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        검색결과 595

        121.
        2013.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The children of daycare center are sensitive to indoor environmental pollution. This study was a preliminary investigation for improving the environmental and healthy quality of daycare centers. The sampling of sites in daycare centers was undertaken three times such as day-morning (10:00-12:00), afternoon (16:00-20:00), following dawn (04:00-08:00)-at 21 daycare centers located in Seoul, Korea from April, 2012 to July, 2012. The mean concentrations of TVOC were 255.2, 217.0, and 439.4 μg/m3 at morning, afternoon, and following dawn, respectively. The daycare center indoor/outdoor ratios on the most targeted volatile organic compounds were above 1.0 except that for carbon tetrachloride, which was almost 1.0. Significant correlations (p<0.01) were observed between indoor and outdoor carbon tetrachloride, which implies that indoor carbon tetrachloride could be largely accounted for by outdoor sources. The other targeted indoor volatile organic compounds such as benzene, toluene, ethylbenzene, styrene, xylenes, chloroform showed no significant correlations with that of outdoor.
        4,600원
        122.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was investigated the chemical composition from Syneilesis palmata essential oil and the tendency of variation of the sesquiterpene compounds according to the harvesting time. The essential oils obtained by hydro distillation from the aerial parts of Syneilesis palmata were analyzed by GC and GC-MS. Ninety-eight compounds consisting of 9 aliphatic hydrocarbons, 17 sesquiterpene hydrocarbons, 11 aliphatic aldehydes, 1 terpene aldehyde, 8 aliphatic alcohols, 4 monoterpene alcohols, 16 sesquiterpene alcohols, 3 diterpene alcohols, 6 ketones, 11 esters, 8 oxides and epoxides, 3 acids and 1 miscellaneous one were identified from the oil. Spathulenol (22.33%) was the most abundant compound, followed by β- caryophyllene (6.23%), germacrene D (5.57%), longipinane (4.10%), and epiglobulol (3.65%). The volatile composition of Syneilesis palmata was characterized by higher contents of sesquiterpene compounds, especially sesquiterpene alcohols. The total content of 13 sesquiterpene compounds was decreased significantly from 2010 to 2012. α-Caryophyllene, β-bisabolene, elemol, germacrene D, β-zingiberene, longipinane, and β-caryophyllene alcohol contents decreased, while β-bisabolol content increased during 3 years. The ecological responses to recent climate change may be influenced in the chemical components of natural plant terpenoids.
        4,000원
        124.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        다성분계 휘발성 유기화합물(VOCs; Volatile Organic Compounds)의 분리를 위하여 상전이법을 이용하여 방사 한 poly (ether imide) (PEI) 중공사 지지체에 poly (dimethylsiloxane) (PDMS)를 코팅하여 중공사 복합막을 제조하였다. VOCs 회수용 중공사막으로서 적합성을 알아보기 위해서 중공사막의 모폴로지, 질소 및 산소 기체 투과도를 측정하고, 벤젠, 톨루엔 그리고 자일렌에 대한 내구성을 조사하였다. 다성분계 휘발성 유기화합물의 효과적인 분리성능을 조사하기 위하여 Stage-cut과 feed 농도에 따른 다성분계 VOCs 투과 성능 변화를 관찰하였다. PEI 지지체 중공사막에 PDMS를 코팅시킴 에 따라 산소와 질소 투과도는 각각 45,000 GPU와 49,450 GPU에서 63 GPU와 30 GPU로 감소하는 것을 확인하였다. VOCs 투과농도는 Stage-cut이 감소함에 따라 증가하나, 회수율은 감소하였다. 반면에 공급농도 증가에 따라 투과농도는 비례적으로 증가하였지만, 농축비나 회수율은 큰 변화가 없었다.
        4,000원
        125.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        도장공정에서 발생되는 휘발성 유기화합물의 회수를 위하여 중공사 분리막 모듈을 이용한 공정을 준비하여, 공급 압력과 시간변화에 따른 휘발성 유기화합물의 회수에 대한 특성평가를 실시하였다. 중공사 분리막 모듈을 도장공정에 직접 적용한 결과, 투과된 휘발성 유기화합물의 농도는 투과시간과 압력의 증가됨에 따라 증가되었으며, 단일공정보다 다단공정이 더 우수한 분리성능을 나타내는 것을 확인하였다.
