• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.3
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• pp.108-112
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• 2007

Cubic Zirconia single crystals having changeable color with light source were grown by skull melting method. Strong absorption of yellow color region light by Co and Nd and the absorption in violet color region by Fe led the color change from blue-green to red-purple with the light source from fluorescent to incandescent lamp. Color of crystals varied not only by the dopants but yttria contents and the conditions far heat treatment.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.382-386
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• 2005

In this paper we introduce a fire-detection system which is robust to light sources and environment changing. We can decide the threshold values that classify the regions between a fire flame and light sources by analyzing them in RGB color space. The mean histogram difference technique make it possible to extract flame region more efficient because fire flame is continuously changing after it occurs. In order to detect flame region, this paper proposes to count fire pixels.

• Journal of the Semiconductor & Display Technology
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• v.6 no.3
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• pp.47-53
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• 2007

Ultra thin Si p-n junctions shallower than $300{\AA}$ were fabricated and biased to the avalanche regime. The ultra thin junctions were fabricated to be parallel to the surface and exposed to the surface without $SiO_2$ layer. Those junctions emitted white light and electrons when junctions were biased in the avalanche breakdown regime. Therefore, we could observe the avalanche breakdown region visually. We could also observe the influence of electric field to the current flow visually by observing the white light which correspond to the avalanche breakdown region. Arrayed diodes emit light and electrons uniformly at the diode area. But, the reverse leakage current were larger than those of ordinary diodes, and the breakdown voltage were less than 10V.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.2
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• pp.55-60
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• 2006

In order to suppress lasing oscillation and obtain high light power, We have proposed a novel SLD which is formed with a straight and tilted waveguide. The window region is used to suppress lasing oscillation and reduce the facet reflectivity. High power and low reflectivity is obtained by the straight and tilted waveguide. Based on the theoretical analysis, we have fabricated the SLD with the waveguide of 500 $\mu$m length and window region of 50 $\mu$m by LPE equipment. Through the measurements of optical characteristics, the output light power of 3 mW was obtained at the 150 mA CW injection current and 25$^{circ}C$. We have confirmed that the proposed SLD has a 0.8 dB spectrum ripple lower than 1 dB which is sufficiently low reflectivity for preventing lasing.

• Biomedical Science Letters
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• v.25 no.4
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• pp.372-380
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• 2019

Mice with specific modified genes are useful means of studying development and disease. The CRISPR/Cas9 system is a very powerful and effective tool for generating genetically modified mice in a simple and fast manner. To generate human IgG light kappa constant knock-in mice, we tested by microinjection of a mixture of Cas9 protein, single-guide RNA and target homologous recombinant donor DNA into zygotes. We found that the injection of 10 ng/μL of Cas9 protein and crRNA/tracrRNA, rather than single guide RNA, induced the production of knock-in mice more effectively. Thus, our study provides valuable information that will help to improve the production of knock-in mice and contribute the successful generation of humanized Ab-producing mice in Korea.

• Korean Journal of Materials Research
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• v.27 no.6
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• pp.312-317
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• 2017

In the construction of a white LED, the region of the red emission is a very important factor. Red light emitting materials play an important role in improving the color rendering index of commercial lighting. These materials also increase the color gamut of display products. Therefore, the development of novel phosphors with red emission and the study of color tuning are actively underway to improve product quality. In the present study, heuristic algorithms were used to search for phosphors capable of increasing the color rendering index and color gamut. Using a heuristic algorithm, the phosphors that were identified were $SrGe_4O_9:Mn^{4+}$ and $BaGe_4O_9:Mn^{4+}$. Emission spectra study confirmed that these phosphors emit light in the deep red wavelength region, which can fulfill the requirement for the improvement in color rendering index and color gamut for a white LED.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.163-165
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• 2012

