• Clean Technology
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• v.12 no.3
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• pp.138-144
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• 2006

Conversion of methane to synthesis gas in a capacitive rf plasma at low pressure was experimentally studied. In this plasma, electrons which had sufficient energy-level collided with the molecules of methane or oxygen-containing gas, which were than activated and converted to synthesis gas. The effect of input power, various oxygen-containing gas and composition of the gas mixture were investigated. The conversion of methane reached up to 100%. In all cases, hydrogen and carbon oxide were produced as primary products, and other compounds was generated. The conversion of methane and the yield of hydrogen and carbon oxides were increased with increasing the input power. Depending on the oxygen-containing gases, the composition of synthesis gas was varied.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.1
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• pp.8-12
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• 2005

Indium tin oxide(ITO) surface treated by Oxygen plasma has been in situ analyzed using XPS(X-ray Photoelectron Spectroscopy) and EDS(Energy Dispersive Spectroscopy), to investigate the relations between the properties of the ITO surface and the properties of OLED(Organic Light Emitting Diode). We measured electrical resistivity using Four-Point-Probe and calculated sheet resistance, and ITO surface roughness was measured by AFM(Atomic Force Microscope). We fabricated OLED using substrate that was treated optimum ITO surface. The plasma treatment of the ITO surface lowered the operating voltage of the OLED. We have obtained an improvement of luminance and decrease of turn-on voltage.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.113-113
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• 1994

• Clean Technology
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• v.7 no.3
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• pp.203-214
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• 2001

A silicon oxide cleaning characteristic and its mechanism were studied in RF plasma cleaning system with various gases such as $CHF_3$, $CF_4$, Argon, oxygen and mixing gas. The experimental parameters - working pressure (100 mTorr), RF power (300 W, 500 W), electrode distance (5cm, 8cm, 11.5cm), cleaning time (90, 180 seconds), gas flow (50 sccm) were fixed to compare cleaning efficiency by gas types. The results were as follows. First, the argon plasma is retaining only physical sputtering effect and etch rate was low. Second, the oxygen plasma showed good cleaning efficiency in electrode distace of 5cm, 300W, 180secs, but surface roughness increased. Third, $CF_4$ Plasma could get the best cleaning efficiency. Fourth, $CHF_3$ plasma could know that addition gas that can lower the CFx/F ratio need. We could not get good cleaning efficiency in case of added argon to $CHF_3$. But, we could get good cleaning efficiency in case added oxygen.

• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.167-272
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• 1998

The fluorine doped silicon oxide (SiOF) intermetal dielectric (IMD) films havc been of interest due to their lower dielectric constant and compatibility with existing process tools. However, instability issues related to hond and increasing dielectric constant due to water absorption when the SiOF film was exposured to atmospheric ambient. Therefore, the purpose nf this research is to study the effect of post oxygen plasma treatment on the resistance of nioisture absorption and reliability of SiOF film. Improvement of moisture ahsorption resistance of SiOF film is due to the forming of thin $SiO_2$ layer at the SiOF film surface. It is thought that the main effect of the improvement of moisture absorption resistance was densification of the top layer and reduction in the numher of Si-F honds that tend to associate with OH honds. However, the dielectric constant was inucased when plasma treatment time is above 5 min. In this study, therefore, it is thought that the proper plasma treatment time is 3 min when plasma treatment condition is 700 W of microwave power, 3 mTorr of process pressure and $300^{\circ}C$ of substrate temperature.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.142-149
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• 2008

This paper proposes an effective decomposition method of trichloroethylene using pellet packed-bed non-thermal plasma reactor and catalyst. For that, two types of reactors filled with manganese dioxide and alumina pellets are designed. When $MnO_2$ packed reactor is used, TCE decomposition rate is high due to the generation of oxygen atom radicals at the surface of catalyst during ozone decomposition. In addition, When $Al_2O_3$ packed reactor is used, TCE is oxidized into DCAC and it did not decomposed into small molecules such as COx and $Cl_2$. However, the plasma processed gas using $Al_2O_3$ packed reactor is passed through the $MnO_2$ catalyst reactor, which is placed at the downstream of plasma reactor, the decomposition rate increased as well due to oxygen atom radicals through ozone decomposition. Therefore, the adequate use of $MnO_2$ catalyst in the plasma process is very promising way to increase the decomposition efficiency.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.534-540
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• 2023

