• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.970-979
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• 2006

Construction of underground structure requires higher standard of planning and design specifications than in surface construction. However, high construction cost and difficult working environment limit design level and construction quality. One of the most sensitive factors to be considered are infiltration and external pore-water pressures. Development of pore-water pressure may accelerate leakage and cause deterioration of the lining. In this paper, the development of pore-water pressure and its potential effect on the linings are investigated using physical model tests. A simple physical equipment model with well-defined hydraulic boundary conditions was devised. The deterioration procedure was simulated by controlling both the permeability of filters and flowrate. Development of pore-water pressure was monitored on the lining using pore pressure measurement cells. Test results identified the mechanim of pore-water pressure development on the tunnel lining which is the effect of deterioration of drainage system. The laboratory tests were simulated using coupled numerical method, and shown that the deterioration mechanism can be reproduced using coupled numerical modelling method.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1412-1419
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• 2005

Preventing the infiltration of rainwater into the landfill site is the main purpose of the final cover in landfill sites. Compacted clay layer or geomembrain have been used as a conventional landfill final cover. But they have several disadvantages when damages might occur due to puncturing, differential settlement and desiccation or freeze and thaw. For this reason, as an alternative method SRSL(Self Recovering Sustainable Liner) has been developed. Adopting the precipitation reaction of two chemical material, by forming precipitates that fill the pores, and lower the overall permeability of the liner. The advantage of this method is that when fracture of the liner occurs the remaining reactants of the two layers form precipitates that fill the fracture and recover the low permeability of the liner. In this study, the recovering ability of the SRSL with a crack due to the seasonal variation or differential settlements was investigated by permeability tests. And in order to estimate the durability of the SRSL after freeze/thaw and desiccation, uniaxial compression strength tests were performed.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.88-94
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• 2003

In recent, as Republic of Korea has been interested in environmental problem increasingly and became a member of many organizations or institutions related to environmental preservation such as a Ramsar convention, fundamental and completed methods to prevent ground water's drying up and leakage in tunnel excavation are requested. In this paper, we have studied the anticipated problems by tunnel excavation under the wetland and described the effective designed method to maintain the wetland's ecosystem environment. To accomplish this purpose, firstly, we investigated the wetland's ecosystem, ground's hydraulic properties and analysed the foreign similar case for tunnel excavation near the wetland. And by numerical analysis, we analyzed the runoff and infiltration quantity of water and hydraulic behaviour properties by saturation and unsaturation concept in rock mass and wetland. Finally, we established the effective countermeasure to minimize the ecosystem's bad influence by tunnel excavation.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.42.2-42.2
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• 2010

Recently, highly porous bone substitutes, which have interconnected open pore structure, have been focused on improving their mechanical properties and modifying their functions. Especially, it is highly required to develop functional gradient structured bone substitute which is available for controlling their material properties such as bioresorption rate and elastic modulus. Porous $ZrO_2$ scaffold was fabricated by the sponge replica method using PU sponge. After 3 times of dip coating and the subsequent oven drying, burning out and microwave sintering were carried out. Various $ZrO_2$-BCP powder mixtures were prepared depending on the ratio and coated on the $ZrO_2$ scaffold by dip coating process. X-ray diffraction analysis was performed to characterize the phase identification of the scaffolds. Microstructures of the bone substitutes were observed using scanning electron microscopy.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.19-30
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• 1982

This study was performed to elucidate the histopathologic distribution of immunoglobulins, particularly IgA, IgG and IgM in the periapical lesions, including 22 periapical granulomas and 18 periapical cysts. The immunoperoxidase staining method using reagents manufactured and supplied by Danish DAKO company was employed in this study. In comparison with the immunohistochemical methods, this method was proved to be reliable and convinient one to detect immunoglobulins in the tissue. The following results were obtained: 1. In the 22 periapical granulomas, IgG was found in 20 cases (90.9%), IgA in 16 cases (72.7%) and IgM in 19 cases (86.3%). 2. In the 18 periapical cysts, IgG was found in 16 cases (88.8%), IgA in 13 cases (72.2%) and IgM in 15 cases (83.3%). 3. The distribution of immunoglobulins both in periapical granulomas and periapical cysts was in great diversity according to the lesion and area. 4. More immunoglobulins were found in the exudative area with moderate or severe infiltrations of plasma cells and lymphocytes and less concentration of immunoglobulins were seen in the area with leukocytes infiltration and tissue destruction. 5. The area with collagenolysis and reparative activity contained more abundant IgG and IgM than IgA in periapical granulomas. 6. IgG was dominant in the granulomatous connective tissue and immunoglobulins were not easily found in the fibrous capsule in periapical cysts.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.2
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• pp.95-98
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• 2015

