• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 추계 학술대회논문집
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• pp.106-113
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• 2003

Smart UAV Development Program, one of the 21c Frontier R&D Program sponsored by MOST(Ministry of Science and Technology), was launched in 2002. As an air vehicle for the Smart UAV, CRW(Canard Rotor/Wing) concept was one of the candidates compared in trade-off study. The CRW concept has not only been proven completely but its aerodynamic characteristics not known in detail yet. Two calculation methods were adopted in this study to obtain aerodynamic data for the CRW. First method was the superpose DATCOM method which is capable of three lifting surfaces, and second one is the full Navier-Stokes computation around CRW configuration using overset grid method. Basic aerodynamic characteristics of the CRW configuration was analyzed and the minimum drag level with lift to drag ratio is presented. The peculiar flow characteristics around rotor/wing and hub were also examined and considered in the configuration design.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1310-1315
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• 2004

The present study deals with the unique characteristics of hydrogen jet diffusion flames, such as split flames and reignition phenomenon. The split flames are composed of a small flamelet on the nozzle rim and a lifted main flame at downstream. When mass flow rates of fuel reach a critical point, a small-sized flamelet is found to remain in the vicinity of the nozzle exit and the flame reignition subsequent to blowout of main flame occurs repeatedly. In this study, the non-luminous hydrogen jet diffusion flames are visualized by using schlieren technique in order to analyze the combustion characteristics of hydrogen jet diffusion flames with focus on the flame reignition phenomenon.

• 대한전자공학회논문지
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• 제24권5호
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• pp.804-812
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• 1987

1\ulcorner gate MESFETs are fabricated on MOCVD and VPE grown GaAs wafers using photolithography, chemical wet etching and lift-off techniques. DC characteristics such as Vt, Gm, Rs, etc. are studied and active channel parameters of MESFET(a, n, Leff, \ulcorner)are analyzed for 1-4 \ulcorner gate FETs and 100\ulcorner FAT FET. The correlation between DC data and active channel parameters are experimentally analyzed. The measured transconductance and low-field mobility in the active channel for the 1\ulcorner gate MESFET made on MOCVD wafer are 67mS/mm and 2980cm\ulcornerVs respectively.

• Journal of Magnetics
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• 제14권1호
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• pp.15-17
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• 2009

The magnetostatic interaction between the two magnetic nanowires was studied by using the longitudinal magneto-optical Kerr effect (MOKE). For this purpose two magnetic nanowires having different widths (400 nm, 800 nm) were fabricated on an Si substrate with electron beam lithography and the lift-off method. Magnetic hysteresis loops measured by MOKE showed double switching behavior, corresponding to the separated switching fields of each wire. The switching field of the narrow wire was greatly affected by the separation between the two wires. Based on how the switching field changes with decreasing separation, it is concluded that the magnetostatic field of the 800-nm wire strongly affects the switching of the 400-nm wire when the separation is less than $0.5{\mu}m$.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.50.2-50.2
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• 2009

사파이어는 질화물계 광전자소자 제작 시 박막 성장 기판으로 주로 사용되어 최근 그 중요성이 부각되고 있다. 특히 미세 패턴이 형성된 사파이어 기판을 이용하여 질화물계 발광다이오드 소자를 제작하면 빛의 난반사가 증가하여 광추출효율에 큰 개선이 나타난다. 또한 사파이어는 화학적 안정성이 뛰어나고, 높은 강도를 지녀 나노임프린트 등 여러 가지 패터닝 공정에서 패턴 형성 몰드로도 응용될 수 있다. 그러나 이와 같은 사파이어의 화학적 안정성으로 인하여 sub-micron 크기의 미세 패턴을 형성하기 힘들며, 현재 사파이어의 패턴은 micron 크기로 제한되어 사용되고 있다. 본 연구에서는 나노임프린트 리소그라피(NIL)를 사용하여 사파이어 웨이퍼의 c-plane위에 sub-micron 크기의 hole 패턴 및 pillar 패턴을 형성하였다. 우선 Hole 패턴을 형성하기 위해 사파이어 기판 위에 금속 hard mask 패턴을 UV 임프린트 공정과 etch 공정을 통해 형성하였다. 그리고 이 금속 패턴을 mask로 사파이어를 ICP 식각을 하여 hole 패턴을 형성하였다. 또한 Pillar 패턴을 형성하기 위해 lift-off 공정을 이용하여 금속 마스크 패턴을 형성하였고 이를 ICP 식각을 통해 사파이어 기판 위에 pillar 패턴을 형성하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.43-44
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• 2008

