• The Journal of the Petrological Society of Korea
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• v.19 no.1
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• pp.19-30
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• 2010

The Jurassic Daebo Ogcheon granite is distributed in the Ogcheon area which is located in the central part of the Ogcheon Belt, Korea. This paper newly examines the timing of Honam shearing on the basis of the petrofabric researches on the deformation structures of the Ogcheon granite. The structural shape of Ogcheon granite is mainly characterized by a wedge shaped of E-W trend and an elongate shape of ENE trend in geological map and by contacts parallel to the regional S1 foliation in the host Ogcheon supergroup. It indicates that the pluton was permittedly emplaced after the S1 formation. The main deformation structures are marked by a solid-state tectonic foliation of N-S trend, which passes through the contact of the pluton, and by an aplitic dyke of E-W trend, and by sinistral, NW and E-W oriented shear zones on the eastern border of the pluton. The petrofabric study on the main deformation structures suggests that the tectonic foliation and the aplitic dyke were formed by the Honam dextral strike-slip shearing of (N)NE trend at ca. $500{\sim}450^{\circ}C$ deformation temperature, and that the sinistral shear zones could be induced by the dextral rotation of the pluton from its original site of intrusion, that is, by the shear strain which is due to sliding of the pluton past the host rocks. The history of emplacement and deformation of the Ogcheon granite and the previous results on the timing of Honam shearing would be newly established and reviewed as follows. (1) Early~Middle Jurassic(187~170 Ma); intrusion of syntectonic foliated granite related to Early Honam shearing, (2) Middle Jurassic(175~166 Ma); main magmatic period of Jurassic granitoids, the permitted emplacement of the Ogcheon granite, (3) Middle~Late Jurassic(168~152 Ma); main cooling period of Jurassic granitoids, the deformation of the Ogcheon granite related to Late Honam shearing. Thus, this study proposes that the Honam shear movement would occur two times at least during 187~152 Ma (ca. 35 Ma) through the intertectonic phase of 175~166 Ma.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.439-446
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• 2021

This study was to investigate whether there are differences in subjective bad breath-related characteristics and psychological characteristics of sports masks printed with natural minerals compared with quarantine masks and cotton masks. The study subjects were divided into 30 people in the Sports Mask Group, 30 people in the KF Mask Group (KMG), and 30 people in the cotton mask group (CMG), and a total of 90 subjects participated in the study. It was randomly sent to use 1 mask per day and 3 masks for 3 days. The study period was conducted from October 15, 2020 to October 30, 2020. As a result of the study, there was no difference in the use of masks between the three groups in terms of bad breath health and dry mouth. However, the sports mask was superior to other masks in oral respiration and bad breath angle. As a result of analyzing psychological factors, there was no difference between the 3 groups for depression. However, in the stress factor, sports masks were superior to other masks in stress. The results of this study are valuable as suggesting the direction of use of functional masks, and we hope that they will be used as basic data for functional mask research to be studied in the future.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.121-131
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• 2006

This study is performed to examine the ground reinforcement effect and the environmental impact of LW injection, which is widely used during the excavation of high-rise apartment buildings. In addition, it proved that by conducting field exploration and laboratory test the engineering ground reinforcement effect of LW injection in the ground has low coefficient of permeability. The environmentally friendly aspect was evaluated through an assessment of environmental impact. The results of laboratory test shows that LW coagulating material with SC type soil structure has significant improvement of uniaxial compressive strength, increasing by three times and the shear strength increasing by twice, coefficient of permeability decreasing six to seven times. And the result of environmental impact tests show that from 6 hour after where the pH increases until 7.96 to initially it diminished, it started and to 80 hour after it recovered a pH 7.25 initially with 7.30. The chemical composition analysis test result that unpolluted water and polluted water hydrogen ion concentration (pH) show that the unpolluted water pH 7.36, polluted water pH 7.85, which is inside the Ministry of Environment standard of drinking water (the pH 5.8~8.5). The assessment of environmental impact and chemical analysis test also demonstrate that the LW coagulating material is environmentally friendly. In the $Cr^{6+}$ and the salinity detection test, it was proven that the salinity is slight and the $Cr^{6+}$ is not detected.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.90-96
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• 2009

