간헐식 흐름방식을 활용한 수직 · 수평 습지의 정화효율 평가

주광진(Kwang Jin Joo),이동민(Dong Min Lee),김기중(Ki Jung Kim),조용철(Yong Chul Cho),장광현(Gwang Hyeon Jang),최이송(I Song Choi),오종민(Jong Min Oh) 응용생태공학회 2017 Ecology and resilient infrastructure Vol.4 No.3

본 연구에서는 부영양화의 원인이 되는 질소와 인의 제거 효율을 향상시킬 목적으로 광물질을 활용한 여재를 이용하여 호기, 혐기의 흐름조건을 만들어주기 위한 수직·수평 흐름 인공습지를 고안하여 아크릴 반응조로 제작한 후 성능평가를 진행하였다. 수직·수평 흐름형 인공습지의 경우 호기 및 혐기조건을 평가하기 위해서 반응조 내 용존산소(DO) 농도를 측정해본 결과 호기상태에서는 2.7 ㎎/L, 혐기상태에서는 N.D로 확인되어 목적에 부합된 결과가 확인되었다. 실험결과에서는 SS 저감효과가 140 min, 80 min, 60 min의 운전시간에서 각각 94%, 91%, 61%의 효율을 보였고, T-P의 경우 각각의 운전시간에 따라 84%, 71%, 63%의 저감효율을 보였다. 또한 T-N의 경우 각각의 운전시간에 따라 63%, 49%, 42%의 저감효율을 보여 기존의 습지가 12~24 hr 체류시간을 가지는 것에 비하여 짧은 운전시간에도 높은 처리효율을 보이는 것으로 확인되었다. 본 연구에서는 수직·수평 흐름 방식을 복합 적용하여 기존 인공습지의 단점을 보완하기 위해 기술개발을 진행한 것으로 어떠한 기능적 효과를 갖는지 확인하였고, 향후 이에 대한 현장적용을 위한 운영 및 관리적 차원의 메커니즘 연구가 추가로 진행 될 필요가 있다. Nitrogen and phosphorus are key factors in causing eutrophication of water body. In this study, ceramics media was selected to increase the removal efficiency of nitrogen and phosphorus. We designed vertical, horizontal flow constructed wetlands to create aerobic and anaerobic flow conditions by using the media, then proceeded to performance evaluations after acrylic reactors were produced. In the case of vertical and horizontal flow constructed wetlands, we measured oxygen concentrations to evaluate aerobic and anaerobic conditions. we got the result of 2.7 ㎎/L in the aerobic condition, N.D in the anaerobic condition respectively, which suited our purpose. The result of the combined vertical and horizontal flow condition showed that the removal efficiency of SS was 94%, 91%, 61% at 140 min, 80 min, 60 min of running times, respectively, and the removal efficiency of T-P was 84%, 71%, 63% during each running time. In case of T-N, the removal efficiency was 63%, 49%, 42% during each running time. We found that the reactor exerted better removal efficiency when in the short time compared to 12 - 24 hr residence time of existing wetlands. In this study, we conducted experiments to explore functional effects after applying combined vertical and horizontal flow methods in the field. Further study will be carried out to identify its mechanism and administrative perspective.

Controlled post-sulfurization process for higher efficiency nontoxic solution-deposited CuIn_0.7Ga_0.3Se₂ absorber thin films with graded bandgaps

Jang, Jin Woo,Lee, Seung Min,Choi, Ik Jin,Cho, Yong Soo ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.710 No.-

