• Journal of the Korean Society of Clothing and Textiles
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• v.7 no.1
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• pp.11-16
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• 1983

Variance of whiteness after graft copolymerization of acrylonitrile, methylmethacrylate and acrylamide onto bleached cellulose using Ce(IV) salt as initiators and the effect of homopolymer on the grafted fibers by photo-irradiation were studied. Also, the development of Yellowing were determined after carbon-arc radiation in a Fade-o-meter. The results were as follows: (1) Variation of whiteness of grafted cellulose fibers were influenced by graft-ratio, Inorganic-Organic Balance (IOB) of functional group in used monomers and adhering homopolymers on the grafed fibers. (2) Yellowing was not affected by the concentration of Ceric Ammonium Nitrate directly during reaction (eg. 0.008>0.006>0.014 M).

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.26-26
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• 2012

The hydrophobic nature of the wool surface give rise to difficult penetration of dye molecules. Among all the methods of modification, graft polymerization is an attractive method to impart a variety of functional groups to a polymer. Grafting has been made by irradiating the light on the polymer in the presence of a solvent containing monomer. The energy source commonly used are high-energy electrons, X-rays, UV and visible light. UV irradiation is a relatively low-energy radiation in comparison with others since it has the least possibility to change bulk properties. In the present paper, a photo-reactive dye was synthesized from quinizarin by the reaction with methacryloyl chloride. The synthesized dye was continuously grafted onto wool fabric at room temperature by UV irradiation. Several key parameters including UV energy, dye concentration and pH have been examined to understand their influence on the photoreactive coloration.

• Journal of Pharmaceutical Investigation
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• v.26 no.2
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• pp.83-89
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• 1996

A reverse-phase HPLC method to determine DL-Carnitine Hydrochloride in pharmaceutical preparation is described. UV absorption derivatives of DL-Carnitine Hydrochloride were formed with p-Bromophenacyl Bromide in an essentially quantitative manner using crown ether as catalyst. The DL-Carnitine-bromophenacyl ester absorbed UV radiation strongly at 254nm, allowing the detection of as small a quantity as 12.5ng of DL-Carnitine Hydrochloride. A linear defection range was $5\;{\times}\;10-8 \;{\sim}\;5\;{\times}\;10-7M$ of DL-Carnitine Hydrochloride. And the linear regression at various drug concentration was =0.999 (n=10). The DL-Carnitine Hydrochloride in pharmaceutical preparation was successfully derivatized and separated from other constituents by reverse phase HPLC with detection at 254 nm.

• Journal of the Korean Society of Combustion
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• v.4 no.2
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• pp.75-83
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• 1999

The effect of temperature distributions on soot volume fraction in double-concentric diffusion flames have been investigated experimentally. Using fine thermocouple wires and a rapid insertion mechanism, we have measured temperature without the effect of soot particles attached to the thermocouple junction, which can lower the temperature signal about 100 K by increasing the heat loss from the junction by radiation. The temperature at the flame axis is higher in the double-concentric diffusion flames than in normal co-flow diffusion flames because of the inverse diffusion flame. However, it is almost the same as that at the periphery of normal flames, on which the inverse flame does not have an effect. Thus, the lower soot concentration found in the double-concentric diffusion flame can be explained by the effect of nitrogen diffusion from the central air jet.

• Journal of the Korean Solar Energy Society
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• v.21 no.2
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• pp.9-17
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• 2001

In this paper the attempts made by the authors to explore the feasibility of utilising concentrated solar beam radiation for joining engineering thermoplastics such as Acrylonitrilc/Butadiene/Styrene (ABS), Polycarbonate(PC) and Polymethylmethacrylate(PMMA) are presented. In addition, to study the joining of the materials, necessary experimentation with applying primer was performed. Tensile tests were conducted to determine the bond strength achieved at the specimen joint interface. Microscopic examinations of the fractured joints were performed in order to analyse the overall bond quality. Finally, the results in terms of bond strength achieved at the joint interface and energy consumed in the process were compared with those obtained with similar thermoplastic joining technique utilising microwave energy. In conclusion some advantages and limitations were outlined and necessary improvements of the jointing technique were recommended.