The high rising building construction makes increasing the requirement of high strength concrete. Especially, the workability analysis is related with dispersion of admixture such as SF for improving strength and FA, BS for reducing construction cost and improving durability of Ultra High Strength Concrete which has over 100 MPa of compressive strength is very important. Precisely, decreases dispersion because of lumping situation of each admixture and it causes the workability of admixture is decreased. Therefore, the workability of cement paste is tested for analyze effects of pre-mixed cement for solving those problems with it to this research. The summary of the results are like below. First of all, OBS is increasing workability more than OFS. This result causes that the glassy surface of BS in the OBS is increasing workability and the absorption of admixture of FA in the OFS is decreasing workability. In the case of mixing methods, pre-mixing method is increasing workability more than normal one. This result shows that the normal mixing method is bad dispersion of binders. The other side, the pre-mixing method is good. Furthermore, depending on the mixing time, according to the increasing mixing time such as 30, 60, and 120 seconds, the dispersion of binders and workability turns better.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.833-841
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• 2021

This study was an entertainer who was in charge of female music in the Joseon Dynasty, but the existence of gisaengs, who were recognized as'sexual partners' of the four grandfathers, and the Joseon Dynasty, when their existence was possible. I tried to reveal the social characteristics of Therefore, the research is meaningful in that it attempted to reveal the relationship between the grandfather and the gisaeng from various perspectives, and that it is possible to confirm the various social roles of the gisaeng. In the Confucian society, female musicians were not allowed to participate in Naeyeon and Chinjamrye, where women were the main pillars, so not only could the girl's music survive until the end of the Joseon Dynasty, but it was enough to reveal the existence of a professional artist. The existence of gisaengs is not irrelevant to the social background of the Joseon Dynasty, and therefore, it is impossible to define the Joseon Dynasty with the holy morality of modern society. It is believed that 『catching green onions is expected to enhance the aspect of a gisaeng as a celebrity, based on the interpretation that it is viewed from the perspective of an entertainer possessing an extraordinary and noble spirit rather than portraying the gisaeng in an erotic standard.

• The Journal of Engineering Geology
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• v.24 no.2
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• pp.201-215
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• 2014

This study was performed to investigate the correlation between hydraulic conductivity and the flow rate of an aquifer, with the flow rate calculated from the laterals of the radial collector well using data obtained by the development project of riverbank filtration (Second Phase) in Changwon City. The hydraulic conductivity was empirically calculated from unconsolidated sediments collected from a sandy gravel layer along the middle-to-downstream sections of the Nakdong River. The Beyer equation produced the most suitable hydraulic conductivity from the various empirical formulas employed. The calculated hydraulic conductivity ranged from 0.083 to 0.264 cm/s, with an average value of 0.159 cm/s, suggesting that the aquifer in the study area possesses a high permeability with a good distribution of sandy gravel. The relationship between the calculated hydraulic conductivity in the aquifer and the entrance velocity into the screen, the flow rate was analyzed through the linear regression analysis. From the result of regression analysis, it showed that the hydraulic conductivity and the entrance velocity into the screen and the flow rate have a linear regression equation having about 72% of the high correlation. The result of verification in the measured data between each variable showed a high suitability from being consistent with the approximately 72% in the linear regression analysis. This study demonstrates that the groundwater flow rate can be estimated within the laterals of the radial collector well using a linear regression equation, if the hydraulic conductivity of the aquifer is known. This methodology could thus be applicable to other aquifers with hydraulic conductivity and permeability parameters similar to those in the present study area.

• Asian Journal of Turfgrass Science
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• v.26 no.2
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• pp.129-134
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• 2012

Research was focused on the improvement of poor drainage problems on golf course fairway which had not been performed soil test or properly amended during the course construction. The analysis of the drainage problem basically was caused by a deterioration of soil physical properties by the top layer compaction. The soil hardness reached about 3,000 Kpa around 5~6 cm of soil profile. The slow infiltration speed to subsoil by the compaction was caused directly a poor drainage capacity. However, the properly amended sand soil showed an apparent value of 1,500 Kpa through the subsoil. The water content test showed a similar result that higher rate of 20~30% and ideal rate of 8~12% at poor drainage area and successfully amended area, respectively. However, an imported topsoil media which had higher content of silt and clay from a trans-planted sod had made a heterogeneous soil profile and that caused a poor drain capacity by a low infiltration rate. Those drainage problems triggered to buildup a reduced soil layer by poor soil gas exchange. The soil environment of deoxidation enhanced anaerobic microbial population and induced methane gas build-up to 55 ppm, and that resulted an adverse effect on turf growth by root growth retardation, consequently.

