• Title/Summary/Keyword: Light materials

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A STUDY OF THE SHEAR BOND STRENGTH OF COMPOSITE RESIN TO LIGHT-CURING GLASS IONOMER CEMENTS (광중합형 글라스아이오노머 시멘트와 복합레진과의 전단결합강도에 관한 연구)

  • Kim, Deok;Min, Byung-Soon
    • Restorative Dentistry and Endodontics
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    • v.19 no.2
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    • pp.447-459
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    • 1994
  • The purpose of this study is to evaluate of shear bond strength of light-curing composite resin to light-curing glass ionomer cement. Composite resin and glass ionomer cement have been widely used as an esthetic filling materials in dental clinics. To achieve better clinical results, sandwich technic was developed with conpensating for disadvantages of these two materials. Especially, light-curing glass ionomer cement provided greately improved bonding strength of teeth or composite resin, and then excellent clinical results can be acquired. In this study, 6 commercial light-curing glass ionomer cements(3 commercial restorative materials : Fuji II LC, Variglass VLC, Vitremer, and 3 commercial lining materials : Fuji Lining LC, Baseline VLC, Vitrebond) were devided two groups. According to manufacturer's appointment, no surface treatment was referred to N groups. Supposing. of clinical practice, surface grinding with water spray at 320 grit sand paper, 40 seconds etching with 37% phosphoric acid, 20 seconds washing, 20 seconds air drying was referred to N groups. Totally 12 experimental groups were devided, and all 120 specimens from 10 specimens of each groups were made. After light-curing composite resin was bonded to light-curing glass ionomer cement, shear bond strength was tested by Instron universal testing machine between glass ionomer cement and composit resin. The data were analyzed statistically by Student's t-test and ANOVA. The obtained results were as follows; 1. In light-curing glass ionomer cement, restorative materials showed higher shear bond strength to composite resin than lining materials(p<0.05). 2. Variglass VLC of restorative material group and Baseline VLC of lining material group have highest shear bond strength to composite resin(p<0.001). 3. In light-curing glass ionomer cement, surface grinding and acid etching reduced shear bond strength to composite resin(p<0.001)}. 4. VGN group 1s highest shear bond strength to composite resin, VBE group is lowest shear bond strength to composite resin(p<0.001).

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A Study on Fashion Design Applying Reflection of the Light (빛의 반사를 응용한 패션디자인 연구)

  • Lee, Yun-Jung;Kim, Yun-Hee
    • Journal of the Korea Fashion and Costume Design Association
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    • v.13 no.3
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    • pp.1-14
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    • 2011
  • A dress is commonly designed and worn as a work of art. It is developed through various ways to show the expression of our bodies with functional aspects. Light plays a role in everyday life functionally and aesthetically. We can use the light in many different ways in order to enhance the beauty of the designs. The purpose of this study is to suggest sensible designs with the active expression of light reflection. The designs are especially focused on utilizing light that shows the combination between natural human body's movement and reflection of the light. The use of reflective materials shows the character of movement when it exposes to light. The methods allow to amplify the aesthetic effects of the designs. Reflective materials were used in the resulting design to show the various effects of light by applying the movement which is artistic and aesthetic pleasing aspect for the clothing. The movement is accentuated when the wearer moves, or the air flows through the adding materials on the clothing. In addition, the beads attached to the end of the springs to show the movement of the light. The combination of the spring and the light movement resulted in a dazzling effect. I hope in the future, more studies will be conducted to further use of fiber optics and other innovative ways to use light in fashion.

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White-Light-Emitting Molecule

  • Park, Soo-Young;Park, Sang-Hyuk
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.481-481
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    • 2009
  • For a new generation of white light sources, we present the first example of a concentration-independent ultimate white-light-emitting molecule based on excited-state intramolecular proton transfer materials. Our molecule is composed of covalently linked blue- and orange-light-emitting moieties between which energy transfer is entirely frustrated, leading to the production of reproducible, stable white photo- and electroluminescence.

