• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.143-153
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• 2012

Mica-type minerals (illites) in the shales of the Jigunsan formation at Seokgaejae in Samchuk-City, Gangwon-do are studied using electron probe micro analysis (EPMA). The average chemical formula of the mica-type mineral obtained from the quantitative analysis is $(K_{1.17}Na_{0.04}Ca_{0.01})(Al_{2.80}Mg_{1.17}Fe_{0.78})(Si_{6.34}Al_{1.66})O_{20}(OH)_4$, which shows a chemical formula within the range of illite. These illites so called can be considered as mixed-phases among muscovite, pyrophyllite and chlorite due to the low contents of interlayer cations and high Mg, Fe. The formula of illite is separated into those three minerals and the method for the separation is newly formulated and proposed in this study. From the formula of illite, the content of muscovite is estimated from K (Na and Ca included), the content of chlorite by Mg+Fe, and the rest remains as pyrophyllite. The chemical formula of muscovite can be calculated by subtracting the compositions of pyrophyllite and chlorite from the analyzed composition of illite using an ideal formula for pyrophyllite and analyzed average formula for chlorite. The calculated formula of muscovite is supposed to be stoichiometric in principle. The result of the separation of analyzed illite is 61% muscovite, 27.3% chlorite and 11.7% pyrophyllite and the calculated formula of muscovite after separation is $(K,Na,Ca)_{2.00}Al_{3.69}(Si_{6.75}Al_{1.25})O_{20}(OH)_4$. The calculated formula of muscovite slightly low in Al content can be considered to be reasonable in general when the low content of Al in the rock and the uncertainties of chlorite compositions used in the calculation are counted. This supports that the method of separation proposed in this study is also applicable.

• Resources Recycling
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• v.26 no.4
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• pp.26-33
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• 2017

The behavior on the solvent extraction of heavy rare earths (HRE) by using PC88A was confirmed to demonstrate the possibility of recovery on the HRE from industrial wastewater, which consist of low concentration rare earth. We verified the extraction behavior of the HRE through a change of equilibrium pH, extractant concentration and A/O ratio, and also confirmed the stripping behavior depending on the type of mineral acids. At equilibrium pH 1.0, extraction of rare earth (RE) was completed from 95% to 100%. In all extraction conditions, it tend to be extracted in order of high atomic number. When A/O ratio was 10/1, Yb and Tm were concentrated at the maximum and increased 6-fold and 3-fold compared to initial concentration, respectively. To confirm the stripping behavior of the RE, three mineral acids were applied to the organic phase and consequently rate of stripping was increased in order of $HNO_3$, $H_2SO_4$ and HCl.

• Analytical Science and Technology
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• v.9 no.4
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• pp.364-372
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• 1996

The sorption and desorption properties of U(VI), Th(IV), Zr(IV), Cu(II), Pb(II), Ni(II), Zn(II), Cd(II) and Mn(II) ions on XAD-16-[2-(2-thiazolylazo)-p-cresol](TAC) chelating resin were studied by elution method for selective separation, concentration and recovery of trace metal ions in sea water. The optimum conditions for the sorption of metal ions were examined with respect to flow rate, pH and concentration of buffer solution. The overall capacities of some metal ions on this chelating resin were 0.41mmol U(VI)/g resin, 0.55mmol Th(IV)/g resin, 0.43mmol Cu(II)/g resin, and 0.32mmol Zr(IV)/g resin, respectively. The elution order of metal ions obtained from breakthrough capacity and overall capacity at pH 5.0 was found as Th(IV)>Cu(II)>U(VI)>Zr(IV)>Pb(II)>Ni(II)>Zn(II)>Cd(II)>Mn(II). Desorption of characteristics for metal ions were investigated with desorption agents such as $HNO_3$, HCl, $HClO_4$, $H_2SO_4$, and $Na_2CO_3$. It was found that most of metal ions except Zr(IV) showed high desorption efficiency with 2M $HNO_3$. But, desorption and recovery of Zr(IV) ion were successfully performed with 1M $H_2SO_4$. The resin was applied for separation and preconcentration of trace amount of U(VI) ion from artificial sea water and the recovery of U(IV) was over 96%.

