• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.534-538
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• 1990

Chromium(Ⅵ) compound, [$C_9H_7$NH]$_2Cr_2O_7$ has been prepared by the reaction of isoquinoline with chromium trioxide under the presence of water. [$C_9H_7$NH]$_2Cr_2O_7$ is nonhydroscopic and dissolved in water very well. Structure of [$C_9H_7$NH]$_2Cr_2O_7$ is identified by FTIR spectra and elemental analysis data. The ability of [$C_9H_7$NH]$_2Cr_2O_7$ for the oxidation of alcohols were examined in methylene chloride. [$C_9H_7$NH]$_2Cr_2O_7$ was found as efficient oxidizing agent for the conversion of allyl, primary and secondary alcohols to the corresponding aldehydes or ketones.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.4
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• pp.178-184
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• 2010

The $12CaO{\cdot}7Al_2O_3$(C12A7) powders were successfully synthesized using combustion method with microwave-assistant and C12A7:H were fabricated by post-annealed process in Ar/H atmosphere. X-ray diffraction patterns and TGDSC were used for investigating to the precursors of crystalline and reaction depending on temperature. C12A7:H that was treated post-annealed process were investigated TG-MS and Hall-measurement for confirming H ions doping and checking electrical resistivity of C12A7:H. H ion substituted to $O^{2-}$ ions in the C12A7 cages were confirmed at $289.5^{\circ}C$ by TG-MS and C12A7:H calcined at $1000^{\circ}C$ in Ar/H=8:2 atmosphere for 8~10 h has low electrical resistivity about $10^2{\Omega}{\cdot}cm$ at room temperature.

• Journal of Food Hygiene and Safety
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• v.12 no.3
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• pp.200-204
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• 1997

Effects of benzoate (0~0.6 g/$\ell$ ) and sorbate (0~2.0 g/$\ell$) on the growth of Escherichia coli O157:H7 in tryptic soy broth at various pH levels (4~8) and temperatures (4$^{\circ}C$, 37$^{\circ}C$) were investigated. Benzoate and sorbate were inhibited the growth of E. coli O157:H7 up to 12 hours cultivation at 4$^{\circ}C$, and 2.0 g/$\ell$ sorbate was only inhibited during 48 hours cultivation at 37$^{\circ}C$. Among the pH levels tested, pH 4 showed significant inhibitory effect against the E. coli O157:H7 on 4$^{\circ}C$ and at 37$^{\circ}C$, respectively. When used in combination 0.2 g/$\ell$ benzoate and sorbate were completely inhibited the growth of E. coli O157:H7 on pH 4 and at 37$^{\circ}C$. While on pH 5 at 4$^{\circ}C$, all of the concentration tested did not exert any inhibitory effect. The combined effects were retarded more than single treatment of E. coli O157:H7.

• Membrane Journal
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• v.24 no.4
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• pp.259-267
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• 2014

PEBAX[poly(ether-block-amide)-ZIF-8(zeolitic imidazolate framework) composite membranes were prepared with different amounts of ZIF-8; 0, 1, 3, 7, 10, and 20 wt%. Gas permeation experiment were performed by varying the temperature of 25, 35, $40^{\circ}C$ under condition $6kgf/cm^2$. Gas permeability of $C_3H_6$, $C_3H_8$ and selectivity ($C_3H_6/C_3H_8$) were investigated by increasing the amount of ZIF-8 in the PEBAX. The gas permeability of $C_3H_6$ and $C_3H_8$ increased as ZIF-8 content increased among 0 to 7 wt% range and decreased among 7 to 20 wt% range. When the ZIF contents of PEBAX-ZIF composite membrane were 7 wt%, the selectivity ($C_3H_6/C_3H_8$) was taken between 3.6 and 3.8 value and also had the lowest activation energy.

