• Journal of the Korean Ceramic Society
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• v.28 no.4
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• pp.338-346
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• 1991

The alumina-titania composite powders coated with Al2O3 were prepared by the method of hydrolysis-deposition of mixed aluminium salt solution of Al2(SO)4-Al(NO3)3-Urea. The effects of coating-process parameters on the characteristics of coated composite powders were also investigated. As the content of TiO2 dispersed in deionized water increased, the coated composite powders were found to be more uniform in size and unagglomerated. When TiO2 powders were coated for 30 min, the optimum TiO2 content in the coating process was 400 mg/ι. The size of TiO2 particle was increased approximately from 0.7${\mu}{\textrm}{m}$ to 1.0${\mu}{\textrm}{m}$ through coating of Al2O3. The IEP of coated composite powders was pH=8.3 identical to the value of aluminium hydroxides and the zeta-potential showed nearly similar values each other. When heat treating coated composite powders at 130$0^{\circ}C$, only two phases of TiO2(rutile) and Al2TiO5 were observed. These results showed that the suface of TiO2 could be uniformly coated with the aluminium hydroxide.

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.272-278
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• 2013

Extract of ginger has been evaluated as a green inhibitor for the corrosion of steel in sulfide polluted NaCl solution using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. Potentiodynamic polarization measurements showed that this extract acts as a mixed type inhibitor but mainly inhibits the cathodic reaction. The inhibition efficiency was found to increase with inhibitor concentration reaching to approximately 83.9% using 250 ppm of ginger. Nyquist plots show a single capacitive loop in uninhibited and inhibited solutions. From EFM the causality factors are very close to theoretical values which indicate that the measured data are of good quality. The adsorption process of the studied extract on steel surface obeys Temkin adsorption isotherm. The results obtained from the different electrochemical techniques were in good agreement which prove the validity of these tools in measurement of corrosion rate. Ginger extract has no effect on Escherichia Coli and can be applied safely on waste water treatment plants.

• Bulletin of the Korean Chemical Society
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• v.15 no.7
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• pp.541-545
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• 1994

A series of samples of the ${Ca_xEu_{1-x}FeO_{3-y}$ (x=0.00, 0.25, 0.50, 0.75, and 1.00) system has been prepared at $1,250^{\circ}C$ under an atmospheric air pressure. X-ray diffraction analysis of the solid solution assigns the structure of the compositions of x=0.00, 0.25, 0.50, and 0.75 to the orthoferrite-type orthorhombic system, and that of x=1.00 to the brownmillerite-type orthorhombic one. The mole ratios of $Fe^{4+}$ ion in the solid solutions or ${\tau}$ values were determined by the Mohr's salt analysis and nonstoichiometric chemical formulas of the system were formulated from x, ${\tau}$, and y values. From the result of the Mossbauer spectroscopy, the coordination and magnetic property of the iron ion are discussed. The electrical conductivities are measured as a function of temperature. The activation energy is minimum at the composition of x=0.25. The conduction mechanism can be explained by the hopping of electrons between the mixed valences of $Fe^{3+}\;and\;Fe^{4+}$ ions.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.15-21
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• 1993

