• The Korean Journal of Mycology
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• v.16 no.1
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• pp.1-8
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• 1988

Effect of suppression for zoosporangial germination and mycelial growth of Phyto­phthora capsici causing red pepper fruit rot, was carried out in vitro test by using $NH_4OH$ and $KNO_2$, as ammonium/ammonia, nitrite/nitrous acid and $CaCl_2$, as calcium ion. Results of in vitro tests with $NH_4OH$, $KNO_2$, and $CaCl_2$, mol solutions demonstrated that zoosporangial germination of P. capsici was inhibited about 15 to 50% compared with control, according to $NH_3$, HNO as nonionized form and $Ca^{+2}$ ions. Ammonia concentration$(NH_3)$ was proportionally increased by high pH level and mol concentration, whereas low pH and high mol concentration showed rather higher concentration of $HNO_2$. Ammonia were more toxic at pH 8 than at pH 7 under the same concentration, while nitrous acid$(HNO_2)$ was more toxic than at pH 8. The zoosporangial germination inhibition in the ammonium/ammonia and nitrite/nitrous acid solutions demonstrated that $NN_3$, and $HNO_2$, were primarily responsible for the inhibition at lower concentration and mor" toxic by increasing concentration. $Ca^{+2}$ ions showed that zoosporangial germination was inhibitory by high pH level and increasing mol concentration in comparison with buffer conlrol. pH levels affected to mycelial growth of the fungus, and especially, high pH caused rather retardation of mycelial growth. There was no definite inhibitory response of mycelial growth at various degree concentrations of the toxicant solutions.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.479-483
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• 2018

Our group reported the thermal decomposition of R-22 ($CHClF_2$) refrigerants by nitrogen thermal plasma in previous studies. However, it was proposed that the wastewater generated from the end part of the process contains high concentration of fluoride ion which is a component of R-22. The additional post-treatment process to neutralize the $F^-$ ions in the wastewater was investigated in this study. The wastewater generated through the decomposition of R-22 with the same procedure in the previous work was treated using the neutralizer, $Ca(OH)_2$, and the atmospheric pressure plasma jet (APPJ) independently as a post-treatment process. Wastewater samples were collected directly after the treatment for ion-chromatography analysis to trace the change of the concentration of $F^-$ ion in the wastewater. The fluoride concentration in the wastewater showed the highest value when the single water was used as a neutralizer, and the concentration of fluoride in the wastewater was dramatically reduced when the post-treatments were performed.

• YAKHAK HOEJI
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• v.56 no.2
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• pp.108-115
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• 2012

The hyperpolarization-activated current ($I_h$) is an inward cation current activated by hyperpolarization of the membrane potential and plays a role as an important modulator of action potential firing frequency in many excitable cells. In the present study we investigated the effects of extracellular divalent cations on $I_h$ in dorsal root ganglion (DRG) neurons using whole-cell voltage clamp technique. $I_h$ was slightly increased in $Ca^{2+}$-free bath solution. BAPTA-AM did not change the amplitudes of $I_h$. Amplitudes of $I_h$ were decreased by $Ca^{2+}$, $Mg^{2+}$ and $Ba^{2+}$ dose-dependently and voltage-independently. Inhibition magnitudes of $I_h$ by external divalent cations were partly reversed by the concomitant increase of extracellular $K^+$ concentration. Reversal potential of $I_h$ was significantly shifted by $Ba^{2+}$ and $V_{1/2}$ was significantly affected by the changes of extracellular $Ca^{2+}$ concentrations. These results suggest that $I_h$ is inhibited by extracellular divalent cations ($Ca^{2+}$, $Mg^{2+}$ and $Ba^{2+}$) by interfering ion influxes in cultured rat DRG neurons.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.8
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• pp.441-449
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• 2015

Studies on the flocculation of algae using various metal ions were carried out by measurements of optical density(OD) and zeta potential. Cyanobacteria were used as algaes. Flocculation efficiencies of cyanobacteria by an addition of metal ions were determined from OD values, and the effect of metal ions was greater in the order of $Al^{3+}$>$La^{3+}$>$Ho^{3+}$>$Fe^{2+}$>$Ca^{2+}$. Especially for trivalent metal ions, percentages of metal removed from cyanobacteria solutions on flocculation were measured, showing the same order as in flocculation efficiencies. Zeta potentials of cyanobacteria alone were measured with increasing the concentration, found to be all negative voltages, and were increased with increasing the concentration. The effect of pH on zeta potential of cyanobacteria solution was investigated. Below pH 5.5, the zeta potentials were steeply decreased with increasing pH, whereas in the range of $5.5{\leq}pH{\leq}10$ they were almost constant ($-46{\pm}1mV$) even with increasing pH. At a constant concentration of cyanobacteria ($A_{730}=0.25$), an increase in concentration of metal ions caused an increase in zeta potential of cyanobacteria solution, showing that the effect was greater in the order of $Al^{3+}$>$Ho^{3+}$>$La^{3+}{\gg}Mg^{2+}{\geq}Ca^{2+}{\gg}K^+$. At a constant metal concentration, zeta potentials were measured with increasing cyanobacteria concentration, showing that zeta potentials for $K^+$, $Mg^{2+}$ and $Ca^{2+}$ ions were negligibly changed, whereas those of $Ho^{3+}$ and $La^{3+}$ ions were decreased. Moreover, the effect of $Ho^{3+}$ ion on decreasing zeta potential was smaller than that of $La^{3+}$ ion. $Al^{3+}$ ions showed quite a different behavior that with increasing cyanobacteria concentration the zeta potentials increased and decreased thereafter. Hydrolysis of $Al^{3+}$ ions caused a difficulty to investigate coagulation or flocculation of cyanobacteria by measurement of zeta potential.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1111-1115
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• 2008

