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교육 시설 생활인프라 특성을 고려한 지역 프로파일링 연구 - 서울시 광진구 중심으로 -
강우석,이희정,Kang, Woo-Seok,Lee, Hee-Chung 한국교육시설학회 2019 敎育施設 Vol.26 No.5
This study has a purpose to profile local sectors into meaningful groups by using facilities rates of Social Overhead Capital(SOC) for daily life. Comparing SOC for daily life among the meaningful groups, the profiling and comparison results bring the comprehensive understanding about the educational facilities in local sectors. For the research purpose, this study utilized Latent Profile Analysis(LPA) by using variables such as population, road information, SOC for daily life, usage of land, possession of land, and appraised value of land from the 2018 Geographic Information System(GIS) dataset of Gwangjin-gu, where is one of the administrative district of Seoul City. Results showed that there are four latent groups of sectors among 904 local sectors(100 squared-meters sector per each) in Gwangjin-gu. By comparing the four latent groups by using LPA, the results diagnose each sector's status and help to improve the policy about educational facilities. Specifically, by using dataset for SOC of daily life, there are four groups of local sectors and each group has different features. Based on the different features of local sector groups, there can be improved management of educational facilities matching with each group's features.
강우석,고중혁,Kang, Woo-Seok,Koh, Jung-Hyuk 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.12
Energy problem has been issued in worldwide because fossil fuel has being almost exhausted. A lot of renewable energy have been received attention to replace the energy from fossil fuel. Among them, piezoelectric energy harvester is one of excellent candidates. In general, micro scaled small sized energy harvesters were usually based on the lithography process. However, these lithography process require complicated process and high cost. In this paper, a new process has been proposed for micro-scaled piezoelectric energy harvester. $0.2Pb(Mg_{1/3}Nb_{2/3})O_3-0.8Pb(Zr_{0.52}Ti_{0.48})O_3$ composition was used as piezoelectric material due to excellent piezoelectric properties and also can be easily prepared by mixed oxide method.
미분탄-암모니아 혼소 전산해석을 위한 암모니아의 글로벌 연소 반응모델 개발
강우석(Woosuk Kang),박종민(Jongmin Park),류창국(Changkook Ryu) 한국연소학회 2022 KOSCOSYMPOSIUM논문집 Vol.2022 No.11
For computational fluid dynamics (CFD) of NH₃ cofiring with pulverized coal, the detailed reaction mechanism of NH₃ is not applicable because of the simplifications employed on coal combustion involving numerous reactions of hydrocarbons and char. This study developed a global combustion mechanism of NH₃ for CFD applications to cofiring with coal based on an optimization algorithm. For an existing detailed reaction mechanism of NH₃, three representative reaction parameters were acquired for different temperatures (1500-1900 K) and equivalence ratios (0.9-1.4) using Chemkin-Pro: i) characteristics time for decrease in NH₃ concentration, ii) peak and final N₂O concentration, and iii) final NO concentration. Using the results as the reference data, the rate constants for five reactions involving only the major species were optimized by the gradient descent method. The global mechanism of NH₃ exhibited reasonable agreement with the detailed mechanism in terms of the reaction parameters for the entire reaction conditions. Further evaluation of the mechanism is required using actual cofiring tests.
디젤자동차용 SCR/DPF 촉매장치의 De-Nox 특성
강우석(Wooseok Kang),최병철(Byungchul Choi),김화남(Hwanam Kim) 한국자동차공학회 2012 한국자동차공학회 지부 학술대회 논문집 Vol.2012 No.5-2
Selective catalytic reduction(SCR) is expected to be used extensively de-NOx control for diesel vehicle. Recent diesel emission aftertreatment system was composed with DOC+DPF+SCR. The complexity of the aftertreatment system can be reduced further by a combined system of the DPF coated with SCR. The aim of the study is to simplify the aftertreatment system by an implement of the DPF coated with SCR which can obtain simultaneous NOx reduction and PM oxidation. Model gas reactor is used to evaluate performance of the catalysts. NOx and NH3 are analyzed by FTIR and PM oxidation tests were performed a thermogravimetric analyzer(TGA). The maximum NOx conversion was above 70% with Cu-ZSM5 DPF/SCR and Fe-ZSM5 DPF/SCR. NOx conversion was better Cu-ZSM5 DPF/SCR than Fe-ZSM5 DPF/SCR, because it is stronger acidity of acid site of the Cu-ZSM5 DPF/SCR. Both catalysts were not happened oxidation of PM, which oxidized only by a thermal oxidation.
