• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.282-289
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• 2010

A Thomson coil type actuator is applied as the driving unit in an arc eliminator system. To eliminate the arc efficiently, the speed of the actuator is required as fast as possible with certain limit of the exciting current. Therefore, the dynamic characteristics of the Thomson coil type actuator should be analyzed in an effective way. In this paper, a novel solving technique has been developed based on the equivalent circuit model which is set up by dividing the conducting plate into multi segments. To guarantee the calculation accuracy and improve the calculation efficiency, an adaptive refinement algorithm is suggested based on the field continues condition. The proposed method has been verified by the FEM calculation and experiment. The influence of circuit and plate parameters to the performance of the actuator is also investigated, from which a reasonable set of parameters can be found.

• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.86-90
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• 2007

The cryoprobe used in cryosurgery should be fabricated in milimeter-order size for its practical usage. In general a miniature J-T(Joule-Thomson) refrigerator is applied to a cryoprobe. In case of the miniature J-T refrigerator, the mass flow rate of working fluid is small due to considerable friction in a minute flow path. For that reason, the miniature J-T refrigerator has a limited cooling power. To obtain the large cooling power from the J-T refrigerator, the refrigerator should have large mass flow rate and effective J-T temperature drop. These quantities are closely related to the geometry of the heat exchanger and the expansion nozzle in a cryoprobe, and are contradictory. The large mass flow rate leads to the small J-T temperature drop and vice versa in the miniature J-T refrigerator. Therefore, the optimal design of a cryoprobe to achieve maximum cooling power at fixed tube size and fixed operating temperature is required. This paper presents the design procedure of such case.

• 한국항행학회논문지
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• 제13권3호
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• pp.378-384
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• 2009

본 논문에서는 주파수 사용 효율 증대를 위한 사이클로스테이션너리 특징 검출 (Cyclostationary Feature Detection; CFD)방식의 ATSC 신호 검출 알고리듬을 고려한다. 현재 IEEE 802.22 표준화 기구에 제안된 알고리듬들 중 IEEE 802.22의 권고사항을 충분히 만족시키는 알고리듬으로 사이클로스테이션너리 특징 검출 방식에 기반한 톰슨(Thomson)사의 알고리듬이 있다. 본 논문에서는 톰슨사의 알고리듬보다 계산량이 적으면서 톰슨사의 알고리즘의 성능에 필적할 만한 성능을 갖는 보간법 기반 ATSC 스펙트럼 센싱 알고리듬을 제안한다. 제안하는 보간법 기반 알고리듬은 시간영역에서의 영삽입(Zero-Padding) 방법과 효과적인 센싱 스캔 방법을 사용하여 적은 계산량으로 톰슨사의 성능에 필적하는 성능을 보여준다.

• 천문학회지
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• 제40권1호
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• pp.1-7
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• 2007

About 10 percent of quasars are known to exhibit deep broad absorption troughs blueward of prominent permitted emission lines, which are usually attributed to the existence of outflows slightly above he accretion disk around the supermassive black hole. Typical widths up to 0.2c of these absorption roughs indicate the velocity scales in which special relativistic effects may not be negligible. Under he assumption of the ubiquity of the broad absorption line region in quasars, the broad emission line flux will exhibit Thomson scattered components from these fast outflows. In this paper, we provide our Monte Carlo calculation of linear polarization of singly Thomson scattered line radiation with the careful considerations of special relativistic effects. The scattering region is approximated by a collection of rings that are moving outward with speeds ${\upsilon}=c{\beta}<0.2c$ near the equatorial plane, and the scattered line photons are collected according to its direction and wavelength in the observer's rest frame. We find that the significantly extended red tail appears in the scattered radiation. We also find that the linear degree of polarization of singly Thomson scattered line radiation is wavelength-dependent and hat there are significant differences in the linear degree of polarization from that computed from classical physics in the far red tail. We propose that the semi-forbidden broad emission line C III]1909 may be significantly contributed from Thomson scattering because this line has small resonance scattering optical depth in the broad absorption line region, which leads to distinct and significant polarized flux in this broad emission line.

