• The Journal of the Korean Society for Microbiology
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• v.19 no.1
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• pp.11-24
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• 1984

Shigella remains to be an important enteric pathogen in this country for the present. Moreover, most of the isolates have become multiple resistant to various antibiotics which used to be drugs of choice for shigellosis. This study was made as an attempt to assess the present stage of antibiotic resistance and the incidence and transferability of R factors of Shigella. A total of one hundred and seventeen strains of Shigella isolated from patients in Seoul and provincial area between 1982 and 1983 were tested for their resistant to antimicrobial agents and transmission of R-plasmid. Antibiotic susceptibilities were determined by an agar dilution method. Muller hinton agar were used for the assay of drug resistance and tryptic soy broth were used for propagating medium for conjugation. Shigella isolated found to be one or more antibiotics were considered potential donor of R-plasmid. The following results were obtained. 1. Among 117 strains of Shigella isolated, 111 strains(94.9%) were found to be resistant to one or more drugs tested and 97.3% of these resistant strains were multiply resistant, indicating the multiply resistant strains were more than the single resistant strains. Only six strains were susceptible to all drugs tested. 2. Among 117 strains of Shigella isolated, 107 strains(91.5%) were resistant to Tetracyclin(Tc), 106 strains(90.6%) to Chloramphenicol(Cp) and Streptomycin(Sm), 97 strains(82.9%) to Ampicillin(Ap), 68 strains(58.1%) to Cephaloridine(Cr), 10 strains(8.5%) to Nalidixic acid(Na), 5 strains(4.3%) to Kanamycin(Km) and 2 strains(1.7%) to Rifampicin. No strain was resisfant to Amikacin(Ak) and Gentamicin(Gm). 3. All drug-resistant Shigella strains, except three, were multiply resistant to two or more drugs. Fifty eight strains were resistant to five drugs, followed by 26 strains resistant to dour drugs, 12 strains resistant to three drugs and 11 strains resistant to six drugs. 4. The 73% of multiply drug-resistant Shigella transferred their resistance to E. coli by conjugation and the resistance was considered to be mediated by R-plasmid. Resistance to Nalidixic acid and Rifampicin were not transferred by conjugation to recipient. As for the transferability of resistance to each seperate drug, Ap resistance was transferred with 73.2% frequence and Cm and Tc resistance were transferred with approximately 50-60% frequence whereas Sm and Cr resistance were transferred in 19.1-21.4% The other four drugs resistant failed to transfer their resistance to recipient. 5. As for the incidence and transferability of resistance to each seperate drug, the strains resistant to Tc and Cm were encountered most frequently with the rate of 91-92%, whereas transfer of Tc and Cm were low, 51-52%. The incidence of Sm resistance was very high(90.6%) but transferability of drugs resistance was much lower(25.4%). Though the incidence of Km reristance was much lower(4.3%) transferability of Km resistance was considerably higher(60%). 6. The greater the multiplicity of resistance, the greater was the likelihood that part of all of the resistance markers would be transferable.

• Journal of Sensor Science and Technology
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• v.18 no.1
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• pp.86-94
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• 2009

Temperature measurement capability was inter-compared using the transfer standard platinum resistance thermometers(SPRT) among four laboratories of KRISS. The transfer SPRTs were primarily calibrated at the triple point of water and Ga melting point, then used at inter-comparison experiment. Temperature difference of calibration value between temperature laboratory and length laboratory at $20^{\circ}C$ was -0.7 mK and +2.4 mK at density laboratory. Temperature measured near $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$ at fluid flow laboratory was deviated by $34.2{\sim}80.4\;mK$ from the calibration values of the transfer SPRT. Ga melting points was inter-compared among three laboratories, and the difference of Ga melting points against the standard Ga melting point of temperature laboratory were $0.03{\sim}0.54\;mK$ at length laboratory and 0.02 mK at density laboratory.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.71-80
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• 2015

Steel stiffener is required for reinforcing the structure of the window frame made of versatile but weak PVC material. Steel stiffener however becomes a source of greater heat loss and frequently plays a role of thermal bridge due to its high thermal conductivity. To maintain thermal resistance similar to PVC frame, steel stiffener is perforated to reduce the effective heat transfer area. To compensate the structural strength of the steel stiffener which is weakened by the perforation, the thickness is increased. Increase in thickness will also increase the thermal heat resistance. Five samples which are PVC frame, PVC frame + original steel stiffener, PVC frame + 30% perforated steel stiffener, PVC frame + 50% perforated steel stiffener, PVC frame + 65% perforated steel stiffener are modeled and simulated for 2nd moment of area and thermal resistance. Therm/window version 6.3 is used for thermal analysis. The results show that among the five samples analyzed, PVC frame + 65% perforated steel stiffener best satisfies both structural strength and thermal resistance.

