• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.73.1-73
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• 2002

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.582-588
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• 1997

Synthetic reaction of TAME, ETBE, and MTBE compounds used largely for gasoline octane number enhancer to prevent air pollution was investigated using heteropolyacid catalyst in a fixed bed flow reactor. In the synthetic reaction of TAME, ETBE and MTBE, after hetero atom being replaced with poly atom, the activity of the catalyst, $H_4SiW_{12}O_{40}$ with coordinated bond with W and an hetero atom of Si was the highest among the catalysts tested. Also the activity depended upon the metals replaced which are related to the catalyst acidity. $FeHPW_{12}O_{40}$ and $K_3PM_{o12}O_{40}$ catalysts showed high activity in TAME synthesis, while they were not effective in ETBE and MTBE synthesis. In this study catalysts showing high activity were selected and mixed with equal weight combination of $H_4SiW_{12}O_{40}$ and $Sr_2SiW_{12}O_{40}$ ;$H_4SiW_{12}O_{40}$ and $NaH_2PW_{12}O_{40}$ ; $Fe_{1.5}PW_{12}O_{40}$ and $Mg_2SiW_{12}O_{40}$ ; $Mg_2SiW_{12}O_{40}$ and $Ba_2SiW_{12}O_{40}$. The mixed heteropolyacid catalysts showed higher TBA conversion rate and better selectivity of ETBE and MTBE than the single catalysts.

• KSBB Journal
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• v.19 no.1
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• pp.50-56
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• 2004

The aim of this work was to investigate the purification and characterization dixoygenases isolated from Delftia sp. JK-2, which could utilize aniline, benzoate, and p-hydroxybenoate as sole carbon and energy source. Catechol 1,2-dioxygenase (C1, 2O), catechol 2,3-dioxygenase(C2, 3O), and protocatechuate 4,5-dioxygenase(4,5-PCD) were isolated by benzoate, aniline, and p-hydroxybenzoate. In initial experiments, several characteristics of C1 ,2O, C2, 3O, and 4,5-PCD separated with ammonium sulfate precipitation, DEAE-sepharose, and Q-sepharose were investigated. Specific activity of C1 ,2O, C2, 3O, and 4,5-PCD were approximately 3.3 unit/mg, 4.7 unit/mg, and 2.0 unit/mg. C1 ,2O and C2, 3O demonstrated their enzyme activities to other substrates, catechol and 4-methylcatechol. 4,5-PCD showed the specific activity to the only substrate, protocatechuate, but the substrates(e.g., catechol, 3-methylcatechol, 4-methylcatechol, 4-chlorocatechol, 4-nitrocatechol) did not show any specific activities in this work. The optimum temperature of C1, 2O, C2, 3O, and 4,5-PCD were 30$^{\circ}C$, and the optimal pHs were approximately 8, 8, and 7, respectively. Ag$\^$+/, Hg$\^$+/, Cu$\^$2+/ showed inhibitory effect on the activity of C1, 2O and C2, 3O, but Ag$\^$+/, Hg$\^$+/, Cu$\^$2+/, Fe$\^$3+/ showed inhibitory effect on the activity of 4,5-PCD. Molecular weight of the C1, 2O, C2, 3O, and 4,5-PCD were determined to approximately 60 kDa,35 kDa, and 62 kDa by SDS-PAGE.

• Korean journal of applied entomology
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• v.35 no.4
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• pp.297-301
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• 1996

This test has been carried out to evaluate the effect of temperature on the growth of the insecticide susceptible strain, URY-O nomal genotype and insecticide resistant strain, O-RT abnormal genotype, and ABURABI nomal genotype. The nymphal periods were not significantly different between URY-O and O-RY strains at $25^{\circ}C$. At $30^{\circ}C$, susceptible strain URY-O could give birth to offsprings almost nomally, while resistant strain O-RY could not produce any offspring for 20 days which results in nymphal death. The numbers of offsprings of strain URY-O and strain ABURABI were not different between $25^{\circ}C\;and\;28^{\circ}C$, but strain O-RY, when it was reared at $28^{\circ}C$, could produce offsprings only 10% of those at $25^{\circ}C$. Body weight of strain URY-O and strain ABURABI were 0.22mg/female and 0.27mg/female, respectively at $28^{\circ}C$, however that of O-RY was only 0.16mg/female, showing considerable difference between normal and abnormal genotype. Substrain O-RY(+) which has high esterase activity showed poor reproduction ability(0.8 progenies per $G_{1}$ individual than substrain O-RY(-) (3.4 progenies per $G_{1}$ individual) which has low esterase activity at $28^{\circ}C$

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.54-60
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• 2008

