Promotion of electrochemical oxygen evolution reaction by chemical coupling of cobalt to molybdenum carbide

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>

Increased Glycogen Synthase Kinase-3β mRNA Level in the Hippocampus of Patients with Major Depression: A Study Using the Stanley Neuropathology Consortium Integrative Database

DongHoon Oh,YongChon Park,SeokHyeon Kim 대한신경정신의학회 2010 PSYCHIATRY INVESTIGATION Vol.7 No.3

Objective-Glycogen synthase kinase-3β (GSK-3β) has become recognized as a broadly influential enzyme affecting diverse range of biological functions, including gene expression, cellular architecture, and apoptosis. The results of previous studies suggest that GSK-3β activity may be increased in the brain of patients with major depressive disorders (MDD). A recent animal study reported increased GSK-3β messenger ribonucleic acid (mRNA) level in the hippocampus of those with depression. However, few studies have investigated GSK-3β activity in the brain of patients with MDD. Methods-In order to test whether patients with MDD have an increase in GSK-3β activity in the brain compared to normal controls, we explored GSK-3β expression level in all brain regions by using the Stanley Neuropathology Consortium Integrative Database (SNCID), which is a web-based method of integrating the Stanley Medical Research Institute data sets. Results-The level of GSK-3β mRNA expression in the hippocampus was significantly increased in the MDD group (n=8) compared with the control group (n=12, p<0.05). Spearman’s test also reveals that GSK-3β mRNA expression levels were significantly correlated with nitric oxide synthase 1 (NOS1)(ρ=0.70, p<0.0001) and stathmin-like 3 (STMN3)(ρ=0.70, p<0.0001) in the hippocampus. Conclusion-Our results correspond with the results of previous animal studies that reported increased GSK-3β activity in the hippocampus of those with depression. Our findings also suggest that oxidative stress-induced neuronal cell death and abnormal synaptic plasticity in the hippocampus may play important roles in the pathophysiology of major depression.

SMB 공정을 이용한 폐기 TNT와 RDX 혼합 용액의 분리

오동훈(Donghoon Oh),김선희(Sunhee Kim),이근득(Keundeuk Lee),안익성(Iksung Ahn),이창하(Chang-Ha Lee) 한국청정기술학회 2017 청정기술 Vol.23 No.2

자동차용 원적외선 복사열 히터 적용 효과에 관한 연구

오동훈(Donghoon Oh),박태용(Taeyong Park),이성제(Sungje Lee),김재웅(Jaewoong Kim) 한국자동차공학회 2017 한국자동차공학회 학술대회 및 전시회 Vol.2017 No.11

This paper deals with the experimental study for the application effect of far-infrared radiation heater as vehicle cabin heating. Radiation heater can provide quick heating effect direct on the body with low energy consumption. It has no noise, no vibration and no discomfort of heated air when breathing. In this this paper, carbon thread face heating radiation heater that heats about 100℃ is used as a device for the vehicle application. The vehicle wind tunnel test was performed to study the effect on the thermal comfort and heating energy consumption. And also by this test, best radiation heater’s position and proper heating temperature was studied. As a result of vehicle test, thermal comfort level reaching time is reduced by 30~40%, heating energy consumption is reduced by 29~40% at -10, 5℃ ambient temperature.

소성변형특성을 이용한 사실적인 직물 시뮬레이션

오동훈(Donghoon Oh),정문렬(Moonryul Jung),송창근(Changgeun Song),이종완(Jongwan Lee) 한국정보과학회 2006 정보과학회 컴퓨팅의 실제 논문지 Vol.12 No.3

본 논문은 소성변형(plastic deformation)특성을 갖는 직물의 움직임을 시뮬레이션하는 기법을 제안한다. 소성은 탄성과 반대되는 개념으로, 물질이 외부의 힘에 의해 변형되었을 때, 초기상태로 완전히 회복되지못하는 성질이다. 직물은 파티클 모델(particle model)을 이용하여 모델링하며, 파티클간의 상호작용은 바로 인접한 파티클간의 순차연결과 한 파티클 건너에 있는 파티클간의 교차연결을 설정함으로써 표현한다. 순차연결은 직물의 압축과 인장변형을, 교차연결은 직물의 굽힙변형을 표현한다. 연결은 스프링으로 모델링하는데, 순차연결은 탄성스프링으로, 교차연결은 변형정도에 따라, 탄성스프링 또는 소성스프링으로 모델링한다. 본 논문은 기존의 파티클 모델에서 사용하는 탄성스프링에 소성스프링을 추가하여 직물의 소성변형현상을 표현한 것이다. 그 결과, 굽힘주름과 영구변형된 구김주름, 그리고 주름이 직물 전체에 고루 분포되는 현상을 시뮬레이션할 수 있었다. 연결의 탄성스프링과 소성스프링을 모델링할 때 직물운동방정식 수치해법의 안정성을 보장하기 위해 직물 시스템의 강성 메트릭스 (stiffness matrix)가 indefinite이 되지 않도록 주의를 기울였다. This paper presents a cloth simulation technique that implements plastic deformation. Plasticity is the property that material does not restore completely to the original state once deformed, in contrast to elasticity. We model cloth using a particle model, and posit two kinds of connections between particles, i.e. the sequential connections between immediate neighbors, and the interlaced connections between every other neighbors. The sequential connections represent the compression and tension of cloth, and the interlaced connections the bending in cloth. The sequential connections are modeled by elastic springs, and the interlaced connections by elastic or plastic spring depending on the amount of the current deformation of the connections. Our model is obtained by adding plastic springs to the existing elastic particle model of cloth. Using the new model, we have been able to simulate bending wrinkles, permanently deformed wrinkles, and small wrinkles widely distributed over cloth. When constructing elastic and plastic spring models for sequential and interlaced connections, we took pain to prevent the stiffness matrix of the whole cloth system from being indefinite, in order to help achieve physical stability of the cloth motion equation and to improve the effectiveness of the numerical method.

