• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.190-194
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• 2009

In this study sodium dodecyl sulfate (SDS), which was anionic surfactant, was added for forming micelles to remove iron ion that could be contained with small amount in industrial water. Then aggregates binding between iron ions and micelles were rejected by a ceramic microfiltration membrane. As result of SDS concentration effect on removal rates of iron and SDS in modified iron solution, the removal rate of iron was the highest value of 92.26% and the removal rate of SDS was 61.10% a little higher than the result of calcium ion at 8 mM which was CMC (Critical micelle concentration) of SDS. As final resistance of membrane fouling $R_f$ increased the more at the higher SDS concentration, it showed the highest value at 4 mM and the lowest at 10 mM of SDS. The final permeate flux $J_{180}$ had the highest value and the largest total permeate volume could be finally acquired at SDS 10 mM. In case of CMC 8 mM, low $R_f$ was shown as same as that of 10 mM until 80 minutes of operation, and tended to increase dramatically to 120 minutes and increase slowly again until 180 minutes.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.286-294
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• 1987

This experiment was carried out to investigate the bacteriolytic action of the egg white lysozyme isolated from Korean native Ogol fowl and to obtain the data for utilization of the enzyme as a food preservative. Staphyococcus aureus phage type 29 and Bacillus subtilis ATCC 6633 among the microorganisms tested were lyzed by the treatment with 0.05% lysozyme, but Staphylococcus aureus phage type 57 in addition to E. coli etc. was found to be a lysozyme- insensitive species. The lysis of S. aureus phage type 29 was maximized when incubated in nutrient broth (pH 7.0) at $37^{\circ}C$ for 24 hours and suspended it to absorbance 0.6 at 540nm in 0.05M sodium acetate but fer (pH 4.5) and then treated it with the 0.05% lysozyme for 30 min. at $30^{\circ}C$. It was found that the effect of 0.05% lysozyme in combination with 1% glycine on the growth inhibition of S. aurecus phage type 29 increased more 50% than that in the absence of glycine, but not effect with other any additeves and metal ions tested.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.121-121
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• 2004

The groundwater in the Pocheon area occurs from both a fractured bedrock aquifer in igneous and metamorphic rocks and an alluvial aquifer with a thickness of <50 m, and forms a major source of domestic and agricultural water supply. In this study, we performed a hydrogeochemical study in order to identify the control of geochemical processes on groundwater quality. For this study, groundwater level and physicochemical parameters (EC, Eh, pH, alkalinity) were monitored once a month from a total of 150 groundwater wells between June 2003 to August 2004. A total of 153 water samples (13 surface water, 66 alluvial groundwater, 74 bedrock groundwater) were also collected and analyzed in February 2004. Groundwater chemistry in the study area is very complex, depending on a number of major factors such as geology, degree of chemical weathering, and quality of recharge water. Hydrochemical reactions such as the leaching of surficial and near-solace soil salts, dissolution of calcite, cation exchange, and weathering of silicate minerals are proposed to explain the chemistry of natural groundwater. Alluvial groundwaters locally have very high TDS concentrations, which are characterized by their chloride(nitrate)-sulfate-bicabonate facies and low Na/Cl ratio. Their grondwater levels are highly fluctuated according to rainfall event. We suggest that high nitrate content and salinity in such alluvial groundwaters originates from the local recharge of sewage effluents and/or fertilizers. Likewise, high concentrations of nitrate were also locally observed in some bedrock groundwaters, suggesting their effect of anthropogenic contamination. This is possibly due to the bypass flow taking place through macropores. Tile degree of the weathering of silicate minerals seems to be a major control of the distribution of major cations (sodium, calcium, magnesium, potassium) in bedrock groundwaters, which show a general increase with increasing depth of wells. Thermodynamic interpretation of groundwater chemistry shows that the groundwater in the study area is in chemical equilibrium with kaolinite and Na-montmorillonite, which indicates that weathering of plagioclase to those minerals is a major control of hydrochemistry of bedrock groundwater. The interpretation of the molar ratios among major ions, as well as the mass balance calculation, also indicates the role of both dissolution/precipitation of calcite and Ca-Na cationic exchange as bedrock groundwaters evolves progressively.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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• pp.37-49
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• 2015