• Journal of Life Science
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• v.20 no.1
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• pp.77-81
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• 2010

We separated the bacteria showing protease activity from Reticulitermes speratus which is known as the only termite species in Korea. Then, we collected the best activated strain and studied the optimal culture condition for producing the enzyme. According to the results of observing morphological and physiological characteristics, and the type of 16S rRNA of the strain, it was identified as Serratia marcescens and named S. marcescens strain TM-3215. This strain showed the best activity under conditions of 0.8% (w/v) starch, 0.4% (w/v) peptone, 0.08% (w/v) $MgSO_4{\cdot}7H_2O$, $30^{\circ}C$ and pH 8.0. After being cultivated under optimal conditions for 9 hr, the strain produced 19.8 U/ml of enzyme, an amount 1.8 times greater than the control.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.4
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• pp.277-288
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• 2010

The multi-level $H_2O/CO_2$ profile system has been widely used to quantify the storage and advection effects on energy and mass fluxes measured by eddy covariance systems. In this study, we expanded the utility of the profile system by accommodating air sampling devices for isotope analyses of water vapor and $CO_2$. A pre-evacuated 2L glass flask was connected to the discharge of an Infrared Gas Analyzer (IRGA) of the profile system so that airs with known concentration of $H_2O$ and $CO_2$ can be sampled. To test the performance of this sampling system, we sampled airs from 8 levels (from 0.1 to 40 m) at the KoFlux tower of Gwangneung deciduous forest, Korea. Air samples in the 2L flask were separated into its component gases and pure $H_2O$ and $CO_2$ were extracted by using a vacuum extraction line. This novel technique successfully produced vertical profiles of ${\delta}D$ of $H_2O$ and ${\delta}^{13}C$ of $CO_2$ in a mature forest, and estimated ${\delta}D$ of evapotranspiration (${\delta}D_{ET}$) and ${\delta}^{13}C$ of $CO_2$ from ecosystem respiration (${\delta}^{13}C_{resp}$) by using Keeling plots. While technical improvement is still required in various aspects, our sampling system has two major advantages over other proposed techniques. First, it is cost effective since our system uses the existing structure of the profile system. Second, both $CO_2$ and $H_2O$ can be sampled simultaneously so that net ecosystem exchange of $H_2O$ and $CO_2$ can be partitioned at the same temporal resolution, which will improve our understanding of the coupling between water and carbon cycles in terrestrial ecosystems.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.2
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• pp.129-134
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• 1988

Enzymatical properties of Streptomyces sp. S-45 producing chitinase and ${\beta}$-1.3-glucanase isolated from soil were investigated. Chitinase activity was 3.01(U/ml) and ${\beta}$-1.3-glucanase activity was 2.49(U/ml). The optimum medium for mycolytic enzyme production of strain was composed of 0.7% colloidal chitin, 0.3% glucose, 0.5% asparagine, 0.2% peptone, 0.01% NaCl, 0.01% $K_2HPO_4$ and 0.01% $MgSO_4{\cdot}7H_2O$ in intial pH 7.0. The optimal condition for mycolytic enzyme activities were: pH 6.5-7.0, $45-50^{\circ}C$. Enzyme activities were activated by metal ion as $10^{-2}M\;Co^{{+}{+}}$, $Cu^{{+}{+}}$, $Mn^{{+}{+}}$, $Al^{{+}{+}{+}}$ and $10^{-3}M\;Sn^{{+}{+}}$ but $Ag^{{+}{+}}$, $Hg^{{+}{+}}$ inhibited.

• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.159-165
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• 2011

Rosmarinus officinalis extracts had a significant antimicrobial activity against Helicobacter pyori. Total phenolic contents and inhibition zone of rosemary extracts were estimated to be 25.7 mg/g and 14 mm at $200{\mu}g/mL$ of phenolic contents, respectively. The Sephadex LH-20 and MCI-gel CHP-20 column chromatographic separations for the phenolic extracts from R. officinalis leaves led to isolation of five acids, whose structures were determined as protocatechuic acid (A), coumaric acid (B), caffeic acid (C), chlorogenic acid (D), and rosmarinic acid (E), from interpretation of spectroscopic data including nagative fast atom bombardment (FAB)-mass, $^1H$-NMR, $^{13}C$-NMR, and IR. All isolated compounds were tested for antimicrobial activity against H. pyori. The purified single compound showed less antimicrobial activity against H. pylori than the mixed purified compounds, which generate A+B, A+E, C+D, C+E (each $200{\mu}g/disc$) excellent as large clear zone by synergy effect. These results indicate rosemary extracts are preventive agents against H. pyori.

• Resources Recycling
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• v.21 no.6
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• pp.58-64
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• 2012

A study on the solvent extraction for the separation and recovery of Ni and Li from the leaching solution of active cathode materials of Li-ion batteries was investigated using PC88A(2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester). The experimental parameters, such as the pH of the solution, concentration of extractant and phase ratio were observed. Experimental results showed that the extraction percent of Ni and Li and separation factor of Ni/Li were increased with increasing the equilibrium pH. More than 99.4% of Ni and 28.7% of Li were extracted in eq. pH 8.5 by 25% PC88A and the separation factor of Ni/Li was 411.6. From the analysis of McCabe-Thiele diagram, 99% of Ni was extracted by three extraction stages at phase ratio(A/O) of 1.5. Stripping of Ni and Li from the loaded organic phases can be accomplished by sulfuric acid as a stripping reagent and 50-60g/L of $H_2SO_4$ was effective for the stripping of Ni.

• 한국가스학회:학술대회논문집
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• 2005.10a
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• pp.141-145
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• 2005

DME (Di-Methyl Ether) is a new clean fuel and an environmental-friendly energy resource, also is recently increasing with an alternative interest because of the industrial use. DME has been shown to have excellent properties as a diesel fuel giving emission level better than ULEV standard. So it has been attracting considerable as an alternative diesel fuel. In this study, we carried out simulation of separation and purification process of demo plant for 101on per day DME production, which cause the effect that is important in productivity, from operation results of pilot plant for 50kg per day DME production. The liquefied stream, which was separated by gas-liquid separator after DME reactor, includes $CO_2$, DME, Methanol and $H_2O$. We established three distillation columns for separation and purification of the stream. $CO_2$ was extracted from the stream by first distillation column, DME was extracted by second column and Methanol was extracted by third column. We investigated and analyzed the effect which the actual operation variables cause in efficiency of process and optimized process, finally we got the DME of purity $100\%$.

• Textile Coloration and Finishing
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• v.12 no.1
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• pp.25-31
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• 2000

In order to decolorize disperse dyes by using biological treatment process, a strain which has potential ability to degrade disperse dyes was isolated from natural system. To increase the removal efficiency of decolorization in the aqueous solutions, the optimal condition of decolorization by this strain was investigated, and continuous plant test was also developed. The optimal culture conditions of temperature and pH were found to be 4$0^{\circ}C$ and 8.5~9, respectively. When yeast extract was mixed with polypeptone at the mixing ratio of 1:1 as a nitrogen source, decolorization efficiency was highest(93%) among the nitrogen sources. The strain to be screened was excellent to adjust to pH, and it seems to be have ability to control pH needed to growth. The optimal culture conditions in concentration of $MgSO_4\cdot{7H}_2O$ and $KH_2PO_4$ were 0.1%(w/v) and 0.2%(w/v). The result of continuous plant process using wastewater was as following : $COD_{Mn}$ removal efficiency was over than 50%, and this strain was very excellent in decolorization-efficiency for the wastewater of Taegu dyeing complex.