• Journal of Mushroom
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• v.7 no.4
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• pp.182-186
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• 2009

Single ascospores was isolated in Yesan-gun, Chungnam in 2006 with Cordyceps militaris. This study was carried out to select the superior isolates which produce more fruiting body and contain more cordycepin contents. Five single ascospore isolates were cultured on brown rice pupae medium and they formed fruiting bodies. To select better isolates, each isolates was hybridized and then the characteristics and cordycepin contents were investigated. After biological efficiency and codycepin contents were examined, finally C0601S05 was selected. Top-cross test of isolate C0601S05 was carried with 29 single ascospores. From this test, isolate C0601S05${\times}$C0601S33 and isolate C0601S05${\times}$C0601S43 containing highest cordycepin contents were selected. Codycepin contents of C0601S05 was 246mg% and those of C0601S05${\times}$C0601S33 and C0601S05${\times}$C0601S43 were 325mg% and 280mg%, respectively. C0601S05${\times}$C0601S33 was registered as Yedang 3 at the Korea seed & variety service.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.101-109
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• 2019

This study investigated the characteristics of fish communities at the Lake Yedang, in 2013 to 2014 and 2017. During the survey period, there were 29 species of 10 families collected from 3 survey stations. Of them, Cyprinidae occupied 34.5% (14 species), Bagridae, Gobiidae 10.3% (3 species), and Cobitidae, Centrachidae were 6.9% (2 species) in the number of species, respectively. Korean endemic species were 4 species (13.8%) Abbottina springeri, Cobitis nalbanti, Pseudobagrus koreanus, Odontobutis interrupta and accounted for a low rate. There were 3 species (10.3%) exotic species including Carassius cuvieri, Lepomis macrochirus, Micropterus salmoides. As a result of community analysis, dominant index was 0.45~1.00, diversity index was 0.19~2.30 and richness index was 0.41~1.94.

• Journal of Mushroom
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• v.11 no.3
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• pp.124-130
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• 2013

The effects of environmental and nutritional requirement such as temperature, pH, different media, carbon, nitrogen, and carbon-to-nitrogen ratio on the mycelial growth of Cordyceps militaris strain 'Yedang 3' were studied. The optimum temperature and pH for the growth of mycelium were $20-25^{\circ}C$ and pH 6-7, respectively. Out of ten media tested, mushroom complete media (MCM) was the best medium for fast mycelial growth, and Sabouraud's dextrose agar yeast extract (SDAY), malt extract yeast extract agar (YMA) also were favored. The color and shape of colonies varied in different media. The best carbon sources for mycelial growth were fructose, mannitol, and sucrose, whereas the best nitrogen sources were tryptone and peptone. However, mycelia grew slowly in inorganic nitrogen compounds such as $NH_4Cl$, $(NH_4)_2SO_4$, $NH_4NO_3$, and $NaNO_3$. The optimum C:N ratio observed on the culture media was 30-40 range. These results provided basic information on cultural characteristics of vegetative growth and might be useful for spawn production in Cordyceps militaris.

• The Korean Journal of Ecology
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• v.21 no.1
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• pp.97-103
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• 1998

Yedang lake has so plentiful pondage and many species of fresh-walter-fish that a large number of people crowd around there all the year round. Most of them are not used to prevent tsutsugamushi disease spreading by chigger(T-mite). Accordingly, this study was carried out in order to obtain basic materials for prevention of this disease and the results are summarized as follows. The number of wild rat that captured in surveyed areas was sixty five(apodemus agrarius: 63, Rattus norvegicus: 2) during the period of a year and ration of captured rats to trap was about 8%. The dominant species of T-mite in all the surveyed areas were Leptotrombidium pallidum and L. palpale and the total number collected was 5782.9 with one family, two genra, eight species. The density of T-mites that collected from rats in three areas(Nodongri, Hatanbangri, Kyochonri) appeared $743.3{\pm}80.4,\;847.2{\pm}86.2\;and\;869.6{\pm}86.4,\;and\;in\;soil\;149.5{\pm}13.9,;154.7{\pm}14.7\;and\;182.4{\pm}20.8$ respectively. On the whole, the number of T-mite that collected from the rats was about three times as much as it in soil. The comparison of individual number of T-mite per a rat collected in three surveyed sites(A,B and C) showed 126.7, 243.1, 258.6 and per $2,000cm^3$ of soil 12.7, 12.7, 54.6, 103.5 respectively. In other word, the number of T-mite at site A and B is smaller than that at area C, thus comparing habitats of three sites each other, C is better living environment of rat and mite than that of A or B. Seasonl occuarance of t-mite that is from rat gradually was increased toward winter and showed the peak to January, and decreased since March but it in soil was inverse proportion to it from rats, because the larvae of T-mite that was hatched in soil was transmited to host in order to suck the body fluid.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.3
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• pp.63-69
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• 2020

