• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1597_1598
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• 2009

In this paper, the techniques and design focus of flexible gain coltrol of LAN(Low Noise Amplifier) using the TSMC 0.18um CMOS process. The design frequency set up a standard on 2.4GHz that is used in Zigbee system. The design concepts a basic Cascode LNA techniques and a swiching circuit consisted of 4 NMOS of load resistance, which convert the output impedenceby tuning on or off. The result show the gain change by NMOS operated swich. The simulation result is that Gain is 10.23~12.96dB and NF(Noise Figure) is 1.41~1.47dB.

• The Korean Journal of Physiology and Pharmacology
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• 제16권4호
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• pp.287-291
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• 2012

This study investigated the effects of proline-serine (PS) and valine-serine (VS) dipeptides on melanogenesis in Mel-Ab cells. Proline-serine and VS significantly inhibited melanin synthesis in a concentration-dependent manner, though neither dipeptide directly inhibited tyrosinase activity in a cell-free system. Both PS and VS down-regulated the expression of microphthalmia-associated transcription factor (MITF) and tyrosinase. In a follow-up study also described here, the effects of these dipeptides on melanogenesis-related signal transduction were quantified. Specifically, PS and VS induced ERK phosphorylation, though they had no effect on phosphorylation of the cAMP response element binding protein (CREB). These data suggest that PS and VS inhibit melanogenesis through ERK phosphorylation and subsequent down-regulation of MITF and tyrosinase. Properties of these dipeptides are compatible with application as skin-whitening agents.

• Journal of Korean Neurosurgical Society
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• 제30권3호
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• pp.358-365
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• 2001

Objectives : Although posterior lumbar fusion operations had been reported to accelerate spinal degeneration, there have been only a few studies for their biomechanical effects. We have studied the change of motion range at the vertebral joint one level above the fusion(UVJ) in pedicle screw fixation group(PSF)(n=13) where facet capsule was destroyed and in posterior lumbar interbody fusion group(PLIF)(n=8) where it was spared. Patients and Methods : The patients were divided into early(3 to 6 months) and late(over 12 months) according to postoperative follow-up period. The flexion, extension and flexion-extension angles(FA, EA, FEA) were measured at the UVJ with pre-operative, early and late post-operative films. Results : Mean age and male to female ratio were $52.7{\pm}9.3$ and 1 : 3.2. Mean follow-up periods were $144.1{\pm}30.0$ and $528.8{\pm}160.3$ days in early and late groups, respectively. The FEA and FA in the late PSF($11.8{\pm}3.1$, $8.5{\pm}2.9$) were significantly greater than pre-operative angles($7.8{\pm}3.9$, $5.1{\pm}3.7$)(p<0.01, p<0.05). All angles in the PLIF showed no significant changes with time. The FEA and FA in the late PSF($11.8{\pm}3.1$, $8.5{\pm}2.9$) were significantly greater than those of the late PLIF($7.6{\pm}2.3$, $3.4{\pm}2.0$)(p<0.01, p<0.001). All angles at early follow-up period were similar between PSF and PLIF. The EA showed no significant change in relation with follow-up period or fusion method. Conclusion : As a result, the facet capsule injury in pedicle screw fixation seems to be related with increased flexion angle or degeneration of the adjacent joint above the fused vertebra in the late phase.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1182-1184
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• 1992

In case of chopper control is used for the d.c motor In the electric vehicle(EV) in general step down chopper is used for the driving and the step-up chopper is used for the regeneration. Bilateral variable ratio chopper system(BVRCS) formed by parallel combination of upper two chopper methods step-down, step-up and step-up/down chopper operations by duty cycle, circuit element and driving condition. In this paper, BVRCS is proposed for the simulated and experimented control of d.c motor in the EV. By the result of simulation BVRCS represents same driving power compared to the step-down and excellent breaking power compared to the step-up chopper system because of the greater motor current.

• 경영과학
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• 제31권1호
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• pp.41-48
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• 2014

This study presents a bottom-up approach for analyzing greenhouse gas (GHG) emissions for the shipbuilding industry in Korea. The overall procedures for deriving GHG emissions from the Korean shipbuilding industry are presented. Based on the long-term forecast on energy demands of the Korean shipbuilding industry, reference energy system (RES) and energy balance (EB) for the shipbuilding process are derived for bottom-up modeling.

