• Journal of the Korean Applied Science and Technology
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• v.25 no.1
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• pp.41-47
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• 2008

This study was conducted to made a grid alloy (Pb-Ca-Sn-Al) which has a temporary composition ratio in order to improve the efficiency of lead acid batteries. The positive activity material made a 3BS(tri-basic lead sulfate; $3PbO{\cdot}PbSO_4{\cdot}H_2O$) by a low temperature curing and it evaluates the plate efficiency through the life cycle testing. The initial current capacity of low temperature curing plate was excellent but the life cycle was not good (S1). As for the S2 plate, however, the initial current capacity and the life cycle were superior.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.27-33
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• 2007

It is very important in the view point of resource recycling to recover valuable metals such as copper and tin from waste electric and electronic scrap. The waste electric and electronic scrap contains significant amounts of copper, tin, and so on. In this study, a new process for extracting copper and tin contained in the waste electric and electronic scrap using waste copper slag which is generated from the melting furnace of copper smelter was presented. Advantage of the proposed process is to reuse waste copper slag instead of new fluxes as slag formatives. In each experiment, the waste electric and electronic scrap and waste copper slag were melted inputting suitable amount of CaO as an additional flux. Up to 95% of copper and 85% of tin in the raw material were extracted in a Cu-Fe-Sn alloy phase.

• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.175-181
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• 1994

A bacterial strain producing highly viscous polysaccharide(A29 POL) was isolated from soil and identified sa Bacillus sp. A29. The cultural conditions of the Bacillus sp. A29 for the polysaccharide prouction were dextrin 12%, soytone 0.2%, SnCl$_{2}$ $\cdot $2H$_{2}$O 0.02%, Na$_{2}$HPO$_{4}$ $\CDOT $12H$_{2}$O 0.36%, L-alanine 0.01%, initial pH6.8, and 30$\circ $C at pH 3 FOR 4 days. Final viscosity of the culture broth was 65, 000 cp and then the amount of produced polysaccharide was 8.3 g/l. A29 POL was composed of glucose and xylose. A29 POL showed high viscosity at low concentration(0.1%) and in the presence of the salts such as NaCl or CaCl$_{2}$. A29 POL showed high viscosity acid condition and at alkali condition and high pseudoplasticity in the presence of a NaCl or CaCl$_{2}$. It was shown that the viscosity at high temperature(80$\circ $C) was decreased but it was recovered at low temperature (20$\circ $C. A29 POL was able to from film and gel in the presence of MgSO$_{4}$ $\CDOT $7H$_{2}$O, Na$_{2}$CO$_{3}$ \CDOT $H$_{2}$O, MnSO$_{4}$ $\CDOT $ 7H$_{2}$O. A29 POL had anionic charge.

• Polymer(Korea)
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• v.25 no.1
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• pp.98-107
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• 2001

Dielectric properties and shape memory characteristics of SBS composites filled with carbon black as conductive filler and (Ba,Ca)$(Sn,Ti)O_3$ or $SrTiO_3$ as dielectrics were investigated for the development of phantom model. SBS/carbon black composite showed an increment of complex dielectric constant with increasing the content of carbon black and the frequency dependence that the dielectric constant decreases with the frequency. The complex dielectric constant and the conductivity of SBS/carbon black/dielectrics composites increased with the increase of dielectrics and the characteristics of the frequency dependence also occurred by the effect of carbon black. Phantom materials with the dielectric properties and the conductivity corresponding to human tissues for the measurement of specific absorption rate(SAR) within the frequency range of current mobile phones(775MHz~2GHz) could be developed by adjusting the composition ratios of carbon black, dielectrics and SBS and by controlling the characteristic of frequency dependence of composite. From thermomechanical cycling test good shape recoverability could be obtained in SBS composite even though the residual strain was increased by the effect of filler.

