• 한국재료학회지
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• 제10권6호
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• pp.415-421
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• 2000

실리카 바인더 함량이 지르콘 쉘 주형의 기계적 특성에 미치는 영향을 고찰하였다. 실리카 졸/지르콘 함량비 $R_w$는 0.18~0.43 범위에서 변화시켰으며, 주형의 소결온도는 $871^{\circ}C~1400^{\circ}C$ 범위에서 변화시켰다. 생형의 상온강도는 실리카 졸/지르콘 함량비 $R_w$에 비례하여 증가하였다. 소결온도가 $1300^{\circ}C$ 이하인 경우, $R_w$가 증가함에 따라 소결된 주형의 상온강도와 치밀화는 증가하였다. 그러나 $R_w$가 0.43이고 $1400^{\circ}C$에서 3시간 동안 소결시킨 경우 주형의 상온강도와 치밀화가 오히려 감소하였다. 이는 소결 중 내화물 입자와 실리카 바인더와 열팽창계수의 차이에 기인하는 것으로 판단된다. 정밀주조용 지르콘 쉘 주형 제작을 의한 최적의 $R_w$ 값은 0.33인 것으로 나타났다.

• 한국주조공학회지
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• 제20권5호
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• pp.330-335
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• 2000

Functional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported. But a system which can build directly 3D parts of high performance functional material as metal park would get long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we translated the wax patterns to numerous metal tool prototypes by new investment casting process combined conventional investment casting with rapid prototyping & rapid tooling process. With this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P pare to metal part.

• Journal of Microbiology and Biotechnology
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• 제30권6호
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• pp.878-884
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• 2020

Penicillium digitatum and P. italicum are the two important postharvest pathogens in citrus, causing about 90% of the total loss of citrus fruit during storage and transportation. Natural fungicides such as essential oils have been widely used instead of chemical fungicides for preventing and controlling postharvest diseases. In this research, p-anisaldehyde exhibited a strong inhibitory effect on P. digitatum and P. italicum, with the minimum inhibitory concentration and minimum fungicidal concentration values of both being 2.00 μl/ml. Additionally, p-anisaldehyde visibly inhibited both the green mold and blue mold development of citrus fruits inoculated with P. digitatum and P. italicum. The mycelia morphologies of these pathogens were greatly altered, and the membrane permeability and cell wall integrity of mycelia were severely disrupted under p-anisaldehyde treatment. These results suggest that the antifungal activity of p-anisaldehyde against P. digitatum and P. italicum can be attributed to the disruption of the cell wall integrity.

• 한국분말재료학회지
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• 제21권5호
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• pp.366-370
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• 2014

The present study demonstrates the effect of solidification condition on the pore structure in freeze drying process using the slurries of CuO/sublimable vehicles. Camphene and Camphor-45 wt% naphthalene based slurries with 14 vol% CuO powder were frozen into a mold at $-25^{\circ}C$, followed by sublimation at room temperature. The green bodies were hydrogen-reduced and sintered at $500^{\circ}C$ for 1 h. The porous Cu specimen, frozen the CuO/camphene slurry into the heated mold of the upper part, showed large pores with unidirectional pore channels and small pores in their internal wall. Also, it was observed that the size of large pores was decreasing near the bottom part of specimen. The change of pore structure depending on the freezing condition was explained by the nucleation behavior of camphene crystals and rearrangement of solid powders during solidification. In case of porous Cu prepared from CuO/Camphor-naphthalene system, the pore structure exhibited plate shape as a replica of the original structure of crystallized vehicles with hypereutectic composition.

• 한국유기농업학회지
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• 제19권spc호
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• pp.283-286
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• 2011

Powdery mildew and leaf mold were major diseases in organic cultured tomatoes. $NaHCO_3$ and $KH_2PO_4$ were selected as control agents for controlling tomato powdery mildew. Control effect of the selected control agents was increased when they were treated with oil-egg yolk mixtures (OEYO). Also four organic materials used commercially including copper hydroxide and sulfur, showed high control effect more than 90% in green house. Also two organic matters, copper hydroxide and sulfur showed high control effect in farmer's field. When tomatoes were cultivated in plastic house installed with circulation fan, incidence of powdery mildew and leaf mold was reduced by 56% and 60%, respectively.

• 한국식물병리학회지
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• 제1권1호
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• pp.67-71
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• 1985

수원지방의 고추 포장에서 고추 열매에 검은곰팡이병이 심하게 발생하였는데, 이병 열매에서는 모두 Alternaria균이 분리되었다. 분리된 Alternaria균의 분생자경과 분생포자의 형태 및 배양적 특성을 검토한 결과, Alternaria alternate(Fries) Keissler로 동정되었다. 단포자분리하여 배양한 A. alternata의 분생포자현 탁액을 고추 열매에 무상처로 분무접종한 경우, 병반형성이 없거나 미약하게 나타났다. 그러나 사포 혹은 가열한 유리막대로 고추 열매에 상처를 준 다음 분무접종한 결과, 병반이 크게 형성되었으며, 풋고추 보다는 붉은 고추 열매에서 병원력이 더 강하게 나타났다. 파종후 60일된 고추 식물체에 A. alternata의 분생포자현탁액을 분자접종하였으나 잎과 가지에서 병이 발생하지 않았다. 1984년 7월중 수원지방의 고추 포장에서 검은곰팡이병으로 인한 고추 열매의 피해율은 $2.0\~22.5\%$였다.

