• The Journal of Korean Academy of Prosthodontics
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• v.45 no.6
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• pp.724-734
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• 2007

Statement of problem. Translucency and masking effect of provisional crown and fixed partial denture materials is an important esthetic consideration. But, provisional resin materials differ substantially in their ability to mask underlying colors. Purpose. The purpose of this study was to evaluate the translucency differences of provisional resin materials at various thicknesses and the correlation between the translucency and the masking efficiency. Material and methods. Two polymethyl methacrylate resins (Jet Tooth Shade, Alike) and three resin composites (Protemp 3 Garant, Luxatemp and Revotek LC) were used. Specimens (n=6) were fabricated from each material in 0.3, 0.5, 0.8, 1.0, 1.5, 2.0 and 3.0 mm thickness. The CIELAB parameters of each specimens were measured using a spectrophotometer. The translucency parameter (TP) values and the masking effect $({\Delta}ME^*{_{ab}})$ values were computed and all data were statistically analyzed by one-way ANOVA and the multiple comparisons Scheffe test. The correlation between the thickness and the TP values and the correlation between the thickness and the ${\Delta}ME^*{_{ab}}$ values were also evaluated by correlation analysis and regression analysis. Results. The TP values and the ${\Delta}ME^*{_{ab}}$ values were significantly related to the thickness in all specimens. The TP values were more sensitive to the change of thickness than the ${\Delta}ME^*{_{ab}}$ values. The order of the translucency by brand was different from the order of the masking effect by brand in all thickness groups. Conclusion. Within the limitations of this study, the translucency and masking effect of the provisional resin materials investigated were significantly related to their thickness. The masking effect of provisional resin was correlated with the translucency parameter, but the order of the masking effect by brand was different from the order of the translucency parameter.

• Korean Institute of Interior Design Journal
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• v.25 no.2
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• pp.70-82
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• 2016

The playgrounds installed in the city try a variety of changes in play equipment more than traditional playgrounds, these playgrounds with formal rides are still different from nature friendly playground. For this reason, when in 2014 the department of environment pushed forward 'Aitteulag' project constructing ecological playground, the department aimed to provide the natural ecological spaces that are insufficient in the city and act as play space for children, leisure and community space for residents. Therefore, after inspecting 10 ecological playgrounds in Europe and Japan, in this study we suggested the construction guidelines of ideal ecological playground by comparing and analyzing these cases. We checked the environment-friendliness of these playgrounds in the 2 fields (playground component, ecological program) based on the ecological playground guidelines presented by the ministry of environment. The playground components are classified as siting location, spatial configurations, natural elements, play area, amusement facilities, play materials, open spaces, additional facilities. The ecological programs are divided into habitat, species, natural material, five senses. The following is the summary of the results about the reflection of eco-friendly planning factors. In terms of "habitat": bush and shade wood were highest at 95%. In terms of "species": local indigene(100%) and habitat for insects(95%) were higher than others. In terms of "natural material": wood(61.1%) was the highest. In terms of "details of wood(61.1%)": wood fence (95%), exploring wood and using sticks(85%) were higher than others. In terms of "five senses": hearing (32.1%), tactile(26.4%), and visual(23.9%) were in order. Therefore, on the basis of these results, this study proposed the planning factors that should be considered and complemented more in the construction of domestic urban ecological playground in future.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.71-77
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• 2000

The color of an esthetic restorative material is controlled primarily by thickness of the material and background color. Although the effects of the two factors on the color coordinates of esthetic dental materials have been reported, the mechanism has not been clarified well enough to explain the effects quantitatively. The purpose of this study was to evaluate the effect of thickness and background color on the color of tooth colored restorative materials quantitatively. One hundred sixty samples were fabricated from two commercial light-cured composite resins and two commercial compomers. The color characteristics and changes in the color coordinates were measured by a tristimulus colorimeter (Model TC-6FX, Tokyo Denshoku Co. Japan) using the CIELAB system. The results were as follows: 1. As thickness increased from 1.0 to 4.0mm, values of $L^*$ $a^*$ $b^*$ changed irregulary for white and dentin color background, but showed no obvious difference in color for black background. 2. The colors of composite resins and compomers were significantly influenced by background color. 3. The color difference was recognized even the same shade name in four representative kinds of composite resins and compomers. 4. As thickness changed, values of color difference for same products and same background color showed constancy, but showed difference for different background color.

• Fashion & Textile Research Journal
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• v.24 no.6
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• pp.801-811
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• 2022

In this study, we constructed a database of dyeing concentrations of all reactive dyes used for dyeing linen according to the thickness of the linen fabric and attempted to improve the reproducibility of the dyeing process for the commercialization of linen fabric materials. Linen fabric is a natural cellulose material that is comfortable and suitable for eco-friendly trends. It is a typical summer material with excellent breathability and thermal conductivity, quick moisture absorption and dissipation, and a cool touch. Dyeability and fastness were evaluated depending on the thickness of the linen fabric using a monochlorotriazine (MCT) reactive dye and bifunctional yellow, red, and blue dyes. All three colors of the MCT reactive dye and bifunctional dyes exhibited a darker shade as the fiber thickness of the marker increased. Fastness to washing was excellent at grades 4-5 or higher, regardless of the color of the dye and the number of linen fabrics. Although some color-fastness differences were noted, with the color change occurring most frequently with blue color, the fastness variations with dye type were mostly similar. The results of this study are expected to facilitate the selection of reactive dyes according to the thickness of the linen fabric based on the basic data from the laboratory, which will aid in the mass production of linen fabric and benefit the fashion industry.

