• 소성∙가공
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• 제25권6호
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• pp.353-358
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• 2016

Direct energy deposition (DED) is an additive manufacturing technique that involves the melting of metal powder with a high-powered laser beam and is used to build a variety of components. In recent year, it can be widely used in order to produce hard, wear resistant and/or corrosion resistant surface layers of metallic mechanical parts, such as dies and molds. For the purpose of the hardfacing to achieve high wear resistance and hardness, application of high speed steel (HSS) can be expected to improve the tool life. During the DED process using the high-carbon steel, however, defects (delamination or cracking) can be induced by rapid solidification of the molten powder. Thus, substrate preheating is generally adopted to reduce the deposition defect. While the substrate preheating ensures defect-free deposition, it is important to select the optimal preheating temperature since it also affects the microstructure evolution and mechanical properties. In this study, AISI M4 powder was deposited on the AISI 1045 substrate preheated at different temperatures (room temperature to $500^{\circ}C$). In addition, the micro-hardness distribution, cooling rates, and microstructures of the deposited layers were investigated in order to observe the influence of the substrate preheating on the mechanical and metallurgical properties.

• The Plant Pathology Journal
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• 제38권4호
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• pp.366-371
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• 2022

The white soybean cyst nematode Heterodera sojae, isolated from the roots of soybean in Korea, is widespread in most provinces of the country and has the potential to be as harmful to soybean as H. glycines. Determining the virulence phenotypes of H. sojae is essential to devising management strategies that use resistant cultivars. Consequently, virulence phenotypes of 15 H. sojae populations from Korea were determined on seven soybean lines and one susceptible check variety. Two different HS types were found to be present in Korea; the more common HS type 2.5.7, comprising 73.3% of the H. sojae populations and the less common HS type 0, constituting only 26.7% of the tested populations. Considering the high frequency of H. sojae adaptation to soybean indicator lines, the PI 88788 group may not be a possible source of resistance while PI 548402, PI 90763, PI 437654, and PI 89772 can be used as resistance sources for soybean breeding programs aimed at developing H. sojae-resistant soybean cultivars in Korea.

• 한국작물학회지
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• 제14권
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• pp.91-96
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• 1973

우리나라 대두의 단위면적당 생산량은 제외국에 비해 낮은 편이며 그 원인은 여러 가지로 생각할 수 있으나 단시일내에 기존품종으로서 생산량을 높이는데 대두 초형에 따르는 재식방법의 개선이 중요하다고 여겨져 중부지방에서의 밀식적응대두형과 밀식정도의 구명을 위해 본 시험이 수행되었다. 본 시험에서는 모형과 각종 형질이 서로 상이한 품종인 장단백목, 충북백, Clark 등 3개 품종이 공시되었으며 휴폭을 세구로 그리고 주간거리를 세세구로 한 3반복으로서 시험하였다. 주당 분지수와 협수는 밀식에 따라 감소되었으나 동일한 밀도에서는 Clark에서 보다 충북백과 장단백목에서 더 많은 분지수를 가지고 있었으며, 협수에 관해서는 휴폭과 주간거리에 유의한 수준의 상호작용이 있었다. 절수는 품종간에 차이가 현저하였으며 휴폭에 의해서는 전혀 변화가 없었으며 주간거리가 커짐에 따라 Clark에서 약간 증가하였다. 간장도 주간거리에 관해서만 유의차가 현저하였으나 절수의 증가와는 관계없이 도장에 기인하였다. 도복성에는 Clark가 가장 강했으며 이는 이 품종 주경의 탄력성 때문인 것으로 여겨졌다. 밀식조건하에서는 다지성이고 광엽성인 재래품종들보다 절수가 많고 초장이 큰 도입품종 Clark가 공시된 3개 품종중 가장 수량이 많았으며 밀식재배용으로의 가장 알맞은 초형임이 명확하였고 파종은 재래식 점파보다는 조파로 밀식함이 노력이 절약되고 단위면적당 수량도 현저히 증가될 것이다.

