• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.583-588
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• 2003

Cation exchange capacity of clay, white clay and zeolite was measured by the adsorption test for 3 different heavy metal (Cd, Cr, Zn) standard solutions whose concentrations were varied by 10, 20, 30 ppm and pH were varied by 3, 5, 7, 9, respectively. The adsorption rate of Cd and Zn increased with increasing pH and slowly increased with increasing pH above pH 5. However, adsorption rate of Cr did not increase with increasing pH. Especially, Cr adsorption rate of the mixture of clay and white clay at pH 5 showed an half decrease compared to that at pH 3. The adsorption rate of mixed heavy metal solutions was in the order of Cd, Zn > Cr; however, the order was changed by Fe>Pb, Cu>Cr>Zn>Cd in case of Cu, Fe and Pb addition.

• Economic and Environmental Geology
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• v.43 no.6
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• pp.573-587
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• 2010

Bioleaching experiments were effectively carried out at $42^{\circ}C$, $52^{\circ}C$ and $62^{\circ}C$ to leach the more valuable metal ions from sphalerite using bacteria. The pH values of the bioleaching solution were constantly maintained for 10 days in the range of 2.40 to 2.55. In these bioleaching experiments, rod-shaped bacteria attached to the sphalerite surface were continuously observed in the sample. Along with the increase in the leaching temperatures, the concentration of Zn and Pb increased in the control sample of leachates, whereas the concentration of Fe increased in the sample containing bacteria. At $42^{\circ}C$, $52^{\circ}C$ and $62^{\circ}C$ the biological leaching content of Zn was found to be 9.5, 2.8 and 2.9 times higher than that in the chemical leaching content, respectively. At these temperatures, the content of Pb in the bacterial sample of the leachate was detected to be 14.8, 7.4 and 3.8 times higher than that of the control sample of the leachate, respectively.

• The Korean Journal of Mycology
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• v.21 no.1
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• pp.23-27
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• 1993

Ion effects on $11{\alpha}-hydroxylation$ of progesterone and $5{\alpha}-reduction\;of\;11{\alpha}-hydroxyprogesterone$ by Rhizopus nigricans were investigated. Metal ions such as $Cu^{2+},\;Cd^{2+},\;Co^{2+},\;Mn^{2+},\;Zn^{2+},\;Fe^{2+},\;Mg^{2+},\;Fe^{3+}\;and\;Na^+$ reduced the $11{\alpha}-hydroxylation$ activity, while $K^+$ stimulated the same reaction. Enzyme activity for the $5{\alpha}-reduction$ of $11{\alpha}-hydroxyprogesterone$ was increased in the presence of $Fe^{2+},\;Mn^{2+},\;Mg^{2+},\;Co^{2+},\;Zn^{2+},\;Fe^{3+},\;K^+\;and\;Na^+$, whereas it was decreased in the presence of $Cd^{2+}\;and\;Cu^{2+}$. Potassium ion of $10^{-3}\;M\;$ of concentration was found to be effective for the promotion of $11{\alpha}-hydroxylation$. On the other hand, cadmium ion of $10^{-4}\;M$ was proved to suppress the $5{\alpha}-reduction$ reaction. Progesterone is reported to be transformed into $11{\alpha}-hydroxyprogesterone$ which, in turn, is converted further into $11{\alpha}-hydroxy-allopregnane-3$, 20-dione by R. nigricans. From this point of view, the highest yield of $11{\alpha}-hydroxyprogesterone$ could be obtained when potassium ion of $10^{-3}\;M$ was given initially followed by addition of cadmium ion of $10^{-4}\;M$ to limit conversion of 11{\alpha}-hydroxyprogesterone into $11{\alpha}-hydroxy-allopregnane-\;3$, 20-dione.

