• 에너지공학
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• 제28권1호
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• pp.1-9
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• 2019

석탄 화력발전소의 배연탈황공정에서 탈황용 흡수제로 사용하는 석회석을 대상으로 본드의 분쇄일지수(BWI) 및 하드그로브지수(HGI) 측정 후 분쇄효율을 비교하였다. 측정결과, 국내 탈황용 석회석의 분쇄성지수는 HGI가 증가함에 따라 BWI가 감소하는 선형적인 반비례 관계를 확인할 수 있었으며, 석회석의 화학조성 및 채광위치에 따른 결정구조에 따라 분쇄효율의 차이가 발생하였다. 이에 따라, 석회석의 분쇄성을 측정할 경우 측정방법이 까다롭고 시간이 오래 걸리는 BWI 보다 간편하게 측정할 수 있는 HGI를 활용하여도 시료의 분쇄성 차이를 확인할 수 있을 것으로 사료되며, 분쇄 특성에 따른 석회석의 선택적 활용 시 탈황효율 또한 향상시킬 수 있을 것으로 판단된다.

• 한국건축시공학회지
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• 제19권2호
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• pp.139-147
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• 2019

본 연구는 최근 방사능 물질의 위험성에 대한 관심이 커지며 원전사고 등의 대규모 인명 피해와 위험지역 선정 등의 이유로 인체의 방사능 안전성에 대한 관심이 커지면서 요구되는 실내 건축용 마감재에 대한 것이다. 일상에서 방사능에 노출되는 여러 가능성 중 실내 공기 중 라돈가스에 대한 관심이 커지면서 라돈가스 흡착형 경화체에 대한 기초연구 자료를 제시한다. 본 연구에 흡착재로 활용된 재료는 규조토와 실리카겔로, 천연 흡착재인 규조토와 인공 흡착재인 실리카겔의 기초 성능 및 흡착 성능을 평가하였다. 향후 실내 공기 중 라돈가스 농도 저감에 대한 정밀한 추가 실험에 대한 연구결과가 필요할 것으로 예상되고, 실험결과에 따른 인공 흡착재인 실리카겔의 라돈가스 흡착 가능성을 기대한다.

• Journal of Microbiology and Biotechnology
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• 제31권8호
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• pp.1069-1078
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• 2021

Sevoflurane postconditioning (SPostC) has been proved effective in cardioprotection against myocardial ischemia/reperfusion injury. It was also reported that heat shock protein 70 (HSP70) could be induced by sevoflurane, which played a crucial role in hypoxic/reoxygenation (HR) injury of cardiomyocytes. However, the mechanism by which sevoflurane protects cardiomyocytes via HSP70 is still not understood. Here, we aimed to investigate the related mechanisms of SPostC inducing HSP70 expression to reduce the HR injury of cardiomyocytes. After the HR cardiomyocytes model was established, the cells transfected with siRNA for HSP70 (siHSP70) or not were treated with sevoflurane during reoxygenation. The lactate dehydrogenase (LDH) level was detected by colorimetry while cell viability and apoptosis were detected by MTT and flow cytometry. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting were used to detect HSP70, apoptosis-, cell cycle-associated factors, iNOS, and Cox-2 expressions. Enzyme-linked immuno sorbent assay (ELISA) was used to measure malondialdehyde (MDA) and superoxide dismutase (SOD). SPostC decreased apoptosis, cell injury, oxidative stress and inflammation and increased viability of HR-induced cardiomyocytes. In addition, SPostC downregulated Bax and cleaved caspase-3 levels, while SPostC upregulated Bcl-2, CDK-4, Cyclin D1, and HSP70 levels. SiHSP70 had the opposite effect that SPostC had on HR-induced cardiomyocytes. Moreover, siHSP70 further reversed the effect of SPostC on apoptosis, cell injury, oxidative stress, inflammation, viability and the expressions of HSP70, apoptosis-, and cell cycle-associated factors in HR-induced cardiomyocytes. In conclusion, this study demonstrates that SPostC can reduce the HR injury of cardiomyocytes by inducing HSP70 expression.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권1호
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• pp.17-24
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• 2022

This work examined the effect of mixing transition metal-based additives [FeCl₃, Fe-containing paper mill sludge (PMS), CoCl₂·H₂O, ZrO₂, and α-Fe₂O₃] on the thermochemical conversion of coffee waste (CW) in carbon dioxide-assisted pyrolysis process. Compared to the generation amounts of syngas (0.7 mole% H₂ & 3.0 mole% CO) at 700℃ from single pyrolysis of CW, co-pyrolysis in the presence of Fe- or Zr-based additives resulted in the enhanced production of syngas, with the measured concentrations of H₂ and CO ranging 1.1-3.4 mole% and 4.6-13.2 mole% at the same temperature, respectively. In addition, α-Fe₂O₃ biochar possessed the adsorption capacity of As(V) (19.3 mg g^-1) comparable to that of ZrO₂-biochar (21.2 mg g^-1). In conclusion, solid-type Fe-based additive can be highly considered as an efficient catalyst to simultaneously produce syngas (H₂ & CO) as fuel energy resource and metal-biochar as sorbent.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권6호
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• pp.47-57
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• 2022

