• Satellite Communications and Space Industry
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• v.15 no.1
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• pp.101-107
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• 2008

IMT-Advanced 서비스는 지난 2007년 10월 WRC-07 회의에서 IMT-Advanced를 위한 새로운 주파수가 할당되고 IMT-Advanced 기술 개발 경쟁이 본격적으로 이루어지면서 차세대 이동통신의 주도권을 잡기 위한 표준화 경쟁도 시작되었다. IMT-Advanced 서비스 및 시스템의 표준화는 ITU가 중심이 되어 2009년 10월까지 후보 기술을 제안 받고 2011년 2월까지 이루어질 예정이다. 한편 3GPP, 2GPP2, IEEE802.16 등 기준 IMT-2000 표준 기술을 제안한 표준화 단체 중심으로 IMT-Advanced 표준 기술 개발 경쟁이 치열하게 전개되고 있다. 지난 2008년 1월에 합의하기로 한 최소 기술 요구사항은 각 표준화 단체를 배경으로 한 국가 및 제조업체사이에 표준화 기술의 의견 차이가 매우 커서 2008년 6월로 미루어졌다. IMT-Advanced 기술 요구 사항은 국내 IMT-Advanced 기술 경쟁력을 확보하는 기준이 되는 문서로서 최소 기술 요구사항의 파라미터 값은 향후 IMT-Advanced 시스템의 개발 및 상용화 시기 그리고 기존 IMT-Advanced 기술 요구 사항에 대한 표준화 단체의 기술 개발 현황과 차이를 확인하고 주요 이슈 및 쟁점을 분석하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.155-156
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• 2008

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.3
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• pp.91-106
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• 2019

The demand for lithium has increased sharply due to the explosive increase in lithium secondary batteries for environment-friendly vehicles (EV: Electric Vehicle, HEV: Hybrid Electric Vehicle, PHEV: Plug-in Hybrid Electric Vehicle). Traditionally, lithium has been produced mainly from lithium-containing minerals and brine, and recently it also has been recovered along with other valuable metals by recycling cathode materials of lithium secondary batteries. In this study, we comprehensively reviewed various recovering precesses of lithium from lithium-containing substances.

• Proceedings of the Korean Vacuum Society Conference
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• 2006.08a
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• pp.60-60
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• 2006

• Journal of Information Display
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• v.1 no.1
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• pp.59-62
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• 2000

The first 9-inch carbon nanotube based color field emission displays (FEDs) are integrated using a paste squeeze technique. The panel is composed of 576 x 242 lines with implementation of low voltage phosphors. The uniform and moving images are achieved only at $2V/{\mu}m$, This demonstrates a turning point of nanotube for large area and full color applications.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.340-343
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• 2002

We report here our recent progress in the development and commercialization of polyfluorenes emitting red, green and blue (ROB) colors as materials for light emitting diodes (LEDs). Our patented version of the Suzuki coupling process has been used to synthesize a variety of fluorenebased homopolymers and copolymers emitting colors across the entire visible spectrum. The optical and electronic properties of the polymers are tailored through selective incorporation of different aromatic units into the polyfluorene backbone. Our latest green emitter, reported herein, provides very efficient devices with a low turn-on voltage of 2.25 V, a peak efficiency of 10.5 Cd/A at 6,600 Cd/$m^2$ at 4.85 V. These devices maintain an efficiency of greater than 10 Cd/A up to 50,000 Cd/$m^2$ and demonstrate very good stability as exemplified by a device half-life of greater than 1,500 hours starting from 1,100 Cd/$m^2$. Considerable progress has also been made with red and blue emitters and will be the subject of this presentation.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.427-427
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• 2012

Ferroelectric-gate field effect transistor based memory using a nanowire as a conducting channel offers exceptional advantages over conventional memory devices, like small cell size, low-voltage operation, low power consumption, fast programming/erase speed and non-volatility. We successfully fabricated ferroelectric nonvolatile memory devices using both n-type and p-type Si nanowires coated with organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] via a low temperature fabrication process. The devices performance was carefully characterized in terms of their electrical transport, retention time and endurance test. Our p-type Si NW ferroelectric memory devices exhibit excellent memory characteristics with a large modulation in channel conductance between ON and OFF states exceeding $10^5$; long retention time of over $5{\times}10^4$ sec and high endurance of over 105 programming cycles while maintaining ON/OFF ratio higher $10^3$. This result offers a viable way to fabricate a high performance high-density nonvolatile memory device using a low temperature fabrication processing technique, which makes it suitable for flexible electronics.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.429-430
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• 2008

We demonstrate coherent x-ray diffraction imaging using table-top x-ray laser at a wavelength of 13.9nm driven by 10-Hz ti:Sapphire laser system at the Advanced Photonics Research Institute in Korea. Since the flux of x-ray photons reaches as high as $10^9$ photons/pulse in a $20{\times}20{\mu}m^2$ field of view, we measured a ingle-pulse diffraction pattern of a micrometer-scale object with high dynamic range of diffraction intensities and successfully reconstructed to the image using phase retrieval algorithm with an oversampling ratio of 1:6. the imaging resolution is $^{\sim}150$ nm, while that is much improved by stacking the many diffraction patterns. This demonstration can be extended to the biological sample with the diffraction limited resolution.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.40.2-40.2
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.61.2-61.2
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• 2007