• Title, Summary, Keyword: Oxides

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Modeling of Dielectric Barrier Discharge Plasma Process for the Removal of Nitric Oxide (유전체 방전 플라즈마 공정에 의한 일산화질소 제거 공정 모델링)

  • Mok, Young-Sun
    • Journal of the Korean Society of Industry Convergence
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    • v.6 no.4
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    • pp.277-289
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    • 2003
  • This study proposes a mathematical model to characterize the removal of nitrogen oxides in a dielectric barrier discharge plasma process. As well as the reactions between nitrogen oxides, water vapor, oxygen and nitrogen, the model takes into account the effect of ethylene often used as a chemical additive to reduce the power consumption of the process on the removal of nitrogen oxides. Since the concentrations of the radicals concerned in the main reactions including O, OH, H and N should be calculated to predict the removal efficiency of nitrogen oxides, they were theoretically derived. The parameters affecting the removal of nitrogen oxides, such as initial concentration, discharge power, humidity, and ethylene concentration were experimentally evaluated, which were compared with the calculated results to verify the validity of the model proposed. The predicted concentrations of several byproducts formed in this process were also presented and discussed. The effects of several parameters mentioned above on the removal of nitrogen oxides were reasonable described by the proposed model.

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ELECTRICAL CHARACTERISTICS OF THIN DIELECTRIC FILMS PREPARED BY RAPID THERMAL PROCESS (RAPID THERAL PROCESS를 응용한 THIN DIELECTRIC FILM의 전기적 특성에 관한 연구.)

  • Lee, Ang-Goo;Park, Seong-Sik;Choi, Jin-Seog;Rhieu, Ji-Hyo
    • Proceedings of the KIEE Conference
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    • pp.542-545
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    • 1987
  • THE ELECTRICAL CHARACTERISTICS Of RAPID THERMAL OXIDES AND NITRIDED OXIDES HAVE BEEN INVESTIGATED. R.T.OXIDE FILMS HAVE BEEN PREPARED BY ONLY R.T. OXIDATION OR R.T.OXIDATION AND SUBSEQUENT R.T.ANNEAL. NITRIDED OXIDE FILMS HAVE BEEN PREPARED BY R.T.OXIDATION AND SUBSEQUENT R.T.NITRIDATION.AND CONVENTIONAL OXIDES ALSO HAVE BEEN PREPARED TO COMPARE WITH R.T.P OXIDES. R.T.ANNEALED OXIDES SHOW EXCELLENT BREAKDOWN FIELD. LEAKAGE CURRENT AND TDDB CHARACTERISTICS. ALSO, CAPACITANCE Of R.T NITRIDED OXIDES ARE SUPERIOR BY 10% TO CONVENTIONAL OXIDES, BUT TDDB CHARACTERISTIC ARE POORER THAN OXIDE FILMS.

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Characterizations of nitrided gate oxides by fowler-nordheim tunneling electron injection (Fowler-nordheim 터널링 전자주입에 의한 질화 게이트 산화막의 특성 분석)

  • 장성수;문성근;노관종;노용한;이칠기
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.7
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    • pp.79-87
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    • 1998
  • Nitrided oxides which have been investigated as alternative gate oxide for metal-oxide-semiconductor field effect devices were grown by two-step process using N$_{2}$O gas, and were chaacterized via a fowler-nordheim tunneling(FNT) electron injection technique. Electrical characteristics of nitrided gate oxides were superior to that of control oxides.Further, the FNT electron injection into the nitrided gate oxides reveals that gate oxides degrade more both if electrons were foreced to inject from the gate metal and if thicker nitrided gate oxides were used in the thickness range of 90~130.angs.. Models are suggested to explain these phenomena.