<P><B>Abstract</B></P> <P>A practical way of adjusting post-sulfurization process with variable durations is proposed to improve the cell-conversion efficiency of non-toxic solution driven CuIn<SUB>0.7</SUB>Ga<SUB>0.3</SUB>Se<SUB>2</SUB> absorber thin films. The degree of bandgap grading was controllable by changing the sulfurization time from 2 min to 30 min due to the dissimilar distribution of sulfur across the absorber layer. Deeper intensified distributions of Ga and S were responsible for enhancements in the open-circuit voltage and cell-conversion efficiency. A competitive efficiency of ∼8.81% for the 10 min-sulfurized CIGSSe cell was achieved with other promising parameters, i.e., short-circuit current density of 33.17 mA/cm<SUP>2</SUP>, open-circuit voltage of 0.496 V, and fill factor of 53.5%, resulting from the improved carrier collection and reduced recombination by the bandgap grading. This improved efficiency corresponds to a ∼15.6% enhancement compared to the unsulfurized sample.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Controlled post-sulfurization process enhances cell efficiency of CuIn<SUB>0.7</SUB>Ga<SUB>0.3</SUB>Se<SUB>2</SUB>. </LI> <LI> Sulfur penetrates easily toward the back contact with concentration gradient. </LI> <LI> A graded bandgap structure is responsible for the improved charge collection. </LI> <LI> The achieved cell efficiency of ∼8.81% corresponds to the ∼15.6% enhancement. </LI> <LI> Actual bandgap variations are projected on the basis of elemental distributions. </LI> </UL> </P>

반응표면분석법을 이용한 배 퓌레 열수처리 조건 최적화

박민경(Min Kyeong Park),조용식(Yong Sik Cho),장현욱(Hyun Wook Jang) 한국식품영양과학회 2022 한국식품영양과학회지 Vol.51 No.11

본 연구는 열수처리 온도(50, 70, 90°C) 및 열수처리 시간(15, 30, 45분)을 달리하여 배 퓌레를 제조한 후 품질특성을 분석하여 반응표면분석법을 통해 최적의 열수처리 조건을 구하고자 하였고, 중심합성계획법에 따라 총 9가지의 실험점에서 진행하였다. 열수처리 온도 및 시간을 독립변수로 정하고, 품질특성에 관련된 적색도, ΔE값, 일반세균, 대장균군, polyphenol oxidase 활성, 총 폴리페놀 함량, 총 플라보노이드 함량을 종속변수로 설정하였다. 독립변수가 종속변수에 미치는 영향에 대해 분석한 결과, 적색도와 갈변을 나타내는 ΔE값은 각각 -0.38~1.20, 0.97~11.88의 범위로 측정되었고, 반응식의 R2은 각각 0.9754, 0.9818이었다. 일반세균 및 대장균군의 생균수는 각각 0.00~4.91 log CFU/mL, 0.00~4.03 log CFU/mL의 범위였고, 반응식의 R²은 0.9849, 0.9714였다. 갈변의 원인이 되는 polyphenol oxidase 활성은 122.57~235.13 unit 범위였으며, 반응식의 R²은 0.8616의 값을 보였다. 배 퓌레의 유효성분으로 총 폴리페놀 함량 및 총 플라보노이드 함량은 각각 19.33~24.54 GAE mg/100 g, 4.56~5.78 GAE mg/100 g 범위였으며, 이때 반응식의 R²은 각각 0.9181, 0.9097을 나타내었다. 이를 바탕으로 contour map을 superimposing 하여 최적 열수처리 조건을 설정한 결과, 최적화된 열수처리 조건의 온도범위는 69.3~80.4°C, 시간 범위는 16.8~25.8분으로 나타났으며, 최적점은 74.6°C, 20.7분으로 나타났다. 이에 대해 모델의 신뢰성을 검증하기 위해 예측값과 실험값을 비교한 결과, 각 반응변수의 실험값은 모두 예측값의 95% 신뢰구간 및 예측구간 범위에 들어와 모델의 적합성을 확인하였다. This study analyzed the quality characteristics of pear puree by varying the hydrothermal treatment temperature (50, 70, and 90°C) and time (15, 30, and 45 min) and sought to determine the optimal hydrothermal treatment conditions through the response surface methodology. A total of nine experimental points were studied according to the central composite design. The temperature and time were set as independent variables, and the redness, ΔE value, aerobic bacteria, coliform group, polyphenol oxidase (PPO) activity, total polyphenol content (TPC), and total flavonoid content (TFC) related to the quality characteristics were set as dependent variables. The redness and the ΔE value were measured as −0.38∼1.20 and 0.97∼11.88, respectively, and the R² value was 0.9754 and 0.9818, respectively. The R2 value of viable cell counts were 0.9849 and 0.9714 in the aerobic bacteria and coliform groups. The PPO activity was 122.57∼235.13 g/min, and the R² value was 0.8616. The TPC and TFC as active ingredients of pear puree were in the range of 19.33∼24.54 and 4.56∼5.78 GAE mg/100 g, respectively, and the R² values were 0.9181 and 0.9097, respectively. Based on this, the contour map was superimposed to set the optimal hydrothermal treatment conditions. The optimum points derived were 74.6°C and 20.7 min. When the predicted and the experimental values were compared to verify the reliability of the model, all the experimental values of each of the response variables were within the 95% confidence and prediction intervals, confirming the suitability of the model.

