• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.93-100
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• 2003

Seismic isolation systems can improve the seismic safety of nuclear power plants by decreasing seismic force transmitted to structures and equipment. This study evaluates the effectiveness of equipment seismic isolation systems by the comparison of core damage frequencies in non-isolated and isolated cases. It can be found that the seismic isolation systems increase seismic capacity of nuclear equipment and decrease core damage frequencies significantly. The effect of equipment isolation is more significant in the PGA range of 0.3g to 0.5g.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.11 s.102
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• pp.1106-1113
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• 2005

This paper presents a dual-band mixer for multi-standards of IEEE 802.1la/b/g using a single local oscillator, so as to improve the defects of legacy systems. Those systems have duplicate local oscillators and mixers to handle dual band signals, increasing complexity of system and power loss. The proposed circuit shows 11.6 dB, 16.8 dB of conversion loss and 8.77 dBm, 12.5 dBm of IIP3(Input 3rd Intercept Point) for respective bands when the two RF inputs of 2.452 and 5.260 GHz are down-converted to the identical 356 MHz If frequency. The RF-LO isolations are measured 36 dB, 41 dB at each frequencies and over 50 dB of LO-IF isolations are achieved at all cases.

• The Journal of the Korean Society for Microbiology
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• v.19 no.1
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• pp.55-64
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• 1984

The clinical specimens used in this study were collected during the period from March 4, to December 30, 1983, from children's hospitals in Seoul area. They came from clinically apparent cases of diarrheal disease in hospitals. Many specimens were taken from rectal Swabs. During this period, 2166 stool cultures were streaked onto MacConkey plate and were them deposited in selenite broth. Colonies resembling pathogens on MacConkey medium were picked to KIA, Urea agar, malonate broth, ONPG broth, SIM. Reaction on those media cultures were identified biochemically with using API 20E test kit and confirmed serologically with commercially avabile Salmonella antisera(Difco) or Shigella antisera(Denka, Japan). The sensitivity of Salmonella and Shigella tested to ampicillin cephalosporin, chloramphenicol, colistin, gentamicin, tetracycline, streptomycin, nalidixic acid, neomycin, polymyxin B was performed by means of disc diffusion method recommended by Bauer-Kirby, using the discs prepared in BBL Laboratory. 1. There were 34 (1.6%) isolations of Salmonella cultures and 52(2.4%) isolations of Shigella from the 2,116 specimens. Only 53%of Salmonella were isolated by direct streaking on MacConkey plating media, by contrast, 80% of the Shigella were isolated directly. 2. Shigella flexneri types comprised 56% of the Shigellae isolate from 52 Shigellae identified 24% of Salmonella enteritidis ser typhimurium were identified. 3. Concerning to Salmonella and Shigella occurance according to month and sex, They shows relatively higher for the male than in case of female, and 2-3 age were shown the highest group. 4. October is the month with highest incidences. 5. In the sensitivity patterns of Shigellae, most of them were appeared to be resistant ampicillin, streptomycin, tetracycline, in case of Salmonella, 15% of them were resistant to chloramphenicol.

• Korean Journal of Veterinary Research
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• v.25 no.1
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• pp.53-59
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• 1985

A group of 80 Holstein calves, many with clinical signs of infectious bovine keratoconjunctivitis in summer seasons, was assembled for bacteriologic and ophthalmologic studies at an integrated dairy farm. Observations were started from 1980 to 1984 but bacteriological study was only carried out from thor spring in 1981 and continued during the Autumn in 1981. Corneal lesions and drugs sensitivity were also observed and the results obtained were as follows: 1. Occurrences of IBK-affected cattle during the 5 years were predominent to calves in summer. 2. Among 142 eyes from 80 cattle, 53 isolates of Moraxella bovis(37.3%) were isolated from 37 cattle(46.3%). The prevalence of the infection for clinical eyes were higher than nonclinical eyes calves. 3. Miscellaneous organisms were found from age groups of 5 months to 9 months old. It were 8 hemolytic Neisseria spp., 3 Fungi, Mycoplasma sp. and 1 Pseudomonas sp., but 9 samples were unknown. 4. Prevalence of infection with M. bovis in bilateral clinical eyes were higher than unilateral eyes. 5. Incidence of corneal lesion was predominent in early stage as a watery tears(21.0%) and late stage as a leukomas of corneal opacity(22.8%). 6. The number of isolations of M. bovis and incidence of IBK varied from year to year; Higher incidence of IBK clinical signs were showed in calves from 5 months to 10 months old and the number of isolations of M. bovis was declined in order 8 months(100.0%), 4 months(75.0%), 5 months(66.6%) and 8 months(66.6%) old calves. 7. Chloramphenicol, Nitrofurantoin and Cephalothin were highly sensitive against M. bovis isolates and then Tetracycline, Neomycin, Erythromycin and Kanamycin were intermediate but low sensitive to Streptomycin, Colistin and Penicillin.

