• Title/Summary/Keyword: Oxidation/Reduction

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NOx Removal of NH3-SCR Catalysts with Operating Conditions (공정조건에 따른 NH3-SCR용 촉매의 질소산화물 제거특성)

  • Park, Kwang Hee;Cha, Wang Seog
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5610-5614
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    • 2012
  • Performance of catalyst was studied with various operating conditions for selective catalytic reduction of $NO_x$ with $NH_3$. It is confirmed that catalysts containing Mn and Cu have a good efficiency in the usage of oxygen by the $H_2$-TPR analysis. In the case of catalyst #1, $NO_x$ conversion was decrease with the increase of reaction temperature. But in the case of catalyst #2, $NO_x$ conversion was increased and then remained constant with the increase of reaction temperature. This phenomenon is due to the difference of the $NH_3$ oxidation of both catalysts.

A Study of the Curricular Articulation of Oxidation-Reduction in the Textbooks from Middle School to College (중등 및 대학 교재 중 산화-환원반응에 대한 연계성 연구)

  • Kim, Hyo-Kyum;Moon, Seong-Bae
    • Journal of the Korean Chemical Society
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    • v.44 no.2
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    • pp.145-156
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    • 2000
  • The content of oxidation-reduction in the chemistry textbooks from middle school to college was analyzed about the effective connection of curricular articulation. The classification was divided from five groups of 'first concept', 'same concept', 'overlap', 'development', and 'gap'. As a results, there was a deep big gap from middle school to high school and the effectiveness from high school to college was quite acceptable. Finally, the flow map, consisted of each concept between the school unit, was suggested.

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Physical Properties and Dyeability of Fine Count Wool Yarns and Its Fabrics by Drawing Process of Fineness Control (섬도제어 연신공정에 의한 세섬화 양모 소재의 물성 연구)

  • Kim, Mikyung;Jeon, Byeongdae;Jeong, Jaeseok
    • Textile Coloration and Finishing
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    • v.28 no.4
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    • pp.253-270
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    • 2016
  • In the wool textile industry, the necessity for technology development has been steadily raised to create improved fineness and yarn count of existing wool yarns with thick fineness for ensuring higher quality grades of wool yarn. Recently, through controlling fineness of wool yarn for making finer wool in relation with environmentally-friendly and high-sensitivity trend, a differentiated continuous drawing process where the quality of wool can be artificially manipulated has been suggested in the latest textile industry. This study investigated the basic conditions during the continuous drawing process which enable to manufacture wool yarn with fine count by controlling reducing agent treatment, physical drawing and drying after reducing agent treatment, and oxidizing agent post-treatment conditions. Furthermore, this study reviewed the drawing effects by applying the basic conditions for reduction and oxidation reaction in the drawing processes of wool/cashmere, wool/silk, wool/polyester blended yarns as well as such wool yarns. Also, in order to review the practicability, this study examined the physical properties and dyeability of drawn wool yarn applied textile materials in comparison with normal wool yarn applied textile materials.

Evaluation of Electrolyzed Oxidizing Water as a Control Agent of Cucumber Powdery Mildew

  • Lee, Yong-Hwan;Cha, Kwang-Hong;Ko, Sook-Ju;Park, In-Jin;Park, Boung-In;Seong, Ki-Young
    • The Plant Pathology Journal
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    • v.16 no.4
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    • pp.206-210
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    • 2000
  • The effect of the electrolyzed oxidizing water on Sphaerotheca fuliginea was investigated with germination and sporulation of the fungal conidia. The sporulation was inhibited by the electrolyzed oxidizing water of pH 2.5, 3.5, and 4.5, but was not inhibited by the distilled water adjusted pH with 1N-HCL solution. However, the electrolyzed oxidizing water did not affect conidial germination. The oxidation-reduction potential at pH 2.5 and pH 3.5 of electrolyzed oxidizing water were 1130 mV and 1060 mV, respectively, but those of distilled water adjusted with HCL solution were 550 mV and 490 mV, respectively. When the electrolyzed oxidizing water of ORP over 1100 mV was sprayed on cucumplanting, the disease severities of powdery mildew were about 8.5% and 19.2%, respectively. Disease severity of a standard control (triflumizole 30% WP, $500\textrm{mg}\textrm{/L}$) was about 3.0%, while that of plants without electrolyzed oxidizing water was to 45.8%.

