Characteristics of Hot-Dip Znmgal Coatings with Ultra-High Corrosion Resistance

( Sungjoo Kim ),( Seulgi So ),( Jongwon Park ),( Taechul Kim ),( Sangtae Han ),( Suwon Park ),( Heung-yun Kim ),( Myungsoo Kim ),( Doojin Paik ) 한국부식방식학회 2024 Corrosion Science and Technology Vol.23 No.4

Zn-Mg-Al alloy hot-dip galvanized steel sheet has high corrosion resistance. Compared to conventional Zn coating with the same coating thickness, the high corrosion resistance Zn-Mg-Al coating is more corrosionresistant. Various coating compositions are commercially produced and applied in diverse fields. However, these steel sheets typically contain up to 3 wt% magnesium. In recent years, there has been a growing demand for higher corrosion resistance in harsh corrosive environments. Therefore, variations in Mg and Al contents were investigated while evaluating primary properties and performance. As a result, we developed new alloycoated steel with ultra-high corrosion resistance. A Zn-5 wt%Mg-Al coated steel sheet was evaluated for its corrosion resistance and various properties. As the amount of Mg added increased, the corrosion loss tended to decrease. The corrosion resistance of the coated steel sheet in a particular composition, the Zn-5 wt%Mg- Al coating sheet, was about 1.5 to 2 times higher than that of the conventional Zn-3 wt%Mg-Al coating sheet. Ultimately, this ultra-high corrosion-resistance coated steel sheet will provide a robust solution to conserve Zn resources and contribute to a low-carbon society.

Rxfp2, an Insl3 receptor might be associated with the failure of spermatogenesis in Phf7 ko mice

Jieun Kim,Eun-Kyoung Kim,Hae-Rim Kim,Sang-Mi Cho,Danbi Ka,Hoyoung Ghang,Seulgi Park,Mini Lee,Faiz Ur Rahman,Ki-Hoon Lee,Won-Kee Yoon,Young-Suk Won,Hyoung-Chin Kim,Kyoung-Chul Choi,Ki-Hoan Nam 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7

PHD finger protein 7 (Phf7) is a member of the PHF family, which contain the PHD domain known as a histone methylation reader and RING domain known as a E3 ubiquitin ligase. Phf7 is expressed testis, specifically in germ cells and Leydig cells but not in Sertoli cells. The deficiency of Phf7 induces male infertility. And it was found that Phf7 acts as a histone H2A E3 ligase in histone-to-protamine exchange during spermatogenesis. Until now, most studies on Phf7 have been focused on spermatogenesis. Here, we tried to found any phenotypes other than male infertility in the Phf7 Ko mice. We found that there are growth-retardation and reduction of bone mineral density in Phf7 knockout (ko) mice. We also tried to found any mechanism that may associated with abnormal spermatogenesis in the Phf7 ko mice. It is known that Rxfp2 is expressed in the postmeiotic germ cells in testis and that Rxfp2 with Insl3, a hormone released from Leydig cells constitute a paracrine hormone-receptor system in testis. Therefore, we determined the expression level of Insl3 and Rxfp2 in testis of Phf7 ko mice. We found that the Insl3 mRNA level was higher in the ko mice, but the Rxfp2 mRNA expression level was reduced in the mutant mice then wild mice. In conclusion, we suggest that the failure of spermatogenesis observed in Phf7 ko mice might related with the reduced expression of Rxfp2 in the developing germ cells.

분광 분석법을 활용한 국내산 포도 품종 통합 당도 검량식 개발 연구

김상연 ( Sang-yeon Kim ),홍석주 ( Suk-ju Hong ),이창협 ( Chang-hyup Lee ),김응찬 ( Eungchan Kim ),김슬기 ( Seulgi Kim ),김기석 ( Ghiseok Kim ) 한국농업기계학회 2019 한국농업기계학회 학술발표논문집 Vol.24 No.2

