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>

Crosslinked anion exchange membranes with primary diamine-based crosslinkers for vanadium redox flow battery application

Cha, Min Suc,Jeong, Hwan Yeop,Shin, Hee Young,Hong, Soo Hyun,Kim, Tae-Ho,Oh, Seong-Geun,Lee, Jang Yong,Hong, Young Taik Elsevier 2017 Journal of Power Sources Vol.363 No.-

<P><B>Abstract</B></P> <P>A series of polysulfone-based crosslinked anion exchange membranes (AEMs) with primary diamine-based crosslinkers has been prepared via simple a crosslinking process as low-cost and durable membranes for vanadium redox flow batteries (VRFBs). Chloromethylated polysulfone is used as a precursor polymer for crosslinked AEMs (CAPSU-x) with different degrees of crosslinking. Among the developed AEMs, CAPSU-2.5 shows outstanding dimensional stability and anion (Cl<SUP>−</SUP>, SO<SUB>4</SUB> <SUP>2−</SUP>, and OH<SUP>−</SUP>) conductivity. Moreover, CAPSU-2.5 exhibits much lower vanadium ion permeability (2.72 × 10<SUP>−8</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>) than Nafion 115 (2.88 × 10<SUP>−6</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>), which results in an excellent coulombic efficiency of 100%. The chemical and operational stabilities of the membranes have been investigated via 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 excellent chemical, physical, and electrochemical properties of the CAPSU-2.5 membrane make it suitable for use in VRFBs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The crosslinking between polymer chains are constructed by 4,4′-diaminobenzophenone. </LI> <LI> The crosslinked AEMs were fabricated by commercial polysulfone (PSU; Udel<SUP>®</SUP> P-3500). </LI> <LI> The crosslinked AEM based on PSU indicated good chemical and dimensional stability. </LI> <LI> The performance of crosslinked AEM showed high EE (86%) with high capacity retention. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

優秀工業系 實科敎員養成을 위한 工業敎育大學 敎育課程 改善에 關한 硏究 : 工業敎育學部를 中心으로

李廷玟,任洪彬,李載元,李來然,金澤基,劉承坤 충남대학교 공업교육연구소 1983 論文集 Vol.6 No.2(A)

This paper is studied to improve the curriculum of the College of Industrial Education of Chungnam National University, which is more helpful for the students to become a competent teacher of technical high school. The thesis includes the curriculum of general, professional, technical subjects and so on. The main conclusions are summarized as follows; 1) The current curriculum of the College of Industrial Education was formed on a wholesale manner following the basis of standard courses for some characterized engineering colleges. But the suggested is conformed to the curriculum system of CNU in credits and hours. 2) The current technical subjects are mainly based on the curriculum of college of engineering, but the newly suggested technical subjects are conformed to the curriculum of technical high school as following that some departments of engineering are founded in the College of Industrial Education. 3) In current curriculum, the ratio of reguired technical subjects to elective technical subjects is 85:15. In suggested curriculum, the ratio of it is largely changed to 45:55 for effective operation of minor cousres. And the lists of the subjects for minor courses are changed from subjects for College of Science to subjects for College of Engineering.

