• The Journal of Advanced Prosthodontics
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• 제5권3호
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• pp.262-269
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• 2013

PURPOSE. Perceived color of ceramics changes by the spectral power distribution of ambient light. This study aimed to quantify the amount of shifts in color and color coordinates of clinically simulated seven all-ceramics due to the switch of three ambient light sources using a human vision simulating spectroradiometer. MATERIALS AND METHODS. CIE color coordinates, such as $L^*$, $a^*$ and $b^*$, of ceramic specimens were measured under three light sources, which simulate the CIE standard illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp). Shifts in color and color coordinate by the switch of lights were determined. Influence of the switched light (D65 to A, or D65 to F9), shade of veneer ceramics (A2 or A3), and brand of ceramics on the shifts was analyzed by a three-way ANOVA. RESULTS. Shifts in color and color coordinates were influenced by three factors (P<.05). Color shifts by the switch to A were in the range of 5.9 to 7.7 ${\Delta}E{^*}_{ab}$ units, and those by the switch to F9 were 7.7 to 10.2; all of which were unacceptable (${\Delta}E{^*}_{ab}$ > 5.5). When switched to A, CIE $a^*$ increased (${\Delta}a^*$: 5.6 to 7.6), however, CIE $b^*$ increased (${\Delta}b^*$: 4.9 to 7.8) when switched to F9. CONCLUSION. Clinically simulated ceramics demonstrated clinically unacceptable color shifts according to the switches in ambient lights based on spectroradiometric readings. Therefore, shade matching and compatibility evaluation should be performed considering ambient lighting conditions and should be done under most relevant lighting condition.

• 한국세라믹학회지
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• 제55권4호
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• pp.368-375
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• 2018

This study deals with the color formation of ceramic pigment in the $TiO_2$-SnO-ZnO system. We designed compounds to control the color formation depending on the composition using the Design of Experiment. The color coordinate values of synthesized pigments, $L^*a^*b^*$ were measured and statistically analyzed color for changing elements depending on its composition. The relationship between the major crystalline phases and chromaticity was examined using XRD, and the oxidation states of each element were analyzed by XPS. The synthesized pigments based on the compound design exhibited various color changes ranging from yellow-orange to green-blue and brown. The statistical analysis on the spectrophotometer results shows that $a^*$ and $b^*$ values decreased with $TiO_2$ content, and increased with SnO content. Yellow-orange color was detected with the main peak of SnO, and the green-blue color developed with the main peak of $Zn_2TiO_4$. The $a^*$ and $b^*$ values increased with increased SnO peak intensity, and decreased with increased $Zn_2TiO_4$ peak intensity. The results revealed that pigment color formation was influenced by changes in the main crystalline phases and crystalline intensity. However, XPS analysis of the oxidation states of each element showed little correlation with the pigment chromaticity result.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.309-310
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• 1998

Visual observation and subjective assessments lack the objective evaluation of laser therapy effects of the epidermal pigmented lesions. In this study, we proposed the two methods; One is CIE(Commission International d'Eclairage) $L^*,\;a^*,\;b^*$ coordinate system($L^*$ : brightness, $a^*$ : red(+) $\sim$green(-) content, $b^*$ : yellow(+) $\sim$blue(-) content), and the other is the relative color difference measurement. And we applied these two methods for quantitative evaluation of the laser therapy effects.

• 공업화학
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• 제29권3호
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• pp.283-288
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• 2018

환경 친화적이고 질병을 유발시키지 않는 천연색소의 사용이 증가함에 따라 천연색소를 추출하는 다양한 방법이 연구되고 있다. 본 연구에서는 천연염료인 chlorophyll을 포함하고 있는 식물성 원료인 파슬리를 대상으로 천연색소를 추출하였다. 추출용매의 pH와 추출온도를 변수로 추출된 천연염료의 녹색계열의 목표색 코드 #50932C (L = 55.0, a = -40.0, b = 46.0)을 설정하고, 추출된 천연염료의 명도와 색좌표(L, a, b)의 정량적 수치로부터 색도분석을 수행하였다. 반응표면분석법에 의해 예측된 색도분석 중 색좌표 분석은 최적조건인 pH 8.0, 추출온도 $60.9^{\circ}C$에서의 이론적 수치 L (55.0), a (-36.3), b (36.8)를 나타냈고, 실제 실험으로 확인한 결과 L (69.0), a (-35.9), b (31.4)를 나타내, 이론 정확도 73.0%, 실제오차율은 13.8%로 확인되었으며, 색차분석의 ${\Delta}E$의 이론 최적화 값은 pH = 9.2 추출온도 $55.2^{\circ}C$에서 ${\Delta}E$ (12.4)이었고, 실제 실험의 경우 ${\Delta}E$ (13.0)로 나타났다. 색차 분석의 이론정확도 97.5% 및 실제 오차율은 4.5%를 나타냈다. 하지만, 색좌표의 조합이 목표색에 근사한 색을 나타내지 않았고, 단지 산술기하 평균적으로서 목표색에 근사함을 나타냈다. 따라서 천연염료 추출공정에 반응표면분석법을 적용시킬 경우 반응치로 색차 ${\Delta}E$에 비해 색좌표(L, a, b)를 이용하는 것이 색소추출공정의 최적화에 더 우수한 방법인 것으로 사료된다.

