• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.257-258
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• 2009

This study is about the correlation between KS F 2711 and NT Build 492, and about the effectof hydration accelerating admixture. For this study, various types of binder are tested.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.197-198
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• 2010

The purpose of this study is to compare chloride attack resistibility of light weight aggregate concrete to chloride attack resistibility of normal concrete and confirm the utility. As a result, light weight aggregate concrete's chloride attack resistibility is lower than normal concrete's chloride attack resistibility.

• Journal of the Korea Institute of Building Construction
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• v.12 no.3
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• pp.315-322
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• 2012

The effect of ground granulated blast-furnace slag(GGBS) and alkali activator compressive strength, resistance of chloride attack and freezing-thawing is assessed to develop high volume slag concrete, the replacement rate of GGBS of which is more than 80 percent. result, as the replacement rate of GGBS increases, the compressive strength development properties of concrete in early and long term age decreased and resistance chloride attack and freezing-thawing is increased. The early strength development property, however, is extremely advanced by addition of the alkali activator, which is also found to improve resistance chloride attack and freezing-thawing.

• Journal of Life Science
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• v.23 no.1
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• pp.1-7
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• 2013

Understanding salt tolerance mechanisms is important for the increase of crop yields, and so, several screening approaches were developed to identify plant genes which are involved in salt tolerance of plants. Here, we transformed the Arabidopsis cDNA library into a salt-sensitive calcineurin (CaN)-deficient ($cnb{\Delta}$) yeast mutant and isolated the colonies which can suppress salt-sensitive phenotype of $cnb{\Delta}$ mutant. Through this functional complementation screen, a total of 34 colonies functionally suppressed the salt-sensitive phenotype of $cnb{\Delta}$ yeast cells, and sequencing analysis revealed that these are 9 genes, including CaS, AtSUMO1 and AtHB-12. Among these genes, the ectopic expression of CaS gene increased salt tolerance in yeast, and CaS transcript was up-regulated under high salinity conditions. CaS-antisense transgenic plants showed reduced root elongation under 100 mM NaCl treatment compared to the wild type plant, which survived under 150 mM NaCl treatment, whereas CaS-antisense transgenic plant leaves turned yellow under 150 mM NaCl treatment. These results indicate that the expression of CaS gene is important for stress tolerance in yeast and plants.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.818-829
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• 2016

This study evaluated the responses of 18 potato cultivars to three levels of salinity stress (electrical conductivity, EC: 1.0, 4.0, and $8.0dS{\cdot}m^{-1}$). Stem, leaf, root, chlorophyll, tuber yield, and proline content were investigated and statistically analyzed using analysis of variance (ANOVA) and correlations. Stem number and stem diameter were not affected by salinity, but stem length and aerial weight showed highly significant responses to salinity. Aerial weight decreased with increasing salinity levels in most cultivars, while it increased in some the cultivars 'Daejima', 'Goun', 'Haryeong', and 'LT-8'. Leaf number, leaf area index, and leaf weight were most significantly affected by salinity and the cultivar ${\times}$ salinity interaction. Root length, root weight, total chlorophyll and chlorophyll a were affected by salinity, but not by the cultivar ${\times}$ salinity interaction. The opposite trend was shown in chlorophyll b. Although there was great variability among cultivars, tuber yield decreased in all cultivars, and was most significantly influenced by salinity and the cultivar ${\times}$ salinity interaction. 'Superior', 'Kroda', 'Romana', and 'Duback' gave better tuber yields under salinity at EC 4.0 and $8.0dS{\cdot}m^{-1}$ than the cultivars with better aerial weights. Proline content was increased by salinity in all cultivars, and was more remarkable in the cultivars with better aerial weights than in cultivars such as 'Superior' and 'Kroda' with better tuber yields. Leaf number, leaf area index, leaf weight, and root length parameters were considered to be useful criteria in the evaluation of salt tolerance because of their high positive correlation with tuber yield; however, given its negative correlation with tuber yield under high salinity, proline content was not. Salinity tolerances varied greatly among potato cultivars. The low correlation between growth and yields of aerial parts under high salinity suggests that, in commercial agriculture, it might be more practical to compare relative yields to controls. Additionally, 'Superior', 'Kroda', 'Romana', and 'Duback' might be very useful cultivars to use in breeding programs to develop salinity-tolerant potatoes, as well as for sustainable potato production in saline areas.

• Journal of the korean veterinary medical association
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• v.47 no.1
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• pp.47-54
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• 2011

