• Journal of Soil and Groundwater Environment
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• v.21 no.6
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• pp.179-191
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• 2016

In addition to the measurement of the concentration of soil contaminants, the new idea of indicative parameters was proposed to validate the remedial works through the monitoring for the changes of soil characteristics after applying the clean up technologies. The parameters like CFU (colony forming unit), pH and soil texture were recommended as indicative parameters for land farming. In case of soil washing, water content and the particle size distribution of the sludge were recommended as indicative parameters. The sludge is produced through the particle separation process in soil washing and it is usually treated as a waste. The parameters like water content, organic matter content, CEC (cation exchange capacity) and CFU were recommended as indicative parameters for the low temperature thermal desorption method. Besides the indicative parameter, sampling methods in stock pile and the optimal minimum amount of composite soil sample were proposed. The rates of sampling error in regular grid, zigzag, four bearing, random grid methods were 17.3%, 17.6%, 17.2% and 16.5% respectively. The random grid method showed the minimum sampling error among the 4 kinds of sampling methods although the differences in sampling errors were very little. Therefore the random grid method was recommended as an appropriate sampling method in stock pile. It was not possible to propose a value of optimal minimum amount of composite soil sample based on the real analytical data due to the dynamic variation of $CV_{fund{\cdot}error}$. Instead of this, 355 g of soil was recommended for the optimal minimum amount of composite soil sample under the assumption of ISO 10381-8.

• Asian Journal of Atmospheric Environment
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• v.6 no.1
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• pp.53-66
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• 2012

A comparison of analytical approaches for Levoglucosan ($C_6H_{10}O_5$, commonly formed from the pyrolysis of carbohydrates such as cellulose) and used for a molecular marker in biomass burning is made between the four different analytical systems. 1) Spectrothermography technique as the evaluation of thermograms of carbon using Elemental Carbon & Organic Carbon Analyzer, 2) mass spectrometry technique using Gas Chromatography/mass spectrometer (GC/MS), 3) Aerosol Mass Spectrometer (AMS) for the identification of the particle size distribution and chemical composition, and 4) two dimensional Gas Chromatography with Time of Flight mass spectrometry (GC${\times}$GC-TOFMS) for defining the signature of Levoglucosan in terms of chemical analytical process. First, a Spectrothermography, which is defined as the graphical representation of the carbon, can be measured as a function of temperature during the thermal separation process and spectrothermographic analysis. GC/MS can detect mass fragment ions of Levoglucosan characterized by its base peak at m/z 60, 73 in mass fragment-grams by methylation and m/z 217, 204 by trimethylsilylderivatives (TMS-derivatives). AMS can be used to analyze the base peak at m/z 60.021, 73.029 in mass fragment-grams with a multiple-peak Gaussian curve fit algorithm. In the analysis of TMS derivatives by GC${\times}$GC-TOFMS, it can detect m/z 73 as the base ion for the identification of Levoglucosan. It can also observe m/z 217 and 204 with existence of m/z 333. Although the ratios of m/z 217 and m/z 204 to the base ion (m/z 73) in the mass spectrum of GC${\times}$GC-TOFMS lower than those of GC/MS, Levoglucosan can be separated and characterized from D (-) +Ribose in the mixture of sugar compounds. At last, the environmental significance of Levoglucosan will be discussed with respect to the health effect to offer important opportunities for clinical and potential epidemiological research for reducing incidence of cardiovascular and respiratory diseases.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.3
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• pp.237-250
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• 2013

At Gosan ABC superstation in Jeju Island, we measured organic carbon (OC) and elemental carbon (EC) in $PM_{2.5}$ from October 2009 to June 2010 using a Sunset Laboratory Model-4 Semi-Continuous OC/EC Field Analyzer. It employs TOT (Thermal-Optical-Transmittance) method with NIOSH 5040 protocol and enables to continuously monitor OC and EC concentrations with 1-hour time resolution. The mean values of OC and EC for the entire period of measurements were $2.1{\pm}1.4{\mu}g/m^3$ and $0.7{\pm}0.6{\mu}g/m^3$, respectively. The OC/EC ratio was 3 and EC accounted $25{\pm}2.1%$ of total carbon (TC, TC=OC+EC). Although OC and EC showed similar trend in seasonal variation, the ratio of OC to EC was the highest in early summer when temperature was the highest and the air was affected by biomass burning in the southern part of China. In winter, the high OC and EC concentrations were likely influenced by increased coal combustion from residential heating. The high OC and EC concentrations were observed during events such as haze, dust, and the combination of the two. During the haze events, OC and EC were enhanced with increase in $PM_{10}$, $PM_{2.5}$, $SO_2$, and $NO_2$ with broad maxima. When dust occurred, both OC and EC started decreasing after reaching their maxima a couple of hours before $PM_{10}$ maximum. The peak separation of carbonaceous species and aerosol masses with time was more noticeable when haze event was followed by dust plume. These results confirm that OC and EC are key components of haze occurring in the study region.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.4
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• pp.325-332
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• 2013

