PdBi bimetallic catalysts including polyvinylpyrrolidone surfactant inducing excellent formic acid oxidation reaction and direct formic acid fuel cell performance

Yang, Seungwon,Yang, Jongwon,Chung, Yongjin,Kwon, Yongchai Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.27

<P><B>Abstract</B></P> <P>PdBi bimetallic catalysts are synthesized while their catalytic activity and stability for formic acid oxidation reaction (FAOR) and direct formic acid fuel cell (DFAFC) performance are evaluated. According to investigations, Pd<SUB>2</SUB>Bi<SUB>1</SUB>/C catalyst including low Pd amount promotes oxygen desorption with enhancement in CO poisoning resistance. With that, indirect formic acid oxidation reaction (IFAOR) and its stability are improved. To further improve the FAOR, polyvinylpyrrolidone (PVP) surfactant is contained due to its amphiphilic property reducing Bi aggregation. To determine optimal amount of the PVP, analysis using TEM and XPS is performed and the results are verified by density functional theory (DFT). According to TEM, in 0.22 PVP-Pd<SUB>2</SUB>Bi<SUB>1</SUB>/C catalyst, PdBi has small size (∼5 nm) and is well-dispersed with widest E<SUB>d</SUB>- E<SUB>F</SUB> of 3.85 eV, proving the catalyst induces effective CO-poisoning resistance and less Bi aggregation. These results are also compatible with trend in FAOR measured by cyclic voltammogram (CV). Even long-term stability, the catalyst maintains catalytic activity well. The best performance of DFAFC using the catalyst (32.7 mW cm<SUP>−2</SUP>·Pd<SUB>g</SUB> <SUP>−1</SUP>) indicates that 0.22 PVP- Pd<SUB>2</SUB>Bi<SUB>1</SUB>/C is excellent catalyst for FAOR and DFAFC performances.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PbBi bimetallic structures are suggested as anodic catalyst of DFAFC. </LI> <LI> Pd<SUB>2</SUB>Bi<SUB>1</SUB>/C promotes oxygen desorption with enhancement in CO poisoning resistance. </LI> <LI> Pd<SUB>2</SUB>Bi<SUB>1</SUB>/C facilitates IFAOR and long-term stability. </LI> <LI> PVP surfactant play a critical role in reducing Bi aggregation. </LI> <LI> DFAFC using 0.22 PVP-Pd2Bi1/C catalyst shows excellent performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

과산화수소를 이용한 Pt계 촉매의 인산 이온 피독 특성 정량 평가 방법

Seungwon Yang,Jeongjin Park,정용진,권용재 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.3

A new measurement method is suggested to quantify the phosphate poisoning of cathodic Pt catalyst for HT-PEMFC. To do that, hydrogen peroxide was used as an indicator to reduce the error which has been occurred in conventional electrochemical measurement such as CV or ORR RDE with high concentration of phosphate ions. As a result, the current density induced from the reaction of hydrogen peroxide decomposition increased proportionally to the concentration of phosphate ion while the conventional methods show has a significant error with high concentration of phosphate ion. Thus, it is confirmed that the suggested way is superior to the conventional measurement method for the quantification of phosphate ion poisoning in an atmosphere similar to the actual operation condition of HT-PEMFC. 본 연구에서는 HT-PEMFC 공기극용 Pt계열 연료극 촉매의 인산이온 피독 특성에 대한 새로운 평가 방법을 제시하였다. 이를 위하여, 기존의 전기화학적 인산이온 피독 측정법인 CV와 ORR RDE 측정법이 갖고 있는 문제점을 저감하기 위하여, 과산화수소를 Pt 촉매와의 반응물로 이용하여 고농도 인산 이온 분위기에서의 내피독성 측정값 오차를감소시켰다. 그 결과 인산이온 농도 0.1M 이하의 저농도와 0.5M 이상의 고농도에서 인산농도 대비 전류밀도의 변화가 직선적으로 나타나, 실제 HT-PEMFC의 구동 환경과 유사한 고농도의 인산이온 분위기에서의 Pt계 인산이온 피독정량화에 대하여 기존의 측정방법에 비해 우수함을 확인하였다.

