• Journal of the Korean institute of surface engineering
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• v.43 no.6
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• pp.297-303
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• 2010

The effect of solution acidity and organic additives, polyethylene glycol (PEG), on the trivalent chromium electroplating was systematically investigated in the view point of electroreduction of trivalent chromium ions and solution stability. It was found that solution acidity controlled at pH 2.5 showed the widest current range for bright electrodeposits in the presence of PEG additives, which reduced the local current intensification at high current densities. Through complex interaction between PEG additives and hydrogen ion, that is, solution acidity, electrode potential was moved in the negative direction in the bulk solution, while it shifted in the positive when electric potential was scanned. In conjunction with electrochemical quartz crystal microbalance (EQCM), it was found that PEG additives had a role in promoting the electron transfer to trivalent chromium ion complexes in bulk solution and their adsorption at the electrode surface as well as interfering with hydrogen ion reduction process below pH 2.5. The PEG additives developed the nodular morphology during electroreduction of trivalent chromium ions with the increase of solution acidity and enhanced its current efficiency by maintaining the consumption of complexant, formic acid, at low speed.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.47-48
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• 2011

The effect of solution acidity and organic additives, polyethylene glycol (PEG), on the trivalent chromium electroplating was systematically investigated in the view point of solution stability, electroreduction of trivalent chromium ions and characterization of deposition layer. It was found that, the concentration of fraction chromium complexes in the trivalent chromium bath containing formic acid is strongly depended on pH value. PEG molecules were stable in trivalent chromium bath containing formic acid via studies on electrospray ionization mass spectrometry (ESI-MS) and UV-Vis. However, the presence of PEG molecules decreased the reductive current of hydrogen evolution, increasing of current efficiency higher about 10 % compared with solutions without PEG. Moreover, PEG additives developed the nodular morphology during electroreduction of trivalent chromium ions with the increase of solution acidity and enhanced its current efficiency by maintaining the consumption of complexant, formic acid, at a low speed. In this study, the effect of solution acidity was emphasized important, there, it controlled the formation of complexes in the solution, cathodic film (CF) during deposition, and properties of deposited layer. By electrochemical quartz crystal microbalance (EQCM), studies show that chromium electrodeposition occurs via the formation of intermediate complexes and adsorption on the cathode surface, which hinder the penetration of ions from bulk solution to the cathode surface.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.606-612
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• 1995

Three different Oyijangachi(Kochujang, Doenjang and Ganjang) have been prepared by traditional method. Cucumbers have been dipped in six different solutions for 48 hrs. After dipping, the cucumbers have been aged in Kochujang, Doenjang and Ganjang for 30 days. The acidity, pH, salt content and sensory evaluation of the cucumbers which were treated by six different solutions has measured. Moisture content of fresh cucumber was 95%, and the moisture content of Kochujang, Doenjang and Ganjang of Oyijangachi was 66.78%, 76.94% and 81.33%, respectively, after 30 days of aging. Protein content fo Kochujang, Doenjang and Ganjang of Oyijangachi increased 57%, 258% and 197%, respectively, after 30 days of aging when they compared with fresh cucumber(control). Initial acidity of Oyijangachi of cucumbers which were treated with solution 1~5 at 0 day were between 0.49 and 0.56 and increased during aging. Initial acidity of Oyijangachi treated with solution 6 was 1.84 which was low because 1% of acetic acid was added and acidity increased during aging. The pH of Kochujang, Doenjang, and Ganjang of Oyijangachi decreased 4.37, 3.98 and 4.61, respectively, after 30 days aging. Salt content of Oyijangachi dipped in various salt solutions increased as the salt content of the solution increased. Salt content of three Oyijangachi increased drastically during 0~5 days of aging and slowly increase between 5~30 days of aging. The taste and smell of Kochujang Oyijangachi were highest as treated wih 12% NaCl solution(treatment 4) and the color was highest when the Oyijangachi was treated with solution 1. The taste, smell and color of Doenjang Oyijangachi were highest as treated with 12% NaCl solution plus CaCl2(treatment 5). It was observed that the firmness of Oyijangachi was generally higher as the cucumber treated.

• Journal of the Korean Home Economics Association
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• v.38 no.2
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• pp.21-26
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• 2000

Effect of aluminum dissolution from aluminum sauce pans with the kind and concentration of acidity, boiling times and temperature of acidity solution, in new and old sauce pans, and aluminum content in typical food was investigated. As acetic acid concentration increases, aluminum content has increased. But malic acid and citric acid have suddenly increased until acidity concentration would be 0.4%. After that rapidly increasing is not shown. As boiling time and temperature of acidity solution increases, concentration of aluminum dissolved from aluminum sauce pan has increased. Concentration of aluminum by repeated use has increased only a slightly. But aluminum content has dissolved in large quantities from new pan rather than old pan.

• The Korean Journal of Food And Nutrition
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• v.14 no.4
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• pp.333-338
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• 2001

In research. which Korean pickled cucumber was treated wish various methods, including blanching. brining in hot solution, and treating with trehalose. I examined the changes of properties of material. The Korean pickled cucumber were fermented 4∼5$^{\circ}C$ for 42 days in 1% salt solution. The physiochemical properties were pH, total acidity, total cell count, lactic acid bacteria and texture properties were also evaluated. The result showed that the effect of blanching and soaking cucumber in 100$^{\circ}C$ hot salt solution significantly reduced the softening rate of texture while a rather rapid fermentation was found for those preserved with salt. The effect of trehalose treatment inhenced fermentation but it was significantly reduced softening rate of texture. The texture evaluation of Korean pickled cucumber was found that heat treatment with blanching after soaked in hot solution and trehalose treatment had a positive effect for reduction of softening of cucumber tissue.

