Effects of Industrial By-products on Reducing Heavy Metal Leaching in Contaminated Paddy Soil

Oh, Se Jin,Oh, Seung Min,Kim, Sung Chul,Ok, Yong Sik,Ko, Tae Yol,Ji, Won Hyun,Yang, Jae E. 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.1

Soil contamination with arsenic and heavy metals is a worldwide problem. Main objective of this research was to evaluated effects of reducing heavy metal leaching under reduced soil condition amended with industrial by-products. The contaminated soil was amended with 3% (w/w) of limestone (Ls), steel slag (SS) and acid mine drainage sludge (AMDS). Synthetic acid rain ($H_2SO_4:HNO_3=6:4$, pH 5.5 fixed) was used for feeding solution with flow rate of $0.78{\sim}0.88mL\;min^{-1}$. Results showed that similar pH and EC of leachate was observed in all treatments regardless of applied industrial by-products. However, arsenic concentration of leachate increased when industrial by-products were mixed. Meanwhile, concentration of heavy metal in the leachate decreased from 11.3 to 4.59 mg for Cd, from 92.3 to 7.93 mg for Pb, and from 11,716 to 1,788 mg for Zn via immobilization in soil with AMDS amended, respectively. Overall, application of industrial by-products can be an environmentally-friendly way to remediate soil and(or) leachate contaminated with metal(loid)s in metal mine site.

Bending Performance of Flexible Organic Thin-Film Transistors With/Without Encapsulation Layer

Oh, Jongsu,Kim, Jin-Ho,Lee, So Young,Kim, Min Su,Kim, Jae Moon,Park, Keechan,Kim, Yong-Sang IEEE 2018 IEEE transactions on device and materials reliabil Vol.18 No.1

<P>Flexible pentacene-based organic thin-film transistors (TFTs) were fabricated and their performance was investigated as a function of the bending radius and the thickness of the polydimethylsiloxane (PDMS) encapsulation layer. The TFTs were fabricated on a flexible polyimide film (film thickness: 75 <TEX>$\mu \text{m}$</TEX>), and encapsulated by a PDMS layer. Degradation of the device performance during application of a tensile bending stress of 3 mm was minimized by utilizing an encapsulation layer thickness of 75 <TEX>$\mu \text{m}$</TEX>, because the mechanical strain on the pentacene layer was almost off-set (tensile strain was applied to the bottom layer of the pentacene, and compressive strain was applied to the top layer of pentacene). At the tensile bending stress of 3 mm, the performance of the non-encapsulated TFT was degraded, whereas the encapsulated device showed great stability. This flexibility and bending stability were enabled by the use of the 75- <TEX>$\mu \text{m}$</TEX> PDMS encapsulation layer, due to the location of the pentacene active layer in the neutral region position. A mechanical reliability test was performed for 120 min with a bending radius of 3 mm, demonstrating that only the device with the 75- <TEX>$\mu \text{m}$</TEX> thick encapsulation layer showed stable device performance over a stress time of 120 min.</P>

Simultaneous Gas Chromatography-Mass Spectrometric Determination of Total and Individual Phthalic Esters Utilizing Alkaline Hydrolysis and Silyl Derivatization Technique

Kim, Min-Seon,Li, Dong-Hao,Shim, Won-Joon,Oh, Jae-Ryoung,Park, Jong-Man Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.3

