• Journal of Ecology and Environment
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• v.37 no.3
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• pp.131-137
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• 2014

To investigate the solute pattern of salt marsh plants in Suncheon Bay in Korea, plants and soil samples were collected at three sites from July to September 2011. The soil pH around the investigated species was weakly alkaline, 6.9-8.1. The total ion and Cl- content of site 1 gradually increased, while those of site 2 and site 3 were lowest in August and highest in September. The exchangeable $Ca^{2+}$, $Mg^{2+}$ and $K^+$ in the soil were relatively constant during the study period, but the soil exchangeable $Na^+$ content was variable. Carex scabrifolia and Phragmites communis had constant leaf water content and very high concentrations of soluble carbohydrates during the study period. However, Suaeda malacosperma and S. japonica had high leaf water content and constant very low soluble carbohydrate concentrations. Carex scabrifolia accumulated similar amounts of $Na^+$ and $K^+$ ions in its leaves. Phragmites communis contained a high concentration of $K^+$ ions. Suada japonica and S. malacosperma had more $Na^+$ and $Cl^-$ ions than $K^+$ ions in their leaves. Suaeda japonica had higher levels of glycine betaine in its leaves under saline conditions than C. scabrifolia and P. communis. Consequently, the physiological characteristics of salt marsh chenopodiaceous plants (S. japonica and S. malacosperma) were the high storage capacity for inorganic ions (especially alkali cations and chloride) and accumulation of glycine betaine, but monocotyledonous plant species (C. scabrifolia and P. communis) showed high $K^+$concentrations, efficient regulation of ionic uptake, and accumulation of soluble carbohydrates. These characteristics might enable salt marsh plants to grow in saline habitats.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.235-242
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• 2005

This study is on the evaluation of performance of polymer cement mortar which is used for pre-wetting spray method. Pre-wetting spray method is an epoch-making method to repair concrete structures damaged, which is added a small quantity water preciously to dry mortar to reduce dust and rebound and spray mortar mixed with fixed quantity water at nozzle before spray. The result showed that physical performance such like compressive, flexural and adhesive strength of polymer cement mortar, TS 100 used for pre-wetting spray method was superior to other repair mortar. Also durable performance such as resistance on permeability of chloride ion, carbonation, chemical and freezing-thawing was excellent.

• Bulletin of the Korean Chemical Society
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• v.27 no.6
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• pp.835-840
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• 2006

Dimethyl 1-(4-nitrobenzoyl)-8-oxo-2,8-dihydro-1H-pyrazolo[5,1-a]isoindole-2,3-dicarboxylate has been used as an ionophore and o-nitrophenyloctyl ether as a plasticizer in order to develop a poly(vinyl chloride)-based membrane electrode for calcium ion detection. The sensors exhibit significantly enhanced response towards calcium(II) ions over the concentration range $8.0{\times}10^{-7}\;1.0{\times}10^{-1}$ M at pH 3.0-11 with a lower detection limit of $5.0 {\times}10^{-7}$ M. The sensors display Nernstian slope of 29.5 ${\pm}$ 0.5 mV per decade for Ca(II) ions. Effects of plasticizers, lipophilic salts and various foreign common ions are tested. It has a fast response time within 10 s over the entire concentration range and can be used for at least 2 months without any divergence in potentials. The proposed electrode revealed good selectivity and response for $Ca^{2+}$ over a wide variety of other metal ions. The selectivity of the sensor is comparable with those reported for other such electrodes. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a Ca(II) solution, with EDTA.

