• Journal of Korean Society for Atmospheric Environment
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• v.32 no.5
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• pp.485-500
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• 2016

We examined acidity state of inorganic aerosol and oxidation state of organic aerosol by High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) at Baengnyeong Super site from Jan 2012 to Dec 2013. Additionally, we carried out the analysis for the aerosol component group of organic matter ($C_xH_y$, $C_xH_yO_1$, $C_xH_yO_z$, $C_xH_yO_zN_p$) and elemental composition to calculate H/C, O/C, N/C, OM/OC and identify the oxidation state. The aerosol chemical composition in this study is dominated by sulfate ($SO_4{^{2-}}$), nitrate ($NO_3{^-}$) plays a smaller role in aerosol acidity. Ammonium ($NH_4{^+}$) was found in a formation of $(NH_4)_3H(SO_4)_2$. However, the binding formations of $NH_4NO_3$ and $NH_4Cl$ increase in the winter. $C_xH_yO_1$ indicating the oxidized state of $PM_{1.0}$ has the highest ratio of 41% while $C_xH_y$ indicating the non-oxidized state has a lower ratio of 36%, meaning that the oxidation level of $PM_{1.0}$ in Baengnyeong Island is high. The ratio between H/C and O/C was 1.33 and 0.78 respectively, showing the characteristic of LV-OOA (Low volatility-Oxygenated Organic Aerosol). Acidic and oxidized aerosols sampled during this field study were largely anthropogenic in origin from Chinese continent and photochemically aged.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.1
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• pp.35-42
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• 2018

Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the $C_{max}$ value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their $T_{max}$ values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.615-623
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• 2000

The brine Korea cabbage (BKC) with various ingredients was stored at 5$^{\circ}C$ and 15$^{\circ}C$ for 13 days to examine the changes in pH, total acidity, ascorbic, and cholrophylls. Decrease in pH and increase in total acidity in the BKC stored at 15$^{\circ}C$ were greater than in the BKC stored at 5$^{\circ}C$, indicating these changes are closely related to the storage temperature. The effect of ingredints was various; garlic, red pepper powder, and fermented anchovy juice accelerated the decrease in pH and increase in total acidity; mustard powder and leaf mustard suppressed their changes and freen onion and ginger had no effect. At both temperatures, ascorbic acid was remained at high level in the BKC with leaf mustard, but it was maintained at lowest level in the BKC with ferented anchovy juice. Degradation od chlorophylls was slow in the BKC with leaf mustard, which maintained the high level os ascorbic acid during storage. Meanwhilr the degradation of chlorophylls or production of pheophytin and pheophorbide was cinsistent with the production of acid. These results suggset that degradation of chlorophylls in a BKC was positively correlated with ascorbic acid content and the acid produced during storage.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.151-155
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• 2007

The issue of acid precipitation and related environmental problems in East Asia have been emerging. To evaluate the acidity and chemical characteristics of rainwater in Korea, its chemical properties during crop cultivation season from April to October were investigated at Suwon, Korea. Also, to estimate the contribution of ions on its acidity, ion composition characteristics and neutralization effects by cation ions were determined. Ion balance and electrical conductivity balance between the measured and estimated values showed high correlation. Rainwater had distributed highly in the range of pH 4.5~5.6. The pH of rainwater was relatively high at June as compared with other monitoring periods. $Na^+$ was the main cation followed by $NH_4{^+}$, $Ca^{2+}$, $H^+$ > $K^+$ > $Mg^{2+}$. Among these, $Na^+$, $NH_4{^+}$, $Ca^{2+}$ and $H^+$ covered over 93% of total cations. About 86% of anion in rainwater was composed of $SO{_4}^{2-}$ and $NO_3{^-}$. In rainwater samples, $NH_4{^+}$ and $Ca^{2+}$ contributed greatly to neutralization of the rain acidity. Also, 88% of soluble sulfate in rainwater was nss-$SO{_4}^{2-}$(non-sea salt sulfate).

• The Korean Journal of Food And Nutrition
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• v.14 no.6
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• pp.512-520
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• 2001

Kimchi is one of the traditional Korean food and a very popular side dish in Korea. To obtain funda mental data on how to prevent over ripening in kimchi after acidity of 0.4% was reached during the lactate fermentation, the physicochemical characteristics such as pH. acidity. organic acids, enzyme activity were measured and the time dependent ecology of microorganism were observed. In the initial stages of fermentation, the pH of kimchi was markedly changed and slowly decreased in 0.5% acidity The acidity was slowly increased and markedly increased in pH 4 by growth of microorganism. HPLC analysis showed oxalic acid, lactic acid, acetic acid, malic acid and succinic acid and this results reconfirmed by GC-MSD. Lactic acid was changed a lot during fermentation period as the time of storage went on, where as malic was decreased. Kimchi A, having acidity of 0.75%, showed the highest acidic Protease and lipase activity. Also, the amylase activity was high in kimchi C, having 0.95% acidity. The total viable bacteria showed 8.1$\times$10$^{5}$ , 4.7$\times$10$^4$, 1.2$\times$10$^3$, 3.2$\times$10$^4$, 4.9$\times$10$^{5}$ cfu/ml in the kimchi A, B, C, D and E, respectively. The numbers of lactic acid bacteria counted 1.0$\times$10$^{5}$ , 1.3$\times$10s, 1.2$\times$10$^3$, 2.3$\times$ 10$^3$, 2.1$\times$10$^4$c1u/m1 in the kimchi A, B, C, D and E, respectively. The numbers of acetobactor were counted 1.8$\times$10$^{5}$ , 9.3$\times$10$^4$, 7.0$\times$10$^1$, 4.5$\times$10$^4$, 5.3$\times$10$^3$cfu/m1 in the kimchi A, B, C, D and E, respectively.

