• Journal of Pharmaceutical Investigation
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• 제34권6호
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• pp.465-469
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• 2004

Colloidal gold nanoparticles might be of use as nano scale delivery systems of various therapeutic materials in the future. Recent studies have reported the feasibility of colloidal gold nanoparticles as gene delivery systems or protein delivery systems. In this study, we aimed to develop a short-step method useful for screening the optimal coating conditions of colloidal gold nanoparticles with proteins. We observed that colloidal gold nanoparticles have properties of changing its unique color when they were exposed to NaCl solution. Taking advantage of the color changing properties of colloidal gold nanoparticles, we applied the color testing method of colloidal gold nanoparticles solutions for evaluating the protein coating nature. Using bovine serum albumin as a model protein, we tested the protein coating of colloidal gold nanoparticles via the color change upon NaCl addition. The optimal coating concentration and coating conditions of colloidal gold nanoparticles with bovine serum albumin were fixed using the color testing methods. We suggest that the color testing method might be applied to optimize the coating condition of colloidal gold nanoparticles with other therapeutic proteins.

• 한국재료학회지
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• 제28권4호
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• pp.221-226
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• 2018

The property changes of 18, 14, and 8K green gold alloys for jewelry are observed by adding 0.0, 3.0, and 5.0 wt% of indium (In), respectively. To check the composition of the alloys, an energy dispersive spectroscopy (EDS) analysis is conducted. Color and microstructure analysis is executed through bare-eye, macro camera, UV-VIS-NIR-colormeter, and optical microscope. The melting point, wetting angle, and hardness are measured using TGA-DTA, a wetting angle tester, and a Vickers hardness tester. The EDS analysis result demonstrates that each of the green gold alloys was manufactured with purposed contents. The color analysis result shows that the color of the alloys is similar to the color of the conventional 4 wt%-Cd 18K green gold, and the green color improves as the In content increases. The micro structure analysis result demonstrates that grain refinement improves as the amount of In increases. Enhancements in the melting point, wettability, and Vickers hardness changes appear as the In content increases and Au content decreases. The hardness is up to 260, which implies good durability. Therefore, the results suggest that the proposed 18, 14, and 8K In-added green gold alloys enhance the properties of jewelry products with regard to the green color, castability, and durability.

• 한국재료학회지
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• 제23권5호
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• pp.286-292
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• 2013

Generally, the color gold has had a biased conception due to its traditional use. Thus, this bias has resulted in a lack of usage of golden glaze on ceramics and also a lack of extensive studies of such glazes. In this paper, optimum conditions and mechanism of formation of gold color crystallization glaze containing $Fe_2O_3$(hematite), which is developed for gold colors of ceramic glazes, were studied. Experimental result showed that there are pyroxene based on diopside and $TiO_2$ phase in the base of a crystallization glaze with a value of $TiO_2$ of 6 wt% confirmed by XRD and Raman Spectroscopy. When $Fe_2O_3$ was used as a colorant for the gold color, the $TiO_2$ peak became extinct and the intensity of the diopside peak was sharper. Feldspar of 60 wt%, talc of 20 wt% and limestone of 20 wt% were used as the starting materials and these were tested using a three component system. The best result of test was selected and extended to its vicinity as an experiment to determine $TiO_2$ and $Fe_2O_3$ contents. The glaze with $TiO_2$ of 6 wt% and $Fe_2O_3$ of 12 wt% addition showed stable pyroxene based diopside crystals and the development of gold color. This gold color was obtained with CIE-$L^*a^*b^*$ values of 51.27, 4.46, 16.15 (a grayish yellow brown color), which was gained using the following firing conditions: temperature increasing speed $5^{\circ}C$/min, holding for 1 h at $1280^{\circ}C$, annealing speed $3^{\circ}C$/min till $1100{\circ}C$, holding for 2 h at $1100{\circ}C$, and finally natural annealing.

• 대한치과보철학회지
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• 제29권3호
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• pp.111-119
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• 1991

This study was performed to investigate the effect of gold electrodepositoin on porcelain color of palladium-silver alloy. The specimens were made by firing porcelain on the metal plates cast respectively in Au-Pt alloy, and Pd-Ag alloy. In the case of Pd-Ag alloy specimens, porcelain were fired under three different conditions of the metal plate: 1) without gold coating, 2) firing opaque beforehand on one side, gold coating on the other side, 3) gold coating on both sides of the metal plate. Color change was measured with fiber-optic colorimeter(Model TC-6FX, Tokyo Denshoku Co., Japan). The obtained results were as follows: 1. In the group of firing opaque beforehand on one side and gold coating on the other side, there was no significant differences in their color in comparison to the color of the control group of the Au-Pt alloys. 2. In the group of gold coating on both sides on metal plate, there were no significant differences except their value to the group of firing poaque beforehand on one side and gold coating on the other side.