• Land and Housing Review
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• v.4 no.1
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• pp.119-124
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• 2013

Generally, the characteristic of nanofiltration membranes were catagorized into charged membrane, sieve effect, interaction between membarnes and target solutes. This study aims to investigate the effect item of heavy metal separation with view of charge nanofiltration membranes. The experiments of nanofiltration were conducted by nanofiltration set-up with operational pressure of 0.24 MPa at $25^{\circ}C$ by using synthetic wastewater containing 0.1mg/L of Cr, Fe, Cu, Zn, As, Sn, Pb. Nanofiltration membranes rejected heavy metals much better than chloride, sulfate and TOC, of which concentration in synthetic wastewater was higher than that of heavy metals. To consider rejection characteristics of various metals by nanofiltration membranes, separation coefficient, which is the molar conductivity ratio of the metal permeation rate to the chloride ion or TOC permeation rate, was introduced. In spite of different materials and different nominal salt rejection of nanofiltration membrane used, the separation coefficients of metals were nearly the same. These phenomena were observed in the relationship between the molar conductivity and the separation coefficient for heavy metals.

• Journal of the Korean Chemical Society
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• v.12 no.2
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• pp.47-50
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• 1968

Two methods for separation of the impurities from bismuth metal have been found by the use of Dowex $1{\times}4,$ anion exchange resins. The first method is that Dowex $1{\times}4$ resins are packed into the two stage columns (height of under stage is 22cm and upper stage is 3cm, and diameter of columns are 1.5cm), and the impurities of Pb(II), Ag(I) and Cu(II) are separated by the eluent of 7.5M HCl soln, Zn(II), Fe(III) by 0.5M HCl solns, and Te(IV) in the upper stage by 2M NaOH soln. Remained Au(III) in the upper stage is determined by the ignition with resins. The 2nd method is that for the separation of all the impurities simultaneously the same resins are packed into single stage column(height is 10cm and diameter is 1.5cm), and all the impurities of Pb(II), Zn(II), Cu(II), Fe(III) and Ag(I) are eluted by the eluent of 0.5M HCl soln. Separated impurities are determined by the colorimetry.

• Korean Journal of Materials Research
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• v.5 no.2
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• pp.239-245
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• 1995

Mn-Zn ferrite thin films were deposited on $SiO_2(1000 \AA)/Si(100)$ by ion beam sputtering using a single ion source. A mosaic target consisting of a single crystal(ll0) Mn-Zn ferrite with a Fe metal strip on it was used. As-deposited films without oxygen gas flow have a wiistite structure due to oxygen deficiencies, which originated from the extra metal atoms sputtered from the metal strips during deposition. The as-deposited films with oxygen gas flow, however, have a spinel structure with (111) preferred orientation. The crystallization of thin films was maximized at the ion beam extraction voltage of 2.lkV, at which the deposited films are bombarded appropriately by the energetic secondary ions reflected from the target. As the extraction voltage increased or decreased from the optimum value, the crystallinity of thin films becomes poor owing to a weak and severe bombardment of the secondary ions, respectively. Crystallization due to the bombardment of the secondary ions was also maximized at the beam incidence angle of $55^{\circ}$. The as-deposited ferrite thin films with a spinel structure showed ferrimagnetism and had an in-plane magnetization easy axis.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.281-292
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• 2004

This pot experiment was conducted to investigate the effects of systematic variation appling of Fe, Mn, Cu, and Zn on forage performance of orchardgrass and white clover, The treatments of systematic variation were 0/100. 25/75, 50/50. 75/25, and $100/0\%$ in the Fe/Cu, Mn/Zn, and Fe+Cu/Mn+Zn trials, respectively. The treatments of Fe/Mn/Cu/Zn trial were $70\%$ in main-element and $10\%$ in other 3sub-elements. 1 . General differences had been showed in the relative contents, uptake amounts, and mutual ratios of Fe, Mn, Cu, and Zn between orchardgrass and white clover. The effects of Fe application on the all traits were generally insignificant. The Mn and Cu applications, however, showed consistent differences in the all traits. At the high relative content of Mn in the forages influenced by the Mn application, the relative contents of Fe, Cu and Zn were greatly decreased without the significant differences in common content. 2. The increase of uptake amount of each micronutrient was not positively correspond to the yield increase. In some cases, the uptake amount of micronutrient was greatly increased without the significant increase of yield. At the Mn application, the Mn uptake amount was relatively much more increased than increase of the yield. The uptake amount of each element was significantly increased by the application with Mn and Cu. However, it was not in the case of Fe and Zn. 3. The mutual ratios of micronutrients were more influenced by the applications of Mn and Cu, especially Mn, than those by the applications of Fe and Zn. In the Fe/cu trial, the ratios of Fe/Cu showed 6.0~ 10.5 in orchardgrass and 10.2~ $16.4\%$ level of difference in white clover. In the Fe+Cu/Mn+Zn trial, the ratios of Mn/Cu, Mn/Zn, and Fe/Mn were greatly influenced by the treatments. It has been also found that the poor growth of white clover was caused by the unbalanced ratios of Fe/Mn, and it tended to be enhanced by the good applications and mutual ratios of other elements.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.153-157
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• 2016