Aspergillus oryzae를 이용한 쌀과 콩 고오지 제조중의 성분과 효소활성의 변화

이택수,이선민 서울여자대학교 자연과학연구소 2003 자연과학연구논문집 Vol.15 No.-

쌀, 콩, 쌀과 콩의 흔용원료에 Aspergillus oryzae의 단모균 (A균주)과 장모균 (B균주)을 접종하여 만든 고오지 제조과정 중의 성분, 효소력 및 고오지 소화액의 성분을 분석한 결과는 다음과 같다. 고오지의 pH는 5.80-7.93 의 범위로 제국 초기보다 후기에 다소 상승되었으며 기질별로는 콩, 쌀, 쌀과콩의 혼용고오지의 순으로 pH가 높았다. 적정산도는 0.22-3.57 ml (0.1N NaOH)의 범위로 72시간까지 증가하는 경향이었다. 단모균은 장모균의 고오지보다 적정산도가 높은 편이고 기질별로는 쌀과 콩의 흔용고오지에서 높게 나타났다. 액화와 당화 amylase의 활성은 최대활성기인 48-72시간에 콩 단용 고오지에서 가장 낮았고 쌀, 쌀과 콩의 혼용 고오지에서는 활성이 비슷하였다. 액화와 당화 amylase의 활성은 단모균보다 장모균 사용의 고오지에서 높았다. 고오지의 산성 및 중성 protease활성은 72시간에 최 대활성을 보였고 이 시기에 콩, 쌀과 콩, 쌀 고오지의 순으로 활성 이 높았다. 중성 protease는 콩, 산성 protease는 쌀 고오지에서 각각 높은 경향을 보였고, 단모균은 장모균의 고오지 보다 산성 및 중성 protease활성이 높았다 Cellulase활성은 48-72시간에 최대활성을 보였고 단모균과 장모균의 활성차이는 불명확하였으나 장모균 사용 시 콩단용 고오지에서 활성도가 낮았다. 고오지 소화액의 성분 중 총질소와 아미노태질소는 단모균 사용의 콩고오지에서, 환원당은 장모균 사용의 쌀 고오지에서 각각 높게 나타났다. ◁표 삽입▷(원문을 참조하세요) We analyzed the components, enzymatic activities and the compositions of auto-digested products of the Koji prepared with rice, soy bean, and the mixture of rice and soy bean, in which each was inoculated with Aspergillus oryzse which had short-mycelium (A strain) or long-mycelium (B strain). The pH of Koji was in the range of 5.80-7.93, increased a little in the later period, and it was exhibited the higher value of pH in the order of soy bean, rice and the mixture Koji, The titrable acidities were 0.22-3. 57ml (0.1N NaOH) and shown to have tendency to be increased with time to the period of 72 hours. The titrable acidity of Koji with short mycelium was higher than that of the Koji with long mycelium. And the acidity of the Koji with mixture of rice and soy bean was higher with respect to substrate. Liquefying and saccharifying amylase activities were lower in the soy bean Koji in 48-72 hours, which was the maximal activated period. But the activities were shown similar in the Kojis with rice and mixture of rice and soy bean. Both activities were higher in the Koji with long mycelium than with short mycelium. The acidic and neutral protease activities of Koji was observed to be maximal at 72 hours in order of soy bean, mixture of rice and soy bean, and rice Koji, The neutral protease had tendency to be shown to be high activity in the soy bean Koji, and acidic activity was high in the rice Koji, The Koji with short mycelium had higher activities than that with long mycelium in acidic and neutral protease activities. The cellulase activity was maximal in period of 48-72 hours and the difference in activity was not evident in the Koji with short mycelium and with long mycelium. However, the activity was lower in the soy bean Koii when long mycelium was used. The total and amino nitrogen of component of auto-digested Koji was highest in the soy bean Koji when short myceliumed Aspergillus oryzse was used, and the content of reducing sugar was highest in the rice Koji when long myceliumed Aspergillus oryzse was used.

볶은쌀과 탈지대두를 첨가하여 담금한 탁주의 품질특성

이선민,이택수 서울여자대학교 자연과학연구소 2000 자연과학연구논문집 Vol.12 No.-

The characteristics of mash qualities of Takju prepared by using defatted soybean or roasted rice with steamed rice as a control were investigated during fermentation. Maximum ethanol content (9.8∼10.4%) was found after 6∼10 days of fermentation. There was no difference of ethanol content among three treatments. pH of Takju showed 3.51∼3.67 after 14 days of fermentation and total acid of Takju by using defatted soybean were 1.51∼1.95% after 2∼8 days of fermentation. At the beginning of fermentation, reducing sugar content was in the range of 2.37∼2.92%, thereafter it was rapidly decreased. Hunter L-value of control was high while Hunter a-value of Takju by using roasted rice was high. Organic acids in mash of Takju showed 12.5∼444.9mg/100ml lactic acid, 5.2 ∼34.2/100ml succinic acid, 0∼16.8mg/100ml citric acid, 0∼22.1mg/100ml malic acid and 1.5∼22.3mg/100ml acetic acid. Total organic acid and lactic acid in Takju prepared by using defatted soybean was high.

시판된장의 숙성정도 예측을 위한 전자코의 적정조건

양영민,노봉수,이택수 서울여자대학교 자연과학연구소 1997 자연과학연구논문집 Vol.9 No.-

본 연구는 된장의 숙성 정도를 6개의 metal oxide 센서가 내장된 휴대용 전자코를 이용하여 예측하고자 하였다. 15℃에서 숙성시킨 시판된 장은 60일 정도에 감도가 급격히 떨어지기 시작해 그 이후로는 거의 변화가 없으며 15℃에서 숙성하다가 33일부터 25℃로 숙성 온도를 달리 하여 숙성시킨 된장은 38일부터 감응도가 급격히 떨어지기 시작해 그 이후에는 거의 일정하였다. 센서 감응도의 기울기와 상관계수를 비교해 보면 15℃에서 숙성시킨 된장보다 25℃에서 숙성시킨 된장이 센서 감응도 변화량, 상관계수값 모두 크고, 6개의 센서 중에서는 #2, #4이 가장 민감하였다. This study is to predict fermentation time of commercial soybean paste by a electronic nose that has six metal oxide sensors. #2 and #4 sensors were more sensitive to volatile components of soybean paste than any other sensors. The sensitivity of the electronic nose to a commercial soybean paste was rapidly reduced after 60 days at 15℃ and not too much changed thereafter. It was also reduced after 38 days when temperature was changed from 15℃ to 25℃ after 33 days. The correlation between sensitivity of sensor and fermentation time was evaluated. The correlation coefficient and changes of sensitivity at 25℃ was higher than that at 15℃

