• Journal of the Korean institute of surface engineering
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• v.50 no.3
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• pp.206-211
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• 2017

$BiNbO_4:RE^{3+}$ (RE = Dy, Eu, Sm, Tb) phosphors were prepared by solid-state reaction at $1100^{\circ}C$ and their structural, photoluminescent, and morphological properties were investigated. XRD patterns exhibited that all the synthesized phosphors exhibited a triclinic system with a dominant (210) diffraction peak, irrespective of the type of activator ions. The surface morphologies of rare-earth-ion-doped $BiNbO_4$ phosphors were found to depend strongly on the type of activator ions. The $Eu^{3+}$ and $Dy^{3+}$ doped $BiNbO_4$ phosphors revealed a strong red (613 nm) emission resulting from the $^5D_0{\rightarrow}^7F_2$ transition of $Eu^{3+}$ and a dominant yellow (575 nm) emission originating from the $^4F_{9/2}{\rightarrow}^6H_{13/2}$ transition of $Dy^{3+}$ respectively, which were the electric dipole transitions, indicating that the activator ions occupy sites of non-inversion symmetry in the $BiNbO_4$ phosphor. The main reddish-orange emission spectra of $Sm^{3+}$-doped $BiNbO_4$ phosphors were due to the $^4G_{5/2}{\rightarrow}^6H_{7/2}$ (607 nm) magnetic dipole transition, indicating that the $Sm^{3+}$ ions were located at inversion symmetry sites in the $BiNbO_4$ host lattice. As for $Tb^{3+}$-doped phosphors, green emission was obtained under excitation at 353 nm and its CIE chromaticity coordinates were (0.274, 0.376). These results suggest that multicolor emission can be achieved by changing the type of activator ions incorporated into the $BiNbO_4$ host crystal.

• Advances in materials Research
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• v.3 no.4
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• pp.227-232
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• 2014

$Ce^{4+}$, $Eu^{3+}$, $Tb^{3+}$ co-doped $Ca_3Si_3O_8F_2$ phosphor was synthesized via solid state reaction method using $CaF_2$, $CaCO_3$ and $SiO_2$ as raw materials for the host and $Eu_2O_3$, $CeO_2$, and $Tb_4O_7$ as activators. The luminescent properties of the phosphor was analysed by spectrofluorophotometer at room temperature. The effect of excitation wavelengths on the luminescent properties of the phosphor i.e. under near-ultraviolet (nUV) and visible excitations was investigated. The emission peaks of $Ce^{4+}$, $Eu^{3+}$, $Tb^{3+}$ co-doped $Ca_3Si_3O_8F_2$ phosphor lays at 480(blue band), 550(green band) and 611nm (red band) under 380nm excitation wavelength, attributed to the $Ce^{4+}$ ion, $Tb^{3+}$ ion and $Eu^{3+}$ ions respectively. The results reveal that the phosphor emits white light upon nUV (380nm) / visible (465nm) illumination, and a red light upon 395nm / 535nm illumination. RE ions doped $Ca_3Si_3O_8F_2$ is a promising white light phosphor for LEDs. The emission colours can be seen using Commission international de l'eclairage (CIE) co-ordinates. A single host phosphor emitting different colours under different excitations indicates that it is a potential phosphor having applications in many fields.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.1
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• pp.20-25
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• 2015

Purpose: This study was evaluated the shade of feldspathic porcelain with various concentration of silver ion. Materials and Methods: The control group was conventional feldspathic porcelain with no silver ion, the experimental groups were the feldpathic porcelain with 5%, 10%, 20%, 30% silver ion. The number of specimens on the each group was 5. Commission Internationale de I'Eclairage (CIE) $L^*a^*b^*$ parameters were recorded twice for each specimen with a spectrophotometer (Model CM-2600d, Minolta, Japan). One-way Anova was used for statistical analysis. Results: L value was similar. a value was increasing and b value was decreasing with silver ion statistically significantly. ${\Delta}E$ was increasing according to silver ion significantly. Conclusion: The shade of feldspahtic porcelain was influenced by silver ion. Ag ion under 10% concentration is acceptable clinically.

