• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.3
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• pp.141-148
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• 2022

In this study, the structural behavior of reinforced concrete members under simultaneous axial and blast loads was analyzed. Nonlinear dynamic analysis verification was performed using the experimental data of panels under fundamental blast load as well as those of reinforced concrete columns subjected to axial and blast loads. Because Autodyn is a program designed only for dynamic analysis, an analysis process is devised to simulate the initial stress state of members under static loads, such as axial loads. A total of 80 nonlinear dynamic finite element analysis procedures were conducted by selecting parameters corresponding to axial load ratios and scaled distances ranging 0%~70% and 1.1~2.0 (depending on the equivalent of TNT), respectively. The structural behavior was compared and analyzed with the corresponding degree of damage and maximum lateral displacement through the changes in axial load ratio and scaled distance. The results show that the maximum lateral displacement decreases due to the increase in column stiffness under axial loads. In view of the foregoing, the formulated analysis process is anticipated to be used in developing blast-resistant design models where structural behavior can be classified into three areas considering axial load ratios of 10%~30%, 30%~50%, and more than 50%.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.74-83
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• 1983

Yield losses due to diseases and insect pests were mentioned and emphasized the efficiency of resistant cultivars in curving the yield losses and increasing chemical efficiency. Present status of resistance breeding for blast, bacterial leaf blight viruses, brown planthopper and white backed planthopper were introduced and the resistance sources for those are discussed. Breeding strategies for above items were presented. Specially for the blast resistance, discussions were made in some detail. With brief future prospects of resistance breeding in Korea, a suggestion was made for pathologists to make clear about whether the blast spores will be brought from mainland China as we see with Bph and Wbph or not.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.239-240
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• 2009

Through the test of concrete panel, we evaluate quantitatively the blast resistance performance of concrete structure. In this blast test, eight different panels were tested and the main variables are concrete strength(200 MPa, 24 MPa) and retrofitting materials(CFRP, PolyUrea, BFRP).

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.231-236
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• 1996

한국에서 재배되고 있는 벼 품종의 도열별에 대한 지속저항성 품종을 조기에 선발, 보급할 수 있는 방법을 보색하기 위하여 1985년부터 1994년까지 온실 유묘검정, 밭못자리 및 포장검정을 통하여 저항성 정도를 평가하고 재배면적과 재배기간을 참고로 하여 지속저항성 품종을 선발하였다. 도열병에 대한 저항성 품종으로는 다양한 레이스에 침해되면서 개체당 병반수 20개 이내, 밭못자리검정에서는 평균 발병정도 5이하, 본답에서의 잎도열병은 병반면적율 0.5%이하, 이삭도열병 발생은 이병수율 5% 이내로 병발생이 비교적 적은 섬진벼, 팔공벼 및 동진벼를 선발하였고, 지속저항성 품종으로는 재배기간이 10년 이상 유지되면서 재배면적은 전체재배 면적의 20% 이상을 차지하고 있는 품종 중 장기간 동안 저항성을 발현하는 동진벼를 선발하였다.

• Research in Plant Disease
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• v.25 no.4
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• pp.164-172
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• 2019

Rice blast disease caused by Magnaporthe oryzae is the most important disease of rice in both South and North Korea. Cultivation of disease-resistant cultivar is the best way to prevent this notorious disease, but M. oryzae races have been continuously changed to adapt a new cultivar. Therefore, it is important to get the information about the race and avirulence genes of the pathogen for developing blast-resistant rice cultivar. Since the entrance of North Korea was prohibited, the information about the races of M. oryzae in North Korea border areas and South Korea was collected to get the information about the diversity of rice blast pathogen in North Korea. The disease occurrence on monogenic lines carrying single resistant gene was investigated in Jeonju, Suwon, Cheorwon, Goseong, and Baengnyeongdo in Korea, and Dandong in China. The monogenic lines in Jeonju and Suwon showed diverse ranges of the response, while those in Baengnyeongdo and Dandong showed relatively high resistant responses to rice blast. All the field isolates of M. oryzae were characterized for rice blast races by the Korean differential varieties and screened for known avirulence genes to determine the spatial distribution of avirulence genes and the population of M. oryzae.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.317-318
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• 2011

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.629-636
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• 2011

It has been suggested that buildings designed for strong ground motions will also have improved resistance to air blast loads. As an initial attempt to quantify this behavior, the responses of a ten story steel building, designed for the 1994 building code, with lateral resistance provided by perimeter moment frames, is considered. An analytical model of the building is developed and the magnitude and distribution of blast loads on the structure are estimated using available computer software that is based on empirical methods. To obtain the relationship between pressure, time duration, and standoff distance, these programs are used to obtain an accurate model of the air blast loading. A hemispherical surface burst for various explosive weights and standoff distances is considered for generating the air blast loading and determining the structural response. Linear and nonlinear analyses are conducted for these loadings. Air blast demands on the structure are compared to current seismic guidelines. These studies present the displacement responses, story drifts, demand/capacity ratio and inelastic demands for this structure.

