• The Journal of Korean Academy of Prosthodontics
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• v.38 no.3
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• pp.328-335
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• 2000

Statement of the problem. Recently an innovative method of fabricating indirect restorations by gold electroforming has been developed. But the bond quality and strength of the gold coping to the porcelain is uncertain. Purpose of study. The purpose of this study is to analyze and evaluate the electroformed gold surface for mechanical bonding between the gold and the ceramic veneering. Methods/material. Electroformed disks were made using electroforming technique. And the surface of the electroformed coping was analyzed after sandblasting, heat-treatment, bonding agent application, opaque porcelain firing with scanning electron microscopy and energy dispersive x-ray analysis. Results. In the analysis with SEM, Sandblasting made the sharp edges and undercuts on the electroformed surface, and after bonding agent application, net-like structure were created on the electroformed surface. In the energy dispersive x-ray analysis it is confirmed that electroformed surface contains some impurities. Conclusion. With the use of sandblasting and bonding agent, electroformed surface seems to be enough to bond with veneering porcelain.

• Journal of Conservation Science
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• v.31 no.1
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• pp.21-27
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• 2015

The Phoenix-shaped Glass Ewer, which is No. 193 National Treasure, was seriously damaged by a unique form of green glass pieces when excavated among a number of burial accessories of Hwangnamdaechong known to have been formed in the 5th century. While it has long been exhibited at the National Museum of Korea since its treatment for conservation treatment at conservation science laboratory in 1984, the existing adhesive materials seriously deteriorated for the 30 years, and the condition was quite unstable. The epoxy resin used as a restorative materials turned yellowing due to the light and heat so much that it was no longer able to exhibit it in a stable and effective manner. As a result, a re-treatment for conservation was conducted lately. This study focuses on the three pieces of Gold wires used to carefully wrap up the handle of the Phoenix-shaped Glass Ewer broken into three pieces, which has not been studied so far. As for the analysis method for Gold wires, SEM-EDS and Stereo Microscope were used for nondestructive analysis. First of all, the result of the SEM-EDS analysis shows that the composition was Au 91.9 wt.%-Au 92.8 w.t% and Ag 5.9 wt.%-Ag 6.5 wt.%, which indicates that it was an alloy made of Au and Ag. The production technique of Gold wires was also observed by means of optical microscopes. In general, Gold wires were manufactured by a drawing process in which a lump of gold was beaten or pulled out of a hole or by a process of twisting a gold plate. However, Gold wires separated from the handle of the Phoenix-shaped Glass Ewer did not involve any trace of twisting on the surface. Rather, fine vertical stripes were observed with the sections filled up. Hence, it is thought that this Ewer went through a drawing process and then was mended. As a result, no certain relation with the golden mending material used for the Phoenix-shaped Glass Ewer was verified. The findings above indicate that most of the existing researches on Gold wires recognized them, not as separate remains, but merely as a component of other golden remains. Thus, there has been little systematic study on the manufacturing techniques of Gold wires. The future study on Gold wires may verify the correlation between the Gold wires used to fix the handle of the Phoenix-shaped Glass Ewer, which is examined in this study, with that of golden remains in the Silla era.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.238-238
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• 2012

