• 제목/요약/키워드: solvent effects

검색결과 1,325건 처리시간 0.024초

석유화학단지에서의 유기용제 노출에 의한 후천적 색각이상 (Acquired Color Vision Impairment among Solvent-Exposed Workers in Petrochemical industry)

  • 이은희;조성일;정해관;;백도영
    • 한국안광학회지
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    • 제9권2호
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    • pp.257-267
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    • 2004
  • 본 연구에서는 전라남도 여수지역의 한 석유화학단지애서 적어도 6개월이상 근무한 작업자 1030명을 대상으로 Lanthony D-15-desaturated 검사법을 이용하여 유기용제노출과 후천적 색각이상간의 연관성을 조사하였다. 작업환경측정은 전 작업시간(8시간) 단시료를 각 작업자에게 부착하는 개인시료를 활용하여 각 개인별 평균, 최대, 누적 연평균 8hr TWA를 산출하였다. 연구결과 연령이 높을수록 색혼란지수(CCI)가 유의하게 높았다(P<0.005). 형태에서는 청황색각이상의 분포가 노출군과 비노출군간에 통계적으로 유의한 수준은 아니었지만, 후천적 색각이상에서 주로 나타나는 제3색형과 제4색형 그리고 복합형이 대부분 노출군에서 높은 분포(비노출군 6.16%, 7.55%, 13.71%, 노출군 5.9%, 7.86%, 14.99%)를 보였다. 마지막으로 색각이상과 관련된 변수들을 보정하였을 때, 후천적 색각이상이 좌안에서는 비노출군과 비교하여 볼 때 통계적 연관성은 없었으나 노출군의 Odds ratio가 증가함을 보였다. 또한 연령에 대하여는 좌 우안에서 모두 높은 통계적 연관성을 보였다(p<0.01). 따라서 이 상의 결과로 근로자가 유기용제 중독으로 인해 초기 신경계이상의 증상으로 후천적 색각이상이 존재할 수 있으므로 안보건 사업에서의 또 하나의 일환으로 근로자의 안보건상태에 대한 지속적인 관심과 관리가 필요하다.

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PhosBholipase D에 의한 비천연 인지방질의 합성: IIl 포스타티딜기 전이반응에 미치는 유기용매의 효과 (Biosynthesis of Unnatural Phospholipids by Phospholipase D: II. Effect of Organic Solvents on Transphosphatidylation)

  • 정의호;이해익이상영
    • KSBB Journal
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    • 제6권3호
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    • pp.281-288
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    • 1991
  • This research was carried to investigate the effects of several organic solvents on the enzymatic transphosphatidylation in emulsion and two-phase solvent systems. The solvents having a similar dielectric constant with diethylether were effective for the enzyme activity. Diethylether and butylacetate were the most effective solvents, when added 12-15%(v/v) and 10-40%(v/v), respectively, for the synthesis of phosphatidylglycerol, phosphatidylethyleneglycol and phosphatidylpropyleneglycol. In the emulsion system, the size of ovolecithin liposome was increased and the clearness of the phospholipid bilayer was reduced as increasing the diethylether concentration. In the twophase solvent system, the rapidest reaction was obtained when water-organic solvent ratio was close to 1. The ratio of aqueous phase. however, should be lowered to 37% to gain the sole product of transphosphatidy1ation, without phosphatidohydrolysis.

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Effects of Hydrogen Peroxide Concentration on the Polymerization of p-Phenylphenol in Organic Solvent by Peroxidase

  • Yoo, Young-Je;Yeo, Joo-Sang;Park, Tae-In
    • Journal of Microbiology and Biotechnology
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    • 제5권3호
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    • pp.177-180
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    • 1995
  • In horseradish peroxidase-catalyzing polymerization of phenol under the water/dioxane solvent system, the optimal concentration of hydrogen peroxide was found to be 10 mmol/I. Feeding of hydrogen peroxide at its optimal concentration improved the polymerization performance by reducing reaction time and increasing molecular weights. Monomer conversions and the molecular weights of the enzymatically produced polymer were in the ranges of 83.1~94.2$%$ and 58000~68000, respectively.

