• Journal of the Korean GEO-environmental Society
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• v.11 no.9
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• pp.39-45
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• 2010

Controlled low strength material(CLSM) is produced by mixing portland cement, fine aggregates, water and chemical admixtures. Sand is the most commonly used as the fine aggregates in the conventional CLSM. It is getting more and more difficult to obtain sand in Korea so it is required that the alternative materials be developed as the replacement of sand. Since the engineering characteristics of coal ash are similar to the sand, it becomes necessary to examine the application of the coal ash as the alternative material for CLSM and as the environment-friendly material. When the results meet the optimum pH level that plants can live, it can be expanded the scale of application of the study on the plant as the important field. This study was subjected to present the method to reduce the pH range of CLSM to a suitable condition that plants can survive. To verify this method, the care of neutralization was conducted by immersing the specimen to Ammonium monohydrogen phosphate. Before curing and neutralization, the maximum pH of developmental CLSM is approximately 11. However, the pH value of developmental CLSM has under 9.5 after peaceful curing and neutralization management.

• Polymer(Korea)
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• v.24 no.6
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• pp.886-892
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• 2000

Poly(4-vinyl phenol) (PVPh) was neutralized by LiOH and PVPh ionomers (PVPh-Li) with different Li neutralization extents were synthesized. The variation in $T_{g}$ with Li neutralization was determined by DSC and the results show that the $T_{g}$ increases by 3.$8^{\circ}C$ per Li mol%. When comparing this result with the 3.$2^{\circ}C$ per Na mol% reported for poly (styrene-co-hydroxy styrene), the greater value for PVPh-Li may be due to a strong interaction between unneutralized free -OH and -OLi produced. No distinct small angle X-ray scattering (SAXS) peak was observed for these PVPh ionomers in bulk. In the 50/50 blend of PVPh-Li with PVPh, the miscibile blend was obtained when the Li neutralization in PVPh-Li was 10 mol%. On the contrary, the 50/50 PVPh-Li/PMMA was immiscible when the Li neutralization was 5 mol%. It can be concluded that, even if the starting blend is miscible owing to hydrogen bonding, the miscibility of blend becomes diminished by introducing small amount of ion groups into one of the constituent polymers and the blend can be immiscible as long as any new strong intermolecular ion-dipole interaction is not generated.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.04a
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• pp.326-327
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• 2006

• Phonetics and Speech Sciences
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• v.1 no.1
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• pp.47-52
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• 2009

The speech of Sino-Korean has been evolved from geopolitical cause since 1945. The aim of this study is to collect Yanji dialectal speech and to compare with South Korean dialectal speech. Twenty Yanbian university students participated as informants. Acoustic speech informations are analyzed using the Multi-Speech Windows Vista version. Dialectal speech characteristics of Yanji sino-Korean showed posterior vowel /${\alpha}$/, neutralization of mid-vowel /o/ between /o/ and /Ɔ/. Lenis stop sound showed the tendency of glottalization based on VOT value. Sibilant sound contains aspiration following constriction and lateral /l/ realized the approximant /r/.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.333-340
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• 2019

Red mud is an industrial by-product produced during the manufacturing aluminum hydroxide (Al(OH)3) and aluminum oxide(Al2O3) from Bauxite ores. In Korea, aproximately 2 tons of red mud in a sludge form with 50% moisture content is produced when 1ton of Al2O3 is produced through the Bayer process. Neutralization of red mud will help to reduce the environmental impact caused due to its storage and also lessen significantly the ongoing management of the deposits after closure. It will also open opportunities for re-use of the residue which to date have been prevented because of the high pH. Moreover, attention to liquefied red mud(LRM) that does not require heating and grinding process for recycling is needed. In this paper, characteristics of compressive strength for cement paste with content of LRM neutralized by nitric acid and sulfuric acid. The results showed that compressive strength of cement paste with neutralized LRM is higher than that of cement paste with LRM.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.71-75
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• 1998

The objective of this study is to investigate geochemical characteristics of mine wastes including tailings in various abandoned mines in Korea. Tailings and wastes were sampled in and around 39 metalliferous mines, and analysed heavy metal concentrations including Cd, Cu, Pb and Zn extracted by 0.1N HCl and aqua regia by Atomic Absorption Spectrometry. Measurements of paste pH and lime requirement were carried out to examine a general geochemical characteristics of the materials. Lots of mine wastes were characterized by very low pH values of 2 to 4 and high lime requirement to control neutralization of the wastes. In addition, elevated levels of heavy metals were found in various mine wastes extracted by both 0.lN HCl and aqua regia. Because the mine wastes can be dispersed into the downstream by clastic movement and wind-blow, it is necessary to control the materials with a proper method for their reclamation.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.275-275
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• 2006

