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섬유 및 혼화제를 이용한 황토 모르타르의 수축균열 제어
문주현(Mun Ju-Hyun),양근혁(Yang Keun-Hyeok),전중규(Jeon Joong-Kyu),황혜주(Hwang Hye-Zoo) 대한건축학회 2012 大韓建築學會論文集 : 構造系 Vol.28 No.8
A total of 8 hwang-toh mortar mixes with no cement were tested to evaluate the effect of different fibers and admixtures on the control of shrinkage cracks of such mortars. The fiber types added were Lyocell, Poly-Amid and PVA, while, CSA and organic polymer were selected as the admixture. The shrinkage crack resistance of hwang-toh mortar were examined from the unrestrained drying shrinkage strain, restrained drying shrinkage and plastic shrinkage. Test results revealed that the unrestrained drying shrinkage strain of hwang-toh mortar sharply increased at an early age showing approximately 2.5 times higher values than predictions obtained from ACI 209, regardless of the addition of fibers and admixtures. In addition, cracks owing to the restrained drying shrinkage developed at the only age of 1.6 days in all test mixes; as a result, the cracking grade of hwang-toh mortar was evaluated to be high. On the other hand, the addition of fibers required a value of fiber spacing above 0.0003 in order to enhance the tensile resistance capacity of hwang-toh mortar under the restrained drying shrinkage and reduce the cracking area under the plastic shrinkage. Overall, it could be concluded that moist curing at an early age and the addition of fiber with fiber spacing above 0.0003 are practically effective in reducing shrinkage crack of hwang-toh mortar.
Toxicological evaluation of organic contaminants in aquatic system using zebrafish embryo
Hwang-Ju Jeon(전황주),Hyeseung Choe,Chaeun Kim,Sung-Eun Lee 한국농약과학회 2021 한국농약과학회 학술발표대회 논문집 Vol.2021 No.11
A threat to living organisms resulting from climate change on this planet leads to growing concern about the environment. One of these parts was Agriculture originated organic pollutants, known as a group of environmental contaminants. These contaminants cause many negative effects and even death on living organisms including aquatic vertebrates. But, many toxicological studies were still focused on their viewpoint only on the death problem. In this phenomenon, we tried to explore the possible toxicological effects of EPN on the early developmental stage of aquatic vertebrates using zebrafish embryos. In the acute toxicity test of AB strain zebrafish embryo, both pericardial and yolk sac edemas were observed at 500 ppb EPN treated group. Moreover, the presence of 250 ppb EPA makes zebrafish embryo obtain hematoma near the heart. To confirm phenotype of zebrafish more clearly, three different transgenic line were used including Tg[fli1a:EGFP], Tg[cmlc2:EGFP], and Tg[gata1:GFP]. In transgenic zebrafish, the malformation of the embryos was still observed. Especially, in the fluorescent image of Tg[cmlc2:EGFP], the formation of the heart seemed to be disturbed seriously. In the real-time qPCR data, the level of the transcripts related to early-stage heart formation, nppa, and myl7, were up and down-regulated to 2.0 and 0.26-fold respectively. In addition, the heart rate of the embryo was decreased at 250 and 500 ppb. Taking all these results together, EPN has the possibility of negative effects on the early-stage development of aquatic vertebrates including hematoma, malformation of the heart, and abnormal development of the internal circulatory system. Therefore, continuous monitoring and proper management are required.
04 포스터 발표 : 환경 화학 분야(PC) ; PC-10 : 농경지 토양 중 PCB의 분포
전황주 ( Hwang Ju Jeon ),구본화 ( Bon Hwa Ku ),남태훈 ( Tae Hun Nam ),김용찬 ( Yong Chan Kim ),이지형 ( Ji Hyoung Lee ),최재일 ( Jae Il Choi ),이성은 ( Sung Eun Lee ) 한국환경농학회 2015 한국환경농학회 학술대회집 Vol.2015 No.-
Polychlorinated biphenyl (PCB) compounds are persistent and hazardous to the environment. They are frequently found in industrial areas because their uses were bound to industrial purposes. However, it has been reported that PCBs can be translocated to agricultural soils via various ways. Therefore, PCBs are also found in agricultural foods including crops. PBCBs are consisted of 209 congeners and analyzed by GC-ECD, GC-MS and HRGC-HRMS. In this study, 27 PCB congeners were used to monitor PCBs in agricultural soil samples collected in Chungcheong and Gyeonggi Provinces. Prior to analyze soil samples, method validations were undertaken to know precision, accuracy, and recovery using #209 PCB congener (DeCB1, decachlorobiphenyl) followed by a method certified Environment Protection Agency. Those validation results were acceptable and all procedures containing soxhlet extractions and column chromatography for clean-up were adopted for analysis. All soil samples were analyzed for their basic properties including soil organic contents and soil pH. All soil samples were undertaken by soxhlet extraction for 16 h. Silicagel column chromatography was employed to clean up the samples and the final eluate was evaporated and then redissolved in toluene after complete dryness. The samples were analyzed using GC-ECD. Some of PCB congeners were found in these analyses and finally needs to be confirmed by GC-Ms and HRGC-HRMS.
