• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.155-162
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• 1989

This experiment was conducted to investigate the endosperm characteristics of an opaque rice which was derived from an Indica cultivar Pokhareli Mashino. Grain apperance of opaque rice looked similar to the waxy grain, while the blue-color response to the iodine solution was similar to non-waxy endosperm. The shape of starch granules was alike each other, but their size were different each other with the smallest of the opaque rice. Their cristaline structure of starch granules were A type. The content of total protein and most of the amino-acids of opaque rice was about 1.5 times of other varieties. Alkali digestibility of the opaque rice was very low. Total water uptake and hydration rate of opaque rice was similar to non-waxy variety Tongil. Amylogram characteristics such as viscosity, setback and consistency of opaque rice revealed medium value between. waxy and non-waxy rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.5 no.1
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• pp.57-64
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• 1969

Several field and sweet corn varietiea from several sources were crossed with a variety carrying the opaque-2 gene to determine the phenotypic interactions in the breeding of high lysine maize. Although opaque-2 lines showed lower protein content than the corresponding normal varieties, there was no correlation between the protein levels of the two types. opaque-2 maize contained more lysine, but no relationship was found between the protein content and the lysine content of either normal or opaque-2 types, suggesting that high lysine corn using the opaque-2 gene may be developed independently from the protein content. The F2 segregation ratios for normal and opaque-2, 100-kernel weights, percentage seed set, opaque-2 phenotype, disease susceptibility, and the relationship between protein and lysine content of normal and opaque-2 were investigated. The determinations and observations were made on the F2, F3, and BC1 Lysine content was determined by the ion exchangeresin combined with paper chromatography method. Most crosses segregated in a 1-opaque-2 : 3-normal ratio as expected. Opaque-2 segregates were lighter than the normal type and smaller in size. A mottled phenotype of opaque-2 maize observed in the Philippines yellow endersperm. In some varieties opaque-2 maize was very susceptible to the ear and kernel rot disease. No. 5(female) and opaque-2(male). Selectlon of a double mutant of waxy and opaque-2 by using the iodine technique and electric lamp was discussed. opaque-2 and floruy-2 were not allels. Different percentage of seed set were observed in the segregation of aewx crossed with opaque-2. An unusual gametophytie relationship was involved in a cross between Glutinous.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.1
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• pp.144-164
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• 1997

The purpose of this study were to investigate the chemical composition, mean particle size, linear thermal expansion coefficient and metal-bonding strength of the regular opaque powder and core powder. In this study, 4 types of ceramic powders, namely Duceram Jacket Opaque powder, Duceram Opaque powder, Vita Hi-Ceram powder, Vita VMK Paint On-88 powder were used. Chemical composition was evaluated by EDS(Energy Dispersive X-ray Spectrophotometer, Oxford QX-2000, England), particle size was measured by MALVERN Instruments(MALVERN Instruments SB. OC., U.S.A.. ad linear thermal expansion coefficient was measured by dilatometer(Motoyama, Japan). Bond strength was measured by the Universal tsting machine(Istron Co., Ltd., U.S.A.). The Results were as follows : 1. Through recognition of the relative difference in chemical composition between the core powder and the regular opaque powder, the difference in the proportion of $Al_2O_3$ in each type of material is demonstrated ; Duceram Jaket Opaque powder : 30.16%, Duceram Opaque powder : 16.60%, Vita Hi-Ceram : 63.64%, Vita VMK Paint-On 88 : 16.16%. 2. There was no significant difference in the proportion of metal-bonding materials between the core powder and the regular opaque powder. 3. In the regular opaque powder, alkaline materials were incoporated in order to increase the coefficient of thermal expansion. 4. In the particle size analysis, there was no significant difference in mean particle size or in the particle size distribution between the core powder and the regular opaque powder. 5. In the thermal expansion test for temperature range of $25-600^{\circ}C$, the regular opaque powder had higher coefficient of thermal expansion than that of core powder. 6. In the 4 point flexural bending test, there was no statistically significant difference in the mean bond strength between the core powder and the opaque powder among the Duceram products.

• The Journal of the Korean dental association
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• v.49 no.4
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• pp.203-210
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• 2011

The aims of this study were to evaluate the adequate thickness of opaque resins for situations such as an oral black cavity and discolored tooth structure, as well as the translucency of each opaque material at various thicknesses. Six opaque-shade composite resins (Z-350 OA3, Amelogen Universal A2O, Esthet-X A2O, Esthet-X A4O, Charmfil UO and Aelite Universal OA3) were prepared in metal molds with a hole of 8 mm in diameter and various thicknesses (0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0 mm and 4.0mm). Four backgrounds (white tile, black tile, C4 shade porcelain and opaque resin itself) were used to determine the translucency parameter (between black and white backgrounds). and to mimic a black oral cavity (between black and opaque resin backgrounds) and a discolored tooth structure (between C4 and opaque resin backgrounds). Color measurements were made by a colorimeter to determine the CIELAB values of each specimen with each background and to calculate the translucency parameter and ${\Delta}E^*$ value difference among the specimens on the backgrounds. The translucency parameter and ${\Delta}E^*$ obtained between black and opaque resin backgrounds decreased in similar pattern as thickness increased. A C4 background was masked by resin thicknesses of 0.5-1.0mm, while a black background required thicknesses of 1.0-2.0mm. Adequate knowledge about differences in the optical character like translucency of the materials used is essential, together with the accumulated experience of the individual clinician.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.356-364
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• 2007

