검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 54

        21.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 1차 아민(MEA, monoethanolamine)으로 개질한 입자상 활성탄(WSC-470)을 이용하여 실내 저농도 이산화탄소를 제거하고자 하였다. MEA 함침농도(6.1~42.7 wt.%)와 용매제(distillate water, ethanol, methanol) 종류에 따라 제조된 흡착제의 특성분석(BET, pore property, XPS)과 각 흡착제의 CO2가스에 대한 최대 흡착능, 3000 ppm의 저농도 CO2분위기에서의 흡착량을 측정하였다. MEA 농도가 증가할수록 물리적 특성인 비표면적, 공극률, 미세기공률 등은 감소한 반면, 표면 염기도 향상에 기여하는 질소 함량은 증가하였다. 이러한 물성변화로 인해 최대 흡착능은 초기 활성탄(RAC: 3.27 mmol/g) 대비 최대 71%(AC-MM(42.7, 40): 0.937 mmol/g)가 감소한 반면, 저농도 이산화탄소에 대한 선택적 흡착량은 45%(AC-MM(15.3, 40): 0.73 mmol/g)의 향상을 보였다.
        4,000원
        22.
        2013.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Graphene has been synthesized on 100- and 300-nm-thick Ni/SiO2/Si substrates with CH4 gas (1 SCCM) diluted in mixed gases of 10% H2 and 90% Ar (99 SCCM) at 900˚C by using inductively-coupled plasma chemical vapor deposition (ICP-CVD). The film morphology of 100-nm-thick Ni changed to islands on SiO2/Si substrate after heat treatment at 900˚C for 2 min because of grain growth, whereas 300-nm-thick Ni still maintained a film morphology. Interestingly, suspended graphene was formed among Ni islands on 100-nm-thick Ni/SiO2/Si substrate for the very short growth of 1 sec. In addition, the size of the graphene domains was much larger than that of Ni grains of 300-nm-thick Ni/SiO2/Si substrate. These results suggest that graphene growth is strongly governed by the direct formation of graphene on the Ni surface due to reactive carbon radicals highly activated by ICP, rather than to well-known carbon precipitation from carbon-containing Ni. The D peak intensity of the Raman spectrum of graphene on 300-nm-thick Ni/SiO2/Si was negligible, suggesting that high-quality graphene was formed. The 2D to G peak intensity ratio and the full-width at half maximum of the 2D peak were approximately 2.6 and 47cm-1, respectively. The several-layer graphene showed a low sheet resistance value of 718Ω/sq and a high light transmittance of 87% at 550 nm.
        4,000원
        24.
        2012.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In order to enhance the selective adsorption of CO2, the surface of granular activated carbon (GAC) was modified by an ammonia solution. Ammonia in an aqueous phase could be decomposed into NH4+, OH- and other N-containing elements. The present work attempted to impregnate some basic functional groups leading to chemisorption of the activated carbon surface. While the addition of N-groups reduced the specific surface area from 2071.4 m2/g to about 1300-1400 m2/g, the adsorption capacity for CO2 increased to a certain degree, and the best amination could be achieved with the reaction at 100℃ for 12 hours. The enhanced adsorption capacity could be obtained by formation of nitrogen functionalities such as amine, pyrrolic groups and pyridine oxides which were verified by XPS analysis.
        4,000원
        26.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        탄소막은 고분자막에 비해 높은 선택성과 투과성, 열적, 화학적 안정성을 가지고 있어 기체 분리, 특히 휘발성 유기화합물(VOCs) 분리막으로 많은 관심을 받고 있다. 활성탄소중공사막은 기공 표면(pore wall)에 형성된 흡착성 미세기공에 의해 선택적으로 응축성 성분이 흡착, 확산되는 흡착-확산 기구에 의해 흡착성-비흡착성 물질이 분리된다. 본 연구에서는 다공성 알루미나 중공사막 지지체에 phenolic resin (novolac type)을 코팅한 후 산화, 탄화 및 활성화 등의 열분해 과정을 통해 막 표면과 기공 표변에 흡착성 미세기공이 형성된 활성탄소중공사막을 제조하였다. 또한 열분해 조건에 따른 phenol/alumina 복합 활성탄소중공사막의 물리적 특성과 기체 투과특성에 대해 살펴보았다. 그 결과, 제조된 phenol/alumina 복합 활성탄소중공사막이 휘발성 유기물질의 대부분을 차지하고 있는 탄화수소를 선택적으로 분리 회수하는데 매우 효과적인 특성을 갖고 있음을 확인할 수 있었다. 따라서 본 연구에서 개발된 phenol/alumina 복합 활성탄소중공 사막은 VOCs의 분리, 농축에 매우 효과적으로 활용 가능할 것으로 기대된다.