• Journal of Sericultural and Entomological Science
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• v.39 no.2
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• pp.106-113
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• 1997

Three indigenous mulberry species of Morus tiliaefolia Makino, Morus mongolica C. K. Shneider and Morus bombycis Koidz. were naturally crossed and their fertilities and fruit characteristics were investigated during the years of 1996 and 1997. M. tiliaefolia Makino and M. mongolica C.K. Schneider showed low fertility, but M. bombycis Koidz. was medium in fertility. The fruits of M. tiliaefolia Makino were red-purple and midium in size and high sugar content, but those of M. mongolica C.K. Schneider were light red and small but extremely high sugar content. The total acidity of fruits was 0.73, 0.50 and 0.36-0.94% in M. tiliaefolia Makino, M. mongolica C.K. Schneider and M. bombycis Koidz. respectively. Regarding ripenening stage, M. mongolica C.K. Schneider was early and M. tiliaefolia Makino was medium, while M. bombycis Koidz was early or medium.

• Journal of Applied Biological Chemistry
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• v.56 no.2
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• pp.101-107
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• 2013

Physicochemical properties of kochujang prepared with different concentration of turmeric were compared. The number of yeast and bacteria in the kochujang were low in the group with more than 1% of turmeric while the amylase and protease activity increased in the group with less than 1% of turmeric. The L- and b-values increased as the concentration of turmeric increased, however a-value decreased. The titratable acidity was low in the high percentage of turmeric added group. Oxidation-reduction potential increased in the later stage of fermentation with decrease in Aw. Reducing sugar and alcohol were high in than higher turmeric added group. Amino- and ammonia-type nitrogen were the highest in the 0.5% turmeric added group. The overall acceptability of kochujang was significantly more favorable (p<0.05) in the 0.25% turmeric added group than over 1% turmeric added one.

• Journal of the Semiconductor & Display Technology
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• v.2 no.3
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• pp.1-6
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• 2003

In the rapid changes of the semiconductor manufacturing technologies for early 21st century, it may be safely said that a kernel of terms is the size increase of Si wafer and the size decrease of semiconductor devices. As the size of Si wafers increases and semiconductor device is miniaturized, the units of cleaning processes increase. A present cleaning technology is based upon RCA cleaning which consumes vast chemicals and ultra pure water (UPW) and is the high temperature process. Therefore, this technology gives rise to environmental issue. To resolve this matter, candidates of advanced cleaning processes have been studied. One of them is to apply the electrolyzed water. In this work, electrolyzed water cleaning was compared with various chemical cleaning, using Si wafer surfaces by changing cleaning temperature and cleaning time, and especially, concentrating upon the contact angle. It was observed that contact angle on surface treated with Electrolyzed water cleaning was $4.4^{\circ}$ without RCA cleaning. Amine series additive of high pKa (negative logarithm of the acidity constant) was used to observe the property changes of cathode water.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.352-355
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• 2003

27 passive systems in 21 mines constructed by The Coal Industry Promotion Board since 1996 were investigated to evaluate the treatment efficiency of systems and find problems in each system, which will eventually lead to the improvement or suggesting the alternative method of the passive treatment system. Problems in operation include overflow, leakage, inefficiency and unusablness. The efficiency of systems which has been evaluated by metal(Fe) removal rate and/or by acidity removal rate do not reflect the poor removal rate of S $O_4$$^{2-}$. Especially high concentration of S $O_4$$^{2-}$ and high COD in the beginning of the operation would decrease the bacteria activity due to the lack of the nutrition. To solve the problem of overflow the upflow-type SAPS is being considered.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.377-380
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• 1992

To produce economically important acid with pear juice, an acetic acid bacterium was selected from many isolated acetic acid bacteria. The alcohoic fermentation was conducted by inoculating pear juice with Saccharomyces cerevisiae ATCC 4124, and then the pear vinegar was prepared by batch cultivation in flaskes with the isolated Acetobacter sp. The optimum conditions for high yield of acetic acid were studied experimentally in the batch shake flask . For seed purposes the Acetobactor sp. was cultivated for 2 -days and transferred to the acid production medium . Optimum alcohol concentration, initial acidity and temperature for the acid production were 8.0% , 2.0% and 28$^{\circ}C$, respectively. Under the same conditions, the addition of yeast extract (1%) was observed to produce relatively high yield of acetic acid.