Enhancements in catalytic activity and duration of PdFe bimetallic catalysts and their use in direct formic acid fuel cells

Seungwon Yang,Yongjin Chung,이국승,Yongchai Kwon 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.90 No.-

The palladium–iron based bimetallic catalysts (PdxFey/Cs) and facile synthetic method are introduced toenhance the catalytic activity and operational duration for direct formic acid fuel cells. To improve theproperties of PdxFey/C catalysts, such as degree of PdFe alloy and its crystallinity, heat treatment isconducted at 600 C. According to results, the Pd–Fe bond and Fe metal particle are formed after the heattreatment, while iron oxides and Pd particles are observed in the untreated samples. Electrochemicalevaluations for measuring the formic acid oxidation reaction rate demonstrates heat treated Pd3Fe1/C(HT-Pd3Fe1/C) is the best catalysts of six samples which are synthesized by using different Pd to Fe ratios(3:1, 1:1, 1:3) before and after heat treatment. This is because the HT-Pd3Fe1/C has high Pd–Fe alloyingand Pd contents. Through the heat treatment, the indirect formic acid oxidation reaction way is activatedand the resistance to CO poisoning is significantly improved. The maximum power density of directformic acid fuel cells using HT-Pd3Fe1/C whose open circuit voltage is 0.83 V is 137 mW cm 2, which is 1.6and 1.9 times higher than that of direct formic acid fuel cells using untreated catalyst and Pd/C.

개방형 BIM 기반 설계품질 자동검증 프로그램 개발

양승원(Seungwon Yang),손영석(Youngseok Sohn),강성종(Seongjong Kang),유석준(Seokjoon You) (사)한국CDE학회 2015 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2015 No.동계

광학계를 결합한 PSD 센서의 렌즈 왜곡 보정

양승원(Seungwon Yang),김동민(Dongmin Kim),김승균(Seung Keun Kim),석진영(Jin Young Suk) 한국항공우주학회 2018 한국항공우주학회 학술발표회 논문집 Vol.2018 No.11

Balance trainer training with transcutaneous electrical nerve stimulation improves spasticity and balance in persons with chronic stroke

Yang, Youjin,Lee, Jungeun,Choi, Wonjae,Joo, Younglan,Lee, Seungwon korean Academy of Physical Therapy Rehabilitation 2020 Physical therapy rehabilitation science Vol.9 No.2

Objective: The purpose of this study was determine the effect of Balance Trainer training with Transcutaneous Electrical Nerve Stimulation (TENS) on spasticity and balance in persons with chronic stroke. Design: Randomized controlled trial. Methods: A total of 30 subjects with hemiparetic stroke were recruited and randomly divided into the Balance Trainer training with TENS group (n=15) and Balance Trainer training with placebo TENS group (n=15). The Balance Trainer training with TENS group practiced additional Balance Trainer training with TENS for 30 minutes a day, 5 days per a week during 4 weeks and the Balance Trainer training with placebo TENS group practiced additional Balance Trainer training with placebo TENS for the same period. Spasticity and balance were assessed by ability (static balance, dynamic balance) and were measured before and after the 4-week programs. Results: The result of spasticity and dynamic balance were improved significantly in both groups (p<0.05). The Balance Trainer training with TENS group showed significantly greater improvement in spasticity of the gastrocnemius & dynamic balance, compared to the Balance Trainer training with placebo TENS group (p<0.05). The Balance trainer training with TENS group showed a significant improvement in static balance, especially during the eye-closed condition (p<0.05). Conclusions: The Balance Trainer training with TENS was effective in improving spasticity and balance in subjects with chronic stroke. Based on these results, it is suggested that Balance Trainer training with TENS could clinically be used more actively in conjunction with conventional physical therapy.

A Novel User Selection Method That Maximizes the Determinant of Channel Auto-Correlation for Multi-User MIMO Systems with Zero-Forcing Precoder

YANG, Hyunwook,HAN, Yeongyu,CHOI, Seungwon 'Institute of Electronics, Information and Communi 2014 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.eb97 No.7

<P>In a multi-user multiple-input multiple-output (MU-MIMO) system that adopts zero-forcing (ZF) as a precoder, the best selection is the combination of users who provide the smallest trace of the inverse of the channel auto-correlation matrix. Noting that the trace of the matrix is closely related to the determinant, we search for users that yield the largest determinant of their channel auto-correlation matrix. The proposed technique utilizes the determinant row-exchange criterion (DREC) for computing the determinant-changing ratio, which is generated whenever a user is replaced by one of a group of pre-selected users. Based on the ratio computed by the DREC, the combination of users providing the largest changing ratio is selected. In order to identify the optimal combination, the DREC procedure is repeated until user replacement provides no increase in the determinant. Through computer simulations of four transmit antennas, we show that the bit error rate (BER) per signal-to-noise ratio (SNR) as well as the sum-rate performance provided by the proposed method is comparable to that of the full search method. Furthermore, using the proposed method, a partial replacement of users can be performed easily with a new user who provides the largest determinant.</P>

A Detection Algorithm to Reduce the Condition Number of the Channel Matrix

YANG, Hyunwook,LEE, Gyuyoung,CHOI, Seungwon 'Institute of Electronics, Information and Communi 2015 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.eb98 No.2