• Journal of IKEEE
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• v.26 no.3
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• pp.373-379
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• 2022

In this paper, since the APD(Avalanche Photo Diode) for LTV(Light to Voltage) conversion uses a high voltage in the operating range unlike other PD(Photo Diode)s, the quenching resistor must be connected in series to prevent overcurrent when using the TIA(Transimpedance Amplifier). In such a case, quenching resistance may affect the transfer function of the TIA circuit, resulting in serious stability. Therefore, in this paper, by analyzing the effect of APD quenching resistance on the voltage and current loop transfer function of TIA, we propose a loop analysis and a method for determining the quenching resistance value to improve stability. TIA circuit with quenching resistance was designed by the proposed method and the stability of operation was verified through simulation and chip fabrication.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.3
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• pp.283-291
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• 2023

The physical properties were analyzed for four gas diffusion layers, and gas diffusion electrodes (GDEs) for the cathode of high-temperature polymer electrolyte membrane fuel cell were fabricated through bar coating with three binder to carbon (B/C) ratios. Among them, The GDE from JNT30-A6P showed a significant change in secondary pore volume at a B/C ratio of 0.31, which had the largest pore volume among all GDEs. In the polarization curve, JNT30-A6P GDE showed the best membrane electrode assembly (MEA) performance with a peak power density of 384 mW/cm² at a a B/C ratio of 0.31. From the distribution of relaxation time analysis, the peak 1 corresponding to mass transfer resistance of oxygen reduction reaction (ORR) was significantly reduced in the JNT30-A6P GDE. This is the result that when the binder content decreased, the volume of the secondary pore increased, and the mass transfer resistance of ORR decreased, which played an essential role in the MEA performance.

• Proceedings of the Korean Geotechical Society Conference
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• 1996.10a
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• pp.81-90
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• 1996

• Journal of Magnetics
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• v.19 no.3
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• pp.291-294
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• 2014

In this paper, we examine the electrical and magnetic properties of three different types of shield materials used for wireless power transfer systems: namely, FeSiAl-composite, NiZn-ferrite, and FeSi-amorphous types. The power transfer efficiency and resistance of an RX coil are measured, while varying the shield thickness. For all three types, a thicker shield provides better power transfer efficiency. Analysis of the measurements shows that the FeSiAl-composite type is suitable for systems with size limitation. In terms of magnetic properties, the FeSi-amorphous type shows the best features, and is suited to high power applications. This work can be used as a guideline to select suitable shielding material in various wireless power transfer systems.

• Membrane and Water Treatment
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• v.4 no.4
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• pp.251-263
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• 2013

The internal reflux effect on dialysis through the retentate phase of a countercurrently cross-flow rectangular module is investigated. Theoretical analysis of mass transfer in cross-flow devices with or without recycling is analogous to heat transfer in cross-flow heat exchangers. In contrast to a device without reflux, considerable mass transfer is achievable if cross-flow dialyzers are operated with reflux, which provides an increase in fluid velocity, resulting in a reduction in mass-transfer resistance. It is concluded that reflux can enhance mass transfer, especially for large flow rate and feed-concentration operated under high reflux ratio.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1154-1161
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• 2016

The heat transfer characteristics between liquid lead bismuth eutectic (LBE) and helium are of great significance for the two-loop cooling system based on an accelerator-driven system (ADS). This paper presents an experimental study on the resistance characteristics and heat transfer performance in a LBE-helium experimental loop of ADS. Pressure drops in the LBE loop, the main heat transfer, and the coupled heat transfer characteristics between LBE and helium are investigated experimentally. The temperature of LBE has a significant effect on the LBE thermo-physical properties, and is therefore considered in the prediction of pressure drops. The results show that the overall heat transfer coefficient increases with the increasing helium flow rate and the decreasing inlet temperature of helium. Increasing the LBE Reynolds number and LBE inlet temperature promotes the heat transfer performance of main heat transfer and thus the overall heat transfer coefficient. The experimental results give an insight into the flow and heat transfer properties in a LBE-helium heat exchanger and are helpful for the optimization of an ADS system design.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.562-566
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• 2010

SOD2-transgenic $T_3$ petunia line (A2-36-2-1-1-35) was treated with different levels of methyl viologen (MV) to determine its resistance to oxidative stress. Four (4) levels of MV (0, 100, 200, and $400\;{\mu}M$) were applied. The SOD2-transgenic $T_3$ petunia line exhibited a very significant oxidative stress resistance at the highest MV concentration ($400\;{\mu}M$) treatment compared to non-transgenic plant. RNA and protein expression of SOD2 transgene and higher parenchyma cell density in the transgenic petunias exhibiting resistance to oxidative stress proves its contribution to the expression of its resistance to oxidative stress.