Exsolution of Various Nanoparticle Catalysts in Layered Perovskite Anode for Solid Oxide Fuel Cells

Guntae Kim(김건태) 한국가스학회 2017 한국가스학회 학술대회논문집 Vol.2017 No.5

Application of micellar enhanced ultrafiltration and activated carbon fiber hybrid processes for lead removal from an aqueous solution

Guntae Son,이승환 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.3

Micellar enhanced ultrafiltration (MEUF) and activated carbon fiber (ACF) hybrid processes were used to investigate the removal condition of lead ions and surfactant sodium dodecyl sulfate (SDS) from an aqueous solution. Lead removal efficiency increased with the increase of initial surfactant concentration. Molar ratio of lead to SDS up to 1 : 5 has shown over 90% removal efficiency of lead, and the optimum molar ratio of lead to SDS was found to be 1 : 5. Lead removal efficiency increased with the increase of pH, while it was maintained below 30% without surfactant. Lead removal was mainly due to the adsorption mechanism and no secondary layer was formed to reduce the flux. Lower molecular weight cut-off (MWCO) membrane has shown higher removal efficiency than higher MWCO one. Permeate flux decreased with the increase of molar ratio of lead to SDS. Flux decline was mainly due to the accumulation of micelles on the membrane surface. The presence of copper as a co-existing heavy metal highly affected the lead removal while nickel did not. Two sets of ACF unit in series were able to remove SDS surfactant effectively from the effluents of MEUF process.

Synchronized methylene blue removal using Fenton-like reaction induced by phosphorous oxoanion and submerged plasma irradiation process

Son, Guntae,Kim, Do-hyung,Lee, Jung Seok,Kim, Hyoung-il,Lee, Changha,Kim, Sang-Ryoung,Lee, Hongshin Academic Press 2018 Journal of Environmental Management Vol. No.

<P><B>Abstract</B></P> <P>In this study, a combination of phosphorus (PP) oxoanions in a submerged plasma irradiation (SPI) system was used to enhance the removal efficiency of dyes from wastewater. The SPI system showed synergistic methylene blue removal efficiency, due to the plasma irradiation and Fenton-like oxidation. The ferrous ions released from the iron electrode in the SPI system under plasmonic conditions form complexes with the PP anions, which can then react with dissolved oxygen (O<SUB>2</SUB>) or hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) via Fenton-like reactions. The experimental results revealed that a sodium triphosphate (TPP) combined SPI system has a higher dye removal efficiency than a tetrasodium pyrophosphate (DP) or a sodium hexametaphosphate (HMP) combined SPI system under similar dissolved iron ion concentrations. To confirm the accuracy of the proposed removal mechanism via Fenton-like oxidation, it was compared to SPI systems under an oxygen environment (TPP/SPI/O<SUB>2</SUB> (<I>k</I> = 0.0182 s<SUP>−1</SUP>)) and a nitrogen environment (TPP/SPI/N<SUB>2</SUB> (<I>k</I> = 0.0062 s<SUP>−1</SUP>)). The results indicate that the hydroxyl radical (OH) in the TPP/SPI/O<SUB>2</SUB> system is the major oxidant in methylene blue removal, because the dye degradation rates dramatically decreased with the addition of radical scavengers such as <I>tert</I>-butanol (<I>k</I> = 0.0023 s<SUP>−1</SUP>) and methanol (<I>k</I> = 0.0021 s<SUP>−1</SUP>). On the other hand, no change was observed in the methylene blue removal efficiency of the TPP/SPI/O<SUB>2</SUB> system when it was subjected to a wide range of pHs (3–9). In addition, it was proved that this system could be used to eliminate six different commercial dyes. The results of this study indicated that the TPP/SPI/O<SUB>2</SUB> system is a promising advanced oxidation approach for dye wastewater treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The iron electrode based SPI with phosphorous oxoanion is effective for methylene blue removal in water. </LI> <LI> The hydroxyl radical or ferryl ions are responsible for the methylene blue degradation. </LI> <LI> Reactive oxidant species are formed by the primary plasma irradiation and the secondary Fenton-like reaction. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

