• Proceedings of the KACD Conference
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• 2001.11a
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• pp.579-579
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• 2001

One of the most important factors for the clinical success of adhesive posterior restorations is marginal adaptation. This property is very closely related to mechanical properties and to the shrinkage behavior of composite materials. Most of modem composite materials are light-cured. This is why the first part of this lecture will be confined to our recent research on light curing, such as plasma polymerization, LED polymerization and the power of modem halogen lamps. In the second part of the lecture the shrinkage properties such as dimensional shrinkage and shrinkage forces of different light curing materials and during different curing procedures will be discussed. Finally, in the third part of the lecture, marginal adaptation before and after loading in different cavity classes and by using different restorative techniques and curing procedures will be presented. Data will also be given on wear resistance, abrasiveness against opposing cusps and postcuring of composite materials.(omitted)

• Journal of the Korean Chemical Society
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• v.6 no.1
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• pp.64-68
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• 1962

The graft polymerization of styrene to polyvinyl alcohol using a photosensitizer(benzophenone) and ultraviolet light was studied. Styrene was grafted onto polyvinyl alcohol up to when polyvinyl alcohol was pre-immersed in water and irradiated by ultraviolet light for 24 hours styrene solution of benzophenone(0.01 molarity). The highest percentage of graft obtained in the grafting which was proceeded in the presence of water added immediately before irradiation was 29%. The grafting was proportional to irradiation time within a certain limit of time, i.e., 24 hours, and presumably was initiated at the surface. After a certain degree of grafting a definite maximum was reached. Graft polymer prepared in this experiment showed high resistance to various solvents.

• Transactions on Electrical and Electronic Materials
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• v.3 no.1
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• pp.38-41
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• 2002

We have investigated current-voltage-luminance characteristics of organic light-emitting diodes based on TPD/Alq$_3$organics depending on the application of forward-backward bias voltage. Luminance-voltage characteristics and luminous efficiency were measured at the same time when the current-voltage characteristics were measured. We have observed that the current-voltage characteristics shows a reversible current maxima at low voltage, which is possibly not related to the emission from Alq$_3$. Current-voltage-luminance characteristics imply that the conduction luminance mechanism at low voltage is different from that of high voltage one.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1764-1768
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• 2009

As the demand of electric power is increasing rapidly, the need of the compact and light electric power device is also increased. Copper clad aluminum (CCA) is newly proposed electrical conductor, because of its light-weight and low-cost characteristics, to replace the existing conductor made of copper. This paper presents the salt-proof characteristics of the copper clad aluminum (CCA) to certificate long time safe operation of the newly proposed electrical conductor. The two types of the CCA conductor were tested in the neutral salt spray tester. The experimental results of two types of the CCA with salt spray were presented in this paper. The results comprise resistance measured data, micro picture of the selected surface, and component measured data according to the elapsed time. The period of the experiment was 1,000 hours. There was no evidence to show the corrosion of CCA during the whole period of the experiments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.188-191
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• 2004

We have investigated equivalent-circuit analysis of organic light-emitting diodes in $ITO/TPD/Alq_3/Al$. Complex impedance Z of the device was measured in the frequency range of $40Hz{\sim}1MHz$. We are able to interpret the frequency-dependent response in terms of equivalent-circuit model of contact resistance $R_s$ in series with two parallel combination of $R_{TPD},\;C_{TPD}\;and\;R_{Alq3},\;C_{Alq3}$.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.530-536
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• 1998

In the design of the light rail transit which is more reliable and economical, it is essential to develope a efficient third rail system. Especially, the analysis for the conductivity of conduct rail and the wear of collecting shoe is the first step of its development. In this paper, experiments for conductivity in conductor rail, wear in collecting shoe were performed respectively as different materials of conductor rail and current collector. Noise level and interruption, wear and contact resistance of collecting shoe were proposed as design parameters for the development of this system. Experimental equipment and methods of design parameter stated above were proposed, which is expected that analyzed results will be used as a basic data for the development of the system.

• 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.

• Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.28.1-28.7
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• 2016

Background: Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm) on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results: We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and $68.4J\;cm^{-2}$, respectively, produced one log reduction in the bacterial populations), whereas Streptococcus parauberis was the least susceptible ($153.8J\;cm^{-2}$ per one log reduction). In general, optical density (OD) values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions: This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1759-1761
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• 2004

In this paper, we studied on life-decision of underground cable of live-line state. Data of CV 6.6kV and 22kV cable's life is got data measured insulation resistance by D.C. overlapped current. We confirmed that D.C resistance reduced by time. Aging of cable could be occurred by electrical, thermal, mechanical stress and complex aging confirmed that proceeded by Weibull plot. In the result, life of 6.6kV cable remained 21 years till light caution and 35 years till heavy caution, so aging of 6.6kV XLPE cable was not occurred. Life of 22kV cable remained 10 years till light caution and 22 years till heavy caution. We confirmed that the designed life of 22kV cable is similar to the measured life.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.6
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• pp.955-967
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• 1995

This study was performed to investigate the physical and chemical properties of the 5 kinds of fabrics dyed with persimmon juice and undyed fabrics. The difference between dyed and undyed fabrics was checked experimentally. Obtained results are as follows. 1. Bending length and flex stiffness were increased after dyeing, and tensile strength of waif i3l fabrics except Ramie was also increased. 2. Abrasion resistance was improved in Ramie and Hemp after dyeing but the rest of fabrics were decreased. 3. Crease resistance of dyed fabrics was roughly worse than that of undyed fabrics. 4. Air permeability remarkably increased after dyeing and this fact estabilished that the traditional Gal-01 was cool clothing. 5. Water repellency in Cotton 1 and Polyester rises but the rest of fabrics were not changed. Therefore it is found that this repellency related to the their fabric counts. 6. Blocking effect of UV light and visible ray was increased in all dyed fabrics. Especially dyed Cotton 1 and Polyester blocked UV light almost perfectly. 7. The colorfastness to soaping and sunlight was proved to less than 3 grade in all fabrics after dyeing. It indicates that this colorfastness became worse owing to dyeing. 8. The colorfastness to dry cleaning and water was decided to more than 3 grade in all fabrics. 9. The colorfastness of the dyed fabrics to sweat after exposing to man-made acid sweat solution was good so that was decided above 3 grade. However after exposing to man-made alkalic sweat solution it became worse owing to dyeing.