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혼합용매중(混合溶媒中)에서의 식용(食用) Tar색소(色素)의 해리정수(解離定數)에 관(關)한 연구(硏究) (제 1 보)(第 1 報) -2',4',5',7'- Tetraiodofluorescein Sodium염(鹽)에 대(對)하여- (A Study on the Effects of the Dissociation Constant of Edible Tar Pigment. I)

  • 김박광;이민화;조영미;김길수;문동철
    • Journal of Pharmaceutical Investigation
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    • 제10권3호
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    • pp.14-19
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    • 1980
  • The dissociation constant of erythrosine in the mixed solvent systems of water-alcohols and water-acetone at various pH and in concentration media were determined by spectrophotometric method. Methanol, ethanol, and acetone were employed as solvents and studied the changes of pK values of erythrosine according to the kind and change of concentration of organic solvent which is mixed into water solution. The effect of organic solvent on pK is negligible at 40% while in the case of above 40% mixing, it is not negligible.

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PCP로 방부 처리된 탄약목상자의 자원순환형 처리기술 (Resource Recycling Technology for the PCP-treated Ammunition Box)

  • 이종철;최수
    • 한국군사과학기술학회지
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    • 제9권3호
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    • pp.123-131
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    • 2006
  • This paper reports the apparatus and method for the safe treatment of pentachlorophenol(PCP)-treated ammunition box by solvent extraction. Experimental variables were chosen as the composition of solvents, types of substance(chips and sawdust), temperatures and sonication to obtain maximum PCP removal from wood samples of the dismantled ammunition box. Up to 99% of PCP in the wood chip was extracted within 2 hours at room temperature when using methanol as the solvent. The extraction volume ratio of methanol per dried sample was about 10. Type of samples, extraction temperature and sonification showed little effects on PCP extraction. Based on this study, a resource recycling system for the treatment of ammunition boxes was recommended.

초음파 분무를 이용한 세라믹 테이프의 성형 (fabrication of Ceramic Tape By Ultrasonic Spray)

  • 윤정한;박양수;심수만;이해원
    • 한국세라믹학회지
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    • 제36권6호
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    • pp.625-631
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    • 1999
  • Ceramic tapes were fabricated by ultrasonically spraying slurries of monodispersed spherical and alumina powders. Effects of slurry compositions on tape forming were investigated. A relatively fast rate of solvent evaporation caused pores and cracks to be formed. A good chemical affinity between solvent and binder gave rise to binder separation resulting in inhomogeneous distribution of binder. Defect-free silica tapes with uniform distribution of particle packing and the binder were obtained from the solvent having a low chemical affinity and a slow evaporation rate and containing appropriate amounts of the binder and the plasticizer. Tape thickness could be controlled by adjusting solids loadings and slurry feed rates. It was possible to fabricate a tape in 15 $\mu\textrm{m}$ thickness from 7 vol% alumina slurry.

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Synthesis and Characterization of Alkyl Methacrylate-based Microgels by Experimental Design Method

  • Lee, Young-Keun;Jin, Fan-Long;Park, Soo-Jin
    • Bulletin of the Korean Chemical Society
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    • 제28권9호
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    • pp.1493-1498
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    • 2007
  • In this work, alkyl methacrylate-based microgels were synthesized by an experimental design method, and their sebum absorption characteristics were investigated. The results of fractional factorial experimentation indicated that the cross-linking agent content, solvent content, and stirring speed were the main parameters in the synthesis of the microgels. The suitable synthesis conditions were determined by the response surface design method. Through a study of the monomer and solvent effects, it was confirmed that the microgel shows the highest sebum absorption ratio when t-butyl methacrylate is used as a monomer or when acetone is used as a solvent. The optimal microgel synthesis conditions for cosmetic application were determined, and the resulting microgel had a mean particle size of 4.7 μm and a sebum absorption ratio of 435%.