• 한국초지조사료학회지
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• 제37권1호
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• pp.44-49
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• 2017

본 시험은 중부지역에서 사료용 옥수수의 검은줄오갈병 발생이 조사료 생산성 에 미치는 영향을 조사하기 위하여 2006년부터 2008년까지 충청남도 천안에서 수행되었다. 사료용 옥수수의 공시품종은 국내에서 재배되고 있는 10품종으로 하였고, 재배방법은 4월 하순에 파종하는 1모작 재배와 5월 중하순에 파종하는 2모작 재배로 나누어 재배하였으며, 품종별 검은줄오갈병의 발생률과 수량성을 조사하였다. 우리나라 중부지역에서 사료용 옥수수의 품종별 검은줄오갈병의 발생률은 차이가 있었다(p<0.05). 검은줄오갈병에 강한 품종은 광안옥, P3156, 광평옥 및 P3394 품종이었고 약한 품종은 'NC+7117', '수원19호' 'DK697' 및 'GW6959' 품종이었다. 검은줄오갈병 발생에 따른 사료용 옥수수의 조사료 건물수량은 품종 간에 차이가 있었으며(p<0.05), 검은줄오갈병 발생이 많았던 수원 19호와 GW6959 품종의 건물수량이 검은줄오갈병 발생이 적었던 광평옥과 P3156 품종보다 20% 정도 적었다. 옥수수의 품종별 암이삭 비율은 검은줄오갈병 발생이 많았던 NC+7117 및 GW6959 품종이 약 29%로 가장 낮았고 검은줄오갈병의 발생이 적었던 광평옥, P3394 및 P3156 품종에서는 각각 34.0, 38.7 및 36.4%으로 높은 경향이었다. 따라서 우리나라 중부지역에서 사료용 옥수수를 재배할 때는 검은줄오갈병에 강한 품종을 선택하고 파종시기의 조절이 매우 중요하다 할 것이다.

• 한국작물학회지
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• 제26권2호
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• pp.137-145
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• 1981

1979년 수원 작물시험장 포장에서 도열병에 심하게 이병된 ‘노풍’ 품종의 이병엽(짚)을 수거하여 도열병에 대한 품종 저항성을 유묘 검정하는데 접종원으로 사용하였다. 접종시외 온도 및 Water Stress 의 환경조건을 달리해 줌으로써, 공시품종의 도열병에 대한 반응에 미치는 영향을 조사하였다. 1. 이병엽(짚)을 접종원으로 사용하여 도열병에 대한 품종저항성을 검정하는 방법은 비교적 많은 품종 및 계통들을 일시에 조사할 경우 편리하게 이용될 수 있었다. 2. 고온조건(25^\circ C \sim 35^\circ C)에서보다 저온조건(15^\circ C \sim 28^\circ C)에서 공시품종들의 도열병 발병이 비교적 더 많았다. 그러나 온도에 따른 도열병 반응의 차이는 품종에 따라서 매우 상이하였다. Indica-Japonica hybrid 품종들은 대개 고온에서 발병이 더 급격하고 많았지만, Japonica 품종들은 대개 저온에서 발병이 많은 편이었다. 3. Water stress를 받지 않은 환경조건에서보다 일시적인 Water stress를 받은 환경수건에서, 공시품종들의 도열병 발병이 더 많았다. 품종의 Water stress에 따른 도열병 반응의 차이는 온도에 따른 품종간의 차이(품종과 온도의 interaction)에 비해서 적은 편이었다. 4. 저항성 품종들(Tetep, Zenith, Toride 1, 수원 288호 등)의 도열병에 대한 반응은 환경조건의 영향을 거의 받지 많았지만 중도저항성 품종들(신002, Kanto 51, 흑조, 아끼바레 등)은 환경조건의 영향을 많이 받았다. 이병성 품종들은 어떤 환경조건에서도 발병이 많았다. 5. 접종원으로 사용된 이병엽의 병원성은 Pi-\alpha 품종(‘애지욱’, ‘Ca1oro’) 및 Pi-$textsc{k}$ 품종(‘Kanto 51’), 통일계 신품종에 강한 병원성을 나타내었으나, ‘신002’, ‘Fukunishiki’, ‘진흥’ 등의 품종에 중도저항성 반응을 보였고, ‘농백’에는 병원성이 없었다. 국제판별 품종이나 일본신판별 품종으로써는 정확한 race 유별이 불가능했다. 각 환경수건에 따라 판별품종의 반응이 약관씩 다르게 나타났지만 대체로 blast nursery 성적과는 반응이 비슷하였다. 6. 정도 저항성 및 이병성으로 나타난 ‘Kanto 51’, ‘Yashiromochi’, ‘Ishikari-shiroke’ 등의 품종들에서는 접확후 병반형 및 병반수의 변이가 매우 심하였다. 급성형(이병성, PG형) 병반을 많이 형성하는 품종들(‘애지욱’, ‘Caloro’, ‘Norin 6’ 등)은 고도의 이병성이었고 저항성 품종들은 대개 병반이 없거나 저항성 병반(hypersensitivity 반응, b 혹은 bg 형)을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제29권12호
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• pp.1904-1915
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• 2019

