회 2008 멀티미디어학회논문지 Vol.11 No.3

자동차 배기계의 배기압 감응형 제어 머플러 개발(1) - 배기계의 일반 특성과 제어 밸브의 특성-

이해철(Haechul Lee),이준서(Joonseo Lee),윤준규(Junkyu Yoon),차경옥(Kyungok Cha) 한국자동차공학회 2001 한국 자동차공학회논문집 Vol.9 No.1

부동산 유형별 매매가격 변동의 상호관계에 관한 실증연구 : 서울시 권역별 비교를 중심으로

이준철(Lee, Jun Chul),김재태(Kim, Jae Tae) 한국주거환경학회 2020 주거환경(한국주거환경학회논문집) Vol.18 No.3

본 연구는 주택시장을 이해하기 위한 시계열적 연구에 있어 다른 부동산 유형과의 관계 속에서 주택시장의 변화 특성을 찾기 위한 목적으로 진행되었다. 이를 위해 부동산 유형별 종류 및 특성, 서울시 권역별 부동산 유형별 특성, 주택하위시장 이론 및 관련 선행연구를 고찰하여 연구의 차별성 및 연구의 방향성을 찾았다. 분석자료는 부동산 114Reps의 데이터를 활용하여 서울시 4개 권역별로 아파트, 오피스텔, 집합상가에 대한 2006년 1분기~2019년 2분기까지 매매가격에 대한 시계열데이터를 구축한 뒤 지수화하여 실증분석을 진행하였다. 본 연구에 나타난 부동산 유형별 가격 간의 상관관계에 대한 실증분석의 주요 결과는 다음과 같다. 첫째, 부동산 유형별 가격 간 인과관계는 권역별 특성에 따라 원인변수와 결과변수에 차이가 존재하였다. 둘째, 부동산 유형별 가격 간 상관관계에 있어 권역별 특성에 따라 정(+)과 부(-) 관계가 나타났다. 셋째, 부동산 유형별 가격 간 영향관계에 있어 아파트, 오피스텔, 집합상가의 단기간 내 상호 영향력은 크지 않은 것으로 나타났다. 실증분석 결과, 부동산 유형별 가격 간 상호관계에 있어서 권역별 시장 상황 및 특성에 따라 인과관계 및 상관관계에 차이가 있음과 투자수요의 움직임에 따라 부동산 유형별 가격 변동에 대한 영향관계가 다르게 나타날 수 있음을 확인하였다. This study was conducted with the aim of finding the characteristics of changes in the housing market in relation to other types of real estate in a time series study to understand the housing market. To this end, we looked into the types and characteristics of each type of real estate, the characteristics of each type of real estate in Seoul, the housing sub-market theory, and related prior research to find the differentiation of research and direction of research. Using the data of real estate 114Reps, time series data on selling prices were established between Q1 2006 and Q2019 for apartment, officetels, and collective commercial stores in each of the four districts of Seoul, and the empirical analysis was conducted by indexing them. The main results of the empirical analysis of the interrelationships between prices by type of real estate shown in this study are as follows : First, the causal relationship between prices by type of real estate was different in cause and effect variables depending on regional characteristics. Second, in terms of correlation between prices by type of real estate, positive (+) and negative (-) relationships were shown depending on regional characteristics. Third, it was found that the mutual influence of apartments, officetels, and collective commercial stores in the short term was not significant in terms of the impact relationship between prices by type of real estate. The empirical analysis results confirmed that there are differences in causality and correlation between prices by type of real estate depending on the market situation and characteristics of each region, and meaningful research results were derived that confirmed that the impact of price changes by type of real estate may vary depending on the movement of investment demand.

전기화학적 방법의 TRC(Total residual chlorine) 측정 연구(II: Pt전극 이용)

이준철 ( Jun Cheol Lee ),박대원 ( Dae Won Park ) 한국물환경학회 2014 한국물환경학회지 Vol.30 No.3

The conventional methods for total residual chlorine such as iodometry and DPD colorimetric can cause secondary pollution due to additional agents, also have a wide error range. As for alternative, electrochemical method can measure TRC(Total residual chlorine), and is not required as additional agents, also very suitable for using the fields of ballast water because test time is relatively fast. Therefore, this study was investigated for changing charge by agitation, salt concentration, and temperature change. Charge showed differences based on changes of reduction peak with or without agitation. In contrast, TRC and charge were well correlated in constant agitation speed. As TRC and charge were analyzed with high correlations in constant salinity and temperature of ocean, thereby conductivity was firstly measured, and charge had high correlation for TRC in spite of changing salinity and temperature Pt electrode revealed high reliability (r2 = 0.960) because it was rarely effected by TRC, On the other hand, Au electrode appeared inadequate (r2 = 0.767) to use sensor in less than 1.0 ppm of TRC. For high accuracy and detection of TRC, Pt and Au electrodes for test time were, respectively, 14 and 22 seconds. As a result, Pt electrode was more valuable than Au electrode in terms of response time.

