• 한국균학회지
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• 제20권1호
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• pp.58-64
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• 1992

Trichoderma 속의 제균종중에서 10균주를 선별하여 protoplast 형성에 관한 제반조건을 검토하였으며 그 결과는 다음과 같았다. 보편적으로 protoplast 형성에 있어서 삼투안정제의 효과는 ${KCI}>(NH_4)_2{SO_4}>NaCl>mannitol>{MgSO}_4$ 순이었으며, 최적농도는 0.6-0.9M 사이에서 결정되었다. Protoplast형성을 위한 DRISELASE의 최적조건은 pH5.0, 효소농도 2%. 반응시간 4시간, 반응온도 $30^{\circ}C$ 이었다. NOVOZYM 234의 최적조건은 pH 5.5, 효소농도 1%,반응시간 3시간, 반응온도 $30^{\circ}C$ 이었다. Protoplast 생성은 대수증식기 초기와 증기사이의 균사체가 최적이었다. Protoplast 생성에 있어서는 DRISELASE가 효과적이었으나 T. longibruchiatum IAM 13107과 T. viride IAM 5141의 경우에는 NOVOZYM 234가 보다 효과적이었다.

• 한국식품위생안전성학회지
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• 제13권4호
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• pp.332-336
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• 1998

김치숙성중 숙성온도, pH 및 소금농도가 NDMA의 생성량에 미치는 영향과 또한 in vitro에서 온도, pH 및 소금농도가 NDMA의 생성에 미치는 영향을 각각 연구하였다. 배추김치를 저온 냉장온도($4^{\circ}C$)와 실온 ($16{\pm}2^{\circ}C$)에서 6주간 숙성할 때 아질산염과 DMA의 함량변화는 실온에서는 숙성기간에 따라 일정하지 않았으나 저온 냉장 온도에서는 숙성기간 동안 큰 변화 없이 거의 일정하였고,NDMA의 최대 생성량도 $2.69\;\mu\textrm{g}/kg$으로 저온 냉장 때 보다 약 18배 이상 더 많이 생성되었다. 김치 숙성 중 아질산염과 DMA의 함량변화와 NDMA의 생성량과는 관계가 없었으나 pH의 변화는 NDMA 생성량과 같은 관계가 있어 김치 숙성 중 가장 낮은 pH 4.0 부근에서 NDMA의 생성량도 가장 높았다. in vitro 시험에서 NDMA의 생성량은 저온보다는 실온에서 그리고 pH가 낮을수록 더 많이 생성되었고 그 생성량은 온도보다는 pH의 영향이 더 컸다. 보통 소금농도(2.5%)의 김치와 낮은 소금농도(1.5%)의 김치를 각각 숙성할 때 NDMA 의 생성량 변화는 보통 소금농도에서는 숙성기간동안 큰 변화 없이 일정하였고 최대 생성량도 $5.86\;\mu\textrm{g}/kg$으로 낮았으나, 낮은 소금 농도에서는 3주째 최고 $90.0\;\mu\textrm{g}/kg$ 생성되었다. in vitro에서도 소금농도가 높을수록 NDMA의 생성량도 낮았다.

• 한국잠사곤충학회지
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• 제33권2호
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• pp.68-71
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• 1991

뽕나무 고조삽목에 있어서 신광뽕을 삽수로 하고 15일간 온도를 15, 20, 25 및 3$0^{\circ}C$로 달리하여 유합촉진시킨 후 3$0^{\circ}C$ 온실베드에 삽목하였을 경우 온도별 발근생장에 미치는 영향을 검토하였다. 1. 유합촉진온도가 높으면 발아가 촉진되어 25 및 3$0^{\circ}C$의 겨우 각각 삽목 6일과 4일후부터 발아하기 시작하여 15일과 10일 후에 100% 발아하였다. 그러나 15 및 2$0^{\circ}C$에서는 8일후부터 발아하기 시작하여 15일 후에 각각 85%, 92% 발아하였다. 2. 높은 온도에서는 조기에 높은 발근율을 나타내어 삽목 15일 g수에 25-3$0^{\circ}C$에서 97-100%이었고 그 이하의 낮은 온도에서는 93%로서 비교적 낮았으며 35일 후에도 같은 경향이었다. 3. 삽목 15일 후에 뿌리수 및 길이는 온도가 높은 만큼 증대하였으나 35일 후의 뿌리수 및 무게는 2$0^{\circ}C$ 이상에서 차가 없었다.

• 식물병연구
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• 제9권1호
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• pp.47-51
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• 2003

남양주, 양주, 양평에서 파드득나물 균핵병의 발생생태를 조사한 결과, 균핵병은 늦가을부터 초봄까지 주로 동계기간에 발생했으며, 지역별로는 양평에서 발생이 심했다. 포장에서 분리한 파드득나물 균핵병균은 기보고된 Sclerotinia sclerotiorum의 균학적 특성과 일치하였고, 균사생장은 5~3$0^{\circ}C$에서 이루어졌으며, 15~3$0^{\circ}C$에서 활발하게 생장하였다 균핵형성은 20~$25^{\circ}C$에서 많이 형성되었으며, 낮은 온도에서 형성된 균핵의 크기가 큰 경향이었다. 균핵생존율은 균핵크기가 작을수록(~2 mm > 3~4 mm > 5 mm~) 높았으며, 치상온도에서의 정치시간이 길수록 높게 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2989-2994
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• 2007

