• Journal of Environmental Science International
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• v.7 no.4
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• pp.493-500
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• 1998

An experimental study was conducted to Indentify the dlrpct denitrification of ammonium nitrogen In culture water by ozone. During the experimnet period, pH was 7.8-8.8. pH was grdually lower after ammonium nitrogen was reacted with ozone under Br . In addition, it can be tmown that the culturing water was improved greatly form the inverstigation of T-N by biofilm and ozonation. As the results of a variation of recirculation rate, denitrification of ammonium nitrogen was in increased in proportion to the recirculation rate. But Nitrification of microorganism was opposite to the recirculation rate. With the increasing injected ozone in ozonation tank uner 21 clrculation/day(6.71 /min), dinitrification of ammonium nitrogen was Increased lineraly in propotion to the Increasing of injected ozone concentration.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.1
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• pp.17-28
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• 2008

The wood-pulp is treated with the three enzymes; Endo-xylanase, exo-xylanase and acetyl-esterase. The maximum value of relative activity appeared 0.95 in acetyl-esterase at $40^{\circ}C$, 0.9 in exo-xylanase at $40^{\circ}C$, and 0.8 in endo-xylanase at $50^{\circ}C$, respectively. And it has measured 0.8 in endo-xylanase, 0.95 in acetyl-esterase at pH 6 and 0.9 in exo-xylanase at pH 5, while the maximum value of relative activity does not rely on reaction time for three enzymes treatment, and the value was about 0.9, respectively. We have watched that decreased Kappa number and increased brightness. And it turned out that the three enzyme produced a lot of reducing sugar with wood-pulp treatment.

• Journal of the Korean Chemical Society
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• v.9 no.1
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• pp.41-44
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• 1965

The properties of Fe(II)-7-nitrose-8-hydroxyquinoline-5-sulfonate have been studied spectrophotometrically at 700$m{\mu}$, $26^{\circ}C$. The absorbance of the complex shows a maximum at pH 6.0 and good thermal stability. Excess of the ligand and the reducing agent do not interfere the formation of the complex. The composition of the complex is found to be 3:1 ligand to metal species by molar ratio and continues variation methods. Calibration curve follow Beer's law over the range of concentratiion studied.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.115-118
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• 1998

Utilization of yeast extract and formation of byproduct metabolite were investigated for hyperthermophilic archaeon Sulfolobus solfataricus (DSH 1617). In both batch and fed-batch cultivations of S. solfataricus, maximal cell density, {{{{ { NH}`_{4 } ^{ +} }}} ion production and pH change were highly dependent on the ratio of yeast extract to glucose in the medium. Variation of {{{{ { NH}`_{4 } ^{ +} }}}} ion level was identified as a major cause of pH change during cultivation, and acidification of culture broth was attributed to consumption of {{{{ { NH}`_{4 } ^{ +} }}}} ions rather than formation of acid byproducts. It was also observed that increase of {{{{ { NH}`_{4 } ^{ +} }}}} ion concentrations in the medium resulted in greater degree of growth inhibition.

• The Korean Journal of Ceramics
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• v.3 no.4
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• pp.235-238
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• 1997

Basic properties of new cement pastes based on the system $CaO-Al_2O_3-P_O_5-H_2O$were studied Phosphoric acid solutions and calcium dialuminate clinkers synthesized by the hydration-burning method were used for liquid and powder components of the paste, respectively Variation in the compositions of the paste was achieved by changing the liquid/powder ratio and the concentration of phosphoric acid solution. The hardening rate of the paste was so largely affected by the amount of phosphoric acid that hardening was inhibited with the low-concentrated solution but was explosively accelerated with the high-concentrated solution. The phosphoric acid solutions of concentration of 45~50% and the liquid/powder ratio of 0.5~1.5 were favoured for the high early-strength cement paste with the reasonable hardening rate and high strength. The binding phase of hardened paste was the dense amorphous gel of the system $CaO-Al_2O_3-P_O_5-H_2O$. in which the unreacted calcium dialuminate grains were embeded.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.192-195
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• 2003

The hight density sludge process (HDS) is a process that has been developed to achieve greatly increased sludge densities compared to those resulting from conventional pH modification systems. This study was carried out to apprehend variation of sludge properties and removal of metals during recycling of the sludge. The principal neutralization and settlement took place in neutralization beaker and mass cylinder. Sludge was recycled, as a volumetric ratios of 20%, 40% and 60%. The pH was controlled in neutralization tanks near 9.5. The average lime consumption rate was about 10g per L of AMD. The increment of sludge density was correlated with the volumetric ratios of recycled sludge.

• Journal of Fashion Business
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• v.22 no.3
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• pp.30-38
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• 2018

Glycolic acid(GA) is well known the most effective cosmetic ingredient on the epidermal remodeling, accelerated desquamation and inhibitory effect on melanin synthesis. The various cosmetic formulations containing GA have not been reported in terms of stability. This study was to investigate the stability of three formulations(gel, cream, and ointment). The stability of obtained formulations was tested chemical and physical characteristics including the composition stability, hot-cool cycling, the variation of pH and viscosity, and the observation of color and odor. The experimental results showed that the gel and cream containing 5% GA, both formulations have proper stability in the centrifugal test, hot-cool cycling test, viscosity, pH stability and the observation of color and odor. On the other hand, the 5% GA ointment did not have stability. We concluded that the formulations of gel and cream are more suitable than ointment to use GA ingredient for developing cosmetic in terms of stability.

• Journal of IKEEE
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• v.21 no.4
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• pp.375-380
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• 2017

A differential current-to-time interval converter is presented for current mode sensors. It consists of a ramp voltage generator, a current mode sensor, a reference current source, two current-tunable Schmitt triggers, a one-shot multivibrator, and two logic gates. The design principle is to apply a ramp voltage to each input of the two current-tunable Schmitt triggers whose threshold voltages are proportional to the drain current values of the current mode sensors. A proposed circuit converts a current change in the ISFET biosensor into its equivalent pulse width change. A prototype circuit built using TSMC 0.18 nm CMOS process exhibit a conversion sensitivity amounting to $726.9{\mu}s/pH$ over pH variation range of 2-12 and a linearity error less than ${\pm}0.05%$.

• Journal of the Korean Chemical Society
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• v.18 no.2
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• pp.132-137
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• 1974

Acid mucopolysaccharides were isolated from nucleus pulposus of whale embryo. The separation of acid mucopolysaccharides was most excellent in $0.03{\%}$ hexamine cobaltic chloride in 0.05 M-sodium acetate buffer solution at pH 4.8. Changes in electrophoretic mobility of acid mucopolysaccharides were observed when the sample solution on top of spacer gel were covered with $40{\%}$ sucrose solution. This effect was not observed by the addition of hexamine cobaltic chloride to the buffer solution.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.593-598
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• 2010

The optimum condition for fluoride removal, water content reduction, and $CaF_2$ purity was determined in treating semiconductor waste water in which ammonia nitrogen, phosphorus, and fluoride are existed simultaneously using a fluidized bed reactor. Effects of pH, seed dosage, and recirculation of treated water were investigated through lab-scale experiments. Considering fluoride removal, sludge purity, and water content, that pH 5 and seed dose of 150 g were found to be optimum. Correspondingly, removal of fluoride and phosphate (${PO_4}^{3-}$-P) was 94.24% and 8.97%, respectively, with water content ratio of 12.94%. Increase in an amount of seed dosage not only enhance fluoride removal efficiency, but also buffer fluoride removal-reducing effect due to the variation of recirculation ratio of treated water and pH.