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A Study on the removal of Metallic Impurities on Si-wafer using Electrolyzed Water (전해수를 이용한 실리콘 웨이퍼 표면의 금속오염 제거)

  • Yoon, Hyo-Seob;Ryoo, Kun-Kul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.04b
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    • pp.1-5
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    • 2000
  • As the semiconductor devices are miniaturized, the number of the unit cleaning processes increases. In order to processes by conventional RCA cleaning process, the consumption of volume of liquid chemical and DI water became huge. Therefore, the problem of environmental issues are evolved by the increased consumption of chemicals. To resolve this matter, an advanced cleaning process by Electrolyzed Water was studied in this work. The electrolyzed water was made by an electrolysis equipment which was composed of three chambers of anode, cathode, and middle chambers. In the case of electrolyzed water with electrolytes in the middle chamber, oxidatively acidic water of anode and reductively alkaline water of cathode were obtained. The oxidation/reduction potentials and pH of anode water and cathode water were measured to be +l000mV and 4.8, and -530mV and 6.3, respectively. The Si-wafers contaminated with metallic impurities were cleaning with the electrolyzed water. To analysis the amounts of metallic impurities on Si-water surfaces, ICP-MS(Inductively Coupled Plasma-Mass spectrometer) was introduced. From results of ICP-MS measurements, it was concluded that the ability of electrolyzed water was equivalent to that of the conventional RCA cleaning.

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Performances of Metallic (sole, composite) and Non-Metallic Anodes to Harness Power in Sediment Microbial Fuel Cells

  • Haque, Niamul;Cho, Daechul;Kwon, Sunghyun
    • Environmental Engineering Research
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    • v.19 no.4
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    • pp.363-367
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    • 2014
  • One chambered sediment microbial fuel cell (SMFC) was equipped with Fe, brass (Cu/Zn), Fe/Zn, Cu, Cu/carbon cloth and graphite felt anode. Graphite felt was used as common cathode. The SMFC was membrane-less and mediator-less as well. Order of anodic performance on the basis of power density was Fe/Zn ($6.90Wm^{-2}$) > Fe ($6.03Wm^{-2}$) > Cu/carbon cloth ($2.13Wm^{-2}$) > Cu ($1.13Wm^{-2}$) > brass ($Cu/Zn=0.24Wm^{-2}$) > graphite felt ($0.10Wm^{-2}$). Fe/Zn composite anode have twisted 6.73% more power than Fe alone, Cu/carbon cloth boosted power production by 65%, and brass (Cu/Zn) produced 65% less power than Cu alone. Graphite felt have shown the lowest electricity generation because of its poor galvanic potential. The estuarine sediment served as supplier of oxidants or electron producing microbial flora, which evoked electrons via a complicated direct microbial electron transfer mechanism or making biofilm, respectively. Oxidation reduction was kept to be stationary over time except at the very initial period (mostly for sediment positioning) at anodes. Based on these findings, cost effective and efficient anodic material can be suggested for better SMFC configurations and stimulate towards practical value and application.

