• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.59-60
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• 2013

슈퍼캐패시터(Super Capacitor) 또는 울트라 캐패시터(Ultra Capacitor) 등으로 불리우는 전기 이중층 캐패시터(EDLC, Electric Double Layer Capacitor)는 기존 콘덴서보다 월등한 용량 특성을 가지며, 전극과 전해질의 화학반응을 이용하던 이차전지들과 달리 주로 계면반응을 사용한 축전원리를 이용하여 높은 출력밀도와 충방전 효율, 무제한에 가까운 사이클 특성을 가지고 있다. 또한 전류변화에 안정적이어서 기존의 이차전지와는 달리 보호회로를 생략할 수 있기 때문에 단순한 회로 구성이 가능하고 전극활물질로서 탄소재를 사용하여 환경 친화적인 특성을 가진 차세대 에너지저장장치라고 할 수 있다. 특히 50만 사이클이라는 우수한 수명특성으로 인해 기존의 이차전지가 사용되기 어려운 다양한 분야에 적용이 늘어가고 있는 추세에 있다.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2971-2976
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• 2008

Recently, there has been growing interest in the oxyfuel combustion cycle since it enables high-purity CO2 capture with high efficiency. However, the oxyfuel combustion cycle has some important issues regarding to its performance such as the requirement of water recirculation to decrease a turbine inlet temperature and proper combustion pressure to enhance cycle efficiency. The purpose of the present study is to analyze performance characteristics of the oxyfuel combustion cycle with different turbine inlet temperatures and combustion pressures. It is expected that the turbine inlet temperature improves cycle efficiency, on the other hand, the combustion pressure has specific value to display highest cycle efficiency.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.4 no.2
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• pp.1-9
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• 1986

The marathon course on road surfaces varies frequently in alignment horizontally and /or vertically. This fact compelled use to use a calibrated bicycle method for the course measurement, and to be required statistical approaches for data processing. This paper deals with the computation of the Seoul Olympic Marathon course lengths measured on May 18, 1986. The concept of safety factor against short course is analyzed for certification, and statistical methods are presented to compute an appropriate safety factor. The results of computation show that the best (lowest) actual measurement provides about 99.95% confidence that the combined lengths of all intervals will not be found short upon an equally accurate remeasurement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.51-56
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• 2011

A test range for a 75tf class gas generator cycle liquid propellant rocket engine is defined. The engine system test range is defined by the performance variation during flight, the dispersion after engine calibration, and additional margin. The component development test range includes the operation range corresponding to the engine system test range and the component performance margin.

• The monthly packaging world
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• s.358
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• pp.65-70
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• 2023

(사)한국패키지디자인협회(회장 강부연)가 '2022 제31회 대한민국패키지디자인대전'의 수상작을 발표했다. 이 공모전은 국내 유일의 포장디자인 공모전으로 대학생부문과 일반부문으로 나뉘어 독창성, 상품의 외관, 기능, 소재, 경제성 등을 심사하여 선정했다. 이번 공모전은 포장디자인 분야 디자이너들의 많은 관심과 호응으로 대학생부문은 10개 대학 177점, 일반부문은 30개 업체 71점이 우수 포장디자인 제품으로 선정되어 포장 디자인의 중요성을 통해 위상을 다시 한 번 드높였다. 출품작들의 주목할 점으로는 친환경 트렌드를 반영한 다수의 제품들이 출품되었다는 것이다. 특히, 코로나19 장기화로 인한 소비패턴과 생활의 변화에 따른 트렌드를 반영한 포장디자인 제품이 대거 출품되어 이목을 끌었다. 올해 '대상'은 서울우유협동조합 골든저지밀크 제품이 선정되었으며, 이외 은상으로 업사이클링에 포커스를 맞춘, (주)신원인팩/페어플레이파머스 농업회사법인 사과 부산물을 활용한 친환경 사과트레이 [업사이클링 : APPLE CLAM(애플클램), 화이트와 메탈릭 컬러 매치를 통한 고급화 이미지를 극대화시킨 디자인 (주)아워홈 AMORIS Charcutrie 등 우수 포장디자인으로 선정되었다. 본지에서는 공모전 일반부문 본상 수상작들을 통해 패키지디자인의 최신 동향을 살펴보도록 한다.

