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On the origin of reactive Pdcatalysts for an electrooxidation of formic acid
Jeon, Hongrae,Uhm, Sunghyun,Jeong, Beomgyun,Lee, Jaeyoung The Royal Society of Chemistry 2011 Physical chemistry chemical physics Vol.13 No.13
<P>We investigated the origin of the reactive surface of Pdcatalysts during the electrocatalytic oxidation of formic acid. XPS analysis was the primary tool adapted to characterize the surface changes in Pdcatalysts arising from interactions with formic acid. Pdcatalysts showed fast deactivation, though their activity could be simply recovered by applying a reduction potential at which hydrogen evolution reaction can occur. XPS analysis revealed that the surface of Pdcatalysts is significantly affected by interaction with formic acid, thus confirming that the surface coverage of oxygen species plays an important role in formic acid electrooxidation on the Pdcatalysts. At the same time, mass transfer of formic acid also has an effect on the deactivation of Pdcatalysts.</P> <P>Graphic Abstract</P><P>Coverage ratio change of Pd surface species and self-reactivation of Pd catalysts in an electrooxidation of formic acid. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0cp02863k'> </P>
Reduced optical loss and electrode design in bifacial PERC solar cells
Hongrae Kim,Somin Park,Youngwoo Jeon,Minkyu Jang,Donghyun Oh,Junsin Yi,Jinjoo Park 한국진공학회 2021 한국진공학회 학술발표회초록집 Vol.2021 No.2
This study conducted with the aim of 'high efficiency PERC(passivated emitter and rear contact) solar cells'. STC conditions were all applied in here and M2 size wafer was used. We got the optical properties on 5 busbars 0.6 mm width and 100 fingers with 30 µm. Next, we fixed the optimized properties of the front side and changed the rear side designs. As a result, compared to mono-facial PERC solar cell, we got 25.66% from bifacial type. Overall 19.44% of efficiency and 18.13% of Jsc was gained.
김홍래(Hongrae Kim),전병일(Byung-Il Jeon),이나래(Narae Lee),최성동(Seong-Dong Choi),장영근(Young-Keun Chang) 한국항공우주학회 2014 韓國航空宇宙學會誌 Vol.42 No.2
무인항공기(UAV)를 이용하여 효율적인 감시정찰을 수행하기 위해서는 센서의 고성능, 다중화와 함께 운용상황에 맞는 최적화된 비행경로계획이 요구된다. 이뿐만 아니라 시스템 개발 또는 임무운용 전 임무 효용성 평가, 평시와 전시에 빠른 작전 결정을 위해서는 임무를 가시화할 수 있는 가시화 도구가 필요하다. 본 연구에서는 STK(Systems Tool Kit)와 MATLAB을 통합한 임무 가시화 및 분석 도구를 개발하고 이를 통하여 UAV 감시정보정찰(ISR; Intelligence, Surveillance and Reconnaissance) 임무분석을 수행하였다. 개발된 임무분석 도구에는 비행최적화 뿐만 아니라 장애물 회피 알고리즘, FoM(Figure of Merit) 분석 알고리즘이 적용되어 최적의 임무계획이 가능하도록 하였다. The optimized flight path planning which is appropriate for UAV operation with high performance and multiplex sensors is required for efficient ISR missions. Furthermore, a mission visualization tool is necessary for the assessment of MoE(Measures of Effectiveness) prior to mission operation and the urgent tactical decision in peace time and wartime. A mission visualization and analysis tool was developed by combining STK and MATLAB, whose tool was used for UAV ISR mission analyses in this study. In this mission analysis tool, obstacle avoidance and FoM(Figure of Merit) analysis algorithms were applied to enable the optimized mission planning.
