• The Korean Journal of Ceramics
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• v.2 no.2
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• pp.63-69
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• 1996

Barium titanyl oxalates, strontium titanyl oxalates and calcium zirconyl oxalates were prepared with variation of solution concentration and method of adding mixed metal ion solution into oxalic acid. Then they were aged in distilled water, ethanol or methanol, respectively. Barium titanyl oxalates and calcium zironyl oxalates were grown in water and strontium titanyl oxalates were groun in both water and methanol. They were supposed to be grown through the solutionl and reprecipitation mechanism. Nonuniform dispersion of particles in liquid phase is thought to cause abnormal particle growth.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.1
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• pp.134-139
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• 1999

This study was conducted to determine the effects of water aggressivity on the corrosion in a recirculating pipe loop systems. As the pH was increased in the range of pH 6.0~8.5, water aggressivity was decreased. Zine and iron concentration of water adjusted by pH were lower than those of tap water and water adjusted by alkalinity and calcium hardness. The major elements of corrosion deposit analyzed by EDS(Energy Dispersion Spectrophotometer) were zinc and calcium. In conclusion, we suggest that in corrosion control practice in the water works industry, increasing the pH of the water can serve as a way of controlling the solubility of metal ions release from water distribution systems.

• Korean Journal of Metals and Materials
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• v.50 no.11
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• pp.823-828
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• 2012

Direct reduction of $Ta_2O_5$ using liquid calcium was investigated. The experiment was conducted in a closed stainless steel chamber in an Ar atmosphere for 5-120 minutes. Most of $Ta_2O_5$ was reduced to ${\alpha}-Ta$ in 30 minutes above 1173 K and at a molar ratio of Ca and $Ta_2O_5$ above 10. The particles size increased with the reaction temperature, but it did not change much above 1223 K. The oxygen content of metal Ta was about 1 wt%.

• Membrane Journal
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• v.30 no.2
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• pp.97-110
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• 2020

CO₂ capture and storage (CCS) is one of the promising technologies that can mitigate ever-growing emission of anthropogenic carbon dioxide and resultant climate change. Among them, chemical looping combustion (CLC) and calcium looping (CaL) are getting increasing attention recently as the prospective alternatives to the existing amine scrubbing. Both methods use metal oxides in the process and consist of cyclic reactions. Yet, due to their cyclic nature, they both need to resolve sintering-induced cyclic stability deterioration. Moreover, the structure of the metal oxides needs to be optimized to enhance the overall performance of CO₂ capture and storage. Deposition of thin film coating on the metal oxide is another way to get rid of wear and tear during the sintering process. Chemical vapor deposition or atomic layer deposition are the well-known, established methods to form thin film membranes, which will be discussed in this review. Various effective recent developments on structural modification of metal oxide and incorporation of stabilizers for cyclic stability are also discussed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.2
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• pp.1-7
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• 2014

Causticizing calcium carbonate (CCC) is produced as a by-product in the causticization step of the kraft pulping process. It is often calcined in a rotary lime kiln after being dewatered and reused in the causticizing process. But for the China mill, the conventional recycled way is difficult because the CCC is mainly obtained from non-wood pulping materials, which higher silicon content led to serious silicon obstacle. So it is often discarded as solid waste or used in landfill after dewatering and secondary pollution is brought. In order to prevent its secondary pollution, recent years, the CCC is used as a filler in China papermaking industry. In mill trials, the CCC can be used to replace an amount of precipitated calcium carbonate (PCC). Unfortunately, the application scope and dosage of CCC have been limited due to its lower sizing efficiency than PCC. In this study, the reason for the lower sizing efficiency of alkyl ketene dimer (AKD) when CCC was used as a filler was investigated. The results showed that the materials in green liquid, such as insoluble matter in green liquid, silicon and metal ions, were a little influence on the sizing efficiency of AKD. The higher BET and BJH pore volume of the CCC were the main reason for lower sizing efficiency of AKD when it was used as filler.

