• 한국산림과학회지
• /
• 제86권2호
• /
• pp.251-258
• /
• 1997

칠엽수과(科) 2속(屬)의 20종(種) 1변종(變種)에 대한 화분 형태를 광학현미경, 주사형전자현미경 그리고 투과형전자 현미경을 이용하여 관찰하였다. 화분립은 단립, 장구형 내지 아장구형, 등극성, 방사성 대칭, 발아구는 3공구형 혹은 3구형이며 내공구는 원형 또는 횡장형이다. 표면무늬는 유선상 혹은 자상이며, 골은 다양한 방향이다. 칠엽수과(科)의 화분을 발아구의 형태와 표면무늬에 의하여 hipppocastanum형, indica형 그리고 punduana형의 3가지 화분형으로 나눌 수 있었다.

• Mycobiology
• /
• 제45권2호
• /
• pp.114-118
• /
• 2017

In September 2013 and 2014, a significant number of kenaf plants showing symptoms of leaf spots with approximately 50% incidence were found in experimental plots in Iksan and Namwon, Korea. Leaf spots were circular to irregular, more or less vein-limited, reaching to 10 mm in diameter. The spots were initially uniformly brown to reddish brown, turning pale brown with a purplish margin and showing grayish patches on the lesion due to heavy fructification. The causative agent of the leaf spot disease was identified as Cercospora malayensis. The pathogenicity test was conducted with similar results, which fulfilled Koch's postulates. This is the first report of C. malayensis infection of kenaf in Korea.

• 식물병과 농업
• /
• 제5권1호
• /
• pp.1-7
• /
• 1999

The grain rot of caused by Bukholderia glumae was fist reported in japan in 1955 and then reported in other countries as well as in Korea in 1986. The pathogen causes both seedling and grain rot of rice but it cannot attack any other parts of adult rice plant. Bacterial colonies grow slowly, and are circular and greyish white. The causal bacterium is Gram-negative and rod shape with 1-3 polar flagella, and produce a diffusible yellow-greenish nonfluorescent pigment on King's medium B. Biochemical characteristics such as negative in arginine dehydrolase, oxidase reaction and nitrate reduction and positive in lecithinase, and the utilization of L-arginine and inositol are useful in differentiation of this from other nonfluorescent bacteria pathogenic to rice. This pathogenic bacterium had belonged to the genus of Pseudomonas but recently was transferred to the new genus Burkholderia on the basis of physiological characteristics and DNA-DNA hybridization data. However, other characteristics such as colony heterogenicity or colonial variation after subcultures, phytotoxin, secreting antibiotics, and relationship between yellow greenish pigment production and pathogenicity need to be clarified more. To develop an effective control strategy for this disease, understanding of detailed life cycle of the disease and critical environmental factors affecting disease development is prerequisite. Although 5,435 ha of rice paddy in Korea was infested during 1998, there is no exact estimation of yield losses and distribution of the pathogen. The review will focus on recent progress on the understanding of the bacteriological and ecological characteristics of the causal bacterium and control means of the disease.

• 식물병과 농업
• /
• 제5권2호
• /
• pp.69-76
• /
• 1999

Acidovorax avenae subsp. avenae is the causal pathogen of several hosts including oats corn foxtail millet wheatgrass sugarcane and rice. The pathogen is a seedborne pathogen of rice and known to occur widely in rice growing countries. The pathogen cause inhibition of germination brown stripe on the leaf curling of the leaf sheath and abnormal elongation of the mesocotyl of irce. Bacterial colonies grow slowly and are convex circular and creamy with tan to brown center. The causal baterium is Gram-negative and rod shape with a single polar flagellum Nonfluorescence poly-$\beta$-hydroxybutyrate accumulation and precipitate formation around the colony on the medium are useful in the differentiation of this bacterium from other subspecies of A. avenae as well as nonfluorescent bacteria pathogenic to rice. This bacterium has belonged to the genus of Psdeudomonas but recently was transferred to the new genus Acidovorax on the basis of bacteriological and molecular biological data. However the difference of biochemical characteristics protein profile of the cell and host range among strains should be more clarified. To develop an effective control strategy for this disease understanding of detailed life cycle of the disease ritical environmental factors affecting disease development on each host and relationship to grain discoloration of rice are prerequisite. Although the affected area has been world-widely reported there is on recent progress on the understanding of the bacteriological and ecological characteristics of the causal bacterium and control means of the disease.

