• Title/Summary/Keyword: anodic oxidation

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Studies on the anodic oxidation of some volatile organic halogen compounds(THM) (휘발성 할로겐 화합물(THM)의 양극 산화에 관한 연구)

  • Yoo, K.S.;Park, S.Y.;Yang, S.B.;Woo, S.B.
    • Analytical Science and Technology
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    • v.10 no.4
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    • pp.264-273
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    • 1997
  • Anodic oxidation reaction was applied to remove trihalomethanes in an aqueous solution. Each component was determined by using solid phase microextraction(SPME) fiber and GC-ECD. Anodic and cathodic compartments were separated in order to protect contaminants and connected by $KNO_3$-agar bridge. The calibration graphs of the 6 THM components were shown good linearlity from a few ppb up to a few hundreds ppb concentration level. Anodes such as platinum(Pt), titanium(Ti). zircornium(Zr), titanium metal coated with iridium(Ti-Ir), and glassy carbon coated with mixed valence ruthenium(mv Ru) were tried to remove the THMs at different potentials. The best result was obtained on the Ti-Ir anode applied 9 volts DC. The electrode could effectively remove almost all the THM components from the stirring solution within about 1.5 hours. The glassy carbon electrode coated with mixed valence ruthenium showed excellent removing effect at the begining, but the maximum removing level was remained at 60% probably due to the destruction of the electrode surface. The concentration of chloroform, however, tends to be increased due to the electrode reaction producing the component at the condition.

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Effects of Aluminum purity and surface condition for fabricate Nano-sized Porous using Anodic Oxidation (알루미늄 순도 및 표면처리가 나노기공의 형성에 미치는 영향)

  • Lee, Byoung-Wook;Lee, Jae-Hong;Jang, Suk-Won;Kim, Chang-Kyo
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1573-1575
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    • 2004
  • An alumina membrane with nano-sized pores was fabricated by anodic oxidation. The shape and structure of the pore on alumina membrane were changed according to the roughness of aluminum surface. The shape and structure of the nano-sized pre were investigated according to purity of aluminum substrate for the anodization process. The aluminum substrates with 99.5% and 99.999% purities were used. The aluminum substrate(99.5%) was anodized after the processes of pressing, mechanical polishing, chemical polishing, and electrochemical polishing. The nano-sized pores with the pore size of 50 - 100nm, the cell size of 20-50nm and the thickness of $10{\mu}m{\sim}45{\mu}m$ were obtained. Even though the electrochemical polishing was used for the aluminum substrate (99.999%), the same characteristics as the aluminum substrate (99.5%) was obtained. The alumina membrane prepared by anodization for 5 min using fixed voltage method shows the pore with irregular shape. The pore shape was changed to regular shape after pore widening process.

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Simulations of Optical Characteristics according to the Silicon Oxide Pattern Distance Variation using an Atomic Force Microscopy (AFM) (AFM을 이용한 나노 패턴 형성과 크기에 따른 광특성 시뮬레이션)

  • Hwang, Min-Young;Moon, Kyoung-Sook;Koo, Sang-Mo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.6
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    • pp.440-443
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    • 2010
  • We report a top-down approach based on atomic force microscopy (AFM) local anodic oxidation for the fabrication of the nano-pattern field effect transistors (FETs). AFM anodic oxidation is relatively a simple process in atmosphere at room temperature but it still can result in patterns with a high spatial resolution, and compatibility with conventional silicon CMOS process. In this work, we study nano-pattern FETs for various cross-bar distance value D, from ${\sim}0.5\;{\mu}m$ to $1\;{\mu}m$. We compare the optical characteristics of the patterned FETs and of the reference FETs based on both 2-dimensional simulation and experimental results for the wavelength from 100 nm to 900 nm. The simulated the drain current of the nano-patterned FETs shows significantly higher value incident the reference FETs from ${\sim}1.7\;{\times}\;10^{-6}A$ to ${\sim}2.3\;{\times}\;10^{-6}A$ in the infrared range. The fabricated surface texturing of photo-transistors may be applied for high-efficiency photovoltaic devices.

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.

SOI Structures Formed at Room Temperature Using FIPOS Technique (FIPOS 기술을 이용한 SOI 구조의 실온제조)

  • Choi, Kwang-Don;Lee, Jong-Byung;Sohn, Byung-Ki;Shin, Jong-Ug
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.11
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    • pp.1304-1314
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    • 1988
  • An experimental study of the influences of HF concentration, current density, reaction time and the silicon surface, on the formation and properties of porous silicon are reported. The SOI (Silicon-On-Insulator) strip lines with 100 um width are fabricated at room temperature by anodic oxidation of PSL (Porous Silicon Layers). The stress on the silicon island induced by the anodic oxidation can be avoided by the two-step PSL formation technique. At the final step of IC fabrication process, device isolation will be achieved at room temperature by this method.

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