• Journal of Korean Society for Atmospheric Environment
• /
• 제23권E1호
• /
• pp.29-38
• /
• 2007

A cylindrical tube connection that has a voltage difference and is separated electrically by an insulator was modelled. The penetration efficiencies of charged particles passing through the connector tube were investigated. Typically, as the particle size decreases and the applied voltage difference increases, the penetration efficiency decreases. To assess the effect of the electrode geometry, various lengths of electric insulator and aerosol flow rate with a fixed tube length and tube diameter were used when calculating penetration efficiencies. The comparison of penetration efficiencies for various electrode geometry setups suggests that the penetration efficiency can be described as a function of the product of applied voltage and electrical mobility of charged particles. The diffusion loss from this and previous studies are compared. Further, an explicit form for penetration efficiency is provided as a function of a new non-dimensional parameter, $Es(=Z_pV/U_{avg}W);\;P_{es}=0.2{\cdot}{\exp}(-Es/0.6342)+0.8{\cdot}{\exp}(-Es/4.7914)$.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.421-421
• /
• 2012

Graphene has drawn enormous attention owing to its outstanding properties, such as high charge mobility, excellent transparence and mechanical property. Synthesis of Graphene by chemical vapor deposition (CVD) is an attractive way to produce large-scale Graphene on various substrates. However the fatal limitation of CVD process is high temperature requirement(around $1,000^{\circ}C$), at which many substrates such as Al substrate cannot endure. Therefore, we propose plasma enhanced CVD (PECVD) and decrease the temperature to $400^{\circ}C$. Fig. 1 shows the typical structure of RF-PECVD instrument. The quality of Graphene is affected by several variables. Such as plasma power, distance between substrate and electronic coil, flow rate of source gas and growth time. In this study, we investigate the influence of these factors on Graphene synthesis in vacuum condition. And the results were checked by Raman spectra and conductivity measurement.

• 한국표면공학회지
• /
• 제31권2호
• /
• pp.109-116
• /
• 1998

Highly transparent conductive pure and fluorine-doped tin oxide(FT0, $SnO_2$ : F) films have been prepared by low pressure metal organic chemical vapor deposition (LP-MOCVD) from various mixtures of tetramethyitin(TMT) with oxygen or oxygen containing ozone. The properties of TO films have been changed with the variation of gases, flow rate, and substrate temperature. The nsing of oxygen containing ozone instead of pure oxygen, reduced substrate temperature by 100-$150^{\circ}C$ while maintaining same thickness. The films prepared by using ozone showed the resistivity in the range from $10^~2$ to $10^{~3}\Omega$cm, and the mobiiity from 10 to $14\textrm{cm}^2$/Vs. Fluorine-doped tin oxide films had properties such as the resistivity about $10^{-4}\Omega$cm, and the mobility from 14 to $19\textrm{cm}^2$/Vs.

• 전자공학회논문지A
• /
• 제33A권3호
• /
• pp.89-95
• /
• 1996

In this ppaer, temeprature dependent transport and heat transport models have been incorperated to the two dimensional device simulator SNU-2D provides a solid bse for nonisothermal device simulation. As an example to study the nonisothermal problem. we consider SOI MOSFET's I-V characteristics have been simulated and compared with the measurements. It is shown that negative slopes in the Ids-Vds characteristics are casused by the temperature dependence of the saturation velocity and the degradation of the temperature dependence mobility. Also it is shown that the kink effect occurs when impact ionization near the drain produces a buildup of holes in this isolated device island, and the hysteresis is caused by the creation of holes in the channel and their flow to the source.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2016년도 춘계학술발표대회
• /
• pp.209-210
• /
• 2016

최근 SDN (Software-Defined Networks)에 대한 관심이 증가함에 따라 개인, 학교, 연구소에서 쉽고 간편하게 가상의 네트워크를 구성하고 SDN 기반 네트워크를 테스트를 수행할 수 있는 Mininet이 많이 활용되고 있다. 또한, 여러 SDN 컨트롤러 중에서 ONOS 컨트롤러는 OpenSource로 공개되어 GUI를 이용해 네트워크의 전반적인 토폴로지와 Flow 관리를 쉽게 할 수 있는 성숙된 컨트롤러로 인식되고 있다. 본 논문에서는 Mininet과 ONOS 컨트롤러를 이용하여 SDN 네트워크를 구성하고, 노드가 각 스위치를 이동하여 다닐 때에도 통신이 올바르게 유지되도록 컨트롤하는 시나리오를 구현하고 그 실험 결과를 제시하였다.

