• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1632-1638
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• 2011

Electric cables are one of the most important components in a nuclear power plant since they provide the power needed to operate electrical equipment. Despite their importance, cables typically receive little attention since they are considered passive, long-lived components that have been very reliable over the years when subjected to the environmental conditions for which they were designed. The operating experience reveals that a defect of the insulator or poor construction causes the initial failure of cable. However, the number of cable failures increase with plant aging, and these cable failures are occurring within the plants' 40-year licensed period. These cable failures have resulted in plant transients, shutdown, loss of safety functions or redundancy, entries into limiting conditions for operation, and challenges for plant operators. Therefore, diagnosis of MV cable installed in NPPs has become one of the most urgent issues in recent years. In accordance with PSR, condition maintenance for cables is also continuously required. Recently, HFPD tests have been widely performed to diagnose cable in the transmission and distribution cable system. However, on-line HFPD wasn't used in the NPPs because of the danger of plant shutdown, measurement sensitivity and application problems, etc. In this paper, HFPD measurement with portable device was performed to evaluate the integrity of the 4.16kV & 13.8kV cable lines. The test results show that HFPD is highly attractive to the diagnosis of MV cables in NPP by high detection sensitivity on-site.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.1
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• pp.141-154
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• 2012

This study was launched to verify the effective composition of plant species and its management program most suited for the dredged soiled area near Nakdong River Site 14. The improvement methods of planting base and the composition of plants such as silver grass, reed, and some colonies in aesthetic effect were studied. To search the management methods to decrease the confining pressure risen from the burried seeds which would consequently harm the previously seeded plants, experimental construction process was measured on the site. The purpose of this experiment was to figure out which part of the improvement on the plant base has the most significant effect for the revegetation of infertile, dredged soil, to verify the easily seeded, developing plants among seeded plants, and finally, to find the restoration model using plants near the dredged soil around riverside. 8 seeded plants and 23 invaded species were appeared which among the emerged plants, development of Aster yomena MAKINO, Lotus corniculatus var. japonica Regel, Trifolium repens L, and Dianthus longicalyx Miq were proved to be brought up well. Difference risen from the seed composition were not noticeable until 150day since the germination was proceeded mainly by Aster yomena MAKINO. The experimental plot with dredging sand+organic fertilizer method of construction and dredging sand+soil conditioner method showed most development while the effect of the plot with only the soil base of dredging sand stayed low. Another important method for the management of infertile, dredged soil base would be the removal of disturbing species which the experiment showed the tied relationship between the removal of disturbing species and development of seeding plants. Although this study was carried out focused on the Nakdong River Project, the study suggests the general management program that the removal of disturbing species such as Humulus japonicus Sieboid & Zucc. and Pueraria lobata (Willd.) Ohwi in times around rainy season(60days after seedling) would be effective for the easy growth of revegetation plants.

• The Korean Journal of Ecology
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• v.26 no.3
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• pp.103-108
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• 2003

This study examined the coastal sand dune vegetation before and after the construction of an embankment on Anmado Island in order to compare vegetation in relation to the development of islands. A total of 24 species distributed on the sand dunes. 18 species were found to be in common before and after the construction of the embankment, which included Vitex rotundifolia, Imperata cylindrica var. koenigii, Zoysia sinica, etc. The species which were not found in this survey included Rumex japonicus, Setaria viridis, Portulaca oleracea, Artemisia japonica, Poiygonum aviculare, etc, and new species included Arena fatua, Carex boottiana, Lycium chinense, Leonurus sibiricus, Torilis japonica, Solanum carolinense, etc. The washing away of sand brought about the changes in habitat and the increase in naturalized plants, which included Oenothera odorata, Lepidium apetalum, Bidens bipinnata, Erigeron canadensis, Datura stramonium, Xanthium strumarium, Arena fatua, Solanum carolinense etc. In addition, the disturbance to this habitat led to the changes in vegetation. The main plant communities in the surveyed site were classified as Vitex rotundifolia-Imperata cylindrica var. koenigil community, Zoysia sinica-Calystegia soldanella community and Messerschmidia sibirica community. The sand dune vegetation on Anmado Island changed with regard to the community and the composition of species after the construction of the embankment, due to the sand being severely eroded. While Vitex rotundifolia community and Commelina communis community were found before the construction of the embankment, they were replaced by Vitex rotundifolia-Imperata cylindrica var. koenigii community, Zoysia sinica-Calystegia soldanella community and Messerschmidia sibirica community, after the construction of the embankment.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.2
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• pp.273-280
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• 2010

