• 전기학회논문지
• /
• 제67권9호
• /
• pp.1189-1196
• /
• 2018

7 type composites (40, 45, 50, 55, 60, 65, and 70 wt.%)were prepared for the environmentally friendly GIS Spacer. Five kinds of samples were prepared for optimization of the filler content ratio (MS: MA = 1: 9, 3: 7, 5: 5, 7: 3, 9: 1) of epoxy / microsilica and microalumina. As a result of evaluation of the partial discharge resistance characteristic, surface erosion is generally slowed down as the fill amount of micro silica is increased. Also, partial discharge resistance characteristics for the development of insulating materials with optimal mixing ratios of heterologous showed a higher partial resistance of discharge and a decrease in erosion, as the filler content ratio of micro silica was larger. In the future, various researches such as electrical, mechanical, and thermal studies will be needed to develop insulating materials that can commercialize power devices in environmentally friendly insulating gas.

• Applied Science and Convergence Technology
• /
• 제26권4호
• /
• pp.74-78
• /
• 2017

The discharge characteristics of the radio frequency (RF) surface dielectric barrier discharge have been simulated for the investigation of the ratio of the ion transit time to the RF period. From one-dimensional particle-in-cell (PIC) simulation for a planar dielectric barrier discharge (DBD), it was observed that the high-frequency driving voltage confines the ions in the plasma because of a shorter RF period than the ion transit time. For two-dimensional surface dielectric barrier discharges, a fluid simulation is performed to investigate the characteristics of RF discharges from 1 MHz to 40 MHz. The ratio of the peak density to the average density decreases with the increasing frequency, and the spatiotemporal discharge patterns change abruptly with the change in the ratio of ion transit time to the RF period.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권3호
• /
• pp.143-148
• /
• 2004

This paper shows property conversion of water and removing characteristics of Escherichia coli for discharge tube with $ZrO_2$ beads. At the result of the removal characteristic experiments of Escherichia coli using the discharge tube with $ZrO_2$ beads, because the electric field is also increased when input voltage is increased, the removal characteristic of Escherichia coli was appeared relation connection to input voltage. And if a passing number of test water in discharge tube with $ZrO_2$beads is increased, the removal ratio of Escherichia coli is to be increased because passing number of electric field section is increased. And if diameter of $ZrO_2$beads is increased, the removal time of Escherichia coli is to be decreased because dielectric polalization of $ZrO_2$beads. Also, the removal ratio of Escherichia coli of the discharge tube with $ZrO_2$beads. is appeared higher than the removal ratio of the discharge tube without $ZrO_2$beads. And a satulation punt of ozone and $H_2$ $O_2$generation density inner water was appeared near 60[min].

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
• /
• pp.546-549
• /
• 2003

This paper was shown removal characteristic of escherichia coli for discharge tube with globular $SiO_2$. At the result of the removal characteristic experiments of escherichia coli using the discharge tube with globular $SiO_2$, because the electric field is also increased when input voltage is increased, the removal characteristic of escherichia coli was appeared relation connection to input voltage. If a passing number of test water in discharge tube is increased, the removal ratio of escherichia coli is increased because passing number of electric field section is increased. When diameter of globular $SiO_2$ is increased, the removal time of escherichia coli is to be decreased because dielectric polalization of globular dielectric($SiO_2$), Also, the removal ratio of escherichia coli of the discharge tube with globular dielectric($SiO_2$) is appeared higher than the removal ratio of the discharge tube without globular dielectric($SiO_2$).

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
• /
• pp.550-553
• /
• 2003

This paper was shown water properly conversion and removal characteristic of escherichia coli for discharge tube with $ZrO_2$ beads. At the result of the removal characteristic experiments of escherichia coli using the discharge tube with $ZrO_2$ beads, because the electric field is also increased when input voltage is increased, the removal characteristic of escherichia coli was appeared relation connection to input voltage. And if a passing number of test water in discharge tube with $ZrO_2$ beads is increased, the removal ratio of escherichia coli is to be increased because passing number of electric field section is increased. And if diameter of $ZrO_2$ beads is increased, the removal time of escherichia coli is to be decreased because dielectric polalization of $ZrO_2$ beads. Also, the removal ratio of escherichia coli of the discharge tube with $ZrO_2$ beads. is appeared higher than the removal ratio of the discharge tube without $ZrO_2$ beads. And a salutation point of ozone and $H_2O_2$ generation density inner water was appeared near 60[min].

