• BMB Reports
• /
• v.38 no.4
• /
• pp.399-406
• /
• 2005

A sensitive method for detection of Hepatitis A virus (HAV) by utilizing gold-DNA probe on an array was developed. Amino- modified oligodeoxynucleotides at the 5' position were arrayed on an activated glass surface to function as capture probes. Sandwich hybridization occurred among capture probes, the HAV amplicon, and gold nanoparticle-supported oligonucleotide probes. After a silver enhancement step, signals were detected by a standard flatbed scanner or just by naked eyes. As little as 100 fM of HAV amplicon could be detected on the array. Therefore, the array technology is an alternative to be applied in detection of HAV due to its low-cost and high-sensitivity.

• Economic and Environmental Geology
• /
• v.46 no.1
• /
• pp.21-28
• /
• 2013

In order to optimize gold leaching from refractory sulfide concentrate, a HCl-NaClO-$FeCl_3$ solution with varying attributes was applied to the roasted concentrate from Uil mine. The gold from Uil mine occurs in the form of invisible gold that is difficult to leach. The results of the gold leaching experiments showed that the best gold leaching parameters were $550^{\circ}C$ of roasting temperature, 2.0 M of concentration, 1.0% of pulp density, and $70^{\circ}C$ of leaching temperature. It is confirmed that the HCl-NaClO-$FeCl_3$ solution was an environmentally friendly method to leach gold and silver from the refractory sulfide concentrate as an alternative lixiviant to cyanide.

• Economic and Environmental Geology
• /
• v.17 no.2
• /
• pp.91-100
• /
• 1984

The Gwangyang gold deposits geologically consist of granitic gneiss, metatectic gneiss and porphyroblastic gneiss which correspond to Jirisan gneiss complex. The formations of Gyeongsang system lies unconformably on these gneisses and are intruded by diorite, porphyritic andesite and Bulgugsa granites. Goheung districts are composed of quartz schist, andesitic rock, tuff and granite. The Gwangyang gold deposits are gold bearing fissure filling veins. The vein thickness varies from 15cm to 40cm and they consist of 7-10 layers in parallel. The Goheung copper deposits are sulphide bearing quartz veln which filled the fracture in andesitic rock and biotite granite. The contact zone of these rocks is partially altered. The mineral paragenesis of the Gwangyang and Goheung districts is pyrite, arsenopyrite, pyrrhotite, chalcopyrite, sphalerite, galena, sericite, quartz and calcite. The variation trends of FMA and A'KF triangular diagrams and the differentiation index (norm, Q + Or + Ab) versus oxides diagrams is similar to the Gyeonsang basin igneous rocks. From the trace element analysis of 10 samples of country rocks, wall rocks and veins, the distribution of copper and lead contents display a correlative distribution pattern in relation to gold and silver. Homogenization temperature of fluid inclusions range from $200^{\circ}C$ to $270^{\circ}C$ in quartz from the Gwangyang gold vein and the size of fluid inclusion range from 0.01mm to 0.04mm. The fluid inclusions are mainly one or two phase and the filling degree of the inclusions varies from 85 to 95.

• Journal of Conservation Science
• /
• v.1 no.1 s.1
• /
• pp.60-79
• /
• 1992

In relation to the scientific conservation treatment of ancient gilt bronze, the gold film coated on the bronze excavated from Hwangnam Great Tomb of Old Silla Kingdom(A. D. 5C) was studied in the view of coating technology and metallurgy of bronze. The uniform and dense gold film containing $2.44\sim12.40%$ of Hg with the thickness of $5.99\sim12.97{\mu}m$ was found to be coated on the bronze objects by amalgam coating method. On silver objects, the film with the thickness of $19.96{\mu}m$ was coated also continously and uniformly with gold by the same method. The bronze objects was fabricated by forging technique and contained almost $4.7\sim11.5%$ of Pb. Its microstructure was $\alpha-phase$ solid solution including Pb segregation in the matrix. The amount of $0.4\sim2.0%$ Zn was added in the bronze for the purpose of easy fabricating of Cu alloy. Based on the data studied, the gold film on bronze sample was reproduced by amalgam coating method and compared with the ancient gold film.

