• The Korean Journal of Mycology
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• v.20 no.1
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• pp.58-64
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• 1992

This research was focused on investigation of the general condition for protoplast formation of Trichoderma speues. for protoplast formation, the mycelia cultured in YM medium were collected from each growth phase and were treated with the Iytic enzymes. This procedure was carried out by all strains. The most optimal conditions of NOVOZYM 234 and DRISELASE were determined by T. saturnisporum IAM 12535 and T. longibruchiatum IBM 13107, respectively. The effect of osmotic stabilizers appeared ${KCI}>(NH_4)_2{SO_4}>NaCl>mannitol>{MgSO}_4$ and the optimal concentration of each osmotic stabilizer wns determined by 0.6-0.9 M. The optimal condition of DRISELASE for protoplast formation ; optimal pH 5.0, optimal concentration, 2%, optimal reaction time, 4 hours, and optimal temperature, $30^{\circ}C$. The optimal condition of NOVOZYM 234 for protoplast formation ; optimal pH 5.5, optimal concentration 1%, optimal reaction time 3 hours, and optimal temperature $30^{\circ}C$. The optimal culture period of mycelia for protoplast formation was between the initial and the middle exponential phase. Generally, DUSELASE was more effective than NOVOZYM 234 on protoplast formation except for T. longibruchiatum IAM 13107 and T. viride IAM 5141.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.332-336
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• 1998

The effect of ripening temperature, pH and salinity on the formation of Nnitrosamine (NA) during Kimchi fermentation and in vitro was studied, respectively. During Kimchi fermentation for six weeks at cold storage temperature ($4^{\circ}C$) and room temperature ($16{\pm}2^{\circ}C$), the contents of nitrite and dimethylamine (DMA) showed variation at room temperature but no variation at cold storage temperature. The maximum generation of nitrosodimethylamine (NDMA) resulted low content ($2.69\;\mu\textrm{g}/kg$) at cold storage temperature but started to increase after one week fermentation and reached to the 18-fold higher generation ($49.6\;\mu\textrm{g}/kg$) at room temperature. During Kimchi fermentation, no correlation was observed between the variation of nitrite and DMA content and the generation of NDMA. However, pH showed effective relation to NDMA generation such as the highest NDMA generation was obtained at lowest pH 4. During in vitro test, higher temperature and lower pH resulted more NDMA generation and generation amount was affected more by pH. Also, the salinity of Kimchi provided inhibitory effects on the formation of NDMA. NDMA was produced $5.86\;\mu\textrm{g}/kg$ at normal salinity (2.5%) but $90.9\;\mu\textrm{g}/kg$ at lower salinity (15%) after three week. The higher salinity showed lower formation of NDMA in vitro test, too.

• Journal of Sericultural and Entomological Science
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• v.33 no.2
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• pp.68-71
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• 1991

Mulberry cuttings from shoots of Shinkwangppong(Morus bombycis koidz.) had been callused in vermiculite separately at 15, 20, 25 and 30$^{\circ}C$ for 15 days before transplanting them in greenhouse to make clear the effect of temperature on root formation and growth is as follow. The buds of cuttings started sprouting in 4 and 6 days of callusing at 30 and 25$^{\circ}C$, respectively, reaching 100% budding in 10 and 15 days of callusing. Budding was delayed, however, at low temperature, showing 86% and 92% at 15 and 20$^{\circ}C$, respectively, in 15 days. Rooting from the cuttings was also accelerated at high temperature, showing 97-100% rooting at 25$^{\circ}C$ and 30$^{\circ}C$, in 15 days of callusing but no more than 93% at low temperature even in 35 days. Although high temperature increased root number and length after 15 days in callusing, no differences showed in the number and the weight at more than 20$^{\circ}C$ in 35 days of cuttings.

• Research in Plant Disease
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• v.9 no.1
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• pp.47-51
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• 2003

Sclerotinia rot of C. japonica caused by Sclerotinia sclerotiorum was observed throught the growing season in the vinylhouse at the Namyangiu, Yangju and Yangpyung areas. The disease was commonly occurred at late autumn after transplanting and continuously increased until spring in next year, The disease was especially severe at the Yangpyung area among three areas. Three isolates of S. sclerotiorum obtained from C. japonica in different geographic areas were evaluated for ability of sclerotia formation and viability under different temperature. Temperature for mycelial growth ranged from 5 to 3$0^{\circ}C$, with optimum temperature at 15~3$0^{\circ}C$. Sclerotia were fewer formed at low temperature, but their size was larger than that at high temperature. Small size of sclerotia was more viable than those of large size at high temperature. Based on the differences in viability of sclerotia, the relative ranks of sclerotia were in order ~2 mm > 3~4 mm > 5 mm~.

• Proceedings of the KSME Conference
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• 2007.05b
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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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• 2008.10a
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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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• v.24 no.9
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.12
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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.

• Journal of the Korean Ceramic Society
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• v.52 no.5
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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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.