A number of different methods have been used for modeling the sorption of volatile organic chlorinated compounds such as tetrachloroethylene/perchloroethylene (PCE). In this study, PCE was adsorbed in several natural sorbents, i.e., Pahokee peat, vermicompost, BionSoil^®, and natural soil, in the batch experiments. Several sorption models such as linear, Freundlich, solubility-normalized Freundlich model, and Polanyi-Manes model (PMM) were used to analyze sorption isotherms. The relationship between sorption model parameters, organic carbon content (f_oc), and elemental C/N ratio was studied. The organic carbon normalized partition coefficient values (log K_oc = 1.50-3.13) in four different sorbents were less than the logarithm of the octanol-water partition coefficient (log K_ow = 3.40) of PCE due to high organic carbon contents. The log K_oc decreased linearly with log f_oc and log C/N ratio, but increased linearly with log O/C, log H/C, and log (N+O)/C ratio. Both log K_F,oc or log K_F,oc decreased linearly with log f_oc (R² = 0.88-0.92) and log C/N ratio (R² = 0.57-0.76), but increased linearly with log (N+O)/C (R² = 0.93-0.95). The log q_max,oc decreased linearly as log f_oc and log C/N increased, whereas it increased with log O/C, log H/C and log (N+O)/C ratios. The log q_max,oc increased linearly with (N+O)/C indicating a strong dependence of q_max,oc on the polarity index. The results showed that PCE sorption behaviors were strongly correlated with the physicochemical properties of soil organic matter (SOM).

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4013-4021
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• 2022

A kind of zirconium phosphate mesoporous coordination polymer Zr-EDTMPA was successfully synthesized and characterized using XRD, FTIR, TGA, EA, SEM-EDS, and N₂ sorption-desorption measurements. The prepared Zr-EDTMPA was first employed for the removal of Co(II) from an aqueous solution, and the effects of pH, contact time, temperature, initial Co(II) concentration, reusability, and sorption mechanism were systematically investigated. The results showed that the Zr-EDTMPA is a zirconium phosphate complex formed by the coordination of EDTMPA to Zr in a molar ratio of 1:1. The sorption of Co(II) by Zr-EDTMPA was a pH-dependent, spontaneous and endothermic process, which was better fitted to the pseudo-second-order kinetic model and Langmuir isotherm model. The Zr-EDTMPA was demonstrated to have excellent reusability and presented a high sorption capacity of 73.0 mg·g^-1 for Co(II) at pH 8.0. The sorption mechanism was mainly attributed to the strong coordination between cobalt and the untapped hydroxyl functional groups on Zr-EDTMPA, which was confirmed by XPS spectra. Therefore, as a candidate sorbent with high sorption capacity and excellent reusability, Zr-EDTMPA has a great potential for the removal of Co(II) from aqueous solutions.

• Korean Chemical Engineering Research
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• 제61권4호
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• pp.619-626
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• 2023

건식 이산화탄소 분리공정에서 아민 구조체의 운전 특성을 규명하기 위하여 1차 아민과 2차 아민 구조체를 합성하였다. TSA 조건에서 1차 아민과 2차 아민 건식 포집 분리제의 분리 특성을 연구하였다. (3-Aminopropyl) triethoxysilane을 1차 아민 전구체로 가교제로 이용하여 가교 결합된 2차 아민 전구체를 합성하였다. 합성된 2차 아민 전구체를 Tetraethyl orthosilicate를 구조배양제로 사용하여 2차 아민 고체상 이산화탄소 분리제를 합성하였다. 1차 및 2차 아민 구조체의 TSA 공정조건에서 이산화탄소 분리 특성을 비교하였다. 1차 아민에 흡수된 이산화탄소 분리는 170 ℃ 이상에서 완전히 이루어지나 이산화탄소에 의하여 아민이 우레아로 전환되며, 아민기 손실이 발생되었다. 아민 손실이 낮은 130 ℃ 재생시 1차 아민 분리제의 공정 운전성능(working capacity)은 본 구조체의 경우 2% 이하로 나타났다. 2차 아민이 낮은 재생온도에서 높은 이산화탄소 분리능을 나타내었다. 이산화탄소 2% 흡수 분위기와 100% 재생분위기에서 약 6.5%의 공정 운전 성능을 예측할 수 있었다.