• 대한전기학회논문지
• /
• 제37권9호
• /
• pp.609-618
• /
• 1988

본 논문에서는 전력 VDMOSFET를 2차원 수치해석하여 I_V특성을 구할 수 있는 computer program을 작성하였고 이 program에 의해서 전력 수직이중확산형 MOS(VDMOS)의 I-V 분포 특성, 전위 및 전자정공 농도 분포특성이 computer simulation되었다. 또 teansconductance, on-resistance 및 표면 이동도 model이 적용된 I_V특성이 simulation되어 실험값 및 선행연구자의 결과값과 비교되었다. 기본 방정식은 유한차등분법(F.D.M)에 의해서 해석되었고 Gummel이 알고리즘과 Mock의 식이 적용 되었다.

• 한국전기전자재료학회논문지
• /
• 제19권6호
• /
• pp.512-518
• /
• 2006

In this paper, we investigated the deposition of pentacene thin film on a large area substrate by Organic Vapor Phase Deposition(OVPD) and applied it to fabrication of Organic Thin Film Transistor(OTFT). We extracted the optimum deposition conditions such as evaporation temperature of $260^{\circ}C$, carrier gas flow rate of 10 sccm and chamber vacuum pressure of 0.1 torr. We fabricated 72 OTFTs on the 4 inch size Si Wafer, Which produced the average mobility of $0.1{\pm}0.021cm^2/V{\cdot}s$, average subthreshold slope of 1.04 dec/V, average threshold voltage of -6.55 V, and off-state current is $0.973pA/{\mu}m$. The overall performance of pentacene TFTs over 4 ' wafer exhibited the uniformity with the variation less than 20 %. This proves that OVPD is a suitable methode for the deposition of organic thin film over a large area substrate.

• 대한산업공학회지
• /
• 제22권4호
• /
• pp.551-565
• /
• 1996

We present the required handover capacity of personal communication service exchange(PCX). We use the flow-based mobility model. The dimension of PCX area and the number of radio port controller(RPC) in a PCX are determined according to the traffic carrying capacity of switching system and RPC. For the rectangular or square-shaped PCX/RPC area and the personal communication service environment with pedestrian traffic, we perform numerical computations to investigate the sensitivity to cell size, portable station(PS) terminating traffic, its density, and its average speed. The results how that the size of PCX/RPC area decreases as the PS terminating traffic and the PS density increase, and the PCX handover capacity required is more than 73,000 in the number of transactions per hour.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제52권12호
• /
• pp.559-561
• /
• 2003

We report a new excimer laser annealing method which successfully results in a single grain boundary formation in the channel of polycrystalline silicon thin film transistor. The proposed method is based on lateral grain growth and employs aluminum patterns which act as selective beam mask and lateral heat sink. The maximum grain size obtained by the proposed method is about 1.6${\mu}{\textrm}{m}$ in the length. The grainboundaries should be arranged parallel with the direction of current flow for the best device performance, so we propose a new device fabrication method and a new poly-Si TFT structure. Poly-Si TFT fabricated by the proposed method exhibits considerably improved electrical characteristics, such as high field effect mobility exceeding 240 $cm^2$/Vsec.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.374-374
• /
• 2010

Charge transfer mechanism of poly(4,4'-aminotriphenylene hexafluoroisopropylidenediphthalimide) (TP6F PI) which exhibits bistable ON and OFF switching has been studied using photoemission electron spectroscopy (PES) and near-edge x-ray absorption fine structure (NEXAFS). Here, we demonstrate novel set-up in which holes are injected by photoemission process instead of direct charge carrier injection via metal electrode. The accumulated charges on the PI surface in the OFF state abruptly flow across the PI film when the bias voltage of a back electrode reaches a specific value, indicating that the film is changed to the ON state. Core level and x-ray absorption spectra probed at charge injection region via photoemission process do not show any evidences implying structural modification of TP6F PI during the phase change. Whereas, in valence band spectra, the highest occupied molecular orbital (HOMO) is shifted toward Fermi level, responsible for improved hole-mobility of TP6F PI of ON state.