• Journal of the Korean Ceramic Society
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• v.23 no.6
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• pp.1-6
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• 1986

The hydration of $C_3A$ and $C_3A-CaSO_4$.$2H_2O$ was investigated with varying concentration (0.1-1.0%) of sodium gluconate solution. gluconate solution. Sodium gluconate accelerates cation dissolution from $C_3A$ for the first several minutes but depresses the rate of heat evolution in the course of $C_3A$ hydration. The hydration of $C_3A$ in the presence of sodium gluconate was modified such that the formation of the intermediate hydrate C4AH$\chi$ crystal was much reduced and most of the product became amorphous. The retardation of $C_3A-CaSO_4$.$2H_2O$ hydration in the presence of sodium gluconate was controlled by the competitive adsorption between gluconate anion and $SO_4^{-2}$ onto $C_3A$ surface.

• Journal of the Korean Ceramic Society
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• v.23 no.2
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• pp.38-42
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• 1986

The adsorption behavior of 3CaO.$Al_2O_3$-sodium gluconate-$H_2O$ system by measuring adsorp-tion isotherm DTA and IR sepctra. The adsorbed amount of sodium gluconate on 3CaO.$Al_2O_3$ is exceedingly larger than 3CaO.$SiO_2$ and portland cement. From the DAT experiment the formation of complex is observed by the characteristic exothermic peak of the complex at 45$0^{\circ}C$ It is now strong deduced that the chemical bonding between gluconate anion and 3CaO.$Al_2O_3$ should be coordinative due to the complex formation on the surface 3CaO.$Al_2O_3$ from the IR spectra of sod-ium gluconate only and 3CaO.$Al_2O_3$ -sodium gluconate-$H_2O$.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.883-890
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• 1990

Although various theories have been presented on the mechanism of setting retardation of 3CaO·Al2O3, this phenomenon has not yet been defined. The present investigation was initiated in order to solve the mechanism from the view point of coordination chemistry. The solubility of Ca(OH)2 in aquous solution of soldium gluconate was abnormally high, and was proportional to the concentration of sodium gluconate. These phenomena were attributed to the soluble complex formation, that is, (1 : 1)Ca complex formation between calcium ion and gluconate ion. The author's proposal was further confirmed by the results of electrical conductivity measurement. The formation of calcium complex was also supported by IR spectra and DTA. When sodium gluconate was dissolved in 3CaO·Al2O3 suspension, calcium complex and aluminum complex were formed. As an experimental evidence, the asymmetric stretching vibration of carboxyl group in sodium gluconate was observed to be shifted to lower frequency from 1625cm-1 to 1585cm-1 characteristically. The characteristic exothermic peaks of the complexs at 430℃ and 700℃ observed in DTA curve also suggest the formation of the complexs between sodium gluconate and 3CaO·Al2O3.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.24-29
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• 1996

The purpose of this study is to propose new estimation method of unit cement content in hardened concrete. In general, the quantity of cement in hardened concrete is tested by hydrochlonic acid dissolving cement paste, however, hydrochloric acid dissolves sea shell contained in sea sand and lime stone in concrete. Therefore, the tested cement content is apt to estimate greater than actual cement content. The sodium gluconate solution dissolves only cement in concrete, it is hard to dissolve sea shell and lime stone as CaCo3. The effects of the quantity, concentration and temperature of sodium gluconate solution, the ignition temperature, the ignition loss of cement on the cement content and the percentage of dissolution of cement were investigated to establish a test method. From the results of these tests, the fundamental test method for cement content of hardened concrete by sodium gluconate is proposed.

• KSBB Journal
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• v.11 no.1
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• pp.65-70
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• 1996

Sodium gluconate was produced by neutralization of gluconic acid formed during the submerged culture fermentation of glucose with Aspergillus niger ACM 7. The fermentation characteristics of Aspergillus niger ACM 7 were investigated quantitatively according to the change of the initial glucose concentrations and the initial pHs of fermentation broth. The maximum specific growth rate was estimated to be $0.20hr^{-1}$ at 95g/$\ell$ of initial glucose concentration. The maximum fermentability of sodium gluconate was 95% at the initial glucose concentration of 26g/$\ell$. However, the maximum sodium gluconate productivity was 1.18g/$\ell$/hr when the initial glucose concentration was 110g/$\ell$. The optimum pH was found to be 5.5 for both the cell growth and the sodium gluconate production. With optimized culture conditions, the productivity of sodium gluconate in a fed-batch culture(production fermentor, 16,000$\ell$) increased up to 7.1g/$\ell$/hr.

