http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Kim, MinJoong,Kim, Sunghyun,Song, DongHoon,Oh, SeKwon,Chang, Kee Joo,Cho, EunAe Elsevier 2018 Applied catalysis. B, Environmental Vol.227 No.-
<P><B>Abstract</B></P> <P>Herein, we report a novel strategy to promote electrochemical oxygen evolution reaction (OER) on cobalt (Co) surface by coupling Co to molybdenum carbide (Mo<SUB>2</SUB>C). Chemically coupled Co and Mo<SUB>2</SUB>C nanoparticles were synthesized through a simple heat treatment of the mixture containing Co and Mo precursors and graphitic carbon nitride (g-C<SUB>3</SUB>N<SUB>4</SUB>). Transmission electron microscopy (TEM) images obviously showed that Co and Mo<SUB>2</SUB>C nanoparticles were coupled at Co/Mo<SUB>2</SUB>C interfaces. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation results revealed that electrons were transferred from Co to Mo<SUB>2</SUB>C nanoparticles across the interfaces. The electron transfer makes the Co surface more electrophilic by <I>d</I>-band center of Co upshift, leading to an increase in OH<SUP>−</SUP> affinity. As a result, the Co nanoparticles coupled with Mo<SUB>2</SUB>C have OER-favorable Co-oxo and Co-hydroxo configuration within their oxidized surfaces, and hence, can accelerate the overall OER than bare Co nanoparticles. This work demonstrates that the Co nanoparticles chemically coupled to Mo<SUB>2</SUB>C exhibited excellent OER activity and stability in an alkaline electrolyte and suggests a promising way to design an active OER catalyst.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A chemically coupled Co and Mo<SUB>2</SUB>C nanoparticles is designed for alkaline OER catalyst. </LI> <LI> Chemical coupling of Co and Mo<SUB>2</SUB>C leads to electron transfer from Co to Mo<SUB>2</SUB>C. </LI> <LI> This electron transfer makes Co surface more electrophilic by <I>d</I>-band center of Co upshift. </LI> <LI> Electrophilic Co surface leads to the formation of OER-active Co-oxo/hydroxo subunits. </LI> <LI> Therefore, the Co nanoparticles coupled to Mo<SUB>2</SUB>C exhibited high OER activity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Design of Mg-Cu alloys for fast hydrogen production, and its application to PEM fuel cell
Oh, SeKwon,Kim, HyoWon,Kim, MinJoong,Eom, KwangSup,Kyung, JoonSeok,Kim, DoHyang,Cho, EunAe,Kwon, HyukSang Elsevier 2018 Journal of Alloys and Compounds Vol.741 No.-
<P><B>Abstract</B></P> <P>Mg-Cu alloys are designed for fast hydrogen generation by precipitating an electrochemically noble phase (Mg<SUB>2</SUB>Cu) at the grain boundaries. The noble precipitates accelerate the hydrolysis kinetics of the alloy by synergetic action of galvanic and intergranular corrosion. The Mg-3Cu alloy exhibits a hydrogen generation rate of 5.23 ml min<SUP>−1</SUP> g<SUP>−1</SUP>, which is 307 times faster than that of pure Mg (0.017 ml min<SUP>−1</SUP> g<SUP>−1</SUP>). Furthermore, the effects of annealing of the alloy on the hydrogen generation rate and the feasibility of the production of power via hydrolysis of Mg-3Cu alloy are also confirmed. The annealing of the alloy reduces the hydrogen generation rate through the decrease of precipitates, and 10 g of Mg-3Cu alloy can produce power of 7.25 W for 37 min by operation of a single cell PEMFC.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mg-Cu (1∼3 wt %) alloys were specially designed for fast H<SUB>2</SUB> generation. </LI> <LI> Electrochemically noble phase (Mg<SUB>2</SUB>Cu) was precipitated along the grain boundary. </LI> <LI> H<SUB>2</SUB> generation rate of Mg-3Cu alloy was 307 times faster than that of pure Mg in seawater. </LI> <LI> Enhanced performance is originated from the galvanic, intergranular corrosion. </LI> <LI> Just 10g of Mg-3Cu alloy can produce 7.25 W for 37 min stably via PEMFC operation. </LI> </UL> </P>
