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Soft-Switching Three-Level Chopper-Inverter for High-Power Applications

  • Lee, D.H.;Peng, D.;Lee, F.C.;Borojevic, D.
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.56-61
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    • 1998
  • A soft-switching three-level chopper-inverter system was built for high-power applications like Power Conditioning System (PCS) for Superconductive Magnetic Energy Storage (SMES). The system can handle 1800-VDC, 200-A peak, and 250-kW output power. The system was designed to operate with 20-KHz PWM operation with the aid of state-of-the-art zero-current transition type soft-switching. The system is based on the Power Electronics Building Block (PEBB) concept.

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THE EQUIVALENCE OF COMPACTNESS AND PSEUDO-COMPACTNESS IN SOME FUNCTION SPACES

  • Atkins, John;Reynolds, Donald F.;Henry, Michael
    • Kyungpook Mathematical Journal
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    • v.28 no.1
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    • pp.79-82
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    • 1988
  • This paper investigates the relationship between compactness and pseudo-compactness in subsets of C(X) where X is locally compact and first countable. Two primary theorems are proven. First, equicontinuity at a point is proven to be equivalent to the existence of a certain open cover of a pseudo-compact subset of C(X). The second theorem proves the equivalence of compactness and pseudo-compctness for closed subsets F of C(X).

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Optical Scanning Holographic Approach to Three-Dimensional Television

  • Poon, Ting-Chung
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.281-284
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    • 2002
  • We first review a real-time holographic recording technique called optical scanning holography (OSH) and discuss holographic reconstruction using spatial light modulators (SLMs). We then present how the overall system can be used for three-dimensional (3-D) holographic television (TV) system and address some of the issues encountered. Finally, we suggest some techniques to alleviate the issues encountered in such a 3-D holographic TV.

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Comparative serology of human brucellosis in Korea

  • Lee, Sung-Il;Choi, Min-Jung;Hur, Jin;Islam, Md Ariful;Khatun, Mst Minara;Baek, Byeong-Kirl;Lee, Chang-Seup;Kakoma, Ibulaimu;Bolye, Stephen M;Srirangananathan, Nammalwar;Young, Edward John
    • Korean Journal of Veterinary Service
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    • v.31 no.3
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    • pp.331-338
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    • 2008
  • The study was carried out to evaluate the diagnostic efficacy of the tube agglutination test (TAT), enzyme-linked immunosorbent assay (ELISA) and the 2-Mercaptoethanol agglutination test (2-MAT) to detect human brucellosis patients in Korea. We examined 87 serum samples of people in the rural farm areas where bovine brucellosis had been reported. People in this study were divided into seven groups- farmers and their families, veterinarians, veterinary quarantine workers, livestock health control officers, artificial inseminators, livestock traders and healthy control individuals. Among 87 people, 65 were males and 22 were females ranging in age from 13 to 72 years. Of 87 serum samples, ELISA detected 21.84%, TAT detected 11.50% and 2-MAT detected 8.05% Brucella positive sera. Brucella specific IgG ELISA antibody titer was recorder higher in the individuals between the ages of 50 and 65 years. The highest prevalence rate of brucellosis(29.4%) was recorded in the cattle farmers and their family members followed by quarantine veterinary office workers (25%) and practicing veterinarians 01.1%). The majority of the Brucella sero-positive individuals in this study had a history of direct contact with animals.

EFFCTS OF TILLAGE SYSTEMS ON THE QUALITY OF RUNOFF FROM SLUDGE-AMENDED SOILS

  • Mostaghimi, Saied;Bruggeman, Adriana C.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1993.10a
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    • pp.984-993
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    • 1993
  • land application of sewage sludge requires careful monitoring because of its potential for contamination of surface water and groundwater. A rainfall simulator was used to investigated the effects of freshly applied sludge on runoff of sediment and nutrients from agricultural crop lands. Rain was applied to 16 experimental field plots. A three run sequence was used to simulate different initial moisture conditions. Runoff, sediment and nutrient losses were monitored at the base of each plot during the simulated rainfall events. Sludge was surface applied and incorporated at conventionally -tilled plots and surface applied at no-till plots, at rates of 0, 75, 150 kg-N/ha. No-till practices greatly reduced runoff, sediment , and nutrient losses form the sludge treated plots, relative to the conventional tillage practices. Incorporation of the sludge was effective in reducing nutrient yields at the conventionally-tilled plots. This effect was more pronounced during the third rain torm, with wet initial conditions. Peak loadings of nutrients appeared during the rainstorm with wet initial conditions.

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Behavior and modeling of single bolt lap-plate connections

  • Rex, Clinton O.;Easterling, W. Samuel
    • Steel and Composite Structures
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    • v.2 no.4
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    • pp.277-296
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    • 2002
  • A research investigation of single bolt lap-plate connection load-deformation behavior is presented. Each important characteristic of this behavior is evaluated and two methods for analytically approximating the behavior are developed and presented. The first of these methods is a component method in which the behavior of the connection is modeled as a combination of the behavior of the parts. The second method utilizes a number of parametric relationships that relate the connection parameters to coefficients of two non-linear continuous analytical curves. The test results from four independent experimental programs that investigated the behavior of single bolt lap-plate connections are used in the development and verification of these methods.