Korean EFL Learners’ Object-drop and Topic-prominence

Saehee Hwang(황세희) 한국영어학회 2015 영어학 Vol.15 No.2

Null Arguments in a Korean EFL Student’s Interlanguage: A Case Study

Saehee Hwang 서울대학교 2012 외국어교육연구 Vol.15 No.-

This paper investigates how an intermediate Korean learner of English uses overt and null pronouns in writing short essays and also whether topic-prominent properties of the first language transfer to and affect the interlanguage. The results of this case study show that this learner was able to provide overt subjects and objects with relative ease, which is consistent with the previous study by Hwang (2005), but that he is somehow still under the influence of the L1 topic-prominent features. The unlearning of topic-prominence seems to be a lengthy process, during which L2 learners utilize some strategies based on surface form in order to avoid producing ungrammatical sentences.

Effects of Construction Grammar-based Instruction on Unlearning Topic-prominence of Korean EFL Learners’ Interlanguage

Saehee Hwang 한국영어학회 2019 영어학 Vol.19 No.3

Physical and Chemical Constraints on Transformation and Mass-increase of Fine Aerosols in Northeast Asia

Saehee Lim,Meehye Lee,PaoloLaj,Sang-Woo Kim,Kang-Ho Ahn,Junsoo Gil,Xiaona Shanga,Marco Zanatta,Kyeong-Sik Kang 한국대기환경학회 2021 한국대기환경학회 학술대회논문집 Vol.2021 No.10

Over the past few decades, northeast Asia has suffered from the extreme levels of PM2.5. Despite extensive efforts and the scientific advances in understanding PM2.5 pollution, the fundamental mechanisms responsible for the occurrence of high PM2.5 concentrations have not been comprehensively understood. In this study, we investigated the physical and chemical drivers for the formation and transformation of atmospheric particles using a four-year dataset of nanoparticle number size distributions, PM2.5 chemical composition, gaseous precursors, and meteorological variables in nor theast Asia outflows. The empirical orthogonal function (EOF) analyses of size-separated particle numbers extracted two modes representing a burst of nanoparticles (EOF1) and an increase in PM2.5 mass (EOF2) associated with persistent anticyclone and synoptic-scale stagnation, respectively. The vertical structure of the particles demonstrated that the synoptic conditions also affected the daily evolution of boundary layer, promoting either the formation of nanoparticles through deep mixing or conversion into accumulation-mode particles in shallow mixed layers. In the haze-development episode equivalent to EOF2 during the KORUS-AQ (KORea-US Air Quality) campaign, the PM2.5 mass reached 63 mg m<SUP>-3</SUP> with the highest contribution from inorganic constituents, which was accompanied by a thick coating of refractory black carbon (rBC) that linearly increased with condensation-mode particles. This observational evidence suggests that the thick coating of rBC resulted from an active conversion of condensable gases into particle-phase on the BC surface, thereby increasing the mass of the accumulation-mode aerosol. Consequently, this result complies with the strategy to reduce black carbon as a way to effectively mitigate haze pollution as well as climate change in northeast Asia.

Valorization of Bacterial Cellulose Produced from Crude Glycerol by Application of Energy Storage Materials

Saehee LEE,Amith ABRAHAM,Alan CHRISTIAN S. LIM,Okkyoung CHOI,Jeong Gil SEO,Byoung-In SANG 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10

Bacterial nanocellulose (BNC), a value-added biomaterial, has attracted attentions as an ideal precursor for nanostructured energy storage materials due to its fascinating features such as high purity, high crystallinity, and mechanical properties. However, the cost of BNC production is a challenge for its industrial applications. The present study used crude glycerol from the biodiesel industry as a carbon source for BNC production with Komagataeibacter sucrofermentans, and higher BNC production was observed in crude glycerol medium than glucose and pure glycerol media. BNC from crude glycerol medium showed a density of 0.92 g cm<SUP>-3</SUP> and a porosity of 38.6% as well as high crystallinity index (85%) and tensile strength (110 ㎫). The derived carbon materials by carbonization of BNC demonstrated highly porous structures and were evaluated for the supercapacitor application. This study showed the valorization of waste resources from the biodiesel industry to bio-nanomaterial and the potential of derived carbon as electrode materials for energy storage applications.