Deactivation of SCR catalyst applied in Orimusion fuel power plant was investigated to develope the technique for the regeneration of deactivated SCR catalyst and optimize the operation of SCR facility. The characterization study of the catalysts was carried out using XRD, ICP-AES, SEM and EDS. The NO$_X$ removal activity and SO$_2$ oxidation activity of the catalysts were measured. The NO$_X$ conversion of the deactivated catalyst was 5$\sim$10% lower than that of the fresh catalyst and the value of SO$_2$conversion to SO$_3$ over the deactivated catalyst was about 0.59% higher than that of the fresh catalyst. Vanadium(V), Magnesium(Mg) and Sulfur(S) were largely accumulated in the deactivated catalyst. The accumulation of Vanadium(V) and Sulfur(S) is due to the components of the Orimulsion fuel and the accumulation of Magnesium(Mg) is due to MgO that is injected in the boiler to prevent the oxidation of SO$_2$ to SO$_3$. The diffraction line of the TiO$_2$ of the deactivated catalyst was identified as the crystalline peaks of anatase as the fresh catalyst.

• Korean Journal of Environmental Agriculture
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• v.9 no.2
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• pp.153-159
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• 1990

Two fractions(microsomal and soluble) were prepared by ultracentrifugation(105,000G for 1hr at $4^{\circ}C$) from pig liver in order to find the major factor in Diazinon degradation. The two enzyme activities showed the same value, but Diazinon was degraded three times in microsomal fraction more than in soluble fraction. And with addition of EPN, Beam and PBO, degradation of diazinon was inhibited(29, 30 and 60%) as well as Monooxygenase activity (14, 15 and 35%) in microsomal fraction, respectively.

• Journal of the Korean Ceramic Society
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• v.42 no.1
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• pp.22-27
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• 2005

The preparation of B4C by SHS in $B_{2}O_{3}-Mg-C$ system was investigated in this study. In the preparation of B4C, the effect on reactivity and reaction products of the initial pressure of inert gas in reactor, the content of Mg and C in mixture was investigated. The minimum initial pressure of inert gas in reactor for SHS reaction in this system was 25 atm, and as the pressure increased, the concentration of unreacted Mg decreased and combustion temperature increased. At the initial inert gas pressure in reactor of 25 atm, the optimum composition for the preparation of pure B4C was $2B_{2}O_{3}+6.3Mg +0.94C$. The B4C synthesized in this condition had an irregular shape and the particle size of $1\~3{\mu}m$.

• The Korean Journal of Food And Nutrition
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• v.18 no.1
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• pp.39-47
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• 2005

Using the bacteria isolated from Chungkookjang, Bacillus sublilis MG410 which is excellent in fibrinolytic enzyme activity was isolated. In increase the high production of fibrinolytic enzyme from Bacillus sublilis MG410, the effect of various carbon sources, nitrogen sources, inorganic sources, the initial pH of medium were investigated. The most effective carbon and nitrogen sources were founded cellobiose 0.5%(w/v) and soybean meal 2%(w/v) respectively. None of inorganic sources examined had any detectable stimulating effect on fibrinolytic enzyme production except Na₂HPO₄·12H₂O. The initial optimum pH for fibrinolytic enzyme production ranged from 5∼6 and agitation speed was effect at 150rpm. In jar fermentor experiments under optimal culture conditions, the activity of fibrinolytic enzyme reached about 5.050 unit after 48hours.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.463-466
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• 2000

In this study, it was observed to oxygen uptake rate(OUR) on microbes in activated sludge process. OUR was showed to 43, 55, and $64\;mgO_2/L/hr$ when inoculated microbes mass were 3, 5, and 10%(v/v%). In additon to oxygen was consumed to $4{\sim}42\;mgO_2/L/hr$ as changed substrate concentration. Also, we were measured kinetics coefficient in order to know growth tendency. It was concluded to maximum growth rate$(\;{\mu}\;_{max})$, $2.7\;day^{-1}$, yield coefficient, 0.655, and half-velocity coefficient, 36.11 mg/L.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.275-280
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• 2011

In the present work, the aerobic particle's characteristics were enhanced. A polymer was used to make aerobic granular sludge in short period of time. And operation parameters were calculated for organic matter removal in domestic wastewater using a sequencing batch reactor (SBR). The experiment for sewage (Influent concentration of 63~72 mg COD/L) by using mature aerobic granular sludge showed the organic matter removal rate k and oxygen utilization coefficient a', b' were $10.161d^{-1}$ and 0.87 mg $O_2/mg$ $COD_r$, 0.11 mg $O_2/mg$ MLVSS d respectively. Therefore, it was more effective than K value $5{\sim}8d^{-1}$ of conventional activated sludge process. The sludge synthetic value and sludge auto-oxydation value were 0.45 mg VSS/mg $COD_r$ and 0.05 mg VSS/mg MLVSS d respectively. Consequently, mortality rates of microorganisms was lower than conventional activated sludge process.