• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.4
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• pp.25-42
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• 2018

The purpose of this study is to present the basic data for management of ecologically restored stream by surveying and analysing the vascular plants distributed in Chunghyocheon stream, Gyeongju-si. The survey of vascular plants in this site was conducted before and after restoration. The number of vascular plants were summarized as 276 taxa including 68 families, 188 genera, 242 species, 1 subspecies, 29 varieties and 4 forms. The rare plants were 2 taxa including Prunus yedoensis Matsum. and Iris ensata var. spontanea (Makino) Nakai, and the Korean endemic plant was Lespedeza maritima Nakai. The specific plants by floristic region were 13 taxa including 1 taxa of grade V, 3 taxa of grade III, 1 taxa of grade II and 8 taxa of grade I. The naturalized plants were 62 taxa including Persicaria orientalis (L.) Spach, Lepidium virginicum L., Poa compressa L. and so forth. The invasive alien plants were 3 taxa including Ambrosia artemisiifolia L., Aster pilosus Willd. and Lactuca scariola L.. The hydrophytes were 34 taxa including 26 taxa of emergent plant, 1 taxa of floating-leaved plant, 2 taxa of free-floating plant and 5 taxa of submerged plant.

• The Plant Pathology Journal
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• v.30 no.4
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• pp.432-436
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• 2014

The soil-borne ascomycete fungus Cylindrocarpon destructans causes ginseng root rot disease and produces various secondary metabolites such as brefeldin A and radicicol. The slow growth of this fungus compared with other plant pathogenic and saprophytic fungi in soil disturbs isolation of this fungus from soil and infected ginseng. In this study, we developed a selective medium for C. destructans using radicicol produced by this fungus. Supplementing 50 mg/L of radicicol to medium inhibited the mycelia growth of other fungi including Botrytis cinerea, Rhizoctonia solani and Alternaria panax, but did not affect the growth of C. destructans. In addition, conidia germination of other fungal species except for C. destructans was inhibited in submerged culture supplemented with radicicol. This medium provides a very efficient tool for isolating C. destructans and also can be used as an enrichment medium for this fungus.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1043-1048
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• 2012

We have researched the changes of paddy soil properties and rice yield by several different methods to treated with liquid pig manure(LPM). In the execution of this experiment, rice was cultivated to full maturity at a paddy field in Jeollabuk-do in 2011. Field experiment was designed with surface application on dry field condition+jet hose spray(Tr. 1), surface application on dry field condition+incorporation with irrigation water(Tr. 2), surface application on dry field condition+application device of fertilizer through irrigation(Tr. 3), submerged application on irrigated field condition+jet hose spray(Tr. 4), submerged application on irrigated field condition+incorporation with irrigation water(Tr. 5) and submerged application on irrigated field condition+application device of fertilizer through irrigation(Tr. 6) plot. Total N, P, K contents in used LPM were 0.44%, 0.07% and 0.14%, respectively. After the experiment, soil properties were not significant difference both several treated plots. But $NO_3$ and $NH_4$ contents at incorporation with irrigation water plots in paddy soil were higher than other plots. The yield was 602 kg $10a^{-1}$ in Tr. 2 plot compared Tr. 6 plot, which showed a value of 9.6% higher.

• Food Science and Preservation
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• v.6 no.3
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• pp.292-296
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• 1999

This experiment was carried out to investigate the growth status, grain yield and quality of the peanut submerged by the flood in grain filling time. The growth status and grain yield of peanut plant after flooding became worse as the flooded day increases and there was remarkable difference in quality between the submerged peanut for just one day and the unsubmerged peanut. For the storage period, the acid value of lipid extracted from submerged peanuts was increased, and the content of linoleic acid of that decreased as the day of submergence became longer. The content of N, P2Of and MgO in peanut plant was increased but the content of K$_2$O was decreased as the submergence duration became longer and the content of soil components were remarkably decreased after submergence. Thus the flooding during the grain filling period caused serious reduction in grain yield and quality of peanut, and more serious reduction was occurred due to longer duration of submergence.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.461-462
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• 2013

In this paper, a studied the SAW system being developed shipbuilding and plant industry with changing welding method to progress productivity. It studies a SAW system using one sensor instead previous one which is using two sensors. It suggests SAW system which has AC output with high current makes high speed welding and DC output with accurate arcing makes detailed control.

