• 제목/요약/키워드: metal ion addition

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Characterization of photonic quantum ring devices manufactured using wet etching process (습식 식각 공정을 이용하여 제작된 광양자테 소자의 특성 분석)

  • Kim, Kyoung-Bo;Lee, Jongpil;Kim, Moojin
    • Journal of Convergence for Information Technology
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    • v.10 no.6
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    • pp.28-34
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    • 2020
  • A structure in which GaAs and AlGaAs epilayers are formed with a metal organic chemical vapor deposition equipment on a GaAs wafer similar to the structure of making a vertical cavity surface emitting laser is used. Photonic Quantum Ring (PQR) devices that are naturally generated by 3D resonance are manufactured by chemically assisted ion beam etching technology, which is a dry etching method. A new technology that can be fabricated has been studied, and as a result, the possibility of wet etching of a solution containing phosphoric acid, hydrogen peroxide and methanol was investigated, and the device fabrication by applying this method are also discussed. In addition, the spectrum of the fabricated optical device was measured, and the results were theoretically analyzed and compared with the wavelength value obtained by the measurement. It is expected that the PQR device will be able to model cells in a three-dimensional shape or be applied to the display field.

Effect of Metal ion on Rancidity of Crude Rapeseed Oil (비정제 유채유의 산패에 미치는 금속이온의 영향)

  • Kim, Youn-Soon;Kim, Youn-Su;Nam, Hyung-Gun;Seo, Gwang-Yeob
    • Journal of environmental and Sanitary engineering
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    • v.24 no.1
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    • pp.33-39
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    • 2009
  • In order to investigate effect of metal ion and antioxidant on rancidity of crude rapeseed oil (CRO), $Fe^{2+}$, $Cu^{2+}$, $Co^{2+}$, $Ni^{2+}$, $Cr^{2+}$, $Sn^{2+}$, $Mn^{2+}$, $Zn^{2+}$, and antioxidants including BHA, Vitamin C, and Tocopherol were used. The specific gravity and refractive index of CRO were $0.92g/cm^3$ and 1.45, respectively. The chromaticities of light, red, and yellow in CRO were 88.6 and 98.7, respectively. Among various fatty acids, Oleic acid (C18:1) concentration was highest, 62.3% and Linoleic acid (C18:2) concentration was 19.16%. In the case of Linolenic acid (C18:3) and Palmitic acid (C16:0), they were 9.88 and 5.2%, respectively. The concentrations of unsaturated fatty acids and saturated fatty acid were 92.2 and 7.8%, respectively. The degree of expediting rancidity of CRO was an order of $Fe^{2+}$> $Cu^{2+}$> $Cr^{2+}$> $Zn^{2+}$> $Ni^{2+}$> $Al^{2+}$> $Mn^{2+}$> $Mn^{2+}$> $Sn^{2+}$> $Co^{2+}$> $Li^{2+}$. Especially, when $Cu^{2+}$ and $Fe^{2+}$ was used, the peroxide value concentration was about 4.0 fold higher than non addition of them. The inhibition effect of rancidity of CRO using antioxidant with $Cu^{2+}$ and $Fe^{2+}$ was an order of BHA> Vitamin C> Tocopherol.

High-temperature electrochemical corrosion behavior of SA106 Grade B carbon steel with corrosion inhibitors in HyBRID solution

  • Sung-Wook Kim;Sang-Yoon Park;Chang-Hyun Roh;Sun-Byeong Kim
    • Nuclear Engineering and Technology
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    • v.55 no.6
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    • pp.2256-2262
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    • 2023
  • The electrochemical corrosion behaviors of SA106 Grade B (SA106B) carbon steel in H2SO44-N2H4 and H2SO4-N2H4-CuSO4 solutions at 95 ℃ have been investigated with the addition of commercial corrosion inhibitors (CI#30 and No. 570S), to determine the stability of SA106B in the hydrazine-based reductive metal ion decontamination (HyBRID) process. The potentiodynamic polarization experiment revealed that the corrosion inhibitors were capable of lowering the corrosion rate of SA106B in H2SO4-N2H4 solution. It was found that the corrosion inhibitors induced formation of fixed surface layer on the carbon steel upon the corrosion. This corrosion inhibition performance was reduced in the presence of CuSO4 in the solution owing to the chemical reactions between organic compounds in the corrosion inhibitors and CuSO4. CI#30 showed a better corrosion inhibition effect in the H2SO4-N2H4-CuSO4 solution. Although the corrosion inhibitors can provide better stability to SA106B in the HyBRID solution, their application should be carefully considered because it may result in reduced decontamination performance and increased secondary waste generation.

