• KSBB Journal
• /
• v.24 no.3
• /
• pp.253-258
• /
• 2009

In this study, the optimization of fabrication conditions was accomplished to make immuno-strip biosensor by the combination of enzyme linked immunosorbent assay (ELISA) and immuno-chromatographic strip techniques for the detection of Escherichia coli O157 : H7. Optimal fabrication conditions of capture antibody concentration, detection antibody concentration, and additive composition of running buffer solution were determined. Optimal concentration was determined as 1.0 mg/mL for both of capture antibody and detection antibody. A composition of 0.5% Tween20 and 3% BSA were selected as optimal additive for buffer solution to prevent non-specific binding.

• Korean Journal of Materials Research
• /
• v.26 no.2
• /
• pp.67-72
• /
• 2016

$BaMoO_4:Tb^{3+}$ phosphor powders were synthesized with different concentrations of $Tb^{3+}$ ions using the solid-state reaction method. XRD patterns showed that all the phosphors, irrespective of the concentration of $Tb^{3+}$ ions, had tetragonal systems with two main (112) and (004) diffraction peaks. The excitation spectra of the $Tb^{3+}$-doped $BaMoO_4$ phosphors consisted of an intense broad band centered at 290 nm in the range of 230-330 nm and two weak bands. The former broad band corresponded to the $4f^8{\rightarrow}4f^75d^1$ transition of $Tb^{3+}$ ions; the latter two weak bands were ascribed to the $^7F_2{\rightarrow}^5D_3$ (471 nm) and $^7F_6{\rightarrow}^5D_4$ (492 nm) transitions of $Tb^{3+}$. The main emission band, when excited at 290 nm, showed a strong green band at 550 nm arising from the $^5D_4{\rightarrow}^7F_5$ transition of $Tb^{3+}$ ions. As the concentration of $Tb^{3+}$ increased from 1 to 10 mol%, the intensities of all the emission lines gradually increased, approached maxima at 10 mol% of $Tb^{3+}$ ions, and then showed a decreasing tendency with further increase in the $Tb^{3+}$ ions due to the concentration quenching effect. The critical distance between neighboring $Tb^{3+}$ ions for concentration quenching was calculated and found to be $12.3{\AA}$, which indicates that dipole-dipole interaction was the main mechanism for the concentration quenching of the $^5D_4{\rightarrow}^7F_5$ transition of $Tb^{3+}$ in the $BaMoO_4:Tb^{3+}$ phosphors.

• Journal of Environmental Science International
• /
• v.5 no.3
• /
• pp.265-275
• /
• 1996

Air pollution characteristics and the influence of sea breeze on surface ozone concentration were studied using the data measured at 7 air quality continuous monitoring stations from June to September using 3 years (1990, 1993, 1994) in Pusan coastal area. Among the 246 sea breeze days for research Period, there were approximately 89 sea breeze days (36%) from lune to September, And there were 120 the episode days (68%) of ozone greater than or equal to 60 ppb in summer season. In 89 sea breeze days, the episode day was highly marked as 56 days (63%). So, we knew that the sea breeze greatly affects the occurence of ozone episode day. the ozone concentration under the condition of the sea breeze increase about 40% in the daytime. Frequencies distribution of $O_3$ concentration for sea breeze moved toward high concentration class. The characteristics of ozone concentration in relation to meteorological conditions of sea breeze is significant because we can discover major weather factors for eastablishing an air pollution- weather forecast system. For further. study about meterological approach method for photochemical air pollution, it is necessary to explain the characteristics of atmosphere below 1, 000 m, especially concerning the formation mechanism of inversion layers. And finally, we will study the relationships to synoptic weather conditions and vertical structure and diurnal variation of local wind systems including sea breeze, and the vertical movements of atmosphere in the city.