Crude ${\beta}-glucan$ extracted from Barley was purified by stepwise enzyme treatment (Thermostable ${\alpha}-amylase$, amyloglucosidase, protease). The Intrinsic Viscosity $[{\eta}]$ of the purified ${\beta}-glucan$ was determined by Cannon Fenske Capillary Viscometer (size 50, Cannon Instruments, State, College pa.) at different pH (2, 4, 7, 9, 11) and various salt concentration (0.01 M, 0.03 M, 0.05 M, 0.07 M, 0.1 M and 0.2 M). The $[{\eta}]$ of purified ${\beta}-glucan$ was ranged from $0.997{\sim}2.290\;dl/g$. The $[{\eta}]$ of purified ${\beta}-glucan$ at both alkali, acid condition were lower than those at pH 7. However, the alkali condition of puified ${\beta}-glucan$ solution showed less $[{\eta}]$ than the acid condition of this solution. From 0 M to 0.2 M salt concentration, the $[{\eta}]$ of purified ${\beta}-glucan$ solution was decreased to 0.03 M then increased to 0.05 M NaCl and remained constant to 0.2 M NaCl. The chain stiffness parameter of purified ${\beta}-glucan$ was not affected by temperature from $15^{\circ}C$ to $65^{\circ}C$. The shear rates of various ${\beta}-glucan$ conditions were determined by Bohlin Rheometer (Lund, Sweden). The ${\beta}-glucan$ concentration of 1.0 g/dl and 2.0 g/dl behaved as Newtonian fluid. However, above the concentration of 3.0 g/dl ${\beta}-glucan$ solution, it showed thixotropic and psedoplastic characteristics. Barley ${\beta}-glucan$ appears a damping at 0.5 frequency for the 4.0 g/dl solution. Below 0.5 frequency, it appears a viscous behavior property and above 0.5 frequency, it appears a elastic behavior property.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.2
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• pp.136-143
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• 2013

In the sewage structures and wastewater facilities, concrete is exposed to hydrogen sulfide ($H_2S$) which acts as an acid material in a solution, and a strongly acidic sulfate ion ($SO{_4}^{-2}$) is generated by a sulfuric bacteria. Hence, a degradation of concrete with biochemical corrosion would be accelerated. Finally, durability of concrete and concrete structures may be greatly reduced. In this study, in order to remove the hydrogen sulfide which is used by the sulfuric bacteria organic-biologically, the antibiotic metal and metallic salt powders were mixed to concrete, and a suppressing performance of the sulfate ion was assessed. For the sulfuric acid bacteria, a comparative evaluation of antimicrobial performance on neutralized concrete specimens were carried out, also by a rapid chloride penetration test, chloride penetration depths and diffusion coefficients were measured for antibiotic concrete in accordance with the amount of metal and metallic salt-based antibacterial agents. Eventually, by an observation of the biochemical state of the surface of concrete specimens exposed outdoors, the performance and applicability of antibiotic concrete were confirmed.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.43-57
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• 1977

In order to establish methods of potato processing for mixed cooking with rice as main diet, treatment for polyphenol oxidase inactivation in potato tissues, and safety in regard to sanitation were studied. The results were summarized as follows: 1. Cut potato granule which were blanched in boiling water are practical and best in color within $3{\sim}6\;minutes$ dipping. 2. Dipping treatment of potato granules in a saline solution is not pratical because of the resulting color and saline taste. 3. Dipping treatment of potato granules in a boiling saline solution is not practical because of residual salt. 4. Dipping treatment of potato granules in low concentration of hydrochloric acid solution is not effective in color changes but dipping treatment from 0.1N concentration for 4-10 minutes to 0.5N concentration for $1{\sim}10minutes$ shows good effects. 5. Dipping treatment in boiling hydrochloric acid solution of 0.04-0.068N concentration for 3-5 minutes dipping is practical for its resulting color. 6. Dipping treatments in 0.05% of $K_2S_20_5$ solution for $50{\sim}60\;minutes$ and in 0.06% for $40{\sim}60\;minutes$ and 0.065% for $10{\sim}60\;minutes$ shows a small palatability in color but its boiled potato granules shows good color 7. Treatments for any time in $0.01{\sim}0.03%$ of boiling $K_2K_20_5$ solution after predipping in its cold solution for longer time than 30minutes show effective in the color and palatability of the potato granules and their cooked ones. 8. From the view of food sanitation, dipping treatment of the potato granules in the solution of $K_2S_20_5$ is safe because of the few residual amount of $SO_2$. 9. All the methods of treatment that potato granules are dipped for any time at 0.01% of $K_2S_20_5$ solution are safe from the view of fond sanitation. At 0.03% of $K_2S_20_5$ solution, nothing but the methods of treatment that they are dipped within 30 minutes and boiled within 4 minutes are safe.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.2
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• pp.92-98
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• 2012

