Sang-Bo Han

Evaluation of Discharge Characteristics Followed by the Development of Blumlein Pulsed Power Source

This paper discussed the theoretical simulation results for developing the blumlein pulsed power source and showed the circuit configuration and the discharge characteristics of the realistic manufactured pulsed power system. In the simulation, the output voltage characteristics at a load resistor showed the general impulse shape when the impedance of a single coaxial cable is matched with the that of a load resistor. In addition, it is confirmed that output values of the pulsed power can be easily controlled by the duplication of coaxial cables and the pulsed waveform showed the general impulse characteristics. Specifically, the inception discharge voltage in the gap distance of 5[mm] between needle and plane electrodes is about 20[kV] and which is lower than about 29[kV] in 9[mm] due to the difference of the reaching time of the inception voltage. Therefore, this paper showed that the output voltage of the blumlein pulsed power source can be easily controlled.

A Study on the Effect of Magnetic Field in Electrostatic Precipitator for Improving Precipitation Efficiency of Particulate Matter

본 논문은 실내에 잔존하는 직징 1[μm] 이하의 미세먼지들을 집진하기 위하여 전기집진기를 설계하였으며, 이때 집진 효율의 극대화를 위하여 전계와 동시에 자계를 수직 및 수평으로 배치함에 따른 실험실 공기중에 포함된 미세먼지의 집진특성에 대하여 논하였다. 전계에 수평으로 자계를 인가한 경우는 자계의 유무 및 자석의 수량에 관계없이 집진효율이 거의 일정하게 나타났으며, 자석을 수평으로 배치하여 전계에 수직으로 인가한 경우는 비자화 페라이트 막대를 부착한 경우보다 약 5[%] 이상 집진효율이 향상되었다. 또한, 자계를 전계에 수직으로 인가하는 방법에 있어서, 자석을 접지전극의 가운데 정렬한 경우는 인가진압 5[kV]에서의 집진효율이 17~32[%]로서 자석을 앞쪽에 설치한 경우와 유사하였으며, 지그재그 및 안쪽 끝에 정혈시킨 정우는 집진효율이 17~38[%]로서 향상되었으며, 특히 0.7 및 1[μm]의 굵은 입자들에 대한 집진특성이 양호하였다. 따라서, 전기집진기의 집진특성을 향상시키기 위해서는 자계를 진계에 수직으로 접지전극의 중간 또는 지그재그 식으로 배치하는 것이 가장 적절한 것으로 판단된다.

The Effect of Conductivity on Active Species Products by Electrical Discharge with Air Bubbles in Water

Abstract The oxidative reactions of OH, H, and O radicals, H2O2, and O3 produced by plasma energy are widely applied to purify an aqueous solution and to decompose phenolic compounds and microorganisms. In this paper, the wet packed-barrier reactor (WPBR) filled with glass and the ZrO2 pellets was used and the high voltage of frequency 20 ~ 30 kHz was applied to create the electrical discharge plasma. Electrodes of the reactor did not contact with water directly, because water contamination by the erosion of electrodes exposed to the water should be minimized. The effect of water conductivity on the dissolved ozone and hydrogen peroxide concentrations in water were investigated by comparing the results with tap water and those of distilled water. Active radicals and ozone generated in the plasma region may react with water to lead to the dissolved ozone and hydrogen peroxide formation simultaneously in water. Concentrations of the dissolved ozone and hydrogen peroxide in the case of tap water with the conductivity of 80 μS/cm was much higher than those in the case of the distilled water with the conductivity of about 0 S/cm. The maximum concentration of the dissolved O3 and H2O2 were 1.58 ppm and 2.4 ppm, respectively. After plasma treatment, the conductivity of the distilled water increased, but those of tap water decreased.

Operating Characteristics of LED Package Heat-sink with Multi-Pin`s

This paper is proposed to design the new heat-sink apparatus for improving the heat transfer characteristics in the power LED chip, and results of the operation characteristics were discussed. The core design is that the soldering through-hole on the FR-4 PCB board is formed to the effective heat transfer. That is directly filled with Ag-nano materials, which shows the high thermal conductivity. The heat transfer medium consisting of Ag-nano materials is classified into two structures. Mediums are called as the heat slug and the multi-pin in this work. The heat of the high temperature generated from the LED chip was directly transferred to the heat slug of the one large size. And the accumulated heat from the heat slug was quickly dissipated by the medium of the multi-pin, which is the same body with the heat slug. This multi-pin was designed for the multi-dissipation of heat by increasing the surface areas with a little pins. Subsequently, the speed of the heat transfer with this new heat-sink apparatus is three times faster than the conventional heat-sink. Therefore, the efficiency of the illuminating light will be improved by adapting this new heat-sink apparatus in the large area`s LED.

