• 한국연소학회:학술대회논문집
• /
• 2013.06a
• /
• pp.99-101
• /
• 2013

The equivalence ratio is measured by LIBS(Laser-induced Breakdown spectroscopy) in hydrocarbon flame and high temperature (${\sim}3200^{\circ}C$) oxyhydrogen flame, where a stoichiometric mixture of hydrogen and oxygen is produced from water through electrolysis. The ratio of the hydrogen and oxygen (H/O) atomic lines intensities is used for quantitatively determining the quivalence ratio. laser energy is evaluated for determining the optimal condition for plasma diagnostics. The minimum laser energy for generating plasma in a laminar premixed hydrocarbon flame was about 70 mJ, whereas oxyhydrogen flame. consequently the irradiated spot of a lower density in high temperature oxyhydrogen flame gave rise to bigger plasma in size, thus limiting the spatial resolution of the LIBS measurement.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.3
• /
• pp.577-582
• /
• 2007

The plasma display panel is an image expression display using gas discharge plasma. However, gas discharge characteristics vary with temperature as gas discharge is sensitive to temperature. The discharge time lag extends a lot in low temperature and it is known as the cause which hinders high speed addressing which is essential for the size enlargement of the panel. Accordingly this research aims at identifying the temperature-dependent discharge characteristic. The lower temperature becomes, the longer addressing discharge time lag becomes. Particularly the statistical time lag extends much in low temperature. The increasing of electric field shortens discharge time lag in low temperature. Also, when priming particles are sufficiently supplied, stable discharge can be performed regardless of the influence of temperature.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.889-892
• /
• 2009

A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 GHz and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and right now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Lastly, we briefly report an underway research, which is remediation of soils contaminated with oils, volatile organic compounds, heavy metals, etc.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.545-550
• /
• 2012

High Energy density metal powder has high melting point of oxide film. By this, the ignition source that can make a thermal effect of high-temperature during short time is needed to overcome ignition disturbance mechanism by oxide film. So effective ignition does not occurred with hydrocarbon ignitor, $H_2-O_2$ ignitor, high power laser. But steam plasma can be generate about 5000 K temperature field in short order. Because a steam plasma uses steam as the working gas, it is environmental-friendly and economical. Therefore in this study, we analyze steam plasma temperature field and radical species with optical emission spectroscopy method in order to apply steam plasma ignitor to metal combustion system and cloud particle ignition was identified in visual.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.748-751
• /
• 2003

The electron temperature and plasma density in coplanar alternating-current plasma display panels (AC-PDPs) have been experimentally investigated by a micro Langmuir probe and the high speed discharge images in this experiment.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.472-472
• /
• 2011

The capacitive coupled plasma (CCP) has been extensively used in the semiconductor industry because it has not only good uniformity, but also low electron temperature. But CCP source has some problems, such as difficulty in varying the ion bombardment energy separately, low plasma density, and high processing pressure, etc. In this reason, dual frequency CCP has been investigated with a separate substrate biasing to control the plasma parameters and to obtain high etch rate with high etch selectivity. Especially, in this study, we studied on the etching of $SiO_2$ by using the pulse-time modulation in the dual-frequency CCP source composed of 60 MHz/ 2 MHz rf power. By using the combination of high /low rf powers, the differences in the gas dissociation, plasma density, and etch characteristics were investigated. Also, as the size of the semiconductor device is decreased to nano-scale, the etching of contact hole which has nano-scale higher aspect ratio is required. For the nano-scale contact hole etching by using continuous plasma, several etch problems such as bowing, sidewall taper, twist, mask faceting, erosion, distortions etc. occurs. To resolve these problems, etching in low process pressure, more sidewall passivation by using fluorocarbon-based plasma with high carbon ratio, low temperature processing, charge effect breaking, power modulation are needed. Therefore, in this study, to resolve these problems, we used the pulse-time modulated dual-frequency CCP system. Pulse plasma is generated by periodical turning the RF power On and Off state. We measured the etch rate, etch selectivity and etch profile by using a step profilometer and SEM. Also the X-ray photoelectron spectroscopic analysis on the surfaces etched by different duty ratio conditions correlate with the results above.