• Corrosion Science and Technology
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• v.2 no.5
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• pp.212-218
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• 2003

Electronic properties of passive films formed on Ti at film formation potentials $(E_f)V_{SCE}$ in pH 8.5 buffer solution and in an artificial seawater were examined through the photocurrent measurement and Mott-Schottky analysis. The passive films formed on Ti in pH 8.5 buffer solution exhibited a n-type semiconductor with a band gap energys $(E_g);E_g^{n=2}=3.4$ eV for nondirect electron transition, and $E_g^{n=0.5}=3.7$ eV for direct electron transition. These band gap values were almost same as those for the passive films formed in artificial seawater, indicating that chloride ion ($Cl^-$ in solution did not affect the electronic structure of the passive film on Ti. $E_g$ for passive films formed on Ti were found to be greater than those ($E_g^{n=0.5}=3.1$ eV, $E_g^{n=2}=3.4$) for a thermal oxide film formed on Ti in air at $400^{\circ}C$. The disorder energy of passive film, determined from the absorption tail of photocurrent spectrum, was much greater than that for the thermal oxide film farmed on Ti in air at $400^{\circ}C$. The greater $E_g$ and the higher disorder energy for the passive film compared with those for the thermal oxide fIlm suggest that the passive film on Ti exhibited more disorded structure than the thermal oxide film. The donor density (about $2.4{\times}10^{20}cm^{-3}$) for the passive film formed in artificial seawater was greater than that (about $20{\times}10^{20}cm^{-3}$) formed in pH 8.5 buffer solution, indicating that $Cl^-$ increased the donor density for the passive film on Ti.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.317-327
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• 2017

The addition of different types of polymers such as SBR, VAE, Acrylic, etc. in concrete and mortar leads to an increase in compressive, tensile and bond strength and decrease in permeability of polymer modified mortar (PMM) and concrete (PMC). The improvement in properties such as bond strength and impermeability makes PMM/PMC suitable for use as repair/retrofitting and water proofing material. In the present study effect of addition of fluoropolymer on the strength and permeability properties of mortar has been studied. In the cement mortar different percentages viz. 10, 20 and 30 percent of fluoropolymer by weight of cement was added. It has been observed that on addition of fluoropolymer in mortar the workability of mortar increases. In the present study all specimens were cast keeping the workability constant, i.e., flow value $105{\pm}5mm$, by changing the amount of water content in the mortar suitably. The specimens were cured for two different curing conditions. Firstly, these were cured wet for one day and then cured dry for 27 days. Secondly, specimens were cured wet for 7 days and then cured dry for 21 days. It has been observed that compressive strength and split tensile strength of specimens cured wet for 7 days and then cured dry for 21 days is 7-13 percent and 12-15 percent, respectively, higher than specimens cured one day dry and 27 days wet. The sorptivity of fluoropolymer modified mortar decreases by 88.56% and 91% for curing condtion one and two, respectively. However, It has been observed that on addition of 10 percent fluoropolymer both compressive and tensile strength decreases, but with the increase in percentage addition from 10 to 20 and 30 percent both the strengths starts increasing and becomes equal to that of the control specimen at 30 percent for both the curing conditions. It is further observed that percentage decrease in strength for second curing condition is relatively less as compared to the first curing condition. However, for both the curing conditions chloride ion permeability of polymer modified mortar becomes very low.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.117-124
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• 2018

BACKGROUND: Oxycarboxin(5,6-dihydro-2-methyl-N-phenyl-1,4-oxathiin-3-carboxamide-4,4-dioxide) as oxanthiin is a systemic fungicide commonly used for control of various pathogens in agronomic and horticultural crops. In an effort to develop an analytical method to trace the fungicide, a method using HPLC equipped with UVD/MS was studied. METHODS AND RESULTS: Oxycarboxin was extracted with acetone from hulled rice, soybean, Kimchi cabbage, green pepper, and apple samples. The extract was diluted with saline water, followed by liquid-liquid extraction with methylene chloride. Florisil column chromatography was employed for the purification of the extracts. Oxycarboxin was determined on a Zorbax SB-AQ $C_{18}$ column by HPLC with UVD. Accuracy of the proposed method was validated by the recovery tests from crop samples fortified with oxycarboxin at 3 levels per crop. CONCLUSION: Mean recoveries ranged from 78.3% to 96.1% in five representative agricultural commodities. The coefficients of variation were less than 10%, and limit of quantitation of oxycarboxin was 0.04 mg/kg. A confirmatory technique using LC/MS with selected-ion monitoring was also provided to clearly identify the suspected residue. The method was reproducible and sensitive to determine the residue of oxycarboxin in agricultural commodities.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.4
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• pp.347-361
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• 2003