        4,000원
        27.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A carbon doped (C-) photocatalyst, which shows good photocatalytic activity to Ultraviolet irradiation and visible irradiation, was successfully prepared by co-grinding of with ethanol or Activated Carbon(C), followed by heat treatment at in air for 60 min. Ethanol and C were used as a representative agent of liquid and solid for carbon doping. Their influence on improving photocatalytic ability and carbon doping degree was studied with degradation of methyl orange and XPS analysis. The product prepared by co-grinding of with Ethanol had Ti-C and C-O chemical bonds and showed higher photocatalytic activity than the product prepared by co-grinding of with C, where just C-O chemical bond existed. As a result, mechanochemical route is useful to prepare a carbon doped photocatalyst activating to visible irradiation, where the solid-liquid operation is more effective than solid-solid operation to obtain a carbon doped .
        4,000원
        29.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research was conducted to estimate the characteristics of carbon dioxide decomposition using an inorganic sludge. The inorganic sludge was composed of high amount (66.8%) of Fe2O3. Hydrogen could be reduced with 0.247, 0.433, 0.644, and 0.749 at 350, 400, 450, and 500℃, respectively. The carbon dioxide decomposition rates at 250, 300, 350, 400, 450, and 500℃ were 32, 52, 35, 62, 75, and 84%, respectively. High temperature led to high reduction of hydrogen and better decomposition of carbon dioxide. The specific surface area of the sludge after hydrogen reduction was higher than that after carbon dioxide decomposition. The specific surface area of the sludge was more decreased with increasing of temperature.
        4,000원
        30.
        2006.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Bioaerosols are airborne particles of biological origins including viruses, bacteria, fungi, and all varieties of living materials. In suitable hosts, bioaerosols are capable of causing acute or chornic diseases that may be infectious, allergenic, or toxigenic. Bioaerosols from outdoor air accumulate on filters of heating, ventilating and air conditioning (HVAC) system in large quantities and are able to multiply there under certain conditions. In this study, silver was coated on activated carbon fiber (ACF) filters by an electroless plating method, and their efficacy for bioaerosols removal was tested. Physical filtration and biological antimicrobial test were performed. SEM and XRD analyses were used to characterize the morphology and components of ACF filters. Electroless silver-plated ACF filters showed antimicrobial efficiency, whereas pure ACF filters did not. It was found that electroless silver plating did not influence the physical filtration efficiency of ACF filters.
        4,000원
        31.
        2005.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        OXI-PAN fibers, Kynol fibers and rayon fibers were used as precursorsfor the preparation of activated carbon fibers (ACFs) by chemical activation with KOH at 800℃. The effects of different precursorfibers and fiber/KOH ratios on the final ACFs are discussed. The precursor fibers used are appropriate for the ACFs in a single stage pyrolysis process. The OXI-PAN fibers which were activated with KOH of 2.0M showed a specific surface area of 2328m2/g however, loosed the fiber shape because of low yields. The Kynol fibers and Rayon fibers showed the high yields but the lower specific surface area of 900m2/g and 774m2/g, respectively, at KOH of 1.5M. The OXI-PAN fibers which were activated with KOH of 1.5M have a specific surface area of 1028m2/g and higher micro-pore volumes and lower yields rather than Kynol-1.5 and Rayon-1.5 samples. This phenomenon is because of higher chemical resistance of the Kynol and Rayon fibers rather than OXI-PAN fibers. However, the Kynol fibers were the best precursors on KOH activation at 800℃ considered carbon yields, surface areas and micropore volumes.
