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Yubin Kim,Kihwan Kim,Seungcheol Ryu,Hojun Cha,Seokho Kim 한국초전도저온학회 2024 한국초전도저온공학회논문지 Vol.26 No.1
High-temperature superconducting rotors offer advantages in terms of output-to-weight ratio and efficiency compared to conventional phase conduction motors or generators. The rotor can be cooled by conduction cooling, which attaches a cryocooler, and by refrigerant circulation, which uses circulating liquid or gas neon, helium and hydrogen. Recent work has focused on environmental issues and on high-temperature superconducting motors cooled with liquid hydrogen that can be combined with fuel cells. However, to ensure smooth supply and return of the cryogenic cooling fluid, a cryogenic rotational coupling between the rotating and stationary parts is necessary. Additionally, the development of a sealing structure to minimize fluid leakage applicable to the coupling is essential. This study describes the design and performance evaluation of a non-contact sealing method, specifically a labyrinth seal, which avoids power loss and heat load caused by friction in contact sealing structures. The seal design incorporates a spiral flow path to reduce leakage using centrifugal force, and computational fluid dynamics (CFD) simulations were conducted to analyze the flow path and rotational speed. A performance evaluation device was configured and employed to evaluate the designed seal. The results of this study will be used to develop a cryogenic rotational coupling with supply and return flow paths for cryogenic applications.
Rapid and Automated Quantification of Microalgal Lipids on a Spinning Disc
Kim, Yubin,Jeong, Su-Nam,Kim, Bolam,Kim, Dong-Pyo,Cho, Yoon-Kyoung American Chemical Society 2015 ANALYTICAL CHEMISTRY - Vol.87 No.15
<P>We have developed a fully integrated centrifugal microfluidic device for rapid on-site quantification of lipids from microalgal samples. The fully automated serial process involving cell sedimentation and lysis, liquid–liquid extraction, and colorimetric detection of lipid contents was accomplished within 13 min using a lab-on-a-disc. The presented organic solvent-tolerable (for <I>n</I>-hexane, ethanol) microfluidic disc was newly fabricated by combining thermal fusion bonding and carbon dot-based valving techniques. It is expected that this novel platform will possibly contribute toward sustainable biofuel applications by providing a practical solution for on-site monitoring of lipid accumulation in microalgal samples, thus providing imperative contribution toward energy and environmental purposes of centrifugal microfluidic technology.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2015/ancham.2015.87.issue-15/acs.analchem.5b01570/production/images/medium/ac-2015-01570q_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac5b01570'>ACS Electronic Supporting Info</A></P>
액체질소 직접분사 냉각방식 mRNA 백신 극저온 저장용기 제작
김기환(Kihwan kim),문정민(Jeongmin Mun),김한영(Hanyoung Kim),김유빈(Yubin Kim),백정현(Jeonghyeon Baek),김석호(Seokho Kim) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.05
In particular, as the mRNA vaccine becomes a major preventive vaccine in the case of COVID-19, the transportation method is being studied to meet global demand. For example, recently developed as a COVID-19 vaccine, Pfizer vaccines should be stored in the temperature range of -70℃, and similar vaccines should also be stored a -30 ℃ or below. However, existing cold storage systems are too high cost to apply storage systems below -30 ℃ and are difficult to apply in transportation. In this study, storage of direct injection using liquid nitrogen was manufactured and maintaining temperature of demanded target. In addition, vaccine storage containers were designed with considering thermal insulation, manufactured, and performance evaluations were implemented.