• Journal of the Korean Electrochemical Society
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• v.26 no.3
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• pp.35-41
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• 2023

The carbon-coated silicon monoxide (c-SiO_x), which is a negative electrode active material for lithium-ion batteries (LIBs), has a limited cycle performance due to severe volume changes during cycles, despite its high specific capacity. In particular, the significant volume change of the active material can deform the electrode structure and easily damage the electron transfer pathway. To improve performance and mitigate electrode damage caused by volume changes, we replaced parts of the carbon black conducting agent with carbon nanotubes (CNTs) having a linear shape. The content of the entire conductive material in the electrode was fixed at 10% by mass, and the relative content of CNTs ranged from 0% to 25% by mass to prepare electrodes and evaluate electrochemical performance. As the CNT content in the electrode increased, both cycle life and rate capability improved. Even a small amount of CNT can significantly improve the electrochemical performance of a c-SiO_x negative electrode with large volume changes. Furthermore, dispersing CNTs effectively can lead to achieving the equivalent performance with a reduced quantity of CNTs.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.411-417
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• 2013

To use as an anode material of lithium secondary battery, graphite-silicon composite powders are prepared by ball-milling with silicon nanoparticles (average diameter 100 nm, 0~50 wt%) and graphite powder (average diameter $15{\mu}m$) and their electrochemical properties are examined. As the silicon content increases, the graphite becomes smaller by the ball-milling and amorphous phase appears whereas the silicon do not suffer the change of nanocrystalline phases and embeds within the amorphous phase of graphite. Cyclic voltammetry at low scan rate reveals that typical oxidation peaks of graphite and silicon appear at 0.2~0.35 and 0.55~0.6 V, respectively, with higher reversibility for repeated cycles. In contrast, the high-scan-rate redox behavior is very irreversible for repeated cycles. High irreversible capacity is exhibited in the initial charging-discharging cycles, but it diminishes as the cycle number increases. The saturated discharge capacity achieves about 485 mAh $g^{-1}$ at 50th cycle for the composite of Si 20 wt%. This is due to the formation of amorphous graphite morphology by the adequate composition (C:Si=8:2 w/w), which efficiently buffers the volume change during alloying/dealloying between silicon and lithium.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.61-67
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• 2005

This paper presents the carrier phase DGPS method providing a stable navigation solution under the condition of frequent blockage of the GPS signals. The proposed algorithm reject the channels having large errors using a clock bias drift and then calculated the more accurate solution. By investigating the relation between visible satellites` elevation and their clock bias drift, a proper threshold is set. Simulation shows that the presented result is as good as that of commercial system with real data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.9
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• pp.809-816
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• 2010

An environmental control system is installed to dissipate the thermal load in avionic equipments that are mounted under an aircraft. The operating characteristics of the system change with variations in the control parameters. In this study, an environmental control system was designed and built using R-124 by adopting a vapor compression cycle. The operating characteristics of this system were observed by varying the control parameters, such as refrigerant charging amount, opening of the expansion device, compressor rotation speed, and blower rotation speed. The effect of the control parameters on the environmental control system was analyzed and an optimum control method was identified.

• Journal of the Korean Electrochemical Society
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• v.3 no.3
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• pp.173-177
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• 2000

The synthetic carbon was coated with tin oxide and copper by fluidized-bed chemical vapor deposition method. $(CH_3)_4Sn\;and\;Cu(hfac)_{2s}$ were employed as the metallic organic precursor, respectively. The modified synthetic carbons were used for lithium secondary battery anode to investigate their coating effects on electrochemical characteristics as alternative anode materials for lithium secondary batteries. The electrode which prepared by the synthetic carbons(MCMB) coated with tin oxide gave the higher capacity than that of raw material. Their capacity decreased with the progress of cycling possibly due to severe volume changes. But the cyclability was improved by coating with copper on the surface of the tin oxide coated carbon, which plays an important role as an inactive matrix buffering volume changes.