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>

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>

경부고속철도 회생 에너지 저장시스템 성능 분석

장민주(Min-Ju Jang),전용주(Yong-Joo Jeon),노영환(Young Hwan Lho) 대한전기학회 2015 전기학회논문지 Vol.64 No.9

Recently, various researches are conducted in the application of regenerative energy produced during the operation of an electric locomotive. Regenerative energy is produced by a generator in the brake procedure. The generator is operated by kinetic energy of an electric railroad using an electric motor. The process of producing regenerative energy varies with the current type of a railroad and its running condition. The quality of electric power can be improved and electric energy can be utilized effectively, especially in the use of an energy storage system (ESS). Thus, it is necessary to apply ESS into AC section and high speed railway. This study analyses the composition of the regenerative ESS equipment installed in Yong-Jeong sectioning post, operational principle, charge and discharge algorithm and energy efficiency. The analysis shows that CO2 emissions can be reduced about 0.5 ton per a day. In addition, ESS helps saving the energy and the compensation of the voltage drop caused by the operation of high speed train when it is installed at the end of the feeder section. The number of high speed train will be increased continuously related to the electrification rate. Therefore, applying the ESS to high speed railway is expected to solve the instability of the feeder voltage and the equipment capacity problem caused by the high speed trains.

직접 검화법을 이용한 조제분유의 콜레스테롤 분석법 개발

김진만,박정민,윤태형,임동길,윤창용,정자영,정인식,곽병만,안장혁,Kim, Jin-Man,Park, Jung-Min,Yoon, Tae-Hyung,Leem, Dong-Gil,Yoon, Chang-Yong,Jeong, Ja-Young,Jeong, In-Seek,Kwak, Byung-Man,Ahn, Jang-Hyuk 한국축산식품학회 2011 한국축산식품학회지 Vol.31 No.6

본 연구에서는 조제분유 중의 콜레스테롤을 신속하고 정확하게 분석하기 위해 지방 추출 과정을 거치지 않는 직접 검화 방법을 선택하여 분석법 개발을 시도하였다. 조제분유 분말시료를 직접 검화 수기에 취하여 검화 온도, 검화 시간, KOH 농도의 3가지 인자에 대해 콜레스테롤 회수율이 가장 양호하게 나타나는 최적 검화조건을 확립하고, 검화 후 수세과정에서 액액 분배가 용이한 용매 조건도 확립하였다. 또한 콜레스테롤 피크의 완전한 분리를 위한 적정 기기 조건을 확립하였다. 그 결과, 시료 약 2 g에 16 M-KOH 10 mL를 넣고 $90^{\circ}C$에서 60분 가열하여 검화한 후 diethyl ether로 3회 추출하고 hexane을 최종시험용액으로 하여 기기분석을 했을 때의 회수율이 98.80%로서 가장 양호하게 나타났다. 본 연구를 통해 개발된 조제분유의 효율적인 액액분배 및 직접가열 검화법은 일원배치 분산법에 의해 유화가공식품의 콜레스테롤 분석법으로 유효성이 검증되었으며, 아울러 개발된 전처리 방법 및 기기 분석 조건을 활용해 다양한 분석 기관에서 신속 정확하고 효율적인 콜레스테롤 분석을 수행할 수 있을 것으로 기대된다. 또한 산업체의 품질관리 및 검증기관에서 필요시 모니터링에 적극 활용 가능할 것으로 사료되며, 이를 통해 유화가공식품 류의 함량표시 및 규격관리의 정확성과 효율성 증대에 기여하여 제조업체의 정확하고도 효과적인 품질 및 안전성 확보에 기여할 수 있을 것으로 판단된다. 특히 위해 물질에 대한 정확한 함량 판단이 중요한 조제분유 등의 영 유아용 식품의 안전성 확보에 지대한 공헌을 할 수 있을 것으로 기대된다. An improved cholesterol analysis method was developed for powdered infant formula by gas chromatographic separation after liquid-liquid extraction and partition. In the official Korea Food Standard method for cholesterol analysis, the water phase and solvent phase were not well separated in the case of emulsified foods such as powdered infant formulas and baby foods. For the rapid and simple sample preparation method, an optimized direct saponification condition was established for heating temperature, heating time, and KOH concentration. From the results, the optimum conditions were as follows: heating temperature $90^{\circ}C$, heating time 60 min, and 16 M KOH 10 mL for a 2 g infant formula sample; improved separation condition for gas chromatography was as follows: the initial oven condition was $250^{\circ}C$ for 25 min, the oven temperature was increased to $290^{\circ}C$ by $10^{\circ}C$/min ratio, and finally the oven temperature remained at $290^{\circ}C$for 9 min. The developed method could be implemented for the study of cholesterol, providing the advantages of reduced inspection time and cost in emulsified foods such as infant formula.

