• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.604-607
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• 2005

In the electro-discharge machining the machining performance is closely related to the characteristics of discharge which can be identified from electrical behavior in gap between workpiece and electrode. Therefore, the accurate prediction of electrical behavior in electro-discharge machining (EDM) is useful to process control and optimization. However, any simulation model fur prediction of electrical behavior in EDM process has never been reported until now. In this study, a simulation model is developed to analyze the electrical behavior of electro-discharge plasma which significantly influences electrical behavior in EDM process. For the purpose of this the fundamentals of electro-discharge mechanism such as inception, propagation, formation of plasma channel and termination are investigated to accurately predict the cycle of discharge plasma in EDM. As a result, a mathematical model of electro-discharge plasma is constructed with considering the fundamentals of electro-discharge plasma. Consequently, it is demonstrated that the developed model can predict the electrical behavior of plasma such as electron density in various conditions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.145-145
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• 2011

Recently, multi-hole electrode RF capacitively coupled plasma discharge is being used in the deposition of microcrystalline silicon for thin film solar cell to increase the speed of deposition. To make efficient multi-hole electrode RF capacitively coupled plasma discharge, the hole diameter is to be designed concerning the plasma parameters. In past studies, the relationship between plasma parameters such as pressures and gas species, and hole diameter for efficient plasma density enhancement is experimentally shown. In the presentation, the relationship between plasma deriving frequency and hole diameter for efficient multi-hole electrode RF capacitively coupled plasma discharge is shown. In usual capacitively coupled plasma discharge, plasma parameter, such as plasma density, plasma impedence and plasma temperature, change as frequency increases. Because of the change, the optimum hole diameter of the multi-hole electrode RF capacitively coupled plasma for high density plasma is thought to be modified when the plasma deriving frequency changes. To see the frequency effect on the multi-hole RF capacitively coupled plasma is discharged and one of its electrode is changed from a plane electrode to a variety of multi-hole electrodes with different hole diameters. The discharge is derived by RF power source with various frequency and the plasma parameter is measured with RF compensated single Langmuir probe. The shrinkage of the hole diameter for efficient discharge is observed as the plasma deriving frequency increases.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.324-325
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• 2008

In this Study, We fabricated a plasma discharge cluster with external electrodes which can be applied to flexible backlight in a polymer substrate and investigated the discharge characteristics. The Sealing process was progressed in vacuum chamber, which enable to fabricate plasma discharge cluster. The results of discharge characteristics show that the static memory margin of plasma discharge cluster was increased, as Ne/Xe(5%) gas pressure was increased. also, When gas pressure was 100torr at 600um of electrode gap, we have obtained high luminance of a plasma discharge cluster.

• 전기학회논문지
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• 제56권1호
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• pp.151-155
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• 2007

A compact discharge plasma system with a photocatalyst has been proposed and investigated experimentally for application to air conditioners. It was found that there was intense ultra violet radiation with high energy of 3.2 eV from the corona discharge due to the DC-biased pulse voltage applied on a wire. An electrophotochemical reaction took place apparently on the surfaces of the photocatalyst of $TiO_2$ irradiated ultra violet front the discharge plasma in the proposed plasma system. The proposed discharge plasma system with the photocatalyst of $TiO_2$ showed very high removal efficiency of VOCs by tile additional electrophotochemical reactions on the photocatalyst. The proposed discharge plasma system also showed very high removal efficiency of particles such as smokes, suspended bacteria, and pollen and mite allergens by the electrostatic precipitation part. This type of corona discharge plasma system with a photocatalyst can be used as an effective means of removing both indoor pollutant gases and particles including suspended allergens.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.162.1-162.1
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• 2015

The use of plasma has increased in bio-application field in recent years. Particularly, water treated by arc discharge or atmospheric pressure plasma has been actively utilized in bio-industry. In this study, we have developed a plasma activated water generating system. For this system, two kinds of plasma sources; dielectric barrier discharge (DBD) plasma and arc discharge plasma have been used. The discharge energy was calculated using the breakdown voltage and current, and the emission spectrum was measured to investigate the generated reactive species. We also analyzed the amount of reactive oxygen and nitrogen species in water using the chemical methods and nitric oxide sensor. Finally, the influence of plasma generated reactive species on the germination and growth of spinach (Spinacia oleracea) was investigated. Spinach is a green leafy vegetable that contains a large amount of various physiologically active organic compounds. However, it is characterized with a low seed germination rate.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.209.2-209.2
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• 2016

Up to now, Plasma applications are thought as a leading technology in industrial, chemical and even medical and biological field. Especially, Due to direct discharge in liquid with reaction in ambient solution, plasma in liquid is useful plasma technology. Such as electro-surgery, water purification, radical generation for synthesis. For using those plasma applications efficiently, plasma characteristics should be understood in advance. But discharge in liquid is not much well-known about its characteristics. And plasma discharge in solution is difficult to generate and analysis due to electrolysis, vaporization and radical generation. So, We make stable plasma discharge in solution(saline 0.9%) without input gas. We also analyze new type of plasma source in thermal and electrochemical view. And we check characteristics of plasma in liquid. For example, plasma density and radical density(OH) with optical emission, thermal energy with thermometer, electrical energy with oscilloscope and so on. And we try to explain the bubble and plasma formation with circuit analysis.

