• E2M - 전기 전자와 첨단 소재
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• 제10권9호
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• pp.922-929
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• 1997

As the size of semiconductor devices shrinks in the horizontal as well as vertical dimension it is difficult to estimate the transport-velocity of electron because they drift in non-equilibrium with a few scattering. In this paper HYbrid Monte Carlo simulator which employs the drift-diffusion model for hole-transport and Monte Carlo model for electron-transport in order to reduce the simulation time and increase the accuracy as well has been developed and applied to analyze the electron-transport in InAlAs/InGaAs HBT which is attractive for an ultra high speed active device in high speed optical fiber transmission systems in terms of the velocity and energy distribution as well as cutoff frequency.

• 디지털콘텐츠학회 논문지
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• 제5권3호
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• pp.171-175
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• 2004

본 논문에서는 TH PPM UWB-IR 시스템에서 다중 접속시 발생하는 간섭을 개선하기 위해 CCI canceller를 적용하여 동일 채널 상의 다중 사용자 간섭을 제거하였다. 결과에 의하면, CCI canceller를 적용함으로써 낮은 수신 전력에서도 고속의 데이터 전송이 가능한 수신 성능을 얻을 수 있었고 100Mbps의 고속 전송 시에도 최대 동시 접속 수 40까지 수용이 가능한 채널 용량을 얻을 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.361-364
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• 2003

The customer premise facilities assume an important role in the telecommunication networks. The present technical standards for domestic customer cabling facilities are established with the multimedia environment reflected, but are insufficient for accommodation of multimedia services of the ultra high-speed information and communication networks In the present paper, the status of international standardization as well as technical standards in the U.S.A., Japan, other countries are reviewed and the domestic technical standard and emblem is investigated and analyzed in order to enhance customer cabling facilities in Korea. The problems with emblem are analyzed, and how to improve customer cabling telecommunication facilities is suggested based on the above.

• 한국전자파학회논문지
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• 제25권12호
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• pp.1251-1257
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• 2014

본 논문에서는 6~13 GHz 주파수 범위에서 30 kHz 이하의 주파수 분해능과 500 ns 이하의 동조 속도를 갖는 광대역 고속 주파수 합성기 구조를 제안하였다. 광대역에서 빠른 동조 속도와 우수한 위상잡음 특성, 고해상도 주파수 특성을 얻기 위해 DDS(Direct Digital Synthesizer)와 아날로그 직접 주파수 합성기술을 적용하여 주파수 합성기의 출력을 합성하였다. 그리고 광대역 주파수 합성기의 위상잡음 특성을 중첩의 원리를 이용하여 예측하였고 측정 결과와 비교하였다. 제작된 주파수 합성기의 주파수 동조 속도는 500 ns 이하, 위상잡음은 최고 주파수에서 -106 dBc @ 10 kHz 이하, 주파수 정확도는 ${\pm}2kHz$ 이하로 측정 되었다.

• 조명전기설비학회논문지
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• 제24권2호
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• pp.27-32
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• 2010

본 논문은 반도체 공정에 사용되는 고속 EFEM(Equipment Front End Module) 장치의 새로운 성능평가시스템을 제안한다. 다관절 로봇으로 구성된 EFEM은 실리콘 웨이퍼 또는 포토마스크를 클린 스토리지 캐리어와 각종 계측 및 테스팅 시스템 사이를 이동시키는 반도체 자동화의 핵심장치이다. 성능평가 시스템 개발을 위한 이론과 실험적인 연구가 수행되었고, 그 결과는 고속 EFEM 장치의 성능 평가시스템이 적합함을 입증한다. 특히, WTO/TBT(Technical Barhers to Trade) 협정 및 PL(Product Liability)법에 대처하는데 매우 효과적이다.

