• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.342-342
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• 1998

The effect of pH on the dehydration reaction of TiCl₄solution. KOH and HCl were used as a accelerater and retarder in dehydration. Results are follow. Neutralization point is pH 7.4 in the system of $TiCl_4-KOH$ and the production which is produced at acidic side is Ti-gel of poly metatitanic acid. The production which is produced at alkalic side is aligomer and crystalline potasium titanate is not detected.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.415-418
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• 2005

Nowadays the three major commercially available of organic chemical admixtures are modified lignosulfonates(LS), sulfonated naphthalene-formaldehyde resins (SNF) and sulfonated melamine-formaldehye (SMF). In this study, various sulfonated melamine-formaldehyde (SMF) superplasticizers were synthesized via four synthetic steps. Hydroxymethylation (Step 1), Sulfonation (Step 2), Polymerization (Step 3) and Neutralization and Stabilization (Step 4). In this synthesis of SMF, reaction conditions such as the mole ratio of melamine to formaldehyde and the amount of acid catalyst were changed. After application of SMF superplasticizer to cement paste and mortar, the physical properties including workability, slump loss, compressive strength were compared.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.733-742
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• 2000

Fundamental materialistic characterization and adsorption/neutralization behavior of waste egg shell for heavy metal ion have been studied for its application to wastewater treatment. To investigate the structural change and thermal decomposition characteristics of egg shell. X-ray diffraction and FT-IR analysis were conducted for egg shell treated at $105^{\circ}C$ and $700^{\circ}C$, respectively. For the result of FT-IR analysis, the sample treated at $700^{\circ}C$ showed a reduced C-O absorption band compared with that of egg shell treated at $105^{\circ}C$, which may be due to the $CO_2$ release. Unlike to the result of FT-IR analysis, the XRD patterns of egg shell were almost similar for the cases of $105^{\circ}C$ and $700^{\circ}C$ treatment. however, characteristic diffraction pattern of CaO was observed for $850^{\circ}C$ treatment, at which $CaCO_3$ is known to be completely converted to CaO. TGA/DTA analysis showed a slow decline in weight loss up to $600^{\circ}C$ and, for $600{\sim}800^{\circ}C$ range, the weight loss became drastic by reason of $CO_2$ discharge, which was accompanied by an appearance of major endothermic peak. The ratio of practical breakthrough time to ideal one, total transfer unit, and mass transfer coefficient were observed to be increased as the adsorption was progressed in a multiple-column fixed-bed reactor using egg shell as an adsorbent, which signified the distribution effect of mass transfer for continuous adsorption reaction. The neutralization effect of egg shell for several types of acidic wastewater made of different mineral acids was not much different from each other except for the case of $H_2SO_4$, for which the neutralization reaction was thought to be retarded by the formation of gypsum.

• IMMUNE NETWORK
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• v.2 no.3
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• pp.142-149
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• 2002

Background: Our previous study showed that purified protein derivative (PPD)-stimulated pleural mononuclear cells (PMC) from tuberculous pleurisy (Tbp) produced significantly more $IFN-{\gamma}$ (10- to 70-fold) after in vitro PPD stimulation than freshly isolated pleural cells from malignant pleurisy. The present study was designed to determine whether blocking the CD40-CD40 ligand (CD40L) interaction decreases $IFN-{\gamma}$ production by altering IL-12 levels. Methods: IL-12 and $IFN-{\gamma}$ production after neutralizing anti-CD40L antibody treatment was compared to the efficacy of anti-CD80, anti-CD86, and a combination of anti-CD80 and CD86 (CD80+86) monoclonal antibodies (mAb). These activities were measured by enzyme-linked immunosorbent assays (ELISAs) and reverse transcription-polymerase chain reaction (RT-PCR), after in vitro stimulation with PPO antigen (Ag). Results: Neutralization of CD80, CD86 and CD80+86 did not decrease $IFN-{\gamma}$ and IL-12 production in Tbp-PMC, whereas neutralization of CD40L significantly depressed IL-12 p40 and $IFN-{\gamma}$. In addition, neutralization of CD40L completely inhibited IL-12 p40 and $IFN-{\gamma}$ mRNA expression. Conclusion: The CD40-CD40L interaction might play a major role in IL-12 and $IFN-{\gamma}$ production in Tbp-PMC, thus contributing to protective immunity in human tuberculosis.

• Biomedical Science Letters
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• v.6 no.2
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• pp.141-149
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• 2000

The etiologic agents of haemorrhagic fever with renal syndrome (HFRS) in Korea are Hantaan and Seoul virus in the genus Hantavirus, family Bunyaviridae. Antibody titers of sera from HFRS patients against Hantaan virus were measured by immunofluorescent antibody technique (IFAT), enzyme-linked immunosorbent assay (ELISA), high density composite particle agglutination (HDPA) and plaque reduction neutralization test (PRNI). PRNT and nested reverse transcriptase polymerase chain reaction (nested RT-PCR) was used for serotypic differentiation of Hantaviruses against Hantaan and Seoul virus. Eight doubtful HFRS patients showed higher fluorescent, IgG ELISA, agglutination and neutralizing antibody titer by IFAT, ELISA IgG, HDPA and PRNT, respectively Five out of them showed high IgM antibody titer by IgM capture ELISA against Hantaan virus, remarkably. Fifteen HFRS patients showed higher fluorescent antibody titer by IFAT. In PRNT, 12 out of them showed high neutralizing antibody titer against HTNV, 2 against SEOV and 1 against both viruses. In nested RT-PCR using serotype specific-primer, 3 out of them showed positive against HTNV and 1 against SEOV.