Comparison of the muscle activity in the normal and forward head postures based on the pressure level during cranio-cervical flexion exercises

( Donghoon Kang ),( Taeyoung Oh ) 대한물리치료학회 2019 대한물리치료학회지 Vol.31 No.1

Purpose: This paper proposes proper and effective neck exercises by comparing the deep and superficial cervical flexor muscle activities and thickness according to the pressure level during cranio-cervical flexion exercises between a normal posture group and forward head posture group. Methods: A total of 20 subjects (8 males and 12 females) without neck pain and disabilities were selected. The subjects’ craniovertebral angles were measured; they were divided into a normal posture and a forward head posture group. During cranio-cervical flexion exercises, the thickness of the deep cervical flexor neck muscle and the activity of the surface neck muscles were measured using ultrasound and EMG. Results: The results showed that the thickening of the deep cervical flexor was increased significantly to 28 and 30 mmHg in the forward head posture group. The sternocleidomastoid muscle activity increased significantly to 24, 26, 28, and 30 mmHg in the forward head posture group. The anterior scalene muscle activity increased significantly to 26, 28, and 30mmHg in the forward head posture group. A significant difference of 26, 28, and 30 mmHg in the sternocleidomastoid and anterior scalene muscles was observed between two groups. Conclusion: To prevent a forward head posture and maintain proper cervical curve alignment, the use of the superficial cervical flexor muscles must be minimized. In addition, to perform a cranio-cervical flexion exercises to effectively activate the deep cervical flexor muscles, 28 and 30 mmHg for normal posture adults and 28 mmHg for adults with forward head postures are recommended.

Session 3 Marketing Science I

Donghoon Kim,Seung-yon Lee,Hyunjeong Kim,Do-Won Seol,Sejo Oh,Min Sung,Younchan Kim,Hye Mi Chung 한국마케팅과학회 2006 한국마케팅과학회 학술대회 발표 논문집 Vol.- No.-

Experiences of magnetic resonance imaging scanning in patients with pacemakers or implantable cardioverter-defibrillators

( Donghoon Han ),( Si-hyuck Kang ),( Youngjin Cho ),( Il-young Oh ) 대한내과학회 2019 The Korean Journal of Internal Medicine Vol.34 No.1

Background/Aims: Despite the U.S. Food and Drug Adminstration approving a magnetic resonance imaging (MRI)-conditional pacemaker system in 2011, many physicians remain reluctant to perform MRI scanning in patients with cardiac implantable electronic devices. Herein, we aimed to evaluate the real-world safety of MRI in these patients. Methods: This single-center retrospective study examined the interrogation data and outcomes of patients with pacemakers or implantable cardioverter defibrillators who underwent MRI. MRI interrogation data were collected pre- and post-MRI and after 1 month of follow-up; these included the lead impedance, measured P- and R-wave amplitudes, and capture threshold. We compared these results between the magnetic resonance (MR)-conditional and conventional groups. Results: From September 2013 to December 2015, 35 patients with cardiac implantable electronic devices underwent 43 MRI scans, with a mean follow-up of 5 months. Among these 35 patients, 14 (40%) had MR-conditional devices and 21 (60%) had conventional devices. Seven patients had high voltage devices, which were all the conventional type. There were no adverse events associated with MRI during the follow-up period, and there were no significant differences in the interrogation data changes between the conventional and MR-conditional groups. Conclusions: This single-center retrospective study found that MRI can be performed safely in patients with pacemakers or implantable cardioverter defibrillators, regardless of the MRI support, as long as appropriate precautions are taken.

수소생산용 개질기 가열로의 무화염 연소 적용기술

신동훈(Donghoon Shin),최종균(Chonggun Choi),오남균(Namgyun Oh),이성희(Sunhee Lee),김보근(Bokeun Kim) 한국가스학회 2017 한국가스학회 학술대회논문집 Vol.2017 No.11

OFDMA상향링크 시스템을 위한 시간동기 추정 알고리듬

강동훈(Donghoon Kang),이용욱(Yongwook Lee),오왕록(Wangrok Oh) 한국통신학회 2012 한국통신학회 학술대회논문집 Vol.2012 No.2