감시 영상에서의 장면 분석을 통한 이상행위 검출

배건태(Guntae Bae),어영정(Youngjung Uh),곽수영(Sooyeong Kwak),변혜란(Hyeran Byun) 한국통신학회 2011 韓國通信學會論文誌 Vol.36 No.12

화상 통신에서의 사생활 보호를 위한 실시간 전경 분리 및 배경 대체

배건태(Guntae Bae),곽수영(Sooyeong Kwak),변혜란(Hyeran Byun) 한국통신학회 2009 韓國通信學會論文誌 Vol.34 No.5

탄소 중립-제로를 향한 H₂ 및 유용한 화학 물질 생산을 통한 고효율 금속-CO₂ 시스템

김건태(Guntae Kim),양예진(Yejin Yang),김정원(Jeongwon Kim),표세원(Sewon Pyo) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

대기 중 이산화탄소 (CO2)는 산업 기간 동안 278에서 415ppm으로 증가했으며 기후 변화에 중대한 영향을 미쳤습니다. 이러한 위기에 대응하여 탄소 포집, 활용 및 저장/격리 (CCUS) 기술이 연구되었습니다. 그러나 지금까지 기존 전환 기술의 경제성은 부진한 CO2 전환으로 인해 여전히 불충분합니다. 여기에서 우리는 전기 에너지와 수소 (H2)를 생성하기 위해 수용액에서 CO2의 자발적인 용해로 인한 산성도를 활용하는 수계 아연-, 알루미늄-및 마그네슘-CO2 시스템을 보고합니다. 이 시스템은 알칼리 및 중성 조건 하에서 전형적인 HER 와 비교하여 0.4V 만큼 양의 변화된 수소 발생 반응 (HER) 개시 전위를 가지며 34mV dec-의 낮은 Tafel 기울기로 HER 반응을 용이하게 합니다. Al-CO2 시스템의 최대 전력 밀도는 125mW cm^-2 로 CO2 활용 전기 화학 시스템 중 가장 높은 값입니다. 이론적으로는 10kW 규모의 금속 -CO2 시스템에서 10,000L (약 1kg H2)의 수소 (H2) 가스를 생산할 수 있고 각각 시간당 30kg의 CO2를 제거할 수 있습니다. Atmospheric carbon dioxide (CO2) has increased from 278 to 415 parts per million (ppm) over the industrial period and has critically impacted climate change. In response to this crisis, carbon capture, utilization, and storage/sequestration (CCUS) technologies have been studied. So far, however, the economic feasibility of the existing conversion technologies is still inadequate owing to sluggish CO2 conversion. Herein, we report an aqueous zinc–, aluminum–, and Mg-CO2 system that utilizes acidity from spontaneous dissolution of CO2 in aqueous solution to generate electrical energy and hydrogen (H2). The system has a positively shifted onset potential of hydrogen evolution reaction (HER) by 0.4 V compared to a typical HER under alkaline conditions and facile HER kinetics with low Tafel slope of 34 mV dec-1. The Al–CO2 system has a maximum power density of 125 mW cm^-2 which is the highest value among CO2 utilization electrochemical system. Theoretically, in 10 kW-scale metal-CO2 system, the 10,000 L (about 1 kg H2) of hydrogen (H2) gas could be produced and 30 kg of CO2 could be removed per hour, respectively.

Application of Advanced Submerged Plasma Irradiation Process for Treatment of Reverse Osmosis (RO) Concentrate Wastewater

Rahman Rafique,Guntae Son,Prajwal Shrestha,Sohan Shrestha,Jeyoen Moon,Seunghwan Lee 대한환경공학회 2013 대한환경공학회 학술발표논문집 Vol.2013 No.6

Moving-object segmentation using a foreground history map.