Pyroporcessing of spent nuclear fuel generates a considerable amount of LiCl-KCl eutectic waste salt containing radioactive rare earth (RE) chlorides. In this study, a series of processes, which consist of a phosphorylation/distillation process and a solidification process, were performed to minimize volume of the LiCl-KCl eutectic waste salt and solidify a residual waste into a stable form at a relatively low temperature. Over 99wt% of RE chlorides in LiCl-KCl eutectic salt was converted and separated into $REPO_4$ in the phosphorylation/distillation process using a mixture of $Li_3PO_4-K_3PO_4$. The separated $REPO_4$ was solidified into a homogeneous and fine-grained form at $1,050^{\circ}C$ using LIP(Lead Iron Phosphate) as a solidification agent. The final waste volume was reduced below about 10% through the series of the processes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.163-170
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• 2008

The reductive stripping of Np using a n-butyraldehyde (NBA) from loaded organic solution containing Np, which was oxidative-extracted in a system of a 30 % TBP/NDD-2M $HNO_3$ and O/A=2 containing 0.005 M $K_2Cr_2O_7$ as an oxidant of Np, was studied. The stripping yields of Np was increased with an increasing the NBA concentration, with a decreasing the nitric acid concentration of stripping solution and with a decreasing the reaction temperature. The apparent reductive stripping rate equation was shown by the following equation : $-d[Np]_{Org.}/dt$ = 1,524 exp(-2,906/T) $[NBA]^{0.91}\;[H^+]^{-0.92}[Np]_{Org.}$. At 1.04 M NBA and 2 M $NHO_3$, the stripping yield of Np and U was 70.1 %, and 7.1 %, respectively, and the separation factor of U over Np ($=D_U/D_{Mp}$) was about 30.4. Therefore, it was found that U and Np co-extracted in a system of TBP-$HNO_3$ could be effectively mutual-separated by the NBA.

• Journal of the Korean Chemical Society
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• v.23 no.4
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• pp.217-236
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• 1979

The author's theory for plastic deformation was applied to superplastic alloys (Zn-Al eutectoid, Al-Cu, Pb-Sn, Sn-Bi, Mg-Al eutectics). The plastic deformation of the superplastic alloys could be described by two Maxwell models connected in parallel which represent two grain boundary flow units. The flow units are characterized by the two parameters $X_{gj}/{\alpha}_{gj}\;and\;{\beta}_{gj}$ (j=l or 2, g signifies the grain boundary) the values of which were obtained by applying our flow equation [Eq. (5)] to experiment. We confirmed that our flow equation describes the superplasticity very well. The curve of strain rate sensitivity m (=${\partial}\;In\;f/{\partial}\;In\;\dot{s})\;vs.\;-In\dot{s}$, where f and s are stress and strain rate, respectively, showed two peaks corresponding to flow unit gl and g2, the separation of the two peaks is determined by the difference between ${\beta}_{g1}\;and\;{\beta}_{g2}$. The condition of superplasticity is also determined by ${\beta}_{gj}$, which satisfies $\dot{s}_{mj}{\leqslant}1.53}{\beta}_{gj}$ [Eq.(13)], where $\dot{s}_{mj}$ is the s of the jth unit at the peak. The grain size dependence of ${\beta}_{gj}$ is described by $ln({\beta}_{gj})^{-1}$=alnx+b [Eq. (16)], where x is the grain size, and a and b are constants. The activation enthalpy for each flow unit, ${\Delta}H_{gj}^{\neq}$ was also determined from the temperature dependence of ${\beta}_{gj}$ which is proportional to the relaxation time of the j th unit. Since the superplasticity is determined by Eq. (13), and since ${\beta}_{gj}$ and ${\Delta}H_{gj}^{\neq}$ are related, we obtained the conclusion that superplasticity occurs in the system having small ${\Delta}H_{gj}^{\neq}$ values. The Aej values were equal to the activation enthalpies of grain boundary self-diffusion of the component atoms of the alloys, this accords with our proposed flow mechanism. The ${\Delta}H_{gj}^{\neq}$ value increases with grain size as expected from Eq. (16).

