• Journal of the Korean Applied Science and Technology
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• v.15 no.1
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• pp.55-62
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• 1998

The absorption spectra of polyamic acid containing p-methoxyazobenzene in a mixture of N, N-dimethylacetamide(DMAC) and benzene(1:1 by volume) solution was induced photoisomerization by UV and visible light irradiation. This solution is influenced on temperature according to measure by UV-Vis Spectrophotometer. Ultra thin film of polyamic acid containing p-methoxyazobenzene was prepared on the hydrophilic quartz plate by Langmuir-Blodgett(LB) method. The precursor LB film was heated in a vacuum dry oven at $120^{\circ}C$ in order to convert it into the LB film of polyimide. The absorption spectra of LB films were also induced photoisomerization by UV and visible light irradiation.

• Analytical Science and Technology
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• v.8 no.3
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• pp.249-258
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• 1995

The polymers, polyazine, polyazomethine ( I ) and polyazomethine ( II ) were prepared by the condensation of p-benzoquinone with hydrazine hydrate, p-phenylenediamine and diaminomaleonitrile in DMSO, respectively. The IR spectra of these polymers showed a characteristic peak of schiff base (-C=N-) at about $1600cm^{-1}$. These polymers dissolved in concentrated sulfuric acid showed UV/VIS absorption near 300nm indicatiog the presence of iminium ion(>$C\limits^{\small\oplus}=NH-$). Another UV/VIS absorption band in the region of 350~415nm was shown presumably due to the charge transfer transition in the molecule. The electrical conductivities of polyazine, polyazomethine ( I ) and ( II ) were measured. The self-electrical conductivity of these was found to be about $10^{-14}{\sim}10^{-11}{\Omega}^{-1}cm^{-1}$ and these polymers doped with $I_2$ showed the maximum conductivity of about $10^{-2}{\Omega}^{-1}cm^{-1}$.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.522-533
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• 2014

Bionanotechnology has revolutionized nanomaterial synthesis by providing a green synthetic platform using biological systems. Among such biological systems, microalgae have tremendous potential to take up metal ions and produce nanoparticles by a detoxification process. The present study explores the intracellular and extracellular biogenic syntheses of silver nanoparticles (SNPs) using the unicellular green microalga Scenedesmus sp. Biosynthesized SNPs were characterized by AAS, UV-Vis spectroscopy, TEM, XRD, FTIR, DLS, and TGA studies and finally checked for antibacterial activity. Intracellular nanoparticle biosynthesis was initiated by a high rate of $Ag^+$ ion accumulation in the microalgal biomass and subsequent formation of spherical crystalline SNPs (average size, 15-20 nm) due to the biochemical reduction of $Ag^+$ ions. The synthesized nanoparticles were intracellular, as confirmed by the UV-Vis spectra of the outside medium. Furthermore, extracellular synthesis using boiled extract showed the formation of well scattered, highly stable, spherical SNPs with an average size of 5-10 nm. The size and morphology of the nanoparticles were confirmed by TEM. The crystalline nature of the SNPs was evident from the diffraction peaks of XRD and bright circular ring pattern of SAED. FTIR and UV-Vis spectra showed that biomolecules, proteins and peptides, are mainly responsible for the formation and stabilization of SNPs. Furthermore, the synthesized nanoparticles exhibited high antimicrobial activity against pathogenic gram-negative and gram-positive bacteria. Use of such a microalgal system provides a simple, cost-effective alternative template for the biosynthesis of nanomaterials in a large-scale system that could be of great use in biomedical applications.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.6
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• pp.216-219
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• 2003

A new class of carbosiloxane dendrimer (G4-48PyP) terminated with 4-pyridylpropano I was synthesized and its possible application to functional thin films was examined through metal complexation and Langmuir-Blodgett (LB) technique. The highly concentrated periphery pyridyl groups of G4-48PyP were exposed on aq. aluminum ions at the air-water interface. The monolayers showed stability up to ca. 50 mN/m of surface pressure. When the subphase became acidic or alkaline, the monolayers changed to condensed phase. The presence of aluminum ions also caused reduction of the molecular area. The macroscopic images of the monolayers were monitored by Brewster angle microscopy (BAM) and only the images of dendrimer aggregates could be observed after the monolayer collapse. The surface images of the monolayer LB film were scanned by atomic force microscopy (AFM). The convex structures of single and aggregate molecules were directly observed. The structures of Langmuir-Blodgett (LB) films were characterized by FT-IR, UV-Vis, and X-ray photoelectron spectroscopy (XPS). The UV-Vis spectrum of the aluminum ion-complexed LB film showed additional band around 670nm, which was not found in the spectra of dendrimer itself or aq. aluminum ions. XPS spectra also supported the incorporation of aluminum ions into the LB films.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.327-328
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• 2005