Visible light photoredox-catalyzed phosphorylation of quinoxalin-2(1<i>H</i>)-ones
Kim, Yubin,Kim, Dae Young Elsevier 2018 Tetrahedron letters: the international organ for t Vol.59 No.25
<P><B>Abstract</B></P> <P>A visible light photoredox-catalyzed C-3 phosphorylation of quinoxalin-2(1<I>H</I>)-ones with diphenylphosphine oxide has been developed. The reaction was effectively accelerated using an inexpensive eosin B as a photoredox catalyst under ambient air at room temperature without any other metal, oxidant, or additive. This approach offers a facile way to prepare 3-diphenylphosphorylated quinoxalin-2(1<I>H</I>)-one derivatives.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The first photoredox-catalyzed phosphorylation of quinoxalin-2(1<I>H</I>)-ones. </LI> <LI> Convenient reaction protocol devoid of the use of metal catalyst and additives. </LI> <LI> This protocol provided the compound in high yield in short reaction time. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Centrifugal microfluidic system for a fully automated N-fold serial dilution
Kim, Tae-Hyeong,Kim, Chi-Ju,Kim, Yubin,Cho, Yoon-Kyoung Elsevier 2018 Sensors and actuators. B Chemical Vol.256 No.-
<P><B>Abstract</B></P> <P>We present an innovative tool for a fully automated N-fold serial dilution with a choice of N=2, 5, 10 on a centrifugal microfluidic device. Individually addressable, reversible diaphragm valves are integrated on the disc for the automatic control of the fluidic transfer. Two metering zones are designed with three microfluidic chambers with the volume of 1μL, 3μL and 5μL to meter the samples or the dilution buffer. The pre-programmed operation of the valves enabled the automatic serial dilution with the choice of the dilution factor of 2, 5, or 10 at each dilution steps. The samples prepared on the disc with various serial dilution factor showed excellent accuracy (R<SUP>2</SUP> >0.970). The automatic serial dilution disc could be an essential tool in the laboratory to replace the time-consuming and iterative pipetting especially when the sample volume is limited.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Serial dilution is fully integrated and automated on a centrifugal microfluidic system. </LI> <LI> Individually addressable, reversible diaphragm valves are utilized to enable the automatic control of the fluidic transfer and metering of the liquid. </LI> <LI> N-fold serial dilution was performed automatically with a choice of N=2, 5, 10. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>N-fold serial dilution is fully automated on a centrifugal microfluidic system with a choice of N=2, 5, 10.</P> <P>[DISPLAY OMISSION]</P>
Antifungal activities of β-thujaplicin originated in Chamaecyparis obtusa
( Yubin Kwon ),( Hyun-sang Kim ),( Hyun-woo Kim ),( Dong Woon Lee ),( Yong-hwa Choi ) 한국응용생명화학회(구 한국농화학회) 2017 Journal of Applied Biological Chemistry (J. Appl. Vol.60 No.3
Environment-friendly, commercially-available agricultural products were investigated for antimicrobial activity against Sclerotinia sclerotiorum, as a pathogen of sclerotium disease. Then β-thujaplicin from Chamaecyparis obtuse was investigated for antifungal activity against six kinds of pathogenic fungi. It showed a statistically significant (p <0.001) growth inhibition effect on Sclerotinia sclerotiorum as a pathogen of sclerotium disease, Rhizoctonia solani AG-4 as a pathogen of damping off, Phytophthora capsici as a pathogen of phytophthora blight, and Colletotrichum coccodes as a pathogen of anthracnose at a concentration of 50 ppm and on Stemphylium solani as a pathogen of spotting disease and Alternaria alternata as a pathogen of black mold at a concentration of 100 ppm. In conclusion, these results indicate that it may be possible to develop environment-friendly agricultural products using β-thujaplicin compounds.
Synthesis of Na-P1 and Analcime-typed Zeolite from Waste Resources
( Yubin Kang ),( Byoungyong Im ),( Jin-ho Yoon ),( Tae Hyung Kim ),( Hyun-woo Shim ),( Basudev Swain ),( Chan Gi Lee ),( Dae Guen Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-
Zeolite is a functional ceramic material having a versatile physiochemical properties and thus has attracted great interest as one of the most classes of environmental fields, for example catalyst, adsorbent and ion exchanger. In recent, it has been known that zeolite has an excellent effect on dehumidification and odor removal. Zeolites are theoretically known to have millions of crystal structures and generally exist in the form of aluminum and silicon polymerized with hydroxyl groups. Therefore, if some waste resources contain aluminum or silicon, they can be considered as candidates of a raw material for synthesis of zeolite. However, the preparation of zeolite along with waste resources is still challenging. In this study, Na-P1 zeolite and analcime-typed zeolite, which are mainly used as heavy metal ion exchangers, were synthesized using waste resources. The aluminum black dross (Al resource) and waste glass powder (Si resource) were used as raw materials of waste resources, which can be generated from the aluminum melting process and the waste LCD panel, respectively. To remove impurities of both raw materials, the acid treatment was carried out with 1 M hydrochloric acid for 2 hrs, and then were pulverized by oscillation mill. The obtained powder was used as a raw material for zeolite synthesis. Here, we applied to hydrothermal process for zeolite synthesis. With control of experimental parameters such as raw material ratio (aluminum black dross : waste glass powder), reaction temperature, and reaction time, it was confirmed that Na-P1 zeolite and analcime-typed zeolite were synthesized and optimum condition for selective synthesis of zeolite was also suggested.