The characterization of PM$_{2.5}$ and PM$_{10}$ concentration is considered by analysis of ionic and heavy metal component to measured suspended particle at atmosphere in Hoseo university of Asan area. The variation of concentration is studied at the periods of asian dust occured. In asian dust, the PM$_{2.5}$ ratio is decreased from 79.7% to 40.1%, whereas the size-classified mean concentration of suspended particle is increased largely. It is found that the PM$_{2.5}$ ratio is decreased relatively because the coarse particle is increased largely according to the analysis of the mass concentration to divide the fine and coarse particle on 2.1 $\mu$m basis. It is observed that the Ca$^{2+}$ion is about 40 magnifications and Na$^+$, SO$_4{^{2-}}$ ion is increased in sequence in coarse particle, whereas the variation of ionic concentration is slightly increased in the fine particle. Furthermore, Mn, Fe, Zn, and Al are increased in sequence as the result of heavy metal component analysis, and Al is shown the most increased as mass concentration.

• Asian Journal of Atmospheric Environment
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• v.12 no.1
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• pp.67-77
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• 2018

To investigate the effects of forest and the surrounding natural and anthropogenic sources on the bulk depositions on forested land, this study examined differences in ion concentrations between wet-only and bulk samples at two forested sites in Japan. The surrounding natural and anthropogenic sources at each site were different; Shirasaka is in a rural area and Tanashi is an urban environment. The volume weighted (vw) mean concentrations of $K^+$ and $Ca^{2+}$ in the bulk samples were significantly (p<0.05) higher than those in the wet-only samples at both sites. The forest canopy and a nearby incineration plant were hypothesized to be the main sources of $K^+$ contaminants at Shirasaka and Tanashi, respectively. The transport of sea salt and urban dust may explain the presence of enriched $Ca^{2+}$ concentrations in the bulk samples at Shirasaka and Tanashi, respectively. The $NH_4{^+}$ concentrations in the Shirasaka bulk samples were significantly (p<0.05) lower than those in the wet-only samples. The vw mean $SO{_4}^{2-}$ and $NO_3{^-}$ concentrations in both sample types were not significantly different at either site. This study demonstrated that the ion concentration differences between wet-only and bulk samples were affected by nearby natural and anthropogenic sources even at forest sites, similar to previous findings for non-forested locations. However, the $K^+$ concentration differences between wet-only and bulk samples may be higher owing to forest sources, even in the absence of anthropogenic sources.

• Journal of environmental and Sanitary engineering
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• v.6 no.1
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• pp.47-62
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• 1991

Yellow Sand Phenomena was observed from April 8 th to 10 th in 1990. During this period particle was collected to investigate the chacteristics of chemical composition of particulate by High Volume Air Sampler and Andersen Air Sa~npler in Seoul. During this period the particle concentration was 350 yg/$m^3$ and the anions, cations, and metal concentrations were increased and the orders of these were $S0_4\;^{-2}>N0_3\;^->Cl^->F^-, Na^+>Ca^{+2}>NH_4\;^+>Mg^{2+}>K^+$, and Fe>Al>Si>Zn>Pb respectively. The principal source of Yellow Sand were identified soil and sea salt. Mn used by the trace element of soil, the persentage of contribution from soil was calculated to be about 81.3% for the particle increased by Yellow Sand Phenomena. Also the principal chemical compounds of particle were estimate metals(Fe, Al, Si, Zn) oxides, $CaSO_4, NaSO_4, MgSO_4, NaC1, MgCl_2$ and $(NH_4)_2SO_4$.

• Journal of Conservation Science
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• v.2 no.2 s.2
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• pp.25-30
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• 1993

Materials (refractory, stone) of iron making furnace excavated from Kalcheon were investigated by the scanning electron microscopy(SEM) with an energy dispersive X-ray analysis (EDAX), X-ray fluorescence(XRF), and X-ray diffraction(XRD). Chemical composition of the refractory materials were $SiO_2(68.74\%),\;Al_2O_3(18.40\%),\;CaO(0.42\%),\;MgO(1.04\%)\;and\;K_2O(2.26\%)$ in weight ratio, which were the typical components presented in common clay. The results of chemical analysis for the stone and the glaze coated, alkali ion(K, Na, Ca) components of the glaze contained high concentration than that the stone. It was suggested that this change had a close relationship with the kinds of fuels used.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1523-1525
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• 2005

$CaZrO_3:Tb$ as a new green-emitting phosphor, has been synthesized by solid state reaction. Photoluminescence and cathodoluminescence properties for the phosphor with a Perovskite structure were investigated. The $CaZrO_3:Tb$ phosphor, which has several emission peaks due to energy transfer from $^5D_4$ to $^7F_J(J=6,5,4,3)$ of $Tb^{3+}$ ion, exhibited strong green luminescence with the main emission peak centered at 545 nm. Optimum Tb concentration was 0.02mol%.

• Membrane and Water Treatment
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• v.12 no.2
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• pp.59-64
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• 2021

The rejection of sodium chloride (NaCl) and calcium chloride (CaCl2) single salt solutions were carried out for commercial nanofiltration NFDK membrane. Results showed that the NFDK membrane had a negative surface charge and had a higher observed rejection of 93.65% for calcium (Ca2+) ion and 78.27% for sodium (Na+) ions. Prediction of rejection for aqueous solutions of both salts was made using Donnan Steric Pore Model based on Extended Nernst-Planck Equation in addition to concentration polarization film theory. A MATLAB program was developed to execute the model calculations. Absolute Average Relative Error (% AARE) was found below 5% for real rejection of the NFDK membrane. This research could be used successfully to assess the membrane characterization parameter using a proposed procedure which can reduce the number of experiments.