• The Journal of Advanced Prosthodontics
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• v.16 no.4
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• pp.231-243
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• 2024

PURPOSE. The objective of the study was to analyze the impact of cement, bonding pretreatment, and ceramic abutment material on the overall color results of CAD-CAM ceramic crowns bonded to titanium-based hybrid abutments. MATERIALS AND METHODS. For single implant restoration of a maxillary lateral incisor a total of 51 CAD-CAM-fabricated monolithic lithium disilicate crowns were fabricated and subsequently bonded onto 24 lithium disilicate Ti-base abutments, 24 zirconia Ti-base abutments and 3 resin abutment replicas as a control group. The 48 copings were cemented with three definitive and one provisional cement on both grit-blasted and non-blasted Ti-bases. The color of each restoration and surrounding artificial gingiva was measured spectrophotometrically at predefined measuring points and the CIELAB (ΔE_ab) color scale values were recorded. RESULTS. The color outcome of ceramic crowns bonded to hybrid abutments and soft tissues was affected differently by cements of different brands. Grit-blasting of Ti-bases prior to cementing CAD-CAM copings affected the color results of allceramic crowns. There was a significant difference (P = .038) for the median ΔE value between blasted and non-blasted reconstructions at the cervical aspect of the crown. Full-ceramic crowns on zirconia Ti-base abutments exhibited significantly lower ΔE values below the threshold of visibility (ΔE 1.8). In all subcategories tested, the use of a highly opaque temporary cement demonstrated the lowest median ΔE for both the crown and the artificial gingiva. CONCLUSION. Various cements, core ceramic materials and airborne particle abrasion prior to bonding can adversely affect the color of Ti-base supported ceramic crowns and peri-implant soft tissue. However, zirconia CAD-CAM copings and an opaque cement can effectively mask this darkening.

• Korean Journal of Materials Research
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• v.25 no.4
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• pp.196-201
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• 2015

This paper presents the impact of partial shading on $CuIn_xGa_{(1-x)}Se_2(CIGS)$ photovoltaic(PV) modules with bypass diodes. When the CIGS PV modules were partially shaded, the modules were under conditions of partial reverse bias. We investigated the characterization of the bypass diode and solar cell properties of the CIGS PV modules when these was partially shaded, comparing the results with those for a crystalline silicon module. In crystalline silicon modules, the bypass diode was operated at a partial shade modules of 1.67 % shading. This protected the crystalline silicon module from hot spot damage. In CIGS thin film modules, on the other hand, the bypass diode was not operated before 20 % shading. This caused damage because of hotspots, which occurred as wormlike defects in the CIGS thin film module. Moreover, the bypass diode adapted to the CIGS thin film module was operated fully at 60% shading, while the CIGS thin film module was not operated under these conditions. It is known that the bypass diode adapted to the CIGS thin film module operated more slowly than that of the crystalline silicon module; this bypass diode also failed to protect the module from damage. This was because of the reverse saturation current of the CIGS thin film, $1.99{\times}10^{-5}A/cm^2$, which was higher than that of crystalline silicon, $8.11{\times}10^{-7}A/cm^2$.

• Asian Journal of Turfgrass Science
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• v.18 no.1
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• pp.15-27
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• 2004

For the study of ecophysiological characteristics of ground cover plant with shade tolerance, the material productivity and the growh characteristics were analyzed in Hosta clausa community at experimental farm of Kemyung College from March to October. The installation of experimental plots were split into control plot (full sunlight), 30%, 50%, 70%, shading rate by completely randomized design method. After the transplant, to take into account the edge effect of plant population, the plants were selected from each plot by random sampling every 10days. The following results were obtained; Then number of leaf, length of leaf and width of leaf length of leafstack remarkably showed high tendency under 30%, 50% shading plot as compared with control, 70% shading plot for the exmination as the process of develpment. They showed characteristics as herbaceous ground with shade tolerance under conparatively low the light condition and they ettain a stabilized development.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1948-1953
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• 2014

