• Elastomers and Composites
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• 제43권2호
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• pp.72-81
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• 2008

포장도로의 소성변형을 줄여보고자 개질아스팔트가 나타나고 있다. 본 연구에서는 타이어 고무 등을 이용하여 개질된 아스팔트의 물성을 알아 보았다. 마샬안정도와 인장강도가 각각 98% 및 43% 증가하여 타이어 고무의 개질효과를 알 수 있었다. 점도, 침입 및 열 분석에서 아스팔트의 변형저항성이 향상되었음을 알 수 있었다. IR 및 GPC 실험에서 개질제의 구조가 아스팔트의 구조와 유사할 경우 두 화합물 사이에 화학결합이 발생하여 분자들의 크기가 증가함으로써 개질효과가 커짐을 알 수 있었다.

• Korean Chemical Engineering Research
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• 제53권6호
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• pp.792-797
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• 2015

그래핀은 다양하고 뛰어난 물성으로 그 적용 분야가 넓다. 그러나 반델반스 상호 작용으로 유기용매 내에서 쉽게 분산되지 않고 뭉쳐 있거나 포개진 상태로 존재한다. 게다가 그래핀은 화학적으로 비활성이며 크기나 모양이 넓은 분포도를 가지므로 균일한 상태 유지가 어렵다. 본 연구에서는 덩어리로 구성된 그래핀을 용매에 분산시키고 개질시키는 방법에 대해서 고찰하였다. 분산방법으로서 i) 유리비드를 이용한 물리적 분쇄. ii) 유리비드와 초음파를 이용한 처리 iii)유기용매에서의 분산 iv)드라이아이스를 이용한 개질법이 포함된다. 2.5 mm 크기의 유리비드처리는 대조구와 비교하여 36.4%의 감소율을 나타내었다. 유리비드(2.5 mm)와 초음파(225W, 10분) 병용 처리구가 76%로 입자 크기 감소효과를 나타내었다. 그래핀 입자 크기감소는 유리비드의 크기와 초음파 처리강도와 처리시간에 의존되었다. Ethyl acetate(EA)와 Isoprophyl alcohol(IPA)의 용매로 그래핀 표면을 개질시켰다. IPA용매에서 FT-IR 분석결과 CO 작용기가 높게 나타남으로 확인할 수 있었다. 한편, 드라이아이스로 그래핀 표면을 개질시킨 결과 처리 전 산소함량이 0.80%에서 처리 후 4.90%로 산소 함량 크게 증가되었다. 본 연구 결과로부터 IPA용매에 그래핀을 분산시킬 때 CO 작용기가 증가하여 장시간 분산상태 유지에 도움이 되는 것으로 판단된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.635-638
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• 2003

For the acute assessment on biological toxicity of wastewater, surface plasmon resonance(SPR) based cell viability detection was performed using gold surface-confined cell as a result of adhesion-modifying chemicals. Escherichia coli O157:H7 (E. coli O157:H7) was investigated after exposure to EDTA. Cells were immobilized on gold coated slide glass for SPR analysis by the method of cross-linking carboxyl group on the bacterial surface with amine group of poly-L-lysine that had been coupled to the gold surface modified by a self-assembled monolayer of 11-mercaptounde canoic acid (11-(MUA)). Reflective intensity of each flow step was changed with respect to confect of ethylenediaminetetraacetic acid (EDTA) disodium salt and phosphate-buffered saline (PBS) solution. The proposed detection technique can be used for biological toxicity test.

• 한국의상디자인학회지
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• 제3권1호
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• pp.15-31
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• 2001

Textile fabrication affected by consumer and selected by fashion designer. The textile fabrication has been made not only by introducing the newly developed fiber but also by modifying the existing textile materials to impart sensibility to them. Consumers choose but to their sensibility of textile material and fashion trend. On purpose in this research is find out have influence on textile image. Wool fabrics have been in use from early age in northern Europe. Recognition of the role of the morphological structure, surface properties, chemical composition, acid-base characteristics in the chemical treatment of wool led to quantum advances in the fields of setting, shrink-resisting, chemical modification, and internal fiber cross-linking. Mechanical finishing to develop the handle, drape, and surface characteristics of the fabric is at least as important as chemical or wet finishing. Result showed that to have variety sensibility and trend theme in wool fabrics are tweed, venetian, serge, gabardine and melton.

• Korean Chemical Engineering Research
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• 제45권1호
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• pp.103-108
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• 2007

HAZOP 기법은 전문가의 경험과 지식을 기초로 브레인스토밍(brainstorming) 방식을 적용함으로써 체계적으로 잠재 위험을 분석, 평가하는 방법으로 검토 시 누락의 가능성을 배제하고 비교적 객관화된 평가서를 작성할 수 있는 장점으로 인하여 널리 이용되고 있다. 그러나 대규모 화학공장에서는 HAZOP 기법을 이용한 위험성 평가의 실시 및 그 결과의 활용이 잘 이루어지고 있으나, 중 소 화학공장들의 경우 기법 적용이 용이하지 못하여 현실적으로 많은 어려움을 겪고 있다. 이에 본 연구에서는 기존에 많이 사용되고 있는 위험성 평가 기법들의 장 단점을 분석 검토하여 중 소 화학공장의 현장에 적용하기 쉬운 위험성 평가 기법을 제시함으로써 사업장 위험 관리 수준의 향상에 기여하고자 하였다.

