• 한국컴퓨터정보학회논문지
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• 제17권2호
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• pp.87-94
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• 2012

기계적 제동방식이 사용되는 전동차는 공기제동과 전기제동을 혼합한 방식으로 최근 녹색성장을 지향하면서 효율개선 및 환경문제 해결을 위한 많은 방법들이 제시되고 있다. 기계적인 제동은 분진, 소음 등의 환경문제와 함께 브레이크 슈와 라이닝 등의 소모품을 교체해야하는 경제적 문제를 가지고 있다. 이러한 단점을 보완하기 위하여 고속 영역에서 정지에 이르는 광범위한 영역에 이르기까지의 전기제동을 필요로 하게 되었다. 본 연구는 구배에 의한 부하토오크를 추정하여 전동차를정지시키는방법에대해연구되어졌으며낙차에따른 토오크를 추정하여 제동하는 방법의 특성을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제7권2호
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• pp.151-156
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• 2012

The current study presents a zero-one integer programming approach to determine the minimum break point set for the coordination of directional relays. First, the network is reduced if there are any parallel lines or three-end nodes. Second, all the directed loops are enumerated to reduce the iteration. Finally, the problem is formulated as a set-covering problem, and the break point set is determined using the zero-one integer programming technique. Arbitrary starting relay locations and the arbitrary consideration of relay sequence to set and coordinate relays result in navigating the loops many times and futile attempts to achieve system-wide relay coordination. These algorithms are compared with the existing methods, and the results are presented. The problem is formulated as a setcovering problem solved by the zero-one integer programming approach using LINGO 12, an optimization modeling software.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.376-377
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• 2009

In the study the affect of $SiO_$ depending on the characteristics of break-down, we have experimented the break-down for the $SiO_$ and variable temperature change after mading nano $SiO_$ of the diameter 12 [nm] at the epoxy resin. As the experimental results, we have continued that the break-down strength is increased at the adding change but the break-down strength is decreased again as the 0.4 [wt%] standard. Also, the break-down voltage is not changed at 25, 50 [$^{\circ}C$] as the temperate change. But break-down voltage is largely changed when temperate is rising up.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.241-241
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• 2009

For the Radio Frequency Integrated Passive Device (RFIPD) application, we have successfully developed and characterized high break-down voltage metal-insulator-metal (MIM) capacitors with 2,000 ${\AA}$ plasma-enhanced chemical vapor deposition (PECVD) silicon nitride which deposited with $SiH_4/NH_3$ gas mixing rate, working pressure, and RF power of PECVD at $250^{\circ}C$ chamber temperature. At the PECVD process condition of gas mixing rate (0.957), working pressure (0.9 Torr), and RF power (60 W), the AFM RMS value of about 2,000 ${\AA}$ silicon nitride on the bottom metal was the lowest of 0.862 nm and break-down electric field was the highest of about 8.0 MV/cm with the capacitance density of 326.5 $pF/mm^2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.360-361
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• 2005

Rapid progress in IC fabrication technology has strong demand in polishing of silicon wafer to meet the tight specification of nanotopography and surface roughness. One of the important issues in Si CMP is the stabilization of polishing pad. If a polishing pad is not stabilized before main Si wafer polishing process, good polishing result can not be expected. Therefore, new pad must be subjected into break-in process using dummy wafers for a certain period of time to enhance its performance. After the break-in process, the main Si wafer polishing process must be performed. In this study, the characteristics of break-in process were investigated in Si wafer polishing. Viscoelastic behavior, temperature variation of pad and friction were measured to evaluate the break-in phenomenon. Also, it is found that the characteristic of the break-in seems to be related to viscoelastic behavior of pad.

• 화약ㆍ발파
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• 제36권1호
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• pp.34-38
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• 2018

철도터널 발파 시 근접한 보안물건에 대하여 발파진동 및 소음을 제어하고, 여굴방지를 목적으로 전자뇌관과 비전기뇌관을 조합한 발파시스템(Supex Blasting Method)을 적용하여 보성~임성리 ${\bigcirc}{\bigcirc}$ 철도건설공사에서 시험발파를 실시하였다. 그 결과 발파진동과 소음은 허용기준치 이내로 측정된 것으로 나타났다. 결과적으로 전자뇌관과 비전기뇌관을 조합한 터널발파 시스템은 공사비 절감, 발파진동 및 소음제어를 통한 민원방지 효과 및 여굴제어로 굴착예정선 주변의 암반손상권을 최소화하는 것으로 나타났다.

• 한국전기전자재료학회논문지
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• 제21권2호
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• pp.104-110
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• 2008

In this paper we proposed a new source-drain structure for N-type MOSFET which can suppress the output resistance reduction of a device in saturation region due to soft break down leakage at high drain voltage when the gate is biased around relatively low voltage. When a device is generally used as a switch at high gate bias the current level is very important for the operation. but in electronic circuit like an amplifier we should mainly consider the output resistance for the stable voltage gain and the operation at low gate bias. Hence with T-SUPREM simulator we designed devices that operate at low gate bias and high gate bias respectively without a extra photo mask layer and ion-implantation steps. As a result the soft break down leakage due to impact ionization is reduced remarkably and the output resistance increases about 3 times in the device that operates at the low gate bias. Also it is expected that electronic circuit designers can easily design a circuit using the offered N-type MOSFET device with the better output resistance.

• 전력전자학회논문지
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• 제23권5호
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• pp.299-304
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• 2018

An ideal circuit breaker should supply electric power to loads without losses in a conduction state and completely isolate the load from the power source by providing insulation strength in a break state. Fault current is relatively easy to break in an Alternating Current (AC) circuit breaker because the AC current becomes zero at every half cycle. However, fault current in DC circuit breaker (DCCB) should be reduced by generating a high arc voltage at the breaker contact point. Large fire may occur if the DCCB does not take sufficient arc voltage and allows the continuous flow of the arc fault current with high temperature. A semiconductor circuit breaker with a power electronic device has many advantages. These advantages include quick breaking time, lack of arc generation, and lower noise than mechanical circuit breakers. However, a large load capacity cannot be applied because of large conduction loss. An extinguishing technology of DCCB with polymeric positive temperature coefficient (PPTC) device is proposed and evaluated through experiments in this study to take advantage of low conduction loss of mechanical circuit breaker and arcless breaking characteristic of semiconductor devices.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.61-64
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• 2000

Three kinds of treeing inhibitors are added to investigate the effect on electrical properties of XLPE. The treeing inhibitors are barbituric acid, 4- (4-Nitrophenylazo) resorcinol and 4-(4-Nitrophenylazo) naphthol. Added amount of each treeing inhibitors varied form 0phr to 2.0phr. In order to know the changes of electrical properties, break down strength, tan$\delta$, and $\varepsilon$$_{r}$ were measured. Experimental results showed that electrical properties of each sample was slightly changed by amount of additives.s.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.169-172
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• 2000

In this paper, we evaluated the mechanical and dielectric properties of LDPE depend on $Co_{60}$${\gamma}$-irradiation doses. The chemical analyses for FT-IR, gel content, the mechanical properties for elongation at break and the dielectric parameters for permittivity, tan$\delta$ were discussed as a function of irradiation doses. Test result presented that elongation at break of irradiated LDPE was inversely proportional to gel content. For dielectric analyses, permittivity showed a salient characteristic for various irradiation doses, it was related to polar groups caused radiation degradation and tan$\delta$ of irradiated LDPE increased with irradiation doses.