Effects of the Young Branch of Prunus persica Methanol Extracts and Solvent Fractions on ROS, RNS and Oxidized Low-Density Lipoprotein (도지(桃枝) 메탄올 추출물과 용매별 분획물이 활성산소종, 활성질소종 및 저밀도 지단백의 산화에 미치는 효과)

  • Moon, Jin Young;Park, Ju Yeon
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.27 no.2
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    • pp.189-195
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    • 2013
  • This study was designed to analyze the effects of methanol extracts and solvent fractions of the young branch of Prunus persica on scavenging activity of ROS, RNS and inhibiting activity of oxidative modification in human LDL induced by copper ion or free radical generator. The scavenging capacities of the fractions on DPPH radical, superoxide radical, nitric oxide and peroxynitrite were exhibited the highest in ethylacetate fraction, followed by butanol fraction. In the copper-induced LDL oxidative modification system, the highest antioxidant activity was revealed in ethylacetate fraction, and butanol fraction exhibited a similar activity. However, solvent fractions of the young branch of Prunus persica showed a relatively low antioxidant activity in the AAPH-mediated LDL oxidation. In addition, ethylacetate and butanol fractions also inhibited the copper-mediated LDL oxidation in the REM assay, which was comparable to that of the positive controls, including EDTA, ascorbic acid and BHT. Futhermore, a content of total phenolics in these two fractions was higher than that of the other fractions. These results indicated that ethylacetate and butanol fractions of the young branch of Prunus persica were useful for the prevention of the free radical- or metal ion-induced oxidative damages.

Experimental Simulation of Iron Oxide Formation on Low Alloy Steel Evaporator Tubes for Power Plant in the Presence of Iron Ions

  • Choi, Mi-Hwa;Rhee, Choong-Kyun
    • Bulletin of the Korean Chemical Society
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    • v.30 no.11
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    • pp.2577-2583
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    • 2009
  • Presented are the formation of iron oxide layers on evaporator tubes in an actual fossil power plant operated under all volatile treatment (AVT) condition and an experimental simulation of iron oxide formation in the presence of ferrous and ferric ions. After actual operations for 12781 and 36326 hr in the power plant, two iron oxide layers of magnetite on the evaporator tubes were found: a continuous inner layer and a porous outer layer. The experimental simulation (i.e., artificial corrosion in the presence of ferrous and ferric ions at 100 ppm level for 100 hr) reveals that ferrous ions turn the continuous inner oxide layer on tube metal to cracks and pores, while ferric ions facilitate the production of porous outer oxide layer consisting of large crystallites. Based on a comparison of the oxide layers produced in the experimental simulation with those observed on the actually used tubes, we propose possible routes for oxid layer formation schematically. In addition, the limits of the proposed corrosion routes are discussed in detail.

Recovery of cesium ions from seawater using a porous silica-based ionic liquid impregnated adsorbent

  • Wu, Hao;Kudo, Tatsuya;Kim, Seong-Yun;Miwa, Misako;Matsuyama, Shigeo
    • Nuclear Engineering and Technology
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    • v.54 no.5
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    • pp.1597-1605
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    • 2022
  • A porous silica-based adsorbent was prepared by impregnating the pores of a silica support with the extractant 1,3-[(2,4-diethylheptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14) and an additive agent 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C2mim + NTf-2) as the materials to remove cesium(I) (Cs+) ions from seawater. The as-prepared adsorbent showed excellent adsorption performance toward Cs+ ions, with adsorption equilibrium reached within 2 h and an adsorption amount of 0.196 mmol/g observed. The solution pH, temperature, and the presence of coexisting metal ions were found to have almost no effect on Cs+ adsorption. The adsorption mechanism was considered to proceed via ion exchange between Cs+ and C2mim+. In addition, the particle-induced X-ray emission analysis results further clarified that the adsorbed Cs+ ion species on the adsorbent was in the form of both CsCl and CsBr.

OPTIMIZATION OF CULTURE CONDITIONS FOR PRODUCTION OF PNEUMOCOCCAL CAPSULAR POLYSACCHARIDE TYPE I

  • Kim, S.N.;K.K. Min;Kim, S.H.;Park, I.H.;Lee, S.H.;S.N. Pyo;D.K. Rhee
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1996.04a
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    • pp.186-186
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    • 1996
  • Streptococcus pneumoniae (pneumococcus), the most common cause of bacterial pneumonia, has an ample polysaccharide(PS) capsule that is highly antigenic and is the source of PS vaccine. This investigation was undertaken to optimize the culture conditions for the production of capsular PS by type 1 pneumococcus. Among several culture media, brain heart infusion (BHI) and Casitone based media were found to support luxuriant growth of pneumococcus type 1 at the same level. Because BHI medium is rather expensive and more complex than the Casitone based media, the Casitone based media was used to study optimization of the culture condition. The phase of growth which accomodated maximum PS production was logarithmic phase. Concentrations of glucose greater than 0.2% did not enhance growth or PS production. Substitution of nitrogen sources with other resources or supplemention of various concentrations of metal ion (with the exception of calcium ion) had adverse effects on growth and PS production. On the other hand, low level aeration was beneficial for increased PS production. Addition of 3 mg/I concentration of methionine, phenylalanine, and threonine were found to enhance growth and PS production. The synergistic effect of all the favorable conditions observed in pneumococcal growth assays provided a two-fold cumulative increase in capsular PS production.