Environmentally important phthalic esters have been analyzed by GC-MS in terms of individual phthalic esters or total phthalic esters directly or after derivatization. Derivatization improves the chromatographic characteristics of the highly polar phthalic esters. This study focused on the GC-MS determination of the total phthalic esters and the individual phthalic esters simultaneously. The phthalic esters were hydrolyzed to phthalate and corresponding alcohols in 1 M NaOH solution at 90 oC for 30 min followed by extraction with ethyl acetate after acidifcation. The phthalic acid and alcohols were simultaneously silyl derivatized using bis(trimethylsilyl)trifluoroacetamide (BSTFA) to their corresponding silyl ester and ethers in the mixture of 60% acetone and 40% ethyl acetate at room temperature within 30 min. Because of the high reactivity of BSTFA with the phthalic acid and alcohols effective silyl derivatization was possible simultaneously. GC-MS analysis of the silyl derivatives of phthalic acid and alcohols was performed. The total phthalic ester content was estimated from the analytical result of phthalic silyl ester, while the individual phthalic ester was quantified from the analytical results of alcoholic silyl ethers. This technique was applied to spiked tab water and real seawater samples from the Lake Shihwa in Korea. The results were checked against the results from the direct GC-MS analysis of the phthalic esters and reasonable recoveries with high sensitivity were achieved. The recoveries were higher than 75% with low relative standard deviation (below 10%).

국내외 수용가 맞춤형 수력발전시스템 현대화개발 및 실증

오민환(Min-Hwan Oh),신기석(Ki-Seok Shin),임재황(Jae-Hwang Lim),윤여창(Yeo-Chang Yun),김현아(Hyun-Ah Kim),강석원(Seok-Won Kang),백종명(Jong-Myung Paik),이준용(Jun-Yong Lee) 대한전기학회 2017 대한전기학회 학술대회 논문집 Vol.2017 No.10

EAF Slag의 해양복토제 활용을 위한 PO₄<SUP>­</SUP>-P 제거특성에 관한 연구

김재원(Jae-Won Kim),서종범(Jong-Beom Seo),강민경(Min-Gyeong Kang),김인득(In-Deuk Kim),오광중(Kwang-Joong Oh) 한국청정기술학회 2010 청정기술 Vol.16 No.4

본 연구에서는 제강전기로 슬래그를 해양복토제로 활용하기 위한 인제거 특성실험을 실시하였다. 제강전기로 슬래그의 PO₄<SUP>-</SUP>-P 제거 특성에 관한 시험 결과, 슬래그 내의 CaO는 Ca<SUP>2+</SUP>와 OH<SUP>-</SUP>로 이온화됨에 따라 PO₄<SUP>-</SUP>-P와 반응하여 HAP를 형성함으로써 용액 중에 존재하는 PO₄<SUP>-</SUP>-P를 효과적으로 제거하는 것으로 나타났다. 연속반응기를 통한 해수 내 PO₄<SUP>-</SUP>-P의 지속적인 유입에 대한 제거특성을 확인한 결과, 칼럼 내 PO₄<SUP>-</SUP>-P 농도는 반응 3일 이후 급격히 감소하여 10일 이후에는 0.5 ppm 이하로 나타났다. 실제 연안해역의 저질을 이용한 제강전기로 해양복토제 적용실험 결과, 반응 25일 후 PO₄<SUP>-</SUP>-P 발생량을 93∼ 98% 저감시키는 것으로 나타났다. 이러한 결과를 바탕으로 제강전기로 슬래그를 해양복토제로 활용할 경우 PO₄<SUP>-</SUP>-P 제거 및 억제효과가 있으며, 파쇄선별 등 별도의 추가공정 없이 적은 량으로도 사용 가능할 것으로 판단된다. This study estimated the possibility of phosphate removal characteristics to utilize EAF(electric arc furnace) slag as submarine cover material. The major phosphate removal mechanism was a certain formation of HAP precipitation occurred by the ionization reaction between Ca<SUP>2+</SUP> and OH<SUP>-</SUP>, which were leached from the EAF Slag. Another phosphate removal mechanism was the adsortion of EAF slag surface. As a result of PO₄<SUP>-</SUP>-P removal characteristics using continuous column reactor, PO₄<SUP>-</SUP>-P concentration decreased rapidly after 3 days and 10 days later, it show under 0.5 ppm. The result as applied in real sea water, shows that the phosphate removal effects were 93∼98% by the subaqueous sediment removal using the EAF slag. In conclusion, EAF slag is useful in PO₄<SUP>-</SUP>-P removal and control and it is possible to use without additional process like crush and selection.