현재 국내 주얼리(gold alloy) 제품을 생산함에 있어 주조 방법은 크게 대기 중 주조(흡입주조) 방법과 진공주조 방법으로 나누어진다. 국내 주얼리 제조업체의 약 90%이상이 대기 중에서 주조하는 흡입주조방법을 통해 제품을 제작하고 있고, 국외의 경우, 대다수 진공주조방법을 통해 제품을 제작하고 있다. 본 연구에서는 주얼리 제품을 생산할 때 사용되는 합금재료(master alloy)가 동일한 조건에서 주조방법을 달리하여 각각 24개씩 총 48개의 14K yellow gold alloy 제품을 제작한 후 열처리를 통해 각각의 기계적, 물리적 특성분석을 비교 분석하였다. EPMA (Electron Probe Micro Analysis)분석을 통해 합금재료 및 제품의 구성성분을 조사하였고, ICP-MS (Inductively Coupled Plasma Mass Spectroscopy)를 사용하여 성분에 대한 정량분석을 실시하였다. 용체화처리(solid solution treatment)는 $700^{\circ}C$, 30분의 조건으로 실시하였고, 시효경화처리(age-hardening)는 $200{\sim}300^{\circ}C$의 온도범위에서 $50^{\circ}C$ 간격으로 실시하였다. 열처리 전과 후 시료의 grain 들의 배열 및 size 변화를 관찰하기 위해 식각 후 OM (optical microscope) 및 SEM (Scanning Electron Microscope)를 통해 분석하였다. 열처리 전 제품의 경도측정결과 대기 중 흡입주조방법 및 진공 주조방법을 통해 제작된 제품이 각각 119 Hv, 126 Hv로 나타났고, 용체화 처리 후 98 Hv, 92 Hv로 감소하였다. 시효경화 처리 후의 경도변화는 대기 중 흡입주조 및 진공주조방법을 통해 제작된 제품 모두 $270^{\circ}C$에서 각각 154 HV, 166 HV로 가장 높은 경도 값을 나타내었고, $270^{\circ}C$ 이상에서는 과시효(over aging)현상으로 인해 경도 값이 다시 감소하는 경향을 나타내었다. EPMA mapping 분석을 통해 주조방법에 따라 각각 제품의 구성성분분포도를 확인하였다. 이를 통해 열처리 전 다소 불균일하게 분포되었던 성분들이 열처리 후 균일해짐을 확인할 수 있었다.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.3
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• pp.351-359
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• 2003

Statement of problem: Regardless of any restoration, most of case, we used in screw connection between abutment and implant. For this reason, implant screw loosening has been remained problem in restorative practices. Purpose: The purpose of this study was to compare surface of coated/plated screw with titanium and gold alloy screw and to evaluate physical property of coated/plated material after scratch test in FESEM investigation Material and methods: GoldTite, titanium screw provided by 3i (Implant Innovation, USA) and TorqTite, titanium screw by Steri-Oss (Nobel Biocare, USA) and gold screw, titanium screw by AVANA (Osstem Implant, korea) - were selected for this study. Each abutment screw surface was observed at 100 times, and then screw crest, root, and slope were done more detailed numerical value, at 1000 times with FESEM. A micro-diamond needle was also prepared for the scratch test. Each abutment screw was fixed, micro-diamond scratch the surface of head region was made at constant load and then was observed central region and periphery of fine trace through 1000 times with FESEM. Results: The surface of GoldTite was smoother than that of other kinds of screw and had abundant ductility and malleability compared with titanium and gold screw. The scratch test also showed that teflon particles were exfoliated easily in screw coated with teflon. Titanium screw had a rough surface and low ductility. Conclusion: It was recommended that the clinical use of gold-plated screw would prevent a screw from loosening. CLINICAL IMPLICATIONS Clinical use of gold-plated screw would prevent a screw from loosening because it had abundant ductility and malleability compared with titanium and gold screw.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.139-145
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• 2012

Gold nanoparticles (GNPs) have led to the development of a new field in the diagnosis and treatment of diseases such as cancer. An efficient synthesis of gold nanoparticles within the range of 8~57 nm was established by ${\gamma}-ray$ irradiation. The good point of a radiation-based method is the production of gold nanoparticles with a higher concentration and narrower size distribution compared with conventional methods. The size of gold nanoparticles was controlled using two methods. : (i) varying the ${\gamma}-ray$ irradiation dose of 10 to 25 kGy and (ii) varying the concentration of $HAuCl_4$ solution from 4 to 40 mM. In addition, the GNPs were radiolabeled using $[^{125}I]NaI$ in a simple and fast manner with high yields. The produced gold nanoparticles were characterized using a transmission electron microscopy (TEM), a UV-visible spectrophotometer, and a radio-TLC imaging scanner. From these results, these radiolabeled GNPs can be applicable for a radioisotope tag of biomolecules.

• Journal of the Korean institute of surface engineering
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• v.50 no.3
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• pp.170-176
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• 2017

EPIG (Electroless Pd/immersion Au) process was studied to replace ENIG (electroless Ni/immersion Au) and ENEPIG (electroless Ni/electroless Pd/immersion Au) processes for bump surface treatment used in high reliable flip chip packages. The palladium and gold layers formed by EPIG process were uniform with thickness of 125 nm and 34.5 nm, respectively. EPAG (Electroless Pd/autocatalytic Au) also produced even layers of palladium and gold with the thickness of 115 nm and 100 nm. TEM results exhibited that the gold layer in EPIG surface had crystalline structure while the palladium layer was amorphous one. After annealing at 250 nm, XPS analysis indicated that the palladium layer with thickness more than 22~33 nm could act as a diffusion barrier of copper interconnects. As a result of comparing the chip shear strength obtained from ENIG and EPIG surfaces, it was confirmed that the bonding strength was similar each other as 12.337 kg and 12.330 kg, respectively.