일부지역 치위생(학)과 학생의 영어 관심도와 불안도에 대한 인식

천세희 ( Saehee Cheon ),최규일 ( Gyu Yil Choi ) 한국치위생학회(구 한국치위생교육학회) 2014 한국치위생학회지 Vol.14 No.5

Objectives : The purpose of the study is to investigate the influencing factors on English interest and anxiety in dental hygiene students. Methods : A self-reported questionnaire was filled out by 1,040 dental hygiene students in six universities in Busan and Gyeongnam from April 1 to 30, 2013. The questionnaire consisted of general characteristics, foreign language performance anxiety scale, and English interest. The data were analyzed using descriptive statistics, independent t-tests, one-way ANOVA, and multiple regressions. Results : Those who travelled abroad tended to have a liking for English. English credits significantly influenced on English interest. and employment. The period of English study was proportional to interest and grade of English. Conclusions : The interest and anxiety for English was the major factor to improve the mastery of English. The dental hygienists must try to improve the mastery of language proficiency.

빙하 코어로 복원한 20세기 유럽 대기 중 블랙카본 농도 변화의 추세

임세희(Saehee Lim),Xavier Fain,Patrick Ginot,Vladimir Mikhalenko,Suzanne Preunkert,Paolo Laj 대한지질학회 2015 대한지질학회 학술대회 Vol.2015 No.10

Black carbon variability since preindustrial times in the eastern part of Europe reconstructed from Mt. Elbrus, Caucasus, ice cores

Lim, Saehee,Faï,n, Xavier,Ginot, Patrick,Mikhalenko, Vladimir,Kutuzov, Stanislav,Paris, Jean-Daniel,Kozachek, Anna,Laj, Paolo Copernicus GmbH 2017 Atmospheric Chemistry and Physics Vol.17 No.5

<P>Abstract. Black carbon (BC), emitted by fossil fuel combustion and biomass burning, is the second largest man-made contributor to global warming after carbon dioxide (Bond et al., 2013). However, limited information exists on its past emissions and atmospheric variability. In this study, we present the first high-resolution record of refractory BC (rBC, including mass concentration and size) reconstructed from ice cores drilled at a high-altitude eastern European site in Mt. Elbrus (ELB), Caucasus (5115 m a.s.l.). The ELB ice core record, covering the period 1825-2013, reflects the atmospheric load of rBC particles at the ELB site transported from the European continent with a larger rBC input from sources located in the eastern part of Europe. In the first half of the 20th century, European anthropogenic emissions resulted in a 1.5-fold increase in the ice core rBC mass concentrations with respect to its level in the preindustrial era (before 1850). The summer (winter) rBC mass concentrations increased 5-fold (3.3-fold) in 1960-1980, followed by a decrease until ∼ 2000. Over the last decade, the rBC signal for summertime slightly increased. We have compared the signal with the atmospheric BC load simulated using past BC emissions (ACCMIP and MACCity inventories) and taken into account the contribution of different geographical regions to rBC distribution and deposition at the ELB site. Interestingly, the observed rBC variability in the ELB ice core record since the 1960s is not in perfect agreement with the simulated atmospheric BC load. Similar features between the ice core rBC record and the best scenarios for the atmospheric BC load support anthropogenic BC increase in the 20th century being reflected in the ELB ice core record. However, the peak in BC mass concentration observed in ∼ 1970 in the ice core is estimated to occur a decade later from past inventories. BC emission inventories for the period 1960s-1970s may be underestimating European anthropogenic emissions. Furthermore, for summertime snow layers of the 2000s, the slightly increasing trend of rBC deposition likely reflects recent changes in anthropogenic and biomass burning BC emissions in the eastern part of Europe. Our study highlights that the past changes in BC emissions of eastern Europe need to be considered in assessing ongoing air quality regulation. </P>

Chemical characteristics of submicron aerosols observed at the King Sejong Station in the northern Antarctic Peninsula from fall to spring

Lim, Saehee,Lee, Meehye,Rhee, Tae Siek Elsevier 2019 Science of the Total Environment Vol.668 No.-

