Sorption and Desorption Kinetics of Naphthalene and Phenanthrene on Black Carbon in Sediment

오상화,송동익,신원식,Oh, Sang-Hwa,Wu, Qi,Song, Dong-Ik,Shin, Won-Sik Korean Society of Soil and Groundwater Environment 2011 지하수토양환경 Vol.16 No.6

Black carbon (BC), a kind of high surface area carbonaceous material (HSACM), was isolated from Andong lake sediment. Sorption and desorption kinetics of naphthalene (Naph) and phenanthrene (Phen) in organic carbon (OC) and BC in the Andong lake sediment were investigated. Several kinetic models such as one-site mass transfer model (OSMTM), two-compartment first-order kinetic model (TCFOKM), and a newly proposed modified two-compartment first-order kinetic model (MTCFOKM) were used to describe the sorption and desorption kinetics. The MTCFOKM was the best fitting model. The MTCFOKM for sorption kinetics showed that i) the sorbed amounts of PAHs onto BC were higher than those onto OC, consistent with BET surface area; ii) the equilibration time for sorption onto BC was longer than those onto OC due to smaller size of micropore ($11.67{\AA}$) of BC than OC ($38.18{\AA}$); iii) initial sorption velocity of BC was higher than OC; and iv) the slow sorption velocity in BC caused the later equilibrium time than OC even though the fast sorption velocity was early completed in both BC and OC. The MTCFOKM also described the desorption of PAHs from the OC and BC well. After desorption, the remaining fractions of PAHs in BC were higher than those in OC due to stronger PAHs-BC binding. The remaining fractions increased with aging for both BC and OC.

광미내 Zn의 탈착 특성과 지렁이에 대한 생이용성

오상화,신원식,Oh, Sang-Hwa,Shin, Won-Sik 한국지하수토양환경학회 2011 지하수토양환경 Vol.16 No.4

Sorption and sequential desorption experiments were conducted for Zn using a natural soil (NS) in background status by aging (1, 30 and 100 days). The sorption isotherm showed that Zn had high sorption capacity but low sorption affinity in NS. Sequential desorption was biphasic with appreciable amount of sorbed Zn residing in the desorption-resistant fraction after several desorption steps. The biphasic desorption behavior of Zn was characterized by a biphasic desorption model that includes a linear term to represent labile or easily-desorbing fraction and a Langmuirian-type term to represent desorption-resistant fraction. The biphasic desorption model indicated that the size of the maximum capacity of desorption-resistant fraction ($q^{irr}_{max}$) increased with aging in NS. Desorption kinetics and desorption-resistance of Zn in the soils collected from mine tailings (MA, MB and MC collected from surface, subsurface soils and mine waste, respectively) were investigated and compared to the bioavailability to earthworm (Eisenia fetida). Desorption kinetic data of Zn were fitted to several desorption kinetic models. The ratio ($q_{e,d}/q_0$) of remaining Zn at desorption equilibrium ($q_{e,d}$) to initial sorbed concentration ($q_0$) was in the range of 0.53~0.90 in the mine tailings which was higher than that in NS, except MA. The sequential desorption from the mine tailings with 0.01M Na$NO_3$ and 0.01M $CaCl_2$ showed that appreciable amounts of Zn are resistant to desorption due to aging or sequestration. The SM&T (Standard Measurements and Testing Programme of European Union) analysis showed that the sum of oxidizable (Step III) and residual (Step IV) fractions of Zn was linearly related with its desorption-resistance ($q^{irr}_{max}$) determined by the sequential desorption with 0.01M Na$NO_3$ ($R^2$= 0.9998) and 0.01M $CaCl_2$ ($R^2$= 0.8580). The earthworm uptake of Zn and the desorbed amount of Zn ($q_{desorbed}$ = $q_0-q_{e,d}$) in MB soil were also linearly related ($R^2$ = 0.899). Our results implicate that the ecological risk assessment of heavy metals would be possible considering the relation between desorption behaviors and bioavailability to earthworm.