재구성 가능형 공작기계의 주축 시스템 설계

장성현,정용민,황현영,최영휴,박종권 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

During a decade, there are many researches on microfactory which is the miniature, flexible, and efficient manufacturing system for the micro/meso scale machining device. Moreover many micro machine tool has developed in Japan, U.S., Europe, and Korea. Already we developed a 3-axis micro milling machine with 300×200×320 ㎣ machine size for microfactory. In this study, we introduce the design of a high speed spindle system with air bearings for our micro milling machine. Desired operation speed range of the spindle system is 100,000 ~ 150,000 rpm. In. design step, we have consideration for minimum critical speed, compliance, and weight construction of the spindle system. The shaft length, the shaft outer diameter, bearing positions and bearing stiffness were set as the design values. After the final design of spindle model, we carried out dynamic analysis a spindle system for a micro milling machine by using ADROS, which is our own developed S/W for dynamic design analysis of rotor systems. As the result, we designed a spindle system having the critical speed above the operating speed.

평면 2자유도 모델을 이용한 리니어 모터로 구동되는 다축 마이크로 밀링머신 크로스헤드의 진동해석

장성현,황현영,정용민,최영휴,홍정표 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

In this paper, a simple 2-D.O.F. planar motion model is proposed in order to analyze the snake motion of a cross head assembly of a Multi-axis micro milling machine (M4) for BT-factory, that is travelling on linear guide. In the proposed mathematical model, the friction between head and guide ways is neglected, and also the support structures including the linear guides of M4 are assumed to be rigid. The equations of motion of the proposed model are derived and successfully solved to determine vibration responses of a cross head assembly due to some applied traction forces.

다발성 연조직 종괴를 동반한 급성 림프구성 백혈병의 증례 보고

장정용,허경회,이원진,허민석,이삼선,최순철 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.2

A 15-year-old patient, who had been diagnosed and treated as Burkitt cell type acute lymphoblastic leukemia (ALLL3) already, visited our department. He complained of gingival enlargement and loosening teeth 1 month ago. The clinical examination revealed anterior open bite, gingival enlargement, and nontender swelling particularly in molar regions of both jaws. Deep periodontal pockets and severe mobility was shown on most of the teeth. The panoramic radiographs showed severe bone destruction and extrusion of the molars. The contrast enhanced CT showed multiple enhanced mass and bone marrow obliteration in both jaws. Chemotherapy was done and the swelling was subsided at 1 month later. In conclusion, radiologic findings of leukemia with soft tissue mass, known as chloroma or granulocytic sarcoma, mimic those of lymphoma, so blood test may be needed for the final diagnosis.