• Economic and Environmental Geology
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• v.30 no.4
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• pp.279-289
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• 1997

Dark to pale green-colored, Cr-bearing sericites from hydrothermal alteration zone of the Narim gold deposit were investigated mineralogically and geochemically. The alteration zone is composed mineralogically of quartz, carbonate minerals and green sericite with minor amounts of chlorite, barite and sulfide minerals (pyrite, sphalerite, galena). The zone is enriched in As (967 to 1520 ppm), Cu (31 to 289 ppm), Ni (1027 to 1205 ppm), Pb (0.20 to 1.24 wt.%) and Zn (1.03 to 1.07 wt. %) compared with fresh rocks such as granitic gneiss, porphyritic biotite granite and basic dyke. The Cr, probably the chromophore element, is highly enriched in the alteration zone (1140 to 1500 ppm), host granitic gneiss (1200 ppm) and porphyritic biotite granite (1200 ppm). Occurrence and grain size of sericite are diverse, but most of the Cr-bearing sericites (150 to $200{\mu}m$ long and 20 to $30{\mu}m$ wide) occur along the boundaries between ore veins and host rocks (especially basic dyke and granitic gneiss). X-ray diffraction data of the sericite show its monoclinic form with unit-cell parameters of $a=5.202{\AA}$, $b=8.994{\AA}$, $c=20.103{\AA}$, ${\beta}=95.746^{\circ}$ and $V=935.83{\AA}^3$, which are similar with the normal 2M1-type muscovite. Representative chemical formula of the sericite is ($K_{1.54}Ca_{0.03}Na_{0.01}$)($Al_{3.42}Mg_{0.38}Cr_{0.14}Fe_{0.06}V_{0.02}$)($Si_{6.69}Al_{1.31}$)$O_{20}(OH)_4$. The Cr content increases with decrease of the octahedral Al content, and ranges from 0.36 to 2.58 wt.%. DTA and TG curves of the sericite show endothermic peaks at $342^{\circ}$ to $510^{\circ}$, $716^{\circ}$ to $853^{\circ}$ and $1021^{\circ}C$, which are due to the expulsion of hydroxyl group. The total weight loss by heating is measured to be about 8.8 wt. %, especially at $730^{\circ}C$. Infrared absorption experiments of the sericite show broad absorption band due to the O-H bond stretching vibration near the $3625cm^{-1}$, coupled with the 825 and $750cm^{-1}$ doublet. The vibration bands related with the H-O-Al and Si-O-Al bonds occur at $1030cm^{-1}$ and 500 to $700cm^{-1}$, respectively. Based on paragonite content of the sericite, the formation temperature of the Narim gold deposit is calculated to be $220{\pm}10^{\circ}C$.

• Food Engineering Progress
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• v.14 no.1
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• pp.49-53
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• 2010

Surface plasmon resonance (SPR) which is utilized in thin film refractometry-based sensors has been concerned on measurement of physical, chemical and biological quantities because of its high sensitivity and label-free feature. In this paper, an application of SPR to detection of alcohol content in wine and liquor was investigated. The result showed that SPR sensor had high potential to evaluate alcohol content. Nevertheless, food industry may need SPR sensor with higher sensitivity. Herein, we introduced a nano-technique into fabrication of SPR chip to enhance SPR sensitivity. Using Langmuir-Blodgett (LB) method, gold film with nano-structured surface was devised. In order to make a new SPR chip, firstly, a single layer of nano-scaled silica particles adhered to plain surface of gold film. Thereafter, gold was deposited on the template by an e-beam evaporator. Finally, the nano-structured surface with basin-like shape was obtained after removing the silica particles by sonication. In this study, two types of silica particles, or 130 nm and 300 nm, were used as template beads and sensitivity of the new SPR chip was tested with ethanol solution, respectively. Applying the new developed SPR sensor to a model food of alcoholic beverage, the sensitivity showed improvement of 95% over the conventional one.