The high-rate performance is limited by several factors, such as polarization generation, low electrical conductivity, low surface energy, and low electrolyte permeability of CF_X, which is widely used as a cathode active material in the lithium primary battery. Therefore, in this study, we aimed to improve the battery performance by using carbon fluoride modified by surface treatment using oxygen plasma as a cathode for lithium primary batteries. Through XPS and XRD analysis, changes in the surface chemical characteristics and crystal structure of CF_X modified by oxygen plasma treatment were analyzed, and accordingly, the electrochemical characteristics of lithium-ion primary batteries were analyzed and discussed. As a result, the highest number of semi-ionic C-F bonds were formed under the oxygen plasma treatment condition (7.5 minutes) with the lowest fluorine to carbon (F/C) ratio. In addition, the primary cell prepared under this condition using carbon fluoride as the active material of the cathode showed the highest 3 F/C(3 C rate-performance) rate-performance and maintained a relatively high capacity (550 mAh/g) even at high rates. In this study, it was possible to produce lithium primary batteries with high-rate performance by adjusting the fluorine contents of carbon fluoride and the type of carbon-fluorine bonding through oxygen plasma treatment.

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.96-101
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• 2008

The magnesium oxide (MgO) protective layer plays an important role in plasma display panels (PDPs). Our previous work demonstrated that the properties of MgO thin film could be improved, which were deposited by Ion-Beam-Assisted Deposition (IBAD). However arc discharge always occurs during the IBAD process. To avoid this problem, Oxygen-Neutral-Beam-Assisted Deposition (NBAD) is used to deposit MgO thin films in this paper. The energy of the oxygen neutral beam was used as the parameter to control the deposition. The experimental results showed that the oxygen neutral beam energy was effective in determining in structural and discharge characteristics. The lowest firing inception voltage, the highest brightness and the highest luminous efficiency were obtained when the MgO thin film was deposited with an oxygen neutral beam energy of 300eV. The surface morphology of MgO thin film was also analyzed using AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy).

• Journal of the Korean Vacuum Society
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• v.18 no.6
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• pp.488-493
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• 2009

We developed a simple method to control the length of carbon nanotube array by using oxygen plasma etching. In this way, we could obtain a carbon nanotube with a uniform length (20, 30, 50, $70\;{\mu}m$), that was parallel to the substrate. Moreover, our growing method of carbon nanotube array gives a uniform diameter ~3.5nm, which is consistent with our previous results. Using the same etching method, we demonstrated the carbon nanotube radio frequency identification (RFID) antenna. The results could be useful for carbon nanotube applications such as flexible and transparent conductive films.

• Journal of Yeungnam Medical Science
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• v.15 no.1
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• pp.97-113
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• 1998

The sympathoadrenal system plays an important role in homeostasis in widely varing external environments. Conflicting findings, however, have been reported on its response to hypoxia. We investigated the effect of hypoxia on the sympathoadrenal system in dogs under halothane anesthesia by measuring levels of circulating catecholamines in response to graded hypoxia. Ten healthy mongreal dogs were mechanically ventilated with different hypoxic gas mixtures. Graded hypoxia and reoxygenation were induced by progressively decreasing the oxygen fraction in the inhalation gas mixture from 21%(control) to 15%, 10% and 5% at every 5 minutes, and then reoxygenated with 60% oxygen. Mean arterial pressure, central venous pressure and mean pulmonary arterial pressure were measured directly using pressure transducers. Cardiac output was measured by the thermodilutional method. For analysis of blood gas, saturation and content, arterial and mixed venous blood were sampled via the femoral and pulmonary artery at the end of each hypoxic condition. The concentration of plasma catecholamines was determined by radioenzymatic assay. According to the exposure of graded hypoxia, not only did arterial and mixed venous oxygen tension decreased markedly at 10% and 5% oxygen, but also arterial and mixed venous oxygen saturation decreased significantly. An increased trend of the oxygen extraction ratio was seen during graded hypoxia. Cardiac output, mean arterial pressure and systemic vascular resistance were unchanged or increased slightly. Pulmonary arterial pressure(PAP) and pulmonary vascular resistance(PVR) were increased by 55%, 76% in 10% oxygen and by 82%, 95% in 5% oxygen, respectively(p<0.01). The concentrations of plasma norepinephrine, epinephrine and dopamine increased by 75%, 29%, 24% in 15% oxygen and by 382%, 350%, 49% in 5% oxygen. These data suggest that the sympathetic nervous system was activated to maintain homeostasis by modifying blood flow distribution to improve oxygen delivery to tissues by hypoxia, but hemodynamic changes might be blunted by high concentration of nitrous oxide except PAP and PVR. It would be suggested that hemodynamic changes might not be sensitive index during hypoxia induced by high concentration of nitrous oxide exposure.