• Title/Summary/Keyword: selective oxidation

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Three-Dimensional Selective Oxidation Fin Channel MOSFET Based on Bulk Silicon Wafer (벌크 실리콘 기판을 이용한 삼차원 선택적 산화 방식의 핀 채널 MOSFET)

  • Cho, Young-Kyun;Nam, Jae-Won
    • Journal of Convergence for Information Technology
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    • v.11 no.11
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    • pp.159-165
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    • 2021
  • A fin channel with a fin width of 20 nm and a gradually increased source/drain extension regions are fabricated on a bulk silicon wafer by using a three-dimensional selective oxidation. The detailed process steps to fabricate the proposed fin channel are explained. We are demonstrating their preliminary characteristics and properties compared with those of the conventional fin field effect transistor device (FinFET) and the bulk FinFET device via three-dimensional device simulation. Compared to control devices, the three-dimensional selective oxidation fin channel MOSFET shows a higher linear transconductance, larger drive current, and lower series resistance with nearly the same scaling-down characteristics.

Experiments on Selective Laser Sintering of WC-Co Mixture for Rapid Metal Tooling (쾌속 금형 제작을 위한 텅스텐 카바이드와 코발트 혼합물의 선택적 레이저 소결 실험)

  • 김광희;조셉비만
    • Journal of Advanced Marine Engineering and Technology
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    • v.26 no.6
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    • pp.661-669
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    • 2002
  • Rapid tooling technique enables us to make dies and molds that produce prototype parts with the correct material at a substantially reduced cost and time. In this study, experiments on selective laser sintering of tungsten carbide-cobalt mixture were carried out to find optimal sintering conditions that will be applied to rapid metal tooling. The experiments were carried out within an air, an argon and a nitrogen atmosphere. Coupons of single layer were sintered at various laser powers, scanning speeds and scan spacings. Very severe oxidation took place within an air atmosphere. The oxidation is reduced significantly within an argon and a nitrogen atmosphere. The thickness of the sintered coupons is increased as the energy density, the laser energy Per unit scanned area, is increased. Several multi-layer sintering experiments were also carried out.

PARTIAL OXIDATION OF PROPANE ON NAFION SUPPORTED CATALYTIC MEMBRANE

  • F. Frusteri;C. Espro;F. Arena;F. Arena;E. Passalacqua;A.Patti;A. Parmaliana
    • Proceedings of the Membrane Society of Korea Conference
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    • 1999.07a
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    • pp.55-58
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    • 1999
  • Nafion supported catalytic membranes were found to be active, stable and selective in th partial oxidation of propane to oxygenates with H2O2 under mild condition. Addition of Fe2+ in liquid phase enhances the reaction rate. Reaction proceeds according to a radical mechanism based on th electrophilic activation of propane on superacid sites and subsequent reaction of the activated paraffin with OH radicals. The use of a catalytic membrane, which allow separation of the intermediate products from the liquid phase containing the oxidant, was found to be effective to perform selective partial oxidation of propane with high yields to oxygenated products.

Selective Oxidation of Cyclohexane at Low Temperature by Fe-Pd Bicatalytic Systems: $FeCl_2$-Pd/alumina System and Pd/$Fe_2O_3$ System

  • 전기원;Lingaiah Nakka;김상범;이규완
    • Bulletin of the Korean Chemical Society
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    • v.18 no.12
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    • pp.1269-1273
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    • 1997
  • The system which employs iron, palladium, molecular oxygen and hydrogen as a model mono-oxygenase, has been investigated to develop a new method for selective cyclohexane oxidation uner mild conditions. This system provides much higher yield and selectivity for the formation of cyclohexanol and cyclohexanone compared to that of the existing industrial method. When the catalytic system, FeCl2-Pd/alumina, was employed, the oxidation system required acetone as a solvent to be efficient and acidifying the solvent by a little addition of acetic acid or HCl made the system more efficient. The Pd catalyst was recyclable without a significant deactivation but the recycling of ferrous chloride showed the decrease in the activity. On the other hand, the heterogeneous catalytic system, Pd/Fe2O3 could be recovered easily and reused after drying treatment.

Characteristics of Exhaust Emission Reduction of Heavy Duty Diesel Engine by Oxidation Catalyst - Reactor Test - (산화촉매에 의한 대형디젤엔진의 배출가스 정화 특성 - Reactor 실험을 중심으로 -)

  • Jo, Gang-Rae;Kim, Yong-U;Kim, Hui-Gang
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.4
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    • pp.313-320
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    • 1998
  • The most desirable diesel oxidation catalyst (DOC) should have the properties of oxidibing CO and HC effectively at low exhaust gas temperature while minimizing the formation of sulfate at high exhaust gas temperature. Precious metals such as platinum and palladium have been known to be sufficiently active for oxidizing CO and HC and also to have high activity for the oxidation of sulfur dioxide (SO2) to sulfor trioxide (SO3). There is a need to develop a highly selective catalyst which can promote the oxidation of CO and HC efficiently, but, on the other hand, suppress the oxidation of SO2. One approach to solve this problem is to load a base metal such as vanadium in Pt-based catalyst to suppress sulfate formation. In this study, a Pt-V catalyst was prepared by impregnating platinum and vanadium onto a Ti-Si wash coated catalyst in a laboratory reactor by changing the formulations and reaction temperatures.

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Metalloporphyrin-Catalyzed Chemoselective Oxidation of Sulfides with Polyvinylpyrrolidone-Supported Hydrogen Peroxide: Simple Catalytic System for Selective Oxidation of Sulfides to Sulfoxides

  • Zakavi, Saeed;Abasi, Azam;Pourali, Ali Reza;Talebzadeh, Sadegh
    • Bulletin of the Korean Chemical Society
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    • v.33 no.1
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    • pp.35-38
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    • 2012
  • Room temperature oxidation of organic sulfides with polyvinylpyrrolidone-supported hydrogen peroxide (PVP-$H_2O_2$) in the presence of Mn(III) complexes of meso-tetraphenylporphyrin, Mn(TPP)X (X = OCN, SCN, OAc, Cl) and imidazole (ImH) leads to the highly chemoselective (ca. 90%) oxidation of sulfides to the corresponding sulfoxide. The efficiency of reaction has been shown to be influenced by different reaction parameters such as the nature of counterion (X) and solvent as well as the molar ratio of reactants. Using Mn(TPP)OCN and ImH in 1:15 molar ratio and acetone as the solvent leads to the efficient oxidation of different sulfides.