• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1944_1945
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• 2009

In this research, the bidirectional-communication-media-system which is not able to implement by using the existing coaxial cable was manufactured and the method applicable to Educational Environment was proposed. Also, it is implemented that we can use various media contents through narrow bandwidth by network-linking. The unified broadcasting system applicable to Educational Environment based on IPTV was implemented in the last.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.36-40
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• 2013

Recently, electronic equipments become smaller, more functional, and more complex than before. As these trends, MLC(multi-layer ceramic) circuit has been emerged to a promising technology in semiconductor inspection industry. Especially, multi-layer ceramic which is consisted of many fine-pitch multi-hole is used to produce a semiconductor inspection unit. The hole is processed by UV laser. But, working conditions are changed all the time. Therefore real time measurement of fine-pitch multi-hole is very important method for ensuring performance. In this paper we found the best method for illuminating and auto focusing. And, we verified our equipment.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.7-12
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• 2003

각광을 받고 있는 광통신 분야의 핵심부품인 페룰은 일본이 전 세계의 95%를 장악하고 있다. 국내에서도 일부 업체에서 양산을 하고 있으나, 핵심 연삭공정에 사용되는 연삭 가공장비는 전량 수입되고 있는 실정이다. 페룰은 0.1∼0.3$\mu\textrm{m}$의 동심도, ${\pm}$ 0.2$\mu\textrm{m}$의 외경치수, 0.1$\mu\textrm{m}$대의 진원도와 원통도, 10nm의 표면 거칠기를 구현해야 세계적 경쟁력을 갖출 수 있는 초미세, 초정밀 기계가공 부품이다.(중략)

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.227-230
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• 2010

본 논문은 디지털 케이불망에서 초고선명 TV(Ultra High Definition TV) 서비스를 위한 100Mbps급 1024-QAM 전송시스템 개발에 관하여 기술한다. 8K-UHD TV(해상도 7680x4320) 콘텐츠 전송을 위해서는 l개의 프로그램당 약 100-160Mbps의 대용량 데이터 전송률이 확보되어야 하며. 이러한 대용량 데이터 전송을 위해 타매체에 비해 상대적으로 전송채널 환경이 우수한 디지털 케이블망(HFC:Hybrid Fiber and Coaxial)을 이용한 대용량 실감데이터 전송기술에 대한 연구가 주목받고 있다. 본 논문에서는 이와 같은 UHD 실감콘텐즈 전송을 위하여, OpenCable(J.83 Annex B) 확장형 1024-QAM 송수신기술 및 방송망 채널본딩기법을 적용한 100Mbps급 송수신 기술개발에 대한 내용을 기술한다.

• Journal of the Korean Society of Visualization
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• v.3 no.2
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• pp.3-13
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• 2005

The optical patterantor provides the high resolution and quantitative information of the spray. Fuel distribution and Sauter Mean Diameter (SMD) can be measured from fluorescence and Mie-scat-tering images. To correct the attenuation of the laser beam and signal in dense spray region, the method to find the geometric mean of the signal intensities obtained from two cameras was evaluated and verified in a solid-cone spray. In high pressure environment, the increased number density of the droplets cause multiple scattering. The optical patternation technique using a laser beam instead of a laser sheet was applied to minimize the multiple scattering problem. The pattern of a coaxial spray was changed from hollow-cone to solid-cone shape, and the spray angle was reduced as the ambient pressure increased from 0.1 to 4.0 MPa.

• Journal of the Korean Vacuum Society
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• v.3 no.1
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• pp.8-16
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• 1994

표면분석용CAICISS장치를 제작하고 He+과 Li+이온을 사용하여 장치의 특성을 조사하였다. 장치 분해능의 평가기준으로 이용할 수 있는 ΔT를 정의하고 Li+ 이온을 사용했을 경우와 비교한 결과 He+ 이온의 경우 ΔT/T=0.034, Li+ 이온의 경우 ΔT/T=0.04로서 Li+이온의 경우가 분해능이 약간 떨어짐을 알았다. 그리고 Ta, Al 표적시료에 대한 실험결과를 보정함수를 이용하여 계산값과 비교한 결과 잘 일 치함을 확인하였고 보정함수는 입사이온의 에너지와 표적원자의 질량에는 무관하고 실험조건에만 의존 함을 알았다. 또한 Si(100) 표면에 He+ 이온을 입사하여 입사각에 따른 산란강도 분포 스펙트럼으로부터 CAICISS 장치로 표면 1∼4 원자층의 Si 원자에 대한 기하학적인 배열을 확인하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1727-1732
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• 2011

In order to realize a high performance(low loss, high isolation) microwave power divider/combiner, we have designed the power combiner/divider precisely in accordance with the different hight of central part. In the case of the high central part of the hight of $h_r$=10.2, a compensating part of the conical line is inserted in the conical conversion transmission line, and in the case of low central part of the hight of $h_r$=5.0, the conical conversion transmission line is remodeled into the 2-stage bend structure. In both case, the reflection characteristics are improved to 30dB over the operating frequency range of 5GHz bandwidth. A resistance is inserted between the peripheral ports so as to try to improve the isolation characteristics of the device. For the 16-divider/combiner, the isolation characteristics are improved to 10dB over the operating frequency range of 5GHz bandwidth.

• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.80-85
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• 2004

Electromagnetic interference(EMI) shielding characteristics of composite filled with Cu flake and carbon brush powder as hybrid conductive filler and EAF slag have been studied. The coaxial transmission line method of ASTM D4935-99 was used to measure the EMI Shielding effectiveness of composites as formulation in frequency rage $100\~1,000MHz$ The SE also increases with the increase in flier loading. The hybrid filler filled composites show higher SE compared to that of only Cu flake. The correlation between SE and conductivity of the various composites is also discussed. The results indicate that the composites having higher filler loading$({\geq}40wt.\%)$ can be used for the purpose of safety materials to protect hazardous electromagnetic interference.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.147-155
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• 2001

The NOx emission characteristics of jet flames fueled with $H_2$ and $CH_4$ were studied. Experimental and numerical investigations were carried out for various flames with varying equivalence ratio, fuel flow rate and nozzle diameter. The Emission indices of NOx(EINOx) were measured by chemiluminescent method and calculated by simulation using detailed chemistry. The results show that EINOx of $CH_4$ and $H_2$ flames have different trends in terms of equivalence ratio and fuel flow rate but have the same trends in terms of nozzle diameter. These differences can be explained by the following Thermal and Prompt trends in both flames. Thermal EINOx trends can be describe in function of residence time in the high-temperature region weighted by the maximum flame temperature and Prompt EINOx trends can be described in function of flame surface area of each combustion conditions.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.305-313
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• 2005

Measurements of flame length, width and NOx emissions have been conducted to investigate the effect of an acoustic excitation on flame structure in turbulent hydrogen diffusion flames with coaxial air. The resonance frequency of oscillations was varied between 259 ,514 and 728 Hz with power rate of 0.405 and 2.88w. When these frequencies imposed to hydrogen flames, dramatic reduction of flame length and NOx emission was achieved. And acetone planar laser-induced fluorescence technique was used to measure a concentration of the near field of driven axisymmetric jet. The air-fuel stoichiometric line was plotted to investigate the mixing layer and development of air entrainment to fuel jet. Consequently, acoustic excitation on flame could enhance the air-fuel mixing resulting in abatement of NOx emission quantitatively.