• Magazine of the Korea Concrete Institute
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• v.14 no.5
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• pp.15-20
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• 2002

갱폼이라 함은 주로 고층 아파트에서와 같이 평면상 상ㆍ하부 동일 단면 구조물에서 외부벽체 거푸집과 거푸집 설치ㆍ해체작업 및 미장ㆍ치장(견출) 작업발판용 케이지(cage)를 일체로 제작하여 사용하는 대형 거푸집을 말한다. 여기서 케이지는 갱폼에서 외부벽체 거푸집 부분을 제외한 부분으로 거푸집 설치ㆍ해체작업, 후속 미장, 치장(견출) 등 작업을 안전하게 수행하는데 필요한 작업발판, 안전난간 등으로 구성되어 갱폼 거푸집에 결합된 부분이며, 상부 케이지는 갱품 케이지의 4단 작업발판 중 거푸집 설치ㆍ해체작업용으로 사용되는 상부 2단 작업발판 구성 부분이고, 하부 케이지는 미장ㆍ치장(견출) 작업용으로 사용되는 하부 2단 작업발판 구성 부분을 말한다.(중략)

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1039-1046
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• 2007

In this paper, a coupled-defected ground structure(C-DGS) using negative inductive coupling is proposed and a bandstop filter(BSF) using C-DGS is designed and fabricated. The proposed C-DGS is the closely-located DGS cells for the negative coupling, the negative coupling of ground currents between adjacent DGS cells greatly improves the stopband characteristics. The proposed BSF utilizing the sharp cutoff response of the C-DGS has a -10 dB rejection band from 4 GHz to 11.3 GHz. A maximum attenuation rate is -64.3 dB/GHz in 3 cell structure, -108 dB/GHz in 5 cell structure. The C-DGS BSF shows the improved attenuation rate 3.8 times in 3 cell structure, 2.4 times in 5 cell structure, Also, the C-DGS BSF is reduced to 35.2 % and 40 % of the DGS BSF, respectively, due to the closely-located DGS cells. We fabricated the single gate mixer using C-DGS BSF. The single gate mixer has 6.6 dB conversion gain.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.374-382
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• 2017

This paper proposed a 2 stages 2-arm sinuous antenna that operates in frequency range 0.8-6GHz. The proposed antenna's total radius is 60mm, in which 1st stage's radius is 50mm which is designed as self-complementary structure(cell's angle width $90^{\circ}$) with 8 cell, and 2nd stage is composed of non-self-complementary structure with 0.5 cell of cell's angle width $720^{\circ}$ in the radius width 10mm. Measurement's result shows that -10dB return loss starts at 0.807GHz, but 1 stage 2-arm sinuous antenna that use the same radius starts at about 0.878GHz, so proposed the possibility of the miniaturization of the sinuous antenna.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.228-229
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• 2003

광자 크리스탈의 밴드 구조가 다른 물질이 접하는 경계면으로 구성되는 이종 접합 구조(Heteorostructure)는 단일 구조에서 관찰할 수 없는 특성을 보유하고 있으므로 관심을 끌고 있다. 이를 이용한 다 파장 add-drop 필터, 2D-3D 하이브리드 구조에 의한 무 회절 손실 도파로, beam splitter와 combiner 등의 연구 결과가 최근에 제시되었다. 본 논문에서는 positive 굴절율과 negative 굴절율을 갖는 광자 크리스탈이 이종 접합 구조를 형성할 때의 굴절 작용의 변화를 실린더의 반지름 변화에 따라 고찰하였다. (중략)

• Journal of Forest and Environmental Science
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• v.13 no.1
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• pp.114-133
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• 1997

