• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.266-271
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• 2006

Characteristic of partial oxidation of methane using arc-jet plasma by AC power is investigated. Arc-jet reactor used in this work is slightly modified from typical arc jet reactor so that it can make and sustain stable state of plasma. Methane conversion, selectivity of chemicals such as hydrogen and hydrocarbon materials in the product are analyzed. Parametric approach on the performance of the reactor or detail on the partial oxidation process is carried with $O_2/C$ ratio as parameter. In addition to the results, SED and arc length is changed to understand the effect of current-voltage correlation on the reforming performance and relative role of thermal process.

• Corrosion Science and Technology
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• v.5 no.4
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• pp.149-152
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• 2006

$BaTiO_3$ coatings were prepared by micro arc oxidation (MAO) method. Only $Ba(OH)_2$ was dissolved in the electrolyte and process time was less than 30 min. Commercial purity $Ba(OH)_2$ (97%) containing $BaCO_3$ as impurity was used in preparing the electrolyte. XRD showed that the coating was composed of largely $BaTiO_3$, and in some process conditions, small quantity of impurity, $BaCO_3$, was characterized in the coating layer. The quantity of $BaCO_3$ could be controlled to negligible quantity by regulating the applied voltage and duration time of the MAO process.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.80-84
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• 2014

The process of petroleum involves in a large amount of oily wastewater that contains high levels of chemical oxygen demand (COD) and toxic compounds. So they must be treated before their discharge into the receptor medium. In this paper, wet peroxide oxidation (WPO) was adopted to treat the oily wastewater. Central composite design, an experimental design for response surface methodology (RSM), was used to create a set of 31 experimental runs needed for optimizing of the operating conditions. Quadratic regression models with estimated coefficients were developed to describe the COD removals. The experimental results show that WPO could effectively reduce COD by 96.8% at the optimum conditions of temperature $290^{\circ}C$, $H_2O_2$ excess (HE) 0.8, the initial concentration of oily wastewater 3855 mg/L and reaction time 9 min. RSM could be effectively adopted to optimize the operating multifactors in complex WPO process.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.418.2-418.2
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• 2016

$Al_2O_3$ passivation layer has excellent passivation properties at p-type Si surface. This $Al_2O_3$ layer forms thin $SiO_2$ layer at the interface. There were some studies about inserting thermal oxidation process to replace naturally grown oxide during $Al_2O_3$ deposition. They showed improving passivation properties. However, thermal oxidation process has disadvantage of expensive equipment and difficult control of thin layer formation. Wet chemical oxidation has advantages of low cost and easy thin oxide formation. In this study, $Al_2O_3$/$SiO_2/Si(100)$ interface was formed by wet chemical oxidation and PA-ALD process. $SiO_2$ layer at Si wafer was formed by $HCl/H_2O_2$, $H_2SO_4/H_2O_2$ and $HNO_3$, respectively. 20nm $Al_2O_3$ layer on $SiO_2/Si$ was deposited by PA-ALD. This $Al_2O_3/SiO_2/Si(100)$ interface were characterized by capacitance-voltage characteristics and quasi-steady-state photoconductance decay method.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.32-37
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• 2019

Titanium dioxide ($TiO_2$) is a promising dielectric material in the semiconductor industry for its high dielectric constant. However, for utilization on Si substrate, $TiO_2$ film meets with a difficulty due to the large leakage currents caused by its small conduction band energy offset from Si substrate. In this study, we propose an in-situ plasma oxidation process in plasma-enhanced atomic layer deposition (PE-ALD) system to form an oxide barrier layer which can reduce the leakage currents from Si substrate to $TiO_2$ film. $TiO_2$ film depositions were followed by the plasma oxidation process using tetrakis(dimethylamino)titanium (TDMAT) as a Ti precursor. In our result, $SiO_2$ layer was successfully introduced by the plasma oxidation process and was used as a barrier layer between the Si substrate and $TiO_2$ film. Metal-oxide-semiconductor ($TiN/TiO_2/P-type$ Si substrate) capacitor with plasma oxidation barrier layer showed improved C-V and I-V characteristics compared to that without the plasma oxidation barrier layer.

