• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.11a
• /
• pp.9-12
• /
• 2004

Recently, the environmental problem has received considerable attention. so, many lamps have been developing for environmental requirement and energy efficiency. also, at glow discharge lamp researchers try to reduce energy spending that is power saving lamp. this kind requirement agree with strong points of electrodeless fluorescent lamp has received to now lighting sauce. At low pressure as mTorr I.C.P make high density plasma easily, is good to maintain discharge, has high ionization and does not have failing lighting and losing ability of electron radiation by oxidation and volatilization of electrodes, because this tape does not have electrodes This point of I.C.P can use at electrodeless fluorescent lamp in this study ICP display elements and Ar, Ne, Kr are researched for optical characteristic. each gas is looked into optical characteristic, also mixed gases is experiment for optical characteristic.

• Journal of Korean Society for Atmospheric Environment
• /
• v.24 no.6
• /
• pp.641-648
• /
• 2008

A plate-type dielectric barrier discharge (DBD) reactor was designed and tested for removal of gaseous toluene. The DBD reactor consisted of 9 parallel plate electrodes, four of which were grounded. An AC voltage of rectangular waveform ($5{\sim}8.5kV$, $60{\sim}1,000Hz$), was applied to the other five electrodes. The gaseous toluene passed through the DBD reactor and its concentration was measured by a real-time gas analyzer. The carbon monoxide (CO) and carbon dioxide ($CO_2$) which were produced by decomposition of toluene in the DBD reactor, were sampled and analyzed by a micro gas chromatography. The maximum toluene removal efficiency was 51.4%.

• KIEE International Transactions on Power Engineering
• /
• v.3A no.4
• /
• pp.214-221
• /
• 2003

In view of the fact that gas insulated switchgear (GIS) is an important piece of equipment in a substation, it is highly desirable to continuously monitor the state of equipment by measuring the partial discharge (PD) activity in a GIS, as PD is a symptom of an insulation weakness/breakdown. However, since the PD signal is relatively weak and the external noise makes detection of the PD signal difficult, it therefore requires careful attention in its detection. In this paper, the algorithm for detection of PD in the GIS using the wavelet transform (WT) is proposed. The WT provides a direct quantitative measure of the spectral content and dynamic spectrum in the time-frequency domain. The most appropriate mother wavelet for this application is the Daubechies 4 (db4) wavelet. 'db4', the most commonly applied mother wavelet in the power quality analysis, is very well suited to detecting high frequency signals of very short duration, such as those associated with the PD phenomenon. The proposed algorithm is based on utilizing the absolute sum value of coefficients, which are a combination of D1 (Detail 1) and D2 (Detail 2) in multiresolution signal decomposition (MSD) based on WT after noise elimination and normalization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.1151-1154
• /
• 2003

Ultraviolet rays, OH H O radical and $O_3$ produced by the streamer discharge in water are widely used to deactivate microorganisms and remove organic contaminants in water and the dominant factor of these decomposition is the oxidized reaction of hydrogen peroxide and dissolved $O_3$ in water. In this paper, the barrier discharge was used to create plasma in a gas, liquid and solid medium and the electrode with the reactor combined barrier with packed type(BPR) was made as noncontact way against water so that the effect of water characteristic change by the erosion of electrodes exposing in water should be minimized. The active radical and $O_3$ gas generated in plasma region were reacted into the water as electrode so that at the same time a dissolved $O_3$ and hydrogen peroxide were formed in water and The change of pH and conductivity were measured.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.1176-1179
• /
• 2003

Low-Pressure inductively coupled RF discharge sources have important industrial applications mainly because they can provide a high-density electrodeless plasma source with low ion energy and low power loss. In an inductive discharge, the RF power is coupled to the plasma by an electromagnetic interaction with the current flowing in a coil. In this paper, the experiments have been focussed on the electric characteristic and carried out using a single Langmuir probe. The internal electric characteristics of inductively coupled Ar RF discharge at 13.56 [MHz] have been measured over a wide range of power at gas pressure ranging from $1{\sim}70$ [mTorr].

• 전기의세계
• /
• v.26 no.6
• /
• pp.78-85
• /
• 1977

This paper studies flashover voltage and surface corona loss of A.C and D.C in the mixed gas of air and SF$_{6}$ for solid insulators P.V.C, arcylic, glass and bakelite in two cases. In one case, those solids are covered with transformer oil and the other case, those solids are not covered with it. 1) The flashover voltage for each solids in SF$_{6}$ is more than three times compared with that in the air. The flashover voltage for P.V.C is the highest and then arcylic, glass, bakelite in a decreasing order. 2) The more the amount of SF$_{6}$ in the mixing ratio, the less corona loss. The P.V.C shows the least amount of corona loss and the bakelite the largest. 3) Compared with the corona loss of positive polarity and the negative polarity, the former has less corona loss than the latter. 4) The more the number of flashover discharge, the less insulation of each solids, but in case of bakelite, insulation almost vanishes after a couple of discharge. 5) When each insulator is covered with transformer oil, the flashover voltage generally increases and the corona loss decreases.eases.

