• Journal of the Korean Geosynthetics Society
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• v.5 no.4
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• pp.49-58
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• 2006

Recently, geosynthetic clay liners (GCLs) have increasingly been used to replace compacted clay liners (CCLs) in composite liner systems. Since the introduction of GCLs to waste containment facilities, one of the major concerns about their use has been the hydraulic equivalency to CCLs as required by regulations. Laboratory test results and more recently field observations show that the thickness, or mass per unit area, of hydrated bentonite in a GCL can decrease under normal stress, especially around zones of stress concentration or nonuniform stresses, such as a rock or roughness in the subgrade, a leachate sump, or wrinkles in an overlying geomembrane. This paper presents field case histories that confirm the laboratory observations of bentonite migration and the effect of bentonite migration on hydraulic equivalency and contaminant transport through a GCL.

• Journal of Soil and Groundwater Environment
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• v.7 no.1
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• pp.33-40
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• 2002

The study was performed to evaluate the effect of landfill leachate on the hydraulic conductivity of Geosynthetic Clay Liner (GCL) with two types of leachate. GCL used in waste landfills have a significant ability as a barrier material, however, they also have a potential danger when exposed to some organic and inorganic leachate as well as humic materials. In this study, swelling tests and hydraulic conductivity tests were performed to evaluate the effect of humic materials and landfill leachate on the hydraulic characteristics of the GCL. The result of swelling tests showed that the amount of humic materials and high electronic conductivity caused a decrease of the swelling of bentonite. This is expected to increase the hydraulic conductivity of GCL. The increasing of hydraulic conductivity observed for GCL permeated with 0-leachate was significantly higher than that of Y-leachate. This result shows that humic materials are obviously affecting with the increasing of hydraulic conductivity of GCL.

• Korean Journal of Plant Resources
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• v.36 no.3
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• pp.225-236
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• 2023

Stomatal traits such as stomata density (SD), aperture length (APL) and width (APW), guard cell length (GCL) and width (GCW), and distance between stomata (DIS) were investigated to identify correlation with agronomic traits for 35 Korean wheat cultivars. Flag leaf width (FLW) of Korean wheat cultivars was the widest in Ol-mil, and the narrowest in Keumkang. SD tended to be higher on the adaxial side than on the abaxial side in Korean wheat cultivars. SD of adaxial and abaxial sides was classified into a cultivar with a significantly different or not. In APL, 18 wheat cultivars showed significant differences according to leaf side, and APL of adaxial was longer than APL of abaxial in 13 wheat cultivars. In APW, 15 wheat cultivars showed a significant difference, and APW of abaxial was wider than APW of adaxial among them. In GCL, 14 wheat cultivars showed a significant difference, and the GCL of abaxial was longer than the GCL of adaxial in 10 wheat cultivars. In GCW, 10 wheat cultivars showed a significant difference, GCW of adaxial was wider than GCW of abaxial and in 6 wheat cultivars. FLW of adaxial and abaxial showed a negative correlation with GCL and a positive correlation with grain number per panicle. FLW of only abaxial showed a positive correlation with DIS. The SD of the adaxial showed a negative correlation with GCL, while the SD of the abaxial showed a negative correlation with APL. APL of both sides of the leaf showed a positive correlation with GCL, and APW of only abaxial showed a negative correlation with GLC. DIS of adaxial showed a negative correlation with tiller number (TN), while DIS of abaxial showed a positive correlation with GNP.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.352-355
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• 1998

토목섬유제품 중에서 차수재조 널리 사용되는 지오멤브레인은 1$\times$$10^{-12}$의 낮은 투수계수를 갖고 있지만 시공전후 찢어지거나 구멍이 뚫리게 되면 침출수의 유출이 발생하여 환경오염을 일으키게 된다. 이를 보완하기 위해 친수성과 팽윤성이 큰 벤토나이트 물질을 이용한 Geosynthetic Clay Liner(GCL) 복합재료가 개발되었다. GCL은 지오텍스타일이나 지오멤브레인사이에 벤토나이트를 충진시키고, 접착제 또는 니들펀칭(needle-punching)이나 스티칭(stitching)과 같은 기계적인 방법으로 결합한 복합재료이다. (중략)

• Toxicological Research
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• v.22 no.1
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• pp.39-45
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• 2006

