• 가정과삶의질연구
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• 제27권4호
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• pp.141-160
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• 2009

Recently, some policies for reducing standby power, which has quite an effect on electricity consumption, have been employed all over the world. This study surveys the present condition of standby power for major electric home appliances during three years and analyzes the result of technical development reducing standby power. It presents how the industry paid attention to applying the technique of reducing standby power to electric appliances and how it affects the product's energy efficiency. We survey the standby power's change for six items, which were selected from the major electric appliances available on the market. It analyzes the difference of standby power consumption between appliances with a standby power reducing technique and those without during the latest three years. The amount of the average standby power is also compared. The comparison data confirms that the industry's effort and application of reducing standby power contribution has contributed to increasing an appliance's energy efficiency. This study restricted the analyzed items to six appliances, which has been a low volunteered involvement in the standby power reducing program. It is important for reducing standby power consumption of appliances because it contributes to saving electric energy at home and abroad. The development of the standby power reducing technique is needed for more appliances. Along with the development of the standby power reducing technique in the industrial field, it also necessary for consumers to enlarge their understanding of standby power reduction for economic, social, and environmental values.

• 한국염색가공학회지
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• 제31권4호
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• pp.249-257
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• 2019

Baker's yeast(Saccharomyces cerevisiae) was used as a biocatalyst for eco-friendly indigo dyeing and the reducing power of yeast according to the alkaline solution type was compared. NaOH solution, lye, and buffer solution were used as alkaline solutions. The reducing power(K/S value, oxidation/reduction potential(ORP), pH) was monitored according to the elapsed time including the initiation of reduction, peak reduction, and the end of reduction. In all alkaline solutions, it was confirmed that yeast can be used reducing agent in indigo reduction dyeing. The pH stability and reducing power of buffer solution was better than that of NaOH alone. Although, pH and ORP stability of the reduction bath in lye were better than that of buffer solution, K/S value in buffer solution was higher compared to lye. The reducing power was different depending on the starting pH of the dye bath, and it was better when starting at pH 10.70 than at pH 11.30. Fastnesses to washing, rubbing, and light were relatively good with above rating 4. There was no significant difference in colorfastness depending on the type of alkaline solutions.

• 동력기계공학회지
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• 제7권1호
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• pp.68-73
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• 2003

The purpose of this study is to develop a new proportional pressure reducing valve and to verify the validity of a new mechanism with pressure control pin. The dynamic characteristics of the object pressure reducing valve was studied by numerical analysis of the mathematical model. Also, static and dynamic characteristics of the new pressure control valve were tested with a testing system based on the test standard.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.107-109
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• 2000

This paper presents an algorithm for reducing congestion cost using decoupled optimal power flow. The main idea of this algorithm is to reduce the reactive power flows on the congested lines in reactive power optimization. New objective function for reducing congestion cost is proposed in the reactive formulation by introducing the shadow prices for congested lines. The proposed algorithm is tested for IEEE 14-bus sample system, and the results are presented and discussed.

• 한국산학기술학회논문지
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• 제17권4호
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• pp.296-302
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• 2016

콘크리트의 내구성 저하로 인한 균열의 보수 및 보강에 소요되는 비용은 콘크리트 구조물의 유지비용 증대로 연결되어 균열발생 저감에 대한 연구가 요구되고 있다. 특히, 전력공급용 시설인 전력구의 경우 지하 매설물이므로 보수 및 보강은 경제적으로 큰 부담이 된다. 그러므로 지하매설 전력구의 경우 효과적인 균열 저감 방안이 설계 초기단계부터 요구되어진다. 본 연구는 전력구용 저수축 콘크리트 제조를 위한 수축저감제 개발의 일환으로 수축저감제 사용 콘크리트의 초기 강도 개선을 위해 TEA를 검토하였다. 검토결과, TEA를 수축저감제의 3% 사용할 경우 조기 강도가 크게 개선되었으며, 수축저감 효과도 우수한 것으로 확인되었다. 또한, TEA 3 %에 수축저감제 2.0 % 혼합하여 적용하였을 경우 압축강도 특성 및 건조수축 길이변화 실험결과에서 가장 우수한 것으로 나타나 수축저감제로서의 가능성을 확인하였다. 추후 수축저감제의 범용적인 적용성 검토를 위하여 수축저감제의 사용재료 변화 등에 대한 다양한 재료변수 요인 검토를 통하여 수축저감제의 성능 검토가 필요할 것으로 사료된다.

