• 제목/요약/키워드: oxidation-reduction

검색결과 1,450건 처리시간 0.024초

Facile Synthesis of Hollow CuO/MWCNT Composites by Infiltration-Reduction-Oxidation Method as High Performance Lithium-ion Battery Anodes

  • Zheng, Gang;Li, Zhiang;Lu, Jinhua;Zhang, Jinhua;Chen, Long;Yang, Maoping
    • Journal of Electrochemical Science and Technology
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    • 제11권4호
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    • pp.399-405
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    • 2020
  • Hollow copper oxide/multi-walled carbon nanotubes (CuO/MWCNT) composites were fabricated via an optimized infiltration-reduction-oxidation method, which is more facile and easy to control. The crystalline structure and morphology were characterized by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The as-prepared CuO/MWCNT composites deliver an initial capacity of 612.3 mAh·g-1 and with 80% capacity retention (488.2 mAh·g-1) after 100 cycles at a current rate of 0.2 A·g-1. The enhanced electrochemical performance is ascribed to the better electrical conductivity of MWCNT, the hollow structure of CuO particles, and the flexible structure of the CuO/MWCNT composites.

정밀여과법 하수재이용 공정에서 오존의 전처리 효과에 관한 연구 (Effect of Ozonation in Microfiltration Membrane for Wastewater Reuse)

  • 문성용;안세혁;이상협;박종훈;홍석원;최용수
    • 상하수도학회지
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    • 제20권4호
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    • pp.535-543
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    • 2006
  • The Ozone oxidation process was applied to increase the efficiency of reuse process when treating the secondary effluent by the membrane system. This paper focus on decreasing efficiency of membrane fouling, because of membrane fouling reduction by ozone and evaluation of application of the ozone oxidation. The feed water was secondary effluent from BNR process. The result shows that the ozone pretreatment can reduce membrane fouling effectively. Also, the improvement of treated water quality was obvious. The reduction of the membrane fouling led decrease of following pollutant and increase of lnner adsorptive ability of hydrophilic organic matter and decrease of molecular weight. MF membrane process alone can meet the domestic reuse water standards. And ozone pretreatment process also can increase the removal rates of turbidity, COD, nitrogen, and color.

SOx저감을 위한 DOC에 관한 실험적 연구 (An Experimental Study on SOx Reduction in Diesel Engine)

  • 오용석;박봉규
    • 한국대기환경학회지
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    • 제14권3호
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    • pp.261-266
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    • 1998
  • Recently, air pollution is increased according to increase of vehicle. So many countries are studying about DOC for diesel emission decrease. However, there are many difficulty in applying to DOC . In this study, SOx exhaust gas equipped with DOC was studied and we obtained several test results as following. First, in diesel oxidation catalyst, additives such as Pt is very effective for 503 and sulfate. Second, the oxidative activity for 502 has decreased to add such as Pt and the decrease of 502 is effect for the reduction of PM in high temperature . And finally, in high temperature, concentration of SOx is increased and temperature is affected by process from SOB to 503, whereas engine performance and fuel consumption are not affected by equipped DOC.

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Cyclitol 유도체 합성에 관한 연구 (제4보) DL-epi-inosose-2의 전해환원 (Synthesis of Cyclitol Derivatives (IV) Electrolytic Reduction of DL-epi-inosose-2)

  • 손주환;남종우;박흥조
    • 대한화학회지
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    • 제16권2호
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    • pp.93-99
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    • 1972
  • To obtain the various kinds of inositol stereomers, we have selected the process of electrolytic reduction of DL-epi-inosose-2 using Ni, Ta, Cu, Mo, Pb, Sn, W, Cd and Hg etc., as cathode. We think that this process gives greater variety than chemical processes. DL-epi-inosose-2 was synthesized by chemical oxidation of myo-inositol, dissolved in aqueous solution of potassium hydroxide, and used as electrolytic solution. To prevent anodic oxidation of cathode products the H-type diaphragm cell was used. As the results of paper chromatography of cathodic products, we obtained the $R_f$ values of myo-inositol and epi-inositol were in good agreement with literature values.

