• Title/Summary/Keyword: Sulfide

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$H_2S$ 피독 고분자 전해질막 연료전지의 연료극 성능 회복 연구 (A Study on the Performance Recovery of $H_2S$ Poisoned PEMFC)

  • 이수;진석환
    • 한국응용과학기술학회지
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    • 제29권1호
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    • pp.102-107
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    • 2012
  • 황화수소가 고분자 전해질막 연료전지의 연료극에 공급되었을 때 전지 성능의 저하와 황화수소 피독 후 순환전류 전압법(CV) 스캔을 통해 전지의 성능 회복에 관한 연구를 수행하였다. 수소에 30 ppm의 황화수소를 희석하여 연료극에 공급하고 전류밀도를 $0.5A/cm^2$로 고정하여 1시간 동안 3차례 피독한 후 CV를 5회 스캔하여 단위전지의 성능회복을 확인한 결과 피독 전 단위전지의 초기 성능은 0.60 V에서 $1.16A/cm^2$이였으며, 30 ppm의 황화수소를 한 시간 동안 피독한 결과 $0.77A/cm^2$로 그 성능이 감소하였고, 피독 횟수가 증가함에 따라 성능이 0.57 V까지 감소하였다. 그리고 황화수소 피독 후 각 스텝에서 CV 스캔을 5회 실시하였을 때 단위전지의 성능이 90.3%까지 회복하는 것을 알 수 있었다. 또한, 황화수소 피독 후 단순히 고순도의 수소 가스만 연료극에 주입하여도 약 80% 정도의 성능회복이 가능하였다. 이러한 현상으로 판단할 때 황화수소 가스의 백금 촉매층에의 흡착은 그리 강하지 않음을 알 수 있었다.

Effects of Essential Oils Supplementation on Growth Performance, IgG Concentration and Fecal Noxious Gas Concentration of Weaned Pigs

  • Cho, J.H.;Chen, Y.J.;Min, B.J.;Kim, H.J.;Kwon, O.S.;Shon, K.S.;Kim, I.H.;Kim, S.J.;Asamer, A.
    • Asian-Australasian Journal of Animal Sciences
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    • 제19권1호
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    • pp.80-85
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    • 2006
  • Ninety six crossbred pigs (Landrace${\times}$Yorkshire${\times}$Duroc) were used to determine the effects of essential oils (Fresta F $Conc^{(R)}$) supplementation on growth performance, immune response and fecal noxious gas of weaned pigs. Treatments were 1) NC (negative control; basal diet without antibiotics), 2) PC [positive control; basal diet+CSP (CTC+Sulfathiazole+Penicillin) 0.1%], 3) NCF (basal diet+Fresta F $Conc^{(R)}$ 0.03%) and 4) PCF [basal diet+CSP (CTC+Sulfathiazole+Penicillin) 0.1%+Fresta F $Conc^{(R)}$ 0.02%]. From d 0 to 14, ADFI was increased in pigs fed PCF diet (p<0.05). From d 14 to 28, pigs fed PCF diet had greater ADG and ADFI than pigs fed NC diet (p<0.05). From d 28 to 49, ADG and ADFI in pigs fed PCF diet were higher than in pigs fed NC diet (p<0.05). Through the entire experimental period, ADG and ADFI in pigs fed PCF diet were the highest compared to pigs fed NC and PC diets (p<0.05). There was no significant difference in fecal consistency score among the treatments (p>0.05). No statistical differences (p>0.05) were found in red blood cells (RBC) counts, white blood cells (WBC) counts, lymphocyte counts, total protein and albumin. Serum IgG concentration of PCF treatment was greater than that of other treatments (p<0.05). From d 0 to 14, there was no significant difference in digestibility of dry matter and nitrogen among the treatments (p>0.05). From d 14 to 28, digestibility of dry matter in pigs fed PC, NCF and PCF diets was higher than that of pigs fed NC diet (p<0.05) and treatments with added essential oils were higher than other diets on digestibility of nitrogen (p<0.05). Also, from d 28 to 49, digestibility of nitrogen in pigs fed PCF diet was the highest among others (p<0.05). On d 14 and 28, no statistical differences (p>0.05) were found in volatile fatty acid (VFA), ammonia nitrogen ($NH_3$-N) and hydrogen sulfide ($H_2S$) concentrations among treatments. On d 49, there was no significant difference in VFA concentration among the treatments (p>0.05). $NH_3$-N concentration in pigs fed PCF diet was lower than in pigs fed other diets (p<0.05). $H_2S$ concentration in pigs fed diets with added essential oils was lower than others. In conclusion, the results suggest that the dietary addition of essential oils and antibiotics into diets for weanling pigs improved growth performance, IgG concentration and nitrogen digestibility and decreased noxious gas concentration. Essential oils can be used to partly replace antibiotics in diets for weaned pigs without negative affects on growth performance.

