• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.414-419
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• 2002

The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric field is concentrated. In the case of (idled specimens with treating silane, the breakdown strength become much higher Finally, from the analysis of weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1[%], the applied field value needed to be under 21.5 MV/cm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1200-1203
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• 2003

The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were applied to Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased, the stronger breakdown strength became at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric field is concentrated. In the case of filled specimens with treating silane, the breakdown strength become much higher. Finally, according to Weibull distribution analysis, reducing breakdown probability of equipment insulation lower than 0.1% level requires the allowable field allowable field intensity values to be kept under 21.5 MV/cm.

• International Journal of Concrete Structures and Materials
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• v.3 no.2
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• pp.97-101
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• 2009

It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18${\sim}$20%), low strength and insufficient water resistance. Therefore they can not be used as materials for load-bearing structural elements. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block of superficial pores and reduces concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. This effect is attributable to hardening of contacts between silicate binder gel globes and modification of alkaline component owing to "inoculation" of the furan radical. The optimal concrete composition with the increased strength, chemical resistance in the aggressive environments, density and crack resistance was obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.212-217
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• 2002

The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric field is concentrated. In the case of filled specimens with treating silane, the breakdown strength become much higher Finally, from the analysis of weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1[%], the applied field value needed to be under 21.5 MV/cm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.647-651
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• 2001

The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were applied to Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased, the stronger breakdown strength became at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric filed is concentrated. In the case of filled specimens with treating silane, the breakdown strength become much higher. Finally, from the analysis of weibull distribution, it was confirmed that to low allowed breakdown probability under 0,.1%, the applied field value needed to be under 21.5MV/cm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.159-163
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• 2003

In this study, the DC dielectric breakdown of epoxy composites used for PCB material was experimented and then its data were simulated by Weibull distribution equation. The more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical, and the breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised, the electric field is concentrated, and the acceleration of electron and the growth of electron avalanche are early accomplished. From the analysis of Weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1[%], the applied field value needed to be under 21.5[kV/mm].

• Biomolecules & Therapeutics
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• v.14 no.4
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• pp.207-215
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• 2006

Sachungwhan reduced hepatotoxicity induced by carbon tetrachloride($CCl_4$). Improved liver function was observed by measuring the activities of aspartate aminotransferase(AST), alanine aminotransferase(ALT), alkaline phosphatase(ALP), blood urea nitrogen(BUN), creatinine(CRE), total cholesterol(TCHO), triglyceride(TG), low density lipoprotein cholesterol(LDL-CHO), high density lipoprotein cholesterol(HDL-CHO), total protein(TP), albumin(ALB) and total bilirubin(BIL) in serum. Hepatic parameters monitored were levels of cholesterol(CHO), triglyceride(TG), malondialdehyde(MDA), content of cytochrome P450(CYP), level of glutathione(GSH), and activities of NADPH-CYP reductase, superoxide dismutase(SOD), catalase(CAT), glutathione S-transferase(GST), glutathione reductase(GR), glutathione peroxidase(GPx). The histopathological examination showed that the treatment of Sachungwhan relieved the ballooning degeneration of hepatocytes which had been generated by $CCl_4$. The results suggested that hepatoprotective effects of Sachungwhan possibly are due to their promising antioxidative activity.

• Current Applied Physics
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• v.18 no.11
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• pp.1375-1380
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• 2018

Atmospheric-pressure plasma has a great potential in many applications due to its simplicity rather than low pressure plasmas. In material processing, biomedical applications, and many other applications, the input power, gas flow rate, and the geometry of electrode have been mainly considered and studied as important external parameters of atmospheric-pressure plasma control. Besides, since the atmospheric-pressure plasmas are typically generated in an open air, the relative humidity is difficult to control and can change day by day. Therefore, the relative humidity cannot be ignored for plasmas. Thus, in this work, the atmospheric-pressure plasma jet was characterized by changing relative humidity, and it was found that the increase in electron density and OH radicals are due to Penning ionization between helium metastable and water vapors at higher humidity condition.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.95-105
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• 2018

This study empirically test the roles of network closure and structural hole on radical innovation in technological knowledge exchange network in Gumi cluster. In doing so, we build 2,550 firm network, transforming association*firm(2-mode) to firm*firm(1-mode) network data. In addition, in order to investigate firms' attributes, we conduct survey for 101 firms in Gumi cluster using random sampling, and finally collect 86 firm samples. For analysis, we use ridge regression since network density and efficiency, indices of network closure and structural hole respectively, has a high level of multicollinearity. The findings show that structural hole has a significant and positive impact on radical innovation, but network closure has a significant and negative impact on radical innovation. This study contributes to present an empirical evidence of debate on network closure and structural hole based on past conceptual discussions and literature review and further goes a long way towards strategy formulation to establish social capital in accomplishing radical innovation. Further research is required that pays closer attention to features of technological knowledge, innovation types and interaction between network closure and structural hole, directing efforts to structural characteristics of various networks.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.35-47
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• 2019

The mycelial growth of P. coccineus strain was good in PDA and YMA, but mycelial growth was low in MEA. Light irradiation during the incubation period affected the pigment formation and density of mycelia. Mushroom of P. coccineus strain was able to produce fruiting bodies in both bottle and bag cultivation, and oak sawdust was found to be the most suitable substrate for spawn culture and cultivation. In artificial cultivation using sawdust medium, fruiting body was grown to the extent that visual observation was possible from the 15th day, and it formed about 5 days fast in the treatment group with low relative humidity. From 40 to 45 days of mushroom development, mature fruiting bodies could be harvested, and the lower relative humidity of the growing room favored mushroom development and growth. Antioxidant activity of fruiting bodies harvested from artificial cultivation showed that ABTS radical scavenging activity of bottle-cultivated and wild fruit bodies were shown at 505㎍/㎖ and 515㎍/㎖, respectively. However, fruiting bodies harvested in bag cultivation were high at 910㎍/㎖. As a result of DPPH radical scavenging activity, all extracts were found to be inactive, exhibiting IC₅₀ value of more than 2,000㎍/㎖ concentration. The ethyl acetate extract of mushrooms obtained from bottle cultivation showed the highest activity with 1,550㎍/㎖ IC₅₀ value. Methanol extract of wild fruit bodies had the highest ABTS radical scavenging activity at the same concentration (10mg/㎖).