• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.142-143
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• 2008

In the present work, high-speed video images of the ground take-off flight of a live butterfly were captured and their dynamic motions during the first full-stroke were analyzed. To capture the dynamic images of the take-off motion, the experimental setup consisted of a high-speed camera, a Xenon lamp as a light source and a transparent chamber of $15^W{\times}15^L{\times}17^H$ $cm^3$ in physical size. The ambient temperature and supplementary lighting devices were precisely controlled. The weight and wing span of the butterfly tested in this study was 104 mg and 63.14 mm, respectively. The ground take-off images were captured with 4000 fps with a spatial resolution of (1024${\times}$512) pixels. The period of the first full-stroke was 80.5ms and the flapping speed of downstroke was 2 times faster than that of upstroke. As a result, butterflies used the fling and near-clap motion to generate lifting force and an interesting take-off behavior of early pronation and downstroke was observed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1416-1425
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• 2002

In this study, the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated by the use of an accelerated aging test. Environmental factors such as temperature, moisture. and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile. bending, and shear specimens those are transverse to the fiber direction, and bending specimens those are parallel to the tiber direction - were used to investigate the effects of environmental factors on mechanical properties of the composites. Also, glass transition temperature, storage shear modulus, loss shear modulus, and tan ${\delta}$ were measured as a function of exposure times through a dynamic mechanical analyzer. In addition. a suitable testing method for determining the effect of environmental factors on mechanical properties is suggested by comparing the results from using two different types of strain measuring sensors. Finally, composite surfaces exposed to environmental factors were examined using a scanning electron microscope.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.123-126
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• 2003

Recently, there is a growing concern on the photovoltaic effects using organic materials. This is a phenomena which converts the solar energy into the electrical one. We have fabricated a device structure of $ITO/PEDOT:PSS/CuPc/C_{60}/BCP/AI$. The PEDOT:PSS layer is made by spin coating, and the other organic layers are made by thermal vapor deposition. By measuring the current-voltage characteristics with an illumination of light, we have obtained value of Voc=0.38V, Jsc=$0.5mA/cm^{2}$. And a fill factor and efficiency are about 0.314 and 0.083%, respectively. A 500W xenon lamp(ORIEL) is used for a light source, and the light intensity illuminated into the device was about 10mW.

• International Journal of Railway
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• v.1 no.3
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• pp.113-116
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• 2008

The long-tenn exposure of polymeric composite materials to extreme-use environments, such as pressure, temperature, moisture, and load cycles, results in changes in the original properties of the material. In this study, the effect of combined environmental factors such as ultraviolet ray, high temperature and high moisture on mechanical and thermal analysis properties of glass fabric and phenolic composites are evaluated through a 2.5 KW accelerated environmental aging tester. The environmental factors such as temperature, moisture and ultraviolet ray applied of specimens. A xenon-arc lamp is utilized for ultraviolet light and exposure time of up to 3000 hours are applied. Several types of specimens - tensile, bending, and shear specimens that are warp direction and fill direction are used to investigate the effects of environmental factors on mechanical properties of the composites. Mechanical degradations for tensile, bending and shear properties are evaluated through a Universal Testing Machine (UTM). Also, storage shear modulus, loss shear modulus and tan a are measured as a function of exposure time through a Dynamic Mechanical Analyzer (DMA). From the experimental results, changes in material properties of glass fabric and phenolic composites are shown to be slightly degraded due to combined environmental effects.

• Korean Journal of Materials Research
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• v.25 no.3
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• pp.144-148
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• 2015

Cubic mesocrystal $CeO_2$ was synthesized via a hydrothermal method with glutamic acid ($C_5H_9NO_4$) as a template. The XRD pattern of a calcined sample shows the face-centered cubic fluorite structure of ceria. Transmission electron microscopy (TEM) and the selected-area electron diffraction (SAED) pattern revealed that the submicron cubic mesocrystals were composed of many small crystals attached to each other with the same orientation. The UV-visible adsorption spectrum exhibited the red-shift phenomenon of mesocrystal $CeO_2$ compared to commercial $CeO_2$ particles; thus, the prepared materials show tremendous potential to degrade organic dyes under visible light illumination. With a concentration of a rhodamine B solution of 20 mg/L and a catalyst amount of 0.1 g/L, the reaction showed higher photocatalytic performance following irradiation with a xenon lamp (${\geq}380nm$). The decoloring rate can exceed 100% after 300 min.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.5
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• pp.43-51
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• 1996