During pregnancy, the maternal body undergoes significant physiological changes. The present study assessed the changes on calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na) and potassium (K) metabolism in singleton and twin-pregnant dairy goats. The 42 goats used ($49.5kg{\pm}7.6$ body weight [BW]) were assigned at random to treatments that were factorially arranged to account for 2 breeds (Oberhasli and Saanen), 2 pregnancy types (singleton and twin) and 3 gestation periods (80, 110, and 140 days). Digestibility trials were performed at 80, 110, and 140 days of gestation. Mineral retention during pregnancy was determined in the maternal body, femur, uterus, mammary gland, fetus and fetal fluid. Blood samples were taken during pregnancy before and after a meal, and Ca, P, Mg, Na, K ions and alkaline phosphatase activity determined in serum. Bone mineral density was determined in the right femur. Statistical analyses were performed using the SAS MIXED procedure. Dry matter intake decreased linearly up to 140 days of gestation. Maternal BW gain, and Ca, P, and Mg retention (g/kg) decreased linearly with the advance of gestation days. Macromineral retention in maternal body (g/kg) was greater in Oberhasli than Saanen goats, and their fetuses had higher Ca, P, and Mg deposition (mg/g). Mineral retention (mg/g) increased in fetuses according to pregnancy development, with no differences between singleton and twin pregnancy. In the mammary gland, the retention of all minerals (g) increased with the days of pregnancy. In conclusion, related to Ca, P, and Mg metabolism can be divided into two stages. Up to 80 days of gestation, was characterized by the preparation of the maternal body reserves for future mineral demands. From 80 days of gestation onward, was characterized by the transfer of maternal body reserves for fetal development and colostrum production. Na and K supply was provided by adjustments in endogenous excretion and an increase in intestinal absorption. Finally, mineral metabolism was specific to each genotype and, except for Na, was not affected by the number of fetuses.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.261-272
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• 2005

The groundwaters in the basin of Seomjin River are classified mainly into Na-Cl type with high EC and $NaHCO_3$ type with low EC, and are characterized by enriched $K^+,\;Mg^{2+},\; NO_3^-,\; and\;SO_4\;^{2-}$ contents. The epm fraction of $Na^+Cl^-$ in TDS increases in general with increasing EC of groundwater. The correlation patterns among dissolved ions indicate that $Na^+\;and\;Cl^-$ are derived mainly from intruded seawater, and $K^+,\;Mg^{2-},\;and\;SO_4\;^{2-}$ from anthropogenic source such as a chemical fertilizer. The groundwaters that exceed the recommended limits far agricultural irrigation water contains $23\%\;of\;Cl^-$ reflecting sea-water intrusion, but $50\%\;of\;NO_3^-$ as an anthropogenic pollution, among the wells investigated. In risk assessment of groundwaters by the EC-SAR relationship, only $40\%$ of the groundwaters shows the suitable quality for agricultural irrigation water without any sodium and salinity hazards. Consequently, the pollution sources that cause degradation of groundwater quality in the basin of Seomjin River are the usage of chemical fertilizers and the intrusion of seawater, resulted primarily from the extension of riverward backflow of seawater and secondarily from the overpumping of groundwater.

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.75-79
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• 2000

To investigate seasonal variations of soil solution chemistry, samples were collected from zero tension lysimeters in O, A, and B horizons of 26-year-old Larix leptolepis. Pinus koraiensis and Quercus mongolica stands in Kwangju, Kyunggi Province from September, 1996 through June. 1999. Potassium, $Mg^{2+}$, $Cl^-$, and $No_3\;^-$ concentrations increased in October and November concurrent with inputs of fresh litterfall and twigs. Sodium, $Ca^{2+}$, $K^+$, and $Mg^{2+}$ concentrations increased in March and April concurrent with the yellow sand effect. Potassium concentration showed the highest variation among ions, and $Cl^-$ concentration showed positive correlations with $K^+$ and $Mg^{2+}$ concentrations. Soil solution pH decreased while $Al^{3+}$ and $K^+$ concentrations increased during the study period. If our data reflects long term trends. then $Al^{3+}$ concentration in the O horizon will reach the toxic level (0.180 meq/l) within 10-20 years depending on species.