Recently, the Yedang reservoir needs reflecting the demands of the public and administration, including change of reservoir status and paradigm shift of users, as well as planning programs to activate the area as a special health zone for tourism, leisure, recreation and experience at the local government level. Previous Optimum Equipment model (OEM) preferentially considers the creation of waterfront. This study shows the operation model for readjustment of water supply facilities according to the limit of the level of the beneficiaries. Results show the renovation cycle of Yedang tourist resort and the suspension bridge through developed model simulation. In addition to securing quantity for the supply of agricultural water and the function of water protection, the multi-function of the agricultural reservoir shall be re-evaluated to enhance the diverse availability of the agricultural reservoir. The county office should also boost various availability at various levels to revitalize the local economy, such as producing pleasant and safe places and offering safe food for people.

• Journal of Mushroom
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• v.13 no.3
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• pp.151-156
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• 2015

Cordyceps militaris is being studied and cultivated as a medicinal mushroom having many valuable biological and pharmaceutical activities. In the breeding of new C. militaris mushroom, single ascospores were isolated and examined their mycelial growth, mycelial density, and production of stroma and perithecia. Among them selected isolates were crossed and hybrids were produced showing high quality fruiting bodies on artificial media. Mycelial growth rate of new strain 'Dowonhongcho' was higher than that of better on 'Yedang 3' on SDAY at $10-25^{\circ}C$. The stromata of new strain were club-shaped and bright orange-red. Its height was 6.1 cm and the cordycepin content was 0.34% on average. The new strain showed 9% higher yield than 'Yedang 3' with producing firmer fruit bodies. The optimum temperature for mycelial growth was $22{\sim}25^{\circ}C$ and the optimum temperature for stroma development was $18{\sim}22^{\circ}C$. Fruiting bodies were began to produce 45 days later after inoculation. This new cultivar may serve as a valuable one for artificial cultivation and industrial-scale production of C. militaris.

• Journal of agricultural medicine and community health
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• v.6 no.1
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• pp.61-67
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• 1981

This survey was undertaken to evaluate the status of clonorchiasis in Chang-gok Myun, Hong-Seong Gun adjacent to Yedang reservoir from Sept., 1980 to Oct., 1981. A total of 550 subjects (male 318, and female 232) were examined by cellophane-thick smear technique and formalin-ether method. In order to identify the intensity of the Clonorchis sinensis infection, Stoll's egg dilution counting method was also applied to the C. sinensis positive cases. The following results were obtained in this survey; 1. In the examination of 550 subjects, Clonorchis sinensis eggs were found in 167 cases (30.4%). Male subjects showed 43.4% positive rates and female represented 12.5%. 2. The highest prevalence rate of Clonorchis sinensis was found in 40~49 year group in male (64.2%) and 30~39 year group in female (22.0%), although 14.3%~16.7% positive rates were found in young aged group. 3. Mean E.P.G. of Clonorchis sinensis infected cases were 6,148, showing 7,533 in male and 5,193 in female. 4. The degree of intensity of Clonorchis sinensis infection by E.P.G. count was distributed as 30.4% in light infection (1~999), 45.7% in moderate infection (1,000~29,999) and 5.8% in very heavy infection (over 30,000) in male. Female showed 48.3% in light, 37.9% in moderate, 10.3%. in heavy and 3.5% in very heavy infection. 5. Other helminthic infection rate was 15.6% in Ascaris lumbricoides infection, 15.1% in Trichuris trichiura infection and 4.4% of male subjects showed eggs of Taenia species.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.48-57
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• 2016

