• 전자공학회논문지
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• 제49권12호
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• pp.179-183
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• 2012

3차원 시뮬레이션을 이용하여 터널링 전계효과 트랜지스터(TFET)의 불순물 분포 변동(RDF) 효과에 대해 살펴보았다. TFET의 RDF 효과는 매우 낮은 바디 도핑 농도 때문에 많이 논의되지 않았다. 하지만 본 논문에서는 임의로 생성되고 분포되는 소스 불순물이 TFET의 문턱전압 ($V_{th}$)과 드레인 유기 전류 증가 (DICE), 문턱전압이하 기울기 (SS)의 변화를 증가시킴을 발견하였다. 또한, TFET의 RDF 효과를 감소시킬 수 있는 몇 가지 방법을 제시하였다.

• 한국환경과학회지
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• 제15권5호
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• pp.447-459
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• 2006

Long-term trends and distribution patterns of water quality were investigated in the Cheonsu Bay of Korea from 1983 to 2004. Water samples were collected at 4 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids (SS), chemical oxygen demand (COD), dissolved oxygen (DO) and nutrients. Spatial distribution patterns were not clear between stations but the seasonal variations were distinctive except COD, SS and nitrate. Twenty two year long-term trend analysis by PCA revealed the significant changes in water quality in the study area. Water quality during 1980's and early 1990's showed high SS, low nutrients and low COD which increased during the mid and late 1990's and early 2000's. Overall water duality in the Cheonsu Bay indicated the increase in nutrients and COD concentration.

• 상하수도학회지
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• 제24권4호
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• pp.407-412
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• 2010

The purpose of this study was to investigate removal efficiencies of contaminants in night soil treatment plant using the B3 system. The samples were collected from retaining tank and settlement tank in Yechon night soil plant. We experimented concentrations of BOD, COD, SS, TN and TP. Concentration data were processed using removal efficiencies by season and correlation analysis with pilot running parameters. Removal efficiencies of total organic carbon was over 96%, TN was 98% during summer, 80.9% during winter. In the case of TP, the highest removal efficiencies was 94.1% during fall and the lowest removal efficiencies was 82% during spring. Results of correlation analysis showed two positive correlation groups and one negative group. Positive correlations were among temperature, BOD and TN. The others were pH, BOD, COD, SS, TN and TP. Negative correlation were among MLSS, BOD, COD, SS, TN, TP.

• 상하수도학회지
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• 제22권3호
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• pp.329-336
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• 2008

The pilot study was conducted to evaluate the applicability of air flotation(AF) processes combined with biological nutrient removal(BNR) for the retrofitting of conventional wastewater treatment facilities. The BNR system was operated in pre-denitrification and intermittent aeration; developed ceramic membrane diffusers were installed to separate the solid-liquid of activated sludge at the bottom of a flotation tank. Before performing a pilot scale study, the size distribution of microbubbles generated by silica or alumina-based ceramic membrane diffusers was tested to identify the ability of solid-liquid separation. According to the experimental results, the separation and thickening efficiency of the alumina-based ceramic membrane diffuser was higher than the silica-based ceramic membrane diffuser. In a $100m^3/d$ pilot plant, thickened and return sludge concentration was measured to be higher than 15,000mg SS/L, therefore, the MLSS in the bioreactor was maintained at over 3,000mg SS/L. The effluent quality of the AF-BNR process was 4.2mg/L, 3.7mg/L, 10.6mg/L and 1.6mg/L for $BOD_5$, SS, T-N and T-P, respectively. Lastly, it was revealed that the unit treatment cost by flotation process is lower than about $1won/m^3$ compared to a gravity sedimentation process.

• BMB Reports
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• 제44권5호
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• pp.341-346
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• 2011

The single-stranded DNA binding activity of the Escherichia coli RecA protein is crucial for homologous recombination to occur. This and other biochemical activities of ssDNA binding proteins may be affected by various factors. In this study, we analyzed the effect of $CaCl_2$, NaCl and $NH_4NO_3$ salts in combination with the pH and nucleotide cofactor effect on the ssDNA-binding activity of RecA. The studies revealed that, in addition to the inhibitory effect, these salts exert also a stimulatory effect on RecA. These effects occur only under very strict conditions, and the presence or absence and the type of nucleotide cofactor play here a major role. It was observed that in contrast to ATP, ATP${\gamma}$S prevented the inhibitory effect of NaCl and $NH_4NO_3$, even at very high salt concentration. These results indicate that ATP${\gamma}$S most likely stabilizes the structure of RecA required for DNA binding, making it resistant to high salt concentrations.

