• Bulletin of the Korean Chemical Society
• /
• v.18 no.5
• /
• pp.534-540
• /
• 1997

4H,6H-Furo[3,4-c]isoxazoles (Ⅰ-Ⅳ), potential fungicides, have been designed and synthesized via intramolecular [2+3] cycloaddition of nitroalkyne 3 as a key step. The broad spectrum of fungicidal activities of furoisoxazoles (Ⅰ-Ⅳ) were observed on plant pathogens at 250 ppm. Furoisoxazoles Ⅱ, Ⅲ with chlorophenyl at 6-position and methyl or alkylated oxime group at 3-position gave effective control of plant diseases. The furoisoxazole Ⅳ with a chlorophenyl group at 4-position also resulted in high fungicidal activities.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.11
• /
• pp.837-842
• /
• 2010

This paper describes the crystallinity, growth rate, and surface morphology of single crystalline 3C-SiC (cubic silicon carbide) thin films grown with several carbonization conditions such as temperature, $C_3H_8$ flow rate, time. In case of carbonization, an increase in the carbonization temperature caused a increase in the size and numbers of unsealed void (big black spot) which decrease the crystallinity. In addition, optimal $C_3H_8$ flow rate made carbonization layer form well and prevented the formation of voids. Also, after a period of time, the growth of carbonization layer did not increase no more. The single crystalline 3C-SiC thin films on optimal carbonized Si substrate showed an improvement on the crystallinity, the growth rate, the roughness, and the carrier concentration.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.4
• /
• pp.556-562
• /
• 1997

Depletion of nitrite by lactic acid bacteria isolated from Kimchi and the effects of pH and temperature on depletion of nitrite in Lactobacillus MRS broth were investigated. Depletion of nitrite by Lactobacillus plantarum and Lactobacillus sake was low in initial stage of growth but increased during growth at 15 and 2$0^{\circ}C$. L. plantarum and L. sake depleted than 90 and 75% of nitrite(250$\mu\textrm{g}$/$m\ell$) in 1 day of growth at 25 and 3$0^{\circ}C$, respectively, but depleted almost all of nitrite in 2 days. While the effect of Leuconostoc mesenteroides (150$\mu\textrm{g}$/$m\ell$) was lower compared to Lactobacillus(250$\mu\textrm{g}$/$m\ell$). In addition, even high concentrations(600 and 900 $\mu\textrm{g}$/$m\ell$) of nitrite was depleted at 2 days of growth by L. plantarum. pH of growing broth decreased as the increase of growth time and temperature, and depletion of nitrite in- creased as the decrease of pH of growing culture. However, pH of broth related with the decrease of depletion of nitrite at 25 and 3$0^{\circ}C$, but not at 15 and 2$0^{\circ}C$. Therefore, depletion of nitrite was greatly affected by growth temperature rather than by pH.

• Korean Journal of Materials Research
• /
• v.24 no.1
• /
• pp.53-59
• /
• 2014

The corrosion resistance of submerged entry nozzle (SEN) materials were investigated for high-class steel manufacturing. Composite samples were fabricated by mixing $ZrO_2$, $Al_2O_3$, MgO, mullite, spinel, and carbon. The raw materials were mixed with attrition milling, compacted in a uniaxial pressure of 200MPa and calcined at $1000^{\circ}C$ for 3 h in $N_2$ atmosphere. The bulk density and apparent porosity of the calcined samples were measured by the liquid displacement method in water using Archimedes's principle. The corrosion resistance of the samples were measured by cup test with mold powder at $1550^{\circ}C$ for 2 h. The microstructure and elemental analysis of samples were observed by scanning electron microscopy (SEM), energy dispersive spectrum (EDS), and X-ray diffraction pattern (XRD). The XRD result shows that the starting raw materials were crystalline phase. The microstructure of fabricated specimen was investigated before and after corrosion tests at $1000^{\circ}C$ and $1550^{\circ}C$ for 2h. $ZrO_2$-C composite showed good resistance in the slag corrosion test. Among the composite oxide materials, $ZrO_2-Al_2O_3$-C and $ZrO_2$-MgO-C showed better resistance than $ZrO_2$-C in the slag corrosion test. The diameter variation index of $ZrO_2$-C refractory was 16.1 at $1000^{\circ}C$ for 2 h. The diameter variation index of the $ZrO_2-Al_2O_3$-C refractory was larger than that of the $ZrO_2$-C refractory at $1550^{\circ}C$ for 2 h.

• Microbiology and Biotechnology Letters
• /
• v.32 no.4
• /
• pp.317-321
• /
• 2004

We selected a solvent for producing antioxidants from sporophyll of Undaria pinnatOptimum extraction condition for antioxidant ability(Y) of sporophyll of U. pinnatifida was investigated using response surface methodology(RSM). A compound central design was used with variables ($X_1$)temperature($^{\circ}C$) (3.4; 20; 60; 100; 116.6); ($X_2$) pH(1.8; 3; 6; 9; 10.2) and ($X_3$) treatment time(min) (1.7; 10; 30; 50; 58.3). Antioxidant activities were increased with decreasing pH and increasing temperature. The optimal extraction conditions for antioxidant ability(Y) of sporophyll of U. pinnatifida were found to be temperature $51.55^{\circ}C$, pH 4.2 and treatment time 28.2 min. Among the variables tested, pH showed greater significant facin extraction of antioxidants from sporophyll of U. pinnatifida.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.3
• /
• pp.305-310
• /
• 1997

