• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.90-90
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• 2011

Transparent conducting oxide (TCO) films have been intensively utilized in the electric applications, such as, displays, lightings and solar cells due to the good electric conductivity with an excellent transmittance of the visible light. We, herein present an excellent Al-doped ZnO film (AZO), which has been fabricated by co-sputtering method. An as-deposited AZO film had an optical transmittance of 84.78% at 550 nm and a resistivity of $7.8{\times}10^{-3}{\Omega}cm$. A rapid annealing process significantly improved the optical transmittance and electrical resistivity of the AZO film to 99.67% and $1{\times}10^{-3}{\Omega}cm$, respectively. The fabricated AZO film was fabricated for a metal-semiconductor-metal (MSM) structure. The AZO film-embedding MSM device was highly responsive to a UV light.

• Journal of Powder Materials
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• v.15 no.1
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• pp.13-17
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• 2008

Visible-light responsive $TiO_2$:Zr, N powders were prepared by polymer complex solution method and the particle properties were characterized by using transmission electron microscope, BET method, X-ray diffractometer and UV-Vis spectrophotometer. The photocatalytic reactivity of the catalysts was also estimated by analyzing NO degradation. Polyhedral $TiO_2$ powder having about 20 um in the average particle diameter was successfully prepared, The XRD analysis revealed that the as-prepared powder consisted of anatase and rutile phases. The light absorption of the as-prepared $TiO_2$:Zr, N powder was shifted to the visible light. In addition, the as-prepared $TiO_2$:Zr, N nanoparticles showed the higher photocatalytic activity than the commercial $TiO_2$ under both UV and visible lights.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.65-70
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• 2012

Structural changing materials which can induce the physical deformation of materials are interesting research topics with various potential applications. Particularly, light among many driving mechanisms is a non-contact energy source, hence the light-responsive system can be used where non-destructive, local irradiation, and remote control is needed. Here, a mainchain azobenzene polymer is synthesized and its physical and optical properties are observed and compared to that of a polymer having a light-responsive azobenzene moiety on its side chain. Further dispersion onto polyvinylalcohol hydrogel is made and its dual stability and actuation are observed upon UV-visible light irradiation. Extended azobenzene polymer blend films show an anisotropic light-actuation with non-polarized UV light at room temperature. This physical shape change is quite reversible and occurs at lower temperature than that of any other reported systems including liquid crystalline elastomers. It is successfully demonstrated that the simple physical azobenzene/polymer blending has a very good actuation compared to that of LCEs which need an elaborate chemical design and it can be further used in the areas requiring a dimensional shape change.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.571-575
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• 2016

Photo responsive polymer(PRP) is well known for its photo deformation under UV light, and goes back to its original shape in visible light due to the photoisomerization of the azobenzene inside the PRP. In this paper, dynamic study of the vibration in PRP is discussed. In order to predict photo-deformation of the PRP a multiscale modeling is introduced which covers quantum level photo excitation, microscopic morphology, and macroscopic deformation of the PRP. A simple 1D beam model is introduced to model dynamic bending behavior of the PRP. Through fast Fourious transformation analysis, we identify that vibration frequency of the PRP can be controlled by light polarization angle.

• Journal of the Korean Chemical Society
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• v.61 no.4
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• pp.168-178
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• 2017

$La/TiO_2$ - graphene composites were synthesized in this study, and applied to the photocatalytic degradation of Rhodamine B (RhB) under UV-visible light irradiation. X-ray diffraction (XRD), surface analysis, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and Transmission electron microscopy (TEM) analysis demonstrated that $La/TiO_2$ nanoparticles were well distributed on the surface of graphene, and formed the heterostructure of $La/TiO_2$-graphene. Compared to the pure $TiO_2$, $La/TiO_2$-graphene composites displayed much higher photocatalytic activities in RhB degradation under UV-visible light irradiation. The photocatalytic data of $La/TiO_2$-graphene composites exhibit extended light absorption in the visible light region, and possess better charge separation capability than that of pure $TiO_2$. The high photocatalytic activity was attributed to the composite's high adsorptivity, extended light absorption, and increased charge separation efficiency, due to the excellent electrical properties of graphene, and the large surface contact between graphene and $La/TiO_2$ nanoparticles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.8-11
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• 2003

We propose that when combustible burn with contain carbon, introduce fire detector with sensor of private-use detectable light energy as infrared and ultraviolet in energy of electromagnetic-wave type radiate from flame, method for correct discrimination to resemble fire produce false alarm of detector such as sun light, hot object radiation, are welding. This research using infrared sensor is pyroelectric infrared sensor based black body radiation theory. Ultraviolet sensor is uv Tron using gas multiplication effect to current discharge and photoelectric effect of metal. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research introduced UV/IR compound type flame detector and proposed method of false alarm reduced to resemble fire. The result propres the prevention and extinction of fire technique degree, certificated operation of detector.

• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.7-13
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• 2006

Plastichouse cultivation for crops and vegetables in the winter has been widely popularized in Korea. In the vinylhouse Ultraviolet B penetration is lower than in the field, and so some problems, as plant overgrowth and outbreak of disease, occurred frequently. The effect of artificial supplement ultraviolet B $(UV-B:280{\sim}320nm)$ radiation on the physiological responses and yield of perilla (perilla frutescens) was investigated UV-B ray was radiated on perilla with the 10th leaf stage at the distance of 90, 120 and 150 cm from the plant canopy for 30 days after planting in the vinylhouse. The production of fresh perilla leaves was high in the order of plastic house, ambient+50% of supplemental UV-B, ambient ambient+100% of supplemental UV-B. Enhanced UV-B radiation affected the intensity of thirty-three proteins in 2-dimensional electrophoretic analysis of proteins and ten proteins out of them seemed to be responsive to UV-B : a protein was, ATP synthase CF1 alpha chain, down regulated and nine proteins (Chlorophyll a/b bindng protein type I, Chlorophyll a/b binding protein type II precursor, Photosystem I P700 chlorophyll a apoprotein A2, DNA recombination and repair protein recF, Galactinol synthase, S-adenosyl-L-methionine, Heat shock protein 21, Calcium-dependent protein kinase(CDPK)-like, Catalase) were up-regulated.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.462-466
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• 2012

$\beta$-cyclodextrin ($\beta$-CD) polymers were prepared in a strong alkali condition solution (NaOH solution 30% (w/v)) using epichlorohydrin (EPI) as a cross-linker, and the molar ratio of EPI to $\beta$-CD was 10 : 1. The $\beta$-CD content in $\beta$-CD polymers is about 52%. In order to get the photo-responsible and pH-responsible, cinnamic acid was added to be inserted into the cavities of $\beta$-CD due to the hydrophobic interaction. The complex formation was confirmed using transmission electron microscope. The dimerization degree of complexes increased under UV irradiation at $\lambda$ = 365 nm but decreased under the UV irradiation at $\lambda$ = 254 nm. Dynamic light scattering analysis of particle sizes showed that the sizes of complexes did not change with different UV wavelength. Moreover, the complexes were pH-responsible because of the carboxyl group of cinnamic acid, but the size and zeta potential of the complex did not change in strong acid and alkali conditions.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.35-35
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• 2011

The design and preparation of novel dye rotaxanes have gained much interest recently, since such structure usually exhibits peculiar spectral and optical changes. In spite of the promising results to date, increasing pressure remains to develop novel supramolecular structures based on stimuli-responsive systems. This presentation covers the study of inclusion complexes of cyclodextrins and various chromophores, with an emphasis on our most recent outcome of anisotropic hydrogel. In this system, physical gelation prepared from simple mixture of CD and a azo dye is completed through specific host-guest interaction. The obtained hydrogel exhibits respective morphological transitions based on supramolecular assembly and dissociation, leading to either precipitation or a sol-to-gel transition. It can identify different classes of metal ions, and, among them, naked-eye differentiation of lead ion is possible due to the coordination-induced unthreading of dye molecules. Accompanying structural changes were verified by numerous characterization techniques, including 2D-ROESY, HR-MAS, UV-Visible absorption, small-angle X-ray scattering, and induced circular dichroism measurements. Such properties discussed here will find useful in analytical applications, such as metal ion sensing and removal applications.

• Textile Coloration and Finishing
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• v.27 no.4
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• pp.340-344
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• 2015

The interaction between curcumin(1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) and ethylamines was studied in DMSO:$H_2O$(5:1, v/v) using absorption and fluorescence measurements. The association constant, $K_{ass}$, and the Stern-Volmer constants were calculated by the Benesi-Hildebrand and Stern-Volmer equation, respectively. Curcumin displayed marked UV-Vis absorption changes and highly responsive fluorescence quenching in the presence of ethylamine and the quenching ability was enhanced almost linearly with the concentration of ethylamines. The apparent Stern-Volmer constant measured for the ethylamine-curcumin system was about 1000-fold greater than that of the triethylamine-curcumin system, indicating considerably greater quenching efficiency of ethylamines.