• Journal of the Korean earth science society
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• v.38 no.7
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• pp.570-580
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• 2017

The purpose of the study was to evaluate the groundwater quality of Sinan-gun, Jeollanam-do, an island located in the southern part of the Korean peninsula where the effect of seawater on the groundwater quality had not been investigated in the past. In order to evaluate its effect, the hydrogeological parameters including groundwater quality and major dissolved components were investigated. The water quality was measured four times in the field, and 74 of 163 samples that showed the high conductivity value of more than $500{\mu}S/cm$ and the influence of seawater on the groundwater were analyzed by $Cl^-/HCO_3{^-}$ molar ratio. The results showed that, 40 samples out of 74 were found to have a value of 2.8 or more, indicating severe and very severe effects. According to the type of groundwater quality, the ratio of samples belonging to Na-Cl type, which is considered to be influenced by the direct seawater, is 35.3% for bedrock groundwater and 52.5% for weathered zone and alluvial groundwater. In the evolution stage of groundwater due to seawater infiltration, the type of Ca-Cl prior to the Na-Cl type is 44.1% in bedrock groundwater and 45% in weathered zone and alluvial groundwater. The effect of sea water on the aquifer is likely to be influenced by distance from the shore, pumped water, and tide.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.103-111
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• 2013

In this study, field measurements were conducted in the section about 7 km from sea dike to westward. The observations of along channel current were carried out, and water temperature and salinity were measured simultaneously at 10 stations during one tidal cycle, and sampling interval is 1 hour. The maximum ebb current is about 1.5 m/s at the surface layer but flood current is 0.4 m/s at the bottom layer during discharge period. Residual current during river discharge shows two layer structures which is typical characteristic of the estuary system. On the other hand, residual current during a period with no discharge has shown multi-layer structure different from general estuarine systems. The distribution of high salinity can be seen at the bottom layer as the effect of discharge does not reach down to the bottom layer during discharge. As a result, freshwater is not effected at the bottom layer during observation, and mixing of surface layer to bottom layer is reduced by stratification.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.6
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• pp.710-717
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• 1996

To obtain the basic informations on the farm cultivation of Eleutherococcus senticosus Max., field survey of the native habitat in Mt. Deokyu such as weather, soils, vegetation and growth was carried out. The habitat of E. senticosus is situated at 127$^{\circ}$ 45'E, 35$^{\circ}$ 52' N in Mt. Deokyu where the elev-tion ranges from 1,050 to 1,300 meters above the sea level. Mean annual temperature forecasted around the habitat was 5.8$^{\circ}C$, mean maximum temperature in August, 24.6$^{\circ}C$ ; mean minimum temperature in January, -13.5$^{\circ}C$ and relative humidity during the growth periods, over 95%. To divide the area according to climatic conditions was classified cool temperature and humid rain forest zone. In another view, it belonged to deciduous broad-leaf forest zone and soil texture was sandy loam with dark brown gravels. Acidity and P$_2$O$_{5}$ content of soil represented pH 5.2～5.6 and 10ppm, respectively. The growth of E. senticosus was poor under the low light intensity(relative 20% of full sun-light) at the growing place of the habitat and the propagation was conducted by root sucker. The natural vegetation was consisted of big trees, 3 species; shrubs, 8 species and herbs, 4 species.

• Journal of environmental and Sanitary engineering
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• v.5 no.2
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• pp.105-116
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• 1990

Seungbong Island is situated about 100km away Inchon Port in the western sea of the Korean Peninsula. Field investigations were conducted for two days each from June 30 through July 1, 1981 and from August 20 through 21, 1981. The results obtained are summarized as follows: Plants growing in this island consist of a total of 193 species (70 families, 151 genera, 170 species, 22 varieties and 1 forma). Pinus thunbergii was confirmed to be the dominant species. The natural degree observed in this island was high, as a whole. The coefficient of ferny plants (Pte-Q) is 0.95, lower than grass. Atractylodes japonica Koidz., Miscanthus sinensis Anders. var. purpurascense Rendle, and Rhododendron mucronulatum Turz. are distributed mainly on the forest bed of Pinus thunbergii. The poor distribution of Chenopodium album var. centrorubrum Makino, Setaria viridis (L.) Beauv., Amaranthus mangostanus Linne is considered attributable to the phenomenon of allellopathy caused by a chemical substance secreted from the leaves of Pinus thunbergii. The component ratio of species in this island is lower than that of other islands due probably to the small area of arable land and grassland. The poor growth of plants in the forest of Pinus thunbergii, the dominant species in this island, seems to be attributed to the low relative light intensity of the forest. Seaside plants consisting of a total of 7 species were distributed mainly in the vicinity of sandy beaches. Naturalized plants comprising a total of 11 species were relatively diversified in the number of species.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.543-553
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• 2013