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A Short Review of Light Barrier Materials for Food and Beverage Packaging

  • Kwon, Seongyoung;Orsuwan, Aungkana;Bumbudsanpharoke, Nattinee;Yoon, ChanSuk;Choi, Jungwook;Ko, Seonghyuk
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.24 no.3
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    • pp.141-148
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    • 2018
  • Photo-oxidation is one of the main causes of food deterioration of great variety of foods, such as dairy products, nuts, meat products, and wine. It causes a loss of both nutritional value and sensorial quality of products and may even leads to the formation of toxic compounds. Active packaging for food and beverages has been investigated and developed with embedding light absorbers or blocking materials into the plastics. In recent years, several novel light barrier materials have been proposed as an alternative option for different applications. This article reviews the up-to-date technology in light absorber and blocking material with special emphasis on chemical compound and mechanism. Inorganic, organic, hybrid organic-inorganic, and natural light absorbers were scoped. The challenges and future perspectives of light barrier materials are also discussed.

An Analysis of Light Induced Degradation with Optical Source Properties in Boron-Doped P-Type Cz-Si Solar Cells (광원의 특성에 따른 Boron-doped p-type Cz-Si 태양전지의 광열화 현상 분석)

  • Kim, Soo Min;Bae, Soohyun;Kim, Young Do;Park, Sungeun;Kang, Yoonmook;Lee, Haeseok;Kim, Donghwan
    • Korean Journal of Materials Research
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    • v.24 no.6
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    • pp.305-309
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    • 2014
  • When sunlight irradiates a boron-doped p-type solar cell, the formation of BsO2i decreases the power-conversion efficiency in a phenomenon named light-induced degradation (LID). In this study, we used boron-doped p-type Cz-Si solar cells to monitor this degradation process in relation to irradiation wavelength, intensity and duration of the light source, and investigated the reliability of the LID effects, as well. When halogen light irradiated a substrate, the LID rate increased more rapidly than for irradiation with xenon light. For different intensities of halogen light (e.g., 1 SUN and 0.1 SUN), a lower-limit value of LID showed a similar trend in each case; however, the rate reached at the intensity of 0.1 SUN was three times slower than that at 1 SUN. Open-circuit voltage increased with increasing duration of irradiation because the defect-formation rate of LID was slow. Therefore, we suppose that sufficient time is needed to increase LID defects. After a recovery process to restore the initial value, the lower-limit open-circuit voltage exhibited during the re-degradation process showed a trend similar to that in the first degradation process. We suggest that the proportion of the LID in boron-doped p-type Cz-Si solar cells has high correlation with the normalized defect concentrations (NDC) of BsO2i. This can be calculated using the extracted minority-carrier diffusion-length with internal quantum efficiency (IQE) analysis.

Interlayer Engineering with Different Host Material Properties in Blue Phosphorescent Organic Light-Emitting Diodes

  • Lee, Jong-Hee;Lee, Jeong-Ik;Lee, Joo-Won;Chu, Hye-Yong
    • ETRI Journal
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    • v.33 no.1
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    • pp.32-38
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    • 2011
  • We investigated the light-emitting performances of blue phosphorescent organic light-emitting diodes, known as PHOLEDs, by incorporating an N,N'-dicarbazolyl-3,5-benzen interlayer between the hole transporting layer and emitting layer (EML). We found that the effects of the introduced interlayer for triplet exciton confinement and hole/electron balance in the EML were exceptionally dependent on the host materials: 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole, 9-(4-tert-butylphenyl)-3,6-ditrityl-9H-carbazole, and 4,4'-bis-triphenylsilanyl-biphenyl. When an appropriate interlayer and host material were combined, the peak external quantum efficiency was greatly enhanced by over 21 times from 0.79% to 17.1%. Studies on the recombination zone using a series of host materials were also conducted.