This study aims to research into a plan for the spatial design on the major facilities in new-town region in Mongolia by using the spatial analytical technique in GIS. In case of Mongolian region, the demand for new-town development is rapidly increasing around Ulaanbaatar, where is the capital. On the other hand, the adequately relevant ground or the spatial-design technique is failing to be applied. This study extracted the region available for developing new down by using spatial analytical technique in GIS, and researched into the spatial-design plan for housing complex, filtration plant, sewage disposal plant, power plant, general park, crematory. The housing complex in the targeted region could be known to be adequate to be positioned around watercourse and road. It could be known to be adequate for filtration plant, which is the source of drinking water, to be located in the upper-stream region of a river, which is secured good quality of water, and for sewage disposal plant to be located in the lower-stream region available for minimizing occurrence of contamination. It is judged to be required for a proposed site of power plant to be located in the upper-stream region, for the park unit, which is space of the living culture, to be repaired and expanded the existing facilities, and for traffic network to be expanded through predicting demand along with new-town development. It is judged to be probably needed to be reflected even the flexible aspect for changing design through surveying the feasibility and economic efficiency on the future spatial design.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.2
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• pp.75-86
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• 2004

This study aims to figure out ecological characteristic of natural forests focusing on vegetation as a way of ecological renovation for the restoration of naturalness for golf courses that were constructed in the Country and to present vegetation models and appropriate tree species for the purpose. The study site is P golf club, which is located in Gapyong-gun, Kyeonggi Province. The site is within a forest where the grade from the natural ecology map is the first one and the level from the green index accounts for the eight, thus showing a typical environment for a golf course in terms of location. The location of the site explains a reason for restoration. The major substance of the study is to conduct ecological evaluation of vegetation structures around and inside the golf course and to present a vegetation model. In order to evaluate the ecological characteristics of the vegetation structures, the analysis of the study covered succession stages, multi-layer vegetation structures and species diversity. Plant communities that have high species diversity were selected for the vegetation model and proper density and species were proposed considering the number of species and individuals and distances between trees. The vegetation restoration model targets succession into an oak forest. Within a unit of 100 $m^2$, the recommended model include a tall-tree layer with 11 trees such as Quercus serrata and Quercus mongolica, a sub-tall-tree layer with 12 trees including Quercus mongolica, Quercus serrata, Prunus sargentii, Fraxinus rhynchophylla and Acer pseudo sieboldianum, a shrub layer with 32 trees from 16 species, and a grass layer with a cover rate of 45 %. The proposed vegetation restoration model needs to apply to : 1) damaged natural forests by the construction of golf courses; 2) boundaries between golf courses and surrounding forests; 3) buffer zones; 4) open spaces in between courses; and 5) areas between greens and tees where open spaces are available in a mass. In conclusion, one of the most important factors in presenting a vegetation model for the restoration of naturalness in the golf course and other damaged forests is to provide multi-layer vegetation structures that are composed of native species. As for the specific application for the site, it is recommended to manage the vegetation in such a way that the environment of the site can have a similar environment to the surrounding forest which is expected to succeed into an oaks-dominant one.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.965-975
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• 2014

Pretension PSC (Prestressed Concrete) members are subjected to a certain limit of size as they are generally produced in the off-site plant and transferred to the site due to the large scale of the product on system. In this study, a portable pretensioning production system has been developed, which allow us to apply the pretension method on site. Considering that a 50m span PSC girder using the pretension method requires a pressing device to endure a large jacking force, the portable pretension production system has to ensure safety against such a large pretension jacking force. In this study, the portable pretensioning system to produce a 50m span pretension girder was manufactured by using CFT (Concrete Filled steel Tube) members. In order to understand the stability of the system and the behavior of the elements, a static loading test was conducted and the stability of the proposed portable pretensioning production system was confirmed. The developed portable pretension system was applied to several construction sites and was investigated the problems on site. During the pretension girder and slab members that was producted by this pretension system in construction site, it has be found the several advantages such as simple fabrication processes, reduction of prestress-loss, and a decrease of 15% compared with the fabrcation cost of post-tension girder. After due consideration of the problems, this portable pretension system will be improved.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.4
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• pp.169-179
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• 2017