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Characterization of the Biogenic Manganese Oxides Produced by Pseudomonas putida strain MnB1

  • Jiang, Shaofeng;Kim, Do-Gun;Kim, Jeong-Hyun;Ko, Seok-Oh
    • Environmental Engineering Research
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    • v.15 no.4
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    • pp.183-190
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    • 2010
  • Biogenic Mn oxides are expected to have great potential in the control of water pollution due to their high catalytic activity, although information on biological Mn oxidation is not currently sufficient. In this study, the growth of a Mn oxidizing microorganism, Pseudomonas putida MnB1, was examined, with the Mn oxides formed by this strain characterized. The growth of P. putida MnB1 was not significantly influenced by Mn(II), but showed a slightly decreased growth rate in the presence of Pb(II) and EE2, indicating their insignificant adsorption onto the cell surface. Mn oxides were formed by P. putida MnB1, but the liquid growth medium and resulting biogenic solids were poorly crystalline, nano-sized particles. Biogenic Mn oxidation by P. putida MnB1 followed Michaelis-Menten kinetics, with stoichiometric amounts of Mn oxides formed, which corresponded with the initial Mn(II) concentration. However, the formation of Mn oxides was inhibited at high initial Mn(II) concentration, suggesting mass transfer obstruction of Mn(II) due to the accumulation of Mn oxides on the extracellular layer. Mn oxidation by P. putida MnB1 was very sensitive to pH and temperature, showing sharp decreases in the Mn oxidation rates outside of the optimum ranges, i.e. pH 7.43-8.22 and around 20-$26^{\circ}C$.

Characteristics of Copper and Cadmium Partitioning in Aquatic Sediment (수계내 저질에 대한 구리 및 카드뮴의 분배 특성)

  • 이군자;박청길
    • Journal of Environmental Science International
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    • v.1 no.2
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    • pp.71-79
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    • 1992
  • Selective extraction procedure has been used to quantify copper and cadmium In association with the various phases of aquatic sediment such as exchangeable/adsorbed, carbonate, manganese oxides, organic matter and iron oxides. Changes of pH influenced on the partitioning of copper in carbonate and exchangeable/ad- sorbed phases and of cadmium in carbonate phase of aquatic sediment. Addition of NTA and EDTA, copper and cadmium associated with carbonate phase were released from sediment to water. Total partitioning coefficient was 8.361 for copper and 0.497 for cadmium. The relative binding strengths of copper and cadmium to each solid phase can be ranked by using the partitioning coefficints. For copper it was observed that carbonate > organic matter > exchangeable/adsorbed > manganese oxides > iron oxides and for cadmiunm it was observed that exchangeable/adsorbed > carbonate > manganese oxides > organic matter > iron oxides.

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Analyses of Thermodynamic Vaporization Behaviour and Voloxidaion Conditions for Metal Oxides (금속산화물의 열역학적 휘발 거동 및 휘발 산화 공정의 조건 분석)

  • Lee, Young Woo;Park, So Young;Park, Byung Heung
    • Journal of Institute of Convergence Technology
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    • v.3 no.2
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    • pp.7-10
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    • 2013
  • Metal oxides are known as stable materials during a thermal treatment. However, some oxides are readily evaporated at high temperatures. A voloxidation process is a head-end process for a pyroprocessing dealing with spent nuclear fuels (SF). In SFs, fission productions are in the form of oxides and some of them would be evaporated during the voloxidation process. Therefore, it is of importance to analyse the vapor pressures of metal oxides so that the material flows throughout the pyroprocessing could be estimated. In this work, vapor pressures of relevant metal oxides were calculated and presented to draw a baseline on the material flow of the pyroprocessing.

