Ether-free polymeric anion exchange materials with extremely low vanadium ion permeability and outstanding cell performance for vanadium redox flow battery (VRFB) application

Cha, Min Suc,Jo, Sang Woo,Han, Seung Hui,Hong, Soo Hyun,So, Soonyong,Kim, Tae-Ho,Oh, Seong-Geun,Hong, Young Taik,Lee, Jang Yong Elsevier 2019 Journal of Power Sources Vol.413 No.-

<P><B>Abstract</B></P> <P>Ether-free poly(<I>p</I>-phenylene)-based anion exchange membrane materials with outstanding vanadium ion blocking properties are reported. The synthesized ionomers with a rigid backbone structure show small dimensional variations despite the high ion exchange capacities. Among the synthesized membranes, the QPPP-2 membrane with ion exchange capacity of 2.1 meq·g<SUP>−1</SUP> exhibits high anion (OH<SUP>−</SUP>, SO<SUB>4</SUB> <SUP>2−</SUP>, and Cl<SUP>−</SUP>) conductivity. The QPPP-2 membrane shows an extremely low diffusion coefficient (2.12 × 10<SUP>−9</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>) for VO<SUP>2+</SUP>, which is much lower than that of Nafion 115 (2.88 × 10<SUP>−6</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>), indicating the vanadium ion blocking property of QPPP-2. Moreover, the chemical and operational stabilities of the membranes are investigated <I>via</I> ex situ soaking tests in 0.1 M VO<SUB>2</SUB> <SUP>+</SUP> solution and in situ operation tests for 100 cycles, respectively. The vanadium redox flow battery single cell assembled with the QPPP-2 membrane exhibits a coulombic efficiency of 99%, voltage efficiency of 87%, and energy efficiency of 86% during 100 cycles at 80 mA cm<SUP>−2</SUP>. The excellent chemical, morphological, and electrochemical properties of the QPPP-2 membrane make it suitable for use in vanadium redox flow battery.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AEMs are fabricated by a Ni(0)-catalyzed cross-coupling reaction. </LI> <LI> The synthesized ionomers indicated excellent dimensional and chemical stability. </LI> <LI> Ether-free polymeric AEMs showed extremely low vanadium ion cross over. </LI> <LI> The performance of developed AEM showed high EE (87%) with high capacity retention. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Dose-linear pharmacokinetics of oleanolic acid after intravenous and oral administration in rats

Jeong, Dong Won,Kim, Young Hoon,Kim, Hui Hyun,Ji, Hye Young,Yoo, Sun Dong,Choi, Won Rack,Lee, Soo Min,Han, Chang-Kyun,Lee, Hye Suk WILEY PUBLISHERS 2007 BIOPHARMACEUTICS AND DRUG DISPOSITION Vol.28 No.2

<P>The pharmacokinetics of oleanolic acid was evaluated in vitro and in vivo. From Caco-2 cell permeation studies, oleanolic acid was a low permeability compound with no directional effects, suggesting a low in vivo absorption mediated by a passive diffusion. Oleanolic acid was metabolically unstable following incubation with rat liver microsomes in the presence of NADPH. After intravenous injection at doses of 0.5, 1 and 2 mg/kg doses, oleanolic acid showed dose-linear pharmacokinetics as evidenced by unaltered CL (28.6–33.0 ml/min/kg), V<SUB>ss</SUB> (437–583 ml/kg), dose-normalized AUC (16.0–17.9 µg min/ml based on 1 mg/kg) and t<SUB>1/2</SUB> (41.9–52.7 min). Following oral administration of oleanolic acid at doses of 10, 25 and 50 mg/kg, T<SUB>max</SUB>, t<SUB>1/2</SUB>, dose-normalized C<SUB>max</SUB> (66–74 ng/ml based on 25 mg/kg) and dose-normalized AUC (5.4–5.9 µg min/ml based on 25 mg/kg) were comparable between 25 and 50 mg/kg dose, but the plasma concentrations at 10 mg/kg dose were not measurable as they were below the limit of quantitation (2 ng/ml). The absolute oral bioavailability was 0.7% for oral doses of 25 and 50 mg/kg. The extent of urinary excretion was minimal for both i.v. and oral doses. The very low oral bioavailability of oleanolic acid could be due to a poor absorption and extensive metabolic clearance. Copyright © 2007 John Wiley & Sons, Ltd.</P>

Acaricidal target and mite indicator as color alteration using 3,7-dimethyl-2,6-octadienal and its derivatives derived from Melissa officinalis leaves

