Heating and cooling performance analysis using CAE of water-cooled 15kW class permanent magnet motor

Insoo Song,Yunyong Choi,Eunsil Han,Myeonggyun Choi 한국자기학회 2022 한국자기학회 학술연구발표회 논문개요집 Vol.32 No.2

Bi-modified Pt supported on carbon black as electro-oxidation catalyst for 300 W formic acid fuel cell stack

Choi, Mihwa,Ahn, Chi-Yeong,Lee, Hyunjoon,Kim, Jong Kwan,Oh, Seung-Hyeon,Hwang, Wonchan,Yang, Seugran,Kim, Jungsuk,Kim, Ok-Hee,Choi, Insoo,Sung, Yung-Eun,Cho, Yong-Hun,Rhee, Choong Kyun,Shin, Woonsup Elsevier 2019 Applied Catalysis B Vol.253 No.-

<P><B>Abstract</B></P> <P>Formic acid is a chemical with a simple molecular structure containing hydrogen. This liquid at room temperature is easy to handle and has a low toxicity, and is thus in the spotlight as a fuel. In particular, formic acid is an excellent fuel candidate because it can be operated at low temperatures when applied as a fuel in fuel cells with a high theoretical open-circuit voltage (1.48 V). However, it has a drawback in that the electrode catalyst is deactivated due to the generation of CO intermediates when formic acid is oxidized during cell operation. Therefore, to prevent this, an irreversibly adsorbed Bi on Pt catalyst is applied to a direct formic acid fuel cell (DFAFC) anode because it is easy to synthesize and economical. Physical analyses such as transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were conducted, and electrochemical evaluations were performed through half-cell and single-cell level tests. The results revealed that the formic acid oxidation reaction activity of the Bi-modified Pt/C was 13 times higher than that of the conventional catalyst at 0.58 V. Further, a DFAFC stack was fabricated using the Bi-modified Pt/C, which yielded a power of 300 W. These results suggest that a simple synthesis method can be applied to fabricating industrially available DFAFC stacks.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bi-modified Pt catalyst is applied to a direct formic acid fuel cell (DFAFC) anode. </LI> <LI> Bi was irreversibly adsorbed on Pt catalyst by a simple synthetic strategy. </LI> <LI> Bi-modified Pt/C showed significantly high formic acid oxidation reaction activity. </LI> <LI> A DFAFC stack fabricated using Bi-modified Pt/C yielded a power of 300 W. </LI> <LI> The simple synthetic strategy can be applied to achieving DFAFC stacks commercially. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Highly dispersed and CO_ad-tolerant Pt_shell-Pd_core catalyst for ethanol oxidation reaction: Catalytic activity and long-term durability

Choi, Insoo,Lim, Dong-Hee,Shin, Dong Yun Elsevier 2018 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.43 No.24

<P><B>Abstract</B></P> <P>Highly dispersed Pt<SUB>shell</SUB>-Pd<SUB>core</SUB> catalyst is synthesized via an electroless deposition and a galvanic displacement. From electrochemical analysis, the catalyst is confirmed to be active toward an ethanol oxidation reaction for a prolonged time, and is more resistive against CO<SUB>ad</SUB>-poisoning than a conventional Pt/C catalyst. The stable activity of Pt<SUB>shell</SUB>-Pd<SUB>core</SUB>/C is ascribed to the modified electronic property of Pt over-layer, which leads to a weak CO-adsorption strength with a high affinity for OH. The weakened binding property of surface Pt with CO<SUB>ad</SUB> was experimentally confirmed by conducting a CO<SUB>ad</SUB>-stripping and by measuring an electrochemically active surface area of the catalyst over multiple cycles. The CO<SUB>ad</SUB> oxidation ability of as-synthesized catalyst is further proved by a computational method via density functional theory (DFT) calculation. The result presents a potential application of the catalyst for the efficient ethanol oxidation in a direct ethanol fuel cell.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pt<SUB>shell</SUB>-Pd<SUB>core</SUB>/C catalyst was synthesized by electroless deposition and displacement. </LI> <LI> The catalyst is more active in ethanol oxidation reaction than commercial Pt catalyst. </LI> <LI> The catalyst showed moderate CO<SUB>ad</SUB>-tolerance and long-term durability. </LI> <LI> The stable activity was ascribed to the modified electronic property of the catalyst. </LI> <LI> The higher CO oxidation capacity was supported by density functional theory. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>A Pt<SUB>shell</SUB>-Pd<SUB>core</SUB>/C catalyst was electrochemically synthesized, and exhibited higher catalytic activity with CO<SUB>ad</SUB>-tolerance toward ethanol oxidation at prolonged time. The core-shell configuration induced the change in the binding ability of catalyst with adsorbate, which ultimately increased its CO oxidation capacity.</P> <P>[DISPLAY OMISSION]</P>