• Food Science of Animal Resources
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• v.35 no.4
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• pp.449-458
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• 2015

The effects of quality grade and storage time on physicochemical, sensory properties and microbial population of Hanwoo striploin beef were investigated. After a total of 30 Hanwoo beef were slaughtered, the cold carcasses were graded by official meat grader at 24 h postmortem. The carcasses were categorized into five groups (quality grade 1++, 1+, 1, 2, and 3) and were vacuum-packaged and stored. The samples were kept for 1, 4, 6, 8, 11, 13, 15, 18, 20, 22 and 25 d for analyses. As the quality grade was increased, moisture, protein and ash contents decreased (p<0.05). Higher quality grade corresponded with higher fat contents. The shear force values decreased with increasing quality grade and showed decreases sharply during the first 4 d (p<0.05). pH, water holding capacity, cooking loss, and volatile basic nitrogen for grade 1++ groups were lower than for grade 3 (p<0.05). CIE L* and b* values increased as increased quality grade (p<0.05). Meat color decreased until 13 d and fluctuated after 15 d of storage (p<0.05). Regarding the sensory scores, higher quality grade corresponded with higher juiciness, tenderness, flavor, fatty and palatability scores (p<0.05). Generally, increased storage time for 15 d improved sensory scores attributes. Results indicate that a high quality grade could positively influence physicochemical and sensory properties.

• The Journal of Internal Korean Medicine
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• v.36 no.3
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• pp.348-360
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• 2015

Objectives From observing the tongue of a patient, one can assess the health status; this method has been frequently used in traditional Korean Medicine (KM) clinics. In particular, KM posits that the color of the tongue is highly related to digestive functions. In this study, the color of tongue and heart rate variability (HRV) were compared between chronic dyspepsia (CD) patients and healthy subjects. Methods Healthy subjects and CD patients with functional dyspepsia (FD), gastroesophageal reflux disease (GERD), or chronic gastritis (CG) were enrolled for the study. Profile view images of the tongue were acquired by using a computerized tongue image acquisition system (CTIS). The color of the tongue body was extracted from the non-coated region on the tongue images. Results Color differences in CIE L*a*b* color space between the three sub-types of CD patients and healthy subjects were analyzed by using multiple linear regression analysis with age and sex as the factors. The variable b* was significantly lower in GERD patients than in the controls (p=0.017). Variable a* was significantly lower in CG than in the controls (p=0.03). No significant difference was seen between FD and controls. In GERD, the tongue body seems to be intense red in color; in CG, pale red. Frequency domain analysis showed that HF was significantly lower in GERD patients than in the controls (p=0.041). Conclusions The color of the tongue body and HF of HRV can be used for diagnosing digestive functions in health care.

• Journal of Animal Science and Technology
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• v.57 no.7
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• pp.24.1-24.5
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• 2015

The objective of this study was to investigate the physicochemical and microbial quality of loin (m. longissimus dorsi) and top round (m. Semimembranosus) in Holstein veal produced from two slaughter age groups (5 and 8 months of age). A total of 20 Holstein calves were randomly selected from a local cattle farm. The slaughtered cold carcasses were vacuum-packaged. The samples were analyzed for proximate composition and physicochemical analyses and stored for 1, 7, 10, 20 and 30 days for microbiological analyses. Fat and protein contents of loin for the 8 month group were higher than those for the 5 month groups (p < 0.05). For both loin and top round muscles, the pH, cooking loss and the shear force values for the 5 month group was higher than those for the 8 month group (p < 0.05). On the other hands, the water-holding capacity (WHC) for the 8 month group was higher than those for the 5 month group (p < 0.05). In terms of meat color, CIE $L^*$ (lightness) for both muscle were higher in the 5 month group than in the 8 month groups. On the other hands, $a^*$ (redness) were higher in the 8 month group than in the 5 month groups (p < 0.05). Total aerobic counts in all samples remained up to 30 days at values less than 7 log CFU/g. However, there was no significant difference for both muscles between the two age groups. The results indicate that Holstein muscles from the 8 month group had desirable quality properties than those from the 5 month group.