Mechanistic Studies of the Solvolyses of Cyclohexanesulfonyl Chloride

  • Kang, Suk Jin;Koh, Han Joong
    • 대한화학회지
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    • 제63권4호
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    • pp.233-236
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    • 2019
  • In this study, the solvolysis of cyclohexanesulfonyl chloride (1) was studied by kinetics in ethanol-water, methanol-water, acetone-water, and 2,2,2-trifluoroethanol (TFE)-water binary solvent systems. The rate constants were applied to the extended Grunwald-Winstein equation, to obtain the values of m = 0.41 and l = 0.81. These values suggested $S_N2$ mechanism in which bond formation is more important than bond breaking in the transition state (TS). Relatively small activation enthalpy values (11.6 to $14.8kcal{\cdot}mol^{-1}$), the large negative activation entropy values (-29.7 to $-38.7cal{\cdot}mol^{-1}{\cdot}K^{-1}$) and the solvent kinetic isotope effects (SKIE, 2.29, 2.30), the solvolyses of the cyclohexanesulfonyl chloride (1) proceeds via the $S_N2$ mechanism.

용매열처리에 따른 PEDOT:PSS 암모니아 가스 감지막 특성 변화 (Effect of Solvent Annealing on the Characteristics of PEDOT:PSS as a Ammonia Gas Sensor Film)

  • 노왕규;염세혁;이왕훈;신한재;계지원;곽기섭;김세현;류시옥;한동철
    • 센서학회지
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    • 제26권2호
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    • pp.96-100
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    • 2017
  • Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been extensively studied as the active material in ammonia gas sensor because of its fast response time, high conductivity and environmental stability. It is well known that a post annealing process for organic devices based on PEDOT:PSS significantly increases the device performance. In this study, we propose the solvent annealing of PEDOT:PSS and investigated its effects. As a results, post solvent annealing on PEDOT:PSS lead to the surface chemical and physical properties change. These changes result in improved conductivity of the PEDOT:PSS. In additional, ammonia sensitivity of solvent annealed PEDOT:PSS become higher than pristine polymer film. The enhancement is mainly caused by the depletion of gas barrier PSS and structural re-forming PEDOT networks. We believe that the post solvent annealing is a promising method to achieve highly sensitivity PEDOT:PSS films for applications in efficient, low-cost and flexible ammonia gas sensor.

cis-$[Co(en)_2ClNO_2]^+$ 착이온의 가용매 분해반응에 미치는 용매의 영향과 그 반응 메카니즘 (Solvent Effects on the Solvolysis of cis-$[Co(en)_2ClNO_2]^+$ Ion and Its Mechanism)

  • 정종재;박영호
    • 대한화학회지
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    • 제30권1호
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    • pp.3-8
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    • 1986
  • 물-글리세롤, 물-에틸렌 글리콜, 물-이소프로필 알코올 및 물-t-부틸 알코올의 2성분 혼합용매 중에서 cis-$[Co(en)_2ClNO_2]^+$착이온의 가용매 분해반응을 분광광도법으로 연구하였다. 용매의 극성이 커짐에 따라 반응속도도 커지는 경향이 있었으며 반응속도의 대수값과 $\frac{D-1}{2D+1}$값을 도시한 결과 비직선적인 관계를 나타내는 것으로 보아서 용매의 수소결합이나 분산력등의 비정전기적인 상호작용이 지배적으로 작용함을 알 수 있었다. log k와 Grundwald-Winstein의 Y값을 도시한 직선의 기울기와 Kivinen식에서 구한 전이상태에 관여하는 물분자의 수 n값으로부터 실험에 사용한 착물의 가용매 분해반응은 Id메카니즘으로 진행됨을 알았다. 한편 자유에너지 사이클의 결과는 초기상태에서 보다 전이상태에서 용매구조의 효과가 더 큼을 알 수 있었다.

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