최근 몇년간 국립수의과학검역원에서 조사한 바에 따르면, 국내 젖소에서 유방염을 일으키는 주된 원인균은 황색포도상구균을 제외하고는 거의 대부분 젖소의 환경으로부터 유래하는 환경성 세균에 의한 것으로 확인된 바 있다. 국내 젖소의 유방염 원인균으로 작용하고 있는 이러한 환경성 세균 중 coagulase-음성 포도상구균 (Coagulase-negative Staphylococci, CNS)과 E. coli 등의 그람 음성균이 가장 많은 비율을 차지하였지만 그 외에 Streptococcus uberis를 비롯한 환경성 연쇄상 구균과 장구균도 상당한 비율을 차지하는 것으로 조사되었으며 이에 대해서는 지난 9월호에서도 상세히 기술한 바 있다. 환경성 연쇄상구균과 장구균은 젖소에서 유선감염 및 임상형 유방염의 중요한 원인이며 환경성 연쇄상구균 중 가장 흔히 발견되는 유방염 원인체는 Streptococcus uberis 로서, 이는 국내에서뿐만 아니라 미국, 유럽, 뉴질랜드, 호주 등에서 수행된 많은 연구결과에서도 마찬가지로 나타났다. 장구균 중 가장 흔히 분리되는 균종은 E. faecium과 E. faecalis로서 검역원에서 지난 몇 년간 조사된 결과에서도 이 두 가지 균 종이 유방염우유에서 분리된 장구균의 90% 이상을 차지하였다. 이러한 환경성 연쇄상구균과 장구균은 사람과 동물의 장관, 분변, 감염된 유방 및 전체적인 목장 환경에서 분리되고 있다. 장구균은 일반적으로 환경성 연쇄상구균/장구균 유방염 감염증 중의 일부일뿐이고 장구균에 의한 유방염이 목장의 주된 문제가 되는 일은 비교적 드물다. 현재, 장구균에 의해 발생하는 유방염은 S. uberis를 통제하기 위해 사용되는 방법과 동일한 방법으로 통제할 수 있다고 여겨진다. 원인체에 상관없이 유방염을 통제하기 위한 기본적인 원칙은 유방염을 일으킬 수 있는 병원체에 유두끝이 노출되는 기회를 줄이거나 감염에 대한 젖소의 저항성을 증가시키는 두 가지 방법이다. 역으로 얘기하면, 병원체에 대한 유두끝 노출을 증가시키거나 감염에 대한 젖소의 저항성을 감소시키는 요인들은 우군 내에서 더 많은 유방염을 발생시킬 가능성이 높기 때문에 위험요인으로 간주된다. 본 고에서는 환경성 연쇄상구균에 의한 유방염과 관련이 있는 것으로 알려진 이러한 여러 가지 위험요인들에 대해 알아보고 그러한 위험요인을 줄일 수 있는 방법에 대해서도 고찰하고자 한다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.173-180
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• 2013

This paper is to investigate an effect of waste cooking oil(WCO) on the engineering properties and durability of high volume admixture concrete. Fly ash with 30% and blast furnace slag with 60% were incorporated in OPC to fabricate high volume admixture concrete with 0.5 of W/B. Emulsified refining cooking oil(ERCO) was made by mixing WCO and emulsifying agent to improve fluidity. ERCO was replaced by cement from 0.25 to 1.0%. As results, the increase of ERCO resulted in decrease of slump and air contents. For compressive strength, the use of ERCO led to decrease the compressive strength at 28 days, while it had similar strength or much higher strength than plain concrete at 180 days. Resistance to carbonation and chloride penetration was improved with the increase of ERCO contents due to decreased pore distribution by saponification between ERCO and concrete, while freeze-thaw resistance was degraded due to air loss.

• Journal of the Korea Concrete Institute
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• v.16 no.3 s.81
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• pp.303-310
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• 2004

The purpose of this study was to investigate the effect of using method and replacement ratio of limestone powder and water-cement ratio on the compressive strength and the resistance to sulfate attack of mortar incorporating limestone powder as fundamental study to use limestone powder as an addition for concrete. As a results, The method using limestone powder as a part of cement showed decrease of the compressive strength of mortar. The strength of mortar incorporating limestone powder almost decided upon unit cement content. It was recognized that the method replacing limestone powder as a part of cement was effective to decrease the heat of hydration in concrete. The method using limestone powder as a part of fine aggregate showed the considerable increase of the strength and resistance to sulfate attack of concrete. Furthermore, it was recognized that the method using limestone powder as a part of fine aggregate were effective materials as an addition for concrete in view of the improvement of strength and resistance to sulfate attack.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.748-755
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• 2013

This study was conducted to find a salt tolerance gene in Brassica rapa. In order to meet this objective, we analyzed data from a KBGP-24K oligo chip [BrEMD (Brassica rapa EST and microarray database)] of the B. rapa ssp. pekinensis 'Chiifu' under salt stress (250 mM NaCl). From the B. rapa KBGP-24K microarray chip analysis, 202 salt-responsive unigenes were primarily selected under salt stress. Of these, a gene with unknown function but known full-length sequence was chosen to closely investigate the gene function. The selected gene was named BrSSR (B. rapa salt stress resistance). BrSSR contains a 285 bp open reading frame encoding a putative 94-amino acid protein, and a DUF581 domain. The pSL94 vector was designed to over-express BrSSR, and was used to transform tobacco plants for salt tolerance analysis. T1 transgenic tobacco plants that over-expressed BrSSR were selected by PCR and DNA blot analyses. Quantitative real-time RT PCR revealed that the expression of BrSSR in transgenic tobacco plants increased by approximately 3.8-fold. Similar results were obtained by RNA blot analysis. Phenotypic characteristics analysis showed that transgenic tobacco plants with over-expressed BrSSR were more salt-tolerant than the wild type control under 250 mM NaCl for 5 days. Based on these results, we hypothesized that the over-expression of BrSSR may be closely related to the enhancement of salt tolerance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.909-916
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• 2013

Concrete containing lightly burnt MgO has long term expansibility. It also could compensate for the thermal shrinkage of mass concrete, because the hydration of MgO proceeds at a slow pace to long-term age. Thus, lightly burnt MgO has been applied to the construction of mass concrete such as dams. Recently, the expansion characteristics of MgO concrete with fly ash that could be applied to mass concrete for the reduction of hydration heat have been studied and however, limited studies on its durability. This study investigates the long-term durability characteristics of fly ash concrete with lightly burnt MgO. The durability tests on carbonation, freezing-thawing, diffusion of chloride, and resistance to sulfate attack were carried out for MgO concrete with curing for 360 days in submerged condition with different temperature of 20 and $50^{\circ}C$. The results reveal that MgO concrete shows a greater resistance of carbonation, diffusion of chloride, and resistance to sulfate attack. On the other hand the resistance of freezing-thawing was little influenced by MgO powder.