• Journal of Power Electronics
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• 제19권5호
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• pp.1315-1325
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• 2019

Aiming at the negative sequence and harmonic problems in the operation of railway static power conditioners, an optimization compensation strategy for negative sequence and harmonics is studied in this paper. First, the hybrid RPC topology and compensation principle are analyzed to obtain different compensation zone states and current capacities. Second, in order to optimize the RPC capacity configuration, the minimum RPC compensation capacity is calculated according to constraint conditions, and the optimal compensation coefficient and compensation angle are obtained. In addition, the voltage unbalance ${\varepsilon}_U$ and power factor requirements are satisfied. A PSO (Particle Swarm Optimization) algorithm is used to calculate the three indexes for minimum compensating energy. The proposed method can precisely calculate the optimal compensation capacity in real time. Finally, MATLAB simulations and an experimental platform verify the effectiveness and economics of the proposed algorithm.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2001년도 추계공동학술대회 논문자료집 정보화 젼략 패러다임의 변화에 대한 보기술의 대응
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• pp.143-143
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• 2001

• 대한설비공학회지:설비저널
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• 제20권3호
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• pp.199-204
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• 1991

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2004년도 하계학술발표 논문집
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• pp.180-180
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• 2004

• 대한설비공학회지:설비저널
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• 제22권4호
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• pp.274-278
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• 1993

• 대한설비공학회지:설비저널
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• 제15권4호
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• pp.303-310
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• 1986

• Journal of Advanced Marine Engineering and Technology
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• 제34권2호
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• pp.332-338
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• 2010

전력계통에서 아크현상이 원인이 되는 전기화재는 전기제품의 사용증가에 따라 급증하고 있으나, 이들 사고를 방지할 수 있는 확립된 방법은 없다. 이들 배경에서 본 논문은 공기조화기에서 직렬아크 검출 기술과 장치에 대한 실험적 결과에 대해 기술하였다. 공기조화기의 불완전한 접속부에서 발생하는 직렬아크를 모의하고, 주파수 스펙트럼을 FFT로 분석한 결과, 190 kHz~250 kHz와 900 kHz~1.6 MHz 에 존재함을 알 수 있었다. 저역차단주파수가 170 kHz이며 60 Hz를 176 dB까지 감쇄시킬 수 있는 아크검출 및 파형정형 회로를 설계하였다. 또한 스위치 조작, 인버터 운전 및 서지 등에 의해 발생하는 노이즈로부터 직렬아크신호를 분리할 수 있는 알고리즘을 제안하였다. 적용실험은 UL1699에 규정 되어있는 아크발생장치를 이용하여 여러 형태의 공기조화기에서 수행되었으며, 99 %이상 검출능력을 나타내었다.

• 한국토양비료학회지
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• 제17권3호
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• pp.224-231
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• 1984

누수(漏水)와 양분용탈(養分溶脫)이 심한 사질답(砂質畓)(강서통(江西統))에 산적토(山赤土), 점질(粘質) 및 미사질해이토(微砂質海泥土)와 영일만(迎日灣)의 제삼기층토양(第三紀層土壤)을 객토처리(客土處理)하여 토양개량효과(土壤改良效果) 및 벼 생육(生育)에 미치는 영향(影響)을 2개년간(個年間) ('80~'81)에 걸쳐 비교(比較)하여 본 결과(結果)는 다음과 같다. (1) 수량(收量)은 1, 2년차(年次) 공히 비슷한 경향(傾向)이었으며 점질해이토구(粘質海泥土區)와 제삼기층토(第三紀層土) 처리(處理區)에서 가장 높았다. (2) 2년차(年次)에서 전생육기간(全生育其間)동안 객토(客土)의 잔효(殘效)에 의하여 건물중(乾物重) 및 무기성분(無機成分) 흡수량(吸收量)은 증가(增加)하는 경향(傾向)이며 특히 점질해이토구(粘質海泥土區)와 제삼기층토구(第三紀層土區)가 현저(顯著)하였다. (3) 시험(試驗) 후(後) 토양(土壤)의 양(陽)이온치환용량(置換容量), 유효규산(有效珪酸), 치환성양(置換性陽)이온 및 황성철함량(活性鐵含量)이 증가(增加)되었으며 제삼기층토구(第三紀層土區)에서 양(陽)이온 치환용량(置換容量)이 가장 높았다. 또 입단함량(粒團含量)과 소성지수(塑性指數)는 증대(增大)되었으며 제삼기층토구(第三紀層土區)와 점질해이토구(粘質海泥土區)에서 투수계수(透水係數)가 현저(顯著)히 적어졌다.