• Progress in Superconductivity and Cryogenics
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• v.5 no.2
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• pp.1-7
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• 2003

Nowadays, one of the serious problems in KEPCO(Korea Electric Power Co-Operation) system is the more higher fault current than the SCC(Short Circuit Capacity) of circuit breaker. There are many alternatives to reduce the increased fault current such as isolations of bus ties, enhancement of SCC of circuit breaker, applications of HVDC-BTB(High Voltage Direct Current-Back to Back) and FCL(fault current limiter). But, these alternatives have some drawbacks in viewpoints of system stability and cost. As the superconductivity technology has been developed, the HTS-FCL(High Temperature Superconductor -Fault Current Limiter) can be one of the attractive alternatives to solve the fault current problem. Under this background, this paper presents the EMTDC(Electro-Magnetic Transient Direct Current) model for resistance type HTS-FCL considering the nonlinear characteristic of final resistance value when quenching phenomena occur.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.73-79
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• 2004

Nowadays, one of the serious problems in KEPCO system is the larger fault current than the SCC(Short Circuit Capacity) of circuit breaker. There are many alternatives to reduce the increased fault current such as isolations of bus ties, enhancement of SCC of circuit breaker, applications of HVDC-BTB(Back to Back) and FCL(fault current limiter). However, these alternatives have some drawbacks in viewpoints of system stability and cost. As the superconductivity technology has been developed, the HTS-FCL(High Temperature Superconductor-Fault Current Limiter) can be one of the attractive alternatives to solve the fault current problem. Under this background, this paper presents the EMTDC model for resistive type HTS-FCL considering the nonlinear characteristic of final resistance value when quenching Phenomena occur.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.279-280
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• 1996

This paper reports on the outline and the status of the TAMA-300 project, the 300 meter laser interferometer gravitational wave detector developed by a team of scientists of several research institutes and universities in Japan. In fact the project has been funded and its construction started at the National Astronomical Observatory, Mitaka, in spring 1995. And the constructions of the tunnels for the east-west and north-south arms and of the central building are completed and a half of pipes for laser beams were brought in. Very stable laser oscillator has been almost completed and mew techniques such as vibration isolations, recycling of laser power, and suspension of mirrors by double pendulums have been developed. In fact the purposes of the project are to establish techniques necessary for future km-class detectors and to operate the detector to catch possible gravitational wave events in nearby galaxies such as Andromeda, the target sensitivity being $3 {\times} 10^{-21}$ at 300Hz.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.569-574
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• 2007

The paper presents an application of the model to a practical problem of train-induced vibrations. The aim of this study is to vertify for performance of isolators which was developed in KRRI supported floating slab track. Laboratory tests on developed isolations show that the energy dissipation, under cyclic loading of constant amplitude, can be suitably represented by a combination of a viscous and a hysteretic damping. Also, other tests for structural performance are carried out, such as elastic material test, compression test and so on. The specimen, $400{\times}400{\times}300mm$, is placed between two stiff steel plates designed to uniformly distribute the compression stress on the surface.

• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.16-20
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• 2017

A RF-MEMS (radio-frequency microelectromechanical-system) based DPDT (double pole double throw) switch for the Ku band has been designed and analyzed for this article. The switch topology is based on the FG-CPW (finite ground-coplanar waveguide) configuration of a microstrip-transmission line. An FEM-based multiphysics solver is used for the evaluation of the spring constant, stress distribution, and pull-in voltage regarding the requirements of the switch-beam unit. The electromagnetic performance of the switch is investigated for a $675{\mu}m$ thick silicon substrate. For the operational frequency of 14.5 GHz, an insertion loss better than -0.3 dB, a return loss better than -40 dB, and input/output- and output-port isolations better than -35 dB are achieved for the switching unit.

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.119-122
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• 1980

The udders of 28 culled dairy cows were removed at slaughter and bacteria isolated. Isolations of major known mammary pathogens comparised Staphylococcus sp. (40.7%), non-identified Gram's negative rods (33.2%) and E. coli (7.4%). In the mixed infection, Staphylococcus sp. was most frequently involved. Drug sensitivity tests were performed on several bacterial species by disc method. These tests indicated that the microorganisms isolated from clinical mastitis of dairy cows were more resistant to antimicrobial agents than the organisrms isolated from milk samples.