• BMB Reports
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• 제33권2호
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• pp.172-178
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• 2000

The lipoxygenase was purified 35 fold to homogeneity from the Korean red potato by an ammonium sulfate precipitation and DEAE-cellulose column chromatography. The simple purification method is useful for the preparation of pure lipoxygenase. The molecular weight of the enzyme was estimated to be 38,000 by SDS-polyacrylamide gel electrophoreses and Sepharose 6B column chromatography. The purified enzyme with 2 M $(NH_4)_2SO_4$ in a potassium phosphate buffer, pH 7.0, was very stable for 5 months at $-20^{\circ}C$. Because the purified lipoxygenase is very stable, it could be useful for the screening of a lipoxygenase inhibitor. The optimal pH and temperature for lipoxygenase purified from the red potato were found to be pH 9.0. and $30^{\circ}C$, respectively. The Km and Vmax values for linoleic acid of the lipoxygenase purified from the red potato were $48\;{\mu}M$ and $0.03\;{\mu}M$ per minute per milligram of protein, respectively. The enzyme was insensitive to the metal chelating agents tested (2 mM KCN, 1 and 10mM EDTA, and 1 mM $NaN_3$), but was inhibited by several divalent cations, such as $Cu^{++}$, $Co^{++}$ and $Ni^{++}$. The essential amino acids that were involved in the catalytic mechanism of the 5-lipoxygenase from the Korean red potato were determined by chemical modification studies. The catalytic activity of lipoxygenase from the red potato was seriously reduced after treatment with a diethylpyrocarbonate (DEPC) modifying histidine residue and Woodward's reagent (WRK) modifying aspartic/glutamic acid. The inactivation reaction of DEPC (WRK) processed in the form of pseudo-first-order kinetics. The double-logarithmic plot of the observed pseudo-first-order rate constant against the modifier concentration yielded a reaction order 2, indicating that two histidine residues (carboxylic acids) were essential for the lipoxygenase activity from the red potato. The linoleic acid protected the enzyme against inactivation by DEPC(WRK), revealing that histidine and carboxylic amino acids residues were present at the substrate binding site of the enzyme molecules.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권3호
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• pp.258-261
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• 2006

The addition of zeolite particles enhances the stability of mRNA molecules in a cell-free protein synthesis system. When $20{\mu}g/{\mu}L$ of zeolite (Y5.4) is added to a reaction mixture of cell-free protein synthesis, a substantial increase in protein synthesis is observed. The stabilizing effect of zeolite is most dearly observed in an in vitro translation reaction directed by purified mRNA, as opposed to a coupled transcription and translation reaction. Upon the addition of zeolite in the in vitro translation reaction, the life span of the mRNA molecules is substantially extended, leading to an 80% increase in protein synthesis. The effect of zeolite upon the mRNA stability appears be strongly related to the cation exchange (potassium to sodium) reaction. Our results demonstrate the possibility of modifying this biological process using heterogeneous, non-biological substances in a cell-free protein synthesis system.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.197-198
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• 2000

A surface-assisted photo-control of the liquid crystal (LC) alignment has been achieved by modifying the topmost surface of the polyimide film with photo-reactive molecules. Recently, photo-alignment technique using a thin film of poly(vinyl cinnamates) have been reported. However their commercial potentiality is limited by their low thermal stability. To enhance thermal stability, we synthesized the chalcone derivatives as the photo-reactive molecules and introduced the materials on the surface-modified polyimide film.. We identified that the photo-chemical reaction of the chalcone derivatives occur in few minutes with irradiation of UV light. The photo-alignment characteristics of the modified polyimide films treated by polarized UV light and their LC cells are investigated as a function of exposure dose.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권4호
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• pp.257-262
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• 2003

A straightforward and effective method is presented for immobilizing enzymes on a microchip platform without chemically modifying a micro-channel or technically microfabricating a column reactor and fluid channel network. The proposed method consists of three steps: the reconstitution of a nitrocellulose (NC) membrane on a plane substrate without a channel network, enzyme immobilization on the NC membrane, and the assembly of another substrate with a fabricated channel network. As a result, enzymes can be stably and efficiently immobilized on a microchip. To evaluate the proposed method, two kinds of enzymatic reaction are applied: a sequential two-step reaction by one enzyme, alkaline phosphatase, and a coupled reaction by two enzymes, glucose oxidase and peroxidase, for a glucose assay.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.194-194
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• 2006

Polymer light-emitting diodes(PLEDs) have great potential application in large area flat panel displays and general lighting so intense academic and industrial research, and impressive scientific and technological progress has been achieved in this field. However, the efficiency and stability of PLEDs till need to be improved in order to fully realize the advantages of low cost and ease of fabrication provided by organic materials. Here, we report our effort to enhance the PLED' s performance in two approaches : 1) Utilizing nano-structured materials such as nano particles, clay, nano porous silica in active layer 2) Modifying the device structure in nano scale to improve not only the device efficiency but also its stability.