• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.2
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• pp.94-99
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• 2004

This study was conducted to determine the effect of salinity on the growth and development of Korean ginseng (Panax ginseng C.A.Meyer) and to evaluate the inorganic ion content in Korean ginseng with different general complete fertilizer (GCF) and NaCI concentrations at two growth stages. The stem height of Korean ginseng treated with different GCF and NaCI concentrations decreased at the higher EC (2.0 dS m$^{-1}$ ), but there were no significant difference in the stem diameter, the leaf length, and the leaf width among different treatments. The root growth increased with the supply of GCF. Especially, the root growth was facilitated two times at 3.0 dS $\textrm{m}^{-1}$ as compared to control. But the root growth more sharply decreased with NaCI treatment than GCF. The $\textrm{K}^{+}$ and $\textrm{Mg}^{2+}$ content in leaves and roots increased with GCF at the early growth stage. At the late growth stage, the $\textrm{K}^{+}$ content in leaves decreased but the $\textrm{Ca}^{2+}$ and $\textrm{Mg}^{2+}$ content increased. The $\textrm{Ca}^{2+}$ and $\textrm{Mg}^{2+}$ content in roots increased but the $\textrm{K}^{+}$ content decreased. The $\textrm{Na}^{+}$ content in Korean ginseng increased sharply with NaCl treatment. The $\textrm{NO}_3^{-}$ content in leaves and $\textrm{NH}_4^{+}$ content in leaves and roots increased as GCF concentration increased. The $\textrm{NO}_3^{-}$ content in leaves, stems, and roots at the late growth stage decreased as NaCl concentration increased. The $\textrm{NH}_4^{+}$ content in leaves and roots decreased significantly at the early growth stage, but it decreased significantly in leaves and stems at the late growth stage. The root activity of Korean ginseng increased with GCF, but decreased as the EC increased with NaCl. The water potential of leaves with GCF showed no significant difference compare to control, but the water potential of leaves treated with NaCl decreased as EC increased.

• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1733-1741
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• 2020

This study analyzed the effect of meteorological factors on the concentration of PM10 (particulate matter 10) in the atmosphere and the variation of rainwater quality using multivariate statistical analysis. The concentration of PM10 in the atmosphere was continuously measured during eleven precipitation events with a custom-built PM sensor node. A total of 183 rainwater samples were analyzed for pH, EC (electrical conductivity), and water-soluble cations (Na+, Mg2+, K+, Ca2+, NH4+) and anions (Cl-, NO3-, SO42-). The data has been analyzed using two multivariate statistical techniques (principal component analysis, PCA, and Pearson correlation analysis) to identify relationships among PM10 concentrations in the atmosphere, meteorological factors, and rainwater quality factors. When the rainfall intensity was relatively strong (> 5 mm/h, rainfall type 1), the PM10 concentration in the atmosphere showed a negative correlation (r = -0.55, p < 0.05) with cumulative rainfall. The PM10 concentration increased the concentration of water-soluble ions (r = 0.25) and EC (r = 0.4), and decreased the pH (r = -0.7) of rainwater samples. However, for rainfall type 2 (< 5 mm/h), there was no negative correlation between the PM10 concentration in the atmosphere and cumulative rainfall and no statistically significant correlation between the PM10 concentration in the atmosphere and rainwater quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.411-419
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• 1996

The experiment was aimed to determine a change of chemical component in irrigatted water based on different tillage methods and nitrogen rates under mulching of barley straw in direct seeded rice. There was no difference in water pH of no-tillaged plot but high in tillaged plot until 10 days after treatment. The electric conductivity(EC) of the water was higher in no-tillaged plot than in tillaged plot. However, the dissolved oxygen content was vice versa. The content of NH$_4$-N was high in higher application rate of N fertilizer without the tillage. Mean while, NO$_3$-N content was highly affected by no-till aged plot particularly in between application time and fertilizer rate but not in tillaged plot. There was higher in P043- content with the no-tillaged plot compared to the tillaged plot. It was big difference with higher application rate of the fertilizer. Soil cations were high in much application of fertilizer without the tillage.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.121-126
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• 2002