• Journal of Power System Engineering
• /
• v.13 no.3
• /
• pp.27-32
• /
• 2009

Numerical analysis information of a complex discharge-passage will be very useful to improve hydrogen compression system. General information about an internal gas flow is presented by numerical analysis approach. Relating with hydrogen compressing system, which have an important role in hydrogen energy utilization, this should be a useful tool to observe the flow quickly and clearly. Flow characteristic analysis, including pressure and turbulence kinetic energy distribution of hydrogen gas from cylinder going to the chamber of a reciprocating compressor are presented in this paper. Discharge-passage model is designed based on real model of hydrogen compressor. Pressure boundary conditions are applied considering the real condition of operating system. The result shows pressure and turbulence kinetic energy are not distributed uniformly along the passage of the hydrogen compressing system. Path line or particles tracks help to demonstrate flow characteristics inside the passage. The existence of vortices and flow direction can be precisely predicted. Based on this result, the design improvement should be done. Consequently, development of the better hydrogen compressing system will be achieved.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.167-167
• /
• 2012

최근 들어 유연한 폴리머 기판을 이용한 차세대 Flexible display는 다양한 장점으로 인해 많은 연구가들에 의해 유망한 차세대 디스플레이로 주목받고 있다. 일반적 폴리머 기판은 산소, 수분 등에 취약하기 때문에 무기막 또는 멀티레이어를 증착한다. 본 연구는 remote-type과 direct-type DBD로 구성되어 있는 double discharge system을 이용한 SiOx 무기막 증착 실험에 관한 연구이다. 본 연구에서는 HMDS/$O_2$/He/Ar gas mixture를 통해 발생된 대기압 플라즈마를 이용하여 공정을 진행하였다. SiOx를 증착할 때 SiOx 무기막 증착 실험은 $O_2$의 유량이 감소할수록 그리고 HMDS의 유량이 증가함에 따라 deposition rate, 즉 공정효율이 증가하는 것을 알 수 있었다. 하지만 HMDS의 유량이 증가하고 $O_2$ gas 유량이 감소함에 따라 carbon과 hydrogen 등의 불순물의 함유도 함께 증가하게 되고 이로 인해 무기막의 특성이 약해지고, 유기적인 막 특성이 강해지게 된다. Double discharge system을 사용하였을 경우에는 remote-type DBD system을 사용하였을 때 보다 더 높은 공정 효율을 관찰할 수 있었고 동시에 더 낮은 불순물 함량을 가지는 것을 알 수 있었다. 이는 기판에 추가적으로 인가되는 power에 따라 discharge efficiency가 향상되어 Si-O bond 결합을 유도, 무기막적 특성이 강해지고, 또한 기판 바이어스 효과에 따라 증착무기막의 기계적인 강도 역시 향상됨을 관찰할 수 있었다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.2
• /
• pp.70-77
• /
• 2012

The selective catalytic reduction(SCR) system used to reduce NOx in diesel engines requires an NO/$NO_2$ ratio of about 1 in exhaust emissions to realize the fast SCR mode at temperatures lower than $300^{\circ}C$. This study investigated the characteristics of a plasma system as a pre-active apparatus for the fast SCR reaction mode of an SCR system. Plasma was generated by the pulse corona discharge(PCD) method with a four-channel wire-cylinder reactor. This study showed that plasma was easily generated in the exhaust gas by the PCD system, and the peak voltage of the normal state condition for plasma generation was generally 12 kV. The PCD system easily converted NO into $NO_2$ at lower temperatures and the NO/$NO_2$ conversion ratio increased with the discharge current for plasma generation. But the PCD system could not convert NO into $NO_2$ at higher engine speeds and higher engine loads due to the lack of oxygen in exhaust gas. The PCD system also activated the diesel oxidation catalysts(DOC) system to reduce CO emissions.

• Analytical Science and Technology
• /
• v.5 no.2
• /
• pp.185-190
• /
• 1992

A gas-jet assisted glow discharge lamp was attached to a conventional atomic absorption spectrophotometer in the place of a flame burner. To evaluate the accuracy of this method, the certified values and the analyzed values of SRM's were compared and atomic absorption sensitivity for five elements were also obtained. Factors affecting the sensitivity and areas for future improvement are discussed.