• Journal of Hydrogen and New Energy
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• v.29 no.2
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• pp.226-234
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• 2018

Even though the nuclear power plants has many advantages, safety issues of nuclear power plants are crucial factors of reliable operation. A tritium detector is a useful sensor to analyze amount of exposed radiation from the nuclear power plants. Currently, concentration of underwater tritium is measured precisely but it takes very long time. Since electrolysis is extracted hydrogen from the coolant of nuclear power plant, it can motivate to develop new type of real-time sensor. In this study, Proton Exchange Membrane (PEM) electrolyzer is studied for candidate as preprocessor of real-time tritium detector. Characteristics of the unit PEM electrolyzer were experimentally investigated. A simulation model is developed to understand physical behavior of unit PEM electrolyzer under dynamic operation.

• Journal of IKEEE
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• v.22 no.2
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• pp.484-487
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• 2018

5 MeV proton-irradiation with total dose of $10^{15}/cm^2$ was performed on AlGaN/GaN-on-Si high electron mobility transistors (HEMTs) with various gate metals including Ni, TaN, W, and TiN to investigate the degradation characteristics. The positive shift of pinch-off voltage and the reduction of on-current were observed from irradiated HEMTs regardless of a type of gate materials. Hall and transmission line measurements revealed the reduction of carrier mobility and sheet charge concentration due to displacement damage by proton irradiation. The shift of pinch-off voltage was dependent on Schottky barrier heights of gate metals. Gate leakage and capacitance-voltage characteristics did not show any significant degradation demonstrating the superior radiation hardness of Schottky gate contacts on GaN.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.9
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• pp.3007-3014
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• 1996

The instantaneous flame temperature and soot formation and oxidation in a D.I. diesel engine are measured using a two-color method. The proposed method based on the continuous spectral radiation from the soot particles in the flame is applicable to industrial diesel engines without major modifications of their main characteristics. Measurements are performed at one location inside the combustion chamber of a D.I. diesel engine. Effects of different engine speeds and loads on flame temperature and KL factor which is an index of soot concentration were examined. Little temperature change were observed with increasing rpm, while increased with loads. The higher the flame temperature is, the lower the KL factor is.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.441-446
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• 1998

As for safety assessment of a radioactive waste disposal facility, radiation dose to inadvertent intruders is evaluated according to scenarios related to intruder's postulated activities at the disposal site after the end of Institutional Control Period(ICP). Simple trench and Below Ground Vault(BGV) are considered for this study as alternative disposal systems, and different scenarios are applied to each disposal type. The results show that 300 years of ICP is needed for simple trench and 100 years for BGV. Even for BGV, concentration of long-lived radioactive nuclides should be limited considering degradation of BGV after 300 years.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.373-380
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• 2020

This study was carried out to convert the hydrophobic characteristics of PVDF to hydrophilic. Poly(-vinylidene fluorine) (PVDF) was grafted by electron beam irradiation and sulfonated. The grafting degree of modified PVDF increased with the monomer concentration, but not the conversion degree. From the results of FTIR and XPS, it was shown that the amount of converted sulfur increased with the grafting degree. The radiation-induced graft polymerization led to decrease fluorine from 35.7% to 21.3%. Meanwhile, the oxygen and sulfur content increased up to 8.1% and 3.2%. The pore size of modified membranes was shrunken and the roughness sharply decreased after irradiation. The ion exchange capacity and contact angle were investigated to show the characteristics of PVDF. The enhanced ion exchange capacity and lower contact angle of modified PVDF showed that the hydrophilicity played a role in determining membrane fouling. Electron beam irradiation successfully modified the hydrophobic characteristics of PVDF to hydrophilic.