• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.357-360
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• 2005

Hyundai Motor Company developed the second generation of fuel cell hybrid electric vehicle based on Tucson SUV in 2004. This vehicle has cold start capability below -10C and its driving performances including maximum speed and accelerating time are almost similar to conventional Tucson SUV's performances without any sacrifice in terms of cabin space. Especially. the cold start capability was realized by utilizing only internal power sources such as fuel cell power and high voltage lithium ion polymer battery. In this paper, we will briefly introduce specifications of Tucson FCEV and its driving performances based on field test and simulations.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.289-290
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• 2005

We have investigated the electro-optical (EO) performances of the flexible liquid crystal display (LCD) on twisted nematic (TN) mode according to variation of cell gap in comparison with glass LCD. There were four kinds of cells which were having cell gaps of 3$\mu$m, 4$\mu$m and 5$\mu$m, especially the lowest 2$\mu$m on flexible and glass substrates separately. The EO performances of the flexible cells on the rubbed potyimide (PI) were almost the same those of glass cells. The response time of flexible cells was shorter than that of glass cells but the alignment of liquid crystal (LC) of flexible cells was weaker than that of glass cells. The residual DC of flexible cells was on the increase like that of glass cells in compliance with lowering cell gap.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.526-529
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• 2008

The effect of air impurities on PEMFC performances were studied using electrochemical analysis, such as OCV monitoring, polarization, constant current operation, and electrochemical impedance spectroscopy. The nitrogen dioxide in air lowered the operation voltage at 1 A/$cm^2$ by 160 mV (10 ppm) and 227 mV (100 ppm), while the carbon monoxide effect was relatively not significant (30 mV at 100 ppm). For both nitrogen dioxide and carbon monoxide, the performances were largely recovered when pure air was provided again. Further study for additional air impurities and simulated air are under progress to provide fundamental data for the design of fuel cell vehicles.

• 한국통신학회논문지
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• 제22권9호
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• pp.2014-2026
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• 1997

본 논문에서는 현재 광대역 고속네트워킹의 핵심기술인 비동기 전송방식(Asynchronous Transfer Mode: ATM)을 사용하는 통신 네트워크에서 무선채널을 이용하여 ATM 셀을 전송할 때에 비트오율 성능, 셀손실확률, 셀오류확률 및 네트워크 성능을 분석하였다. 무선 채널에서의 변조방식으로는 대역폭 효율을 높히기 위하여 16Star QAM방식을 적용하였으며, 무선 채널에서의 성능을 개선하기 위한 채널부호화 기법으로는 Reed-Solomon (R-S)부호, 길쌈부호, R-S/길쌈부호의 인쇄부호를 적용하였으며, 효과적으로 ATM셀을 전송하기 위한 UEP(unequal error protection) 부호화 방안으로 부분 연쇄부호를 제시하고 성능을 분석하였다. 이동 무선 통신채널의 특성인 도플러 영향과 라이시안 페이딩 모델을 고려하였고 수신단에서의 성능을 향상시키기 위하여 최대비 결합 방식의 다이버시티 기법을 적용하였으며, 네트워크 성능분석을 위하여는 무선 ATM셀의 셀 전송효율 및 지연시간을 분석하였다. 성능분석 결과로, 부분 연쇄부호를 적용시 기존의 부호화 기법들에 비하여 약 2dB 이상의 ATM 셀 손실 성능 향상을 기대할 수 있으며, 특별히 낮은 오류확률을 요구할 수록 좋은 성능을 보임을 알 수 있었다. 또한 동일한 성능을 얻기 위하여 적용하는 부호화 기법의 오버헤드 비트를 줄일 수 있는 방안임을 확인하였다. 따라서, 부분연쇄부호와 같이 ATM 셀의 헤더와 payload 부분의 에러 보정능력을 달리 적용하는 부호화 기법을 채택하는 것이 미래의 이동통신망에서의 무선 ATM통신을 위한 유용한 전송방식으로 생각된다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.185-185
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• 2006

The performances of proton exchange membrane fuel cell (PEMFC), direct formic acid fuel cell (DFAFC) and direct methanol fuel cell (DMFC) with sulfonated poly(ether sulfone) membrane are reported. Pt/C was coated on the membrane directly to fabricate a MEA for PEMFC operation. A single cell test was carried out using $H_2/air$ gases as fuel and oxidant. A current density of $730\;mA/cm^2$ at 0.60 V was obtained at $70^{\circ}C$. Pt-Ru (anode) and Pt (cathode) were coated on the membrane for DMFC operations. It produced $83\;mW/cm^2$ of maximum power density. The sulfonated poly(ether sulfone) membrane was also used for DFAFC operation under several different conditions. It showed good cell performances for several different kinds of polymer electrolyte fuel cell applications.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.453-454
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• 2006

