• Journal of Electrical Engineering and Technology
• /
• 제1권1호
• /
• pp.110-113
• /
• 2006

A high rate deposition sputtering process of magnesium oxide thin film in oxide mode has been developed using a 20 kW unipolar pulsed power supply. The power supply was operated at a maximum constant voltage of 500 V and a constant current of 40 A. The pulse repetition rate and the duty were changed in the ranges of $10\sim50$ kHz and $10\sim60%$, respectively. The deposition rate increased with rising incident power to the target. Maximum incident power to the magnesium target was obtained by the control of frequency, duty and current. The deposition rate of a moving state was 9 nm m/min at the average power of 1.5 kW. This result shows higher deposition rate than any other previous work involving reactive sputtering in oxide mode. The thickness uniformities over the entire substrate area of $982mm{\times}563mm$ were observed at the processing pressure of $2.8\sim9.5$ mTorr. The thickness distribution was improved at lower pressure. This technique is proposed for application to a high through-put sputtering system for plasma display panels.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
• /
• pp.268-270
• /
• 1995

In crane drives, DC motor has been most widely used due to simple control characteristic and favorable transient behavior. Nowadays, however, the squirrel cage induction motor is known as an attractive candidate due to elimination of all sliding electrical contacts, resulting in an exceedingly simple and rugged construction. Especially, in hoist application, the smooth torque control and four quadrant operation are essential. In this paper, an operation of dual inverters with common DC bus fed by vector controlled induction motor is described. Single DSP is employed as a main processor to control dual inverters and communicates each input/output signal with PLC. As well as giving a detailed expression, full simulation and experimental results are presented.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 초전도 자성체
• /
• pp.68-71
• /
• 2002

The electromagnetic properties and thermal behavior of ferrite cores used in the blocking filter for PLC were investigated as a function of additives. The highest density of 4.98 $g/cm^2$ and permeability of 8221 were obtained to the specimen added $MoO_3$ 400 ppm, $SiO_2$ 100 ppm and CaO 200 ppm since the microstructures were compacted through reduction of pores in the specimen. The permeability was increased up to 13094 at $110^{\circ}C$ with increasing temperature of specimen, however, it was decreased precipitously to under 100 over $110^{\circ}C$. The exothermic behavior was observed that the temperature of specimens became $102^{\circ}C$ at 1MHz. In the consequence, the ferrite core developed by this research will maintain the stable electromagnetic properties since the temperature of ferrite core rose to $93^{\circ}C$ in the range of 10kHz to 450kHz bandwidth qualified for PLC.

• 한국철도학회논문집
• /
• 제15권4호
• /
• pp.376-380
• /
• 2012

IPMSM의 구동 중에 발생되는 철손은 코어 재료 특성에 의해 크게 좌우되며, 일반적으로 회전형 전동기에서는 모든 자속의 흐름 방향으로 자기적 특성이 동일한 무방향성 전기강판이 코어 재료로 사용된다. 무방향성 전기강판과 비교하여 방향성 전기강판은 자속의 흐름 방향으로의 자기적 특성이 우수한 장점을 가지고 있다. 따라서 본 연구에서는 IPMSM의 철손을 저감시키기 위하여 코어 재료로써 무방향성 전기강판과 방향성 전기강판을 동시에 사용하는 구조를 제안하였다. IPMSM의 고정자에 자속 흐름의 방향으로 가공된 방향성 전기강판을 이용한 분할 티스 구조를 적용함으로써 기존의 110kW급 IPMSM과 비교하여 거의 40% 정도의 철손 저감 효과를 얻을 수 있었다.

• 농업생명과학연구
• /
• 제46권2호
• /
• pp.139-149
• /
• 2012

흑마늘과 개똥쑥을 반응표면분석법에 따른 중심합성계획에 의하여 $110{\sim}130^{\circ}C$와 2~4 시간 범위의 11가지 조건(A~K)에서 각각 열수추출하여 총 페놀, 플라보노이드 함량 및 항산화 활성이 최대화되는 추출조건을 모니터링 하였다. 항산화 활성의 정도에 따라 흑마늘 추출조건 3종($130^{\circ}C$, 4 hr; $120^{\circ}C$, 3 hr; $130^{\circ}C$, 3 hr)과 개똥쑥의 최적 추출조건 1종($120^{\circ}C$, 3 hr)을 선정하였다. 흑마늘 추출물에 대한 개똥쑥 추출물의 혼합비율을 1:0.5, 1:1, 1:1.5 및 1:2(w/w)로 조절하여 총 페놀, 플라보노이드 함량 및 항산화 활성을 측정한 결과, $120^{\circ}C$, 3시간에서 추출된 흑마늘 추출물과 개똥쑥 추출물의 혼합시 활성이 우수하였으며 최적의 혼합비율은 흑마늘과 개똥쑥 추출물에서 1:1.5(w/w)인 것으로 판단된다.