바이오 수소를 이용한 이산화탄소의 메탄 전환 연구

이준철(Jun Cheol Lee),김재형(Jae Hyung Kim),최광근(Kwang Keun Choi),박대원(Dae Won Pak) 大韓環境工學會 2008 대한환경공학회지 Vol.30 No.9

유기성 폐기물을 이용하여 생산된 수소를 환원제로 활용하여 이산화탄소를 유용한 에너지원인 메탄으로 전환시키고자 하였다. 3개월 동안 혐기성 미생물을 이산화탄소와 수소만을 이용하여 배양하였으며, 그 결과 acetogenotrophs의 영향에 의한 메탄의 생성은 없었고, 이산화탄소를 8 mL/min으로 주입하였을 때 이산화탄소와 수소의 주입비가 1:5에서 메탄의 생성량이 2.2 m3/m3day로 가장 많았으며, 이때의 이산환탄소 저감률 또한 92%로 가장 우수하였다. 회분형태로 수소 생산과 메탄발효조와의 연계실험을 통하여, 연속적으로 수소를 생산하면서 이산화탄소를 같이 메탄발효조에 주입하여, 이산화탄소의 메탄으로의 전환을 확인하였다. In the present study, carbon dioxide was converted to methane, using bio-hydrogen. Here, the bio-hydrogen was produced from organic waste. The anaerobic microorganism was cultured using only carbon dioxide and hydrogen for duration of 3 months. Therefore methane was not produced with acetogenotrophs. During methane production, carbon dioxide and hydrogen are taken in different ratios; among which 1:5 ratio has shown the highest methane yield. Carbon dioxide and hydrogen were introduced into the reactor at the rate of 8 mL/min and 40 mL/min, respectively. In this case, 92% of carbon dioxide was reduced and 2.2 m3/m3 day amount of methane was produced. Thus, the process has been successful in conversion of carbon dioxide into methane by purging it into methane fermentation reactor with bio-hydrogen using batch process.

Ru 코팅량에 따른 RuO₂/Ti 전극의 염소 발생

이준철(Jun Cheol Lee),박대원(Dae Won Pak) 大韓環境工學會 2012 대한환경공학회지 Vol.34 No.11

단위면적당(cm2) 루테늄의 코팅량이 1.5 mg, 2.5 mg, 3.5 mg, 5.5 mg, 8.5 mg의 RuO₂/Ti 전극을 제조하여 코팅량에 따른 전기화학적 특성 차이와 염소 발생에 미치는 영향을 조사하였다. 순환전압 실험 결과 루테늄이 코팅된 전극의 염소 발생 과전압은 약 1.15 V (vs. Ag/AgCl)로 거의 일정하였다. 그러나 교류 임피던스 분광법, 동전위분극실험 결과 단위면적당(cm2) 루테늄의 코팅량이 2.5 mg, 3.5 mg RuO₂/Ti 전극의 저항은 각각 0.4582 Ω, 0.5267 Ω, 부식속도는 각각 0.082 mm/yr, 0.058 mm/yr로 내구성이 가장 우수하였다. 염소 발생량은 단위면적당(cm2) 루테늄의 코팅량 3.5 mg 전극이 15.2 mg/L로 가장 높게 측정되었다. We investigated the effects of electrochemical characteristics and generation of chlorine by the different amount of Ru coating which was prepared for RuO₂/Ti electrode coated with 1.5 mg, 2.5 mg, 5.5 mg, 8.5 mg Ru per unit area (cm2). As a Result of the cycle voltammetry experiments, chlorine overvoltage of Ru-coated electrodes showed to be the nearly sustained value of approximately 1.15V (vs. Ag/AgCl). By contrary, According to the results of the AC impedance spectroscopy and potentiodynamic polarization tests, the amount of Ru per unit area (cm2) included 2.5 mg, 3.5 mg as RuO₂/Ti offered the highest levels of durability which was electrode resistance and corrosion rate appeared to be 0.4582 Ω, 0.5267 Ω and 0.082 mm/yr, 0.058 mm/yr, respectively. It was also observed that generation of chlorine coated with 3.5 mg per unit area (cm2) was the highest value of 15.2 mg/L.