• Conservation Science in Museum
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• v.26
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• pp.143-160
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• 2021

The Seoul Baekje Museum has been conducting excavations at the Ancient Tomb Complex in Seokchon-dong, Seoul (Historic Site No. 243), known to be tombs of the royal family and the ruling class during the Hanseong period of the Baekje Kingdom. In this study, gold earrings that were revealed during the excavation underwent scientific analysis and conservation treatment. Stereo microscopy, SEM, X-ray imaging, CT, and XRF were applied in the analysis, and the characteristics, internal structure, and composition of the earrings as well as their production method were investigated. The results confirmed that the main hoops of the gilt-bronze earrings were made of copper cores gilt using mercury amalgamation. The findings also revealed that the hexahedron in the middle pendant was made by connecting small rings using molten gold powder, and the pendant sphere at the end was formed by soldering two hemispheres. As for the two thin-hoop earrings, they showed similar surface compositions but were made using different methods, with one made from a copper core wrapped with a gold plate and the other made by bending a gold rod. The gold content varied depending on the item and the place of measurement, but overall the earrings showed a relatively high gold content of approximately 19 to 21K. The purity of the golden earrings and the sophisticated manufacturing techniques applied indicate the high status of the buried person and of the tomb complex in Seokchong-dong.

• Journal of Acupuncture Research
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• v.39 no.4
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• pp.317-322
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• 2022

Gold thread therapy (GTT) continuously stimulates acupoints and is used to treat chronic conditions/diseases such as chronic lumbar pain. During the procedure gold thread is embedded into the skin and although gold thread is medically pure, GTT is an irreversible treatment where there is limited evidence on its safety. Here, we report a case of a 79-year-old woman being treated for low back pain who developed side effects following moving cupping therapy at a site of GTT (performed in the 1970s). Adverse reactions causing radiating pain persisted more than at least 9 days following moving cupping therapy. The symptoms of pain were evaluated using the numerical rating scale, and changes in tenderness and the state of bruising was recorded. Low back pain improved but the radiating low leg pain did not improve. This case highlights the need for caution when performing moving cupping therapy where GTT has been previously performed.

• The Journal of the Korean dental association
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• v.25 no.4 s.215
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• pp.359-363
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• 1987

72559 children, who visited the Dept. of Pedodontics, SNU Hospital from 1982 to 1985 were surveyed on the yearly tendency of dental treatment. The data were compared with those of previous reports, and the results were as follows, 1. The number out-patients were decreasing year by year. 2. Compared with those of 1982, in 1985, total number of visiting patient decreased to 14%, amalgam filling, 73.8% vital pulpotomy ; 69.55%, gold inlays ; 42.57%, Space maintainer ; 69.55%, tooth extraction ; 63.99% on the other hand, some items increased such as pulp extirpation ; 192%, canal filling ; 290%, 3. There revealed overall increasing tendency in almost all treatment items except Gold Inlay7s in from 1982 to 1985, compared with those from 1976 to 1979.

• Journal of the korean academy of Pediatric Dentistry
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• v.7 no.1
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• pp.7-11
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• 1980

6877 children who visited to pedodontic department from 1976 to 1979, were surveyed on the state of dental caries, therapic inclination a year and yearly tendency of treatment. The results were as follows ; 1. The prevalence of dental caries tended to show the increase in general year by year. 2. Girls had higher d.e.f. T. & S. index and D.M.F. T. & S. index than boys generally. 3. Distribution of therapy a year. (1979) Amalgam Filling 4464 Pulpotomy 952 S.P.-Crown 1538 Gold Inlay 250 Space Maintainer 341 Extraction 1313 Orthodontic Appliance 206 4. Tendency of treatment in 1979 (compared with 1976) No. of new patients 87.5% increased Amalgam Filling 50.0% increased Extraction 31.4% increased Orthodontic Appliance 267.9% increased S.P.-Crown 225.8% increased Gold Inlay 27.8% decreased Space Maintainer 2.3% decreased Pulpotomy 20.5% decreased.