• Korean Journal of Plant Resources
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• v.29 no.6
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• pp.658-669
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• 2016

Rice blast, caused by a fungus Magnaporthe oryzae, is one of the most devastating diseases of rice worldwide. Analyzing the valuable genetic resources is important in making progress towards blast resistance. Molecular screening of major rice blast resistance (R) genes was determined in 2,509 accessions of rice germplasm from different geographic regions of Asia and Europe using PCR based markers which showed linkage to twelve major blast R genes, Pik-p, Pi39, Pit, Pik-m, Pi-d(t)2, Pii, Pib, Pik, Pita, Pita/Pita-2, Pi5, and Piz-t. Out of 2,509 accessions, only two accessions had maximum nine blast resistance genes followed by eighteen accessions each with eight R genes. The polygenic combination of three genes was possessed by maximum number of accessions (824), while among others 48 accessions possessed seven genes, 119 accessions had six genes, 267 accessions had five genes, 487 accessions had four genes, 646 accessions had two genes, and 98 accessions had single R gene. The Pik-p gene appeared to be omnipresent and was detected in all germplasm. Furthermore, principal component analysis (PCA) indicated that Pita, Pita/Pita-2, Pi-d(t)2, Pib and Pit were the major genes responsible for resistance in the germplasm. The present investigation revealed that a set of 68 elite germplasm accessions would have a competitive edge over the current resistance donors being utilized in the breeding programs. Overall, these results might be useful to identify and incorporate the resistance genes from germplasm into elite cultivars through marker assisted selection in rice breeding.

• Korean Journal Plant Pathology
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• v.11 no.3
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• pp.238-244
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• 1995

Severity of panicle blast disease on the leading cultivars of rice was investigated at nine locations of Korea during summer in 1993 with frequent raining and low temperature conditions. Incidence of panicle blast was 26% on Jinmibyeo, 23% on Chuncheongbyeo and 40% on Odaebyeo. Race distribution of Pyricularia grisea was examined from 1993 to 1994. A total of 1,098 isolates of the fungus obtained from the blast nurseries and framers; fields were screened using Korean differential varieties. Twenty one races were identified in 1993 and 19 races in 1994. KI-181, KJ-103, KJ-104, KI-241 and KI-209 were identified as new races, and KJ-301 (15%), KJ-201 (13%), KJ-105 (12%) and KI-409 (12%) were major races during 1993 and 1994. Race KI-197, which has a wide spectrum of virulence on rice cultivars, was isolated in a ratio of 8.3% and evenly distributed in the whole country. Some of the major and newly identified races during 1993∼1994 were used for spray-inoculation on leading cultivars and differential varieties in a greenhouse. We found that most of the cultivars were resistant to the major races, KJ-301 and KI-409, but were very susceptible to the new races, KI-241, KI-209, KI-181 and KJ-103.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.10a
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• pp.15-20
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• 2005

Locations of silicon accumulation in rice leaves and its possible association with resistance to rice blast were investigated by analytical electron microscopy and atomic force microscopy. A blast-susceptible cultivar, Jinmi, and partially resistant cultivars, Hwaseong and Suwon345, were grown under a hydroponic culture system with modified Yoshida's nutrient solution. Electron-dense silicon layers were frequently found beneath the cuticle in epidermal cell walls of silicon-treated plants. Increasing levels of silicon were detected in the outer regions of epidermal cell walls. Silicon was present mainly in epidermal cell walls, middle lamella, and Intercellular spaces within subepidermal tissues. Furthermore, silicon was prevalent throughout the leaf surface with relatively small deposition on stomatal guard cells in silicon-treated plants. Force-distance curve measurements revealed relative hardness and smaller adhesion force in silicon-treated plants (18.65 uN) than control plants (28.39 uN). Moreover, force modulation microscopy showed higher mean height values of elastic Images In silicon-treated plants(1.26 V) than in control plants (0.44 V), implying the increased leaf hardness by silicon treatment. These results strongly suggest that silicon-induced cell wall fortification of rice leaves may be closely associated with enhanced host resistance to blast.