Gas hydrates are ice-like crystalline compounds that form under low temperature and elevated pressure conditions. Although hydrate formation can pose serious flow-assurance problems in the gas pipelines or facilities, gas hydrates present a novel means for natural gas storage and transportation with potential applications in a wide variety of areas. An important property of hydrates that makes them attractive for use in gas storage and transportation is their very high gas-to-solid ratio. In addition to the high gas content, gas hydrates are remarkably stable. The main barrier to development of gas hydrate technology is the lack of an effective method to mass produce gas hydrate in solid form. The first objective of this study is investigating the characteristics of gas hydrate formation related to several factors such as pressure, temperature, water-to-storage volume ratio, concentration of SDS, heat transfer and whether stirred or not respectively. And the second objective is clarifying the relation between the formation efficiency and each factor in order to find the proper way or direction to improve the formation performance.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.186-187
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• 2008

Electrical resistivity in hydrate-bearing sediments is sensitive to porosity, gas hydrate saturation, gas content, pore fluid composition, and temperature, so electrical measurements such as well logs and electromagnetic surveys have been used to explore gas hydrate-bearing formation. The high pressure tomography cell is designed considering the effect of electrode configuration and electrical shielding on tomography measurements and the safety. The evolution of electrical conductivity during $CO_2$ hydrate formation and dissociation reflects the combined effects of concurrent changes that include ionization of dissolved $CO_2$, temperature-dependent ionic mobility, changes in the degree of saturation, ion exclusion, surface conduction, and porosity changes. Measurements during hydrate formation and dissociation require careful analysis to properly interpret signatures, in particular when out-of plane conductivity anomalies prevail.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1276-1280
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• 2003

Thermal behavior of bromphenols was investigated by direct pyrolysis at high temperature. The thermal degradation products formed by the pyrolysis of mono-bromophenols (o-, m-, and p-) were identified by gas chromatography-mass spectrometry. During the pyrolysis reactions, several kinds of dioxins and furans were produced, and the relative ratio of pyro-products was dependent on the substituted position of bromine in phenolic structure due to the effect of symmetry and steric hindrance. The formation of dioxins can be explained by the phenoxy radical addition and Br atom elimination at an ortho-carbon site on phenolic structure. On the other hand, the formation of furans can be explained by the ortho-ortho carbon coupling of phenoxy radicals at unsubstituted sites to form o, o'-dihydroxydiphenyl intermediate via its keto-tautomer, followed by $H_2O$ elimination. The pyrolysis temperature has also a substantial effect on the dimerized products quantities but little effect on the type of pyro-products. Moreover, the formation mechanism of pyro-products was suggested on the basis of products identified.

• 설비공학논문집
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• 제23권12호
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• pp.769-775
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• 2011

Methane hydrate is formed by physical binding between water molecules and methane gas, which is captured in the cavities of water molecules under the specific temperature and pressure. $1m^3$ hydrate of pure methane can be decomposed to the methane gas of $172m^3$ and water of $0.8m^3$ at standard condition. Therefore, there are a lot of practical applications such as separation processes, natural gas storage transportation and carbon dioxide sequestration. For the industrial utilization of hydrate, it is very important to rapidly manufacture hydrate. So in this study, hydrate formation was experimented by adding THF and oxidized carbon nanotubes in distilled water, respectively. The results show that when the oxidized carbon nanofluids of 0.03 wt% was, the amount of gas consumed during the formation of methane hydrate was higher than that in the THF aqueous solution. Also, the oxidized carbon nanofluids decreased the hydrate formation time to a greater extent than the THF aqueous solution at the same subcooling temperature.

• 한국세라믹학회지
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• 제52권5호
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• pp.331-337
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• 2015

$LaBO_3$ (B = Cr, Mn, Fe, Co, and Ni) perovskites, the most common perovskite-type mixed ionic-electronic conductors (MIECs), are promising candidates for intermediate-temperature solid oxide fuel cell (IT-SOFC) cathodes. The catalytic activity on MIEC-based cathodes is closely related to the bulk ionic conductivity. Doping B-site cations with other metals may be one way to enhance the ionic conductivity, which would also be sensitively influenced by the chemical composition of the dopants. Here, using density functional theory (DFT) calculations, we quantitatively assess the activation energies of bulk oxide ion diffusion in $LaBO_3$ perovskites with a wide range of combinations of B-site cations by calculating the oxygen vacancy formation and migration energies. Our results show that bulk oxide ion diffusion dominantly depends on oxygen vacancy formation energy rather than on the migration energy. As a result, we suggest that the late transition metal-based perovskites have relatively low oxygen vacancy formation energies, and thereby exhibit low activation energy barriers. Our results will provide useful insight into the design of new cathode materials with better performance.

• 설비공학논문집
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• 제11권5호
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• pp.588-597
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• 1999

Sokkuram grotto, a UNESCO cultural heritage in Kyongju Korea, was originally covered with crushed rocks over its dome with ventilating holes. The grotto was perfectly preserved for more than 12 centuries until the upper structure was replaced with a concrete dome in the early 20th century to protect from total collapse. Since then, heavy dew formed on the granite surface to seriously damage the sculptures until it was further remodeled with air-conditioning facilities in the 60s. It is considered that the original upper porous structure had a dehumidifying capability. This research is made to unveil the dehumidifying mechanism of the rock layer during the rainy season in that area. A rock layer and a concrete layer are tested in a temperature/humidity-controlled room. No dew formation is observed for the two specimen for continued sunny days or continued rainy days. However, heavy dew formed on the concrete surface for a sunny day after long rainy days. It is thought that the sun evaporates water on the ground and dew is formed at the surface as the highly humid air touches the yet cold concrete. On the contrary, no dew formation is observed for the rock layer at any time. Even in the above worst situation, air flows downward through the cool rock layer and moisture is removed before reaching inside. Temperature measurement, flow visualization, observation of dew formation and measurement of air velocity are made to verify the mechanisms.