• Journal of the Korean Ceramic Society
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• v.24 no.3
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• pp.289-295
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• 1987

The changes of physical properties of portland cement pastes and mortars were investigated by addition of sodium gluconate. Flow table experiment and viscosity measurement were took in order to find dispersing effect, and time-dependent changesof viscosity and rates of hydration heat evolution were carried out for the sake of finding retardation effect of hydration. And changes of physical properties of cement pastes and mortars were discussed by setting time, compressive strength and porosity.

• Advances in Computational Design
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• v.1 no.1
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• pp.27-35
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• 2016

The influences of chloride-free components of the cement additive: triethanolamine, triisopropanolamine, sodium hyposulfite and calcium gluconate on the 1d, 3d and 28d compressive strength of cement were investigated by response surface methodology. It found the early strength activators, triethanolamine and sodium hyposulfite could enhance the 1d strength of cement effectively but they did not contribute to the 3d strength enhancement, and further their interaction was able to decrease the 28d strength of cement. Calcium gluconate was not that effective for the strength enhancement on 3 and 28 days when it's simply dosed. However the interaction effect of calcium gluconate with triisopropanolamine could strongly favor the strength enhancement of cement after 3 days. Results indicated it was necessary to focus attention on the potential interactions among the chemical components. And for the concern of four chemicals studied in this paper, it was feasible to formulated a kind of chloride-free cement additive that can be effective for the early strength of cement and its the strength after 3 days.

• Journal of Electrochemical Science and Technology
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• v.10 no.3
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• pp.257-270
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• 2019

The inhibition performance of sodium gluconate (SG), cetyltrimethylammonium bromide (CTAB) and their mixture (SG/CTAB) on the corrosion behavior of ${\alpha}$-brass in 0.5 M $H_2SO_4$ solution has been investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS), Inductively Coupled Plasma Spectrometry (ICPS) and molecular dynamics (MD) simulation techniques. The results reveal that SG with 5ppm CTAB, noted SG/CTAB, acts as a good corrosion inhibitor and its inhibition efficiency reached 89% after 24 h immersion in sulfuric acid solution, but slightly decreased at higher temperatures. The polarization curves displayed that SG/CTAB acts as a cathodic-kind inhibitor. Electrochemical impedance spectroscopy (EIS) studies revealed that the addition of 5ppm CTAB to different concentrations of SG considerably increases the corrosion resistance of ${\alpha}$-brass. The SEM-EDS and ICPS analyses support the experimental results. Further, molecular dynamics (MD) simulations were used to understand the adsorption profiles of SG/CTAB on Cu(111) and Zn(111) surfaces.

• Korean Journal of Metals and Materials
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• v.46 no.11
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• pp.725-729
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• 2008

Deposition characteristics of electroless plated Ni-W-P films were investigated for various complexing agents. Used complexing agents are sodium citrate, sodium gluconate and sodium malonate. In this study, the existing mixed potential theory could explain the overall mechanism of Ni-W-P electroless plating for all complexing agents. The deposition rate could be also expected by the theory. The deposited Ni-W-P films were evaluated in term of surface hardness and corrosion resistance. Microhardness of the deposit increased about 1,000 Hv after heat treatment for one hour at $400^{\circ}C$, because it was above the crystallization temperature of $Ni_3P$. The deposited Ni-W-P films can exhibit excellent corrosion resistance in using sodium malonate as a complexing agent, the other hand the using sodium gluconate was the worst corrosion resistance. The worst corrosion resistance was due to a large number of nano-sized pin-holes or small pores. The plating current at the mixed potential increases when the using sodium malonate as a complexing agent, it was explained by the cross section.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.329-335
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• 1995

Rheological properties of whole soybean gel(soygel) were investigated as affected by the water addition ratio, stirring time and Ca salts. The soygel was prepared by suspension of whole soy flour(WSF, 300 mesh) in boiling water, addition of sodium alginate and Ca salts followed by thorough mixing and gel formation at $4^{\circ}C$. The texture properties of hardness, adhesiveness and cohesiveness of the gel were increased as the stirring time prolonged from 5 to 30 minutes. From the results of the rheological and sensory properties, 20 minutes of stirring time was selected for whole soybean gel preparation. Eventhough increase in water addition ratio from 8 to 12 times(water/WSF, v/w) resulted a decrease in hardness and adhesiveness, 10 times ratio was chosen as proper the water addition based on textural uniformity. Among the Ca salts, $CaSO_4$ produced the highest hardness followed by Ca $gluconate-CaSO_4$ mixture(413g) and Ca gluconate at the water addition level of 10 times. In order to determine the amounts of Ca salts, and 0.125g of Ca gluconate or $CaSO_4$ per g WSF were found to be optimum in terms of textural and sensory properties. The proper mixing ratio of Ca gluconate and $CaSO_4$ was found to be 50 : 50, 25 : 75 and 0 : 100.