• 한국가스학회지
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• 제21권1호
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• pp.72-79
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• 2017

극한지 천연가스 배관의 운전온도 범위는 가스 공급을 최적화하고 운전동안 극한지 환경에 대한 충격을 최소화하기 위해 기본적으로 제어되어야 한다. 배관에 흐르는 가스의 온도는 Joule-Thomson 효과와 배관과 토양의 열전달에 의존한다. 따라서 본 연구에서는 매설 천연가스 배관의 열전달과 Joule-Thomson 효과를 상세히 고려하였다. 토양온도는 $0{\sim}-20^{\circ}C$, 총괄열전달계수는 $0{\sim}5.5W/m^2K$로 가정하였다. 토양온도와 총괄열전달계수 변화에 따른 배관 길이방향의 가스온도 변화와 압력손실을 동시에 계산하였다. 또한, 본 연구에서는 HYSYS 프로그램을 사용하여 토양온도와 총괄열전달계수에 따른 상변화와 하이드레이트 생성을 예측하였다.

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권4호
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• pp.107-112
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• 2001

Laser Thomson scattering measurements of electrom temperature and density in a neutral loop discharge (NLD) plasma were performed in order to reveal the electron behavior around the neutral loop (NL). The experimental results were examined by using a simulation model that included effects of a three dimensional electromagnetic field with spatial decay of the RF electric field, and the limitation of the spatial extent of the electron motion and collision effect. From the experiments and modeling of the electron behavior, it was found that NLD plasma posses the electron temeprature $T_{e}$ and density ne peaks around the NL is essential for the formation of plasma. Also, the optimum condition of plasma production could be simply estimated by the calculation of $U_{av}$ and $F_{0}$././.

• 한국응용곤충학회지
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• 제55권2호
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• pp.103-107
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• 2016

한국산 꼬마검정물땡땡이속(Paracymus Thomson)의 분류학적 연구를 수행하였다. 꼬마검정물땡땡이속, 염전꼬마검정물땡땡이[P. aeneus (Germar)]와 꼬마검정물땡땡이(P. zaitzevi Shatrovskiy)를 한반도에서 처음 보고한다. 종에 대한 성충의 외형 과 주사전자현미경 사진, 분포도, 식별 형질 및 검색표를 제시한다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.182-188
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• 2017

An arc eliminator allows a surge current bypass rapidly into the earth to facilitate the circuit breaking process and increase the stability of the load circuit. Thomson coil actuator (TCA) is a type of actuator that can function as an arc eliminator. The TCA has a simple structure and significantly rapid speed compared to the other types of actuators. In this paper, significant variables, which have a dominant effect on the performance of the TCA, are investigated in detail. Using these variables and an optimization algorithm, an optimal design strategy for the TCA is proposed in this research. The efficacy of the proposed optimal design strategy and the feasibility of the application of the designed TCA for a high power circuit breaker as the arc eliminators are validated through the experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.772_773
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• 2009

A numerically efficient performance analysis method for Thomson coil actuator of an arc eliminator is developed by transferring the problem to an equivalent circuit model considering the distribution of eddy current in conducting plate. Through a numerical analysis, the developed method is proven to give a solution, with only 1.3% of computing time, as accurate as finite element method. The developed method is testified by comparing with FEM calculation and experiment results.

• 한국응용곤충학회지
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• 제54권1호
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• pp.25-30
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• 2015

한국산 미기록 속인 뚱보바수염반날개속(Thamiaraea Thomson) (신칭)의 2종-큰뚱보바수염반날개(T. diffinis Sharp) (신칭)와 뚱보바수염반날개(T. japonica Cameron) (신칭)-을 한반도에서 처음으로 보고한다. 이 2종에 대한 검색표, 재기재, 및 식별형질에 대한 그림을 제시한다.