Dysfunctional Beliefs about Sleep in Cancer Patients Can Mediate the Effect of Fear of Progression on Insomnia

Insoo Kim,Kikyoung Yi,이주희,Kyumin Kim,Soyoung Youn,서수연,Jiyeon Kim,Jung mun choi,정석훈 대한수면학회 2019 sleep medicine research Vol.10 No.2

Sleep Med Res > Volume 10(2); 2019 > Article Original Article Sleep Medicine Research (SMR) 2019; 10(2): 83-89. Published online: Dec 31, 2019 DOI: https://doi.org/10.17241/smr.2019.00451 Dysfunctional Beliefs about Sleep in Cancer Patients Can Mediate the Effect of Fear of Progression on Insomnia Insoo Kim, MD1, Kikyoung Yi, MD2, Joohee Lee, MD1, Kyumin Kim, MD1, Soyoung Youn, MD1, Sooyeon Suh, PhD3, Jiyeon Kim, PhD4, Jung Mun Choi, BA1, Seockhoon Chung, MD, PhD1 1Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 2Department of Psychiatry, Yongin Mental Health, Yongin, Korea 3Department of Psychology, Sungshin Women’s University, Seoul, Korea 4Department of Art Therapy, Hanyang Cyber University, Seoul, Korea Correspondence: Seockhoon Chung, MD, PhD, Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, 86 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea, Tel +82-2-3010-3411, Fax +82-2-485-8381, E-mail schung@amc.seoul.kr Received Oct 21, 2019 Revised Nov 1, 2019 Accepted Nov 5, 2019 Copyright© 2019 The Korean Society of Sleep Medicine Abstract Background and Objective The role of the dysfunctional belief about sleep is important for the development of insomnia among cancer patients. This study intended to investigate whether dysfunctional belief about sleep mediates the relationship between fear of progression and insomnia in cancer patients. Methods Three hundred and thirty-seven cancer patients participated in our study. Dysfunctional belief about sleep, severity of insomnia, depression, fear of progression, and anxiety were measured using the following questionnaires: Cancer-related Dysfunctional Beliefs about Sleep (C-DBS); Insomnia Severity Index (ISI); Patient Health Questionnaire-9 (PHQ-9); Fear of Progression (FoP); and the state subcategory of State and Trait Anxiety Inventory (STAI). Path analysis was used to clarify the relationships among the variables. Since C-DBS consists of two items, i.e., Q1-immune & Q2-recurrence, we implemented an additional path analysis including these variables separately. Results C-DBS mediated the effect of FoP (β = 0.36, p < 0.001) and patient sex (β = 0.13, p = 0.009) on ISI. PHQ-9 (β = 0.32, p < 0.001) and STAI (β = -0.09, p = 0.071) had a direct influence on ISI scores. In our second path analysis, Q1-immune item mediated the effect of FoP (β = 0.19, p < 0.001) on ISI, and Q2-recurrence item mediated the effect of FoP (β = 0.23, p < 0.001) and patient sex (β = 0.09, p = 0.019) on ISI. Conclusions Our path analysis model indicated that C-DBS mediates the effect of FoP and patient sex on ISI. Our second path analysis results suggested that there could be an internal process of Q1 and Q2 item. Efforts to reduce dysfunctional beliefs should be considered as well as management of fear of progression for better sleep of cancer patients.

