• The Plant Pathology Journal
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• v.36 no.1
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• pp.67-75
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• 2020

Tomato spotted wilt virus (TSWV) is one of the plant viruses transmitted by thrips and causes severe economic damage to various crops. From 2008 to 2011, to identify natural host species of TSWV in South Korea, weeds and crops were collected from 5 regions (Seosan, Yesan, Yeonggwang, Naju, and Suncheon) where TSWV occurred and were identified as 1,104 samples that belong to 144 species from 40 families. According to reverse transcription-polymerase chain reaction, TSWV was detected from 73 samples from 23 crop species, 5 of which belonged to family Solanaceae. Additionally, 42 weed species were confirmed as natural hosts of TSWV with three different life cycles, indicating that these weed species could play an important role as virus reservoirs during no cultivation periods of crops. This study provides up-to-date comprehensive information for TSWV natural hosts in South Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.237-244
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• 2013

Radar remote sensing is appropriate for monitoring rice because the areas where this crop is cultivated are often cloudy and rainy. Especially, Synthetic Aperture Radar (SAR) can acquire remote sensing information with a high temporal resolution in tropical and subtropical regions due to its all-weather capability. This paper analyzes the relationships between backscattering coefficients of rice measured by RADARSAT-2 SAR and growth parameters during a rice growth period. We examined the temporal variations of backscattering coefficients with full polarization. Backscattering coefficients for all polarizations increased until Day Of Year (DOY 222) and then decreased along with Leaf Area Index (LAI), fresh weight, and Vegetation Water Content (VWC). Vertical transmit and Vertical receive polarization (VV)-polarization backscattering coefficients were higher than Horizontal transmit and Horizontal receive polarization (HH)-polarization backscattering coefficients in early rice growth stage and HH-polarization backscattering coefficients were higher than VV-polarization backscattering coefficients after effective tillering stage (DOY 186). Correlation analysis between backscattering coefficients and rice growth parameters revealed that HH-polarization was highly correlated with LAI, fresh weight, and VWC. Based on the observed relationships between backscattering coefficients and variables of cultivation, prediction equations were developed using the HH-polarization backscattering coefficients.

• Animal Systematics, Evolution and Diversity
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• v.34 no.1
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• pp.23-26
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• 2018

Because of the potential negative influence on their hosts, ecto-parasites are of prime importance to numerous species. Ticks are among these, distributed worldwide, and potentially transmitting diseases while sucking blood of diverse hosts. The leopard cat (Prionailurus bengalensis euptilura Elliot, 1871) is the only felid left in the Republic of Korea following widespread anthropogenic disturbances that have resulted in the extinction of both Panthera species: the Siberian tiger(Panthera tigris altaica Temminck, 1844) and Amur leopard (P. pardus orientalis(Schlegel, 1857)). This study identifies ticks collected from a roadkill leopard cat retrieved in Seosan area in the Republic of Korea. Two ticks attached to the facial area of the carcass were identified as Japanese hard ticks, Ixodes nipponensis, based on mitochondrial cytochrome oxidase I. The matching sample was from Japan with 99.7% similarities, and the only available sequence on GenBank. This study reconfirms that I. nipponensis parasitizes the endangered leopard cat P. bengalensis euptilura.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.6
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• pp.37-47
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• 2008

Photovoltaic power generation is currently being recognized as one of the most popular sources for renewable resources over the country. Although it is also being adapted to rural area for may reasons, it is important to estimate the magnitudes of power outputs with reliable statistical methodologies, while applying historical daily solar energy data, for correct feasibility analysis. In this study, one of the well-known statistical methodologies is employed to define the appropriate probability distributions for monthly power outputs for the selected rural area, county of Seo-san, province of Chungnam. The results imply that the assumption of normal distributions for several months may lead to incorrect decision-making and therefore lead to the unreliable feasibility analysis. Generalized beta and triangular distributions were found to be superior to normal distribution, when describing monthly probability distributions for daily photovoltaic power. Based on the appropriate distributions resulted from this study, Monte Carlo simulation technique was also applied to provide additional flexible information for the relevant decision makers. This study found out new finding that the probability distributions should be considered to make planning of the photovoltaic power system in rural village unit, in order to give reasonable economic analysis to the decision makers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.97-102
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• 2001

This study was carried out to survey the weed distributions in 6 areas(Suwon, Seonghwan, Seosan, Taekwanryeong, Namwon and Yeongam) and to investigate the ecological characteristics of exotic weeds from 1997 to 1999. Total 44 species in 15 families of exotic weds were observed in grassland and forage crop field. Among them 4 species in 1 family were monocotyledonous and 40 species in 14 families were dicotyledonous weeds. Most common species among exotic weeds examined in this study were Rumex acetosella, Rumex crispus. Chenopodium album, Abutilon theophrasti, Amaranthus retroflexus, Polygonum orientale etc. Inedible weeds with hairs, prickles, fetor or poison were Solanum carolinense Xanthium strumarium, Datura stramnium, Erechtites hieracifolia, Anthemis cotula, Phytolaca americana etc. The relative density of Phytolaca americana increased with decreament of soil pH and content of available phosphate, and that of Solanum carolinense increased with decreament of soil pH and increament of available phosphate. Most of exotic weed seeds germinated well under light condition with $25~30^{\circ}C$, and some of those were hard or dormant seed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.103-108
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• 2001