        4,000원
        127.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        유기전기발광 소자에서 천연색을 구현하기 위해서는 적색, 녹색, 청색 발광물질이 필요하다. 그러나 적색과 녹색의 발광 물질에 대한 연구는 매우 활발하나 청색의 물질에 대한 연구가 미흡한 것은 높은 발광 에너지 때문으로 보인다. 본 연구는 발광 효율이 높으며 열적 안정성이 좋은 화합물을 합성하려는 것으로 carbazole로 치환된 anthracene 화합물 합성에 관한 것이다. Tert-butyl 기로 치환된 carbazole에 전기 발광 성질과 열적 안정도가 좋은 anthracene을 직접 결합시킴으로써 정공전달 특성을 갖는 작용기와 전자전달 특성을 갖는 작용기 간의 거리에 대한 연구를 시작하고자 하였다.
        4,000원
        128.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Excellent electron transport properties with enhanced light scattering ability for light harvesting have made well-ordered one dimensional TiO2 nanotube(TNT) arrays an alternative candidate over TiO2 nanoparticles in the area of solar energy conversion applications. The principal drawback of TNT arrays being activated only by UV light has been addressed by coupling the TNT with secondary materials which are visible light-triggered. As well as extending the absorption region of sunlight, the introduction of these foreign components is also found to influence the charge separation and electron lifetime of TNT. In this study, a novel method to fabricate the TNT-based composite photoelectrodes employing visible responsive CuInS2 (CIS) nanoparticles is presented. The developed method is a square wave pulse-assisted electrochemical deposition approach to wrap the inner and outer walls of a TNT array with CIS nanoparticles. Instead of coating as a dense compact layer of CIS by a conventional non-pulsed-electrochemical deposition method, the nanoparticles pack relatively loosely to form a rough surface which increases the surface area of the composite and results in a higher degree of light scattering within the tubular channels and hence a greater chance of absorption. The excellence coverage of CIS on the tubular TiO2 allows the construction of an effective heterojunction that exhibits enhanced photoelectrochemical performance.
        4,000원
        129.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Swine manure discharged from pigery emits various odorous compounds. The most common method to reduce such odors is adding feed additives to swine feeds. However, whether the effects of such methods are truly effective are controversial. This research contrasts the aldehyde compound emission characteristics and removal effects from a treatment group, which were given feeds added with feed additives, to a control group, which were given feeds without feed additives. Sixty swine of age 26~28 days were evenly divided into six sections within an incubator type pigsty - each section contained ten weaners. Five types of feed additives, either currently in the market or in development were supplied. Gases sampled from the headspace in the odor producing reactor were analyzed by GC. Major malodorous compounds were estimated by the concentrations and threshold values from the detected components. Since 95.3% of the odor comes from isobutyraldehyde out of six types of aldehyde compounds (acetaldehyde, propionaldehyde, isobutyraldehyde, n-butyraldehyde, i-valeraldehyde, n-valeraldehyde), it can be regarded as the most critical compound contributing to pigsty odor. Aldehyde compounds showed statistically significant correlation with elimination of sulfide compounds and trimethylamine
        4,000원
        130.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to evaluate the relationship with the concentration and odor intensity using the odor sensory method for 4 types of sulfur compounds, ammonia, and trimethylamine. For the measurement, 13 panelists were selected by several criteria through a panel test. Panelists chosen for their closely similar sensitivities provide more reproducible values. The estimation showed that the correlation of the concentration with odor intensity for the 6 compounds can be reasonably expressed by the equation I=Aㆍlog C+B (I: Odor Intensity, C: material concentration, A: material constant, B: constant). The result of this study is suggested to be used as a base data for research on measures to improve the regulation standards for complex odor concentration on site boundary in operation, as well as a correlation between the concentration and odor intensity for the designated foul odor substances, and their characteristics.