• Archives of Plastic Surgery
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• 제36권4호
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• pp.365-371
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• 2009

Purpose: Good color match holds a key position in facial reconstruction for good aesthetic result. To correct the wide facial soft tissue defect were usually used the tissue expanded cheek flap, deltopectoral flap or radial forearm free flap. This study is aimed to analyse the color difference after flap surgery by using chromameter. Method: From August 1995 to December 2006, 30 patients underwent flap operations were chosen randomly and evaluated color differences between flap site and adjacent skin. Reconstructive procedures included tissue expanded cheek flap(n = 10), deltopectoral flap(n = 10), and radial forearm free flap(n = 10). The measured sites were flap center within a radius of 1 ㎝ and four points of adjacent skin along the flap margin. The color was quantified in a three dimensional coordinate system $L^*$ (brightness), $a^*$ (redness), $b^*$ (yellowness). Results: There was no significant color difference between the pedicled flaps(tissue expanded cheek flap and deltopectoral flap) and adjacent skin area. On the other hand, color values of the radial forearm free flap were statistically different from those of adjacent skin area. Total color difference(${\Delta}E$) of tissue expanded cheek flap and deltopectoral flap were $7.45{\pm}5.78$ versus $9.41{\pm}7.09$, and that of radial forearm free flap was $11.74{\pm}3.85$. They suggest that pedicled flaps have a potential of better color match than radial forearm free flap. Conclusion: Thus, better esthetic result and satisfaction is more likely to be expected in pedicled flaps as long as it could be applied comparing radial forearm free flap.

• Archives of Plastic Surgery
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• 제35권1호
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• pp.36-41
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• 2008

Purpose: For facial reconstruction, skin color match is crucial to achieve great aesthetic result. Forehead flap and full thickness skin graft have been used for many years to reconstruct facial defect. Their results are aesthetically valuable with remarkable resemblance and harmony of the skin color between donor and recipient sites. The purpose of this study is to evaluate and compare the aesthetic outcome of the two methods as the analysis of skin color match. Methods: From January 1995 to December 2005, ten forehead flaps and ten full thickness skin grafts were performed. The reconstructed areas of forehead flaps were five noses and five eyelids. Recipient sites of full thickness skin grafts were seven eyelids, two noses and one forehead. In order to obtain the objective validity, the skin color of flap(or graft) and the recipient sites were measured by chromameter. The skin colors were quantified according to a three-dimensional coordinate system used in chromameter, L*(brightness), a*(redness), and b*(yellowness).Results: There was no significant color difference between forehead flap site and adjacent skin in all color values. On the other hand, the L* and b* values of graft sites were significantly lower than those of the adjacent skins. The a* values of graft sites were higher than those of the adjacent skins. Conclusion: This study reveals that skin color match of forehead flap is greater than that of full thickness skin graft. As forehead flap has adequate volume and great color match, it can be useful to reconstruct deep facial defect such as nasal defect. On the other hand, full thickness skin graft can be used for superficial defect like partial eyelid defect.

• 공업화학
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• 제27권3호
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• pp.325-329
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• 2016

환경 친화적이고 질병을 유발시키지 않은 천연색소의 사용이 증가함에 따라 천연색소를 추출하는 다양한 방법이 연구되고 있다. 본 연구에서는 천연염료인 brazilein, crocin, chlorophyll을 포함하고 있는 식물성 원료인 소목, 치자, 쑥을 대상으로 천연염료를 추출하였다. 추출용매의 pH와 추출시간을 변수로 추출된 천연염료의 적색, 황색, 녹색계열의 목표색을 설정하고 추출된 천연염료의 명도와 색의 좌표(L, a, b)의 정량적 수치로부터 색도분석을 수행하였다. 소목의 적색소인 brazilein과 치자의 황색소인 crocin의 경우 목표색인 카드뮴 레드와 카드뮴 옐로에 근접한 색상을 추출할 수 있었다. 추출시간 20 min을 기준으로 brazilein의 경우 pH 12, crocin의 경우 pH 9에서 색차를 나타내는 ${\Delta}E^*$가 각각 18.2와 18.4로 목표색과 유사한 색의 색소가 추출되었다. 그러나 쑥의 녹색색소인 chlorophyll의 경우 목표색인 크롬 그린과는 차이를 보였다.

