• Mycobiology
• /
• 제38권2호
• /
• pp.122-127
• /
• 2010

Different strains of mold were screened for the production of high quality Korean traditional rice wine with anti-hypertension and good acceptability. We isolated 867 nuruk mold strains and selected 24 for further study based on measurement of amylase activity. Among them, mold No. 17 showed high ethanol production upon fermentation with Saccharomyces cerevisiae as well as anti-hypertensive properties. The No. 17 strain was therefore selected as the functional mold and later identified as Rhizopus stolonifer based on molecular biological characteristics. Optimal fermentation conditions for the brewing of anti-hypertensive traditional rice wine comprised the addition of R. stolonifer No. 17 koji at a concentration of 35 sp/g and a fermentation period of 10 days at $25^{\circ}C$ using S. cerevisiae.

• Design & Manufacturing
• /
• 제8권1호
• /
• pp.40-44
• /
• 2014

As a rotating machine element, plastic gears are more and more widely used in such as industrial machine element, since plastic gear is lighter, higher wear-resistance, and higher vibration absorbing ability than metal gears. When operating plastic parts, tooth breakage and fatigue life shortened due to increasing number of applying load and tooth flank temperature rising, such that accuracy of plastic gears is divided from allowable range to cause vibration and noise. On this study, a internal plastic gears are developed which improved the filling balance molding process by a new injection mold structure. The new mold structure called HR3P(hot runner type 3plate mold). As the result from this studies, we obtained a very accurate roundness internal gears by using design of experiment.

• 한국생산제조학회지
• /
• 제20권4호
• /
• pp.478-483
• /
• 2011

Cast mold has low wear-resistance comparing with other alloyed molds which result in lower production rate and high cost of products. Recently, various weld methods are being applied to increase the wear-resistance of molds and to extend mold life. Among them, nickel alloy weld process increases the hardness irrelevant to its machinability and creates very uniform structures. In addition, it causes better wear-resistance and reduces shrinkage defects. In this paper, we analyze the mold surface cracks welded by nickel alloy and propose the methods to improve the mold surface and its wear-resistance. It has been found that nickel alloy weld does not affect the inside crack of mold but has an influence on the surface crack seriously. Results show that the start and growth of fatigue cracks have been delayed about 3 times and reduced approximately 75%, respectively, and the mold surface cracks are decreased about 5.7 times.

• Mycobiology
• /
• 제35권4호
• /
• pp.180-185
• /
• 2007

Grape fruits with blue mold symptoms were collected from house storages in different locations in Korea and were investigated for their association with Penicillium species. A total of 12 isolates of Penicillium were isolated from the collected fruits. Based on morphological and cultural characteristics and ${\beta}-tublin$ gene sequence data analysis, they were identified as P. bialowiezense, P. citrinum, P. echinulatum, P. expansum, P. solitum and unidentified Penicillium species. P. solitum was the predominant followed by P. expansum. P. bialowiezense and P. echinulatum were newly recorded in Korea. ${\beta}-Tubulin$ gene sequences could be used to distinguish each species of Penicillium and the molecular groups were correlated well with the morphological species. The unidentified species was supposed to be a new species, not previously reported in literature.

• The Plant Pathology Journal
• /
• 제22권3호
• /
• pp.283-288
• /
• 2006

Trichoderma harzianum YC459 (Th 459), isolated from sawdust compost, was effective in controlling cucumber and tomato gray mold caused by Botrytis cinerea under controlled and plastic film tunnel conditions. A water suspension of the wettable powder formulation of Th 459 significantly $(P\leq0.05)$ reduced the severity of cucumber gray mold by foliar spraying at all tested concentrations from $10^5\;to\;10^8$ colony forming unit (cfu)/ml in repeated experiments. The control efficacy was maintained at least seven days with the average control value of 70% in cucumber pot tests. Mixing one to eight grams of the granular formulation ($10^8cfu/g$ dry weight) of Th 459 into one liter nursery potting mix at seeding also significantly $(P\leq0.05)$ reduced the severity of cucumber gray mold by suppression of lesion formation three weeks after treatment. Application of mixing granular formulation at seeding in combination with foliar spraying during cultivation provided a more significant reduction $(P\leq0.05)$ of cucumber gray mold than granule mixing or leaf spray alone. The foliar spraying of the formulated wettable powder of Th 459 significantly $(P\leq0.05)$ reduced the infection of tomato fruits by B. cinerea as effective as the chemical fungicide, dichlofluanid, in three plastic film tunnel experiment trials. It is suggested that effective control of gray mold of cucumber and tomato can be provided by both treatment of Th 459 into potting mix and foliar spray through induction of systemic resistance and direct inhibition of the pathogen.