The purpose of this study was to assess the background color-interceptive ability ana opacity of opaque shade composites (Universal composite, Filtek Z350, Charisma, Clearfil ST, Palpaque Estelite, Esthet-X, and Metafil Flo). Twenty four background specimens (diameter 5.5 mm, thickness 3.0 mm) with Root dentin Mustard (Bisco, Schaumburg, IL, USA) were made. The CIE $L^*a^*b^*$ value of background specimens was measured by a spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland). Three specimens in every group were filled on the background specimens. The surface color of samples was measured by a spectrophotometer in 3.0 mm and every thickness to 0.5 mm while grinding. The color difference in the background color along with 3.0 mm specimen gauged the masking effect in each thickness while grinding and polishing. The opacity was calculated in 1 mm thick specimens. The opacity was in the decreasing order of Clearfil ST, Metafil Flo, Filtek Z350, Palpaque Estelite, Universal composite, Charisma, and Esthet-X (p < 0.05). As the thickness get reduced, $L^*$ value showed decreasing, $a^*$ increasing tendency. The surface color difference between pair of the 3.0 mm thick specimen and after grinding in same opaque resin was above 3.3 except Clearfil ST and Metafil Flo. The color difference (${\Delta}E^*$) between pair of background specimen and opaque resin built-up specimen showed more than 10.0 regardless kinds and thickness. The variance in opacity characteristics and color of the opaque composites is dependent upon manufacturer. When using the opaque resin, the optical properties of each material must be considered as well as cavity.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.2
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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.

• Journal of the Korean Society of Visualization
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• v.3 no.1
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• pp.20-25
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• 2005

An x-ray PIV (Particle Image Velocimetry) technique was developed fur measuring quantitative information on flows inside opaque conduits and/or opaque-fluid flows. To check the performance of the x-ray PIV technique developed, it was applied to a liquid flow in an opaque Teflon tube. To acquire x-ray images suitable for PIV velocity field measurements, the refraction-based edge enhancement mechanism was employed with seeding detectable tracer particles. The amassed velocity field data obtained were in a reasonable agreement with the theoretical prediction. The x-ray PIV technique was also applied to get velocity fields of blood flow and to measure size and velocity of micro-bubbles simultaneously, and to visualize the water refilling process in bamboo leaves. The x-ray PIV was found to be a powerful transmission-type flow imaging technique fur measuring quantitative information of flows inside opaque objects and various opaque-fluid flows.

• Journal of Technologic Dentistry
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• v.22 no.1
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• pp.39-47
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• 2000

This study is the know the difference bond strength according to painting method of Opaque porcelain. Among Porcelain powder for Porcelain, Noritake powder, Bonding agent 1 class and metal are selected as Base metal alloy. And painting method of Opaque porcelain is divided by 4 groups : PG, WG, NG and DG. Also it is to manufacture 24 sheets of Specimen by 6 each every method and to measure Crack-initiation Strength of Metal-porcelain and it is to observe it by Scanning electron microscope. I come to get a conclusion as follows. 1. As for Debonding strength of every experiment groups, it showed that WS group which executed Wash bake had highest value, 44.25MPa and NG group which used Normal powder had value, 42.11MPa and DG group which used Bonding agent had value, 35.88MPa and PG group which used Paste opaque had value, 35.39MPa. 2. In four painting methods of Opaque porcelain, PG group, WG group, NG group and DG group, there is no significant difference statistically in Crack-initiation Strength. 3. As a result of observing fracture surface with Scanning electron microscope, it was showde that PG group remained a lot of particle of porcelain on the surface of metal than WG group, NG group and DG group.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.16-19
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• 1977

Feeding test was conducted to determine the values of opaque-2 corn selected from opaque-2 conversion program at the Crop Experiment Station, Suwon. At the end of 24 days of experiment, the average gain of body weight of white rats fed on opaque-2 corn was 40.2 grams, that of the rats on normal corn, 31.4 grams, 1.3 fold difference. The growth rate of rats expressed by regression coefficients indicated that the effects of opaque-2 corn was greater than that of normal corn.

• Journal of Technologic Dentistry
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• v.23 no.2
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• pp.211-221
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• 2002

The purpose of this study was to analyze the commercial paste opaque products currently available in domestic of foreign as well as domestic, such as Duceram Plus(DU; Ducera Dental GmbH, Germany), VMK 95(VM; Vita Co., Germany), Noritake EX-3(EX; Noritake Co., Japan) and Ceramax(CE; Alphadent Co., Korea). They were characterized in thermal expansion coefficient, particle size distribution, viscosity and solvent using thermomechanical analyzer, particle size analyzer, rheometer and infrared spectrophotometer. Experimental results are as follows; Firstly, thermal expansion coefficients were determined $13.9{\times}10-6/^{\circ}C$ for DU, $14.3{\times}10-6/^{\circ}C$ for VM, $13.3{\times}10-6/^{\circ}C$ for EX, and $14.0{\times}10-6/^{\circ}C$ for CE. Secondly, percent of partice size below $1{\mu}m$ were 12% for DU, VM and CE, and 13% for EX, percent between $1{\mu}m$ and $5{\mu}m$ were 42% for DU, 42% for VM, 38% for EX, and 61 % for CE, percent between $5{\mu}m$ and $10{\mu}m$ were 21 % for DU, 24% for VM, 20% for EX, and 18% for CE, and over $10{\mu}m$ were 25% for DU, 22% for VM, 29% for EX, 9% for CE. Thirdly, the basic composition of the solvent in all of the commercial paste opaques were determined as ethylene glycol from FT-IR investigation. Lastly, measured viscosities were 1798 cp for DU, 536 cp for VM, 1110 cp for EX, and 721 cp for CE.