Perforation plate was observed in 78 species(45 genera, 25 families) of Korean native hardwoods using SEM and it was divided into three types, i.e., simple, scalariform and multiple perforation plates, Based on occurance of these types, the species examined were classfied into the following six groups : (1) 60species(35 genera, 21 families) having exclusively simple perforation, (2) 5 species(2 genera, 1 families) having exclusively scalariform perforation plates, (3) 4 species(4 genera, 3 families) having simple and scalariform perforation plates, (4) 2 species(2 genera, 1 families) having simple and multiple perforation plates, (5) 5 species(3 genera, 3 families) having scalariform and multiple perforation plates and (6) 2 species(2 genera, 2 families) having simple, scalariform and multiple perforation plates. Mismatching perforation plates were found in two species of Betulaceae, Alnus hirsuta var. sibirica and Alnus hirsuta and peculiar substructure between the bars of the scalariform perforation plate was observed in Betulaceae, Betula davurica and Cercidiphyllaceae, Cerdiphyllum japonicum and the vestured perforation plate was found in Quercus aliena.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.11
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• pp.1666-1671
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• 2022

The structure of a high-power gain-flattened long wavelength band (L-band) optical amplifier was optimized, which was implemented for 64-channel wavelength division multiplexed optical signals with a channel spacing of 50 GHz. The output characteristics of this L-band amplifier were measured and analyzed. The amplifier of the optimized two-stage amplification configuration had a flattened gain of 20 dB within 1 dB deviation between 1570 and 1600 nm for -2 dBm input power condition. The noise figure under this condition was minimized to within 6 dB in the amplification bandwidth. The gain flattening was realized by considering only the characteristics of gain medium in the amplifier without using additional optical or electrical devices. The proposed amplifier consisted of two stages of amplification stages, each of which was based on the erbium-doped fiber amplifier (EDFA) structure. The erbium-doped fiber length and pumping structures in each stage of the amplifier were optimized through experiments.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.174-175
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• 2016

3-레벨 인버터의 경우 중성점을 기준으로 직류단 커패시터를 2개로 나누어 사용하기 때문에 부하의 불평형으로 인한 커패시터 간의 전압 불평형이 생길 수 있다. 이는 출력전류의 왜곡을 야기시키며 시스템 신뢰성에 악영향을 미친다. 본 논문은 직류단 커패시터의 전압 평형을 위한 3가지 밸런싱 회로구조를 조사하고 비교한다. 또한 PSIM 시뮬레이션을 통해 부하조건에 따른 밸런싱 회로의 성능을 확인한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.485-492
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• 2013

The effect on collection efficiency with 2-stage vortex finder diameter and back mixing of solid flow due to swirling intensity, turbulence eddies, wall bouncing using the residence time distribution of particle flow in a common and modified cyclone. Higher collection efficiencies of fly ash in a modified cyclone(S = 13, 15cm) are showed than common cyclone. Collection efficiency in modified cyclone was highest at 2-stage vortex finder diameter, S = 13 cm. Variances of residence time distribution and average residence times of glass bead were increased with a diameter(S) of 2-stage vortex finder due to swirling intensity and turbulence eddies. Back mixing of solid flow in a modified cyclone were increased with a gas inlet velocity and showed higher than a common cyclone.

• 전기의세계
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• v.32 no.7
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• pp.388-394
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• 1983

초전도 교류발전기에는 여러 종류의 구조가 있는데 본 해설에서는 현재 가장 많이 개발되고 있는 2중 차폐형 단일 회전자 발전기에 대하여 중점적으로 취급한다. 먼저 그 구조를 설명하고 초전도 교류발전기의 특징을 다루며 현재 개발현황을 소개한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8C
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• pp.806-815
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• 2006

It is studied to design a low pass filter of the SRC(sample rate converter), which is used to change the sampling rate of digital signals such as in digital modulation and demodulation systems. The larger the conversion ratio of the sample rate becomes, the more signal processing is needed for the filter, which corresponds to the more complexity in circuit realization. Thus it is important to reduce the amount of signal processing for the case of high conversion ratio. In this paper it is presented a design method of a two-stage cascaded FIR filter, which proved to have reduced amount of signal processing in comparison with a conventional single-stage one. The reduction effect of signal processing turned out to be more noticeable for larger value of conversion ratio, for instance, giving down to 72% in complexity for the conversion ratio of 32. It has been shown that the reduction effect is dependent to specific combination of conversion ratios of the cascaded filters. So an exhaustive search has been performed in order to obtain the optimal combination for various values of the total conversion ratio. In this paper every filter is considered to be implemented in the form of a polyphase FIR filter, and its coefficients are determined by use of the Parks-McCllelan algorithm.