• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.449-449
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• 2010

유기발광소자(organic light-emitting diodes, OLEDs)는 저공정비용, 경량화, 가용성 및 대면적화 등의 장점으로 조명 분야와 디스플레이 분야로의 응용 가능성으로 인해 크게 주목을 받아 왔다. 이러한 OLED 소자의 고효율, 고휘도 및 저소비전력 등을 구현하기 위해서는 전극으로부터 전하 주입 층으로 효율적인 전하 주입이 요구된다. 즉, 각 전극의 폐르미 준위로부터 전하 전도준위대로의 전하주입 장벽이 없어야 한다. 본 연구에서는 홀 주입장벽이 없는 정공주입 층으로 $MoO_x$(molybdenum oxide)가 도핑된 NPB(N, N'-diphenyl-N, N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) 층을 사용하여 hole-only 소자를 제작하고 전류-전압 특성을 통해 양극으로부터 홀주입 층으로의 hole-ohmic 특성을 고찰했다. 또한, 전자 주입장벽이 없는 전자주입 층으로 $C_{60}$(fullerene)/LiF(lithum fluoride)의 이종 층을 사용하여 electron-only 소자를 제작하고 음극으로부터 전자주입 층으로의 전자 ohmic 특성을 조사했다. 또한, 전극으로부터 전하주입 층으로 ohmic 특성을 더 자세히 이해하기 위하여 전하주입 층의 자외선 광방출 스펙트럼(ultraviolet photoemission spectra)을 조사했다. 한편, glass/ITO/$MoO_x$-doped NPB (x%: x=0,25, 50 및 75; 5nm)/NPB (63nm)/$Alq_3$ (37nm)/$C_{60}$ (5nm)/LiF (1nm)/Al (100nm)로 구성된 all-ohmic OLED 소자의 발광특성은 $MoO_x$의 도핑 농도가 25%이상일 때 최적의 특성을 보여줬다. 이러한 현상은 정공주입 층에서 p형 도핑 농도의 증가에 따른 정공 농도의 증가에 기인한다. 또한 $MoO_x$의 도핑 농도의 증가에 따라 정공주입 층의 new gap state와 전극의 페르미 준위의 pinning에 기인한다. 25%의 $MoO_x$을 가진 OLED소자는 7.2V의 낮은 전압에서 $58300 cd/m^2$의 높은 휘도를 보여줬다.

• Fire Science and Engineering
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• v.24 no.6
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• pp.61-68
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• 2010

In this paper, a research and development result for the implementation of single station fixed temperature detector for residential fire prevention is described. The detector was developed for the certification in Japanese market because of very low domestic market situation. It is in the situation that there is no other regulation especially for residential detectors in Korea, Japanese case has been reviewed. Investigation of domestic legal circumstances and a comparative study for the test standard owned by KFI (Korea Institute of Fire Industry & Technology) and JFEII (Japan Fire Equipment Inspection Institute) respectively are also indicated. The detector alarms with a buzzer and an indicating LED. In the implementation ultra low power MCU(Micro Controller Unit) is applied to control the sleeping state and the monitoring state properly with low current consumption. To sense the temperature fast response thermistor is adopted in the design of fixed temperature residential detector. Automatic test function and alarm stop function are also considered in the design. The major factors which influence to current consumption are explained for the purpose of design reference. Main electronics circuit parts related to it's characteristics of the detector are described. It is explained that the measured current and experimental result of the battery discharge can be met over 10 years operation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.600-603
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• 2008

In this paper, a new circuit design named memory-in-pixel for low power consumption of the liquid crystal display (LCD) is presented. Since each pixel has a memory, it is able to express 8 color grades using the data saved in the memory without the operation of the gate and source driver ICs so that it can reduce the power consumption of the LCD panel. A memory circuit consists of modified S-R flip-flop (NAND-type) implemented in the pixel, which can supply AC bias for operating the liquid crystal (LC) with the interlocking clocks (CLK_A and CLK_B). This circuit is more complex than the inverter-type memory circuit, but it has lower power consumption of approximately 50% than the circuit. We have investigated the power consumption both NAND and inverter-type memory circuit using a Smart SPICE for the resolution of $96{\times}128$. The estimated power consumption of the inverter-type memory was about 0.037mW. On the other hand, the NAND-type memory showed power consumption of about 0.007mW.

