• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.102-111
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• 1989

In this paper two new non-inverting type BiCMOS drivers are proposed. These are characterized by the use of pMOSFET's in charging the bases of pull-down bipolar transistors. The delay time in pull-up transition of the proposed drivers is 20%-47% shorter than that of the drivers of current using. The proposed drivers use 1-3 fewer MOSFET's in comparison with the drivers of current using.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.161-168
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• 2004

우리가 살아가는 3차원 이상의 지형공간을 영상으로 구형하기 위하여 필수적으로 요구되는 DEM을 비교적 손쉽게 확보할 수 있는 SPOT 영상을 이용하여 자동으로 생성할 수 있는 방법을 제시하고 에피폴라 투영법에 의한 결과영상의 평가를 통하여 몇 가지 좋은 방법을 제안하고자 한다 현재 보유하고 우리나라 춘천시의 SPOT 위성 팬크로 영상과 수치지도의 DEM영상과의 생성결과를 비교 평가하였다. SPOT2-3호(10m)에서 수집한 중복영상에서 자동으로 수치표고모델을 작성함으로서 다양한 영상정보의 활용이 가능해 따라 입체영상지도제작 및 분석이 가능해지고 있다. 본 연구에서는 SPOT 60km의 춘천지역을 대상으로 한눈에 영상과 영상을 재현할 수 있도록 고해상도의 인공위성 영상자료를 처리하여 영상지도를 제작하기 위한 수치표고모형을 자동으로 추출할 수 있도록 하였다.

• Information and Communications Magazine
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• v.17 no.12
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• pp.59-66
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• 2000

소자의 특성을 정확히 묘사하고 이를 회로설계에 사용하기 위해서는 정확한 모델링과 이에 관련된 모델변수를 정확히 추출하는 것이 중요하다. 특히, 바이폴라 접합 트랜지스터 및 SiGe HBT를 비롯한 이종접합 트랜지스터의 베이스 저항은 베이스 단자로부터 전류가 에미터-베이스의 접합면을 향해 퍼져 들어가기 때문에 이 전류가 겪는 저항 성분(spreading resistance)은 하나의 고정값으로 구할 수가 없으며 전류값에 따라 그 효과가 민감하게 변하게 된다. 이와 같은 이유로 다른 어떠한 모델변수들 보다 베이스 저항 모델변수의 정확한 추출이 매우 어렵다. 본 논문에서는 DC에서 측정된 베이스 저항값을 기본으로 하여 베이스 저항 모델변수들을 정확하고 체계적으로 추출하는 방법에 관하여 논의한다. 본 논문의 베이스 저항 관련 모델변수들의 추출에는 한국전자통신연구원에서 개발한 SiGe HBT 소자를 사용하였으며, 또한 모델 변수 추출은 SILVACO사의 UTMOST III 컴퓨터 프로그램을 이용하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.158-158
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• 2009

TiN 코팅은 뛰어난 기계적 성질 및 내식성으로 산업전반에 걸쳐 널리 이용되고 있다. 본 연구에서는 비대칭 바이폴라 펄스 DC 반응성 마그네트론 장비를 이용하여 바이어스전압, 펄스주파수 및 Duty를 변화시키면서 TiN 박막을 제작하였다. 위와 같은 3가지 플라즈마 변수의 변화에 따른 TiN 박막의 결정 배향성 및 미세구조에 미치는 영향에 대해 주목하였다.

• Journal of Surface Science and Engineering
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• v.47 no.4
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• pp.168-173
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• 2014

The paper presents the comparative results of TiAlN coatings deposited by DC and pulsed DC asymmetric bipolar magnetron sputtering systems. The results show that, with the decreasing duty cycle and increasing pulse frequency, the coating morphology changes from a columnar to a dense structure, with finer grains. Pulsed sputtered TiAlN coatings showed higher hardness, higher residual stress, and smaller grain sizes than dc prepared TiAlN coatings. Moreover residual stress of pulsed sputtered TiAlN coatings increased on increasing pulse frequency. Meanwhile, the surface roughness decreased continuously with increasing pulsed DC frequency up to 50 kHz.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.103.2-103.2
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• 2017

Nanocrystalline HfN coatings were prepared by reactively sputtering Hf metal target with N2 gas using a magnetron sputtering system operated in DC and ABPP (asymmetric bipolar pulsed plasma) condition with various duties and frequencies. The effects of duty and frequency, ranging from 75 to 100 % and 5 to 50 kHz, on the coating microstructure, crystallographic and mechanical properties were systematically investigated with FE-SEM, AFM, XRD and nanoindentation. The results show that pulsed plasma has a significant influence on coating microstructure and mechanical properties of HfN coatings. Coating microstructure evolves from the columnar structure to a highly dense one as duty decreases. Average grain size and nano hardness of HfN coatings were also investigated with various pulsed conditions.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.6
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• pp.13-19
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• 2004

This study was performed to evaluate permeable properties of eco-concrete using soil, natural coarse aggregate, soil compound and polypropylene fiber. The fIexural strength, ultrasonic pulse velocity and dynamic modulus of elasticity were increased with increasing the content of coarse aggregate, soil compound and polypropylene fiber. The flexural strength, ultrasonic pulse velocity and dynamic modulus of elasticity were 259 MPa, 3,527 m/s and 275 ${\times}$ 102 MPa at the curing age of 28 days, respectively. The coefficient of permeability was decreased with increasing the content of coarse aggregate and soil compound, but it was increased with increasing the content of polypropylene fiber. Accordingly, this concrete can be used for farm road.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.179-184
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• 2004

High-resolution satellite imagery are used in various application field such as generation of DEM, orthophto, and three dimensional city model. To define the relation between image and object space, sensor modelling and generation of the epipolar image is essential processes. As the header information or physical sensor model becomes unavailable for the end users due to the national security or commercial purpose, generation of epipolar images without these information becomes one of important processes. In this study, epipolar geometry is generated and analysed by applying two generalized sensor models; parallel and parallel-perspective model Epipolar equation of the parallel model has linear property which is relatively simple; Epipolar geometry of the parallel-perspective model is non-linear. This linear property enable us to generate epipolar image efficiently.

• Journal of Surface Science and Engineering
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• v.48 no.4
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• pp.136-141
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• 2015

The paper presents the comparative results of NbN coatings deposited by DC and pulsed DC asymmetric bipolar magnetron sputtering systems. The results show that, with the decreasing duty cycle and increasing pulse frequency, the coating morphology changes from a columnar to a dense structure, with finer grains. The Pulsed sputtered NbN coatings showed higher hardness, higher residual stress, and smaller grain sizes than those of DC prepared NbN coatings. Moreover residual stress of pulsed sputtered NbN coatings increased on increasing pulse frequency. Meanwhile, the surface roughness decreased continuously with increasing pulsed DC frequency up to 50 kHz.

• Journal of Surface Science and Engineering
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• v.49 no.5
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• pp.461-466
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• 2016

Nanocrystalline vanadium nitride (VN) coatings were deposited using asymmetric bipolar pulsed dc sputtering to further understand the influence of the pulsed plasmas on the crystal structure, microstructure and mechanical properties. Properties of VN coatings were investigated with FE-SEM, XRD and nanoindentation. The results show that, with the increasing pulse frequency and decreasing duty cycle, the coating morphology changed from a porous columnar to a dense structure, with finer grains. Asymmetric bipolar pulsed dc sputtered VN coatings showed higher hardness, elastic modulus and residual compressive stress than dc sputtered VN coatings. The results suggest that asymmetric bipolar pulsed dc sputtering technique is very beneficial for the reactive sputtering deposition of VN coatings.