• Journal of Food Hygiene and Safety
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• v.12 no.4
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• pp.304-309
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• 1997

A study was undertaken to determine the thermal inactivation of Escherichia coli O157:H7 as influenced by the effects of temperature, time, suspension medium and ascorbate. Tryptic soy broth was more heat resistant than pfosphate buffer (pH 7.1), with D values of 1.52~1.68 min at 6$0^{\circ}C$ and 1.51~1.63 min at 7$0^{\circ}C$ compared with 1.52~1.65 min at 6$0^{\circ}C$ and 1.26~1.61 min at 7$0^{\circ}C$ for phosphate buffer as suspension medium. E. coli O157:H7 was completely inhibited within 30 min when small inoculum (106 CFU/$m\ell$) was heated at 7$0^{\circ}C$. When E. coli O157:H7 was preheated at 48$^{\circ}C$ for 60 min in phosphate buffer before heating, D values were 1.28~1.60 min at 6$0^{\circ}C$, and 1.13~1.56 min at 7$0^{\circ}C$, showing that preheating increases the heat resistance of the strain. Phosphate buffer containing ascorbate (0.001 M) was enhanced the thermal inactivation of the strain when inoculated as large inoculum (109 CFU/$m\ell$), while ascorbic acid was no effect at low cell concentrations (109 CFU/$m\ell$).

• Journal of the Korean Chemical Society
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• v.17 no.3
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• pp.145-153
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• 1973

The temperature effects on the equilibria between polymolybdatd anions in 1M sodium perchlorate solution has been investigated in the temperature range of 20~50$^{\circ}$C. The polymolybdate anions formed are heptamolybdate ($Mo_7O_{24}^{6-}$) ions and the protonized forms of heptamolybdate ions ($H_LMo_7O_{24}^{(6-L)-}$). The equilibrium constants for the formation of heptamolybdate ions calculated by Sillen's method are as follow;$8H^{+}+7MoO_4^{2-}=Mo_7O_{24}^{6-}+4H_2O$, $k_{7.8}=2.77{\times}10^{53}:20^{\circ}C= 9.29{\times}10^{51}:40^{\circ}C$,$k_{7.8}= 4.22{\times}10^{52}:30^{\circ}C = 9.29{\times}10^{51}:50^{\circ}C$ The enthalpy change for calculated for the above reaction is 31.51 kcal/mole. A method of calculation of the equilibrium constants for the formation of protonized heptamolybdate ions from heptamolybdate ions and hydrogen ions has been derived. The equilibrium constants calculated for the formation of protonized heptamolybdate ions are as follow; $ LH^++ Mo_7O_{24}^{-6} = H_LMo_7O_{24}^{(6-L)-} : L = 1\;or\;2$, $k_1 = 2.31{\times}10^4=2.53{\times}10^4=2.76{\times}10^4= 3.10{\times}10^4$, $k_2 = 6.19{\times}10^7\;20^{\circ}C = 7.80{\times}10^7\;30^{\circ}C = 1.22{\times}10^8\;40^{\circ}C = 2.03{\times}10^8\;50^{\circ}C$The enthalpy change for the following step reactions are as follow;$H^{+}+Mo_7O_{24}^{6-}= HMo_7O_{24}^{5-}\;{\Delta}H^{\circ}=1.90 kcal/mole$, $2H^{+}+Mo_7O_{24}^{6-}=H_2Mo_7O_{24}^{4-}\;{\Delta}H^{\circ}=7.50kcal/mole$

• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.495-499
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• 2018

The reduction effect of UV-C irradiation and mild heat treatment was examined against Escherichia coli O157:H7 and Salmonella Typhimurium on black pepper powder. E. coli O157:H7 (ATCC 35150) and S. Typhimurium (ATCC 19585) were inoculated onto black pepper powder at approximately $10^7$ and $10^6CFU/g$, respectively. E. coli O157:H7 and S. Typhimurium were treated with UV-C and mild heat at $60^{\circ}C$. A UV-C intensity ($2.32W/cm^2$ ) was used for 10 min to 70 min at $60^{\circ}C$. After UV-C and heat treatment at $60^{\circ}C$, microbial analysis and color change of black pepper powder was conducted. E. coli O157:H7 and S. Typhimurium were reduced by a level of 1.89 and 2.24 log CFU/g, respectively, when treated with UV-C alone for 70 min. And E. coli O157:H7 and S. Typhimurium were reduced by 2.22 and 5.10 log CFU/g, respectively, when treated with mild heat treatment at $60^{\circ}C$ alone for 70 min. But when combined with UV-C and mild heat, it showed higher levels of reduction by 2.46 and 5.70 log CFU/g. S. Typhimurium was more easily reduced than E. coli O157:H7. Color values were not significantly (p > 0.05) different in all treated samples. Therefore, these results suggest that the combined treatment with UV-C and mild heat was effective to inactivate the food pathogens in black pepper powder and can be used as a food industrial microbial intervention method.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.549-554
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• 1993