• Korean Journal of Optics and Photonics
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• v.8 no.1
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• pp.31-36
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• 1997

We measured refractive indices and thicknesses of SiO$_2$ thin films that have been plated on LCD glass substrate for the purpose of preventing the out-diffusion of sodium ions. The best experimental condition to determine refractive index and thickness of SiO$_2$ thin film by using ellipsometry is searched for, where ⅰ) the film thickness is increased uniformly by 20 $\AA$ from 0 $\AA$ to the period thickness while the angle of incidence is fixed and ⅱ) the angle of incidence is increased uniformly by 1$^{\circ}$ from 45$^{\circ}$ to 70$^{\circ}$ while the film thickness is fixed. We estimated the errors in determining the refractive index and thickness by comparing the measurement error of $\Delta$ and Ψ with the calculated one. The ellipsometric constants of SiO$_2$ thin film on LCD glass substrate are measured at several angle of incidence around the Brewster angle, which is the best angle if the experimental error of ellipsometer is not sensitive to the incident angle. Also the best fit refractive index and thickness of SiO$_2$ thin film to these ellipsometric constants measured at several angle of incidenc eas well as the best fit ones to the SE data are obtained using regressional analysis.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.163-171
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• 2009

Subcritical crack growth is one of the main causes of time-dependent fracturing in rock. In the present study, we investigated subcritical crack growth in rock in distilled water (pH = 5.7) and in an aqueous solution of sodium hydroxide (NaOHaq, pH = 12), comparing the results to those in air. We also investigated the effect of the pH in an aqueous environment. We used andesite and granite for all our tests. We determined the relationship between the crack velocity and the stress intensity factor using the double-torsion test under conditions of controlled temperature. We showed that crack velocities in water were higher than those in air, in agreement with other research results indicating that crack velocity increases in water. When we compared our results for NaOHaq with those for water, however, we found that the crack velocity at the same stress intensity factor did not change even though the pH of the surrounding environment was different. This result does not agree with the accepted understanding that hydroxide ions accelerate subcritical crack growth in rocks. We concluded that the pH at the crack tip influences subcritical crack growth, and not the bulk pH, which has little effect.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.91-95
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• 1963

The basic studies of adsorption characteristics of collector on monazite were made by electrophoretic measurement and by determination of the adsorption of some typical flotation collectors. By above measurements made on monazite, it is concluded that $H^+\;and\;OH^-$ are identified to act as potential determining ions and thus the electrical properties of monazite is controlled by the pH of the solution. Therefore, anionic collectors are adsorbed on positively charged surfaces and cationic collectors on negatively charged surfaces, which in turn controls the effective flotation condition with respective collectors for this mineral. These results have been correlated with its flotation behavior obtained by Hallimond tube test.

• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.442-449
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• 2016

The goal of this study is to provide basic data to establish a foundation for the provision of safe drinkable water. The raw water of natural mineral water was analyzed to determine the quantities of anions (F^-, Cl^-, NO_3-N^-, and SO₄^2- ) and cations (Ca²⁺, K⁺, Mg²⁺, and Na⁺) during the former and latter half of 2016. Analysis of the current quality of the raw water of natural mineral water among domestic manufacturers showed average anions contents of 0.46mg/L of fluorine, 8mg/L of chlorine ion, 1.5mg/L of nitrate nitrogen, and 12mg/L of sulfate ion. While the fluorine content was greater than the water quality criterion of 2.0mg/L at four points, the fluorine level was overall stable. The average cations contents included 21.3mg/L of calcium, 1.0mg/L of potassium, 3.4mg/L of magnesium, and 9.6mg/L of sodium. The chemical characteristics were compared among the major ions, and the results are presented in a piper diagram. The content ratio of cations was in the order of Ca²⁺> Na⁺>Mg²⁺>K⁺, whereas that of anions was in the order of SO₄^2->Cl^->NO_3-N^->F^-. While the cations were slightly scattered, the anions were generally concentrated except for at a few points. The Ca-Na-HCO₃ type was dominant overall in water sources from diorite, gneiss, and granite, while the Na-Mg-Ca-HCO₃-Cl type was dominant in basalt sources. Mineral water manufacturers source their water under various conditions, including in-hole casing, excavation depth, and contact state of bedrock; even within the same rocky area, some differences in the water quality type can occur. When the depth of the water source was taken into account, the mean anions contents of F^-, Cl^-, NO_3-N^-, and SO₄^2- were similar, with no significant differences according to depth. Of the cations, K⁺ and Na⁺ showed no significant differences across all the tubular wells, whereas Ca²⁺ and Mg²⁺ decreased in content with depth.