Resistant starch (RS) is metabolized by gut microbiota and involved in the production of short-chain fatty acids, which are related to a variety of physiological and health effects. Therefore, the availability of RS as a prebiotic is a topic of interest, and research on gut bacteria that can decompose RS is also important. The objectives in this study were 1) to isolate a human gut bacterium having strong degradation activity on non-gelatinized RS, 2) to characterize its RS-degrading characteristics, and 3) to investigate its probiotic effects, including a growth stimulation effect on other gut bacteria and an immunomodulatory effect. Bifidobacterium adolescentis P2P3 showing very strong RS granule utilization activity was isolated. It can attach to RS granules and form them into clusters. It also utilizes high-amylose corn starch granules up to 63.3%, and efficiently decomposes other various types of commercial RS without gelatinization. In a coculture experiment, Bacteroides thetaiotaomicron ATCC 29148, isolated from human feces, was able to grow using carbon sources generated from RS granules by B. adolescentis P2P3. In addition, B. adolescentis P2P3 demonstrated the ability to stimulate secretion of Th1 type cytokines from mouse macrophages in vitro that was not shown in other B. adolescentis. These results suggested that B. adolescentis P2P3 is a useful probiotic candidate, having immunomodulatory activity as well as the ability to feed other gut bacteria using RS as a prebiotic.

• 한국육종학회지
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• 제41권2호
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• pp.92-100
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• 2009

To investigate the mutagenecity of sodium azide (SA) and to select mutants having various agronomic characteristics in rice (Oryza sativa L. ssp. japonica), dry seeds of rice variety 'Suweon 472' were treated with 0, 0.5, 1.0, 2.0, and 4.0 mM SA solutions prepared in 0.1 M phosphate buffer (pH 3.0). Germination rate, seedling height and sterility were investigated in $M_1$ generation and chlorophyll mutations were observed in $M_3$ generation. Germination rate and seedling height decreased as the increase of SA concentration in $M_1$ generation, the maximum seed sterility (40.8%) was found at 4.0 mM SA concentration. Chlorophyll mutants were occurred in $M_3$ generation and the frequency calculated on a line basis was 13.5% at the same treatment. Many kinds of mutations for morphological and agronomic characters were observed and mutations with short culm and glabrous leaf were frequently found in $M_3$ generation. Interestingly, five mutant lines resistant to blast or bacterial blight (BB) were selected and evaluated with several isolates in $M_3$ generation although Suweon 472 has been known to be susceptible to blast and BB. These mutants showed all resistance to seven isolates of blast and a total of 76 lines among 2,567 lines evaluated showed resistant to race K1 of bacterial blight. Two mutant lines (440172 and 41272) showed different reaction to BB isolates from the other resistant mutants. A few kinds of endosperm mutants were also identified and most of them were waxy mutants.