SeKwon Oh,YoungJun Kim,MinYoung Shon,권혁상 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.5
In present study, we quantitatively define the galvanic corrosion phenomenon of Cu electrically coupled to Au on Print Circuit Board in Organic Solderability Preservatives (OSP) pretreatment (pickling and soft etching) solutions. As a result of polarization and ZRA test, galvanic corrosion rate of Cu in soft etching solution was about 3000 times higher than that of pickling solution. The oxone in OSP soft etching solution was acted as strong oxidant for Cu on PCB substrate. And the galvanic corrosion of Cu in OSP soft etching solution was examined with the change of etchants (oxone (KHSO5), sulfuric acid (H2SO4)) concentration. The galvanic corrosion rate of Cu was increased by the increase of the oxone and sulfuric acid concentrations, which lead to the increase of cathodic reactant such as HSO5 − and H+ ions. And the degree of galvanic corrosion rate of Cu (Δisoft etching = icouple, (Cu-Au) - icorr, Cu) decreased with the decrease of the oxone and sulfuric acid concentrations.
Fabrication of Mg–Ni–Sn alloys for fast hydrogen generation in seawater
Oh, SeKwon,Cho, TaeHee,Kim, MinJoong,Lim, JeongHoon,Eom, KwangSup,Kim, DoHyang,Cho, EunAe,Kwon, HyukSang Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.12
<P><B>Abstract</B></P> <P>Mg-2.7Ni-x wt.% Sn(x = 0–2) alloys were fabricated to promote hydrogen generation kinetics of Mg-2.7Ni alloy. The Sn in Mg-2.7Ni-Sn alloys exists as Mg<SUB>2</SUB>Sn phase at the grain boundary and solid solution at the Mg matrix. The Mg<SUB>2</SUB>Sn at the grain boundary acts as the initiation site for pitting corrosion and the dissolved Sn in the alloy causes pitting corrosion by locally breaking the surface oxide film in the Mg matrix in seawater. The Mg-2.7Ni-1Sn alloy showed an excellent hydrogen generation rate of 28.71 ml min<SUP>−1</SUP> g<SUP>−1</SUP>, which is 1700 times faster than that of pure Mg due to the combined action of galvanic and intergranular corrosion as well as pitting corrosion in seawater. As the solution temperature was increased from 30 to 70 °C, the hydrogen generation rate from the hydrolysis of the Mg-2.7Ni-1Sn alloy was dramatically increased from 34 to 257.3 ml min<SUP>−1</SUP> g<SUP>−1</SUP>. The activation energy for the hydrolysis of Mg was calculated to be 43.13 kJ mol<SUP>−1</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Mg–Ni–Sn alloys were specially designed to fast generate H<SUB>2</SUB> in seawater. </LI> <LI> The Mg<SUB>2</SUB>Sn at the grain boundary acts as the initiation site for pitting corrosion. </LI> <LI> The dissolved Sn causes pitting corrosion by locally breaking the surface oxide film. </LI> <LI> H<SUB>2</SUB> generation rate of Mg-2.7Ni-1Sn was 1700 times faster than that of pure Mg in seawater. </LI> <LI> Enhanced performance was attributed to pitting, galvanic and intergranular corrosion. </LI> </UL> </P>
Joomin Kim,Sekwon Oh,Daewon Kim 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10
In this paper, the implementation of a work distribution function for tele-operation under multi-user and multi-robot environments is described. First of all, XML-based UDS(Unit-task Description Structure) is defined to make task scenarios and to distribute the work to multi-users. Considering the role of users and control methods, various kinds of switching modes are defined, and a switching controller is designed. To prove the work distribution function, a simulation environment including a Marilou robotic simulator based slave robot environment is implemented. In this environment, the effectiveness of the work distribution function is tested.