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Reaction Route to the Crystallization of Copper Oxides

  • Chen, Kunfeng;Xue, Dongfeng
    • Applied Science and Convergence Technology
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    • v.23 no.1
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    • pp.14-26
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    • 2014
  • Copper is an important component from coin metal to electronic wire, integrated circuit, and to lithium battery. Copper oxides, mainly including $Cu_2O$ and CuO, are important semiconductors for the wide applications in solar cell, catalysis, lithium-ion battery, and sensor. Due to their low cost, low toxicity, and easy synthesis, copper oxides have received much research interest in recent year. Herein, we review the crystallization of copper oxides by designing various chemical reaction routes, for example, the synthesis of $Cu_2O$ by reduction route, the oxidation of copper to $Cu_2O$ or CuO, the chemical transformation of $Cu_2O$ to CuO, the chemical precipitation of CuO. In the designed reaction system, ligands, pH, inorganic ions, temperature were used to control both chemical reactions and the crystallization processes, which finally determined the phases, morphologies and sizes of copper oxides. Furthermore, copper oxides with different structures as electrode materials for lithium-ion batteries were also reviewed. This review presents a simple route to study the reaction-crystallization-performance relationship of Cu-based materials, which can be extended to other inorganic oxides.

Defect Structure, Nonstoichiometry and Nonstoichiometry Relaxation of Complex Oxides

  • Yoo, Han-Ill
    • Journal of the Korean Ceramic Society
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    • v.44 no.12
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    • pp.660-682
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    • 2007
  • An SOFC consists of all ceramic complex oxides each with different electrochemical-property requirements. These requirements, in principle, can be made met to a great extent by controlling or tailoring the defect structure of the oxide. This paper reviews the defect structure, nonstoichiometry as a measure of the total defect concentration, and the defect relaxation kinetics of complex oxides that are currently involved in a variety of growing applications today.

Study on Stabilization of Arsenic in Soil through in situ Formation of Amorphous Fe Oxides and use of X-ray Absorption Spectroscopy (비결정질철산화물 원위치 형성을 통한 비소오염토양 안정화 및 X선 분광분석법의 활용에 대한 연구)

  • Park, Jinhee;Chung, Hyeonyong;Kim, Sang Hyun;An, Jinsung;Nam, Kyoungphile
    • Journal of Soil and Groundwater Environment
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    • v.25 no.2
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    • pp.9-15
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    • 2020
  • This study was conducted to investigate the in situ formation of amorphous Fe oxides as a stabilization technology in As-contaminated soil. After addition of ferric nitrate and the neutralizing agent, most of extractable fractions of As in soil (i.e., SO42- and PO43--extractable As) was converted into As bound to amorphous Fe oxides. In addition, results of solubility bioavailability research consortium (SBRC) test indicated that a significant amount of As in untreated soil changed to a non-bioaccessible form after stabilization. The reason was attributed to the newly formed amorphous Fe oxides in the stabilized soil, which was confirmed by linear combination of fitting (LCF) using X-ray absorption spectroscopy (XAS) analysis. Interestingly, after five months of aging of the stabilized soil, ferrihydrite and schwertmannite newly formed in the soil were transformed to crystalline Fe oxides such as goethite, and further decrease in SBRC extractable fraction of As was observed. The results suggest that co-precipitated As with amorphous Fe oxides can be further immobilized with time, due to the crystallization of amorphous Fe oxides.

Performance Test of Ceramic Filter Collector for the heavy-oil boiler for Concurrent treatment Dust and Nitrogen Oxides (분진 및 질소산화물 동시처리를 위한 1톤 중유 보일러용 세라믹 필터 집진기의 성능실험)

  • Jung, Wan-Bo;Cho, Jung-Sick
    • Journal of the Korean Society of Industry Convergence
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    • v.21 no.6
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    • pp.355-360
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    • 2018
  • The product developed in this study is a ceramic catalyst filter for 1 ton heavy-oil boiler that can simultaneously process dust and nitrogen oxides. This has been developed for simultaneous processing of nitrogen oxides and dust at high efficiency of hot exhaust gas (approximately $300^{\circ}C$) generated after burning 1 ton heavy oil boiler. Ceramic catalytic filters for 1 tonne heavy-duty glass display are technologies that remove 90% of dust and 85% or more of nitrogen oxides. This is an improved new technology to integrate exhaust ventilation and desiccation devices into one, thereby reducing the production process and improving the economy. To this end, the performance test of the catalytic filter for heavy oil boilers was carried out, and the durability of the PLC circuit was constructed.