        4,000원
        131.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벤질리덴아세톤(benzylinedeneacetone: BZA)은 두 곤충병원세균인 Xenorhabdus nematophila와 Photorhabdus temperata subsp. temperata에서 유래된 대사산물의 일종이다. 이 물질은 곤충의 세포성 및 체액성 면역반응을 억제하며 또한 다양한 세균이나 곰팡이에 대해 항생효과를 갖고 있다. 그러나 이 물질이 갖는 비교적 높은 약해와 낮은 식물체 침투력은 효과적 농약으로 개발하는 데 어려움을 주고 있다. 본 연구에서는 다섯 개의 서로 다른 BZA 유사체를 스크리닝하여 면역억제 및 항균활성을 유지하면서 비교적 용해도가 높고 약해가 낮은 물질을 선발하였다. BZA의 벤젠 고리에 수산기가 붙은 유도체는 면역억제 및 항균활성이 뚜렷이 낮아졌다. 또한 BZA의 케톤기를 카르복실기로 변형하면 면역억제와 항균활성을 잃게 되었다. 그러나 BZA의 탄화수소 사슬을 짧게 하여 형성된 아세테이트 유도체인 4-hydroxyphenylacetic acid (HPA)는 면역억제와 항균활성을 잃지 않았다. 또한 HPA는 BZA 보다 고추(Capsicum annuum)에 대해 약해가 낮은 것으로 나타났다. 이 연구는 낮은 약해를 유발하면서 높은 곤충면역억제와 식물병원균에 대해 높은 항균활성을 보이는 BZA 유도체를 선발하였다.
        4,000원
        132.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리는 순환전압전류법에 의한 LB 필름에 대한 전기화학적 특성을 조사하였다. 인지질 화합물은 ITO glass에 Langmuir-Blodgett법을 사용하여 제막하였다. 0.5, 1.0, 1.5 및 2.0 N NaClO4 용액에서 3 전극 시스템 (Ag/AgCl 기준전극, 백금선 카운터 전극 및 LB 필름이 코팅된 ITO 작업전극)으로 순환전압전류법을 사용하여 전기화학적 측정을 시도하였다. 측정 범위는 연속적으로 1650 mV로 산화시키고, 초기전위인 -1350 mV로 환원시켰다. 그 결과, 인지질 화합물의 LB 필름은 순환전압전류도표로부터 오직 산화전류로 인한 비가역공정으로 나타났다. LB 필름의 확산계수(D) 효과는 인지질 화합물 양의 증가로 인하여 감소하였다.
        4,000원
        133.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
         ,  , The larvicidal activities of Piper nigrum fruit methanol extracts and its constituents against larvae of the diamondback moth, Plutella xylostella, were investigated using the leaf dipping method. Administering the P. nigrum methanol extract resulted in 100 and 97% mortality against diamondback moth larvae at 5.0 and 2.5 mg/mL concentrations, respectively. Larvicidal activities of the P. nigrum fruit-derived piperidine alkaloids, piperine, and N-isobutylamide, as well as pellitorine, guineensine, pipercide, and retrofractamide A against P. xylostella varied according to test compound. Based on the 48 h LC50 values, the most toxic compound to diamondback moth larvae was guineensine (0.013 mg/mL) followed by retrofractamide A (0.020mg/mL), pipercide (0.033mg/mL), and pellitorine (0.046 mg/mL). The LC50 value of piperine was >, 0.5 mg/mL.
        3,000원
        134.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to evaluate the relationship with the concentration and dilution factor using the Air Dilution Olfactory Method, which is suggested in the Standard Method of Odor Compounds, by measuring dilution factor for 4 types of sulfur compounds, ammonia, and trimethylamine. For the measurement, 13 panelists were selected by several criteria through a panel test. Panelists chosen for their closely similar sensitiviyies provide more reproducible values. The estimation showed that the correlation of the concentration with dilution factor for the 6 compounds can be reasonably expressed by the equation logC=AfㆍlogD+F (Af: material costant, F: constant). The result of this study is suggested to be used as a base data for research on measures to improve the regulation standards for complex odor concentration on site boundary in operation, as well as a correlation between the concentration and dilution factor for the designated foul odor substances, and their characteristics.
