• Title/Summary/Keyword: 동시 환원

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The Context and Reality of Memes as Information Resources: Focused on Analysis of Research Trends in South Korea (정보자원으로서 '밈'의 맥락과 실재 - 국내 연구동향 분석을 중심으로 -)

  • Soram Hong
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.34 no.3
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    • pp.227-253
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    • 2023
  • The study is a preliminary study to conceptualize memes as information resources for literacy education in information environment changed with digital revolution. The study is to explain the context and reality of memes in order to promote the utilization of memes as information resources. The research questions are as follows: First, what topics are 'memes' studied with? Second, what things are captured and studied as 'memes'? The study conducted frequency and co-occurrence network analysis on 145 domestic studies and contents analysis on 73 domestic studies. The results are as follows: First, memes were mainly studied in the fields of 'humanities', 'social sciences', 'interdiciplinary studies', and 'arts and kinesiology'. Studies based on Dawkins' concept of memes (around 2012), studies on introducing the concept of memes to explain the spread of Korean Wave content (around 2015), and independent studies of memes as a major research topic in cultural sociology (around 2019) were performed. Second, memes are linguistic. Language memes (L-memes) are 102 (37%), language-visual memes (LV-memes) are 23 (8%), language-visual-musical memes (LVM-memes) are 21 (8%). Keyword 'language meme' ranked high in frequency, degree centrality and betweenness centrality of co-occurrence network. In other words, memes are expanding as a unique information phenomenon of cultural sociology based on linguistic characteristics. It is necessary to conceptualize meme literacy in terms of information literacy.

Study on the On-Board Test of After-Treatment Systems to Reduce PM-NOx in Low-Speed Marine Diesel Engine (선박용 저속디젤엔진 적용을 위한 PM-NOx 동시저감 배출저감설비 해상실증 연구)

  • Dong-Kyun Ko;Suk-Young Jeong;In-Seob Kim;Gye-Won An;Youn-Woo Nam
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.5
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    • pp.497-504
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    • 2023
  • In this study, Selective catalytic reduction (SCR) + Diesel particulate filter (DPF) system was installed on a ship with a low-speed engine to conduct the on-board test. The target ship (2,881 gross tons, rated power 1,470 kW@240 rpm ×1) is a general cargo ship sailing in the coastal area. Drawing development, approvals and temporary survey of the ship were performed for the installation of the after-treatment system. For performance evaluation, the gaseous emission analyzer was used according to the NOx technical code and ISO-8178 method of measurement. The particulate matter analyzer used a smoke meter to measure black carbon, as discussed by the International Maritime Organization (IMO). Tests were conducted using MGO (0.043%) and LSFO (0.42%) fuels according to the sulfur content. The test conditions were selected by considering the engine rpm (130, 160 and 180). Gaseous emission and particulate matter (smoke) were measured according to the test conditions to confirm the reduction efficiency of the after treatment system. The results of NOx emission and particulate matter (smoke) revealed that reduction efficiency was more than 90%. The exhaust pressure met the allowable back pressure (less than 50 mbar). This study confirms the importance of the on-board test and the potential of SCR + DPF systems as a response technology for reducing nitrogen oxides and particulate matter.

Rhizosphere Enhances Removal of Organic Matter and Nitrogen from River Water in Floodplain Filtration (홍수터 여과를 이용한 하천수의 질소와 유기물 제거에 미치는 근권의 효과)

  • Jeong, Byeong-Ryong;Chung, Jong-Bae;Kim, Seung-Hyun;Lee, Young-Deuk;Cho, Hyun-Jong;Baek, Nam-Joo
    • Korean Journal of Soil Science and Fertilizer
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    • v.36 no.1
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    • pp.8-15
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    • 2003
  • If contaminated river water is sprayed over a floodplain, the microbial processes can simultaneously remove organic matter and nitrogen during the infiltration through the sediment profile. The effect of rhizosphere on the removal of organic matter and nitrogen from contaminated river water was investigated using floodplain lysimeters. River water was sprayed at a rate of $68.0L\;m^{-2}\;d^{-1}$ on the top of the lysimeters with or without weed vegetation on the surface, Concentrations of $NO_3$, $NH_4$ and dissolved oxygen (DO), and chemical oxygen demand (COD) and Eh in water were measured as functions of depth for 4 weeks after the system reached a steady state water flow and biological reactions. A significant reductive-condition for denitrification developed in the 30-cm surface profile of lysimeters with weeds. At a depth of 30 cm, COD and $NO_3$-N concentration decreased to 5.2 and $0.9mg\;L^{-1}$ from the respective influent concentrations of 18.2 and $9.8mg\;L^{-1}$. The removal of $NO_3$ in lysimeters with weeds was significantly higher than in those without weeds. Vegetation on the top was assumed to remove $NO_3$ directly by absorption and to create more favorable conditions for denitrification by supply of organic matter and rapid $O_2$ consumption, In the lysimeters without weeds, further removal of $NO_3$ was limited by the lack of an electron donor, i.e. organic matter. These results suggest that the filtration through native floodplains, which include rhizospheres of vegetation on the surface, can be effective for the treatment of contaminated river water.

