Monte-Carlo 모의실험을 통한 부분 인구집단별 벤젠 및 PM 10 의노출 및 위해성 평가

박진현(Jinhyeon Park),양소영(So Young Yang):박윤경(Yunkyung Park),류현수(Hyeonsu Ryu),김은채(Eunchae Kim),최영태(Youngtae Choe),허 정(Jung Heo),조만수(Mansu Cho),양원호(Wonho Yang) 한국환경보건학회 2019 한국환경보건학회지 Vol.45 No.3

Objectives: The Korea Ministry of Environment regulates concentrations of hazardous air pollutants (HAPs) through Atmosphere Environmental Standards to protect public health from HAPs. However, simply determining the exceedance of HAP concentrations has several limitations and more comprehensive assessment is required. In addition, integrated risk assessment is needed considering exposure in all microenvironments, including outdoor as well as indoor environments. The purpose of this study was to assess the differences in risk by sub-population groups according to time-activity patterns and reported concentrations, as well as the lifetime risk for Koreans. Methods: In this study, we calculated time-weighted average exposure concentrations for benzene and PM 10 among preschool-age children, students, housewifes, workers, and the elderly using residential time and concentrations for indoor (house, school or workplace, other), outdoor, and transport by the meta-analysis method. The risk assessments were conducted by excess cancer risk and disease death risk using 1,000,000 Monte-Carlo simulations for probabilistic analysis. Results: Preschool-age children, students, housewifes, workers, and the elderly spent 91.9, 86.0, 79.8, 82.2, and 77.3% of their day in their house, workplace, or school, respectively. The more than 99% excess cancer risk for benzene exceed 1.0E-06 in all sub-populations and lifetime. The acute disease death risk for PM 10 for housewifes and workers for lifetime were 3.35E-04 and 3.18E-04, and chronic disease death risks were 2.84E-03 and 2.70E-03, respectively. Conclusions: The risk of benzene and PM 10 by sub-population group and for the lifetime of housewifes and workers were assessed. Benzene showed risky results for this study. All disease death risks of PM 10 were higher than 1.0E-04 and showed different risks by sub-population. This study can be used as a basis for lifetime exposure and risk assessment to benzene and PM 10 .

Design Concept for an Interactive Online VR Experience to Encourage Donation

Eunchae Lee(이은채),Sohee Park(박소희),WhiJae Kim(김휘재),Mingu Lee(이민구) 한국디자인학회 2020 한국디자인학회 학술발표대회 논문집 Vol.2020 No.6

Electrochemical Behaviors of UCl3 and CrCl2 in NaCl-MgCl2 Salt (Program for Fostering Convergence of Human Resources in Back-end Nuclear Fuel Cycle)

Eunchae Sim,Yujin Kim,Youngjae Yang,SungJun An,Jun Woo Park,Jong-Il Yun 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

Molten chloride salts have received considerable research attention as potential nuclear fuel and coolant candidates for molten salt reactors. However, there are several challenges, especially for structural materials due to the selective dissolution of chromium (Cr) in the molten chloride salts environment. Understanding the compatibility of uranium (U), which is used as nuclear fuel in molten salt reactors, with Cr in molten chloride salts is critical for designing the molten salt reactor structure. Therefore, in this study, the cyclic voltammetry (CV) was used to investigate the electrochemical behaviors of U and Cr. The diffusion coefficients and formal potentials were obtained. The electrochemical properties of uranium and chromium were investigated by CV in molten NaCl-MgCl2 salt at 600°C. Tungsten rods for working and counter electrode, and Ag/AgCl for reference electrode were utilized in this experiment. UCl3 made from the chemical dissolution of U rods and CrCl2 (Sigma-Aldrich, 99.99%) were used. Diffusion coefficients (D) of U and Cr were calculated by measuring reduction peak current of U3+/U and Cr2+/Cr from CV curves and using the Berzins-Delahay equation; D (U3+/U) = 3.0×10-5 cm2s-1 and D (Cr2+/Cr) = 3.3×10-5 cm2s-1. The formal potentials were also calculated by using the reduction peak potential obtained from CV results; E0’ (U3+/U) = -1.173 V and E0’ (Cr2+/Cr) = -0.321 V. The ionization tendency was investigated by comparing each reduction peak potential. The reduction peak potential Ep,c was increasing order of Ep,c (U3+/U) < Ep,c (Cr2+/Cr) < Ep,c (U4+/U3+). It can be seen that in the presence of U4+ and Cr metals, the Cr in the alloy can dissolve into Cr2+, but in the presence of U3+ and Cr metals, the Cr in the alloy does not dissolve into Cr2+. By analyzing the CV curve, diffusion coefficients and formal standard potentials were obtained. The result of comparing reduction peak potentials suggests that the nuclear fuel using U4+ should be inhibited to prevent the selective dissolution of Cr.