한국의 신선농산물 수출액은 최근 3년간 꾸준히 증가하고 있으며 2018년에는 12억 8천만 달러로 전년대비 1억 8200만 달러가 늘어나 역대 최고의 증가액 실적을 기록하였다. 이러한 호재의 배경에는 한류와 함께 퍼져나간 한국산 과일의 인기가 한몫했다고 알려져 있는데, 그중 두드러지는 약진을 보여준 것이 바로 ‘포도’이다. 한국산 포도는 ‘샤인 머스캣’이라 불리는 신품종을 앞세워 특히 중국과 베트남 등의 동남아 지역에서 최근 폭발적인 인기를 얻고 있으며, 특유의 향기와 높은 당도로 최근 국내에서도 그 인기가 날로 상승하고 있다. 그 결과, 오랜 시간 동안 국내 포도 재배의 약 80% 이상을 차지하던 주력 품종인 캠벨과 거봉을 빠른 속도로 대체해 가고 있으며, 이에 따라 국내 포도 재배 트랜드도 급격하게 변화하고 있다. 하지만, 실제 농가를 방문해본 결과 샤인 머스캣을 지원하는 당도 선별기의 보급은 상당히 더딘 편이었으며, 몇 농가에서만 간이 측정기로 당도를 측정해 출하하고 있는 것이 실정이었다. 또한, 주력 품종이 변화하고 있는 과도기인 만큼 아직 샤인 머스캣뿐만 아니라 기존의 캠벨이나 거봉을 함께 재배하는 농가들도 다수 존재하였는데, 이런 경우 정확한 당도 정보를 얻기 위해서는 품종별로 상이한 당도 측정기를 사용해야 한다는 불편함도 있었다. 따라서, 본 연구에서는 캠벨과 거봉 그리고 샤인 머스캣에 대해 한 번에 적용할 수 있는 품종 통합 당도 측정 모델을 개발하고자 하였다. 모델에 사용한 알고리즘으로는 오늘날 농산물산지유통센터 선별기에 주로 보급된 PLSR(Partial Least Squares Regression)과 여기에 추가로 파장 선택법을 적용해 효율을 증가시킨 VIP(Variable Importance in Projection)-PLSR, Beta-Bootstrap-PLSR 등의 통계적인 방식이 있다. 또한, 최근 분광분석 연구들에서 종종 기존의 통계적인 기법보다 개선된 결과를 보여주고 있는 SVR(Support Vector Regression), ANN(Artificial Neural Network), 1D-CNN(1 Dimensional Convolution Neural Network) 등과 같은 머신러닝 기반의 알고리즘들도 접목하여 최적의 통합 당도 검량식 모델을 선정하는 것을 목표로 하였다.

종합미곡처리장에서의 벼 품종 구분을 위한 가시광-근적외선 분광 분석법의 적용 가능성에 관한 연구

김상연 ( Sang-yeon Kim ),홍석주 ( Suk-ju Hong ),김응찬 ( Eungchan Kim ),이창협 ( Chang-hyup Lee ),김슬기 ( Seulgi Kim ),김기석 ( Ghiseok Kim ) 한국농업기계학회 2020 한국농업기계학회 학술발표논문집 Vol.25 No.1

소비자들의 식습관이 다양해지고 고영양, 고기능성 식품에 대한 수요가 증가함에 따라 개량 쌀 품종들이 나날이 고급화되고 있다. 하지만, 아직 국내 대부분의 종합미곡처리장(RPC)에서는 고품질 종자와 저렴한 혼합미의 구분을 전문가의 육안에만 의존하고 있는 실정이다. 물론, 유전자 분석과 같이 정확한 판별 방법도 있으나 이는 시간상으로 보나 경제적으로 볼 때 현장에 적용하기에는 다소 어려움이 있다. 이에 따라, 실제 산업 현장에서 사용할 수 있을 만큼 빠르며 육안검사보다 과학적인 판별 방법이 필요한 상황이다. 최근엔 이러한 문제들에 대한 해결책으로 분광 분석법을 이용한 쌀 품종 구분 연구가 국내외에서 진행되었으나 대부분 소량의 품종을 대상으로 하여 실제 적용 가능성을 확인해보기에는 한계가 있었다. 따라서, 본 연구에서는 현재 국내에서 유통되고 있는 대표적인 쌀 품종 15종을 선정하여 분광 분석법을 활용한 품종 구분의 가능성을 확인하고자 하였다. 분석 알고리즘으로는 기존 분광 분석 분야에서 널리 사용되는 PLS-DA부터 파장선택법을 적용한 VIP-PLS, 인공신경망을 활용한 PCA-ANN, VIP-ANN, PLS-ANN, 그리고 1D-CNN을 사용하였다. 또한, 단일 모델을 사용한 Multi-class classifier뿐만 아니라 One-vs-Rest 방식을 사용하는 Binary classifier 모델들도 비교하여 최적의 품종 구분 모델을 선정하고자 하였다.