The distribution of fish (Cobitidae and Cyprinidae) and amphibians together with related environmental factors were surveyed at 30 randomly selected rice-fields (15 flooded unmanaged rice fields (FUR) and 15 unflooded managed rice fields (UMR)) near the Yedang reservoir in Korea, eight times from May to August in 2012. The total number of species captured from the entire survey area was 13 species with 8 families of fish and 5 species of amphibians. The number of species of Cyprinidae fish captured in FUR was higher than that in UMR. Upon the comparative analysis on the distribution of fish and amphibians in FUR and UMR, it was found that the number of Cyprinidae fish captured in FUR was significantly higher than that in UMR while the number of Cobitidae fish captured in UMR was higher than that in FUR. According to the analysis on the environmental factors that affect the distribution of fish, Cyprinidae fish tend to appear in rice-fields, that were flooded in winter, near the Yedang reservoir while Cobitidae fish tend to appear in rice fields that draws its water supply from forest reservoir and have a good water drainage system. In case of amphibians, the number of tadpoles captured in UMR was higher than that in FUR. Rana catesbeiana was dominant in FUR and Rana nigromaculata was dominant in UMR. Upon the analysis on the environmental factors that affect the distribution of tadpoles, it was found that Rana catesbeiana tadpoles tend to appear in rice fields, that were flooded in winter, near Yedang reservoir while Rana nigromaculata tadpoles tend to appear near mountains and far from the Yedang reservoir.

• Journal of the Korean earth science society
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• v.36 no.7
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• pp.632-642
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• 2015

Seismograms are composed of 3 characteristics, that is, seismic source, attenuation, and site amplification. Among them, site amplification characteristics should be considered significantly to estimate seismic source and attenuation characteristics with more confidence. This purpose of this study is to estimate the site amplification characteristics at each site using horizontal to vertical (H/V) spectral ratio method. This method, originally proposed by Nakamura (1989), has been applied to study the surface waves in microtremor records. It has been recently extended to the shear wave energy of strong motion and applied to the study of site amplification. This study analyzed the H/V spectral ratio of 6 ground motions respectively using observed data from 4 sites nearby in Yedang Reservoir. And then, site amplification effects at each site, from 3 kinds of seismic energies, that is, S waves, Coda waves energy, and background noise were compared each other. The results suggested that 4 sites showed its own characteristics of site amplification property in specific resonance frequency ranges (YDS: ~11 Hz, YDU: ~4 Hz, YDD: ~7 Hz). Comparison of this study to other studies using different analysis method can give us much more information about dynamic amplification of domestic sites characteristics and site classification.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.5
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• pp.35-42
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• 2011

This study is to check the applicability of SWAT-APEX (Soil and Water Assessment Tool-Agricultural Policy / Environmental eXtender) model as combined watershed and field models by applying the APEX to paddies in a watershed (465.1 $km^2$) including Yedang reservoir. Firstly, the SWAT were calibrated with 3 years (2000~2002) daily streamflow and monthly water quality (T-N and T-P) data, and validated for another 3 years (2003~2005) data. The average Nash-Sutcliffe model efficiency (ME) of streamflow during validation was 0.73, and the coefficient of determination ($R^2$) of T-N and T-P were 0.77 and 0.73 respectively. Next, running the SWAT-APEX model with the SWAT calibrated parameters for paddies, the $R^2$ of T-N and T-P were 0.80 and 0.76 respectively. The results showed that SWAT-APEX model was more correctly predicted for T-N and T-P loads than SWAT model. The difference results between watershed and field models was predicted to have substantial impact on NPS loads, especially on T-N and T-P loads. Therefore, to improve negative NPS load simulations should be considered the model characteristics as simulating mechanism to properly select the NPS model for agricultural watershed.