• Fashion & Textile Research Journal
• /
• v.15 no.3
• /
• pp.461-466
• /
• 2013

Synthetic fiber materials were developed due the desire of consumers for high-quality, high-performance and comfort. A high functionality of synthetic fiber can be obtained through surface treatment that can improve hydrophilic properties, color depth after dyeing and adhesion properties. These advantages create added-value. Hydrophobic properties are an important feature to create added-value (such as hydrophilic properties). One side processing is a method of imparting to contrary function on the front and rear side. In this study, fluorine-coated Nylon/PU blended fabric was treated on only one side with a low-temperature plasma treatment; subsequently, the contact angles decreased by increasing the time and intensity of the plasma treatment. The contact angle of the untreated surface and the treated surface was different. It a showed a difference in the properties of both surfaces. Tensile strength and stiffness decreased by increasing the time and intensity of the plasma treatment. However, plasma treatment did not significantly change the tensile strength and stiffness on both surfaces of the fabric. SEM photographs showed the surface of fluorine-coated fabric and the etching surface by using plasma treatment on the fabric. Plasma treatment was confirmed not to affect the physical properties of the fabric.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.1859-1861
• /
• 2000

The high temperature thermal plasma technology applied to waste treatment has undoubtedly gained high importance owing to its outstanding properties such as flexibility, compact reactor. and clean treatment as the environmental problem goes to a main issue in public talks, because the thermal plasma with temperature of around 10,000K or little less is particularly suitable for waste treatment. Since the thermal plasma is, in general, governed by a number of parameters, some complicated and elaborate controls might be mandatory. The high maintenance cost caused by big input power has been a main obstacle to the growth of the waste treatment plant based on thermal plasma technology, but the recent R&D on the waste-to-energy shows that the problem could be solved soon. In this paper, the authors introduce the current R&D activity related to three-phase ac plasma torch in KERI.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.306-306
• /
• 2010

A high density (> $10^{11}\;cm^{-3}$) and low electron temperature (< 2 eV) plasma is produced by using a conventional HF (13.56 MHz) plasma enhanced chemical vapor deposition (PECVD) with an additional ultra high frequency (UHF, 314 MHz) plasma source utilizing two parallel antenna assembly. It is applied for the high rate synthesis of high quality nanocrystalline silicon (nc-Si) films. A high deposition rate of 1.8 nm/s is achieved with a high crystallinity (< 70%), a low spin density (< $3{\times}10^{16}\;cm^{-3}$) and a high light soaking stability (< 1.5). Optical emission spectroscopy measurements reveal emission intensity of $Si^*$ and $SiH^*$, intensity ratio of $H{\alpha}/Si^*$ and $H{\alpha}/SiH^*$ which are closely related to film deposition rate and film crystallinity, respectively. A high flux of precursor and atomic hydrogen which are produced by an additional high excitation frequency is effective for the fast deposition of highly crystallized nc-Si films without additional defects.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.11
• /
• pp.942-948
• /
• 2007

Popular techniques for producing hydrogen by converting methane include steam reforming and catalyst reforming. However, these are high temperature and high pressure processes limited by equipment, cost and difficulty of operation. Low temperature plasma is projected to be a technique that can be used to produce high concentration hydrogen from methane. It is suitable for miniaturization and fur application in other technologies. In this research, the effect of changing each of the following variables was studied using an AC GlidArc system that was conceived by the research team: the gas components ratio, the gas flow rate, the catalyst reactor temperature and voltage. Results were obtained for methane and hydrogen yields and intermediate products. The system used in this research consisted of 3 electrodes and an AC power source. In this study, air was added fur the partial oxidation reaction of methane. The result showed that as the gas flow rate, the catalyst reactor temperature and the electric power increased, the methane conversion rate and the hydrogen concentration also increased. With $O_2/C$ ratio of 0.45, input flow rate of 4.9 l/min and power supply of 1 kW as the reference condition, the methane conversion rate, the high hydrogen selectivity and the reformer energy density were 69.2%, 32.6% and 35.2% respectively.