• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1260-1262
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• 2004

Direct Load Control(DLC) system is a load management program for stablization of electric power supply-demand. It is a series of acts limiting the demand of selected demand side at peak load or other time periods. Recently, power supply-demand instability due to dramatic increase in power usage such as summertime air-conditioning load has brought forecasts of decrease in power supply capability. Therefore heightening the load factor through systematic load management, in other words, Direct Load Control became necessary. By examining the composition and operation of the DLC system, this paper provides conceptional understanding of the DLC system and help in system research.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.488-490
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• 2001

A dispered power system means a little bit of small power generation equipment located near the power-damend areas. Due to no power supply line, such a power source is very favorable for the decrease in loss of electric power supply, in comparison to the giantly focused power source, Because of small power source, this power source also corresponds promptly to the variation of power demend. On the basis of energy saving, environmental reservation, and utilization of natural or unused energy, solar power plants can be introduced into the residence section of cities and small water or wind-power plants near the urban areas. In case of Korea, some wind farm have been introduced into Cheju island, Condensed introduction of several small power sources into an used distribution line may, however, result in a big problem, it is, therefore, necessary that protective-cooporative plans between power quality and distribution line should be introduced for efficient utilization of KEPCO distribution system.

• 한국식품영양과학회지
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• 제45권8호
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• pp.1122-1129
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• 2016

본 연구에서는 아로니아, 블랙커런트, 마키베리의 생리활성을 비교하기 위하여 총폴리페놀, 총플라보노이드, 총안토시아닌 함량, DPPH radical 소거능, ABTS radical 소거능, FRAP 활성, 환원력, tyrosinase 저해 효과, 아질산염 소거능 등을 측정하였다. 총폴리페놀 함량은 마키베리가 73.66 mg GAE/g으로 가장 높게 나타났고 그다음으로 아로니아 59.26 mg GAE/g, 블랙커런트 43.70 mg GAE/g 순이었다. 총플라보노이드 함량도 같은 경향을 나타내어 마키베리 28.08 mg/g, 아로니아 24.26 mg/g, 블랙커런트 16.82 mg/g 순으로 나타났으며, 총안토시아닌 함량은 마키베리가 12.82 mg/g으로 가장 높았고, 아로니아와 블랙커런트가 각각 9.52 mg/g과 8.95 mg/g으로 유의적인 차이를 보이지 않았다. 마키베리는 DPPH 및 ABTS radical 소거능, FRAP, 환원력에서 유의적으로 높은 활성을 나타내었고, 시료 농도 5 mg/mL에서는 양성대조군으로 사용한 ascorbic acid보다 우수한 효과를 보여주었다. 그다음으로는 아로니아가 우수한 활성을 보였으며 블랙커런트는 대부분의 기능성 실험 결과 가장 낮은 활성을 나타내었다. 이상의 결과를 종합하여 볼 때 마키베리는 천연 항산화제 및 건강 기능성 식품재료로서의 활용 가능성이 매우 높을 것으로 생각된다.

• International Journal of Internet, Broadcasting and Communication
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• 제15권4호
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• pp.84-89
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• 2023

Recently, the sixth generation (6G) networks have become tremendous research topics. Intelligent reflecting surface (IRS) technologies have been envisioned, to increase spectrum and energy efficiency for the fifth generation (5G) mobile networks, towards the sixth generation (6G) communications. In this paper, especially for the strongest channel gain user, we investigate the bit-error rate (BER) of non-orthogonal multiple access (NOMA) systems with intelligent reflecting surface (IRS). First, we derive a BER expression in a closed-form of Q functions. Second, we investigate the BER performance improvement of IRS NOMA systems over NOMA systems versus the power allocation. Moreover, we analyze the BER performance improvement of IRS NOMA systems over NOMA systems versus the number of IRS devices. In results, NOMA equipped with IRS technologies could play an important role in the paradigm shift from 5G mobile networks to 6G mobile networks.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1396-1397
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• 2011

The world has problem of petrifaction energy exhaustion and environment pollution. We are looking up various solution plans regarding this problem. Solar power is one of the solution to solve the energy shortage problem. But solar power is affected by insolation. So we study tracking solar power system for the generation of electricity more. In this paper, we compared fixed solar power system with horizontal and vertical tracking solar power system. Two method were on he Maximum Power Point(MPP) using Solar pro.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.149-151
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• 2005

Recently, power supply-demand instability due to the dramatic increase in power usage suchas air-conditioning load at summertime has brought forecasts of decrease in power supply capability. Therefore improving the load factor through systematic load management, in other words, Direct Load Control became necessary. Direct Load Control(DLC) system is kind of a load management program for stabilization of electric power supply-demand. It's purpose is limiting the demand of the demand side selected at peak load or other time periods. The paper presented a Design of Direct Load Controller for control the amount of power demand in demand side. The proposed Controller is cheaper and has ability of storing more power data than pre-existing device.