As the antioxidant and free radical scavenger, glutathione (GSH) participates in the preservation of cellular redox status and defense against reactive oxygen species and xenobiotics. Glutamate-cysteine ligase (GCL; also known as ${\gamma}$-glutamylcysteine synthetase, EC 6.3.2.2) is the rate limiting enzyme in GSH synthesis. In the present study, the accurate method for determination of GCL activity in crude liver extracts was developed by measuring both ${\gamma}$-glutamylcysteine and GSH from cysteine in the presence of glutamate, glycine and an ATP-generating system. We added glycine to promote the conversion of ${\gamma}$-glutamylcysteine to GSH, and to minimize the possibility of ${\gamma}$-glutamylcysteine metabolism to cysteine and oxoproline by ${\gamma}$-glutamylcyclotransferase. We established optimal conditions and substrate concentrations for the enzyme assay, and verified that inhibition of GCL by GSH did not interfere with this assay. Therefore, this assay of hepatic GCL under optimal conditions could provide a more accurate measurement of this enzyme activity in the crude liver extracts.

• Journal of the Korean Geosynthetics Society
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• v.3 no.2
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• pp.23-29
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• 2004

One of the most important concern in the design of barrier layer in to protect the water through the landfill. The barrier layer consists of a single compacted clay liner(CCL) or a composite liner with high density polyethylene(HDPE). The construction of barrier layer at the edge of cover system usually has some problems because of steep slope in the landfill. In this study the authors evaluate the geosynthetic clay liner(GCL) as a barrier layer at the edge of the final cover system in landfill. The GCLs were simulated the stability of slope, the HELP(Hydrologic Evaluation of Landfill Performance) and the durability of environmental situation. As the results, the GCL has more stable than the CCL. Therefore, the authors suggest that the GCL in good for the barrier layer of the final cover system in the landfill.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.137-146
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• 2002

Geomembrane, compacted clay liner, and geosynthetic clay liner (GCL) are widely used to prevent leachate from leaking to adjacent geo-environment at a municipal solid waste (MSW) landfill. Interface shear strength between GCL and geomembrane installed at a landfill side slope is important properties for the safe design of side liner or final cover systems. The interface shear strength between two geosynthetics was estimated by a large direct shear test in this study. The shear strength was evaluated by the Mohr-Coulomb failure criterion. The effects of normal stress, hydration or dry condition, and a hydration method were investigated. The test results show that the interface shear strength and shear behavior varied depending up on the level of normal stress, the type of geosynthetic combinations, and a hydration method. When GCLs were sheared after being hydrated under 6kPa loading, the results were consistent with those published by other researchers. Summaries of friction angles, normal stress and hydration condition is presented. These friction angles could be used as a reference value at a site where similar geosynthetics are installed.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.634-639
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• 2013

The use of medical imaging has been increased for diagnosis of cancer or vessel disease. Among the medical imaging, computed tomography (CT) is one of the popular methods, however, which should need administration of contrast medium. Therefore, we developed gold coated liposomes (GCL) as a contrast medium. To coat gold on the liposomal surface, positive charged liposomes was prepared and then negative $Au^-$ can coat on the liposomal surface by electronic interaction. The size of GCL was $154.8{\pm}9.2$ nm and surface charge was $27{\pm}3.2$ mV, respectively. The morphology of GCL was confirmed by electron microscopy (SEM) and transmission electron microscopy (TEM). The coating efficiency of gold was 18%. Chemical procedure for gold coating on liposomal surface was not toxic for cell cytotoxicity by MTT assay. Finally, we demonstrated attractive CT image for GCL. Taken together, the GCL would be useful for various vessel related disease as a contrast medium.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1006-1010
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• 2010

Pseudomonas putida JM37 metabolized glyoxylate at a specific rate of 55 g/g dry biomass/day. In order to investigate their role, three genes encoding enzymes that are potentially involved in the conversion of glyoxylate were disrupted; namely, tartronate semialdehyde synthase (gcl), malate synthase (glcB), and isocitrate lyase (aceA). Strains with transposon insertion in either of these genes were isolated from a 50,000 clone library employing a PCR-guided enrichment strategy. In addition, all three double mutants were constructed via targeted insertion of a knock-out plasmid. Neither mutation of gcl, glcB, and aceA nor any of the respective double mutations influenced glyoxylic acid conversion, indicating that P. putida JM37 may possess other enzymes and pathways for glyoxylate metabolism.

• Journal of the Korean Geosynthetics Society
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• v.7 no.2
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• pp.49-52
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• 2008

Most of waste sludge has generally been disposed in landfill site or dumped in the ocean, which will be banned by the content of its heavy metals according to London Dumping Convention in Korea. Therefore, environmentally friend methods are urgently required for the treatment and disposal of the sewage sludge. Thermal hydrolysis is one of the good treatment methods to solve the sludge problems. In this study, the physical and environmental testing was conducted to evaluate the feasibility of by-product cake from the thermal hydrolysis as liner or cover materials in landfill.