• Geotechnical Engineering
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• v.14 no.6
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• pp.113-125
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• 1998

At the end of 1997 about 3 million tons of coal ash was produced as byproducts from the coal fired electrical power plants in Korea. Only about 27% of that byproducts was utilized as the admixtures of cement and concrete industry. But the large quantity of coal fired fly-ash has been used as the soil improvement materials in other countries. So the aim of this study is the estimation of the applicability of the coal fired fly-ash as microfine grouting materials by admixing the superfine particles which were separated from the coal fired fly-ash for the higher values. The 6 types of specimens were manufactured in the laboratory for the purpose of estimating the chemical and physical properties of cement and grouts. These specimens consisted of 2 specific surfaces of 6, 000 and 8, 000$cm^2$/g in Elaine method. And these specimens are devide into 3 ratios (30%, 50%, 70%) of fly-ash by weight. From the estimated properties of the coal fired fly-ash microflne cements and grouts, 50% fly-ash is the most suitable ratio for grouting materials. However, further study of durability is necessary for using fly-ash grouts practically at the field projects. The higher content of the unburned carbon of fly-ash increases the thinner layer of carbon on the surface of solution of grouts, and requires more quantity of surface active agent. As a results of this study, it is found that the microfine fly-ash is very useful as a good grouting material if 50% of fly-ash is added with the microfine portland cement. So, in the near future, if the coal fired fly-ash is able to be used as grouting material in Korea, the demand of fly-ash will increase rapidly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5906-5914
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• 2013

Recently in Korea, the policy is being proceeded to build a intergenerational housing on artificial ground of railroad site for utilizing rental house. Due to narrow space of rail road site, suitable method have to be developed such as micropiles which is known as a method of a fast construction. However, If micropile is used as foundations for the super structure, construction cost is increases compared with other pile. Consequently, new concept micropile proposed to improve both bearing capacity and cost efficiency of general micropile. New concept micropile consists of waveform cement grout surrounding tread bar that formed by grouting the soil layer with jet grouting method as control the grout pressure and flow. The micropile with waveform is expected to decrease the construction cost by cut down pile length of general micropile. This paper examined the behavior of the new concept micropile with waveform subjected to axial load using two-dimensional axisymmetric numerical analyses method. According to the numerical result, there will cost effectiveness as the pile displacement decreased despite the length of waveform micropile is down about 5% from a general micropile under the same loading condition. Also, the effect of skin friction force which mobilized from the waveform of micropile appeared at relatively soft ground.

• Economic and Environmental Geology
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• v.43 no.4
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• pp.371-379
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• 2010

Fresh water injection test in a fractured bedrock aquifer was applied as an efficient approach to lower saline concentrations in the saltwater-freshwater transition zone formed by seawater intrusion in a coastal area. The methodology and effectiveness of fresh water injection for hydraulically controlling seawater intrusion is overwhelmingly site dependent, and there is an urgent need to characterize the permeable fractures or unconsolidated porous formations which can allow for seawater flow and transport. Considering aquifer characteristics, injection and monitoring boreholes were optimally designed and completed to inject fresh water through sand layer and fractured bedrock, respectively. We devised and used the injection system using double packer for easy field operation and maintenance. Overall fracture distribution was systematically identified from borehole image logs, and the section of fresh water injection was decided from injection test and monitoring. With fresh water injection, the fluid electrical conductivity of the monitoring well started to be lowered by the inflow of fresh water at the specific depth. And this inflow leaded to the replacement of the fluid in the upper parts of the borehole with fresh water. Furthermore, the injection effect lasted more than several months, which means that fresh water injection may contribute to the mitigation of seawater intrusion in a coastal area.