• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.363-371
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• 2001

심미성 수복재 중합시 사용되는 광원은 다양한 요인들에 의해 선택되어지고 있지만 이러한 요인들은 앞으로도 논란의 여지를 많이 남겨두고 있다. 또한 현재 사용되고 있는 중합법들이 제각기 독특한 장점들을 갖고 있기 때문에 최적의 중합법 결정이 필요한 시점이다. 이에 본 연구에서는 중합광의 강도(50, 100, 200, 300, 400, 600mW/$\textrm{cm}^2$)와 중합시간(10, 20, 40초)을 다양하게 변화시켰을 때 복합레진의 미세경도와 미세누출도가 어떠한 양태를 보이는지를 관찰하고자 하였다. 본 실험에서는 A3 색상의 혼합형 복합레진인 국산 DenFil과 미세입자형 복합레진인 Esthet X를 사용하였다. 중합 1일 후 복합레진의 Vickers 경도는 다이아몬드형 압흔 길이를 측정하여 평가하였으며 미세누출도는 1% methylene blue용액을 이용한 방법과 주사전자 현미경을 이용한 수복물과 치질간의 최대 이개도 평가법의 두 가지 방법으로 측정하였다. 본 연구의 결과는 다음과 같다; 1. 미세경도는 시편 상면이 하면에 비해 단단한 양태를 보였으며 상, 하면에 관계없이 혼합형 복합레진인 국산 DenFil이 미세입자형 복합레진인 Esthetx에 비해 높은 경도치를 보였다. 2. 모든 미세 경도 실험에서 너무 낮은 광도(50mW/$\textrm{cm}^2$, 100mW/$\textrm{cm}^2$)로 중합한 군에서는 대조군에 비해 유의하게 낮은 미세 경도를 보였다(p<0.05). 3. 상면의 경우, DenFil은 중합시간과 관계없이 200mW/$\textrm{cm}^2$ 이상의 광도에서 대조군(600mW/$\textrm{cm}^2$ 광도로 40초간 중합)과 유의차 없는 미세경도치를 보였으나, Esthet X는 200mW/$\textrm{cm}^2$ 이상의 광도로 40초 동안 중합한 군에서만 대조군과 유의차 없는 미세경도치를 보였다. 4. 하면의 경우 DenFil은 300mW/$\textrm{cm}^2$ 이상의 광도로, Esthet X는 200mW/$\textrm{cm}^2$ 이상의 광도로 각기 40초 동안 중합한 군에서만 대조군과 유의차 없는 미세경도치를 보였다. 5. 법랑질 변연부에서는 색소 침투가 전혀 없었으나 상아질 변연부에서는 정도의 차이는 있었지만 모든 시편에서 색소 침투를 보였다. 6. 통계적 유의차는 없었지만 저광도에서 우수한 미세누출도를 보였으며 색소 침투법과 최대 이개도 평가법간에는 상관성이 매우 낮았다 (p=0.801).

• Restorative Dentistry and Endodontics
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• v.24 no.4
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• pp.585-603
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• 1999

Esthetic availabilities used as an esthetic restorative maternals can be determined by the optical coincidence among materials, enamel and dentin. Enamel is highly translucent. That's why esthetic materials need to correspond the close translucency of enamel. But the translucent materials are affected by the background color. So it should be predicted that the color of estorative materials depend on the any thickness and the spectral reflectance of the background on which they are placed. The object of this investigation, under above hypothesis, was to determine and analyze how they affect the final color according to the thickness, translucency and background color (white, black and dentin) fill three commercial light cured composite resins(Charisma, Spectrum TPH and Z100). And correlation was analyzed to find out the possibility of the prediction when using the certain background color and thickness of materials. Followings are the result 1. The I shade of CHA showed the lowest contrast ratio($Co_7$) while the B3 shade of Z100 showed the highest contrast ratio(p<0.05). 2. The value of $L^*$ and $b^*$ on the white and dentin background is increased with decreasing thickness. And there are significant relationships between increasing thickness and each value(R>0.085). But there is a little change of $L^*$ and $b^*$ value on the black background regardless of the thickness(p>0.05). 3. For the $a^*$ value, there was little difference in values as a function of thickness and changed irregularly regardless of thickness in all background. 4. The pattern of increasing value of $L^*$ and $b^*$ with decreasing thickness was similar to the group of white and dentin background. In both dentin one showed lesser change of value. 5. The values of $L^*a^*b^*$ measured on the different background with same thickness showed the recognizable color difference(${\Delta}E^*$>2) when the thickness was below 2.6mm. 6. Contrast ratio was increased with increasing thickness with significant relationship (R>0.9). 7. Spectral reflectance of composite resins that calculated from Kubelka-Munk equation was showed little difference compared with observed value w1th decreasing thickness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.443-449
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• 2015