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Effect of Metal Loading Methods on the Catalytic Activity for N2O/NO Simultaneous Reduction over Fe/BEA Zeolite Catalyst (Fe/BEA 제올라이트 촉매의 N2O/NO 동시 환원 반응에서 금속 담지 방법이 촉매 활성에 미치는 영향)

  • Jeon, Min-Wook;Lee, Seung-Jae;Ryu, In-Soo;Moon, Seung-Hyun;Rhee, Young Woo;Jeon, Sang Goo
    • Korean Chemical Engineering Research
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    • v.55 no.5
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    • pp.679-684
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    • 2017
  • The influence of catalytic activity on Fe loading methods over Fe/BEA zeolite catalyst in the simultaneous reduction of $N_2O/NO$ has been studied. The Fe/BEA zeolite catalysts were prepared by ion exchange and impregnation. Catalytic tests were carried out in the selective catalytic reduction using ammonia as a reductant to identify the activity of prepared catalysts. The results show that the ion exchanged catalyst exhibited higher NO and $N_2O$ conversions than the impregnated catalysts did. To investigate the difference in catalytic activity, we performed various analyses such as XRD, $H_2-TPR$, $O_2-TPD$ and XPS. It is considered that the increase in the activity of the ion exchange catalyst is due to improved reducibility and increased oxygen desorption rate. In addition, the ion exchange catalyst was found through the XPS analysis that $Fe^{2+}$, which is related to the catalytic activity, is formed about 1.6 times more than the impregnated catalyst.

Leaching of Valuable Metals from NCM Cathode Active Materials in Spent Lithium-Ion Battery by Malic acid (폐리튬이온전지 NCM 양극활물질로부터 말릭산을 이용한 유가금속의 침출)

  • Son, Seong Ho;Kim, Jin Hwa;Kim, Hyun-Jong;Kim, Sun Jung;Lee, Man Seung
    • Resources Recycling
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    • v.23 no.4
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    • pp.21-29
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    • 2014
  • Nickel, cobalt and manganese-based(NCM, $Li(Ni_xCo_yMn_z)O_2$) cathode active materials of spent lithium-ion batteries contained valuable metals such as cobalt(15 ~ 20%), nickel(25 ~ 30%), manganese(10 ~ 15%) and lithium(5 ~ 10%). It was investigated the eco-friendly leaching process for the recovery of valuable metal from spent lithium-ion battery NCM cathode active materials by DL-malic acid($C_4H_5O_6$) as an organic leachant in this research. The experiments were carried out to optimize the process parameters for the recovery of cobalt, nickel and lithium by varying the concentration of lixivant, reductant concentration, solid/liquid ratio and temperature. The leaching solution was analyzed using ICP-OES(Inductively Coupled Plasma Optic Emission Spectrometer). Cathode active materials of 5 wt. % were introduced into the leaching solution which was 2 M DL-malic acid in addition of 5 vol. % $H_2O_2$ at $80^{\circ}C$ and it resulted in the recovery of 99.10% cobalt, 99.80% nickel and 99.75% lithium in 120 min. $H_2O_2$ in DL-malic acid solution acts as an effective reducing agents, which enhance the leaching of metals.

Effects of Doping Concentration of Polycrystalline Silicon Gate Layer on Reliability Characteristics in MOSFET's (MOSFET에서 다결정 실리콘 게이트 막의 도핑 농도가 신뢰성에 미치는 영향)

  • Park, Keun-Hyung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.2
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    • pp.74-79
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    • 2018
  • In this report, the results of a systematic study on the effects of polycrystalline silicon gate depletion on the reliability characteristics of metal-oxide semiconductor field-effect transistor (MOSFET) devices were discussed. The devices were fabricated using standard complimentary metal-oxide semiconductor (CMOS) processes, wherein phosphorus ion implantation with implant doses varying from $10^{13}$ to $5{\times}10^{15}cm^{-2}$ was performed to dope the polycrystalline silicon gate layer. For implant doses of $10^{14}/cm^2$ or less, the threshold voltage was increased with the formation of a depletion layer in the polycrystalline silicon gate layer. The gate-depletion effect was more pronounced for shorter channel lengths, like the narrow-width effect, which indicated that the gate-depletion effect could be used to solve the short-channel effect. In addition, the hot-carrier effects were significantly reduced for implant doses of $10^{14}/cm^2$ or less, which was attributed to the decreased gate current under the gate-depletion effects.