• Journal of Forest and Environmental Science
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• 제34권2호
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• pp.184-187
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• 2018

Characteristics of fecal sites of the Siberian flying squirrel Pteromys volans was analyzed based on 132 sites of total 19 places. The fecal sites were more frequently found in winter (43.9%), and then followed by autumn (27.3%), spring (23.5%), and summer (5.3%). With the exception of summer, the fecal sites were more frequently found at the root collar than on the forked tree (p<0.01). Among 132 fecal sites, 88 sites (66.7%) were found on the rood collars and the other 44 sites (33.3%) were posited in the forked trees. Brown or red clay pellets were found at 44 fecal sites (33.4%) and 43 fecal sites (32.6%), and then black and yellow pellets were at 22 fecal sites (16.7%) and 19 fecal sites (14.3%), respectively. Green pellets were rarely found only at 4 sites (3.0%). Feces tend to have bright colors (brown, red clay and yellow) in winter and black in summer. Fecal sites with yellow pellets were much less found in all of the three seasons with the exception of winter, but highly increased in 25.4% in winter. The fecal sites with brown (33.4%) and red clay pellets (32.6%) were most frequently found through the four seasons.

• Composites Research
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• 제14권3호
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• pp.77-89
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• 2001

초고속 일체형 주축의 공진주파수가 일체형 주축 시스템의 모터 회전자의 질량과 주축의 굽힘 강성에 의존하기 때문에 초고속 주축 시스템의 동적 특성을 향상시키기 위해 주축과 회전자를 각각 고분자 기지 섬유강화 복합재료와 자성분말이 함침된 에폭시 수지를 이용하여 설계하였다. 설계된 복합재료 회전자의 자기 특성을 향상시키기 위해 내부에 강철 코어를 삽입하였으며, 강철 코어와 전도체 봉의 기하학적 형상의 변화가 전동기의 성능에 미치는 효과를 파악하기 위해 자기 해석을 수행하였다. 유한요소해석을 통해 복합재료 회전자의 최적의 기하학적 조건을 제안하였다. 또한 복합 재료 회전자 재료의 열특성을 파악하기 위해 TMA, DMA및 VSM을 이용한 기계적, 전자기적 물성측정을 수행하여 복합재료 회전자의 최적 설계에 적용하였다.

• 조명전기설비학회논문지
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• 제28권1호
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• pp.57-68
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• 2014

This paper propose a development of squirrel-cage induction motor(IM) for 5-phase 1.5kW, 220V, 60Hz in order to study a polyphase ac machinery that keep hold of advantages more than traditional three-phase a IM, such as reducing a amplitude of torque pulsation, decreasing electric noises, and increasing the reliability. Designed methods of the motor use a development tools with Maxwell 2D and Simplorer program. There are designed drawing of manufactured frames of the IM. amplitude and waveform of the generated electromotive force, FFT analysis of harmonics within output voltages and current, and reviewing a experiment results are shown by variable output. We are presenting a design and manufacture methods for the 5-phase squirrel-cage IM.

• 한국정보통신학회논문지
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• 제12권1호
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• pp.122-129
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• 2008

기동 시나 갑작스런 토크명령 변동에 빠른 토크응답 특성을 갖는 퍼지 논리 제어기를 이용한 농형 유도 전동기의 직접 토크제어 방식을 제안하였다. 퍼지 제어 알고리즘은 기존의 DSC(Direct Self Controller) 제어 원리를 기저로 하여 제안하였으며 퍼지 추론 및 비 퍼지화를 거쳐 수행된다. 유도전동기의 자속과 토크는 광범위한 속도 영역에서 비 간섭 및 우수한 동특성을 갖는 회전자 자속 기준 동특성 모델을 사용하였다. 실험 결과 제시한 퍼지 제어 알고리즘은 우수한 동특성 및 적응적 특성을 갖으며 전동기 변수와 동작 조건의 변동에 민감하지 않고 강인하다.

• 한국기계연구소 소보
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• 통권14호
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• pp.73-91
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• 1985

• 대한전기학회:학술대회논문집
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• 대한전기학회 1986년도 하계학술대회논문집
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• pp.31-36
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• 1986

• 전기의세계
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• 제29권8호
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• pp.491-494
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• 1980

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1309-1312
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• 2002

The electric power network paralleled with wind turbine generator may have the negative impacts on the protection, operation, and management caused by the operation of wind turbine generator. Therefore, it is necessary to investigate the operating characteristic of wind turbine generator. This paper describes model of a squirrel-cage type wind turbine induction generator and the soft cut-in connection method for reducing the transient state on power network, and simulates various cases of wind turbine operations. The radial distribution network of IEEE 13-bus are modeled and tested by PSCAD/EMTDC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.188-190
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• 2006

This paper describes the effects of air gap eccentricity in induction machines. Asymmetric electro-magnetic force caused by the frictional worn bearing, rotor misalignment and unbalanced rotor etc. generates an asymmetrical operation, vibration and electro-magnetic noise. The need for detection of these rotor eccentricities has pushed the development of monitoring methods with increasing sensitivity and noise immunity. In this paper, we focus on investigating the asymmetrical operation considering of unbalanced magnetic force in squirrel-cage induction motor with 380 [V], 7.5 [kW], 4P, 1,768 [rpm]. The effects of the rotor eccentricity, magnetic force are investigated by finite element method (FEM).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.95-97
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• 2008

This Paper presents the effects according to broken rotor bar of squirrel cage induction motor. The rotor faults of induction motors may cause bad effects on the performance of the motor. An accurate modeling and analysis of characteristics of damaged rotor bar in the induction motor are developed using FEM(Finite Element Method). The results can be useful for real-time on-line monitoring system of an induction motor.