This study was conducted to investigate the effect of high concentration of sodium salts and chlorides in soil on the growth of tomato and the uptake of minerals. The growth inhibition rates of plant height and dry weight were different depending on salts, but they were not related to the electric conductivities (EC) and acidities (pH) in the soil solution. The orders of growth inhibition were Cl, SO$_4$, CO$_3$, PO$_4$＞NO$_3$ in the sodium salts series, and Na, K, Mg, NH$_4$＞Ca in the chlorides. The growth inhibition rates of the sodium salts series tended to be larger than those of the chloride series. Yield was lower 30%~10% in the sodium salt and chloride series than in the control. Chlorophyll content, photosynthetic rate and stomatal conductance were lower in the sodium salts and chloride series than in the control. Mineral concentration was lower in sodium salts and chlorides than in control. The nitrate absorption was inhibited in all salts except for NaNO$_3$ and NH$_4$Cl, and specially in NaCl and Na$_2$SO$_4$ treatments of the sodium salts and in KCl treatment of chloride series. K concentration was reduced NaCl and Na$_2$SO$_4$ treatments compared with the other salts. In the sodium salt series, calcium and magnesium concentration were decreased antagonistically when sodium concentration was increased.

• Journal of the Korean Electrochemical Society
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• v.5 no.3
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• pp.111-116
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• 2002

Electrochemical scanning tunneling microscopy was employed to study the evolution of surface morphology during electrochemical preparation of Si(111)-H from Si(111) oxide. Anodic dark current of cyclic voltammogram in 0.2M $NH_4F$ solution (pH 4.7) decreased as the number of cycles increased and remained nearly constant after the second cycle. Then, the Si(111) oxide was entirely stripped, which was followed by H termination on the Si(111) surface. Hydrides at kink and step sites were etched more rapidly than on the terrace, which remained triangle pits with [112] oriented steps where existed stable monohydride. Then, triangle pits deepened. During chronomamperometry at 0.4V anodic dark current shoulder appeared and decreased slowly, indicated the stripping of Si(111) oxide and the formation of stable (112) oriented steps with monohydride. Additionally, the etching mechanism of Si(111)-H in 0.2M $NH_4F(pH 4.7)$ solution at +0.4V was discussed.

• Economic and Environmental Geology
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• v.55 no.1
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• pp.29-43
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• 2022

The groundwater quality in Boseong area was characterized and their background concentrations were estimated based on the chemical data obtained from 200 groundwater samples collected during July 2019. Groundwater data were classified into two groups: Group 1 with NO₃^- < 44.3 mg/L and Group 2 with NO₃^- ≥ 44.3 mg/L. Results of t-tests indicate that groundwaters in Group 2 are significantly higher in water temperature and Ca concentration and significantly lower in F, As, Pb and Zn concentrations. It was also revealed that groundwaters Group 2 are closely linked to low pH, alkalinity, NH₄, NO₂, F, As, Fe, Mn, Pb and Zn levels, and high EC and water temperature. Background concentrations were estimated using the the BRIDGE method. The results depicted the higher levels in NO₃, NH₄, PO₄, As, Fe, Mn than the ones estimated by MOE and KECO (2018; 2019), which were prepared for the three catchment units in Boseong. The results of this study are believed to have more reliability because more data were used.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.213-236
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• 2001

The ionic composition of soil solution is related to a nutrient uptake by plant. Many models for estimating ionic composition of solution have been developed, and most of them have been used for calculating a content of mineral and ionic species in a geochemical point of view. An approximation model considering both cation and anion in soil solution was developed. Variables such as pH, Eh, EC, cations(K, Ca, Mg. Na, Fe, Mn, Al, $NH_4{^+}$), anions(Si, S, P, CY, $NO_3{^-}$, $HCO_3{^-}$ and chemical equilibria of ionic species in soil solution were input into Excel sheet. The activities of soluble ion, ionpairs and complexes of input element were estimated by Newton-Raphson method using conditional equilibrium constant calculated by Davies equation and special models. Equilibrium contents of insoluble minerals and complexes were also calculated.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.459-464
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• 2016