• Journal of the Korean Wood Science and Technology
• /
• 제26권1호
• /
• pp.38-50
• /
• 1998

Laser cutting tests were conducted to investigate the laser cutting characteristics of solid woods such as 25mm-thick white oak(Quercus acutissima) and maple(Acer mono), and wood-based panels such as 15mm-thick medium density fiberboard and particleboard. Test variables were laser power, cutting speed, grain direction, and moisture content. Specific cutting energy was measured and the qualities of cut surface were estimated in constant laser power. Specific cutting energy of white oak was larger than that of maple, and specific cutting energy of medium density fiberboard was smaller than that of particleboard. For both white oak and maple, specific cutting energy of green wood was smaller than that of air-dried wood because weight loss of moisture evaporation in green wood was larger than that in air-dried wood. In laser-cut surface, wood cells were not deformed and damaged, but in circular saw-cut surface fibers were pushed out and cut, and wood cells were deformed severely. However, mechanical surface roughness of saw-cut surface was smoother than that of laser-cut surface because of the existence of undeformed cell cavity in laser-cut surface.

• 한국축산시설환경학회지
• /
• 제20권4호
• /
• pp.155-160
• /
• 2014

This study was researched for use by data for the improvement of ventilation system of optimum environmental control systems. The ventilation system for windowless swine housing was installed negative pressure system that circular pipe duct for inlet was installed on the ceiling and axial flow fan for exhaust was installed on the sidewall. The temperatures in the pen was measured using infrared thermography camera and thermocouple with data-logger. The temperature measurement points was selected by infrared thermography camera is alley (G), inlet (A), front-upper (B), front-lower (C), rear-upper (D), rear-lower (E), forward fan (F). The temperature measured at those selected points for temperature distribution was $28^{\circ}C$ that was maintained setting temperature in suitably. The temperature deviations of F point and A~E points in windowless swine housing was less then average $0.5^{\circ}C$. The result of air velocity of measured points was suitable to the breeding of pigs.

• 대한수의학회지
• /
• 제33권4호
• /
• pp.617-622
• /
• 1993

The preliminary studies on the localization of adrenoceptors were performed on smooth muscle strips of bovine esophageal groove. The mechanical activity of the muscle strip was recorded isometrically in vitro.w In the bottom circular muscle strips. the excitatory ${\alpha}-adrenergic$ responses were not blocked by tetrodotoxin$(2.1{\times}10^{-6}M)$ and denervation which was carried by cold storage of strips for 48 hrs in Tyrode's solution at $5-6{^{\circ}C}$ without oxygen supply. These excitatory ${\alpha}-adrenergic$ responses were partially blocked by atropine. In the lip longitudinal muscle strips, the inhibitory${\beta}-adrenergic$ responses were not blocked by pretreatment of tetrodotoxin and atropine. The results suggest that ${\beta}-adrenergic$ receptors mediating relaxations are located on the postsynaptic smooth muscle cells, whereas ${\beta}-adrenergic$ receptors mediating contractions are located both in the smooth muscle cells and in the cholinergic neurones.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제17권11호
• /
• pp.3083-3098
• /
• 2023