청소년의 인터넷 이용에 미치는 부모의 동기부여 언어 사용의 영향과 목표지향성의 매개 역할

오상화(Sang-Hwa Oh),나은영(Eun-Yeong Na) 한국언론학회 2009 한국언론학보 Vol.53 No.2

경기도 (京畿道) 선사시대 (先史時代) 유적지명표 (遺蹟地名表)

오상화 ( Sang Hwa Oh ) 고려대학교 역사연구소 1961 사총 Vol.6 No.-

어휘 교육 방법 변화의 필요성과 개선방안 연구

오상화 ( Sang Hwa Oh ) 고려대학교 한국어문교육연구소 2014 한국어문교육 Vol.16 No.-

이 연구는 어휘 교육이 단순 단어 교육 및 뜻풀이 교육으로 축소되어 교수되고 있는 현재의 모습에 의문을 품고 진행되었다. 그리고 어휘가 교육적인 관점에서 학습자들에게 좀 더 유의미하게 접근할 수 있어야 한다는 전제 아래 논의를 진행하였다. 이전의 어휘 교육과 현재의 어휘 교육을 토대로 앞으로의 어휘 교육 방법이 변화하여야 함을 밝히기 위하여 어휘 교육이 걸어온 길을 시기와 교육과정으로 구분하여 이들이 어떠한 모습을 하고 있었는지를 살피었다. 그리고 어휘를 어떻게 바라보아야 하는지와 현재의 어휘 교육이 개선되어야 하는 방향을 생각하여 보았다. 어휘 교육은 어휘의 정의에서부터 인식의 변화가 필요하다. 어휘를 ‘단어들의 집합’ 수준으로만 보아서는 안 되며, 어휘 교육의 방향은 학습자의 어휘력 신장을 도모하여 국어 사용 능력의 향상을 꾀하는 방향으로 나아갈 수 있어야 한다. 또한 교수자와 학습자 모두 어휘를 부수적인 것으로 파악하는 도구적 관점에서 벗어나야 한다. 도구적 관점에서 인지적 관점으로 변화할 때에 올바른 어휘 교육과 학습이 이루어질 수 있다. 그리고 이러한 변화의 필요성을 정확히 인식할 때 현재의 어휘 교육 방법이 더 나은 길로 나아갈 수 있다. This study was carried out calling the present form of teaching vocabulary reduced to simple teaching and definition of words into question. Also, a discussion was carried out under a premise that learners should be able to approach vocabulary in a more significant way from an educational viewpoint. To find out that the future teaching vocabulary should change based on previous teaching vocabulary and present teaching vocabulary, the paths that teaching vocabulary followed were divided by period and curriculum to inquire into what they looked like. Also, this study considered how vocabulary should be viewed and the direction in which the present teaching vocabulary should improve. Teaching vocabulary needs changes in perception from the definition of it. Vocabulary should not be viewed just on a level of ‘sets of words,’ and it should be taught in a direction of attempting to promote learners`` vocabulary and improve their ability to use Korean. In addition, both teachers and learners should break away from an instrumental viewpoint of considering vocabulary incidental. Right teaching and learning vocabulary can be achieved only if they are changed from an instrumental viewpoint to cognitive one. Also, correct awareness of this need for change can lead the present method of teaching vocabulary to a better way.

Modified Two-Compartment First-Order Kinetic Model (MTCFOKM)을 이용한 퇴적물에 대한 Ibuprofen의 빠른 및 느린 수착의 동력학 해석

오상화 ( Sang Hwa Oh ) 한국수처리학회 2015 한국수처리학회지 Vol.23 No.5

Ibuprofen is a nonsteroideal anti-inflammatory drug (NSAID) widely used as a pain reliever and therefore, has been frequently detected in rivers, lakes and even their sediments. However, few data have been available for the fate of ibuprofen in the water/sediment compartment despite its high pKow (=3.5). This study focused on the dynamic sorption of ibuprofen onto sediment at pH 4 and 0 and 30 ppt (part per thousand) of salinity. Experimental data were fitted to several kinetic models such as one-site mass transfer model (OSMTM), pseudo-first order kinetic model (PFOKM), pseudo-second order kinetic model (PSOKM), two compartment first order kinetic model (TCFOKM), and modified two compartment first order kinetic model (MTCFOKM). The MTCFOKM was the best in fitting sorption data (R2 > 0.991 and 0.985 at 0 and 30 ppt salinity, respectively). The MTCFOKM can fit the data into the fast and slow sorption kinetics. The results show that the fast sorption of ibuprofen finished within 1 day, whereas the slow sorption finished between 10 and 100 days. Salinity increases the sorbed amount of ibuprofen (qe) and affects also the finish time for the fast and slow sorption. The increase in salinity decreased the finish time for the fast sorption whereas increased it for the slow sorption.

