• 제목/요약/키워드: H.283

검색결과 373건 처리시간 0.028초

과도 안정도를 고려한 주파수 계전 알고리즘 개발 (The development of frequency relaying algorithm considering a transient stability)

  • 이병현;김철환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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    • pp.282-283
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    • 2006
  • A frequency relaying algorithm which is used system separation and load shedding to improve transient stability is proposed. The algorithm can trip the generator and shed load in the abnormal frequency condition. The computer simulations of load flow analysis is used to determine the amount of load to be shed in an under frequency condition. Furthermore dynamic brake energization in the simulation is performed for the control of overfrequency.

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전력저장용 연축전지의 개발방향 및 현황 (The current status and direction of development of lead acid battey for electric energy storage system.)

  • 천명학;김규태;박진철;김호용;고요;엄영창
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1989년도 하계종합학술대회 논문집
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    • pp.277-283
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    • 1989
  • For the battery energy storage system (BESS), battery is one of most important parts. Various new type batteries for load shifting are under developing. The lead acid battery technology status such as structure, charge and discharge characteristics, life cycle etc. is reviewed and research trend is also introduced.

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THE HEISENBERG INEQUALITY ON ABSTRACT WIENER SPACES

  • Lee, Yuh-Jia
    • 대한수학회지
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    • 제38권2호
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    • pp.283-296
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    • 2001
  • The Heisenberg inequality associated with the uncertainty principle is extended to an infinite dimensional abstract Wiener space (H, B) with an abstract Wiener measure p$_1$. For $\phi$ $\in$ L$^2$(p$_1$) and T$\in$L(B, H), it is shown that (※Equations, See Full-text), where F(sub)$\phi$ is the Fourier-Wiener transform of $\phi$. The conditions when the equality holds also discussed.

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침상형 5Mg(OH)2·MgSO4·3H2O 형성에 관한 MgO와 NH4OH 영향 (Effect of MgO and NH4OH on Formation of 5Mg(OH)2·MgSO4·3H2O Whiskers)

  • 유리;피재환;김형태;김경자;김영웅;김웅;김유진
    • 한국분말재료학회지
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    • 제18권3호
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    • pp.283-289
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    • 2011
  • Magnesium hydroxide sulfate hydrate whiskers ($5Mg(OH)_2{\cdot}MgSO_4{\cdot}3H_2O$, abbreviated 513 MHSH) were prepared using hydrothermal reaction with magnesium oxide (MgO) and magnesium sulfate ($MgSO_4{\cdot}7H_2O$) as the starting materials. The effects of the molar ratio of $MgSO_4$/MgO and amount of $NH_4OH$ were studied. As a result, 513 MHSH whiskers co-existed with hexagonal plate $Mg(OH)_2$ at low concentration of $SO_4^{2-}$. The molar ratio of $MgSO_4{\cdot}7H_2O$/MgO was 7:1, uniform 513 MHSH whiskers were formed without impurity such as $Mg(OH)_2$. Appropriate amount of $NH_4OH$ has affected to formation of high quality MHSH. Their morphologies and structures were determined by powder X-ray diffraction (XRD) scanning electron microscopy (SEM) and thermo-gravimetric analyzer (TGA).

Convenient Assay of O2- Generated on Potato Tuber Tissue Slices Treated with Fungal Elicitor by Electron Spin Resonance - No Secondary Oxidative Burst Induction by H2O2 Treatment

  • Park, Hae-Jun;Doke, Noriyuki
    • The Plant Pathology Journal
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    • 제21권3호
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    • pp.283-287
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    • 2005
  • Since the discovery of generation of $O_2^-$ in plant, many evidence for the oxidative burst (OXB) has been accumulated in various combinations of plant and pathogen or elicitor systems. $O_2^-$ generating system responsible for the OXB was coupled with oxidation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) in microsomal fraction isolated from sliced aged potato tuber slices which were treated by hyphal wall components elicitor from Phytophthora infestans (HWC). We developed new assay method for quantitative measurement of oxygen radical $O_2^-$ by using electron spin resonance (ESR) analysis during elicitor­induced OXB on the surface of plant tissues. The ESR analysis using an $O_2^-$ trapper, Tiron (1,2-dihydroxy-3,5­benzenedisulfonic acid), provided a convenient assay for detecting only $O_2^-$ during elicitor-induced OXB producing various active oxygen species (AOS) on plant tissue surface. Tiron was oxidized to Tiron semiquinon radical by $O_2^-$. Quantity of the radical signal was measured by specific spectra on ESR spectroscopy. The level of $O_2^-$ was high in from surface of potato tuber tissue treated with hyphal cell wall elicitor (HWC) from Phytophthora infestans. There was no secondary OXB induction by $H_2O_2$ treatment in plant.

Korean New Records of Five Bdelloids including Four Rare Species

  • Song, Min Ok
    • 환경생물
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    • 제33권3호
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    • pp.283-289
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    • 2015
  • The bdelloids collected from various terrestrial habitats such as mosses, lichens, mushrooms on tree trunks, leaf litter and soil at four different locations in Korea were investigated. Five bdelloids new to Korea were identified: Macrotrachella inermis Donner, 1965, Macrotrachela magna Schulte, 1954, Macrotrachela oblita Donner, 1949, Habrotrocha eremita (Bryce, 1894) and Habrotrocha schultei Donner, 1965. All these rotifers except M. inermis are new to Asia as well. Remarkably, these five Korean new records included four rare species with poorly known distributions. M. magna and H. schultei are recorded outside their type localities for the first time. M. oblita has been reported only from five European countries, and M. inermis has been known from three European countries and Eastern Turkey before the present study. The taxonomy and distribution of each rare bdelloid are discussed here.

비부착 강연선과 고강도 콘크리트를 적용한 철근콘크리트 외부 접합부의 내진 거동 (Seismic Behavior of RC Beam-Column Exterior Joints with Unbonded Tendons and High Strength Concrete)

  • 권병운;강현구
    • 한국지진공학회논문집
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    • 제19권6호
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    • pp.283-292
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    • 2015
  • In the moment frame subjected to earthquake loads, beam-column joint is structurally important for ductile behavior of a system. ACI Committee 352 proposed guidelines for designing beam-column joint details. The guidelines, however, need to be updated because of the lack of data regarding several factors that may improve the performance of joints. The purpose of this study is to investigate the seismic performance of reinforced concrete exterior joints with high-strength materials and unbonded tendons. Three specimens with different joint shear demand-to-strength ratios were constructed and tested, where headed bars were used to anchor the beam bars into the joint. All specimens showed satisfactory seismic behavior including moment strength of 1.3 times the nominal moment, ductile performance (ductility factor = at least 2.4), and sufficiently large dissipated energy.

탄성체에 접합된 압전 스트립에서의 균열 전파 거동 (Steady State Crack Propagation Behavior in a Piezoelectric Strip Bonded to Elastic Materials)

  • 권순만;최효승;이강용
    • 대한기계학회논문집A
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    • 제26권2호
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    • pp.283-290
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    • 2002
  • In this paper, we consider the dynamic electromechanical behavior of an eccentric Yoffe permeable crack in a piezoelectric ceramic strip sandwiched between two elastic orthotropic materials under the combined anti-plane mechanical shear and in-plane electrical loadings. Fourier transforms are used to reduce the problem to the solution of two pairs of dual integral equations, which are then expressed to a Fredholm integral equation of the second kind. The initial crack propagation orientation for PZT-5H piezoceramics is predicted by maximum energy release rate criterion.