• 한국조리학회지
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• 제20권5호
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• pp.29-33
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• 2014

In this study, we examined the antioxidant activity of the naturaceutical extract in vitro using total phenolic contents, total flavonoids contents, DPPH radical scavenging activity, reducing power assay, and phenolic acid contents. The total phenolic and total flavonoids contents of naturaceutical extract were 5.46 mg/g, 2.21 mg/g, respectively. The DPPH radical scavenging activity of natraceutical extract varied from 18.77 ($200{\mu}g/mL$) to 3.44 ($1,000{\mu}g/mL$). The reducing power of the natraceutical extract absorbance varied from 1.07 (0.78 mg/mL) to 3.44 (12.5 mg/mL), and reducing power of extract presented a concentration-dependent activity increase. The highest amounts of trans-ferulic acid, p-hydroxybenzoic acid, p-coumaric acid, vanillin, vanillic acid, p-hydroxybenzaldehyde, and trans-cinnamic acid were observed in the naturaceutical extract at the levels of 750.79, 619.75, 531.34, 222.04, 219.28, 107.40, and $89.56{\mu}g/g$, respectively. The results imply that this antioxidant effect of the naturaceuticals extract could be harnessed in the management and prevention of degenerative diseases associated with oxidative stress.

• 한국응용과학기술학회지
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• 제20권4호
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• pp.283-288
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• 2003

Alkaline powder cleaning agents (APCAs) were prepared by blending of $Na_2CO_3$ tetrasodium pyrophosphate (TSPP). sodium orthosilicate (Na-OSi), Na-dioctyl sulfosuccinate (303C), Demol C, and MJU-100A (100A). The physical properties of APCAs tested with steel specimen showed the following results. The cleaning powers of APCA-6 ($Na_2CO_3$ 250g/TSPP 70g/Na-OSi 40g/303C 60g/Demol C 50g/100A 30g mixture) for press-rust preventing oil was 97% and 98% degreasing at 2wt%, $70^{\circ}C$ and $90^{\circ}C$, respectively; for Quenching oil, the cleaning power of APCA-6 was 95% degreasing at 2wt% and $70^{\circ}C$. From the results, it was ascertained that APCA-6 exhibited a good cleaning power. Also low foaming power tests proved that the APCA-6 maintained good defoaming effect.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.2246-2248
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• 1997

This paper presents a high-frequency inverter type high-voltage power supply for X-ray equipments. The high-voltage generator consist of an inverter unit including the SR(Series Resonance) type PSC(Phase-Shifted Control) PWM circuit adopting IGBT as the switching power device and high-voltage unit including the CW(Cockcroft Walton) circuit. When the X-ray equipment is radiographing at large power for a short time, this generator operates through feedback voltage mode control to obtain a high speed leading edge and low ripple. The operating modes and design consideration of the proposed power supply are given. Issues in the design of high-voltage divider for high voltage measuring. Experimental results are presented to verify the performance of the designed power supply for varying load conditions. The proposed apparatus has several advantages, e.g., the fast rising time of tube voltage, accuracy and reduced component size etc.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.707-708
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• 2008

본 논문에서는 초전도 플라이휠 에너지 저장장치 (Superconductor Flywheel Energy Storage System : SFES)의 에너지 변환을 위해 사용된 영구 자석형 전동 발전기(Permanent Magnet Synchronous Motor/Generator : PMSM/G)가 SFES의 에너지 저장효율에 미치는 영향을 평가하였다. SFES 시스템은 YBCO 벌크 초전도체를 이용한 저어널 타입(journal type)의 초전도 베어링을 사용하였으며, 슬롯리스 형 PMSM/G를 사용하였다. PMSM/G의 고정자 코어, 누설 자속 및 감겨진 코일에 의한 저장 에너지 손실을 측정하였다. 사용된 코어의 크기, 누설자속, 및 코일의 적절한 선정을 통하여 저장된 에너지의 손실을 상당히 줄일 수 있음을 확인하였다. 또한 영구자석과 코어가 동시에 회전하는 회전 코어형 전동발전기를 적용하여 에너지 손실을 매우 감소시킬 수 있음을 확인하였다.