• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.307-316
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• 2016

Objectives: In general, NIOSH method 5506 is most widely used for the occupational exposure measurement of PAHs, but 2-4 ring PAHs have poor desorption efficiency, especially for a filter. The purpose of this study was to determine a method to increase the desorption efficiency of 16-PAHs using an ultrasonic extraction procedure. Methods: Test samples prepared spiked XAD-2 tubes and PTFE filters in the range of $0.01-1.0{\mu}g/mL$ for desorption efficiency study. Four different extraction solvents, acetonitrile, acetone, tetrahydrofuran and dichloromethane, were tested in order to select the most suitable solvent for the extraction of the 16 PAHs. The addition of dimethyl sulfoxide and sonication time were considered in order to determine the method with the highest extraction efficiency. All samples were made in three sets and analysis was replicated seven times by HPLC. Results: Acetonitrile and acetone were the optimized as an extraction solvent and desorption efficiency of 2-ring PAHs such as naphthalene, acenaphthylene were increased 3~19% with dimethyl sulfoxide for XAD-2. Acetone was the best extraction solvent for PTFE filter and the desorption efficiency was increased 3~13% for 2- to 4-ring PAHs. The optimum sonication time was 60 minutes and desorption efficiency increased with extraction time. Conclusions: As a result, the best extraction solvent was acetone with dimethyl sulfoxide for ultrasonic extraction procedure and the desorption efficiency of this method was better than NIOSH 5506's. This study could be applied as a method for occupational exposure measurement of PAHs.

• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.2
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• pp.73-79
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• 2014

Covalent attachment of 1, 4-dimethylnaphthalene (DMN) based endoperoxide forming subunits to a polyvinyl butyral (PVB) backbone has been achieved. The functionalized polymer materials prepared and characterized here can serve as biocompatible carrier systems for studying cellular uptake, intermediate storage and delayed release of singlet oxygen, which opens up new doors for optimizing a variety of medical applications of photogenerated DMN-endoperoxides such as antiviral, antibacterial, antiplasmodial and antitumor activity.

• YAKHAK HOEJI
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• v.19 no.2
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• pp.101-110
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• 1975

p-Chloronitrobenzene(substrate) and p-nitrophenetole (product) were quantitatively analyzed to know the degree of extent of reaction in the process of time. The calibration curve was prepared by the internal satndard method in gaschromatography. 2,6-Dimethyl-naphthalene was used as internal standard. The rate constant(k), the reaction velocity in various concentrations of NaOH altered, and the formation of byproducts(azo-compound and p-nitrophenol) with the amounts of MnO$_{2}$ and NaOH altered, were studied. From the results of these of MnO$_{2}$ and NaOH altered, were studied. From the results of these experiments, this reaction was second order and the rate constant was k=10.3 $\times$ 10$^{-3}$ mole$^{-21$. When p-chloronitrobenaene 1 pt. NaOH 0.56pts. MnO$_{2}$ 0.5pts. and ethanol 25 pts-were reacted about 10 hours, p-nitrophenetole was nearly quantitatively obtained without byproducts.

• Membrane Journal
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• v.25 no.3
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• pp.231-238
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• 2015

Co-polyimide membranes were prepared by two-step polymerization using semi-alicyclic 5-(2,5-dioxotetrahydrofuryl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride (DOCDA) with five diamines such as 2,5-dimethyl-1,4-phenylene diamine (2M), 2,4,6-trimethyl-1,3-phenylene diamine (3M), 1,5-naphthalene diamine (NDA), 4,4-diaminodiphenyl methane (MDA), 4,4'-diaminodiphenyl ether (ODA). Synthesized co-polyimides were characterized by FT-IR, viscosity, solubility, DSC, TGA and gas permeation properties, compared with 6FDA-based co-polyimides. All co-polyimides had the intrinsic viscosity of 0.32~0.58 and excellent solubility in various solvents. DOCDA-based co-polyimides had thermal stability over $400^{\circ}C$ although those were lower than 6FDA-based co-polyimides. Gas permeabilities of the copolyimide membranes were measured for $CO_2$ and $CH_4$ at room temperature and presented the trade-off relationship.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.244-244
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• 2012

유기발광소자는 빠른 응답속도, 높은 색재현성, 높은 명암비의 장점을 가지고 있어 차세대 디스플레이로 각광 받고 있으며, 이미 소형 디스플레이로 상용화되고 있다. 고효율과 색안정성을 가진 유기발광소자를 개발하기 위해 소자의 구조에 관한 연구가 활발히 이루어지고 있다. 하지만 청색 유기발광소자는 적색과 녹색 유기발광소자에 비해 낮은 신뢰성, 발광효율 및 색 순도의 문제점을 가지고 있어, 이를 개선하기 위한 다양한 연구가 필요하다. 청색 유기발광소자의 경우 발광층 내부로 주입되는 정공과 전자의 균형을 조절하기 위해 p-i-n 구조를 사용하거나 이리듐-유기물 합성물과 같은 인광물질의 적용하여 발광효율을 높이는 청색 유기발광소자에 대한 연구가 진행되고 있다. 그러나 정공 보조층과 청색 형광층의 도핑구조의 청색 유기발광소자에 대한 발광효율 증진 효과에 관한 연구는 고효율 유기발광소자의 성능향상을 위하여 필요하다. 본 논문에서는 진공 열 박막 증착 방법을 이용하여 정공 보조층과 청색 형광층으로 구성된 적층 발광구조를 사용한 청색 유기발광소자의 발광효율 증진 효과를 관찰하였다. 10%의 2,9-dimethyl-4,7-diphenyl-1,10-phenanthorlene (BCP)로 도핑된 2-methyl-9,10-bis (naphthalene-2-yl) anthracene (MADN)층을 발광층으로 사용한 유기발광소자, 5% MADN으로 도핑된 1, 3-bis (carbazol-9-yl) benzene (mCP) 층을 발광층으로 사용한 소자 및 10% BCP로 도핑 된 MADN 층과 5% MADN로 도핑된 mCP층을 혼합하여 발광층으로 사용한 유기발광 소자를 제작하였다. 유기 발광 소자의 전기적 광학적 특성을 비교하여 청색 유기발광소자의 발광효율 증가 효과를 규명하였다. 적층 발광층을 가지는 소자는 두 단일 발광층 중심부의 경계면에서 축적된 정공에 의해 발생한 공간 전하에 의한 내부 전위차이의 형성으로 발생된 인력으로 더 많은 전자들을 끌어 들이게 되어 발광효율을 증대시킨다. 이 실험의 결과는 MADN 형광물질을 가진 청색 유기발광소자의 발광효율을 증진 시키는 소자 구조를 제안하고 증진 효과에 대한 이해를 높이는데 도움을 줄 수 있다.

