• Journal of Microbiology and Biotechnology
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• 제26권10호
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• pp.1668-1674
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• 2016

Red ginseng, a steamed and sun-dried ginseng, is a popular health-promoting food in Korea and other Asian countries. We introduced nanofertilizer technology using gold nanoparticles in an effort to develop red ginseng with an elevated level of ginsenosides, the main active compounds of ginseng. Shoots of 6-year-old ginseng plants were fertilized three times with colloidal gold nanoparticle sprays. Red ginseng extract was prepared from the main roots. The concentrations of gold and ginsenosides were measured following gold nanoparticle treatment. To evaluate the anti-inflammatory effects, mouse peritoneal macrophages of male BALB/c mouse were stimulated with lipopolysaccharide plus interferon-γ in the presence of extracts from red ginseng with or without gold nanoparticle treatment. The content of ginsenosides, such as Rg1, Re, Rf, and Rb1, increased in ginseng treated with gold nanofertilizer whereas the steaming process increased only the levels of Rd and Rg3. The levels of nitric oxide, inducible nitric oxide synthase, and interleukin-6, but not tumor necrosis factor-α, were more suppressed in macrophages treated with extract from gold nanoparticle-treated red ginseng. Our results show that the use of a colloidal gold nanoparticle fertilizer improved the synthesis of ginsenosides in ginseng and enhanced the anti-inflammatory effects of red ginseng. Further research is required to elucidate the causal factors for the gold-induced change in ginsenoside synthesis and to determine the in vivo effect of gold nanoparticle-treated ginseng.

• 한국재료학회지
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• 제27권7호
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• pp.386-391
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• 2017

Using a customized diffusion bonder, we executed diffusion bonding for ring shaped white gold and red gold samples (inner, outer diameter, and thickness were 15.7, 18.7, and 3.0 mm, respectively) at a temperature of $780^{\circ}C$ and applied pressure of 2300 N in a vacuum of $5{\times}10^{-2}$ torr for 180 seconds. Optical microscopy, field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) were used to investigate the microstructure and compositional changes. The mechanical properties were confirmed by Vickers hardness and shear strength tests. Optical microscopy and FE-SEM confirmed the uniform bonding interface, which was without defects such as micro pores. EDS mapping analysis confirmed that each gold alloy was 14K with the intended composition; Ni and Cu was included as coloring metals in the white and red gold alloys, respectively. The effective diffusion coefficient was estimated based on EDS line scanning. Individual values of Ni and Cu were $5.0{\times}10^{-8}cm^2/s$ and $8.9{\times}10^{-8}cm^2/s$, respectively. These values were as large as those of the melting points due to the accelerated diffusion in this customized diffusion bonder. Vickers hardness results showed that the hardness values of white gold and red gold were 127.83 and 103.04, respectively, due to solid solution strengthening. In addition, the value at the interface indicated no formation of intermetallic compound around the bonding interface. From the shear strength test, the sample was found not to be destroyed at up to 100,000 gf due to the high bonding strength. Therefore, these results confirm the successful diffusion bonding of 14K white-red golds with a diffusion bonder at a low temperature of $780^{\circ}C$ and a short processing time of 180 seconds.

• 보존과학회지
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• 제32권1호
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• pp.43-49
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• 2016

금사는 금속물로 제작된 실을 의미하며, 다양한 재료와 재질이 혼합하여 사용되고, 제작 방식에 따라 다양한 형태가 구분된다. 같은 형태일지라도 지역에 따라 사용재료가 다르게 나타나기 때문에 금박, 접착제, 배지 등에 대한 기초 자료 조사는 제작기법 및 유물의 제작국가에 대한 정보를 확인할 수 있기에 중요하다. 이에 본 연구는 직금 유물에 사용된 전통 편금사의 접착특성 및 제작기법 분석을 위한 연구를 진행하였다. 지역 및 시대가 다른 직금 유물을 선정하여 시료를 일부 채취하였다. 전통 금사에 사용했을 것으로 추정되는 접착제를 선정하여, 종류별로 표준시료를 제작하였다. 접착제는 아교, 주토 혼합 아교, 옻, 주칠을 선정하였으며, 식물성 배지인 한지 위에 접착제를 바른 후 순금박을 올렸다. 직금유물에서 채취한 금사와 제작한 표준시료를 일부 채취하여 형태 및 무기원소 성분 분석을 하였다. 연구 결과, 편금사는 금박층, 접착층, 배지층으로 구분이 되는 것을 확인할 수 있었다. 표준시료와 비교 관찰한 결과, 아교 및 주칠혼합시료와 형태적으로 유사하였다. 붉은색 접착층에 대한 정성분석 결과 알루미늄(Al), 규소(Si), 철(Fe) 성분이 현미경에서 관찰된 붉은색과 일치함에 따라 전통 편금사는 아교에 주토를 혼합하여 접착제로 사용한 것으로 판단된다. 이러한 사실은 국내 문헌 및 국외사례를 통해서도 확인할 수 있으며, 아교에 주토를 혼합함으로써 발색 및 평활도에서 효과를 얻고자 함으로 사료된다. 또한 이러한 방법은 옻을 접착제로 사용하는 일본과는 달리 중국, 한국에서 공통적으로 관찰되는 제작방법이라는 사실도 확인할 수 있었다.본 연구를 통해 향후 전통 금사의 재현 및 생산기술에 대한 기초 자료로 활용될 것으로 기대된다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권10호
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• pp.4311-4317
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• 2014