• The Plant Pathology Journal
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• v.15 no.1
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• pp.28-33
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• 1999

Phytophthora root rot of Chniese cabbage and spinach is reported for the first time in Korea. The diseases ocurred at Yangju, Seosan and Yeocheon in Korea from 1995 through 1998, mainly in lowland and submerged areas. Symptoms consisted of stunt, yellows, wilt and eventual death due to root rot. Fourteen isolates collected from naturally infected plants were all identified as P. drechsleri based on mycological characteristics. PCR-RFLP analysis of rDNA of the isolates confirmed the above result, since the restriction band patterns of the small subunit and internal transcribed spacers were identical to P. drechsleri and P. cryptogea, but distinct from closely related species of P. erythroseptica, P. cambivora, P. sojae and P. megasperma. The pathogen showed strong pathogenicity to Chinese cabbage, moderate to spinach, radish, cabbage and tomato, and weak or none to brown mustard, kale, chicory and pepper in pathogenicity tests.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.2
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• pp.39-50
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• 2018

In this study, the nonlinear interaction of irregular waves with wave breaking and currents around permeable submerged breakwater was investigated with the aid of olaFlow model which is open source CFD software published under the GPL license. The irregular wave performance of olaFlow applied in this study was verified by comparing and evaluating the target frequency spectrum and the generated frequency spectrum for applicability to irregular waves. Based on the applicability of this numerical model to irregular wave fields, in the coexistence fields of irregular waves and currents, the characteristics of wave height, frequency spectrum, breaking waves, averaged velocity and turbulent kinetic energy around porous submerged breakwater with the respect to the beach type and current direction versus wave propagation were carefully investigated. The numerical results revealed that the shape of wave breaking on the crown of the submerged breakwater and the formation of the mean flow velocity around the structure depend greatly on the current directions and the type of the beach. In addition, it was found that the wave height fluctuation due to the current direction with respect to the wave propagation is closely related to the turbulent kinetic energy.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.6
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• pp.361-374
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• 2016

When the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure is generated significantly due to pore volume change associated with rearrangement soil grains. This effect leads a seabed liquefaction around and under structures as a result from decrease in the effective stress, and the possibility of structure failure is increased eventually. These facts shown above have been investigated in the previous studies related to regular and irregular waves. This study suggested a concrete mat for preventing the seabed liquefaction near the submerged breakwater. The concrete mat was mainly used as a countermeasure for scouring protection in riverbed. According to installation of the concrete mattress, the time and spatial series of the deformation of submerged breakwater, the pore water pressure, and the pore water pressure ratio in the seabed were investigated. Their results were also compared with those of the seabed unprotected with the concrete mat. The results presented were confirmed that the liquefaction potential of seabed under the concrete mattress is significantly reduced under regular wave field.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.4
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• pp.166-179
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• 2018

This study aims at numerically investigating the water-surface characteristics such as wave height distribution depending on the current direction around the three-dimensional permeable submerged breakwaters in wave-current coexisting field which has not been considered in detail so far. In addition, the characteristics of the velocity field including the average flow velocity, longshore current and turbulent kinetic energy, which act as the main external forces of formation of salient, are also examined. For numerical analysis, olaFlow which is open source code of CFD was used and the numerical tests included different types of target waves, both regular waves and irregular waves. Numerical results indicated that wave height variation with wave following or opposing a current behind the submerged breakwater is closely related to turbulent kinetic energy. Furthermore, it was found that weaker longshore currents are formed under wave-current coexisting field compared to the non-current conditions, and transport flow is attenuated. As a result, it was possible to understand the influence of current existence and direction (following and opposing) on the formation of the salient formed behind the submerged breakwaters.

• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.403-411
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• 2013

This study was performed to examine whether it is possible to promote rice growth by midsummer drainage without damage of golden apple snails in environment-friendly rice farming. The effect of drainage on the life of snails was examined in a greenhouse before the filed experiment. Spats (young shells) of snails survived 100% at 12 days after drainage, and 93.3% at 15 days after drainage. The midsized shells survived 100% at 9 days, 93.3% at 12 days, and 86.6% at 15 days after drainage. In the field experiment, 10-days drainage did not affect the snail population and there was no significant difference of weeding activity of snails between the midsummer drainage treatment and the continuous submerged treatment. The plant height and the effective tiller number in the midsummer drainage treatment were higher than those of the continuous submerged treatment. The rice yield of midsummer drainage plot was 511kg/10a, which was 66kg/10a higher than 445kg/10a of continuous submerged plot. In conclusion, midsummer drainage could increase rice growth and yield without damage of golden apple snails in the environment-friendly rice farming.