디스크형 산화구리 촉매담지 세라믹필터의 제조와 물성

홍민선,문수호,이재춘,이동섭,임우택 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.2

A catalyst with CuO ceramic filter for simultaneous treatment of dust and HAP was prepared and characterized. Catalytic ceramic tilter can not only potentially achieve the substantial savings in energy but provide with effective optimization and integration of process for simultaneous removal of S0₂ㆍ NOx and particulates from flue gases. Catalytic ceramic filters remove simultaneously particulates on exterior surface of filters and reduce NO to N₂and H₂O by SCR (Selective Catalytic Reduction) process. Preparation of catalyst impregnated ceramic filter with disk shape (Ψ50) follow the processing of alumino-silicate ceramic filter, support impregnation and catalyst impregnation(copper oxide). Preparation routes of alumino-silicate catalyst carrier suitable for production of catalytic filters practically were studied and developed using the sol-gel and colloidal processing, homogeneous precipitation and impregnation method. Characterization of the catalyst, catalyst carrier catalytic filter materials have been performed the using various techniques such as BET, XRD, TGA, SEM. Combination of the sol-gel and colloidal processing and impregnation method is recommended to prepare catalyst carriers economically for catalytic filter applications.

의과대학 학제 변화에 대응한 의예과 교육 개선 방안

박현,최경민,신창호,정은택,정선관,이상열,박민철 圓光大學校 醫科學硏究所 2005 圓光醫科學 Vol.20 No.2

Bioconversion of ginsenoside Rc into Rd by a novel α-L-arabinofuranosidase, Abf22-3 from Leuconostoc sp. 22-3: cloning, expression, and enzyme characterization.

Liu, Qing-Mei,Jung, Hae-Min,Cui, Chang-Hao,Sung, Bong-Hyun,Kim, Jin-Kwang,Kim, Song-Gun,Lee, Sung-Taik,Kim, Sun-Chang,Im, Wan-Taek N.V. Swets en Zeitlinger 2013 Antonie van Leeuwenhoek Vol.103 No.4

<P>A novel α-L-arabinofuranosidase (Abf22-3) that could biotransform ginsenoside Rc into Rd was obtained from the ginsenoside converting Leuconostoc sp. strain 22-3, isolated from the Korean fermented food kimchi. The gene, termed abf22-3, consisting of 1,527 bp and encoding a protein with a predicted molecular mass of 58,486 Da was cloned into the pMAL-c2x (TEV) vector. A BLAST search using the Abf22-3's amino acid sequence revealed significant homology to that of family 51 glycoside hydrolases. The over-expressed recombinant Abf22-3 in Escherichia coli BL21 (DE3) catalyzed the hydrolysis of the arabinofuranoside moiety attached to the C-20 position of ginsenoside Rc under optimal conditions of pH 6.0 and 30 C. This result indicated that Abf22-3 selectively converts ginsenoside Rc into Rd, but did not catalyze the hydrolysis of glucopyranosyl groups from Rc or other ginsenosides such as Rb1 and Rb2. Over-expressed recombinant enzymes were purified by two steps with amylose-affinity and DEAE-cellulose chromatography and then characterized. The kinetic parameters for α-L-arabinofuranosidase showed apparent Km and Vmax values of 0.95 0.02 μM and 1.2 0.1 μmol min(-1) mg of protein(-1) against p-nitrophenyl-α-L-arabinofuranoside, respectively. Using a purified MBP-Abf22-3 (10 μg/ml), 0.1 % of ginsenoside Rc was completely converted to ginsenoside Rd within 20 min.</P>

식품 및 환경 , 기타 고온 · 호기법에 의한 중화요리잔반의 처리 과정에서의 중 · 고온균의 분리 및 특성

양재경,서용기,최경민,박응로,황기,이성택 ( Jae Kyung Yang,Yong Ki Seo,Kyung Min Choi,Eung Roh Park,Key Whang,Sung Taik Lee ) 한국미생물생명공학회 1997 한국미생물·생명공학회지 Vol.25 No.6