Background: Nano-biotechnology is recognized as offering revolutionary changes in the field of cancer therapy and biologically synthesized gold nanoparticles are known to have a wide range of medical applications. Materials and Methods: Gold nanoparticles (GNPs) were biosynthesized with an aqueous extract of the red alga Corallina officinalis, used as a reducing and stabilizing agent. GNPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive analysis (EDX) and Fourier transform infra-red (FT-IR) spectroscopy and tested for cytotoxic activity against human breast cancer (MCF-7) cells cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, considering their cytotoxicty and effects on cellular DNA. Results: The biosynthesized GNPs were $14.6{\pm}1nm$ in diameter. FT-IR analysis showed that the hydroxyl functional group from polyphenols and carbonyl group from proteins could assist in formation and stabilization. The GNPs showed potent cytotoxic activity against MCF-7 cells, causing necrosis at high concentrations while lower concentrations were without effect as indicated by DNA fragmentation assay. Conclusions: The antitumor activity of the biosynthesized GNPs from the red alga Corallina officinalis against human breast cancer cells may be due to the cytotoxic effects of the gold nanoparticles and the polyphenolcontent of the algal extract.

• 한국재료학회지
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• 제28권2호
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• pp.89-94
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• 2018

The properties of 18 K red gold solder alloys were investigated by changing the content of In up to 10.0 wt% in order to replace the hazardous Cd element. Cupellation and energy dispersive X-ray spectroscopy (EDS) were used to check the composition of each alloy, and FE-SEM and UV-VIS-NIR-Colormeter were employed for microstructure and color characterization. The melting temperature, hardness, and wetting angle of the samples were determined by TGA-DTA, the Vickers hardness tester, and the Wetting angle tester. The cupellation result confirmed that all the samples had 18K above 75.0wt%-Au. EDS results showed that Cu and In elements were alloyed with the intended composition without segregation. The microstructure results showed that the amount of In increased, and the grain size became smaller. The color analysis revealed that the proposed solders up to 10.0 wt% In showed a color similar to the reference 18 K substrate like the 10.0 wt% Cd solder with a color difference of less than 7.50. TGA-DTA results confirmed that when more than 5.0 wt% of In was added, the melting temperature decreased enough for the soldering process. The Vickers hardness result revealed that more than 5.0 wt% In solder alloys had greater hardness than 10.0 wt% Cd solder, which suggested that it was more favorable in making a wire type solder. Moreover, all the In solders showed a lower wetting angle than the 10.0 wt% Cd solder. Our results suggested that the In alloyed 18 K red gold solders might replace the conventional 10.0 wt% Cd solder with appropriate properties for red gold jewelry soldering.

• 한국재료학회지
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• 제30권8호
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• pp.393-398
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• 2020

We propose a novel stripping solution containing acids (HCl and HNO₃), an oxidant [(NH₄)₂S₂O₈], and complexing agents (NaCl and citric acid) to remove surface passivation layers from 14K gold alloys fabricated using an investment casting process. The optimized solution employing only HCl acid is determined by varying molar fractions of HCl and HNO₃ on 14K yellow gold samples. Stripping properties are also identified for red and white gold alloy samples under the optimized stripping conditions. The removal of passivation layers, weight loss, and microstructure evolution are characterized using Raman spectroscopy, a precision scale, and optical microscopy. The proposed stripping solution effectively removes passivation layers more rapidly than conventional cyanide stripping. Weight loss increases linearly for up to 5 min for all 14K gold alloys. Red gold exhibits the greatest weight loss, followed by yellow gold and white gold. The results of microstructural analysis reveal that the conformal stripping occurs according to time. These results imply that the proposed oxidative chloride stripping might replace conventional cyanide stripping.

• 보존과학회지
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• 제16권
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• pp.52-63
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• 2004

