• 한국음향학회지
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• 제20권6호
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• pp.82-86
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• 2001

본 논문에서는 평행한 이중 선 배열을 위한 합성 기법을 제안하고자 한다. 일반적으로 천해에서 사용되는 단일 배열은 신호의 이득을 높이고 각 분해능을 높이기 위해서 긴 어퍼쳐 길이를 요구하고 있다. 그러나 원거리로부터 발생한 극 저주파 신호는 수신단에서 어레이를 기준으로 좌, 우 모호성을 드러낸다. 이러한 문제점을 해결하기 위해 평행한 이중 선 배열을 이용하면서 합성 기법을 적용하였다. 어레이 합성 기법은 연속적인 시간에서 얻어진 각각의 데이터들을 빔 영역에서 코히어런트한 합성을 거쳐 공간 영역에서 가상의 어레이로 확장하였다. 제안된 방법은 인접한 다중 음원 환경에서의 각도 오차를 줄이고 어레이 합성 횟수에 따라 향상된 분해능성능을 나타내었다. 시뮬레이션 결과 어레이 합성 기법을 적용하기 전과 5회의 합성을 수행했을 경우, 평균 부엽 레벨은 약 7dB가 향상되었다.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.222-226
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• 1990

This paper represents the construction of laser beam writing system, laser lithography, using new method that guarantees convenience and accuracy in laser focusing. The X, Y translation stage using DC motors was controlled by the computer. Minimum line width of 1.6${\mu}{\textrm}{m}$ was obtained by the laser lithography system.

• 한국광학회:학술대회논문집
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• 한국광학회 2007년도 하계학술발표회 논문집
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• pp.151-152
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• 2007

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.956-957
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• 2005

• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 하계학술발표회 논문집
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• pp.345-346
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• 2006

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.805-806
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• 2005

• 한국전자파학회논문지
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• 제22권8호
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• pp.754-760
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• 2011

본 논문에서는 직물형 회로 기판상에 설계된 U-슬롯을 갖는 빔 조향(beam steering) 마이크로스트립 패치(microstrip patch) 안테나를 제안하였다. 본 안테나는 직물형 회로 기판 및 의복상에 제작하는 것을 목적으로 설계되었으며, 동작 주파수 6.0 GHz에서 빔 조향이 가능하도록 설계되었다. 빔 조향을 위해 U-슬롯과 간접적 급전(in-direct feed) 방식이 적용되었으며, 안테나 패치 부분과 간접 급전부 사이에 두 개의 가상 스위치(line connection)을 이용하였다. 두 개의 가상 스위치 조합($S_0$, $S_1$, $S_2$)에 따라, 최대 빔 방사 방향은 yz-평면상에서 ${\theta}=0^{\circ}$, $30^{\circ}$, $331^{\circ}$, 세 방향으로의 빔 조향이 가능하다. 전체 반전력 빔 폭(HPBW)에 의한 빔 커버리지는 약 $115^{\circ}$이고, 빔 조향시 6.11~6.69 dBi의 최대 이득(peak gain)을 갖는다.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1253-1260
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• 2022

This paper reports the control method for the core power of the China initiative Accelerator Driven System (CiADS) facility. In the CiADS facility, an intense external neutron source provided by a proton accelerator coupled to a spallation target is used to drive a sub-critical reactor. Without any control rod inside the sub-critical reactor, the core power is controlled by adjusting the proton beam intensity. In order to continuously change the beam intensity, an adjustable aperture is considered to be used at the Low Energy Beam Transport (LEBT) line of the accelerator. The aperture size is adjusted based on the Proportional Integral Derivative (PID) controllers, by comparing either the setting beam intensity or the setting core power with the measured value. To evaluate the proposed control method, a CiADS core model is built based on the point reactor kinetics model with six delayed neutron groups. The simulations based on the CiADS core model have indicated that the core power can be controlled stably by adjusting the aperture size. The response time in the adjustment of the core power depends mainly on the adjustment time of the beam intensity.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권3호
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• pp.289-295
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• 2005

Instrumentation and Control (I&C) of the Neutral Beam Test Stand (NB- TS) Facility at the Korea Atomic Energy Research Institute (KAERI) for the Korea Superconducting Tokamak Advanced Research (KSTAR) project has been underway since the start of the project to answer the diverse requests arising from the various facets of the development and construction phases of the project. Optical signal transmission constitutes a significant portion of I&C works and has been performed for the entirety of the project. During the NB- TS construction and related experiments, significant achievements to a more accurate as well as more refined optical signal transmissions have been made. Examples of those I&C works that utilized the optical signal transmission are the Langmuir probe signal transmission, gradient grid current signal transmission, gas flow control and signal transmission, ion source temperature measurement, beam line component temperature monitoring, and coolant flow signal transmission, etc. These optical signal transition provisions are now performing part of the indispensable functions for the proper operation of the NB- TS facility. Attained experience and expertise are expected to be well applied to the upcoming main neutral beam injection (NBI) system construction for the KSTAR project.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.915-920
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• 2001

A spent fuel problem has prevented the nuclear power from claiming to be a completely clean energy source. The nuclear transmutation technology to incinerate the long lived radioactive nuclides and produce energy during the incineration process is believed to be one or the best solutions. HYPER(Hybrid Power Extraction Reactor) is the accelerator driven transmutation system which is being developed by KAERI(Korea Atomic Energy Research Institute). Some major feature of HYPER have been developed and employed. On-power fueling concepts are employed to keep system power constant with minimum variation of accelerator power. A hollow cylinder-type metal fuel is designed for the on-line refueling concept. Lead-bismuth(Pb-Bi) is adopted as a coolant and Spallation target material. HYPER is a subcritical reactor which needs an external neutron source. 1GeV proton beam is irradiated to Lead-bismuth(Pb-Bi) target inside HYPER, and spallation neutrons are produced. When proton beams are irradiated, much heat is also deposited in the Pb-Bi target and beam window which separates Pb-Bi and accelerator vacuum. Therfore, an effective cooling is needed for HYPER target. In this paper, we performed the thermal-hydraulic analysis of HYPER target using FLUENT code, and also calculated thermal and mechanical stress of the beam window using ANSYS code.