Study on the Temporal Density Variation of Chemical Species in the Atmospheric Pressure Plasma Process

This study is to discuss simulation results with 51 principal chemical reactions in non-thermal plasma space under atmospheric pressure, and the ambient gas was mainly composed of oxygen and nitrogen molecules. The initial density of O and OH radicals under the ambient temperature of 300K is largely generated in comparison with other higher temperature, and the density of O radical decreased from according to increase the temperature. The initial density of OH radical seemed to decrease steeply at the initial stage. By increasing the initial density of molecules, O radicals effect was few and the density of OH radical was largely generated about 2 times. In addition, ozone density was increased as increasing the density of O radical, but it was decreased as increasing the density of . In case of the temperature more than 300K, tend to be removed, but NO was increased than the initial density.

A Study on the Measurement of Vibrational and Rotational Temperature Using the Atmospheric Ar Plasma Torch

This work was carried out for the measurement of vibration and rotation temperature using the optical emission spectroscopy of nitrogen second positive system in the small plasma torch. Among emissions N2 SP systems, the emission of N2 SP(0-0) was so strong. Emission peaks of SP system increased until the position of 12.5(mm) from the end of plasma torch, after that it decreased. However, vibration temperature decreased from 1540(K) to 1000(K) at the position of 12.5(mm). In addition, rotational temperature was about 400(K) at the position of 10(mm) and it increased a little as much of 420(K) at 12.5(mm). Consequently, the plasma torch discussed in this work is possible to apply in the surface treatment process under the low temperature.

A Study on an Operating Conditions for the Direct Ethanol Fuel Cell

Abstract - The goal of this paper is to find an operating conditions of the single direct ethanol fuel cell such as the cell temperature, and flow rates of ethanol and oxygen. To investigate the output characteristics, the electrical current increased from 0[A] with interval of 0.001[A] every 2[s], and the cell voltage was increased until the voltage became 0.05[V]. Related to the effect of the cell temperature, the output characteristics both voltage and power were increased upto 80[℃] according to the increase of the current density, but those were decreased over that temperature. In addition, the optimal flow rate of ethanol in anode was identified as of 2[mL/min] due to the dependence of generation rate such as the hydrogen ion and electron. And the flow rate of oxygen in cathode was desirable to about 300[sccm/min], it might be affected by the chemical reaction rate of the water formation among hydrogen ion, electron, and oxygen. Consequently, the fundamental conditions were identified in this work, and it will be carried out to find the best conditions of membrane by the effect of the plasma surface treatment, and the effect of other catalysts except for a platinum. Key Words : Direct ethanol fuel cell, Hydrogen ion, Operating conditions, Temperature, Voltage *정 회 원 : 경남대 전기공학과 박사과정** 비 회 원 : 경남대 전기공학과 공학석사***정 회 원 : 경남대 전기공학과 교수 † 교신저자, 정회원 : 경남대 전기공학과 교수 E-mail : jypark@kyungnam.ac.kr 접수일자 : 2011년 8월 24일 최종완료 : 2011년 10월 10일

A Study on the Optical Emission Spectroscopy of the RF Inductive Plasma Process

This paper is tried to analysis the optical emission spectroscopy related to the position of inductive load coil and flow rates of methane and oxygen in the RF inductive plasma process. According to the position of load coil, peak of , , and CH were appeared strongly at the middle position of the coil and it decreased both direction. The electron temperature was approximately 0.9[eV] at that position. Emission intensities of , , and CH increased linearly by increasing input power. In addition, intensities of and increased by increasing the flow rate of oxygen. It might be ascribed that the oxygen species were bonded with by suppressing the combination with hydrogen atoms. Consequently, the optimal position of the inductive coil is decided to the intermediate position between 4th and 5th turns, the wanted carbon thin-film is possible to deposit by controlling flow rates of methane and oxygen.

Characteristics of Hydrogen Production from Methanol and Ethanol Using Plasma Reactor and Ozone Decomposition Catalyst

In this work, the effect of the initial concentration of methanol and ethanol, and the addition of oxygen molecules were discussed to improve the hydrogen generation using non-thermal plasma reactor effectively. In addition, the effect of ozone decomposition catalyst of manganese dioxide and its quantity was investigated. First, hydrogen concentration increased until an initial concentration of about 40,000[ppm] of methanol and thereafter it was saturated. Henceforth, hydrogen concentration decreased with increasing the oxygen percent on the carrier gas of nitrogen about both substances. Related with the effect of catalyst, it increased upto 60[g], but it was not changed largely after that. Consequently, it is confirmed that the hybrid process using plasma process and catalytic surface chemical reaction is a very promising way to increase the efficiency of hydrogen generation as investigated in this work.

Fabrication and Properties of Diamond Thin-Film from N-Hexane by Using Microwave Plasma Process

In this paper, the best conditions for the deposition of the high quality diamond thin-film from N-hexane as a carbon source in the microwave plasma process was carried out. Major parameters are the deposition time, flow rates of oxygen and hexane. The deposition time for the steady state thin-film was required more than 4[h], and the suitable flow rates of hexane and oxygen for the high-quality thin-film are 0.4[sccm] and 0.1~0.2[sccm], respectively. In addition, amorphous carbons such as DLC and graphite were grown by increasing the flow rate of hexane, and it decreased by increasing the flow rate of oxygen. Specifically, the growth rate is about 1.5[] under no addition of oxygen and it decreased about 60[%] as ca. 1.0[] with oxygen.