• 대한전자공학회논문지
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• 제22권5호
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• pp.50-56
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• 1985

A common failure mechanism in bulk CMOS integrated circuits is the latch-up of parasitic SCR structure inherent in the bulk CMOS structure. Latch-up triggering and holding charac-teristics have been measured in the test devicrs which include conventional and Schottky-damped CMOS structures with various well depths and n+/p+ spacings. It is demonstrated that Schottky-clamped CMOS is more latch-up immune than conventional bulk CMOS. Finally, the simulation results by circuit simulation program (SPICE) are compared with measured results in order to verify the validity of the latch-up modal composed of nan, pnp transistors and two external resistors.

• 정신신체의학
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• 제29권2호
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• pp.176-183
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• 2021

연구목적 응급실 기반 자살시도자 사후관리사업에 등록된 자살시도자의 인구학적 요인, 자살시도 패턴 및 정신건강의학과 병력 및 관리가 사후관리 프로그램 완수에 어떠한 영향을 끼치는지 알아보고자 하였다. 방 법 2018년 6월 1일부터 2021년 5월 31일까지 중앙대학교병원 응급실을 방문한 자살시도 환자 중 사례관리에 동의한 661명을 연구대상으로 하였다. 대상자는 응급실 퇴원 후 8주간의 사후관리 서비스 프로그램에 등록하여 관리를 받았다. 인구학적 요인, 자살시도 패턴, 정신건강의학과 병력 및 관리에 해당하는 요인들을 독립변인으로, 사후관리사업 프로그램의 완수 여부를 종속변인으로 두고, 위계적 로지스틱 회귀 분석을 시행하였다. 결 과 자살시도 패턴이 사후관리 사업 완수에 가장 큰 영향을 미치고, 인구학적 요인, 정신건강의학과 병력 및 관리 순으로 사후관리 사업 완료 여부에 영향을 미치는 것으로 나타났다. 자살시도자 사후관리사업 프로그램 완수자는 미완수자에 비해, 향후 자살계획을 가진 경우가 유의하게 많았고, 자살시도의 진정성이 강했으며, 과거자살시도력 또한 유의하게 높았다. 결 론 대상자들이 사후관리사업 프로그램을 완수하고 지역사회 서비스로 연계되도록 하기 위하여, 자살시도 패턴, 인구학적 요인, 정신건강의학과 병력에 대한 고려를 바탕으로 한 개별화된 접근이 필요하다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.74-76
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• 2001

When a Bus voltage is low, the Load-Flour is generally blown up. If Bus voltage is normalized. the convergence of Load-flow is improved. This paper introduces virtual bus with tap. In that case, the Bus admittance will be considered. And the convergence of Load-Flow in applying virtual bus is debated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.52_53
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• 2009

실시간으로 긴박하게 진행되는 화력발전소의 기동 및 정지시의 각종 운전 조작 시퀀스는 상당 부분이 자동으로 진행된다. 그러나 발전엔지니어들은 모든 시퀀스가 정확하게 진행되는지의 여부에 대한 감시와 판단을 백업(back-up)으로 진행하며 동시에 수동으로 조작해야 하는 기기들에 대해서는 적기에 기기조작을 해야 할 필요성이 있다. 긴박하게 진행되는 수많은 상황들이 모두 제대로 진행되고 있는지를 실시간으로 감시하는 일은 매우 복잡하고 긴장을 요하는 태스크이다. 본 논문은 발전소 기동 시 모든 기기 조작들이 기동 시��스에 따라 정확히 진행되는지의 여부를 지속적으로 감시하고 그 결과를 취합하여 발전 엔지니어들에게 편리하게 요약하여 제공하기 위한 지능시스템 개발에 관하여 기술한다.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.168-174
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• 2024

The electrochemical hydrogen compressor was run under diverse operating conditions in order to probe its capabilities and limitations. It was found that, unlike single-cell operations, the electrochemical hydrogen compressor stack performance improved with a rise in temperature. This improvement in performance was attributed to the gradual weakening of the electro-osmotic drag over time, impacting membrane resistance. As a result of these experiments, compression levels, up to an impressive 120 bar, using the electrochemical hydrogen serial stack were achieved.