This study was conducted to supply information that can be utilized as data for desalination plant construction in the future by estimating unit cost of water production in the potential site of Incheon, Daesan, Yeosu, Busan, Ulsan and Sokcho in Korea. The production costs in Sokcho and Ulsan were similar to those of Busan and Yeosu. Those four sites showed better economic range due to low construction cost for intake facility compared to Incheon and Daesan. Although the salinity measured in the above 6 sites did not show perceptible effect on the production cost, the difference of seasonal seawater temperature needs to be considered due to the change of flux in reverse osmosis (RO) membrane. It turned out that the most critical parameters are the amortization in a year by the analysis of life cycle and the capacity of plant. Incheon and Daesan showed the difference of production cost up to 29% at the condition of amortization in 25 year, and up to 22% depending on plant capacity. However, the production cost in this study did not take into account of other indirect costs, therefore, this should be considered as the minimum cost.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.3
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• pp.179-188
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• 2015

This study reviewed the type of the project and developmental plan related to ocean energy development in the coastal land boundaries and the ocean, and suggested the efficient scoping method through the diagnosis of the key items of environmental impact assessment (EIA) in the coastal area. The major projects are the construction of tidal power plant, tidal current power plant, and offshore wind power plant in the public water, and also those are the construction of solar power plants in the coastal land boundaries. While the project plans on a large scale such as the construction of tidal power plant, it is important to consider both property of usefulness of the designated areas and harmony analysis with marine space availability based on the adequacy of the site selection and relevance of plan with the master plan for reclamation and strategic environmental assessment (SEA). And also it needs to be considered the careful checkup on the EIA checklist referring to the type of project, effective post-monitoring, and suggestion of mitigating methods to minimize the environmental impacts during the stage of actual environmental impact assessment. Introduction of a system of integrated marine environmental impact assessment should be considered for reasonable and effective manage to developmental projects on the marine spatial area.

• Journal of Wetlands Research
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• v.11 no.1
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• pp.39-48
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• 2009

Wetland plants are an important component for wetland design and construction because they determine functions of wetlands through interactions with the abiotic environment such as wetland soil and hydrology as well as with other wetland organisms. In this study, germination experiments with soils from a natural wetland that contain seeds of wetland plants were conducted in wetland mesocosms to investigate the applicability of natural wetland soils for introducing and establishing wetland plants into constructed wetlands. Seven species were germinated in the experiment, with two new species that were not found in the field survey of wetland plants in the West Nakdong River area, Korea. The number of plant individuals germinated in submerged conditions (15 individuals) was much greater than that in waterlogged conditions (2 individuals). In experiments in which soils from a natural wetland and a wetland construction site were mixed at different ratios, the largest number of plant individuals was observed in the condition with 100% natural wetland soil. The highest growth was observed at 50% natural wetland soil for Hydrilla verticillata and 100% for Ceratophyllum demersum. These results suggest that 1:1 mixture of soils from natural wetland wetlands and wetland construction sites would provide an appropriate condition for secure establishment of submerged plants in constructed wetlands.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.228-234
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• 1994

Genomic RNA was extracted from Cy strain of odontoglossum ringspot tobamovirus (ORSV-Cy) isolated from infected leaves of tobacco cv. Samsun. Size of the genomic RNA was about 6.6 kb in length. The genomic RNA was fractionated using Sephadex G-50 column chromatography into 2 fractions. They were polyadenylated at their 3'-end using E. coli poly(A) polymerase. Polyadenylated viral RNA was recovered by oligo (dT) primer adapter containing NotI restriction site and Moloney murine leukemia virus SuperScript reverse transcriptase (RNase H-). Second-strand cDNA was synthesized by using E. coli DNA ligase, E. coli DNA polymerase I and E. coli RNase H. Recombinant plasmids containing cDNAs for ORSV-Cy RNA ranged from about 800 bp to 3,000 bp. Among the selected 238 recombinants, pORCY-124 clone was the largest one covering 3'-terminal half of the viral RNA. This clone contained two restriction sites for EcoRI and XbaI and one site for AccI, AvaI, BglII, BstXI, HindIII, PstI, and TthIII 1. respectively. The clone contained partial viral replicase, a full-length movement protein and a complete coat protein genes followed by a 3' untranslated region of 414 nucleotides based on restriction mapping and nucleotide sequencing analyses. Clones pORCY-028, -068, -072, -187 and -224 were overlapped with the pORCY-124. Clones pORCY-014 and -095 covered 5' half upstream from the middle region of the viral RNA, which was estimated based on restriction mapping and partial sequence analysis. Constructed cDNA library covered more than 90% of the viral genome.