• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.3-5
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• 2004

Balanced input 단을 갖는 IC chip과의 interface를 위하여 2.4GHz 대역의 Balun BPF를 설계하였다. $2.4{\times}2.0 (mm)$ 크기의 LTCC chip 형태로 제작하기위하여 LPF-HPF 형태를 응용한 집중소자형 Balun을 설계하고 Comb-line 형태의 BPF를 접합하여 설계 및 시뮬레이션을 하였다. 시뮬레이션 결과 Balun BPF의 삽입손실은 3.03dB, 위상차는 $170^{\circ}$, Amplitude balance는 0.09dB이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.164-167
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• 2002

SiC direct bonding technology is very attractive for both SiCOI(SiC-on-insulator) electric devices and SiC-MEMS applications because of its application possibility in harsh environments. This paper presents on pre-bonding according to HF pre-treatment conditions in SiC wafer direct bonding using PECVD oxide. The characteristics of bonded sample were measured under different bonding conditions of HF concentration, and applied pressure. The 3C-SiC epitaxial films grown on Si(100) were characterized by AFM and XPS, respectively. The bonding strength was evaluated by tensile strength method. Components existed in the interlayer were analyzed by using FT-IR. The bond strength depends on the HF pre-treatment condition before pre-bonding (Min : 5.3 kgf/$\textrm{cm}^2$∼Max : 15.5 kgf/$\textrm{cm}^2$).

• Journal of Welding and Joining
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• v.19 no.6
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• pp.643-651
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• 2001

A new waveform control technique has been developed for suppressing the spatter generation in the repelled transfer mode of high current $CO_2$ welding. Based on the spatters in repelled transfer, a waveform concept of concept was established in a way to drop the welding current to lower level right before the pendant weld drop detatchment so that the explosion force associating with drop detatchment was decreased. There were several variables to be controlled such as the moment of current drop, the base current and the time of retention at the base current. Either at lower base current or at longer retention time, the more instantaneous shot circuits were int개duced and thus the spatter generation rates were increased. With optimizing the control variables, the amount of spatter generated was decreased by about 30%.

• Progress in Superconductivity
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• v.13 no.1
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• pp.47-51
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• 2011

Mono-atomic-layer graphene is an interesting system for studying the relativistic carrier transport arising from a linear energy-momentum dispersion relation. An easy control of the carrier density in graphene by applying an external gate field makes the system even more useful. In this study, we measured the Josephson current in a device consisting of mono-layer graphene sheet sandwiched between two closely spaced (~300 nm) aluminum superconducting electrodes. Gate dependence of the supercurrent in graphene Josephson junction follows the gate dependence of the normal-state conductance. The gate-tunable and relatively large supercurrent in a graphene Josephson junction would facilitate our understanding on the weak-link behavior in a superconducting-normal metal-superconducting (SNS) type Josephson junction.

• Journal of Welding and Joining
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• v.12 no.3
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• pp.18-25
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• 1994

최근 건축용 강구조물이 초대형화 및 초고층화됨에 따라 용접물량의 급증하고 있으나 3D 직종에 대한 회피현상으로 용접기능자의 감소 및 인건비의 급증 등으로 인하여 건축용 강 구조물 제작시 경쟁력이 갈수록 저하되고 있다. 이에 대한 자구책으로 강 구조물 제작업체에서는 생산 성을 한층 배가 시킬 수 잇는 용접시공 기술을 자체 개발하거나 외부로부터 도입하고 있다. 본 보에서는 당사를 비롯하여 여러 업체에서 최근 개발된 용접기술 특히 대전류 SAW 기법, SESNET 기법 등의 초대입열 용접기술, Metal cored wire나 TIME 기법에 의한 고능률 GMAW 기법 및 Robot 용접 등에 대하여 간략히 기술하였다. 이 용접기술들의 적용에는 대개 고가의 시설투자가 수반되나, 이는 생산성 증가에 따른 원가절감으로 충분히 상쇄될 수 있다. 그러나 상기된 용접기술들의 적용에 대한 성패는 용접장비의 특성, 용접조건의 확립, 모재의 특성 혹은 주변 자동화 기술 및 상호 종속적인 관계에 크게 의존된다. 따라서 가 강 구조물 제작업체에서는 세심한 주위환경 분석을 토대로 각 업체에 가장 합당한 용접기술을 선정 및 적용하여야 하겠다.