Environmental Impact Assessment by Marine Cage Fish Farms: II. Estimation of Hydrogen Sulfide Oxidation Rate at $O_2$-H$_2$S Interface and Sulfate Reduction Rate in Anoxic Sediment Layer (해상 어류가두리양식장의 환경영향 평가: II. 가두리 양식장 퇴적물의 산소-황화수소 경계면에서 황화수소의 산화율 및 무산소 퇴적층에서 황산염 환원율 추정)

  • Lee, Jae-Seong;Kim, Kee-Hyun;Yu, Jun;Lee, Pil-Yong;Jung, Rae-Hong;Lee, Wong-Chan;Han, Jung-Jee;Lee, Yong-Hwa
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.9 no.2
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    • pp.64-72
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    • 2004
  • We measured the vertical profiles of $O_2$, H$_2$S, and pH in sediment pore water beneath marine cage fish farms using a microsensor with a 25 ${\mu}{\textrm}{m}$ sensor tip size. The sediments are characterized by high organic material load. The oxygen consumption, hydrogen sulfide oxidation, and sulfate reduction rates in the microzonations (derived from the vertical distribution of chemical species concentration) were estimated by adapting a simple one-dimensional diffusion-reaction model. The oxygen penetration depth was 0.75 mm. The oxic microzonations were divided into upper and lower layers. Due to hydrogen sulfide oxidation within the oxic zone, the oxygen consumption rate was higher in the lower layer. The total oxygen consumption rate integrated with reaction zone depth was estimated to be 0.092 $\mu$mol $O_2$cm$^{-2}$ hr$^{-1}$ . The total hydrogen sulfide oxidation rate occurring within 0.7 mm thickness was estimated to be 0.030 $\mu$mo1 H$_2$S cm$^{-2}$ hr$^{-1}$ , and its turnover time in the oxic sediment layer was estimated to be about 2 minutes. This suggests that hydrogen sulfide was oxidized by both chemical and microbial processes in this zone. The molar consumption ratio, calculated to be 0.84, indicates that either other electron accepters exit on hydrogen sulfide oxidation, or elemental sulfur precipitation occurs near the $O_2$- H$_2$S interface. Total sulfate reduction flux was estimated to be 0.029 $\mu$mol cm$^{-2}$ hr$^{-1}$ , which accounted for more than 60% of total $O_2$ consumption flux. This result implied that the degradation of organic matter in the anoxic layer was larger than in the oxic layer.

The Effect of Electrode Spacing and Size on the Performance of Soil Microbial Fuel Cells (SMFC) (전극간 거리와 크기가 토양미생물연료전지의 성능에 미치는 영향)

  • Im, Seong-Won;Lee, Hye-Jeong;Chung, Jae-Woo;Ahn, Yong-Tae
    • Journal of Korean Society of Environmental Engineers
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    • v.36 no.11
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    • pp.758-763
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    • 2014
  • Soil microbial fuel cells (SMFC) have gained a great attention as an eco-friendly technology that can simultaneously generate electricity and treat organic pollutants from the contaminated soil. We evaluated the effect of electrode spacing and size on the performance of SMFC treating soil contaminated with organic pollutants. Maximum power density decreased with increase in electrode distance or decrease in electrode size, likely due to higher internal resistance. The maximum voltage and power density decreased from 326 mV and $19.5mW/m^2$ with 4 cm of electrode distance to 222 mV and $5.9mW/m^2$ with 9 cm of electrode distance. In case of electrode size test, the maximum voltage and power density generated was 291 mV, $0.34mW/m^3$ when both of anode and cathode area were $64cm^2$ with 4 cm of electrode distance. The maximum voltage decreased by 19~29% when the anode area decreased to $16cm^2$ while only 3~12% of voltage decreased with cathode area decrease. The maximum power density decreased by 49~68% with decreasing anode size, and by 29~47% with decreasing cathode size. These results showed that the anode area had more significant effects than the cathode area on the power generation of SMFC which has a high internal resistance due to a coexistence of soil and wastewater in the reactor.