• Food Science and Biotechnology
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• 제14권2호
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• pp.212-215
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• 2005

Ethanol crude extracts of wood, bark, leaf, and fruit of Callistenwn citrinus were compared for their antioxidant activities based on DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical-scavenging activity and reducing power. Bark extract showed the most potent radical-scavenging activity and reducing power, showing 94.1 and 0.64% at 25 and $100\;{\mu}g/mL$, respectively. Total phenolic content of the bark extracts (275.0 mg GAE/g) was higher than those of others. Further fractionation of the bark extract using hexane, $CH_2Cl_2$, and EtOAc showed EtOAc fraction had the highest antioxidant activity ($IC_{50}\;6.7\;{\mu}g/mL$) and reducing power (0.82 at $100\;{\mu}g/mL$), with total phenolic content of 611.1 mg GAE/g. Total phenolic contents correlated with antioxidant activity ($R^2\;=\;0.7061$) and reducing power ($R^2\;=\;0.7399$).

• 동력기계공학회지
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• 제14권1호
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• pp.47-52
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• 2010

In this study, Finite Element Analysis have been adopted to analyze reducing stress effect and used to induce the sensitivity of design parameter on various techniques which was used for reducing stress. And so it can be utilized as a data to design on similar model. The effect of reducing stress with respect to change of relief groove radius can be increased by 27.3~18.2 % more than radius of fillet. And if a shoulder fillet radius is larger, additional reducing stress by relief groove radius is not obtained. And there was only little effect on reducing stress by changing the center point of groove radius along horizontal direction. In the case that undercut radius is 1.5mm, Max. Equivalent stress is reduced by 5.71% under bending force and 11.11% under torsion. The best effect of reducing stress at undercut model was yielded when the undercut radius is a forth of difference of stepped shaft radius.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1211-1212
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• 2007

In the PV power system, output of the PV array must contain inherent ripples due to the single-phase inverter. So, the function of maximum power point tracking to increase the output efficiency of PV system is degraded. Therefore, to overcome this problem, this paper presents a control strategy for the reducing ripples of the PV array output in grid-connected photovoltaic power system. The proposed control system consists of two loops; the maximum power point tracking loop using the perturbation and observation method is used to calculate the reference solar array terminal voltage(Vref) for reducing ripples of the PV array output and the PI control loop is used to regulate the solar array output voltage according to the Vref. The performance of proposing control strategy is analyzed by means of the PSCAD/EMTDC simulation and experiment. As a result, we may obtain the high performance of the proposed control strategy.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.202-205
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• 2006

In the PV power system, output of the PV array must contain inherent ripples due to the single-phase inverter. So the function of maximum power point tracking to increase the output efficiency of PV system is degraded. Therefore, to overcome this problem, this paper presents a control strategy for the reducing ripples of the PV array output in grid-connected photovoltaic power system. The proposed control system consists of two loops the maximum power point tracking loop using the perturbation and observation method is used to calculate the reference solar array terminal voltage(Vref) for reducing ripples of the PV array output and the PI control loop is used to regulate the solar array output voltage according to the Vref. The performance of proposing control strategy is analyzed by means of the PSCAD/EMTDC simulation. As a result, we may obtain the high performance of the proposed control strategy.

• 전력전자학회논문지
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• 제15권1호
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• pp.1-8
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• 2010

본 논문은 별도의 PWM-IC없이 저가 구현이 가능한 자려 발진 플라이백 컨버터의 대기전력 저감을 위한 회로를 제안한다. 제안된 자려발진 플라이백 컨버터는 기존 자려발진 플라이백 컨버터의 스위치 초기 동작을 위한 경로에서 발생하는 지속적인 전력손실 문제를 개선하기 위해 DC-Blocking 캐패시터를 삽입한 형태로써 약 1W의 대기전력 저감효과 및 시스템의 전력 변환 효율 향상이 가능하다. 본 논문에서는 제안된 회로의 동작원리를 설명하고, 실제 35W급 전원시스템을 구현하여 기존 회로와의 비교를 통해 제안된 회로의 타당성을 검증한다.