• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.179-184
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• 2012

A conventional wireless rf communication has relatively high ratio of power dissipation to transmit power for short-range links, susceptibility to interference, interception and jamming of electromagnetic wave. The study on alternative using ultraviolet signal to remedy the shortcomings of conventional rf communication has recently received attention. In this paper, the simulation results about the data rate performance of ultraviolet non-line-of-sight communication are provided. It is found that the direction of transmitting beam, receiving field of view width and the transmitting signal power have a seriously effect on the data rate of on-off-keying non-line-of-sight ultraviolet communication.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.733-738
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• 2020

In the recent years, the development of coastal zone has been advancing, and the chance of leisure activity has increased near the sea. However, the destruction of ozone layer has resulted in an increase in the amount of ultraviolet radiation reaching the earth surface. The human body is harmfully influenced as skin cancer and eye damage by ultraviolet radiation. Especially, the effect of ultraviolet radiation on beach is higher than that inland area due to the reflection from the sand. This study is expected to use basic data on the method of measuring ultraviolet reflections on east coast beaches using remote sensing.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1219-1226
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• 2017

In this paper, it is performed the optimal design of the UV LED bar which can be used variously. The UV LED Bar emits ultraviolet rays, so it is important to emit ultraviolet rays constantly for the purpose of use. In order to emit a certain amount of ultraviolet rays as ever, the ultraviolet ray emission should be driven by a constant current source within the operable input voltage range. And also the heat dissipation is particularly important because of the long ultraviolet emission retention time due to the UV utilization characteristics. In addition, since human body protection is essential, the algorithm is configured to operate according to human body detection using distance sensor and Bluetooth. Three 365nm UV LEDs were used in series to emit ultraviolet UVA, operating at the constant current of 500mA with an efficiency of 87.5% and a power consumption of 6.006W. The ultraviolet radiation dose was measured at $5.35mW/cm^2$ at the distance of 10 cm when measured by the Lutron ultraviolet measuring instruments.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.499-506
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• 2022

With the construction of the northern line of the East Sea in 2021, expectations for peaceful use of the Demilitarized Zone (DMZ) are rising. Accordingly, it is necessary to prepare for leisure tourism activities at nearby beaches using the Demilitarized Zone as a security ecological tourism. However, despite the increase in the amount of ultraviolet rays on the surface due to the destruction of the ozone layer, there are no guidelines for UV exposure. In this paper, the amount of ultraviolet reflection on the coast adjacent to the DMZ using remote exploration was measured and analyzed. It is hoped that the presented results will be used as basic data to prepare UV guidelines for leisure tourism activities in nearby areas.

• Biomolecules & Therapeutics
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• v.11 no.4
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• pp.224-231
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• 2003

The aim of this study was to investigate the effect of resveratrol on the oxidative stress-induced inhibition of gap junctional intercellular communication in HaCaT keratinocytes. Anti-oxidative activity of resveratrol was measured by $\alpha,\alpha$-diphenyl-$\beta$-picrylhydrazyl assay and dichlorodihydrofluorescein diacetate oxidation assay. Gap junctional intercellular communication in HaCaT keratinocytes was assessed using the scrape loading/dye transfer technique. Western blots and reverse transcription-polymerase chain reaction were also analyzed for connexin 43 protein and mRNA expression, respectively. Resveratrol scavenged directly the stable $\alpha,\alpha$-diphenyl-$\beta$-picrylhydrazyl radical over a concentration range of 4 mg/ml ($78.2{\pm}2.7$% of control) to 500 mg/ml ($29.9{\pm}4.2$% of control) and decreased the intracellular reactive oxygen species induced by ultraviolet A (UVA) irradiation ($89.3{\pm}1.1$% of UVA group), ultraviolet B (UVB) irradiation ($70.9{\pm}1.7$% of UVB group) and 12-0-tet-radecanoylphorbol-13-acetate (TPA, $48.3{\pm}1.1$% of TPA group), respectively. UVA irradiation and TPA markedly reduced gap junctional intercellular communication, which was restored by resveratrol. There were no significant differences in the level of connexin 43 protein and mRNA expression among any of the experimental groups. Our data suggests that resveratrol has the protective effect on the oxidative stress-induced inhibition of gap junctional intercellular communication in HaCaT keratinocytes, and this protection is likely due to the scavenging of reactive oxygen species.