• Applied Chemistry for Engineering
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• v.18 no.2
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• pp.168-172
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• 2007

The separation of indole from a model mixture comprising four kinds of nitrogen heterocyclic compounds [indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)], three kinds of bicyclic aromatic compounds [1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN)], biphenyl (Bp) and phenyl ether (Pe) was examined by batch cocurrent 4 stages equilibrium extraction. The model mixture used as a raw material in this work was prepared according to the components and compositions contained in coal tar fraction (the temperature ranges of fraction: $240{\sim}265^{\circ}C$). An aqueous solution of formamide was used as a solvent. Indole was recovered more than 99% through 4 stages of the equilibrium extraction. The range of selectivity of indole in reference to DMN obtained through the 5 stages equilibrium extraction was found to be 63~118. The process for separation and recovery of indole contained in coal tar was studied by using the experimental results obtained from this work and the previous work.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.479-479
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• 2012

유기발광소자는 낮은 구동전압, 저전력, 높은 명암비, 빠른 응답속도, 넓은 시야각 및 높은 박막의 특성을 가지고 있어서 차세대 평판 패널디스플레이 기술로 각광받고 있다. 하지만 청색 유기발광소자는 적색과 녹색 유기발광소자에 비해 낮은 신뢰성, 발광효율 및 색 순도의 문제점을 가지고 있어, 이를 개선하기 위한 연구가 다양하게 연구되고 있다. 청색 유기발광소자의 경우 발광층 내부로 주입되는 정공과 전자의 균형을 조절하기 위해 p-i-n 구조를 사용하거나 이리듐-유기물 합성물과 같은 인광물질의 적용하여 발광효율을 높이는 청색 유기발광소자에 대한 연구가 진행되고 있다. 하지만 정공 보조층과 청색 형광층의 도핑구조의 청색 유기발광소자에 대한 발광효율 증가 메커니즘에 관한 연구는 비교적 많이 이루어지지 않았다. 본 연구에서는 열 증착 방법을 이용하여 정공 보조층과 청색 형광층으로 구성된 이중 발광층을 사용한 청색유기발광소자의 발광효율 증가 메커니즘에 대해 연구하였다. 10%의 2,9-dimethyl-4,7-diphenyl-1,10-phenanthorlene (BCP)로 도핑된 2-methyl-9,10-bis(naphthalene-2-yl)anthracene (MADN)층을 발광층으로 사용한 유기발광소자, 5% MADN으로 도핑된 1, 3-bis(carbazol-9-yl)benzene (mCP) 층을 발광층으로 사용한 소자 및 10% BCP로 도핑 된 MADN 층과 5% MADN로 도핑 된 mCP층을 혼합하여 발광층으로 사용한 소자의 전류밀도-전압-발광 특성을 비교하여 청색 유기발광소자의 발광효율 증가 메커니즘을 분석하였다. 이중 발광층을 가지는 소자는 두 단일 발광층 중심부의 경계면에서 축적된 정공에 의해 발생한 쿨롱 인력으로 더 많은 전자들을 끌어들이게 되어 엑시톤 형성 및 빛 방출이 증가하였다. 이 실험의 결과는 MADN 형광물질을 가진 청색 유기발광소자의 발광효율 증가 메커니즘에 대한 이해를 높이는데 도움을 줄 수 있다.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.74-83
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• 1983

In order to examine the relationship of fruit abscission and ethylene evolution in 'Jojuro' and 'Imamuraaki' pear trees, the thinning chemicals, ${\beta}$-naphthalene acetic acid (NAA), O, O-dimethyl-O-(3-methyl-4 nitrophenyl) posphorothioate (MEP), 1-naphthyl N-methyl carbamate (carbaryl), and 2-chloroethyl phosphonic acid (ethephon) were applied. Concurrently the effect of calcium acetate on the control of fruit abscission were examined when calcium acetate was added to ethephon and carbaryl. 1. All the applied chemicals (MEP, NAA, carbaryl and ethephon) was effective to abscise fruits in 'Jojuro', and MEP and carbaryl in 'Imamuraaki's. 2. The application of ethephon increased the ethylene evolution but other chemicals did not increase it. 3. There were no significant differences in total sugar contents of fruits by MEP, NAA, carbaryl and ethephon treatments. 4. When the calcium acetate was added to the ethephon and carbaryl, the thinning effects were offsetted. 5. The rate of defoliation due to ethephon treatment was controlled by addition of calcium acetate at 0.1~0.25 M. It was clarified that fruit abscission induced by thinning chemicals except ethephon was not directly related to ethylene production and that degree of fruit thinning can be regulated by addition of calcium acetate to thinning chemicals.