• 한국정밀공학회지
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• 제16권6호
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• pp.52-57
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• 1999

Funtional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported by song etc. But a system which can build directly 3D parts of high performance functional material as metal part would need long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we tranlsated the wax patterns to numerous metal prototypes by new investment casting process combined conventional investment casting with rapid pototyping & rapid tooling process. with this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P part to metal part.

• 한국식품영양학회지
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• 제33권5호
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• pp.524-531
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• 2020

The purpose of this study was to evaluate the quality properties of Meju prepared by inoculating two strains of Bacillus amyloliquefaciens HJ5-2, and Aspergillus oryzae PS03. The three soybean varieties that include Daewonkong, Daechan, and Saedanbaek were used in this experiment. The fermentation temperature during the Meju aging varied at 20℃, 30℃, and 40℃, respectively. The physicochemical analysis of the soybeans, showed that the cured protein and fat contents were 34.83~43.49% and 12.91~18.90%, respectively. The pH and total acidity were 6.47~6.93 and 0.11~1.22%, respectively. The change in appearance of the Meju was that the yellow-green mold was well formed on seven days at fermentation temperature of 20℃ and 30℃, but at 40℃, there was minimal mold formation and cracking of the surface. The amino nitrogen content was highest on the Daechan Meju at 621.83 mg% for seven days. The amylase increased as the fermentation period increased in all samples, and the protease increased rapidly until the first day of the fermentation, and then gradually increased thereafter. The total number of bacteria increased or decreased as the fermentation proceeded to 6.66~10.07 log CFU/g. The mold counts increased with increasing fermentation period in the range of 6.38~8.79 log CFU/g.

• 식물병연구
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• 제18권4호
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• pp.354-360
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• 2012

총 101종의 식물추출물 가운데 약용식물인 천산용(Dioscorea quinqueloba Thunb.) 추출물이 가장 강한 항균활성을 보유한 것으로 나타나 감귤 녹색곰팡이병(Penicillium digitatum) 방제를 위한 실질적인 농업적 현장적용 가능성을 탐색하였다. 선발된 천산용 추출물은 PDA 배지에 0.5 mg/ml을 처리하였을 때, P. digitatum의 균사생장을 87% 억제하였다. 그리고 추출된 항균활성 물질은 pH, 온도, UV에 영향을 받지 않는 매우 안정한 물질임이 확인되었다. 감귤 저장상태 하에서 녹색곰팡이병 방제를 검정한 결과, 자연적인 병발생을 유도한 후 항균활성 물질을 처리하였을 때 0.3 mg/ml에서 완벽하게 병이 방제되었으며 인위적으로 고농도의 P. digitatum을 접종한 경우에도 0.5 mg/ml 농도에서 100%의 방제효과를 보였다. 이 천연 항균물질을 2 mg/ml 농도로 감귤 과실에 처리하여도 약해가 나타나지 않았으므로, 약해가 없고 방제효과가 우수한 이 식물유래 천연물질은 감귤 저장 중에 발생하는 녹색곰팡이병 방제를 위해 추후 매우 효과적인 농업적 활용이 가능할 것으로 판단된다.

• 한국식품저장유통학회지
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• 제19권6호
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• pp.939-945
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• 2012

상주 지역 곶감의 제조 및 저장 중의 품질열화를 방지하기 위한 기초 연구로서 상주 곶감으로부터 오염균을 분리하여 동정을 실시하였다. 7종의 배지를 사용하여 곶감으로부터 오염균을 분리한 결과 배지 종류별로 오염균수가 $5.18{\times}10^2{\sim}2.31{\times}10^4$ CFU/g으로 나타났다. 곰팡이에 의해 오염된 곶감의 경우 배지 종류에 따라 오염균수가 $1.17{\times}10^6{\sim}1.68{\times}10^7$ CFU/g으로 나타났다. 곶감의 주요 오염균을 조사하기 위해 우점종으로 존재하는 균수를 확인한 결과, 분리된 3종의 곰팡이 중에서 푸른 곰팡이 K2-1이 가장 많은 비율을 차지하여 곶감 오염에 있어 주요 원인균으로 판단하였다. 다음으로 크림색 효모와 연보라색 효모가 많이 상재하고 있는 것으로 나타났다. 분리한 15종의 균주 중 주요 오염 원인균으로 판단되는 푸른 곰팡이 K2-1에 대한 균주 동정을 실시한 결과Penicillium sp.으로 동정되었으며, 곰팡이 K-1과 K-3는 각각 Caldosporium sp.와 Aspergillus sp.으로 동정되었다.