• Economic and Environmental Geology
• /
• v.31 no.5
• /
• pp.389-398
• /
• 1998

The Au-Ag deposit of the Oknam mine occurs as gold-silver-bearing rhodochrosite veins in biotite schist and phyllite of the Precambriam Yulri Group. Five stages of ore deposition are recognized, each showing a definite mineral assemblage. General mineral parageneses in veins (stage III) associated with gold and silver vary inwardly from the vein margin: arsenopyrite + pyrite $\Rightarrow$ sphalerite+chalcopyrite+galena+gold $\Rightarrow$ ga1ena+Ag-bearing minerals. Fluid inclusion data indicate that temperature and salinity of ore fluids overally decreased with time: $345^{\circ}{\sim}240^{\circ}C$ and 3.4~7.8 wt. % NaCl equiv during stage I (quartz vein mineralization), $313^{\circ}{\sim}207^{\circ}C$ and 2.3~8.7 wt.% NaCl equiv during manganese-bearing carbonate stages (II and III), and $328^{\circ}{\sim}213^{\circ}C$ and 3.6-5.4 wt.% NaCl equiv during stage IV (quartz vein mineralization). The ore fluids probably evolved through repeated pulses of boiling and later mixing with cooler and more dilute meteoric waters. Fluid inclusion data and geologic arguments indicate that pressures during the mineralization were in the range of 90 to 340 bars. Gold occurs as silver-rich electrums (21 to 29 atom. % Au) and was deposited at temperatures between $300^{\circ}$ and $240^{\circ}C$. Thermochemical calculations suggest that gold was deposited as a combined result of increase in pH and decreases in temperature, $fs_2$ and $fo_2$.

• Journal of Technologic Dentistry
• /
• v.30 no.2
• /
• pp.31-37
• /
• 2008

A variety of the porcelain fused to gold(PFG) have been developed to which porcelain can be fused. PFG alloys developed for this purposed have a high melting point and do not discolor when combined with porcelain. The design of the compositions of PFG is very important to esthetic restorative materials applying to porcelain. The purpose of this study is on the change of physical and mechanical characteristics in PFG 18K alloy by the small additional elements. Principal results are as follows. The high Au alloy containing 18Karat gold contents is respectively Au(75%), Pd(10%), Pt(4%), Ag(4%), In(2%), Sn(2%), Cu(2%), Ti(1%). These alloys are composed mainly of gold, platinum, silver and palladium with a few percent of the additional elements. By the addition of small amounts of elements such as In, Sn, Ti, the fine grain castings are produced in gold alloy and the small addition of platinum is very effective in increasing of hardness and strength. These gold alloys are representative of the changes to be expected as a result of heat treatment. These changes in strength and hardness values are sufficient to demonstrate a significant difference in performance between a as-casted and a heat-treated. These alloys have mechanical properties characteristics of Type and Type gold alloys. These alloys are useful to porcelain-metal restorations and dental laboratory. Also the porcelain fused to metal(PFM) alloys containing gold are commonly use for dental purposes in dental laboratory.

• Conservation Science in Museum
• /
• v.16
• /
• pp.46-55
• /
• 2015

This study examines the ratio of alloy components of six gold crowns discovered in six Silla tombs; Gyo-dong, the north tomb of Hwangnamdaechong, Geumgwanchong, Cheonmachong, Geumnyeongchong and Seobongchong. Concretely, the study looks at whether and how crowns from these various tombs differ in terms of the ratio of alloy components. The analysis of the six Silla crowns found that all of them were made of gold and silver alloy. When comparing the ratio of alloy components in crowns and type of crowns, the Gyo-dong crown which is the oldest of them showed the highest content of gold. Crowns from Hwangnamdaechong and Geumgwanchong in the middle to late 5th century, showed a similar content of gold. Gold content of crowns from the late 5th century to early 6th century tombs decreased in order Cheonmachong, Geumnyeongchong and Seobongchong, thus it confirmed that the older the tomb, the higher its gold content.

• Journal of radiological science and technology
• /
• v.6 no.1
• /
• pp.43-67
• /
• 1983

In order to increase the sensitivity of the photographic emulsion, one of the chemical sensitizers hydroxymethane sulfonic acid sodium salt(HMS) was applied through the chemical ripening process and following four types of emulsion were prepared. Their grain sizes were determined through the electron microscope. The ranges of average grain sizes were $0.05-0.40{\mu}m$ for silver chlorobromide emulsion of low sensitivity $0.10-0.45{\mu}m$ for the silver chlorobromide emulsion of medium sensitivity, $0.60-1.05{\mu}m$ for the silver iodobromide emulsion of high sensitivity, and $0.90-1.55{\mu}m$ for the ammonical silver iodobromide emulsion of high sensitivity. Through the reduction sensitization with HMS, they showed significant sensitivity enhancement by the increment of HMS concentration above pH 5.5 and pBr 3.0. Required sensitivity was obtained above pH 6.2 and pBr 3.3 when sulfur and gold sensitization were applied. Fog formed along the reduction sensitization was successfully prevented by the addition of 5.5-dimethylhydantion.

• Journal of the Korean Chemical Society
• /
• v.17 no.2
• /
• pp.126-129
• /
• 1973

An amperometric method has been developed for the titration of silver with 2,5-dimercapto-1,3,4,-thiadiazole in ammonical solution (1N) using rotating platinum electrode as an indicator electrode and the mercury-mercury (II) iodide as reference electrode. Direct titration of milligram amount of silver (0.05-1.0mg) is possible in the presence of a number of foreign ions in ammonical solution containing ethylenediaminetetraacetic acid as masking agent under atmosphere. The interfering elements are gold and platinum. The milligram amount of silver can be determined by the proposed method within an error ${\pm}3{\%}$.

• Proceedings of the KSEEG Conference
• /
• 2005.04a
• /
• pp.82-85
• /
• 2005