• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 B
• /
• pp.1124-1126
• /
• 2004

The measurements were performed to assess the insulation deterioration condition of the stator winding of Dae-Cheong hydro-generator ${\sharp}2$ which had been in service after being constructed 1980. After repair of the stator winding insulation. we conducted insulation diagnostic tests which include resistance, polarization index(P. I). AC current, dissipation factor($Tan{\delta}$) and partial discharges ($Q_{max}$). The results of diagnostic tests were compared to the previous records. On the basis of these test results. this paper tried to present the importance of insulation repair for the generator stator winding.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2009년도 추계학술대회 초록집
• /
• pp.155-155
• /
• 2009

The copper plating was deposited by pulse reverse current (PRC) method with additives. The all specimens were first immersted in 10% H2SO4 for 10 minutes, and then were rinsed with deionized water. The current densities of forward pulse were 400mA/$cm^2$, and those of reverse pulse were 1900mA/$cm^2$ and 100mA/$cm^2$. Results are compared for different additives for pulse plating conditions. When it added in Only CH4N2S (TU) or only C10H13NO3S (SVH), the effect of surface side growth of Cu was not different. But when it added in TU and SVH, surface side growth of Cu decreased. Polarization curves were measured from OCP to -0.7 V at a rate of 1mV/sec. Each specimen was observed under the PHENOM to see surface morphology.

• 한국지리정보학회지
• /
• 제17권1호
• /
• pp.129-143
• /
• 2014

본 연구는 충주댐 유역($6,625.8km^2$)을 대상으로 지점강우와 소백산 이중편파 레이더강우자료를 격자기반 분포형 강우-유출 모형인 KIMSTORM(KIneMatic wave STOrm Runoff Model)에 적용하여 홍수추적을 수행하여 레이더의 적용성을 검토하였다. 2012년 4개의 강우 이벤트(집중호우, 카눈, 볼라벤, 산바)에 대하여 한강홍수통제소로부터 보정된 소백산 레이더 강우자료를 제공받아 사용하였다. 레이더 강우와 지점 강우를 비교분석한 결과, 41개 지점의 지상강우보다 레이더의 면적평균강우량을 비교한 결과, 강우의 시공간적 패턴은 상당히 일치하였고 지상강우에 대한 레이더 강우의 비율은 0.97로 분석되었다. 이후 분포형 홍수추적을 위해 KIMSTORM을 이용하였으며, 격자크기 $500{\times}500m$ 해상도의 198행${\times}$231열의 총 45,738개의 셀로 모형을 구축하였다. KIMSTORM 모형의 보정 결과, 평균 $R^2$(coefficient of determination), ME(model efficiency), VCI(volume conservation index)는 지상강우의 경우, 각각 0.83, 0.68, 1.10로 분석되었고, 레이더강우의 경우는 각각 0.80, 0.62, 1.08의 결과를 보였다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.319-322
• /
• 1999

Land surface hydrological conditions have been considered to play an important role in the global and regional climate variability. Especially, snow, soil moisture, surface temperature, vegetation and rain are the key parameters which should be observed in the global scale. In this paper, new algorithms for these land surface hydrological parameters have been developed by introducing frequency and polarization dependencies of these parameters in the microwave radiative-transfer equations. The algorithms were applied to the TRMM Microwave Radiometer. (TMI) and validated by using the ground data obtained in the Tibetan Plateau. The estimated snow, soil moisture, surface temperature, water content of vegetation and rain patterns corresponded reasonably to the observed ones.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 추계학술대회
• /
• pp.490-493
• /
• 2006

The results of simulation of direct methane fuel cell fed with liquid-state methanol feed are shown. This numerical process is based on mass and current conservation equations. The results showed that over low current density $(<200mA/cm^2)$ IV polarization curve was well-presented compared to experimental result. Methanol fed from anodic side moved into cathodic side through electrolyte membrane and the pressure near cathode electrode increased according to amount of methanol crossover and production of water. Besides change of overpotential on each el electrode were checked by x-axis.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 제2회 학술대회 논문집 일렉트렛트 및 응용기술전문연구회
• /
• pp.25-28
• /
• 2000

In this paper, the technology for accelerating degradation & life estimation on the traction motor was introduced with the stator form-winding sample coils of the 200 Class insulation system The accelerative degradation was performed in 10 cycles, which were composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, condition diagnosis test such as insulation resistance & polarization index, capacitance & dielectric loss and partial discharge properties were investigated in the temperature range of $20{\sim}160^{\circ}C$. Relationship between degradation conditions and diagnosis results were analyzed to find an dominative degradation factor at the end-life point

• 멤브레인
• /
• 제2권2호
• /
• pp.104-111
• /
• 1992

A curved channel duct is designed, built and used specifically to produce Dean vortices as a result of flow around a $180^{\circ}C$ curve. We present evidence using optical reflection of the existmace of the vortices in the curved section and following flat section. Also, three different feed soludons(DI water, a monodispersed styrene-divinyl-benzene latex particle suspension and a yeast suspension) were used to determine the effectiveness of Dean instabilities to destabilize polarization layers. For each suspension, the flux data were compared as a function of time for flow conditions with and without Dean vortices, for a $0.2{\mu}m$ microfiltration membrane. Any permeation flux improvement was not sustained for $2.0De_c$ due to the vortex-decay in the flat section after the curved channel, but a 15~30% permeation improvement was obtained for $3.8De_c$.

• 한국전기전자재료학회논문지
• /
• 제15권1호
• /
• pp.93-101
• /
• 2002

In this study, the stator form-winding sample coils based on silicone resin and polyimide were made for fault prediction and reliability estimation on the C-Class(200$\^{C}$ ) insulation system of traction motors. The complex accelerative degradation was periodically performed during 10 cycles, which was composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, the condition diagnosis test such as insulation resistance '||'&'||' polarization index, capacitance '||'&'||' dielectric loss and partial discharge properties were investigated in the temperature range of 20 ∼ 160$\^{C}$. Relationship among condition diagnosis tests was analyzed to find a dominative degradation factor and an insulation state at end-life point.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.763-766
• /
• 2000

In this paper, stator form-winding sample coils based on silicone resin and polyimide were made for fault prediction and reliability estimation on the 200 Class insulation system of traction motors. The complex accelerative degradation was performed by periods during 10 cycles, which was composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, condition diagnosis test such as insulation resistance & polarization index, capacitance & dielectric loss and partial discharge properties were investigated in the temperature range of 20∼160$^{\circ}C$. Relationship among condition diagnosis test was analyzed to find an dominative degradation factor and an insulation state at end-life point.

• 제어로봇시스템학회논문지
• /
• 제19권2호
• /
• pp.107-112
• /
• 2013

In this paper, we discuss a 3-dimensional localization sensor node using EM waves (Electromagnetic waves) with RSSI (Received Signal Strength Indicator). Generally EM waves cannot be used in underwater environment, because the signal is highly attenuated by the water medium according to the distance. Although the signal quickly reduces in underwater, the reducing tendency is very clear and uniform. Hence EM waves have possibility as underwater distance sensors. The authors have verified the possibility by theory and several experiments, and developed calibration methods in case of linear and planer environment. For 3-dimensional localization in underwater, it must be known antenna's radiation pattern property in electric plane(called E-plane). In this paper, we proceed experiments to verify attenuation tendency with z axis movement, PLF (Polarization Loss Factor) and ILF (Inclination Loss Factor) with its theoretical approach.