• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.344-349
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• 2015

A new information society of late has arrived by the rapid development of various information & communications technologies. Accordingly, mobile devices which are light and thin, easy and convenient to carry on the market. Also, the requirements for the larger television sets such as fast response speed, low-cost electric power, wider visual angle display are sufficiently satisfied. The currently most widely studied display material, the Organic Light-emitting Diodes(OLEDs) overwhelms the Liquid Crystal Display(LCD), the main occupier of the market. This new material features a response speed of more than a thousand times faster, no need of backlight, a low driving voltage, and no limit of view angle. And the OLEDs has high luminance efficiency and excellent durability and environment resistance, quite different from the inorganic LED light source. The OLEDs with simple device structure and easy produce can be manufactured in various shapes such as a point light source, a linear light source, a surface light source. This will surely dominate the market for the next generation lighting and display device. The new display utilizes not the glass substrate but the plastic one, resulting in the thin and flexible substrate that can be curved and flattened out as needed. In this paper, OLEDs device was produced by changing thickness of Teflon-AF of hole injection material layer. And as for the electrical properties, the four layer device of ITO/TPD/$Alq_3$/BCP/LiF/Al and the five layer device of ITO/Teflon AF/TPD/$Alq_3$/BCP/Lif/Al were studied experimentally.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.270-275
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• 2012

This paper presents a portable and compact optical device which can conveniently be used to perform a functional analysis of human liver function. The proposed system employed red/green LEDs, as a light source, and CMOS image sensor, which is commonly used in cellular phones. With this system, several blood serum samples have been evaluated for liver functional analysis by measuring light absorption level through the blood serum samples depending on aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin concentration. The light absorption through the blood serum samples containing AST, ALT, or total bilirubin can provide their concentrations. The green light absorption is more sensitive to the concentration of AST or ALT, and the red light absorption is more sensitive to the total bilirubuin concentration. Additional calibration steps were performed by using a MATLAB program in order to eliminate the light scattering effects from the extraneous particles existing in each blood serum sample. From the blind test, three standard light intensity curves through each enzyme have been obtained and the enzyme concentration values have been compared to those obtained from a commercially available biochemistry analyzer (Toshiba 200 FR). The average percent difference in the obtained concentrations from two systems for AST, ALT, and total bilirubin concentration came out to be 7.79%, 7.98%. and 7.56%, respectively, with the adjusted coefficient of determination (R2) higher than 0.98. This system can possibly lead to a low-cost and simple system that can be used as a point-of-care (POC) system in a condition without advanced equipments.

• Journal of Nutrition and Health
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• v.39 no.6
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• pp.572-584
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• 2006

The purpose of this study was to compare the nutrient intake and diet quality of male college student according to smoking groups. Subjects were recruited and divided into three groups according to the smoking, which included non-smoker (n = 100), light-smoker (n = 78; packyear < 5), and heavy-smoker (n = 76; packyear ${\geq}$ 5). Subjects were interviewed using a general questionnaire, 24-hour recall method for dietary intake and diet quality. The average age of the subjects were 22.7 years for non-smoker, 23.5 years for light-smoker, and 23.4 years for heavy-smoker. Also the results showed that the heavy-smoker was significantly more often to drink coffee and alcohol compared with the other two groups (p<0.001, p<0.05). The mean daily energy intake was 2278.1 kcal in non-smoker, 2148.3 kcal in light-smoker, and 2144.4 kcal in heavy-smoker. The heavy-smoker consumed significantly lower intakes of vitamin C (p<0.001), calcium (p<0.01), animal calcium (p<0.01), and potassium (p<0.05) compared to the non-smoker and light-smoker. Also NAR (Nutrient Adequacy Ratio), ND (Nutrient Density), and INQ (Index of Nutritional Quality) of these nutrients in heavy-smoker were lower than the other two groups. Mean adequacy ratio (MAR) was 0.78 in non-smoker, 0.78 in light-smoker, and 0.74 in heavy smoker (p<0.05). The heavy-smoker consumed significantly lower intakes of fruits (p<0.001) compared to the non-smoker and light-smoker. The DVS (Dietary Variety Score) of heavy-smoker (26.8) was significantly lower than that 30.4 of non-smoker and 31.5 of light-smoker (p<0.01). In conclusion, heavy-smoker man have low intake status of vitamin C, calcium and potassium, and partly low diet quality. Therefore it was needed that well planed diet to replace the nutrients supplied from excluded food groups in heavy- smoker.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.548-561
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• 2020