We studied the nematic liquid crystal (NLC) alignment capability by the IB(Ion bean) alignment method on a NDLC(Nitrogen Diamond Like Carbon) as a-C:H thin film. and investigated electro-optical performances of the IBaligned IPS(In plane switching)cell with NDLC surface. A good LC alignment by IB exposure on a NDLC surface was achieved. Monodomain alignment of the IB aligned IPS cell can be observed. The goodelectro-optical (EO) characteristics of the IB aligned IPS cell was observed with oblique IBexposure on the NDLC as a-C:H thin film for 1 min.

• 한국광학회지
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• 제11권2호
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• pp.130-134
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• 2000

본 논문에서는 명암대비와 밝기를 높일 수 있는 반사형 쌍안정 TN셀의 광학 조건을 최적화 하였다. 세 파장(450 nm, 550nm, 650nm)의 광 특성에 미치는 영향을 살펴보았다. 그 결과 편광판 각도를 다른 광학 파라미터보다 더욱 정밀하게 제어해야 하며, dΔn 값이 밝은 상태의 색 특성에 영향을 미침을 알 수 있었다. 광대역 Ν4 필름을 사용해서 반사형 쌍안정 TN셀을 제작해 10.6:1이라는 명암대비를 얻었다.

• 반도체디스플레이기술학회지
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• 제13권2호
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• pp.37-44
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• 2014

In this study, the performance of dye-sensitized solar cells with different thickness of the photelectrode film was simulated by using the electron-diffusion differential model. Through this simulation, the relationships between the thickness of the photoelectrode film and the performances (open-circuit voltage, short-circuit current density, and overall photoelectric-conversion efficiency) of cells were understood and the performances with different thickness of the photoelectrede film were also examined. For considering the refractive index in the liquid electrolyte and exploring the scattering effect of titanium dioxide particles with different sizes using the Mie light-scattering theory, the highest scattering effect of each particles was found out and the optimal size of the titanium dioxide particle was determined for light scattering in the photoelectrode film of dye-sensitized solar cell. Through experiment, the mixed titanium dioxide cell was better than the single titanium dioxide cell and generated a higher overall conversion efficiency because the optimal titanium dioxide particles in the phoelectrode film as light scattering.

• Journal of Electrochemical Science and Technology
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• 제6권1호
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• pp.26-33
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• 2015

In this study, cell performance and thermal stability of lithium-ion cells with a polyimide (PI) separator are investigated. In comparison to conventional polyethylene (PE) separator, the PI separator exhibits distinct advantage in microporous structure, leading to superior reliability of the cell. The cells with PI separator exhibit good cell performances as same as the cells with PE separator, but their reliability was superior to the cell with PE separator. Especially in the hot-box test at 150 and 180℃, PI separator showed a contraction percentage close to 0% at 150℃, while the PE separator showed a contraction percentage greater than 10% in both width and length. Therefore, the PI separator can be the promising candidate for separators of the next generation of lithium-ion battery.

• 한국차세대컴퓨팅학회논문지
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• 제13권5호
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• pp.104-112
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• 2017

3GPP에서는 HetNet에서 매크로셀과 스몰셀 간 송수신 전력 차이에 따른 트래픽 불균형을 완화하기 위해 업로드 자원이 더 효율적인 스몰셀을 선택하는 CRE (Cell Range Expansion)를 도입하였다. 그리고 이로 인한 신호 간섭 문제 해결을 위하여 ABS (Almost Blank Subframes) 방법이 제안되었다. 본 논문에서는 매크로셀 내의 스몰셀의 개수와 CRE로 확장된 지역에 위치한 단말, 매크로셀 단말의 비율에 따라 ABS 비율을 산출하는 방법을 제안한다. 제안한 방법을 LTESim 시뮬레이터상에 구현하여, 기존에 제안된 방법들과 성능을 비교하였다. 실혐 결과는, 제안된 방법이 기존 방법들과 비교하여 throughput 과 패킷 손실 성능을 향상시킴을 보여준다. 특히 성능 향상이 CRE 경계값에 의하여 달라짐을 보이고, 최적의 성능 개선을 구하기 위한 CRE 경계값이 존재함을 보인다.