Impedance spectroscopy informs electrical properties of materials as accumulated charges, contact status between electrode and organic materials. We carried out impedance spectroscopy of organic light-emitting diodes as ITO/Alq3(60 nm)/Al on temperatures from 10 K to 300 K. The result described Z'-Z" plot, cole-cole plot and dielectric relaxation time τ. Z'-Z" plot means that real and imaginary part of materials in organic and electrode by frequencies and temperature. Z' as real part of impedance by applied frequency depending on temperature shows the plateau in low frequency region as Rs+ Rp and over 100 kHz in high frequency region as Rs. Cole-cole plot shows resistance of materials in equivalent circuit of the device by temperatures. And equivalent circuit and dielectric relaxation could be accomplished by using the complex impedance analysis.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.530-540
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• 2008

The temporal and spatial variations of size-structured phytoplankton dynamics in Youngsan Lake were investigated to explore potential mechanims controlling the dynamics in the Youngsan Lake. Field data were collected monthly from February to October, 2003 at 6 stations along the axis of Youngsan Lake. In this study, phytoplankton (chlorophyll $\alpha$) were categorized into three size classes: micro-size ($>20{\mu}m$), nano-size ($2{\sim}20{\mu}m$) and pico-size ($<20{\mu}m$). Water temperature, light attenuation coefficients, PAR (photosynthetically active radiation) and suspended solids were measured to analyze relationship between physical-chemical properties and size structure of phytoplankton. Phytoplankton blooms developed during March, July and October in the upper region of the main stem whereas small-scaled spring bloom was observed in the lower region. The scales of phytoplankton blooms were higher in the upper regions than the lower region and blooms were predominated by micro-size class in upper region but predominated by nano-size class in lower region. Growth of size-structured phytoplankton appeared to be controlled by rather light availability than temperature-dependant metabolisms in the system. Phytoplankton growth may be also supported by ambient nutrients available in the water column from analyses of chlorophyll $\alpha$ vs. nutrient concentrations including nitrite+nitrate and orthophosphate. Growth of nano-sized phytoplankton alone appeared to be supported by orthophosphate as well as nitrite+nitrate indicating that response of phytoplankton to nutrient inputs may be size-dependent.

• Journal of the Korean institute of surface engineering
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• v.56 no.4
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• pp.233-242
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• 2023

In recent years, energy-management studies in buildings have proven useful for energy savings. Typically, during heating and cooling, the energy from a given building is lost through its windows. Generally, to block the entry of ultraviolet (UV) and infrared (IR) rays, thin films of deposited metals or metal oxides are used, and the blocking of UV and IR rays by these thin films depends on the materials deposited on them. Therefore, by controlling the thicknesses and densities of the thin films, improving the transmittance of visible light and the blocking of heat rays such as UV and IR may be possible. Such improvements can be realized not only by changing the two-dimensional thin films but also by altering the zero-dimensional (0-D) nanostructures deposited on the films. In this study, 0-D nanoparticles were synthesized using a sol -gel procedure. The synthesized nanoparticles were deposited as deep coatings on polymer and glass substrates. Through spectral analysis in the UV-visible (vis) region, thin-film layers of deposited zinc oxide nanoparticles blocked >95 % of UV rays. For high transmittance in the visible-light region and low transmittance in the IR and UV regions, hybrid multiple layers of silica nanoparticles, zinc oxide particles, and fluorine-doped tin oxide nanoparticles were formed on glass and polymer substrates. Spectrophotometry in the UV-vis-near-IR regions revealed that the substrates prevented heat loss well. The glass and polymer substrates achieved transmittance values of 80 % in the visible-light region, 50 % to 60 % in the IR region, and 90 % in the UV region.

• Journal of Photoscience
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• v.5 no.4
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• pp.149-152
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• 1998

Expression of light-harvesting chlorophyll a/b-binding protein gene(cab) is repressed in the dark and activited by light. However, the detail of its regulatory mechanism is not characterized so far. To identify the interactions of cis-acting elements and trans-acting factors involvedin this regulation, nuclear extracts from the light-grown and dark-adapted Arabidopsis thaliana leaves were anlayzed for mobility shift assay against 134bp fragments had two retarded bands and one retardation band, respectively, both in light-grown and dark-adapted bands in the dark-adapted tissues. A new retardation the cab 3 expression in the dark. Several light regulatory motifs are scattered in the 146 bp region of cab 3 promoter. One of the light-regulatory motifs could be the binding site for the negative regulatory factor.