The synthesis and characterization of the platinum heterocyclic carboxaldehyde thiosemicarbazone complexes [NC5H4CRNNC(S)NHR'PtCl] (R=H, R'=CH3(1); R=CH3, R'=CH3(2); R=CH3, R=H(3)) and diphenylphosphinophenyl carboxaldehyde thiosemicarbazone complexes [Ph2PC6H4CHNNC(S)NHRPtCl] (R=CH3(5); R=iC3H7(6); R=Ph(7)) are described. Compounds 1-3 were prepared by reaction of Pt(SEt2)2Cl2 with 2-acetylpyridine-4-alkylthiosemicarbazone in the presence of NEt3. Compounds 5-7 were prepared using Pt(SEt2)2Cl2 in toluene with diphenylphosphinophenyl carboxaldehyde alkylthiosemicarbazone. The compounds have been characterized by microanalysis, NMR (1H, 13C, 31P) spectroscopy, and single-crystal X-ray diffraction. X-ray single crystal diffraction analysis reveals that compound 5 is a mononuclear platinum compound with P,N,S-coordination mode.

• Journal of the Korean Ceramic Society
• /
• v.53 no.6
• /
• pp.597-603
• /
• 2016

Tantalum carbide, which is one of the ultra-high temperature ceramics, was deposited on graphite by low pressure chemical vapor deposition from a $TaCl_5-C_3H_6-Ar-H_2$ mixture. To maintain a constant $TaCl_5/C_3H_6$ ratio during the deposition process, $TaCl_5$ powders were continuously fed into the sublimation chamber using a screw-driven feeder. Sublimation behavior of $TaCl_5$ powder was measured by thermogravimetric analysis. TaC coatings have various phases such as $Ta+{\alpha}-Ta_2C$, ${\alpha}-Ta_2C+TaC_{1-x}$, and $TaC_{1-x}$ depending on the powder feeding methods, the $C_3H_6/TaCl_5$ ratio, and the deposition temperatures. Near-stoichiometric TaC was obtained by optimizing the deposition parameters. Phase compositions were analyzed by XRD, XPS, and Raman analysis.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2004.11a
• /
• pp.35-36
• /
• 2004

A total of 1.200 eggs obtained from 312-day-old Hy-line Brown layer breeder hens and 319-day-old Hy-line Brown commercial layer hens (600 eggs obtained from each ones) were used to investigate the effects of storage period, storage temperature, and insemination of hens on the change of albumen height, Haugh unit (HU), albumen pH, shell strength, and yolk color. Eggs were stored up to 14 days after lay at $3\;^{\circ}C\;or\;10\;^{\circ}C$ and sampled one day after stored and then 24 hours interval. Longer periods of storage resulted in lower albumen height and HU at both storage temperatures, but in higher albumen pH. The eggs stored at $3\;^{\circ}C$ were generally higher in HU and lower in albumen pH than the ones stored at $10\;^{\circ}C$. There was no statistically difference although the eggs obtained from the non-inseminated-hens were slightly higher in albumen height and HU than the eggs obtained from the inseminated-hens. Whereas, the eggs obtained from the non-inseminated-hens in the albumen pH of eggs stored at $3\;^{\circ}C$ was significantly (P<0.05) higher than the ones obtained from the inseminated-hens, but the albumen pH of eggs stored at $10\;^{\circ}C$ did not differ each other. The mean shell strength of the eggs obtained from the inseminated-hens was significantly (P<0.05) stronger than that of the eggs obtained from the non-inseminated-hens at both storage temperatures. Albumen height and albumen pH were negatively correlated(P<0.01~0.001) in both inseminated and non-inseminated-hen's egg groups. The degree of yolk colors were not significantly changed overall of the experimental periods in both storage temperatures. The study suggests that the change of egg freshness such as albumen height and HU are relatively more associated with storage period and storage temperature than insemination or non-insemination of hens.

• BMB Reports
• /
• v.42 no.4
• /
• pp.223-226
• /
• 2009

We measured the pH-induced spectral changes of yeast iso-1-cytochrome c on silver nanoparticle surfaces using surface-enhanced resonance Raman scattering (SERRS) at 457.9 nm. At a pH of ~3, the Met80 ligand in yeast iso-1-cytochrome c is assumed to dissociate, leading to a marked conformational change as evidenced by the vibrational spectral shifts. The Soret band at ~410 nm in the UV-Vis spectrum shifted to ~396 nm at pH~3, indicating a transition from a low spin state to a high spin state from a weak interaction with a water molecule. Thus, SERRS spectroscopy can measure the pH-induced denaturalization of cyt c adsorbed on metal nanoparticle surfaces at a lower concentration with a better sensitivity than ordinary resonance Raman spectroscopy.

• Korean journal of food and cookery science
• /
• v.13 no.5
• /
• pp.578-584
• /
• 1997

Fermentation temperature and salt concentration of Dongchimi were studied for the development of low salt Dongchimi juice. The juice was prepared by soaking the radish in brine solution of 0.3∼3.0% and fermented at the temperature range of 10∼30$^{\circ}C$. The fermentation proceeded faster at higher temperature. However, the salt concentration effect was dependent on the temperature. Fermentation in 3.0% NaCl solution resulted the fastest reach to pH 3.8 followed by 0.5% NaCl at 10 and 20$^{\circ}C$, while higher NaCl concentration caused a decrease in the fermentation rate at 30$^{\circ}C$. Comparison of flavor of the juice of pH 3.9 showed that fresh sourness was high in the juice prepared at 20$^{\circ}C$ and in 0.5% NaCl. The preference test also showed the juice of pH 3.8∼4.0 fermented in 0.5% NaCl at 20$^{\circ}C$ to be the most preferable one. The salt concentration lower than 0.5% at 20$^{\circ}C$ resulted in faster fermentation and high values in turbidity. However 0.5% NaCl was scored high in flavor acceptability.