• 식물병연구
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• 제30권2호
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• pp.157-164
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• 2024

Jack bean (Canavalia ensiformis) is one of healthy products for fermented or functional food in Korea and is widely distributed and cultivated worldwide. During August 2022, Jack bean plants showing symptoms of yellow flecks, chlorosis, necrotic spots and mosaic were observed in Jangheung-gun, South Korea. By transmission electron microscopy, flexuous filamentous virus particles of approximately 750×13 nm in size were observed in the symptomatic leaf samples. The infection of a Korean isolate of clover yellow vein virus (ClYVV-Ce-JH) was confirmed using double antibody sandwich enzyme-linked sorbent assay, reverse transcription polymerase chain reaction and high-throughput sequencing. The complete genome sequence of ClYVV-Ce-JH consists of 9,549 nucleotides (nt) excluding the poly (A) tail and encodes 3,072 amino acids (aa), with an AUG start and UAG stop codon, containing one open reading frame that is typical of a potyvirus polyprotein. The polyprotein of ClYVV-Ce-JH was divided into ten proteins and each protein's cleavage sites were determined. The coat protein (CP) and polyprotein of ClYVV-Ce-JH were compared at the nt and aa levels with those of the previously reported 14 ClYVV isolates. ClYVV-Ce-JH shared 92.62% to 99.63% and 93.39% to 98.05% at the CP and polyprotein homology. To our knowledge, this is the first report of a Korean isolate of ClYVV from Jack bean plants and the complete genome sequence of a ClYVV Jack bean isolate in the world.

• 대기
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• 제34권2호
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• pp.187-202
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• 2024

We analyzed the observed characteristics of monoterpene and developed an empirical formula for monoterpene concentration in the pine-dominated mixed forest of the National Center for Forest Therapy. Monoterpene was measured at 0800, 1200 and 1700 LST once a month using sorbent tube sampling coupled with thermal desorption gas chromatography and mass spectrometry. Monoterpene concentration is low in winter and shows a maximum in June and July. The major components of monoterpene are alpha-pinene, camphene and beta-pinene. During the warm period from May to November, monoterpene concentration is higher at 0800 and 1700 LST than at 1200 LST. The empirical formula takes into account the vegetation variables, temperature-controlled emission, oxidation processes and dilution by wind. The vegetation variable accounts for the difference in observed monoterpene concentration between two sites. The observed monoterpene concentration normalized by the vegetation variable increases exponentially with air temperature. The oxidation process explains the lower monoterpene concentration at 1200 LST than at 0800 and 1700 LST during the warm period. The monoterpene estimates using the empirical formula shows a correlation of 0.52 with the observation for the development period (2018~2020), while it shows a correlation of 0.72 for the validation year (2021). Such higher correlation for the validation year than for the development period is due to the fact that variability of monoterpene concentration is better explained by air temperature in 2021 than in the development period. However, the developed formula underestimates the monoterpene concentration in May and June, showing the limitation in accurately capturing the monthly variation of monoterpene.

• Korean Chemical Engineering Research
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• 제55권3호
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• pp.419-425
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• 2017

본 연구에서는 벤치급 건식 $CO_2$ 포집 성능평가 장치에서 흡수반응기 내부의 구조와 형태에 따른 K-계열 흡수제(KEP-CO2P2, 한국전력공사 전력연구원)의 성능특성을 확인하였다. 흡수반응기 혼합영역(mixing-zone)에 구조와 형태가 다르게 제작된 두 종류의 열교환기가 적용되었으며, 각각 CASE 1과 CASE 2로 나뉘어 동일한 조업조건으로 연속운전을 수행하였다. 연속운전동안 흡수반응 온도는 $75{\sim}80^{\circ}C$, 재생반응 온도는 $190{\sim}200^{\circ}C$, 그리고 반응기체($CO_2$) 농도는 12~14 vol%으로 설정하였다. 특히 흡수제의 흡수능 비교를 위해 흡수반응기 혼합영역의 차압을 400~500 mm$H_2O$로 유지하며 운전하였다. 또한 반응 후 채집한 시료는 반응성 비교를 위해 TGA를 이용하여 물성분석을 하였다. CASE 1 실험에서 $CO_2$ 제거효율과 동적흡수능은 각각 64.3%, 2.40 wt%으로 산출 되었고, CASE 2 실험에서 $CO_2$ 제거효율과 동적흡수능은 각각 81.0%, 4.66 wt%으로 산출되었다. 또한 반응 후 흡수제에 대한 TGA 측정 결과의 무게감량을 이용하여 흡수제의 동적흡수능을 계산한 결과, CASE 1과 CASE 2 실험에서 반응 후 흡수제의 동적흡수능은 각각 2.51 wt%와 4.89 wt%으로 산출되었다. 결론적으로 동일한 조업조건에서 흡수반응기 내부에 삽입되는 열교환기의 구조와 형태에 따라 흡수제의 성능 차이가 있는 것을 확인하였다.