The Effects of Different Copper (Inorganic and Organic) and Energy (Tallow and Glycerol) Sources on Growth Performance, Nutrient Digestibility, and Fecal Excretion Profiles in Growing Pigs

  • Huang, Y.;Yoo, J.S.;Kim, H.J.;Wang, Y.;Chen, Y.J.;Cho, J.H.;Kim, I.H.
    • Asian-Australasian Journal of Animal Sciences
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    • 제23권5호
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    • pp.573-579
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    • 2010
  • This study was conducted to determine the effects of different copper (inorganic and organic) and energy (tallow and glycerol) sources on growth performance, nutrient digestibility, gas emission, diarrhea incidence, and fecal copper concentration in growing pigs by using a 2${\times}$2 factorial design. In this trial, 96 pigs (63 d of age) were employed, with an average initial weight of 28.36${\pm}$1.14 kg. The dietary treatments were i) basal diet with 134 ppm copper (Korea recommendation) as $CuSO_4$+tallow; ii) basal diet with 134 ppm Cu as $CuSO_4$+glycerol; iii) basal diet with 134 ppm copper as CuMet+tallow; and iv) basal diet with 134 ppm copper as CuMet+ glycerol. Throughout the entire experimental period, no differences were noted among treatment groups with regard to the magnitude of improvement in ADG (average daily gain), ADFI (average daily feed intake) and G/F (gain:feed) ratios. The nitrogen (N) digestibility of pigs fed on diets containing organic copper was improved as compared with that observed in pigs fed on diets containing inorganic copper (p<0.05). An interaction of copper${\times}$energy was observed in the context of both nitrogen (p<0.05) and energy (p<0.01) digestibility. Ammonia emissions were significantly lower in the organic copper-added treatment groups than in the inorganic copperadded treatment groups (p<0.05). Mercaptan and hydrogen sulfide emissions were reduced via the addition of glycerol (p<0.05). No significant effects of copper or energy source, or their interaction, were observed in reference to diarrhea appearance and incidence throughout the entirety of the experimental period. The copper concentration in the feces was significantly lower in the organic copper source treatment group than was observed in the inorganic copper source treatment group (p<0.05). The results of this experiment show that organic copper substituted for inorganic copper in the diet results in a decreased fecal copper excretion, but exerts no effect on performance. The different energy (tallow and glycerol) sources interact with different copper sources and thus influence nutrient digestibility. Glycerol supplementation may reduce the concentrations of odorous sulfuric compounds with different Cu sources.

국내 녹색-청색계열 무기안료의 산출과 광물학적 특성 (Occurrence and Mineralogical Properties of Green-Blue Inorganic Pigments in Korea)

  • 정기영;조현구;도진영
    • 한국광물학회지
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    • 제31권1호
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    • pp.33-46
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    • 2018
  • 단청, 불화, 벽화 등에 사용된 전통 무기질 안료는 대부분 광물이었으나, 근현대에 저렴한 화학안료로 대체되어 광물안료 제조법의 맥이 끊어졌다. 이 연구에서는 문화재 보존에 필요한 전통 광물안료 중 녹색-청색 계열 안료자원의 국내 산출과 광물학적 특성을 규명하고자 하였다. 구리를 함유한 녹색 - 청색 안료광물들은 구리-납-아연을 채굴하는 금속광산의 폐석장이나 갱내 풍화대에서 이차광물로 산출되었다. X선회절과 주사전자현미경 분석을 이용하여 광물동정을 실시한 결과, 녹색은 brochantite, devilline, 청색은 linarite, bechererite, schulenbergite 등의 함수구리황산염이 대표적인 발색광물이었으며, 그 외 소량의 녹색 antlerite, atacamite가 확인되었다. 이들 녹색-청색 안료광물과 함께 cerussite, smithsonite, anglesite, cuprite 등이 이차광물로 흔히 수반되었다. 녹색 규산염 안료인 뇌록은 현무암 파쇄대의 교대산물로 산출되며, 주발색광물인 celadonite 외에 단백석이 다양한 비율로 혼재되어 있었다. 녹색 규산염 안료인 해록석은 사질 서해 퇴적물 내에서 산출이 확인되었다. 이번 조사에서 대표적인 구리계열 녹색-청색 전통안료로 알려진 공작석과 남동석의 산출을 확인할 수 없었다.