• Journal of the Mineralogical Society of Korea
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• v.6 no.2
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• pp.94-104
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• 1993

The compositional variation of electrums from gold-silver and antimony deposits in the Dunjeon Baegjeon mining area, range from 22.6 to 69.5 atom% of Ag. Ag contents in electrums vary with paragenetic sequences and associated minerals. Ag contents increase from core to margin in a single grain. Compositional range of electrums from the North ore deposits of the Dunjeon gold mine are from 22.6 to 29.5 atom% of Ag. Electrums contain Cu(0.40 to 0.55 atom%) and Bi(0.35 to 0.67 atom%). Composition of electrums from the South ore deposits of the Dunjeon gold mine vasies from 33.6 to 69.5 atom% of Ag. Cu and As contents in electrums range from 0.20 to 1.92 and from 0.70 to 1.90 atom%, respectively. As the content of Ag in electrums increase, the contents of Bi and As in electrums increase but that of Cu decrease. Electrums of the Baegjeon gold deposits contain 35.6 to 63.5 atom% of Ag, suggesting that Au contents in electrums associated with base metal sulfied be higher than those associate with Ag-minerals. Ag/Au rations in electrums increase with decreasing temperature, salinity and $fs_2$ of the mineralizing solution.

• Journal of Conservation Science
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• v.33 no.2
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• pp.107-120
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• 2017

This research involves a gilding experiment using plum acid that has previously been reported to restore Geumdongsamjonpanbul excavated from Wolji, Gyeongju. Chromaticity analysis revealed that the yellowness of the samples was high, and the samples treated with acid for more than 10 minutes showed high brightness. SEM studies revealed that the sample subjected to amalgam application and immediate heating was rarely gilded with gold. When the amalgam application time was longer than 36 h, the gold layer observed was uneven. Therefore, the optimum amalgam application time was 12-24 h. EDS analysis showed that mercury content was ~5 wt.% for samples with an acid treatment time of 20 min, lower than that in other samples. Gold gilding was successful for the sample with amalgam application time of 24 h and acid treatment time of 20 min. This sample showed the high-resolution XPS peak corresponding to Au and retains a little Hg compared with the other samples. In other words, experimental and analytical results using plum acid showed that gilding was successful when acid treatment time was 20 min and amalgam application time was 24 h. Based on these results, Geumdongsamjonpanbul excavated from Wolji, Gyeongju can be restored.

• Journal of Life Science
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• v.19 no.1
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• pp.152-155
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• 2009

The old-gold-crimson ($og^c$) fruit color mutation produces deep red tomato fruit with high lycopene content. age is a null mutation allele of lycopene-${\beta}$-cyclase (Crt-b) gene (B locus) that converts lycopene to ${\beta}$-carotene in the cartenoid biosynthesis pathway in tomato. Breeding of high lycopene tomato cultivars can be accelerated by marker-assisted selection (MAS) for introgression of $og^c$ allele by using a gene-based DNA marker. In order to develop a marker, single nucleotide deletion of adenine(A) with. in a poly-A repeat that has been known to be responsible for frame-shift mutation of $og^c$ was confirmed by resequencing mutant allele and wild-type allele at B locus of several tomato lines. For allele discrimination and detection of $og^c$, derived CAPS (dCAPS) approach was used by designing a primer that artificially introduced restriction enzyme recognition site of Hin fI in PCR products from $og^c$ allele. This dCAPS marker is co-dominant gene-based PCR marker that can be efficiently used for MAS breeding program aiming the development of high lycopene tomato.

• Economic and Environmental Geology
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• v.23 no.1
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• pp.25-33
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• 1990