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산화 바나듐 박막의 상변화 (Phase Changes of Vanadium Oxide Thin Films)

  • 선우진호;신인하;고경현;안재환
    • 한국표면공학회지
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    • 제25권6호
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    • pp.293-298
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    • 1992
  • Various vanadium-oxide thin films were deposited by e-beam and thermal evaporation of V2O5, V2O3, and VO2 powders. Films with thickness of $2000\AA$ were subjected to annealing at $300^{\circ}C$~$450^{\circ}C$ in N2 atmosphere for the crystallization and desification purposes. For the films deposited from V2O5 and VO2 sources, sources, Magneli (VnO2n-1$ 4\leq$ $n\leq$ 8) and VO2 phase appeared at $300^{\circ}C$, respectively, but VO2 phase also transformed into Magneli phase at $450^{\circ}C$ by severe reduction. On the contrary, VO2/VO mixed phases resulted from congruent evaporation of V2O3 unchanged after the same annealing treatment due to the balanced reduction and oxidation of VO2 and VO whcih have different equilibrium O2 pressures. It is suggested that the annealing in the controlled oxidation atmosphere or the deposition using mixed oxide sources are necessary to get the film containing VO2 phase.

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마이크로파를 이용한 SHS 방법에 의한 분말의 산화-환원반응 (Microwave Induced Reduction/Oxidation Reaction by SHS Technique)

  • 김석범
    • 한국결정학회지
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    • 제9권1호
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    • pp.44-47
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    • 1998
  • 가정용 2.45GHz 마이크로파 오븐을 사용하여 A1 금속분말과 SiO2 분말간에 SHS방법에 의하여 산화/환원 반응을 통한 Al2O3 분말과 Si분말간의 복합체를 얻을 수 있었다. 분말간의 반응을 일으키기 위한 온도까지 승온시키기 위하여는 SiC 분말을 susceptor로 이용한 마이크로파 복합가열(Microwave Hybrid Heating)방법을 사용하여 분당 100℃의 승온 속도로 가열하였으며 반응은 850℃ 근처에서 일어났으며 가열 속도는 반응이 시작되면서 분당 200℃ 이상의 온도상승이 일어나면서 원하는 반응을 얻을 수 있었다.

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생물학적 질소 제거공정에서 ORP 측정을 통한 외부탄소원의 자동 주입 제어 (Automatic Addition Control of the External Carbon Source by the Measurement of ORP in Biological Nitrogen Removal Process)

  • 신춘환
    • 한국환경과학회지
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    • 제21권3호
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    • pp.383-390
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    • 2012
  • For the cost-effective biological nitrogen removal (BNR) process whose characteristics of influent have low COD/N ratios, the automatic control system for the addition of external carbon based on oxidation-reduction potential (ORP) data in an anoxic reactor has been developed. In this study, it was carried out with a pilot-scale Bardenpho process which was consisted of anoxic 1, aerobic 1, aerobic 2, anoxic 2, aerobic 3 tank and clarifier. Firstly, the correlation coefficient ($R^2$) of the dosage of external carbon source and ORP value was about 0.97. Consequently, the automatic control system using ORP showed that the dosage of external carbon source was decreased by about 20% compared with a stable dosage of 75 mg/L based on the COD/N ratio of the anoxic influent.

아조벤젠기를 가진 지방산과 인지질 혼합 LB막의 전기화학적 특성 (Electrochemical Properties of Mixture Langmuir-Blogett Films of Fatty Acid containing Azobenzene and Phospholipid)

  • 박근호;최성현
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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    • pp.920-923
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    • 2004
  • We have investgated on the monolayer LB film of BASH-DMPC mixture on an ITO for the photoisomerization by light irradiation. We measured electrochemical properties by using cyclic voltammetry with a three-electrode system, An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode in $NaClO_4$ solution at a variable concentration and monolayer LB films. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate were 50, 100, 150 and 200 mV/s. As a results, LB films of 8A5H-DMPC appeared reversible process caused by the reduction-oxidation current from the cyclic voltammogram.

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Conducting Polypyrrole Doped with Hexacyanoferrate Anions: an Electrochemical and Spectroscopic Study

  • Han Junghee;Lee Seungjun;Paik Woon-kie
    • Bulletin of the Korean Chemical Society
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    • 제13권4호
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    • pp.419-425
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    • 1992
  • Conducting polypyrrole doped with iron (Ⅱ,Ⅲ) hexacyanate Fe$(CN)_6^{z-}$ ions was studied for its physical and electrochemical properties. The polymer exhibited two pairs of waves in the cyclic voltammogram, one for the reversible oxidation/reduction of the incorporated iron hexacyanate ions and the other for the near-reversible oxidation/reduction of the polypyrrole moiety. The exchange of ions incorporated in the polymer and other ions present in solutions were examined by following the decrease of the reversible redox peaks of Fe$(CN)_6^{z-}$, and by EDX analysis. The spin density of this highly conducting polymer as probed by ESR spectroscopy was extremely low compared to polypyrrole doped with common anions.