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전현표,이상범,Jeon, Hyun-Pyo,Lee, Sang-Beom 배재대학교 자연과학연구소 2005 自然科學論文集 Vol.15 No.1
$LaFeO_3$ 복합산화물과 부분 치환한 $LaFeO_3$ 복합산화물을 citrate와 Cyanide 공침법으로 합성하여 공기중에서 $850^{\circ}C$로 24시간동안 열처리해 제조방법에 의한 영향을 비교하였다. XRD와 IR의 결과에 의하여면, 합성된 산화물은 Orthorhombic의 Perovskite구조를 나타냈으나 B자리에 0.5mol의 Cu가 치환된 복합산화물은 단일상을 얻지 못하였다. 또한, 이들 산화물의 환원반응은 치환하지 않은 $LaFeO_3.17$ 복합산홤루은 2단계 반응인 반면에 치환한 복합산화물은 3단계 반응으로 Dopant에 의한 새로운 환원단계가 존재함을 알았다. $LaFeO_3$ and substituted $LaFeO_3$ mixed oxides were prepared by Citrate and Cyanide method in air $850^{\circ}C$/24h. These oxides of orthorhombic perovskite were characterized by XRD and IR, but substituted $LaFeO_3$ with 0.5mol Cu at B site was not obtained single phase. Also, reduction reaction of un-substituted $LaFeO_3.17$ were two steps but each site substituted oxides were three steps reactions. These means that new reduction step of each site substituted oxides were atributed tot dopant.
전현표,이상범 배재대학교 자연과학연구소 2004 自然科學論文集 Vol.15 No.1
LaFeO_(3) 복합산화물과 부분 치환한 LaFeO_(3) 복합산화물을 Citrate와 Cyanide 공침법으로 합성하여 공기중에서 850℃로 24시간동안 열처리해 제조방법에 의한 영향을 비교하였다. XRD와 IR의 결과에 의하면, 합성된 산화물은 Orthorhombic의 Perovskite구조를 나타냈으나 B자리에 0.5mol의 Cu가 치환된 복합산화물은 단일상을 얻지 못하였다. 또한, 이들 산화물의 환원반응은 치환하지 않은 LaFeO_(3.17) 복합산화물은 2단계 반응인 반면에 치환한 복합산화물은 3단계 반응으로 Dopant에 의한 새로운 환원단계가 존재함을 알았다. LaFeO_(3) and substituted LaFeO_(3) mixed oxides were prepared by Citrate and Cyanide method in air 850℃/24h. These oxides of orthorhombic perovskite were characterized by XRD and IR, but substituted LaFeO_(3) with 0.5mol Cu at B site was not obtained single phase. Also, reduction reaction of un-substituted LaFeO_(3.17) were two steps but each site substituted oxides were three steps reactions. These means that new reduction step of each site substituted oxides were atributed to dopant.
환경배출범주/특수환경배출범주 기반 ECETOC TRA 및 주요/산업/용도 분류체계 이용의 K-CHESAR에 의한 환경예측농도 비교 연구
전현표,양지수,조하나,최은경,김상헌 한국환경보건학회 2023 한국환경보건학회지 Vol.49 No.6
Background: Environmental concentrations of substances can be estimated by K-CHESAR based on main, industrial, and use categories (MC/IC/UC) and ECETOC TRA based on environmental or specific environmental categories (ERC or spERC). Objectives: Three different systems for estimating environmental concentrations were compared to figure out their order with possible reasons along with relationship of regional predicted environmental concentrations (PECregional) and final PEClocal for various uses of a substance. Methods: Typical uses of the case substance and their corresponding ERCs were selected from the webpage of the European Chemical Agency. Proper MC/IC/UC and spERC were assigned to each ERC. Emission fractions were compared for each assessment code from the available database. PECs were calculated by three estimating systems: K-CHESAR using MC/IC/UC, ECETOC TRA using ERC, and ECETOC TRA using spERC with their default values for input parameters. Percentage of PECregional to PEClocal were manually calculated for each use. Results: Emission factors decreased in the order of ERC > MC/IC/UC > spERC. Values of the final PEClocal derived as sum of PECregional and Clocal decreased in the order of calculations using ECETOC TRA-ERC>KCHESAR with MC/IC/UC>ECETOC TRA-spERC for all environmental media. Percentages of PECregional,water to PEClocal,water ranged from 0 to 10.3% in industrial uses calculated with MC/IC/UC and ERC but 96.3 to 100% in wide dispersive uses of ERC and spERC where values of Clocal,water are estimated to be very low. Conclusions: ECETOC TRA generated the most refined PNEC values with spERC and the least with ERC, while K-CHESAR with MC/IC/UC generated values between the two results. The ratio of PECregional to PEClocal can be a good measure for performing suitable estimation of PNECs according to use.
이대은,전현표,김상훈 한국환경보건학회 2016 한국환경보건학회지 Vol.42 No.3
Objectives: Materials coming into contact with food may result in the migration of chemical substances into thefood. To protect consumers from exposure, Regulation (EU) No. 10/2011 specifies the use of standard migrationtests. Polyethylene terephthalate (PET), widely used for food packaging materials, has drawn the attention ofresearchers because unwanted migration of PET into food might occur when consumers reuse packagingmaterial. The aim of this study was to predict and develop a migration model for two components, acetaldehydeand butyraldehyde in PET, into food simulants under conditions of changing pH and solvents, such as thoseobserved in fermented foods like kimchi or sauerkraut. Methods: Using a migration model based on Fick’s second law of diffusion in one dimension, the migration ofacetaldehyde and butyraldehyde from PET into a simulant of fermented food at 20 °C over 10 days wasevaluated. The simulant for fermented food was modelled as 10% ethanol for three days, followed by 3% aceticacid for seven days. Results: The migration of acetaldehyde into the 10% ethanol was 0.36 times that of a simulated fermented foodsystem, while that of butyraldehyde was 1.34 times greater. These results may have been influenced by thechemical interactions among the migrants, polymers and simulants, as well as by the solubilities of the migrantsin polymers and simulants. Conclusion: Because food simulants have a limited capacity to mimic real food systems under the currentmigration model, an appropriate simulant and migration test should be considered in the case of increasingacidity. Furthermore, since the accuracy of the worst-case estimation of migration predicted by the current modelis severely limited under changing food conditions, food simulants and their interactions should be furtherinvestigated with respect to conservative migration modelling.