• 농약과학회지
• /
• 제19권3호
• /
• pp.295-300
• /
• 2015

국내 딸기는 현재 홍콩, 싱가포르 및 동남아시아 지역으로 수출량이 증대되고 있는 가운데 유통과정에서 환경조건에 따라 품질에 손상이 크게 발생하고 있다. 주로 수출딸기에 품질손상을 일으키는 잿빛곰팡이병은 다른 국가로 이동하는 동안 혹은 수입국에서 소비자에게 판매되기까지의 기간 동안 발생하고 있다. 본 연구는 수출딸기 선별장 공기중 부유중인 잿빛곰팡이병원균의 밀도와 저장중 발병률에 관한 상관관계를 규명하기 위하여 수행되었다. 공기중 병원균의 밀도가 증가함에 따라 저온 저장중 병 발생율이 최대 16%로 나타났다. 상온저장의 경우 상대적으로 공기중 병원균의 밀도가 낮게 조사된 12월 말부터 발병율 100%가 관찰 되었다. 본 연구결과, 선별장의 잿빛곰팡이 병원균 밀도와 저장중 병발생의 상관관계가 구명되었다.

• 한국균학회지
• /
• 제45권3호
• /
• pp.251-257
• /
• 2017

최근 경북 포항의 산딸기 재배지역에서 잿빛곰팡이병 증상이 발생하였다. 초기에는 잎의 가장자리나 과경 부위에 갈색 반점이 나타나며 병이 진전되면 병반 부위가 확대되고 수침상으로 물러지면서 표면이 회색 곰팡이로 덮이는 것이 관찰되었다. 이러한 증상이 발생한 잎으로부터 병원균을 분리하고 균학적 특성을 조사하고 계통학적 분석을 수행하였다. 분석 결과 산딸기에서 발생한 잿빛곰팡이병의 병원균은 Botrytis cinerea로 확인되었으며, 건전한 산딸기 식물체를 대상으로 접종실험 한 결과 산딸기에 대한 병원성을 확인하였다. 지금까지 국내에서 B. cinerea에 의한 산딸기 잿빛곰팡이병이 보고되지 않았으므로 본 연구결과를 바탕으로 이 병을 국내 최초로 보고한다.

• Design & Manufacturing
• /
• 제13권2호
• /
• pp.44-48
• /
• 2019

Motor core products are used as materials for electrical steel sheets and cold-rolled steel sheets according to the performance of motors. The cemented carbide material of the mold punch applied to the motor core material causes many troubles due to abrasion and burr problem. The selection of these materials has a great effect on the production life, mass production, product quality as well as mold life. The cemented carbide applied to the products of the motor core is recognized as a very important part. In this study, cold rolled steel sheet was applied to motor core SCP-1 steel 1.0mm, and The effects of abrasion and punching oil on the shear process were investigated for the selection of cemented carbide. Experiments were conducted to select and apply cemented carbide only for the motor core punch optimized for cold rolled steel. The results showed that the cemented carbide material of $CDK3^{***}$ produced the least wear and burrs.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 Handout for 2000 Inter. Machine Tool Technical Seminar
• /
• pp.19-27
• /
• 2000

High speed machining (HSM), specifically end milling and ball end cutting, is attracting interest in the die/mold or aerospace industries for the machining of complex 3D surfaces. HSM of difficult-to-cut materials such as die/mold steels, titanium alloys or nickel based superalloys generates the concentrated thermal/frictional damage at the cutting edge of the tool and rapidly decreases the tool life. Following a brief introduction on HSM and reated aerospace or die/mold work, the paper reviews published data on the effect of cutter/workpiece orientation and cutting environments on tool performance. First, experimental work is detailed on the effect of cutter orientation on tool life, cutting forces, chip formation, specific force and workpiece surface roughness. Cutting was performed using 8 mm diameter PVD coated solid carbide cutters with the workpiece mounted at an angle of 45 degree from the cutter axis. A horizontal downwards cutting orientation proveded the best tool life with cut lengths ∼50% longer than for all other directions (horizontal upwards, vertical downwards, vertical upwards). Second, the cutting environments were investigated for dry, flood coolant, and compressed chilly air coolant cutting. The experiments were performed for various hardened materials and various coated tools. The results show that the cutting environment using compressed cilly air coolant provided better tool life than the flood coolant or the dry.

• 한국금형공학회:학술대회논문집
• /
• 한국금형공학회 2008년도 하계 학술대회
• /
• pp.129-133
• /
• 2008

As a rotating machine element, plastic gears are more and more widely used in such as industrial machine element, since plastic gear is lighter, higher wear-resistance, and higher vibration absorbing ability than metal gears. When operating plastic parts, tooth breakage and fatigue life shortened due to increasing number of applying load and tooth flank temperature rising, such that accuracy of plastic gears is divided from allowable range to cause vibration and noise. On this study, a internal plastic gears are developed which improved the filling balance molding process by a new injection mold structure. The new mold structure called HR3P(hot runner type 3plate mold). As the result from this studies, we obtained a very accurate roundness internal gears by using design of experiment.