본 연구는 사적 259호 고려 선원사지 출토 금동축수를 통하여 기존의 기술사, 야금사로 제한되어 왔던 국내연구에서 벗어나 고대에도 현대 금속공예에서와 같이 경제적, 장식적인 목적 등으로 금 합금이 이루어 졌을 것이라는 가정 하에 고대 금동유물들과 선원사지 출토유물과의 연관성과 함께 표면색에 따른 금 함량비의 차이를 밝혀보고자 하였다. 그 결과, 선원사지 출토유물은 금 도금층의 표면색에 따라 육안관찰에 의한 Gold, White-Gold. Red-Gold의 세 가지로 나눌 수 있었으며, 금도금의 표면색에 따라 금 함량의 차이가 나는 것을 확인할 수 있었다. 세 가지의 표면 색중 금 이외의 물질인 Cu가 많게는 $43.0\%$ 정도가 포함되어 있는 것으로 보아 Red-Gold type은 Cu를 합금하였을 가능성이 있는 것으로 보인다. 도금된 금동시료의 피복기술은 수은이 $0.92\~19.04\%$가 검출됨으로써 수은을 사용한 수은아말감 도금법이 적용되었으며, 금 알갱이가 관찰되고 도금피막 두께는 $2.5\~25{\mu}m$로 도금기법 및 광쇠질의 차이로 인해 부분적으로 매우 불균일한 것으로 보아 금분 아말감을 하고 광쇠질로 광택을 낸 것으로 보인다. 또한 소지금속은 두 가지 방법으로 제작되었는데 하나는 순수한 Cu를 주조하여 제작한 것이고 다른 하나는 거의 순수한 동판을 말아 연접되는 곳에 주석땜을 하여 제작하였다. 또한 주석땜을 하는 과정에서 주석땜이 외부에 묻어있는 곳은 도금되지 않은 것으로 보아 축수의 모양을 만든 후 금도금 작업한 것임을 알 수 있었다.

• 한국식생활문화학회지
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• 제30권2호
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• pp.220-226
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• 2015

This study was to conducted to investigate the antioxidative activity of 70% ethanol extracts of kiwi of three different colors (gold, green and red) by measuring DPPH, ABTS radical scavenging activity, tyrosinase inhibitory effect, metal chelating effect, reducing power, and nitrite scavenging activity. Total polyphenol contents were: gold kiwi, 3.09 mg GAE/g, green kiwi 2.71 mg GAE/g, and red kiwi 4.59 mg GAE/g, respectively. Red kiwi showed higher antioxdidant activity than gold and green kiwi. DPPH and ABTS radical scavenging activity, and nitrite scavenging activity of red kiwi exhibited 94.83, 99.57, and 97.88%, respectively, at a concentration of 20 mg/mL, which were equal to those of ascorbic acid (positive control). Metal chelating effect of red kiwi was superior to that of ascorbic acid. Therefore, the availability of red kiwi will be increased in the field of functional material for food additives and value added products.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1341-1345
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• 2006

An electrostatic interaction is responsible for the attachment of gold seeds of 1-3 nm onto APTMS (3-aminopropyl trimethoxysilane)-coated silica cores in the formation of gold clusters. A surface plasmon resonance and morphology of gold clusters were significantly affected by the pH of gold colloids prepared by THPC reducing agent. Gold colloids of alkaline pH induced the heterogeneous deposition of gold seeds onto the silica nanoparticles, probably due to the continuous reduction of residual gold ions during the attachment process. Gold colloids of acidic pH induced the monodisperse deposition of gold seeds, consequently leading to the formation of smooth gold layer on the silica nanoparticles surface. The gold nanoshells (core radius = 80 nm) prepared by gold colloids of pH 3.1 exhibited the more red-shift and relatively stronger intensity of plasmon absorption bands, compared with gold nanoshells prepared by alkaline gold colloids of pH 9.7.

• 복식
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• 제50권7호
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• pp.15-31
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• 2000

1. After the Chu Dynasty(周代), we can confirm the fish shape mark made of stones as the relics of the Chunkuk dynasty(戰國時代). In the Shu Dynasty(隋代), the system of bamboo and the rabbit shape mark made of silver into the fish shape mark. As it were, made of bamboo or siltier changed into the fish shape mark made of jade, gold, silver or wood. 2. In the Dang Dynasty(唐代), the used the fish shape credit mark made of jade, gold, silver, copper or textile, according to their classes. According to one's posit the man who wore purple, red coat, credit mark made a gold and silver. attached with putting them in fish bags. 3. In the Ryo Dynasty(遼代), there was also a system of attaching marks. The emperor was hanging the fish shape and the officials attached the double fish shape to the common dress. fish shape of jade. gold, amber, agate, silver or copper. without any fish bag. 4. The Song Dynasty(宋代) followed the system of the Dang Dynasty they used only the fish shape bags without marks in them. Hanging the fish shape bags made of gold and silver at the back side of the belt. 5. The Gin Dynasty(金代) carried out the system of made jade, gold or silver like the Dang, Song and Ryo Dynasty. In the Sejong Kingdom a system of paper card was carried out as the credit mark of the eighth and the ninth grade. 6. In the Ming Dynasty(明代), the military official general attached the golden, silver, ivory of jade, wood and copper cards with their positions and names. 7. Following the Dang Dynasty, Japan made of fish shape bags to their clothes. Colors of their fish shape marks were same as their clothes. They made the marks, such as crystal, cow's horn, lead and nickel and plated them with gold or silver. 8. In Korea, Pohai(발해) established the fish shape credit mark differed in material. gold, silver or copper according to their positions. We can confirm the Unified Silla(南國;統一新羅), carried out the system of attaching the fish shape in Chonma Chong(천마총), Golden Crown Chong(金冠塚), the King's 13-17 belt ring unearthed at the north part of Court South threat Chong(황남대총), the fish shape golden or silver, to their purple or red ceremonial coats. In the Koryo Dynasty(高麗), like the Dang, Song and Pohai, they attached the fish shape golden or silver marks, to their purple or red ceremonial coats.