• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.283-291
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• 2004

Recently, the construction of underwater structures has been gradually increased, but underwater concrete got some problems of quality deterioration and water contamination around cast-in-situ of construction. In addition, massive underwater structures such as LNG tank, underwater concrete structures of large and continuous high- strength subterranean wall under water are being demanded lower heat of hydration. In this paper, the mechanical properties of high-strength antiwashout underwater concrete (HAWC) containing with two kinds of mineral admixtures respectively were investigated. On the basis of these results, the pH value and suspended solids of HAWC manufactured in the mock-up test were 10.0$\Box$11.0 and 51 mg/${\iota}$ at 30 minutes later, respectively, initial and final setting time were about 30,37 hours, and the slump flow was 530$\pm$20Tm. In the placement at a speed of $27 m^3/hr$, there was no large difference in flowing velocity with or without reinforcing bar, and flowing slope was maintained at horizontal level. Compressive strength and elastic modulus of the cored specimen somewhat decreased as flowing distance was far; however, those of central area showed the highest value.

• Journal of Environmental Science International
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• v.25 no.11
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• pp.1511-1519
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• 2016

Jeju Island relies on subterranean water for over 98% of its water resources, and it is therefore necessary to continue to perform studies on drought due to climate changes. In this study, the representative standardized precipitation index (SPI) is classified by various criteria, and the spatial characteristics and applicability of drought in Jeju Island are evaluated from the results. As the result of calculating SPI of 4 weather stations (SPI 3, 6, 9, 12), SPI 12 was found to be relatively simple compared to SPI 6. Also, it was verified that the fluctuation of SPI was greater fot short-term data, and that long-term data was relatively more useful for judging extreme drought. Cluster analysis was performed using the K-means technique, with two variables extracted as the result of factor analysis, and the clustering was terminated with seven-time repeated calculations, and eventually two clusters were formed.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.148-154
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• 2005

Ground-source (Geothermal) heat pump (GSHP) systems can achieve a higher coefficient of performance than conventional air-source heat pump (ASHP) systems. However, GSHP systems are not widespread in Japan because of their expensive boring costs. The authors have developed a GSHP system that employs the cast-in-place concrete pile foundations of a building as heat exchangers in order to reduce the initial boring cost. In this system, eight U-tubes are arranged around the surface of a cast-in-place concrete pile foundation. The heat exchange capability of this system, subterranean temperature changes and heat pump performance were investigated in a foil-scale experiment. As a result, the average values for heat rejection were 186${\sim}$201 W/m (for pile, 25 W/m per Pair of tubes) while cooling. The average COP of this system was 4.6 while cooling; rendering this system more effective in energy saving terms than the typical ASHP systems. The initial cost of construction per unit for heat extraction and rejection is ${\yen}$72/W for this system, whereas it is f300/W for existing standard borehole systems.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.4
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• pp.33-40
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• 2006

The quality of the supply water which is supplied to consumer is not the thing of water after filtrating but the thing of water from faucet through pipe. As a result, heavy metals and microorganism, that is the major materials, which cause the distrust of the supply water is generated by supply process. Especially, the heavy metal is generated by the corrosion of waterworks. Besides, rupture by corrosion of pipe becomes the factor of supply water's pollution in waterworks and the factor of pollution of the soil and environment in drain pipe. Therefore, this research examined the weight reduction electric potential measure to measure the corrosion degree of piping materials after testing the corrosion of piping materials(Copper Pipe, Galvanized Steel Pipe, Stainless Steel Pipe) which is generally used at the moment in various corrosion environments(subterranean water, supply water, 3.5% NaCl, 3.5% $HNO_3$). And let me show basic design data about problem occurrence such as leakage water, rust water, inside and outside corrosion from this.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.9
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• pp.641-647
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• 2010

Ground-source(Geothermal) heat pump(GSHP) systems can achieve a higher coefficient of performance than conventional air-source heat pump(ASHP) systems. However, GSHP systems are not widespread because of their expensive installation costs. The authors have developed a GSHP system that employs the cast-in-place concrete pile foundations of a building as heat exchangers in order to reduce the initial cost. In this system, eight U-tubes are arranged around the surface of a cast-in-place concrete pile foundation. The heat exchange capability of this system, subterranean temperature changes and heat pump performance were investigated in a full-scale experiment. As a result, the average values for heat rejection were 186~201 W/m(per pile, 25 W/m per pair of tubes) while cooling. The average COP of this system was 4.6 while cooling; rendering this system more effective in energy saving terms than the typical ASHP systems.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.6
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• pp.1-12
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• 2010