• Textile Coloration and Finishing
• /
• v.13 no.4
• /
• pp.264-271
• /
• 2001

Catalytic wet oxidation of ethylene glycol as refractory compound was studied in a batch slurry reactor using lwt% $Pt/A1_2O_3$, lwt% $Pt/TiO_2,\;Mn/CeO_2$(1:1) and 5wt% $Mn/Al_2O_3$. Experiments were conducted to investigate theeffects of temperature, initial ethylene glycol concentration, catalyst dosage and PH on the ethylene glycol decomposition. When compared with the uncatalyzed reaction, the use of catalysts could increase the rate of ethylene glycol decomposition. The lwt% $Pt/A1_2O_3$ catalyst was preferable to the other catalysts for the destructive oxidation of ethylene glycol. The reaction rate was first order with respect to initial concentration of ethylene glycol. In acidic condition the removal efficiency of ethylene glycol was good, but there was a significant leaching of platinum. Small amount of acetic acid, oxalic acid, masonic acid and formic acid as intermediates were detected during catalytic wet air oxidation of ethylene glycol.

• Journal of Environmental Science International
• /
• v.9 no.6
• /
• pp.505-509
• /
• 2000

The purpose of this study was to evaluate the effects of $Ca(OH)_2$ and $CO_2$ additions on the corrosion of metal coupons(ductile iron, galvanized steel, copper and stainless steel). Corrosion rate and released metal ion concentration of ductile iron and galvanized steel decreased by adjusting alkalinity, calcium hardness and pH with $Ca(OH)_2$ & $CO_2$ additions on copper and stainless steel were less than those on ductile iron and galvanized steel. When ductile iron coupon was exposed to water treated with Ca(OH)$_2$&$CO_2$, additions, the main components of corrosion product formed on its surface were $CaCO_3$ and $Fe_2 O_3 or Fe_2 O_4$ which often reduce the corrosion rate by prohibiting oxygen transport to the metal surface.

• Journal of the Korean Chemical Society
• /
• v.7 no.4
• /
• pp.283-287
• /
• 1963

The distribution ratio of hydrogen cupferrate in $H_2O-CHCl_3$ system was considered as a function of pH ($HClO_4$), ionic strength ($NaClO_4$), and cupferron concentration in perchloric acid media, respectively. The values were independent upon pH (1.50∼3.00 range) and ionic strength (0.1∼2.00 range), but they increased as increasing the cupferron concentration in the acidic media. At the infinite dilution, the thermodynamic distribution ratio between chloroform and aqueous phase was 120. 0. The activity coefficients of hydrogen cupferrate in chloroform solution were determined by the distribution ratio. This activity coefficient may be calculated by using the empirical equation, $-log\;f_{CHCl3}=0.1285C_{CHCl3}+{7.775C^2}_{CHCl3}$ which represents the experimental data quite well for the solution in 0.1 mole/l order of hydrogen cupferrate concentration.

• Transactions of the Korean hydrogen and new energy society
• /
• v.18 no.1
• /
• pp.32-39
• /
• 2007

CO oxidation and selective CO oxidation of $La_xCe_{1-x}Co_yCu_{1-y}O_{3-{\alpha}}$ perovskite(x=1, 0.9, 0.7. 0.5; y=1, 0.9, 0.7, 0.5) were investigated. For CO oxidation, catalytic activities were studied according to different preparation conditions such as pH and calcination temperature. The influence of the change of the $O_2$ concentration for selective CO oxidation was studied, too. The substitution of Ce for La improved the catalytic activity for CO oxidation and selective CO oxidation and best activity was observed for $La_{0.7}Ce_{0.3}CoO_3$ prepared at pH 11 and calcined at $600^{\circ}C$. The temperature of 90% CO conversion for CO oxidation using $La_{0.7}Ce_{0.3}CoO_3$ was $230^{\circ}C$. In contrast to the enhancement effect by Ce substitution, the partial substitution of Cu for Co in $LaCo_yCu_{1-y}O_{3-{\alpha}}$ decreased catalytic activities for CO oxidation reaction compared to that using $LaCoO_3$. For selective CO oxidation, the best CO conversion was 66% at $230^{\circ}C$ for $La_{0.7}Ce_{0.3}CoO_3$. The CO conversion of $La_{0.7}Ce_{0.3}CoO_3$ was greatly increased from 66% to 91% as increasing $O_2$ concentration from 1% to 2%.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.E3
• /
• pp.121-127
• /
• 2003