The CO substitution reactions in the complex, $Cp^*(C_5H_7)$CrCO with $PR_3(PR_3=PMePh_2,\;P(OCH_3)_3,\;PMe_2Ph)$ were investigated spectrophotometrically at various temperatures. For the reaction rates, it was suggested that the CO substitution reaction took place by first-order (dissociative) pathway. Activation parameters in decaline are ${\Delta}H^{\neq}= 21.99{\pm}2.4$ kcal/mol, ${\Delta}S^{\neq}= 8.9{\pm}7.1$ cal/mol·k. Unusually low value of ${\Delta}S^{\neq}$, suggested an ${\eta}^5-S{\to}\;{\eta}^5$-U conversion of the pentadienyl ligand. At various temperature, the rates of reaction for the Cp(pdl)CrCO complexes increase in the order $Cp^*(C_5H_7)$-CrCO < Cp$(C_5H_7)$CrCO < Cp(2,4-$C_5H_{11}$)CrCO, which can be attributed to the usual steric acceration or electronic influence for the ligand substitution of metal complexes. This suggestion was confirmed by the extended-Huckel molecular orbital (EHMO) calculations, which revealed that the energy of $[Cp^*(U-C_5H_7)Cr]^{\neq}$ transition state is about 4.93 kcal/mol lower than that of [Cp(S-$C_5H_7)Cr]^{\neq}$ transition state, and the arrangement of the overlap populations between Cr and the carbon of CO is $Cp^*(C_5H_7)$CrCO > Cp($C_5H_7$)CrCO > Cp(2,4-$C_7H_{11}$)CrCO.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.7
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• pp.511-515
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• 2011

The aim of this study was to investigate the efficiency of temperature, light intensity and pH on the growth rate of Chlorella vulgaris (C. vulgaris). The size of C. vulgaris (FC-16) was $3-8{\mu}m$, having round in shape. The cells of C. vulgaris (FC-16) was cultured in the Jaworski's Medium with deionized water. To evaluate the efficiency of temperature, light intensity and pH on the growth rate of C. vulgaris, six different fractions of temperature ($10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$), various light intensities ($100-800{\mu}Em^{-2}s^{-1}$) and seven different fractions of pH (3, 4, 5, 6, 7, 7.5, 9) were prepared. The growth rate of C. vulgaris cultivation was approximately 5.2 to 5.5 times faster, the concentration of Chlorophyll a was also 5 to 5.5 times higher, and cell volume per unit area was 14% higher at $25^{\circ}C$ to $30^{\circ}C$ than those at $10^{\circ}C$. Therefore, the optimal temperature for cultivation of C. vulgaris was estimated $25^{\circ}C$ to $30^{\circ}C$. The growth rate of C. vulgaris increased slowly up to 5 days, exploded after 5 days until 15 days, and then stoped after that. The optimum cultivation period of C. vulgaris was estimated as 15 days. The optimum pH for the growth rate of C. vulgaris was determined pH 7 to 7.5.

• Journal of the Korean Ceramic Society
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• v.44 no.1 s.296
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• pp.37-42
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• 2007

The preparation of $TiC_{0.7}N_{0.3}$ powder by SHS in the system of $Ti-TiH_2-C$ ($N_2$ atmosphere) was investigated in this study. In the preparation of $TiC_{0.7}N_{0.3}$ powder, the effect of gas pressure, compositions such as Ti, $TiH_2$, C, and additive in mixture on the reactivity were investigated. At 50 atm of the initial inert gas pressure in reactor, the optimum composition for the preparation of pure $TiC_{0.7}N_{0.3}$ was $0.75Ti+0.25TiH_2+0.7C+0.5NaCl$. The $TiC_{0.7}N_{0.3}$ powder synthesized in this condition was a single phase with irregular shape.