화학사고 대응을 위한 시간별 급성노출기준 참고치 산정 : 폼알데하이드 사례

김은채(Eunchae Kim),조용성(Yong-Sung Cho),이청수(Chung-Soo Lee),양원호(Wonho Yang),황승율(Seung-Ryul Hwang),박지훈(Jihoon Park) 한국환경보건학회 2021 한국환경보건학회지 Vol.47 No.2

Objectives: This study aimed to provide temporal Acute Exposure Guideline Levels (AEGL) for a hazardous substance as a pilot study. Methods: As one of the substances designated by the Korea Ministry of Environment as requiring preparations for potential accidents, formaldehyde was selected to estimate the AEGLs. The calculation was based on Haber’s formula (Cn ×t=k) using valid toxicity data (for humans/animals). A total of 96 points of AEGL levels were provided using an interval of five minutes over eight hours. Results: The AEGL-1 and 2 values were constant for the entire exposure duration at 0.9 ppm and 14 ppm, respectively. The values were obtained from clinical/animal tests, and the adaptation effect after a given exposure duration was also considered. AEGL-3 was based on animal toxicity data, and it was estimated from 127 ppm for the initial five minutes to 35 ppm for eight hours. Conclusions: More specific AEGL levels for formaldehyde could be obtained in this study using toxicity data with Haber’s formula. Based on this methodology, it would be also possible to estimate AEGL levels that can be used at the scene of a chemical accident for other substances requiring preparation for potential accidents.

Designing an Application for Sharing Photographs of Art Exhibitions with a Matching Network to Stimulate Indirect Visitor Experience

Sohee Park(박소희),Eunchae Lee(이은채),Mingu Lee(이민구) 한국디자인학회 2020 한국디자인학회 학술발표대회 논문집 Vol.2020 No.6

PHMG (polyhexamethylene guanidine) 흡입독성참고치 산출을 통한 가습기살균제 노출등급 분류 및 특성

김은채(Eunchae Kim),류현수(Hyeonsu Ryu),박진현(Jinhyeon Park),최영태(Youngtae Choe),허정(Jung Heo),이슬아(Seula Lee),조은경(Eun-Kyung Jo),최윤형(Yoon-Hyeong Choi),조만수(Mansu Cho),양원호(Wonho Yang) 한국환경보건학회 2020 한국환경보건학회지 Vol.46 No.3