In this paper, we proposed Channel allocation scheme according to the user's location with IR. In VLC System, LED can generate various colors of light by controlling the mixing ratio of each individual RGB color element. Thus, each RGB channel will have a different signal power, and each channel will have different performance. This proposed system using Visible light(RGB) as way to transmit signals, it depends on the mixture RGB, which decided the color of light, moreover, each things determined their performance. However, if the signal were fixed allocated RGB to transmit such as the original system, the importance of the each signals a different occur the limit on the quality of signals. To solve this problem in this paper, according to the RGB mixture ratios analyze the performance for the LED, which analyzed based on allocating the signal by transmitting to improve the quality was about how researched. In addition, our proposed system is able to improve the performance of BER and satisfied the Qos to desire users.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.167-167
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• 2013

최근에 산화물 형광체는 황화물 형광체에 비해 높은 화학적 안정성을 나타내기 때문에 백색 발광 다이오드, 전계방출 디스플레이와 플라즈마 디스플레이 패널에 그 응용성을 넓히고 있다. 마그네슘 니오베이트(magnesium niobate, MgNb2O6)는 우수한 유전 특성(상대 유전상수=18.4)을 나타내기 때문에 마이크로파 유전체로 응용 가능하며, 단일상 릴랙서 페라브스카이트(relaxor perovskite) Pb(Mg1/3Nb2/3)O3을 합성하기 위한 전구체 (precursor)로 널리 사용되고 있으며, 나이오븀산염 이온에서 다양한 색상을 방출하는 활성제 이온으로 효율적인 에너지 전달이 일어남으로써 Sm3+, Dy3+, Eu3+와 같은 희토류 이온의 좋은 모체 격자로 개발할 수 있다. 본 연구에서는 마그네슘 니오베이트 MgNb2O6 모체 결정에 다양한 활성제 이온, 즉 Eu3+, Sm3+, Dy3+, Tb3+를 선택적으로 주입하여 발광 효율이 높은 천연색 형광체를 합성하고자 한다. 특히, 모체 결정에 주입되는 활성제 이온 주위의 국소적인 환경이 반전 대칭에서 변형되는 척도를 조사하여 활성제의 주 발광 파장의 세기가 최대가 되는 최적의 조건을 결정하고자 한다. Mg1-1.5xNb2O6:REx3+ 형광체 분말 시료는 초기 물질 MgO, Nb2O5와 희토류 이온을 화학 반응식에 맞게 정밀 저울로 측량하여 플라스틱 용기에 ZrO2 볼과 함께 넣고, 소정의 에탄올을 채운 뒤 밀봉하고서, 300 rpm의 속도로 20시간 볼밀 (ball-mill) 작업을 수행하였다. 그 후, 체(sieve)로 ZrO2 볼을 걸러낸 다음에 혼합된 용액을 각 비커에 담아서 $40^{\circ}C$의 건조기에서 24시간 건조하였고, 건조된 시료를 막자 사발에 넣고 잘게 갈고 80 ${\mu}m$의 체로 걸러낸 후에, 알루미나 도가니에 활성제 이온별로 각각 담아, 전기로에 장입하여 매분당 $5^{\circ}C$의 비율로 온도를 상승시켜 $350^{\circ}C$에서 5시간 동안 하소 공정을 실시한 후에, 온도를 계속 일정한 율로 증가시켜 $1,200^{\circ}C$에서 5시간 동안 소성하여 합성하였다. 합성된 형광체 분말의 결정 구조는 $Cu-K{\alpha}$ 복사선(파장: 1.5406)을 사용하여 X-선회절장치로 측정하였으며, 형광체의 표면 형상은 전계형 주사전자현미경으로 관측하였다. 흡광와 발광스펙트럼은 제논 램프를 광원으로 갖는 형광 광도계를 사용하여 측정하였다. 모체 결정에 활성제 이온 Eu3+, Sm3+, Dy3+, Tb3+가 도핑된 형광체 분말은 각각 적색, 주황색, 황색, 녹색 발광이 관측되었다. 각 발광 스펙트럼과 결정 입자의 크기와 형상 사이의 상호 관계를 조사하였다. 실험 결과로부터, 각 형광체의 발광 파장은 활성제 이온의 종류 와 서로 밀접하게 관련되어 있으며, 형광체 시료 합성시 활성제 이온의 농도를 선택적으로 조절함으로써 발광의 세기를 제어할 수 있음을 확인하였다.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.147-161
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• 2021

Through photogrammetry techniques, what current researches can achieve at present is rough 3D mesh and color map of objects, rather than usable photo-realistic 3D assets. This research aims to propose a new method to create photo-realistic 3D assets that can be used in the field of visualization applications. The new method combines photogrammetry with computer graphics modeling. Through the description of the production process of three objects in the real world - "Bullet Box", "Gun" and "Metal Beverage Bottle," it introduces in details the concept, functions, operating skills and software packages used in the steps including the photograph object, white balance, reconstruction, cleanup reconstruction, retopology, UV unwrapping, projection, texture baking, De-Lighting and Create Material Maps. In order to increase the flexibility of the method, alternatives to the software packages are also recommended for each step. In this research, 3D assets are produced that are accurate in shape, correct in color, easy to render and can be physically interacted with dynamic lighting in texture. The new method can obtain more realistic visual effects at a faster speed. It does not require large-scale teams, expensive equipment and software packages, therefore it is suitable for small studios and independent artists and educational institutions.

