• 한국환경성돌연변이발암원학회지
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• 제25권2호
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• pp.71-75
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• 2005

Green tea and their major constituents such as catechins are famous materials for their anti-oxidative and anti-carcinogenic activity, but many compounds with reducing power can promote the oxidation in their oxidized form or in the presence of metal ion. We investigated the pro-oxidative effect of the ethanol extract equivalent up to 30mg of dried weight of green tea leaves in four in vitro systems which could be used for detecting DNA damage. Although ethanol extract of green tea did not show significant mutagenicity in Salmonella typhimurium TA102, which is sensitive strain to oxidative stress, it degraded deoxyribose extensively in the presence of $FeCl_3-EDTA$ complex, promoted 8-oxoguanine formation in the live bacteria cell, Salmonella typhimurium TAI04, and cleaved super coiled DNA strand with the help of copper ion. It suggested that green tea, famous anti-oxidative material, can be pro-oxidant according to the condition of extraction or metal existence.

• 대한안전경영과학회지
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• 제14권4호
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• pp.79-83
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• 2012

This study analyzes introduction state of Green SCM technology in domestic and overseas area and suggests how to reduce greenhouse gases of logistics in the future. Thus, introduction state of Green SCM was reviewed by building and integrating logistic-related informatization systems such as WMS and TMS. And how to apply the system to track toxic substance in supply chain was performed to manage toxic substance. Therefore, it will be necessary to develop a device to display and collect vehicle condition & log through OBD-II, which is widely adopted, and hardware to measure, collect, and monitor carbon dioxide emission and power consumption of fixed facilities.

• 대한건축학회논문집:구조계
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• 제34권8호
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• pp.13-18
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• 2018

The purpose of this study was to study on the estimation of green remodeling energy reduction tool in building construction. Green Remodeling Decision System that can predict the energy reduction effect in green remodeling is developed as a tool for simple remodeling of green remodeling considering users' convenience, so that it can quickly and comprehensively determine power peak load reduction factor technology. A preliminary simulation result of a short preliminary remodeling evaluation is DB. It will be developed as a tool that can be easily accessed by users such as web and apps.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.986-989
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• 2002

This paper proposes a new single stage power factor correction (PFC) full bridge converter which operates at continuous conduction mode(CCM). The proposed single stage PFC consists of typical zero voltage switching(ZVS) full bridge DC/DC converter, two transformer auxiliary windings, and two small inductors, and two diodes. Neither additional active switch nor any control circuit are added for PFC resulting in very low cost. The proposed converter provides input power factor correction with CCM control and tight output voltage regulation. All switching devices are operated under ZVS with minimum voltage stress. Operation principle and analysis are explained and verified with computer simulation and experimental results on a 1.2kW, 100kHz prototype.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.690-691
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• 2011

제주 스마트그리드 실증사업은 기기 설치, 시험운전 단계에서 실증운전 단계로 넘어가는 과정 중에 있다. 제주 가상전력시장기반 하에서 수요측 자원의 본격적인 Full-Scale 전력거래가 시작될 예정이며, 거래 수익 최대화를 위해서는 에너지저장장치의 적절한 운영이 필수적으로 요구된다. 당사에서는 에너지저장장치의 시간대별 운영 패턴 도출을 통해 가상전력시장에 참여할 수 있는 에너지저장장치 운영 프로그램을 개발하였다. 본 논문에서는 가상전력시장의 개요, 에너지저장장치 운영 프로그램의 개념과 실행 스케쥴, 그리고 입출력 데이터와 Flow Chart 등에 대하여 기술하였다. 향후 실증단계 진행 중에 신뢰할 만한 Raw Data와 거래 reference를 확보, 분석하고 적용하는 과정을 거치면서 운영 알고리즘을 조금 더 개선해야 할 필요가 있다.

• 한국수소및신에너지학회논문집
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• 제21권3호
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• pp.220-226
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• 2010

The heat transfer performance improvement in closed cooling water system of an electric power generation can be achieved by a corrosion control using corrosion inhibitors. The effect of trisodium phosphate and sodium nitrite upon carbon steel at various $Cl^{-1}$ ion containing water concentrations was examined by an integrated corrosion monitoring system. Nitrite was found to be the most effective inhibitor among tested inhibitors for carbon steel. The inhibiting process is considered as adsorption of nitrite ions in oxide layer which form a passive film on the carbon steel surface.

