• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.103-103
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• 2003

• Feed Journal
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• v.4 no.12 s.40
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• pp.39-45
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• 2006

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.4
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• pp.162-166
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• 2018

Companies that use automatic feeder systems use multiple feeders in close proximity to each other for mass production. Unlike when the feeder is used independently, it does not oscillate to a value that is set to offset or freeze due to symbiosis caused by asynchronous forces hitting each other. This may result in the shipment being damaged by hitting each other or thrown to one side, preventing the transport from being moved to the next process. Whenever an unstable resonance occurs, the operator must reset the value of each feed controller or operate it several times. To address these problems, this paper proposes synchronization algorithm suitable for feed controllers using multiple units and tests are used to confirm performance improvements.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.1
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• pp.59-65
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• 1997

In this paper, a feedforward amplifier with error correction is designed and implemented. This amplifier is composed of operational amplifier, the performance of which is compared with that of the reference amplifier without feedforward error correction. As a result, the sec¬ondary harmonics level is improved about 10 [dB]. Therefore it is shown that the proposed feedforward amplifier network is to be adopted able for wide - band amplifiers.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.154-157
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• 2002

본 연구는 관성의 변화, 비선형 마찰 등에 견실한 피드포워드 적응 위치제어기를 제안한다. 제안된 적응 위치제어기의 특징은 제어기 적응파라미터가 위치오차에 기준모델의 속도 정보를 받아들여 셀프 튜닝된다. 이것은 과도응답 특성을 향상시키고, 정상상태의 수렴 시간을 줄여 시스템의 성능을 개선시킨다. 시뮬레이션을 통하여 제안된 피드포워드 적응 위치제어기의 동작과 설계 방법의 타당성을 보였다.

• 한국정보통신설비학회:학술대회논문집
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• 2003.08a
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• pp.296-299
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• 2003

본 논문은 IMT-2000 대역에서 동작하는 피드포워드 증폭기의 선형성 개선을 위한 각 증폭기의 이득 평탄도의 영향에 관한 것이다. 피드포워드 증폭기의 동작 특성을 조사하기 위하여 WCDMA 신호를 인가하여 최종 출력 10W에서 성능을 측정하였다. 특히, 피드포워드 증폭기의 선형성 개선에 영향을 미치는 원인 중, 각 증폭기의 이득 평탄도의 변화에 따르는 선형성의 개선 양에 대하여 조사하였다. 전력 증폭기는 40MHz, 오차 증폭기는 40MHz와 80MHz의 대역에서 이득 평탄도를 변화시키면서 선형성의 개선 양을 조사하였으며, 오프셋 5MHz 지점에서 IMSR을 측정하였다. 측정 결과. 20dB 이상의 개선 효과를 나타내기 위해서는 전력 증폭기는 1.5dB 이내, 오차 증폭기는 0.5dB 이내의 이득 평탄도를 가져야 함을 확인하였으며, 오차 증폭기의 이득 평탄도가 선형성 개선에 더 큰 영향을 미침을 확인하였다.

• Feed Journal
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• v.4 no.2 s.30
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• pp.96-98
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• 2006

06년, 사료관련 제도는 무엇이 달라질까? 「피드저널」이 농림부 축산물위생과 조정래 사무관의 도움을 받아 올해부터 달라지는 사료관련 제도들을 돌아보았다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.4
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• pp.317-323
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• 2008

Some surfactants known as biosurfactants, are produced biologically by yeast and bacteria from various substances. They are more effective and environmentally friendly than many other synthetic surfactants. Antimicrobial activities of sophorolipids produced by Candida bombiocola were investigated against various microorganisms. Minimal Inhibitory concentration (MIC) of sophorolipid against S. mutans, C. xerosis, and P. acnes were 0.005, 0.05, and 0.005%, respectively. The antimicrobiological activities were more effective than those of SLS and APG. Skin exfoliating and moisturizing effects of vehicles with the sophorolipids were tested. The skin turnover time of aqueous solution with 0.25% sophorolipids was similar to that of aqueous solution with 5.0% lactic acid. Higher moisturizing effects on skin showed as the concentration of sophorolipids increased. We suggest that the sophorolipids can be used for cosmetics as an antimicrobiological agent and an active materials of skin moisturizing and exfoliating.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.303-307
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• 2019

Sophorolipid is a biological surfactant of the glycolipid structure produced by Candida bombicola, which generally exists as a mixture of acidic and lactonic forms. In this study, we investigated physico-chemical properties, antibacterial activities, and cytotoxicity of the sophorolipid containing more than 96% of the lactonic form, produced by the gene regulation of production strains and application of a metabolic engineering technique. The lactonic sophorolipid showed a weak acidity in the range of pH 3.2~4.6 when diluted in water at the concentrations from 1 to 0.001 wt%. The $pK_a$ value of the lactonic sophorolipid was estimated to be around 4.3 from the acid-base titration curve. The critical micelle concentration (CMC) of the lactonic sophorolipid was $10^{-2}wt%$, at which the surface tension of aqueous solution was reduced to 36 mN/m. The lactonic sophorolipid showed the minimum inhibitory concentrations (MIC) of $1{\times}10^{-3}$ and $5{\times}10^{-3}g/mL$ against Propionibacterium acnes and Corynebacterium xerosis, respectively. The MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay showed that cytotoxicity of the lactonic sophorolipid was ten times lower than that of triclosan.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.84.1-84.1
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• 2005