Gold-silver deposits of Deogheun and Beopjeon mines are composed of veins emplaced in Jurassic granite batholith. Based on ore structure and ore mineralogy, four distinct stages of mineral deposition are recognized in these ore deposits. Gold and silver minerals in Deogheun and Beopjeon-A ore deposits are precipitated in stage III and stage II, respectively. Mineral constituents of ores from these deposits are pyrite, sphalerite, arsenopyrite, pyrrhotite, chalcopyrite, galena, tetrahedrite, electrum, quartz and rhodochrosite. Cubanite, argentite and pyrargyrite occur only in Deogheun ore deposits. Ag content of electrum range from 42 to 66 atomic % in both ore deposits. Filling temperature of fluid inclusion from both ore deposits are as follows; stage I, $211-289^{\circ}$ ; stage II, $205-290^{\circ}$ ; stage III, $190-260^{\circ}$ ; stage IV, $136-222^{\circ}$ in Deogheun ore deposits. In Beopjeon-A ore deposits, stage I, $255-305^{\circ}$ ; stage II, $135-222^{\circ}$ ; stage III, $148-256^{\circ}$ ; stage IV, $103-134^{\circ}$. Salinities of fluid inclusions range from 1.6-8.5 wt. % equivalent NaCl in both ore deposits. Sulfur fugacities through stage II and III in Deogheun ore deposits inferred from data of mineral assemblage and fluid inclusion range from $10^{-11.0}-10^{-16.1}$1bars. Fluid pressure estimated from fluid inclusions which reveal boiling evidence range from 30-190 bars during mineralization in Deogheun ore deposits.

• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.228-233
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• 2010

Recently, nanoparticles of gold and silver has been applied to various fields due to antimicrobial property. This study added Ag and Au nanoparticles in HEMA (2-hydroxyethylmethacrylate), NVP (N-vinyl pyrrolidone) and MMA (methylmethacrylate) and copolymerized the solution by heating at $70^{\circ}C$ for 40 minutes, $80^{\circ}C$ for 40 minutes, and finally, $100^{\circ}C$ for 40 minutes. Using the polymer produced through the copolymerization process, and measured the physical characteristics which showed water content of 28.43% ~ 35.27%, refractive index of 1.429 ~ 1.440, visible transmittance of 79.2% ~ 86.5% and tensile strength of 0.125 kgf ~ 0.201 kgf. We judged that we made the copolymer with antimicrobial and physical properties which is suitable for conventional contact lens.

• Resources Recycling
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• v.22 no.4
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• pp.33-37
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• 2013

A study on the removal of arsenic from gold concentrate was conducted using thermal decomposition method at $700^{\circ}C$ as a function of reaction time. In addition, the arsenic removed from the concentrate was also collected in the bag-filter as a form of AsS. The content of arsenic in the concentrate was dramatically decreased from 12.62 wt/% to 1.40 wt.% for 1 hour and even lower than 1 wt.% after two hours. The removal efficiency of arsenic was finally achieved to be about 95% after 2 hours at a given temperature.

• Food Science and Preservation
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• v.30 no.2
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• pp.247-261
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• 2023

Kimchi cabbage is widely consumed in Korea, with the popularity of this pickled vegetable dish growing internationally due to its health benefits. In this study, the physical (size, color), functional (antioxidant activity, total polyphenol, and flavonoid content), and nutritional (water- and fat-soluble vitamins) characteristics of two new kimchi cabbage varieties, namely red and gold kimchi cabbages (RKC and GKC, respectively), were analyzed and compared with those of the common kimchi cabbage (CKC). There were no significant differences in the thickness or length of the three kimchi cabbages, although RKC had the narrowest outer leaves among the three varieties (11.94 cm). Regarding chromaticity, yellowness was highest in GKC (29.86), whereas redness was highest in RKC (9.31). Furthermore, RKC had the highest recorded vitamin B₆ and B₉ (1,288.5 ㎍/100 g and 776.7 ㎍ dietary folate equivalent/100 g, respectively). On the other hand, the fat-soluble vitamins vitamin A (β-carotene) and K (Phylloquinone) were both highest in GKC (907.1 ㎍/100 g and 712.2 ㎍/100 g, respectively). Generally, all kimchi cabbage samples contained high levels of vitamin E (1.8-4.9 mg α-tocopherol equivalent/100 g). RKC attained the highest antioxidant activity and total polyphenol and total flavonoid contents among the three kimchi cabbages. These results show that gold and red kimchi cabbage can be used as raw materials in the food-processing industry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.24-24
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• 2009

ENIG(Electroless Nickel Immersion Gold) is the surface treatment method that is used most widely at fine pitch's SMT and BGA packaging process. In this paper, we have studied the effect of P content variation during ENIG process on those phenomena related to the solder joint. The effect of P content was discussed using the results obtained from FE-SEM, EPMA, EDS and FIB. Finally, it was concluded that the more P-content in Ni layer, the thicker P-rich layer.