• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.142-146
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• 1996

옥수수 깜부기병균 Ustilago maydis 동포자를 풍건한 후 모래나 silica gel을 보존매체로 해서 4$^{\circ}C$나 그 이하 온도에서 24개월 두었을 때 동포자 생존율은 40~45%였다. 동포자는 28$^{\circ}C$ PDA상에서 쉽게 발아하여 많은 소생자를 형성하였다. U. maydis 동포자로부터 소생자 형성의 최적배지는 corn meal broth였고, carrot broth와 potato-dextrose broth의 순으로 좋았다. 소생자 형성에 가장 적합한 조건은 온도 28~3$0^{\circ}C$, pH5~7이었다. 소생자 형성은 암조건에서 보다 좋았다.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.147-149
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• 1996

Ustilago maydis의 소생자는 물한천배지에서 접종후 8시간 후에 98% 이상 발아하였다. PDA를 포함한 기타 영야배지에서의 발아율도 이와 비슷하였다. 소생자 발아에 가장 적당한 온도는 3$0^{\circ}C$였으며 $25^{\circ}C$나 35$^{\circ}C$순으로 양호하였으나 2$0^{\circ}C$나 그 이하의 저온에서는 발아율이 급격히 떨어졌다. 소생자는 pH 5~9의 범위에서 80%이상 발아하였으나 최적 pH는 6~7이었다. 광조사는 소생자 발아에 큰 영향을 미치지 못하였다. 소생자는 자유수분(RH 100%)하에서 24시간 후 81%가 발아하였으나 상대습도가 93%나 그 이하에서는 발아율이 19~34%였다. 이 실험결과는 소생자 발아에 가장 큰 영향을 미치는 환경요인은 온도와 습도였으며 우리나라 기후조건에서 소생자는 7~8월의 한여름철 장마기간 동안 왕성하게 발아할 수 있음을 뜻하고 있다.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.4
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• pp.770-783
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• 2015

Lately, high production rate welding processes for Al alloys, which are used as LNG FPSO cargo containment system material, have been developed to overcome the limit of installation and high rework rates. In particular, plasma-metal inert gas (MIG) hybrid (PMH) welding can be used to obtain a higher deposition rate and lower porosity, while facilitating a cleaning effect by preheating and post heating the wire and the base metal. However, an asymmetric undercut and a black-colored deposit are created on the surface of PMH weld in Al alloys. For controlling the surface defect formation, the wire feeding speed and nozzle diameter in the PMH weld was investigated through arc phenomena with high-speed imaging and metallurgical analysis.

• Research in Plant Disease
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• v.16 no.2
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• pp.183-190
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• 2010

During the period from 1999 to 2008, we surveyed the major diseases incidence of rice in Korea. Leaf blast showed 0.85% of the diseased leaf area in 2000 and then consistently decreased to 0.02% by 2008. However, panicle blast irregularly appeared by the years depending on weather conditions for disease development from heading to milk stage of rice. Diseased lesion height of sheath blight had the lowest (10.1%) incidence in 2001 and the highest (21.4%) incidence in 2007. A negative corelation ($r=-0.88^*$) was measured between diseased lesion height of sheat blight and sunshine hours from mid- to late August. In Chunbuk, Gyeongbuk, and Gyeongnam provinces, brown spot occurrence declined since 2001, however, in Chungnam, Jeonbuk, and Jeonnam provinces, it increased since 2005. False smut drastically decreased after showing the highest incidence of 7.59% in panicles in 2000. The correlation coefficient between diseased panicles of false smut and rainfall during the late August was calculated as $0.94^{**}$. Bacterial leaf blight severely increased in the chronically infested fields in Jeonnam, Jeonbuk, Gyeongnam, and Chungnam province since 2003.

• Research in Plant Disease
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• v.18 no.1
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• pp.24-28
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• 2012

The rice diseases occurring on the transgenic rice plant carrying protox gene (CPPO06) was assessed and compared with other varieties of rice such as Dongjin, Chucheong, Ilpeum, and Onnuri in the fields located in Cheongwon of Chungbuk, Suwon of Gyeunggi, and Gwangju of Chonnam. In the field of Cheongwon, the diseases such as blast, leaf spot, sheath blight and Fusarium blight were observed. False smut were observed only in the field of Suwon, where the ratio of diseased plants was 0.28% in CPPO06 and 0.37% in Onnuri, respectively. In the field of Gwangju, leaf spot caused by Cochlioborus miyabeanus was the most severely occurring disease among rice diseases mentioned above. Fusarium blight occurred in all the 3 fields, which were more severe in CPPO06 plants treated with or without oxadiazon as the herbicide. Except for Fusarium blight, there was no significant difference in the rice diseases as blast, leaf spot, sheath blight and false smut between CPPO06 and other rice varieties.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.60-60
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• 2015