• Journal of Welding and Joining
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• 제32권3호
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• pp.81-88
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• 2014

As the industrial technology has been developed, a dissimilar welding has been received huge attention in various engineering fields. To understand the mechanical properties and possibility of applications of dissimilar metals joining, the laser welding of Cu and Ni dissimilar metals was studied in this paper. Cu and Ni have differences in materials properties, and Cu and Ni make no intermetallic compounds according to typical binary phase of Cu and Ni system. In this study, lap welds of Cu and Ni dissimilar metals using single-mode fiber laser with high welding speed were tried, and mechanical properties of the welds zone were evaluated using a Vickers hardness test and a tensile shear test. To recognize the relation between hardness and tensile shear load, weld fusion zone of interface weld area were observed. And it was confirmed that the ultra-high welding speed could make good weld beads and higher hardness parts had higher tensile shear load under the all conditions.

• 한국철도학회논문집
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• 제18권4호
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• pp.317-324
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• 2015

초고속 자기부상철도는 전기, 전자, 기계, 토목 및 건설 등의 기술이 종합적으로 연계된 거대 복합 시스템이다. 따라서, 각 기술 간의 인터페이스와 시스템에 대한 운영 요구사항과 기본사양을 종합적으로 검토 및 관리하는 시스템 통합이 원활하게 진행되어야 한다. 개별적인 시스템의 인터페이스 성능 확보는 시스템 전체의 목표 달성을 위해 필수적인 사항으로써 시스템 엔지니어링의 주요 관리 항목이며, 시스템의 실패 요인을 사전에 방지할 수 있는 효과적인 방안이다. 본 연구에서는 시스템 엔지니어링 기법을 활용하여 초고속 자기부상철도 시스템의 안정성과 신뢰성을 향상시킨 연구에 대하여 서술하였다.

• Tribology and Lubricants
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• 제10권3호
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• pp.18-28
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• 1994

Sliding friction between a spherical pin of 8mm in diameter and flat (disk) substrates coated with vacuum-deposited thin film was measured under ultra high vacuum pressure for various materials, various rates of film supply (8~210 nm/min), various sliding velocities (1.5~67.0 mm/s). It was found that the most effective lubrication was obtained when the adhesion between $Si_3N_4$ pin and SUS440C disk was high and that between $Si_3N_4$ pin and $Si_3N_4$ disk was low. When In film was used as a lubricant between $Si_3N_4$ pin and stainless steel disk, the friction coefficient had a value as low as 0.04. In this case, the normal load W and the sliding speed V were expressed as 10N and 24 mm/s for $10^{-6}Pa$. The dependence of $\mu$ on the thickness h of the Ag film, which was used as a lubricant between $Si_3N_4$ pin and SUS440C (Q) disk was expressed as $\mu$=0.12 for W=10N and V=24mm/s when the film was thicker than 100nm. A brief discussion on these relations is presented from the viewpoint of the real contact area.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.131-134
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• 2011

Back-end-of-line using ultra low-k (ULK; k < 2.5) has been required to reduce resistive capacitance beyond 45 nmtechnologies, because micro-processing units need higher speed and density. There are two strategies to manufacture ULK inter-layer dielectric (ILD) materials using an air-gap (k = 1). The former ULK and calcinations of ILD degrade the mechanical strength and induce a high cost due to the complication of following process, such as chemical mechanical polishing and deposition of the barrier metal. In contrast, the air-gap based low-k ILD with a relatively higher density has been researched on the trench-type with activity, but it has limited application to high density devices due to its high air-gap into the next metal layer. The height of air-gap into the next metal layer was reduced by changing to the via-typed air-gap, up to about 50% compared to that of the trench-typed air-gap. The controllable ULK was easily fabricated using the via-typed air-gap. It is thought that the via-type air-gap made the better design margin like via-patterning in the area with the dense and narrow lines.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1279-1282
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• 2006

An ultra low-power down-conversion level shifter using low temperature poly-crystalline silicon thin film transistors is proposed for mobile applications. The simulation result shows that the power consumption of the proposed circuits is only 17% and the propagation delay is 48% of those of the conventional cross-coupled level shifter without additional area. And the measured power consumption is only 21% of that of the crosscoupled level shifter.