Luminescence Property of ZnS:Mn,Mg Phosphor with Excitation of Plasma Blue Light Source

  • Ryu, Si Hong;Kim, Wan Kyu;Lee, Seong Eui
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.1
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    • pp.24-27
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    • 2013
  • In this paper, we investigated the effect of luminescence properties of various concentrations of magnesium-doped ZnS:Mn phosphor excited by plasma luminescence device. The PL intensity was evaluated in the range of 300~500 nm excitation wavelengths. We found the highest PL intensity of the phosphors excited by 365 nm and 450 nm was observed at Mg concentrations of 1.4 wt% and 0.8 wt%, respectively. In addition, an emission peak was distinguished at 580 nm wavelength. With increasing Mg dopant level, enhanced PL intensity was observed, which is possibly applicable to color converting materials by blue emission for white light sources. Finally, we evaluated the luminance properties of color converting ZnS:Mn,Mg phosphors with plasma blue light source. the white luminance of plasma light source with CIE(0.36,0.26) was established by color converting phosphors of ZnS:Mn with 0.8 wt% Mg.

A Cyan Fluorescent Protein Gene (cfp)-Transgenic Marine Medaka Oryzias dancena with Potential Ornamental Applications

  • Vu, Nguyen Thanh;Cho, Young Sun;Lee, Sang Yoon;Kim, Dong Soo;Nam, Yoon Kwon
    • Fisheries and Aquatic Sciences
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    • v.17 no.4
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    • pp.479-486
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    • 2014
  • To evaluate their potential utility as an ornamental organism, novel transgenic marine medaka Oryzias dancena strains with a highly vivid fluorescent phenotype were established through transgenesis of a cyan fluorescent protein gene (cfp) driven by the endogenous fast skeletal myosin light chain 2 gene (mlc2f) promoter. The transgenic marine medaka strains possessed multiple copies of transgene integrants and passed their fluorescent transgenes successfully to subsequent generations. Transgenic expression in skeletal muscles at both the mRNA and phenotypic levels was, overall, dependent upon transgene copy numbers. In the external phenotype, an authentic fluorescent color was dominant in the skeletal muscles of the transgenic fish and clearly visible to the unaided eye. The phenotypic fluorescent color presented differentially in response to different light-irradiation sources; the transgenics displayed a yellow-green color under normal daylight or white room light conditions, a strong green-glowing fluorescence under ultraviolet light, and a cyan-like fluorescence under blue light from a light-emitting diode.

Highly transparent Pt ohmic contact to InGaN/GaN blue light-emitting diodes

  • Chul Huh;Kim, Hyun-Soo;Kim, Sang-Woo;Lee, Ji-Myon;Kim, Dong-Joon;Kim, Hyun-Min;Park, Seon-Ju
    • Journal of Korean Vacuum Science & Technology
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    • v.4 no.2
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    • pp.47-49
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    • 2000
  • We report on the fabrication and characterization of InGaN/GaN multiple quantum well light emitting diode (LED) with a highly transparent Pt ohmic contact as a current spreading layer. The value of light transmittance of a Pt thin film with a thickness of 8 m on p-GaN was measured to be 85% at 450nm. The peak wavelength and the full-width at half-maximum (FWHM) of the emission spectrum of the LED at 20 mA were 453 m and 23 m, respectively. Pt-contacted LEDs show good electrical properties and high light-output efficiency compared to Ni/Au-contacted ones. These results suggest that a Pt thin film can be used as an effective current spreading layer with high light-transparency.

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Highly transparent Pt ohmic contact to InGaN / GaN blue light - emitting diodes

  • Huh, Chul;Kim, Hyun-Soo;Kim, Sang-Woo;Lee, Ji-Myon;Kim, Dong-Joon;Kim, Hyun-Min;Park, Seong-Ju
    • Journal of Korean Vacuum Science & Technology
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    • v.4 no.3
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    • pp.78-80
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    • 2000
  • We reprot on the fabrication and characterization of InGaN/GaN multiple quantum well light-emitting diode (LED) with a highly transparent Pt ohmic contact as a current spreading layer. The value of light transmittance of a Pt thin film with a thickness of 8 nm on-GaN was measured to be 85% at 450 nm. The peak wavelength and the full-width at half-maximum (FWHM) of the emission spectrum of the LED at 20 mA were 453 nm and 23 nm, respectively. Pt-contacted LEDs show good electrical properties and high light-output efficiency compared to Ni/Au-contacted ones. These results suggest that a Pt thin film can be used as an effective current spreading layer with high light-transparency.

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