만장광상 중앙광체와 본광체의 광화작용과 생성환경 (Mineralization and Genetic Environments of the Central and Main Orebodies in the Manjang Deposit, Goesan)

  • 유현민;신동복
    • 한국광물학회지
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    • 제31권2호
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    • pp.87-101
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    • 2018
  • 만장광상은 옥천변성대 화전리층 내에 발달되었으며 열극충전형 동광체인 중앙 및 본광체와 철 스카른형 서부광체로 대분된다. 본 연구에서는 중앙 및 본광체에 대한 광상학적 연구를 수행하여 기존 서부광체 광화작용 특성과 비교하고자 한다. 중앙광체는 맥상조직이 두드러지며 자류철석과 황동석이 주를 이루는 반면, 본광체는 맥상, 괴상, 각력상 조직과 더불어 황철석, 유비철석, 황동석이 주로 산출된다. 이 밖에 섬아연석, 방연석, 자철석, 티탄철석, 금홍석, 석석, 철망간중석, 황석석 등이 수반된다. 스카른이 부분적으로 발달하며 석류석은 그로슐라 계열, 휘석은 헤덴버자이트 계열이 우세한 것으로 보아 대체로 환원환경에서 정출된 것으로 보인다. 중앙광체의 섬아연석-황석석과 본광체의 황철석-유비철석 광물공생군을 이용한 생성온도는 각각 $204-263^{\circ}C$, $383-415^{\circ}C$로서 중앙광체가 상대적으로 낮고, 황분압도 본광체에서 $10^{-6}-10^{-7}atm$로서 비교적 높고 중앙광체로 가면서 점차 감소한 것으로 보인다. 황화광물의 황동위원소조성은 중앙광체 4.6-7.9‰, 본광체 4.3-7.0‰로 상호 유사하며 주로 화성기원이지만 모암의 영향으로 약간 높게 나타난다. 광석광물의 종류와 조직 그리고 광화작용의 물리화학적 조건을 고려할 때 동광화작용이 발달한 본광체와 중앙광체는 잠두화성암에 대하여 각각 근지성과 원지성 광화작용의 특성을 나타낸 것으로 보이며, 스카른 철광상이 발달한 서부광체와는 서로 다른 열수계의 영향을 받아 생성된 것으로 여겨진다.

마산항 표층 퇴적물의 유기물 및 금속원소의 분포 (Distribution of Organic Matters and Metallic Elements in the Surface Sediments of Masan Harbor, Korea)

  • 황동운;진현국;김성수;김정대;박종수;김성길
    • 한국수산과학회지
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    • 제39권2호
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    • pp.106-117
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    • 2006
  • We measured the concentrations of organic matter and metallic elements (Al, Fe, Cr, Mn, Ni, Cu, Zn, As, Cd, Pb and Hg) in the surface sediments of Masan Harbor (in the southern sea, Korea) to evaluate the geochemical characters of sediment and the pollutions by organic matter and metallic elements. The mean grain size of the surface sediments in the study area ranged from $5.6{\phi}$ to $7.8{\phi}$, indicating silt sediment. The water content of the surface sediments exceeded 60% except at some stations. The contents of ignition loss (IL), total organic carbon (TOC) and total nitrogen (TN) ranged from 7.2-14.3%, 1.2-3.2%, and 0.10-0.28%, respectively. Based on the C/N ratios, the organic matter in the surface sediments of Masan Harbor may originate from terrigenous sources including fluvial inputs (mainly sewage in urban areas). The chemical oxygen demand (COD) and acid volatile sulfide (AVS) ranged from $11.3-29.9\;mgO_2/g\;dry$ and 0.20-4.47 mgS/g dry, respectively, and low concentrations were observed near a shipping route. In addition, the concentrations of metallic elements showed large spatial variations in Masan Harbor and the distributions of metallic elements were also comparable to those of organic matter. This implies that the distributions of organic matter and metallic elements in the surface sediments of Masan Harbor are mainly controlled by biogenic matter and artificial action (mainly dredging). In addition, we calculated the enrichment facto. (EF) and geoaccumulation index (Igeo) in order to evaluate pollution by metallic elements. The enrichment of metallic elements relative to Al was three to eighteen times higher at the study sites, compared to levels in the Earth's crust except for Fe, Ni and Mn. In addition, the Igeo class indicated that the surface sediments in the study area were moderately to strongly polluted in terms of metallic elements.