• 한국재료학회지
• /
• 제9권1호
• /
• pp.57-64
• /
• 1999

The electrical conductivity of TiO$_2$ doped with 0.05~1.5mol% WO$_3$ was measured in the oxygen partial pressure range of 10\ulcorner~10\ulcorner atm and temperature range of 1100~130$0^{\circ}C$ to investigate the defect types and the electrical properties. The grain size and density were increased as the liquid phase was formed by the doped WO$_3$. The secondary phase and WO$_3$peaks at the sample doped up to 4.0 mol% were not detected from the XRD results. The data(log$\sigma$/logPo$_2$) over 110$0^{\circ}C$ were divided into the four regions. From these experimental results, we proposed the following defect regions. 1) Magneli phase(extended defect), 2) Reduced rutile region which is similar to the behavior of undoped rutile, 3) Nearly stoichiometric Ti\ulcornerW\ulcornerO$_2$region in which extra charge of W\ulcorner cation is expected to be compensated by an electron, 4) Overstoichiometric Ti\ulcornerW\ulcornerO\ulcorner region which is a metal deficiency not to be observed in pure TiO$_2$. The electrical conductivity of w-doped TiO$_2$ was influenced by the measuring temperature, oxygen partial pressure, and the dopig content.

• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 1995년도 춘계학술발표회 초록집
• /
• pp.230-235
• /
• 1995

염-암모니아계 화학열펌프기술의 핵심인 전도성 블록의 특성파악을 위한 기초단계 연구로서 전도성 블록의 제조 및 기초물성분석에 관한 연구를 수행하였다. 황산이 함유된 천연흑연을 열처리하여 팽창흑연을 준비하고 특성을 분석하였다. 이 팽창흑연을 압축, 성형하여 흑연지지체를 제조하였으며, 성형된 지지체에 진공기법을 이용하여 염을 함침하고 건조과정을 거쳐 전도성 블록을 제조하였다. 전도성 블록의 특성분석으로서 염의 입자내에 분산정도는 EPMA/EDS, 기공율 및 기공크기 분포는 헬륨침투법과 수은 침투법, 기체투과도는 Darcy's law를 적용하고, 열전도도 측정은 전이 일차원 열류기법을 이용하였다. 전도성 블록이 암모니아와 반응 했을때 부피팽창을 관찰하였으며, 반응기에서 전도성블록의 온도분포를 관찰하였다. 본 연구에서 제조된 블록은 염이 균일하게 분산되어 있었으며 기공율은 제조조건에 따라 0.4 ∼ 0.83, 기체투과도는 0.01 ∼ 10 Darcy, 열전도도는 흑연지지체의 겉보기 밀도가 110 kg/㎥ 인 경우, 반지름방향의 열전도도, λr은 20 W/mK, 축방향의 열전도도, λa는 17 W/mK 이였다. 겉보기밀도가 150 kg/㎥ 인 경우, λr은 22 W/wK, λa는 20 W/wK 이였다. 전도성 블록의 부피팽창은 비가역적이었으며 대부분이 반지름 방향보다 축방향에서 팽창이 일어났다. 온도분포는 초기 반응의 kinetics가 내부온도를 지배하였으나, 시간이 경과후 반응기 내부온도는 외부열전달에 의해 지배되었다.

• 한국환경과학회지
• /
• 제8권3호
• /
• pp.293-297
• /
• 1999

Based on the monthly weather report of Korea Meteorological Administration (KMA) and daily sea surface temperature (SST) in Incheon harbor of National Fisheries Research and Development Institute, heat budget in Incheon coastal area was estimated. The temperature differences between the sea surface and near bottom were nearly within 1$^{\circ}C$. This indicate the mixing from the sea surface and the bottom. The net heat flux through the sea surface and the advection through the inner and outer bay was affected uniformly to the water body in Incheon coastal area. The net heat flux was about 110W/$m^2$ in maximum value on May, about -80W/$m^2$ in minimum on January. The net heat flux through the sea surface from the solar radiation was about 2.35$\times$${10}^5$W during the year. This heat flux flew out the bay through the advection by the same flux.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.1129-1131
• /
• 2001

A new low cost single stage high power factor electronic ballast for fluorescent lamps is presented in this paper. The proposed topology is based on integration of two-boost converter and LC type high frequency resonant converter. A ballast is obtained by simple construction, because full bridge rectifier diode is eliminated and simple control circuits is applied. Using two boost converter operating positive and negative half cycle respectively at line frequency (60Hz), operating in discontinuous conduction mode performs high power factor. The simulated and experimental results for 64W fluorescent lamps operating at 45kHz switching frequency and 110V line voltage have been obtained.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 A
• /
• pp.110-112
• /
• 2004

The outage management is very important because the outage causes a severe damage to the power system. Therefore, the utilities employ the outage management system, which is different from each others. This paper suggests the four kind of database systems for outage management. The efficiency of the outage management may be improved by using the suggested database system.