• 대한전자공학회논문지TC
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• 제47권5호
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• pp.1-8
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• 2010

최근 비약적인 휴대폰의 다기능 세대의 발전에 따라 단말은 보다 많은 기능을 제공하고, 사용자도 점점 증가되는 추세이다. 하지만 이는 최근 대두되는 정보 통신 분야의 Green IT측면에서 휴대폰의 세대 발전을 따져본다면 반색 할 만한 일은 아니다. 휴대폰의 세대가 발전함에 따라 이산화탄소의 배출 감소율이 줄어들며, 현재 거의 포화상태에 도달해 있기 때문이다. 이는 기지국 등의 인프라뿐 아니라 단말기 자체에서 운영 중 전력 소모를 하면서 약 18%의 이산화탄소가 배출되기 때문에 단말기 자체의 전력 소모를 줄이는 일이 Green IT의 화두가 되고 있다. 본 논문에서는 단말기와 기지국 사이의 페이징 과정 중 사용자의 개별적 특성을 고려한 슬롯 인덱스(slot index)의 조절을 통해 단말기 운영 중의 전력 소모를 줄이는 방법을 제안한다. 사용자의 특성은 통화시간대와 통화량에 따라 분류하여 이들에게 각기 다른 슬롯 인덱스를 적용시켜 페이징 시의 전력 소모를 관찰하였다. 이는 평균 80%정도의 소비 전력을 줄일 수 있었으나, 슬롯 인덱스 값이 증가 될수록 통화 품질과 관련된 응답 시간(time response)값이 증가되어 저하된 통화 품질을 얻는 Trade Off가 존재한다. 본 논문에서는 개인별 특성에 따른 페이징 조절에 대한 분석과 함께 Trade Off 해결안으로써 기지국 페이징채널 Power ramping방안을 제안하고 그 영향을 분석하고자 한다.

• 한국세라믹학회지
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• 제52권4호
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• pp.229-233
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• 2015

Currently, the majority of commercial white LEDs are phosphor converted LEDs made of a blue-emitting chip and YAG yellow phosphor dispersed in organic silicone. However, silicone in high-power devices results in long-term performance problems such as reacting with water, color transition, and shrinkage by heat. Additionally, yellow phosphor is not applicable to warm white LEDs that require a low CCT and high CRI. To solve these problems, mixing of green phosphor, red phosphor and glass, which are stable in high temperatures, is common a production method for high-power warm white LEDs. In this study, we fabricated conversion lenses with LUAG green phosphor, SCASN red phosphor and low-softening point glass for high-power warm white LEDs. Conversion lenses can be well controlled through the phosphor content and heat treatment temperature. Therefore, when the green phosphor content was increased, the CRI and luminance efficiency gradually intensified. Moreover, using high heat treatment temperatures, the fabricated conversion lenses had a high CRI and low luminance efficiency. Thus, the fabricated conversion lenses with green and red phosphor below 90 wt% and 10 wt% with a sintering temperature of $500^{\circ}C$ had the best optical properties. The measured values for the CCT, CRI and luminance efficiency were 3200 K, 80, and 85 lm/w.

• 멤브레인
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• 제27권5호
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• pp.441-448
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• 2017

본 연구에서는 다공성 폴리에틸렌 지지체를 기반으로 세 가지 가교제를 혼합 도입한 세공충진 이온교환막을 제조하고 역 전기투석에서 멤브레인의 특성이 발전성능에 미치는 영향을 고찰하였다. 실험 결과, 분자 크기가 다른 가교제를 혼합함으로써 이온교환막의 가교도 및 자유체적이 효과적으로 조절됨을 확인하였으며 상관 분석을 통해 멤브레인의 전기화학적 특성 및 이를 적용한 역 전기투석의 발전성능에 복합적인 영향을 미침을 알 수 있었다. 특히 세공충진 양이온 교환막은 최적 가교조건에서 상용막 대비 동등 이상의 발전 성능을 나타내었으며 음이온 교환막 또한 상용막에 근접하는 우수한 성능을 나타내었다.

• 한국전기전자재료학회논문지
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• 제37권4호
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• pp.400-406
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• 2024

Next-generation wide-bandgap semiconductors such as SiC, GaN, and Ga2O3 are being considered as potential replacements for current silicon-based power devices due to their high mobility, larger size, and production of high-quality wafers at a moderate cost. In this study, we investigate the gradual modulation of chemical composition in multi-stacked metal oxide semiconductor thin films to enhance the performance and bias stability of thin-film transistors (TFTs). It demonstrates that adjusting the Ga ratio in the indium gallium oxide (IGO) semiconductor allows for precise control over the threshold voltage and enhances device stability. Moreover, employing multiple deposition techniques addresses the inherent limitations of solution-processed amorphous oxide semiconductor TFTs by mitigating porosity induced by solvent evaporation. It is anticipated that solution-processed indium gallium oxide (IGO) semiconductors, with a Ga ratio exceeding 50%, can be utilized in the production of oxide semiconductors with wide band gaps. These materials hold promise for power electronic applications necessitating high voltage and current capabilities.