        4,000원
        34.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        산초종피 메탄을 추출물과 hyperoside의 사전투여가 사염화탄소에 의해 예상되는 혈청지질성분의 농도변화에 미치는 효과를 밝히기 위해 TCR계 mouse를 대상으로 실험한 결과는 다음과 같다. 사염화탄소로 혈청 총콜레스테를 농도가 유의적으로 증가되었으나, 산초 메탄올 추출물과 hyperoside의 사전투여는 사염화탄소에 의한 이의 증가를 유의적으로 억제시켰으며, 20㎎/㎏ hyperoside 투여군에서 그 효과가 가장 높았다. 사염화탄소로 혈청 HDL-cholesterol 농도가 유의적으로 감소되었으나, 산초 메탄올 추출물과 hyperoside의 사전투여는 사염화탄소에 의한 이의 감소를 유의적으로 억제시켰으며, 20㎎/㎏ hyperoside 투여군에서 그 효과가 가장 높았다. 사염화탄소로 혈청 LDL-cholesterol 농도가 유의적으로 증가되었으나 산초 메탄올 추출물과 hyperoside의 사전투여는 사염화탄소에 의한 이의 증가를 유의적으로 억제시켰으며, 20㎎/㎏ hyperoside 투여군에서 그 효과가 가장 높았다. 사염화탄소로 혈청 triglyceride 농도가 유의적으로 증가되었으나, 산초 메탄올 추출물과 hyperoside의 사전투여는 사염화탄소에 의한 의의 증가를 유의적으로 억제시켰다.
        4,000원
        35.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There appeared enhancements of the conversion of methane by adding a small amount of CO in the aromatization reaction of methane using the Mo-zeolite catalyst. In case of adding CO2, CO2 changed to CO first, and then the conversion reaction occurred. It was observed by using isotopes as reactants that CO is related to the aromatization reaction of methane.
        4,000원
        36.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Electrochemical charateristics of activated carbon fiber cloth(ACFC) electrode were studied with propylene carbonate(PC), γ-butyrolactone(GBL) and N,N-dimethyl-formamide(DMF) as a solvent and tetraethylammoniumtetrafluoroborate(TEABF4), tetraethylammoniumhexafluorophosphate(TEABF6), tetrabutylammoniumtetrafluoroborate(TBABF4) and tetrabutylammonium hexafluorophosphate(TBAPF6) as an electrolytes(active material). The concentrations of electrolytes were in the range of 0.2~1.2 N, the volume ratios of PC and DMF as a mixed solvent system, were 90:10, 80:20, 70:30, 60:40, 50:50, and 40:60 vol%. Electrochemical characteristics such as electric conductivity, internal resistance, and electric capacitance of fabricated unit cells were measured after the moisture of activated material was removed with molecular sieve. Electrochemical characteristics were better in mixed solvents system than in mono solvent system. The mono solvent system of 1.0 N electrolyte of GBL/TEABF4 with activated carbon cloth electrodes showed better result but the mixed solvent system with PC and DMF/TEABF4(50:50 vol%) and the concentration of 1.0 N electrolyte showed the best characteristics. Internal resistance was 3.47 Ω and specific capacitance was 19.1 F/g respectively.y.
        4,600원
        37.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Previous studies have shown that methanol extract and its butanol fraction of Carthamus tinctorius L. Semen have the hepatoprotective effect on the CCl₄ induced hepatotoxicity. The hepatoprotective effect of the subfractions of butanol fraction has been evaluated by analyzing oxygen free radical scavenging enzyme activities and histopathological examinations. In BS-5 subfraction treated group, the activity of superoxide dismutase has been significantly increased as compared with that of CCl₄ treated rats. Antioxidant activity has been evaluated by the examination of the scavenging activity against 1,1-diphenyl-2-picrylhydrazyl radical. BS-5 subfraction has shown strong antioxidant activities. The histopathological examination showed that the treatment of BS-5 subfraction has relieved the ballooning degeneration of hepatocytes which had been generated by CCl₄. It appears that the protective effect of BS-5 subfraction would be mediated of the attenuation of lipid peroxidation by acting as a free radical scavenger, which were based on the increase of superoxide dismutase activity.
        4,000원
        38.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Previous studies have shown that methanol extract and its butanol fraction of Carthamus tinctorius L. Semen have the hepatoprotective effect on the CCl₄-induced hepatotoxicity. The hepatoprotective effect of subfractions has been evaluated by analyzing blood and hepatocyte biochemical analyses and biotransformation enzyme analyses. Treatment of BS-5 subfraction has significantly decreased the activities of alanine aminotransferase and aspartate aminotransferase. In addition, the levels of cholesterol and triglyceride in liver have been decreased as compared with that of CCl₄ treated rats. The hepatoprotective effect of BS-5 subfraction on the CCl₄-induced hepatotocicity would be mediated of the attenuation of the level of cytochrome P450 and the enhancement of the activity of glutathion S-transferase.
        4,000원
        1 2 3