Objectives: The Korean Ministry of Environment has identified cases of people suspected of suffering lung disease potentially caused by polyhexamethylene guanidine (PHMG) used in humidifier disinfectants (HDs). Exposure assessment for the HDs was conducted using a questionnaire during face-to-face interview. The main purposes of this study were to develop a methodology to effectively classify levels of exposure to HDs based on a questionnaire. Methods: We first identified the overall participants’ exposure characteristics by HD exposure levels; Second, we selected misclassified subjects and investigated characteristics of overestimated and underestimated subjects, focusing on exposure cases to PHMG-containing HDs. An inhalation reference concentration (RfC) for PHMG was produced on the basis of inhalation toxicity values. We made a cross-tabulation of the exposure classes (Exposure classes 1-to-4) by clinical classes based on the RfC. When the value of the exposure class minus the clinical class was 0 or 1, we assumed these were true values. When the value was ≥2 and ≤ −2, we assigned these cases to the overestimation group and underestimation group, respectively. Results: The overestimated group may have already recovered and responded excessively due to psychological anxiety or in order to receive compensation. On the other hand, relatively high mortality rates and surrogate responses for those under 10 years of age may have resulted in inaccurate exposure assessment for underestimated groups. For the characteristics of exposure, it was shown that for the underestimated group, the exposure was relatively weaker than the overestimated group, even though a high overall clinical rating was determined. Conclusions: This study may suggest ways to reduce bias and overcome the limitations of current HD exposure assessment.

시간활동양상에 따른 주택의 시간대별 실내·실외 초미세먼지 농도비

박진현(Jinhyeon Park),김은채(Eunchae Kim),최영태(Youngtae Choe),류현수(Hyoensu Ryu),김순신(Sunshin Kim),우병렬(Byung Lyul Woo),조만수(Mansu Cho),양원호(Wonho Yang) 한국환경보건학회 2020 한국환경보건학회지 Vol.46 No.5

Objective: The purpose of this study was to evaluate the indoor to outdoor ratio (I/O ratio) of time activity patterns affecting PM2.5 concentrations in homes in Korea through a simulation. Methods: The time activity patterns of homemakers were analyzed based on the ‘Time-Use Survey’ data of the National Statistical Office in 2014. From September 30 to October 2, 2019, the experimenter lived in multi�family housing located in Guro-gu, Seoul. The I/O ratio of PM2.5 concentration was measured by installing sensor-based instruments. Results: The average indoor and outdoor PM2.5 concentrations during the three days were 33.1±48.9 and 45.9±25.3 μg/m3 , respectively. The average I/O ratio was 0.75±0.60. The indoor concentration tended to increase when PM2.5 source activity such cooking and cleaning was present and outdoor PM2.5 was supplied through ventilation. Conclusions: This study could be used as basic data for estimating indoor PM2.5 concentrations with personal activity pattern and weather conditions using outdoor concentrations.

Gene expression is related with transcription memory in mammary gland

Sumin Oh,Eunchae Park,Sungju Jung,Su Min Yoon,Yeeun Jo,Seyeong Kim,Kyung Hyun Yoo 한국실험동물학회 2019 한국실험동물학회 학술발표대회 논문집 Vol.2019 No.7

Effects of feeding starch sugar by-products on in situ rumen disappearance rate, growth performance, and carcass characteristics of late finishing Hanwoo steers

Choi Yongjun,Park Geetae,강효곤,안지연,Lee Eunchae,Na Youngjun,이상락 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.2