Min?Seung Kang,Hui-Ju Kim,Jun-Hwan Park,Hoi-Seon Lee 한국농약과학회 2018 한국농약과학회 학술발표대회 논문집 Vol.2018 No.4

심인성 색전 요인이 없는 뇌경색 환자에서 경식도 심초음파와 Acoustic Quantification을 이용한 대동맥 탄성의 평가

이종민,윤호중,임효영,박지원,김휘열,전희경,문건웅,정욱성,채장성,김재형,최규보,홍순조 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.8

산유체모델에 의한 Building downwash 현상 해석

구윤서,최상민,이진호,윤희영 안양대학교 산업기술연구소 2000 自然科學硏究 Vol.7 No.-

본 연구에서는 굴뚝주변에 위치한 건물에 의한 세류현상을 보다 정확히 모사하기 위해서 전산유체모델을 이용하였다. 계산 신뢰도를 검증하기 위해서 전산모델 계산치와 1993년 Thompson의 추적자 실험에 의한 실측치 및 대기 환경영향평가에 많이 사용되는 ISCST3 모델 계산치와 각각 비교하였다. ISCST3에서는 건물의 영향을 고려하기 위하여 BPIP을 이용, 건물의 높이와 폭을 결정하여 모델링을 수행하였다. 전산유체모델에서는 건물을 형상화시키고 굴뚝에서 오염물질을 배출시켜 확산 계산을 하였다. 전산유체모델로 모사한 결과, 건물의 후면에 wake가 발생하는 것을 볼 수 있었고, wake zone의 길이는 건물 높이의 약 2배가 되었다. 오염물질 농도를 비교한 결과 ISCST에서는 최대 농도값과 착지점이 일치하지 않았으나, 전산유체모델로 계산한 결과는 추적자 실험치와 거의 일치한 값을 나타냈다. This study used the computational fluid dynamic(CFD) for describing a dispersion influenced by building downwash. We compared calculated concentrations with Thompson's tracer experiment and ISCST3 models. In calculating ISCST3 model, BPIP(Building Profile Input Program) was used to estimate building heights & widths corresponding to a specific wind direction. Results show that ISCST3 model is not appropriate to describe the building downwash but CFD model, which calculates the flow fields and dispersions simultaneously, is in good agreement with tracer measurements. In order to describe the dispersion induced by building wake near the stack, it is recommended to use CFD model.

Evaluating the Degree of Macrodispersion of Carbon Nanotubes using UV-VIS-NIR Absorption Spectroscopy

Ki-Kang Kim,Soo-Min Kim,Yan Cui,Mun-Seok Jeong,Jong-Hun Han,Young-Chul Choi,Kay-Hyeok An,Kyung-Hui Oh,Young-Hee Lee 한국탄소학회 2009 Carbon Letters Vol.10 No.1

We measured the degree of macrodispersion of the various single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) using UV-VIS-NIR absorption spectroscopy. CNTs were dispersed with SDS of 2 wt % in deionized water using the homogenizer and then were further centrifugated at 6000 g for 10 min. The degree of macrodispersion, expressed by Dm(λ)=Aa(λ)/Ab(λ)*100 (%), where λ is the wavelength and Aa(λ) and Ab(λ) are the absorbance of the sample after and before centrifugation, respectively. In the case of MWCNTs, we evaluated the degree of macrodispersion by the average degree of macrodispersion (Dm(λ)) between 1000 and 1200 nm. The degree of macrodispersion of SWCNTs was evaluated at the wavelength in which van Hove singularity-related transition regions were excluded, i.e., the range was chosen between E11S and E22S peaks. We have estimated six samples with the same method. The standard deviation of each sample was lower than 5. Therefore, we presented a reliable evaluation method for the macrodispersion of CNTs for standardization.

한국의 정상 성인과 만성신부전 환자에서 신피질 두께의 측정

봉정민 ( Bong Jeong Min ),이현희 ( Lee Hyeon Hui ),이준승 ( Lee Jun Seung ),정우경 ( Jeong U Gyeong ),이종호 ( Lee Jong Ho ),양달모 ( Yang Dal Mo ) 대한신장학회 2003 Kidney Research and Clinical Practice Vol.22 No.5