An appropriate lighting standard for the museum is needed to minimize the deterioration of the exhibits by the light. To obtain the basic data for the standard, a system to measure the color change of the artifacts as a function of the radiation energy frequency was constructed. Xenon lamp is used as a light source, and the light is irradiated to the samples through serveral cut-off filters. Measuring the colors of the samples under each filters, color change of the samples is estimated for each frequency ranges of radiation energy. As a result, natural dyes show severe color change in a short time, but traditional papers shows relatively small color change. Using measured results, color change due to other light sources can be calculated and this will be the base of the standard.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.181-184
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• 2004

Organic semiconductors have attracted considerable attention due to their interesting physical properties followed by various technological applications in the area of electronics and opto-electronics. It has been a long time since organic solar cells were expected as a low-cost high-energy conversion device. Although practical use of them has not been achieved, technological progress continues. Morphology of the materials, organic/inorganic interface, metal cathodes, molecular packing and structural properties of the donor and acceptor layers are essential for photovoltaic response. We have fabricated solar-cell devices based on copper-phthalocyanine(CuPc) as a donor(D) and fullerene($C_{60}$) as an electron acceptor(A) with doped charge transport layers, and BCP as an exciton blocking layer(EBL). We have measured photovoltaic characteristics of the solar-cell devices using the xenon lamp as a light source.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.149-152
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• 2000

In recent years, various artificial molecular photodiode have been fabricated by mimicking the electron transport function of biological photosynthesis. And now, we have been investigated the protein-organic hetero thin film photodiode using GFP as an sensitizer based on the redox potential difference of functional molecules. In this paper, shows molecular photodiode consisting of green fluorescence protein(GFP). viologen and TCNQ. The TCNQ and viologen were deposited onto ITO coated glass by LB technique. And GFP molecule was adsorption onto the viologen LB film surface by self-assembly method. Finally, The Al deposition onto GFP/viologen/TCNQ film surface was performed to make a top electrode. As a result, The MIM(metal/Insulator/Metal) structured device was constructed. The input light of 460nm wavelength was generated by the xenon lamp system, and then the photocurrent produced from the molecular device was detected through a current-voltage(I-V) measuring unit (SMU Model 236, Keithley, USA). An artificial molecular photodiode using protein(GFP)-adsorbed hetero-LB film is presented as a model system for the bioelectronic device based on the biomimesis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1181-1185
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• 2005

Microstereolithography has evolved from the stereolithography technique, and is also based on a light-induced layer-stacking manufacturing. Integral microstereolithography is proposed for building a 3D microstructure rapidly, which allows the manufacture of a complete layer by one irradiation only. In this study, we developed the integral microstereolithography apparatus based on the use of $DMD^{TM}$ as dynamic pattern generator. It is composed of Xenon-Mercury lamp, optical devices, pattern generator, precision stage, controllers and the control program. Also, we estimated curing characteristics in photopolymer. The relationship between the viscosity of diluent-oligomer solutions and curing width, irradiation time and curing property has been studied.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.285-286
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• 2005

Organic photovoltaic properties were studied in ZnPc/$C_{60}$ heterojunction structure by varying the organic layer thicknesses and exiton blocking layer(EBL). Current density-voltage characteristics of organic photovoltaic cells were measured using Keithley 236 source-measure unit, a 500W xenon lamp (ORIEL 66021) for a light source and Agilent 4294A impedance analyzer in the range of 40 Hz $\sim$ 1 MHz. From the analyses of current-voltage characteristics such as short-circuit current density, open-circuit voltage and power conversion efficiency, optimum thickness of the organic layer were obtained and frequency response such as electrical conductance.