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2011.10a
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• pp.109-110
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• 2011

• Advances in nano research
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• v.1 no.2
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• pp.83-91
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• 2013

The synthesis of semiconductor nanoparticles is a growing research area due to the prospective applications for the development of novel technologies. In this paper we have reported the biosynthesis of Cadmium sulfide nanoparticles (CdSNPs) by reduction of cadmium sulphate solution, using the bacteria of Serratia nematodiphila. The process for the synthesis of CdS nanoparticles is fast, novel and ecofriently. Formation of the CdS nanoparticles was confirmed by surface Plasmon spectra using UV-Vis spectrophotometer and absorbance strong peak at 420 nm. The morphology of crystalline phase of nanoparticles was determined from Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy and X-ray diffraction (XRD) spectra. The average size of CdS nanoparticles was in the range of 12 nm and the observed morphology was spherical. The results indicated that the proteins, which contain amine groups, played a reducing and controlling responsibility during the formation of CdS nanoparticles in the colloidal solution. Antibacterial activity against some bacteria such as Bacillus subtilis, Klebsiella planticola. CdS nanoparticles exhibiting good bactericidal activity.

• Journal of the Korean Ceramic Society
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• v.34 no.9
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• pp.993-1001
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• 1997

The (0.8PPV+0.2DMPPV) copolymer and silica/borosilicate composites were synthesized by sol-gel process. The organic-inorganic hybrid solution was prepared by using of (0.8PPV+0.2DMPPV) copolymer precursor solution as a raw material for organic components and TEOS and TMB for glass components. Then by drying the solution in vacuum at 5$0^{\circ}C$ for 7days and subsequent heat treatment in vacuum at 15$0^{\circ}C$~30$0^{\circ}C$ for 2h~72h with heating rate of 0.2$^{\circ}C$/min and 1.8$^{\circ}C$/min, the organic-inorganic composites were synthesized. Microstructural evolution of the composites was characterized by DSC, IR spectrocopy, UV/VIS spectroscopy, and TEM. Elimination of the polymer precursor and degradation of the polymer were observed by DSC and Si-O and trans C=C absorption peaks were identified by IR spectra. The polymer was found to be successfully incorporated into the glass matrix and it was confirmed by the absorption peaks from the polymer in the UV/VIS spectra and the TEM results. The absorption peak of the composites was found to shift toward short wavelength side compared to that of the pure polymer and the amount of the blue shift increased with increasing the heat treatment temperature and heat treatment time and with decreasing the heating rate.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.296-301
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• 1999

Different papers such as toilet and towel tissue, newsprint and copy paper made from reclaimed fibres were characterized using UV-VIS reflectance and fluorescence spectroscopy. The emission properties of the extracts of the papers were also evaluated. Photochemical irradiation at ambient temperatures, and thermal aging of the copy papers at 105$^{\circ}C$ and 150$^{\circ}C$ were performed. Post-colour numbers (PC) were calculated from the reflectance values measured from the corresponding UV-VIS reflectance spectra. Light absorption coefficient spectra were calculated before and after irradiation, and the changes in absorption coefficient were related to the content of chromophores in the papers. Photochemical and thermal discolouration of the copy papers, similar to that of virgin fibres, was readily observed. The influence of changes in the concentrations of fluorescent brightening agents and dyes on the spectral properties was also assessed. Photostabilization studies of the copy papers were performed with the use of polymer additives polyethylene glycol (PEG) and polytetrahydrofuran (PTHF).

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1227-1233
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• 2000

Lycopene was subjected to ozonolysis in ice-cold dichloromethane. The ozonolysis products were fractionated with a silica column and the carbonyl fraction was analyzed by ODS-HPLC with a photodiode array detector and by LC-MS. UV-vis spectra and $[M+H]^+$ of the carbonyl compound peaks showed clearly that acycloretinal, apo-14'-lycopenal, apo-12'-lycopenal, apo-10'-lycopenal, apo-8'-lycopenal and apo-6'-lycopenal were formed by ozonolysis of lycopene. Lycopene was solubilized in toluene and aqueous Tween 40, and then oxidized by incubating at $37^{\circ}C$ under atmospheric oxygen. Carbonyl compounds were produced. In comparison with autoxidation and ozonolysis, each compound showed the same retention time and UV-vis spectra are identical to the reference cleavage products prepared by ozonolysis of lycopene. Thus, eccentric cleavage of lycopene was confirmed to occur in vitro under oxidation condition.