배 경 : 신피질 두께는 다양한 선장 질환의 진단에 유용하게 이용되고 있으나 정상 수치에 대해서는 잘 알려져 있지 않다. 이에 초음파로 한국의 정상 성인과 신대체 요법 시행 전의 만성신부전 환자에서 신피질의 두께를 측정하여 정상수치를 확인하고, 비가역적인 신부전 상태와 구별되는 신피질의 두께를 제시할 수 있는지 알아보고자 하였다. 방 법 : 건강 검진에서 이상이 없는 243명의 성인과 혈중 크례아티닌이 4 ㎎/dL 이하인 57명의 만성신부전 환자에서 초음파로 신피질의 두께를 측정 하였고, 만성신부전 환자들은 Cockcroft-Gault 공식을 이용하여 크레아티닌 청소율을 계산하였다. 결 과 : 정상 성인에서 신피질의 두께가 남자는 0.74±0.15 ㎝, 여자는 0.69±0.13 ㎝로 남자의 평균치가 컸고 (p<0.005), 좌우로 나누어 보면 좌측이 0.76±0.14 ㎝, 우측이 0.67±0.13 ㎝로 좌측의 평균치가 컸으며 (p<0.005), 남녀와 좌우 구분 없이 계산하면 0.72±0.14 ㎝로 측정되었다. 만성신부전 환자를 당뇨군과 비당뇨군으로 나누어 비교할 때 신피질 두께의 차이는 없었고, 비당뇨군 환자를 크레아티닌 청소율 (Ccr) 30 mL/min을 기준으로 나누어 비교하면 <30 mL/min는 0.630.10 ㎝>30 mL/min는 0.79±0.11 ㎝로 차이를 보였다 (p<0.001). 결 론 : 한국 정상 성인에서 신피질의 두께는 평균 0.72±0.14 ㎝ (0.41-1.25)로 측정되었고, 신부전 환자에서 대략 0.72 ㎝를 경계로 Ccr 30 mL/min 전후가 구분되어짐을 알 수 있었으나, 정상 수치의 범위가 넓고 크레아티닌 청소율이 30 mL/min 이상인 신부전 상태에서는 신피질의 두께가 정상 수치를 보이므로, 신부전 환자의 진단 및 치료를 결정할 때에는 임상적인 상황과 신장 조직 검사 같은 침습적 방법을 고려해야 한다. Background : The thickness of the renal cortex is useful in all aspects of nephrology but no normal range has been established. Therefore, we investigated the renal cortex thickness by ultrasonography in normal Korean adults and chronic renal failure (CRF) patients before renal replacement therapy. For the purpose of evaluating the normal range then, we are going to predict the threshold range of cortex thickness in irreversible renal failure status. Methods : In 243 healthy Korean adults and 57 CRF patients with the creatinine level, ≤4 mg/dL were measured the renal cortex thickness. Creatinine clearance was calculated on the basis of the Cock-croft-Gault formula. Results : In normal adults, the difference between male and female was 0.74±0.15 cm, 0.69±0.13 cm respectively, male was greater than female (p<0.005) and the average value of the left and right renal cortex thickness was 0.76±0.14 cm, 0.67±0.13 cm, the left kidney was greater than right one (p<0.005). The combined average value of the left and right renal cortex was 0.72±0.14 cm. In CRF patients, There was no difference of cortex thickness between diabetes patients and non diabetes but in non diabetes patients, the difference between Ccr <30 mL/min and Ccr ≥30 mL/min was 0.63±0.10 cm, 0.79±0.11 cm (p<0.00l). Conclusion : The overall mean of cortex thickness in korean normal adults was 0.72±0.14 cm (0.41-1.25) and approximately, a threshold of 0.72 cm was identified for the cortex thickness that allowed us to distinguish Ccr <30 mL/min from Ccr ≥30 mL/min in CRF patients. But the cortex thickness alone is not a sufficient marker to predict reversibility. We should consider other invasive procedure such as kidney biopsy.

원발성 폐암 환자의 혈청에서 DAP kinase 유전자의 Methylation 양상

이준희 ( Lee Jun Hui ),이정욱 ( Lee Jeong Ug ),정경식 ( Jeong Gyeong Sig ),김기욱 ( Kim Gi Ug ),이태근 ( Lee Tae Geun ),이경우 ( Lee Gyeong U ),나민아 ( Na Min A ),전두수 ( Jeon Du Su ),최영민 ( Choe Yeong Min ),김윤성 ( Kim Yun S 대한결핵 및 호흡기학회 2003 Tuberculosis and Respiratory Diseases Vol.55 No.4

Combustion Characterization according to Accelerated Deterioration Temperature of a Non-class 1E Cable

Seok Hui Lee,Min Ho Kim,Seung Yeon Jeong,Sang Kyu Lee,Ju Eun Lee,Min Chul Lee 한국화재소방학회 2022 International Journal of Fire Science and Engineer Vol.36 No.1