• 공업화학
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• 제28권3호
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• pp.345-350
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• 2017

원자력연료 제조공정에서 생산되는 우라늄산화물(uranium oxide, UOX) 소결체의 밀도 분석은 일반적으로 소결공정을 거친 후, 소결체의 표본을 가지고 측정한다. 본 연구에서는 우라늄산화물의 중간물질인 중우라늄산암모늄(ammonium diuranate)의 색도를 분광기(spectrophotometer)로 측정함으로써 소결공정 이전에 우라늄산화물 소결체의 밀도를 분석해 보았다. 중우라늄산암모늄 표준 샘플 5개를 통해 얻은 명도 및 색의 좌푯(L, a, b)값과 통상적인 방법으로 얻은 소결체 밀도의 상관관계 추세선을 바탕으로 표적 샘플의 밀도를 분석한 결과, L 값에 대한 소결체의 밀도 분석이 결정계수 $R^2$ 값 0.9967로 가장 신뢰성이 높게 나왔음을 확인하였다. a 값에 대한 결정계수 $R^2$ 값은 0.9534로 상관관계가 높은 편이나 L 값보다는 낮았다. 이에 반해 b 값에 대한 결정계수 $R^2$ 값은 0.4349로 상관관계가 거의 없었다.

• 치위생과학회지
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• 제15권5호
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• pp.577-584
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• 2015

본 연구에서는 $1,040^{\circ}C$에서 예비소결한 Y-TZP 시편을 크롬 염화물 0.03~0.08 wt%, 테르븀 염화물 0.03~0.07wt%를 함유한 금속염화물 수용액에 3분간 침지하고서 $1,450^{\circ}C$에서 2시간 동안 소결하였으며, 이를 금속염화물 침투가 Y-TZP 소결체의 색상, 소결밀도, 굴곡강도 및 미세조직의 변화에 미치는 영향을 조사한 결과, 다음과 같은 결론을 얻었다. 지르코니아 예비소결체에 대한 크롬과 테르븀 염화물 침투로 A1, A2 및 A3에 근사한 색조의 재현이 가능하였다. 크롬과 테르븀 염화물을 첨가했을 때 지르코니아의 결정립 크기가 증가하였다. Y-TZP 소결체의 2축 굴곡강도는 크롬과 테르븀 염화물 침투에 의해서 유의한 변화를 보이지 않았다(p>0.05). X-선 회절 분석결과, 크롬과 테르븀 염화물의 첨가 여부와 함량에 따른 지르코니아 결정상의 차이점은 관찰되지 않았다. 이상의 결과로 크롬과 테르븀 염화물을 사용하여 지르코니아의 색상을 조절할 수 있음을 확인하였고, 착색된 지르코니아의 색상은 Vita shade guide의 색상과 다소 차이가 있었지만 임상에서 이중구조 세라믹 보철물 재작 시 사용 가능할 것으로 생각된다.

• 동아시아식생활학회지
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• 제17권6호
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• pp.894-902
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• 2007

This study was performed to observe the quality characteristics of Eunhakong dasik and Small Black Soybean dasik prepared with different addition rates of chlorella powder. For the Hunter's color values, the $L^*,\;a^*,\;and\;b^*$ values of both dasiks decreased with the addition of chlorella powder. The cohesiveness and gumminess of both dasiks were not dependant on the chlorella powder additions. However, the hardness of the Eunhakong dasik with 8% chlorella powder increased. The springiness and brittleness of the Eunhakong dasik had a tendency to decrease as the addition rate of the chlorella powder increased. In terms of sensory quality, both the dasiks were improved by the addition of 4% chlorella powder. Therefore, in subsequent examinations, the chemical characteristics of both dasiks were determined for the 4% addition of chlorella powder. The moisture and crude lipid contents of both dasiks were not influenced by the addition of chlorella powder. Carbohydrate content was highest in the Eunhakong dasik with 0% chlorella powder, and in the Small Black Soybean dasik with 4% chlorella powder. Conversely, crude protein content was highest in the Eunhakong dasik with 4% chlorella powder, and in the Small Black Soybean dasik with 0% chlorella powder. The crude lipid content of the Small Black Soybean dasik with 4% chlorella powder was lower than that of the control without chlorella powder. For mineral content, the K content of both dasiks was not influenced by the addition of chlorella powder. The Ca, Mg, and P contents of both dasiks with 4% chlorella powder, respectively, were lower than those of the dasik with 0% chlorella powder. Finally, the total amino acid content of the Eunhakong dasik tended to decrease, while that of the Small Black Soybean dasik incrased, with the 4% addition of chlorella powder.