Hybrid histidine kinase is a part of two-component system that is required for various stress responses and pathogenesis of pathogenic fungi. In the present study, Tco1, a homologue of human pathogen Cryptococcus neoformans Tco1 encoding a hybrid histidine kinase, was identified in corn smut pathogen Ustilago maydis by bioinformatic analysis. To explore the role of Tco1 in the virulence of U. maydis, mutants in which the tco1 gene was partially deleted were constructed by allelic exchange. The U. maydis tco1 mutants did show unaltered growth rate on axenic medium but were unable to produce conjugation tubes and develop fuzzy filaments, resulting in impaired mating of compatible strains. The expression levels of prf1, pra1, and mfa1 which are involved in the pheromone pathway significantly decreased in the tco1 mutants. In inoculation tests to host, the tco1 mutants showed significantly reduced ability in the production of anthocyanin pigments and tumor development on maize leaves. Overall, the combined results indicated that Tco1 plays important roles in sexual development and virulence of U. maydis by regulating the expression of the genes involved in the pheromone pathway.

• Proceedings of the Korean Society for Language and Information Conference
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• 2002.02a
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• pp.411-420
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• 2002

The left-associative grammar model (LAG) has been applied successfully to the morphologic and syntactic analysis of various european and asian languages. The algebraic definition of the LAG is very well suited for the application to natural language processing as it inherently obeys de Saussure's second law (de Saussure, 1913, p. 103) on the linear nature of language, which phrase-structure grammar (PSG) and categorial grammar (CG) do not. This paper describes the so-called Loom-LAGs (LLAG) -a specialization of LAGs for the analysis of natural language. Whereas the only means of language-independent abstraction in ordinary LAG is the principle of possible continuations, LLAGs introduce a set of more detailed language-independent generalizations that form the so-called loom of a Loom-LAG. Every LLAG uses the very smut loom and adds the language-specific information in the form of a declarative description of the language -much like an ancient mechanised Jacquard-loom would take a program-card providing the specific pattern for the cloth to be woven. The linguistic information is formulated declaratively in so-called syntax plans that describe the sequential structure of clauses and phrases. This approach introduces the explicit notion of phrases and sentence structure to LAG without violating de Saussure's second law iud without leaving the ground of the original algebraic definition of LAG, LLAGS can in fact be shown to be just a notational variant of LAG -but one that is much better suited for the manual development of syntax grammars for the robust analysis of free texts.

• The Plant Pathology Journal
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• v.27 no.1
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• pp.20-25
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• 2011

Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.130-137
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• 1983

A wide variety of pathogens are known io be seedborne, carried either as infectious mycelium internally or as contaminants on the seed coat. When seed is infected with a pathogen, the seed nay be rendered nonviable or it may remain viable but produce weak seedling. In some cases, the Infected seedling nay not be severely weakened, but nay serve as a source of primary inoculum within a community of plants. A recent problem nay be the dissemination of seedborne pathogens occurring as a result of the massive movements of seed, as a part of the 'Green revolution' Disease of great danger to agriculture may be introduced with seed from other parts of world. Seed treatment with organic mercury compounds in liquid form had become popular since about 1955. Organic mercury compounds contributed considerably to the increase in production of many crops and vegetables. In 1975, however, the use of organic mercury compound was forbidden because of doubts regarding their residual mammalian toxicity in agricultural products. Benomyl-thiram mixture, thiophanate methyl-;hiram mixture and TCMB have now been registered as seed disinfectants for the use of rice blast, brown spot and Bakanae disease. Oxathiinsthiram mixture has been registered as seed disinfectant for barley and wheat loose smut and leaf stripe of barley. Agricultural techniques have made such rapid progress that the nursery methods changed from the use of paddy nursery to box nursery designed for machine-transplanting. The spread of rice transplanting machines has caused increase of seedborne diseases. Among seedborne diseases, Bakanae disease has remarkably increased and causes much damage recently. In order to counter this trend, seed disinfectants must also be diversified. First, effective non-selective disinfectants need to be developed, and second, appropriate control methods always need to be prepared in parallel with the development of new techniques for cultivation.

• Korean Journal of Materials Research
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• v.25 no.9
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• pp.462-467
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• 2015

Pellicle is defined as a thin transparent film stretched over an aluminum (Al) frame that is glued on one side of a photomask. As semiconductor devices are pursuing higher levels of integration and higher resolution patterns, the cleaning of the Al flame surface is becoming a critical step because the contaminants on the Al flame can cause lithography exposure defects on the wafers. In order to remove these contaminants from the Al frame, a highly concentrated nitric acid ($HNO_3$) solution is used. However, it is difficult to fully remove them, which results in an increase in the Al surface roughness. In this paper, the pellicle frame cleaning is investigated using various cleaning solutions. When the mixture of sulfuric acid ($H_2SO_4$), hydrofluoric acid (HF), hydrogen peroxide ($H_2O_2$), and deionized water with ultrasonic is used, a high cleaning efficiency is achieved without $HNO_3$. Thus, this cleaning process is suitable for Al frame cleaning and it can also reduce the use of chemicals.