• 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.

• Cement Symposium
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• no.16
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• pp.81-87
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• 1988

• Cement Symposium
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• s.35
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• pp.122-126
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• 2008

• KSBB Journal
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• v.14 no.3
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• pp.309-314
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• 1999

In order to produce high concentration of sodium gluconate, optimization of the fermentation conditions, such as glucose concentration, inoculum size, dissolved oxygen concentration and glucose feeding method, was examined. When the glucose concentration was maintained in the range of 30∼50 g/L during the batch fermentation, glucose conversion yield and productivity were 92.2% and 6.0 g/L/hr, respectively. In the case of the low concentration below 30 g/L, the yield decreased by about 25%. As the inoculum size increased above 20%(w/v), lag phase was shortened but the productivity decreased. The dissolved oxygen level of 60∼70% was shown to be the threshold point for 75% of increase in the productivity of sodium gluconate. Finally, optimal glucose feeding rate was determined using various feeding methods such as exponential feeding, feeding based on the average glucose consumption rate and was determined using various feeding methods such as exponential feeding, feeding based on the average glucose consumption rate and on the oxygen uptake rate and etc. Our result shows that glucose feeding, based on the oxygen uptake rate is a very simple, efficient and robust method, especially when oxygen is consumed as a substrate for the bioconversion. Using the above glucose feeding strategy under the optimized condition, 255 g/L of sodium gluconate concentration, 12 g/L/hr of productivity and 95% of glucose conversion yield were achieved with A. niger ACM53.

• 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.

• 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.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.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.

• KSBB Journal
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• v.13 no.2
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• pp.214-219
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• 1998

Polymerase chain reaction(PCR) was conducted to obtain the gene encoding glucose oxidase(GOD) from Aspergillus niger(ATCC 2110) and the DNA sequence determined was coincided with published GOD sequence from A. niger. Recombinant transforming vector containing GOD and hygromycin B(hyg.B) resistant gene(hph) was constructed and used for further transformation of A. niger ATCC 2110. Selectivity of hyg.B against A. niger differed depending on which media were used i.e., nutrient-rich media such as potato dextrose agar(PDA) and complete medium(CM) showed only 50% growth inhibition at 400 $\mu$m ml$^-1$ of hyg.B while the minimal media inhibited mycelial growth completely at 200 $\mu$m ml$^-1$ of hyg.B. Twenty to sixty putative transformants were isolated from the hyg.B-containing minimal top agar, transferred successively onto alternating selective and nonselective media for a mitotic stability of hyg.B resistance and, then, single-spored. Among the stable transformants, the transformant(GOD1-6) grown by flask culture showed the considerable increase of extracellular GOD activity, which was estimated to the degree of 50% - 100% comparing to that of wild type. Transformation of tGOD1-6 was resulted from integration of the vectors into heterologous as well as homologous regions of the A. niger genome. Southern blot analysis revealed that there were two independent integrations of vector into fungal genome and one into the GOD gene due to homologous recombination. In addition, GOD activity and sodium gluconate production when tGOD1-6 was fed-batch fermented were enhanced 11 fold and 2.25 fold, respectively, compared to that of the wild type.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.21-29
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• 2005

The HANARO, a multi-purpose research reactor of 30 MWth open-tank-in-pool type, has been under normal operation since its initial criticality in February, 1995. Recently, ten years after the initial operation of the HANARO, one of the two primary cooling pumps was decontaminated for overhaul maintenance in 2004. Before decontamination exposure doserate and surface contamination level of primary cooling pump measured at 4 points. After final decontamination exposure doserate and surface contamination level of primary cooling pump remeasured by same method done before. It is easy to decontaminate the out side exposed surfaces of the pump, but it is difficult to approach the inside surface due to double volute installed in the casing. Therefore, a new decontamination facility has been developed to solve this problem. A concentrated de-contaminant (DX-300) is rotated in the closed pump casing by the impeller actuated by a temporary motor. Nuclide particles are removed by the emulsification effect of the de-contaminant and the surface contaminants are chemically removed from the pump by the corrosion and dissolution effect. The inside surfaces of the primary cooling pump have been decontaminated by using the facility. As results, the contamination level of the inside surfaces was maintained below the surface contamination limit.