• Journal of Advanced Marine Engineering and Technology
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• 제24권5호
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• pp.42-51
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• 2000

The performances of the simple expansion, perforated tube, and conical-connector type as an exhaust muffler are shown in this study. Applying a model in which the method of four-pole parameter is used makes theoretical estimation of the insertion loss. Experiment is performed for the measurement of the insertion loss under four cases according to the variation of the tail pipe length. By comparing the theoretical prediction with the experimental results, the validity of the modeling using the method of four-pole parameter is verified. The personal computer simulation programs for the above mentioned theory on the muffler design have been developed and exhaust sound level measurements have been carried out for simple expansion muffler, conical-connector muffler, perforated tube mufflers and the combined type of conical-connector and simple expansion muffler. The measured results for attenuation characteristics of noise for each muffler are compared with the computed theoretical results to verity the confidence and applicable limits of the theoretical equation derived.

• Journal of Magnetics
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• 제18권2호
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• pp.207-211
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• 2013

In a coaxial magnetic gear, bridges connecting separate pole pieces are useful for fabrication and also improve mechanical reliability. However, they have a negative influence on electromagnetic performance parameters such as transmission torque and iron loss. This paper investigates the effect of stationary pole pieces connected by bridges on the electromechanical characteristics. The bridge type and thickness are the main parameters influencing the performance of a coaxial magnetic gear. The inner, center, and outer bridge types each show the best performance in terms of different characteristics. However, for any bridge type, an increase in the bridge thickness reduces the overall electromagnetic performance, except for the torque ripple, and improves the overall mechanical performance, including the deformation, von Mises stress, and natural frequency of the stationary part.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.749-751
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• 2004

This paper analyzed the characteristics of the claw pole PM step motor by using 3D FEM. In case of analysing this type of motor, 3 dimensional analysis is necessary for an accurate analysis due to the magnetizing component of the z-axis direction. As a main design variable, the magnetization, width and the effects of skewing was selected. The variation of the detent torque and the back EMF depending on the shape of the pole is also shown.

• Journal of Power Electronics
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• 제16권1호
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• pp.48-56
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• 2016

This paper proposes a method for detecting irreversible demagnetization using the harmonic analysis of back electromotive force (BEMF) in interior permanent magnet-type brushless DC motors. First, demagnetization patterns, such as equality, inequality, and weighted demagnetizations, are defined and classified by considering the possibility of demagnetization resulting from motor operating characteristics. Second, an available diagnostic model for the harmonic analysis of BEMFs is defined according to pole-slot coefficients because the characteristics of BEMFs under demagnetization conditions are affected by the combination of poles and slots. Third, BEMFs and their harmonic components under normal and demagnetization conditions are analyzed through simulation and experiment to verify the proposed demagnetization detection technique.

• 전기학회논문지
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• 제56권8호
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• pp.1441-1444
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• 2007

This paper presents a novel electrostatic drop-an-demand ejector with a conductive pole inside nozzle. The MEMS fabricated pole-type nozzle shows a significant improvement in the performance and reliability of forming meniscus and generating a micro dripping mode of droplet out of the meniscus. It is verified experimentally that the use of the pole-type nozzle. The liquid is used D20+SDS+SWNT (5 %wt). The gap between upper electrode and nozzle is about 600 um. Electrostatic drop-an-demand ejection is observed when a DC voltage of 1.5 kV is applied between the control electrode and ground electrode. Droplet diameter is $100{\mu}m$.

• 한국초전도ㆍ저온공학회논문지
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• 제10권3호
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• pp.14-18
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• 2008

This paper deals with the conceptual design and characteristic analysis of core type superconducting motor using iron cores in the field. As the objective function of conceptual design, the flux quantity per pole is selected. In order to reduce the quantity of superconductors, the variations of flux quantity per pole by changing the design variables and area are investigated. Finally, the quantity of superconductors between air-cored and core type superconducting motor is compared under the same motor capacity. In addition, the dimensions and volumes of motors are compared.

• 한국전자파학회논문지
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• 제16권6호
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• pp.594-602
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• 2005

본 논문에서는 결함 접지 구조(Defected Ground Structure, DGS)를 이용하여 설계한, 전송 선로의 폭이 매우 넓어진 새로운 형태의 5-단 저역 통과 여파기(5-pole Low Pass Filters, LPF)를 제시한다. 이를 위하여 종래에 제시 되었던 3-단 DGS LPF설계 방법을 임의의 N-단 LPF설계에도 적용할 수 있도록 일반화 시키고$(N\geq5)$, 한 예로써 5-단 LPF를 설계 및 측정 결과가 제시된다. LPF원형 회로로부터 필요한 소자값들을 갖는 서로 다른 크기의 DGS를 결정하기 위하여, 매우 정확한 인덕턴스 값을 예측해 주는 곡선 맞춤(curve-fitting) 방법도 제시되었다. 제안하는 5-단 LPF는 병렬 캐패시턴스 구현을 위해 개방 스터브 대신 선폭이 크게 보상된 낮은 임피던스의 전송 선로를 갖는다. 따라서 개방 스터브를 사용할 때 필수적으로 요구되는 T-나 Cross-불연속 접합 소자가 없고, 또한 기존의 LPF에서 직렬 인덕턴스 때문에 필요했던 높은 임피던스 전송 선로가 없다.

• Journal of Trauma and Injury
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• 제26권3호
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• pp.218-221
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• 2013

A patella sleeve fracture is a type of avulsion fracture in which a small osseous fragment gets, along with a sleeve of periosteum and cartilage, is pulled off from the patella. The avulsed sleeve of cartilage and periosteum is not apparent on plain radiographs, which can result in a missed diagnosis or an underestimate of the extent of injury. An avulsion or sleeve fracture of the patella in a child can occur at the superior or the inferior pole of the patella. However, most reported cases of sleeve fractures involve the inferior patellar pole, with fractures involving the superior patellar pole being very rare. The authors report a case of a sleeve fracture of the superior pole of the patella in an adolescent; the fracture was diagnosed with magnetic resonance imaging (MRI) and was treated with surgery after early diagnosis. The course was uneventful, and the outcome was excellent.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.936-939
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• 2004

In this paper a comparison of the initial rotor position estimation methods by two type search coils for switched reluctance motor(SRM) is presented. The experimental results of the two methods show that the interior central pole search coil method has better performance than the exterior pole search coil method. The reason of the discrepancy in performance is described.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.431-433
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• 1997

In this paper, we consider the robust pole assignment inside the circular region for linear systems with time-varing uncertainty. The considered uncertainties are the norm bounded uncertainty and the matrix polytopes type uncertainty. Since the considered uncertainties are time-varying, it should remind that the closed loop system be time-varing system. Therefore, we should consider not only the pole assignment but also the stability. We present new conditions that guarantee the robust pole assignment and the robust stability. Finally, we show the usefulness of our results by an example.