• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.628-630
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• 1995

CT saturation may cause protective relays to malfunction. The conventional method to deal with the problem is overdimensioning of the core so that CTs can carry up to 20 times the rated current without exceeding 10 % ratio correction. However, this not only reduces the sensitivity of relays, but also increases the CT core size. This paper presents a technique of estimating the secondary current corresponding to the CT ratio under CT saturation using the magnetization curve. The proposed algorithm can improve the sensitivity of relays to low level faults and minimize the instability of relays for external faults.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.28-30
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• 1998

In the case of long secondary (applied in long distance), as it is established horizontal, the defects of droop arises resulting damage of entire system. Actually, it is difficult to expect reasonable characteristics and desirable operating in that case. This paper is about numerical analysis of secondary droop, non-symmetric and position displacement problems. In the base of this paper, the correction of mechanical difficulties in practical manufacturing and optimal design of TLIM considering these aspects can be progressed successively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.920-922
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• 2004

This paper presents a speed control system for a linear induction motor(LIM) with cage-type secondary using direct thrust control(DTC). The actual speed of the LIM is detected by the linear scale with the resolution of $100{\mu}m$. Thrust correction coefficient due to the end effect of the LIM is utilized in estimating actual thrust. As a result, responses of the thrust, current, speed, and flux are shown.

• Applied Microscopy
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• 제51권
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• pp.19.1-19.7
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• 2021

The main purpose of this paper is the preparation of transmission electron microscopy (TEM) samples from the microsized powders of lithium-ion secondary batteries. To avoid artefacts during TEM sample preparation, the use of ion slicer milling for thinning and maintaining the intrinsic structure is described. Argon-ion milling techniques have been widely examined to make optimal specimens, thereby making TEM analysis more reliable. In the past few years, the correction of spherical aberration (Cs) in scanning transmission electron microscopy (STEM) has been developing rapidly, which results in direct observation at an atomic level resolution not only at a high acceleration voltage but also at a deaccelerated voltage. In particular, low-kV application has markedly increased, which requires a sufficiently transparent specimen without structural distortion during the sample preparation process. In this study, sample preparation for high-resolution STEM observation is accomplished, and investigations on the crystal integrity are carried out by Cs-corrected STEM.

• 대한구순구개열학회:학술대회논문집
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• 대한구순구개열학회 2003년도 종합학술대회
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• pp.33-33
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• 2003

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.401-404
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• 1998

This paper proposes a new soft switching single stage AC/DC full bridge converter with unit power factor and isolated output. This circuit shows that it is possible to combine the boost converter which is for PFC(Power Factor Correction) and full bridge converter which is for DC/DC converter. A simple auxiliary circuit which includes neither lossy components nor active switches eliminates ringing of secondary side of the transformer. The characteristics of the proposed circuit are investigated and the validity is verified by the simulation results.

• 대한구순구개열학회:학술대회논문집
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• 대한구순구개열학회 1997년도 종합학술대회
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• pp.37-37
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• 1997

• IEIE Transactions on Smart Processing and Computing
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• 제6권3호
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• pp.200-209
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• 2017

In this paper, we investigate the tradeoff between security and reliability for a multi-hop protocol in cluster-based underlay cognitive radio networks. In the proposed protocol, a secondary source communicates with a secondary destination via the multi-hop relay method in the presence of a secondary eavesdropper. To enhance system performance under the joint impact of interference constraint required by multiple primary users and hardware impairments, the best relay node is selected at each hop to relay the source data to the destination. Moreover, the destination is equipped with multiple antennas and employs a selection combining (SC) technique to combine the received data. We derive closed-form expressions of the intercept probability (IP) for the eavesdropping links and the outage probability (OP) for the data links over a Rayleigh fading channel. Finally, the correction of our derivations is verified by Monte-Carlo simulations.

• 한국진공학회지
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• 제10권2호
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• pp.225-233
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• 2001

Oxygen flooding을 이용한 Secondary ion Mass Spectrometry(SIMS) 분석에 있어서 표면에 산화막이 있을 때 발생하는 SIMS depth profile의 왜곡현상에 대한 원인을 분석하고 이를 보정하였다. 이러한 왜곡현상은 표면 산화막에서와 Si 매질에서의 sputter rate이 다른 데서 발생하는 깊이 보정 오류와 상대감도인자(relative sensitivity factor, RSF)가 다른 데서 발생하는 농도보정 오류로부터 발생됨이 밝혀졌다. 깊이보정 오류를 바로잡기 위하여 $N^a+$ 이온을 산화막과 Si 매질의 계면에 대한 marker로 사용하였으며 산화막 두께는 SEM 및 XPS로 측정하였다. 산화막과 Si 매질에서의 sputter rate 및 RSF의 차이는 주로 oxygen flooding이 유발한 산화막 형성시의 부피팽창에 의한 것으로 해석되었으며 이를 보정한 depth profile은 oxygen flooding없이 분석한 경우와 거의 동일한 결과를 보여주었다.

• 대한두개안면성형외과학회지
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• 제9권1호
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• pp.12-16
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• 2008

Purpose: Closed reduction is most common treatment method for nasal bone fracture but it requires secondary correction operation commonly. For preventing secondary revision, we applied ultrasonography during closed reduction of nasal bone fracture and examined the result of operation. Methods: 80 patients were sorted into 2 groups, ultrasound-guided closed reduction group(n=40) and manual closed reduction group(n=40). We classified the unilateral fracture involving lower 1/2 of nasal bone into type I, the bilateral fracture involving lower 1/2 of nasal bone into type III and the fracture of upper 1/2 of nasal bone into type III. The occurrence rate of overcorrection and undercorrection were evaluated by comparing preoperative and postoperative MDCT(Multi Direction Computed Tomography). Results: In manual closed reduction group, overcorrection were found in 4 patients and undercorrection were found in 3 patients. In ultrasound-guided closed reduction group, overcorrection was not observed and undercorrection was observed in 2 patients. Conclusion: Intraoperative ultrasound evaluation of nasal bone fracture resulted in reduced occurrence rate of secondary nasal deformities, showed easier detection of the fractured site and have superiority upon simple physical examination or simple x-ray.