http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Thermal and Electrical Analysis of Coated Conductor Under AC Over-Current
Kwanwoo Nam,Chanjoo Lee,Dong Keun Park,Tae Kuk Ko,Bok-Yeol Seok IEEE 2007 IEEE transactions on applied superconductivity Vol.17 No.2
<P>In order to design a high temperature superconducting (HTS) winding for the fault current limiter (FCL), the resistance and the temperature of the winding should be calculated quantitatively under the over-current caused by fault condition. In this paper, a transient analysis is performed to estimate the resistance development and the temperature rise of coated conductor (CC) under AC over-current. A one-dimensional thermal conduction model with an electrical circuit model is developed for the solenoid coil configuration at 65 K cooling condition. All the composite materials except the buffer layer in CC are considered in the model. Two kinds of stabilizer materials (copper/stainless steel) are considered to investigate the current limitation of CC. The simulation results are compared with the experimental data of the commercial CC. The effect of Ag and solder layer on the simulation result are revealed for CC.</P>
Kwanwoo Kim,Jaehyun Wie,Jooheon Kim 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.83 No.-
It is extremely advisable but challenging to develop cathodic catalyst for efficiently catalyzing the oxygenreduction reaction (ORR) in energy storage and conversion system. Nitrogen (N) and phosphorus (P) co-doped porous carbon (C) materials have been prepared as a non-precious metal catalyst. This synthesis wasachieved through pyrolysis of ethylenediaminetetraacetic acid, triphenylphosphine, melamine andCoCl2 6H2 O mixture. The resulting material was capable of efficiently charge transfer via the coordinationbond of cobalt (Co) and EDTA, that makes octahedral structure. In addition, redistribution of charge occurreddue to co-doping of the N and P, which is advantageous for the oxygen reduction reaction (ORR). The as-prepared N and P co-doped mesoporous carbon (NPMPC) was characterized by a high average porosityand ahigh specific surface area. Furthermore, the NPMPC had a positive effect on ORR by allowing triple phases(gas-liquid-solid) to coexist in a wide range. We have successfully fabricated electrochemical catalysts thathave not been reported previously. The electrocatalytic activity of NPMPC-0.6 (E onset:-0.08 V & Ehalf-wave:-0.136 V)for ORR in alkalinemediawasbetterthanPt/C(Eonset:-0.037 V &Ehalf-wave:-0.122 V).Overall,NPMPC-0.6 showed high efficiency and improved performance for oxygen reduction reaction.
Antioxidant and Anti-aging Potential of a Peptide Formulation (Gal2-Pep) Conjugated with Gallic Acid
Kwanwoo KIM,Hoomin LEE,Sheik ALIYA,Hyoung-Shik KIM,Vivek K. BAJPAI,Yun Suk HUH 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Skin is highly vulnerable to premature aging due to external stress, therefore, in this study, a peptide formulation, (galloyl)2-KTPPTTP (Gal2-Pep) was synthesized by combining TPPTTP peptide, and gallic acid (GA). All peptides were synthesized on 2-chlorotrityl chloride resin using solid-phase peptide synthesis (SPPS), and analyzed on an electrospray ionization (ESI)/quadrupole-time-of-flight (Q-TOF) tandem mass spectroscopy (MS) system. Initially, Gal2-Pep showed no toxicity below the concentration 100 μM with cell survival rate of 88% for keratinocytes and fibroblasts. The reactive oxygen species (ROS) scavenging activity of Gal2-Pep was more stable compared to GA alone; and after four weeks at room temperature, its ROS scavenging activity remained higher than 50%. Moreover, the peptide formulation, Gal2-Pep also exhibited elastase inhibitory effect in CCD-1064Sk fibroblast cells. Based on the results of RT-qPCR, it was proved in this study that Gal2-Pep increased the expression of PGC-1α to prevent oxidative stress, and validated its potential as an anti-aging agent through increasing the expression of type I collagen and by decreasing the expression of matrix metalloproteinase-1 (MMP1). The findings obtained reinforce the suggestion that the peptide formulation synthesized in this study could be used as a natural antioxidant and anti-aging agent for its cosmetic applications.
Flow analysis and test for ITER thermal shield components
Nam, Kwanwoo,Lim, Kisuk,Kang, Dongkwon Elsevier 2018 Fusion engineering and design Vol.136 No.1
<P><B>Abstract</B></P> <P>Flow distribution on the piping network of ITER Thermal Shield (TS) is analyzed and orifice installation is suggested for attenuating flow mal-distribution. Flow test is performed for a TS segment to verify the analysis model. Room temperature nitrogen gas passes through the cooling pipe on TS segment with test flow rate which is equivalent to the actual operating condition of TS. Flow rate is controlled by a thermal mass flow controller and pressure drop between the inlet and the outlet of the pipe routing is measured by a differential pressure gauge. Test result is compared with the analysis one to check the validity of the analysis model for the real manufactured TS segment. The flow test is also conducted for the fabricated orifices. The loss coefficient of the orifice is compared with that used in the analysis. The loss coefficient correlation for the fabricated orifices is obtained from the test results.</P>