Ultrasonic and mechanical soil washing processes for the remediation of heavy-metal-contaminated soil

Kim, Seulgi,Lee, Wontae,Son, Younggyu IOP Publishing 2016 Japanese journal of applied physics Vol.55 No.7

<P>Ultrasonic/mechanical soil washing process was investigated and compared with ultrasonic process and mechanical process using a relatively large lab-scale sonoreactor. It was found that higher removal efficiencies were observed in the combined processes for 0.1 and 0.3 M HCl washing liquids. It was due to the combination effects of macroscale removal for the overall range of slurry by mechanical mixing and microscale removal for the limited zone of slurry by cavitational actions. (C) 2016 The Japan Society of Applied Physics</P>

Sejong Open cluster Survey (SOS). VII. A Photometric Study of the Young Open Cluster IC 1590

Seulgi Kim,Hwangyung Sung,Michael S. Bessell,Beomdu Lim 한국천문학회 2020 天文學會報 Vol.45 No.1

The effect of lower extremity postures on trunk kinematics while sitting

Seulgi Kim,Ilseok Lee,Sangeun Jin 대한인간공학회 2018 대한인간공학회 학술대회논문집 Vol.2018 No.5

Objective: This study aimed to investigate the effect of lower extremity posture on lumbar, thoracic, cervical and head postures while sitting. Background: Previous studies have largely contributed to an understanding of the sitting biomechanics, but those studies have considered the low back as an isolated system and mislead the functional interaction between lower extremity and trunk. Method: Seventeen healthy participants were recruited from the university population, and were asked to sit on a chair with six different lower extremity postures (2 trunk-thigh angles (90° and 135°) × 3 knee angles (45°, 90° and 180°)) (5 replication). Each sitting trials continued for 10 seconds without any request or restriction on the trunk posture. The body kinematics was measured with a motion capture system including the lumbar flexion angle, the pelvic flexion angle, the head flexion angle, and the rounded shoulder angle. Results: Significant effects of the trunk-thigh angle and the knee angle on all dependent measures were observed. First, the bigger trunk-thigh angle (135°) showed better lumbar lordosis, smaller head flexion angle, and less rounded shoulder, suggesting the bigger the trunk-thigh angle, the better the whole trunk postures. Second, the bigger knee flexion angle (180°) negatively influenced on all trunk posture measures, suggesting that the extended knee joint tightens hamstring muscles and pulls the pelvis backward, and finally results in the bad trunk posture such as less lordotic lumbar and thoracic postures, more head flexion angle and more rounded shoulder angle. Conclusion: All dependent variables capturing trunk kinematics clearly denoted the significant influence of the lower extremity posture on the low back, upper back, and head postures. Application: The office chair should be designed under the consideration of the lower extremity postures such as the position of foots, the knee supporter, and the seat inclination angle.