PURPOSE: This study was conducted to devise a method of preventing water infiltration into the surface electrodes during EMG measurements underwater and on the ground and to check the reliability of Electromyography (EMG) measurements when underwater. METHODS: Six healthy adults were selected as subjects in this study. The measurements in this study were conducted in pool dedicated to underwater exercise and physical therapy room in the hospital building. An MP150 (Biopac Systems, US, 2010) and a BioNomadix 2-channel wireless EMG transmitter (Biopac Systems, US, 2012) was used to examine the muscle activity of rectus femoris, biceps femoris, tibialis anterior, gastrocnemius of dominant side. The subjects repeated circulation tasks on the ground for more than 10 min for enough surface electrode attachment movement. After a 15-min break, subjects performed the circulation task underwater(water depth 1.1m, water temperature $33.5^{\circ}C$, air temperature $27^{\circ}C$), as on the ground, for more than 10 min, and the MVIC of each muscle was measured again. SPSS v20.0 was used for all statistical computations. RESULTS: The maximum voluntary isometric contraction (MVIC) values between the underwater and on the ground measurements showed no significant differences in all four muscles and showed a high intraclass correlation coefficient (ICC) of >0.80. CONCLUSION: We determined that EMG measurements obtained underwater could be used with high reliability, comparable to ground measurements.

• Membrane and Water Treatment
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• v.10 no.1
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• pp.19-28
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• 2019

To minimize the impact of urbanization, accurate performance evaluation of Low Impact Development (LID) facilities is needed. In Korea, the method designed to evaluate large-scale non-point pollution reduction facilities is being applied to LID facilities. However, it has been pointed out that this method is not suitable for evaluating the performance of relatively small-scale installed LID facilities. In this study, a new design formula was proposed based on the ratio of LID facility area and contributing drainage area, for estimating the Stormwater Interception Ratio (SIR) for LID facilities. The SIR was estimated for bio-retentions, infiltration trenches and vegetative swales, which are typical LID facilities, under various conditions through long-term stormwater simulation using the LID module of EPA SWMM. Based on the results of these numerical experiments, the new SIR formula for each LID facility was derived. The sensitivity of the proposed SIR formula to local rainfall properties and design variables is analysed. In addition, the SIR formula was compared with the existing design formula, the Rainfall Interception Ratio (RIR).

• BMB Reports
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• v.55 no.7
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• pp.342-347
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• 2022

Defense priming allows plants to enhance their immune responses to subsequent pathogen challenges. Recent reports suggested that acquired resistances in parental generation can be inherited into descendants. Although epigenetic mechanisms are plausible tools enabling the transmission of information or phenotypic traits induced by environmental cues across generations, the mechanism for the transgenerational inheritance of defense priming in plants has yet to be elucidated. With the initial aim to elucidate an epigenetic mechanism for the defense priming in plants, we reassessed the transgenerational inheritance of plant defense, however, could not observe any evidence supporting it. By using the same dipping method with previous reports, Arabidopsis was exposed repeatedly to Pseudomonas syringae pv tomato DC3000 (Pst DC3000) during vegetative or reproductive stages. Irrespective of the developmental stages of parental plants that received pathogen infection, the descendants did not exhibit primed resistance phenotypes, defense marker gene (PR1) expression, or elevated histone acetylation within PR1 chromatin. In assays using the pressure-infiltration method for infection, we obtained the same results as above. Thus, our results suggest that the previous observations on the transgenerational inheritance of defense priming in plants should be more extensively and carefully reassessed.

• Journal of the Korean Geotechnical Society
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• v.24 no.9
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• pp.5-11
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• 2008

Seepage induced earthern slope failures occurs in concert with meteorological events when large quantities of groundwater are channeled into slopes through infiltration. The presence of flowing groundwater in earthern slopes can induce ground failures that result in significant property damage and potential loss of life. Seepage induced earthen slope failures represent a serious problem in geotechnical engineering. This research applies existing fluid-solid numerical modeling capabilities to the study and prediction of seepage induced earthen slope failures. Study of the targeted application holds potential for much needed advances in geotechnical engineering analysis technology which could be used to design more effective engineering slope stabilization interventions.

• ALGAE
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• v.21 no.4
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• pp.479-483
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• 2006

In preparation of the biological samples for electron microscopy, the chemical fixation by glutaraldehyde, paraformaldehyde, and OsO4 has been generally used for a long time. However, the chemical fixation method has some problems: the infiltration time is a little bit long and the ultrastructure of cell or tissue transforms before complete fixation of sample. So, recently, cryo-fixation is considered more often in biomedical field. In this study, we compared High Pressure Freezing (HPF) method with chemical fixation method using a algal sample (Ptilota filicina J. Agardh), which was difficult to fix using chemical fixation method. In chloroplast, the ultrastructure of thylakoid lamella and phycobilisome can not show clearly by chemical fixation. In this study we could observe the ultrastructure of thylakoid lamella and phycobilisome of chloroplast very clearly using HPF fixation. An improved images of ultrastructures of nucleus, mitochondrion and floridean starch could obtain. These results suggest that HPF method is very useful method in algal specimen for electron microscopy.