• Korea-Australia Rheology Journal
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• v.15 no.3
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• pp.125-130
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• 2003

The emulsion stability of cosmetic creams based on the water-in-oil (W/O) high internal phase emulsions (HIPEs) containing water, squalane oil and cetyl dimethicone copolyol was investigated with various compositional changes, such as electrolyte concentration, oil polarity and water phase volume fraction. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The slope change of complex modulus versus water phase volume fraction monitored in the linear viscoelastic region could be explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsions: the greater the increase of complex modulus was, the more the coalescence occurred and the less consistent the emulsions were. Emulsion stability was dependent on the addition of electrolyte to the water phase. Increasing the electrolyte concentration increased the refractive index of the water phase, and thus decreased the refractive index difference between oil and water phases. This decreased the attractive force between water droplets, which resulted in reducing the coalescence of droplets and increasing the stability of emulsions. Increasing the oil polarity tended to increase emulsion consistency, but did not show clear difference in cream hardness among the emulsions.

• Transactions on Electrical and Electronic Materials
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• v.12 no.4
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• pp.156-159
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• 2011

SiNx:H films have been widely used for anti-reflection coatings and passivation for crystalline silicon solar cells. In this study, SiNx:H films were deposited using high frequency (13.56 MHz) direct plasma enhanced chemical vapor deposition, and the optical and passivation properties were investigated. The radio frequency power, the spacing between the showerhead and wafer, the $NH_3/SiH_4$ ratio, the total gas flow, and the $N_2$ gas flow were changed over certain ranges for the film deposition. The thickness uniformity, the refractive index, and the minority carrier lifetime were then measured in order to study the properties of the film. The optimal deposition conditions for application to crystalline Si solar cells are determined from the results of this study.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.7-11
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• 2012

SiNx films have been wildly used as anti-reflection coatings and passivation for crystalline silicon solar cells. In this study, the SiNx films were deposited by using high frequency (13.56MHz) PECVD and optical & passivation properties were investigated. The RF power was changed in a certain range for the film deposition. Then, the refractive index, etch rate, minority carrier lifetime and cell efficiency were measured to study the properties of the film respectively. The optimal deposition conditions for application to crystalline silicon solar cells were proposed as results of the study. Finally, the best cell efficiency of 16.98% was obtained from the solar cell with the SiNx films deposited by RF power of 550W.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.216-221
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• 2017

Reducing optical reflection in the visible light range, in order to increase the share of transmitted light and avoid the formation of ghost images in imaging, is important for polymer lens applications. In this study, polymer lenses with refractive indices of n=1.56, 1.60, and 1.67 were fabricated by the injection-molding method with a polymer lens monomer, dibutyltin dichloride as the catalyst and an alkyl phosphoric ester as the release agent. To investigate their anti-reflection (AR) effects, various AR coating structures, viz. a multi-layer AR coating structure, tri-layer AR coating structure with a discrete approximation Gaussian gradient-index profile, and tri-layer AR coating structure with a quarter-wavelength approximation, were designed and coated on the polymer lens by an E-beam evaporation system. The optical properties of the polymer lenses were characterized by UV-visible spectrometry. The material properties of the thin films, refractive index and surface roughness, were analyzed by ellipsometry and AFM, respectively. The most effective AR coating structure of the polymer lens with low refractive index, n=1.56, was the both side coating of multi-layer AR coating structure. However, both side coating of the tri-layered discrete approximation Gaussian gradient-index profile AR coating structure gave comparable results to the both side coating of the multi-layer AR coating structure for the polymer lens with a high refractive index of n=1.67.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.592-598
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• 2017

A method for estimating the optical characteristics of ceramic materials under high temperature conditions has been applied and evaluated. For that purpose, an interface system combined with a photo-spectrometer was made to keep the samples at the required high temperature. The transmittance of the samples was measured at various temperatures. The measured transmittance data was used to estimate the refractive index using an optical simulation model in conjunction with the Sellmeier equation. The Sellmeier equation parameters were selected by trial-and-error when the transmittance recalculated using the estimated refractive index was compared with the measured transmittance. Furthermore, the estimated refractive indices were checked by a comparison with the reference data at some typical wavelengths at room temperature.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.375-376
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• 2009

• Proceedings of the Materials Research Society of Korea Conference
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• 1995.11a
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• pp.15-15
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• 1995

• Journal of the Korean Chemical Society
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• v.54 no.4
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• pp.487-490
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• 2010

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.1-17
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• 2020

Three-dimensional microscopic approaches in histopathology display multiplex properties that present puzzling questions for specimens as related to their comprehensive volumetric information. This information includes spatial distribution of molecules, three-dimensional co-localization, structural formation and whole data set that cannot be determined by two-dimensional section slides due to the inevitable loss of spatial information. Advancement of optical instruments such as two-photon microscopy and high performance objectives with motorized correction collars have narrowed the gap between optical theories and the actual reality of deep tissue imaging. However, the benefits gained by a prolonged working distance, two-photon laser and optimized beam alignment are inevitably diminished because of the light scattering phenomenon that is deeply related to the refractive index mismatch between each cellular component and the surrounding medium. From the first approaches with simple crude refractive index matching techniques to the recent cutting-edge integrated tissue clearing methods, an achievement of transparency without morphological denaturation and eradication of natural and fixation-induced nonspecific autofluorescence out of real signal are key factors to determine the perfection of tissue clearing and the immunofluorescent staining for high contrast images. When performing integrated laboratory workflow of tissue for processing frozen and formalin-fixed tissues, clear lipid-exchanged acrylamide-hybridized rigid imaging/immunostaining/in situ hybridization-compatible tissue hydrogel (CLARITY), an equipment-based tissue clearing method, is compatible with routine procedures in a histopathology laboratory.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.125-129
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• 1997

The effects of the moisture and thermal annealing on CLBO crystal have been investigated. CLBO has hydrated at high humidity condition, resulting in 5B$_2$O$_3$$.$Cs$_2$O$.$8H$_2$O. The surface hydration seems to induce the cracking and the refractive index change in CLBO. The thermal annealing is effective to restore the changed index.