• Journal of Sensor Science and Technology
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• v.25 no.4
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• pp.275-279
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• 2016

Chemical vapor deposited (CVD) polycrystalline graphene is widely used for various sensor application because of its extremely large surface-to-volume ratio. The electrical properties of CVD-graphene is significantly affected by the grain size and boundaries (GGBs), but evaluation of GGB of continuous monolayer graphene is difficult. Although several evaluation methods such as tunneling electron microscopy, confocal Raman, UV/ozone-oxidation are typically used, they still have issues in evaluation efficiency and accuracy. In this paper, we suggest an improved evaluation method for precise and simple GGB evaluation which is based on UV/ozone-oxidation and chemical etching process. Using this method, we could observe clear GGBs of CVD-graphene layers grown by different process conditions and statistically evaluate average grain sizes varying from $1.69{\sim}4.43{\mu}m$. This evaluation method can be used for analyzing the correlation between the electrical properties and grain size of CVD-graphene, which is essential for the development of graphene-based sensor devices.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.446-450
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• 2006

In order to treat the wastewater containing organic compound, pre-treatment system connected with MSP(molecular separation process) was investigated. With the aim of selecting an optimum process of Fenton's oxidation, removal efficiency of each process in the optimum reaction condition was recommended. The $Fe/H_{2}O_{2}$(ferric sulfate to hydrogen peroxide)reagent is referred to as the Fenton's regent, which produces hydroxyl radicals by the interaction of Fe with $H_{2}O_{2}$. The powerful oxidizing ability and extreme kinetic reactively of the hydroxyl radical was well established. Increasing dosage of $Fe/H_{2}O_{2}$ increased removal efficiency as molar ratio of $Fe/H_{2}O_{2}$ between 0.2 and 2.5. Optimum dosage of molar ratio was 1. The removal efficiency for reaction condition was increased as pH decreased when the molar ratio of $Fe/H_{2}O_{2}$ was 1.7. Fenton's oxidation was most efficient in the reaction time 35 min for complex wastewater. Also, coagulation aid experiments using kaolin resulted in 3% of kaolin dosage.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.634-639
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• 1996

In oder to improve the wear resistance as well as oxidation resistance at high temperature a AISI H13 steel was treated by a duplex process of calorizing followed by plasma nitriding. The surface properties of the duplex-treated AISI H13 steel was characterized and compared with those treated by single surface process of calorizing and plasma nitriding, in terms of microstruture, microhardness, wear resistance at $500^{\circ}C$, and the oxidation behaviours at $700^{\circ}C$, Duplex process on H13 steel had created duplex layer of approximately $190\mu\textrm{m}$ on the surface, and surface microhardness was measured to be above 1450Hv(0.1Kgf). There was considerable improvement of the high temperature wear resistance at $500^{\circ}C$ in the duplex-treated steel when both wear volume and weight change due to oxidation were considered. In addition the duplex-treated steel showed an improved high temperature oxidation resistance than the plasma nitrided steel at $700^{\circ}C$.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.908-917
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• 2020

Corrosion of structural materials presents a critical challenge in the use of lead-bismuth eutectic (LBE) as a nuclear coolant in an accelerator-driven system. By forming a protective layer on the steel surfaces, corrosion of steels in LBE cooled reactors can be mitigated. The amount of oxygen concentration required to create a continuous and stable oxide layer on steel surfaces is related to the oxidation process. So far, there is no oxidation experiment in fuel assemblies (FA), let alone specific oxidation detail information. This information can be, however, obtained by numerical simulation. In the present study, a new coupling method is developed to implement a coupling between the oxygen mass transfer model and the commercial computational fluid dynamics (CFD) software ANSYS-CFX. The coupling approach is verified. Using the coupling tool, we study the oxidation process of the FA and investigate the effects of different inlet parameters, such as temperature, flow rate on the mass transfer process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.726-729
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• 2010

Copper Pillar Tin Bump (CPTB) was investigated for high density chip interconnect technology development, which was prepared by electroplating and electro-less plating methods. Copper pillar tin bumps that have $100{\mu}m$ pitch were introduced with fabrication process using a KM-1250 dry film photoresist (DFR), with copper electroplating for Copper Pillar Bump (CPB) formation firstly, and then tin electro-less plating on it for control oxidation. Electric resistivity and mechanical shear strength measurements were introduced to characterize the oxidation effects and bonding process as a function of thermo-compression. Electrical resistivity increased with increasing oxidation thickness, and shear strength had maximum value with $330^{\circ}C$ and 500 N thermo-compression process. Through the simulation work, it was proved that when the CPTB decreased in its size, it was largely affected by the copper oxidation.