In Korea, there have been many studies and progresses on various types of pilot scale or commercialized field scale Best Management Practices(BMP) during the last 10 years. Runoff characteristics of diffuse pollutants from different land uses are well identified and documented. However, for the coastal area connected directly with shoreline, runoff patterns and management schemes of non-point pollution were not fully studied. Recently, coastal area is emerging as a new development axis especially in west coast side of Korea such as Incheon city and Chungnam province, thus urbanized area rapidly increased but there are no buffer zones and BMP facilities to aim at preventing direct discharge of the first flush into coastal sea and beaches. In this study, parking area in Deacheon harbor, Boryeong City in Chungnam Province was selected and rainfall runoff was monitored for two year period in order to examine run-off features from which proper type of BMP suitable for coastal area is proposed. Coastal area usually has a low ground water level and consists of plain land, so that large scale BMP such as storm water retention pond and wetland requiring great excavation works is not best management plan. In addition, monitoring study shows that storm water from the paved parking area has a high salinity compared with those in storm water from the inland. High salinity is detrimental for the vegetation. Therefore, BMP employing least vegetative cover and also in terms of maintenance is a good option such as infiltration trench and porous pavement.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.5
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• pp.440-453
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• 2005

Objectives : To develop a bioactive membrane for guided bone regeneration (GBR), the biocompatibility and bone regenerating capacity of the cellulose membrane obtained from the Ascidians squirt skin were evaluated. Materials and methods : After processing the pure cellulose membrane from the squirt skin, the morphological study, amino acid analysis and the immunoreactivity of the cellulose membrane were tested. Total eighteen male Spraque-Dawley rats (12 weeks, weighing 250 to 300g) were divided into two control (n=8) and another two experimental groups (n=10). In the first experimental group (n=5), the cellulose membrane was applicated to the 8.0 mm sized calvarial bone defect and the same sized defect was left without cellulose membrane in the first control group (n=4). In the another experimental group (n=5), the cellulose membrane was applicated to the same sized calvarial bone defect after femoral bone graft and the same sized defect with bone graft was left without cellulose membrane in the another control group (n=4). Each group was sacrificed after 6 weeks, the histological study with H&E and Masson trichrome stain was done, and immunohistochemical stainings of angiogenin and VEGF were also carried out. Results : The squirt skin cellulose showed the bio-inductive effect on the bone and mesenchymal tissues in the periosteum of rat calvarial bone. This phenomenon was found only in the inner surface of the cellulose membrane after 6 weeks contrast to the outer surface. Bone defect covered with the bioactive cellulose membrane showed significantly greater bone formation compared with control groups. Mesenchymal cells beneath the inner surface of the bioactive cellulose membrane were positive to the angiogenin and VEGF antibodies. Conclusion : We suppose that there still remains extremely little amount of peptide fragment derived from the basement membrane matrix proteins of squirt skin, which is a kind of anchoring protein composed of glycocalyx. This composition could prevent the adverse immunological hypersensitivity and also induce bioactive properties of cellulose membrane. These properties induced the effective angiogenesis with rapid osteogenesis beneath the inner surface of cellulose membrane, and so the possibilities of clinical application in dental field as a GBR material will be able to be suggested.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.545-551
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• 1998

The Radio communication by existing SSB, VHF, etc. in a coast station and a base station for military affairs is still used to a very important the device of information delivery or transmitting and receiving by the remote controller to using to the exclusive cable for a equipment established at a long distance. When a number of consumer to connected and operated by a number of transceiver is essential for a circuit controller of ICS, in KOREA, is devoted by import to considerable quantity because of to be delayed development of this field. This Paper has been realized to optimal algorithm and designing of a circuit connection controller by multi-processor to pre-stage for the development of ICS. The H/W is composed able to remote control to circuit connector with the several slave processor and a processor for master, and this has taken possible through without any obstacle to communication circuits of a control signal by FSK system. The S/W make possible monitoring for communication condition of other circuits by means of a serial communication system by the multi-processing. This paper has been studied for connecting to a circuits wished to rapidly and precisely by the full application to a interrupt technique. A technique to control by remote to a number of transceiver is a way increasing to application for a frequency resource of the limited MF/SF, VHF and the existing radio communication technique. According to, this paper will achieve to be the reduction of energy & equipment and multiplicity of information delivery in the general communication and disposal to rapid and exact for the important communication as distress, urgency and safety on the sea.