The co-precipitation technique has been applied to synthesize biphasic calcium phosphate (BCP). $Ca(NO_3)_2{\cdot}4H_2O$, $(NH_4)_2HPO_4$, TEOS and $Mg(NO_3)_2{\cdot}6H_2O$ as the starting materials was used. After the heat treatment of powder crystalline phases HAp and ${\beta}$-TCP analysis showed a mixed phase. The overall spectra appear to have mainly two modes corresponding to characteristic $PO^{3-}_4$ and $OH^-$ groups. After immersion in Hanks' Balanced Salt Solution (HBSS) for 1 week a precipitation started to be formed with individual small granules on the specimen surface. An MTT assay indicated that ionic substituted BCP powders had no cytotoxic effects on MG-63 cells, and that they have good biocompatibility.

• Membrane Journal
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• v.25 no.6
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• pp.496-502
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• 2015

Facilitated transport is one of the possible solutions to simultaneously improve permeability and selectivity, which is challenging in conventional polymer-based membranes. Olefin/paraffin separation using facilitated transport membrane has received much attention as an alternative solution to the conventional distillation process. Herein, we report olefin separation composite membranes based on the polymer blends containing $AgBF_4/Al(NO_3)_3$ mixed salts. Free radical polymerization process was used to synthesize an amphiphilic graft copolymer of poly(dimethyl siloxane)-graft- poly(ethylene glycol) methyl ether methacrylate (PDMS-g-POEM). In addition, poly(ethylene oxide) (PEO) was introduced to the PDMS-g-POEM graft copolymer to form polymer blends with various ratios. The propylene/propane mixed-gas selectivity and permeance reached up to 5.6 and 10.05 GPU, respectively, when the PEO loading was 70 wt% in polymer blend. The improvement of olefin separation performance was attributed to the olefin facilitating silver ions as well as the highly permeable blend matrix. The stabilization of silver ions in the composite membrane was achieved through the introduction of $Al(NO_3)_3$ which suppressed the reduction of silver ions to silver particles.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.947-953
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• 2017

In this study, the regeneration efficiency of the amino acid salt absorbent which can be applied to carbon dioxide absorption / regeneration process was confirmed. The regeneration efficiency has a great influence on the economical judgment of the process. so, continuous regeneration experiment was conducted to establish economical process. The amino acid salts used in the experiments are Potassium L-lysinate and Potassium L-alaninate. Each amino acid and potassium hydroxide(KOH) were mixed at a 1: 2 molar ratio. In order to confirm the regeneration efficiency of the absorbent, carbon dioxide was absorbed in the two materials, and the carbon dioxide desorption experiment was carried out by heating. The initial reaction rate was L-alanine was faster. Over time, L-lysine, desorption higher concentrations of carbon dioxide. L-lysine showed higher regeneration efficiency than L-alanine, (L-alanine 47.26% and L-lysine 62.11%). As a result of the continuous regeneration experiment using the L-lysine having good absorption and regeneration efficiency, it was confirmed that the regeneration efficiency decreases as the number of regeneration increases.

• Food Science and Preservation
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• v.13 no.6
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• pp.686-690
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• 2006

Quality properties of legumes (Seoritae and red bean) with soaking of 3% NaCl solution and microwave dying were evaluated. The samples were soaking with 3% NaCl at $25^{\circ}C$ for 6 hr(Seoritae) and 12 hr(red bean). Moisture content of Seoritae and red bean after soaking are 35.8%, and 35.1% respectively. The samples were dried with microwave treatment and cooling with microwave treatment combination secondly to $12{\sim}14%$ for moisture content Hardness of Seoritae was decreased from $12,863g_f$ to $3,309g_f$. There was a difference between varieties on color value. Hardness of cooked rice with ratio of milled rice and legumes(7:3) was $3,165g_f$ which is lower value compared to regular cooked mixed rice. Sensory evaluation of cooked mixed rice showed that treated samples have higher scores on color, flavor, taste, texture and overall acceptability values than those of control.