In this study, the electrochemical characteristics of porous silicon/carbon composite anode were investigated to improve the cycle stability and rate performance in lithium ion batteries. In this study, the effect of TEOS and $NH_3$ concentration, mixing speed and temperature on particle size of nano silica was investigated using $St{\ddot{o}}ber$ method. Nano porous Si/C composites were prepared by the fabrication processes including the synthesis of nano $SiO_2$, magnesiothermic reduction of nano $SiO_2$ to obtain nano porous Si by HCl etching, and carbonization of phenolic resin. Also the electrochemical performances of nano porous Si/C composites as the anode were performed by constant current charge/discharge test, cyclic voltammetry and impedance tests in the electrolyte of $LiPF_6$ dissolved inorganic solvents (EC:DMC:EMC=1:1:1vol%). It is found that the coin cell using nano porous Si/C composite has the capacity of 2,006 mAh/g and the capacity retention ratio was 55.4% after 40 cycle.

• Korean Journal of Environmental Agriculture
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• v.21 no.3
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• pp.165-171
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• 2002

A study was conducted to investigate the seasonal changes in water quality of watershed in the Agricultural Environment Promotion Zone. Samples collected were 12 GW (ground water), 2 IW (irrigation water), 2 SW (stream water) in An-Dong City, 4 GW, 6 IW, 11 SW in Young-Yang Gun, and sampling was conducted separately during dry and rainy season. In the ground water, EC and ionic species, except pH, were higher than those in stream water, and especially $NO_3-N$ concentration exceeded the limitation of drinking water. Concentration of ions decreased as the sampling depth was far from the soil surface. During a rainy season, the concentrations of $NO_3-N$ and K in the stream water were slightly higher than those during season. COD was lower during dry season in Yong-Yang, while the trend was contrasted to An-Dong. These results suggest that ground water was polluted by fertilization and compost while streamwater was polluted by loss of soil and organic during the rainy season. Principal chemical components related with changing water quality were EC, $NO_3^-$, Ca, Mg, Na, $Cl^-$, $Cl^-$, $SO_4^-$ in ground water, whereas $NH_4-N$, K, Mg, $Cl^-$, $SO_4^-$ in stream water.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.604-613
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• 2006

The chemical composition of $PM_{2.5}$ such as ${SO_4}^{2-},\;{NO_3}^-,\;Cl^-,\;{NH_4}^+,\;Ca^{2+},\;K^+,\;Na^+,\;Mg^{2+}$, OC, and EC and the concentrations of reactive trace gases including $O_3,\;CO,\;NOx,\;SO_2,\;and\;H_2O_2$ were measured at Gosan in Jeju Island during March $13{\sim}30$, as a part of the Atmospheric Brown Clouds-East Asian Regional Experiment 2005(ABC-EAREX2005). The average mass concentrations of $PM_{2.5}$ was 27.3 ${\mu}g/m^3$, of which OC showed the highest concentration as 4.22 ${\mu}g/m^3$ and nss ${SO_4}^{2-}$ was the second highest as 3.34 ${\mu}g/m^3$. During that period, average concentrations of CO and $O_3$ was about 300 ppbv and 56 ppbv, respectively. For the whole experiment, the correlations of CO with ${SO_4}^{2-}$ and EC were very good, which suggests that CO can be used as tracer for the formation of fine aerosols. Several pollution and dust episodes were identified by the enhancement of CO, OC, EC, nss ${SO_4}^{2-},\;or\;Ca^{2+}$ concentrations or their ratios. In conjunction with factor analysis, air trajectory analysis, and comparison with emission inventories, these results indicate the spring aerosols collected at Gosan was strongly influenced by Asian outflows.