5-Benzyloxymethyl-3-(thiophen-5-yl)-1,2-isoxazoline 유도체의 합성과 제초활성
전동주(Dong Ju Jeon),송종환(Jong Hwan Song),김형래(Hyoung Rae Kim),김은주(Eun Ju Kim),황인택(In Taek Hwang) 한국농약과학회 2007 농약과학회지 Vol.11 No.2
Nobel series of 5-benzyloxymethyl-3-(thiophen-5-yl)-1,2-isoxazoline derivatives were designed and synthesized. The herbicidal activities of these compounds to main dominant weeds to these compounds were evaluated in pot tests that simulated rice paddy conditions. Most of the compounds showed high herbicidal activity to main dominant weeds occurring in rice field without the serious rice injury.
Jeon, Hee-Jae,Ju, Kang-Sig,Joo, Jai-Hwang,Kim, Hyun-Gyun The Korean Institute of Electrical and Electronic 2012 Transactions on Electrical and Electronic Material Vol.13 No.1
LED lighting systems that combine lighting capability, emotional and physiological characteristics are required for lighting source and multifunctional applications. In this work, Simulation studies using optical analysis software packages, Light Tools, are presented. This is done to estimate the uniformity ratio of illuminance and photosynthetic photon flux density (PPFD) of the periodic 2D lattice arrangements, such as square, diamond, two-way bias quadrangular, hexagonal, and Kagome lattices, under the same transmissivity, absorptance and reflectivity. It has been found out that the two-dimensional Kagome lattice arrangement exhibited high uniformity ratio of illuminance and PPFD compared to other lattices. Accordingly, these results can be used to guide a design and improve the lighting environment which in turn would maximize the uniform distributions of illuminance.
Jeon, Sehyun,Hwang, Seok‐,Il,Son, Young Don,Kim, Young‐,Bo,Lee, Yu Jin,Kim, Seog Ju FOLIA PUBLISHING SOCIETY 2019 PSYCHIATRY AND CLINICAL NEUROSCIENCES Vol.73 No.6
<P><B>Aim</B></P><P>The aim of this study was to assess neuropsychological correlations with the T2* relaxation time (T2*‐RT) of hippocampal subregions in adolescents using ultra‐high‐field (UHF) 7.0‐T magnetic resonance imaging (MRI).</P><P><B>Methods</B></P><P>We assessed the T2*‐RT of hippocampal subregions in 31 healthy 11th‐ or 12th‐grade high school students using an UHF 7.0‐T MRI system. T2*‐RT of the cornu ammonis (CA) 1, CA2, CA3, and CA4 subregions and the subiculum were calculated for both the left and right hippocampus. Seven subtests of the Cambridge Neuropsychological Test Automated Battery were administered to the subjects to assess visuospatial memory.</P><P><B>Results</B></P><P>Poor performances in delayed recall in the pattern‐recognition test were significantly correlated with longer T2*‐RT in the bilateral subiculum (right, <I>r</I> = −0.480, <I>P</I> = 0.006; left, <I>r</I> = −0.648, <I>P</I> < 0.001) and the left CA2 (<I>r</I> = −0.480, <I>P</I> = 0.006).</P><P><B>Conclusion</B></P><P>This study showed that longer T2*‐RT in the subiculum were associated with poorer performances in delayed recall in the visual memory tasks. This finding suggests that the subiculum might play a predominant role in delayed recall in adolescents.</P>