Kwak, Sooyeong,Bae, Guntae,Byun, Hyeran The Society 2010 Journal of the Optical Society of America. A, Opti Vol.27 No.2

<P>This paper describes a real-time foreground segmentation method in monocular video sequences for video teleconferencing. Background subtraction is widely used in foreground segmentation for static cameras. However, the results are usually not accurate enough for background substitution tasks. In this paper, we propose a novel strategy for fast and accurate foreground segmentation. The strategy consists of two steps: initial foreground segmentation and fine foreground segmentation. The key to our algorithm consists of two steps. In the first step, a moving object is roughly segmented using the background subtraction method. In order to update the initial foreground segmentation results in the second step, a region-based segmentation method and a foreground history map (FHM)-based segmentation representing the combination of temporal and spatial information were developed. The segmentation accuracy of the proposed algorithm was evaluated with respect to the ground truth, which was the manually cropped foreground. The experimental results showed that the proposed algorithm improved the accuracy of segmentation with respect to Horprasert's well-known algorithm.</P>

Electrochemical Properties of La₄Ni₃O₁₀-GDC Composite Cathode by Facile Sol-gel Method for IT-SOFCs

Choi, Sihyuk,Kim, Guntae The Korean Ceramic Society 2014 한국세라믹학회지 Vol.51 No.4

Among the Ruddlesden-Popper series, $La_4Ni_3O_{10}$ has received widespread attention as a promising cathode material by reason of its favorable properties for realizing high performance of intermediate temperature solid oxide fuel cells (IT-SOFCs). The $La_4Ni_3O_{10}$ cathode is prepared using the facile sol-gel method by employing tri-blockcopolymer (F127) to obtain a single phase in a short sintering time. There are no reactions between the $La_4Ni_3O_{10}$ cathode and the $Ce_{0.9}Gd_{0.1}O_{2-\delta}$ (GDC) electrolyte upon sintering at $1000^{\circ}C$, indicating that the $La_4Ni_3O_{10}$ cathode has good chemical compatibility with the GDC electrolyte. The maximum electrical conductivity of $La_4Ni_3O_{10}$ reaches approximately 240 S $cm^{-1}$ at $100^{\circ}C$ and gradually decreases with increasing temperaturein air atmosphere. The area specific resistance value of $La_4Ni_3O_{10}$ composite with 40 wt% GDC is $0.435{\Omega}cm^2$ at $700^{\circ}C$. These data allow us to propose that the $La_4Ni_3O_{10}$-GDC composite cathode is a good candidate for IT-SOFC applications.

블록 히스토그램 및 동적 매칭을 이용한 중복 동영상의 빠른 검출

임여선(YeoSun Lim),배건태(GunTae Bae),임광용(KwangYong Lim),어영정(YoungJung Uh),변혜란(Hyeran Byun) 한국정보과학회 2013 정보과학회논문지 : 소프트웨어 및 응용 Vol.40 No.2

다양한 IT 기술의 발전으로 동영상 데이터의 사용이 폭발적으로 증가하면서 중복 동영상 또한 증가하게 되었다. 원본 동영상에 여러 종류의 변환을 가하여 생성된 중복 동영상들은 저작권 침해 및 동영상 관리와 검색 시 정확도를 떨어뜨리고 작업 시간을 증가시키는 문제를 일으키고 있다. 이러한 문제를 해결하기 위하여 본 논문에서는 블록 히스토그램 기반의 특징 추출과 동적 매칭을 사용하여 빠르게 중복동영상을 검출하는 방법을 제안한다. 다양한 변환에 강인하도록 블록 단위로 시간적 히스토그램을 특징 벡터로 사용하였다. 본 논문에서 제안하는 방법의 성능을 평가하기 위하여 두 개의 동영상 데이터 집합을 사용하여 중복 동영상 검출, 중복 동영상 클러스터링, 속도 평가 등의 실험을 수행한 결과, 제안하는 방법이 기존의 방법들보다 우수한 정확도를 나타내고 매칭 작업에서 약 5배 빠른 속도로 처리되는 것을 확인하였다. The use of multimedia data is sharply increasing according to the development of various IT technologies. Especially as the use of video increases exponentially, the video copy causes lower accuracy and demands more time for video management and video search. In this paper, we proposed the real-time video copy detection based on block histogram and dynamic matching. We extracted block histogram as feature vector for the various transformations. Moreover, dynamic matching method for faster and more accurate video matching was suggested. Two video data sets were used to evaluate the proposed method and it showed higher performances than previous work. Specifically, the proposed dynamic matching method is 5 times faster working speed and excellent accuracy.