        4,000원
        136.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper analyzes phenolic compounds, carbon isotopes, and sugar components of whiskys based on the maturation period. For this, the paper considers a total of 40 whiskys(mainly imports) distributed in Korea. It is important to analyze the presence phenolic compounds(e.g., furfural, syringaldehyde, vanillin, syringic acid, and vanillic acid) because these are found only in whiskys ripened in oak. The results indicate that the total content of phenolic compounds increased with the increase in the storage period regardless of the type of whisky. In terms of vanillin/syringaldehyde(V/S), Scotch whiskys had 0.4~0.5; American whiskies, 0.30~0.34; and Canadian whiskies, 0.31~0.33. In terms of Scotch whiskys, Macallan had 0.25~0.34, making it unique among Scotch whiskys. In terms of the ratio of carbon isotopes, there were clear differences between malt Scotch whiskys, blended Scotch grain whiskys, American whiskys, and Canadian whiskys: -23.4~-24.3, -16.8~-21.0, -11.0~-11.5 and -9.5~13.9, respectively. In addition, malt Scotch whiskys contained 40~230 ㎎/ℓ of fructose; blended Scotch whiskys, 20~120 ㎎/ℓ; American whiskys, 50~70 ㎎/ℓ; and Canadian whiskys, 20~100 ㎎/ℓ, demonstrating that the fructose content of single-malt whiskys was twice the average fructose content. On the other hand, malt Scotch whiskys contained 30~170 ㎎/ℓ of glucose; blended Scotch whiskys, 20~120 ㎎/ℓ; American whiskys, 20~30 ㎎/ℓ; and Canadian whiskys, 10~110 ㎎/ℓ, demonstrating that the glucose content of single-malt whiskys exceeded the average glucose content. This study’s results can be used as a database of classification for whiskys based on the fermentation of raw ingredients and the period of maturation for distinguishing between different types of whiskys. In addition, the results can facilitate the verification of genuine whiskys by allowing for the identification of different types of whiskys based on the period of maturation.
        4,000원
        137.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effect of difference in gas phase media (between nitrogen and air) used for standard gas preparation was evaluated with respect to relative recovery of carbonyl compounds (CC). To this end, calibration analysis was carried out using gaseous CC standards (with the two media) containing five different CCs (acetaldehyde (AA), propionaldehyde (PA), butyraldehyde (BA), isovaleraldehyde (IA), and valeraldehyde (VA)). Derivatization of CCs was made, and the carbonyl hydrazones eluted via acetonitrile were analyzed by reverse phase HPLC for UV detection. As a result, the CC standards in N2 medium showed about 10% higher recovery than that of air medium. However, the difference in their relative recovery is in most cases not statistically significant. Consequently, it is concluded that the difference in gaseous media like N2 or air is unlikely to affect derivatization efficiency of CCs.
        4,000원
        138.
        2011.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        A bake-out process using auto switchgear was carried out to evaluate the reduction effect of the concentration of volatile organic compounds (VOCs) and formaldehyde in newly-built apartments for seven days. The reduction rate of VOCs was observed as followings: 19%, 38%, 89%, 90%, and 96% for benzene, toluene, ethylbenzene, xylene, and styrene, respectively, which satisfies at the indoor air quality standards of newly-built apartment houses in Korea. The reduction rate of formaldehyde was 75%. Those results proved that the bake-out process using auto switchgear was effective for reducing indoor air pollutants.
        4,000원
        139.
        2011.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        There has been a growing concern about the emissions of formaldehyde and VOCs from automotive interior materials which could have an important impact on the in-vehicle air quality(IVAQ) of automotive vehicles. Many leading automobile manufacturers have now introduced their own specification standards for testing and limiting emissions from products produced by their suppliers. In addition, ISO (International Standard Organization) has been established ISO 12219-1, 2, 3, 4, 5 to determine the emissions of volatile organic compounds from automotive vehicle. The objective of this paper is to compare the area specific emission rates determined from surface emissions testing using the microchamber(MC) in comparison with a 1 m3 emission test chamber(ETC) operated in accordance with ISO 12219-3, ISO 12219-4. Measured emission concentrations in absolute terms were different between Microchamber and 1 m3 chamber. However, qualitative comparison of the chromatograms shows that the Microchamber is able to perform a screening test
        4,300원
        140.
        2011.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was to assess the lifetime cancer and non-cancer risk on exposure to volatile organic compounds This study was assessed the lifetime cancer and non-cancer risk of volatile organic compounds (VOCs) exposure in young children at elementary-schools and academies in Korea. The samples were collected at children's facilities (50 elementary-schools and 42 academies) in summer (Aug ~ Sept, 2008), winter (Dec 2008 ~ Feb, 2009) and Spring (Mar ~ Apr, 2009) periods, and analyzed by GC-MSD. We estimated the lifetime excess cancer risks (ECRs) of benzene and the hazard quotients (HQs) of non-carcinogens toluene, ethylbenzene, xylene and styrene. In addition, for carcinogens, the excess cancer risk (ECR) was calculated by considering the process of deciding cancer potency factor (CPF) and age dependent adjust Factor (ADAF) from the data in adults. The average ECRs of benzene for young children were 1×10-7~1×10-9 level in all facilities. HQs of four non-carcinogens did not exceed 1.0 for all subjects in all facilities.
        4,300원