• Fibers and Polymers
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• v.1 no.1
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• pp.1-5
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• 2000

Poly(3-methyltetrahydrofuran)(3-MTHF) and poly(tetrahydrofuran-co-3-MTHF), having very narrow molecular weight distribution were successfully synthesized via photo-induced living cationic polymerization in the presence of diphenyliodonium hexafluorophosphate. Linear relationship between % conversion and number average molecular weight of resulting poly(3-MTHF) in the polymerization of 3-MTHF, carried out at -22$^{\circ}C$, indicates that the 5-membered cyclic oxonium ion, being responsible for the cationic propagation is stabilized by ion pall formation with hexafluorophosphate anion, supplied from the salt. The linear relationship between two parameters, mentioned above was also observed in the copolymerization of 3-MTHF with THF, carried out at 0 and -22$^{\circ}C$. The molecular structures including the copolymer composition and average molecular weight and its distribution is determined by reaction parameters such as monomer feed ratio and reaction temperature.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.386-389
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• 1989

Phosphorus nitride films on InP surface were grown by a Photo-CVD (chemical vapor deposition) technique over 100-250 $^{\circ}C$ range of substrate temperature, which is based on direct photolysis of $PCl_3/H_2$ and $NH_3$ gas mixtures by 185nm ultraviolet light from a low pressure mercury lamp. The film growth rate ed the refractive index(n) were shown about 700-800 ${\AA}/hr$ and 1.7-1.8, respectively. Composition ratio and interface properties were analyzed by AES(Auger Electron Spectroscopy) and XPS (X-ray Photoelectron Spectorscopy) technique.

• Transactions of the Korean hydrogen and new energy society
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• v.1 no.1
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• pp.9-14
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• 1989

Mixed photocatalyst containing cadmium sulfide and zinc sulfide was prepared on silica gel powder and Nafion film. Photo-irradiation of aqueous mixture containing the photocatalysis generated hydrogen by water cleavage reaction. Use of sodium sulfide as sacrificial reagent help the photo-reaction. Evolution of the hydrogen was measured by gas chromatographic analysis. Composition of the catalyst was determined by atomic absorption spectrophotometer. 0.2 mL of of hydrogen was generated per hour. The maximun catalytic activity was obtained after 8-12 hours later. Hydrogen generation efficiency by the two different catalytic system was compared and showed that the Nafion-based catalyst is more efficient than the silicagel-based catalyst for the photoreaction.

• Archives of design research
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• v.16 no.3
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• pp.263-272
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• 2003

Motiongraphics is not short film and has a special communication method characteristic of design. As graphic design needs space-composition, motiongraphics requires time-composition. In the 1920's, artists belonged Bauhaus in Germany tried to realize time-composition in the plans for abstract animation. At that time the russian film director Eisenstein experimented with moving image composit on, creating new meanings through the montage of heterogeneous images. In the digital era of today, motiongraphics is composed of such various elements as moving image, photo, illustration, typography, etc. The editing in montage film is one-dimensional. Meanwhile, motiongraphics of these days consists of a lot of layers, composing various elements by editing. Motiongraphics needs time structure and visual rhythm as well as scenario or storyboard for time composition. The principle of time composition in motiongraphics ist similar to that of musical composition. If we compare the time composition of abstract animation or montage film with the melody in a solo, time composition for motiongraphicf is like a symphony. Various composing elements are developed under different tempos at the same time.

• Journal of the Korean Society of Earth Science Education
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• v.13 no.2
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• pp.134-146
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• 2020

The purpose of this study is to examine how elementary pre-service teachers have a perception of 'science'. Especially, this study used photo-narrative method to analysis pre-service teachers' perception of 'science'. Photo-narrative is a way of describing what a study participant wants to say by taking a picture. Participants were 66 elementary pre-service teachers. The results of this study were as follows: First, elementary pre-service teachers used many words such as people, life, everyday as well as scientific terms such as phenomena and principles to explain science. Secondly, the pictures used by elementary pre-service teachers to explain science included household goods, natural phenomena, advanced devices, and living things. Third, elementary pre-service teachers explained science with knowledge of science, knowledge, convenience, and nature of science. As a result of this study, it was found that elementary pre-service teachers recognized that science is closely related to life and that it is necessary for learning. The results of this study can contribute not only to curriculum composition and curriculum content of elementary and middle school science education but also to curriculum development for teacher training.