• Journal of the Korean Ceramic Society
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• v.38 no.7
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• pp.597-601
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• 2001

The effect of CuO, $B_2$ $O_3$, $V_2$ $O_{5}$ and CuO-B $i_2$ $O_3$additives on microwave dielectric properties of (P $b_{0.45}$C $a_{0.55}$) [(F $e_{0.5}$N $b_{0.5}$)$_{0.9}$S $n_{0.1}$] $O_3$(PCFNS) were investigated. The PCFNS ceramics were sintered at 11$65^{\circ}C$. To decrease the sintering temperature for using as a low-temperature co-firing ceramics (LTCC), CuO, $B_2$ $O_3$, $V_2$ $O_{5}$ and CuO-B $i_2$ $O_3$were added to the PCFNS. As the content of CuO increased, the sintered density and dielectric constant increased and the temperature coefficient of resonance frequency ($\tau$$_{f}$) shifted to the positive value. When the CuO-B $i_2$ $O_3$were added, dielectric properties were $\varepsilon$$_{r}$ of 83, Q. $f_{0}$ of 6085 GHz, and $\tau$$_{f}$ of 8ppm/$^{\circ}C$ at a sintering temperature of 100$0^{\circ}C$. The relationship between the microstructure and properties of ceramics was studied by X-ray diffraction and scanning electron microscopy.icroscopy.y.icroscopy.y.

• Economic and Environmental Geology
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• v.42 no.3
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• pp.177-193
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• 2009

The Samgwang deposit consists of eight massive mesothermal quartz veins that filled NE and NW-striking fractures along fault zones in Precambrian granitic gneiss of the Gyeonggi massif. The mineralogy and paragenesis of the veins allow two separate discrete mineralization episodes(stage I=quartz and calcite stage, stage II-calcite stage) to be recognized, temporally separated by a major faulting event. The ore minerals are contained within quartz and calcite associated with fracturing and healing of veins that occurred during both mineralization episodes. The hydrothermal alteration of stage I is sericitization, chloritization, carbonitization, pyritization, silicification and argillization. Sericitic zone occurs near and at quartz vein and include mainly sericite, quartz, and minor illite, carbonates and chlorite. Chloritic zone occurs far from quartz vein and is composed of mainly chlorite, quartz and minor sericite, carbonates and epidote. Fe/(Fe+Mg) ratios of sericite and chlorite range 0.45 to 0.50(0.48$\pm$0.02) and 0.74 to 0.81(0.77$\pm$0.03), and belong to muscovite-petzite series and brunsvigite, respectiveIy. Calculated $Al_{IV}$-FE/(FE+Mg) diagrams of sericite and chlorite suggest that this can be a reliable indicator of alteration temperature in Au-Ag deposits. Calculated activities of chlorite end member are $a3(Fe_5Al_2Si_3O_{10}(OH)_6$=0.0275${\sim}$0.0413, $a2(Mg_5Al_2Si_3O_{10}(OH)_6$=1.18E-10${\sim}$7.79E-7, $a1(Mg_6Si_4O_{10}(OH)_6$=4.92E-10${\sim}$9.29E-7. It suggest that chlorite from the Samgwang deposit is iron-rich chlorite formed due to decreasing temperature from high temperature(T>450$^{\circ}C$). Calculated ${\alpha}Na^+$, ${\alpha}K^+$, ${\alpha}Ca^{2+}$, ${\alpha}Mg^{2+}$ and pH values during wallrock alteration are 0.0476($400^{\circ}C$), 0.0863($350^{\circ}C$), 0.0154($400^{\circ}C$), 0.0231($350^{\circ}C$), 2.42E-11($400^{\circ}C$), 7.07E-10($350^{\circ}C$), 1.59E-12($400^{\circ}C$), 1.77E-11($350^{\circ}C$), 5.4${\sim}$6.4($400^{\circ}C$), 5.3${\sim}$5.7($350^{\circ}C$)respectively. Gain elements(enrichment elements) during wallrock alteration are $TiO_2$, $Fe_2O_3(T)$,CaO, MnO, MgO, As, Ag, Cu, Zn, Ni, Co, W, V, Br, Cs, Rb, Sc, Bi, Nb, Sb, Se, Sn and Lu. Elements(Ag, As, Zn, Sc, Sb, Rb, S, $CO_2$) represents a potential tools for exploration in mesothermal and epithermal gold-silver deposits.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.1-5
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• 1998