• Journal of the Korean Chemical Society
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• v.9 no.4
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• pp.179-184
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• 1965

Korean acid clays and Japanese acid clay were 1 N KCl solution and then their acidities were determined by measuring pH of the filtrates produced. And on examining the effect of neutral salt solution, such as KCl, NaCl, $BaCl_2,\;Pb(NO_3)_2\;and\;CuSO_4$, on the acidity, it was found that the effect decreased in order mentioned above and this situation proved to be in accord with Lyotrope series, i.e., the order of $K^+>Na^+>Ba^{++}>Pb^{++}>Cu^{++}.$ And after adsorbing cation, $Al_2O_3\;and\;Fe_2O_3$ which dissolved out of acid clay were measured, with the result that the amounts dissolved out were nearly proportional to acidity. This result accords with Kobayashi and Yamamoto's theory that the cause for acidity of clays is due to the fact that HCl which is formed initially by exchange of cation reacts with solid clay, and then chlorides dissolved out bring about hydrolysis, then resulting in the second formation of HCl. On measuring the rate which acid clay adsorbed dye in aqueous solution of basic and acid dyes, it was found that acid dye had no relation to acidity, and though it was not adsorbed by acid clay, the adsorption rate of basic dye was proportional to acidity. After adsorbing basic dye, pH was proportional to both acidity of solid acid and its adsorption rate of dye. Hence, it was concluded that the adsorption of basic dye was in accord with adsorption mechanism of neutral salt. This study led to find the acidic cause of solid acid and its adsorption mechanism of dye in aqueous solution.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.33.1-33.1
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• 2018

pH is expressed mathematically as $pH=-{\log}[H^+]$, is a measure of the hydrogen ion concentration, [$H^+$] to specify the acidity or basicity of an aqueous solution. The pH scale usually ranges from 0 to 14. Every aqueous solution can be measured to determine its pH value. The pH values below 7.0 express the acidity, above 7.0 are alkalinity and pH 7.0 is a neutral solution. The solution pH can be determined by indicator or by measurement using pH sensor, which measuring the voltage generated between a glass electrode and a reference electrode according to the Nernst Equation. The pH value of solutions depends on the temperature and the activity of contained ions. In nickel electroless plating process, the controlled pH value in some limited ranges are extremely important to achieve optimal deposition rate, phosphorus content as well as solution stability. Basically, nickel electroless plating solution contains of $Ni^{2+}ions$, reducing agent, buffer and complexing agents. The plating processes are normally carried out at $82-92^{\circ}C$. However, the change of its pH values with temperatures does not follow any rule. Thus, the purpose of study is to understand the relationship between pH and temperature of some based solutions and electroless nickel plating solutions. The change of pH with changing temperatures is explained by view of the thermal dynamic and the practical measurements.

• Journal of Nutrition and Health
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• v.15 no.1
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• pp.22-29
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• 1982

As sugar and amino acid were added to the ascorbic acid solution the content of ascorbic acid was quantitatively determined by 2, 4-dinitrophenyl hydrazine method. The residual ascorbic acid was shown to increase slightly when sorbose, rhamnose or mannose was added to the ascorbic acid solution whereas residual ascorbic acid was shown to decrease in time to the addition of other sugars. The effects of amino acid to the ascorbic acid solution were found that monoamino-mono, or dicarboxylic acids and aromatic amino acids increased the residual ascorbic acidity whereas diamino-monocarboxylic acids and sulfur containing amino acids decreased the residual ascorbic acidity.

• Textile Coloration and Finishing
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• v.11 no.4
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• pp.39-49
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• 1999

In order to study the properties of cochineal colors, uv-visible spectra of cochineal colors solution, dyeing properties on the wool in several dyeing conditions and thermodynamic parameters were investigated. UV-visible spectra of cochineal colors solution showed hypochromic effect with the lapse of irradiation time but bathochromic shift with decreasing acidity of solution and addition of metallic ions. The concentration of cochineal colors in wool fiber increased with the increase of dyeing temperature, time, and acidity of initial dyebath. The value of apparent diffusion coefficients and standard affinities of dyeing decreased with the increase of dyeing temperature. The standard heats of dyeing$(\Delta{H}^\circ)$ and variation of entropy$(\Delta{S}^\circ)$ increased with the increase of concentration of initial dyebath. The activation energy$(E_a)$ were calculated to be 1.399~2.595kcal/mol in condition of 6~1%(o.w.f) dyebath. Wool fabrics were dyed reddish blue by iron sulfate, copper sulfate, aluminum acetate and tannic acid, and red by tin chloride, respectively. Lightfastness of wool fabrics dyed by cochineal colors were increased by mordant treatment, especially copper sulfate and iron sulfate treatment.

• Journal of Environmental Health Sciences
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• v.1 no.1
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• pp.32-35
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• 1974

Acidic substances contained in asphalt are affect upon emulsitiability of asphalt and its adhesion with aggregates, and therfore, detemination of acidity of asphalt is of important one. However, there has not been established a method of precisely determining the acidity of asphalt. This paper reports on an improved color-indicator titration method, by which the acid number of asphalt is determined. By treating benzene solution of asphalt with alcohol, acidic constituents were selectively extracted into alcohol solution, while asphaltic matters precipitated. A color-indicator titration method then was applied to the resultant faint-colored solution. The change of color at end point was clearly observed, and the results were obtained with good reproductivity and checked well with the results by the I.P. 177/64 method. Alcohols having not more than three cabon atoms have been found suitable for extraction.