• Korean Journal of Optics and Photonics
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• v.21 no.1
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• pp.6-11
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• 2010

Fluorescent photopolymer film was prepared with composition containing acrylate monomer, binder, a visible light sensitive photo initiator, and fluorescent anthracene polymer. A fluorescent grating pattern was inscribed on the photopolymer film using a 2-beam coupling method. A 514 nm laser was coupled to generate a beam-interference pattern. A highly fluorescent diffractive line pattern was formed on the fluorescent photopolymer within 30 sec. of exposure. The fluorescence intensity was highly enhanced in the patterned area, possibly due to the change in the environment of the fluorescent polymers by the photo-polymerization of monomers. Under a photo-mask, a gap electrode pattern was formed of fluorescent gratings with a sub-micron scale, which was matched well to the calculated value ($2.5\;{\mu}m$ and $0.6\;{\mu}m$) based on the refractive index of the photopolymer and beam incident angle ($3.4^{\circ}$, $15^{\circ}$) to the photopolymer surface.

• Analytical Science and Technology
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• v.17 no.3
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• pp.225-229
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• 2004

The effect of the silicon acrylate as a reactive additive on the UV-curing photopolymerization reaction was studied by micro raman technique. For the study, acrylate systems and Darocur 1173 were used as oligomer and monomers, and a photo initiator, respectively. The content of silicon acrylate was within the range of 0-3 wt%. The extent of photo-polymerization reaction as a function of depth from the air interface was obtained from the conversion ratio of acrylate double bond calculated from the intensities of measured bands at $1410cm^{-1}$ and at $1635cm^{-1}$. Micro raman spectroscopic technique can be an useful tool for the investigation of the factors, which can affect the reaction progress, such as oxygen inhibition, composition of the formulations, depth, etc.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.5
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• pp.435-440
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• 2002

In this study, we have investigated photo-induced changes of optical energy gap( $E_{OP)}$ and photoluminescence (PL) in amorphous ($\alpha$-) S $e_{100-x}$G $e_{x}$ (x=5, 25 and 33) thin films prepared by conventional thermal evaporation method. In the $\alpha$-S $e_{100-x}$G $e_{x}$ thin film, the $E_{OP}$ is obtained by a linear extrapolation of the ($\alpha$hν)$^{\frac{1}{2}}$ versus hν plot to the energy axis using the optical absorption coefficient ($\alpha$) calculated from the extinction coefficient k measured in the wavelength range of 290~900nm. Although the values of $\Delta$ $E_{OP}$ are very different, all films exhibit photo-induced photo-darkening (PD) effect that is a red shift of $E_{OP}$ . In particular, $\Delta$ $E_{OP}$ in $\alpha$-S $e_{75}$ G $e_{25}$ thin film exhibits the largest value (i, e., $\Delta$ $E^{OP}$ ~40meV for $\alpha$-S $e_{95}$ G $e_{5}$ , $\Delta$ $E_{OP}$ ~200meV for $\alpha$-S $e_{75}$ G $e_{25}$ , $\Delta$ $E_{OP}$ ~130meV for $\alpha$-S $e_{67}$ G $e_{33}$ ). PL spectra in $\alpha$-SeGe by hν$_{HeCd}$ have no-Stokes shift (SS) and show a tendency dependent on both composition and illumination time. We explain the energy-induced phenomena such as the PD and thermal bleaching, the native charged-defect generation and the no-SS PL, etc..the PD and thermal bleaching, the native charged-defect generation and the no-SS PL, etc..tc..

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.9-21
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• 2014

In this paper, we propose the auto correction technique of photography composition by which the eye line is concentrated and the stable image of the structure can be obtained in case the general user takes a picture. Because the general user photographs in most case without background knowledge about the composition of the photo, the subject location is not appropriate and the unstable composition is contrasted with the stable composition of pictures which the experts take. Therefore, we provide not the method processing the image after photographing, but he method presenting automatically the stable composition when the general users take a photograph. The proposed method analyze the subject through Saliency Map, Image Segmentation, Edge Detection, etc. and outputs the subject at the location where the stable composition can be comprised along with the guideline of the Rule of Thirds. The experimental result shows that the good composition was presented to the user automatically.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.1
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• pp.21-27
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• 2000

We used the surface photovoltage spectroscopy(SPVS) for characterization of GaAs/Al\ulcornerGa\ulcornerAs multi-quantum well(MQW) structures grown by molecular beam epitaxy(MBE) method. Energy gap related transitions in GaAs and AlGaAs were observed. The Al composition(x=0.3) was determined by Sek's composition formula. Transition energies in MQW were determined using the differential surface photo-volatage spectroscopy)DSPVS) of the measured resonanced. In order to indentify the transitions, the experimentally observed energies were compared with results of the envelope function approximation for a rectangular quantum well. We have observed and interesting behavior of the temperature dependence(80K~300K) of the 11Hand 11L transition for sample.