• The Plant Pathology Journal
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• 제38권6호
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• pp.572-582
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• 2022

Sheath blight disease caused by the necrotrophic, soilborne pathogen Rhizoctonia solani Kuhn, is the global threat to rice production. Lack of reliable stable resistance sources in rice germplasm pool for sheath blight has made resistance breeding a very difficult task. In the current study, 101 rice landraces were screened against R. solani under artificial epiphytotics and identified six moderately resistant landraces, Jigguvaratiga, Honasu, Jeer Sali, Jeeraga-2, BiliKagga, and Medini Sannabatta with relative lesion height (RLH) range of 21-30%. Landrace Jigguvaratiga with consistent and better level of resistance (21% RLH) than resistant check Tetep (RLH 28%) was used to develop mapping population. DNA markers associated with ShB resistance were identified in F₂ mapping population developed from Jigguvaratiga × BPT5204 (susceptible variety) using bulk segregant analysis. Among 56 parental polymorphic markers, RM5556, RM6208, and RM7 were polymorphic between the bulks. Single marker analysis indicated the significant association of ShB with RM5556 and RM6208 with phenotypic variance (R²) of 28.29 and 20.06%, respectively. Co-segregation analysis confirmed the strong association of RM5556 and RM6208 located on chromosome 8 for ShB trait. This is the first report on association of RM6208 marker for ShB resistance. In silico analysis revealed that RM6208 loci resides the stearoyl ACP desaturases protein, which is involved in defense mechanism against plant pathogens. RM5556 loci resides a protein, with unknown function. The putative candidate genes or quantitative trait locus harbouring at the marker interval of RM5556 and RM6208 can be further used to develop ShB resistant varieties using molecular breeding approaches.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 추계국제학술대회
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• pp.64-64
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• 2020

Bakanae disease, caused by several Fusarium species, imposes serious limitations to the productivity of rice across the globe. The incidence of this disease has been shown to increase, particularly in major rice-growing countries. Thus, the use of high resistant rice cultivars offers a comparative advantage, such as being cost effective, and could be preferred to the use of fungicides. In this research, we used a tropical japonica rice variety, Zenith, a bakanae disease resistant line selected as donor parent. A RIL population (F_8:9) composed of 180 lines generated from a cross between Ilpum and Zenith was used. In primary mapping, a QTL was detected on the short arm of chromosome 1, covering about 3.5 Mb region flanked by RM1331 and RM3530 markers. The resistance QTL, qBK1^Z, explained about 30.93% of the total phenotype variation (PVE, logarith of the odds (LOD) of 13.43). Location of qBK1^Z was further narrowed down to 730 kb through fine mapping using additional RM markers, including those previously reported and developed by Sid markers. Furthermore, there is a growing need to improving resistance to bakanae disease and promoting breeding efficiency using MAS from qBK1^Z region. The new QTL, qBK1^Z, developed by the current study is expected to be used as foundation to promoting breeding efficiency with an enhanced resistance against bakanae disease. Moreover, this study provides useful information for developing resistant rice lines carrying single or multiple major QTLs using gene pyramiding approach and marker-assisted breeding.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제30권2호
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• pp.15-22
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• 2024

Purpose: In general, cross-infection caused by bacteria occurs more in hospitals than in local communities. In most cases, infectious diseases spread through contact transmission (direct contact, indirect contact). This study tries to examine which places are most likely to detect infections bacteria and what materials should be used to effectively suppress the spread of infectious bacteria. Methods: Domestic and international literature have been reviewed to determine which bacteria are common and spread in which places. At the same time, antibacterial experiments for several finishing materials are performed to determine the survival period of bacteria for each material. The experiment is conducted mainly on antibiotic-resistant bacteria (MRSA, CRE, etc.) that have a high mortality rate and are very contagious. Results: MRSA has a high incidence in many hospital departments with surgery or immunocompromised patients, such as the elderly, organ transplant patients, and hemodialysis patients. There are experimental results that MRSA dies early in ceramics or silk wallpaper. CRE has a high incidence in hospital departments where there are many patients who are prone to bacteria entering the body directly, such as ventilator patients or critically ill patients with surgical wounds. There are experimental results that CRE dies early in silk wallpaper. In addition, bacteria die on the surface for a variety of reasons. Most MRSA and CRE develop in patients with impaired immunity or surgery, and rapidly die in copper or materials with antibacterial properties. Implications: If finishing materials surface with the ability to kill specific bacteria is used in the place where a large number of specific bacteria are detected, the spread of infectious diseases can be effectively controlled.