Changes of Major Components and Microorganisms during the Fermentation of Korean Ordinary Kochujang (한국재래식(韓國在來式)고추장숙성중(熟成中)의 주요성분(主要成分) 및 미생물(微生物)의 변화(變化))

  • Ahn, Cheol-Woo;Sung, Nack-Kie
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.16 no.3
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    • pp.35-39
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    • 1987
  • The present study was attempted to obtain the basic data concerning a reasonable preparing method and the optimum fermentation conditions of Kochujang (Red pepper paste). To establish the standard qualify of Kochujang, changes of the chemical composition and the numbers of bacteria and feasts in Kochujang during fermentation were observed. Moisture, salts and crude ash contents of Kochujang were not changed significantly during fermentation. Titrable acidity and amino nitrogen gradually increased with the time-passed, whereas crude fat gradually decreased with the time-elapsed. And reducing sugar and total nitrogen increased until 40 days, but slightly decreased after this period. The numbers of bacteria and yeasts in the ingrients for the preparation of Kochujang were $3.9{\times}10^7/g$, $1.5{\times}10^3/g$ in red pepper powder, $7.6{\times}10^4/g$, $2.8{\times}10^2/g$ in salts. respectively, but those of sugar and malt were not more than 100/g. Microbial counts in Kochujang during fermentation increased until 40 days, but those are gradually decreased after that.

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Simultaneous Removal of $NO_x$ and $SO_2$ through the Combination of Sodium Chlorite Powder and Carbon-based Catalyst at Low Temperature ($NaClO_2(s)$와 탄소 분산형 촉매를 이용한 저온에서의 $NO_x$$SO_2$ 동시 제거)

  • Byun, Young-Chul;Lee, Ki-Man;Koh, Dong-Jun;Shin, Dong-Nam
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.1
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    • pp.39-46
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    • 2011
  • NO oxidation is an important prerequisite step to assist the selective catalytic reduction (SCR) at low temperatures ($<200^{\circ}C$). Therefore, we conducted the lab- and bench-scales experiments appling the sodium chlorite powder ($NaClO_2(s)$) for the oxidation of NO to $NO_2$ and the carbon-based catalyst for the reduction of $NO_x$ and $SO_2$; the lab- and bench-scales experiments were conducted in laboratory and iron-ore sintering plant, respectively. In the lab-scale experiment, known concentrations of $NO_x$ (200 ppm), $SO_2$ (75 ppm), $H_2O$ (10%) and $NH_3$ (400 ppm) in 2.6 L/min were introduced into a packed-bed reactor containing $NaClO_2(s)$, then gases produced by the reaction with $NaClO_2(s)$ were fed into the carbon-based catalyst (space velocity = $2,000hr^{-1}$) at $130^{\circ}C$. In the bench-scale experiment, flue gases of $50Nm^3/hr$ containing 120 ppm NO and 150 ppm $SO_2$ were taken out from the duct of iron-ore sintering plant, then introduced into the flow reactor; $NaClO_2(s)$ were injected into the flow reactor using a screw feeder. Gases produced by the reaction with $NaClO_2(s)$ were introduced into the carbon-based catalyst (space velocity = $1,000hr^{-1}$). Results have shown that, in both lab- and bench-scales experiments, NO was oxidized to $NO_2$ by $NaClO_2(s)$. In addition, above 90% of $NO_x$ and $SO_2$ removal were obtained at the carbon-based catalyst. These results lead us to suggest that the combination of $NaClO_2(s)$ with the carbon-based catalyst has the potential to achieve the simultaneous removal of $NO_x$ and $SO_2$ at low temperature ($<200^{\circ}C$).

Comparative Assessment of Specific Genes of Bacteria and Enzyme over Water Quality Parameters by Quantitative PCR in Uncontrolled Landfill (정량 PCR을 이용한 비위생 매립지의 특정 세균 및 효소 유전자와 수질인자와의 상관관계 평가)

