• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.239-244
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• 2001

Natural clayey soils or improved grounds are in a overconsolidated conditions due to changes in vertical stress and pore pressures, desiccation, ageing and so on. These grounds show inelastic stress-strain behaviour characteristics within all range of strain except very small strain (${\gamma}$$\_$s/$\leq$10￣$^3$∼10￣$^4$%) when construction, such as excavations and retaining walls, is performed. Also it strongly depends on loading rate of current stress path and recent stress path. This study carried out drained stress path tests by varying loading rate of current and recent stress path. Test results indicated that stress-strain behaviour of overconsolidated clay depends on loading rate, especially loading rate of current stress path.

• KIEAE Journal
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• v.7 no.3
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• pp.21-30
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• 2007

This research focuses primarily on the feasibility of applying bryophyte to man-made structures in modern urban environment. The study is based both on the role of bryophyte known in the process of the naturalization that life has come on the land and the physiological and ecological characteristics of bryophyte. The primary characteristics of this species lie in its desiccation-tolerance and poikilohydry that supports its enduring survival even under the desperate environmental conditions. The monitoring of applying bryophyte to man-made structures has shown us that bryophyte could control microclimate conditions, help to mitigate flood by reducing runoff, and lessen thermal conductivity, etc. The application of bryophyte to man-made structures has just started since 2002. Even though efforts to use bryophyte in greening man-made structures in Japan and Korea have resulted in both successes and failures, it is noticeable that there has been quite much technical progress in using this unique plant species.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.189-195
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• 1998

콘크리트 구조물이 초기재령에서 외기에 노출될 때, 수부확산으로 인하여 수분의 이동이 일어나고, 또한 자체건조도 발생한다. 이러한 콘크리트 내부의 수분확산과 자체건조에 의하여 콘크리트의 위치에 따라 상대습도가 변호한다. 특히 고강도 콘크리트의 경우에 단위 시멘트량을 많이 사용하기 때문에 , 초기재령에서 콘크리트 단면의 수분분포는 자체건조에 의하여 큰 영향을 받는다. 본 연구에서는 초기재령에서 외기에 노출된 콘크리트 내부의 여러 위치에서 상대습도를 측정하였다. 또한 자체건조로 인한 콘크리트의 상대습도 변화를 측정하여 초기재령에서 수분확산과 자체건조가 콘크리트 내부의 각 위치에서 상대습도에 미치는 영향을 검코하였다. 그리고 수분확산 이론에 의하여 해석결과와 실험결과를 비교하여 \ulcorner재령에서 수분확산 이론의 타당성을 검증하였다. 저강도 콘크리트 단면의 수분분포는 주로 수분확산에 의하여 영향을 받았으며, 자체건조의 영향은 매우 작게 나타났다. 그렇지만 고강도 콘크리트는 수분확산 뿐만 아니라 자체건조에 의하여도 영향을 받았다. 또한 수분확산 이론에 의한 해석결과는 실험결과를 잘 예측하였다.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.197-204
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• 1998

초기재령에서 외기에 노출된 콘크리트는 수분확산으로 인하여 부등건조수축이 발생하고, 또한 자체건조로 인하여 자기수축도 발생한다. 따라서 콘크리트 재부의 수축변형도는 이러한 자기수축을 포함하고 있으므로 이를 고려해야 한다. 본 연구에서는 초기재령에서 콘크리트 강도에 따라 자기수축의 영향을 고려하여 부둥건조수축에 대한 실험과 해석을 수행하였다. 또한 콘크리트 내부의 부등수분분포로 인한 수축변형도에 대하여 실험결과와 해석결과를 비교하여, 해석방법의 타당성을 검증하였다. 실험 및 분석결과에 의하면 저강도콘크리트는 수분확산으로 인하여 주로 수축현상이 일어나고 자기수축의 영향은 거의없었다. 그렇지만 고강도 콘크리트는 자기수축에 의해서도 영향을 받았다. 그리고 콘크리트의 부등건조수축은 강도에 따라 큰 차이를 나타냈다. 또한 제시한 해석방법에 의한 해석결과는 실험결과를 잘 예측하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.569-576
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• 2002