Sulfur dioxide (SO$_2$), ozone, total suspended particulates (TSP) and PM$_{2.5}$ were measured at Deokjeok Island in the Yellow Sea during April 1999 to June 2000. Although the emission amount of air pollutants is quite low in this small island of 36 km$^2$ with 1.4 thousand inhabitants, there are pollutant sources such as an oil -firing power plant and a wharf for ferryboat. The island is also influenced from the emissions from the greater Seoul area in the east and from China in the west. In order to characterize the pollutant variations due to interactions between transport and local emissions. the correlation between variations of SO$_2$ and ozone was investigated. Mass and ion concentrations of TSP and PM$_{2.5}$ were examined on selected episode days of positive and negative correlations between the two gaseous species in spring and winter. The effects of transport were pronounced on the days of positive correlation in spring with higher concentrations of ozone and PM$_{2.5}$. TSP concentrations were also high on these days because of high wind speeds. On the days of negative correlation in spring, frequent fog associated with low wind speeds facilitated SO$_2$ oxidation and increased sulfate accompanied with decrease in nitrate in PM$_{2.5}$ and chloride in TSP. This latter phenomena was noticeable since it showed that chemical composition of fine particles could be significantly altered not only during the transport but also by local environment.ronment.

• The Korean Journal of Pharmacology
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• v.25 no.1
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• pp.59-66
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• 1989

To determine the relation between cGMP and ion reabsorption in rat medullary thick ascending limb of Henle's loop (mTALH) the effects of loop diuretics, furosemide and ethacrynic acid, on the guanylate cyclase of rat mTALH were investigated. The interactions between loop diuretics and cyclooxygenase inhibitors, aspirin and indomethacin, on guanylate cyclase of rat mTALH were also investigated. Furosemide and ethacrynic acid increased guanylate cyclase activity and these effects were not inhibited by aspirin or indomethacin. Arachidonic acid potentiated the stimulatory effect of furosemide on guanylate cyclase. These results suggest that furosemide and ethacrynic acid activate guanylate cyclase directly, and in addition, furosemide affects indirectly via prostaglandin. The reabsorption of sodium chloride may be, at least partially, controlled by cGMP in mTALH.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.660-667
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• 2002

The effects of polymer-cement ratio and antifoamer content on the durability of ultrarapid-hardening polymer-modified mortars using redispersible polymer powder are examined. As a result, regardless of the antifoamer content, the setting time of the ultrarapid-hardening polymer-modified mortars using redispersible polymer powder tend to delay with increasing polymer-cement ratio. The water absorption and chloride ion penetration depth of the ultrarapid-hardening polymer-modified mortars using redispersible polymer powder decrease with increasing polymer-cement ratio and antifoamer content. The resistance of freezing and thawing and chemicals improvement is attributed to the improved bond between cement hydrates and aggregates because of the incorporation of redispersible polymer powder

• Analytical Science and Technology
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• v.7 no.1
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• pp.65-78
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• 1994

The herbicide mixture of 7 triazines and 9 phenoxyalkanoic acid esters was simultaneously separated and determinated with the selected ion monitoring by using gas chromatography/mass spectrometry. The extraction recoveries of those herbicides from the reagent water were studied for the organic solvent extraction(LLE) with methylene chloride. The calibration curves of them showed good linearity over the concentration range of 0.2~0.5ng/ml and the detection limits were 0.2~0.5ng/ml for 100ml of water. This analytical method could be applied to the drinking water and biological sample.