• 한국항공우주학회지
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• 제40권6호
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• pp.492-498
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• 2012

DBD(Dielectric Barrier Discharge) 플라즈마 액츄에이터의 설계 파라미터에 따른 특성을 연구하였다. 방전전압, 주파수, 전극의 간격, 폭, 길이, 유전체 두께에 따른 DBD 플라즈마 액츄에이터의 유속 및 소모전력을 측정하였다. 방전전압과 주파수가 클수록 유속과 소모전력은 증가하였다. 전극간격은 클수록 소모전력은 감소하면서 유속은 증가하였으나, 플라즈마 방전을 위해 높은 전압이 요구되었다. 상부전극폭은 좁을수록, 하부전극폭은 넓을수록 일정한 소모전력으로 유속을 증가시킬 수 있었다. 주어진 방전조건과 전극형상에서 DBD 플라즈마 액츄에이터의 성능을 예측할 수 있을 것으로 기대된다.

• 한국대기환경학회지
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• 제14권4호
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• pp.333-342
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• 1998

Plasma process has great possibilities to remove SOx, NOx simultaneously with high treatment efficiency and is expected to be suitable for small or middle plants. It was accomplished to evaluate SO2, NOx control possibility and achieve basic data to control pollutants by use of Surface Discharge Induced Plasma Chemical Process (SPCP) in this study. O3 generation characteristics by discharge of a plate was proportional to O2 concentration and power consumption and inversely proportional to temperature and humidity, In case of dry air, NOx was highly generated by N2 and O2 in air during the plasma discharge process but it was decreased considerably as H2O was added. SO2 removal efficiency was very high, and removal rate was 170,350 mEA at 30,50 watt respectively in flue gas which is usually contain HIO. NOx removal efficiency was about 57% at 40 watt power consumption with 7.5% humidity. It is estimated that H2O has an important role in reaction mechanism with pollutants according to plasma discharge.

• 한국안전학회지
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• 제15권3호
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• pp.66-70
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• 2000

In order to cope with environmental problems caused by harmful gases emitted from various industrial sources, a new technology which employs discharge plasma formed in ordinary atmospheric pressure has been intensively investigated in many industrialized nations. Although a plenty of useful outcomes and suggestions have been made public by scientists in this field, few commercial products which effectively decompose pollutant gases have appeared as yet. This is partly because that the energy efficiency of a most effective plasma reactor has not reached a satisfactory level in comparison with those of devices using conventional technologies. In an attempt to solve the problem mentioned above, we noticed to combine heterogeneous electrical discharges. This concepts is based on that each plasma reactor has its specific spatial region in which chemical reaction are active and by electrically affected with another reactor of different type, the activated region would increase - which may lead to cutting down the energy consumption. To prove this concept experimentally, two different discharge equipments, a plane ceramic-based surface discharge electrode and a corona electrode with tungsten needle may, are selected and combined to fabricate a hybrid plasma reactor. The results are summarized as follows; (1) Ozone concentration generated in the plasma region drastically increases when the positive corona discharge is added to the surface discharge. The rate of increase of ozone depends on the frequency of the surface discharge. The negative corona, however, does not contribute to the improvement of the ozone generation. (2) NO(nitrogen monoxide) decomposition rate also improves by simultaneously applying the surface and the positive corona discharges. The effect of the corona superposition is more evident when the level of the surface discharge is moderate. (3) By adjusting the corona level, the net energy efficiency during NO decomposition improves in comparison with the simple surface discharge reactor.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.585-588
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• 2007

We studied the effect of self-erase discharge on the luminous efficacy of ac PDPs. We observed through discharge current analysis to confirm that the selferase discharge occurred mainly between sustain cathode and address electrode, which have an influence on the luminous efficacy. The amount and timing of the self-erase discharge was varied to observe its effect on the luminous efficacy. It has been found that the luminous efficacy could be improved by the self-erase discharge when it is adjusted to occur right before the main discharge in the small gap structure. In the long gap structure, on the contrary, the luminous efficacy could be increased when the self-erase discharge is suppressed. Also, various waveforms to control self-erase discharge are suggested and tested in the panel experiments.