Recently, the hydraulic fill method is commonly used in many reclamation projects due to lack of fill materials. The method of hydraulic fill in reclamation is executed by transporting the mixture of water-soil particles into a reclaimed land through dredging pipes, then the dredged soil particles settle down in the water or flow over an out flow weir with the water. In the present study, to compare the soil and sand-mat mixed method with sand-air jet method for shallow improvement of hydraulic fills at southern seashore, the model tests were performed. Through the model test results, the behavior of surface as disturbance of desiccation crust is analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.683-686
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• 2004

In recent years, some attention was particularly given to cracking sensitivity of high performance concrete. It has been argued and demonstrated experimentally that such concrete undergoes autogenous shrinkage due to self-desiccation at early age, and, as a result, internal tensile stress may develop, leading to micro cracking and macro cracking. One possible method to reduce cracking due to autogenous shrinkage is the addition of expansive additive. Tests conducted by many researches have shown the beneficial effects of addition of expansive additive for reducing the risk of shrinkage-introduced cracking. However, the research on hydration model of expansion additive has been hardly researched up to now. This paper presents a study of the hydration model of Ettringite-Gypsum type expansive additive. Result of comparing forecast values with experiment value, proposed model is shown to expressible of hydration of expansive additive.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.553-556
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• 2006

Chloride penetration is the main reason which causes the deterioration of concrete structures. Chloride penetration of concrete structures due to chemical-physical phenomena can be profitably analyzed by means of model-based simulations. The main purpose of this paper is to analyze chloride penetration considering self-desiccation, convection and admixture(GBFS: granulated blast-furnace slag) effects. Basic governing equations are modified properly to apply these effects to chloride penetration analysis. Temperature and relative humidity data of In-Cheon from Korea Meteorological Administration are used for analyzing chloride penetration.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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• pp.1336-1342
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• 2012

In Burkholderia pseudomallei, the pathogen that causes melioidosis, the gene cluster encoding the capsular polysaccharide, is located on chromosome 1. Among the 19 capsular genes in this cluster, wzm has not been thoroughly studied. To study the function of wzm, we generated a deletion mutant and compared it with the wild-type strain. The mutant produced less biofilm in minimal media and was more sensitive to desiccation and oxidative stress compared with the wild-type strain, indicating that wzm is involved in biofilm formation and membrane integrity. Scanning electron microscopy showed that the bacterial cells of the mutant strain have more defined surfaces with indentations, whereas cells of the wild-type strain do not.

• Journal of Wetlands Research
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• v.4 no.2
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• pp.13-22
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• 2002

Difference of the inset diversity and community structures between the bog Hwaeom-neup and its surrounding forest of Mt. Wonhyo-san located at Yangsan were investigated. Overall 15 orders, 87 families, 204 genera and 233 species were identified. Hydrophilic Harpalidae species were observed in small number at the bog, while the insect species representing hardwood forest were also collected at the bog. Species diversity was relatively higher at the forest (H'=4.80) than at the bog (H'=4.10). The dominant species was Diplous depressus (Gebler) both at bog as well as at forest. Ground-walking Coleoptera as Carabus sternbergi stembergi Roeschke, Damaster jankowskii jankowskii (Oberthur) and D. depressus was spread from forest into bog. Longhorn beetles Leptura arcuata Panzer and Chlorophorus diadema (Motschulsky) being characteristic species of shrub forest were also observed spreading into bog. It was consequently suggested that the bog was in part progressed into dry succession and its boundary was not clearly defined with forest at least upon the structure of insect commnunity.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.289-295
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• 2010

The bacterium Deinococcus radiodurans is one of the most resistant organisms to the effects of ionizing radiation and other DNA-damaging agents. In this study, distributions of 10 ddr (DNA damage response) genes were investigated in 8 species of Deinococcus by polymerase chain reaction (PCR). We have compared the sequences of ddr genes of D. radiodurans, D. geothermalis and D. deserti, and selected primers which are suitable for the detection of ddr in different species of Deinococcus. A sequence homology search and PCR assay showed that ddrO, which encodes a global regulator of the radiation-desiccation response, was most well conserved in the Deinococcus lineage.