A spectrophotometric method was developed for the acidic solution stripped after an extraction of 0.5 to 2.5 ppm of Lead(II) from 50 mL of $Na_2S_2O_3$ solution into chloroform as the ion-pairs formed between their thiosulfate complexes and alkylamine, Aliquat336. Pb(II) in the stripped solution forms an complex with DDTC in pH 7.3 buffer solution, and was developed in yellow by copper replacement. The ydlow-colored solution have the maximum absorbance at 435 nm in the measurement of absorbance by UV-Visible spectrophotometer. The interference ions such as Fe(III), Hg (II), Al(III), Co, Cu, Ni, Zn, Ca, Sn, have great effects on the extraction, but they were overcomed by the usage of adequate masking agents before an extraction. At last, a good result was obtained in applying this method to synthetic water.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.615-620
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• 2009

The present research was performed to determine the optimal firing condition and holding time for malayaite crystal, which is responsible for the stable pink-red coloration in glaze at high temperatures, using Cr$Cl_3$ as chromophore for the synthesis of $Cr_2O_3-SnO_2-CaO-SiO_2$ system pigments. The malayaite crystal was influenced by the raw materials used for synthesis, firing temperature, and holding time. Thus there are differences in the crystal phase and in the coloration according to the condition of synthesis. When Cr$Cl_3$ was used as chromophore, the pigment could be synthesized at lower temperatures, because Cr$Cl_3$ melts at $1500{^{\circ}C}$, which is much lower than the temperature at which $Cr_2O_3$ melts (higher than $2435{^{\circ}C}$). And the employed Cr ion showed a change in oxidation state. When a mineralizer was used to improve the employment of malayaite and the Cr ion, and the low temperature was maintained at which the malayaite crystal is produced, the production of malayaite crystal was promoted and the employment of chromophore was also promoted in the oxidation state of Cr (IV). The results of the experiment showed that the optimal firing condition was 18 h of holding time at $800{^{\circ}C}$, using Cr$Cl_3$ as chromophore, followed by 2 h at the raised temperature of $1150{^{\circ}C}$. The change in coloration of the Cr (IV) employed by malayaite showed a very rich color of red. Thus it was possible to effectively synthesize sphene-pink pigments with more red tint at a low temperature.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.694-702
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• 2014

The micron-sized ITO(indium tin oxide) particles were prepared by spray pyrolysis from aqueous precursor solutions for indium, and tin and organic additives solution. Organic additives solution with citric acid(CA) and ethylene glycol(EG) were added to aqueous precursor solution for Indium and Tin. The obtained ITO particles prepared by spray pyrolysis from the aqueous solution without organic additives solution had spherical and filled morphologies whereas the obtained ITO particles with organic additives solution had more hollow and porous morphologies with increasing mole of organic additives. The micron-sized ITO particle with organic additives was changed fully to nano-sized ITO particle whereas the micron-sized ITO particle without organic additives was not changed fully to nano-sized ITO particle after post-treatment at $700^{\circ}C$ for 2 hours and wet-ball milling for 24 hours. The size of primary ITO particle by Debye-Scherrer formula and surface resistance of ITO pellet were measured.

• Economic and Environmental Geology
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• v.27 no.3
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• pp.237-246
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• 1994

Tin mineralizations in South Korea have been found only in the Ulchin and Sangdong areas. They appear to be in close spatial association with the Wangpiri granitoid in the UlChin area, and the Nonggeori and Naedeogri granites in the Sangdong area. However, previous works have revealed that there are considerable differences in geological setting, mineralogical and geochemical compositions among these granitoids concerned. The roles of discriminant and multiple regression analysis have been examed to establish geochemical differences among the tin-granitoids and to identify elements relating to tin mineralizations. The data set used in this study consists of 60 observations with 29 elements which are cited from pre-existing publications. A stepwise discriminant analysis determined the group of variables that differentiate between samples from four training sets; Buncheon, Wangpiri, Nonggeori and Naedeogri granitoids. These granitoids were most effectively discriminated on the basis of major elements FeO, CaO and $P_2O_5$ and also by the trace elements Rb and Zr. Results of the multiple regression analysis shows that the level of Sn in granitoids depends positively on ones of MnO, Rb and FeO and negatively $P_2O_5$. Graphical representation of discriminant scores on sampling locations greatly aid recognition of differences in the geochemical characteristics in terms of spatial distribution of granitoids examed. The application of the discriminant analysis provides a potential means of identifying and comparing geochemical characteristics.