The characteristics of heterogeneous photocatalytic decomposition were investigated at low concentration level of $O_3$on TiO$_2$for various operating parameters such as: loaded catalyst weight (0∼4 mg/$\textrm{cm}^2$), initial concentration of $O_3$(0.06∼10.0 ppm), gas flow rate (1.0 ∼ 2.5ι/min), and relative humidity (0∼80%). This study was conducted using a flow-type reactor at room temperature. Three kinds of pure TiO$_2$(P25, ST -01, and E- 23) were employed as photocatalyts. It was found that $O_3$removal ratio was identical, regardless of the loaded TiO$_2$weight in the range from 0.5 to 4.0 mg/$\textrm{cm}^2$. It was also found that higher initial ozone concentration results in greater oxidation rate of ozone and experimental data show kinetically a good agreement with Langmur-Hinshelwood kinetic model. We also observed that the removal ratio of $O_3$increases linearly with the increasing flow rate and also with the increasing relative humidity for each catalyst.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1565-1568
• /
• 2007

A borate compound was adopted as new host material for $Eu^{3+}$, $Tb^{3+}$ and $Tm^{3+}$ activators. The phosphor samples, $Gd_{1-x}Eu_xCa_3(GaO)_3(BO_3)_4$, $Gd_{1-x}Tb_xCa_3(GaO)_3(BO3)_4$ and $Gd_{1-x}Tm_xCa_3(GaO)_3(BO_3)_4$ have been synthesized by conventional solid-state reaction. The crystalline phase for the resulting powders was identified using an X-ray diffraction $system^1$. Their photoluminescence properties under the excitation of UV ray were investigated. The Eu, Tb or Tm-doped $GdCa_3(GaO)_3(BO_3)_4$ emits efficient red, green or blue light, respectively. It was observed that the optimum concentration of Eu or Tb activator for the borate host was much higher than other $Eu^{3+}$ or $Tb^{3+}-doped$ phosphors.

• Journal of the Korean Geophysical Society
• /
• v.7 no.2
• /
• pp.113-120
• /
• 2004

Hydrochemical characteristics of deep groundwater at Surak-ri, Nonsan-gun, Chungnam Province was explained by major ion concentration, water type, and phase stability diagram. The area is composed of meta-sedimentary rock and quartz pophyry. The 5 boreholes where deep groundwater was sampled and analyzed are located on the meta-sedimentary rocks and drilling depth range of the wells is from 554 m to 928 m. pH, TDS, Na, and SiO2 values are high in the groundwater from meta-sedimentary area intruded by quartz pophyry, while Ca is high in the groundwater from meta-sedimentary area. K and Mg concentrations are low but F concentration is high both groundwater. The content of major anions is in the order of CO3(HCO3)>Cl>SO4(F) in both geology, while that of major cations shows the order of Na>Ca>K(Mg) in meta-sedimentary area intruded by quartz porphyry and a>Na>Mg>Na in meta-sedimentary area. Based on the phase equilibrium in the systems Na2O-Al2O3-SiO2-H2O and K2O-Al2O3-SiO2-H2O, the groundwater is saturated with respect to Quartz and more evolved compared with the natural mineral water. It is concluded that chemical evolution in the groundwater from meta-sedimentary area intruded by quartz porphyry, is nearly saturated with respect to feldspar, while the groundwater from meta-sedimentary area continue to proceed with increasing pH by reaction of feldspar.