대향류 석탄화력 보일러의 NOx 저감을 위한 다단 OFA 및 CH₄ lancing 성능 평가
강우석(Woosuk Kang),조현빈(Hyunbin Jo),류창국(Changkook Ryu),이종국(Jongwook Lee) 한국연소학회 2021 KOSCOSYMPOSIUM논문집 Vol.2021 No.5
This study evaluate the performance of multi-level overfire air (OFA) and CH₄ lancing on combustion and NOx reduction in an opposed wall-firing boiler. Computational fluid dynamics (CFD) incorporating advanced coal combustion models was applied to evaluate two design parameters while fixing total stoichiometric ratio (SR) at 1.15 and that for the burner zone at 0.89. First, the OFA was modified into two levels (OFA1 and OFA2) and the flow rate distribution between them was evaluated. Second, the amount of CH₄ injected at the burners was varied between 0% and 20% of thermal input partially replacing that of coal. For the reference case, the CFD results showed reasonable agreement with the design data in terms of heat distribution and NOx emission. The NOx emission was reduced by 9% when OFA2 was used alone, the peak gas temperature entering the heat exchanger zone decreased by 25 ℃. When the thermal input of CH₄ was 10%, the NOx emission was reduced by 22% and the peak gas temperature was decreased by 5 ℃. All cases showed satisfactory carbon conversion, except for the case with a thermal input of CH₄ at 20%. The results suggest that the introduction of multi-level OFA and CH₄ lancing can be effective measures for NOx reduction without deteriorating the boiler performance.
강우석(Wooseok Kang),최병철(Byungchul Choi),김화남(Hwanam Kim) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
As more stringent regulations of diesel emissions are enforced in many advanced countries, an aftertreatment system advances to a combination system with some kinds of catalysts, then the total volume of catalysts is increased. The aim of this study is to simplify aftertreatment system by implementation of SCR-coated diesel particulate filter(DPF) which can obtain simultaneous NOx reduction and PM oxidation. Model gas reactor is used to evaluate performance of the catalysts. NOx and NH3 are analyzed by FTIR and PM oxidation tests were performed Thermogravimetric Aanalyzer(TGA). The prepared Nb(30%) and Ce(70%) catalyst by impregnation method was loaded on DPF. The catalyst obtained simultaneous reduction of NOx and PM oxidation. NOx conversion was about 70% at 350~450℃ in flow channel DPF coated with NbCe. PM oxidation improved compared to the Cu-ZSM5 catalyst.
디젤자동차용 SCR/DPF 촉매의 열적·화학적 열화 특성
강우석(Wooseok Kang),최병철(Byungchul Choi) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
Recent diesel emission aftertreatment system was composed with DOC + DPF + SCR. The complexity of the afterteratment system can be reduced further by a combined system of the DPF coated with SCR. The aim of the study is to simplify the aftertreatment by an implement of the DPF coated with SCR which can obtain simultaneous NOx reduction and PM oxidation. Futher, NOx conversion of DPF coated with SCR after hydrothermal and chemical aging was conducted to know thermal and chemical aging characteristics. Model gas reactor is used to evaluate performance of the catalyst. NOx and NH3 are analyzed by FTIR. As a result of experiment, The activity of the SCR/DPF catalysts after hydrothermal and chemical aging were more superior to the Cu-ZSM-5 based catalyst compare to the CuNb-ZSM-5 based catalyst in which is added Nb precursor in order to do PM oxidation reaction actively.
CO 포함 방산 배가스의 연소효율 향상을 위한 수치해석 연구
강우석(Woosuk Kang),조현빈(Hyunbin Jo),김태영(Taeyoung Kim),조한창(Hanchang Jo),류창국(Changkook Ryu) 한국연소학회 2020 KOSCOSYMPOSIUM논문집 Vol.2020 No.9
Some off-gases from a steel making process contains high concentration of CO which requires to be removed by oxidation at the flare stack. One way to achieve this is to install oxy-combustion gas burner at the shield of the flare stack for ignition of the off-gas. Using computational fluid dynamics (CFD), this study investigates the influences of design and operation parameters for the flare stack including different levels of CO concentration in the off-gas, tilting and yawing of four oxy-combustion gas burners, wind speed, pre-mixing of natural gas. The off-gas was difficult to maintain the flame because of its low energy content and excessive cooling by large volume of entrained air despite the use of oxy-combustion burner for heat-up and ignition. The flame was maintained only when the CO concentration in the off-gas was over 25% at the quiescent air condition, which achieved 99.7% of CO removal. Adjusting the burner angle was helpful in increasing CO oxidation inside the shield but was not successful in keeping the flame above. Pre-mixing natural gas inside the stack also increased the level of CO oxidation but has a cost issue. The optimal condition for near-complete CO oxidation were determined from the combustion efficiency and safety of the flare stack.