• 한국농공학회지
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• 제41권4호
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• pp.37-46
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• 1999

Field experimnet of constructed wetland for rural wastewater treatment was performed from July 1998 to April 1999 including winter to examine the seasonal effect on the wetland performance. The system worked without freezing even under $-10^{\circ}C$ of air temperature as long as watewater was flowing. BOD removal rates varied in similar pattern as the air temperature, and winter performance was relatively lower than that in the growing season. However, removing performance during winter was still significant, and BOD removal rates were almost the the same as in the growing season. SS removal rate was relativelyless affected by temmperature, but lower decay rate during the winter can result in accumulation of the SS in the system, which releases constituents in the next spring and can affect whole system performance. The winter removal rates of nutrients like T-N and T-P were decreased about half compared to the growing season and low temperature. To maintain stabilized wetland performanced including winter time, supplying minimum heating for plants could be an alternative in field application. Experimental data was compared with NADB(North Americal Wetlands for Water Quality treatment database), and general performance of the system was within the reasonable range. The pollutant loading and effluent concentration of the experimented system were in high margin. Base on the experiment and databases, the required effluent water quality could be achieved if loading rate adjusted as ilulstrated in the database.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1031-1034
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• 2009

Fluorescence of quinolones including norfloxacin, ciprofloxacin and S- and R-ofloxacin is quenched upon association with single and double-stranded DNA (ss- and ds-DNA). The ratios of fluorescence intensity in the presence of DNA to its absent were plotted with respect to the DNA concentration to construct the Stern-Volmer plot. The slope of the Stern-Volmer plot become larger as the temperature is lowered, ensuring that the fluorescence quenching is static process, i.e., the fluorescence is quenched by formation of the non-fluorescent complex between quinolone and DNA. In the static quenching mechanism, the quenching constant which is equivalent to the slope of the Stern-Volmer plot, is considered as the equilibrium constant for the association of quinolones and DNA. From the temperature-dependent equilibrium constant, ${\Delta}H^0\;and\;{\Delta}S^0$ was obtained using the van’t Hoff relation. In general, association of the quinolone with ds- as well as ss-DNA is energetically favorable (an exothermic) process while the entropy change was unfavorable. Due to the steric effect of the substituents, the effect of the quinolone ring is smaller on the ss-DNA compared to ds-DNA.

• 대한설비공학회지:설비저널
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• 제11권4호
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• pp.19-33
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• 1982

우리나라에서 대량으로 제기되는 연탄재는 밀도가 낮으면서도 충분한 강도를 가지며 표면적을 많이 제공할 뿐만 아니라 흡착성이 있으므로 고정미생물막공법에서 매질로 사용하여 유기성 폐수를 처리하면 유기물 제거효율이 매우 높을 뿐만 아니라, 처리수의 BOD농도를 표면부하나 용적부하로 계산할 수 있으므로 처리시설의 설제가 용이한 경제적인 폐수처리공법이 될 수 있다. 그러나 연탄재 매질을 장기간 사용하면 원수내의 SS, 성장한 미생물의 탈리 등에 의하여 처리수의 수질이 악화될 수도 있으므로 종말침전지가 요구될 수도 있다.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4474-4480
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• 2022

Deep geological disposal using a multibarrier system is a promising solution for treating high-level radioactive (HLRW) waste. The HLRW canister represents the first barrier for the migration of radionuclides into the biosphere, therefore, the corrosion behavior of canister materials is of significance. In this study, the electrochemical behaviors of SS316L, Ti-Gr.2, Alloy 22, and Cu in naturally aerated KAERI underground research tunnel (KURT) groundwater solutions were examined. The corrosion potential, current, and impedance spectra of the test materials were recorded using electrochemical methods. According to polarization and impedance measurements, Cu exhibits relatively higher corrosion rates and a lower corrosion resistance ability than those exhibited by the other materials in the given groundwater condition. In the anodic dissolution tests, SS316L exposed to the groundwater solution exhibited the most uniform corrosion, as indicated by its surface roughness. This phenomenon could be attributed to the extremely low concentration of chloride ions in KURT groundwater.

• 상하수도학회지
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• 제28권3호
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• pp.315-324
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• 2014

The residents' odor complaint is steadily increasing by odor causing from sewage system. A current drainage facilities and septic tank are included in the individual sewerage according to Sewerage Act. However, definitions and legal standards of drainage tank are insufficient. In addition, specifications and maintenance standards related to structure and size are not established. In this research, effect of drainage tank in individual sewage facilities on the odor occurrence was studied and the concentrations of $H_2S$ and composite odor were measured. From the measurements, the concentration of $H_2S$ and composite odor were 1 ppm ~ 5 ppm and 1.04 OU ~ 4.05 OU, respectively, before pump operation. Also, the concentration of $H_2S$ and composite odor were 5 ppm ~ 33 ppm and 5.10 OU ~ 35.04 OU, respectively, after pump operation. The concentration of SS in the effluent from drainage tank was ranged from 840 mg/L to 1,980 mg/L. These high concentration of SS seemed to be the major source of foul smell when high concentrated suspended solids in the public sewerage system were decomposed and then emitted. In this research, correlation coefficient ($R^2$) between $H_2S$ and composite odor before and after pumping were 0.925 and 0.918, respectively.