Paecilomyces japonica is widely cultured to produce mycelium for medicinal and health food use. Illumination is an important factor in the growth and production of mycelium in submerged culture. The effects of different light-emitting diode (LED) combinations on the growth and cordycepin content as bioactive substances of mycelium were investigated. The results showed that the mycelium dry weights were lower under dark condition and red LED treatments. Dark condition, fluorescent light, and ultraviolet-A failed to increase the cordycepin content. Blue light was necessary to increase the cordycepin content, and a red-to-blue ratio of 3:7 induced the highest cordycepin content. The cordycepin contents of mycelium in submerged culture were significantly higher in a 12 h/day illumination time under red and blue (red-to-blue ratio of 3:7) LED treatments, showing an increase of up to 38% compared with those under the fluorescent-light control condition. The results demonstrated the roles of light with different wavelengths on the biosynthesis of cordycepin as bioactive substances. The low-heat release and replacement of traditional fluorescent lights with low-energy-consuming LEDs could increase the contents of bioactive substances. After optimization of the cordycepin production using response surface methodology (Box-Behnken design) to its canonical form, the optimum combination was found to be as follows: illumination time = 17.7 h/day, sugar content in the medium = 9.7 g/50 mL, and incubation time = 61.2 h. The model predicted a maximum response of 3779.2 ㎍/mL cordycepin yield.

• Journal of IKEEE
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• v.26 no.2
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• pp.205-210
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• 2022

We demonstrated roll-to-roll microcontact printed (mCP) microlens array (MLA) to enhance the light extraction of organic light emitting diodes (OLEDs). The commercially provided microlens array is used as a template for polydimethylsiloxane (PDMS) roll stamp. The fluorinated film is formed on the PDMS roll stamp from fluorinated ink with low boiling point and printed onto the bottom side of the organic light emitting diode without high pressure and high thermal treatment. With optimized concentration of ink, the pattern which is almost identical to that of the template MLA was successfully printed. Due to the structure and low optical absorbance of microcontact printed MLA, the external quantum efficiency of OLED was improved by about 18%.

• Journal of Auto-vehicle Safety Association
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• v.11 no.4
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• pp.16-21
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• 2019

In recent years, most automobile manufacturers have been using slim light source images to imprint their own brand image and identity. A light guide type lamp is widely used for making these kinds of a slim light source image. A light guide lamp means using a light emitting diode light source at one end of a long cylindrical pipe. The light from the light emitting diode source moves through the pipe by total reflection principle. Moving light is sent forward by various optic structures which is applied in the cylindrical pipe. However, the light guide lamp has a problem that the image of the light differs depending on the viewing direction, and in some cases there is dark section. It means light guide has low quality about lighting image. In this paper, trying to improve the fundamental problems of the light guide mentioned above by using various triz methods. Through functional modeling, estimating the factors affecting the light in the light guide lamp and make various ideas to improve the lighting image using the chain effect cause analysis, function oriented search scientific database techniques. Using these kinds of various TRIZ methods, finally find solutions that can improve the brightness and lighting uniformity of the light guide lamp. The ideas obtained in this paper were applied to actual vehicle development, and several patents achievements were obtained. In conclusion, it is proved that TRIZ method is useful for making ideas in actual automobile industrial field and is also a useful method for acquiring patent.

• Journal of Korean Society for Quality Management
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• v.46 no.1
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• pp.169-188
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• 2018

Purpose: The purpose of this study is to analyze low-temperature starting performance of the light attacker and to search and improve the aircraft system including battery and Battery Charge and Control Unit(BCCU). Methods: In order to improve the starting up performance of the light attacker at low-temp, various deficiency cause were derived and analyzed using Fault Tree Analysis method. As a result, it was confirmed there were drawbacks in the charging and discharging mechanism of the battery. The inactivation of the battery's electrolyte at low-temp and the premature termination of the battery charge were the main cause. After long error and trial, we improved these problems by improving performance of battery and optimizing the charging algorithm of BCCU. Results: It was confirmed that the problems of starting up failures were solved through the combined performance test of the battery and BCCU, the ground test using the aircraft system and the operation test conducted by Korea Airforce operating unit for 3 months in winter. Conclusion: This study showed that the improvement of quality reliability was achieved and thus the start-up performance issue of the light attacker has been resolved at low temperature. And it is expected that the design methodologies of temperature-affected electrical system of aircraft will contribute to the development of the aircraft industry in the future.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.227.2-227
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• 1997

No Abstract, See Full Text

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.390-400
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• 2011

Light rail are being constructed in cities have populations of mare than 700 thousand in the country as well as many cities in the world as an environmental and a low caron public transit. This paper reviews the capacity selections of electric power system about Light rail transit according to rail, vehicles, operation conditions.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.4
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• pp.30-40
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• 1999

The possibility of the characterization of sheet formation by image analysis with transmitted light was evaluated. Specific perimenter, average perimeter and variation could not be used to predict the sheet formation because there were no corrleation. Although image analysis method still have a lot of problems , it was found that the contrast intensity obtained by image analysis with transmitted light can be used to predict the sheet formation. In the case of highly filled sheet, the intensity of transmitted light was too low to characterize the sheet formation . However, it was possible to characterize the formation of unfilled heavy weight paper($\leq$200g/㎡).