• 대한치과보철학회지
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• 제41권2호
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• pp.148-159
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• 2003

Statement of problem Metal-ceramic restorations have been used extensively by dental clinicians for nearly 40 years. Strength an functional ability of metal-ceramic restorations are proved to be satisfying, However esthetics and biocompatibility of metal alloy which is used in metal-ceramic restoration is not ideal. Using pure gold as an alternative, have advantage of esthetics, biocompatibility over conventional metal alloy. But there had been little article which studied on the color effect of pure gold on fual porcelain color. Purpose The purpose of this study was to spectrophotometrically evaluate the difference between color of metal alloy(Au-Pt, Ni-Cr) and pure gold, during color masking procedure with opaque porcelain and to analyze the differences, Material and Methods Three types of metal - base metal(Ni-Cr), high gold alloy(Au-Pt), pure gold(GES) - specimen were fabricated 1cm in diameter. Four steps were established - after finishing, after pre-coditioning, after application of first opaque porcelain(0.08mm in thickness), after application of second opaque porcelain(0.15mm in thickness)- and tested color with spectrophotometer every each steps and analyzed with $CIEL^*a^*b^*$ color order system. One-Way ANOVA test was used to and out if there were significant differences between groups tested and Shaffe multiple comparison was used to identify where the differences were. Results 1. After finishing and pre-conditioning, pure gold(GES) group showed most high values in $L^*,a^*,b^*$. 2. After application of first opaque porcelain(0.08mm in thickness), after application of second opaque porcelain(0.15mm in thickness), pure gold(GES) group showed the least difference in $L^*,a^*,b^*$ values and the lowest ${\Delta}E$ value(${\Delta}E$=0.63). 3. After application of first opaque porcelain and after application of second opaque porcelain differences that were significant (P<0.05) between groups were found only in $a^*$ values. 4. Base metal alloy group showed the lowest $a^*$ value in test after application of first opaque porcelain and the highest value in test after application of first opaque porcelain Conclusion Pure gold group and high gold group showed higher $a^*$ values than base metal group when tested after 0.08mm thickness of opaque porcelain was applied and pure gold group showed much similar $L^*,a^*,b^*$ values between 0.08mm thickness and 0.15mm thickness of opaque porcelain. This meant that pure gold was more easily masked by opaque porcelain than the other two groups.

• 한국재료학회지
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• 제27권7호
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• pp.381-385
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• 2017

In order to replace 14K white gold alloys, the properties of 5K white gold alloys (Au20-Ag80) were investigated by changing the contents of In (0.0-10.0 wt%). Energy dispersive X-ray spectroscopy (EDS) was used to determine the precise content of alloys. Properties of the alloys such as hardness, melting point, color difference, and corrosion resistance were determined using Vickers Hardness test, TGA-DTA, UV-VIS-NIR-colorimetry, and salt-spray tests, respectively. Wetting angle analysis was performed to determine the wettability of the alloys on plaster. The results of the EDS analysis confirmed that the Au-Ag-In alloys had been fabricated with the intended composition. The results of the Vickers hardness test revealed that each Au-Ag-In alloy had higher mechanical hardness than that of 14K white gold. TGA-DTA analysis showed that the melting point decreased with an increase in the In content. In particular, the alloy containing 10.0 wt% In showed a lower melting temperature (> $70^{\circ}C$) than the other alloys, which implied that alloys containing 10.0 wt% In can be used as soldering materials for Au-Ag-In alloys. Color difference analysis also revealed that all the Au-Ag-In alloys showed a color difference of less than 6.51 with respect to 14K white gold, which implied a white metallic color. A 72-h salt-spray test confirmed that the Au-AgIn alloys showed better corrosion resistance than 14K white gold alloys. All Au-Ag-In alloys showed wetting angle similar to that of 14K white gold alloys. It was observed that the 10.0 wt% In alloy had a very small wetting angle, further confirming it as a good soldering material for white metals. Our results show that white 5K Au-Ag-In alloys with appropriate properties might be successful substitutes for 14K white gold alloys.