  • Han, Ji-Sun;Sung, Eun-Hae;Park, Hun-Ju;Kim, Chang-Gyun
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.8
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    • pp.895-903
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    • 2007
  • As for the increasing demanding on the development of direct-ecological landfill monitoring methods, it is needed for critically defining the condition of landfills and their influence on the environment, quantifying the amount of enzymes and bacteria mainly concerned with biochemical reaction in the landfills. This study was thus conducted to understand the fates of contaminants in association with groundwater quality parameters. For the study, groundwater was seasonally sampled from four closed unsanitary landfills(i.e. Cheonan(C), Wonju(W), Nonsan(N), Pyeongtaek(P) sites) in which microbial diversity was simultaneously obtained by 16S rDNA methods. Subsequently, a number of primer sets were prepared for quantifying the specific gene of representative bacteria and the gene of encoding enzymes dominantly found in the landfills. The relationship between water quality parameters and gene quantification were compared based on correlation factors. Correlation between DSR(Sulfate reduction bacteria) gene and BOD(Biochemical Oxygen Demand) was greater than 0.8 while NSR(Nitrification bacteria-Nitrospira sp.) gene and nitrate were related more than 0.9. A stabilization indicator(BOD/COD) and MTOT(Methane Oxidation bacteria), MCR(Methyl coenzyme M reductase), Dde(Dechloromonas denitrificans) genes were correlated over 0.8, but ferric iron and Fli(Ferribacterium limineticm) gene were at the lowest of 0.7. For MTOT, it was at the highest related at 100% over BOD/COD. In addition, anaerobic genes(i.e., nirS-Nitrite reductase, MCR. Dde, DSR) and DO were also related more than 0.8, which showing anaerobic reactions generally dependant upon DO. As demonstrated in the study, molecular biological investigation and water quality parameters are highly co-linked, so that quantitative real-time PCR could be cooperatively used for assessing landfill stabilization in association with the conventional monitoring parameters.

Biological Activities of Hot Water Extracts Made from Yuza(Citrus junos SIEB ex TANAKA) Peel Cultivated in Namhae (남해산 유자 과피 열수추출물의 생리활성)

  • Shin, Jung-Hye;Yang, Seung-Mi;Kang, Min-Jung;Lee, Soo-Jung;Kim, Sung-Hyun;Sung, Nak-Ju
    • Korean journal of food and cookery science
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    • v.26 no.1
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    • pp.79-87
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    • 2010
  • The antioxidant activity of hot water extracts made from Yuza (Citrus junos SIEB ex TANAKA) cultivated in Namhae Changseon, Seolcheon and Idong-myeon was analyzed. The total phenolic compound content was significantly higher in the Seolcheon sample (116.06 mg/100 g) than in Idong or Changseon. Flavonoids and hesperidin contents were not significantly different among samples. The electron-donating ability of the Yuza peel hot water extracts was activated to over 55% in all samples with $5,000\;{\mu}g/mL$ added to the reaction system, with especially high in the Seolcheon sample (85.70%). Also, the reducing powder in $10,000\;{\mu}g/mL$ added to the reaction system was showed significantly higher in the Seolcheon (0.82) than in the other samples. The ABT cation decolorization capacity of Yuza peel extracts was activated to over 50% in all samples when $5,000\;{\mu}g/mL$ of water extracts were added to the reaction mixture, and the activity was the highest (67.59%) in the Idong samples. The nitric oxide scavenging activity was lower than 45% in all samples, with the activity of Changseon significantely lower than the other samples. The antioxidant activity of the $\beta$-carotene linoleic acid system was 33.30~42.22% when $1,000\;{\mu}g/mL$ water extracts was added to the reaction mixtures, of which the activity in the Yuza cultivated in Seolcheon showed the highest.

Characteristics on De-CH4/NOx according to Ceramic and Metal Substrates of SCR Catalysts for CNG Buses (CNG 버스용 SCR 촉매의 세라믹과 메탈 담체에 따른 De-CH4/NOx 특성)

  • Seo, Choong-Kil
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.1
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    • pp.18-24
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    • 2018
  • The policy-making and technological development of eco-friendly automobiles designed to increase their supply is ongoing, but the internal combustion engine still accounts for about 95% of the automobiles in use. Also, in order to meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is gradually increasing. Natural gas is a clean fuel that emits few air pollutants and has been used mainly as a fuel for city buses. In the long term, we intend to develop a new NGOC/LNT+NGCO/SCR combined system that simultaneously reduces the toxic gases, $CH_4$ and NOx, emitted from CNG buses. The objective of this study is to investigate the characteristics of $de-CH_4/NOx$ according to the ceramic and metal substrates of the SCR (Selective Catalytic Reduction) catalysts mounted downstream of the combined system. The V and Cu-SCR catalysts did not affect the $CH_4$ oxidation reaction, the two NGOC/SCR catalysts each coated with two layers began to oxidize $CH_4$ at $400^{\circ}C$, and the amount of $CH_4$ emitted was reduced to about 20% of its initial value at about $550^{\circ}C$. The two NGOC/SCR catalysts each coated with two layers showed a negative (-) NOx conversion rate above $350^{\circ}C$. The ceramic-based combined system reached LOT50 at $500^{\circ}C$, which was about 20% higher in terms of the $CH_4$ conversion rate than the metal-based combined system, showing that the combined system of NGOC/LNT+Cu-SCR is a suitable combination.