Objective: The aim of this study was to determine the effects of feeding starch sugar byproducts (SSBs) on in situ disappearance rate, performance, and carcass characteristics of Hanwoo steers in the late finishing stage. Methods: To determine the in situ disappearance rate, nylon bags filled with 5 g of SSB were inserted into the ventral sac of two cannulated Holsteins cows and incubated for 0, 2, 4, 8, 16, 24, and 48 h. A total of 30 Hanwoo steers were fed the experimental diets, which were basal diet (control) and 7% SSB on an as-fed basis (4.35% dry matter [DM]), formulated according to requirements of the Korean Feeding Standard for Hanwoo. The experiment was conducted over 80 days using a completely randomized block design. Results: Soluble fraction a of DM and organic matter (OM) was 44.20% and 64.60% DM, fraction b was 23.00% and 19.40% DM, and c values (the rate of degradation of fraction b) were 0.04 and 0.04/h, respectively. The effective degradability of DM at rumen solid outflow rates of 0.02, 0.05, and 0.08/h was 59.83, 54.75, and 52.16, respectively, and for OM was 77.78, 73.52, and 71.34, respectively. Initial and final body weight, average daily gain, DM intake, and gain:feed did not differ significantly between control and SSB groups during the entire experimental period. Carcass traits of Hanwoo steers with SSB supplementation were not significantly different between treatments except for dressing percentage, which was greater with SSB treatment. The content of saturated fatty acid (SFA) was greater and that of unsaturated fatty acids (UFA) was lower in the SSB group than in the control group. The ratio of UFA to SFA was significantly lower in the SSB group than in the control group. Conclusion: A total mixed ration containing less than 4.0% DM of SSBs can be used in Hanwoo steers without a decrease in productivity and carcass traits. Objective: The aim of this study was to determine the effects of feeding starch sugar by-products (SSBs) on in situ disappearance rate, performance, and carcass characteristics of Hanwoo steers in the late finishing stage.Methods: To determine the in situ disappearance rate, nylon bags filled with 5 g of SSB were inserted into the ventral sac of two cannulated Holsteins cows and incubated for 0, 2, 4, 8, 16, 24, and 48 h. A total of 30 Hanwoo steers were fed the experimental diets, which were basal diet (control) and 7% SSB on an as-fed basis (4.35% dry matter [DM]), formulated according to requirements of the Korean Feeding Standard for Hanwoo. The experiment was conducted over 80 days using a completely randomized block design.Results: Soluble fraction a of DM and organic matter (OM) was 44.20% and 64.60% DM, fraction b was 23.00% and 19.40% DM, and c values (the rate of degradation of fraction b) were 0.04 and 0.04/h, respectively. The effective degradability of DM at rumen solid outflow rates of 0.02, 0.05, and 0.08/h was 59.83, 54.75, and 52.16, respectively, and for OM was 77.78, 73.52, and 71.34, respectively. Initial and final body weight, average daily gain, DM intake, and gain:feed did not differ significantly between control and SSB groups during the entire experimental period. Carcass traits of Hanwoo steers with SSB supplementation were not significantly different between treatments except for dressing percentage, which was greater with SSB treatment. The content of saturated fatty acid (SFA) was greater and that of unsaturated fatty acids (UFA) was lower in the SSB group than in the control group. The ratio of UFA to SFA was significantly lower in the SSB group than in the control group.Conclusion: A total mixed ration containing less than 4.0% DM of SSBs can be used in Hanwoo steers without a decrease in productivity and carcass traits.

사회성 능력이 인공지능 챗봇의 사회적 사용과 자기노출에 미치는 영향 : 사용자의 외로움 정도와 챗봇에 대한 지각된 인간다움의 매개효과

박남기(Namkee Park),김윤경(Yoonkyoung Kim),장은채(Eunchae Jang),이주연(Juyeon Lee),최어진(Eojin Choi) 한국언론학회 2021 한국언론학보 Vol.65 No.5

The present study examined the effects of social competence on the social use of artificial intelligence (AI) chatbots and self-disclosure to chatbots, highlighting the mediating roles of loneliness and perceived Humanlikeness of chatbots. An online survey was conducted with a total of 645 participants who had used AI chatbots. Results showed that people who possessed a high level of social competence tended to use AI chatbots more socially, and this association was mediated by chatbot users loneliness and perceived humanlikeness of chatbots, in such order (serial mediation effect). As for self-disclosure to chatbots, the effect of social competence on self-disclosure was not significant. However, the mediation effect through perceived humanlikeness and the serial mediation effect through loneliness and perceived humanlikeness were significant. Specifically, people who possessed a high level of social competence felt less loneliness, but the low level of loneliness increased perceived humanlikeness toward chatbots, which in turn led to more social use of chatbots as well as more self-disclosure to chatbots. The study has both theoretical and practical implications. The study sheds light on the effects of social competence in the context of human-AI interaction, supporting the computers as social actors (CASA) perspective. Further, the positive effect of perceived humanlikeness of chatbots offers practical implications for AI chatbot developers. Limitations and suggestions for future studies are discussed.