In this study, three different metal-containing ionic liquid catalysts were prepared by metal insertion and characterized by various physicochemical analytic methods. The catalytic performance of the metal containing ionic liquids in the cycloaddition of $CO_2$ with propylene oxide (PO) to produce propylene carbonate (PC) was investigated under the solvent free condition. The order of approximate rate constants ($K_{app}$) for the metal containing ionic liquid catalysts was $(MeIm)_2ZnCl_2$, > $(MeIm)_2FeCl_2$ > $(MeIm)_2CuCl_2$. These results are in accord with the experimentally obtained activity order of the different metal containing ionic liquid catalysts.

• Korean Journal of Materials Research
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• v.7 no.9
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• pp.758-762
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• 1997

52mol% Fe$_{2}$O$_{3}$, 26mol% MnO의 조성에서 calcium과 vanadium의 동시첨가에 의한 투자율의 변화원인을 살펴보았다. 초투자율은 첨가물의 농도가 커짐에 따라 감사하였으나 소결체의 밀도나 입자크기는 증가하였으므로 초투자율의 변화는 미세구조의 변화로는 설명되지 않았다. 전기비저항은 첨가물의 농도가 증가함에 따라 증가하였으며 이는 입계의 고저항층의 생성과 vanadium ion에 의한 Fe$^{2+}$이온의 산화로 설명되었다. 첨가물의 농도가 증가함에 따라, 초투자율의 제 2차 최대치가 나타나지 않는 것과 초투자율이 감소하는 것으로부터, 결정자기이방성 상수의 값은 음으로 커짐을 알 수 있었다. 투자육의 온도의존성과 비저항의 변화로부터, 첨가물의 농도에 따른 상온 초투자율의 감소는 Fe$^{2+}$ 이온 농도의 감소에 따른 결정자기이방성 상수의 증가에 의한 효과와 입계에 유리질이 생겨 자벽이 쉽게 이동하지 못하는 효과 때문인 것으로 판단되었다.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.77-84
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• 2007

A fungus, Aspergillus sp. PS-104, with the high phosphate-solubilizing activities was isolated from Korean upland soil and formulated into a solid powder type with various additives. For the long-time preservation of conidia, some additives (Tween 80, SDS, Triton X-100, glucose, glycerol, corn oil, bio-ceramic, PEG 200, $Cu^{++}$, $Mo^{+++}$, $Fe^{++}$, $Ca^{++}$ and $Zn^{++}$) were supplemented in the rice-cooked hard medium with various concentrations (0, 0.001, 0.01, 0.1, 1.0 and 5.0%). In case of surfactants. the highest relative viability of the Aspergillus sp. PS-104 conidia was recorded nearly to 80% by the addition of 0.01 to 0.1% Tween 80, while 50% in control. The number of conidia were found to be about 100 times higher when treated at 0.01 to 0.1% Tween 80 as compared to control. Relative viability of the conidia was decreased in order of Tween 80 $\geq$ SDS > Triton X-100 during the storage at $25^{\circ}C$. As regards the organic additives, the relative viability of Aspergillus sp. PS-104 conidia was also recorded nearly to 80% by the addition of 1.0% bio-ceramic, and 5.0% glucose and sucrose during the storage at $25^{\circ}C$. In case of metal ions, the relative viability of Aspergillus sp. PS-104 conidia was decreased in order of $Cu^{2+}>Ca^{2+}>Mo^{3+}>Zn^{2+}>Fe^{2+}$ during the storage at $25^{\circ}C$.