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        검색결과 2,422

        1671.
        2009.10 KCI 등재 서비스 종료(열람 제한)
        This study was designed to evaluate qualitatively and quantitatively the pollutant compositions, which were emitted from three types of mosquito repellents(MRs)(mat-, liquid-vaporized, and coil-type) by utilizing a 50-L environmental chamber. A qualitative analysis revealed that 42 compounds were detected on the gas chromatography/ mass spectrometer system, and that the detection frequency depended upon chemical types. Nine of the 42 compounds exhibited a detection frequency of 100%. Four aromatic compounds(benzene, ethyl benzene, toluene, and xylene) were detected in all test MRs. The concentration equilibriums in the environmental chamber were achieved within 180 min after sample introduction. The coil-type MR represented higher chamber concentrations as compared with the mat- or liquid-vaporized-type MR, with respect to the target compounds except for naphthalene. In particular, the chamber concentrations of ethyl benzene, associated with the use of coil-type MR, were between 0.9 and 65 mg m-3, whereas those of mat- and liquid-vaporized-type MRs were between 0.5 and 2.0 mg m-3and 0.3 and 1.4 mg m-3, respectively. However, naphthalene concentrations in the chamber, where a liquid-vaporized-type MR was placed, were measured as between 17.8 and 56.3 mg m-3, but not detected in the chamber, where a mat- or coil-type MR was placed. The empirical model fitted well with the time-series concentrations in the environmental chamber(in most cases, determination coefficient, R2 ≳ 0.9), thereby suggesting that the model was suitable for testing emissions. In regards to the target compounds except for benzene, although they were emitted from the MRs, health risk from individual exposure to them were estimated not to be significant when comparing exposure levels with no observed adverse exposure levels or lowest observed adverse exposure levels of corresponding compounds. However, it was concluded that the use of MRs could be an important indoor source as regards benzene.
        1672.
        2009.10 KCI 등재 서비스 종료(열람 제한)
        In this study, the environmental behavior of malodor pollutants (MPs: H2S, CH3SH, DMS, and DMDS) was investigated around areas influenced by strong anthropogenic processes based on observations and modeling study (a CALPUFF dispersion model). The MP emission concentrations were measured from 8 industrial source regions (tire plants (S1-S3), waste water disposal plant (S4), and oil refinery (S5) in an urban center area and paper mill/incineration plant (S6) and livestock feedlots (S7-S8) in Ungsang area) in Yangsan city during a fall period in 2008 (21 October 2008). Overall, the most MPs emitted from the urban center area were found to affect the malodor pollution in their downwind areas during early morning (06:00 LST) and nighttime (18:00 and 21:00 LST), compared with those in the Ungsang area. For malodor intensity, the most MPs in the urban center area (especially S1 and S2) were found to be a significant contributor, whereas CH3SH and H2S in the Ungsnag area (especially S6) were the dominant contributor. The model study showed agreement in the spatial distributions of simulated MPs with those of the observations. The largest impact of MPs in the urban center area on the malodor pollution in its residential areas occurred at S1, S2, and S3 sites during nighttime, while that of MPs in the Ungsang area occurred at S6 and S8 sites. This may be caused mainly by the high MP emissions and in part by wind conditions (prevailing northeasterly winds with low wind speeds of 2-3 m/s).
        1673.
        2009.10 KCI 등재 서비스 종료(열람 제한)
        기내배양을 이용하여 Pteris cretica 'Wilsonii'의 효율적인 대량번식법을 개발하기 위한 목적으로 근경, 엽신 및 엽병조직으로부터 식물체 재분화를 유도하였다. 그 결과, 균질화된 근경의 절편에서만 신초가 재생되었다. 식물체 재분화를 유도하는데 적합한 배지는 1%의 sucrose와 50 mg·mL-1의 NaH2PO4를 첨가한 1/8MS배지였다. 근경 절편으로부터 식물체의 재생을 촉진하기 위하여 생장조절물질이 첨가된 배지에서 2달 동안 절편을 배양한 후, 생장조절물질을 첨가하지 않은 배지로 이식한 결과, 1μm의 kinetin과 5μM의 NAA를 혼용첨가한 처리구에서 신초의 재생이 가장 왕성하였다. BA 첨가구에서는 분열조직의 일종인 GGB가 다량 유도되었으나, 형성된 GGB에서 신초 재생율은 낮은 것으로 나타났다. MS배지의 적정 무기물 및 비타민의 농도를 구명하는 실험을 마친 뒤, 형성된 유묘를 이용하여 기외순화 시킨 결과, 1/8MS배지에서 형성된 유묘가 생존율이 가장 높았으며, 생육 또한 왕성하였다.