An, Junyeong,Jeon, Hongrae,Lee, Jaeyoung,Chang, In Seop American Chemical Society 2011 Environmental science & technology Vol.45 No.12
<P>Organic contamination of water bodies in which benthic microbial fuel cells (benthic MFCs) are installed, and organic crossover from the anode to the cathode of membraneless MFCs, is a factor causing oxygen depletion and substrate loss in the cathode due to the growth of heterotrophic aerobic bacteria. This study examines the possible use of silver nanoparticles (AgNPs) as a cathodic catalyst for MFCs suffering from organic contamination and oxygen depletion. Four treated cathodes (AgNPs-coated, Pt/C-coated, Pt/C+AgNPs-coated, and plain graphite cathodes) were prepared and tested under high levels of organics loading. During operation (fed with 50 mM acetate), the AgNPs-coated system showed the highest DO concentration (0.8 mg/L) in the cathode area as well as the highest current (ranging from 0.04 to 0.12 mA). Based on these results, we concluded that (1) the growth of oxygen-consuming heterotrophic microbes could be inhibited by AgNPs, (2) the function of AgNPs as a bacterial growth inhibitor resulted in a greater increase of DO concentration in the cathode than the other tested cathode systems, (3) AgNPs could be applied as a cathode catalyst for oxygen reduction, and as a result (4) the MFC with the AgNPs-coated cathode led to the highest current generation among the tested MFCs.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2011/esthag.2011.45.issue-12/es2000326/production/images/medium/es-2011-000326_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es2000326'>ACS Electronic Supporting Info</A></P>
전재원(Jaewon Jeon),정희윤(Heeyun Jeong),김병호(Byoung-Ho Kim),김홍래(Hongrae Kim) 대한전기학회 2021 전기학회논문지 Vol.70 No.5
Since state estimation is a real-time application program, its computational speed is important as well as accuracy. Therefore, improving the computation speed of state estimation is a very significant issue. This paper studied the method of improving computational speed of state estimation by using the parallel computing technique. In order to apply the parallel computing technique to state estimation, OpenMP was used as a programming tool. This tool is a shared memory programming model that requires no other devices such as GPU(graphics processing unit) and DSP(digital signal processor), and has the advantage of the fastest data transfer rate between memories. This paper proposes an algorithm that divides the entire system into small scales and performs state estimation in parallel with the divided systems. The proposed algorithm can improve the speed of computing state estimation and also the performance of the bad data processing that may happen for some reasons.
Jeong, Beomgyun,Jeon, Hongrae,Toyoshima, Ryo,Crumlin, Ethan J.,Kondoh, Hiroshi,Mun, Bongjin Simon,Lee, Jaeyoung American Chemical Society 2018 The Journal of Physical Chemistry Part C Vol.122 No.4
<P>While model studies of surface science under ultrahigh vacuum (UHV) have made significant contributions to understanding electrochemistry, many issues related to electrochemical phenomena still remain unanswered due to the extreme environmental differences between UHV and liquid conditions. Electrochemical formic acid (HCOOH) oxidation is one such example. While the dehydration step in the indirect oxidation pathway (HCOOH → H<SUB>2</SUB>O + CO<SUB>ad</SUB> → 2H<SUP>+</SUP> + 2e<SUP>–</SUP> + CO<SUB>2</SUB>) is observed in the electrochemical oxidation of formic acid on Pt(111) surface, the surface science studies conducted in UHV condition reported the complete HCOOH dissociation to H<SUB>2</SUB> and CO<SUB>2</SUB> on Pt(111) surface with no adsorbed CO at room temperature. A dehydration mechanism may also exist in gas-phase HCOOH dissociation in some conditions different from UHV, but it has not been demonstrated with a surface science method due to pressure limitations. Using ambient pressure X-ray photoelectron spectroscopy (AP-XPS), we observed the dehydration mechanism of gas-phase HCOOH in unprecedented high pressure environment for the first time. This study is a demonstration of reconciling the disagreement between electrocatalysis and surface science by bridging the environment gap.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2018/jpccck.2018.122.issue-4/acs.jpcc.7b07735/production/images/medium/jp-2017-077355_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp7b07735'>ACS Electronic Supporting Info</A></P>