A Study of Prevention of Pipe Scale with Cu-Zn Metal Fiber (Cu-Zn Metal Fiber를 이용한 배관 스케일 방지에 관한 연구)

  • Lee, Sang-Ho;Kim, Jong-Hwa;Song, Ju-Yeong
    • Journal of the Korean Applied Science and Technology
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    • v.27 no.1
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    • pp.70-75
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    • 2010
  • Scale generation in the inside of a pipe IS restricted by reduction and oxidation(REDOX) reaction of alloyed metal of Cu-Zn. To measure the scale generating rate in the 1.67 mm of inside diameter of stainless steel tube, 300 ppm of $CaCO_3$ solution is circulated in the REDOX reactor and stainless steel tube in the order. In the case of $CaCO_3$ solution treated by REDOX reactor, flowing is maintained without plugging in the stainless steel tube, and the concentration of Cu and Zn in the circulating solution showed less than 1 ppm, which is equal to that of untreated by REDOX reactor. The crystal type of $CaCO_3$ generated by crystalline nucleus of Cu or Zn, mostly showed aragonite type.

Studies on the Cosmetic Analysis based upon Oxidation Reduction Reactions (산화환원 반응을 이용한 화장품 분석에 관한 연구)

  • Kim, Young-So;Kim, Boo-Min;Park, Sang-Chul;Park, Jeong-Eun;Jeong, Hye-Jin;Chang, Ih-Seop
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.33 no.1 s.60
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    • pp.11-15
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    • 2007
  • Oxidation/reduction titrations are important quantitative procedures for many chemicals. Several widely used analytical methods for cosmetic ingredients are based on the redox reactions. In this article, we summarized basic theories of redox titration and applications. Determination of unsaturation properties based on iodine or bromine number, quantitation of hydrogen peroxide or peroxide materials in several cosmetic ingredients and measurement of titanium dioxide, widely used sunscreen agent, in cosmetics are discussed here.

Evaluate of Electrochemical Characteristics in Electrolyzed Reduced Water

  • Park, Sung-Ho;Yun, Su-Jin;Kim, Jeong-Sik;Shin, Hyun-Su;Park, Soo-Gil
    • Journal of Electrochemical Science and Technology
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    • v.2 no.2
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    • pp.85-90
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    • 2011
  • Active oxygen species or free radicals are considered to cause extensive oxidative damage to biological macromolecules, which brings about a variety of diseases as well as aging. Electrolyzed reduced water(ERW) has been regarded as a ideal antioxidative agent in recent years. ERW is produced by passing a diluted salt solution through an electrolytic cell, within which the anode and cathode are separated by membrane. It can be produced reactive materials in ERW near the cathode during the electrolysis of water. ERW have the following advantages over other traditional cleaning agents: effective antioxidative agent, easy preparation, inexpensive, and environmentally friendly. The main advantage of ERW is its safety and antioxidative effect. ERW with strong reducing potential can be used to remove dirt and grease from items such as cutting boards and other kitchen utensils. The primary aim of this study is the activation mechanism of oxidation reduction potentials, ion conductivity, pH, and electrochemical properties with reactive materials in ERW.

Natural Gas Combustion Characteristics of Mass Produced Oxygen Carrier Particles for Chemical-looping Combustor in a Batch Type Fluidized Bed Reactor (회분식 유동층 반응기에서 매체순환식 가스연소기용 대량생산 산소공여입자들의 천연가스 연소특성)

  • Ryu, Ho-Jung;Kim, Kyung-Su;Park, Yeong-Seong;Park, Moon-Hee
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.2
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    • pp.151-160
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    • 2009
  • Natural gas combustion characteristics of mass produced oxygen carrier particles were investigated in a batch type bubbling fluidized bed reactor. Five particles, NiO/bentonite, OCN601-650, OCN702-1100, OCN703-950, OCN703-1100 were used as oxygen carrier particles. Natural gas and air were used as reactants for reduction and oxidation, respectively. During reduction reaction, high fuel conversion and high $CO_2$ selectivity were achieved for most of oxygen carriers. During oxidation, NO emission was very low. These results indicate that inherent $CO_2$ separation and low NOx combustion are feasible for the natural gas fueled chemical-looping combustion system. Among the five oxygen carriers, OCN703-1100 particle was selected as the best candidate for demonstration of long-term operation in large-scale chemical-looping combustor from the viewpoints of fuel conversion, $CO_2$ selectivity, $CH_4$ concentration, and CO concentration.