This study was carried out to investigate the introduced route of exotic weeds and the effects of herbicide treatment. Herbicide trial was arranged as a completely randomized block design with treatment 1(\circled1 Dicamba $1\ell$/ha, \circled2 Mecoprop $5\ell$/ha, \circled3 Bentazone $3\ell$.ha, \circled4 Glyphosate $4\ell$/ha and \circled5 Pyrazosulfuron-ethyl 2kg/ha), and treatment 2(\circled1 Dicamba $2\ell$/ha, \circled2 Dicamba $4\ell$/ha, \circled3 Glyphosate $6\ell$/ha, \circled4 Glyphosate 4+Dicamba $1\ell$/ha and \circled5 Glyphosate 4+dicamba $2\ell$/ha) against 10 exotic weed species, and conducted in Suwon, Seosan and Yeongam from 1997 to 1999. Exotic weeds have been mostly introduced within imported cereals for concentrate feed or within seeds for forage production. Most of exotic weeds in forage crop field were controlled more than 95% by herbicide, but it was desirable that the control of exotic weeds was abreast of chemical and ecological method.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.3
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• pp.225-231
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• 2015

Improving current pasture productivity by precision management requires practical tools to collect site specific pasture biomass data. Recent developments in unmanned aerial vehicle (UAV) technology provide cost effective and real time applications for site specific data collection. For the mapping of herbage biomass (BM) on a hill pasture, we tested a UAV system with digital cameras (visible and near-infrared (NIR) camera). The field measurements were conducted on the grazing hill pasture at Hanwoo Improvement Office, Seosan City, Chungcheongnam-do Province, Korea on May 17 and June 27, 2014. Plant samples were obtained from 28 sites. A UAV system was used to obtain aerial photos from a height of approximately 50 m (approximately 30 cm spatial resolution). Normalized digital number (DN) values of Red and NIR channels were extracted from the aerial photos and a normalized differential vegetation index using DN ($NDVI_{dn}$) was calculated. The results show that the correlation coefficient between BM and $NDVI_{dn}$ was 0.88. For the precision management of hilly grazing pastures, UAV monitoring systems can be a quick and cost effective tool to obtain site-specific herbage BM data.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.294-299
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• 2002

PM (Particulate Matter) samples contained fungal spores were collected in the ambient air of Seosan, west Korea, in springtime of 2000 and 2001. PM concentrations were $199.8\mu{g}\;m^{-3}$ in the 1st Asian Dust Storm period (March, 23 ~ 24) and $249.4\mu{g}\;m^{-3}$ in the 2nd period (April, 7~9), 2000. Compared with the concentrations in 2000, relatively low PM concentration ($157.3\mu{g}\;m^{-3}$ ) was measured in the Asian Dust Storm period (April, 24 ~ 20) of 2001. Although there were somewhat differences for the total PM concentrations among the three periods, majorities of the PM were composed of coarse particles sized about 5 ~ 6 $\mu{m}$ over the periods of the two years. Diverse molds grown from fungal aerosols were observed in the PM samples and identified at the genus level. All the genera, Fusarium, Aspergillus, Penicillium, Basipetospora, Epicoccum and Monotospora are hyphomycetes in the division Fungi imperfecti (Deuteromycota). Especially, morphologically more diversified mycelia of hyphomycetes were grown on the fine PM sample (1.1 ~ 2.1 $\mu{m}$) than coarse PM samples in the periods of 2000. Furthermore, some molds were grown on even the background PM sample less than 0.43 $\mu{m}$ in the period of 2001. It was thought that some kinds of ultra fine sized fungal spores were transported by the Asian Dust Storm and suspended in the ambient air of study area during the events.

• The Korean Journal of Ceramics
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• v.6 no.3
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• pp.318-321
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• 2000

Most compressive strengths commonly used in the construction field are in a range of 240 to 300 kgf/$\textrm{cm}^2$ at 28 days. To get this rage of strengths, however, high-flowing concrete requires cementitious binders more than 400 to 450 kg/$\textrm{cm}^2$ for preventing segregation and sedimentation of aggregates. This amount of cementitious binder generates a large emission of excessive hydration heat, which may consequently induce harmful cracks in concrete structure. In order to reduce excessive hydration heat, thus, this paper aims at fabricating a high-flowing concrete under the condition that cement content is kept as low as 350kg/$\textrm{cm}^3$ by using viscose agents. In a parametric study, effects of cement types such as a ternary blended cement and Type V on he physical characteristics of high-flowing concrete were evaluated. In addition, the influence of viscosity was also investigated by applying two different viscose agents, one in a range of 6,000 to 10,000 cps and the others of 10,000 to 14,000 cps. In terms of chemical admixtures used in concrete mixture, the superplasticizer was Sulfonated Melamine-Formaldehyde Condensate with about 30,000 of molecular weight, and main component of viscose agent was HPMC (Hydroxy Propyl Methyl Cellulose). Slump flow was fixed at 50cm with different dosages of superplasticizer in weight.

• Korean Journal of Agricultural Science
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• v.17 no.1
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• pp.65-75
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• 1990

This study is purposed to examine how fanner's living conditions and managements have been improved during the last five years(1985 through 1989) on the basis of the information got from the sample survey of 30 farm households chosen in Galma-ri, Buseok-Myeon, Seosan county, Chungnam province. The followings are major results of the study. (1) There have been much improvement of kitchen facilities and increasing number of cultural goods, but not much in the condition of sanitation facilities. (2) The size of farm warehouse and stall have been greatly enlarged and there has been large variation in the heads of big animals such as cattle during the surveyed period. This may reflect the facts that farm managements become more diversified and commercialized. (3) It is shown that fanners more voluntarily accept new fanning techniques about their concerning crops. Also there have been rapid changes in the pattern of upland cropping system, adjusting to the commercialization of agriculture. (4) Currently, fanners tend to react to the price signal of market system more sensitively than before. Accordingly, agricultural income structure is varied subject to price fluctuation in the short run period.