Current Researches and Prospects of Soybean Cyst Nematode

Insoo Choi,Namsook Park,Eulsoo Yun,Donggeun Kim 한국응용곤충학회 2017 한국응용곤충학회 학술대회논문집 Vol.2017 No.10

Plant-parasitic nematodes causes yield losses of more than $100 million per year in the world. Among them, soybeancyst nematode (Heterodera glycines Ichinohe) causes the greatest yield loss to soybean compared to any other pest worldwide.SCN causes yield reductions by feeding on plant nutrients, retarding root growth and inhibiting Bradyrhizobium japonicum(Kirchner) Buchanan nodulation. The primary methods for controlling SCN include planting resistant cultivars and rotationwith nonhost crop. In order to control SCN, we should be breeding resistant soybean cultivars which has resistant genefor this pest. The research that can minimize the damage of the soybean yield is still insufficient, comprehensive andsystematic research is urgently required. Current researches in our lab are discussed.

Mechanically Powered Transparent Flexible Charge-Generating Nanodevices with Piezoelectric ZnO Nanorods

Choi, Min-Yeol,Choi, Dukhyun,Jin, Mi-Jin,Kim, Insoo,Kim, Sang-Hyeob,Choi, Jae-Young,Lee, Sang Yoon,Kim, Jong Min,Kim, Sang-Woo WILEY-VCH Verlag 2009 ADVANCED MATERIALS Vol.21 No.21

<B>Graphic Abstract</B> <P>Transparent flexible charge-generating piezoelectric nanodevices are developed. The resulting integrated nanodevice generates a noticeable current when it is pushed by application of an external load. Piezoelectric ZnO nanorod-based nanodevices with embossed PdAu top electrodes produce the highest output current density of approximately 10 μA cm<SUP>−2</SUP> at a load of 0.9 kgf. <img src='wiley_img/09359648-2009-21-21-ADMA200803605-content.gif' alt='wiley_img/09359648-2009-21-21-ADMA200803605-content'> </P>

Fabrication of copper nanoparticles in a thick polyimide film cured by rapid thermal annealing.

Choi, Min Young,Choi, Dong Joo,Ahn, Key-One,Ro, Insoo,Kim, Young-Ho,Suh, Sang-Hee American Scientific Publishers 2012 Journal of Nanoscience and Nanotechnology Vol.12 No.4

<P>We investigated the imidization of a polyimide (PI) and the formation of Cu nanoparticles in a PI film by curinga precursor of PI (polyamic acid (PAA) dissolved in n-methyl-2-pyrrolidinone) in a reducing atmosphere in the rapid thermal annealing (RTA) system. A Cu film was deposited onto the SiO2/Si substrate, and the PAA was spin-coated onto the Cu film. After the PAA reacted with the Cu film, soft-baking was performed to evaporate the solvent. Finally, the PAA was imidized to PI at 450 degrees C by curing in a reducing atmosphere with the RTA. Fourier transform infrared spectroscopy showed that the PAA was successfully imidized by the RTA. X-ray diffraction patterns revealed that Cu nanoparticles formed by RTA curing at 450 degrees C for 5 minutes in a reducing atmosphere, and transmission electron microscopy showed that Cu nanoparticles about 6.5 nm in size were uniformly dispersed in the PI film. Curing by RTA is an attractive method because it takes only a few minutes.</P>

Morphological, Cytological and Molecular Evidence for Intersubgeneric F₁ Hybrid between Glycine max × G. tomentella