• Journal of Biosystems Engineering
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• 제39권4호
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• pp.253-260
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• 2014

Purpose: This study investigated the harvesting properties of the giant miscanthus (Miscanthus ${\times}$ giganteus) to measure the required mowing power for different stem conditioning methods in order to shorten the drying time after mowing and the bale density so that the crop can be used as biomass in the winter season. Methods: The required mowing power and bale density were measured using a power measurement device, three different mower-conditioners, and a mid-sized round baler under different working speeds and conditioning methods. Results: For the various mower-conditioners, the average stem length from mowing was 0.86-0.91 m, and the available working speed was 1.6 m/s. The steel roller-type mower-conditioner showed better stem conditioning but could not mow over a working speed of 1.6 m/s. The required average power of the mower-conditioners varied from 23.8 kW for the steel roller-type rotary disk mower-conditioner with a working width of 2.4 m to 37.2 kW for the flail-type rotary disk mower-conditioner with a working width of 3.2 m at a working speed of 1.6 m/s. The bale densities were $155.8-172.2kg/m^3$. The highest bale density was measured for stems with no conditioning and a moisture content of 11.3% (d.b.) mowed by the rotary disk mower. The bale density was affected by the mowing method because of the low moisture content of the miscanthus stems. Conclusions: In terms of the working performance and conditioning statue, the steel roller-type mower-conditioner is a better choice at a working width of 2.4 m, while the flail finger-type mower-conditioner is better at a working width of 3.2 m. The type of mower-conditioner used for giant miscanthus harvesting should be determined by considering the harvest area, workable period, and working performance of a mower-conditioner and baler during the winter.

• 대한치과보철학회지
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• 제32권2호
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• pp.268-280
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• 1994

Tissue conditioners have been used for treatment of denture stomatitis caused by wearing of dentures. Early studies pointed out Candide albicans (C. albicans) as main etiologic factor, and antifugal agents were added for control of the species. But there is a little information about broad comparison on the effect of tissue conditioners and antifungal agents added. The purpose of the present study was to compare the inhibiting effect of four tissue conditioners and one temporary soft liner on the growth of C. albicans for treatment of denture stomatitis using gel diffusion method by measuring diameter of the zone of growth inhibition. Three antifungal agents were added to each material for evaluation of the effect of added agents. Finally, observation was made to evaluate the effect of the loss of antifungal elements by aging of the specimen. The results of this study were obtained as follows : 1. Tempo had remarkable antifungal effect showing the zone of growth inhibition as 2.35 mm at 1st day, and was most effective on End: 4th and 7th day from incubation (p<0.05). But Coecomfort, Dura conditioner, Visco-gel, Coe-soft had little antifungal effect from the 1st day of incubation. 2. Nystatin was most effective showing 9.60-12.04 mm of zone of inhibition at the 1st day from incubation. The antifungal properties were reduced to amphotericin B, chlorhexidine and materials without agent (p<0.05), and the effect was diminished by time. 3. As pretreatment with amphotericin B, nystatin, chlorhexidine, Tempo was very effective at the 1st day from incubation showing zone of inhibition as 3.65, 12.04, 4.78 mm with addition of each agent. Dura conditioner had strongest antifungal effect at the next day as 2.86, 5.33, 1.29 mm of zone of inhibition, and yielding results of Coe-comfort, Tempo, Coe-soft was shown at 4th and 7th day from incubation (p<0.05). Taken all together, tissue conditioners have little antifungal effect except Tempo. Formation of the zone of growth inhibition was due to agents amphotericin B, nystatin, chlorhexidine and nystatin was most effective. Conclusively, it is advisable to select material which is effective on the growth of C. albican and consider addition of antifungal agents for treatment of denture stomatitis.