Effects of Industrial By-products on Reducing Heavy Metal Leaching in Contaminated Paddy Soil

Se Jin Oh,Seung Min Oh,Sung Chul Kim,Yong Sik Ok,Tae Yol Ko,Won Hyun Ji,Jae E. Yang 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.1

Soil contamination with arsenic and heavy metals is a worldwide problem. Main objective of this research was to evaluated effects of reducing heavy metal leaching under reduced soil condition amended with industrial by-products. The contaminated soil was amended with 3% (w/w) of limestone (Ls), steel slag (SS) and acid mine drainage sludge (AMDS). Synthetic acid rain (H₂SO₄:HNO₃ = 6:4, pH 5.5 fixed) was used for feeding solution with flow rate of 0.78~0.88 mL min-1. Results showed that similar pH and EC of leachate was observed in all treatments regardless of applied industrial by-products. However, arsenic concentration of leachate increased when industrial by-products were mixed. Meanwhile, concentration of heavy metal in the leachate decreased from 11.3 to 4.59 mg for Cd, from 92.3 to 7.93 mg for Pb, and from 11,716 to 1,788 mg for Zn via immobilization in soil with AMDS amended, respectively. Overall, application of industrial by-products can be an environmentally-friendly way to remediate soil and(or) leachate contaminated with metal(loid)s in metal mine site.

Electrophoretic Preparation of an Organic–Inorganic Hybrid of Layered Metal Hydroxide and Hydrogel for a Potential Drug‐Delivery System

Gwak, Gyeong‐,Hyeon,Paek, Seung‐,Min,Oh, Jae‐,Min Wiley-VCH 2012 European journal of inorganic chemistry Vol. No.

<P><B>Abstract</B></P><P>We have prepared organic–inorganic hybrid materials consisting of layered metal hydroxides and hydrogel polymers for potential use as a drug delivery system. The hybrid materials were synthesized by an electrophoretic method; anionic precursors, OH<SUP>–</SUP>/CO<SUB>3</SUB><SUP>2–</SUP>, and cationic metal Zn<SUP>2+</SUP> were migrated into hydrogel by applying an electrical potential of 25 V for 20 min to form inorganic nanocrystals inside the hydrogel matrix. Hydrozincite [Zn<SUB>5</SUB>(OH)<SUB>8</SUB>(CO<SUB>3</SUB>)] nanoparticles, a kind of layered metal hydroxide, were determined to develop inside the hydrogel according to powder X‐ray diffraction, FTIR, and X‐ray absorption spectroscopy. Scanning electron microscopic images showed that the prepared hybrid materials have well‐dispersed inorganic nanoparticles in the hydrogel matrix. In order to evaluate the potential of the thus prepared hybrid materials as a drug‐delivery system, the well‐known antioxidant ferulic acid was incorporated and their time‐dependent release profile was obtained by HPLC.</P>

Controlled Crystal Growth of Two-Dimensional Layered Nanomaterials in Hydrogel via a Modified Electrical Double Migration Method

Gwak, Gyeong-Hyeon,Kwon, Na Kyung,Lee, Won-Jae,Paek, Seung-Min,Kim, So Youn,Oh, Jae-Min The American Chemical Society 2017 CRYSTAL GROWTH AND DESIGN Vol.17 No.12