Formations of unexpected chloro-bridged bis(macrocycle) dicopper(II) complexes via decomposition of dichloromethane as a source of chloro-ligands

Kim, Seulgi,Kang, Dong Hee,Ju, Huiyeong,Lee, Eunji,Jung, Jong Hwa,Lee, Shim Sung,Choi, Kyu Seong,Park, In-Hyeok Elsevier Sequoia [etc.] 2018 Inorganica chimica acta Vol.478 No.-

<P><B>Abstract</B></P> <P>The 20-membered N<SUB>3</SUB>O<SUB>2</SUB>-macrocycle <B>L</B> reacts with copper(II) salts (NO<SUB>3</SUB>, ClO<SUB>4</SUB>) in dichloromethane/methanol to yield unexpected isostructural chloro-bridged dinuclear bis(macrocycle) copper(II) complexes of type [<B>L</B>Cu<SUP>II</SUP>-(μ-Cl)<SUB>2</SUB>-Cu<SUP>II</SUP> <B>L</B>]X<SUB>2</SUB> (<B>1</B>: X = NO<SUB>3</SUB>, <B>2</B>: X = ClO<SUB>4</SUB>). Each complex contains two five-coordinate copper(II) ions which are bridged by two chloro-ligands, (μ-Cl)<SUB>2</SUB>, and the remaining coordination sites are completed by three nitrogens from the macrocycle. Notably, the chloro-bridging ligands are derived from the partial decomposition of the dichloromethane solvent molecules. Analogous reaction employing copper(I) chloride also afforded a similar dimer complex, [<B>L</B>Cu<SUP>II</SUP>-(μ-Cl)<SUB>2</SUB>-Cu<SUP>II</SUP> <B>L</B>]Cl<SUB>2</SUB> (<B>3</B>), suggesting such type of the chloro-bridged dicopper(II) complexes are thermodynamically stable under the reaction conditions employed in this work. Considering the τ values (0.45–0.52) for the five-coordinated copper(II) centers, complexes <B>1</B>–<B>3</B> present an intermediate geometry between square planar and trigonal bipyramidal arrangements.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chloro-bridged bis(macrocycle) dicopper(II) complexes of an N<SUB>3</SUB>O<SUB>2</SUB>-macrocycle. </LI> <LI> Chloro-bridging ligand derived from decomposition of dichloromethane solvent. </LI> <LI> Intermediate geometry of copper(II) between SP and TBP. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The N<SUB>3</SUB>O<SUB>2</SUB>-macrocycle <B>L</B> reacts with copper(II) nitrate to afford an unexpected chloro-bridged dicopper(II) complex in which the chloro-ligands are derived from the decomposition of dichloromethane.</P> <P>[DISPLAY OMISSION]</P>

Differentiation of highbush blueberry (Vaccinium corymbosum L.) fruit cultivars by GC-MS-based metabolic profiling

Kim, Da Yeon,Kim, So-Hyun,Ahn, Hye Min,Lim, Sa Rang,Oh, Junsang,Choi, Seulgi,Lee, Hong-Jin,Auh, Joong-Hyuck,Choi, Hyung-Kyoon The Korean Society for Applied Biological Chemistr 2015 Applied Biological Chemistry (Appl Biol Chem) Vol.58 No.1

Highbush blueberries (Vaccinium corymbosum L.) are cultivated worldwide for their fruit with unique taste and potential health benefits. Blueray, Bluecrop, and Spartan are prominent among the various blueberry cultivars. We performed gas chromatography-mass spectrometry (GC-MS)-based metabolic profiling to differentiate the fruits of these three cultivars, and built an optimal partial least squares-discriminant analysis (PLS-DA) model to separate them. Amino acids, fatty acids, organic acids, phenolic compounds, and sugars were identified in the fruits. The optimized PLS-DA model for different cultivars of the fruits was obtained by selecting variables based on a variable importance in the projection (VIP) cut-off value of 1.0. Caffeic acid, aspartic acid, acetic acid, threonolactone, inositol, xylose, glucoside, linolenic acid, mannose, altrose, glycine alanine, and valine were found to be relevant and contributing compounds for differentiating cultivars. In addition, a hierarchical cluster analyses dendrogram pattern was correlated with the PLS-DA. This study suggested that GC-MS-based metabolic profiling coupled with multivariate statistical analysis could be used to differentiate the fruits of three major highbush blueberry cultivars.

Characterization of HPMC/ Gellan Gum Composite for Osteogenic Differentiation of Mesenchymal Stem Cells

Seulgi KIM,Soonjo KWON 한국생물공학회 2018 한국생물공학회 학술대회 Vol.2018 No.10