• ETRI Journal
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• v.25 no.4
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• pp.253-257
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• 2003

This study investigated the photochromic properties and characterization of acetyl-substituted diarylethene (DAMBTF6)-doped fluoroacrylates media for holographic storage. For the rewritable holographic recording media, we prepared photochromic polymer films using an acrylate matrix by simple photocuring methods. Switching light sources from a visible (532 nm) to an ultraviolet (365 nm) produced transparent films that changed from pale yellow to red. Holographic recording was performed on the photochromic films by two interfering collimated plane wave beams. Excitation with a visible or ultraviolet light completely erased the records, and the film was rewritable either by 532 nm laser or by 325 nm laser within 2 seconds. Images were recorded onto a pixelated spatial light modulator with rectangular pixel apertures and reconstructed on the photochromic films to show recovery of the original images with high resolution.

• Journal of the Korean Graphic Arts Communication Society
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• v.15 no.2
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• pp.107-115
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• 1997

The ultraviolet(UV)-curable materials are widely used in inks and coatings. In this paper is designed to develop materials having flexibility and functionality with UV-curable acrylate monomer and alkyd resin. At first, phase diagram is prepared for miscibility of UV -curable acrylate monomer with alkyd resin. Also the gel fraction and dynamic viscosity are measured to curing speed of mixing system. In results, it has been demonstrated that miscibility and curing speed are greatly influenced by alkyd resin content.

• Journal of the Korean Graphic Arts Communication Society
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• v.10 no.1
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• pp.1-13
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• 1992

The recent results concerning the synthesis and application of spiroxazine dyes have been summerized., The absorption bands of usual spiroxazine dyes are changed from colorless to colored from by irradiation of ultraviolet ray. This mechanism is derived from the cleavage of oxazine ring. Such properties are dependent on its chemical structure and surrounded matrix of spiroxazine dyes. the chemical structure of this dye is similar to the well known spriopyran. But spiroxazine dyes have noticed recently, because of excellent high light-sensitivity and superior fatigue-resistant property. This dye are already applied as photochromic lens, cloths and UV light checker.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.3
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• pp.7-14
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• 2011

Many countries and researchers in the lighting field have focused on the LED light source as a solution to energy savings and environmental pollution. The LED light source consumes less power, has a long life and is highly economical. It is vibration and shock-resistant, and environment friendly as well. But LED lighting has some problems. In particular, the photobiological safety of LED light sources is emerging as an issue. Ultraviolet radiation from the LED light source emitted directly to the human body over a long period of time is harmful. In this paper, UV radiation from white LED was measured. Finally, the LED light source emits UV radiation, but it is relatively small when compared to others.

• International journal of advanced smart convergence
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• v.1 no.1
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• pp.61-64
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• 2012

The ultraviolet and visible light responsive properties of the amorphous indium gallium zinc oxide thin film transistor have been investigated. Amorphous indium gallium zinc oxide (a-IGZO) thin film transistor operate in the enhancement mode with saturation mobility of $6.99cm^2/Vs$, threshold voltage of 13.5 V, subthreshold slope of 1.58 V/dec and an on/off current ratio of $2.45{\times}10^8$. The transistor was subsequently characterized in respect of visible light and UV illuminations in order to investigate its potential for possible use as a detector. The performance of the transistor is indicates a high-photosensitivity in the off-state with a ratio of photocurrent to dark current of $5.74{\times}10^2$. The obtained results reveal that the amorphous indium gallium zinc oxide thin film transistor can be used to fabricate UV photodetector operating in the 366 nm.