• Electronics and Telecommunications Trends
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• v.21 no.5 s.101
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• pp.30-39
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• 2006

유비쿼터스 네트워크 시대가 도래함에 따라 위치인식 기반 응용 서비스 요구 증대에 따른 위치인식 무선 개인영역 네트워크(WPAN) 시스템이 주목을 받고 있다. 특히 초광대역(UWB) 기술은 저비용, 저소비 전력으로 통신뿐만 아니라 실내나 음영지역에서 수십 cm급 이내의 정밀한 위치인식/추적 기능을 줄 수 있어, 유비쿼터스 홈을 구축하기위한 핵심 기술로 인식되고 있으며, 저속 위치인식 WPAN 표준인 IEEE 802.15.4a의 물리계층(PHY)으로 채택되었다. 본 원고에서는 위치인식 UWB 기술과 관련한 IEEE802.15.4a 표준화 현황과 기술 동향에 대해서 살펴보고자 한다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1627_1628
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• 2009

도로 교통에서의 보행자 안전을 위해 광양자테 레이저 어레이를 이용한 첨단 교통 신호 시스템 응용 기술을 소개한다. 저소비 전력 및 온도 특성이 뛰어난 광양자테 레이저는 대규모 어레이로 제작이용이하며 고속 모듈레이션 및 색순도 등이 뛰어나 광학 투사 시스템을 이용해 고해상도의 글자체 및 영상 구현이 가능하다. 횡단 보도 인근에 고집적, 고출력의 글자체 광양자테 레이저 어레이를 도로 바닥에 투사 및 영상화 시킴으로써 운전자 및 보행자의 교통 사고 예방에 획기적인 효과를 가져올 것으로 기대된다.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.919-922
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• 2003

This paper presents a novel low power driving circuit for passive matrix organic lighting emitting diodes (OLED) displays. The proposed driving method for a low power OLED driving circuit which reduce large parasitic capacitance in OLED panel only use current driving method, instead of mixed mode driving method which uses voltage pre-charge technique. The driving circuit is implemented to one chip using 0.35${\mu}{\textrm}{m}$ CMOS process with 18V high voltage devices and it is applicable to 96(R.G.B)X64, 65K color OLED displays for mobile phone application. The maximum switching power dissipation of driving power dissipation is 5.7mW and it is 4% of that of the conventional driving circuit.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1250-1254
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• 2008

In this study, A special quality analysis and experiment for low power consumption type pneumatic ISO Solenoid valve was performed. And flow characteristics of the ISO Solenoid valve by stroke change was numerically investigated. As a result, it is shown that magnetic force(2.4N) is exerted enough to move poppet with 0.3mm stroke with 0.01 seconds of response time, and that there is no magnetic force emitted by yoke.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.350-353
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• 1999

This Paper Presents the optimized design of micro-heaters using 501(Si-on-insulator) substrate and oxide-filled trench structure In order to justify a lumped model approximation and thermal boundary assumptions, two-dimensional FDM(finite difference among which conduction is the dominant heat dissipation path. Compared with no-trenchs on the SOI structure, the micro-heaters with trench structures has properties of low heater loss and good thermal isolation. The simulation results show that the heater loss decreases as the number. width and distance of trenchs increases.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.659-661
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• 2011

최근 WPAN 분야의 솔루션인 IEEE 802.15.4a는 저소비 전력으로 통신과 거리측정을 동시에 가능케 하는 PHY 제정을 목표로 하고 있다. 본 논문은 IEEE802.15.4a 물리계층에서 사용하는 UWB 신호를 대상으로 거리인식 시스템을 위한 Link Budget을 분석한다. 거리인식 시스템의 성능은 무선 채널의 다중경로 프로파일에도 관계된다. 따라서 본 연구에서는 IEEE 802.15.4a 채널 특성인 Residential 및 Office 환경을 고려하여 거리인식 시스템을 위한 Link Budget을 분석하였으며 연구된 내용은 다양한 거리추정 방식에 적용하여 거리추정 정밀도 향상에 기여할 수 있을 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1795-1801
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• 2009

In this study, a portable flashlight which can manually generate the electricity by using sunlight was developed so that it can be used in the extreme environmental condition such as no-electricity condition. Battery is charged by using solar battery during the day, but when sunlight is not avalible during the night or rainy day, a handle is rotated to generate the electricity in order to charge the battery manually. To improve the brightness of the light, light is concentrated by using the optical lens. Low electric consumption circuit is used for the longer operating time by suppress electrical consumption while lamp is discharged. A circuit is designed and used for steady electrical curris dand voltage to insure steady battery charging. Super-discharge circuit and protection circuit are used for the super discharge of battery when it is not used for a long time. Also the constant charge is possible by using houseware adapter. As a result, a portable flashlight is designed to charge with sunlight during day, and with houseware adapter during night. A portable flashlight is also designed to irradiate longer distances by improvement of the brightness of the light using the optical lens. Thus, it forms white natural ray of light making possible for night reading.