• Journal of the Society of Disaster Information
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• v.18 no.4
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• pp.806-816
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• 2022

Purpose: In this study, the luminance measurement analysis results of the smoke generation state are considered for visual signal display light color for real-time escape guidance in the underground common area. Method: We will analyze the scattering characteristics of light in the atmosphere and optical technology based on the visibility theory, and try to classify the elemental technology as a guidance function through a prototype of a visual signal display device for evacuation guidance. Result: In the experiment conducted under the smoke-generating condition, the results were derived with low luminance ratio and good visibility in the order of red, green, and yellow. However, this result is different from general lighting in which color rendering is considered, and is limited to signals for signals and detection. Conclusion: A conclusions were drawn by reflecting both the luminance measurement results in the smoke generation situation and the preference survey results conducted in previous studies for the light color of the visual signal for signal and detection. When events such as smoke occur, it is better to use the escape guidance visual signal in red or green.

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.128-137
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• 2005

In this study we measured the amount of light energy that was projected through the tooth material and analyzed the degree of polymerization by measuring the surface hardness of composites. For polymerization, Optilux 501 (Demetron, USA) with two types of light guide was used: a 12 mm diameter light guide with 840 nW/$cm^2$ light intensity and a 7 mm diameter turbo light guide with 1100 nW/$cm^2$. Specimens were divided into three groups according to thickness of penetrating tooth (1 mm, 2 mm, 0 mm). Each group was further divided into four subgroups according to type of light guide and curing time (20 seconds, 40 seconds). Vickers' hardness was measured by using a microhardness tester. In 0 mm and 1 mm penetrating tooth group, which were polymerized by a turbo light guide for 40 seconds, showed the highest hardness values. The specimens from 2 mm penetrating tooth group, which were polymerized for 20 seconds, demonstrated the lowest hardness regardless of the types of light guides (p < 0.05). The results of this study suggest that, when projecting tooth material over a specified thickness, the increase of polymerization will be limited even if light intensity or curing time is increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.1030-1037
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• 2010

A fresh juice has become a new functional food available for dieting and health. However, the shelf-life of vegetable juice is very short because of the absence of heat pasteurization process. To elongate the shelf-life of vegetable juices, such as Angelica keiskei and Brassica loeracea var. acephala, the changes of microbiological, chemical and sensory property by UV irradiation were investigated. The total aerobic bacterial numbers of A. keiskei and B. loeracea var. acephala vegetable juices were $3.2{\times}10^5$ and $7.0{\times}10^4\;CFU/mL$, respectively, after wring process. However, the numbers were $3.6{\times}10^3{\sim}9.7{\times}10^3$ and $3.7{\times}10^3{\sim}2.7{\times}10^4\;CFU/mL$ after UV treatment on wring juice, and this lower microbial number was maintained during storage. The number of coliform bacteria also reduced significantly by UV treatment, and the bactericidal effect was higher when the flow rate is slower. The increase of lightness and yellowness, and decrease of redness were observed after treatment of UV on both vegetable juices, but the differences were not significant between flow rates. The ascorbic acid contents of vegetable juices were reduced by UV irradiation regardless of flow rate, and storage. Overall acceptance in sensory analysis revealed that there was no significant difference between the control and vegetable juice irradiated UV at 0 days, but sample with UV treatment showed higher score at 3 days. Therefore, UV treatment on vegetable juice can elongate the shelf-life without any problems in flavor and color.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1312-1317
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• 2008

Physicochemical changes were investigated for the shelf-life extension of cultured wild-ginseng roots during storage with various pre-treatments with blanching, CAMICA-SD and DF-100 and treatments with citric acid and vitamin C. The pH of cultured wild-ginseng roots showed the range of $6.06{\sim}6.42$ at $10^{\circ}C$, but showed higher ranges of $6.08{\sim}6.91$ and $6.08{\sim}8.68$ at 20 and $30^{\circ}C$, respectively. Browning index (a/b) was increased with increasing storage temperature, and the index at 10 and $30^{\circ}C$ were 0.405 and 0.469 after 2 weeks, respectively. Browning index and viable cell number of CAMICA-SD pre-treatment showed little changes compared to pre-teatment with blanching or DF-100. When the cultured wild-ginseng roots were treated with 1.0% citric acid and 0.2% DF-100 after pre-treatments with CAMICA-SD, viable cell number was slightly increased to $4.9{\times}10^2CFU/g$ for 3 weeks storage at $10^{\circ}C$. The mixture of citric acid and DF-100 was also used to prevent the growth of microbiology and to reduce browning reaction, especially enzymatic browning reaction. The mixture might effectively extend shelf life of the cultured wild-ginseng roots.