Framing Genetically Modified (GM) Foods : An analysis of news coverage of how to think about GM foods in South Korea

오상화(Sang Hwa Oh),김세일(Sei Hill Kim),김활빈(Hwal bin Kim),김수연(Soo yun Kim) 한국헬스커뮤니케이션학회 2016 헬스커뮤니케이션연구 Vol.14 No.-

본 연구는 한국 언론이 어떻게 유전자 조작 (GM) 식품을 보도하였는지 프레이밍 이론의 세 가지 차원인 핵심 주제, 이슈 속성, 그리고 기사의 톤을 분석함으로써 살펴보았다. 또한 뉴스가 유전자 조작 식품을 보도하는데 있어 언론사의 정치적 정향성 (예를 들어, 보수 대 진보 이데올로기)과 업무관행 (예를 들어 우화적 프레임 빈번한 사용)이 영향을 미쳤는지도 함께 살펴보았다. 분석결과, 핵심주제의 측면에서는 한국에서 유전자 조작 식품에 관한 기사는 대부분 정책 이슈로 다루어지고 있음을 알 수 있었다. 이슈 속성과 관련해서는 진보 신문들이 유전자 조작식품의 사용을 어떻게 규제할 것인지를 보다 자주 다룬 반면, 보수 신문들은 경제적 전망에 대해 주로 보도한 것으로 나타났다. 또한 보수 신문들은 유전자 조작 식품을 지지하는 이유에 대해 보다 자주 논의한 것으로 나타났다. 이러한 결과들은 언론조직의 정치적 정향성과 같은 프레임 빌딩 요인이 뉴스 미디어의 특정 프레임의 선택적 사용에 영향을 줄 수 있음을 잘 보여준 것이다. 기사의 전반적인 톤은 긍정적이기 보다는 부정적 혹은 중립적인 톤으로 보도되어 온 것으로 나타났다. Analyzing newspaper articles and television news transcripts, this study attempts to understand how the Korean news media have presented GM foods. In particular, the currnet study examined how news media have selected organizing theme, issue attributes, and story tone in presenting the issue. We also explore the notion of frame building, looking at factors that may affect the way news media present GM foods. Findings indicate that GM foods have been presented largely as a policy issue in Korea. Findings also show that liberal newspapers are more likely to talk about how to regulate the use of GM foods, while conservative newspapers are more likely to focus on economic prospects. In addition, it was found that conservative newspapers more frequently mention the reasons to support GM foods. These findings demonstrate that such frame building factors as political views of news organizations (e.g., conservative vs. liberal ideology) can influence the news media(e.g., conservative vs. liberal ideology) can ented largely as a policy issue in Korea. Findings also show that liberal newspapers are more likely to talk about how to regulate thentribute to the literature of framing by applying the three framing demensions originally developed in the United States to the context of South Korea.

국내 담수퇴적물의 CODsed 분석방법 평가: CODMn법과 CODCr법의 신뢰성 및 상관성 비교

최지연 ( Ji Yeon Choi ),오상화 ( Sang Hwa Oh ),박정훈 ( Jeong Hun Park ),황인성 ( In Seong Hwang ),오정은 ( Jeong Eun Oh ),허진 ( Jin Hur ),신현상 ( Hyun Sang Shin ),허인애 ( In Ae Huh ),김영훈 ( Young Hoon Kim ),신원식 ( Won Sik 한국환경과학회 2014 한국환경과학회지 Vol.23 No.2

In Korea, the chemical oxygen demand(COD(sed)) in freshwater sediments has been measured by the potassium permanganate method used for marine sediment because of the absence of authorized analytical method. However, this method has not been fully verified for the freshwater sediment. Therefore, the use or modification of the potassium permanganate method or the development of the new COD(sed) analytical method may be necessary. In this study, two modified COD(sed) analytical methods such as the modified potassium permanganate method for COD(Mn) and the modified closed reflux method using potassium dichromate for COD(Cr) were compared. In the preliminary experiment to estimate the capability of the two oxidants for glucose oxidation, COD(Mn) and COD(Cr) were about 70% and 100% of theoretical oxygen demand(ThOD), respectively, indicating that COD(Cr) was very close to the ThOD. The effective titration ranges in COD(Mn) and COD(Cr) were 3.2 to 7.5 mL and 1.0 to 5.0 mL for glucose, 4.3 to 7.5 mL and 1.4 to 4.3 mL for lake sediment, and 2.5 to 5.8 mL and 3.6 to 4.5 mL for river sediment, respectively, within 10% errors. For estimating COD(sed) recovery(%) in glucose-spiked sediment after aging for 1 day, the mass balances of the COD(Mn) and COD(Cr) among glucose, sediments and glucose-spiked sediments were compared. The recoveries of COD(Mn) and COD(Cr) were 78% and 78% in glucose-spiked river sediments, 91% and 86% in glucose-spiked lake sediments, 97% and 104% in glucose-spiked sand, and 134% and 107% in glucose-spiked clay, respectively. In conclusion, both methods have high confidence levels in terms of analytical methodology but show significant different COD(sed) concentrations due to difference in the oxidation powers of the oxidants.

