• 제목/요약/키워드: Neutral System

검색결과 1,099건 처리시간 0.04초

Increase of Antioxidant Activities of Egg White Protein Hydrolysate by Fractionation without Using Toxic Chemicals

  • Park, Eun Young;Sato, Kenji
    • 한국조리학회지
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    • 제24권2호
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    • pp.103-111
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    • 2018
  • The objectives of the present study were to examine the antioxidant activity of autofocusing fractions from egg white protein hydrolysates and obtain higher antioxidant peptide fraction, which could be applied to the food model system. Alkaline protease hydrolysate of egg white protein exerted higher antioxidant activities than other protein hydrolysates and were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without toxic solvents and reagents, which is termed autofocusing. Neutral and basic fractions showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the acidic fractions. The acidic and neutral fractions showed higher hydroxyl (OH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) values than the basic fractions. The acidic fractions showed higher metal chelating activity than basic fractions. Antioxidant activities of some autofocusing fractions except for ORAC showed higher compared to the crude hydrolysate. These results suggest that peptides fractions from egg white protein are effective antioxidant, and that autofocusing could be useful to increase antioxidant activity for application to food system.

Control and Analysis of Vienna Rectifier Used as the Generator-Side Converter of PMSG-based Wind Power Generation Systems

  • Zhao, Hongyan;Zheng, Trillion Q.;Li, Yan;Du, Jifei;Shi, Pu
    • Journal of Power Electronics
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    • 제17권1호
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    • pp.212-221
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    • 2017
  • Permanent-Magnet Synchronous Generators (PMSGs) are used widely in Wind Power Generation Systems (WPGSs), and the Vienna rectifier was recently proposed to be used as the generator-side converter to rectify the AC output voltage in PMSG-based WPGS. Compared to conventional six-switch two-level PWM (2L-PWM) converters, the Vienna rectifier has several advantages, such as higher efficiency, improved total harmonic distortion, etc. The motivation behind this paper is to verify the performance of direct-driven PMSG wind turbine system based-Vienna rectifier by using a simulated direct-driven PMSG WPGS. In addition, for the purpose of reducing the reactive power loss of PMSGs, this paper proposes an induced voltage sensing scheme which can make the stator current maintain accurate synchronization with the induced voltage. Meanwhile, considering the Neutral-Point Voltage (NPV) variation in the DC-side of the Vienna rectifier, a NPV balancing control strategy is added to the control system. In addition, both the effectiveness of the proposed method and the performance of the direct-driven PMSG based-Vienna rectifier are verified by simulation and experimental results.

이탈리아 패션의 미적 특성에 관한 연구 - 베르사체와 아르마니의 작품을 중심으로 - (A Study on the Aesthetic Characteristics of Italian Fashion - Through the Artworks of Versace and Armani -)

  • 나현신
    • 복식
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    • 제54권6호
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    • pp.13-23
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    • 2004
  • To date, Italian fashion rans the top even its rise is far behind Paris and New York. The purpose of this study is to analyze and compare the aesthetic characteristics of the italian fashion through two representative designers who contributed to italian fashion. Italy had unique industrial system and craftsmanship from the history and sense of the beauty and the uniqueness from the culture. After the World War II, Italy started to produce elegant sportswears influenced by the progressive manufacturing techniques and practical culture of America. Italian fashion of 'easy elegance' is spearheaded by Vesace and Armani. The aesthetic characteristics of Italian fashion which are shown in the artworks of them are as follows. First, the characteristics of Versace dated from southern sensibility are sensualism, expressionism, historicism. 1) Sensualism: tight silhouette, overexposure, glamorous form, brilliant color, fabric showing femininity, gaudy accessaries 2) Expressionism: brilliant print and color, trimmings and accessaries 3) Historicism: form and motifs that are shown in the historical costume Second, the characteristics of Armani succeeded from northern tailoring are purism, functionalism, and multi-culturism. 1) Purism: clean lines, architectural and geometric forms, natural body line, neutral tones, luxurious fabric 2) Functionalism: functional form, neutral tone, natural fabrics 3) Multi-culturism: design and motif inferred from ethnic costume As such. competition between two different groups made it possible that Italian fashion occupies a special place in the international fashion system.

디자인 피쳐에 의존하지 않는 솔리드 모델의 수정 (Modification of Solid Models Independent of Design Features)

  • 우윤환
    • 한국CDE학회논문집
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    • 제13권2호
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    • pp.131-138
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    • 2008
  • With the advancements of the Internet and CAD data translation techniques, more CAD models are transferred from a CAD system to another through the network and interoperability is getting a common word in the CAD industry. However, when a CAD model is translated for an incompatible system into a neutral format such as STEP or IGES, its precious feature information is lost. When this feature information is lost, the advantage of feature based modeling is not valid any longer, and modification for the model is purely dependent on geometric and topological manipulations. However, the capabilities of the existing methods to modify these feature-independent models are limited as the modification involves a topological change in the model. To address this issue, we present a volumetric method to modify the solid models in neutral format. First, this method selectively decomposes the solid model to separate the portion of interest called feature volume. Next, the designer modifies the feature volume without concerning a topological change. Finally, the feature volume is united with the original solid model to complete the modification process. The results of test cases are presented to attest the usefulness of the proposed method.