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.575-580
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• 2020

In this study, we simulated an amine regeneration process with heat-stable salts removal unit. We derived the optimal operating conditions considering the flow rate of waste, the removal rate of heat-stable salts, and the loss rate of MDEA (methyl diethanolamine). In the amine regeneration process that absorbs and removes acid gas, heat-stable salt impairs the absorption efficiency of process equipment and amine solution. An ion exchange resin method is to remove heat-stable salts through neutralization by using a strong base solution such as NaOH. The acid gas removal process was established using the Radfrac model, and the equilibrium constant of the reaction was calculated using Gibbs free energy. The removed amine solution is separated and flows to the heat-stable salts remover which is modeled by using the Rstoic model with neutralization reaction. Actual operation data and simulation results were compared and verified, and also a case study was conducted by adjusting the inflow mass of removal unit followed by suggesting optimal conditions.

• Journal of the Korean institute of surface engineering
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• v.49 no.6
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• pp.513-520
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• 2016

Many surface protection methods have been developed to apply to constructional steels which have been used under severe corrosive environments. One of these methods, hot dip galvanizing is being widely used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for manufacturing ship and for some other industrial fields etc.. Recently, the cost of zinc is getting higher and higher, thus, it is considered that improvement of hot dip galvanizing process to reduce the cost of production should be developed possibly. In this study, additives such as acid cleaning solution, $NH_4OH$, $Al(OH)_3$ and $H_2O_2$ were added to flux solution, and omission of water washing treatment after acid cleaning was investigated with some types of flux solutions added with some additives mentioned above. The decrement of pH by adding the acid cleaning solution could be controlled due to neutralization reaction with addition of $NH_4OH$. The flux solution added with both $NH_4OH$ and $Al(OH)_3$ exhibited nearly the same color and pH value as those of orignal flux solution with no added, and the sample dipped to the flux solution which was added with additives mentioned above indicated a relatively good corrosion resistance compared to other samples. However, the flux solution added with $NH_4OH$, $Al(OH)_3$ and $H_2O_2$ exhibited a different color, sediment and a bad corrosion resistance. Consequently, it is considered that omission of water washing treatment may be able to perform by adding optimum additives to the original flux solution.

• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.83-92
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• 2005

Dissolution rate of minerals may differ from climates configuration, but weathering rate of feldspars is generally proved to be relatively higher The result of geochemical reaction modeling indicates the acid water of pH 4.5 excluding any other variables, was 2.3 times higher than that in ordinary rain of pH 5.7. This result proved that pH is very important factor in preservation of granite cultural properties. To prevent the weathering of stone cultural properties, weathering characteristics of stones should be studied first and constitution of dry environments, using water repellent or oil coating, isolating water which cause chemical weathering reaction like hydration and oxidization should be considered. Considering the long-term reactions between granite and rain, selection of materials, which can bring neutralization and non-oxidization conditions, are very important in using cleaning agents and biological controls.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.62-66
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• 2018

Styrenated phenol alkoxylates (SP-A) were prepared from styrenated phenol (SP) and ethylene oxide (EO) under a homogeneous base catalyst. However, to use EO that is difficult to handle, a high-pressure reaction device capable of controlling the reaction process should be used. Additionally, when a homogeneous base catalyst is used, a neutralization process is required to remove residual bases after the reaction, and it is also difficult to separate the catalyst and the product. Therefore, in this study, we report the results of SP-A prepared from the reaction of SP and EC using only heterogeneous base catalysts. The heterogeneous base catalyst was obtained by supporting KOH on $La_2O_3$ and calcintion. Using EC instead of EO, it was possible to produce SP-A under the atmospheric rather than high-pressure reaction condition. Average molecular weights of synthesized SP-A varied greatly depending on reaction conditions. The average molecular weight of SP-A prepared using the $KOH/La_2O_3$ catalyst could be controlled arbitrarily by controlling the reaction temperature and added catalyst and EC amounts.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.521-529
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• 2011

Methanol-to-olefin (MTO) reaction was studied over MWW zeolite with independently developed two pores (circular and straight) and MFI zeolite with intercrossed sinusoidal and straight pores in order to investigate the effect of pore structure on their catalytic behavior. MWW and MFI zeolites with similar acidity exhibited commonly high conversion and slow deactivation in the MTO reaction, but their product selectivities were considerably different: linear hydrocarbons of $C_3-C_9$ were mainly produced on MWW, while the yield of $C_2{^=}$ and aromatics were high on MFI. Polyaroamatic hydrocarbons (PAHs) were accumulated on MWW, but a small amount of benzene and aromatics on MFI. The impregnation of phosphorous on MWW caused significant decreases in the catalytic activity and toluene adsorption, but the decreases were relatively small on MFI. Although the straight pores of MWW were inactive in the MTO reaction due to the accumulation of PAHs, its circular pores which suppressed the formation of PAHs sustained catalytic activity for the production of linear hydrocarbons. Therefore, the impregnation of phosphorous on the circular pores of MWW caused a significant decrease in catalytic activity. The phosphorous impregnation on the cross sections of MFI altered the product selectivity due to the neutralization of strong acid sites, but catalytic deactivation was negligible. The difference of MWW and MFI zeolites in the MTO reaction was explained by their difference in pore structure.