다매체 환경에서 청소년의 미디어 활용 방식에 대한 FGI 연구 : 성별과 환경적 요인에 따른 차이를 중심으로

송요셉(Yosep Song),오상화(Sang-Hwa Oh),김은미(Eun-mee Kim),나은영(Eun-yeong Na),정하소(Haso Jung),박소라(Sora Park) 서울대학교 언론정보연구소 2009 언론정보연구 Vol.46 No.2

변화하는 미디어 환경 속에서 청소년 집단의 미디어 이용 행태를 재검토해보려는 것이 이 연구의 목적이다. 미디어 이용 전반, 광범위하게는 디지털 격차와 관련된 기존의 논의들은 미디어 이용에서의 차이를 발생시키는 주요 요인으로 성별, 세대, 소득, 라이프스타일 등 인구사회학적 배경들을 제시하고 있다. 하지만 이 연구는 기존의 미디어 이용 행태 측정 방법으로는 새로운 미디어 이용 패턴을 간과할 수도 있다는 문제의식을 갖고 있다. 디지털 미디어는 기존의 매스 미디어 이용 패턴과는 다소 다른 방식으로 소비되고 있다. 이 연구에서는 서베이와 같은 구조화된 조사에서는 놓칠 수 있는 이러한 새로운 면모들을 밝히기 위해 FGI를 도입하여 청소년 집단의 미디어 이용 행태를 분석하였다. 이 연구는 47명의 10대 청소년을 대상으로 FGI를 실시하여 미디어의 다중적 이용 방식에 대하여 탐색하고, 미디어 이용과 이들이 맺는 사회적 관계, 그리고 전통적 미디어 환경에서의 성별 차이가 어떻게 다르게 나타나고 있는지를 분석하고자 하였다. 이 연구를 통하여 기존의 이용 패턴을 측정하는 도구들로는 측정되기 어려운 새로운 유형들이 발견되었다. 그런데 이러한 새로운 이용 패턴이 다분히 기존의 성별 차이나 환경적 차이에서 비롯되고 있다는 점에 주목해야할 것이다. This study attempts to examine the changes in the media use patterns of adolescents in the changing media environment. Previous studies on media users show that gender, age, income and life styles are best predictors of media use patterns. However, this study tries to look at the changes in the influence of these factors. In the digital environment it is impossible to have a full view of the actual usage with the existing methods of measurement. This is because people use the digital media in a very distinctive way. So we adopted a qualitative method in order to fully understand the media use behavior of adolescents. FGI of 47 middle school students in the Seoul area, we found that the gender differences were not as obvious in the sense that most girls and boys use similar media content. However, in the way of usage, boys tend to be more addictive, while girls used a more diverse range of media. Boys did not show differences according to income, whereas girls behavior surrounding the media were difference among different social class. Media was a more important activity to girls, while for boys it was just one of many activities that could be shared with friends.

혐기조와 무산소조의 유입수 분할주입에 의한 영양염류 제거

김홍태 ( Hong Tae Kim ),김경호 ( Kyeong Ho Kim ),오상화 ( Sang Hwa Oh ) 한국수처리학회 2004 한국수처리학회지 Vol.12 No.4

N/A This study was carried out to investigate the influence of nitrogen and phosphorus removal with a separate feeding of influent carbon source and also changes of internal recycle to Anoxic tank from final Clarifier in a Parallel Anaerobic-Anoxic tank. The study was operated with 4 phases according to the changes of influent carbon source and internal recycle. The results were concluded as follows, In all phase, Organic and NH^(+)₄-N removal efficiencies were more than 90%. Phase Ⅳ operated with influent COD concentration 290mg/L and internal recycle 30 obtained best results that the concentrations of Effluent SP and NO^(-)₃-N were 0.98mg/L and 2.62mg/L, respectively and as internal recycle increases, denitrification amounts in anoxic tank of phase Ⅳ has more than doubled in denitrification amounts in anoxic tank of phase Ⅰ.