This study examined changes in antioxidant activity as well as contents of rosmarinic acid, homoplantaginin, and luteolin, which is the main substance of Salvia plebeia R. Br. (SPR) known to have anti-inflammatory efficacy, according to drying, blanching, and fermentation conditions. Rosmarinic acid content was 16.42 mg/g upon hot-air drying and 10.19 mg/g upon hot-air drying after blanching, and there was no significant difference in the case of leaf and root freezing or cold-air drying. Rosmarinic acid content was 8.69 and 8.15 mg/g in the case of air-drying in the shade and freeze-drying, respectively, and decreased to 0.05 mg/g or undetected after fermentation. SPR processed by freeze-drying, cold-air drying in the shade, and hot-air drying showed ABTS radical scavenging ability over 98.5% at a concentration over $500{\mu}g/mL$ as well as excellent radical scavenging ability of 87.3% in the case of hot-air drying after blanching. Root showed lower ABTS radical scavenging ability than leaves. SOD-like activity was measured to be 6.1~27.8% at a concentration of $1,000{\mu}g/mL$, which was significantly difference from ABTS radical scavenging ability. As rosmarinic acid and homoplantagine, an anti-inflammatory material contained in SPR, are almost undetectable after oxidation fermentation during processing, hot-air drying after blanching or drying seems to be suitable to develop SPR as a functional substance.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.2
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• pp.136-147
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• 2003

Statement of problem : Ceramic and composite resin have been used to fulfill the demand for esthetic prosthesis. However, ceramic is easy to break and wears off the opposite natural teeth. Conventional composite resin also has low abrasive resistance and color stability. Ceramic Optimized Polymer (ceromer) was developed in mid-1990s to overcome the shortfalls of ceramic and composite resin. Ceromer has similar abrasiveness with the natural tooth and has relatively high strength. Color stability affects esthetics and long-term prognosis of the prosthesis. Purpose The purpose of this study was to compare color stability of ceromers(2 types : $Artglass^{(R)}$. $Targis^{(R)}$) with ceramics ($Vintage^{(R)}$-polishing, $Vintage^{(R)}$-glazing). Material and Method : The color difference(${\Delta}E^*$) was measured by spectrophotometer with different immersion time. Twenty disks, 3mm in thickness and 10mm in diameter, were fabricated for each specimen in shade A2(Vita Lumin shade guide), Specimens (5 samples in each group) were immersed in the food colorants (Red no.3. Yellow no.4, Blue no.1, Distilled water) for 24 hours, 48 hours and 72 hours respectively. $L^*,\;a^*$ and $b^*$ value were measured with spectrophotometer (CM 503i : Minolta Co., Japan) and mean ${\Delta}E^*$ value was calculated for statistical analysis Results : The results of this study were obtained as follows. 1. The ${\Delta}E^*$ values of all test samples increased with the time of immersion. 2. The ${\Delta}E^*$ values of all materials increased in order of Distilled Water, Yellow no.4, Blue no.1 and fed no.3. There was significant difference between Red no.3 and the other food colorants(p<0.05). 3. The ${\Delta}E^*$ values increased in order of $Vintage^{(R)}$-glazing, $Vintage^{(R)}$-polishing. $Artglass^{(R)}$ and $Targis^{(R)}$. There was significant difference between $Vintage^{(R)}$-glazing and the other materials (p<0.05). Conclusion : By means of the above results, immersion time was found to be a critical factor for color stability of ceromer. For the long-term color stability of prosthesis it is recommended patients having ceromer prosthesis ($Artglass^{(R)},\;Targis^{(R)}$) to reduce the habitual intake of Red no.3 colorants con taming foods.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.358-373
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• 1997

Resin modified glass ionomers were introduced in 1988 to overcome the problems of moisture sensitivity and low early mechanical strength of conventional glass ionomers and to maintain their clinical advantages. The purpose of this study was to evaluate the color stability of four resin modified glass ionomers(Fuji II LC, Vitremer, Dyract and VariGlass), one resin composite material(Z-100), and one conventional glass ionomer(GC Fuji II) under several conditions. These conditions were as follows: 1) before curing, 2) after curing, 3) after polishing, 4) after 500 thermocycling, 5) after 1,000 thermocycling, 6) after 1,500 thermocycling and 7) after 2,000 thermocycling. Three specimens of each material/shade combination were made. Materials were condensed into metal mold with a diameter of 10 mm and a thickness of 2.0 mm, and were pressed between glass plates. The material was polymerized using a light polymerizing unit(Visilux II, 3M, USA). After removal of excess, the surface was polished sequentially on wet sandpapers. A reflection spectrophotometer(Model TC-6FX, Tokyo Denshoku Co., Japan) was used to determine CIELAB coordinates($L^*,a^*$ and $b^*$) of each specimen. CIE standard illumination C was used as the light source. The results were as follows : 1. In comparing different shades of same material, CIELAB color difference(${\Delta}E^*$) value was not significantly different from each other(p>0.05). 2. CIELAB color difference(${\Delta}E^*$) values between after-curing and after-polishing were ranged from 5.53 to 27.08. These values were higher than those of other condition combinations. 3. CIELAB color difference(${\Delta}E^*$) values between before-thermocycling and after-thermocycling were ranged from 1.40 to 7.81. Despite the number of thermocycling increased, CIELAB color difference(${\Delta}E^*$) value was low. 4. The color stability of resin modified glass ionomers was more stable than that of conventional glass ionomers but less stable than that of Z100.