• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.433-438
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• 2004

Clusters of galaxies generally form by the gravitational merger of smaller clusters and groups. Major cluster mergers are the most energetic events in the Universe since the Big Bang. The basic properties of cluster mergers and their effects are discussed. Mergers drive shocks into the intracluster gas, and these shocks heat the intracluster gas. As a result of the impulsive heating and compression associated with mergers, there is a large transient increase in the X-ray luminosities and temperatures of merging clusters. These merger boost can affect X-ray surveys of clusters and their cosmological interpretation. Similar boosts occur in the strong lensing cross-sections and Sunyaev-Zeldovich effect in merging clusters. Merger shock and turbulence associated with mergers should also (re)accelerate nonthermal relativistic particles. As a result of particle acceleration in shocks and turbulent acceleration following mergers, clusters of galaxies should contain very large populations of relativistic electrons and ions. Observations and models for the radio, extreme ultraviolet, hard X-ray, and gamma-ray emission from nonthermal particles accelerated in these shocks will also be described. Gamma-ray observations with GLAST seem particularly promising.

• Journal of the Korean Applied Science and Technology
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• v.34 no.1
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• pp.41-49
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• 2017

In this study, to evaluate antioxidant activity and safety on skin of Arctium lappa L. root extract, antioxidant activity was understood through total content of polyphenol, total content of flavonoid and DPPH radical scavenging activity, and cytotoxicity for B16F10 melanoma and skin cell protection effect for ultraviolet rays A were confirmed. To verify the application as cosmetic material, the first skin patch test was performed. The result of this experiment showed that as the content of Arctium lappa L. root extract increased, the content of polyphenol and flavonoid increased, and DPPH radical scavenging activity was confirmed. The result of checking cytotoxicity for B16F10 melanoma cells showed that it had low toxicity, and over 80% cell protection effect for ultraviolet rays A was confirmed. In addition, through the first skin patch test, Arctium lappa L. root extract was confirmed to have almost no skin irritation. Through this result, Arctium lappa L. root extract is excellent in skin protection from ultraviolet rays, has low toxicity for skin cells and is safe on skin, so its possibility of being a cosmetic ingredient was verified.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1202-1205
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• 2000

Germicidal lamps efficiently emit a large amount of ultraviolet rays 253.7nm which have excellent germicidal effect. The lamps are primarily useful for sterilization of air, the surface of various materials and water or liquid. In this paper, analysis of the charge pump power factor correction inverter for driving a 65W UV lamp and electrical characteristics of the lamp are discussed. The operation of the inverter circuit. in which the lamp is included as a load, is analyzed. Experimental results of the inverter circuit are also presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.395-398
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• 2000

In this study mechanical and environment ability of FRP pole for a distribution line about high strength and good insulation properties. The basic filament winding process creates a helical winding pattern. In mechanical analysis of splice with mechanical fastened joint it is important to evaluate a critical load of faster having maximum stress. It is also present a result of several examples to compare this with analytical one. On repair design this finite element method will be used as basis. The influence of environmental factors, such as elevated temperatures, high humidity, and corrosive fluids, and ultraviolet(UV) rays, upon the performance of polymeric matrix composite is of concern in many applications.

• Korean Journal of Microbiology
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• v.10 no.2
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• pp.73-78
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• 1972

As the first step in the production of nucleic acid derivatives by microorganisms, adenineless mutants were derived from Brevibacterium ammoniagenes ATCC6872. A culture of Br. ammoniagenes was exposed to ultraviolet rays for 120 second and treated with diethylsulfate in phosphate buffer for 2 hours to reach the designed death rate. The yield of mutants induced was 0.28% by the ultraviolet irradiation and 0.66% by the diethylsulfate treatment. By the diethylsulfate treatment. By the treatment of penicillin G in a hypertonic minimal medium, the yield of mutants was increased from 0.28% to 0.54% and from 0.66% to 1.5%, respectively. Thus, in was demonstrated that diethylsulfate treatment was much more efficient than UV irradiation to induce adenineless mutants of the bacteria, and total strains of 120 adenineless mutants were obtained.

• Journal of the Korean Medical Association
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• v.61 no.11
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• pp.644-648
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• 2018

The incidence of skin cancer has continuously increased in Korea, probably due to sun exposure and increases in the aging population. Ultraviolet light, a well-known risk factor for skin cancer, can cause DNA damage, mutation, and immune suppression, followed by abnormal proliferation. To prevent photocarcinogenesis, the appropriate use of sunscreen should be emphasized. Using broad-spectrum sunscreens with sun protection factor values of 15 or higher and frequent reapplication are recommended. Controversy exists about whether vitamin D synthesis is inhibited by the use of sunscreen. However, considering that skin cancer most commonly develops on the head and neck area, applying it to the face and neck is reasonable in terms of balancing the risk-benefit ratio.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.55.4-55
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• 2002

In the semiconductor fabrication, particle contamination is wide-spread and one of major causes to yield loss. Extensive testing has revealed that even careful handling of wafers during processing may cause photo-resist materials to flake off wafer edges. So, to remove the photo-resist at the outer 5mm of wafers, UV(Ultraviolet) rays are exposed. WEE (Wafer Edge Exposure) process station is the system that exposes the wafer edge as prespecified by controlling the positioning mechanism and maintaining the light intensity level In this work, WEE process station has been designed so as to significantly lower the amount of particle contamination which occurs even during the most r...

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1995.10a
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• pp.13-18
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• 1995

To evaluate the color change of the dyed materials by ultraviolet and visible rays in the museum, a system that accelerates dye fading was developed. Radiation energy from a Xenon lamp is irradiated on the samples through the filters of defferent cut-on wavelengths. As a result, the color change as a function of the wavelength and irradiation is calculated.

• Proceedings of the KIEE Conference
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• 2005.10a
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• pp.169-172
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• 2005

The simulation of Hydraulic pressure distribution of discharge tube with globular beads and the removal characteristic of Escherichia coli by the discharge tube with globular beads were estimated. The removal characteristic of Escherichia coli was related to the input voltage because the electric field is increased according to input voltage. As the passing amount of test water in discharge tube is increased, the removal ratio of Escherichia coli was increased because passing numbers of electric field section is increased.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.251-257
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• 2021

ln this study, natural extracts extracted from cypress sapiens, a natural material, were investigated as materials that could protect skin aging caused by ultraviolet rays, and experiments were conducted on the synthesis of filaggrins that make up the natural moisturizing factor of the skin, the synthesis of pro-colagen, a fibrous protein, which plays an important role in moisturizing the dermis, and elastin, which is an enzyme that decomposes collagen. As a result, cypress ethanol extract (COE) was a dependent inhibitor to collagenase and elastase, inhibiting the synthesis of filaggrin and the expression of MMP-1 for exfoliated cells damaged by ultraviolet rays. Therefore, it is estimated that ethanol extract will have the effect of delaying wrinkles and as a functional cosmetic material that inhibits skin aging convergence. Based on this study, we would like to further study the mechanism of the synthesis of filaggrin on the suppression of expression of MMP, which is the anti-wrinkle effect.