<P>Layered double hydroxide (LDH) nanomaterials of uniform size and homogeneous distribution are successfully developed in agarose hydrogel through the electrical double migration method. To grow LDH crystals in agarose matrix, both cationic (Ni<SUP>2+</SUP>, Ga<SUP>3+</SUP>) and anionic precursors (OH<SUP>–</SUP> and CO<SUB>3</SUB><SUP>2–</SUP>) of LDH are simultaneously transported from solution to agarose hydrogel through electric potential, resulting in the in situ crystal growth of LDH. X-ray diffraction patterns, X-ray absorption spectra, and high-resolution transmission electron microscopic images confirm that the developed LDH is ∼15 nm in size and had a well-defined crystal structure. Scanning electron microscopy and small-angle X-ray scattering spectroscopy showed homogeneous arrays of LDH nanocrystals along agarose sheets with homogeneous distribution. On the basis of the characterization results, we suggest that crystal nuclei are first developed on the agarose chain, and then LDHs homogeneously grow along sheets of agarose matrix.</P><P>Layered double hydroxides (LDHs) of uniform size and homogeneous distribution are developed in agarose hydrogel through the electrical double migration method. Developed LDH had a well-defined crystal structure and homogeneous arrays along agarose sheets with homogeneous distribution. Thus, we suggest that crystal nuclei are first developed on the agarose chain, and then LDHs homogeneously grow along sheets of agarose matrix.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cgdefu/2017/cgdefu.2017.17.issue-12/acs.cgd.7b01252/production/images/medium/cg-2017-01252b_0009.gif'></P>

개의 췌도분리에서 췌장의 팽창과 콜라겐 분해요소

이상훈,김성주,박정환,김종성,오승훈,한진수,정인경,양태영,김동준,김광원,이문규,민용기,이명식,정재훈,함종렬 대한당뇨병학회 2000 Diabetes and Metabolism Journal Vol.24 No.2

Backgrounds: One of the main problems conditioning the outcome of islet transplantation is the ability to separate a sufficient number of viable islets with preserved function. Islet purification is critically affected by all of the isolation stages. Thus, it is necessary to set up the standard isolation method that islets are separate well from acinar without compromising islet yield and viability. Methods: Twenty three adult mongrel dogs were used for the experiment of total pancreatectomy with islet isolation. The islets were properly isolated by a modified Recordi method. The obtained islets were further purified by centrifugation on discontinuous gradients using cell separation system (Model 2991, Cobe, Lakewood Colo). We evaluated islet number (islet equivalent number, 150 um equivalents/kg of recipient body weight, IEq/kg), purity, cell volume, viabilty, recovery rate, and comparison of outcome according to the isolation conditions. Results: 1) The mean of islet numbers before purification were 13543±9431Eq/kg, digestion times were 13.8±2.6 min., digestion temperature was 37.4±0.2℃, purity was 59.7?.0%, viability was 90.0±2.1%, cell volume was 4.7±1.1 mL, islet number after purification were 4064±361 IEq/kg, and recovery rate was 29±2.9%. 2) Isolated islet numbers were different according to the degree of pancreas distension with collagenase, digestion temperature, and digestion time. 3) The best conditions for islet isolation were above 37.5℃ in temperature at recirculation of collagenase, within 12 min in digestion time and well distended pancreas with collagenase. 4) According to multiple regression adjusted by variable factors, the degree of pancreas distension with collagenase and digestion time were independently associated factors for successful islet isolation. Conclusions: In this study, we concluded that the degree of pancreas distension with collagenase and digestion time were independent factors for successful islet isolation and the best conditions for islet isolation were above 37.5℃ in temperature at recirculation of collagenase, within 12 min in digestion time and well distended pancreas with collagenase.

전압품질 보상장치의 순간전압강하 검출 알고리즘

오중민, 이재영 김천대학교 2004 김천대학교 논문집 Vol.25 No.-

The recent growth in the use of impactive and nonlinear loads, elec-tronic, and medical devices sensitive to power quality has caused many power quality problems and power supply-and-demand problem. Recently, in power system, not only the reliability of the power supply but also the DVR(Dynamic Voltage Restorer), UPS, and APF are being studied more and more. Hence, in this paper, Voltage sag detection algo-rithm for voltage sag corrector is proposed. Also, simple circuit for the experimental voltage sag is introduced.