• Bulletin of the Korean Chemical Society
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• v.27 no.6
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• pp.835-840
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• 2006

Dimethyl 1-(4-nitrobenzoyl)-8-oxo-2,8-dihydro-1H-pyrazolo[5,1-a]isoindole-2,3-dicarboxylate has been used as an ionophore and o-nitrophenyloctyl ether as a plasticizer in order to develop a poly(vinyl chloride)-based membrane electrode for calcium ion detection. The sensors exhibit significantly enhanced response towards calcium(II) ions over the concentration range $8.0{\times}10^{-7}\;1.0{\times}10^{-1}$ M at pH 3.0-11 with a lower detection limit of $5.0 {\times}10^{-7}$ M. The sensors display Nernstian slope of 29.5 ${\pm}$ 0.5 mV per decade for Ca(II) ions. Effects of plasticizers, lipophilic salts and various foreign common ions are tested. It has a fast response time within 10 s over the entire concentration range and can be used for at least 2 months without any divergence in potentials. The proposed electrode revealed good selectivity and response for $Ca^{2+}$ over a wide variety of other metal ions. The selectivity of the sensor is comparable with those reported for other such electrodes. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a Ca(II) solution, with EDTA.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.6
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• pp.279-285
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• 2012

The co-precipitation technique has been applied to synthesize Biphasic Calcium Phosphate (BCP), Mg-BCP and Si-BCP. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy were used to characterize the structure of synthesized BCP, Mg-BCP and Si-BCP powders. The results have shown that BCP and substitution of magnesium and silicon in the calcium deficient apatites revealed the formation of biphasic mixtures of Hydroxyapatite (HAp)/${\beta}$-Tricalcium phosphate (${\beta}$-TCP) ratios after heating at $1000^{\circ}C$. Ionic substituted BCP is able to develop a new apatite phase on the surface in contact with physiological fluids faster than BCP does. An MTT assay indicated that BCP, Mg-BCP, and Si-BCP powders had no cytotoxic effects on MG-63 cells, and that they have good biocompatibility.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3327-3333
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• 2011

The interest on the recovery of thermal energy using the industrial waste has been rising to solve the problems of continuous increase of waste generation and the depletion of the fossil fuel recently. To recovery from the waste among the new recyclable energies has been proved as the most favorable when the potential value of energy source is compared. The RDF made from the industrial waste has been approved as the most economical method. This research has analyzed the heavy metal components containing in the industrial waste. The concentration of Cl and S in the industrial waste generated in C-industrial complex are slightly high than that of the B- and A-industrial complex. The main components generated from A-industrial complex, B-industrial complex, and C-industrial complex are alumina-silicates, calcium alumina silicates, and the mixture of lime and calcium alumina silicate. These results could be used to reveal the origin of inorganic components in industrial waste and utilized as a basic data to improve the performance of the RDF as fuel.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.593-596
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• 2003

The special amendment agent used in this study is mainly composed of inorganic metal salts such as sodium chloride, magnesium chloride, potassium chloride, calcium chloride, thus is friendly to the environment, and has a function of soil-cement-agent solidification. In this study, a series of laboratory and field experiments including unconfined compressive strength, permeability, pH test, constituent analysis, leaching test were carried out to analyse engineering and environmental characteristics of solidified sludge. The results of this research showed that the solidified sludge could be efficiently used in covering, filling, and planting materials.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.425-426
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• 2003

산업의 발달과 생활수준의 향상으로 생활환경을 쾌적하게 하여 보다 나은 생활환경을 만들에 내는데 관심이 집중되고 있으며, 이와 관련된 의류용 섬유 분야에서는 미생물에 대한 저항성이나 악취, 땀냄새 등을 제거하는 섬유에 대한 관심이 높다. Calcium Hydroxyapatite(Ca$_{10}$(PO$_4$)$_{6}$(OH)$_2$, HAp)는 칼슘 포스페이트계 세라믹으로 우수한 생체친화력과 단백질 흡착능력을 지니고 있어, 골 대체용 재료나 단백질을 분리하는 크래마토그래피, 유전자 담채 둥에 이용된다.[1] (중략)략)