한국 서해남부 조간대 표층 퇴적물의 지화학적 특성 (Geochemical Characteristics of Intertidal Surface Sediments along the Southwestern Coast of Korea)

  • 황동운;류상옥;김성길;최옥인;김성수;고병설
    • 한국수산과학회지
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    • 제43권2호
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    • pp.146-158
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    • 2010
  • In order to evaluate the characteristics of sediments and pollution by organic matter and metallic elements in intertidal sediments along the southwestern coast of Korea, we measured various geochemical parameters, including the mean grain size (Mz), water content (WC), ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and metallic elements (Al, Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, As), in intertidal surface sediments. The Mz of the surface sediments ranged from 2.1 to 8.3$\phi$, indicating that the surface sediments consist of various sedimentary facies, such as sand, slightly gravelly mud, sandy mud, and silt. The IL and COD in surface sediment ranged from 0.8 to 5.5% (mean $2.9\pm1.2%$) and from 3.9 to $13.8\;mgO_2/g{\cdot}dry$ (mean $8.5\pm2.6\;mgO_2/g{\cdot}dry$), respectively, which were lower than the values for surface sediment in areas near fish and shellfish farms or industrial complexes. No AVS was detected at any sampling station, despite various sedimentary facies. Most of metallic elements in surface sediments showed relatively good positive correlations with Mz and IL, which imply that the concentrations of metallic elements are mainly controlled by grain size and the organic matter content. The concentrations of metallic elements, except As, at some stations were considerably lower than those in the Sediment Quality Guideline (Effect Range Low, ERL) proposed by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Similarly, the geoaccumulation index (Igeo) class indicated that pollution by metallic elements in intertidal surface sediment, except As, was moderate or non-existent. Our results imply that the intertidal surface sediments along the southwestern coast of Korea are not polluted by organic matter and metallic elements and are healthy for benthic organisms.

변산반도 조간대 표층 퇴적물의 퇴적률 및 저서환경 변화 (Temporal Variations in the Sedimentation Rate and Benthic Environment of Intertidal Surface Sediments around Byeonsan Peninsula, Korea)

  • 정래홍;황동운;김영길;고병설;송재희;최희구
    • 한국수산과학회지
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    • 제43권6호
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    • pp.723-734
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    • 2010
  • To understand temporal variations in geochemical characteristics of intertidal surface sediments around Byeonsan Peninsula (in the middle of the western coast, Korea) after the construction of Saemanguem dyke, the sedimentation rate and various geochemical parameters, including mean grain size (Mz), water content (WC), ignition loss (IL), chemical oxygen demand (COD), and acid volatile sulfide (AVS), were measured along four transects (A.D lines) at monthly intervals from February 2008 to March 2009. The average monthly sedimentation rate ranged from -5.3 to 3.8 mm/month (mean $-0.8{\pm}2.7\;mm$/month), which showed an erosion-dominated environment in the lower part of the intertidal zone. In addition, surface sediments were eroded in summer and autumn, but were deposited in spring and winter. The Mz of surface sediments ranged from -0.8 to $3.4{\varnothing}$ (mean $2.8{\pm}0.5{\varnothing}$), indicating that the surface sediments consist of coarser sediments (sand and slightly gravelly sand). The Mz of surface sediments did not show large monthly and/or seasonal variations, although the sedimentation rates of surface sediment showed large seasonal variation. This may be due to lateral shifting and effective dispersion of surface sediments by wind, tide, and longshore current. The concentrations of IL and COD in the surface sediments ranged from 0.2 to 2.9% (mean $1.4{\pm}0.4%$) and from 0.2 to $18.5\;mgO_2$/g-dry (mean $3.9{\pm}3.4\;mgO_2$/g-dry), respectively, which were slightly higher in spring than in the other seasons. This may be related to spring blooms of phytoplankton in seawater and/or benthic microalgae in surface sediments. On the other hand, no AVS concentrations were detected in surface sediments at any of the sampling stations during the study period.

