• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.309-310
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• 2017

SNS 사용량이 증가하고, 여러 촬영 기기들이 발달하면서 사진 촬영은 일상적인 일이 되었다. 많은 사람들은 스쳐 지나가는 순간들을 사진으로라도 간직하고자 수없이 셔터를 누르게 된다. 또한 마음에 드는 사진을 찍을 때 까지 끊임없이 촬영을 하게 된다. 이러한 현대인들의 문화에 발 빠르게 대응하지 못한 채, 기존 카메라 애플리케이션들은 다량의 필터 제공에만 초점을 맞추고 있다. 이에 대해 사진 촬영 시 좀 더 현실적인 도움을 줄 수 있는 사진 촬영 보조 기술을 개발하고자 한다.

• The Journal of Advanced Prosthodontics
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• v.6 no.6
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• pp.451-455
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• 2014

PURPOSE. The most common failure seen in restorations with a zirconia core is total or layered delamination of the ceramic veneer. In the present study, the shear bond strengths between veneering ceramics and colored zirconia oxide core materials were evaluated. MATERIALS AND METHODS. Zirconia discs ($15{\times}12{\times}1.6mm$) were divided into 11 groups of 12 discs each. Groups were colored according to the Vita Classic scale: A3, B1, C4, D2, and D4. Each group was treated with the recommended shading time for 3 s, or with prolonged shading for 60 s, except for the control group. Samples were veneered with 3 mm thick and 3.5 mm in diameter translucent ceramic and subjected to shear test in a universal testing machine with a crosshead speed of 1 mm/min. One-way analysis of variance (ANOVA) and Tukey's HSD tests were used for comparisons of the groups having the same shading times. A paired t-test was used for groups of the same color (3 s/60 s). RESULTS. Among the 11 groups investigated C4 (3 s) had the highest bond strength with a value of 36.40 MPa, while A3 (3 s) showed the lowest bond strength with a value of 29.47 MPa. CONCLUSION. Coloring procedures can affect zirconia/ceramic bond strength. However, the results also showed that bond strengths of all the investigated groups were clinically acceptable.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.8
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• pp.611-620
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• 2018

For the past decades, the analytic model for distributed surface roughness has been developed to improve the accuracy of the icing simulation code. However, it remains limitations to validate the developed model and determine the empirical parameters due to the absence of the quantitative experimental data which were focused on the surface state. To this end, the experimental study conducted to analyze the ice covered surface state from a micro-perspective. Above all, the tendency of the smooth zone width which occurs near the stagnation point has been quantitatively analyzed. It is observed that the smooth zone width is increased as growing the ambient temperature and freestream velocity. Next, the characteristics of the ice covered surface under rime and glaze ice have been analyzed. For rime ice conditions, ice elements are developed as the opaque circular corn in the opposite direction of freestream. The height and interval of each circular corn are increased as rising the ambient temperature. For glaze ice conditions, numerous lumps of translucent ice can be observed. This is because the beads formed by gravity concentrate and froze on the lower surface.

• Korean Journal of Materials Research
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• v.20 no.8
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• pp.444-449
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• 2010

Transparent ceramics are used in new technology because of their excellent mechanical properties over glasses. Transparent ceramics are nowadays widely used in armor, laser windows, and in high temperature applications. Silicon nitride ceramics have excellent mechanical properties and if transparent silicon nitride is fabricated, it can be widely used. h-BN has a lubricating property and is ductile. Therefore, adding h-BN to silicon nitride ceramics gives a lubricating property and is also machinable. Translucent silicon nitride was fabricated by hot-press sintering (HPS) and 57% transmittance was observed in the near infrared region. A higher wt. % of h-BN in silicon nitride ceramics does not favor transparency. The optical, mechanical, and tribological properties of BN dispersed polycrystalline $Si_3N_4$ ceramics were affected by the density, ${\alpha}:{\beta}$-phase ratio, and content of h-BN in sintered ceramics. The hot pressed samples were prepared from the mixture of $\alpha-Si_3N_4$, AlN, MgO, and h-BN at $1850^{\circ}C$. The composite contained from 0.25 to 2 wt. % BN powder with sintering aids (9% AlN + 3% MgO). A maximum transmittance of 57% was achieved for the 0.25 wt. % BN doped $Si_3N_4$ ceramics. Fracture toughness increased and wear volume and the friction coefficient decreased with an increase in BN content. The properties such as transmittance, density, hardness, and flexural strength decreased with an increase in content of h-BN in silicon nitride ceramics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.124-130
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• 2021

Dental prosthesis translucency importantly contributes to aesthetic outcomes. The purpose of this study was to investigate the effect of drying time and zirconia coloring agent type on translucency. For the experiment, 90 circular specimens were fabricated for each zirconia block. Then, zirconia specimens were treated with a coloring agent for 180 seconds and dried for 0 seconds (undried), 30 seconds (intermediate dry), or 30 minutes (complete dry). Then, a specimen was placed on a black standard tile or a white standard tile, and using a standard D65 light source reflected was measured using the light removal method. A total of three repeated measurements were obtained per specimen. One-way ANOVA was used to compare and analyze the relationship between zirconia translucency and drying time. Zirconia and coloring liquid types were significantly associated with translucency (P < 0.001). Although no significant difference was observed with respect to drying time (P > 0.922), zirconia in the completely dried (30 minutes) state was more translucent.

• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1533-1546
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• 2023

Nanoemulsion is an emulsion with a particle size of about 20 ~ 200 nm and has the advantage of having a transparent or translucent appearance and improving the skin permeability of an effective material with a small particle size, so it is applied in various fields. In this study, eight oils with different types of HLB and 16 oils with different types of required HLB were selected to investigate the effect of the required HLB and the type on the formation of nanoemulsion. The surfactants used at this time were Polysorbate 60 (HLB 14.9), Sorbitan state (HLB 4.7), PEG-60 hydrogenated castor oil (HLB 14.0), which were mixed with Polysorbate 60 and Sorbitan state, fixed with HLB 14.0, and Polysorbate 60 and PEG-60 hydrogenated castor oil, respectively. The formation of nanoemulsion was different depending on the type of oil, and oil with an ester structure showed a relatively excellent nanoemulsion formation ability. In particular, it was confirmed that a stable nanoemulsion was formed without a significant change after Cetyl ethylhexanoin was produced in a small size of 40 nm or less on average. In addition, it was found that using a mixture of Polysorbate 60 and Sorbitan stearate has a superior nanoemulsion formation ability than using PEG-60 hydrogenated castor oil or Polysorbate 60 alone.