• 한국주조공학회지
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• 제33권6호
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• pp.248-253
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• 2013

To add alloying elements into a pure copper melt, the wire-feeding efficiency of cored (alloy containing) wire was evaluated using a commercial, computational fluid-dynamics program. The model design was based on an industrial-scale production line. The variables calculated included wire feed rate, melt temperature, wire diameter, melt flow rate and wire temperature. Efficiency was evaluated after a series of calculations based on the penetration depth of the alloy-wire into the molten copper bath. Of the five variables investigated, the wire feed rate and wire diameter were the most influential factors affecting the feeding efficiency of the cored-wire.

• 생태와환경
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• 제51권2호
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• pp.184-191
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• 2018

섭금류인 검은머리물떼새(Haematopus ostralegus osculans)는 주로 조수 경계부를 섭식지로 이용하는데, 번식기에는 간조시 드러난 갯벌에서 섭식하는 개체들이 일부 관찰된다. 드러난 갯벌에서 섭식하는 경우 조수 경계부에 비해 걸음수가 더 많고, 먹이탐색을 위해 중복탐침과 찔러넣기 행동의 비율이 더 높았지만, 섭식성공률은 현저히 낮았다. 또한, 주요 먹이원은 드러난 갯벌에서는 갯지렁이류였지만, 조수 경계부에서는 복족류(서해비단고둥)와 이매패류로 섭식지 유형간 뚜렷한 차이가 있었다. 번식기에 국한하여 드러난 갯벌을 섭식지로 이용하는 현상은 본래 선호하는 섭식지에 비해 효율이 떨어지더라도 번식 성공을 위해 번식지와 가까운 지역을 섭식지로 이용하는 것으로 판단된다. 본 연구는 번식이라는 생활사 변화에 맞춰 검은머리물떼새가 섭식행동과 먹이원을 달리함으로써 환경 변화에 대한 적응이 가능하다는 것을 제안한다.

• 전기학회논문지
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• 제64권4호
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• pp.634-639
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• 2015

In order to understand phenomenon of the electric railway power feeding system in the construction planning step, analysis of the overall system including electric characteristic of electric railway power feeding system, train running characteristic and power consumption pattern and train operation plan and gradients of railroad and curve radius is required. This paper study the feeder system by analysis of comprehensive system according to train operation plans, line impedance, running characteristic of train, electrical properties of the feeder system. In order to understand phenomenon to the feeder system of tram exactly regarding export of the field railroad preceeding actively recently.

• 한국전자파학회논문지
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• 제18권6호
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• pp.639-647
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• 2007

본 논문에서는 일반적인 평행 결합 선로 대역 통과 필터의 최외각 결합 선로를 K-인버터로 변환하고, K-인버터를 T-형 등가로 대체함으로써 직접 결합 급전 구조 대역 통과 필터를 구현하는 새로운 방법을 제안하였다. 이 방법은 기존의 외부 Q나 등가화 파라미터를 이용한 방법에 비해 매우 간단한 설계식을 제공하고, 특성의 적정화를 위한 노력과 시간을 상당히 줄일 수 있다. 제안한 이론에 의해 18%의 부분 대역폭을 갖는 직접 결합급전 구조 대역 통과 필터가 설계 및 제작되었고, 그 결과로부터 제안 방법의 타당성이 입증되었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 추계학술대회
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• pp.55-56
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• 2017

본 논문에서는 동일면 도파관(CPW; coplanar waveguide) 급전 방식을 이용하여 실내 디지털 TV(DTV)용 광대역 루프 안테나를 설계하였다. 제안된 루프 안테나는 정사각형 루프와 중앙 급전점을 연결하는 두 개의 원형 섹터로 구성되며, 아래쪽 원형섹터에 CPW 급전선로가 삽입된 형태이다. CPW 급전선로는 DTV응용을 위해 75옴 포트 임피던스와 정합하도록 설계되었으며, 중간 주파수 대역에서 임피던스 정합을 개선하기 위한 슬롯이 접지면에 추가되었다. 최적화된 안테나를 FR4 기판에 제작하고 특성을 실험한 결과, 전압 정재파비(VSWR; voltage standing wave) < 2인 대역이 463-1,280 MHz으로 DTV 대역에서 동작하는 것을 확인하였다.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.720-720
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• 2006

• 한국군사과학기술학회지
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• 제9권1호
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• pp.144-151
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• 2006

A rectangular loop antenna for S-band radar is proposed. The proposed loop antenna is the modified type of folded monopole antenna. The feeding line is coplanar stripline with $180^{\circ}$ phase difference for operating in odd mode. The proposed antenna showed return loss of -15.57dB at the center frequency and bandwidth of about 790MHz (> 25%) under the condition of VSWR < 2. The gains of single, 1x2, and 1x4 array loop antennas are 4.3, 7.0, and 10.2dBi, respectively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.490-496
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• 2002

This paper presents exact Autotransformers(ATs)-fed AC electric Railroad system modeling using constant current mode far locomotives. An AC electric railroad system is rapidly changing single-phase load, and at a feeding substation, 3-phase electric power is transferred to paired directional single-phase electric power. As the train moves along a section of line between two adjacent ATs. The proposed AC electric railroad system modeling method considers the line self-impedances and mutual-impedances. The constant current mode model objectives are to calculate the catenary and rail voltages with the loop equation. When there are more than one train in the AC electric railroad system, the principle of superposition applies and the only difference between the system analyses for one train. Finally, this paper shows the general equation of an AC electric railroad system, and that equation has no relation with trains number, trains position, and feeding distance.

• 대한전기학회논문지:전력기술부문A
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• 제52권9호
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• pp.493-499
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• 2003

This paper presents exact Autotransformers(ATs)-fed AC electric Railroad system modeling using constant current mode for locomotives. An AC electric railroad system is rapidly changing single-phase load, and at a feeding substation, 3-phase electric power is transferred to paired directional single-phase electric power. As the train moves along a section of line between two adjacent ATs. The proposed AC electric railroad system modeling method considers the line self-impedances and mutual-impedances. The constant current mode model objectives are to calculate the catenary and rail voltages with the loop equation. When there are more than one train in the AC electric railroad system, the principle of superposition applies and the only difference between the system analyses for one train. Filially, this paper shows the general equation of an AC electric railroad system, and that equation has no relation with trains number, trains position, and feeding distance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.682-687
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• 2005

High quality power supplying of power distribution system in electric railway system is the important function. Power feeding system is complicated witch is compose with distribution line, circuit break, protection facilities and so on. Among this components, role of substation is most important for elevation of reliability in electric power system. Therefore, the enhanced reliability considering the preventive inspection, repair work, replacement is necessary. In this study, a proposed the enhanced reliability method through a calculation of fault probability in power feeding system.