In this study, the temperature effect of accelerated deterioration on combustion characteristics was investigated when accelerating aging a non-class 1E cable for nuclear power plants. The accelerated aging of 40 years was conducted under five temperature conditions of 90 °C, 100 °C, 110 °C, 130 °C and 150 °C. In the early period of combustion when the first peak of the heat release rate emerged, the heat release of the non-aged cable exhibited the largest peak value of 225 kW/㎡ while the heat release of the aged cables exhibited a comparatively low first peak value. The first peaks of aged cables decreased as the temperature condition increased. This tendency is considered to emerge from the thermal decomposition and destabilization of long-chained polymer structure when the sheath and insulation of cables are exposed to a thermal degradation environment. Hence, this loosening of the chemical bond and its decomposition severely affected the degradation of the flame retardant performance. In particular, in the combustion characteristics for the aged cables under temperature conditions of 100 °C or higher, the first peak value of the heat release rate did not exceed 200 kW/㎡. In the middle period of combustion, the heat release rates of both the non-aged and the aged cables were kept constant at approximately 25-30 kW/㎡ without significant change. In the later period of combustion, the second heat release peaks emerged for only non-aged, 90 °C and 100 °C cables because the cables aged under low temperature conditions (90 °C and 100 °C) maintained a certain level of flame retardant performance while those aged above 100 °C did not. Therefore, it can be considered that the higher accelerated deterioration temperature triggers the higher degradation of the flame retardant performance, and 100 °C is a critical temperature that involves the significant degradation effect.

원자력발전소용 안전등급 케이블의 경년열화에 따른 연소 및 연기특성 분석

이석희(Seok-Hui Lee),김민호(Min-Ho Kim),이상규(Sangkyu Lee),이주은(Ju-Eun Lee),이민철(Min-Chul Lee) 한국화재소방학회 2021 한국화재소방학회논문지 Vol.35 No.1

본 연구에서는 원자력 발전소에서 사용되는 안전등급 케이블을 대상으로 경년열화에 따른 연소 및 연기특성을콘 칼로리미터 시험을 통해 분석하였다. 열발생률의 1st peak 구간인 초기 특성의 경우, 비열화 케이블이 열화 케이블에 비해 20-50 kW/㎡ 높게 측정되었으나, 2nd peak인 중/후기에는 열화에 따른 난연성능의 저하에 기인하여 비열화케이블에 비해 열화 케이블들이 높게 측정되었다. 또한, Char 층이 불안정하게 형성됨에 따라 char 층의 유지시간이비열화 케이블에 비해 열화 케이블들이 약 200 s 단축됨을 확인하였다. 총발열량은 열화 케이블이 비열화 케이블에비해 약 1.4배 높게 측정되었다. 연기특성의 경우, 연기발생률은 열발생률과, 총 연기발생량은 총발열량과 비슷한 양상을 띄며, 총 연기발생량은 열화 케이블이 비열화 케이블보다 높게 측정되었다. 연기인자는 열화 기간이 증가함에따라 증가하는 경향성을 보였으며, 4년 이상 열화된 케이블들은 비열화 케이블에 비해 약 1.76-2.0배 정도 차이가 났다. 따라서 경년열화가 진행된 케이블일수록 열 및 연기방출의 위험성이 증가하였다. In this study, combustion and smoke characteristics according to the aging of class 1E cables in nuclear power plants wereanalyzed through a cone calorimeter test. In the case of combustion characteristics, during the early period, which was thefirst peak of the heat release rate, the peak value of the non-aged cable was higher by approximately 20-50 kW/㎡ than thatof aged cables. However, in the mid-late periods, which was the second peak, the value of the aged cables were higher thanthe non-aged cable due to the decrease in flame retardant performance with aging deterioration. In addition, the duration ofthe char layer of the aged cables was shortened by 200 s than that of the non-aged cables due to the unstable formation ofchar layer. The total heat release measured was approximately 1.4 times higher in the aged cables than in the non-aged cables. In the case of smoke characteristics, the smoke production rate and total smoke release show a similar trend with the heatrelease rate and total heat release. The total smoke release of the aged cables was measured to be higher than that of thenon-aged cables. The tendency of the smoke factor increased with aging deterioration, and the values of the smoke factor inthe aged cables beyond 4 years were approximately 1.76-2.0 times different from those in the non-aged cables. Consequently,the smoke risk increased with aging deterioration. Therefore, the risk of heat and smoke release increased as aging progressed.