주류의 풍미 및 품질 향상을 위한 야생 효모의 분리 및 특성분석 (Isolation and Characterization of Wild Yeasts for Improving Liquor Flavor and Quality)

  • 백성열;이유정;김재현;여수환
    • 한국미생물·생명공학회지
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    • 제43권1호
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    • pp.56-64
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    • 2015
  • non-Saccharomyces 효모는 야생효모로서, 다양한 효소를 세포 밖으로 분비하여 와인의 향기 성분 증가에 중요한 영향을 준다고 알려져 있다. 본 연구에서는 한국의 발효식품에서 분리된 효모 1,007주의 세포외 효소 활성을 조사하였다. 그 결과, β-glucosidase 566, glucanase 45, protease 401로 나타났으며, AA decarboxylase 활성 균주는 각 아미노산 별로 His 69, Tyr 306, Phe 171, Trp 23, Lys 197, Leu 198 균주로 나타났다. Cerulenin 과 TFL 내성 균주는 각각 563, 610주로, 15% 에탄올 내성 균주는 307주로 나타났다. 황화수소 생성균은 500주로 조사되었다. AA decarboxylation와 황화수소 저생성 균주 중 유용 효모 12 균주를 선발하여 26S rDNA 염기서열을 분석한 결과, C. tropicalis, H. opuntiae, H. uvarum, P. kudriavzevii, S. cerevisiae, W. anomalus로 각각 동정되었다. 12주의 효모 중 당 내성 우수 균주는 9주이며, 알코올 내성 우수 균주는 5 균주로 나타났다. 알코올 발효능은 Saccharomyces 효모는 8% 이상으로 나타났으며, non-Saccharomyces 효모는 3% 내외로 나타났다.

아프리카 말리 세폴라 지역의 금광화작용:금의 산출특성 및 유체포유물연구 (Gold Mineralization of the Sepola District in Mali, Africa: Occurrence Characteristics of Gold and Fluid Inclusion Study)

  • 허철호
    • 자원환경지질
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    • 제42권3호
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    • pp.167-175
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    • 2009
  • 아프리카 말리 세폴라 지역의 지질은 하부로부터 하부원생대의 변성퇴적암류 및 화산쇄설성암류로 구성된 비리미안층군과 후기에 이를 관입한 화성암류로 구성된다. 본역의 광상은 비리미안층군내 북서주향의 대규모 단층대 생성과 관련하여 2차적으로 형성된 열극대를 따라 열수유체가 충진되어 형성된 맥상 및 광염상 금광상이다. 부존잠재성이 가장 기대되는 바라니 구역은 연장 1.3 km, 폭 1${\sim}$20.1m, 품위 Au 0.53${\sim}$9.21 g/t가 확인되었다. 광석광물은 단순하며, 에렉트럼, 황철석 및 방연석 등이 확인되었다. 금립의 순도는 848${\sim}$915(평균 891)이며 본역 내 금광상은 중${\sim}$심열수 환경에서 생성되었음을 추정할 수 있다. 유체포유물은 액상우세(형), 기상우세 (형) 및 액상함$CO_2$ 포유물(형)로 분류된다. 초생 및 가이차 포유물의 균일화온도는 236${\sim}$393$^{\circ}C$, NaCl상담 염농도는 0.0${\sim}$8.6 wt.%이며, 이차포유물의 균일화 온도는 103${\sim}$184$^{\circ}C$, 염농도는 0.7${\sim}$8.6 wt.%이다. 균일화온도 및 염농도관계로부터 유체는 400${\sim}$250$^{\circ}C$범위에서는 압력감소에 의한 유체불혼화 과정을 거친후 천수의 유입으로 희석 및 냉각과정이 이루어졌음을 알 수 있다. 석영맥이 괴상을 보이고 광물수반양상이 단순한 점, 유화광물이 소량 함유되고, 함$CO_2$ 포유물이 산출되고 균일화온도가 높은 것등으로부터 본역내 금광화작용은 중-심열수형 광상으로 사료된다.