This study aims at analyzing the development status of surroundings of natural environment conservation areas and securing an adequate distance from development activities to conserve natural environment conservation areas efficiently or developing an improvement plan for setting conservation areas. Findings from the study shows that 1) rather than simply designating a legal natural environment conservation area, a conceptual scope approach of a "core area", "buffer area", and "transition area" such as in zoning of a "biosphere reserve" by UNESCO is recommended; 2) when setting an adequate range in a natural environment conservation area, it should be set by fully considering locational situation and the regional and environmental features of surroundings rather than setting a certain distance uniformly; 3) instead of designating wetlands only as a conservation area, entry and exit areas should be also included as buffer areas and in the case of wild animals, not only habitats but also feeding areas should be designated as conservation areas; and 4) an adequate horizontal separation space is important in the case of ground development, but for natural resources related to subterranean water and geological situation such as wetlands, an adequate vertical separation space should be fully considered.

• Journal of the Korean Wood Science and Technology
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• v.45 no.2
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• pp.159-167
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• 2017

Historical wooden buildings in Korea are being damaged by Reticulitermes speratus kyushuensis Morimoto, a type of subterranean termite, and the scale of this damage is increasing gradually because of global warming. This study evaluated the ingestion toxicity of the phenylpyrazole insecticide fipronil to R. s. kyushuensis and its applicability as termite bait with the aim of controlling termite colonies more efficiently. An ingestion toxicity assessment was conducted and the $LT_{50}$ was determined to be 4.43 day at concentrations of 10 ppm, indicating a slow-acting effect; therefore, 10 ppm was selected as an appropriate dose. A field applicability assessment was conducted in which the number of foraging workers and the rate at which the termites fed decreased 2 weeks after baiting, and termite colony activity was no longer apparent after 4 weeks demonstrating the efficacy of fipronil at eliminating colonies. Taken together, these results, indicate that low-dose fipronil eliminated R. s. kyushuensis colonies faster than insect growth regulators; therefore, it is expected to be useful when trying to conserve historical wooden buildings.

• Animal Systematics, Evolution and Diversity
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• v.2 no.1
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• pp.49-62
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• 1986

A taxonomic study was carried out on the freshwater copepods of Order Calanoida from Korean during the period from May, 1983 to November, 1984. Materials consist of both specimens deposited at the Department of Biology, Kangreung National University and the specimens collected from various freshwater regions (excluding the subterranean waters) such as rivers, lakes, ponds, bogs, ricefields, etc. during this period. As a result of examining the specimens collected at the 26 localities in South Korea, 8 species of 3 families were identified, of which 4 species are newly known from Korea ; Sinocalanus sinensis (Poppe, 1889) ; Tropodiaptomus oryzanus Kiefer , 1937 ; Sinodiaptomus sarsi (Rylov, 1923) ; Neodiaptomus schemackeri(Poppe et Richard, 1892).

• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.451-458
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• 2019

Jabon (Anthocephalus cadamba Miq.) is a fast-growing species that exhibits a lower natural resistance than that exhibited by the timber sourced from natural forests. Jabon's resistance to termite attack can be improved by impregnating its wood structure with poisonous organic materials. This study examined jabon's resistance to termite attack when impregnated with wood vinegar and an animal adhesive. The wood specimens were impregnated using sengon wood vinegar and an animal adhesive (8% and 10%, respectively) using a vacuum pressure machine. The specimens were tested for their resistance to subterranean and dry-wood termites according to Indonesian National Standard (SNI 7207-2014). The results denoted that jabon impregnated with wood vinegar and an animal adhesive concentration of at least 8% with the addition of 4% borate was effective to resist termite attacks. The impregnated jabon exhibited a lower weight loss and higher termite mortality when compared with those exhibited by the control specimens. Thus, the resistance class improved from class IV to class I.

• Animal Systematics, Evolution and Diversity
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• v.37 no.1
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• pp.19-25
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• 2021

Soldanellonyx monardi Walter, 1919, a halacarid species is newly recorded from South Korea, as the second member for the freshwater halacarid mites in Korea after S. chappuisi Walter, 1917 reported from Gossi-gul Cave, a limestone cave at Yeongwol in 1968. It was collected from three wells in the southeastern part of Korean peninsula this year. Korean specimens are well accorded with S. monardi s. str. in having telofemur I less than 1.5 times longer than wide, two spiniform setae on the ventral side of tibia I, relatively longer anterior dorsal plate (slightly longer than its width and about half the length of posterior dorsal plate), and the posterior epimeral plates lacking a dorsal seta. Based on the Korean specimens, a brief table for the morphological differences between adult females and deutonymphs are provided, which shows a tendency of rather consistent increment according to growth in the number of spiniform dorsal setae on telofemora and genua of legs I and II, the number of perigenital setae, and the number of genital acetabula. In this paper, detailed redescription and a brief table for the morphological differences between adult females and deutonymphs of S. monardi are provided.