<P><B>Abstract</B></P> <P>The water-soluble ions and carbonaceous compounds of PM<SUB>1</SUB> were measured at the King Sejong Station (KSG) in the northern part of Antarctic Peninsula from March to November in 2009. As the sum of all measured species including organic matter [OM; organic carbon (OC)*1.9], the PM<SUB>1</SUB> mass reached a maximum of 936 ng m<SUP>−3</SUP> with the mean of 686 ± 226 ng m<SUP>−3</SUP>. The most abundant constituents were OM (389 ± 109 ng m<SUP>−3</SUP>) and sea-salts (Na<SUP>+</SUP> and Cl<SUP>−</SUP>, 193 ± 122 ng m<SUP>−3</SUP>), which comprised 85% of the PM<SUB>1</SUB> mass. In contrast, the contribution of SO<SUB>4</SUB> <SUP>2−</SUP> was below 1% and its depletion relative to Na<SUP>+</SUP> was prevalent particularly during winter, which was attributed to the frost flowers on newly formed sea-ice surface. The OC concentration was the highest in fall and its subcomponents OC2 and OC3 were moderately correlated with sea-salts (<I>r</I> = 0.5), indicating the marine biogenic source for OC. The elemental carbon (EC) concentration was much lower than OC, leading to the mean OC/EC ratio over 10. While the charred fraction of EC (EC1) was elevated by the long-range transport of biomass burning plume from nearby continent, the mass fraction of soot-EC (EC23) was increased concurrently with enhanced NO<SUB>3</SUB> <SUP>−</SUP>, suggesting EC23 as a good indicator for local influence in pristine environments like Antarctic region.</P> <P><B>Highlights</B></P> <P> <UL> <LI> OM and sea-salts comprised 85% of the PM<SUB>1</SUB> (686 ± 226 ng m<SUP>−3</SUP>) at the KSG. </LI> <LI> The OC/EC ratio was greater than 10 with biogenic source for OC from the ocean. </LI> <LI> Char-EC was enhanced in biomass burning-impacted air from nearby continent. </LI> <LI> Soot-EC is a good tracer indicating local influence in Antarctic environment. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Source signatures from combined isotopic analyses of PM_2.5 carbonaceous and nitrogen aerosols at the peri-urban Taehwa Research Forest, South Korea in summer and fall

Lim, Saehee,Lee, Meehye,Czimczik, Claudia I.,Joo, Taekyu,Holden, Sandra,Mouteva, Gergana,Santos, Guaciara M.,Xu, Xiaomei,Walker, Jennifer,Kim, Saewung,Kim, Hyun Seok,Kim, Soyoung,Lee, Sanguk Elsevier 2019 Science of the Total Environment Vol.655 No.-

<P><B>Abstract</B></P> <P>Isotopes are essential tools to apportion major sources of aerosols. We measured the radiocarbon, stable carbon, and stable nitrogen isotopic composition of PM<SUB>2.5</SUB> at Taehwa Research Forest (TRF) near Seoul Metropolitan Area (SMA) during August–October 2014. PM<SUB>2.5</SUB>, TC, and TN concentrations were 19.4 ± 10.1 μg m<SUP>−3</SUP>, 2.6 ± 0.8 μg C m<SUP>−3</SUP>, and 1.4 ± 1.4 μg N m<SUP>−3</SUP>, respectively. The δ<SUP>13</SUP>C of TC and the δ<SUP>15</SUP>N of TN were − 25.4 ± 0.7‰ and 14.6 ± 3.8‰, respectively. EC was dominated by fossil-fuel sources with F<SUB>ff</SUB> (EC) of 78 ± 7%. In contrast, contemporary sources were dominant for TC with F<SUB>c</SUB> (TC) of 76 ± 7%, revealing the significant contribution of contemporary sources to OC during the growing season. The isotopic signature carries more detailed information on sources depending on air mass trajectories. The urban influence was dominant under stagnant condition, which was in reasonable agreement with the estimated δ<SUP>15</SUP>N of NH<SUB>4</SUB> <SUP>+</SUP>. The low δ<SUP>15</SUP>N (7.0 ± 0.2‰) with high TN concentration was apparent in air masses from Shandong province, indicating fossil fuel combustion as major emission source. In contrast, the high δ<SUP>15</SUP>N (16.1 ± 3.2‰) with enhanced TC/TN ratio reveals the impact of biomass burning in the air transported from the far eastern border region of China and Russia. Our findings highlight that the multi-isotopic composition is a useful tool to identify emission sources and to trace regional sources of carbonaceous and nitrogen aerosols.</P> <P><B>Highlights</B></P> <P> <UL> <LI> For PM<SUB>2.5</SUB>, the average δ<SUP>13</SUP>C of TC and δ<SUP>15</SUP>N of TN were −25.4 ± 0.7‰ and 14.6 ± 3.8‰respectively. </LI> <LI> EC and TC were dominated by fossil-fuel (78 ± 7%) and contemporary (76 ± 7%) sources, respectively. </LI> <LI> Low δ<SUP>15</SUP>N (7.0 ± 0.2‰) with high TN concentration was evident in air masses from Shandong province. </LI> <LI> Multi-isotopic composition is useful to trace regional sources of PM<SUB>2.5</SUB> aerosol. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>δ<SUP>13</SUP>C of TC versus f<SUB>M</SUB> (EC) for different levels of δ<SUP>15</SUP>N of TN observed at Taehwa Research Forest (TRF) and Gosan Climate Observatory (GCO). TRF samples were classified into groups according to air mass origin.</P> <P>[DISPLAY OMISSION]</P>