• Journal of Welding and Joining
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• v.31 no.1
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• pp.21-25
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• 2013

Aluminum alloy, Al5083-O, is one of candidate materials for the LNG storage tank, because of its excellent weldability, cryogenic characteristics, and corrosion resistance. The good weldability of Al5083-O is very important in LNG storage tank manufacturing. In this study, high current metal inert gas(MIG) welding process was used to get one pass welding of thick plate aluminum alloy. Bead on plate(BOP) welding was performed to evaluate the effect of welding conditions on the height of bead and depth of penetration. The optimum welding conditions were derived to get one pass welding of the thickness of 14.5mm. The mechanical properties of the welded joint were evaluated. The cross-sectional macro test, tensile test, and bending test satisfied the class rule.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2456-2458
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• 1999

The polarization mode dispersion (PMD) that restricts the transmission bandwidth was investigated in standard long single mode fiber which optimized at 1.3${\mu}m$. Although fiber has perfect circular symmetry, each optical fiber has different refractive index profiles. The investigation of PMD with random mode couplings were conducted in three kinds of fiber by the time-domain interferometric method. By using two manufacturing methods, MCVD(Modified Chemical Vapor Deposition) method and VAD(Vapor Phase Axial Deposition) method, the property of mechanical asymmetric lateral pressure, bending and twisting induced polarization mode dispersion were measured. The concatenated optical fibers were compared with other types.

• The Korean Journal of Malacology
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• v.11 no.2
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• pp.171-179
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• 1995

한국산 다슬기류의 종별 유전적 변이를 알아보고 계통분류학적 근거를 제공하기 위하여 다슬기속(Simisulcospira)에 속하는 다슬기(S. libertina),주름다슬기,(S. forticosta), 곳체다슬기(S. gottschei), 좀주름다슬기(S. tegulata)및 참다슬기(S. coreana)등 5종을 전국 각지에서 채집하여 전기영동(starch gelelectrophoresis)를 이용해 분자유전학적 분석을 실시한 결과를 용약하면 아래와 같다. 유전적 다형형의 빈도는 58%에서 83%로 대단히 높았고 이형접합자의 평균 빈도도 50%내외였다. Rogers' D를 근거로 한 각 종간 유연관계는 주름다슬기와 곳체다슬기가 근연관계를 이루고 있었으며 이들 두 군과 다슬기는 유전적으로 거리를 두고 있었다. 이러한 결과는 패각의 형채와 비교할 때 유사한 경향을 보였다.

• Journal of Welding and Joining
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• v.12 no.1
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• pp.94-101
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• 1994

In this study, plasma spraying has been used to produce $TiO_2$ polycrystalline coatings from $TiO_2$ powders. The physical and chemical properties of plasma sprayed $TiO_2$ coatings depend greatly on plasma spraying conditions. The electrical resistivity, oxygen concentration, photocurrent and crystal structure of plasma sprayed $TiO_2$ coating has been studied. The results are as follows: 1. The oxygen loss and electrical conductivity of $TiO_2$ plasma sprayed coatings increased by low pressure and high amount of auxiliary gas, hydrogen in plasma spraying. 2. Oxygen loss increase electrical conductivity, and decrease photocurrent of $TiO_2$ plasma sprayed coatings. 3. Photocurrent of $TiO_2$ plasma sprayed coatings manufactured in atmospheric pressure is higher than that of low pressure.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.142-143
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• 2002

최근 RSFQ (Rapid Single Flux Quantum) 기술은 초고속, 극저전력의 초전도 디지털 전자회로의 구현 가능성으로 인해 많은 관심을 모으고 있다.[1] 특히 정밀측정 및 표준 분야에 있어서, 기존의 직류 전압표준 소자에 비해 작동이 간편하며, 다양한 측정기술에 활용할 수 있는 차세대 조셉슨 전압표준용 소자에 응용가능성이 주목받고 있다. 그러나 RSFQ의 이러한 강점들이 제대로 발휘되려면 1 ㎄/$\textrm{cm}^2$ 수준의 고임계전류, 10 $\mu\textrm{m}$ 이하의 미소 조셉슨 접합을 신뢰성 있고 재현성 있게 제작할 수 있어야한다. (중략)