• The Journal of Advanced Prosthodontics
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• v.12 no.3
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• pp.150-156
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• 2020

PURPOSE. The aim of this study was to evaluate the effect of different surface finishing processes on the color stabilities of lithium disilicate glass-ceramics, zirconia-reinforced lithium silicate ceramics, and resin nanoceramics after artificial ageing. MATERIALS AND METHODS. 216 samples were prepared from 3 different CAD/CAM materials (LAVA Ultimate, IPS e.max CAD, VITA Suprinity) with A1 HT color at a size of 14 × 12 mm and a thickness of 0.5 ± 0.05 mm. Color measurements of the samples were performed with a spectrophotometer using color parameters and CIE Lab color system on a gray backing between baseline color and after 5000 cycles of artificial ageing in 4 stages (i.e. the first measurement before the treatment, the second measurement after polishing, the third measurement after cement application, and the fourth measurement after artificial ageing). The results were evaluated using the Variance analysis and Fisher's LSD test. RESULTS. Resin nanoceramics (LU) exhibited higher color change values than zirconia-reinforced lithium silicate (VS) and lithium disilicate (EC) ceramics after artificial ageing. Manual polishing and glazing resulted in similar color change for LU and VS (P>.05). In the EC group, glazing provided statistically different results as compared to the manual polishing and control groups (P<.05). Among the ceramic groups, color change values of the subgroup, which was treated by glazing, of the zirconia-reinforced lithium silicate (VS) and lithium disilicate (EC) samples were below the clinically acceptable level (ΔE < 3.5). CONCLUSION. The lowest color change for all stages was observed in Vita Suprinity.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.18-29
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• 2015

The purposes of this research and development are as follows: first, to provide pleasant driving environments inside tunnels; second, to improve the current illumination environments lacking in diffusion luminance meters to meet tunnel lighting standards; and, third, to reduce the consumption of tunnel lighting energy accounting for approximately 65% of tunnel maintenance costs because of inadequate visual environments and tunnel operations. Further details are listed below. Firstly, an image luminance meter for tunnels that can implement the L20-method which is a tunnel luminance method that follows the international standards of CIE88, which was developed in order to improve and change the existing illumination-based tunnel lighting operation system to a luminance-based system. (The margin of error of below 5% according to the results of a test by an authorized agency and field test). Secondly, early illumination control is possible since the lighting control system that can be operated based on luminance enables interlocking control of the inside and outside of a tunnel using ethernet communication. Thirdly, guidelines for field application of the system are proposed. In addition, the luminance inducers of tunnels are found and the reflexibility of each facility that may reduce luminance of the boundaries is also proposed. Fourthly, as a result of a test bed, power consumption of luminance-based lighting operations decreased by 15.6% compared to illumination-based operations. Applying the feedback controls and maintenance factors of internal/external luminance meters, it reduced by 36.4%. Therefore, we became able to provide a luminance-based lighting operation system that complies with tunnel lighting design standards and provides a visual environment for drivers.

• Journal of the Korean Applied Science and Technology
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• v.26 no.1
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• pp.24-28
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• 2009

본 논문에서는 청색 인광 발광 물질인 bis(3,5-Difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium (III) (Flrpic)과 녹색 인광 발광 물질인 fac-tris(2-phenypyridine) irdium(III) ($Ir(ppy)_3$)와 적색 인광 발광 물질인 his(5-benzoyl-2-phenylpyridinato-C,N)iridium(III) (acetylacetonate) ($(Bzppy)_{2}Ir(acac)$)를 각각 적층하여 백색 유기 발광 다이오드를 제작하였고, 각각의 발광층 사이에 혼합된 스페이서인 4,4'-N,N'-dicarbazole-biphenyl (CBP):4,7-diphenyl-1,10-phenanthroline (BPhen)을 적층하여 그 때의 영향에 대하여 연구하였다. 최적화된 구조에서의 전력 효율은 $0.014\;mA/cm^2$에서의 19.7 lm/w를 나타내었으며, $0.127\;mA/cm^2$에서의 11.5%의 외부 양자 효율을 나타내었고, 8 V에서 Commission Internationale do I'Eclairage ($CIE_{x,y}$) coordinates (x=0.36, y=0.44)의 색좌표를 나타내었다.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.1
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• pp.9-15
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• 2002

In this thesis, blue emission organic light emitting devices were fabricated by using vacuum deposition method. Two types of device were employed to realize blue emission. Type I had an emitting layer containing TPB-doped $Alq_3$ and type II had an emitting layer containing DPA-doped $Alq_3$. The variable dopant concentration was 0.5 ~2 wt%. The electrical and optical characteristics of these devices have been investigated. The more dopant concentration increased, the nearer the blue coordinate. Type I than type II had a lower turn on voltage and driving voltage. The emission luminescence of type II was brighter than that of type I. When we applied 15V to type II with DPA(2wt%)-doped $Alq_3$, we have achived the emission luminescence of 1282cd/$m^2$, the emission wavelength of 476nm and the blue emission CIE coordination of (0.1273, 0.0672)