• The Journal of the Petrological Society of Korea
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• v.18 no.2
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• pp.137-151
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• 2009

Synthetic analyses of field data, including rock facies, contact relationships, petrography, structural elements, and etc., and previous geochemical and absolute age data of the Tertiary Churyeong Breccia and its surrounding volcanics in the Gyeongju city, Korea, have led to the following results. (1) The Tertiary rocks are divided into the dacitic tuffs, Churyeong Breccia, and andesitic rocks in ascending order. The dacitic tuffs are unconformably overlain by the Churyeong Breccia which is intruded by or conformably overlain by the andesitic rocks. (2) The dacitic tuffs are correlated with the Paleocene${\sim}$Eocene Wangsan dacitic volcanics, while the Churyeong Breccia and andesitic rocks are correlated with the early Early Miocene Andongri Formation and Yongdongri Tuffs in the Waeup Basin, respectively. (3) The Churyeong Breccia accumulated rapidly in the NE-trending graben about 1.5 km in width during the crustal extension in the NW-SE direction due to the East Sea opening. (4) Dacitic${\sim}$andesitic volcanism and crustal extension were active during the early Early Miocene times in SE Korean peninsula. During the deposition the Churyeong Breccia, especially, the volcanism ceased for some time, but the active normal faulting led to the formation of grabens in places.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.95-104
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• 2005

The research conducted to study the potential practicability of recycled aggregate concrete by analyzing the characteristics of concretes made of recycled quality aggregates produced by wet and dry process has found the following results. The air content of recycled aggregate concrete increased with increase of the substitut on rate due to mortar included while producing recycled aggregates. However, the concretes with aggregate produced by dry process had relatively low rate of increase in air content. The slump showed generally decreasing trend as the substitution rate of recycled aggregate increased regardless of the wet or dry process. It was assumed that the mortar particles remained in recycled aggregate absorbed the surplus hydration in concrete and decreased fluidity The compressive strength generally decreased as the substitution rate of recycled aggregate increased, however there was an increasing trend as well due to decreasing effect of water-cement ratio when the substitution rate of recycled aggregate reached 25, 50% after mix. This phenomena also appeared in early age, which meant that recycled aggregate concrete should not be retarded in setting when applied in the field. The tensile strength also reached the maximum when wet or dry recycled aggregate replaced with 25%. To conclude, recycled aggregates for concrete produced by wet or dry process are expected to demonstrate essential characteristics of concrete without significant decline in physical or dynamic quality when the substitution rate is below 25% although there are variations subject to water-cement ratio. However, slight differences are expected due to types of recycled aggregate and physical quality.

• Tunnel and Underground Space
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• v.21 no.4
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• pp.320-327
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• 2011

In this study, for stemming effect in blast of the mortar block body, the crushed granite sand as fine aggregate, which is waste rock obtained at the ○○ limestone mine, was investigated to compare with stemming materials such as sea sand, river sand, clayed soil and water can be acquired easily at the field. The mortar block body was manufactured with the dimensions of 50 cm width, 50 cm length and 70 cm height. The direct shear and sieve separator test were performed, and the properties of friction resistance were analyzed by the extrusion test for five stemming materials. Axial strain of steel bar and ejection velocity of stemming materials due to the explosive shock pressure in blasthole with the stemming length of 10 cm and 20 cm in the mortar blast test were measured by the dynamic data acquisition system. Among stemming materials, axial strain showed the largest value at the crushed granite sand as fine aggregate, and the ejection velocity was the smallest value at the stemming of water. The results has shown correlate with harden unit weight in blasthole, particle size distribution, shear resistance, and extrusion strength of stemming materials. The ejection velocity of stemming material at the mouth of blasthole and the axial strain of steel bar in the inside of blasthole tend to be inversely proportional to each other, represent exponentially.