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자동차 인포테인먼트 네트워크를 위한 1394 오토모티브 분석 및 구현
한일석(IlSeok Han),김병수(ByoungSoo Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
This paper introduces a new 1394 automotive multimedia network for in-vehicle infotainment and telematics applications. These require a large amount of data to be transmitted on-board and also exchanged with the external world. Because of a large amount of data, conventional in-vehicle networks could not be used in infotainment systems which QoS(Quality Of Service) required. Ethernet, 1394 Automotive, and MOST are vying for a slice of the rapidly expanding these applications. In this paper, the 1394 automotive network was adopted in order to apply these domains. A new design method to transmit simultaneously multiple real-time audio and video are also introduced. We also present an analysis of different protocols and technologies used in in-vehicle multimedia networks.
GaAs/AlGaAs Quantum Cascade Laser에서 Deep Mesa 구조에 의한 문턱전류 감소
한일기,송진동,이정일,Han, Il-Ki,Song, Jin-Dong,Lee, Jung-Il 한국진공학회 2008 Applied Science and Convergence Technology Vol.17 No.6
GaAs/AlGaAs based quantum cascade lasers were fabricated with two different types of i) the shallow mesa type which was etched up to above active region and ii) the deep mesa type which was etched through active region. While the threshold current density of shallow mesa type was $26-32\;kA/cm^2$, the one of deep mesa type was reduced drastically up to $13\;kA/cm^2$. Such lowered threshold current density at deep mesa type attributed to the reduction of current loss to the lateral directions. GaAs/AlGaAs 물질계를 기반으로 한 양자폭포레이저를 제작하였다. 양자폭포레이저는 활성층의 위까지만 식각된 shallow mesa 구조와 활성층까지 식각된 deep mesa 구조로 제작되었다. shallow mesa 구조의 경우 문턱전류 밀도가 $26-32\;kA/cm^2$이었지만 deep mesa 구조의 경우 문턱전류 밀도는 $13\;kA/cm^2$로 대단히 감소되었다. Deep mesa 구조에서의 문턱전류 감소는 측면 방향으로의 전류 손실이 감소되었기 때문으로 설명되었다.
Threshold Current Increase in GaAs/AlGaAs Quantum Cascade Lasers due to the Thickness Variation
한일기,Jeong, Jin-Wook,송진동,JungIlLee 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.4
GaAs/AlGaAs quantum cascade laser (QCL) epi-structures were grown and lased successfully at 77 K. The thickness variation during the growth sequence was measured by analyzing the transmission electron microscope pictures. The thickness of the epi-layer decreased by up to 80 90 % of its expected value. At least three times higher threshold current and shorter lasing wavelength, compared to the reference QCL, were shown. The decrease in the growth rate during the growth sequence is thought to be a possible reason for such a high threshold current and short lasing wavelength.
화학적 빔 에피탁시에 의한 평면구조에서의 InP/InGaAs 다층구조의 선택적 영역 에피 성장
한일기,이정일,Han, Il-Ki,Lee, Jung-Il 한국진공학회 2009 Applied Science and Convergence Technology Vol.18 No.6
Chemical beam epitaxy 성장법으로 InP/InGaAs 다층구조의 선택적 영역 에피성장 (selective area epitaxy)을 하였다. <011> 방향에 평행한 직선패턴에서는 선폭이 작아지고, <01-1> 방향에 평행한 직선패턴에서는 선폭이 증가하는 현상이 나타났는데 이는 InGaAs의 <311>A와 B면이 <01-1> 방향에 평행한 직선패턴에서 성장되었기 때문으로 설명되었다. 성장속도가 $1\;{\mu}m/h$인 조건에서 5족 가스의 압력이 감소할수록 (100) 면 위에서 평평한 에피층이 성장되었는데 이는 5족 가스의 과포화현상에 의한 3족 원소의 표면이동으로 설명하였다. Selective area epitaxy of multiple-stacked InP/InGaAs structures were grown by chemical beam epitaxy. The width of top of the multiple-stacked InP/InGaAs layer which were selectively grown on the stripe lines parallel to the <011> direction was narrowed, while the width of top of the multiple-stacked InP/InGaAs layer on the stripe lines parallel to the <01-1> was widen. This difference according to the <011> and <01-1> direction was explained by the growth of InGaAs <311>A and B faces on the (100) InP surface on the stripe lines parallel to the <01-1> direction. Under growth rate of $1\;{\mu}m/h$, top of the multiple-stacked InP/InGaAs was flattened as the pressure of group V gas was decreased. This phenomenon was understood by the saturation of group V element on the surface.
한일현(Ilhyun Han),박희경(Heekyeong Park),권대용(Daeyong Kwon),류도영(Doyong Ryu) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
So far, we were considered the noise control of 4 cylinder gasoline engine from a two different standpoint. The first, we should reduce the sound pressure level of the exhaust tail pipe noise, the second, should make the timber of tail pipe noise soft when the interior occupants and somebody in exterior listen the noise. But the exhaust noise was comprised of the engine firing 2<SUP>nd</SUP> order and its harmonics, the half order which was occurred by not being the same length of the exhaust manifold and the exhaust pipe acoustic which was made by the pipe length and the diameter. Because of above stated reasons, the noise made a higher level, a kind of shock and harsh in the exhaust tail pipe, so we were difficult to tune the noise. Therefore, the study analyzed the cause of the exhaust tail pipe noise characteristic and understood the all noise control characteristic of exhaust component. After this, we were able to control the exhaust component to get the low noise level and soft when somebody listen the noise as a proper arrangement of the exhaust component.