• Journal of the Korean Magnetics Society
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• v.10 no.3
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• pp.133-138
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• 2000

We have investigated some crystallographic, magnetic, and transport properties of the first colossal magnetoresistive compounds $La_{1-x}Ba_{x}MnO_3(0\leq\chi\leq$1)$(5\;K\leqT\leq360K,-5T\leqH\leq5T$ and resistivity $(100K\leqT\leq350K$measurements. $La_{1-x}Ba_{x}MnO_3$ were found to be ferromagnetic for all x.The $La_{1-x}Ba_{x}MnO_3$were found to be insulating for x< 0.2, metallic for 0.20.5. The magnitude of saturation magnetization (Ms) increased until x=1/8 and had theoretical maximum Ms for 0.13$\sfrac{3}{8}$ and had a constant value of 335~340 K for x>$\sfrac{3}{8}$. For $x\geq0.5$ the $La_{1-x}Ba_{x}MnO_3$ samples showed a percolation-type conduction behavior and enhanced low field magnetoresistance caused by simultaneous occurrence of the chemical/magnetic phase separation.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.2
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• pp.107-115
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• 1993

Procedures to separate motile. normal & motile and acrosome-reacted sperm with high efficiency have clinical application in Assisted Reproductive Technology in terms of increasing the probability of fertilization by a normal sperm and subsequent normal embryonic development. This study evaluated the effects of 10 sperm preparation techniques [Swim-up from a washed pellet (SU). Swim-up from semen (SO). Continuous Percoll Gradients I (PIC). Discontinuous Percoll Gradients I (PID). Continuous Percoll Gradients II(P II C). Discontinuous Percoll Gradients II(P II D), SpermPrep (SFC). Wang's tube (WT). Albumin Gradients (AG), Low temperature capacitation (LTC)] on motility (%), normal morphology (%), motile sperm recovery rate(%). morphologically normal & motile sperm recovery rate (%), true acrosome reaction (%) and fertilizing ability. A P II D proved to be an effective means of separating morphologically normal & motile sperm. Our results indicated the P II D has advantages as compared with other methods in terms of recovery rate. enhancement of motility and normal morphology. And a LTC seems to be an effective means of enhancing the true acrosome reaction and fertilizing ability. These results suggest that the combined method of LTC and P II D for separation of morphologically normal & motile sperm and acrosome reacted sperm may be a useful procedure for intrauterine insemination and in vitro fertilization in the management of male factor infertility as well as for isolation of subpopulation of sperm for basic research.

• Clean Technology
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• v.26 no.1
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• pp.30-38
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• 2020

The kinetic and thermodynamic parameters of Acid Red 66, adsorbed by granular activated carbon, were investigated on areas of initial concentration, contact time, and temperature. The adsorption equilibrium data were applied to Langmuir, Freundlich, Temkin, Redlich-Peterson, and Temkin isotherms. The agreement was found to be the highest in the Freundlich model. From the determined Freundlich separation factor (1/n = 0.125 ~ 0.232), the adsorption of Acid Red 66 by granular activated carbon could be employed as an effective treatment method. Temkin's constant related to adsorption heat (B_T = 2.147 ~ 2.562 J mol^-1) showed that this process was physical adsorption. From kinetic experiments, the adsorption process followed the pseudo-second order model with good agreement. The results of the intraparticle diffusion equation showed that the inclination of the second straight line representing the intraparticle diffusion was smaller than that of the first straight line representing the boundary layer diffusion. Therefore, it was confirmed that intraparticle diffusion was the rate-controlling step. From thermodynamic experiments, the activation energy was determined as 35.23 kJ mol^-1, indicating that the adsorption of Acid Red 66 was physical adsorption. The negative Gibbs free energy change (ΔG = -0.548 ~ -7.802 kJ mol^-1) and the positive enthalpy change (ΔH = +109.112 kJ mol^-1) indicated the spontaneous and endothermic nature of the adsorption process, respectively. The isosteric heat of adsorption increased with the increase of surface loading, indicating lateral interactions between the adsorbed dye molecules.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.430-437
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• 1997

Uranyl-peroxide compound was prepared by the reaction of excess hydrogen peroxide solution and trace uranium in filtrate from nuclear fuel conversion plant. The $CO_3{^{2-}}$ in filtrate was removed first by heating more than $98^{\circ}C$, because uranyl-peroxide compound could not be precipitated by $CO_3{^{2-}}$ remaining in filtrate. The optimum condition for uranyl-peroxide compound was ageing for 1 hr after controling the pH with $NH_3$ gas and adding the excess $H_2O_2$ of 10ml/lit.-filtrate. Uranium concentration in the filtrate was appeared to 3 ppm after the precipitation of uranyl-peroxide compound, and the chemical composition of this compound was analyzed to $UO_4{\cdot}2NH_4F$ with FT-IR, X-ray diffractometry, TG and chemical analysis. Also, this fine particle, about $1{\sim}2{\mu}m$, could be grown up to $4{\mu}m$ at pH 9.5 and $60^{\circ}C$. The separation efficiency of precipitate from mother liquor was increased with increase of pH and reaction temperature. Otherwise, the crystal form of this particle showed octahedral by SEM and XRD, and $U_3O_8$ powder was obtained by thermal decomposition at $650^{\circ}C$ in air atmosphere.