Insoo Choi(최인수),Yong-Chul Kim(김용철) 한국생명과학회 2008 생명과학회지 Vol.18 No.4

본 연구는 콩의 Glycine tomentella와 G. max 뱀콩의 종간교잡으로부터 얻은 F₁식물체의 검증을 위하여 형태적, 세포 유전학적, 그리고 분자유전학적 연구를 하였던 바 그 결과를 요약하면 다음과 같다. F₁ 식물체의 암술과 수술, 꽃 색깔, 그리고 생육습관 등의 형태적 특징들은 G. tomentella 의 특징들을 따르거나 중간적 특성을 나타내었다. G. tomentella (2n=38) 와 G. max 뱀콩(2n=40)의 F₁식물체의 염색체수는 2n=39를 가지고 있었다. Esterase와 peroxidase의 동위효소 반응의 결과에서도 F₁ 식물체는 G. tomentella과 G. max 뱀콩의 중간적인 밴드유형을 나타내었다. RAPD 분석결과 62 primers들로부터 얻은 F₁ 식물체 밴드양상이 모두 G. tomentella와 G. max 뱀콩 양친으로부터 물려받은 것들로 판명되었다. 형태적, 세포학적 그리고 분자유전학적 결과들을 종합하여 볼 때, 본 연구의 G. max와 G. tomentella의 종간교잡으로부터 얻은 F₁ 식물체는 진정 F₁ 교배체로 판명되었다. F₁ 식물체의 임성회복을 위한 연구와 RAPD 분석에서 나타난 모계유전양상(OPA02, OPA09)과 부계유전양상(OPD05)을 보인 결과에 대한 지속적인 연구를 위한 노력이 요구된다. This study was carried out to demonstrate morphological, cytological and molecular evidence for intersubgeneric F₁ hybrid between Glycine tomentella and G. max cv. 'Baemkong'. Morphological features of F₁ plant for pistil and stamen, flower color and growth habit showed intermediate type between G. tomentella and G. max cv. 'Baemkong'. Chromosome number of F₁ plant was 2n=39, which explained the evidence of F₁ hybrid between G. tomentella (2n=38) and G. max cv. 'Baemkong' (2n=40). Polyacrylamide isoelectric focusing pattern for esterase and peroxidase also showed that the F₁ plant was true F₁ hybrid between G. tomentella and G. max cv. 'Baemkong'. From RAPD analysis, we identified that 62 primers showing bands in F₁ hybrid had both bands from G. tomentella and G. max cv. 'Baemkong', which suggested that this was true F₁ hybrid. Based on our results from morphological, cytological and molecular analyses, we suggest that the F₁ plant was true intersubgeneric hybrid between G. tomentella and G. max cv. 'Baemkong'. Our results still remain us further study to recover fertility of F₁ hybrids. The occurrence of maternal and/or paternal inheritance in F₁ hybrid from intersubgeneric cross between G. tomentella and G. max cv. 'Baemkong' need to be explained.

Electrochemical Conversion of Carbon Dioxide to Formic Acid on Sn—Zn Alloy Catalysts Prepared by Electrodeposition

Choi, Insoo,Kim, Hak-Yoon,Ahn, Sang Hyun,Hwang, Seung Jun,Yoo, Sung Jong,Kim, Ho Young,Choi, Jihui,Park, Hyan Joo,Jang, Jong Hyun,Kim, Soo-Kil American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.10

<P>Electrochemical conversion of carbon dioxide to formic acid was attempted on Sn-Zn alloy catalysts. The alloy catalysts were fabricated by electrodeposition, and their compositions were controlled by varying the concentration of the precursor solution. A home made proton exchange membrane-based electrochemical cell was used for the reduction of carbon dioxide. The concentration of formic acid produced and the conversion efficiency were determined via electrolysis and high performance liquid chromatography analysis. The effect of the alloy composition on the amount of formic acid generated and the conversion efficiency was evaluated, and alloy composition was found to have a strong influence on these variables. It was thus concluded that the conversion of carbon dioxide to formic acid can be enhanced by alloying Zn with Sn.</P>

Analysis of electromagnetic field characteristics considering thermal characteristics to establish an optimized design model for 15kW-class motors

Insoo Song,Eunsil Han,Myeonggyun Choi,Yunyong Choi 한국자기학회 2022 한국자기학회 학술연구발표회 논문개요집 Vol.31 No.2