동삼동패총 출토 그물무늬토기 고찰

양성혁,박승원 국립중앙박물관 2014 고고학지 Vol.20 No.-

동삼동패총에서 출토된 그물무늬토기는 신석기시대의 그물이 토기 겉면에 찍혀 있는 유일한 것으로 당시 그물의 실체와 방적 기술을 연구할 수 있는 귀중한 자료로 평가받고 있다. 그럼에도 불구하고 그동안 본 자료에 대한 기초적인 정보가 충분히 제공되지 않아 신석기시대 그물에 대한 제대로 된 연구가 이루어지지 않았다. 이에 본 자료의 출토 현황 및 3D 현미경 관찰 결과 등 기초 정보를 제공할 목적으로 이 글을 작성하였다. 우선 그동안 일부에서 동삼동패총 하층에서 출토된 것으로 보고 신석기시대 전기의 유물로 평가되었던 본 자료가 실제로는 이중구연토기를 대표로 하는 문화층에서 출토된 유물임을 밝혔다. 이와 함께 능형집선문 혹은 조우문과 유사한 사격자문, 동체 상부에만 시문된 무늬, 장석이 혼입된 태토 등을 근거로 본 자료가 봉계리식토기 단계일 가능성을 조심스럽게 제시하였다. 본 자료에 찍힌 그물감을 3D 현미경으로 관찰한 결과, 그물감은 단사 2올 이상을 꼬아서 만든 합사임이 확인되었다. 이 실 꼬임의 각도는 평균 38°로, 현재 기술로 이 정도의 꼬임 각도를 유지하기 위해서는 3합사가 적절하지만 당시 가락바퀴로 단사 3올을 동시에 꼬기에는 어렵다는 점에서 단사 2올을 강하게 꼬아서 만든 2합사일 가능성을 제시하였다. 그물감의 원료는 강도가 크고 내수성이 좋은 대마로 추정하였다. 동삼동패총을 비롯해 동남해안 신석기시대 유적에서는 그물추가 거의 출토되지 않고 있다는 점에서 이 지역에서는 그물추가 없는 형태로 사용했던 것으로 추정하였다. 이와 함께 그물과 그물추의 존재가 곧 그물어법의 존재라는 단순한 구도에서 벗어나 선사시대의 그물 사용례를 들어 그물이 단순히 고기잡이 도구일 뿐만 아니라 사냥과 운송 등 다양한 용도로 광범위하게 사용되었다는 점을 재차 강조하였다. The net pattern pottery from Dongsam-dong shell midden represents the only example of pottery decorated with the imprint of a Neolithic net. This paper aims to compile basic information on net pattern pottery, by identifying the context of its discovery and by presenting the results of 3D microscope analysis. Firstly, it was possible to confirm that this type of pottery, which had been seen to have come from the lowest layer of Dongsam-dong shell midden and was therefore regarded as belonging to the Early Neolithic culture, in fact came from the cultural layer represented by double-rimmed pottery(二重口緣土器). In addition, given the presence of rhombus-shaped motifs(斜格子文), the way in which patterns were used to decorate only the upper part of the vessel body, and the use of base clay with feldspar inclusions, it is tentatively suggested that net pattern pottery may in fact belong to the cultural phase represented by Bonggye-ri style pottery. By observing the net imprints on the pottery surface using a 3D microscope, it was possible to identify that the net was made using cord which consisted of more than two same types of single yarn. These yarns had been twisted together at an angle of 38°; in modern spinning technology, three is believed to be the appropriate number of yarns needed to maintain this angle but given that it would have been difficult to twist together three yarns using the spindle whorl available at the time, it is likely that the cord was made by tightly twisting only two yarns. It is inferred that the material used to make the yarns would have been hemp yarns, which was strong and water resistant. The Neolithic sites of the southeast coastal region, including Dongsam-dong Shell Midden, have rarely yielded net sinkers. Based on this fact, therefore, it has been suggested that fishing nets in this region were used without sinkers. In addition, nets would not have been limited to this function alone; nets would have also been used in various ways, such as for hunting or the transportation of goods.

Production interleukin 2 receptor gamma knock-out Micropig® using CRISPR-Cpf1 and nuclear transfer methods

Seungwon Yoon,ChunGyu Park,SangWoo Kim,YoungJune Kim,HyeYeong Yang,HyunYong Choi,SeulGi Lee,HongSung Kim,JunWoo Kim,HyeongSeok Choi,SangJin Hwang,ChangGeun Suk,KyeongSoo Kang,Chang-Gi Hur 한국실험동물학회 2018 한국실험동물학회 학술발표대회 논문집 Vol.2018 No.7