• 대한치과보철학회지
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• 제33권4호
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• pp.645-661
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• 1995

As the mechanical property of composite resin improved, composite resin has been widely used esthetic dentistry. In the field of esthetic dentistry, the color of prosthetic material is very important. The purpose of this study was to evaluate the color difference of specimens, by the types of alloys and gold electrodeposit. Experimental groups were as follows : Group Prec : Au-Pt alloy with no gold coating and no resin veneer. Group Semi : Pd-Ag alloy with no gold coating and no resin veneer. Group BAse : Ni-Cr alloy with no gold coating and no resin veneer. Group Gsem : Pd-Ag alloy with no gold coating and no resin veneer. Group Gbas : Ni-Cr alloy with no gold coating and no resin veneer. Group PreR : Resin veneer on the Pd-Ag alloy without gold coating. Group SemR : Resin veneer on the Pd-Ag alloy without gold coating. Group GbsR : Resin veneer on the Ni-Cr alloy with gold coating Group BasR : Resin veneer on the Ni-Cr alloy without gold coating. In this study, colors of metal surfaces and veneered resins were evaluated by the CIE $L^{*}a^{*}b$ system. The results obtained were as follows : 1. different alloy types and gold coating make the $L^{*}a^{*}b$ system. 2. The ${\Delta}E^*$ab value between groups semi and Base was less than 1.5 and there was no $a^*$ and $b^*$ value difference between groups Gsem and Gbas 3. The values of $L^*$ and $a^*$ ain groups GsemR and GbasR were so similar that the ${\Delta}E^*$ab value was as small as 0.58. 4. In resin specimens with gold coated semiprecious or base alloys showed yellower and redder deviation than the resin specimens with precious alloy. 5. The ${\Delta}E^*$ab values between goups PreR-GsemR and groups PreR-GbasR were as small as 2.68 and 2.22 respectively.

• 보존과학회지
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• 제27권4호
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• pp.403-414
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• 2011

본 연구는 2007년 국립중앙박물관 소장유물인 고려시대 화금청자 2점과 중국 북송시기 화금도자 3점의 금 잔존여부 및 금채의 채색기법 연구를 바탕으로 고려시대 금채장식을 재현 실험하였다. 도자기 시편 위에 4개의 교착제와 금분을 섞어 금채 후 $100^{\circ}C{\sim}1200^{\circ}C$까지 단계별 번조하여 표면의 교착상태와 발색력을 현미경과 색도를 관찰하였다. 이를 통해 각 교착제에 따른 시각적 효과와 적정온도를 파악하였고, 그 중 기름과 아교가 가장 뛰어난 교착력과 발색력을 보이는 것을 알 수 있었다. 이에 따라 완형의 현대 재현 고려 상감청자의 유약 표면에 기름과 아교를 각각 금채한 후 적정온도인 $700^{\circ}C{\sim}800^{\circ}C$에서 번조하였으며, 두 교착제가 유약 위에 교착된 상태를 파악하기 위해 금채의 단면을 SEM으로 관찰하였다. 그 결과, 교착력은 차이가 없었으나, 발색력, 밀도 등은 아교가 다소 떨어지는 차이가 있었다. 또한 기름은 실온에서 건조되지 않는 반면, 아교는 건조되는 장점으로 작업성이 좋은 편이었다. 이에 반해, 아교는 작업성 측면에서는 기름에 비해 매우 뛰어난 장점을 보였으나 발색력에서는 기름에 비해 다소 떨어지는 것을 이번 실험을 통해 알 수 있었다.

• 복식
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• 제58권3호
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• pp.123-130
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• 2008

Symbolizing holiness, wealth and power, golden color was most effective to express the absolute power of royal family and aristocratic society as well as the beauty of magnificent and brilliant authority. Such golden color was understood as the artistic color formed in the dictatorial society as well as the society under the rule of absolute monarch. Thus, it has been used in the costume that symbolizes nobleness, holiness, brilliancy, ethnicity and future-oriented property. In this sense, the image of golden color shown in contemporary fashion was analyzed as follows in this research: First, showing the future-oriented image, golden color expresses avant-garde, cyber and cosmic future-oriented image by using diverse new materials which introduce the state-of-the-art technology sense in addition to metallic textile. Second, getting hint from the ethnic costume of many countries around the world such as brilliant embroidery using golden-thread, ornament with exaggerated technique such as gold foil, mark and character in peculiar tint, the ethnic image of golden color expressed the peculiar color or materials of ethnic costume, handicraft details, etc in golden color. Third, since golden color is expressed in ostentatious image to which elegance and luxuriousness that looks like the work of haute-couture costume of royal family or sensuality that voluptuously expresses the beautiful body line of women are added, the viewers are enchanted or attracted.

• 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.