양극성 DC 배전용 3상 3-레벨 컨버터의 누설전류 저감과 NP 전류 제어를 위한 공간벡터 PWM 방법 (Space Vector PWM Method for Leakage Current Reduction and NP Current Control in 3-phase 3-level Converter used in Bipolar DC Distribution System)

  • 이은철;최남섭;김희준
    • 전력전자학회논문지
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    • 제23권5호
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    • pp.336-344
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    • 2018
  • This study proposes a new PWM method for leakage current reduction and neutral point (NP) current control in three-phase three-level converter employed in bipolar DC distribution systems. The proposed PWM method uses medium vectors only when there is no need to control the NP current. Thus, common mode voltages are held constant to realize zero leakage current. Some space vectors that produce low-frequency common mode voltages are employed to minimize leakage currents when the average NP current needs to be a positive or negative value. The proposed space vector PWM is implemented based on barycentric coordinate. The validity of the proposed PWM method is verified by simulations and experiments.

Novel deposition technology for nano-crystalline silicon thin film at low temperature by hyper-thermal neutral beam assisted CVD system

  • Jang, Jin-Nyoung;Song, Byoung-Chul;Oh, Kyoung-Suk;Yoo, Suk-Jae;Lee, Bon-Ju;Choi, Soung-Woong;Park, Young-Chun;Hong, Mun-Pyo
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.1025-1027
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    • 2009
  • Novel low temperature deposition process for nano-crystalline Si thin film is developed with the hyper-thermal neutral beam (HNB) technology. By our HNB assisted CVD system, the reactive particles can induce crystalline phase in Si thin films and effectively combine with heating effect on substrate. At low deposition temperature under $80^{\circ}C$, the HNB with proper incident energy controlled by the reflector bias can effectively enhance the nano-crystalline formation in Si thin film without any additional process. The electrical properties of Si thin films can be varied from a-Si to nc-Si according to change of HNB energy and substrate temperature. Characterization of these thin films with conductivity reveal that crystalline of Si thin film can increase by assist of HNB with appropriate energy during low temperature deposition. And low temperature prcoessed nc-Si TFT performance has on-off ratio as order 5.

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4극 저압차단기 N상 Trip장치를 사용한 영상고조파 안전성 개선방안 (Safely Improving Method to Zero-Harmonics Current with 4-Pole Low Voltage Circuit Breaker Equipped N-phase Trip Device)

  • 기채옥;김주철;최창규
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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    • pp.458-461
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    • 2009
  • 3상 4선식 배전방식에서 비선형 부하증가로 인한 제 3고조파 전류발생은 선로의 중성선 및 기기를 과열시키는 원인으로 작용하고 있다. 따라서 고조파에 의한 역률저하 및 기기, 선로 등을 안전하게 보호할 필요가 있다. 본 논문에서는 제 3고조파 전류로 인한 사고사례를 조사하고 고조파 분석 및 부하 불평형 등을 분석하였다. 이를 통해 가장 경제적인 4극 저압차단기를 사용하여 중성선의 과전류로부터 선로 및 기기를 보호하는 방법을 제시하였다.

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난황유의 지방산 조성에 관한 연구 (Studies on the Fatty Acid Composition of Egg Yolk Oil.)

  • 고무석;김종숙;최옥자;김용두
    • 한국식품조리과학회지
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    • 제13권2호
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    • pp.87-91
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    • 1997
  • 방사구와 비방사구에서 채취한 달걀 난황을 배소·압착하여 얻은 난황유를 Folch법으로 정제한 후 gas chromatography로 지방산 조성을 분석한 결과는 다음과 같다. 난황유의 총지질과 중성지질의 지방산 조성은 oleic acid, palmitic acid, linoleic acid 순으로 주성분을 이루었고, 당지질은 palmitic acid, oleic acid, stearic acid, lauric acid 순으로, 인지질은 oleic acid, lauric acid, palmitic acid 순으로 주성분을 나타냈다. 포화지방산 함량은 방사구 보다 비방사구에서 약간 높았고, 포화지방산에 대한 불포화지방산의 비율(USFA/SFA)은 비방사구보다 방사구에서 높았다.

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MATLAB/Simulink에서 계통연계 풍력발전시스템의 특성해석에 대한 시뮬레이션 (Simulation for Characteristics Analysis of Grid-connected Wind Power Generation System on MATLAB/Simulink)

  • 노경수;안해준
    • 조명전기설비학회논문지
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    • 제22권8호
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    • pp.18-25
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    • 2008
  • 본 논문은 HATLAB/Simulink에서 계통연계 풍력발전시스템의 특성해석을 위한 모델링을 제안하여 시뮬레이션을 수행한다. 이를 위해 풍속의 변화에 따른 발전기의 출력제어를 위해 피치제어를 수행하며, 연계변압기의 결선방법에 따른 고장전류의 변화를 살펴봄으로 하여 연계변압기의 결선방법과 고장전류와의 상관관계를 제시하였다. 아울러 풍력발전시스템의 연계변압기 중성점접지방식이 고장전류에 미치는 영향을 살펴본다. 계통에서의 1선 지락고장에 대해 연계변압기의 4가지 결선방식의 차이에 따른 고장전류, 전압 및 발전기의 특성 변화를 확인할 수 있었으며 중성점 접지방식의 차이에 따른 고장전류의 변화를 확인하였다. 사례연구를 통하여 제안한 Simulink에서의 시뮬레이션 모델의 효용성을 입증하였다.

제어 자유도를 한 차원 증가시킨 순시무효전력 보상이론 (Instantaneous Reactive Power Compensation Theory Increasing The Control Freedom One Degree Higher)

  • 김효성
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 F
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    • pp.2481-2483
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    • 1999
  • This paper proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers $q_{q}$, $q_{r}$ were defined. The three power components are linearly independent, so the compensation for the two instantaneous reactive powers leads to control the two components of the current space vector. With the theory, the neutral current of a three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storage element.

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