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 추계학술대회 논문집
• /
• pp.379-382
• /
• 2000

The characteristics of Xe discharge lamp(Mercuryless lamp) are described in this paper. In this paper, FFL is operated by sine wave and pulsed source. We apply V-Q Lissajous' figure for the discharge measurements of FFL which has the electrodes covered with dielectric. When FFL is operated by sine wave source, the characteristics are similar to DBD(Dielectric Barrier Discharge) and SD(Silent Discharge). And we compared the characteristics of FFL which is operated with sine wave and pulsed discharge by using V-Q Lissajous' figure method. When FFL is operated with pulsed, the discharge current flows after the applied voltage is risen. As the duty ratio increases the electric field becomes strong and much more xenon ions are produced. And the number of metastable xenon atoms seem to increase, therefore, the phosphor radiation after the cut off of voltage increases compared with the first peak of radiation. Consequently, the 172㎚ radiation becomes strong as the duty ratio increases.

• International Journal of Aeronautical and Space Sciences
• /
• 제3권1호
• /
• pp.1-8
• /
• 2002

A numerical analysis was performed on the fluid flow in injector orifice of a liquid rocket engine. The present computational code was verified against the published data for turbulent flow in a pipe with a sudden expansion-contraction. Considered were the parameters for the flow analysis in an injector orifice: Reynolds number, ratio of mass flow rate of the injector orifice and inlet flow rate, and slant angle of the injector orifice. The discharge coefficient increased slightly as the Reynolds number increased. The slant angle of the injector changed critically the discharge coefficient. The discharge coefficient increased by 7% when the slant angle changed from $-30^{\circ}$ to $30^{\circ}$ The ratio of mass flow rate had relatively little impact on the discharge coefficient.

• 한국수자원학회논문집
• /
• 제53권8호
• /
• pp.617-626
• /
• 2020

본 연구에서는 TELEMAC-2D를 이용하여 개수로 분류부에서 분류각과 분류유량비 변화에 따른 유속분포, 흐름분리구역의 크기, 분류각과 유량비 변화의 상관관계를 파악하였다. 상·하류단 경계조건의 변화 없이 분류각만 90°에서 45°로 감소하면 주흐름에서 분리되어 분류수로로 유입되는 흐름의 곡률반경이 증가하고 급격한 흐름방향의 전환에 의한 에너지손실은 감소하며, 주수로와 분류수로 하류방향으로 흐르는 흐름의 관성력과 하류단 경계조건에 의한 압력경사의 영향으로 분류수로에 유입되는 분류유량비가 0.523에서 0.785로 약 1.5배 증가하였다. 분류부 상류 유입흐름의 프루우드 수가 F₁ = 0.45~0.74인 흐름에서 분류각을 90°에서 45°로 15° 간격으로 감소할 때마다 분류유량비는 각각 6~10%, 17~30%, 32~54%로 비선형적으로 증가하며, F₁가 최대 0.74인 흐름에서 분류유량비 증가율이 31.1%로 최소값을 나타내고 F₁ = 0.58 일 때 분류유량비가 0.7 이하이면서 최대 분류유량비 증가율 53.5%을 나타내며, F₁이 0.58보다 감소할수록 분류유량비가 0.7을 초과하면서 그 증가율도 함께 감소하게 된다. F₁ > 0.4인 흐름은 F₁ < 0.4의 흐름보다 무차원 흐름분리구역의 폭(S_W/B) 변화율은 약 2.56배 높으며 무차원 흐름분리구역 길이(S_L/B) 변화율은 약 5.5배 높게 나타난다.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
• /
• pp.111-115
• /
• 2001

Durability of tunnel drains is important, because the accumulation of groundwater around the tunnel due to clogging of filter or reduction of discharge capacity of drain causes reduction of the life time of tunnel linings. In this paper, clogging and discharge capacity of drain and filter of tunnels are evaluated using a gradient ratio test and filter design criteria. The results of the gradient ratio test showed that gradient ratio(GR) is high when fine content is high in the soil samples and equivalent opening size(EOS) of filter materials is small. Measured GR was less than allowable critical gradinet ratio : 3.0, which is the clogging criteria of U.S. Army Corps of Engineers.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1412-1413
• /
• 1996

Li ion battery have many advantages such as high energy density, high voltage and low self discharge, so it will replace conventional Ni/Cd battery. But, charge-discharge characterization of Li battery is controlled by weight ratio of electrodes (Cathode/Anode). So, we performed a study on relation between charge/discharge characterization and weight ratio (cathode/anode).