• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.34-37
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• 2002

Freestanding azobenzene-containing liquidcrystalline network (LCN) films. with macroscopic uniaxial molecular alignment were prepared by insitu photopolymerization. By polarizing microscopy, fiber-like structures aligned in one direction were observed. Furthermore, with a confocal laser scanning microscope (CLSM), it was confirmed that the fiber-like structures were formed even in the bulk of the LCNs. Upon UV light irradiation to cause trans-cis photoisomerization of the azobenzene molecules, the LCNfilms underwent a significant and anisotropic bending toward the irradiation direction of UV light. When the bent LCNfilms were exposed to Vis light, unbending of the LCN films immediately took place and the initial flat LCN films were restored. This bending and unbending behavior of the LCN films could be repeated just by changing the wavelength of the irradiation light. It was suggested that the bending was induced by an absorption gradient which produced a volume difference between the front surface area and the bulk of the network films.

• Journal of Pharmaceutical Investigation
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• v.12 no.4
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• pp.132-144
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• 1982

The inclusion of ${\beta}-cyclodextrin$ $({\beta}-CyD)$ with prothionamide in aqueous phase was investigated by circular dichroism(CD), ultraviolet (UV) absorption, and solubility technique. The results suggested that a region of drug chromophore was located within the asymmetric center of ${\beta}-cyclodextrin$. Solubility and spectral changes were quantitatively treated to obtain stoichiometric ratio, which was found to be 1 : 1, and formation constants which were determined by solubility, CD, and UV method were 257, 367, and 389 $M^{-1}$, respectively. Also, the formation constant of the inclusion complex was determined by CD method at various pH. The result was that $K_c$ depended upon the pH of medium, and this fact also supported that thioamide moiety was accomodated in the cavity of ${\beta}-cyclodextrin$.

• Biomolecules & Therapeutics
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• v.6 no.3
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• pp.256-260
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• 1998

-7-o-p-Fluorobenzoylchrysin was synthesized by condensing p-flouorbenzoic acid with chrysin in organic solvent, and its structure was identified by NMR, MS, UV, and IR. We also investigated the physicochemical properties, hypoglycemic effect, and the quantitative analysis method of this compound. The correlation coefficient of calibration curve on this compound was approximately 0.9945 by absorption spectrophotometry and 0.9989 by high perfornance liqid chromatography 7-o-p-Fluorobenzoylchrysin was resolved in 6.014 min by reversed-phase HPLC column with solvents consisting of methanol (80%) and 10mM phosphoric acd. Its blood glucose inhibition rate is 20.7%.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.282-282
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• 2010

We report a new method of fabrication of polydiacetylene nanowire using liquid bridge-mediated nanotransfer molding (LB-nTM), a direct patterning method for the formation of two- or three-dimensional structures with feature sizes between tens of nanometers and tens of micron over large areas with various materials from a molder to a substrate via a liquid bridge between them. First, we fabricate assembled diacetylene monomer nanowire on the substrate then make it polymerize using 254nm UV-light irradiation. The Polydiacetylene nanowires have been investigated by UV-visible absorption spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM).

• Tribology and Lubricants
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• v.26 no.3
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• pp.167-174
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• 2010

An apparatus for measuring oil oxidation was developed, which is capable of being mounted to mechanical devices for detecting power of fluorescent light reflected from oil in real time as an indication of the oil oxidation. This device has an advantage over conventional fluorescence spectrometers where the thin film is required for the measurement. Clean and used oil samples (mineral and synthetic oils) were tested by the developed apparatus that calculates a fluorescence quantum yield and a light absorption coefficient of the oil based upon the signals from the two light-receiving members and evaluates the degree of oil oxidation of test oils based on the fluorescence quantum yield. Results generally show that the developed device is able to effectively evaluate oil oxidation characteristics on-site in the field.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.72.1-72.1
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• 2011

We investigate the relation between AGN gas metallicity and their host galaxy stellar metallicity using a sample of local Seyfert 1 galaxies. Stellar metallicity is measured from stellar absorption lines while AGN gas metallicity is derived from the flux ratios of UV emission lines. We use a high quality spectra obtained from the Lick AGN Monitoring Project, to obtain pure host galaxy spectra based on the spectral decomposition analysis, leading to accurate measurements of the Mg2 (5175) and Fe (5270) indices. In the case of AGN gas metallicity, we measure the ratio of NV1240 to CIV1549 lines using UV spectra from the archival IUE and HST STIS data. We will present the results of metallicity measurements and comparison between AGN and stellar metallicity, and discuss the implications of the results.

• Journal of Integrative Natural Science
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• v.3 no.4
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• pp.197-201
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• 2010

Dihydrotetraphenylgermole has been synthesized from the reduction of dichlorotetraphenylgermole with lithiumaluminiumhydride. UV-Vis absorption and photoluminescence was measured by using UV-Vis and fluorescence spectroscopy. Nanoparticles of dihydrotetraphenylsilole were synthesized from the mixture solution of water and THF. Photoluminescence behavior of organogermanium nanoparticle was investigated at various water fractions. Critical fraction of water to form organogermanium nanoparticles was 60%. Photoluminescence intensity of organogermanium nanoparticle was increased as the concentration of organogermanium nanocolloids increased. Photoluminescence efficiency of organogermanium nanoparticle at 90% water fraction increased about 100 times compared to that of molecular state.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1714-1716
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• 2000

We fabricated the optical system of merocyanine dye using Langmuir-Blodgett(LB) technique because quite uniform orientation could be obtained, which is one of the most important factors to affect to its optical characteristics. The resonance frequency and other electrical parameters at the parallel resonance state were measured using the impedance analyser(HP 4294 A). Also the morphological changes of dye molecules after UV irradiation were observed using AFM. The parallel resonance frequency and resistance by electrical equivalent circuit were decreased with the UV irradiation and these aspects are different from general mass adsorption process. Therefore the structural changes of dye molecules are being considered, that is, the aggregated molecules become dissociated. It indicates that the shifts of the resonance frequency and the others occurred without mass absorption.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.925-928
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• 2010

Nitrogen-doped $TiO_2$ ($TiO_2$:N) nano-particles with a pure anatase crystalline structure were successfully synthesized through the hydrolysis of $TiCl_4$ in an ammonia aqueous solution. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), $N_2$-sorption, and UV-vis diffuse reflectance spectra (UV-vis DRS) techniques. The absorption edge of nitrogen-doped $TiO_2$ shifted into the visible wavelength region. The photoelectrochemical (PEC) performances were investigated for the $TiO_2$ mesoporous electrodes doped with different nitrogen concentrations. The $TiO_2$:N electrodes exhibited much higher PEC responses compared to the pure $TiO_2$ electrode because of the significantly enhanced visible-photoresponsibility of the $TiO_2$:N electrodes.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.316-316
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• 2010

Six metal-free organic dyes having thiophene (1), benzene-thiophene (2), thiophene-benzene (3), thiophene-pyridine(4), thiophene-thiophene (5), and pyridine (6) linkers between 9,9-dimethylfluorenyl terminal group and $\alpha$-cyanoacrylic acid anchor were synthesized. Among them, organic dye 5 showed the longest ${\lambda}}max$ value (424 nm) in UV-Vis absorption spectrum, better incident monochromatic photon-to-current conversion efficiency (IPCE), highest short circuit photocurrent density (JSC, 9.33 mA2/cm2), and highest overall conversion efficiency ($\eta$, 3.91%).