A series of organoboron polymer electrolytes were prepared and their ion conductive characteristics was investigated in detail. Alkylborane type polymer electrolytes prepared by hydroboration polymerization exhibited improve lithium transference number due to efficient anion trapping of alkylborane unit. A lithium borate type polymer/salt hybrid was also successfully prepared by dehydrocoupling polymerization of lithium mesitylhydrorate. Ionic conductivity of single ion conductive polymer/salt hybrid was further improved in the case of comb like polymer/boron stabilized imido anion hybrid prepared via polymer reaction of poly(organoboron halide) with hexylamine and PEO monomethylether and subsequent neutralization with lithium hydride.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.559-564
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• 2001

A method for calculating the main characteristics of a potentiometric titration curve in a carboxylic ion exchanger has been investigated. The potentiometric titration curves of simple electrolyte and ion exchangers (polyelectrolytes) showed a great difference between them. The acidity parameters of the ion exchangers, the thermodynamic constant (pK0), apparent equilibrium constant (K), and correction for the apparent equilibrium constant (b), were introduced and used to express the characteristics of the carboxylic ion exchanger. A characteristic equation related to the acidity parameters of the ion exchangers systems was derived. A fibrous carboxylic cation exchanger was used and potentiometric titration curves at different concentrations of the supporting electrolyte were obtained . To prove the validity of the characteristic equation, the concentration of the supporting electroyte was varied. In the present study, good agreement between the data points and the fitted curves was found in all the cases. The g (number of moles of alkali to 1 g of ion exchanger) of carboxylic ion exchanger was calculated from the concentration of supporting electrolyte (C), pH of the solution, and degree of neutralization of ion exchanger (x).

• Journal of the Korean GEO-environmental Society
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• v.23 no.9
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• pp.33-40
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• 2022

Sedimentation and pH neutralization has been investigated as preteatment of acid contaminate water. The settling and neutralizing process derive more effective degradation efficiency as the pre-treatment process before the removal process of adsorption, volatile, biodegradation, or oxidation. Settling velocity, uniformity coefficient, coefficient of curvature, and grain size index can define in the sedimentation process for characteristics of the soil. The stainless steel sieve has been used to separate each particle size of the dry soil by assembling in order of 4, 10, 20, 40, 80, 100, and 200 mesh sizes. The soil from Gamcheon Port in Busan drops upper side of the sieve and shakes back and forth to separate each different size of the particle. The 1L of Imhoff cone and 200 mL of the mass cylinder were used as settling tanks to calculate settling velocity. Stokes' equation was used to figure out the average density of dry soil with a value from settling velocity. In the results, the average particle density and lowest settling velocity were 1.93 g/cm³ and 0.11 cm/s, respectively. These values can detect the range of settling points of sediment to prevent chemical accidents. In pH neutralization, the initial pH of 2, 3, 4, and 5 of nitric acid and sulfuric acid are used as an acid solution; 0.1, 0.01, and 0.001 M of sodium hydroxide and calcium hydroxide are used as a base solution. The main goal of this experiment is to figure out the volume percentage of the acid solution becomes pH 7. The concentration of 0.001 M of base solution exceeds all the conditions, 0.01 M exceeds partially, and 0.1 M does not exceed 5 v/v% except pH 2. Calcium hydroxide present less volume than sodium hydroxide at pH neutralization both sulfuric and nitric acid.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.101-107
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• 2016

This paper investigates the feasibility of applying the jet loop reactor for the neutralization of alkaline wastewater using carbon dioxide ($CO_2$). In this study, pH changes and $CO_2$ removal characteristics were examined by changing influent flow rate of alkaline wastewater (initial pH=10.1) and influent $CO_2$ flow rates. Influent flow rates of alkaline wastewater ($Q_{L,in}$) ranged between 0.9 and 6.6 L/min, and inlet gas flow rate ($Q_{G,in}$) of 1 and 6 L/min in a lab-scale continuous flow jet loop reactor. The outlet pH of wastewater was maintained at 7.2 when the ratio ($Q_{L,in}/Q_{G,in}$) of $Q_{L,in}$ and $Q_{G,in}$ was 1.1. However, the $CO_2$ removal efficiency and the outlet pH of wastewater were increased when $Q_{L,in}/Q_{G,in}$ ratio was higher than 1.1. Throughout the experiments, the maximum $CO_2$ removal efficiency and the outlet pH of wastewater were 98.06% and 8.43 at the condition when $Q_{G,in}$ and $Q_{L,in}$ were 2 L/min and 4 L/min, respectively.