실리콘 웨이퍼 위에 마이크로웨이브 플라즈마 화학증착법으로 나노결정질 다이아몬드 박막을 형성하고 그 위에 RF 마그네트론 스퍼터로 ZnO 박막을 적층한 후 SAW(Surface Acoustic Wave) 필터를 제작하여 평가하였다. 기판온도, 작업압력, Ar/$CH_4$ 비율을 변화시켜 최적공정 조건에서 30nm 수준의 결정립을 갖는 $4{\mu}m$ 두께의 다이아몬드 박막을 얻었고, RF 인가전력, 기판온도, Ar/$O_2$ 비율을 조정하여 결정성이 우수하고, 표면 거칠기가 좋으며, 높은 비저항을 갖는 $2.2{\mu}m$ 두께의 ZnO 박막을 얻었다. 박막의 특성은 FESEM과 XRD로 평가하였다. Lift-off 식각공정을 이용하여 일정한 선폭과 간격(Line/Space : 1.5/$1.5{\mu}m$)을 갖는 구리 전극 패턴을 형성하였다. Network Analyzer를 이용하여 측정한 SAW 필터의 중심주파수는 1.67GHz이었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.267-269
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• 1996

In this work, the influence of wire type conducting particles on the insulation reliability of GIS has been systematically investigated when outer electrode was dielectric coated by epoxy resin. For this purpose, coaxial cylinder-type electrode was adopted in 362 kV chamber and various size of Cu conducting particle was used and different gas pressure was applied. To prove the coating effect on the gas insulation, different thickness of epoxy coated outer electrode have been considered and the lift-off voltage and flashover voltage have been analyzed. The results show that the dielectric coated electrode has an remarkable influence on the reducing particle behavior in GIS system and enhancing the GIS insulation reliability.

• 한국연소학회지
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• 제6권1호
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• pp.29-35
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• 2001

The surface flames in porous ceramic burner are experimentally characterized to investigate the effects of equivalence ratio and firing rates. The results show that the surface flames are classified into green, red radiant and blue surface flame as decrease of equivalence ratio. And each flame is maintained very stably and shows the same flame characteristics at any orientation of ceramic burner. Particularly the blue surface flame was found to be very stable at very lean equivalence ratio at 200 to $800\;kw/m^2$ firing rates. And the exhausted NOx was analysed to find out which flame has lower NOx emission. The blue surface flame showed the lowest NOx emission regardless of the location of burner since it sustained very stable at lean mixture ratio.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.566-569
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• 2008

와전류탐상(ECT) Transmit-Receive 프로브를 이용한 ECT 방법은 센서코일의 유도기전력의 변화를 관찰하여 피검사체의 결함이나 특성의 변화를 탐지해내는 방법이다. ECT T/R 프로브는 여러 개의 Pancake 코일로 구성되어있고, 각각의 코일은 Transmit 코일과 Receive 코일로 나뉜다. 본 논문은 실제 TH 프로브 제작에 앞서 동일한 특성을 갖는 와전류센서를 설계 및 제작하여 그 특성을 파악하였다. 와전류센서에 인가되는 시험주파수와 Lift-off의 변화에 대한 특성을 파악하고 와전류센서의 임피던스값을 산출하여 정규화 임피던스도를 그려 와전류센서의 특성을 살펴보았다.

• 한국항해항만학회지
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• 제35권2호
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• pp.167-172
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• 2011

The motivation of this study is the recent advancement of the Straddle Carrier (S/C). Previously Straddle Carrier (S/C) system was used focusing on container lift on/off due to its lower driving speed than that of (Y/T). Shuttle Carrier is evaluated as an upgraded Straddle Carrier. Recently, however, the driving speed of (S/C) has been improved to the level of Yard Tractor and Trailer systems (Y/T), which is 30Km per hour which makes (S/C) qualified as terminal in-yard transportation equipment. This paper, therefore, aims to evaluate three types of terminal in-yard transportation equipments such as (Y/T), (AGV) and the advanced (S/C) from economic perspective. The results revealed that by observing the total costs of equipment, (S/C) is a cheaper option than (Y/T) over 20 years, and than (AGV) over 6 years.