As demands for efficient and echo-friendly production of marine products increase, smart aquaculture based on information and communication technology (ICT) has become a promising trend. The smart aquaculture is expected to control fundamental farm environment variables including water temperature and dissolved oxygen (DO) levels with less human intervention. A recirculating aquaculture system (RAS) is required for the smart aquaculture which utilizes a purification tank to reuse water drained from the water tank while blocking the external environment. Elaborate water treatment should be considered to properly operate RAS. However, analyzing the water treatment performance is a challenging issue because fish farm circumstance continuously changes and recursively affects water fluidity. To handle this issue, we introduce computational fluid dynamics (CFD) aided water treatment analysis including water fluidity and the solid particles removal efficiency. We adopt RAS parameters widely used in the real aquaculture field to better reflect the real situation. The simulation results provide several indicators for users to check performance metrics when planning to select appropriate RAS without actually using it which costs a lot to operate.

• 농업과학연구
• /
• 제25권1호
• /
• pp.97-106
• /
• 1998

본 연구는 현재 산사태 대책수립에 많이 이용되고 있는 원호활동 해석방법의 문제점을 규명하기 위하여 실시되었으며, 여기서 얻어진 결과를 요약하면 다음과 같다. 1. 40개의 모델사면을 지층에 따라 활동면을 분석해 본 결과, 풍화토와 풍화암의 경계 부분이 다른 부분에 비하여 활동이 일어날 가능성이 높은 것으로 나타났다. 2. 우리나라에서 발생하는 산사태의 대부분이 깊이 2m를 전후로 하여 토층의 경계부근등 주로 불연속면을 따라 발생하기 때문에 절취사변에 대한 산사태의 안정해석을 할때, 무한사면해석을 우선 고려하는 것이 안전한 설계가 될 것으로 판단된다. 3. 사면경사가 일정한 상태에서 사면길이만을 변화 시켰을 경우, 원호활동사면인 경우는 토층이 얕고 사면길이가 짧을수록 안전하였으나 무한사면인 경우는 사면길이에 관계없이 최소안전율은 동일하였다. 4. 우리나라 산사태의 대부분을 차지하는 사면경사 $30^{\circ}$의 조건으로 원호활동해석과 무한활동해석으로 분석한 결과, 상호간의 최소안전율의 차이가 많으며 원호활동해석 방법은 무한활동해석에 비해 과다하게 안전측으로 나타났다.

• 식물병연구
• /
• 제15권3호
• /
• pp.209-216
• /
• 2009

2005년 6월부터 2008년 5월까지 전북 장수, 전주 및 전남 장성 등에서 흰가루병에 걸린 44종의 기주식물을 채집하였으며, 12종의 식물에서 Ampelomyces의 중복기생이 확인되었다. Ampelomyces의 병자각의 형태는 대부분이 원형 또는 타원형이었으며, 같은 기주식물에서도 그 크기가 다양했고, 병자각의 색은 옅은 갈색에서 진한 갈색이었다. 봉선화, 고들빼기, 쥬키니호박, 삼잎국화 로부터 Ampelomyces 균을 분리하였고, 이 중 실험에 적합한 Ampelomyces 균주 12개를 최종 선발하였다. 선발된 12균주의 배양적 특성 및 영양요구를 조사한 결과 Malt extract agar에서 가장 생육이 좋았다. 삼투압이 Ampelomyces의 포자발아에 미치는 영향에 대해 조사한 결과 Czapek dox agar에 질소원인 NaCl 0.15M을 첨가한 배지에서 포자발아율이 가장 높았다. Ampelomyces 분리 균의 길항 효과를 실험한 결과 다른 식물 병원균에 대한 항균효과가 있었다. 분리한 균주는 식물체에 이상이 생기거나 병이 발생하지 않아서 Ampelomyces는 식물에 병원성을 가지고 있지 않다는 사실을 알 수 있었다. 본 실험에 주로 사용된 균주 BSLAH16의 rDNA ITS 영역에 대한 염기서열을 분석한 결과 A. quisqualis 또는 Ampelomyces sp.로 동정 되었다.